Ultrahigh-modulus single-component polyurethane windshield glass glue and preparation method thereof

Abstract

The invention provides ultrahigh-modulus single-component polyurethane windshield glass glue and a preparation method thereof, and belongs to the technical field of adhesives. The single-component polyurethane windshield glass glue is prepared from the following components in percentage by mass: 25%-35% of a first polyurethane prepolymer, 10%-20% of a second polyurethane prepolymer, 18%-25% of carbon black, 15%-20% of calcium carbonate, 15%-25% of a first plasticizer, 0.5%-1% of a water absorption stabilizer and 0.3%-0.8% of a first catalyst, the first polyurethane prepolymer is prepared from first polyisocyanate and polyether polyol; the second polyurethane prepolymer includes a second polyisocyanate and a polycarbonate diol. The elongation at break of the single-component polyurethane windshield glass cement reaches 400% or above, the shear strength reaches 6 MPa or above, the tensile strength reaches 10 MPa or above, and the storage modulus is 20 MPa or above.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to an ultra-high modulus single-component polyurethane windshield adhesive and its preparation method. Background Technology

[0002] One-component polyurethane windshield sealant is mainly composed of isocyanate (NCO)-terminated polyurethane prepolymer, fillers, plasticizers, catalysts, etc. Its key characteristic is its ability to react with moisture in the air at room temperature to form a high-strength elastomer. This type of structural adhesive possesses excellent mechanical and physical properties, chemical resistance, water resistance, low-temperature resistance, and vibration and impact resistance. Therefore, it is widely used for bonding automotive front and rear windshields, side windows, sunroofs, and panoramic sunroofs.

[0003] With the development of the new energy vehicle industry, the requirements for the strength and modulus of polyurethane windshield sealants are becoming increasingly stringent. Traditional sealants mainly rely on increasing the crosslinking density of the curing system to improve the final modulus of the product; however, increasing the crosslinking density significantly reduces the product's toughness. To balance the toughness and modulus requirements of polyurethane windshield sealants, the storage modulus of high-modulus polyurethane windshield sealants currently on the market is around 16 MPa, and the elongation at break is around 350%. To meet the higher requirements for strength, toughness, and storage modulus of automotive windshield sealants, a new type of polyurethane windshield sealant needs to be developed. Summary of the Invention

[0004] To address the issues of insufficient energy storage modulus and toughness in existing polyurethane windshield sealants, this invention provides a one-component polyurethane windshield sealant. This one-component polyurethane windshield sealant possesses ultra-high energy storage modulus, excellent toughness, and strength.

[0005] Specifically, in order to achieve the above objectives, the present invention adopts the following technical solution: A single-component polyurethane windshield sealant, by weight percentage, comprises the following components: 25%~35% of a first polyurethane prepolymer, 10%~20% of a second polyurethane prepolymer, 18%~25% of carbon black, 15%~20% of calcium carbonate, 15%~25% of a first plasticizer, 0.5%~1% of a water-absorbing stabilizer, and 0.3%~0.8% of a first catalyst; the first polyurethane prepolymer is prepared from a first polyisocyanate and a polyether polyol as main raw materials, wherein the molar mass of the polyether polyol is 6000 g / mol~7000 g / mol; the second polyurethane prepolymer is prepared from a second polyisocyanate and polycarbonate diol as main raw materials.

[0006] In a preferred embodiment, the carbon black has a DBP oil absorption value ≥ 100 mL / 100 g.

[0007] In a preferred embodiment, the first plasticizer is at least one of phthalate and alkyl sulfonate.

[0008] In a preferred embodiment, the water-absorbing stabilizer is p-toluenesulfonyl isocyanate.

[0009] In a preferred embodiment, the first catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dibutyltin dichloride, and alkylthiodibutyltin Fomrez UL-1.

[0010] In a preferred embodiment, the first polyurethane prepolymer comprises the following components in weight percentage: 9%~20% first polyisocyanate, 60%~80% polyether polyol, 10%~25% second plasticizer, and 0.01%~0.05% second catalyst.

[0011] In a further preferred embodiment, the first polyisocyanate is one or more of diphenylmethylene diisocyanate, methyl 3-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, and isophthalic diisocyanate.

[0012] In a further preferred embodiment, the polyether polyol is a polyether triol with a molar mass of 6000 g / mol to 7000 g / mol.

[0013] In a further preferred embodiment, the second plasticizer is at least one of phthalate, terephthalate, and alkyl sulfonate.

[0014] In a further preferred embodiment, the second catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, 2,2-bismorpholinodiethyl ether, and 1,8-diazacycloundecene.

[0015] In a preferred embodiment, the second polyurethane prepolymer is composed of the following components by mass percentage: 15%~25% second polyisocyanate, 55%~70% polycarbonate diol, 15%~25% third plasticizer, and 0.1%~0.5% third catalyst; the sum of the mass percentages of all components is 100%.

[0016] In a further preferred embodiment, the second polyisocyanate is one or more of diphenylmethylene diisocyanate, methyl 3-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, and isophthalic diisocyanate.

[0017] In a further preferred embodiment, the polycarbonate diol is one or more of the following: polyhexene carbonate diol, poly-1,6-hexanediol carbonate diol, polycaprolactone hexene carbonate diol, polyethylene carbonate diol, polypropylene carbonate diol, polycyclohexanediol-1,6-hexanediol carbonate diol, and poly-1,5-pentanediol-1,6-hexanediol carbonate diol.

[0018] In a further preferred embodiment, the third plasticizer is at least one of phthalate, terephthalate, and alkyl sulfonate.

[0019] In a further preferred embodiment, the third catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, 2,2-bismorpholinodiethyl ether, and 1,8-diazacycloundecene.

[0020] The present invention also provides a method for preparing the single-component polyurethane windshield sealant, comprising the following steps: mixing the first polyurethane prepolymer, the second polyurethane prepolymer, the carbon black, the calcium carbonate, the first plasticizer, the water-absorbing stabilizer and the first catalyst evenly to obtain the single-component polyurethane windshield sealant; maintaining the temperature of the mixture system ≤68℃ during the mixing process.

[0021] The technical solution of the present invention has the following beneficial effects: (1) The single-component polyurethane windshield sealant provided by the present invention has an elongation at break of more than 400%, a shear strength of more than 6 MPa, a tensile strength of more than 10 MPa, and a storage modulus of more than 20 MPa, which can meet the higher requirements of automotive windshield sealant.

[0022] (2) In this invention, by introducing polycarbonate diol into the second polyurethane prepolymer, the strength and modulus of the polyurethane elastomer are greatly improved; at the same time, the toughness of the polyurethane product is balanced by the addition of polyether polyol with a molar mass of 6000~7000g / mol. Detailed Implementation

[0023] The following description, in conjunction with embodiments, clearly and completely describes the technical solutions of this application, so that those skilled in the art can fully understand this application. Obviously, the described embodiments are merely some preferred embodiments of this application, and not all embodiments. Any equivalent modifications or substitutions made by those skilled in the art to the following embodiments without creative effort are within the protection scope of this application.

[0024] Ordinal numbers used in this application, such as "first" and "second," are for descriptive purposes only to distinguish identical or similar objects and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Methods not described in detail in the following embodiments are conventional methods well-known to those skilled in the art.

[0025] A specific embodiment of the present invention provides a single-component polyurethane windshield sealant, comprising the following components by mass percentage: 25%~35% first polyurethane prepolymer, 10%~20% second polyurethane prepolymer, 18%~25% carbon black, 15%~20% calcium carbonate, 15%~25% first plasticizer, 0.5%~1% water-absorbing stabilizer, and 0.3%~0.8% first catalyst; the first polyurethane prepolymer comprises a first polyisocyanate and a polyether polyol, wherein the molar mass of the polyether polyol is 6000 g / mol~7000 g / mol; the second polyurethane prepolymer comprises a second polyisocyanate and polycarbonate diol.

[0026] As an example, the mass percentage of the first polyurethane prepolymer is 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%, and is not limited thereto.

[0027] As an example, the mass percentage of the second polyurethane prepolymer is 10%, 10.5%, 11%, 11.5%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, and is not limited thereto.

[0028] As an example, the carbon black mass percentage is 18%, 18.3%, 18.5%, 18.6%, 18.8%, 19%, 19.5%, 20%, 21%, 22%, 23%, 24% or 25%, and is not limited thereto.

[0029] As an example, the mass percentage of calcium carbonate is 15%, 15.5%, 16%, 18.6%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5% or 20%, and is not limited thereto.

[0030] As an example, the mass percentage of the first plasticizer is 15%, 15.5%, 15.8%, 16%, 16.1%, 16.3%, 16.5%, 16.7%, 16.9%, 17%, 17.2%, 17.3%, 17.4%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 21%, 22%, 23%, 24%, or 25%, and is not limited thereto.

[0031] As an example, the water-absorbing stabilizer may be present in a mass percentage of 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, but is not limited thereto.

[0032] As an example, the mass percentage of the first catalyst is 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or 0.8%, but is not limited thereto.

[0033] In some preferred embodiments, the first polyurethane prepolymer is composed of the following components in weight percentages: 9%~20% first polyisocyanate, 60%~80% polyether polyol, 10%~25% second plasticizer, and 0.01%~0.05% second catalyst.

[0034] As an example, the mass percentage of the first polyisocyanate is 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, 19% or 20%, and is not limited thereto.

[0035] As an example, the mass percentage of the polyether polyol is 60%, 63%, 65%, 68%, 70%, 72%, 75%, 78%, or 80%, and is not limited thereto.

[0036] As an example, the mass percentage of the second plasticizer is 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 17%, 18%, 19%, 20%, 22% or 25%, and is not limited thereto.

[0037] As an example, the mass percentage of the second catalyst is 0.01%, 0.02%, 0.03%, 0.04%, or 0.05%, but is not limited thereto.

[0038] In some preferred embodiments, the first polyisocyanate is one or more of diphenylmethylene diisocyanate, methyl 3-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, and isophthalic diisocyanate.

[0039] In some preferred embodiments, the polyether polyol is a polyether triol with a molar mass of 6000 g / mol to 7000 g / mol. For example, the polyether polyol is a polyether triol with a molar mass of 6000 g / mol, such as Wanhua F3128 and Lanxing Dongda EP3600; or a polyether triol with a molar mass of 7000 g / mol, such as Zhonghua Dongda EP-240 and EXCENOL851.

[0040] In some preferred embodiments, the second plasticizer is at least one selected from phthalates, terephthalates, and alkyl sulfonates. As an example, the second plasticizer is one or more selected from diisooctyl phthalate, diisodecyl phthalate, diisononyl phthalate, dioctyl terephthalate, and alkyl sulfonate Mesamoll.

[0041] In some preferred embodiments, the second catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, 2,2-bismorpholinodiethyl ether, and 1,8-diazacycloundecene.

[0042] In some preferred embodiments, the second polyurethane prepolymer is composed of the following components by mass percentage: 15% to 25% second polyisocyanate, 55% to 70% polycarbonate diol, 15% to 25% third plasticizer, and 0.1% to 0.5% third catalyst; the sum of the mass percentages of all components is 100%.

[0043] As an example, the mass percentage of the second polyisocyanate is 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 22% or 25%, and is not limited thereto.

[0044] As an example, the mass percentage of the polycarbonate diol is 55%, 58%, 60%, 61%, 62%, 63%, 64%, 65%, 65.5%, 66%, 66.5%, 67%, 67.5%, 68%, or 69.9%, and is not limited thereto.

[0045] As an example, the mass percentage of the third plasticizer is 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 20%, 23% or 25%, and is not limited thereto.

[0046] As an example, the mass percentage of the third catalyst is 0.1%, 0.2%, 0.3%, 0.4%, or 0.5%, but is not limited thereto.

[0047] In some preferred embodiments, the second polyisocyanate is one or more of diphenylmethylene diisocyanate, methyl 3-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, and isophthalic diisocyanate.

[0048] In some preferred embodiments, the polycarbonate diol is one or more of the following: polyhexene carbonate diol (CAS No.: 61630-98-6), poly-1,6-hexanediol carbonate diol (CAS No.: 101325-00-2), polycaprolactone hexene carbonate diol (CAS No.: 282534-15-0), polyethylene carbonate diol (CAS No.: 25608-11-1), polypropylene carbonate diol (CAS No.: 31852-84-3), polycyclohexanediol-1,6-hexanediol carbonate diol (CAS No.: 216691-97-3), and poly-1,5-pentanediol-1,6-hexanediol carbonate diol (CAS No.: 132459-81-5).

[0049] In some preferred embodiments, the third plasticizer is at least one selected from phthalates, terephthalates, and alkyl sulfonates. As an example, the third plasticizer is one or more selected from diisooctyl phthalate, diisodecyl phthalate, diisononyl phthalate, dioctyl terephthalate, and alkyl sulfonate Mesamoll.

[0050] In some preferred embodiments, the third catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, 2,2-bismorpholinodiethyl ether, and 1,8-diazacycloundecene.

[0051] In some preferred embodiments, the carbon black has a DBP (dibutyl phthalate) oil absorption value ≥100mL / 100g.

[0052] In some preferred embodiments, the calcium carbonate is calcium carbonate prepared by precipitation.

[0053] In some preferred embodiments, the first plasticizer is at least one of phthalate and alkyl sulfonate. As an example, the first plasticizer is one or more of diisooctyl phthalate, diisodecyl phthalate, diisononyl phthalate, and alkyl sulfonate Mesamoll.

[0054] In some preferred embodiments, the water-absorbing stabilizer is p-toluenesulfonyl isocyanate.

[0055] In some preferred embodiments, the first catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dibutyltin dichloride, and alkylthiodibutyltin Fomrez UL-1.

[0056] Specific embodiments of the present invention also provide a method for preparing the single-component polyurethane windshield sealant, comprising the following steps: S1. Prepare the first polyurethane prepolymer and the second polyurethane prepolymer respectively. S1-1 Synthesis of the first polyurethane prepolymer: Add polyether polyol and second plasticizer to a dry reaction vessel, dehydrate for 1-1.5 h under vacuum (vacuum gauge pressure is -0.1 MPa) at 115℃~125℃, cool down to 55℃~65℃, add the first polyisocyanate and the second catalyst, slowly heat up (e.g., heating rate is 5℃ / min) to 75℃~85℃, keep the reaction under inert gas protection for 3-3.5 h, cool down to temperature <30℃ and discharge the material, and store it in a sealed container for later use.

[0057] S1-2, Synthesis of the second polyurethane prepolymer: Polycarbonate diol and a third plasticizer are added to a dry reaction vessel. The mixture is dehydrated for 1 to 1.5 hours under vacuum (vacuum gauge pressure is -0.1 MPa) at 115℃~125℃. The temperature is then lowered to 55℃~65℃, and a second polyisocyanate and a third catalyst are added. The temperature is slowly increased (e.g., at a rate of 5℃ / min) to 100℃~110℃. The mixture is kept at this temperature for 3 to 3.5 hours under inert gas protection. The mixture is then cooled to <30℃ and discharged into a sealed container for later use.

[0058] S2. The first polyurethane prepolymer, the second polyurethane prepolymer, the carbon black, the calcium carbonate, the first plasticizer, the water-absorbing stabilizer, and the first catalyst are sequentially added to a reaction vessel equipped with a planetary stirrer. Under vacuum (vacuum gauge pressure -0.1 MPa), the mixture is stirred at a rotation speed of 750 rpm to 850 rpm and a revolution speed of 550 rpm to 650 rpm until homogeneous. During stirring, circulating water is used to maintain the temperature of the mixture system ≤68℃. After homogeneous stirring, the mixture is cooled to <30℃, discharged into aluminum tubes for storage. The environment for producing and packaging this single-component polyurethane windshield sealant should be controlled with a temperature ≤35℃ and a relative humidity ≤50%RH; air conditioning and dehumidifiers should be used if necessary.

[0059] Those skilled in the art will understand that the order of steps S1-1 and S1-2 is not limited. The first polyurethane prepolymer and the second polyurethane prepolymer can be synthesized simultaneously, or one can be synthesized first and then the other.

[0060] Example 1 A one-component polyurethane windshield sealant, by weight percentage, comprises the following components: 30% primary polyurethane prepolymer, 15% secondary polyurethane prepolymer, 20% carbon black, 17% calcium carbonate, 16.9% diisononyl phthalate (primary plasticizer), 0.6% p-toluenesulfonyl isocyanate (water-absorbing stabilizer), and 0.5% dibutyltin dilaurate (primary catalyst). The primary polyurethane prepolymer comprises the following components by weight percentage: 11% diphenylmethylene diisocyanate (primary polyisocyanate), 75% polyether triol EP3600 (polyether polyol, Lanxing Dongda) with a molar mass of 6000 g / mol, 13.97% diisononyl phthalate (secondary plasticizer), and 0.03% dibutyltin dilaurate (secondary catalyst). The second polyurethane prepolymer consists of the following components by weight percentage: 19.8% diphenylmethylene diisocyanate (second polyisocyanate), 60% polyhexanediol (polycarbonate diol), 20% diisononyl phthalate (third plasticizer), and 0.2% dibutyltin dilaurate (third catalyst). The carbon black has a DBP oil absorption value ≥100mL / 100g. The calcium carbonate is prepared by precipitation.

[0061] The preparation method of this one-component polyurethane windshield sealant includes the following steps: S1-1 Synthesis of the first polyurethane prepolymer: Polyether polyol and a second plasticizer are added to a dry reaction vessel. The mixture is dehydrated under vacuum (vacuum gauge pressure -0.1 MPa) at 120°C for 1 hour. The temperature is then lowered to 60°C, and a first polyisocyanate and a second catalyst are added. The temperature is slowly increased to 80°C at a rate of 5°C / min. The reaction is maintained at this temperature for 3 hours under inert gas protection. The mixture is then cooled to <30°C and discharged into a sealed container for later use. S1-2 Synthesis of the second polyurethane prepolymer: Polycarbonate diol and a third plasticizer are added to a dry reaction vessel. The mixture is dehydrated under vacuum (vacuum gauge pressure -0.1 MPa) at 120°C for 1 hour. The temperature is then lowered to 60°C, and a second polyisocyanate and a third catalyst are added. The temperature is slowly increased to 100°C at a rate of 5°C / min. The reaction is maintained at this temperature for 3 hours under inert gas protection. The mixture is then cooled to <30°C and discharged into a sealed container for later use.

[0062] S2. The first polyurethane prepolymer, the second polyurethane prepolymer, carbon black, calcium carbonate, the first plasticizer, the water-absorbing stabilizer, and the first catalyst are sequentially added to a reaction vessel equipped with a planetary stirrer. Under vacuum (vacuum gauge pressure -0.1 MPa), the mixture is stirred at a rotation speed of 800 rpm and a revolution speed of 600 rpm until homogeneous. During stirring, circulating water is used to maintain the temperature of the mixture system ≤68℃. After homogeneous stirring, the mixture is cooled to <30℃, discharged into an aluminum tube for storage and later use.

[0063] Example 2 A one-component polyurethane windshield sealant, by weight percentage, comprises the following components: 28% primary polyurethane prepolymer, 19% secondary polyurethane prepolymer, 21% carbon black, 16% calcium carbonate, 14.9% diisononyl phthalate (primary plasticizer), 0.6% p-toluenesulfonyl isocyanate (water-absorbing stabilizer), and 0.5% dibutyltin dilaurate (primary catalyst). The primary polyurethane prepolymer comprises the following components by weight percentage: 9.5% diphenylmethylene diisocyanate (primary polyisocyanate), 66% polyether triol EP-240 (polyether polyol, Sinochem Dongda) with a molar mass of 7000 g / mol, 24.45% diisononyl phthalate (secondary plasticizer), and 0.05% dibutyltin dilaurate (secondary catalyst). The second polyurethane prepolymer consists of the following components by weight percentage: 18.1% diphenylmethylene diisocyanate (second polyisocyanate), 60% polycarbonate-1,6-hexanediol diol (polycarbonate diol), 21.7% diisononyl phthalate (third plasticizer), and 0.2% dibutyltin dilaurate (third catalyst). The carbon black has a DBP oil absorption value ≥100mL / 100g. The calcium carbonate is prepared by precipitation.

[0064] The preparation method of this one-component polyurethane windshield sealant includes the following steps: S1-1 Synthesis of the first polyurethane prepolymer: Polyether polyol and a second plasticizer are added to a dry reaction vessel. The mixture is dehydrated under vacuum (vacuum gauge pressure -0.1 MPa) at 115°C for 1.5 hours. The temperature is then lowered to 55°C, and a first polyisocyanate and a second catalyst are added. The temperature is slowly increased to 75°C at a rate of 5°C / min. The reaction is maintained at this temperature for 3.5 hours under inert gas protection. The mixture is then cooled to <30°C and discharged into a sealed container for later use. S1-2 Synthesis of the second polyurethane prepolymer: Polycarbonate diol and a third plasticizer are added to a dry reaction vessel. The mixture is dehydrated under vacuum (vacuum gauge pressure -0.1 MPa) at 115°C for 1.5 hours. The temperature is then lowered to 55°C, and a second polyisocyanate and a third catalyst are added. The temperature is slowly increased to 105°C at a rate of 5°C / min. The reaction is maintained at this temperature for 3.5 hours under inert gas protection. The mixture is then cooled to <30°C and discharged into a sealed container for later use.

[0065] S2. The first polyurethane prepolymer, the second polyurethane prepolymer, carbon black, calcium carbonate, the first plasticizer, the water-absorbing stabilizer, and the first catalyst are sequentially added to a reaction vessel equipped with a planetary stirrer. Under vacuum (vacuum gauge pressure -0.1 MPa), the mixture is stirred at a rotation speed of 750 rpm and a revolution speed of 650 rpm until homogeneous. During stirring, circulating water is used to maintain the temperature of the mixture system at ≤68℃. After homogeneous stirring, the mixture is cooled to <30℃, discharged into an aluminum tube, and stored for later use.

[0066] Example 3 A one-component polyurethane windshield sealant, by weight percentage, comprises the following components: 32% first polyurethane prepolymer, 16% second polyurethane prepolymer, 21% carbon black, 15% calcium carbonate, 14.9% diisononyl phthalate (first plasticizer), 0.6% p-toluenesulfonyl isocyanate (water-absorbing stabilizer), and 0.5% dibutyltin dichloride (first catalyst). The first polyurethane prepolymer comprises the following components by weight percentage: 10.5% terephthalic acid diisocyanate (first polyisocyanate), 70% polyether triol EXCENOL 851 (polyether polyol) with a molar mass of 7000 g / mol, 19.45% diisononyl phthalate (second plasticizer), and 0.05% stannous octoate (second catalyst). The second polyurethane prepolymer consists of the following components by weight percentage: 19.6% isophthalic dimethyl diisocyanate (second polyisocyanate), 60% polycarbonate-1,5-pentanediol-1,6-hexanediol diol (polycarbonate diol), 20% diisodecyl phthalate (third plasticizer), and 0.4% dibutyltin diacetate (third catalyst). The carbon black has a DBP oil absorption value ≥100mL / 100g. The calcium carbonate is prepared by precipitation.

[0067] The preparation method of this one-component polyurethane windshield sealant includes the following steps: S1-1 Synthesis of the first polyurethane prepolymer: Add polyether polyol and second plasticizer to a dry reaction vessel, dehydrate for 80 min under vacuum (vacuum gauge pressure is -0.1MPa) at 125℃, cool down to 65℃, add the first polyisocyanate and the second catalyst, slowly heat up to 85℃ at a rate of 5℃ / min, keep the reaction under inert gas protection for 3 h, cool down to <30℃ and discharge the material, and store it in a sealed container for later use.

[0068] S1-2, Synthesis of the second polyurethane prepolymer: Polycarbonate diol and the third plasticizer were added to a dry reaction vessel. The mixture was dehydrated for 80 min under vacuum (vacuum gauge pressure was -0.1 MPa) at 125°C. The temperature was then lowered to 65°C, and the second polyisocyanate and the third catalyst were added. The temperature was slowly increased to 110°C at a rate of 5°C / min. The mixture was kept at this temperature for 3 h under inert gas protection. The mixture was then cooled to <30°C and discharged into a sealed container for later use.

[0069] S2. The first polyurethane prepolymer, the second polyurethane prepolymer, carbon black, calcium carbonate, the first plasticizer, the water-absorbing stabilizer, and the first catalyst are sequentially added to a reaction vessel equipped with a planetary stirrer. Stir the mixture under vacuum (vacuum gauge pressure -0.1 MPa) at a rotation speed of 850 rpm and a revolution speed of 550 rpm until homogeneous. During stirring, circulate water to maintain the temperature of the mixture system ≤68℃. After homogeneous stirring, cool to <30℃, discharge into an aluminum tube for storage and later use.

[0070] Comparative Example 1 A single-component polyurethane windshield sealant, by weight percentage, comprises the following components: 45% primary polyurethane prepolymer, 20% carbon black, 17% calcium carbonate, 16.9% diisononyl phthalate (primary plasticizer), 0.6% p-toluenesulfonyl isocyanate (water-absorbing stabilizer), and 0.5% dibutyltin dilaurate (primary catalyst). The primary polyurethane prepolymer comprises the following components by weight percentage: 11% diphenylmethylene diisocyanate (primary polyisocyanate), 75% polyether triol EP3600 (polyether polyol, Lanxing Dongda) with a molar mass of 6000 g / mol, 13.97% diisononyl phthalate (secondary plasticizer), and 0.03% dibutyltin dilaurate (secondary catalyst). The carbon black has a DBP oil absorption value ≥100 mL / 100 g. The calcium carbonate is calcium carbonate prepared by precipitation. The difference between this comparative example and Example 1 is that the single-component polyurethane windshield sealant does not contain a second polyurethane prepolymer, and the mass percentage of the first polyurethane prepolymer is 45%.

[0071] The preparation method of this single-component polyurethane windshield sealant differs from that of Example 1 in that steps S1-2 are omitted, and a second polyurethane prepolymer is not added in step S2; all other steps are the same.

[0072] Comparative Example 2 The difference between the one-component polyurethane windshield sealant provided in this comparative example and Example 2 is that there is no second polyurethane prepolymer, and the mass percentage of the first polyurethane prepolymer is 47%. The preparation method of this one-component polyurethane windshield sealant differs from that of Example 2 in that steps S1-2 are omitted, and the second polyurethane prepolymer is not added in step S2; all other aspects are the same.

[0073] Comparative Example 3 The only difference between the one-component polyurethane windshield sealant provided in this comparative example and Example 1 is that the polyether polyol is polyether triol F3135 (Wanhua Chemical) with a molar mass of 5000 g / mol. The preparation method of this one-component polyurethane windshield sealant is the same as that in Example 1.

[0074] Comparative Example 4 The only difference between the one-component polyurethane windshield sealant provided in this comparative example and Example 1 is that the polyether polyol is polyether triol Changhua CHE-822P with a molar mass of 7500 g / mol. The preparation method of this one-component polyurethane windshield sealant is the same as that in Example 1.

[0075] Product performance testing The performance of the single-component polyurethane windshield sealant provided in Examples 1-3 and Comparative Examples 1-4 was tested. The test methods are as follows, and the test results are shown in Table 1.

[0076] 1. Energy storage modulus test: The test was conducted using a DMA (Dynamic Thermomechanical Analyzer) according to the method in ASTM D4065-2020, with a frequency of 10Hz, an amplitude of 10μm, and equilibrium at 23℃ for 30min.

[0077] 2. Shear strength test: The test shall be conducted in accordance with the method in GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)".

[0078] 3. Tensile strength and elongation at break tests: conducted according to the methods in GB / T 1040.1-2025 "Determination of tensile properties of plastics - Part 1: General".

[0079] Table 1 Performance test results of single-component polyurethane windshield sealant

[0080] As can be seen from Table 1, compared with Examples 1 and 2, Comparative Examples 1 and 2, which used only the first polyurethane prepolymer and not the second polyurethane prepolymer containing polycarbonate diol, showed a significant decrease in shear strength, tensile strength, and storage modulus, but a significant increase in toughness. This indicates that the first polyurethane prepolymer alone cannot achieve the performance indicators of high strength, high toughness, and high modulus. The second prepolymer containing polycarbonate diol makes a significant contribution to improving the strength and modulus of the windshield sealant.

[0081] Table 1 also shows that when the molar mass of the polyether polyol used to prepare the first polyurethane prepolymer is too low, the shear strength, tensile strength, and storage modulus of the prepared polyurethane windshield sealant are slightly improved, but the toughness decreases too much, failing to simultaneously meet the performance indicators of high strength, high toughness, and high modulus. When the molar mass of the polyether polyol used to prepare the first polyurethane prepolymer is too high, the toughness of the prepared polyurethane windshield sealant is significantly improved, but the shear strength, tensile strength, and storage modulus are all significantly reduced, again failing to simultaneously meet the performance indicators of high strength, high toughness, and high modulus. Therefore, controlling the molar mass of the polyether polyol in the first polyurethane prepolymer between 6000 g / mol and 7000 g / mol achieves the optimal performance balance.

[0082] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by anyone skilled in the art. Any simple equivalent changes and modifications made based on the scope of protection claimed in this application and the content of the specification should be included within the scope of protection of this application.

Claims

1. A one-component polyurethane windshield sealant, characterized in that, The product, by mass percentage, comprises the following components: 25%–35% of a first polyurethane prepolymer, 10%–20% of a second polyurethane prepolymer, 18%–25% of carbon black, 15%–20% of calcium carbonate, 15%–25% of a first plasticizer, 0.5%–1% of a water-absorbing stabilizer, and 0.3%–0.8% of a first catalyst; the first polyurethane prepolymer is prepared from a first polyisocyanate and a polyether polyol as the main raw materials, wherein the molar mass of the polyether polyol is 6000 g / mol–7000 g / mol; the second polyurethane prepolymer is prepared from a second polyisocyanate and polycarbonate diol as the main raw materials.

2. The single-component polyurethane windshield sealant according to claim 1, characterized in that, The carbon black has a DBP oil absorption value ≥100mL / 100g; or / and the first plasticizer is at least one of phthalate ester and alkyl sulfonate phenyl ester.

3. The single-component polyurethane windshield sealant according to claim 1, characterized in that, The water-absorbing stabilizer is p-toluenesulfonyl isocyanate; or / and the first catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dibutyltin dichloride, alkylthiodibutyltin Fomrez UL-1.

4. The single-component polyurethane windshield sealant according to claim 1, characterized in that, The first polyurethane prepolymer is composed of the following components in weight percentage: 9%~20% first polyisocyanate, 60%~80% polyether polyol, 10%~25% second plasticizer, and 0.01%~0.05% second catalyst.

5. The single-component polyurethane windshield sealant according to claim 4, characterized in that, The first polyisocyanate is one or more of diphenylmethylene diisocyanate, methyl 3-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, and isophthalic diisocyanate; or / and the polyether polyol is a polyether triol.

6. The single-component polyurethane windshield sealant according to claim 4, characterized in that, The second plasticizer is at least one of phthalate, terephthalate, and alkyl sulfonate; or / and the second catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, 2,2-bismorpholinodiethyl ether, and 1,8-diazacycloundecene.

7. The single-component polyurethane windshield sealant according to claim 1, characterized in that, The second polyurethane prepolymer is composed of the following components by mass percentage: 15%~25% second polyisocyanate, 55%~70% polycarbonate diol, 15%~25% third plasticizer, and 0.1%~0.5% third catalyst; the sum of the mass percentages of all components is 100%.

8. The single-component polyurethane windshield sealant according to claim 7, characterized in that, The second polyisocyanate is one or more of diphenylmethylene diisocyanate, methyl 3-isocyanate-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,5-naphthalene diisocyanate, terephthalic diisocyanate, and isophthalic dimethyl diisocyanate; or / and the polycarbonate diol is one or more of polyhexene carbonate diol, polycarbonate-1,6-hexanediol diol, polycaprolactone hexene diol, polyethylene carbonate diol, polypropylene carbonate diol, polycyclohexanediol-1,6-hexanediol diol, and polycarbonate-1,5-pentanediol-1,6-hexanediol diol.

9. The single-component polyurethane windshield sealant according to claim 7, characterized in that, The third plasticizer is at least one of phthalate, terephthalate, and alkyl sulfonate; or / and the third catalyst is one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, 2,2-bismorpholinodiethyl ether, and 1,8-diazacycloundecene.

10. The method for preparing the single-component polyurethane windshield sealant according to any one of claims 1 to 9, characterized in that, Includes the following steps: The first polyurethane prepolymer, the second polyurethane prepolymer, the carbon black, the calcium carbonate, the first plasticizer, the water-absorbing stabilizer, and the first catalyst are mixed evenly to obtain the single-component polyurethane windshield sealant; the temperature of the mixture system is kept ≤68℃ during the mixing process.

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