A polyurethane glass primer and a method for preparing the same

Abstract

The application belongs to the technical field of primer, and particularly relates to a polyurethane glass primer and a preparation method thereof. The polyurethane glass primer comprises the following components in parts: 20-40 parts of silane modified polyurethane prepolymer, 1-5 parts of adhesion promoter, 1-10 parts of carbon black, 1-2 parts of dispersing agent, 50-150 parts of fast-drying solvent, 10-50 parts of slow-drying solvent, 0.05-0.5 parts of surface drying catalyst, and 1-2 parts of water removing agent. The silane modified polyurethane prepolymer is obtained by end-capping the polyurethane prepolymer obtained by polymerizing polyol and polyisocyanate in the presence of a polymerization catalyst with a silane coupling agent. The primer can ensure that the polyurethane edge covering material has high adhesion strength and peeling strength with the sunroof glass, and the primer also has the advantages of low solid content (<30%), short surface drying time (fast surface drying film formation) and long storage time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of primer, and particularly relates to a polyurethane glass primer for bonding between an automobile sunroof glass and a polyurethane edge covering material and a preparation method thereof. BACKGROUND

[0002] The automobile glass edge covering forming process refers to a process in which polyurethane is coated on the surface of the edge of the glass. Before the edge covering forming, a primer is coated on the surface of the glass substrate in advance, and a resin film is formed on the surface of the substrate after curing, so that the surface of the substrate is modified, thereby significantly improving the adhesion between the edge covering material and the substrate.

[0003] After the primer and the polyurethane sealant or edge covering material are successively applied, in order to measure the peeling strength of the material after the primer is used, a 90° peeling test with the substrate needs to be performed. When the peeling test is performed, the polyurethane sealant breaks, which shows the strength of the polyurethane sealant itself, and the greater the value, the better the bonding effect. However, the polyurethane primer contains active groups NCO and urethane bonds, and the active groups will self-polymerize in the presence of a catalyst added in the system, thereby resulting in poor storage stability of the synthesized primer, limiting the service life, and small-dose packaging also increases the packaging cost.

[0004] For example, patent document CN106752838A discloses a polyurethane sealant primer, which has excellent resistance to wet heat aging; patent document CN102516921A discloses a preparation method, which achieves the preparation of a polyurethane glass primer with an NCO content of 0% through silane modification and end capping, and the prepared primer has a long open time; and patent document CN103113819A discloses a primer for polyurethane sealant, which has a short surface drying and curing time. The primers disclosed in these prior arts cannot satisfy the bonding effect when used for bonding between the polyurethane edge covering material and the sunroof glass. Moreover, the solid content of these primers is generally high (all above 30%), which results in high production cost.

[0005] Patent document CN113402963A discloses a preparation method of a polyurethane glass primer, and the obtained glass primer has good adhesion effect and low solid content; and patent document CN115322670A discloses a preparation method of a polyurethane glass primer, which further contains a nano composite material; the glass primers prepared by the above prior arts have the advantages of low solid content and strong adhesion, but they do not involve the investigation of the storage stability of the primer.

[0006] Therefore, 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

[0007] The present application aims at solving the technical problems existing in the prior art for preparing glass primer, and provides a polyurethane glass primer and a preparation method thereof. The prepared primer can ensure that the polyurethane edge sealing material has high bonding strength and peeling strength with the sunroof glass when used with the polyurethane glass sealant or edge sealing material. The primer has the advantages of low solid content (<30%), short surface drying time (fast surface drying and film forming), long storage time, and mainly uses environmentally friendly solvents, which can better adapt to the production conditions of the sunroof.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

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

[0010] Silane-modified polyurethane prepolymer, 20-40 parts (for example, 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 (for example, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts),

[0012] Carbon black, 1-10 parts (for example, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 8 parts),

[0013] Dispersant, 1-2 parts (for example, 1.2 parts, 1.5 parts, 1.8 parts),

[0014] Fast-drying solvent, 50-150 parts (for example, 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] Surface drying catalyst, 0.05-0.5 parts (for example, 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] Water removal agent, 1-2 parts (for example, 1.2 parts, 1.5 parts, 1.8 parts);

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

[0019] In some embodiments, the amounts of the respective raw materials for 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] 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 present application, a polyurethane glass primer is provided. In some embodiments, the method for preparing the silane-modified polyurethane prepolymer comprises the following steps:

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

[0026] In some embodiments, in the method of 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 a polyester polyol having a functionality of 2 and a molecular weight of 200-2000 (for example, 300, 400, 500, 800, 1000, 1200, 1400, 1500, 1600, 1800).

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

[0028] In the present application, for example, the polyisocyanate can be a combination of hexamethylene diisocyanate prepolymer and hydrogenated phenylmethane diisocyanate prepolymer, or a combination of hexamethylene diisocyanate prepolymer and isophorone diisocyanate prepolymer.

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

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

[0031] In this context, 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, the polymerization catalyst in the method of preparing the silane-modified polyurethane prepolymer is selected from at least one of dilauryl tin dimaleate, dialkyl tin dimaleate, dithiol dialkyl tin (such as dithiol dibutyl tin), alkyl sulfide dibutyl tin, dimercaptoacetic acid dibutyl tin, dimercaptoacetic acid dioctyl tin, thiol dioctyl tin (UL-32), bismuth octyldecylate, bismuth iso-octoate, and bismuth carboxylate.

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

[0034] In some embodiments, the polymerization catalyst and the surface drying catalyst are selected from different categories.

[0035] According to the polyurethane glass primer provided by the present application, in some embodiments, the fast-drying solvent is an environmentally friendly hydrofluoroolefin, or a complex 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 fast-drying solvent is a mixture of at least one of the environmentally friendly hydrofluoroolefin and acetone or butanone.

[0039] According to the polyurethane glass primer provided by the present application, 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] In some embodiments of the polyurethane glass primer provided by the present application, the adhesion promoter is a silane coupling agent containing an epoxy group in the molecular structure, preferably at least one selected from the group consisting of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0042] In some embodiments, the carbon black is at least one selected from the group consisting of U Carbon of Elementis, 49L of Elementis and XPB-756 of Elementis.

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

[0044] In some embodiments, the water removal agent is at least one selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane and p-toluenesulfonylisocyanate.

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

[0046] The silane-modified polyurethane prepolymer, the adhesion promoter, the carbon black, the dispersant, the fast drying solvent, the slow drying solvent, the skin drying catalyst and the water removal agent are added to a grinder and ground at a speed of 1200-1800 revolutions per minute (for example, 1300 revolutions per minute, 1400 revolutions per minute, 1500 revolutions per minute, 1600 revolutions per minute) for 3-10 hours (for example, 4 hours, 5 hours, 6 hours, 8 hours), thereby obtaining the polyurethane glass primer.

[0047] In the present application, the polyurethane glass primer can be applied to the adhesion between the automobile sunroof glass and the polyurethane edge sealing material. The operation or process of using the polyurethane glass primer in combination with the polyurethane glass sealant or the edge sealing material can be a conventional choice in the art, which is not described here in detail.

[0048] In the present application, the polymerization catalyst used in the silane-modified polyurethane prepolymer is selected as a metal catalyst, mainly for efficient catalysis of the reaction of isocyanate with polyol, and better stability to ensure the stability of the catalyst in the system; at the same time, the surface-drying catalyst which stably coexists with NCO and carbamate bond without causing group self-polymerization is selected to efficiently catalyze and promote the reaction of isocyanate group 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 application also creatively uses low-boiling-point environmentally friendly solvents, and the use 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 solvents are low-toxicity / non-toxic and easy to evaporate.

[0049] The polyurethane primer of the present application can be applied to the technical field of polyurethane edge coating glue. In the synthesis process of the primer, a polymerization catalyst with better stability is used, a low-boiling-point environmentally friendly solvent is used in combination with a fast-drying solvent, a surface-drying catalyst which can stably coexist with NCO groups is used in combination, and a water-removing 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 the sunroof of a vehicle, and has environmental advantages; at the same time, it can also ensure that the polyurethane material has a relatively high bonding strength (peeling strength is better than that of existing similar products) with the sunroof glass. DETAILED DESCRIPTION

[0050] In order to enable a detailed understanding of the technical features and content of the present application, the preferred embodiments of the present application will be described in more detail below. Although the preferred embodiments of the present application are described in the examples, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. If no specific conditions are specified in the examples, the conditions are carried out according to the conventional conditions or the conditions recommended by the manufacturer.

[0051] In each of the following examples and comparative examples, the "parts" are all weight parts.

[0052] In each of the following examples and comparative examples, the source information of the main raw materials is as follows:

[0053] Neopentyl glycol, commercially available;

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

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

[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 Maytian;

[0060] Dioctyltin mercaptide, purchased from Maytian;

[0061] Bismuth octyldecanoate, purchased from Maytian;

[0062] Gamma-mercaptopropyltrimethoxysilane, purchased from Win Creation;

[0063] Bis[3-(trimethoxysilyl)propyl]amine, purchased from Win Creation; 3- Aminopropyltrimethoxysilane, purchased from Win Creation;

[0064] Gamma-glycidoxypropyltrimethoxysilane, purchased from Win Creation;

[0065] Beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, purchased from Win Creation; Trans-chlorotrifluoropropene, purchased from Honeywell;

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

[0067] Methylcyclohexane, purchased from Aldrich;

[0068] Ethylene glycol diacetate, purchased from Aldrich;

[0069] Dimorpholinethyl ether, purchased from Aldrich;

[0070] Bisdimethylaminoethylether, purchased from Aldrich;

[0071] Bismorpholinodiethylether, purchased from Aldrich;

[0072] Triethylenediamine, purchased from Win Creation;

[0073] U-carbon, purchased from Oligon;

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

[0075] Dispersant Dispers 673, purchased from DeGussa;

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

[0077] Toluenesulfonylisocyanate, purchased from Win Creation;

[0078] Vinyltrimethoxysilane, purchased from Aldrich;

[0079] Vinyltriethoxysilane, purchased from Aldrich.

[0080] Example 1

[0081] Preparation method of polyurethane glass primer

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

[0083] Mix 10 parts of neopentyl glycol and 100 parts of HT-300 thoroughly, react at 40°C for 60 min, then add 0.05 parts of dibutyl tin dimercaptoacetate, continue to react at 80°C for 9 h; when the NCO content in the test system is 9-11 wt%, add 20 parts of γ-mercaptopropyl trimethoxysilane to the system, and continue to react at 80°C for 3 h; when the NCO content in the test system is 4-6 wt%, stop the reaction, and silane modified polyurethane prepolymer is obtained;

[0084] (2) Preparation of primer

[0085] Weigh 28 parts of the silane modified polyurethane prepolymer prepared in the above step, 3 parts of γ-glycidyl ether oxypropyl trimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 40 parts of trans-chlorotrifluoropropene, 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, grind at a speed of 1500 r / min for 6 h, and a primer is obtained.

[0086] Example 2

[0087] Preparation method of polyurethane glass primer

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

[0089] Mix 40 parts of DL-400 (polyol with a functionality of 2 and a molecular weight of 400) and 100 parts of HT-400 thoroughly, react at 60°C for 60 min, then add 0.05 parts of thiol dioctyl tin, continue to react at 80°C for 12 h; when the NCO content in the test system is 8-10 wt%, add 20 parts of bis[3-(trimethoxysilyl)propyl]amine to the system, and continue to react at 100°C for 4 h; when the NCO content in the test system is 6-8 wt%, stop the reaction, and silane modified polyurethane prepolymer is obtained;

[0090] (2) Preparation of primer

[0091] Take 35 parts of the silane-modified polyurethane prepolymer prepared in the above step, 5 parts of γ-glycidoxypropyltrimethoxysilane, 3 parts of U carbon, 1 part of dispersant BYK-161, 90 parts of trans-chlorotrifluoropropene, 20 parts of ethylene glycol diacetate, 0.1 part of bisdimethylaminoethyl ether, 1 part of vinyltrimethoxysilane into a grinder, and grind at a speed of 1500 rpm for 3 h to obtain the primer.

[0092] Example 3

[0093] Preparation method of polyurethane glass primer:

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

[0095] Mix 30 parts of PCL-2044 (poly-caprolactone polyol with functionality 2 and molecular weight 400) and 100 parts of HB-200 thoroughly, and react at 60°C for 60 min. Then add 0.03 parts of bismuth octyldecylate, and continue to react at 80°C for 12 h. The NCO content in the system is 12-14 wt%. Add 30 parts of 3-aminopropyltrimethoxysilane to the system, and continue to react at 80°C for 3 h. Stop the reaction when the NCO content in the system is 5-7 wt% to obtain the silane-modified polyurethane prepolymer.

[0096] (2) Preparation of primer

[0097] Take 30 parts of the silane-modified polyurethane prepolymer prepared in the above step, 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-tetrafluoropropene, 30 parts of methylcyclohexane, 0.05 parts of bis-morpholinyl diethyl ether, and 1 part of vinyltriethoxysilane into a grinder, and grind at a speed of 1500 rpm for 5 h to obtain the primer.

[0098] Example 4

[0099] The preparation method of the polyurethane glass primer is the same as in 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] Mix 40 parts of DL-400 (polyol with functionality of 2 and molecular weight of 400), 100 parts of HT-400 thoroughly, react at 60°C for 60 min, then add 0.05 parts of dithiol dibutyl tin, continue to react at 80°C for 12 h; when the NCO content in the test system is 8-10 wt%, add 20 parts of bis[3-(trimethoxysilyl)propyl]amine to the system, and continue to react at 100°C for 4 h; stop the reaction when the NCO content in the test system is 6-8 wt%, to obtain a silane-modified polyurethane prepolymer;

[0104] (2) Preparation of the primer

[0105] Weigh 35 parts of the silane-modified polyurethane prepolymer prepared in the above step, 5 parts of γ-glycidyloxypropyltrimethoxysilane, 3 parts of U carbon, 1 part of dispersant BYK-161, 80 parts of ethyl acetate, 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 h to obtain the primer.

[0106] Comparative Example 2

[0107] Preparation method of the polyurethane glass primer:

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

[0109] Mix 10 parts of neopentyl glycol, 100 parts of HT-300 thoroughly, react at 40°C for 60 min, then add 0.05 parts of dibutyl tin dimercaptoacetate, continue to react at 80°C for 9 h; when the NCO content in the test system is 9-11 wt%, add 20 parts of γ-mercaptopropyltrimethoxysilane to the system, and continue to react at 80°C for 3 h; stop the reaction when the NCO content in the test system is 4-6 wt%, to obtain a silane-modified polyurethane prepolymer;

[0110] (2) Preparation of the primer

[0111] Weigh 28 parts of the silane-modified polyurethane prepolymer prepared in the above step, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 10 parts of trans-chlorotrifluoropropene, 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 h to obtain the primer.

[0112] Comparative Example 3

[0113] Preparation method of the polyurethane glass primer:

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

[0115] 10 parts of neopentyl glycol, 100 parts of HT-300 were mixed thoroughly, reacted at 40°C for 60 min, then 0.05 parts of dibutyl tin dimercaptoacetate was added, and the reaction was continued at 80°C for 9 h; when the NCO content in the test system was 9-11 wt%, 20 parts of γ-mercaptopropyl trimethoxysilane was added to the system, and the reaction was continued at 80°C for 3 h; when the NCO content in the test system was 4-6 wt%, the reaction was stopped, and a silane-modified polyurethane prepolymer was obtained.

[0116] (2) Preparation of the primer

[0117] 28 parts of the silane-modified polyurethane prepolymer prepared in the above step, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 40 parts of trans-chlorotrifluoropropene, 20 parts of butanone, 50 parts of methylcyclohexane, 0.05 parts of dibutyl tin dimercaptoacetate, and 1 part of p-toluenesulfonyl isocyanate were weighed into a grinder, and ground at a speed of 1500 r / min for 6 h to obtain a primer.

[0118] Comparative Example 4

[0119] Preparation method of the polyurethane glass primer:

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

[0121] 10 parts of neopentyl glycol, 100 parts of HT-300 were mixed thoroughly, reacted at 40°C for 60 min, then 0.05 parts of dibutyl tin dimercaptoacetate was added, and the reaction was continued at 80°C for 9 h; when the NCO content in the test system was 9-11 wt%, 20 parts of γ-mercaptopropyl trimethoxysilane was added to the system, and the reaction was continued at 80°C for 3 h; when the NCO content in the test system was 4-6 wt%, the reaction was stopped, and a silane-modified polyurethane prepolymer was obtained.

[0122] (2) Preparation of the primer

[0123] 28 parts of the silane-modified polyurethane prepolymer prepared in the above step, 3 parts of γ-glycidyloxypropyltrimethoxysilane, 8 parts of U carbon, 1 part of dispersant BYK-161, 40 parts of trans-chlorotrifluoropropene, 20 parts of butanone, 50 parts of methylcyclohexane, 0.05 parts of dibutyl tin dimercaptoacetate, and 1 part of p-toluenesulfonyl isocyanate were weighed into a grinder, and ground at a speed of 1500 r / min for 6 h to obtain a primer.

[0124] Adhesion test: the polyurethane primer prepared in each example and comparative example was subjected to adhesion test. The test method was to coat the polyurethane primer on the surface of a glass substrate, and after the primer was tack-free, glue was applied on the glass substrate coated with the primer, and then the glued material was placed at (23±2) °C, (50±5) % RH for 24 h, and then subjected to 90° peeling strength test; the test results are shown in Table 1.

[0125] As to the viscosity test, solid content test and tack-free time test, they are all conventional test methods in the art, which will not be repeated here.

[0126] Table 1: physical and performance indicators of the primer prepared in each example and comparative example

[0127]

[0128]

[0129] Note: when the glued material is subjected to peeling strength test, the PU material is broken, which represents the strength of the material itself, and the larger the value is, the better the adhesion effect is.

[0130] Experimental summary:

[0131] In the preparation of polyurethane glass primer paint, the types of polymerization catalyst and tack-free catalyst used in each example are distinguished, and the combination of fast-drying solvent and slow-drying solvent and the selection of appropriate ratio can obtain a primer product with low solid content, good storage stability (little change in NCO content and viscosity after storage for a period of time), short tack-free time (1-3 min) and high adhesion strength with PU.

[0132] Compared with Example 2, the storage stability of the primer product obtained by using the catalyst system and solvent outside the scope of protection in Comparative Example 1 is poor, which is manifested by the decrease in NCO content, the increase in viscosity and the long tack-free time after storage for a period of time;

[0133] Compared with Example 1, although the catalyst type used in Comparative Example 2 is within the scope of protection, the storage stability of the primer product obtained is good, but because the ratio of fast-drying solvent to slow-drying solvent is unreasonable, the tack-free time of the obtained primer product is long; the polymerization catalyst used in the preparation of prepolymer and the tack-free catalyst in the preparation steps of the primer paint in Comparative Example 3 are both tin-based, and the polymerization and tack-free catalysts are not used separately, so the storage stability of the obtained primer product is poor; the polymerization catalyst used in the preparation of prepolymer and the tack-free catalyst in the preparation steps of the primer paint in Comparative Example 4 are both amine catalysts, and the polymerization catalyst and the tack-free catalyst are not used separately, so the storage stability of the obtained primer product is also poor.

[0134] Meanwhile, the patent technical scheme has the characteristics of low toxicity / non-toxicity and easy volatilization due to the use of low-boiling environmentally friendly solvents.

[0135] The above has described the embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the spirit of the present application.

Claims

1. A polyurethane glass primer, characterized in that, The components comprise, by weight, the following parts: Silane-modified polyurethane prepolymer, 20-40 parts. Adhesion accelerator, 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; Dehydrating agent, 1-2 parts; The silane-modified polyurethane prepolymer is a polyurethane prepolymer obtained by polymerizing a polyol and a polyisocyanate in the presence of a polymerization catalyst and then end-capping the prepolymer with a silane coupling agent. The surface-drying catalyst is selected from at least one of N-(dimethylaminoethyl)morpholine, dimorpholine triethyl ether, N-ethylmorpholine, bismorpholine diethyl ether, and bisdimethylaminoethyl ether; The polymerization catalyst and the surface drying catalyst are selected from different types; The polymerization catalyst is selected from at least one of dialkyltin dimaleate, dialkyltin dithiol, dibutyltin alkylthioate, dibutyltin dithioacetate, dioctyltin dithioacetate, dioctyltin thiol, and bismuth carboxylate. The fast-drying solvent is an environmentally friendly hydrofluoroolefin, or a mixture of an environmentally friendly hydrofluoroolefin and a ketone organic solvent; 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. The slow-drying solvent is selected from at least one of methylcyclohexane and ethylene glycol diacetate.

2. The polyurethane glass primer according to claim 1, characterized in that, The preparation method of the silane-modified polyurethane prepolymer includes the following steps: Mix 5-100 parts by weight of polyol with 50-150 parts by weight of polyisocyanate and react at 40-60℃ for 10-60 min. Then add 0.01-0.05 parts by weight of polymerization catalyst and continue the reaction at 60-110℃ for 6-12 h. When the NCO content in the test system is 6-15 wt%, add 5-30 parts by weight of silane coupling agent to the system and react at 60-110℃ for 2-5 h. Stop the reaction when the NCO content in the test system is 4-10 wt%, and the silane-modified polyurethane prepolymer is obtained.

3. The polyurethane glass primer according to claim 2, characterized in that, 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 polyether polyols or polyester polyols with a functionality of 2 and a molecular weight of 200-2000.

4. The polyurethane glass primer according to claim 2, characterized in that, In the method for preparing the silane-modified polyurethane prepolymer, the polyisocyanate is an isocyanate polymer selected from at least one of hexamethylene diisocyanate polymer, isophorone diisocyanate biuret, isophorone diisocyanate polymer, hydrogenated phenylmethane diisocyanate polymer, or hydrogenated phenylmethane diisocyanate biuret.

5. The polyurethane glass primer according to claim 4, characterized in that, The polyisocyanate is a hexamethylene diisocyanate polymer.

6. The polyurethane glass primer according to claim 2, characterized in that, 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.

7. The polyurethane glass primer according to claim 1, characterized in that, The alkylthiodibutyltin is di(dodecylthio)dibutyltin; The bismuth carboxylate is bismuth caprylate or bismuth isooctanoate.

8. The polyurethane glass primer according to claim 1, characterized in that, The surface-drying catalyst is selected from dimorpholine triethyl ether or bismorpholine diethyl ether.

9. The polyurethane glass primer according to claim 1, characterized in that, The ketone organic solvents are selected from acetone, butanone, isobutanone, and cyclohexanone.

10. The polyurethane glass primer according to claim 1, characterized in that, The fast-drying solvent is a mixture of at least one of environmentally friendly hydrofluoroolefins and acetone or butanone.

11. The polyurethane glass primer according to claim 1, characterized in that, The slow-drying solvent is methylcyclohexane.

12. 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.

13. The polyurethane glass primer according to any one of claims 1-12, characterized in that, The adhesion promoter is a silane coupling agent containing epoxy groups in its molecular structure; The carbon black is selected from at least one of Orion's U Carbon, Orion's 49L and Orion's XPB-756. The dispersant is at least one of polyurethane coating dispersants; The dehydrating agent is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, and p-toluenesulfonyl isocyanate.

14. The polyurethane glass primer according to claim 13, characterized in that, The adhesion promoter is selected from at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

15. The method for preparing the polyurethane glass primer according to any one of claims 1-14, characterized in that, Includes the following steps: The silane-modified polyurethane prepolymer, adhesion promoter, carbon black, dispersant, fast-drying solvent, slow-drying solvent, surface-drying catalyst, and dehydrating agent are added to a grinding mill and ground at a speed of 1200-1800 rpm for 3-10 hours to obtain the polyurethane glass primer.

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