Carboxyl-terminated nitrile rubber modified epoxy resin and preparation method thereof, high-strength single-component adhesive for vehicles and preparation and use methods of high-strength single-component adhesive

Abstract

The invention relates to the technical field of chemistry, and mainly relates to carboxyl-terminated nitrile rubber modified epoxy resin and a preparation method thereof, and a high-strength single-component adhesive for vehicles and preparation and use methods thereof. The preparation method of the carboxyl-terminated butadiene-acrylonitrile rubber modified epoxy resin comprises the following steps: adding carboxyl-terminated butadiene-acrylonitrile rubber into epoxy resin E51, adding an initiator, heating, carrying out a first stirring reaction under vacuum, adding polyether amine T5000, and carrying out a second stirring reaction to obtain the carboxyl-terminated butadiene-acrylonitrile rubber modified epoxy resin. The carboxyl-terminated nitrile rubber modified epoxy resin prepared by the invention is good in performance, and can improve the mechanical strength and the bonding strength after being applied to an adhesive. According to the invention, the aliphatic carbon long chain is added, so that a chain segment composed of a cured product is softer and higher in degree of freedom, the toughness of colloid is better, and meanwhile, the introduced aliphatic long chain is also beneficial to improving the low-temperature resistance of the adhesive and improving the defect that epoxy resin is easy to brittle and crack at low temperature.

Description

Technical Field

[0001] The present application relates to the field of chemical technology, and mainly to a carboxyl-terminated nitrile rubber modified epoxy resin and a preparation method thereof, a high-strength single-component adhesive for vehicles and a preparation and use method thereof. Background Art

[0002] In the context of the rapid development of today's automobile industry, adhesives, as an important automotive material, are gradually showing their unique importance. With consumers' continuous pursuit of automobile performance, safety and durability, adhesives are playing an increasingly critical role in the connection and fixation of key parts such as automobile bodies, chassis, and engines. They can not only effectively improve the safety and durability of vehicles, but also significantly improve the assembly efficiency of vehicles, providing strong support for automobile manufacturers.

[0003] In the field of new energy vehicles, the demand for adhesives is showing a rapid growth trend. According to data provided by the China Adhesives and Adhesive Tapes Industry Association, the amount of adhesives used in new energy vehicles has reached 25 kilograms, which is a significant increase compared to traditional vehicles. This growth trend is also closely related to the rapid development of new energy vehicles. This trend will also greatly promote the growth of the automotive adhesive market and bring more development opportunities to the adhesive industry.

[0004] Epoxy adhesives have been widely used in automobile manufacturing and maintenance due to their excellent bonding strength to a variety of materials, chemical corrosion resistance and high temperature stability, small shrinkage, and excellent medium resistance. Single-component epoxy adhesives have outstanding advantages in bonding vehicle metal structures, fixing battery cavities, and bonding plastic frames due to their simple operation, stability at room temperature, long operating time, and fast curing speed. However, with the rapid development of the automotive industry, the performance requirements for epoxy adhesives are also increasing, especially in terms of environmental protection, high temperature resistance, and corrosion resistance. In addition, most general epoxy resin adhesives have the disadvantages of poor low temperature resistance, high brittleness after curing, and low peel strength, which limits their application in many fields. Therefore, the existing technology still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of this application is to provide a carboxyl-terminated nitrile rubber modified epoxy resin and a preparation method, a high-strength one-component adhesive for vehicles and a preparation and use method, aiming to solve the problems of existing epoxy resin adhesives such as poor low-temperature resistance, high brittleness after curing, and low peel strength.

[0006] The technical solution of this application is as follows: In a first aspect, the present application provides a method for preparing a carboxyl-terminated nitrile rubber modified epoxy resin, which comprises the following steps: The carboxyl-terminated nitrile rubber is added to the epoxy resin E51, and then an initiator is added and heated. After the first stirring reaction under vacuum, polyetheramine T5000 is added and stirred for a second time to obtain the carboxyl-terminated nitrile rubber modified epoxy resin.

[0007] The carboxyl-terminated nitrile rubber modified epoxy resin prepared in the present application has good performance and can improve mechanical strength and bonding strength after being applied to adhesives. The introduced long fatty chains also help to improve the low temperature resistance of the adhesive and improve the shortcoming of epoxy resin being prone to brittle cracking at low temperatures.

[0008] Furthermore, the added weight of the carboxyl-terminated nitrile rubber is 10%-20% of the epoxy resin E51; The added weight of the polyetheramine T5000 is 5%-10% of the epoxy resin E51; The added weight of the initiator is 0.2% of the epoxy resin E51; The initiator is triphenylphosphine.

[0009] Further, the heating temperature is 100-120°C; The stirring speed of the first stirring reaction is 100-200r / min, and the reaction time is 3-5h; The stirring speed of the second stirring reaction is 100-200 r / min, and the reaction time is 1-2 h.

[0010] In a second aspect, the present application provides a carboxyl-terminated nitrile rubber modified epoxy resin, wherein the epoxy resin is prepared by the preparation method of the carboxyl-terminated nitrile rubber modified epoxy resin as described in the first aspect.

[0011] In a third aspect, the present application provides a high-strength one-component adhesive for vehicles, which comprises the following components in parts by weight: 40-60 parts of liquid epoxy resin, 5-20 parts of solid epoxy resin ultrafine powder, 1-10 parts of epoxy reactive diluent, 7-12 parts of latent curing agent, 1-6 parts of accelerator, 0.5-5 parts of tackifier, 10-40 parts of filler, 0.5-10 parts of additive; The liquid epoxy resin is a combination of a first epoxy resin and a second epoxy resin, and the weight ratio of the first epoxy resin to the second epoxy resin is 1:1-5; The first epoxy resin is the carboxyl-terminated nitrile rubber modified epoxy resin as described in the second aspect; The second epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and polyurethane modified epoxy resin.

[0012] Furthermore, the bisphenol A type epoxy resin is one or both of epoxy resin E51 and epoxy resin E44; The polyurethane modified epoxy resin is epoxy resin DER791; The bisphenol F epoxy resin is NPEF-170; The epoxy reactive diluent is one or more of cardanol glycidyl ether, lauryl alcohol glycidyl ether, C8-10-alkyl glycidyl ether, bis((3,4-epoxycyclohexyl)methyl)adipate, resorcinol bisglycidyl ether, 1,4-butanediol glycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and propylene glycol diglycidyl ether; The solid epoxy resin ultrafine powder is one or both of solid epoxy resin E12 ultrafine powder and solid epoxy resin E20 ultrafine powder; The particle size of the solid epoxy resin ultrafine powder is less than 10 microns.

[0013] Furthermore, the latent curing agent is one or more of dicyandiamide or dicyandiamide modified homologues; The accelerator is one or more of imidazole compounds and their derivatives, salts of imidazole compounds, urea derivatives, organic guanidine derivatives, phosphorus-containing compounds, transition metal complexes and composite accelerators; The imidazole compounds and their derivatives are imidazole, 2-methylimidazole, and 2-ethyl-4-methylimidazole; The salt of the imidazole compound is an imidazole salt complex generated by the reaction of imidazole and an inorganic salt of a transition metal; The organic guanidine derivatives are substituted phenylguanidines and guanidine salts; the substituted phenylguanidines are o-tolyl biguanide and diphenylguanidine, and the guanidine salts are guanidine nitrate and guanidine phosphate; The urea derivatives are diphenylthiourea, tetramethylthiourea, diethylthiourea, N,N'-di-o-tolylthiourea, and organic urea accelerator LC-100.

[0014] Furthermore, the tackifier is liquid polysulfide rubber; The filler is one or more of nano-alumina, titanium dioxide, fumed silica, wollastonite, calcium carbonate, and quartz powder; The auxiliary agent is one or more of a defoamer, a plasticizer, a dispersant, an adhesion promoter, and a leveling agent; The plasticizer is one or more of dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, butyl benzyl phthalate, and di(2-ethyl)hexyl phthalate; The leveling agent is an acrylic leveling agent; The defoamer is one of a polysiloxane defoamer, a non-silicon defoamer, a polyether defoamer, and a mineral oil defoamer; The dispersant is one of fatty acid polyethylene glycol ester, polyether type hyperdispersant, polyester type hyperdispersant, and polyacrylate type hyperdispersant; The adhesion promoter is one of a silane coupling agent and a titanate coupling agent.

[0015] In a fourth aspect, the present application provides a method for preparing the high-strength one-component adhesive for vehicles as described in the third aspect, comprising the following steps: Mixing the liquid epoxy resin and the epoxy reactive diluent at 30-60° C.; Add the accelerator, auxiliary agent and tackifier and mix, then add the solid epoxy resin ultrafine powder and filler and disperse; Then add the latent curing agent, stir and mix, and then evacuate for 1-2 hours.

[0016] In a fifth aspect, the present application provides a method for using the high-strength one-component adhesive for vehicles as described in the third aspect, comprising the following steps: Use organic solvents to clean the surface of the substrate; Applying the high-strength one-component adhesive for vehicles on the surface of a substrate by a gluing tool; Then place the substrate in an environment of 100-180°C for 0.5-6 hours to complete curing.

[0017] Beneficial effects: The carboxyl-terminated nitrile rubber modified epoxy resin prepared in the present application has good performance, and can improve mechanical strength and bonding strength after being applied to adhesives. The present application participates in the modification of epoxy resin by adding polyetheramine, changes the bonding order of the molecular chains therein and improves the performance of the adhesive, while avoiding the adverse effects that may be caused by direct mixing of polyetheramine. By adding aliphatic carbon long chains, the chain segments composed of the cured product are made softer and have a higher degree of freedom, so the toughness of the colloid is better. At the same time, the introduced aliphatic long chains also help to improve the low temperature resistance of the adhesive and improve the disadvantage that the epoxy resin is prone to brittle cracking at low temperatures. DETAILED DESCRIPTION

[0018] The present application provides a carboxyl-terminated nitrile rubber modified epoxy resin and a preparation method, a high-strength one-component adhesive for vehicles and a preparation and use method. In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] The present application provides a method for preparing a carboxyl-terminated nitrile rubber modified epoxy resin, which comprises the following steps: The carboxyl-terminated nitrile rubber is added to the epoxy resin E51, and then the initiator is added and heated. After the first stirring reaction under vacuum, the polyetheramine T5000 is added and stirred for the second time to obtain the carboxyl-terminated nitrile rubber modified epoxy resin.

[0020] The carboxyl-terminated nitrile rubber modified epoxy resin prepared in the present application has good performance and can improve mechanical strength and bonding strength after being applied to adhesives. The present application adds aliphatic carbon long chains to make the chain segments composed of the cured product softer and more free, so that the toughness of the colloid is better. At the same time, the introduced aliphatic long chains also help to improve the low temperature resistance of the adhesive and improve the shortcoming of epoxy resin being prone to brittle cracking at low temperatures.

[0021] The reaction can be carried out in a container such as a three-necked flask.

[0022] Furthermore, the added weight of the initiator is 0.2% of the added weight of the epoxy resin E51; the initiator is triphenylphosphine.

[0023] Furthermore, the added weight of the carboxyl-terminated nitrile rubber is 10%-20% of the added weight of the epoxy resin E51.

[0024] In the present application, selected epoxy resin E51 is the epoxy resin widely used at present, and price is lower, and viscosity is moderate, and dispersion effect is good. And selected carboxyl-terminated acrylonitrile-butadiene rubber has the extremely strong-CN base of polarity, has good miscibility with epoxy resin, except can improve modification effect, also helps to guarantee the compatibility degree in adhesive. And the molecular chain two ends of carboxyl-terminated acrylonitrile-butadiene rubber are active carboxyl functional groups, can in chemical copolymerization and curing process, carboxyl at two ends and epoxy resin generation cross-linking reaction form block structure, this reaction is to react with the hydroxyl of epoxy resin, does not affect its oxirane value. After being dispersed in epoxy resin matrix, can reach toughening modification effect in prepolymerization and curing reaction process.

[0025] Specifically, the present application significantly improves the performance of epoxy resin by using a suitable proportion of terminal carboxyl nitrile rubber. If the dosage is too low, the improvement effect is not obvious. If the dosage is too high, the performance will decline. If the content of terminal carboxyl nitrile rubber is too high, the greater the proportion of flexible segments, the lower the performance of the obtained adhesive body will be.

[0026] Furthermore, the added weight of polyetheramine T5000 is 5%-10% of the added weight of epoxy resin E51.

[0027] In the adhesive system of the present application, the selected polyetheramine T5000 is a trifunctional primary amine with an average molecular weight of about 5000. As a three-branched structure, after controlling the appropriate dosage, it can improve the crosslinking density to a certain extent. If the molecular weight is too low, it will not have much effect on improving the toughness. If the molecular weight is too high or the dosage is too high, it will easily lead to a decrease in the mechanical properties of the colloid. By selecting the polyetheramine T5000, the amino group (-NH 2 ) can undergo a ring-opening addition reaction with the epoxy groups in the epoxy resin, and the long-chain polyether structure contained therein is embedded in the epoxy network during the curing process, providing the flexibility of the molecular chain, thereby improving the impact resistance and toughness of the adhesive layer. Secondly, the rich ether bonds contained in the polyetheramine have a good effect on improving the low-temperature resistance, allowing the adhesive to remain flexible at low temperatures and avoid brittle cracking.

[0028] Specifically, the substrate used for the whole automobile is more, such as metal, plastic, rubber, etc. The carboxyl-terminated nitrile rubber used in this application has a very polar -CN group, and polyetheramine T5000 also has more polar groups, which can further improve the bonding ability of epoxy resin and ensure its good adhesion to different surfaces. The adhesive with super strong bonding strength provided in this application can achieve stable bonding between different substrates, and the bonding strength is high enough, so it can meet the bonding requirements between different materials in the automobile, and realize multiple uses of one glue.

[0029] The carboxyl-terminated nitrile rubber modified epoxy resin prepared in the present application has good performance, can improve the bonding performance of the adhesive, and at the same time improve the toughness and low-temperature resistance of the colloid, which is conducive to meeting the performance requirements of the automobile.

[0030] Furthermore, the heating temperature is 100-120° C.; the stirring speed of the first stirring reaction is 100-200 r / min, and the reaction time is 3-5 h; the stirring speed of the second stirring reaction is 100-200 r / min, and the reaction time is 1-2 h.

[0031] The present application also provides a carboxyl-terminated nitrile rubber modified epoxy resin, wherein the epoxy resin is prepared by the preparation method of the carboxyl-terminated nitrile rubber modified epoxy resin as described above.

[0032] The present application also provides a high-strength one-component adhesive for vehicles, which comprises the following components in parts by weight: 40-60 parts of liquid epoxy resin, 5-20 parts of solid epoxy resin ultrafine powder, 1-10 parts of epoxy reactive diluent, 7-12 parts of latent curing agent, 1-6 parts of accelerator, 0.5-5 parts of tackifier, 10-40 parts of filler, 0.5-10 parts of additive; Wherein, the liquid epoxy resin is a combination of a first epoxy resin and a second epoxy resin, and the weight ratio of the first epoxy resin to the second epoxy resin is 1:1-5; The first epoxy resin is the carboxyl-terminated nitrile rubber modified epoxy resin as described above; The second epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and polyurethane modified epoxy resin.

[0033] In the present application, by using a carboxyl-terminated nitrile rubber modified epoxy resin in combination with other unmodified resins of lower price, the price can be relatively low while ensuring a high-strength bonding effect. Among them, if the amount of carboxyl-terminated nitrile rubber modified epoxy resin is too high, the mechanical strength of the colloid itself will be reduced, and the cost will increase. If the amount is too low, it will be difficult to achieve a performance improvement effect.

[0034] The prepared high-strength one-component automotive adhesive has excellent bonding strength, chemical corrosion resistance and high-temperature stability for a variety of materials, does not use volatile solvents, and is environmentally friendly. It has excellent low-temperature resistance, certain toughness after curing, and high peel strength. It has outstanding application prospects in vehicle metal structure bonding, battery cavity fixation, plastic frame bonding, etc., and effectively meets the performance requirements of automotive adhesives.

[0035] Furthermore, the bisphenol A type epoxy resin is one or both of epoxy resin E51 and epoxy resin E44; the polyurethane modified epoxy resin is epoxy resin DER791. Among them, the bisphenol F type epoxy resin can be NPEF-170.

[0036] Furthermore, the solid epoxy resin ultrafine powder is one or both of solid epoxy resin E12 ultrafine powder and solid epoxy resin E20 ultrafine powder; the particle size of the solid epoxy resin ultrafine powder is less than 10 microns.

[0037] In the present application, the smaller the particle size of the solid epoxy resin ultrafine powder is, the better the dispersibility is, the more uniform the obtained adhesive colloid is, and the better the curing effect is.

[0038] Furthermore, the epoxy reactive diluent is one or more of cardanol glycidyl ether, lauryl alcohol glycidyl ether, C8~10-alkyl glycidyl ether, bis((3,4-epoxycyclohexyl)methyl)adipate, resorcinol bisglycidyl ether, 1,4-butanediol glycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and propylene glycol diglycidyl ether.

[0039] Furthermore, the latent curing agent is one or more of dicyandiamide or dicyandiamide modified homologues, wherein the dicyandiamide modified homologues may specifically be one of diaminodiphenylmethane modified dicyandiamide and 4,4'-diaminodiphenyl sulfone (DDS) modified dicyandiamide.

[0040] Furthermore, the accelerator is one or more of imidazole compounds and their derivatives, salts of imidazole compounds, urea derivatives, organic guanidine derivatives, phosphorus-containing compounds, transition metal complexes and composite accelerators. Among them, imidazole compounds and their derivatives are imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole; the salt of imidazole compounds is an imidazole salt complex generated by the reaction of imidazole with an inorganic salt of a transition metal, and the transition metal is specifically Cu, Ni, Co, Zn, etc.; the organic guanidine derivatives are substituted phenylguanidines and guanidine salts; the substituted phenylguanidines are o-tolylbiguanide (OTBG) and diphenylguanidine (DCP), and the guanidine salts are guanidine nitrate and guanidine phosphate; the urea derivatives are diphenylthiourea (DPTU), tetramethylthiourea (TMTU), diethylthiourea (DETU), N,N'-di-o-tolylthiourea (DOTU), and the organic urea accelerator LC-100.

[0041] In the present application, the selected accelerator can be used alone or in combination. For example, imidazole can be used as a ligand to coordinate with a phosphorus-containing metal complex (such as an organic phosphine metal complex) to form a stable complex; imidazole and organic urea can be used in combination to significantly reduce the curing temperature. The addition of an accelerator can reduce the curing temperature, which is conducive to achieving medium-temperature curing and fast curing speed.

[0042] Furthermore, the tackifier is liquid polysulfide rubber.

[0043] Furthermore, the filler is one or more of nano-alumina, titanium dioxide, fumed silica, wollastonite, calcium carbonate, and quartz powder. There is no special requirement for the particle size of the filler, which can generally meet the requirements of commercial products.

[0044] The calcium carbonate is heavy calcium carbonate (heavy calcium carbonate). In the present application, heavy calcium carbonate is cheaper as a filler, which can reduce the cost of the adhesive, and compared with light calcium carbonate, heavy calcium carbonate is not easy to absorb moisture in the air, which can reduce the influence of moisture on the colloid properties of the adhesive.

[0045] Furthermore, the auxiliary agent is one or more of a defoamer, a plasticizer, a dispersant, an adhesion promoter, and a leveling agent.

[0046] Furthermore, the plasticizer is one or more of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), dioctyl phthalate (DOP), butyl benzyl phthalate (BBP), and di(2-ethyl)hexyl phthalate (DEHP).

[0047] Furthermore, the leveling agent is an acrylic leveling agent, and existing products available on the market can also be selected.

[0048] Furthermore, the defoamer is one of polysiloxane defoamer, non-silicon defoamer, polyether defoamer, mineral oil defoamer, and existing commercial products can also be selected.

[0049] Furthermore, the dispersant is one of fatty acid polyethylene glycol ester, polyether type hyperdispersant, polyester type hyperdispersant, polyacrylate type hyperdispersant, and commercially available products can also be selected.

[0050] Furthermore, the adhesion promoter is one of a silane coupling agent and a titanate coupling agent, preferably a silane coupling agent.

[0051] The present application also provides a method for preparing the high-strength one-component adhesive for vehicles as described above, which comprises the following steps: Mix the liquid epoxy resin and epoxy reactive diluent at 30-60°C; Add accelerator, auxiliary agent and tackifier to mix, then add solid epoxy resin ultrafine powder and filler to disperse; Then add the latent curing agent, stir and mix, and then evacuate for 1-2 hours to obtain a high-strength single-component adhesive for automobiles.

[0052] The present application also provides a method for using the above-mentioned high-strength one-component adhesive for vehicles, which comprises the following steps: Use organic solvents to clean the surface of the substrate; Applying a high-strength one-component adhesive for automobiles on the surface of the substrate by a glue application tool; Then place the substrate in an environment of 100-180°C for 0.5-6 hours to complete curing.

[0053] The organic solvent may be ethanol; the gluing tool may be a glue gun, a coating rod, a glue brush, or other extrusion devices, etc., as long as the adhesive can be evenly applied.

[0054] The high-strength one-component adhesive for vehicles provided in the present application is simple to construct, stable at room temperature and has a long operability time.

[0055] The invention is further described below by means of specific examples.

[0056] The preparation method of the carboxyl-terminated nitrile rubber modified epoxy resin used in the embodiment of the present application comprises the following steps: Weigh epoxy resin E51 and add it into a three-necked flask, add 20% of the weight of the epoxy resin E51 added carboxyl-terminated nitrile rubber, then add 0.2% of the weight of the epoxy resin E51 added triphenylphosphine, heat to 120°C, stir and react for the first time under vacuum, the stirring speed is 200 r / min, the reaction time is 5 hours, and a mixed solution is obtained; Add 5% of the weight of the epoxy resin E51 to the mixed solution of polyetheramine T5000, continue to maintain the temperature at 120°C and vacuum conditions for a second stirring reaction, the stirring speed is 200 r / min, the reaction time is 2 h, and the carboxyl-terminated nitrile rubber modified epoxy resin is obtained.

[0057] Example 1 The high-strength one-component adhesive for vehicles of Example 1 comprises the following components in parts by weight: 60 parts of liquid epoxy resin, 10 parts of solid epoxy resin ultrafine powder, 5 parts of epoxy reactive diluent, 12 parts of latent curing agent, 4 parts of accelerator, 0.5 parts of tackifier, 40 parts of filler, 3 parts of additive; Among them, the liquid epoxy resin is a combination of epoxy resin E51 and terminal carboxyl nitrile rubber modified epoxy resin, and the corresponding weight ratio is 2:1; the solid epoxy resin ultrafine powder is solid epoxy resin E12 ultrafine powder; the epoxy reactive diluent is cardanol glycidyl ether; the latent curing agent is dicyandiamide; the accelerator is organic urea accelerator LC-100; the tackifier is liquid polysulfide rubber; the filler is a combination of nano alumina and heavy calcium, and the corresponding weight ratio is 1:10; the auxiliary agent is a combination of non-silicon defoamer and dioctyl phthalate plasticizer, and the corresponding weight ratio is 0.5:2.

[0058] The method for preparing the high-strength one-component adhesive for vehicles of Example 1 comprises the following steps: Mix the liquid epoxy resin and the epoxy reactive diluent at 45°C; Add accelerator, auxiliary agent and tackifier to mix, then add solid epoxy resin ultrafine powder and filler to disperse; Then, a latent curing agent is added, stirred and mixed, and then vacuumed for 2 hours to obtain the high-strength one-component adhesive for vehicles of Example 1.

[0059] The method for using the high-strength one-component adhesive for vehicles of Example 1 comprises the following steps: Use ethanol to clean the surface of the substrate to be bonded; Applying a high-strength one-component adhesive for automobiles to the surface of the substrate by means of a glue gun; The substrate was then placed in an environment of 150°C for 4 hours to complete curing.

[0060] Example 2 The high-strength one-component adhesive for vehicles of Example 2 comprises the following components in parts by weight: 40 parts of liquid epoxy resin, 20 parts of solid epoxy resin ultrafine powder, 8 parts of epoxy reactive diluent, 10 parts of latent curing agent, 2 parts of accelerator, 1 part of tackifier, 40 parts of filler, 2 parts of additive; Among them, the liquid epoxy resin is a combination of epoxy resin E44 and terminal carboxyl nitrile rubber modified epoxy resin, and the corresponding weight ratio is 1:1; the solid epoxy resin ultrafine powder is solid epoxy resin E20 ultrafine powder; the epoxy reactive diluent is C8~10-alkyl glycidyl ether; the latent curing agent is dicyandiamide; the accelerator is 2-methylimidazole; the tackifier is liquid polysulfide rubber; the filler is heavy calcium; the auxiliary agent is a combination of acrylic defoamer and dibutyl phthalate plasticizer, and the corresponding weight ratio is 0.5:1.

[0061] The high-strength one-component adhesive for vehicles of Example 2 was prepared by the same preparation method as that of Example 1. The use method of the high-strength one-component adhesive for vehicles of Example 2 was the same as that of Example 1.

[0062] Example 3 The high-strength one-component adhesive for vehicles of Example 3 comprises the following components in parts by weight: 50 parts of liquid epoxy resin, 5 parts of solid epoxy resin ultrafine powder, 10 parts of epoxy reactive diluent, 12 parts of latent curing agent, 1 part of accelerator, 0.5 parts of tackifier, 30 parts of filler, 0.6 parts of auxiliary agent; Among them, the liquid epoxy resin is a combination of epoxy resin E44 and terminal carboxyl nitrile rubber modified epoxy resin, and the corresponding weight ratio is 1:1; the solid epoxy resin ultrafine powder is solid epoxy resin E20 ultrafine powder; the epoxy reactive diluent is resorcinol diglycidyl ether; the latent curing agent is diaminodiphenylmethane modified dicyandiamide; the accelerator is diphenylguanidine; the tackifier is liquid polysulfide rubber; the filler is heavy calcium; the auxiliary agent is a combination of polyether defoamer, dibutyl phthalate plasticizer and titanate coupling agent, and the corresponding weight ratio is 0.5: 0.5:1.

[0063] The high-strength one-component adhesive for vehicles of Example 3 was prepared by the same preparation method as that of Example 1. The use method of the high-strength one-component adhesive for vehicles of Example 3 was the same as that of Example 1.

[0064] Example 4 The high-strength one-component adhesive for vehicles of Example 4 comprises the following components in parts by weight: 45 parts of liquid epoxy resin, 8 parts of solid epoxy resin ultrafine powder, 6 parts of epoxy reactive diluent, 8 parts of latent curing agent, 5 parts of accelerator, 4 parts of tackifier, 35 parts of filler, 6 parts of auxiliary agent; Among them, the liquid epoxy resin is a combination of polyurethane modified epoxy resin (epoxy resin DER791) and terminal carboxyl nitrile rubber modified epoxy resin, and the corresponding weight ratio is 2:1; the solid epoxy resin ultrafine powder is solid epoxy resin E20 ultrafine powder; the epoxy reactive diluent is bis((3,4-epoxycyclohexyl)methyl)adipate; the latent curing agent is 4,4'-diaminodiphenyl sulfone modified dicyandiamide; the accelerator is dicyandiamide accelerator UR500; the tackifier is liquid polysulfide rubber; the filler is a combination of fumed silica, titanium dioxide, and heavy calcium, and the corresponding weight ratio is 0.5:20:20; the auxiliary agent is a combination of mineral oil defoamer, di(2-ethyl)hexyl phthalate plasticizer, and silane coupling agent, and the corresponding weight ratio is 0.1:1:1.

[0065] The high-strength one-component adhesive for vehicles of Example 4 was prepared by the same preparation method as that of Example 1. The use method of the high-strength one-component adhesive for vehicles of Example 4 was the same as that of Example 1.

[0066] Example 5 The high-strength one-component adhesive for vehicles of Example 5 comprises the following components in parts by weight: 50 parts of liquid epoxy resin, 20 parts of solid epoxy resin ultrafine powder, 1 part of epoxy reactive diluent, 12 parts of latent curing agent, 6 parts of accelerator, 5 parts of tackifier, 40 parts of filler, 8 parts of auxiliary agent; Among them, the liquid epoxy resin is a combination of epoxy resin E51, bisphenol F type epoxy resin NPEF-170 and terminal carboxyl nitrile rubber modified epoxy resin, and the corresponding weight ratio is 2:1; the solid epoxy resin ultrafine powder is solid epoxy resin E12 ultrafine powder; the epoxy active diluent is 1,6-hexanediol diglycidyl ether; the latent curing agent is dicyandiamide; the accelerator is dicyandiamide accelerator UR300; the tackifier is liquid polysulfide rubber; the filler is a combination of wollastonite, calcium carbonate and nano alumina, and the corresponding weight ratio is 10:10:0.5; the auxiliary agent is a combination of polysiloxane defoamer, butyl benzyl phthalate plasticizer, polyester type hyperdispersant and silane coupling agent, and the corresponding weight ratio is 0.1:4:0.2:1.

[0067] The high-strength one-component adhesive for vehicles of Example 5 was prepared by the same preparation method as that of Example 1. The use method of the high-strength one-component adhesive for vehicles of Example 5 was the same as that of Example 1.

[0068] Comparative Example 1 The one-component adhesive for automobiles of Comparative Example 1 comprises the following components in parts by weight: 60 parts of liquid epoxy resin, 10 parts of solid epoxy resin ultrafine powder, 5 parts of epoxy reactive diluent, 12 parts of latent curing agent, 4 parts of accelerator, 0.5 parts of tackifier, 40 parts of filler, 3 parts of additive; Among them, the liquid epoxy resin is a combination of epoxy resin E51 and commercially available carboxyl-terminated nitrile rubber modified epoxy resin EPR-1630, and the corresponding weight ratio is 2:1; the solid epoxy resin ultrafine powder is solid epoxy resin E12 ultrafine powder; the epoxy reactive diluent is cardanol glycidyl ether; the latent curing agent is dicyandiamide; the accelerator is an organic urea accelerator; the viscosity enhancer is liquid polysulfide rubber; the filler is a combination of nano-alumina and heavy calcium, and the corresponding weight ratio is 1:10; the auxiliary agent is a combination of a non-silicon defoamer and a dioctyl phthalate plasticizer, and the corresponding weight ratio is 0.5:2.

[0069] The automotive one-component adhesive of Comparative Example 1 was prepared by the same preparation method as Example 1.

[0070] Comparative Example 2 The one-component adhesive for automobiles of Comparative Example 2 comprises the following components in parts by weight: 60 parts of liquid epoxy resin, 5 parts of epoxy reactive diluent, 10 parts of latent curing agent, 4 parts of accelerator, 0.5 parts of tackifier, 40 parts of filler, 3 parts of additive; Among them, the liquid epoxy resin is a combination of epoxy resin E51 and commercially available carboxyl-terminated nitrile rubber modified epoxy resin EPR-1630, and the corresponding weight ratio is 2:1; the epoxy reactive diluent is cardanol glycidyl ether; the latent curing agent is dicyandiamide; the accelerator is an organic urea accelerator; the tackifier is liquid polysulfide rubber; the filler is a combination of nano-alumina and heavy calcium, and the corresponding weight ratio is 1:10; the auxiliary agent is a combination of a non-silicon defoamer and a dioctyl phthalate plasticizer, and the corresponding weight ratio is 0.5:2.

[0071] The automotive one-component adhesive of Comparative Example 2 was prepared by the same preparation method as Example 1.

[0072] Comparative Example 3 The one-component adhesive for automobiles of Comparative Example 3 comprises the following components in parts by weight: 60 parts of liquid epoxy resin, 10 parts of solid epoxy resin ultrafine powder, 5 parts of epoxy reactive diluent, 12 parts of latent curing agent, 1.5 parts of polyether amine curing agent, 4 parts of accelerator, 0.5 parts of tackifier, 40 parts of filler, 3 parts of auxiliary agent Among them, the liquid epoxy resin is a combination of epoxy resin E51 and modified epoxy resin (prepared under the same reaction conditions as the carboxyl-terminated nitrile rubber modified epoxy resin in the embodiment of the present application, the only difference being that polyetheramine T5000 is not added), and the corresponding weight ratio is 2:1; the solid epoxy resin ultrafine powder is solid epoxy resin E12 ultrafine powder; the epoxy reactive diluent is cardanol glycidyl ether; the latent curing agent is dicyandiamide; the polyetheramine curing agent is polyetheramine T5000; the accelerator is organic urea accelerator LC-100; the tackifier is liquid polysulfide rubber; the filler is a combination of nano-alumina and heavy calcium, and the corresponding weight ratio is 1:10; the auxiliary agent is a combination of a non-silicon defoamer and a dioctyl phthalate plasticizer, and the corresponding weight ratio is 0.5:2.

[0073] The automotive one-component adhesive of Comparative Example 3 was prepared by the same preparation method as Example 1. The preparation method of the modified epoxy resin used in Comparative Example 3 comprises the following steps: Weigh epoxy resin E51 and add it into a three-necked flask, add terminal carboxyl nitrile rubber which is 20% by weight of epoxy resin E51, then add triphenylphosphine which is 0.2% by weight of epoxy resin E51, heat to 120°C, stir and react for the first time under vacuum at a stirring speed of 200 r / min and a reaction time of 5 h to obtain a modified epoxy resin.

[0074] The adhesives prepared in the embodiments and comparative examples were subjected to performance tests, and the test methods were as follows: (1) Tensile strength: The test was conducted in accordance with the method of GB / T528-2009. The body specimens were prepared in accordance with the method of GB / T 22376.2-2008. The test was conducted using a 50 KN universal material testing machine at room temperature and -20°C.

[0075] (2) Elongation at break: The test was conducted in accordance with the method of GB / T528-2009. The body specimens were prepared in accordance with the method of GB / T 22376.2-2008. The tests were conducted using a 50 KN universal materials testing machine at room temperature and -20°C.

[0076] (3) Shear strength: The test was conducted in accordance with the method of GB / T 7124-2008. The bonding parts were made of tinplate sheets and were degreased and cleaned. The test was conducted using a 50 KN universal material testing machine at room temperature and -20°C.

[0077] (4) T-peel strength: tested in accordance with the method of GB / T 2791-1995 using a 1 KN universal material testing machine.

[0078] The test results are shown in Table 1: Table 1

[0079] By comparing the test results, it can be found that although Comparative Example 1 still maintains a certain tensile strength, elongation at break, shear strength and peel strength are not as good as the present application embodiment, and the overall bonding effect is worse. The one-component adhesive of the present application embodiment has higher tensile strength, elongation at break, shear strength and peel strength, and excellent low temperature resistance. As can be seen from Examples 1-5, the use of the application's homemade carboxyl-terminated nitrile rubber modified epoxy resin and the use of liquid polysulfide rubber as a tackifier have excellent toughness and tensile strength.

[0080] It can be seen from the results of Example 1 and Comparative Example 1 that, when other components are the same, the one-component adhesive prepared using the carboxyl-terminated nitrile rubber modified epoxy resin prepared by the present invention has better mechanical strength and bonding strength than the commercially available nitrile rubber modified epoxy resin. This is because after the addition of aliphatic carbon long chains, the chain segments constituting the cured product are softer and have a higher degree of freedom, so the toughness of the colloid is better. At the same time, the introduction of aliphatic long chains also helps to improve the low-temperature resistance of the adhesive and improve the disadvantage that the epoxy resin is prone to brittle cracking at low temperatures.

[0081] It can be seen from the results of Example 1 and Comparative Examples 1 and 2 that, when other components are the same, the epoxy adhesive to which the ultrafine epoxy resin powder component is added has better mechanical strength and bonding strength. This is because the ultrafine epoxy resin powder can be used as a solid raw material to increase the viscosity of the adhesive. On the other hand, since the ultrafine epoxy resin powder itself has a long molecular chain segment, it also helps to improve the toughness of the adhesive itself.

[0082] The amount of polyetheramine T5000 used in Comparative Example 3 is equivalent to that in Example 1, but the order of addition is different, and polyetheramine T5000 does not participate in the modification process of the modified epoxy resin. Polyetheramine T5000 has good activity, and the prepared adhesive is easy to cure prematurely when placed at room temperature, affecting the viscosity and stability of the adhesive. It can also be seen from the results of Example 1 and Comparative Example 3 that if the adhesive system of the present application is directly mixed with polyetheramine T5000, the molecular chain bonding order will be changed and the performance will be reduced, affecting the use.

[0083] The high-strength single-component adhesive for vehicles prepared in the present application has good mechanical properties and bonding strength at room temperature and low temperature, and has outstanding application prospects in vehicle metal structure bonding, battery cavity fixation, plastic frame bonding, etc.

[0084] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the scope of protection of the present application.

Claims

1. A method for preparing a carboxyl-terminated nitrile rubber modified epoxy resin, characterized in that: The following steps are involved: The carboxyl-terminated nitrile rubber is added to the epoxy resin E51, and then an initiator is added and heated. After the first stirring reaction under vacuum, polyetheramine T5000 is added and stirred for a second time to obtain the carboxyl-terminated nitrile rubber modified epoxy resin.

2. The method for preparing a carboxyl-terminated nitrile rubber modified epoxy resin according to claim 1, wherein The added weight of the carboxyl-terminated nitrile rubber is 10%-20% of the epoxy resin E51; The added weight of the polyetheramine T5000 is 5%-10% of the epoxy resin E51; The added weight of the initiator is 0.2% of the epoxy resin E51; The initiator is triphenylphosphine.

3. The method for preparing a carboxyl-terminated nitrile rubber modified epoxy resin according to claim 1, wherein The heating temperature is 100-120°C; The stirring speed of the first stirring reaction is 100-200r / min, and the reaction time is 3-5h; The stirring speed of the second stirring reaction is 100-200 r / min, and the reaction time is 1-2 h.

4. A carboxyl-terminated nitrile rubber modified epoxy resin, characterized in that: The epoxy resin is prepared by the method for preparing the carboxyl-terminated nitrile rubber modified epoxy resin as described in any one of claims 1 to 3.

5. A high-strength one-component adhesive for vehicles, characterized in that: By weight, it includes the following components: 40-60 parts of liquid epoxy resin, 5-20 parts of solid epoxy resin ultrafine powder, 1-10 parts of epoxy reactive diluent, 7-12 parts of latent curing agent, 1-6 parts of accelerator, 0.5-5 parts of tackifier, 10-40 parts of filler, 0.5-10 parts of additive; The liquid epoxy resin is a combination of a first epoxy resin and a second epoxy resin, and the weight ratio of the first epoxy resin to the second epoxy resin is 1:1-5; The first epoxy resin is the carboxyl-terminated nitrile rubber modified epoxy resin as claimed in claim 4; The second epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and polyurethane modified epoxy resin.

6. The high-strength one-component adhesive for vehicles according to claim 5, characterized in that: The bisphenol A type epoxy resin is one or both of epoxy resin E51 and epoxy resin E44; The polyurethane modified epoxy resin is epoxy resin DER791; The bisphenol F epoxy resin is NPEF-170; The epoxy reactive diluent is one or more of cardanol glycidyl ether, lauryl alcohol glycidyl ether, C8-10-alkyl glycidyl ether, bis((3,4-epoxycyclohexyl)methyl)adipate, resorcinol bisglycidyl ether, 1,4-butanediol glycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and propylene glycol diglycidyl ether; The solid epoxy resin ultrafine powder is one or both of solid epoxy resin E12 ultrafine powder and solid epoxy resin E20 ultrafine powder; The particle size of the solid epoxy resin ultrafine powder is less than 10 microns.

7. The high-strength one-component adhesive for vehicles according to claim 5, characterized in that: The latent curing agent is one or more of dicyandiamide or dicyandiamide modified homologues; The accelerator is one or more of imidazole compounds and their derivatives, salts of imidazole compounds, urea derivatives, organic guanidine derivatives, phosphorus-containing compounds, transition metal complexes and composite accelerators; The imidazole compounds and their derivatives are imidazole, 2-methylimidazole, and 2-ethyl-4-methylimidazole; The salt of the imidazole compound is an imidazole salt complex generated by the reaction of imidazole and an inorganic salt of a transition metal; The organic guanidine derivatives are substituted phenylguanidines and guanidine salts; the substituted phenylguanidines are o-tolyl biguanide and diphenylguanidine, and the guanidine salts are guanidine nitrate and guanidine phosphate; The urea derivatives are diphenylthiourea, tetramethylthiourea, diethylthiourea, N,N'-di-o-tolylthiourea, and organic urea accelerator LC-100.

8. The high-strength one-component adhesive for vehicles according to claim 5, characterized in that: The tackifier is liquid polysulfide rubber; The filler is one or more of nano-alumina, titanium dioxide, fumed silica, wollastonite, calcium carbonate, and quartz powder; The auxiliary agent is one or more of a defoamer, a plasticizer, a dispersant, an adhesion promoter, and a leveling agent; The plasticizer is one or more of dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, butyl benzyl phthalate, and di(2-ethyl)hexyl phthalate; The leveling agent is an acrylic leveling agent; The defoamer is one of a polysiloxane defoamer, a non-silicon defoamer, a polyether defoamer, and a mineral oil defoamer; The dispersant is one of fatty acid polyethylene glycol ester, polyether type hyperdispersant, polyester type hyperdispersant, and polyacrylate type hyperdispersant; The adhesion promoter is one of a silane coupling agent and a titanate coupling agent.

9. A method for preparing the high-strength one-component adhesive for vehicles according to any one of claims 5 to 8, characterized in that: The following steps are involved: Mixing the liquid epoxy resin and the epoxy reactive diluent at 30-60° C.; Add the accelerator, auxiliary agent and tackifier and mix, then add the solid epoxy resin ultrafine powder and filler and disperse; Then add the latent curing agent, stir and mix, and then evacuate for 1-2 hours.

10. A method for using the high-strength one-component adhesive for vehicles as claimed in any one of claims 5 to 8, characterized in that: The following steps are involved: Use organic solvents to clean the surface of the substrate; Applying the high-strength one-component adhesive for vehicles on the surface of a substrate by a gluing tool; Then place the substrate in an environment of 100-180°C for 0.5-6 hours to complete curing.

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