Bag moisture curing reaction type polyurethane hot melt adhesive and preparation method thereof

Abstract

The invention relates to the field of polyurethane hot melt adhesives, and particularly discloses a moisture-curing reaction type polyurethane hot melt adhesive for bags and suitcases and a preparation method of the moisture-curing reaction type polyurethane hot melt adhesive. The moisture-curing reaction type polyurethane hot melt adhesive is prepared from the following raw materials in parts by weight: 10 to 20 parts of polyether polyol, 40 to 60 parts of polyester polyol, 20 to 50 parts of isocyanate, 0.5 to 1.5 parts of a catalyst, 10 to 20 parts of tackifying resin, 3 to 5 parts of a viscosity stabilizer, 1 to 3 parts of pentaerythritol diacrylate, 5 to 10 parts of an auxiliary agent and 3 to 5 parts of a coupling agent, according to the moisture-curing reaction type polyurethane hot melt adhesive for the bags and suitcases, the polyether polyol, the polyester polyol and the isocyanate react to generate a polyurethane prepolymer, so that the hot melt adhesive has relatively good flexibility and durability; and the tackifying resin, the pentaerythritol diacrylate and the viscosity stabilizer are used for promoting the polyurethane hot melt adhesive to have better initial adhesion and final adhesion strength, so that the polyurethane hot melt adhesive can be firmly adhered to a base material more quickly.

Description

Technical Field

[0001] The present application relates to the field of polyurethane hot melt adhesives, and in particular to a bag moisture-curing reactive polyurethane hot melt adhesive and a preparation method thereof. Background Art

[0002] Bags are indispensable items in daily life, and adhesives are needed to bond various parts during their manufacturing process. Currently, the adhesives commonly used in the market are mostly ordinary polyurethane adhesives or chloroprene adhesives. Although these adhesives can meet certain bonding requirements, they often have poor bonding effects in humid environments and are prone to debonding.

[0003] Moisture-curing reactive polyurethane hot melt adhesive (PUR) is a high-viscosity one-component polyurethane adhesive, the main component of which is an isocyanate-terminated polyurethane prepolymer, which is generally prepared by the reaction of isocyanate monomers, various polyethers or polyester polyols. Initial adhesion is one of the important performance indicators of adhesives for luggage, but traditional PUR hot melt adhesives often have low initial bonding strength and later adhesion, and rebound at high temperatures, which cannot meet the use requirements in the luggage field. Summary of the invention

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

[0005] In the first aspect, the present application provides a moisture-curing reactive polyurethane hot melt adhesive for luggage, which adopts the following technical solution: A moisture-curing reactive polyurethane hot melt adhesive for luggage 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 catalyst, 10-20 parts of tackifying resin, 3-5 parts of viscosity stabilizer, 1-3 parts of pentaerythritol diacrylate, 5-10 parts of auxiliary agent and 3-5 parts of coupling agent.

[0006] By adopting the above technical scheme, polyether polyol is used as a soft segment to generate a polyurethane prepolymer with isocyanate, providing good flexibility and hydrolysis resistance. Polyester polyol is also a 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 use of tackifying resin and viscosity stabilizer enables the polyurethane hot melt adhesive to maintain good bonding strength for a long time and improve the later bonding strength of the polyurethane hot melt adhesive. The hydroxyl group and acrylate group of pentaerythritol diacrylate can react with the polyurethane prepolymer to form additional chemical bonds, enhance the cohesion of the hot melt adhesive, and form a strong bond faster when contacting the luggage substrate, thereby improving the initial adhesion and later bonding strength of the hot melt adhesive. At the same time, pentaerythritol diacrylate can cause the hot melt adhesive to form a denser network structure during the curing process, enhance the adhesion and final bonding strength between the hot melt adhesive and the substrate, and improve the durability of the hot melt adhesive.

[0007] Preferably, the viscosity stabilizer is polyphosphoric acid.

[0008] By adopting the above technical solution, polyphosphoric acid is used as a viscosity stabilizer to reduce the side reaction between the NCO group in the polyurethane prepolymer and moisture, thereby stabilizing the bonding strength of the polyurethane hot melt adhesive in a humid environment and improving the bonding strength of the later polyurethane hot melt adhesive.

[0009] Preferably, the coupling agent is one of 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethylsilane and γ-(methacryloyloxy)propyltrimethylsilane.

[0010] By adopting the above technical scheme, 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethylsilane and γ-(methacryloyloxy)propyltrimethylsilane are added to the polyurethane hot melt adhesive raw materials, which can react with the polyurethane prepolymer through active groups such as amino, epoxy, methacryloxy and silane groups to form chemical bonds, thereby enhancing the cohesion of the polyurethane hot melt adhesive and enhancing the later adhesion and hydrolysis resistance of the hot melt adhesive.

[0011] Preferably, the coupling agent has a blocking rate in the range of 13-17%.

[0012] By adopting the above technical solution and adjusting the coupling agent end-capping rate within a suitable range, the polyurethane hot melt adhesive can have both good initial adhesion strength and final adhesion strength. A low end-capping rate can easily cause the polyurethane hot melt adhesive to have low melt viscosity and low initial adhesion strength. A high end-capping rate can easily cause poor fluidity, high melt viscosity, difficulty in gluing, and reduced final adhesion strength.

[0013] Preferably, the auxiliary agent includes an antioxidant and a leveling agent.

[0014] Preferably, the tackifying resin is one of polyacrylic acid resin, petroleum resin and disproportionated rosin resin.

[0015] By adopting the above technical solution, polyacrylic acid resin, petroleum resin, and disproportionated rosin resin are added to the hot melt adhesive raw materials as tackifying resins, which can form a uniform mixture with the polyurethane prepolymer, have a low softening point, improve the fluidity and wettability of the polyurethane hot melt adhesive, enhance the initial adhesion, heat resistance and chemical resistance of the polyurethane hot melt adhesive, and enable the polyurethane hot melt adhesive to better adapt to the bonding environment of luggage and bags and high temperature and humidity. Disproportionated rosin resin can maintain a good curing speed of the hot melt adhesive, improve the cohesive force of the hot melt adhesive, and enhance the bonding durability and final bonding strength of the hot melt adhesive.

[0016] Preferably, the disproportionated rosin resin is modified by volume expansion, and the volume expansion modification method comprises the following specific steps: preheating and melting the disproportionated rosin under an inert gas, then adding a modification catalyst and a polyol to form a reaction liquid, heating the reaction liquid to 230-250° C. for reaction, stirring evenly until the acid value of the reaction liquid remains unchanged, and cooling the reaction liquid to obtain a modified disproportionated rosin resin.

[0017] By adopting the above technical scheme, 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, the wettability of the polyurethane hot melt adhesive can be improved, and then the bonding strength and durability of the hot melt adhesive can be improved.

[0018] In the second aspect, the present application provides a method for preparing a moisture-curing reactive polyurethane hot melt adhesive for luggage, using the following technical solution: A method for preparing a moisture-curing reactive polyurethane hot melt adhesive for luggage comprises the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer, pentaerythritol diacrylate and auxiliary agent, melting and mixing at 80-120° C., vacuum dehydration, then adding isocyanate under the protection of nitrogen for heating reaction, and finally adding a catalyst and a coupling agent for heat preservation reaction to obtain the moisture-curing reactive polyurethane hot melt adhesive for luggage.

[0019] By adopting the above technical scheme, the prepared polyurethane hot melt adhesive has both good initial adhesion strength and final adhesion strength, can better adapt to the bonding environment of luggage and bags, high temperature and humidity, and has good bonding durability.

[0020] Preferably, the reaction temperature is 100-120°C.

[0021] In summary, this application has the following beneficial effects: 1. Since the present application uses polyether polyol, polyester polyol and isocyanate to react to generate polyurethane prepolymer, it provides good flexibility and durability for the hot melt adhesive. The use of tackifying resin and viscosity stabilizer enables the polyurethane hot melt adhesive to maintain good bonding strength for a long time, thereby improving the final bonding strength of the polyurethane hot melt adhesive. The use of pentaerythritol diacrylate enables the hot melt adhesive to form a firm bond with the substrate more quickly, thereby improving the initial adhesion of the hot melt adhesive.

[0022] 2. In this application, 3-aminopropyl triethoxysilane, γ-(2,3-epoxypropoxy)propyl trimethylsilane and γ-(methacryloyloxy)propyl trimethylsilane are used as coupling agents to be added to the polyurethane hot melt adhesive raw materials, react with the polyurethane prepolymer, enhance the cohesion of the polyurethane hot melt adhesive, and enhance the later adhesion of the hot melt adhesive. At the same time, adjusting the end-capping rate of the coupling agent within a suitable range can enable the polyurethane hot melt adhesive to have both good initial adhesion strength and final adhesion strength. DETAILED DESCRIPTION

[0023] The present application is further described in detail below with reference to the embodiments.

[0024] All raw materials in the examples are commercially available. Example

[0025] Example 1 The present embodiment provides a wet-curing reactive polyurethane hot melt adhesive for 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 auxiliary agent, 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, and the hydroxyl value is 20 mgKOH / g, the isocyanate is diphenylmethane diisocyanate, the catalyst is dimorpholine diethyl ether, the tackifying resin is polyacrylic resin, the viscosity stabilizer is erucic acid, the auxiliary agents are antioxidant 1010 and leveling agent BYK-333, and the coupling agent is 3-aminopropyltriethoxysilane.

[0026] The preparation method of the moisture-curing reactive polyurethane hot melt adhesive for luggage comprises the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer, pentaerythritol diacrylate and auxiliary agent, melting and mixing at 100°C, vacuum dehydration, then adding isocyanate under the protection of nitrogen and heating to 120°C for reaction, finally adding catalyst and coupling agent and reacting at 120°C for 2h, wherein the end-capping rate of coupling agent reaches 15%, thereby obtaining the moisture-curing reactive polyurethane hot melt adhesive for luggage.

[0027] Example 2 The difference between Example 2 and Example 1 is that the amount of polyether polyol used in the raw material of the moisture-curing reactive polyurethane hot melt adhesive for luggage is 10 kg, the amount of polyester polyol used is 60 kg, the amount of isocyanate used is 50 kg, the amount of catalyst used is 1.5 kg, the amount of tackifying resin used is 10 kg, the amount of viscosity stabilizer used is 5 kg, the amount of pentaerythritol diacrylate used is 1 kg, the amount of auxiliary agent used is 5 kg, and the amount of coupling agent used is 3 kg.

[0028] Example 3 The difference between Example 3 and Example 1 is that the amount of polyether polyol used in the raw material of the moisture-curing reactive polyurethane hot melt adhesive for luggage is 20 kg, the amount of polyester polyol used is 40 kg, the amount of isocyanate used is 20 kg, the amount of catalyst used is 0.5 kg, the amount of tackifying resin used is 20 kg, the amount of viscosity stabilizer used is 3 kg, the amount of pentaerythritol diacrylate used is 3 kg, the amount of auxiliary agent used is 10 kg, and the amount of coupling agent used is 5 kg.

[0029] Example 4 The difference between Example 4 and Example 1 is that the coupling agent in the luggage moisture-curing reactive polyurethane hot melt adhesive raw material is γ-(2,3-epoxypropoxy)propyltrimethylsilane.

[0030] Example 5 The difference between Example 5 and Example 1 is that the coupling agent in the luggage moisture-curing reactive polyurethane hot melt adhesive raw material is γ-(methacryloyloxy)propyltrimethylsilane.

[0031] Example 6 The difference between Example 6 and Example 1 is that the viscosity stabilizer in the raw material of the moisture-curing reactive polyurethane hot melt adhesive for luggage is polyphosphoric acid, wherein the polyphosphoric acid is purchased from Nantong Runfeng Petrochemical Co., Ltd. Runfeng brand 8017-16-1.

[0032] Example 7 The difference between Example 7 and Example 6 is that the tackifying resin in the raw material of the moisture-curing reactive polyurethane hot melt adhesive for luggage is petroleum resin, wherein the petroleum resin is C5 petroleum resin.

[0033] Example 8 The difference between Example 8 and Example 6 is that the tackifying resin in the raw material of the moisture-curing reactive polyurethane hot melt adhesive for luggage is disproportionate rosin resin, wherein the acid value of the disproportionate rosin resin is 156 mgKOH / g and the softening point is 76°C.

[0034] Example 9 The difference between Example 9 and Example 8 is that the disproportionate rosin resin in the luggage moisture-curing reactive polyurethane hot melt adhesive raw material is modified by volume expansion.

[0035] The preparation method of the moisture-curing reactive polyurethane hot melt adhesive for luggage comprises the following specific steps: S1: Grind the disproportionated rosin into powder in advance, heat and melt it under the protection of nitrogen, then add a modified catalyst and a polyol, wherein the catalyst is zinc oxide, the polyol is pentaerythritol, and the mass ratio of the disproportionated rosin, the modified catalyst and the polyol is 1:0.1:1, heat to 240°C for reaction, and continuously measure the acid value during the reaction until the acid value remains constant to obtain a modified disproportionated rosin resin.

[0036] S2: Mix polyether polyol, polyester polyol, modified disproportionated rosin resin, viscosity stabilizer, pentaerythritol diacrylate and additives, melt mix at 100°C, vacuum dehydrate, then add isocyanate under the protection of nitrogen and heat to 120°C for reaction, finally add catalyst and coupling agent and react at 120°C for 2h, the coupling agent blocking rate reaches 15%, and the luggage moisture-curing reactive polyurethane hot melt adhesive is obtained.

[0037] Example 10 The difference between Example 10 and Example 8 is that the polyol used in the modification process of the disproportionate rosin resin in the urethane hot melt adhesive raw material is glycerol.

[0038] The preparation method of the moisture-curing reactive polyurethane hot melt adhesive for luggage comprises the following specific steps: S1: Grind the disproportionated rosin into powder in advance, heat and melt it under the protection of nitrogen, then add a modified catalyst and a polyol, wherein the catalyst is zinc oxide, the polyol is glycerol, and the mass ratio of the disproportionated rosin, the modified catalyst and the polyol is 1:0.1:1, heat to 240°C for reaction, and continuously measure the acid value during the reaction until the acid value remains constant to obtain a modified disproportionated rosin resin.

[0039] S2: Mix polyether polyol, polyester polyol, modified disproportionated rosin resin, viscosity stabilizer, pentaerythritol diacrylate and additives, melt mix at 100°C, vacuum dehydrate, then add isocyanate under the protection of nitrogen and heat to 120°C for reaction, finally add catalyst and coupling agent and react at 120°C for 2h, the coupling agent blocking rate reaches 15%, and the luggage moisture-curing reactive polyurethane hot melt adhesive is obtained.

[0040] Comparative Example Comparative Example 1 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 luggage.

[0041] The preparation method of the moisture-curing reactive polyurethane hot melt adhesive for luggage comprises the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer and auxiliary agent, melting and mixing at 100°C, vacuum dehydration, then adding isocyanate under the protection of nitrogen and heating to 120°C for reaction, finally adding catalyst and coupling agent and reacting at 120°C for 2h, wherein the end-capping rate of the coupling agent reaches 15%, and the moisture-curing reactive polyurethane hot melt adhesive for luggage is obtained.

[0042] Comparative Example 2 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 moisture-curing reactive polyurethane hot melt adhesive for luggage.

[0043] The preparation method of the moisture-curing reactive polyurethane hot melt adhesive for luggage comprises the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin and auxiliary agent, melting and mixing at 100°C, vacuum dehydrating, then adding isocyanate under the protection of nitrogen and heating to 120°C for reaction, finally adding catalyst and coupling agent and reacting at 120°C for 2h, wherein the end-capping rate of the coupling agent reaches 15%, and the moisture-curing reactive polyurethane hot melt adhesive for luggage is obtained.

[0044] Performance testing According to the luggage moisture-curing reactive polyurethane hot melt adhesive provided in Examples 1-10 and Comparative Examples 1-2 of the present application, the following performance tests were performed, and the specific test results are shown in Table 1.

[0045] Detection Methods 1. Adhesive properties With reference to the standard FZ / T01085-2009 "Test Method for Peeling Strength of Hot-Melt Adhesive Lining", the initial peel strength and final peel strength of the moisture-curing reactive polyurethane hot-melt adhesive for luggage prepared in this application were tested. The preparation method of the bonding sample is as follows: the sample is heated to 80°C, coated on the luggage bionic fabric with a stainless steel round mesh with a pore size of 0.45μm, and laminated with the same material fabric by a pressing machine, and finally placed in a constant temperature and humidity environment of 20°C and 80% humidity, and taken out after 10 minutes and 48 hours to test the peel strength, and the test results of 10 minutes and 48 hours are defined as the initial peel strength and the final peel strength, respectively.

[0046] Table 1: Performance test results data table It can be seen from the performance test results that the luggage moisture-curing reactive polyurethane hot melt adhesive prepared in the present application has good initial adhesion and later adhesion due to the synergistic effect of various components.

[0047] By comparing Example 6 with Example 1, it can be seen that the use of different viscosity stabilizers has different promoting effects on the bonding performance of the polyurethane hot melt adhesive. From the performance test results, it can be seen that the polyurethane hot melt adhesive prepared in Example 6 has better comprehensive performance.

[0048] It can be seen from Examples 9-10 that by modifying the disproportionate rosin resin, it can be seen from the performance test results that the bonding strength of the polyurethane hot melt adhesive is significantly increased, and the later bonding force is also enhanced.

[0049] By comparing Comparative Examples 1-2 with Example 1, it can be seen that Comparative Example 1 does not use pentaerythritol diacrylate, and Comparative Example 2 does not use pentaerythritol diacrylate and viscosity stabilizer. From the performance test results, it can be seen that the bonding strength of the polyurethane hot melt adhesive will decrease, further indicating that the initial adhesion and later adhesion of the hot melt adhesive formed by a single polyurethane prepolymer are both low, and cannot meet the requirements of the luggage field.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A moisture-curing reactive polyurethane hot melt adhesive for luggage, characterized in that: The invention 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 catalyst, 10-20 parts of tackifying resin, 3-5 parts of viscosity stabilizer, 1-3 parts of pentaerythritol diacrylate, 5-10 parts of auxiliary agent and 3-5 parts of coupling agent.

2. The moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 1, characterized in that: The viscosity stabilizer is polyphosphoric acid.

3. The moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 1, characterized in that: The coupling agent is one of 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethylsilane and γ-(methacryloyloxy)propyltrimethylsilane.

4. The moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 3, characterized in that: The coupling agent capping rate ranges from 13 to 17%.

5. The moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 1, characterized in that: The auxiliary agents include antioxidants and leveling agents.

6. The moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 1, characterized in that: The tackifying resin is one of polyacrylic acid resin, petroleum resin and disproportionated rosin resin.

7. The moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 6, characterized in that: The disproportionated rosin resin is subjected to volume expansion and modification, and the volume expansion and modification method comprises the following specific steps: The disproportionated rosin is heated and melted in advance under an inert gas, and then a modified catalyst and a polyol are added to form a reaction solution. The reaction solution is heated to 230-250°C for reaction, and stirred evenly until the acid value of the reaction solution remains unchanged. The reaction solution is cooled to obtain a modified disproportionated rosin resin.

8. A method for preparing the moisture-curing reactive polyurethane hot melt adhesive for luggage as claimed in any one of claims 1 to 7, characterized in that: The method comprises the following specific steps: mixing polyether polyol, polyester polyol, tackifying resin, viscosity stabilizer, pentaerythritol diacrylate and auxiliary agent, melting and mixing at 80-120 DEG C, vacuum dehydrating, then adding isocyanate under the protection of nitrogen for heating reaction, and finally adding catalyst and coupling agent for heat preservation reaction to obtain luggage moisture-curing reactive polyurethane hot melt adhesive.

9. The method for preparing the moisture-curing reactive polyurethane hot melt adhesive for luggage according to claim 8, characterized in that: The reaction temperature is 100-120°C.

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