Polyurethane glass primer and preparation method thereof

Abstract

The invention belongs to the technical field of primer, and particularly relates to a polyurethane glass primer and a preparation method thereof. The polyurethane glass primer is prepared from the following components in parts by weight: 20 to 40 parts of silane modified polyurethane prepolymer, 1 to 5 parts of adhesion promoter, 1 to 10 parts of carbon black, 1 to 2 parts of dispersing agent, 50 to 150 parts of quick-drying solvent, 10 to 50 parts of slow-drying solvent and 0.05 to 0.5 part of surface drying catalyst, 1-2 parts of a water removal agent; the silane modified polyurethane prepolymer is a polyurethane prepolymer obtained by polymerizing polyhydric alcohol and polyisocyanate in the presence of a polymerization catalyst and then blocking the polyhydric alcohol and the polyisocyanate through a silane coupling agent. When the primer disclosed by the invention is used, relatively high bonding strength between a polyurethane edge covering material and skylight glass can be ensured, the peeling strength is high, and meanwhile, the primer also has the characteristics that the solid content is low (lt); 30%), short surface drying time (rapid surface drying and film forming), and long storage time.

Description

Technical Field

[0001] The invention belongs to the technical field of primers, and in particular relates to a polyurethane glass primer for bonding automobile skylight glass and polyurethane edge wrapping materials and a preparation method thereof. Background Art

[0002] The automotive glass edge molding process refers to the process of coating the edge surface of the glass with polyurethane. Before the edge molding, the primer needs to be applied to the surface of the glass substrate in advance. After curing, a layer of resin film is formed on the surface of the substrate, which serves the purpose of modifying the surface of the substrate, thereby significantly improving the adhesion between the edge material and the substrate.

[0003] After the primer and polyurethane sealant or hemming material are applied in sequence, a 90° peeling test with the substrate is required to measure the peeling strength of the material after the primer is applied. During the peeling test, the polyurethane sealant breaks, which shows the strength of the polyurethane sealant itself. The larger the value, the better the bonding effect. However, the polyurethane primer contains active groups NCO and urethane bonds. The active groups will self-polymerize in the presence of the catalyst added to the system, resulting in poor storage stability of the synthesized primer, which limits its service life. At the same time, small-dose packaging will increase packaging costs.

[0004] For example, patent document CN106752838A discloses a polyurethane sealant primer, which has excellent resistance to moisture and heat aging; patent document CN102516921A discloses a preparation method, which uses silane modification and end-capping to achieve a polyurethane glass primer with an NCO content of 0%, and the prepared primer has a longer open time; patent document CN103113819A discloses a polyurethane sealant primer, which has a shorter surface drying and curing time. The primers disclosed in these prior arts are used for bonding polyurethane edging materials to skylight glass, and the bonding effect is not satisfactory. In addition, the solid content of these primers is generally high (all above 30%), which will result in higher production costs.

[0005] Patent document CN113402963A discloses a method for preparing a polyurethane glass primer, and the obtained glass primer has good viscosity-increasing effect and low solid content; patent document CN115322670A discloses a method for preparing a polyurethane glass primer, and the glass primer also contains a nano-composite material; the glass primers prepared by the above existing patents have the advantages of low solid content and strong adhesion, but none of them involve the investigation of the storage stability of the primer.

[0006] In view of this, how to ensure that the obtained glass primer has low solid content, high adhesion and excellent storage stability is a direction worthy of further research. Summary of the invention

[0007] The purpose of the present invention is to provide a polyurethane glass primer and a preparation method thereof, in view of some technical problems existing in the prior art for preparing glass primers. When the prepared primer is used in combination with a polyurethane glass sealant or an edge coating material, it can ensure that the polyurethane edge coating material and the sunroof glass have a high bonding strength and a high peel strength. At the same time, the primer also has the advantages of low solid content (<30%), short surface drying time (rapid surface drying film formation), and long storage time. In addition, its formula mainly uses environmentally friendly solvents, which can better adapt to the production conditions of automobile sunroofs.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] In a first aspect, a polyurethane glass primer is provided, comprising the following components in parts by weight:

[0010] Silane modified polyurethane prepolymer, 20-40 parts (e.g., 22 parts, 24 parts, 25 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 35 parts, 36 parts, 38 parts),

[0011] Adhesion promoter, 1-5 parts (e.g., 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts),

[0012] Carbon black, 1-10 parts (e.g., 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 8 parts),

[0013] Dispersant, 1-2 parts (e.g., 1.2 parts, 1.5 parts, 1.8 parts),

[0014] Quick-drying solvent, 50-150 parts (e.g., 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts),

[0015] Slow drying solvent, 10-50 parts (for example, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 18 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts),

[0016] Table dry catalyst, 0.05-0.5 parts (e.g., 0.06 parts, 0.08 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.4 parts, 0.45 parts);

[0017] Dewatering agent, 1-2 parts (e.g., 1.2 parts, 1.5 parts, 1.8 parts);

[0018] The silane-modified polyurethane prepolymer is a polyurethane prepolymer obtained by polymerizing polyol and polyisocyanate in the presence of a polymerization catalyst and then end-capping the prepolymer with a silane coupling agent.

[0019] In some embodiments, the amounts of the various reaction raw materials of the polyurethane prepolymer are as follows:

[0020] Polyol, 5-100 parts by weight (e.g., 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 80 parts by weight);

[0021] Polyisocyanate, 50-150 parts by weight (e.g., 55 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 90 parts by weight, 100 parts by weight, 110 parts by weight, 120 parts by weight, 130 parts by weight, 140 parts by weight, 145 parts by weight);

[0022] A polymerization catalyst, 0.01-0.05 parts by weight (e.g., 0.015 parts by weight, 0.02 parts by weight, 0.025 parts by weight, 0.03 parts by weight, 0.035 parts by weight, 0.04 parts by weight, 0.045 parts by weight);

[0023] Silane coupling agent, 5-30 parts by weight (e.g., 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 15 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 25 parts by weight, 28 parts by weight).

[0024] According to the polyurethane glass primer provided by the present invention, in some embodiments, the preparation method of the silane-modified polyurethane prepolymer comprises the following steps:

[0025] 5-100 parts by weight of polyol and 50-150 parts by weight of polyisocyanate are mixed, reacted at 40-60° C. (e.g., 45° C., 50° C., 55° C.) for 10-60 min (e.g., 15 min, 20 min, 25 min, 30 min, 40 min, 45 min, 50 min), then 0.01-0.05 parts by weight of polymerization catalyst is added, and the reaction is continued at 60-110° C. (e.g., 65° C., 70° C., 80° C., 90° C., 100° C., 105° C.) for 6-12 h (e.g., , 7h, 8h, 9h, 10h, 11h); when the NCO content in the test system is 6-15wt% (for example, 7wt%, 8wt%, 10wt%, 12wt%, 14wt%), 5-30 parts by weight of silane coupling agent are added to the system, and the reaction is carried out at 60-110°C for 2-5h (for example, 3h, 4h), and the reaction is stopped when the NCO content in the test system is 4-10wt% (for example, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%), to obtain the silane-modified polyurethane prepolymer.

[0026] In some embodiments, in the method for preparing the silane-modified polyurethane prepolymer, the polyol is selected from dipropylene glycol, diethylene glycol, neopentyl glycol, 1,5-pentanediol, and at least one of a polyether polyol or polyester polyol having a functionality of 2 and a molecular weight of 200-2000 (e.g., 300, 400, 500, 800, 1000, 1200, 1400, 1500, 1600, 1800).

[0027] In some embodiments, in the method for preparing the silane-modified polyurethane prepolymer, the polyisocyanate is an isocyanate polymer, preferably selected from at least one of hexamethylene diisocyanate polymer, isophorone diisocyanate biuret, isophorone diisocyanate polymer, hydrogenated phenylmethane diisocyanate polymer or hydrogenated phenylmethane diisocyanate biuret, and more preferably hexamethylene diisocyanate polymer.

[0028] In the present invention, for example, the polyisocyanate may be a combination of a hexamethylene diisocyanate polymer and a hydrogenated phenylmethane diisocyanate polymer or a combination of a hexamethylene diisocyanate polymer and an isophorone diisocyanate polymer.

[0029] In the present invention, the polyisocyanate is commercially available, for example, it can be selected from HT-600 product, HT-300 product, HT-100 product, HT-500 product, HT-400 product and HB-200 product of Wanhua Chemical Company.

[0030] In some embodiments, in the method for preparing the silane-modified polyurethane prepolymer, the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane and bis[3-(trimethoxysilyl)propyl]amine.

[0031] Herein, the end-capping rate of silane in the silane-modified polyurethane prepolymer can be reflected by the NCO content in the prepolymer.

[0032] In some embodiments, in the preparation method of the silane-modified polyurethane prepolymer, the polymerization catalyst is selected from at least one of di(dodecylthio)dibutyltin, dialkyltin dimaleate, dialkyltin dithiolate (such as dibutyltin dithiolate), alkylthiodibutyltin, dibutyltin dimercaptoacetate, dioctyltin dimercaptoacetate, dioctyltin mercaptan (UL-32), bismuth octanoate, bismuth isooctanoate and bismuth carboxylate.

[0033] According to the polyurethane glass primer provided by the present invention, in some embodiments, the surface drying catalyst is selected from at least one of N-(dimethylaminoethyl)morpholine, dimorpholine triethyl ether (DMEEG), N-ethylmorpholine, bismorpholine diethyl ether (DMDEE) and bisdimethylaminoethyl ether, preferably selected from dimorpholine triethyl ether (DMEEG) or bismorpholine diethyl ether (DMDEE).

[0034] In some embodiments, the polymerization catalyst and the surface-drying catalyst are of different types.

[0035] According to the polyurethane glass primer provided by the present invention, in some embodiments, the quick-drying solvent is an environmentally friendly hydrofluoroolefin, or a composite mixture of an environmentally friendly hydrofluoroolefin and a ketone organic solvent;

[0036] In some embodiments, the ketone organic solvent is selected from acetone, butanone, isobutyl ketone, and cyclohexanone;

[0037] In some embodiments, the environmentally friendly hydrofluoroolefin is selected from one or more of trans-chlorotrifluoropropene, pentafluoropropane, 1,1,1,3-tetrafluoropropene and cis-1-chloro-3,3,3-trifluoropropene.

[0038] In some embodiments, the quick-drying solvent is a mixture of at least one of the environmentally friendly hydrofluoroolefins and acetone or butanone.

[0039] According to the polyurethane glass primer provided by the present invention, in some embodiments, the slow-drying solvent is selected from at least one of methylcyclohexane and ethylene glycol diacetate, preferably methylcyclohexane.

[0040] In some embodiments, the mass ratio of the slow-drying solvent to the fast-drying solvent is 1:1 to 1:9, for example, 1:2, 1:3, 1:4, 1:5, 1:6, 1:8.

[0041] According to the polyurethane glass primer provided by the present invention, in some embodiments, the adhesion promoter is a silane coupling agent containing an epoxy group in its molecular structure, preferably selected from at least one of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0042] In some embodiments, the carbon black is selected from at least one of Orion's U carbon, Orion's 49L, and Orion's XPB-756.

[0043] In some embodiments, the dispersant is at least one of the polyurethane coating dispersants; the main function of the dispersant is to improve the dispersion of the toner and prevent flocculation; in this article, the solution of polyurethane modified with pigment affinity groups is mainly selected, such as Dispers 673 from Digo and BYK-161 from BYK Chemical.

[0044] In some embodiments, the desiccant is selected from at least one of vinyl trimethoxy silane, vinyl triethoxy silane and p-toluenesulfonyl isocyanate.

[0045] In a second aspect, a method for preparing the polyurethane glass primer as described above is provided, comprising the following steps:

[0046] Add silane-modified polyurethane prepolymer, adhesion promoter, carbon black, dispersant, fast-drying solvent, slow-drying solvent, surface-drying catalyst and water remover into a grinder, grind at a rotation speed of 1200-1800 rpm (for example, 1300 rpm, 1400 rpm, 1500 rpm, 1600 rpm) for 3-10 h (for example, 4 h, 5 h, 6 h, 8 h) to obtain the polyurethane glass primer.

[0047] In the present invention, the polyurethane glass primer can be used for bonding between automobile sunroof glass and polyurethane edging material. The operation or process of using the polyurethane glass primer with polyurethane glass sealant or edging material can be a conventional choice in the art and will not be described here.

[0048] In the present invention, the polymerization catalyst used in the silane-modified polyurethane prepolymer is selected as a metal catalyst, mainly for the purpose of efficiently catalyzing the reaction of isocyanate and polyol, because its stability is better and the stability of this type of catalyst in the system is guaranteed; at the same time, a surface-drying catalyst that stably coexists with NCO and urethane bonds and does not cause group self-polymerization reaction is selected to efficiently catalyze and promote the reaction of isocyanate groups with water, which not only makes the primer have good storage stability, but also ensures the film-forming effect of fast surface drying and long storage time. In addition, the present invention also creatively uses low-boiling point environmentally friendly solvents. The combination of slow-drying solvents (organic solvents with relatively high boiling points) and fast-drying solvents (solvents with relatively low boiling points) can achieve the beneficial effects of reducing the surface drying time of the primer and improving the processability, and the solvent is low-toxic / non-toxic and volatile.

[0049] The polyurethane primer of the present invention can be applied to the technical field of polyurethane hemming adhesive. In the synthesis process of the primer, a polymerization catalyst with better stability is used, a low-boiling point environmentally friendly solvent is selected and compounded with a quick-drying solvent, a surface drying catalyst that can stably coexist with NCO groups is matched, and a dewatering agent is added, which greatly shortens the surface drying time of the primer and prolongs its storage time, can better adapt to the production conditions of automobile sunroofs, and has environmental protection advantages; at the same time, it can also ensure that the polyurethane material and the sunroof glass have a higher bonding strength (the peeling strength is better than the existing similar products). DETAILED DESCRIPTION

[0050] In order to understand the technical features and content of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. For those who do not specify specific conditions in the embodiments, they are carried out according to normal conditions or the conditions recommended by the manufacturer.

[0051] In the following examples and comparative examples, the “parts” are all parts by weight.

[0052] In the following examples and comparative examples, the sources of the main raw materials are as follows:

[0053] Neopentyl glycol, commercially available;

[0054] DL-400, a polyether polyol with functionality 2 and molecular weight 400, was purchased from Dongda;

[0055] PCL-2044, polycaprolactone polyol with functionality 2 and molecular weight 400, purchased from Polyren;

[0056] HT-300, purchased from Wanhua Chemical;

[0057] HT-400, purchased from Wanhua Chemical;

[0058] HB-200, purchased from Wanhua Chemical;

[0059] Dibutyltin dimercaptoacetate, purchased from Momentive;

[0060] Dioctyltin mercaptan, purchased from Momentive;

[0061] Bismuth octanoate was purchased from Momentive;

[0062] γ-Mercaptopropyltrimethoxysilane, purchased from Evonik;

[0063] Bis[3-(trimethoxysilyl)propyl]amine, purchased from Evonik; 3-aminopropyltrimethoxysilane, purchased from Evonik;

[0064] γ-Glycidyloxypropyltrimethoxysilane, purchased from Evonik;

[0065] β-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane, purchased from Evonik; trans-monochlorotrifluoropropylene, purchased from Honeywell;

[0066] 1,1,1,3-Tetrafluoropropene, purchased from Honeywell;

[0067] Methylcyclohexane, purchased from Aladdin;

[0068] Ethylene glycol diacetate, purchased from Aladdin;

[0069] Dimorpholine triethyl ether, purchased from Aladdin;

[0070] Bis(dimethylamino)ethyl ether, purchased from Aladdin;

[0071] Bismorpholinyl diethyl ether, purchased from Aladdin;

[0072] Triethylenediamine, purchased from Evonik;

[0073] U carbon, purchased from Orilon;

[0074] 49L carbon black, purchased from Orion;

[0075] Dispersant Dispers 673, purchased from Digo Company;

[0076] Dispersant BYK-161, purchased from BYK Additives;

[0077] Tosyl isocyanate, purchased from Evonik;

[0078] Vinyltrimethoxysilane, purchased from Aladdin;

[0079] Vinyltriethoxysilane was purchased from Aladdin.

[0080] Example 1

[0081] Preparation method of polyurethane glass primer:

[0082] (1) Preparation of silane-modified polyurethane prepolymer

[0083] 10 parts of neopentyl glycol and 100 parts of HT-300 were fully mixed, reacted at 40°C for 60 minutes, then 0.05 parts of dibutyltin dimercaptoacetate were added, and the reaction was continued at 80°C for 9 hours; when the NCO content in the test system was 9-11wt%, 20 parts of γ-mercaptopropyltrimethoxysilane were added to the system, and the reaction was continued at 80°C for 3 hours, and the reaction was stopped when the NCO content in the test system was 4-6wt%, thus obtaining a silane-modified polyurethane prepolymer;

[0084] (2) Preparation of primer

[0085] Weigh 28 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 40 parts of trans-monochlorotrifluoropropylene, 20 parts of butanone, 50 parts of methylcyclohexane, 0.05 parts of dimorpholine triethyl ether, and 1 part of p-toluenesulfonyl isocyanate into a grinder, and grind at a speed of 1500 rpm for 6 hours to obtain a primer.

[0086] Example 2

[0087] Preparation method of polyurethane glass primer:

[0088] (1) Preparation of silane-modified polyurethane prepolymer

[0089] 40 parts of DL-400 (a polyol with a functionality of 2 and a molecular weight of 400) and 100 parts of HT-400 were fully mixed, reacted at 60°C for 60 minutes, then 0.05 parts of dioctyltin mercaptan were added, and the reaction was continued at 80°C for 12 hours; when the NCO content in the test system was 8-10wt%, 20 parts of bis[3-(trimethoxysilyl)propyl]amine were added to the system, and the reaction was continued at 100°C for 4 hours. When the NCO content in the test system was 6-8wt%, the reaction was stopped to obtain a silane-modified polyurethane prepolymer;

[0090] (2) Preparation of primer

[0091] Weigh 35 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 5 parts of γ-glycidyloxypropyltrimethoxysilane, 3 parts of U carbon, 1 part of dispersant BYK-161, 90 parts of trans-monochlorotrifluoropropylene, 20 parts of ethylene glycol diacetate, 0.1 parts of bis(dimethylaminoethyl)ether, and 1 part of vinyltrimethoxysilane, add them into a grinder, and grind at a speed of 1500 rpm for 3 hours to obtain a primer.

[0092] Example 3

[0093] Preparation method of polyurethane glass primer:

[0094] (1) Preparation of silane-modified polyurethane prepolymer

[0095] 30 parts of PCL-2044 (polycaprolactone polyol with functionality 2 and molecular weight 400) and 100 parts of HB-200 were fully mixed, reacted at 60°C for 60 minutes, then 0.03 parts of bismuth octanoate were added, and the reaction was continued at 80°C for 12 hours; the NCO content in the test system was 12-14wt%, 30 parts of 3-aminopropyltrimethoxysilane were added to the system, and the reaction was continued at 80°C for 3 hours, and the reaction was stopped when the NCO content in the test system was 5-7wt%, thus obtaining a silane-modified polyurethane prepolymer;

[0096] (2) Preparation of primer

[0097] Weigh 30 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 5 parts of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 6 parts of 49L carbon black, 1 part of dispersant Dispers 673, 80 parts of 1,1,1,3-tetrafluoropropylene, 30 parts of methylcyclohexane, 0.05 parts of bismorpholinyl diethyl ether, and 1 part of vinyltriethoxysilane into a grinder, and grind at a speed of 1500 rpm for 5 hours to obtain a primer.

[0098] Example 4

[0099] The preparation method of the polyurethane glass primer is similar to that of Example 2, except that the mass ratio of the slow-drying solvent to the fast-drying solvent is 1:8.

[0100] Comparative Example 1

[0101] Preparation method of polyurethane glass primer:

[0102] (1) Preparation of silane-modified polyurethane prepolymer

[0103] 40 parts of DL-400 (a polyol with a functionality of 2 and a molecular weight of 400) and 100 parts of HT-400 were fully mixed, reacted at 60°C for 60 minutes, then 0.05 parts of dioctyltin mercaptan were added, and the reaction was continued at 80°C for 12 hours; when the NCO content in the test system was 8-10wt%, 20 parts of bis[3-(trimethoxysilyl)propyl]amine were added to the system, and the reaction was continued at 100°C for 4 hours. When the NCO content in the test system was 6-8wt%, the reaction was stopped to obtain a silane-modified polyurethane prepolymer;

[0104] (2) Preparation of primer

[0105] Weigh 35 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 5 parts of γ-glycidyloxypropyltrimethoxysilane, 3 parts of U carbon, 1 part of dispersant BYK-161, 80 parts of ethyl acetate and 30 parts of isobutyl ketone, 0.05 parts of triethylenediamine (amine catalyst), and 1 part of vinyltrimethoxysilane into a grinder, and grind at a speed of 1500 rpm for 5 hours to obtain a primer.

[0106] Comparative Example 2

[0107] Preparation method of polyurethane glass primer:

[0108] (1) Preparation of silane-modified polyurethane prepolymer:

[0109] 10 parts of neopentyl glycol and 100 parts of HT-300 were fully mixed, reacted at 40°C for 60 minutes, then 0.05 parts of dibutyltin dimercaptoacetate were added, and the reaction was continued at 80°C for 9 hours; when the NCO content in the test system was 9-11wt%, 20 parts of γ-mercaptopropyltrimethoxysilane were added to the system, and the reaction was continued at 80°C for 3 hours, and the reaction was stopped when the NCO content in the test system was 4-6wt%, thus obtaining a silane-modified polyurethane prepolymer;

[0110] (2) Preparation of primer

[0111] Weigh 28 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 10 parts of trans-monochlorotrifluoropropylene, 10 parts of butanone, 90 parts of methylcyclohexane, 0.05 parts of dimorpholine triethyl ether, and 1 part of p-toluenesulfonyl isocyanate into a grinder, and grind at a speed of 1500 rpm for 6 hours to obtain a primer.

[0112] Comparative Example 3

[0113] Preparation method of polyurethane glass primer:

[0114] (1) Preparation of silane-modified polyurethane prepolymer

[0115] 10 parts of neopentyl glycol and 100 parts of HT-300 were fully mixed, reacted at 40°C for 60 minutes, then 0.05 parts of dibutyltin dimercaptoacetate were added, and the reaction was continued at 80°C for 9 hours; when the NCO content in the test system was 9-11wt%, 20 parts of γ-mercaptopropyltrimethoxysilane were added to the system, and the reaction was continued at 80°C for 3 hours, and the reaction was stopped when the NCO content in the test system was 4-6wt%, thus obtaining a silane-modified polyurethane prepolymer;

[0116] (2) Preparation of primer

[0117] Weigh 28 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 40 parts of trans-monochlorotrifluoropropylene, 20 parts of butanone, 50 parts of methylcyclohexane, 0.05 parts of dibutyltin dimercaptoacetate, and 1 part of p-toluenesulfonyl isocyanate, add them into a grinder, and grind at a speed of 1500 rpm for 6 hours to obtain a primer.

[0118] Comparative Example 4

[0119] Preparation method of polyurethane glass primer:

[0120] (1) Preparation of silane-modified polyurethane prepolymer

[0121] 10 parts of neopentyl glycol and 100 parts of HT-300 were fully mixed, reacted at 40°C for 60 minutes, then 0.05 parts of triethylenediamine were added, and the reaction was continued at 80°C for 9 hours; when the NCO content in the test system was 9-11wt%, 20 parts of γ-mercaptopropyltrimethoxysilane were added to the system, and the reaction was continued at 80°C for 3 hours, and the reaction was stopped when the NCO content in the test system was 4-6wt%, thus obtaining a silane-modified polyurethane prepolymer;

[0122] (2) Preparation of primer

[0123] Weigh 28 parts of the silane-modified polyurethane prepolymer prepared in the above steps, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 40 parts of trans-monochlorotrifluoropropylene, 20 parts of butanone, 50 parts of methylcyclohexane, 0.05 parts of triethylenediamine, and 1 part of p-toluenesulfonyl isocyanate into a grinder, and grind at a speed of 1500 rpm for 6 hours to obtain a primer.

[0124] Adhesion test: The polyurethane primers prepared in each embodiment and comparative example were subjected to adhesion test. The test method is to apply each polyurethane primer on the surface of the glass substrate, and after the primer is dry, glue is applied on the glass substrate coated with the primer, and then placed in an environment of (23±2)℃, (50±5)%RH for 24 hours, and then a 90° peel strength test is performed; the test results are shown in Table 1.

[0125] The viscosity test, solid content test and surface drying time test are conventional test methods in this field and will not be described in detail here.

[0126] Table 1 Physical indexes and performance indexes of the primers obtained in various embodiments and comparative examples

[0127]

[0128]

[0129] Note: When the material after gluing is subjected to peel strength test, the PU material is damaged, which represents the strength of the material itself. The larger the value, the better the bonding effect.

[0130] Experimental summary:

[0131] In each embodiment, during the preparation process of the polyurethane glass primer, the types of polymerization catalysts and surface drying catalysts used are distinguished, and a fast-drying solvent and a slow-drying solvent are combined and a suitable ratio is selected, so that a primer product with low solid content, good storage stability (the NCO content and viscosity do not change much after storage for a period of time), short surface drying time (1-3 minutes) and high bonding strength with PU can be obtained.

[0132] Compared with Example 2, Comparative Example 1 uses a catalyst system and a solvent that are not within the scope of the application, and the storage stability of the obtained primer product is poor, which is manifested in that the NCO content decreases, the viscosity increases, and the surface drying time is longer after storage for a period of time;

[0133] Compared with Example 1, although Comparative Example 2 uses the catalyst type within the protection scope of the present application, the storage stability of the obtained primer product is good, but due to the unreasonable ratio of the added fast-drying solvent and the slow-drying solvent, the surface drying time of the obtained primer product is long; in Comparative Example 3, the polymerization catalyst used in the preparation of the prepolymer and the surface drying catalyst in the primer preparation step are both tin-based, and the polymerization and surface drying catalysts are not differentiated in use, and the storage stability of the obtained primer product is poor; in Comparative Example 4, the polymerization catalyst used in the preparation of the prepolymer and the surface drying catalyst in the primer preparation step are both amine catalysts, and the polymerization catalyst and the surface drying catalyst are not differentiated in use, and the storage stability of the obtained primer product is also poor.

[0134] At the same time, this patented technical solution also has the characteristics of low toxicity / non-toxicity and high volatility due to the use of low-boiling point environmentally friendly solvents.

[0135] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the spirit of the present invention.

Claims

1. A polyurethane glass primer, characterized in that: The components are comprised in the following parts by weight: Silane modified polyurethane prepolymer, 20-40 parts, Adhesion promoter, 1-5 parts, Carbon black, 1-10 parts, Dispersant, 1-2 parts, Quick drying solvent, 50-150 parts, Slow drying solvent, 10-50 parts, Surface-dried catalyst, 0.05-0.5 parts; Dewatering agent, 1-2 parts; The silane-modified polyurethane prepolymer is a polyurethane prepolymer obtained by polymerizing polyol and polyisocyanate in the presence of a polymerization catalyst and then end-capping the prepolymer with a silane coupling agent.

2. The polyurethane glass primer according to claim 1, characterized in that: The preparation method of the silane-modified polyurethane prepolymer comprises the following steps: 5-100 parts by weight of polyol and 50-150 parts by weight of polyisocyanate are mixed, reacted at 40-60° C. for 10-60 minutes, then 0.01-0.05 parts by weight of polymerization catalyst are added, and the reaction is continued at 60-110° C. for 6-12 hours; when the NCO content in the test system is 6-15wt%, 5-30 parts by weight of silane coupling agent are added to the system, and the reaction is carried out at 60-110° C. for 2-5 hours, and the reaction is stopped when the NCO content in the test system is 4-10wt%, thereby obtaining the silane-modified polyurethane prepolymer; Preferably, in the method for preparing the silane-modified polyurethane prepolymer, the polyol is selected from at least one of dipropylene glycol, diethylene glycol, neopentyl glycol, 1,5-pentanediol, and a polyether polyol or polyester polyol having a functionality of 2 and a molecular weight of 200-2000; Preferably, in the method for preparing the silane-modified polyurethane prepolymer, the polyisocyanate is an isocyanate polymer, more preferably at least one selected from hexamethylene diisocyanate polymer, isophorone diisocyanate biuret, isophorone diisocyanate polymer, hydrogenated phenylmethane diisocyanate polymer or hydrogenated phenylmethane diisocyanate biuret, and more preferably hexamethylene diisocyanate polymer; Preferably, in the method for preparing the silane-modified polyurethane prepolymer, the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane and bis[3-(trimethoxysilyl)propyl]amine.

3. The polyurethane glass primer according to claim 2, characterized in that: In the preparation method of the silane-modified polyurethane prepolymer, the polymerization catalyst is selected from at least one of di(dodecylthio)dibutyltin, dialkyltin dimaleate, dialkyltin dithiolate, alkylthiodibutyltin, dibutyltin dimercaptoacetate, dioctyltin dimercaptoacetate, dioctyltin mercaptan, bismuth octanoate, bismuth isooctanoate and bismuth carboxylate.

4. The polyurethane glass primer according to claim 1, characterized in that: The surface-dried catalyst is selected from at least one of N-(dimethylaminoethyl)morpholine, dimorpholine triethyl ether, N-ethylmorpholine, bismorpholinyl diethyl ether and bisdimethylaminoethyl ether, preferably dimorpholine triethyl ether or bismorpholinyl diethyl ether.

5. The polyurethane glass primer according to claim 3 or 4, characterized in that: The polymerization catalyst and the surface-drying catalyst are selected in different types.

6. The polyurethane glass primer according to claim 1, characterized in that: The quick-drying solvent is an environmentally friendly hydrofluoroolefin, or a composite mixture of an environmentally friendly hydrofluoroolefin and a ketone organic solvent; Preferably, the ketone organic solvent is selected from acetone, butanone, isobutyl ketone, and cyclohexanone; Preferably, the environmentally friendly hydrofluoroolefin is selected from one or more of trans-monochlorotrifluoropropene, pentafluoropropane, 1,1,1,3-tetrafluoropropene and cis-1-chloro-3,3,3-trifluoropropene; Preferably, the quick-drying solvent is a mixture of at least one of the environmentally friendly hydrofluoroolefins and acetone or butanone.

7. The polyurethane glass primer according to claim 1, characterized in that: The slow-drying solvent is selected from at least one of methylcyclohexane and ethylene glycol diacetate, preferably methylcyclohexane.

8. The polyurethane glass primer according to claim 1, characterized in that: The mass ratio of the slow-drying solvent to the fast-drying solvent is 1:1 to 1:

9.

9. The polyurethane glass primer according to any one of claims 1 to 8, characterized in that: The adhesion promoter is a silane coupling agent containing an epoxy group in the molecular structure, preferably at least one selected from γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane; The carbon black is selected from at least one of U carbon of Orilon, 49L of Orilon and XPB-756 of Orilon; The dispersant is at least one of polyurethane coating dispersants; The dewatering agent is selected from at least one of vinyl trimethoxy silane, vinyl triethoxy silane and p-toluenesulfonyl isocyanate.

10. The method for preparing the polyurethane glass primer according to any one of claims 1 to 9, characterized in that: The following steps are involved: The silane-modified polyurethane prepolymer, adhesion promoter, carbon black, dispersant, quick-drying solvent, slow-drying solvent, surface-drying catalyst and water remover are added into a grinder and grind at a speed of 1200-1800 rpm for 3-10 hours to obtain the polyurethane glass primer.

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