Two-component polyurethane sealant for bonding automobile headlamp structure and preparation method thereof

Abstract

The application provides a two-component polyurethane sealant suitable for automobile headlight structure bonding and a preparation method thereof, and relates to the technical field of polyurethane sealants. The two-component polyurethane sealant comprises component A and component B, and the mixing mass ratio of the component A and the component B is 1:1 to 1:5. The component A comprises the following raw materials: isocyanate group terminated organic silicon modified polyurethane prepolymer 80-120 parts, powder filler 15-40 parts, and auxiliary agent 0.5-2 parts. The component B comprises the following raw materials: polyol 100-160 parts, powder filler 50-200 parts, catalyst 0.01-0.1 parts, and auxiliary agent 0.1-20 parts. The polyurethane sealant prepared by using single-end double-hydroxyl alkyl polydimethylsiloxane composite polyol for the first time has better water resistance, better bonding force on low surface energy material (PP), better cold and hot impact resistance, better ultraviolet aging resistance, better elongation at break, and better shock resistance.

Description

Technical Field

[0001] This invention relates to the field of polyurethane sealant technology, and in particular to a two-component polyurethane sealant suitable for bonding automotive headlight structures and its preparation method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, my country's automobile production and sales have been increasing year by year, placing more stringent requirements on the quality and performance of various automotive components. As a crucial component for ensuring driving safety, automotive lights perform multiple functions, including illumination and signal indication. Automotive lights mainly consist of three parts: the lamp cover, the bulb, and the sealant. The sealant, in particular, must not only possess excellent adhesive properties but also exhibit outstanding airtightness, shock resistance, water resistance, and aging resistance. These characteristics are essential for improving the overall performance and lifespan of automotive lights.

[0003] Currently, common automotive headlight sealants mainly fall into two categories: room temperature (RTL) adhesives and hot melt adhesives. RTL adhesives primarily include single-component and two-component silicone sealants, which are heat-resistant and stable. However, due to their high volatile content, long-term use can damage the anti-fog coating of the headlights, severely affecting their normal operation and limiting their application. Hot melt adhesives are divided into thermoplastic and reactive types. Thermoplastic hot melt adhesives are generally not heat-resistant and have low bond strength; with the upgrading of the automotive headlight manufacturing industry, this type of sealant has been gradually phased out. Reactive hot melt adhesives require moisture curing, resulting in low initial strength and limiting their application range.

[0004] Two-component polyurethane sealant has advantages such as fast curing speed, deep curing at room temperature, good elasticity and high bonding strength. If its resistance to high temperature aging, ultraviolet aging and thermal shock can be improved, it is expected to become the next generation of sealant for automotive lighting structure bonding. Summary of the Invention

[0005] This invention provides a two-component polyurethane sealant suitable for bonding automotive headlight structures and its preparation method, with the aim of solving the aforementioned problems existing in the background art.

[0006] To achieve the above objectives, embodiments of the present invention provide a two-component polyurethane sealant suitable for bonding automotive headlight structures and its preparation method. This two-component polyurethane sealant possesses advantages such as good adhesion, good elasticity, resistance to thermal shock, high temperature resistance, UV aging resistance, and low volatile matter content. Furthermore, it does not damage the anti-fog coating of the headlight structure, which is of great significance to the development of the automotive industry.

[0007] This invention provides a two-component polyurethane sealant suitable for bonding automotive headlight structures. Flexible silicone segments are introduced into the side chains of the polyurethane, resulting in a 90% increase in elongation at break and a reduction in the shear strength (PC-PC) decay rate under 85°C aging and UV aging to less than 5%. These significant performance advantages contribute to ensuring the stable and long-term operation of automotive headlights. The sealant comprises component A and component B, with a mixing mass ratio of 1:5.

[0008] Component A comprises the following raw materials by weight:

[0009] 80-120 parts of isocyanate-terminated silicone-modified polyurethane prepolymer 15-40 parts of powder filler

[0010] Additives: 0.5–2 parts;

[0011] Component B comprises the following raw materials in parts by weight:

[0012]

[0013] Preferably, the isocyanate-terminated organosilicon-modified polyurethane prepolymer in component A is prepared by reacting a difunctional isocyanate, a difunctional polyol, and a monohydroxyl-terminated polydimethylsiloxane, with a viscosity of 100–10000 mPa·s at 25°C and an isocyanate group content of 2%–20%.

[0014] Preferably, the structural formula of the single-terminated dihydroxyalkyl polydimethylsiloxane is shown in Formula I below:

[0015]

[0016] In Equation I, m is an integer from 1 to 20, and R is selected from C. 1-8 Alkyl, ether, and ester groups.

[0017] More preferably, m is an integer from 2 to 15, and R is selected from -CH2-, -CH2CH2-, -CH2CH2OCH2CH2-, and -CH2CH2CH2COOCH2CH2CH2CH2-.

[0018] Preferably, the powder filler in component A is at least one of nano-montmorillonite, nano-silica, heavy calcium carbonate, light calcium carbonate, and nano-titanium dioxide, and the total amount added accounts for 15% to 40% of the polyurethane prepolymer.

[0019] Preferably, the additives in component A are at least one of thixotropic agents, antioxidants, dehydrating agents, and latent curing agents; the thixotropic agent is one or more of carbon black, silica, and light nano-calcium carbonate; the antioxidant is one or more of 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, and dialkyldiphenylamine; the dehydrating agent is one or more of molecular sieves, calcium oxide, and p-toluenesulfonyl isocyanate; the latent curing agent is one or more of oxazolidines, ketimins, and aldehyde imins; and the total amount of additives added accounts for 0.5% to 2% of the polyurethane prepolymer.

[0020] Preferably, the polyol in component B is at least one of polyether polyol, polyester polyol, plant-based polyol, and hydroxyl-terminated polybutadiene polyol.

[0021] Preferably, the powder filler in component B is at least one of nano-montmorillonite, nano-silica, heavy calcium carbonate, light calcium carbonate, and nano-titanium dioxide, and the total amount added accounts for 50% to 200% of the polyol.

[0022] Preferably, the catalyst in component B is an organotin catalyst, an organobismuth catalyst, or a tertiary amine catalyst; the organotin catalyst is stannous octoate or dibutyltin dilaurate; the organobismuth catalyst is bismuth neodecanoate or bismuth isooctanoate; the tertiary amine catalyst is triethylenediamine or triethanolamine; and the amount of catalyst added is 0.01% to 0.1% of the total mass of the polyol.

[0023] Preferably, the additives in component B are at least one of a thixotropic agent, an antioxidant, a UV stabilizer, or a dehydrating agent; the thixotropic agent is one or more of carbon black, silica, and light nano-calcium carbonate; the antioxidant is one or more of 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, and dialkyldiphenylamine; the UV stabilizer is one or more of phenyl benzoate, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxyphenylacetone; the dehydrating agent is one or more of molecular sieve, calcium oxide, and p-toluenesulfonyl isocyanate; and the total amount of additives is 0.1% to 20% of the polyol.

[0024] Based on a general inventive concept, embodiments of the present invention provide a method for preparing the above-mentioned two-component polyurethane sealant suitable for bonding automotive headlight structures, comprising the following steps:

[0025] S1: Take 1 equivalent of hydroxyl-terminated liquid polybutadiene (HTPB) with a molecular weight of 500 to 3000 and 0.5 equivalents of mono-dihydroxyalkyl polydimethylsiloxane (PDMS) with a molecular weight of 1000 to 4000. Dehydrate under vacuum heating at 105°C for 1 to 2 hours. After cooling to below 40°C, add 4 equivalents of difunctional isocyanate. Stir the reaction under a nitrogen atmosphere at 60 to 80°C until the isocyanate group content is stable to prepare an isocyanate-terminated organosilicon-modified polyurethane prepolymer.

[0026] The difunctional isocyanate is selected from diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), or polydiphenylmethane diisocyanate; it may also be selected from at least one of 2,4-toluene diisocyanate (2,4-TDI) and / or 2,6-toluene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI) and / or 2,4'-diphenylmethane diisocyanate (2,4'-MDI), xylenebenzene diisocyanate (XDI), hexamethylene diisocyanate (HDI), and isoflurone diisocyanate (IPDI).

[0027] The above reaction equation is as follows:

[0028]

[0029] More preferably, the hydroxyl-terminated liquid polybutadiene has a molecular weight of 2000-3000 and a hydroxyl value of 40-52 mgKOH / g; the mono-terminated dihydroxyalkyl polydimethylsiloxane has a molecular weight of 1000-3000 and a hydroxyl value of 36-48 mgKOH / g.

[0030] S2: Take 80-120 parts of the isocyanate-terminated organosilicon-modified polyurethane prepolymer, 15-40 parts of heavy calcium carbonate and fumed silica into a planetary mixer, and stir under vacuum at room temperature for 1-2 hours to prepare component A.

[0031] S3: Weigh 40-80 parts of hydroxyl-terminated polybutadiene polyol, 30-50 parts of polyester polyol, 100-160 parts of heavy calcium carbonate, 20-60 parts of light calcium carbonate, 0.6-1.0 parts of 1,4-butanediol, 1-3 parts of molecular sieve, 0.1-0.5 parts of 2,6-di-tert-butyl-4-methylphenol, 0.1-0.5 parts of 2,4-dihydroxybenzophenone, and 0.01-0.1 parts of dibutyltin dilaurate into a planetary mixer, stir under vacuum at 100-110℃ for at least 2 hours, and then cool to room temperature to prepare component B;

[0032] S4: Mix component A and component B in a mass ratio of 1:1 to 1:5 to obtain a two-component polyurethane sealant.

[0033] The above-described solution of the present invention has the following beneficial effects:

[0034] (1) The polyurethane sealant prepared by the present invention using single-ended dihydroxyalkyl polydimethylsiloxane has better water resistance and higher adhesion to low surface energy materials (PP).

[0035] (2) Compared with traditional polyurethane prepolymers, the polyurethane prepolymer prepared by the present invention using polyols and single-terminal dihydroxyalkyl polydimethylsiloxane gives the sealant higher elongation at break and better seismic performance.

[0036] (3) The two-component polyurethane sealant prepared by the present invention has better resistance to thermal shock and UV aging. Detailed Implementation

[0037] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments.

[0038] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0039] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0040] To address the existing problems, this invention provides a two-component polyurethane sealant suitable for bonding automotive headlight structures, comprising component A and component B, wherein the mixing mass ratio of component A to component B is 1:5.

[0041] Component A comprises the following raw materials by weight:

[0042] 80-120 parts of isocyanate-terminated silicone-modified polyurethane prepolymer 15-40 parts of powder filler

[0043] Additives: 0.5–2 parts;

[0044] Component B comprises the following raw materials in parts by weight:

[0045]

[0046] Preferably, the isocyanate-terminated organosilicon-modified polyurethane prepolymer in component A is prepared by reacting a difunctional isocyanate, a difunctional polyol, and a monohydroxyl-terminated polydimethylsiloxane, with a viscosity of 100–10000 mPa·s at 25°C and an isocyanate group content of 2%–20%.

[0047] Preferably, the structural formula of the single-terminated dihydroxyalkyl polydimethylsiloxane is shown in Formula I below:

[0048]

[0049] In Equation I, m is an integer from 1 to 20, and R is selected from C. 1-8 Alkyl, ether, and ester groups.

[0050] More preferably, m is an integer from 2 to 15, and R is selected from -CH2-, -CH2CH2-, -CH2CH2OCH2CH2-, and -CH2CH2CH2COOCH2CH2CH2CH2-.

[0051] Preferably, the powder filler in component A is at least one of nano-montmorillonite, nano-silica, heavy calcium carbonate, light calcium carbonate, and nano-titanium dioxide, and the total amount added accounts for 15% to 40% of the polyurethane prepolymer.

[0052] Preferably, the additives in component A are at least one of thixotropic agents, antioxidants, dehydrating agents, and latent curing agents; the thixotropic agent is one or more of carbon black, silica, and light nano-calcium carbonate; the antioxidant is one or more of 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, and dialkyldiphenylamine; the dehydrating agent is one or more of molecular sieves, calcium oxide, and p-toluenesulfonyl isocyanate; the latent curing agent is one or more of oxazolidines, ketimins, and aldehyde imins; and the total amount of additives added accounts for 0.5% to 2% of the polyurethane prepolymer.

[0053] Preferably, the polyol in component B is at least one of polyether polyol, polyester polyol, plant-based polyol, and hydroxyl-terminated polybutadiene polyol.

[0054] Preferably, the powder filler in component B is at least one of nano-montmorillonite, nano-silica, heavy calcium carbonate, light calcium carbonate, and nano-titanium dioxide, and the total amount added accounts for 50% to 200% of the polyol.

[0055] Preferably, the catalyst in component B is an organotin catalyst, an organobismuth catalyst, or a tertiary amine catalyst; the organotin catalyst is stannous octoate or dibutyltin dilaurate; the organobismuth catalyst is bismuth neodecanoate or bismuth isooctanoate; the tertiary amine catalyst is triethylenediamine or triethanolamine; and the amount of catalyst added is 0.01% to 0.1% of the total mass of the polyol.

[0056] Preferably, the additives in component B are at least one of a thixotropic agent, an antioxidant, a UV stabilizer, or a dehydrating agent; the thixotropic agent is one or more of carbon black, silica, and light nano-calcium carbonate; the antioxidant is one or more of 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, and dialkyldiphenylamine; the UV stabilizer is one or more of phenyl benzoate, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxyphenylacetone; the dehydrating agent is one or more of molecular sieve, calcium oxide, and p-toluenesulfonyl isocyanate; and the total amount of additives is 0.1% to 20% of the polyol.

[0057] Based on a general inventive concept, embodiments of the present invention provide a method for preparing the above-mentioned two-component polyurethane sealant suitable for bonding automotive headlight structures, comprising the following steps:

[0058] S1: Take 1 equivalent of hydroxyl-terminated liquid polybutadiene HTPB with a molecular weight of 500 to 3000 and 0.5 equivalents of mono-dihydroxyalkyl polydimethylsiloxane PDMS with a molecular weight of 1000 to 4000. Dehydrate under vacuum heating at 100 to 120°C for 1 to 2 hours. After cooling to below 40°C, add 4 equivalents of difunctional isocyanate. Stir the reaction under a nitrogen atmosphere at 60 to 80°C until the isocyanate group (NCO) content is stable to prepare an NCO-terminated organosilicon modified polyurethane prepolymer.

[0059] The difunctional isocyanate is selected from diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), or polydiphenylmethane diisocyanate; it may also be selected from at least one of 2,4-toluene diisocyanate (2,4-TDI) and / or 2,6-toluene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI) and / or 2,4'-diphenylmethane diisocyanate (2,4'-MDI), xylenebenzene diisocyanate (XDI), hexamethylene diisocyanate (HDI), and isoflurone diisocyanate (IPDI).

[0060] The above reaction equation is as follows:

[0061]

[0062] More preferably, the hydroxyl-terminated liquid polybutadiene has a molecular weight of 2000-3000 and a hydroxyl value of 40-52 mgKOH / g; the mono-terminated dihydroxyalkyl polydimethylsiloxane has a molecular weight of 1000-3000 and a hydroxyl value of 36-48 mgKOH / g.

[0063] S2: Take 80-120 parts of the isocyanate-terminated organosilicon-modified polyurethane prepolymer, 15-40 parts of heavy calcium carbonate and fumed silica into a planetary mixer, and stir under vacuum at room temperature for 1-2 hours to prepare component A.

[0064] S3: Weigh 40-80 parts of hydroxyl-terminated polybutadiene polyol, 30-50 parts of polyester polyol, 100-160 parts of heavy calcium carbonate, 20-60 parts of light calcium carbonate, 0.6-1.0 parts of 1,4-butanediol, 1-3 parts of molecular sieve, 0.1-0.5 parts of 2,6-di-tert-butyl-4-methylphenol, 0.1-0.5 parts of 2,4-dihydroxybenzophenone, and 0.01-0.1 parts of dibutyltin dilaurate into a planetary mixer, stir under vacuum at 100-110℃ for at least 2 hours, and then cool to room temperature to prepare component B;

[0065] S4: Mix component A and component B in a mass ratio of 1:1 to 1:5 to obtain a two-component polyurethane sealant.

[0066] The following is a detailed description through specific embodiments.

[0067] Example 1

[0068] This embodiment provides a preparation process for polyurethane prepolymer 1, including the following steps:

[0069] First, 50 parts of hydroxyl-terminated liquid polybutadiene and 50 parts of mono-dihydroxyalkyl polydimethylsiloxane were added to a three-necked flask and dehydrated under vacuum at 105°C in an oil bath for 2 hours, then cooled to below 40°C. Next, 120 parts of diisocyanate were added, the temperature was raised to 80°C, and the mixture was stirred under vacuum for at least 2 hours to obtain NCO-terminated polyurethane prepolymer 1 with an NCO content of 14–16%.

[0070] Among them, the hydroxyl-terminated liquid polybutadiene is preferably Ricon 130 polybutadiene polyol from Ricon Carbon Chemicals Co., Ltd.; the mono-dihydroxyalkyl polydimethylsiloxane is preferably Shin-Etsu Chemical X-22-2500 methyl silicone oil; and the diisocyanate is preferably WanNATE MDI 50 from Wanhua Chemical Co., Ltd.

[0071] Example 2

[0072] This embodiment provides a preparation process for polyurethane prepolymer 2, including the following steps:

[0073] First, 100 parts of hydroxyl-terminated liquid polybutadiene were added to a three-necked flask and dehydrated under vacuum at 105°C in an oil bath for 2 hours, then cooled to below 40°C. Next, 120 parts of diisocyanate were added, the temperature was raised to 80°C, and the mixture was stirred under vacuum for more than 2 hours to obtain NCO-terminated polyurethane prepolymer 2 with an NCO content of 14-16%.

[0074] The preferred hydroxyl-terminated liquid polybutadiene is Ricon 130 polybutadiene polyol from Ricon Carbon Chemicals; the preferred diisocyanate is WanNATE MDI 50 from Wanhua Chemical.

[0075] Example 3

[0076] This embodiment provides a preparation process for polyurethane prepolymer 3, including the following steps:

[0077] First, 50 parts of hydroxyl-terminated liquid polybutadiene and 50 parts of hydroxyl-terminated polydimethylsiloxane were added to a three-necked flask and dehydrated under vacuum at 105°C in an oil bath for 2 hours, then cooled to below 40°C. Next, 120 parts of diisocyanate were added, the temperature was raised to 80°C, and the mixture was stirred under vacuum for at least 2 hours to obtain NCO-terminated polyurethane prepolymer 3 with an NCO content of 14–16%.

[0078] The preferred hydroxyl-terminated liquid polybutadiene is Ricon 130 polybutadiene polyol from Ricon Carbon Chemicals Co., Ltd.; the preferred diisocyanate is WanNATE MDI 50 from Wanhua Chemical Co., Ltd.; and the preferred hydroxyl-terminated polydimethylsiloxane is Shin-Etsu Chemical KF-3200 methyl silicone oil.

[0079] Example 4

[0080] This embodiment provides a method for preparing a two-component polyurethane sealant suitable for bonding automotive headlight structures.

[0081] The method in this embodiment specifically includes the following steps:

[0082] Step 1, Component A: Weigh 100 parts of the polyurethane prepolymer 1 prepared in Example 1, 40 parts of heavy calcium carbonate and 1 part of fumed silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0083] Step 2, Component B: Weigh out 60 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 40 parts of N-56 polyester polyol from BGI Chemicals, 120 parts of heavy calcium carbonate, 40 parts of light calcium carbonate, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer, and 0.02 parts of dibutyltin dilaurate catalyst into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0084] Step 3: Mix component A and component B at a mass ratio of 1:5 to obtain the two-component polyurethane sealant.

[0085] Example 5

[0086] This embodiment provides a method for preparing a two-component polyurethane sealant suitable for bonding automotive headlight structures.

[0087] The method in this embodiment specifically includes the following steps:

[0088] Step 1, Component A: Weigh 100 parts of polyurethane prepolymer 1 from Example 1, 40 parts of heavy calcium carbonate and 1 part of silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0089] Step 2, Component B: Weigh 80 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 20 parts of N-56 polyester polyol from Huada Chemicals, 120 parts of heavy calcium carbonate, 40 parts of light calcium carbonate, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, and 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0090] Step 3: Mix component A and component B at a mass ratio of 1:3 to obtain the two-component polyurethane sealant.

[0091] Example 6

[0092] This embodiment provides a method for preparing a two-component polyurethane sealant suitable for bonding automotive headlight structures.

[0093] The method in this embodiment specifically includes the following steps:

[0094] Step 1, Component A: Weigh 100 parts of polyurethane prepolymer 1 from Example 1, 40 parts of heavy calcium carbonate and 1 part of silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0095] Step 2, Component B: Weigh 80 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 20 parts of N-56 polyester polyol from Huada Chemicals, 160 parts of heavy calcium carbonate, 3 parts of silica, 0.8 parts of 1,4-butanediol, 2 parts of molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, and 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0096] Step 3: Mix component A and component B at a mass ratio of 1:1 to obtain the two-component polyurethane sealant.

[0097] Example 7

[0098] This embodiment provides a method for preparing a two-component polyurethane sealant suitable for bonding automotive headlight structures.

[0099] The method in this embodiment specifically includes the following steps:

[0100] Step 1, Component A: Weigh 100 parts of polyurethane prepolymer 1 from Example 1, 40 parts of heavy calcium carbonate and 1 part of silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0101] Step 2, Component B: Weigh 100 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 120 parts of heavy calcium carbonate, 40 parts of light calcium carbonate, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer, and 0.02 parts of dibutyltin dilaurate catalyst into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0102] Step 3: Mix component A and component B at a mass ratio of 1:5 to obtain the two-component polyurethane sealant.

[0103] Comparative Example 1

[0104] A method for preparing a two-component polyurethane adhesive specifically includes the following steps:

[0105] Step 1, Component A: Weigh 100 parts of the polyurethane prepolymer 2 prepared in Example 2, 40 parts of heavy calcium carbonate and 1 part of fumed silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0106] Step 2, Component B: Weigh 80 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 20 parts of N-56 polyester polyol from Huada Chemicals, 120 parts of heavy calcium carbonate, 3 parts of silica, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer, and 0.02 parts of dibutyltin dilaurate catalyst into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0107] Step 3: Mix component A and component B at a mass ratio of 1:5 to obtain a two-component polyurethane adhesive.

[0108] Comparative Example 2

[0109] A method for preparing a two-component polyurethane adhesive specifically includes the following steps:

[0110] Step 1, Component A: Weigh 100 parts of the polyurethane prepolymer 2 prepared in Example 2, 40 parts of heavy calcium carbonate and 1 part of fumed silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0111] Step 2, Component B: Weigh 80 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 20 parts of Shin-Etsu Chemical X-22-2500 mono-dihydroxyalkyl polydimethylsiloxane, 120 parts of heavy calcium carbonate, 3 parts of silica, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer, and 0.02 parts of dibutyltin dilaurate catalyst into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0112] Step 3: Mix component A and component B at a mass ratio of 1:3 to obtain a two-component polyurethane adhesive.

[0113] Comparative Example 3

[0114] A method for preparing a two-component polyurethane adhesive specifically includes the following steps:

[0115] Step 1, Component A: Weigh 100 parts of the polyurethane prepolymer 3 prepared in Example 3, 40 parts of heavy calcium carbonate and 1 part of fumed silica into a planetary mixer and stir under vacuum at 25°C for 2 hours.

[0116] Step 2, Component B: Weigh 80 parts of Ricon 130 hydroxyl-terminated polybutadiene polyol from Clayville Carbon Chemicals, 20 parts of N-56 polyester polyol from Huada Chemicals, 120 parts of heavy calcium carbonate, 3 parts of silica, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieve, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol antioxidant, 0.2 parts of 2,4-dihydroxybenzophenone UV stabilizer, and 0.02 parts of dibutyltin dilaurate catalyst into a planetary mixer, stir under vacuum at 100°C for 2 hours, and then cool to room temperature.

[0117] Step 3: Mix component A and component B at a mass ratio of 1:3 to obtain a two-component polyurethane adhesive.

[0118] The polyurethane adhesives prepared in Examples 4 to 7 and Comparative Examples 1 to 3 were subjected to performance tests according to the following standards, and the test results are shown in Table 1 below: Surface drying time test standard: GB / T 13477, tensile strength and elongation at break test standard: GB / T 528, shear strength test standard: GB / T 7124.

[0119] Table 1

[0120]

[0121]

[0122] By comparing Example 5 and Comparative Example 1, it can be found that the introduction of organosilicon can significantly improve the elongation at break, hydrolysis resistance and UV aging resistance of the sealant.

[0123] By comparing Example 5 and Comparative Example 2, it can be found that simply introducing silicone through blending results in poor compatibility between polyurethane and silicone, which in turn leads to a decrease in the various properties of the sealant.

[0124] By comparing Example 5 and Comparative Example 3, it can be found that the sealant containing hydroxyl-terminated polydimethylsiloxane has a higher elongation at break, but its other properties are not as good as those of the sealant containing single-terminated dihydroxyl hydrocarbon polydimethylsiloxane. Overall, the sealant containing single-terminated dihydroxyl hydrocarbon polydimethylsiloxane has better performance.

[0125] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A two-component polyurethane sealant for bonding of automotive headlamp structures, characterized in that, The A component and the B component are included, and the mixing mass ratio of the A component and the B component is 1:1 to 1:5; The A component includes the following raw materials in mass parts: an isocyanate group terminated silicone modified polyurethane prepolymer 80~120 parts, a powder filler 15~40 parts, an auxiliary agent 0.5~2 parts; The B component includes the following raw materials in mass parts: a polyol 100~160 parts, a powder filler 50~200 parts, a catalyst 0.01~0.1 parts, an auxiliary agent 0.1~20 parts; The isocyanate group terminated silicone modified polyurethane prepolymer in the A component is prepared by reacting a difunctional isocyanate, a difunctional polyol and a mono-terminated bis-hydroxy alkyl polydimethylsiloxane; The mono-terminated bis-hydroxy alkyl polydimethylsiloxane has a structural formula as shown in the following formula I: ； Formula I; In formula I, m is an integer from 1 to 20, R is selected from C 1-8 alkyl, ether, ester groups.

2. The two-component polyurethane sealant for the structural bonding of automotive headlamp according to claim 1, characterized in that, The A component is an isocyanate-terminated organosilicon-modified polyurethane prepolymer having a viscosity of 100 to 10,000 mPa-s at 25°C ; and an isocyanate group content of 2 to 20%.

3. The two-component polyurethane sealant suitable for structural bonding of automotive headlamp according to claim 1, characterized in that, The powder filler in the A component is at least one of nano montmorillonite, nano silicon dioxide, heavy calcium carbonate, light calcium carbonate and nano titanium dioxide, and the total addition amount is 15%~40% of the polyurethane prepolymer.

4. The two-component polyurethane sealant suitable for structural bonding of automotive headlamp according to claim 1, characterized in that, The auxiliary agent in the A component is at least one of a thixotropic agent, an antioxidant, a water removal agent and a latent curing agent; the thixotropic agent is one or more of carbon black, white carbon black and light nano calcium carbonate; the antioxidant is one or more of 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol and dialkyl diphenylamine; the water removal agent is one or more of molecular sieve, calcium oxide and p-methylbenzenesulfonyl isocyanate; the latent curing agent is one or more of oxazolidine, ketimine and aldimine; and the total addition amount of the auxiliary agent is 0.5%~2% of the polyurethane prepolymer.

5. The two-component polyurethane sealant suitable for structural bonding of automotive headlamp according to claim 1, characterized in that, The polyol in the B component is at least one of a polyether polyol, a polyester polyol, a plant polyol and a hydroxyl terminated polybutadiene polyol.

6. The two-component polyurethane sealant suitable for the structural bonding of automotive headlamp according to claim 1, characterized in that, The powder filler in the B component is at least one of nano montmorillonite, nano silicon dioxide, heavy calcium carbonate, light calcium carbonate and nano titanium dioxide, and the total addition amount is 50%~200% of the polyol.

7. The two-component polyurethane sealant suitable for structural bonding of automotive headlamp according to claim 1, characterized in that, The catalyst in the B component is an organic tin catalyst, an organic bismuth catalyst or a tertiary amine catalyst; the organic tin catalyst is stannous octoate or dibutyltin dilaurate; the organic bismuth catalyst is bismuth neodecanoate or bismuth isooctoate; the tertiary amine catalyst is triethylenediamine or triethanolamine; and the addition amount of the catalyst is 0.01%~0.1% of the total mass of the polyol.

8. The two-component polyurethane sealant suitable for structural bonding of automotive headlamp according to claim 1, characterized in that, The auxiliary agent in the B component is at least one of a thixotropic agent, an antioxidant, an ultraviolet light stabilizer or a water removal agent; the thixotropic agent is one or more of carbon black, white carbon black and light nano calcium carbonate; the antioxidant is one or more of 2,6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol and dialkyl diphenylamine; the ultraviolet light stabilizer is one or more of phenyl o-hydroxybenzoate, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxy benzalacetophenone; the water removal agent is one or more of molecular sieve, calcium oxide and p-methylbenzenesulfonyl isocyanate; and the total addition amount of the auxiliary agent is 0.1%~20% of the polyol.

9. The method for preparing two-component polyurethane sealant for the structural bonding of automotive headlamp according to any one of claims 1 to 8, characterized in that, The method includes the following steps: S1: 1 equivalent of hydroxyl-terminated liquid polybutadiene with a molecular weight of 500-3000 and 0.5 equivalent of mono-tailed dihydroxylalkyl polydimethylsiloxane with a molecular weight of 1000-4000 are vacuum-heated and dehydrated at 100-120 ℃ for 1-2 h, and then cooled to below 40 ℃, and 4 equivalents of a difunctional isocyanate is added, and the reaction is stirred at 60-80 ℃ under a nitrogen atmosphere until the isocyanate group content is stable, to obtain an isocyanate group-terminated silicone-modified polyurethane prepolymer; S2: 80-120 parts of the isocyanate group-terminated silicone-modified polyurethane prepolymer, 15-40 parts of heavy calcium carbonate and white carbon black are added to a planetary mixer, and stirred at room temperature under vacuum for 1-2 h, to obtain component A; S3: 40-80 parts of a hydroxyl-terminated polybutadiene polyol, 30-50 parts of a polyester polyol, 100-160 parts of heavy calcium carbonate, 20-60 parts of light calcium carbonate, 0.6-1.0 parts of 1,4-butanediol, 1-3 parts of molecular sieves, 0.1-0.5 parts of 2,6-di-tert-butyl-4-methylphenol, 0.1-0.5 parts of 2,4-dihydroxybenzophenone and 0.01-0.1 parts of dibutyltin dilaurate are weighed into a planetary mixer, and stirred at 100-110 ℃ under vacuum for at least 2 h, and then cooled to room temperature, to obtain component B; S4: the component A and the component B are mixed in a mass ratio of 1:1 to 1:5, to obtain a two-component polyurethane sealant.

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