阅读说明：本技术 一种改性聚硫醇、其制备方法及应用 (Modified polythiol, and preparation method and application thereof ) 是由 梁万根 张超 崔卫华 费潇瑶 宋吻吻 靖培培 于 2019-11-25 设计创作，主要内容包括：本发明提供了一种改性聚硫醇的制备方法,包括：S)将硫醇类化合物、端环氧基有机硅树脂与有机溶剂混合进行回流反应,得到改性聚硫醇。与现有技术相比,本发明以端环氧基有机硅树脂为改性剂,将其开环与硫醇类化合物反应,使有机硅树脂链接到硫醇类化合物上,从而使得到的改性聚硫醇兼具有机与无机的结构及性能,具有较高的耐高温性、耐候性、耐水性和耐腐蚀性,且长期在潮湿环境下粘结性能不会发生变化。(The invention provides a preparation method of modified polythiol, which comprises the following steps: s) mixing a thiol compound, epoxy-terminated organic silicon resin and an organic solvent for reflux reaction to obtain the modified polythiol. Compared with the prior art, the epoxy-terminated organic silicon resin is used as a modifier, and the ring opening of the epoxy-terminated organic silicon resin is reacted with the thiol compound to enable the organic silicon resin to be linked to the thiol compound, so that the obtained modified polythiol has organic and inorganic structures and performances, has higher high temperature resistance, weather resistance, water resistance and corrosion resistance, and can not change in bonding performance under a humid environment for a long time.)

1. A method for preparing a modified polythiol, comprising:

s) mixing a thiol compound, epoxy-terminated organic silicon resin and an organic solvent for reflux reaction to obtain the modified polythiol.

2. The preparation method according to claim 1, wherein the step S) is specifically:

mixing a thiol compound with an organic solvent, heating and stirring; then, epoxy-terminated organic silicon resin is dripped, and after the dripping is finished, reflux reaction is carried out to obtain the modified polythiol.

3. The preparation method according to claim 2, wherein the temperature of the system when the epoxy-terminated silicone resin is dripped is 45 ℃ to 70 ℃; the time for dripping the epoxy-terminated organic silicon resin is 1-4 h; the temperature of the reflux reaction is 60-80 ℃; the time of the reflux reaction is 1-3 h.

4. The preparation method according to claim 2, wherein the rotation speed of the heating and stirring is 60 to 100 r/min; the reflux reaction is carried out under the condition of stirring, and the rotating speed of stirring is 200-300 r/min.

5. The process according to claim 1, wherein the thiol compound is selected from the group consisting of 2, 3-dithio (2-mercapto) -1-propanethiol, pentaerythritol tetrakis (3-mercaptopropionate), 1-propanethiol, 1, 2-propanethiol, 1, 3-propanedithiol, 1, 6-hexanedithiol, 2-dimethylpropane-1, 3-dithiol, 2, 3-dimercapto-1-propanol (2-mercaptoacetate), 2-bis (mercaptomethyl) 1, 3-propanethiol, 2, 3-dimercapto-1-propanol (3-mercaptoacetate), 2, 3-dimercapto-1-propanol (2-mercaptoacetate), and mixtures thereof, One or more of trimethylolpropane bis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptoacetate), trimethylolethane tris (3-mercaptoacetate), pentaerythritol tetrakis (2-mercaptoacetate), 1,3, 3-tetrakis (mercaptomethylthio) propane, 5, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane, 4, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane, and 4, 8-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane;

the epoxy-terminated silicone resin is represented by the formula (I):

wherein R is₁、R₂、R₃Each independently selected from C1-C10 alkyl; n is an integer of 1 to 4; m is an integer of 1-4;

the organic solvent is selected from alcohol solvents.

6. The production method according to claim 1, wherein the mass ratio of the thiol compound to the epoxy-terminated silicone resin is (60 to 96): (0.05-40); the mass ratio of the thiol compound to the organic solvent is (60-96): (50-120).

7. The process according to claim 1, wherein the reflux reaction is followed by refining by vacuum distillation to obtain the modified polythiol.

8. The production method according to claim 7, wherein the temperature of the vacuum distillation refining is 55 ℃ to 90 ℃; the time is 0.5-2 h.

9. A modified polythiol characterized by being formed from a thiol compound and an epoxy-terminated silicone resin.

10. Use of a modified polythiol prepared according to any of claims 1 to 8 as a curing agent for epoxy resins.

Technical Field

The invention belongs to the technical field of adhesives, and particularly relates to a modified polythiol, and a preparation method and application thereof.

Background

Epoxy resin adhesives, phenolic resins and unsaturated polyester resins are called three general thermosetting resins, and are the varieties with the largest use amount and the widest application range in the thermosetting resins. The epoxy resin adhesive has many excellent performances because of containing unique epoxy groups, active groups such as hydroxyl groups, ether bonds and the like and polar groups.

The epoxy resin adhesive mainly comprises two parts, namely epoxy resin and a curing agent. The epoxy resin is a thermoplastic linear compound, cannot be directly used as an adhesive, and only has practical application value because a curing agent is added and a curing crosslinking reaction is carried out under certain conditions to generate an insoluble (molten) network structure. Thus, the curing agent is an essential component of the epoxy adhesive.

Curing agents for epoxy resins can be broadly classified into two categories: (1) the reactive curing agent can be added with EP molecules, and is crosslinked into a three-dimensional network structure through the process of stepwise polymerization reaction, generally contains active hydrogen atoms, and is accompanied with the transfer of the hydrogen atoms in the reaction process, such as poly-primary amine, poly-carboxylic acid, poly-mercaptan, poly-phenol and the like; (2) the catalytic curing agent can initiate the curing reaction of epoxy group in resin according to the cationic or anionic polymerization process, such as tertiary amine, imidazole, boron trifluoride complex, etc. Polythiols are typical polythiols, the terminal of which contains more than 2 mercapto groups, and a curing agent capable of rapidly curing with epoxy resins at room temperature for 5 min. Compared with other curing agents such as amines and acid anhydrides, the polythiol curing agent has the characteristics of low-temperature rapid curing and the like, can meet the requirements of certain areas with lower outdoor temperature in winter, effectively improves the efficiency of engineering construction, simultaneously has sulfur-containing flexible two ends and higher refractive index, and has very high application value in the aspects of increasing the toughness and transparency of resin.

However, because of the structural limitation of polythiol, the polythiol has poor high temperature resistance and weather resistance, poor adhesive property and easy cracking during long-term use in humid and corrosive environments, and thus the application field and the service cycle of the polythiol are influenced.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a modified polythiol, a preparation method and an application thereof, wherein the modified polythiol has high temperature resistance, weather resistance, water resistance and corrosion resistance.

The invention provides a preparation method of modified polythiol, which comprises the following steps:

s) mixing a thiol compound, epoxy-terminated organic silicon resin and an organic solvent for reflux reaction to obtain the modified polythiol.

Preferably, the step S) is specifically:

mixing a thiol compound with an organic solvent, heating and stirring; then, epoxy-terminated organic silicon resin is dripped, and after the dripping is finished, reflux reaction is carried out to obtain the modified polythiol.

Preferably, the temperature of the system is 45-70 ℃ when the epoxy-terminated silicone resin is dripped; the time for dripping the epoxy-terminated organic silicon resin is 1-4 h; the temperature of the reflux reaction is 60-80 ℃; the time of the reflux reaction is 1-3 h.

Preferably, the rotating speed of the heating and stirring is 60-100 r/min; the reflux reaction is carried out under the condition of stirring, and the rotating speed of stirring is 200-300 r/min.

Preferably, the thiol compound is selected from the group consisting of 2, 3-dithio (2-mercapto) -1-propanethiol, pentaerythritol tetrakis (3-mercaptopropionate), 1-propanedithiol, 1, 2-propanedithiol, 1, 3-propanedithiol, 1, 6-hexanedithiol, 2-dimethylpropane-1, 3-dithiol, 2, 3-dimercapto-1-propanol (2-mercaptoacetate), 2-bis (mercaptomethyl) 1, 3-propanedithiol, 2, 3-dimercapto-1-propanol (3-mercaptoacetate), 2, 3-dimercapto-1-propanol (2-mercaptoacetate), trimethylolpropane bis (3-mercaptopropionate), One or more of trimethylolpropane tris (3-mercaptoacetate), trimethylolethane tris (3-mercaptoacetate), pentaerythritol tetrakis (2-mercaptoacetate), 1,3, 3-tetrakis (mercaptomethylthio) propane, 5, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane, 4, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane, and 4, 8-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane;

the epoxy-terminated silicone resin is represented by the formula (I):

wherein R is₁、R₂、R₃Each independently selected from C1-C10 alkyl; n is an integer of 1 to 4; m is an integer of 1-4;

the organic solvent is selected from alcohol solvents.

Preferably, the mass ratio of the thiol compound to the epoxy-terminated silicone resin is (60-96): (0.05-40); the mass ratio of the thiol compound to the organic solvent is (60-96): (50-120).

Preferably, after the reflux reaction, the modified polythiol is further refined by vacuum distillation to obtain the modified polythiol.

Preferably, the temperature of the vacuum distillation refining is 55-90 ℃; the time is 0.5-2 h.

The invention also provides a modified polythiol which is formed by a thiol compound and an epoxy-terminated organic silicon resin.

The invention also provides application of the modified polythiol as an epoxy resin curing agent.

The invention provides a preparation method of modified polythiol, which comprises the following steps: s) mixing a thiol compound, epoxy-terminated organic silicon resin and an organic solvent for reflux reaction to obtain the modified polythiol. Compared with the prior art, the epoxy-terminated organic silicon resin is used as a modifier, and the ring opening of the epoxy-terminated organic silicon resin is reacted with the thiol compound to enable the organic silicon resin to be linked to the thiol compound, so that the obtained modified polythiol has organic and inorganic structures and performances, has higher high temperature resistance, weather resistance, water resistance and corrosion resistance, and can not change in bonding performance under a humid environment for a long time.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of modified polythiol, which comprises the following steps: s) mixing a thiol compound, epoxy-terminated organic silicon resin and an organic solvent for reflux reaction to obtain the modified polythiol.

In the present invention, the sources of all raw materials are not particularly limited, and they may be commercially available.

The thiol compound is preferably a thiol compound having 2 or more thiol groups at the end, more preferably a thiol compound having 2 to 4 thiol groups at the end, still more preferably 2, 3-dithio (2-thiol) -1-propanethiol, pentaerythritol tetrakis (3-mercaptopropionate), 1-propanethiol, 1, 2-propanethiol, 1, 3-propanethiol, 1, 6-hexanedithiol, 2-dimethylpropane-1, 3-dithiol, 2, 3-dimercapto-1-propanol (2-mercaptoacetate), 2-bis (mercaptomethyl) 1, 3-propanethiol, 2, 3-dimercapto-1-propanol (3-mercaptoacetate), 2, 3-dimercapto-1-propanol (2-mercaptoacetate), trimethylolpropane bis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptoacetate), trimethylolethane tris (3-mercaptoacetate), pentaerythritol tetrakis (2-mercaptoacetate), 1,3, 3-tetrakis (mercaptomethylthio) propane, one or more of 5, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane, 4, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane, and 4, 8-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithiaundecane.

The epoxy-terminated silicone resin is preferably represented by the formula (I):

wherein R is₁、R₂、R₃Each independently is a C1-C10 alkyl group, more preferably a C1-C8 alkyl group, still more preferably a C1-C5 alkyl group, still more preferably a C1-C4 alkyl group, still more preferably a C1-C3 alkyl group, and most preferably a C1-C2 alkyl group; n is an integer of 1 to 4, preferably 2 to 3; m is an integer of 1 to 4, preferably 1 to 3, more preferably 1 to 2.

The organic solvent is preferably an alcohol solvent, more preferably ethanol.

Mixing the mercaptan compound, the epoxy-terminated organic silicon resin and the organic solvent, preferably mixing the mercaptan compound and the organic solvent, heating and stirring, and then dropwise adding the epoxy-terminated organic silicon resin; the mass ratio of the thiol compound to the organic solvent is preferably (60-96): (50-120), more preferably (60-90): (50-100), more preferably (62-85): (53-80), most preferably (62-82): (53-78); in some embodiments provided herein, the mass ratio of the thiol compound to the organic solvent is preferably 82: 78, a nitrogen source; in some embodiments provided herein, the mass ratio of the thiol compound to the organic solvent is preferably 75: 69; in other embodiments provided herein, the mass ratio of the thiol compound to the organic solvent is 62: 53; the mass ratio of the thiol compound to the epoxy-terminated silicone resin is preferably (60-96): (0.05-40), more preferably (60-90): (5-30), and more preferably (60-85): (10-20), most preferably (62-82): (14-18); in some embodiments provided herein, the mass ratio of the thiol compound to the epoxy-terminated silicone resin is preferably 82: 18; in some embodiments provided herein, the mass ratio of the thiol compound to the epoxy-terminated silicone resin is preferably 75: 16; in other embodiments provided herein, the mass ratio of the thiol compound to the epoxy-terminated silicone resin is preferably 62: 14; the heating and stirring temperature is preferably 45-65 ℃, more preferably 50-65 ℃, and further preferably 60-65 ℃; the rotating speed of the heating and stirring is preferably 60-300 r/min; in the invention, the epoxy-terminated organic silicon resin is preferably heated and stirred for 10-50 min, more preferably heated and stirred for 20-40 min, and then is preferably heated and stirred for 30min and then is dripped; the temperature of the system is preferably 45-70 ℃, more preferably 50-70 ℃ and further preferably 60-70 ℃ when the epoxy-terminated organic silicon resin is dripped; the time for dripping the epoxy-terminated organic silicon resin is preferably 1-4 h, more preferably 1-3 h, and further preferably 1.5-2.5 h.

After the dropwise addition is finished, carrying out reflux reaction; the temperature of the reflux reaction is preferably 60-80 ℃, and more preferably 65-75 ℃; the time of the reflux reaction is preferably 1 to 3 hours, more preferably 1.5 to 2.5 hours, and still more preferably 2 to 2.5 hours; the reflux reaction is preferably carried out under stirring; the rotating speed of the stirring is preferably 200-350 r/min.

After the reflux reaction is finished, preferably, vacuum distillation refining is also carried out to obtain modified polythiol; the temperature of the vacuum distillation refining is preferably 55-90 ℃, more preferably 55-80 ℃, further preferably 55-70 ℃, and most preferably 55-60 ℃; the time is preferably 0.5-2 h, more preferably 1-1.5 h, and still more preferably 1.2-1.5 h; the vacuum degree of the vacuum distillation refining is preferably-0.08 MPa to-0.095 MPa, and more preferably-0.09 MPa.

The invention takes the epoxy-terminated organic silicon resin as a modifier, and the ring opening of the epoxy-terminated organic silicon resin is reacted with the thiol compound to enable the organic silicon resin to be linked to the thiol compound, so that the obtained modified polythiol has organic and inorganic structures and performances, has higher high temperature resistance, weather resistance, water resistance and corrosion resistance, and can not change in bonding performance under a humid environment for a long time.

The invention also provides a modified polythiol which is formed by a thiol compound and an epoxy-terminated organic silicon resin. The thiol compound and the epoxy-terminated silicone resin are the same as described above, and are not described in detail herein.

The invention also provides application of the modified polythiol prepared by the method as an epoxy resin curing agent.

In order to further illustrate the present invention, the following examples are provided to describe the modified polythiol, its preparation method and application in detail.

The reagents used in the following examples are all commercially available.