Polymer adhesive based on polyurethane and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, and discloses a polyurethane-based polymer adhesive and a preparation method thereof, the adhesive is prepared by taking polyether glycol as a soft segment and a diisocyanate monomer as a hard segment, and carrying out cross-linking polymerization reaction with functional additives and the like under the action of a catalyst, wherein the functional additive is prepared by grafting a macromolecular modifier with a diphenyl ether-cycloheptane alternate connection structure on the surface of vermiculite, and the macromolecular modifier can participate in chain extension polymerization of polyurethane, so that the vermiculite and the polyurethane have good interface bonding property, and by utilizing the lamellar structure of the vermiculite, the functional additive can be used for preparing the polyurethane composite material. According to the present invention, the high-molecular modifier is added to the polyurethane adhesive to form the stable physical barrier layer, such that the dissipation of the adhesive thermal degradation product can be effectively retarded, and the high-molecular modifier structure contains rich rigid rings, silicon-oxygen bonds and ether bonds so as to further enhance the high temperature resistance of the polyurethane adhesive, and further enhance the adhesion property of the polyurethane adhesive.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a polyurethane-based polymer adhesive and its preparation method. Background Technology

[0002] With the upgrading of material connection technology requirements in high-end industries such as aerospace, automobile manufacturing, and electronic packaging, adhesives have evolved from traditional auxiliary materials into key structural components. Currently, adhesives mainly include acrylic adhesives, epoxy resin adhesives, and polyurethane adhesives. Among them, the isocyanate groups in the polyurethane molecular chain form a soft and hard segment phase separation structure with the polyol segments. This unique microphase separation characteristic gives it the ability to "intelligently adjust," enabling continuous control from flexible adhesives to rigid adhesives. In addition, polyurethane adhesives also have good comprehensive properties such as low temperature resistance and media resistance. These advantages enable them to adapt to more complex application environments, thus having a wide range of applications.

[0003] However, polyurethane adhesives have poor high-temperature resistance. When used under continuous high-temperature conditions, the adhesive layer will soften and deform, resulting in a significant decrease in bonding strength and even debonding. This limits the application of polyurethane adhesives.

[0004] Based on this, the present invention provides a polyurethane adhesive that can solve the problems existing in the prior art. Summary of the Invention

[0005] In order to solve the problems mentioned in the background art, the purpose of this invention is to provide a polyurethane-based polymer adhesive and a method for preparing the same.

[0006] The objective of this invention can be achieved through the following technical solutions: A polyurethane-based polymeric adhesive, made from the following raw materials in parts by weight: Polyether diol 60-75 parts, diisocyanate monomer 25-35 parts, catalyst 0.1-0.3 parts, chain extender 1-3 parts, viscosity reducer 80-100 parts, functional additives 2-6 parts, defoamer 0.5-1 part, deionized water 120-150 parts; The functional additive is vermiculite with a surface modified by a polymeric modifier.

[0007] As a further scheme of the present application, the polyether diol is polytetrahydrofuran ether diol with a number average molecular weight of 1000-2000; the diisocyanate monomer is any one of isophorone diisocyanate, toluene diisocyanate or diphenyl methane diisocyanate; the catalyst is any one of dibutyl tin dilaurate, stannous octoate, methyl mercaptan tin, dibutyl tin diacetate or octyl mercaptan tin; the chain extender is dimethylol propanoic acid or dimethylol butanoic acid; and the viscosity reducer is acetone.

[0008] As a further scheme of the present application, the method for preparing the functional additive comprises the following steps: Step one, ultrasonic dispersion of vermiculite in 1,4-dioxane, then adding a surface modifier and p-toluene sulfonic acid to the formed dispersion, after completion of the addition, heating to 90-100℃, and continuing to heat and stir for 6-9h, then stopping heating, cooling and discharging, collecting the solid, washing, vacuum drying to obtain organic modified vermiculite; Step two, adding the organic modified vermiculite into N,N-dimethylformamide, ultrasonic dispersion until uniform, then continuously adding a cycloheptane derivative and an accelerator, after completion of the addition, increasing the temperature to 60-70℃, and continuing to heat and stir for 2-3h, then adding 4,4'-dithioxyphenyl ether, further increasing the temperature to 80-90℃, and continuing to heat and stir for 9-18h, then stopping heating, separating the materials after cooling, washing, vacuum drying to obtain the functional additive.

[0009] As a further scheme of the present application, in step one, the surface modifier is mercaptopropionic acid or 4-mercaptobutyric acid.

[0010] As a further scheme of the present application, in step one, the cycloheptane derivative is prepared by the following method: adding 2-(dicycloheptane dimethyl chlorosilane) and 3-[bis(glycidyl oxymethyl) methoxy]-1,2-propanediol into tetrahydrofuran, mechanically stirring until uniform, increasing the temperature to 60-65℃, adding triethylamine, stirring for 6-9h, evaporating to remove the solvent, collecting the crude product, and purifying to obtain the cycloheptane derivative.

[0011] As a further scheme of the present application, the molar ratio of 2-(dicycloheptane dimethyl chlorosilane) to 3-[bis(glycidyl oxymethyl) methoxy]-1,2-propanediol is 1-2:1.

[0012] As a further scheme of the present application, in step two, the accelerator is triethylamine, tri-n-butylamine, N,N-dimethylcyclohexylamine or N,N-dimethylbenzylamine.

[0013] As a further scheme of the present application, in step two, the mass ratio of the organic modified vermiculite, the cycloheptane derivative and the 4,4'-dithiol diphenyl ether is 1:0.2-0.4:0.1-0.2.

[0014] It should be noted that in the above technical solution, first, p-toluenesulfonic acid is used as a catalyst to catalyze the surface modification of the surface modifier on the vermiculite to obtain vermiculite modified with active thiol functional groups, i.e., organic modified vermiculite. Then, with the thiol groups of the organic modified vermiculite as active initiation sites, the cycloheptane derivative as an intermediate linker, and the 4,4'-dithiol diphenyl ether as a chain extender, the thiol and epoxy groups in the structures of each other continuously undergo ring-opening reaction under the action of the catalyst, thereby grafting a polymer modifier with a diphenyl ether-cycloheptane alternating connection structure on the surface of the vermiculite to obtain a functional additive.

[0015] The cycloheptane derivative is prepared from 2-(dicycloheptane) dimethyl chlorosilane and 3-[bis(glycidyl oxymethyl) methoxy]-1,2-propanediol by substitution reaction of Si-Cl and active hydroxyl groups under the catalytic action of triethylamine.

[0016] A method for making a polyurethane-based polymer adhesive, comprising the following steps: In the first step, the polyether diol is vacuum dehydrated at a temperature of 100-110 DEG C, then the polyether diol, diisocyanate monomer and catalyst are stirred and mixed uniformly at a temperature of 50-60 DEG C, the temperature is adjusted to 70-75 DEG C, after stirring for 2-4 h, the temperature is adjusted again to 40-50 DEG C, the viscosity reducer is added, after stirring uniformly, the chain extender and functional additive are continuously added, and stirring is continued for 2-4 h to obtain a polymerized material; In the second step, deionized water is added to the polymerized material, and stirring and emulsification are carried out for 1-2 h, and the viscosity reducer is removed by evaporation to obtain a polymer emulsion; In the third step, the defoaming agent is added to the polymer emulsion, and stirring is carried out for 10-20 min, and the defoaming agent is allowed to stand to obtain a polymer adhesive.

[0017] The beneficial effects of the present application are: The present application grafts a polymer modifier with a diphenyl ether-cycloheptane alternating connection structure on the surface of vermiculite as a functional additive, and a large number of hydroxyl groups are generated in the ring-opening reaction process, so that the polymer modifier structure contains a large number of active hydroxyl functional groups, which can participate in the chain extension polymerization process of subsequent polyurethane, so that the vermiculite and the polyurethane matrix have good interfacial bonding, and the uniform dispersion of the vermiculite in the polyurethane adhesive is promoted, and a stable physical barrier layer is formed by using the lamellar structure of the vermiculite, which can effectively slow down the escape of adhesive thermal degradation products, thereby improving the high temperature resistance of the adhesive. In addition, the polymer modifier structure also contains a large number of rigid benzene rings and cycloheptane, and high-energy silicon-oxygen bonds, which can improve the stability of the polyurethane molecular chain, thereby further enhancing the high temperature resistance of the polyurethane adhesive. In addition, the polymer modifier structure also contains a large number of ether bonds, which can enhance the bonding performance of the polyurethane adhesive.

[0018] Of course, implementing any product of the present application does not necessarily require achieving all the advantages described above at the same time. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0020] Preparation example Step A, 2.5g vermiculite is ultrasonically dispersed in 1,4-dioxane, then 0.4g mercaptopropionic acid and 0.1g p-toluenesulfonic acid are added to the formed dispersion, after adding, the temperature is raised to 95℃, and the stirring is continued for 8h, then the heating is stopped, the temperature is lowered, and the solid material is collected, washed, and vacuum dried to obtain the organic modified vermiculite; Step B, 0.8g of 2-(dicycloheptane) dimethyl chlorosilane and 1g of 3-[bis(glycidyl oxymethyl) methoxy]-1,2-propanediol are added to tetrahydrofuran, mechanically stirred and mixed uniformly, then the temperature is raised to 65℃, and 0.2g of triethylamine is added, stirred for 8h, then the solvent is evaporated, the crude product is collected, and the purification treatment process is carried out to obtain a cycloheptane derivative; Step C, 1.2 g of organically modified vermiculite was added to N,N-dimethylformamide, after ultrasonic dispersion, 0.4 g of cycloheptane derivative and 0.1 g of triethylamine were added, after the addition, the temperature was increased to 65℃, after 3 h of incubation, 0.2 g of 4,4'-dithioxyphenyl ether was added, and the temperature was further increased to 85℃, and the incubation was continued for 12 h, then the heating was stopped, and after cooling, the material was separated, washed, and vacuum dried to obtain a functional additive.

[0021] Example 1 A polyurethane-based high molecular adhesive was prepared using the following raw materials by weight: Polyether diol 60 parts, diisocyanate monomer 25 parts, catalyst 0.1 part, chain extender 1 part, viscosity reducer 80 parts, functional additive 2 parts, defoamer 0.5 part, deionized water 120 parts; The preparation method of the high molecular adhesive comprises the following steps: First step, vacuum dehydration of polyether diol at 100℃, then stirring and mixing polyether diol, diisocyanate monomer and catalyst uniformly at 50℃, adjusting the temperature to 70℃, stirring for 4 h, then adjusting the temperature to 40℃, adding viscosity reducer, stirring uniformly, then adding chain extender and functional additive, and continuing to stir for 4 h to obtain polymerization material; Second step, adding deionized water to the polymerization material, stirring for 1 h, evaporating to remove the viscosity reducer, and obtaining a polymerization emulsion; Third step, adding defoamer to the polymerization emulsion, stirring for 10 min, and standing for defoaming to obtain the high molecular adhesive.

[0022] The polyether diol has a number average molecular weight of 1000, the diisocyanate monomer is diphenyl methane diisocyanate, the catalyst is dibutyl tin dilaurate, the chain extender is dimethylol propionic acid, the viscosity reducer is acetone, the preparation method of the functional additive is shown in the preparation example, and the defoamer is TEGO Foamex 810.

[0023] Example 2 A polyurethane-based high molecular adhesive was prepared using the following raw materials by weight: Polyether diol 65 parts, diisocyanate monomer 30 parts, catalyst 0.2 parts, chain extender 2 parts, viscosity reducer 90 parts, functional additive 5 parts, defoamer 0.6 parts, deionized water 130 parts; The preparation method of the high molecular adhesive comprises the following steps: The first step, under the temperature condition of 110℃, vacuum dehydration is performed on the polyether diol, then, under the temperature condition of 55℃, the polyether diol, diisocyanate monomer and catalyst are stirred and mixed uniformly, the temperature is adjusted to 75℃, after stirring for 3h, the temperature is adjusted to 50℃ again, the viscosity reducer is added, after stirring uniformly, the chain extender and functional additive are continuously added, and stirring is continued for 3h, to obtain a polymerization material; The second step, deionized water is added to the polymerization material, stirring and emulsification are performed for 2h, the viscosity reducer is removed by evaporation, to obtain a polymerization emulsion; The third step, the defoaming agent is added to the polymerization emulsion, stirring is performed for 15min, and defoaming is performed after standing, to obtain a high molecular adhesive.

[0024] Example 3 A high molecular adhesive based on polyurethane is prepared by using the following raw materials in parts by weight: Polyether diol 75 parts, diisocyanate monomer 35 parts, catalyst 0.3 parts, chain extender 3 parts, viscosity reducer 100 parts, functional additive 6 parts, defoaming agent 1 part, deionized water 150 parts; The preparation method of the high molecular adhesive comprises the following steps: The first step, under the temperature condition of 110℃, vacuum dehydration is performed on the polyether diol, then, under the temperature condition of 60℃, the polyether diol, diisocyanate monomer and catalyst are stirred and mixed uniformly, the temperature is adjusted to 75℃, after stirring for 2h, the temperature is adjusted to 50℃ again, the viscosity reducer is added, after stirring uniformly, the chain extender and functional additive are continuously added, and stirring is continued for 2h, to obtain a polymerization material; The second step, deionized water is added to the polymerization material, stirring and emulsification are performed for 2h, the viscosity reducer is removed by evaporation, to obtain a polymerization emulsion; The third step, the defoaming agent is added to the polymerization emulsion, stirring is performed for 20min, and defoaming is performed after standing, to obtain a high molecular adhesive.

[0025] Comparative Example 1 A high molecular adhesive based on polyurethane, which is different from Example 2 in that the functional additive is replaced by vermiculite, and the rest are the same.

[0026] Comparative Example 2 A high molecular adhesive based on polyurethane, which is different from Example 2 in that the functional additive is removed, and the rest are the same.

[0027] Test Example The polyurethane adhesives prepared by the examples and comparative examples of the present application are uniformly coated on a stainless steel plate, the amount of glue coating is controlled to be 50g / m 2 After coating is completed, it is completely cured to form a glue film, and the following tests are performed: Peeling strength test was carried out according to standard GB / T 2791-1995; The sample was placed in a temperature environment of 100 DEG C, and after 12 hours, the film surface phenomenon was observed, and the high temperature resistance was evaluated; The test results are recorded in the following table: Peeling force (N / mm) film phenomenon Example 1 4.5 No significant phenomenon Example 2 4.6 No significant phenomenon Example 3 4.5 No significant phenomenon Comparative Example 1 4.0 Softening, deformation Comparative Example 2 3.8 Softening, deformation, edge lifting According to the analysis of the test results, the adhesive prepared in the embodiment of the application has good bonding performance and high temperature resistance. After the functional additive is replaced by vermiculite, on the one hand, the crosslinking density is reduced, which affects the cohesive energy, and on the other hand, the content of rigid ring, silicon-oxygen bond and ether bond is reduced, which leads to the significant decrease of the bonding performance and high temperature resistance of the adhesive.

[0028] The principles and implementation manners of the present application are described herein by using specific examples, and the above description of the embodiments is only used to help understand the method of the present application and its core idea, including the best mode, and also enables any person skilled in the art to practice the present application, including manufacturing and using any device or system, and implementing any combined method. It should be noted that, for those skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application. The scope of the patent protection of the present application is defined by the claims, and can include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

[0029] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A polyurethane-based polymeric adhesive, characterized by, The polyurethane adhesive is prepared by using the following raw materials by weight: polyether diol 60-75 parts, diisocyanate monomer 25-35 parts, catalyst 0.1-0.3 parts, chain extender 1-3 parts, viscosity reducer 80-100 parts, functional additive 2-6 parts, defoaming agent 0.5-1 part, deionized water 120-150 parts; The functional additive is vermiculite modified by a high molecular modifier on the surface.

2. The polyurethane-based polymeric adhesive according to claim 1, wherein The polyether diol is polytetrahydrofuran ether diol with a number average molecular weight of 1000-2000; the diisocyanate monomer is any one of isophorone diisocyanate, toluene diisocyanate or diphenyl methane diisocyanate; the catalyst is any one of dibutyl tin dilaurate, stannous octoate, methyl mercaptan tin, dibutyl tin diacetate or octyl mercaptan tin; the chain extender is dimethylol propanoic acid or dimethylol butyric acid; and the viscosity reducer is acetone.

3. The polyurethane-based polymeric adhesive of claim 1, wherein The preparation method of the functional additive comprises the following steps: Step one, ultrasonic dispersion of vermiculite in 1,4-dioxane, then adding a surface modifier and p-toluenesulfonic acid to the formed dispersion, after adding, heating to 90-100℃, continuing to heat and stir for 6-9h, then stopping heating, cooling and discharging, collecting the solid material, washing, vacuum drying to obtain organic modified vermiculite; Step two, adding the organic modified vermiculite into N,N-dimethylformamide, ultrasonic dispersion, then adding a cycloheptane derivative and an accelerator, after adding, increasing the temperature to 60-70℃, heating for 2-3h, then adding 4,4'-diphenyl ether and further increasing the temperature to 80-90℃, continuing to heat and stir for 9-18h, then stopping heating, separating the material after cooling, washing, vacuum drying to obtain the functional additive.

4. The polyurethane-based polymeric adhesive according to claim 3, wherein In step one, the surface modifier is mercaptopropionic acid or 4-mercaptobutyric acid.

5. The polyurethane-based polymeric adhesive of claim 3, wherein the polyol is a polyether polyol. In step one, the cycloheptane derivative is prepared by the following method: adding 2-(dicycloheptane) dimethyl chlorosilane and 3-[bis(glycidyl oxymethyl) methoxy]-1,2-propanediol into tetrahydrofuran, mechanically stirring to mix uniformly, increasing the temperature to 60-65℃, adding triethylamine, stirring for 6-9h, then evaporating to remove the solvent, collecting the crude product, purifying to obtain the cycloheptane derivative.

6. The polyurethane-based polymeric adhesive according to claim 5, wherein The molar ratio of 2-(dicycloheptane) dimethyl chlorosilane and 3-[bis(glycidyl oxymethyl) methoxy]-1,2-propanediol is 1-2:

1.

7. The polyurethane-based polymeric adhesive of claim 3, wherein the polyol is a polyether polyol. In step two, the accelerator is triethylamine, tri-n-butylamine, N,N-dimethylcyclohexylamine or N,N-dimethylbenzylamine.

8. The polyurethane-based polymeric adhesive of claim 3, wherein In step two, the mass ratio of the organic modified vermiculite, the cycloheptane derivative and 4,4'-diphenyl ether is 1:0.2-0.4:0.1-0.

2.

9. A method of producing the polyurethane-based polymer adhesive according to claim 1, characterized by, comprises the following steps: The first step, under the temperature condition of 100-110℃, the polyether diol is vacuum dehydrated, then the polyether diol, diisocyanate monomer and catalyst are stirred and mixed uniformly under the temperature condition of 50-60℃, the temperature is adjusted to 70-75℃, after stirring for 2-4h, the temperature is adjusted to 40-50℃ again, the viscosity reducer is added, after stirring uniformly, the chain extender and functional additive are continuously added, and stirring is continued for 2-4h, to obtain a polymerized material; The second step, deionized water is added to the polymerized material, and stirring and emulsification are carried out for 1-2h, and the viscosity reducer is removed by evaporation, to obtain a polymerized emulsion; The third step, the defoaming agent is added to the polymerized emulsion, and stirring is carried out for 10-20min, and defoaming is carried out after standing, to obtain a high-molecular adhesive.