Bi-component polyurethane sealant applicable to bonding of automobile headlamp structure and preparation method of bi-component polyurethane sealant

Abstract

The invention provides a two-component polyurethane sealant suitable for bonding an automobile headlamp structure and a preparation method of the two-component polyurethane sealant, and relates to the technical field of polyurethane sealants. The double-component polyurethane sealant comprises a component A and a component B, wherein the mixing mass ratio of the component A to the component B is 1: 1-1: 5; the component A is prepared from the following raw materials in parts by weight: 80 to 120 parts of isocyanate group terminated organic silicon modified polyurethane prepolymer, 15 to 40 parts of powder filler and 0.5 to 2 parts of auxiliaries; the component B is prepared from the following raw materials in parts by weight: 100 to 160 parts of polyol, 50 to 200 parts of powder filler, 0.01 to 0.1 part of catalyst and 0.1 to 20 parts of auxiliary agent. According to the invention, the polyurethane sealant prepared from the single-ended dihydroxyalkyl polydimethylsiloxane composite polyol for the first time has better water resistance, and has better bonding force, cold and hot impact resistance, ultraviolet aging resistance, elongation at break and anti-seismic property on a low-surface-energy material (PP).

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane sealants, and in particular to a two-component polyurethane sealant suitable for bonding automobile headlight structures and a preparation method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, the production and sales volume of automobiles in my country has increased year by year, and more stringent requirements have been put forward for the quality and performance of various automobile parts. As an important part of ensuring driving safety, automobile lights have multiple functions such as lighting and signal indication. The lights are mainly composed of three parts: lampshade, bulb and sealant. Among them, the sealant should not only have excellent bonding properties, but also show outstanding air tightness, shock resistance, water resistance and anti-aging properties. These characteristics are crucial to improving the overall performance and service life of the lights.

[0003] At present, the common sealants for automobile headlights are mainly divided into two categories: room temperature glue and hot melt glue. Room temperature glue mainly includes single-component and two-component silicone sealants, which are resistant to high temperatures and have good stability. However, due to the high volatile matter contained in them, long-term use will damage the anti-fog coating of the headlights, seriously affecting the normal use of the headlights, limiting their application. Hot melt adhesives are divided into two categories: thermoplastic and reactive. Thermoplastic hot melt adhesives are generally not resistant to high temperatures and have low bonding strength. With the upgrading of the headlight manufacturing industry, this type of sealant has been gradually eliminated; reactive hot melt adhesives require moisture curing, so their initial strength is not high, resulting in a narrow range of applications.

[0004] Two-component polyurethane sealant has the advantages of fast curing speed, deep curing at room temperature, good elasticity and high bonding strength. If its resistance to high temperature aging, UV aging and hot and cold shock can be improved, it will be expected to become the next generation of sealant for bonding headlight structures. Summary of the invention

[0005] The invention provides a two-component polyurethane sealant suitable for bonding automobile headlight structures and a preparation method thereof, the purpose of which is to solve the above-mentioned problems existing in the background technology.

[0006] In order to achieve the above purpose, the embodiment of the present invention provides a two-component polyurethane sealant suitable for bonding automobile headlight structures and a preparation method thereof, the two-component polyurethane sealant has the advantages of good bonding performance, good elasticity, resistance to cold and hot shocks, high temperature resistance, resistance to ultraviolet light aging and low volatility, etc. It does not damage the anti-fog coating of the headlight structure, which is of great significance in promoting the development of the automobile industry.

[0007] The embodiment of the present invention provides a two-component polyurethane sealant suitable for bonding automobile headlight structures, in which a flexible silicone segment is introduced into the side chain of polyurethane, and the elongation at break of the modified polyurethane sealant is increased by about 90%, and the shear strength (PC-PC) attenuation rate of double 85 aging and ultraviolet aging is reduced to less than 5%. These outstanding performance advantages are conducive to ensuring the stable and long-term operation of automobile headlights. The sealant includes component A and component B, and the mixing mass ratio of component A to component B is 1:5;

[0008] Component A contains the following raw materials in parts by mass:

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

[0010] 0.5-2 parts of additives;

[0011] In parts by mass, component B contains the following raw materials:

[0012]

[0013] Preferably, the isocyanate group-terminated silicone-modified polyurethane prepolymer in component A is prepared by reacting a difunctional isocyanate, a difunctional polyol and a single-terminal dihydroxyalkyl polydimethylsiloxane, and has a viscosity of 100 to 10,000 mPa.s at 25° C.; and an isocyanate group content of 2% to 20%.

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

[0015]

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

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

[0018] Preferably, the powder filler in the component A 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 accounts for 15% to 40% of the polyurethane prepolymer.

[0019] Preferably, the auxiliary agent in the A component is at least one of a thixotropic agent, an antioxidant, a water scavenger, 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 scavenger is one or more of molecular sieves, calcium oxide, and p-toluenesulfonyl isocyanate; the latent curing agent is one or more of oxazolidines, ketimines, and aldimines; and the total amount of the auxiliary agents added accounts for 0.5% to 2% of the polyurethane prepolymer.

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

[0021] Preferably, 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 accounts for 50% to 200% of the polyol.

[0022] Preferably, 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 isooctanoate; the tertiary amine catalyst is triethylene diamine or triethanolamine; and the added amount of the catalyst is 0.01% to 0.1% of the total mass of the polyol.

[0023] Preferably, the auxiliary agent in the B component is at least one of a thixotropic agent, an antioxidant, an ultraviolet light stabilizer or a dewatering 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-methoxybenzophenone; the dewatering agent is one or more of molecular sieves, calcium oxide and p-toluenesulfonyl isocyanate; the total amount of the auxiliary agents added accounts for 0.1% to 20% of the polyol.

[0024] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned two-component polyurethane sealant for bonding automobile headlight structures, comprising the following steps:

[0025] S1: Take 1 equivalent molecular weight of 500 to 3000 hydroxyl-terminated liquid polybutadiene HTPB and 0.5 equivalent molecular weight of 1000 to 4000 single-terminated dihydroxyl polydimethylsiloxane PDMS, heat and dehydrate under vacuum at 105° C. for 1 to 2 hours, cool to below 40° C., add 4 equivalents of difunctional isocyanate, and react under nitrogen atmosphere at 60 to 80° C. with stirring until the isocyanate group content is stable, to prepare an isocyanate-terminated silicone-modified polyurethane prepolymer;

[0026] Wherein, the difunctional isocyanate is selected from diphenylmethane diisocyanate MDI, toluene diisocyanate TDI or polydiphenylmethane diisocyanate; it can 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), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI);

[0027] The above reaction equation is as follows:

[0028]

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

[0030] S2: 80 to 120 parts of the isocyanate group-terminated silicone-modified polyurethane prepolymer, 15 to 40 parts of heavy calcium carbonate and white carbon black are added to a planetary mill, and vacuum stirred at room temperature for 1 to 2 hours to prepare component A;

[0031] S3: Weigh 40-80 parts of hydroxy-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 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 into a planetary machine, stir under vacuum at 100-110° C. for at least 2 hours and then cool to room temperature to prepare component B;

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

[0033] The above scheme of the present invention has the following beneficial effects:

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

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

[0036] (3) The two-component polyurethane sealant prepared by the present invention has better resistance to cold and heat shock and UV aging. DETAILED DESCRIPTION

[0037] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, they are described in detail below in conjunction with specific embodiments.

[0038] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

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

[0040] In view of the existing problems, the present invention provides a two-component polyurethane sealant suitable for bonding automobile 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 contains the following raw materials in parts by mass:

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

[0043] 0.5-2 parts of additives;

[0044] In parts by mass, component B contains the following raw materials:

[0045]

[0046] Preferably, the isocyanate group-terminated silicone-modified polyurethane prepolymer in component A is prepared by reacting a difunctional isocyanate, a difunctional polyol and a single-terminal dihydroxyalkyl polydimethylsiloxane, and has a viscosity of 100 to 10,000 mPa.s at 25° C.; and an isocyanate group content of 2% to 20%.

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

[0048]

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

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

[0051] Preferably, the powder filler in the component A 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 accounts for 15% to 40% of the polyurethane prepolymer.

[0052] Preferably, the auxiliary agent in the A component is at least one of a thixotropic agent, an antioxidant, a water scavenger, 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 scavenger is one or more of molecular sieves, calcium oxide, and p-toluenesulfonyl isocyanate; the latent curing agent is one or more of oxazolidines, ketimines, and aldimines; and the total amount of the auxiliary agents added accounts for 0.5% to 2% of the polyurethane prepolymer.

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

[0054] Preferably, 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 accounts for 50% to 200% of the polyol.

[0055] Preferably, 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 isooctanoate; the tertiary amine catalyst is triethylene diamine or triethanolamine; and the added amount of the catalyst is 0.01% to 0.1% of the total mass of the polyol.

[0056] Preferably, the auxiliary agent in the B component is at least one of a thixotropic agent, an antioxidant, an ultraviolet light stabilizer or a dewatering 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-methoxybenzophenone; the dewatering agent is one or more of molecular sieves, calcium oxide and p-toluenesulfonyl isocyanate; the total amount of the auxiliary agents added accounts for 0.1% to 20% of the polyol.

[0057] Based on a general concept of the invention, an embodiment of the present invention provides a method for preparing the above-mentioned two-component polyurethane sealant for bonding automobile headlight structures, comprising the following steps:

[0058] S1: Take 1 equivalent molecular weight of 500 to 3000 hydroxyl-terminated liquid polybutadiene HTPB and 0.5 equivalent molecular weight of 1000 to 4000 single-terminated dihydroxyl polydimethylsiloxane PDMS, heat and dehydrate under vacuum at 100 to 120° C. for 1 to 2 hours, cool to below 40° C., add 4 equivalents of difunctional isocyanate, and react under nitrogen atmosphere at 60 to 80° C. with stirring until the isocyanate group (NCO) content is stable, to prepare an NCO-terminated silicone-modified polyurethane prepolymer;

[0059] Wherein, the difunctional isocyanate is selected from diphenylmethane diisocyanate MDI, toluene diisocyanate TDI or polydiphenylmethane diisocyanate; it can 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), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI);

[0060] The above reaction equation is as follows:

[0061]

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

[0063] S2: 80 to 120 parts of the isocyanate group-terminated silicone-modified polyurethane prepolymer, 15 to 40 parts of heavy calcium carbonate and white carbon black are added to a planetary mill, and vacuum stirred at room temperature for 1 to 2 hours to prepare component A;

[0064] S3: Weigh 40-80 parts of hydroxy-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 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 into a planetary machine, stir under vacuum at 100-110° C. for at least 2 hours and then cool to room temperature to prepare component B;

[0065] S4: Mix the component A and the 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 of a polyurethane prepolymer 1, comprising the following steps:

[0069] First, 50 parts of hydroxyl-terminated liquid polybutadiene and 50 parts of single-terminated dihydroxyalkyl polydimethylsiloxane were added to a three-necked flask, heated in an oil bath at 105° C. for vacuum dehydration for 2 hours, and cooled to less than 40° C. Then, 120 parts of diisocyanate were added, the temperature was raised to 80° C., and the reaction was stirred in vacuum for more than 2 hours to obtain an NCO-terminated polyurethane prepolymer 1 with an NCO content of 14-16%.

[0070] The hydroxyl-terminated liquid polybutadiene is preferably Ricon 130 hydroxyl-terminated polybutadiene polyol produced by Rayville Hydrocarbon Chemicals; the single-terminated dihydroxyalkyl polydimethylsiloxane is preferably Shin-Etsu Chemical X-22-2500 methyl silicone oil; and the diisocyanate is preferably WANNATE MDI 50 produced by Wanhua Chemical.

[0071] Example 2

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

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

[0074] The hydroxyl-terminated liquid polybutadiene is preferably Ricon 130 hydroxyl-terminated polybutadiene polyol produced by Raymond Chemicals; and the diisocyanate is preferably WANNATE MDI 50 produced by Wanhua Chemicals.

[0075] Example 3

[0076] This embodiment provides a preparation process of a polyurethane prepolymer 3, comprising 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, heated in an oil bath at 105° C. for vacuum dehydration for 2 hours, and cooled to less than 40° C. Then, 120 parts of diisocyanate were added, the temperature was raised to 80° C., and the reaction was stirred in vacuum for more than 2 hours to obtain NCO-terminated polyurethane prepolymer 3 with an NCO content of 14-16%.

[0078] The hydroxyl-terminated liquid polybutadiene is preferably Ricon 130 hydroxyl-terminated polybutadiene polyol produced by Rayville Hydrocarbon Chemicals; the diisocyanate is preferably WANNATE MDI 50 produced by Wanhua Chemical; and the hydroxyl-terminated polydimethylsiloxane is KF-3200 methyl silicone oil produced by Shin-Etsu Chemical.

[0079] Example 4

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

[0081] The method of 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 white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0083] Step 2, component B: weigh 60 parts of Ricon 130 type hydroxyl-terminated polybutadiene polyol from Cray Valley Hydrocarbon Chemicals, 40 parts of N-56 type polyester polyol from Huada Chemical, 120 parts of heavy calcium carbonate, 40 parts of light calcium carbonate, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieves, 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 machine, stir in vacuum at 100°C for 2 hours and then cool to room temperature.

[0084] Step 3: Mix the component A and the component B in 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 automobile headlight structures.

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

[0088] Step 1, component A: Weigh 100 parts of the polyurethane prepolymer 1 of Example 1, 40 parts of heavy calcium carbonate and 1 part of white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0089] Step 2, component B: weigh 80 parts of Ricon 130 type hydroxyl-terminated polybutadiene polyol from Cray Valley Hydrocarbon Chemicals, 20 parts of N-56 type polyester polyol from Huada Chemical, 120 parts of heavy calcium carbonate, 40 parts of light calcium carbonate, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieves, 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 machine, stir in vacuum at 100°C for 2 hours and then cool to room temperature.

[0090] Step 3: Mix the component A and the component B in 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 automobile headlight structures.

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

[0094] Step 1, component A: Weigh 100 parts of the polyurethane prepolymer 1 of Example 1, 40 parts of heavy calcium carbonate and 1 part of white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0095] Step 2, component B: weigh 80 parts of Ricon 130 type hydroxyl-terminated polybutadiene polyol from Cray Valley Hydrocarbon Chemicals, 20 parts of N-56 type polyester polyol from Huada Chemical, 160 parts of heavy calcium carbonate, 3 parts of white carbon black, 0.8 parts of 1,4-butanediol, 2 parts of molecular sieves, 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 machine, stir in vacuum at 100°C for 2 hours and then cool to room temperature.

[0096] Step 3: Mix the component A and the component B in 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 automobile headlight structures.

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

[0100] Step 1, component A: Weigh 100 parts of the polyurethane prepolymer 1 of Example 1, 40 parts of heavy calcium carbonate and 1 part of white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0101] Step 2, component B: 100 parts of Ricon 130 type hydroxy-terminated polybutadiene polyol from Cray Valley Hydrocarbon 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 sieves, 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 were weighed into a planetary machine, and the mixture was stirred in vacuum at 100° C. for 2 hours and then cooled to room temperature.

[0102] Step 3: Mix the component A and the component B in 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 comprises 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 white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0106] Step 2, component B: weigh 80 parts of Ricon 130 type hydroxyl-terminated polybutadiene polyol from Cray Valley Hydrocarbon Chemicals, 20 parts of N-56 type polyester polyol from Huada Chemical, 120 parts of heavy calcium carbonate, 3 parts of white carbon black, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieves, 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 machine, stir in vacuum at 100°C for 2 hours and then cool to room temperature.

[0107] Step 3: Mix the component A and the component B in 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 comprises 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 white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0111] Step 2, component B: 80 parts of Ricon 130 type hydroxy-terminated polybutadiene polyol from Cray Valley Hydrocarbon Chemicals, 20 parts of single-terminated dihydroxyalkyl polydimethylsiloxane from Shin-Etsu Chemical X-22-2500 type, 120 parts of heavy calcium carbonate, 3 parts of white carbon black, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieves, 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 were weighed into a planetary machine, and the mixture was stirred at 100° C. under vacuum for 2 hours and then cooled to room temperature.

[0112] Step 3: Mix the component A and the component B in 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 comprises 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 white carbon black into a planetary mill, and stir under vacuum at 25° C. for 2 hours.

[0116] Step 2, component B: weigh 80 parts of Ricon 130 type hydroxyl-terminated polybutadiene polyol from Cray Valley Hydrocarbon Chemicals, 20 parts of N-56 type polyester polyol from Huada Chemical, 120 parts of heavy calcium carbonate, 3 parts of white carbon black, 0.8 parts of 1,4-butanediol, 2 parts of 3A molecular sieves, 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 machine, stir in vacuum at 100°C for 2 hours and then cool to room temperature.

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

[0118] The polyurethane adhesives prepared in the above 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: 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 with Comparative Example 1, it can be found that the introduction of silicone can greatly 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 by blending will result in poor compatibility between polyurethane and silicone, which will lead to reduced performance of the sealant.

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

[0125] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A two-component polyurethane sealant suitable for bonding automobile headlight structures, characterized in that: The invention comprises a component A and a component B, wherein the mixing mass ratio of the component A to the component B is 1:1 to 1:5; Component A contains the following raw materials in parts by mass: 80-120 parts of isocyanate-terminated silicone-modified polyurethane prepolymer, 15-40 parts of powder filler, 0.5-2 parts of additives; In parts by mass, component B contains the following raw materials:

2. The two-component polyurethane sealant for bonding automobile headlight structures according to claim 1, characterized in that: The isocyanate-terminated silicone-modified polyurethane prepolymer in component A is prepared by reacting difunctional isocyanate, difunctional polyol and single-terminal dihydroxyl polydimethylsiloxane, and has 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 for bonding automobile headlight structures according to claim 2, characterized in that: The structural formula of the single-terminated bis-hydroxyalkyl polydimethylsiloxane is shown in Formula I below: In formula I, m is an integer of 1-20, and R is selected from C 1-8 Alkyl, ether and ester groups.

4. The two-component polyurethane sealant for bonding automobile headlight structures 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 accounts for 15% to 40% of the polyurethane prepolymer.

5. The two-component polyurethane sealant for bonding automobile headlight structures according to claim 1, characterized in that: The auxiliary agent in the component A is at least one of a thixotropic agent, an antioxidant, a water-removing 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-removing agent is one or more of molecular sieves, calcium oxide and p-toluenesulfonyl isocyanate; the latent curing agent is one or more of oxazolidines, ketimines and aldimines; and the total addition amount of the auxiliary agents accounts for 0.5% to 2% of the polyurethane prepolymer.

6. The two-component polyurethane sealant for bonding automobile headlight structures according to claim 1, characterized in that: The polyol in the B component is at least one of polyether polyol, polyester polyol, plant polyol and hydroxyl-terminated polybutadiene polyol.

7. The two-component polyurethane sealant for bonding automobile headlight structures 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 accounts for 50% to 200% of the polyol.

8. The two-component polyurethane sealant for bonding automobile headlight structures 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 isooctanoate; the tertiary amine catalyst is triethylene diamine or triethanolamine; and the added amount of the catalyst is 0.01% to 0.1% of the total mass of the polyol.

9. The two-component polyurethane sealant for bonding automobile headlight structures 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 dewatering 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-methoxybenzoyl propionone; the dewatering agent is one or more of molecular sieves, calcium oxide and p-toluenesulfonyl isocyanate; and the total addition amount of the auxiliary agents accounts for 0.1% to 20% of the polyol.

10. The method for preparing a two-component polyurethane sealant for bonding automobile headlight structures according to any one of claims 1 to 9, characterized in that: The steps include: S1: Take 1 equivalent molecular weight of 500 to 3000 hydroxyl-terminated liquid polybutadiene and 0.5 equivalent molecular weight of 1000 to 4000 single-terminated dihydroxyl polydimethylsiloxane, heat and dehydrate under vacuum at 100 to 120° C. for 1 to 2 hours, cool to below 40° C., add 4 equivalents of difunctional isocyanate, and react under nitrogen atmosphere at 60 to 80° C. with stirring until the isocyanate group content is stable, to prepare an isocyanate-terminated silicone-modified polyurethane prepolymer; S2: 80 to 120 parts of the isocyanate group-terminated silicone-modified polyurethane prepolymer, 15 to 40 parts of heavy calcium carbonate and white carbon black are added to a planetary mill, and vacuum stirred at room temperature for 1 to 2 hours to prepare component A; S3: Weigh 40-80 parts of hydroxy-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 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 into a planetary machine, stir under vacuum at 100-110° C. for at least 2 hours and then cool to room temperature to prepare component B; S4: Mix the component A and the component B in a mass ratio of 1:1 to 1:5 to obtain a two-component polyurethane sealant.

Images