A two-component polyurethane adhesive, its preparation method and application

Abstract

The present invention discloses a two-component polyurethane adhesive and its preparation method and application, belonging to the technical field of adhesives. The polyurethane adhesive of the present invention comprises component A and component B. Component A is a polyurethane prepolymer, which is prepared by reacting 40-80 parts by weight of polyol, 30-50 parts by weight of diisocyanate and 0.005-0.01 parts by weight of catalyst as raw materials; Component B is composed of a chain extender and a crosslinking agent with a mass ratio of 7-15:1-5; The crosslinking agent is at least one of trimethylolpropane and glycerol. The polyurethane adhesive of the present invention is solvent-free and environmentally friendly; it does not require moisture curing, can cure itself to form a tight structure, and inhibits the generation of bubbles; without fillers, it can have the advantages of high bonding performance and high temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly relates to a two-component polyurethane adhesive and its preparation method and application. Background Art

[0002] Polyurethane has good adhesion to many materials and is used in many fields, such as the automotive field, the wood field, the shoe-making field, the packaging field, the construction field, the ink field, the rubber field, etc. In rubber bonding, polyisocyanate adhesives or rubber-modified polyurethane adhesives are mostly used, and most of them contain solvents. Relying on the solvents, the rubber surface shows a swelling effect, and small-molecule polyisocyanates penetrate into the inner layer of the rubber and react chemically with the active hydrogen existing in the rubber to form chemical covalent bonds. In addition, stronger intermolecular force ureido groups and biurets can be formed through moisture. At the same time, when the adhesive is cured by heating, isocyanates may undergo self-polymerization to form a firm cross-linked structure, forming a stronger interpenetrating cross-linked network structure with the cross-linked network structure of rubber molecules, so that the adhesive layer and the rubber have excellent bonding effects. However, due to the use of solvents and the need for moisture curing, there are tiny bubbles in the joints of rubber bonded to rubber. The volatilization of solvents will produce a large amount of VOCs, which does not conform to the theme of current green chemical production. At the same time, high-temperature heating may reduce the performance of rubber products, all of which will reduce the adhesive shear strength of polyurethane adhesives, and it is necessary to add high-temperature resistant fillers and / or additives to reduce the influence of high temperature on polyurethane adhesives. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a two-component polyurethane adhesive without fillers, without solvent addition, and with high temperature resistance, and its preparation method and application.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] In the first aspect, the present invention provides a two-component polyurethane adhesive, including component A and component B;

[0006] Component A is a polyurethane prepolymer, and the polyurethane prepolymer is prepared by reacting 40-80 parts by weight of polyol, 30-50 parts by weight of diisocyanate, and 0.005-0.01 parts by weight of a catalyst as raw materials;

[0007] Component B is composed of a chain extender and a cross-linking agent with a mass ratio of 7-15:1-5; the cross-linking agent is at least one of trimethylolpropane and glycerol.

[0008] The present invention uses a highly polar polyurethane prepolymer as the main body, which is mainly prepared by reacting polyols, diisocyanates and catalysts as raw materials. A large number of isocyanate groups are contained in the structure of the polyurethane prepolymer. The polyurethane prepolymer can adjust the polarity and cohesive strength of the polyurethane adhesive, thereby adjusting the adhesion performance and high-temperature resistance of the polyurethane. The present invention introduces a crosslinking agent and a chain extender. The hydroxyl groups in the crosslinking agent and the chain extender react with the isocyanate groups in the polyurethane prepolymer to form a network structure with a higher crosslinking density, greatly enhancing the cohesive strength and high-temperature resistance of the adhesive. In addition, the mass ratio of the crosslinking agent to the chain extender affects the performance of the polyurethane adhesive. If the mass ratio of the crosslinking agent to the chain extender is too small, the viscosity of the product increases, and the bonding performance and high-temperature resistance decrease significantly. If the mass ratio of the crosslinking agent to the chain extender is too large, although the high-temperature resistance of the product will increase, the viscosity of the product will decrease significantly, resulting in low bonding strength of the product.

[0009] The inventors found that when the crosslinking agent is trimethylolpropane and / or glycerol, the crosslinking agent effectively reduces the viscosity of the polyurethane adhesive, making it easier to apply the glue; at the same time, it is beneficial to improve the high-temperature resistance of the polyurethane adhesive. Therefore, the present invention preferably has a mass ratio of trimethylolpropane to glycerol of 1-3:3:1.

[0010] As a preferred embodiment of the polyurethane adhesive of the present invention, the polyol is at least one of polycaprolactone diol, polypropylene carbonate diol, polytetrahydrofuran ether diol, polyester diol, ethylene glycol-modified hexanediol adipate diol, and hexanediol adipate diol.

[0011] Preferably, the polyester diol is a branched polyester diol with a benzene ring, specifically XCP-2000IPS of Asahi Kasei Chemicals (Suzhou) Co., Ltd.; preferably, the ethylene glycol-modified hexanediol adipate diol is HDPOL-2420E of Shanghai Huide Technology Co., Ltd.

[0012] As a preferred embodiment of the polyurethane adhesive of the present invention, the polyol is hexanediol adipate diol and polyester diol; the mass ratio of hexanediol adipate diol to polyester diol is 7-12.

[0013] When the polyol is the above-mentioned substance, the polyurethane adhesive can have better high-temperature resistance.

[0014] As a preferred embodiment of the polyurethane adhesive of the present invention, the number-average molecular weight of the polyol is 1000-3000; preferably, the number-average molecular weight of the polyol is 1500-2500. When the number-average molecular weight of the polyol is 1000-3000, the polyurethane adhesive can have better high-temperature resistance.

[0015] As a preferred embodiment of the polyurethane adhesive of the present invention, the diisocyanate is at least one of diphenylmethane diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate. The diisocyanate can provide the polyurethane adhesive with good room-temperature bonding performance and high-temperature resistance performance.

[0016] As a preferred embodiment of the polyurethane adhesive of the present invention, the chain extender is at least one of 1,4-butanediol, 1,2-butanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, resorcinol, 1,6-hexanediol, triethylenediamine, ethylene glycol, and polyethylene glycol. When the chain extender is the above substances, the polyurethane adhesive can have better high-temperature resistance performance.

[0017] As a preferred embodiment of the polyurethane adhesive of the present invention, the catalyst is at least one of stannous octoate, dibutyltin dilaurate, and organometallic catalysts.

[0018] Second, the present invention provides a preparation method of the above polyurethane adhesive, including the following steps:

[0019] Prepare component A: Place the polyol, diisocyanate, and catalyst in a reactor, and react at 60-90 °C for 2-6 h to obtain component A;

[0020] Prepare component B: Mix the chain extender and crosslinking agent evenly to obtain component B;

[0021] Prepare the polyurethane adhesive: Mix component A and component B evenly at room temperature to obtain the polyurethane adhesive.

[0022] Preferably, in the preparation of component A, the reaction temperature is 75-85 °C, and the reaction time is 2.5-4 h. When the reaction temperature is 75-85 °C and the reaction time is 2.5-4 h, the prepared polyurethane prepolymer has better stability, which is beneficial to the subsequent reaction.

[0023] According to an embodiment of the present invention, the polyurethane adhesive can be stored at room temperature.

[0024] According to an embodiment of the present invention, the polyurethane adhesive needs to be used up within 30-40 minutes.

[0025] Fourth, the present invention provides an application of the above polyurethane adhesive in rubber bonding.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The polyurethane adhesive of the present invention is solvent-free and environmentally friendly; it does not require moisture curing, can cure itself to form a tight structure, and inhibits the generation of bubbles; without fillers, it can have the advantages of high bonding performance and high temperature resistance.

[0028] (2) The polyurethane adhesive of the present invention has a long storage time and a simple preparation method.

[0029] (3) The polyurethane adhesive of the present invention is suitable for bonding rubber products, especially in the field of non-pneumatic tires. Description of the Drawings

[0030] Figure 1 It is a graph of the static shear strength of the polyurethane adhesives obtained in Examples 1-9 and Comparative Examples 1-3 at 90 °C. Detailed Embodiments

[0031] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings.

[0032] In the embodiments, the experimental methods used are all conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0033] Now, the raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials:

[0034] HDPOL-2420E: Polyhexamethylene adipate glycol modified with ethylene glycol, purchased from Shanghai Huide Technology Co., Ltd.;

[0035] XCP-2000IPS: Branched polyester diol with benzene ring, purchased from Asahi Kasei Chemicals (Suzhou) Co., Ltd.

[0036] Example 1

[0037] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method.

[0038] (1) Preparation of Component A

[0039] Put 50 parts by weight of polyhexamethylene adipate glycol (molecular weight 2000, hydroxyl functionality 2) into a reaction kettle, dehydrate at 110 °C for 2 h, then add 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate and 0.005 parts by weight of stannous octoate, and stir at a constant temperature of 75 °C for 1.5 hours to obtain Component A;

[0040] (2) Preparation of Component B

[0041] Mix 1.8 parts by weight of glycerol, 7.5 parts by weight of 1,2-butanediol, and 10 parts by weight of polyethylene glycol (molecular weight 400) evenly at 50 °C, then evacuate to remove bubbles to obtain Component B;

[0042] (3) Prepare the polyurethane adhesive

[0043] Mix the obtained Component A and Component B evenly to obtain the polyurethane adhesive.

[0044] Example 2

[0045] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method.

[0046] (1) Prepare Component A

[0047] Put 45 parts by weight of polyhexamethylene adipate glycol (molecular weight 2000, hydroxyl functionality 2) and 5 parts by weight of XCP-2000IPS into a reaction kettle, dehydrate at 110 °C for 2 h, then add 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate, and stir constantly at 75 °C for 1.5 hours to obtain Component A;

[0048] (2) Prepare Component B

[0049] Mix 1.8 parts by weight of glycerol, 7.5 parts by weight of 1,2-butanediol, and 10 parts by weight of polyethylene glycol (molecular weight 400) evenly at 50 °C, then evacuate to remove bubbles to obtain Component B;

[0050] (3) Prepare the polyurethane adhesive

[0051] Mix the obtained Component A and Component B evenly to obtain the polyurethane adhesive.

[0052] Example 3

[0053] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method.

[0054] (1) Prepare Component A

[0055] Put 45 parts by weight of polytetrahydrofuran ether glycol (molecular weight 2000, hydroxyl functionality 2) and 5 parts by weight of XCP-2000IPS into a reaction kettle, dehydrate at 110 °C for 2 h, then add 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate, and stir constantly at 75 °C for 1.5 hours to obtain Component A;

[0056] (2) Prepare Component B

[0057] Mix 1.8 parts by weight of glycerol, 7.5 parts by weight of 1,2-butanediol, and 10 parts by weight of polyethylene glycol (molecular weight 400) evenly at 50 °C, then evacuate to remove bubbles to obtain Component B;

[0058] (3) Prepare the polyurethane adhesive

[0059] Mix the obtained Component A and Component B evenly to obtain the polyurethane adhesive.

[0060] Example 4

[0061] This example is used to illustrate the polyurethane adhesive and its preparation method provided by the present invention.

[0062] (1) Prepare Component A

[0063] Put 45 parts by weight of HDPOL-2420E (molecular weight 2000, hydroxyl functionality 2) and 5 parts by weight of XCP-2000IPS into a reaction kettle, dehydrate at 110 °C for 2 h, then add 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate, and stir constantly at 75 °C for 1.5 hours to obtain Component A;

[0064] (2) Prepare Component B

[0065] Mix 1.8 parts by weight of glycerol, 7.5 parts by weight of 1,2-butanediol, and 10 parts by weight of polyethylene glycol (molecular weight 400) evenly at 50 °C, then evacuate to remove bubbles to obtain Component B;

[0066] (3) Prepare the polyurethane adhesive

[0067] Mix the obtained Component A and Component B evenly to obtain the polyurethane adhesive.

[0068] Example 5

[0069] This example is used to illustrate the polyurethane adhesive and its preparation method provided by the present invention.

[0070] (1) Prepare Component A

[0071] Put 41 parts by weight of polyhexamethylene adipate glycol (molecular weight about 1000, hydroxyl functionality 2) into a reaction kettle, dehydrate at 110 °C for 2 h, then add 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate, and stir constantly at 75 °C for 1.5 hours to obtain Component A;

[0072] (2) Prepare Component B

[0073] Mix 1.8 parts by weight of glycerol, 7.5 parts by weight of 1,2-butanediol, and 10 parts by weight of polyethylene glycol (molecular weight 400) evenly at 50°C, and then evacuate to remove air bubbles to obtain Component B;

[0074] (3) Prepare the polyurethane adhesive

[0075] Mix the obtained Component A and Component B evenly to obtain the polyurethane adhesive.

[0076] Example 6

[0077] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method. The difference between this example and Example 2 is only that: the mass ratio of polyhexamethylene adipate diol and CP-2000IPS is 7.

[0078] Example 7

[0079] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method. The difference between this example and Example 2 is only that: the mass ratio of polyhexamethylene adipate diol and CP-2000IPS is 12.

[0080] Example 8

[0081] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method. The difference between this example and Example 2 is only that: in the preparation of Component B, 1.8 parts by weight of trimethylolpropane is used instead of 1.8 parts by weight of glycerol.

[0082] Example 9

[0083] This example is used to illustrate the polyurethane adhesive provided by the present invention and its preparation method. The difference between this example and Example 2 is only that: the steps for preparing Component B are: mix 6 parts by weight of glycerol and 10 parts by weight of polyethylene glycol (molecular weight 400) evenly at 50°C, and then evacuate to remove air bubbles to obtain Component B.

[0084] Comparative Example 1

[0085] Prepare the polyurethane adhesive according to the method of Example 2, except that 7.5 parts by weight of triethylenediamine is used instead of 7.5 parts by weight of 1,2-butanediol.

[0086] Comparative Example 2

[0087] Prepare the polyurethane adhesive according to the method of Example 2, except that 1.8 parts by weight of castor oil is used instead of 1.8 parts by weight of glycerol.

[0088] Comparative Example 3

[0089] The polyurethane adhesive was prepared according to the method of Example 2, except that 7.5 parts by weight of trifunctional polyetheramine was used instead of 7.5 parts by weight of 1,2-butanediol.

[0090] Test Example 1

[0091] Performance Test of Polyurethane Adhesive

[0092] (1) High-temperature resistance:

[0093] (2) Bonding performance: The polyurethane adhesives obtained in Examples 1-9 and Comparative Examples 1-3 were applied to rubber sheets with a joint of 12.5*25 mm. After applying a pressure of 0.1 MPa to fix for 6 h, they were left at room temperature for 3 days, and then treated in an oven at 60 °C for 6 h. The obtained samples were placed in an environment at 90 °C to test the static shear strength and dynamic shear fatigue effect.

[0094] The test results are shown in Table 1 and Figure 1 as follows.

[0095] Table 1

[0096]

[0097]

[0098] It can be seen from Table 1 that the polyurethane adhesive of the present invention has excellent bonding performance and high-temperature resistance.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A two-component polyurethane adhesive, characterized in that, It consists of Component A and Component B; Component A is a polyurethane prepolymer, which is prepared by reacting 40 - 80 parts by weight of polyol, 30 - 50 parts by weight of diisocyanate, and 0.005 - 0.01 parts by weight of catalyst as raw materials; Component B consists of a chain extender and a crosslinking agent with a mass ratio of 7 - 15:1 - 5; the crosslinking agent is at least one of trimethylolpropane and glycerol; The two-component polyurethane adhesive does not contain fillers and solvents; The polyol is at least one of polytetrahydrofuran ether diol, polyester diol XCP-2000IPS, polyhexamethylene adipate diol, and ethylene glycol-modified polyhexamethylene adipate diol HDPOL-2420E; The chain extender is 1,2-butanediol and polyethylene glycol.

2. The polyurethane adhesive according to claim 1, wherein The polyol is polyhexamethylene adipate diol and polyester diol XCP-2000IPS; the mass ratio of polyhexamethylene adipate diol and polyester diol XCP-2000IPS is 7 - 12.

3. The polyurethane adhesive according to claim 1, wherein The number-average molecular weight of the polyol is 1000 - 3000.

4. The polyurethane adhesive according to claim 3, wherein The number-average molecular weight of the polyol is 1500 - 2500.

5. The polyurethane adhesive according to claim 1, characterized in that, The diisocyanate is at least one of diphenylmethane diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl polyisocyanate.

6. The polyurethane adhesive according to claim 1, wherein The catalyst is at least one of stannous octoate and dibutyltin dilaurate.

7. The polyurethane adhesive according to claim 1, characterized in that, The catalyst is an organometallic catalyst.

8. A method for preparing the polyurethane adhesive according to any one of claims 1-7, characterized in that, It includes the following steps: Preparing Component A: Placing the polyol, diisocyanate, and catalyst in a reactor and reacting at 60 - 90°C for 1 - 6 h to obtain Component A; Preparing Component B: Mixing the chain extender and the crosslinking agent evenly to obtain Component B; Preparing the polyurethane adhesive: Mixing Component A and Component B evenly at room temperature to obtain the polyurethane adhesive.

9. The preparation method according to claim 8, characterized in that, In the preparation of Component A, the reaction temperature is 75 - 85°C, and the reaction time is 1.5 - 4 h.

10. The application of the polyurethane adhesive according to any one of claims 1 - 7 in rubber bonding.

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