Modified polyurethane primer and method for preparing the same

Abstract

The application provides a modified polyurethane primer and a preparation method thereof. The preparation raw material of the modified polyurethane primer comprises 15-25 parts of tackifying resin, 15-25 parts of crosslinking resin, 5-9 parts of pigment carbon black, 0.5-1.0 part of catalyst and 50-60 parts of solvent, the tackifying resin is obtained by the reaction of first polyester diol, diisocyanate and hydroxyl-terminated organic silicon modified rosin-based end-capping agent, the hydroxyl-terminated organic silicon modified rosin-based end-capping agent is obtained by the reaction of epoxy silane and rosin, and the crosslinking resin is obtained by the reaction of triisocyanate, second polyester diol and polyamino silane. The modified polyurethane primer provided by the application has excellent initial adhesion performance under low temperature (about 0 DEG C) conditions, meanwhile, the primer has the characteristics of strong adhesion, excellent storage stability, good durability, wide substrate adaptability and the like, is very suitable for use in cold winter environment, and can obviously shorten the fixture removal time of a main engine factory and the fast driving-off time in the after-sales market.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of primer, in particular to a modified polyurethane primer and a preparation method thereof. BACKGROUND

[0002] Polyurethane adhesive has excellent mechanical properties and low temperature flexibility, and is widely used in the bonding and sealing of automobile, rail transit windshield glass, side window glass and sheet metal. At present, the scheme of high-strength single-component moisture-curing polyurethane adhesive combined with primer is mainly used. However, the single-component polyurethane adhesive has a slow curing speed at low temperature, and the conventional primer cannot form effective bonding at low temperature. In cold winter, it cannot meet the requirements of rapid assembly line operation of the main plant and rapid departure of the after-sales market. With the rapid development of the automobile industry, many enterprises use two-component polyurethane adhesive to solve the problem of slow curing at low temperature. However, the two-component polyurethane adhesive is cured as a whole, and cannot form chemical bonding with the primer in a short time. The conventional primer cannot form effective bonding and adsorption with the sheet metal in a short time, which may cause the primer to fall off from the sheet metal.

[0003] Therefore, there is an urgent need for a modified polyurethane primer and a preparation method thereof to solve the above problems. SUMMARY

[0004] The present application relates to the technical field of primer, in particular to a modified polyurethane primer and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the present application provides a modified polyurethane primer, and the preparation raw materials include 15-25 parts by weight of tackifying resin, 15-25 parts by weight of crosslinking resin, 5-9 parts by weight of pigment carbon black, 0.5-1.0 parts by weight of catalyst and 50-60 parts by weight of solvent. The tackifying resin is obtained by reaction of first polyester diol, diisocyanate and hydroxyl-terminated organic silicon modified rosin-based end-capping agent. The hydroxyl-terminated organic silicon modified rosin-based end-capping agent is obtained by reaction of epoxy silane and rosin. The crosslinking resin is obtained by reaction of triisocyanate, second polyester diol and polyamino silane.

[0006] Compared with the prior art, the modified polyurethane primer of the present application has excellent initial adhesion at low temperature (0℃), and has the characteristics of strong adhesion, excellent storage stability, good durability and wide substrate adaptability. The specific embodiments are as follows:

[0007] (1) The present application introduces a hydroxyl-terminated silicone-modified rosin-based end-capping agent prepared by ring-opening reaction of rosin and epoxy silane into the tackifying resin of the primer of the present application, wherein the tricyclic skeleton structure of rosin molecule has excellent low-temperature initial tack and bonding properties, after solvent volatilization under low-temperature conditions, it rapidly wets and adsorbs the surface of the adherend to form initial bonding effect, and the bonding strength gradually increases with time, which can effectively improve the bonding effect of the primer on difficult-to-bond substrates, and the silane structure (-SiOCH3) of the end group dehydrates and condenses with the -OH on the surface of the substrate to form effective chemical bonding after hydrolysis.

[0008] (2) The present application introduces amine groups and silicones into the polyurethane molecule by using polyester diols and triisocyanates and polyamino silanes to obtain the crosslinking resin of the present application, wherein the triisocyanate, as a crosslinking agent, reacts with the polyester diol to increase the crosslinking degree of the film after forming, thereby improving the strength of the primer, the amine groups introduced by the side groups have high reactivity and can rapidly form chemical bonding with the polyurethane adhesive under low-temperature conditions to prevent the adhesive from debonding from the primer, and on the other hand, the synergistic reaction of the silane end group with the tackifying resin further strengthens the strength of the primer.

[0009] (3) The modified polyurethane primer of the present application is capped with silicone, and there is no free isocyanate group in the system, which has less impact on the health of the workers, and the surface tension of silicone is low, the hydrophobic ability is strong, and it has good water resistance, excellent mechanical and chemical stability from low temperature to high temperature, which can effectively improve the water resistance, high-temperature resistance, high-humidity resistance and aging resistance of the primer, and prevent debonding in harsh environments.

[0010] Preferably, the epoxy silane is selected from at least one of 3-(2,3-epoxypropoxy)propyl trimethoxysilane, 3-(2,3-epoxypropoxy)propyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane.

[0011] Preferably, the rosin is selected from at least one of hydrogenated rosin, dehydroabietic acid and refined rosin.

[0012] Preferably, the diisocyanate is selected from at least one of MDI, HDI, TDI and IPDI.

[0013] Preferably, the triisocyanate is selected from at least one of HDI trimer, IPDI trimer, TDI trimer, thiophosphoric acid triphenyl triisocyanate and triphenylmethane triisocyanate.

[0014] Preferably, the polyamino silane is selected from at least one of N-2-aminoethyl-3-aminopropyl triethoxysilane, N-2-aminoethyl-3-aminopropyl trimethoxysilane, 3-diethylenetriaminyl propyl trimethoxysilane, N-benzyl-N'-[3-(trimethoxysilyl)propyl]ethylenediamine hydrochloride and vinylbenzylaminoethylaminopropyl trimethoxysilane hydrochloride.

[0015] Preferably, the first polyester diol and the second polyester diol are each independently selected from at least one of polycarbonate diol, polycaprolactone diol and alkyd polyester diol, and the molecular weight of the first polyester diol and the second polyester diol is 1000-2000.

[0016] Preferably, the catalyst is selected from at least one of organic tin catalyst and titanate catalyst.

[0017] Preferably, the solvent is selected from at least one of ethyl acetate, butyl acetate, acetone, butanone and dimethylbenzene.

[0018] Another aspect of the present application provides a preparation method of the modified polyurethane primer described above, comprising:

[0019] (1) preparing a hydroxyl-terminated silicone-modified rosin-based end-capping agent

[0020] The rosin, the epoxy silane, triethylamine and the solvent are placed in a reactor under a protective atmosphere, and reacted at 100-105°C until the acid value of the reaction solution is less than 5 mg KOH / g, and the hydroxyl-terminated silicone-modified rosin-based end-capping agent is obtained after post-treatment, wherein the molar ratio of the epoxy group in the epoxy silane to the carboxyl group in the rosin is 1:1.

[0021] (2) preparing an adhesion-promoting resin

[0022] The diisocyanate, the solvent, the organic tin catalyst and the dehydrated first polyester diol are placed in a reactor, and reacted until the NCO reaches the theoretical value, then the hydroxyl-terminated silicone-modified rosin-based end-capping agent is added, and the NCO reaction is completed, and the adhesion-promoting resin is obtained after post-treatment.

[0023] (3) preparing a crosslinking resin

[0024] The triisocyanate, the solvent, the organic tin catalyst and the dehydrated second polyester diol are placed in a reactor, and reacted until the NCO reaches the theoretical value, then the polyamino silane is added dropwise into the reactor at 0-5°C under a protective atmosphere, and the temperature is raised to 25-30°C after the dropwise addition is completed, and the NCO reaction is completed, and the crosslinking resin is obtained after post-treatment.

[0025] (4) preparing a modified polyurethane primer

[0026] mixing the tackifying resin, the crosslinking resin, the pigment carbon black, the catalyst and the solvent uniformly.

[0027] Preferably, in step (1), the amount of triethylamine added is 0.5% of the mass of the rosin; and the post-treatment specifically comprises distilling the reaction liquid under reduced pressure to remove the first solvent.

[0028] Preferably, in step (2), the molar ratio of the first polyester diol, diisocyanate and the hydroxyl-terminated organosilicon-modified rosin-based end-capping agent is 1: (1.4-1.8): (0.8-1.6), and the amount of organotin catalyst added is 0.2% of the mass of the first polyester diol; the post-treatment specifically comprises distilling the reaction liquid under reduced pressure to remove the second solvent; and the reaction temperature is 60-70°C, and as examples, the reaction temperature specifically but not limitedly is 60°C, 62°C, 64°C, 65°C, 66°C, 68°C, 70°C, and preferably 65°C.

[0029] Preferably, in step (3), the molar ratio of the second polyester polyol, triisocyanate and the polyamino silane is 1: (2.2-2.6): (4.6-5.8), and the amount of organotin catalyst added is 0.2% of the mass of the second polyester polyol; and the post-treatment specifically comprises distilling the reaction liquid under reduced pressure to remove the third solvent.

[0030] Preferably, in step (4), the mixing uniformly specifically comprises grinding the tackifying resin, the crosslinking resin, the pigment carbon black, the catalyst and the solvent in a ball mill for 5-10h, and as examples, the grinding time specifically but not limitedly is 5h, 6h, 7h, 8h, 9h, 10h, and preferably 8h.

[0031] Preferably, the dehydration of the first polyester diol and the second polyester diol specifically comprises distilling under reduced pressure at 100-110°C until the moisture content is less than 0.03%, and the vacuum degree during the distillation under reduced pressure is ≤-0.098MPa. DETAILED DESCRIPTION

[0032] To better illustrate the purpose, technical solution and beneficial effects of the present application, the present application will be further described below in conjunction with specific examples. It should be noted that the following description of the method is a further explanation and description of the present application, and should not be regarded as a limitation of the present application.

[0033] The raw materials used in the following examples and comparative examples are all industrial grade, wherein the polycaprolactone diol is purchased from Daicel PCL 210N; the polycarbonate diol is purchased from Asahi Kasei PCDL T6001; the alkyd polyester diol is purchased from DICOD-X-355; the rosin is purchased from Songbao Chemical Refining Rosin; and the pigment carbon black is purchased from Oronite Carbon Black SB 250.

[0034] Example 1

[0035] A modified polyurethane primer is prepared from 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of Oronite Carbon Black SB 250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate, wherein the tackifying resin is obtained by reaction of polycaprolactone diol (PCL 210N), MDI and hydroxyl-terminated organosilicon modified rosin end-capping agent, the hydroxyl-terminated organosilicon modified rosin end-capping agent is obtained by reaction of 3-(2,3-epoxypropoxy)propyl trimethoxysilane and refined rosin, and the crosslinking resin is obtained by reaction of HDI trimer, polycaprolactone diol (PCL 210N) and N-2-aminoethyl-3-aminopropyl trimethoxysilane.

[0036] The preparation of the modified polyurethane primer of the present example comprises:

[0037] (1) Preparation of hydroxyl-terminated organosilicon modified rosin end-capping agent

[0038] 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.14 parts of 3-(2,3-epoxypropoxy)propyl trimethoxysilane and 0.5 parts of catalyst triethylamine are placed in a reactor under nitrogen protection, heated to 100°C, and kept at this temperature until the acid value of the product is less than 5 mg KOH / g, and then the solvent is removed by reduced pressure distillation to obtain the hydroxyl-terminated organosilicon modified rosin end-capping agent, which is sealed and stored for later use;

[0039] (2) Preparation of tackifying resin

[0040] 100 parts of polycaprolactone diol are placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0041] ≤-0.098 MPa) until the moisture content is less than 0.03%, then cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate are added, and the reaction is continued until the NCO content is 1.74%, then 64.66 parts of the hydroxyl-terminated organosilicon modified rosin end-capping agent is added until the NCO reaction is complete (judged by the fact that no isocyanate infrared peak is detected by infrared spectrometer), and then the ethyl acetate is removed by reduced pressure distillation to obtain the tackifying resin, which is sealed and stored for later use;

[0042] (3) Preparation of crosslinking resin

[0043] Put 100 parts of polycaprolactone diol into a reactor, heat to 100℃, and distill under reduced pressure (vacuum degree

[0044] ≤-0.098MPa) to a moisture content of less than 0.03%, cool to 65℃, then add 150 parts of ethyl acetate, 117.74 parts of HDI trimer and 0.2 parts of dibutyltin dilaurate, and react until the NCO content is 5.71%. Control the reaction at 0-5℃ by ice bath, and drop 111.18 parts of N-2-aminoethyl-3-aminopropyl trimethoxysilane into the reactor at a dropping speed of 3mL / min under nitrogen protection. After the dropping of the material is completed, slowly warm to 30℃ until the NCO reaction is complete (determined by infrared spectrometer to detect no isocyanate infrared peak), and remove the solvent by reduced pressure distillation to obtain a crosslinked resin, which is sealed and stored for later use.

[0045] (4) Preparation of modified polyurethane resin

[0046] Put 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of tetraisopropyl titanate, and 57.5 parts of ethyl acetate into a ball mill and grind for 8h to obtain a modified polyurethane primer, which is sealed and stored for later use.

[0047] Example 2

[0048] A modified polyurethane primer, prepared from 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of tetraisopropyl titanate, and 57.5 parts of ethyl acetate by weight, wherein the tackifying resin is prepared from polycarbonate diol (PCDL T6001), MDI and hydroxyl-terminated organosilicon modified rosin-based end-capping agent, the hydroxyl-terminated organosilicon modified rosin-based end-capping agent is prepared from 3-(2,3-epoxypropoxy) propyl trimethoxysilane and refined rosin, and the crosslinking resin is prepared from HDI trimer, polycarbonate diol (PCDL T6001) and N-2-aminoethyl-3-aminopropyl trimethoxysilane.

[0049] The preparation of the modified polyurethane primer of the present example comprises:

[0050] (1) Preparation of hydroxyl-terminated organosilicon modified rosin-based end-capping agent

[0051] Put 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.14 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.5 parts of catalyst triethylamine into a reactor, warm to 100℃, and react until the product acid value is less than 5mg KOH / g. Remove the solvent by reduced pressure distillation to obtain the hydroxyl-terminated organosilicon modified rosin-based end-capping agent, which is sealed and stored for later use.

[0052] (2) Preparation of tackifying resin

[0053] 100 parts of polycarbonate diol were placed in a reactor, heated to 100°C, distilled under reduced pressure (vacuum degree

[0054] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 64.66 parts of a hydroxyl-terminated silicone-modified rosin-based end-capping agent were added, and the reaction was carried out until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by reduced pressure distillation to obtain a tackifying resin, which was sealed and stored for later use.

[0055] (3) Preparation of crosslinking resin

[0056] 100 parts of polycarbonate diol were placed in a reactor, heated to 100°C, distilled under reduced pressure (vacuum degree

[0057] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 64.66 parts of a hydroxyl-terminated silicone-modified rosin-based end-capping agent were added, and the reaction was carried out until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by reduced pressure distillation to obtain a tackifying resin, which was sealed and stored for later use.

[0058] (4) Preparation of modified polyurethane resin

[0059] 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of tetraisopropyl titanate, and 57.5 parts of ethyl acetate were placed in a ball mill and ground for 8 h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0060] Example 3

[0061] A modified polyurethane primer is prepared from 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of Elotex carbon black SB250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate, wherein the tackifying resin is obtained by reaction of alkyd polyester diol (DIC OD-X-355), MDI and hydroxyl-terminated organosilicon modified rosin end-capping agent, the hydroxyl-terminated organosilicon modified rosin end-capping agent is obtained by reaction of 3-(2,3-epoxypropoxy)propyl trimethoxysilane and refined rosin, and the crosslinking resin is obtained by reaction of HDI trimer, alkyd polyester diol (DIC OD-X-355) and N-2-aminoethyl-3-aminopropyl trimethoxysilane.

[0062] The preparation of the modified polyurethane primer of the present embodiment comprises:

[0063] (1) Preparation of hydroxyl-terminated organosilicon modified rosin end-capping agent

[0064] 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.14 parts of 3-(2,3-epoxypropoxy)propyl trimethoxysilane and 0.5 parts of catalyst triethylamine are placed in a reactor under nitrogen protection, heated to 100°C, and kept at this temperature until the acid value of the product is less than 5 mg KOH / g, and then the solvent is removed by reduced pressure distillation to obtain the hydroxyl-terminated organosilicon modified rosin end-capping agent, which is sealed and stored for later use;

[0065] (2) Preparation of tackifying resin

[0066] 100 parts of alkyd polyester diol are placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0067] ≤-0.098 MPa) until the moisture content is less than 0.03%, then cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate are added, and the reaction is continued until the NCO content is 1.74%, then 64.66 parts of the hydroxyl-terminated organosilicon modified rosin end-capping agent is added until the NCO reaction is complete (judged by the fact that no isocyanate infrared peak is detected by infrared spectrometer), and then the ethyl acetate is removed by reduced pressure distillation to obtain the tackifying resin, which is sealed and stored for later use;

[0068] (3) Preparation of crosslinking resin

[0069] 100 parts of alkyd polyester diol are placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0070] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 117.74 parts of HDI trimer, and 0.2 parts of dibutyltin dilaurate were added. The reaction was controlled at 0-5°C by ice bath, and 111.18 parts of N-2-aminoethyl-3-aminopropyl trimethoxysilane was added dropwise into the reactor at a dropping speed of 3 mL / min under nitrogen protection. After the material was added, the temperature was slowly increased to 30°C until the NCO reaction was complete (determined by infrared spectrometer to determine that there was no isocyanate infrared peak). The solvent was removed by vacuum distillation to obtain a crosslinked resin, which was sealed and stored for later use.

[0071] (4) Preparation of modified polyurethane resin

[0072] The modified polyurethane primer was prepared by placing 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of tetraisopropyl titanate, and 57.5 parts of ethyl acetate in a ball mill and grinding for 8 h. The modified polyurethane primer was sealed and stored for later use.

[0073] Example 4

[0074] A modified polyurethane primer was prepared by using 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of tetraisopropyl titanate, and 57.5 parts of ethyl acetate as raw materials. The tackifying resin was prepared from alkyd polyester diol (DIC OD-X-355), MDI, and hydroxyl-terminated organosilicon modified rosin-based end-capping agent. The hydroxyl-terminated organosilicon modified rosin-based end-capping agent was prepared from 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane and refined rosin. The crosslinking resin was prepared from HDI trimer, alkyd polyester diol (DIC OD-X-355), and N-2-aminoethyl-3-aminopropyl trimethoxysilane.

[0075] The preparation of the modified polyurethane primer of this example includes:

[0076] (1) Preparation of hydroxyl-terminated organosilicon modified rosin-based end-capping agent

[0077] Under nitrogen protection, 100 parts of refined rosin, 150 parts of dimethylbenzene, 81.3 parts of 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, and 0.5 parts of catalyst triethylamine were placed in a reactor and heated to 100°C. The reaction was carried out until the acid value of the product was less than 5 mg KOH / g. The solvent was removed by vacuum distillation to obtain the hydroxyl-terminated organosilicon modified rosin-based end-capping agent, which was sealed and stored for later use.

[0078] (2) Preparation of tackifying resin

[0079] 100 parts of alkyd polyester diol were placed in a reactor and heated to 100°C under vacuum (vacuum degree 0.095 MPa) until the acid value of the product was less than 5 mg KOH / g. The solvent was removed by vacuum distillation to obtain the tackifying resin, which was sealed and stored for later use.

[0080] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 65.91 parts of a hydroxyl-terminated silicone-modified rosin-based capping agent was added until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by vacuum distillation to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0081] (3) Preparation of a crosslinking resin

[0082] 100 parts of an alkyd polyester diol was placed in a reactor, heated to 100°C under reduced pressure (vacuum degree

[0083] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 65.91 parts of a hydroxyl-terminated silicone-modified rosin-based capping agent was added until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by vacuum distillation to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0084] (4) Preparation of a modified polyurethane resin

[0085] 20 parts of the adhesion-promoting resin, 15 parts of the crosslinking resin, 7 parts of Elotex carbon black SB250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate were ground in a ball mill for 8 h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0086] Example 5

[0087] A modified polyurethane primer, prepared from 20 parts of an adhesion-promoting resin, 15 parts of a crosslinking resin, 7 parts of Elotex carbon black SB250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate, by weight, the adhesion-promoting resin being prepared from an alkyd polyester diol (DIC OD-X-355), MDI and a hydroxyl-terminated silicone-modified rosin-based capping agent, the hydroxyl-terminated silicone-modified rosin-based capping agent being prepared from 3-(2,3-epoxypropoxy)propyl trimethoxysilane and refined rosin, and the crosslinking resin being prepared from triphenylphosphite triisocyanate, an alkyd polyester diol (DIC OD-X-355) and N-2-aminoethyl-3-aminopropyl trimethoxysilane.

[0088] The preparation of the modified polyurethane primer of the present embodiment comprises:

[0089] (1) Preparation of hydroxyl-terminated silicone-modified rosin-based end-capping agent

[0090] Under nitrogen protection, 100 parts of refined rosin, 150 parts of xylene, 78.14 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.5 parts of triethylamine were placed in a reactor, heated to 100°C, and reacted until the product acid value was less than 5 mgKOH / g. The solvent was removed by distillation under reduced pressure to obtain a hydroxyl-terminated silicone-modified rosin-based end-capping agent, which was sealed and stored for later use;

[0091] (2) Preparation of tackifying resin

[0092] 100 parts of alcohol polyester diol were placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0093] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added. The reaction was carried out until the NCO content was 1.74%. 64.66 parts of hydroxyl-terminated silicone-modified rosin-based end-capping agent were added until the NCO reaction was complete (judged by the absence of isocyanate infrared peaks detected by infrared spectrometer). The ethyl acetate was removed by distillation under reduced pressure to obtain a tackifying resin, which was sealed and stored for later use;

[0094] (3) Preparation of crosslinking resin

[0095] 100 parts of alcohol polyester diol were placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0096] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of solvent ethyl acetate, 108.53 parts of triphenylphosphine thio-phosphoric acid triisocyanate and 0.2 parts of dibutyltin dilaurate were added. The reaction was carried out until the NCO content was 5.71%. The reaction was controlled at 0-5°C by ice bath. Under nitrogen protection, 111.3 parts of N-2-aminoethyl-3-aminopropyl trimethoxysilane was added into the reactor at a dropping speed of 3 mL / min. After the material was added, the temperature was slowly raised to 30°C until the NCO reaction was complete (judged by the absence of isocyanate infrared peaks detected by infrared spectrometer). The solvent was removed by distillation under reduced pressure to obtain a crosslinking resin, which was sealed and stored for later use.

[0097] (4) Preparation of modified polyurethane resin

[0098] 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of titanium tetraisopropylate, 57.5 parts of ethyl acetate were placed in a ball mill and ground for 8h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0099] Example 6

[0100] A modified polyurethane primer, the raw materials for preparation include 20 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate by weight fraction, the tackifying resin is prepared by alkyd polyester diol (DIC OD-X-355), MDI and hydroxyl-terminated organosilicon modified rosin-based end-capping agent, the hydroxyl-terminated organosilicon modified rosin-based end-capping agent is prepared by 3-(2,3-epoxypropoxy) propyl trimethoxysilane and refined rosin, and the crosslinking resin is prepared by triphenylmethane triisocyanate, alkyd polyester diol (DIC OD-X-355) and N-2-aminoethyl-3-aminopropyl trimethoxysilane.

[0101] The preparation of the modified polyurethane primer of the present embodiment includes:

[0102] (1) Preparation of hydroxyl-terminated organosilicon modified rosin-based end-capping agent

[0103] Under nitrogen protection, 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.14 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.5 parts of catalyst triethylamine were placed in a reactor, heated to 100°C, and reacted until the acid value of the product was less than 5 mg KOH / g, and the solvent was removed by vacuum distillation to obtain the hydroxyl-terminated organosilicon modified rosin-based end-capping agent, which was sealed and stored for later use;

[0104] (2) Preparation of tackifying resin

[0105] 100 parts of alkyd polyester diol were placed in a reactor, heated to 100°C under reduced pressure (vacuum degree

[0106] ≤-0.098 MPa) to distill until the moisture content was less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was continued until the NCO content was 1.74%, 64.66 parts of hydroxyl-terminated organosilicon modified rosin-based end-capping agent was added, and the NCO reaction was complete (judged by infrared spectrometer to detect no isocyanate infrared peak), and the ethyl acetate was removed by vacuum distillation to obtain the tackifying resin, which was sealed and stored for later use;

[0107] (3) Preparation of crosslinking resin

[0108] 100 parts of alkyd polyester diol were placed in a reactor, heated to 100°C under reduced pressure (vacuum degree

[0109] distillation to moisture content less than 0.03%, cooling to 65℃, then adding 150 parts of ethyl acetate, 85.74 parts of triphenylmethane triisocyanate and 0.2 parts of dibutyltin dilaurate, reacting until the NCO content is 5.71%, controlling the reaction at 0-5℃ by ice bath, under nitrogen protection, adding 111.29 parts of N-2-aminoethyl-3-aminopropyl trimethoxysilane into the reactor at a dropping speed of 3mL / min, slowly warming to 30℃ until the NCO reaction is complete (judged by infrared spectrometer to detect no isocyanate infrared peak), removing the solvent by vacuum distillation to obtain the crosslinked resin, which is sealed for storage.

[0110] (4) Preparation of modified polyurethane resin

[0111] Placing 20 parts of tackifying resin, 15 parts of crosslinked resin, 7 parts of carbon black SB250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate in a ball mill for grinding for 8h to obtain a modified polyurethane primer, which is sealed for storage.

[0112] Example 7

[0113] A modified polyurethane primer, prepared from 20 parts of tackifying resin, 15 parts of crosslinked resin, 7 parts of carbon black SB250, 0.5 parts of tetraisopropyl titanate and 57.5 parts of ethyl acetate by weight, wherein the tackifying resin is prepared from alkyd polyester diol (DIC OD-X-355), MDI and hydroxyl-terminated silicone-modified rosin-based end-capping agent, the hydroxyl-terminated silicone-modified rosin-based end-capping agent is prepared from 3-(2,3-epoxypropoxy)propyl trimethoxysilane and refined rosin, and the crosslinked resin is prepared from HDI trimer, alkyd polyester diol (DIC OD-X-355) and 3-diethylenetriamine propyl trimethoxysilane.

[0114] The preparation of the modified polyurethane primer of the present example comprises:

[0115] (1) Preparation of hydroxyl-terminated silicone-modified rosin-based end-capping agent

[0116] Placing 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.14 parts of 3-(2,3-epoxypropoxy)propyl trimethoxysilane and 0.5 parts of catalyst triethylamine in a reactor, warming to 100℃, and reacting until the acid value of the product is less than 5mg KOH / g, and removing the solvent by vacuum distillation to obtain the hydroxyl-terminated silicone-modified rosin-based end-capping agent, which is sealed for storage;

[0117] (2) Preparation of tackifying resin

[0118] Placing 100 parts of alkyd polyester diol in a reactor, heating to 100℃ under vacuum (vacuum degree 0.08MPa), and adding 0.098 parts of 4,4'-diphenylmethane diisocyanate dropwise, and reacting until the NCO content is 5.71%, distilling to moisture content less than 0.03%, cooling to 65℃, then adding 150 parts of ethyl acetate, 85.74 parts of triphenylmethane triisocyanate and 0.2 parts of dibutyltin dilaurate, reacting until the NCO content is 5.71%, controlling the reaction at 0-5℃ by ice bath, under nitrogen protection, adding 111.29 parts of N-2-aminoethyl-3-aminopropyl trimethoxysilane into the reactor at a dropping speed of 3mL / min, slowly warming to 30℃ until the NCO reaction is complete (judged by infrared spectrometer to detect no isocyanate infrared peak), removing the solvent by vacuum distillation to obtain the crosslinked resin, which is sealed for storage.

[0119] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 64.66 parts of a hydroxyl-terminated silicone-modified rosin-based capping agent was added until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by vacuum distillation to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0120] (3) Preparation of a crosslinking resin

[0121] 100 parts of an alkyd polyester diol was placed in a reactor, heated to 100°C under reduced pressure (vacuum degree

[0122] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 64.66 parts of a hydroxyl-terminated silicone-modified rosin-based capping agent was added until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by vacuum distillation to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0123] (4) Preparation of a modified polyurethane resin

[0124] 20 parts of the adhesion-promoting resin, 15 parts of the crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of tetraisopropyl titanate, and 57.5 parts of ethyl acetate were ground in a ball mill for 8 h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0125] Example 8

[0126] A modified polyurethane primer, prepared from the following raw materials in parts by weight, includes 25 parts of an adhesion-promoting resin, 15 parts of a crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of dibutyltin diacetate, and 52.5 parts of butanone. The adhesion-promoting resin is prepared from an alkyd polyester diol (DIC OD-X-355), MDI, and a hydroxyl-terminated silicone-modified rosin-based capping agent, which is prepared from 3-(2,3-epoxypropoxy)propyl trimethoxysilane and refined rosin. The crosslinking resin is prepared from an HDI trimer, an alkyd polyester diol (DIC OD-X-355), and 3-diethylenetriaminylpropyl trimethoxysilane.

[0127] The preparation of the modified polyurethane primer of this example includes:

[0128] (1) Preparation of hydroxyl-terminated silicone-modified rosin-based end-capping agent

[0129] Under nitrogen protection, 100 parts of refined rosin, 150 parts of xylene, 77.93 parts of 3-(2,3-epoxypropoxy)propyl trimethoxysilane and 0.5 parts of catalyst triethylamine were placed in a reactor, heated to 100°C, and reacted until the product acid value was less than 5 mg KOH / g. The solvent was removed by distillation under reduced pressure to obtain a hydroxyl-terminated silicone-modified rosin-based end-capping agent, which was sealed and stored for later use.

[0130] (2) Preparation of tackifying resin

[0131] 100 parts of alcohol polyester diol were placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0132] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added. The reaction was carried out until the NCO content was 1.74%. 64.66 parts of hydroxyl-terminated silicone-modified rosin-based end-capping agent were added until the NCO reaction was complete (judged by the absence of isocyanate infrared peaks detected by infrared spectrometer). The ethyl acetate was removed by distillation under reduced pressure to obtain a tackifying resin, which was sealed and stored for later use.

[0133] (3) Preparation of crosslinking resin

[0134] 100 parts of alcohol polyester diol were placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0135] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added. The reaction was carried out until the NCO content was 1.74%. 64.66 parts of hydroxyl-terminated silicone-modified rosin-based end-capping agent were added until the NCO reaction was complete (judged by the absence of isocyanate infrared peaks detected by infrared spectrometer). The ethyl acetate was removed by distillation under reduced pressure to obtain a tackifying resin, which was sealed and stored for later use.

[0136] (4) Preparation of modified polyurethane resin

[0137] 25 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of dibutyltin diacetate, 52.5 parts of acetone were placed in a ball mill and ground for 8h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0138] Example 9

[0139] A modified polyurethane primer, the preparation raw materials include 15 parts of tackifying resin, 25 parts of crosslinking resin, 5 parts of carbon black SB250, 0.5 parts of dibutyl tin diacetate and 54.5 parts of butanone by weight fraction, the tackifying resin is prepared by alkyd polyester diol (DIC OD-X-355), MDI and hydroxyl-terminated organosilicon modified rosin-based end-capping agent, the hydroxyl-terminated organosilicon modified rosin-based end-capping agent is prepared by 3-(2,3-epoxypropoxy) propyl trimethoxysilane and refined rosin, and the crosslinking resin is prepared by HDI trimer, alkyd polyester diol (DIC OD-X-355) and 3-diethylenetriamine propyl trimethoxysilane.

[0140] The preparation of the modified polyurethane primer of the embodiment includes:

[0141] (1) Preparation of hydroxyl-terminated organosilicon modified rosin-based end-capping agent

[0142] Under the protection of nitrogen, 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.14 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.5 parts of catalyst triethylamine are placed in a reactor, heated to 100°C, and kept at 100°C until the product acid value is less than 5 mg KOH / g, and the solvent is removed by vacuum distillation to obtain the hydroxyl-terminated organosilicon modified rosin-based end-capping agent, which is sealed and stored for later use;

[0143] (2) Preparation of tackifying resin

[0144] 100 parts of alkyd polyester diol are placed in a reactor, heated to 100°C and vacuum distilled until the moisture content is less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate are added, and the reaction is carried out until the NCO content is 1.74%, then 64.66 parts of hydroxyl-terminated organosilicon modified rosin-based end-capping agent is added until the NCO reaction is complete (judged by infrared spectrometer detection of no isocyanate infrared peak), and the ethyl acetate is removed by vacuum distillation to obtain the tackifying resin, which is sealed and stored for later use;

[0145] (3) Preparation of crosslinking resin

[0146] Put 100 parts of alkyd polyester diol in the reactor, heat to 100°C, reduce pressure distillation to moisture content less than 0.03%, cool to 65°C, then add 150 parts of solvent ethyl acetate, 117.74 parts of HDI trimer and 0.2 parts of catalyst dibutyltin dilaurate, react until the NCO content is 5.71%, control the reaction at 0-5°C by ice bath, under the protection of nitrogen, drop 132.81 parts of 3-diethylenetriamine propyl trimethoxysilane into the reactor at a drop rate of 3mL / min, slowly warm to 30°C until the NCO reaction is complete (determined by infrared spectrometer that there is no isocyanate infrared peak), remove the solvent by reduced pressure distillation, obtain the crosslinking resin, seal and save for later use.

[0147] (4) Preparation of modified polyurethane resin

[0148] Put 15 parts of tackifying resin, 25 parts of crosslinking resin, 5 parts of carbon black SB250, 0.5 parts of dibutyltin diacetate and 54.5 parts of acetone in a ball mill and grind for 8h to obtain a modified polyurethane primer, seal and save for later use.

[0149] Example 10

[0150] A modified polyurethane primer, the preparation raw materials include 20 parts of tackifying resin, 20 parts of crosslinking resin, 9 parts of carbon black SB250, 1 part of titanium isopropyl titanate and 50 parts of butanone by weight fraction, the tackifying resin is prepared from alkyd polyester diol (DICOD-X-355), MDI and hydroxyl-terminated silicone modified rosin-based end-capping agent, the hydroxyl-terminated silicone modified rosin-based end-capping agent is prepared from 3-(2,3-epoxypropoxy) propyl trimethoxysilane and refined rosin, and the crosslinking resin is obtained by reaction of HDI trimer, alkyd polyester diol (DICOD-X-355) and 3-diethylenetriamine propyl trimethoxysilane.

[0151] The preparation of the modified polyurethane primer of the present example includes:

[0152] (1) Preparation of hydroxyl-terminated silicone modified rosin-based end-capping agent

[0153] Put 100 parts of refined rosin, 150 parts of dimethylbenzene, 78.03 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.5 parts of catalyst triethylamine in the reactor, warm to 100°C, and react until the product acid value is less than 5mg KOH / g, remove the solvent by reduced pressure distillation to obtain the hydroxyl-terminated silicone modified rosin-based end-capping agent, seal and save for later use;

[0154] (2) Preparation of tackifying resin

[0155] 100 parts of alkyd polyester diol were placed in a reactor, heated to 100°C, distilled under reduced pressure to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, then 64.66 parts of a hydroxyl-terminated silicone-modified rosin-based end-capping agent were added until the NCO reaction was complete (determined by infrared spectrometer detection of no isocyanate infrared peak), and the ethyl acetate was removed by reduced pressure distillation to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0156] (3) Preparation of crosslinking resin

[0157] 100 parts of alkyd polyester diol were placed in a reactor, heated to 100°C, distilled under reduced pressure to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of solvent ethyl acetate, 117.89 parts of HDI trimer and 0.2 parts of catalyst dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 5.71%, the reaction was controlled at 0-5°C by ice bath, 132.98 parts of 3-diethylenetriamine propyl trimethoxysilane was added into the reactor at a dropping speed of 3mL / min under nitrogen protection, after the material was added, the temperature was slowly raised to 30°C, until the NCO reaction was complete (determined by infrared spectrometer detection of no isocyanate infrared peak), and the solvent was removed by reduced pressure distillation to obtain a crosslinking resin, which was sealed and stored for later use.

[0158] (4) Preparation of modified polyurethane resin

[0159] 20 parts of adhesion-promoting resin, 20 parts of crosslinking resin, 9 parts of carbon black SB250, 1 part of titanium tetraisopropylate, and 50 parts of acetone were placed in a ball mill and ground for 8h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0160] Comparative Example 1

[0161] A modified polyurethane primer, prepared from 25 parts of adhesion-promoting resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of dibutyltin diacetate and 52.5 parts of butanone, the adhesion-promoting resin was prepared from alkyd polyester diol (DIC OD-X-355), MDI and N-phenyl-3-aminopropyl trimethoxysilane, and the crosslinking resin was prepared from HDI trimer, alkyd polyester diol (DIC OD-X-355) and 3-diethylenetriamine propyl trimethoxysilane.

[0162] The preparation of the modified polyurethane primer of the present comparative example includes:

[0163] (1) Preparation of adhesion-promoting resin

[0164] 100 parts of alkyd polyester diol were placed in a reactor, heated to 100°C, distilled under reduced pressure (vacuum degree

[0165] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 30.65 parts of N-phenyl-3-aminopropyl trimethoxysilane was added until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by distillation under reduced pressure to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0166] (3) Preparation of a crosslinking resin

[0167] 100 parts of the alkyd polyester diol was placed in a reactor, heated to 100°C under reduced pressure (vacuum degree

[0168] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added, and the reaction was carried out until the NCO content was 1.74%, 30.65 parts of N-phenyl-3-aminopropyl trimethoxysilane was added until the NCO reaction was complete (judged by the fact that no isocyanate infrared peak was detected by an infrared spectrometer), and the ethyl acetate was removed by distillation under reduced pressure to obtain an adhesion-promoting resin, which was sealed and stored for later use;

[0169] (4) Preparation of a modified polyurethane primer

[0170] 25 parts of the adhesion-promoting resin, 15 parts of the crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of dibutyltin diacetate and 52.5 parts of acetone were ground in a ball mill for 8 h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0171] Comparative Example 2

[0172] A modified polyurethane primer, prepared from 25 parts of an adhesion-promoting resin, 15 parts of a crosslinking resin, 7 parts of Elastopan carbon black SB250, 0.5 parts of dibutyltin diacetate and 52.5 parts of acetone, by weight, the adhesion-promoting resin being prepared from alkyd polyester diol (DIC OD-X-355), MDI and a hydroxyl-terminated organosilicon-modified rosin-based capping agent, the hydroxyl-terminated organosilicon-modified rosin-based capping agent being prepared from 3-(2,3-epoxypropoxy)propyl trimethoxysilane and refined rosin, and the crosslinking resin being prepared from HDI trimer, alkyd polyester diol (DIC OD-X-355) and bis(gamma-trimethoxysilylpropyl)amine.

[0173] The preparation of the modified polyurethane primer of the present comparative example comprises:

[0174] (1) Preparation of hydroxyl-terminated silicone-modified rosin-based end-capping agent

[0175] Under nitrogen protection, 100 parts of refined rosin, 150 parts of dimethylbenzene, 77.93 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.5 parts of catalyst triethylamine were placed in a reactor, heated to 100°C, and reacted until the product acid value was less than 5 mg KOH / g. The solvent was removed by distillation under reduced pressure to obtain a hydroxyl-terminated silicone-modified rosin-based end-capping agent, which was sealed and stored for later use.

[0176] (2) Preparation of tackifying resin

[0177] 100 parts of alcohol polyester diol were placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0178] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added. The reaction was carried out until the NCO content was 1.74%. 64.66 parts of hydroxyl-terminated silicone-modified rosin-based end-capping agent were added until the NCO reaction was complete (judged by the absence of isocyanate infrared peaks detected by infrared spectrometer). The ethyl acetate was removed by distillation under reduced pressure to obtain a tackifying resin, which was sealed and stored for later use.

[0179] (3) Preparation of crosslinking resin

[0180] 100 parts of alcohol polyester diol were placed in a reactor, heated to 100°C and distilled under reduced pressure (vacuum degree

[0181] ≤-0.098 MPa) to a moisture content of less than 0.03%, cooled to 65°C, and then 150 parts of ethyl acetate, 40 parts of MDI and 0.2 parts of dibutyltin dilaurate were added. The reaction was carried out until the NCO content was 1.74%. 64.66 parts of hydroxyl-terminated silicone-modified rosin-based end-capping agent were added until the NCO reaction was complete (judged by the absence of isocyanate infrared peaks detected by infrared spectrometer). The ethyl acetate was removed by distillation under reduced pressure to obtain a tackifying resin, which was sealed and stored for later use.

[0182] (4) Preparation of modified polyurethane resin

[0183] 25 parts of tackifying resin, 15 parts of crosslinking resin, 7 parts of carbon black SB250, 0.5 parts of dibutyltin diacetate, 52.5 parts of acetone were placed in a ball mill and ground for 8h to obtain a modified polyurethane primer, which was sealed and stored for later use.

[0184] The modified polyurethane primer prepared in Examples 1-10 and Comparative Examples 1-2 (hereinafter referred to as primer) and a commercially available primer were tested for surface dry time, peel adhesion, tensile shear, shelf life, aging resistance, low temperature adhesion, and low temperature initial adhesion, and the test conditions and methods were as follows:

[0185] (1) Surface dry time: tested according to "GB / T 13477.5 2002 Test methods for building sealants".

[0186] (2) Peel adhesion: tested according to "DVS 1618 2002 Elastic thick film adhesion in rail vehicles".

[0187] The specific implementation steps are as follows: first, the surface of the substrate is thoroughly cleaned with a cleaning agent, and after drying, a layer of primer is uniformly applied to the surface of the substrate using a brush, and after the primer is completely dry, five strips of polyurethane adhesive tape with a width of about 10 mm and a length of at least 50 mm are applied to the surface of the substrate using a glue gun, and the substrate with the applied adhesive tape is placed in a standard state (23°C / 50% RH) for 7 days; after 7 days of curing, the adhesive tape is cut to the adhesive surface with a knife, and the adhesive tape is peeled off with tweezers (peeling angle 130-160°), and during the peeling process, the adhesive tape is cut to the adhesive surface every 510 mm in the transverse direction, with a cutting interval of about 3 seconds, and the material is continuously subjected to a load, and the test length is at least 50 mm, wherein the test sample is a non-self-adhesive two-component polyurethane adhesive with a shear strength of about 6.0 MPa.

[0188] (3) Tensile shear: tested according to "GB / T 7124 2008 Determination of tensile shear strength of adhesives (rigid material to rigid material)".

[0189] (4) Shelf life: the freshly prepared primer was placed at 40°C for 1 month, 3 months, 6 months, 9 months, and 12 months, respectively, and the peel adhesion of the polyurethane adhesive and the primer on the black edge glass surface was tested according to the above method.

[0190] (5) Aging resistance: tested according to "QC / T 1024 2015 Single-component polyurethane sealant for automobiles".

[0191] (6) Low temperature adhesion: according to the test method of peel adhesion, the samples were placed in an environment of 0°C for 1h, 2h, 4h, and 8h, respectively, and the peel adhesion was observed.

[0192] (7) Low temperature initial adhesion: samples were prepared according to the above tensile shear method, and the samples were placed in an environment of 0°C for 1h, 2h, 4h, and 8h, respectively, and the cohesive failure of the primer and the substrate and the two-component polyurethane adhesive was observed.

[0193] The base coating agents prepared in Examples 1-10 and Comparative Examples 1-2 and some commercially available base coating agents were subjected to tests of surface dry time, peel adhesion, tensile shear, shelf life, aging resistance, low temperature adhesion, and low temperature tack, with no base coating agent applied as a blank test. The results are shown in Table 1 below.

[0194] Table 1

[0195]

[0196]

[0197] Table 1 (continued)

[0198]

[0199]

[0200] As can be seen from Table 1, the base coating agents prepared in Examples 1-10 all have good low temperature adhesion and low temperature tack under low temperature conditions, and are very suitable for use in cold winter environments, and can significantly shorten the fixture removal time in the main engine plant and the rapid driving-off time in the after-sales market. The commercially available base coating agents have poor low temperature performance, and when used in conjunction with the two-component polyurethane adhesive that is cured as a whole under low temperature conditions, the base coating agent and the sample adhesive and the substrate fall off, and are not suitable for use in fast-paced production lines and the after-sales market rapid driving-off. The base coating agent of the present application has good low temperature adhesion and low temperature tack compared to Comparative Examples 1 and 2 and conventional commercially available base coating agents. The main reason is that the rosin tricyclic phenanthrene skeleton structure in the base coating agent has excellent low temperature performance and adhesion. The crystallizability of the rosin structure in the tackifying resin under low temperature conditions causes the base coating agent to quickly wet and adsorb the surface of the adherend substrate, forming a preliminary adhesion effect. At the same time, the amine groups remaining in the side groups of the crosslinking resin and the isocyanate groups in the polyurethane adhesive still have high reactivity under low temperature conditions, allowing the adhesive and the base coating agent to quickly form a chemical bond.

[0201] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, it is not limited to the examples listed in the embodiments. Those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A modified polyurethane primer characterized in that, The raw materials are prepared by 15-25 parts of tackifying resin, 15-25 parts of crosslinking resin, 5-9 parts of pigment carbon black, 0.5-1.0 parts of catalyst and 50-60 parts of solvent by weight, wherein the tackifying resin is obtained by reaction of first polyester diol, diisocyanate and hydroxyl-terminated silicone modified rosin end-capping agent, the hydroxyl-terminated silicone modified rosin end-capping agent is obtained by reaction of epoxy silane and rosin, and the crosslinking resin is obtained by reaction of triisocyanate, second polyester diol and polyamino silane.

2. The modified polyurethane primer of claim 1, wherein, The epoxy silane is at least one selected from 3-(2,3-epoxypropoxy)propyl trimethoxysilane, 3-(2,3-epoxypropoxy)propyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane.

3. The modified polyurethane primer of claim 1, wherein, The rosin is at least one selected from hydrogenated rosin, dehydroabietic acid and refined rosin.

4. The modified polyurethane primer of claim 1, wherein, The diisocyanate is at least one selected from MDI, HDI, TDI and IPDI.

5. The modified polyurethane primer of claim 1, wherein, The triisocyanate is at least one selected from HDI trimer, IPDI trimer, TDI trimer, thiophosphoric acid triphenyl triisocyanate and triphenyl methane triisocyanate.

6. The modified polyurethane primer of claim 1, wherein, The polyamino silane is at least one selected from N-2-aminoethyl-3-aminopropyl triethoxysilane, N-2-aminoethyl-3-aminopropyl trimethoxysilane, 3-diethylenetriamine propyl trimethoxysilane, N-benzyl-N'-[3-(trimethoxysilyl)propyl] ethylenediamine hydrochloride and vinyl benzyl aminoethyl aminopropyl trimethoxysilane hydrochloride.

7. The modified polyurethane primer of claim 1, wherein, The first polyester diol and the second polyester diol are each independently at least one selected from polycarbonate diol, polycaprolactone diol and alkyd polyester diol, and the molecular weight of the first polyester diol and the second polyester diol is 1000-2000.

8. The modified polyurethane primer of claim 1, wherein, The catalyst is at least one selected from organic tin catalyst and titanate catalyst.

9. The modified polyurethane primer of claim 1, wherein, The solvent is at least one selected from ethyl acetate, butyl acetate, acetone, butanone and xylene.

10. The method of preparing a modified polyurethane primer according to any one of claims 1 to 9, characterized in that, It comprises: (1) preparation of hydroxyl-terminated silicone modified rosin end-capping agent The rosin, the epoxy silane, triethylamine and the solvent are placed in a reactor under a protective atmosphere, and reacted at 100-105℃ until the acid value of the reaction solution is less than 5mg KOH / g, and the hydroxyl-terminated silicone modified rosin end-capping agent is obtained after post-treatment, wherein the molar ratio of epoxy groups in the epoxy silane to carboxyl groups in the rosin is 1:1; (2) preparation of tackifying resin The diisocyanate, the solvent, organic tin catalyst and the first polyester diol after dehydration are placed in a reactor, and reacted until NCO reaches the theoretical value, then the hydroxyl-terminated silicone modified rosin end-capping agent is added until NCO reaction is complete, and the tackifying resin is obtained after post-treatment; (3) preparation of crosslinking resin The triisocyanate, the solvent, the organic tin catalyst and the dehydrated second polyester diol are placed in a reactor, and the reaction is carried out until NCO reaches the theoretical value, then the polyamino silane is dropped into the reactor at 0-5 DEG C under a protective atmosphere, after dropping is completed, the temperature is slowly increased to 25-35 DEG C, until NCO reaction is complete, and the crosslinked resin is obtained after post-treatment; (4) Preparation of modified polyurethane primer The tackifying resin, the crosslinked resin, the pigment carbon black, the catalyst and the solvent are mixed uniformly.

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