A three-component polyurethane liquid, its preparation method and application

Abstract

This invention discloses a three-component polyurethane solution, its preparation method, and its application, relating to the field of polymer material synthesis and application technology. The three-component polyurethane solution comprises component A, component B, and component C. By weight percentage, component A comprises: 91-97% polyether polyol; 2-4% pigment; 1-5% anti-aging agent; 0.1-0.3% blocked bismuth catalyst; and 0.02-0.05% bismuth deblocking aid. Component B comprises: 90-95% small molecule chain extender; 5-10% crosslinking agent; 1-3% acid-blocked amine catalyst; and 0.2-0.5% thermal activation aid. Component C comprises: 88-95% isocyanate; and 5-12% amine-initiated high-functionality polyol. The three-component polyurethane liquid has good fluidity and fast curing speed, which can effectively solve the technical problems of easy glass extrusion and incomplete mold filling in the edging of long-channel panoramic glass of automobiles, as well as the poor delay effect of the catalytic system and long demolding time during long-term casting in low-pressure equipment. It is suitable for low-pressure injection molding process of large-size panoramic glass edging.

Description

Technical Field

[0001] This invention relates to the field of polymer material synthesis and application technology, specifically to a three-component polyurethane liquid, its preparation method, and its application. Background Technology

[0002] With the rapid development of the new energy vehicle industry, panoramic sunroofs are gradually replacing traditional small sunroofs and openable panoramic sunroofs, becoming the mainstream feature of new energy vehicles due to their wide field of vision, good lighting performance, and excellent sense of spatial extension. Industry data shows that the penetration rate of panoramic sunroofs in new energy vehicles has steadily increased in recent years, and the trend of sunroofs becoming more ubiquitous in new energy vehicles is a consensus in the industry, exhibiting a trend of gradually increasing sunroof glass area and increasingly complex edging structures.

[0003] Compared with traditional sunroofs, panoramic sunroofs have significant characteristics: larger area (usually ≥1.5m²), longer edging channels, and mostly narrow channel structures. Some high-end models also have inner and outer double-ring channels. This trend places more stringent requirements on the process adaptability, flowability, and curing characteristics of polyurethane edging materials. Existing polyurethane high-pressure reactive injection molding (RIM) formulations typically have gel times of less than 8 seconds, which meets the short runner production requirements for traditional small sunroof edging. However, when applied to large-size panoramic sunroof edging, they suffer from insurmountable technical shortcomings: The short gel time of the liquid causes a sharp decrease in fluidity, leading to material curing before mold filling is complete. This results in defects such as insufficient material and incomplete edging, affecting product appearance and performance. It also fails to meet the mold filling requirements of large sizes, long perimeters, and narrow runners in panoramic sunroof edging production. Furthermore, the high-pressure closed-mold casting process presents significant flow resistance, easily leading to incomplete mold cavity filling (commonly known in the industry as "insufficient material") and incomplete edging. More seriously, the high-pressure flow can cause localized stress concentration in the glass, potentially causing glass breakage and rendering the product unusable.

[0004] To address the problem of insufficient mold filling, extending the polyurethane reaction induction period and gel time (or open time, flow time) through formulation design is a common technical approach in this field. However, this approach has many limitations in practical applications, making it difficult to balance mold filling effect and production efficiency. CN117700687A discloses a polyurethane elastomer and process for edging skylight glass with an area greater than 1.5m². It adopts a high-pressure reactive injection molding process, extends the flow time by adding pentaerythritol-based polypropylene tetraol, and avoids catalyst deactivation by adding the catalyst on the spot. The flow time is 8-10s, and the demolding time is 25s. This solution has significant shortcomings: the introduction of polypropylene tetraol significantly increases the viscosity of the liquid material and reduces its fluidity, affecting not only the integrity of mold filling and edge coverage, but also easily causing appearance defects such as bubbles and material shortages. Furthermore, the high-pressure injection process still carries the risk of glass cracking. The on-site addition of catalyst increases the number of process steps and raises the difficulty of process control. Moreover, the 8-10s flow time still cannot meet the core requirements of slow gelation and segmented casting in low-pressure injection processes. CN119591831A discloses a slow-gel, fast-curing polyurethane material using a composite catalyst of N,N-dimethylcyclohexylamine and dimethyltin glycolate, achieving a gel time of 10.5 seconds and a demolding time of 30 seconds. The core flaw of this solution lies in its insufficient environmental friendliness and stability: N,N-dimethylcyclohexylamine is a hazardous chemical with high toxicity and odor, and it cannot be completely consumed during the polymerization process. Its residue in the product will worsen the odor and VOC index of the sunroof product, which does not meet the environmental protection requirements for automotive interiors; dimethyltin glycolate has poor hydrolysis resistance and is prone to decomposition reaction during industrial storage and transportation, which leads to a decrease in the material's reactivity, affects the stability of product quality, and increases production risks.

[0005] To achieve a performance balance of "good flow in the early stage and fast curing in the later stage" in polyurethane reactions, "slow at the beginning and fast at the end" catalytic systems have become a research hotspot in this field. The core principle of this type of system is to temporarily deactivate amine or metal catalysts through acid sealing or coordination blocking, and then deactivate and release their activity under heating conditions, thereby achieving delayed catalytic initiation and balancing molding and curing efficiency. However, existing "slow at the beginning and fast at the end" catalytic systems are mostly designed with a single catalyst type, which has problems such as high desealing temperature, slow desealing rate, low desealing efficiency, and insufficient curing speed in the later stage, making it difficult to meet the molding requirements of large-size panoramic canopies and industrial production efficiency. CN102336882B discloses an environmentally friendly and storage-stable reaction injection molding polyurethane composition, which adopts a composite system of organic bismuth catalyst and delayed amine catalyst. The delayed amine catalyst is prepared by mixing and dissolving triethylenediamine and ethylene glycol under heating, and then reacting with salicylic acid. Its gel time can be adjusted in the range of 3 to 30 seconds, with a maximum of 30 seconds, which can meet the molding requirements of large-size parts. However, the demolding time increases significantly with the extension of gel time, reaching up to 10 minutes, which seriously affects the production cycle. CN108892769B discloses an acid-sealed delayed catalyst for the preparation of polyurethane, the raw materials of which include an active tertiary amine, dimethylaminoethyl ether, diethylaminoethanol hexanoate, and mixed organic acids. The patent only uses an acid-sealed delayed amine catalyst. Although it can delay the reaction start time, the curing speed of the single catalyst system is insufficient. In its example, the demolding time at 45°C is as long as 120 seconds, which cannot meet the production requirements of rapid demolding. A single catalyst system is difficult to balance "long gel time" and "short demolding time": In order to achieve full mold filling of large-sized products, when using low-pressure molding process, the gel time needs to be extended to ≥18 seconds. However, existing single acid-sealed delayed amine catalysts or organic bismuth + delayed amine two-component systems will cause a significant decrease in the curing speed in the later stage while extending the gel time, which seriously affects the production efficiency.

[0006] In addition, high-pressure injection molding requires large mold frames and molds, resulting in high equipment investment. Low-pressure injection molding, on the other hand, has good compatibility with large-size, thin-walled glass and can effectively reduce the risk of glass breakage, making it the preferred process for edging large-size panoramic skylights. However, the existing polyurethane formulation system has insufficient fluidity and segmented casting capability, making it difficult to meet the production requirements of long-term continuous casting or multiple segmented casting under low-pressure processes, thus limiting the promotion and application of low-pressure processes in the field of panoramic skylight edging.

[0007] Therefore, developing a polyurethane material and preparation method that combines good early-stage fluidity with fast late-stage curing speed and is compatible with low-pressure injection molding processes is an urgent need in the field to fundamentally solve industry pain points such as high resistance, easy cracking of glass, and low production efficiency in the process of edging panoramic skylight glass. It is also a key direction to promote the development of polyurethane edging materials towards high-end and functional applications. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art. Based on the coordination unsealing mechanism and autocatalytic polymerization theory, it provides a three-component polyurethane liquid, its preparation method, and its application. The liquid has good fluidity and fast curing speed, which can effectively solve the technical problems of easy glass extrusion and incomplete mold filling in the edging of long-channel panoramic sunroof glass of automobiles, as well as the poor delay effect of the catalytic system and long demolding time during long-term casting in low-pressure equipment. It is suitable for the low-pressure injection molding process of edging of large-size panoramic sunroof glass.

[0009] The first aspect of this invention provides a three-component polyurethane liquid, comprising component A, component B, and component C. Component A, by weight percentage, comprises: Polyether polyols 91-97%; Pigment 2-4%; Anti-aging agent 1~5%; Blocked bismuth catalyst 0.1-0.3%; Bismuth unblocking aid 0.02-0.05%; Component B, by weight percentage, comprises: Small molecule chain extenders 90-95%; Crosslinking agent 5~10%; Acid-sealed amine catalyst 1-3%; Thermal activation aid 0.2-0.5%; Component C, by weight percentage, comprises: Isocyanates 88~95%; Amine-based high-functionality polyols: 5-12%; The structural formula of the blocked bismuth catalyst is Bi(R¹-CO-CH-CO-R²). x (RCOO) 3-x Where x takes values ​​from 1.2 to 2; R is an alkyl group with 8 to 13 carbon atoms; R 1 and R 2 They are alkyl, aromatic, and fluoroalkyl groups with 1 to 10 carbon atoms, respectively. 1 and R 2 Same or different.

[0010] Preferably, the polyether polyol is one or more of ethylene oxide-propylene oxide co-ether triols with a primary hydroxyl content ≥70% and a number average molecular weight of 3000-6500.

[0011] Preferably, the pigment is carbon black, and more preferably, it is nano-sized carbon black, wherein the average primary particle size of the nano-sized carbon black is preferably 15~60nm.

[0012] Preferably, the anti-aging agent is one or more of 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327), 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P), bis(3,5-tert-butyl-4-hydroxyphenyl) sulfide (antioxidant 1076), bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (light stabilizer 770), and trioctyl phosphite (auxiliary antioxidant).

[0013] Preferably, the blocked bismuth catalyst is prepared by ligand exchange reaction of bismuth carboxylate and β-diketone. The bismuth carboxylate has the structural formula Bi(RCOO)3, where R is an alkyl group with 8-13 carbon atoms; preferably, the bismuth carboxylate is one or more of bismuth neodecanoate, bismuth isooctanoate, and bismuth tridecanoate; the β-diketone has the structural formula R. 1 -CO-CH2-CO-R 2 R 1 and R 2 They are alkyl, aromatic, and fluoroalkyl groups with 1 to 10 carbon atoms, respectively. 1 and R 2 The same or different; the β-diketone is preferably one or more of acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, and dibenzoylmethane; the molar ratio of bismuth carboxylate to β-diketone is preferably 1:1.2 to 2.0.

[0014] Preferably, the method for preparing the blocked bismuth catalyst includes the following steps: adding β-diketone to a bismuth carboxylate solution, reacting, and distilling after the reaction to obtain the blocked bismuth catalyst. More preferably, the bismuth carboxylate solution is a toluene solution of bismuth carboxylate with a solid content of 30%–50%; the reaction temperature is preferably 60–80°C.

[0015] Preferably, the bismuth unblocking aid is zinc acetylacetonate.

[0016] Preferably, the content of ethylene glycol in the small molecule chain extender is 70-95%, and the remainder is other small molecule chain extenders, preferably one or more of 1,4-butanediol, 1,3-butanediol, diethylene glycol, and dipropylene glycol.

[0017] Preferably, the crosslinking agent is selected from one or more of glycerol, trimethylolethane, trimethylolpropane, and trihydroxyethyl isocyanurate.

[0018] Preferably, the acid-sealed amine catalyst is selected from one or more of triethylenediamine (TEDA)-acetate, TEDA-2-ethylhexanoate, TEDA-neodecanate, triethanolamine-acetate, triethanolamine-ethylhexanoate, and triethanolamine-neodecanate.

[0019] Preferably, the thermal activation aid is iron acetylacetone.

[0020] Preferably, the isocyanate is selected from one or more of diphenylmethane diisocyanate (MDI), liquefied MDI, polymethylene polyphenyl isocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0021] Preferably, the amine-initiated high-functionality polyol has a functionality ≥4 and a number-average molecular weight preferably 300~1000, more preferably 300~600. The amine-initiated high-functionality polyol is preferably one or more of ethylenediamine polyether tetraol, diethylenetriamine polyether pentaol, and toluenediamine polyether tetraol.

[0022] A second aspect of this invention provides a method for preparing a three-component polyurethane liquid, comprising the following steps: 1) Preparation of component A: Mix polyether polyol, pigment carbon black, anti-aging agent, blocked bismuth catalyst, and bismuth unblocking aid evenly; 2) Preparation of component B: Mix the small molecule chain extender, crosslinking agent, acid-sealed amine catalyst, and thermal activation aid evenly; 3) Preparation of component C: Component C is obtained by heating isocyanate and amine as the starting high-functionality polyol; preferably, the reaction temperature is 80~90℃ and the reaction time is preferably 2~3h; 4) Molding: Add components A, B, and C to the corresponding tanks of the low-pressure reaction injection molding equipment, start the pouring mode, and after components A, B, and C are mixed evenly by the mixing head, they are injected into the mold and demolded to obtain the finished product.

[0023] Preferably, when the three-component liquid is poured using a low-pressure reaction injection molding machine, the continuous pouring time is ≥10 minutes; or the segmented pouring time is ≥20 times, with each pouring lasting 30 seconds and an interval of 15 seconds.

[0024] Preferably, the mass ratio of component A, component B, and component C is 100:6~10:40~60.

[0025] The three-component liquid is used for low-pressure reaction injection molding, with a gel time of 18-25 seconds and a demolding time of ≤35 seconds.

[0026] A third aspect of this invention provides an application of a three-component polyurethane liquid, wherein the three-component polyurethane is used to prepare an edge-sealing material for automotive panoramic sunroofs, particularly for large-size panoramic sunroofs. Preferably, the Shore hardness of the automotive panoramic sunroof edge-sealing material is 75A to 95 Shore A.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. Fundamentally solves the problems of glass cracking and difficult molding caused by long flow channels and high resistance: Through a dual-trigger cascade desealing design of a closed bismuth catalytic system in component A and an acid-sealed amine catalytic system in component B, the bismuth desealing aid added to component A effectively reduces the desealing temperature of the bismuth catalyst. Once the temperature reaches the critical point, it rapidly restores the catalytic activity of the closed bismuth catalyst for the isocyanate-hydroxy reaction. Meanwhile, the thermal activation aid added to component B weakens the ionic bond between the carboxylate group and the amine group, promotes the thermal breakage of the carboxylate-amine salt bond, accelerates the release of the free amine catalyst, and improves the desealing efficiency of the amine catalytic system. When components A and B are mixed, the small molecule alcohols (ethylene glycol, butanediol, etc.) in component B and the released free amine catalyst can further promote the rapid desealing of the bismuth catalyst, achieving dual triggering. The cascaded desealing design ensures the orderly activation of catalytic activity, stably controlling the gelation time to 18-25 seconds. It has excellent early-stage fluidity and can fully meet the long-term casting requirements of low-pressure equipment (continuous casting time ≥10min, number of segmented castings (30s each, 15s interval) ≥20 times). During the casting process, the inlet and outlet pressure of the metering pump of the low-pressure equipment remains stable, and the low-pressure molding process can effectively avoid the glass breakage problem caused by high-pressure injection. The low-pressure equipment, through the control of the casting stroke, matches the panoramic canopy runner, which can fully ensure the integrity of the mold filling of large-size, narrow-runner products. It solves the core pain point of the existing high-pressure injection molding process for long-runner products: the material flows into the cavity from the gate area, and the resistance increases during the mold filling process. When the resistance is too high, the glass is squeezed, and the mold filling of the cavity at the far end of the gate area is difficult.

[0028] 2. Bismuth and amine catalysts can also achieve the synergistic effect of the dual catalytic system. At the same time, the isocyanate modified with amine-based high-functionality polyols is used in combination with component C. The self-catalytic effect of its tertiary amine structure can be utilized to accelerate the later cross-linking reaction without the addition of additional catalysts. Moreover, the high-functionality structure can ensure that the material can quickly form a dense cross-linked network, improve the initial strength of the material, and shorten the demolding time to less than 35 seconds. This achieves a performance balance of "long gel and fast curing", taking into account both the molding effect and production efficiency.

[0029] 3. Flexible product hardness adjustment: By adjusting the type and amount of small molecule chain extender in component B, and combining the three-component ratio with the metering pump of low-pressure equipment, the hardness can be adjusted within the range of 75 to 95 Shore A. The same fixed-formulation system can meet the differentiated needs of different customers without the need to readjust the formula or clean the equipment, reducing raw material waste, shortening the development cycle, reducing production costs, and significantly expanding the application scenarios of the product.

[0030] 4. Simple process and good product stability: The preparation method is controllable and does not require complex equipment. At the same time, the components are prepared and stored separately, which can avoid the activity changes caused by premature interaction of catalysts. It has good storage stability, avoids the need for on-site catalyst addition, and reduces the risk of on-site production process. Detailed Implementation

[0031] The present invention will be further described in detail below through specific embodiments, but these embodiments do not limit the scope of protection of the present invention.

[0032] All raw materials used in this embodiment are commercially available conventional products. Unless otherwise specified, they are processed according to conventional procedures. The parts mentioned are by weight. All performance tests are performed in accordance with relevant standards (Shore hardness is tested according to GB / T 531.1, tensile strength and elongation at break are tested according to GB / T 528. Gel time and demolding time are tested according to industry experience methods. Gel time is the time required for the material to be fully mixed until it becomes non-flowing. Demolding time is the shortest time required for the material to fully react to have a certain cohesive strength. The strength formed can ensure that the material does not deform, crack, or bulge after demolding. If the requirements are not met, the demolding time is extended until the demolding conditions are met.) Example 1

[0033] (1) Preparation of blocked bismuth catalyst

[0034] In a dry four-necked flask equipped with a stirrer, reflux condenser, constant-pressure dropping funnel, and nitrogen inlet, 100 parts of bismuth neodecanoate were added, and toluene was added to dilute to a solid content of 40%. The stirrer and reflux condenser were turned on to ensure the reaction system was sealed. At room temperature, 20.8 parts of acetylacetone (bismuth neodecanoate to acetylacetone molar ratio 1:1.5) were added to the constant-pressure dropping funnel and slowly added to the reaction system at a rate of 1-2 drops / second, strictly controlling the dropping rate to prevent the reaction from heating up violently. After the acetylacetone was added, the oil bath was heated to 70°C and stirred at a constant temperature for 2 hours, with reflux of cooling water. During this time, nitrogen was purged to remove small molecule byproducts generated during the reaction. After the reaction was completed, the reaction solution was cooled to room temperature and distilled under reduced pressure at a vacuum of not less than 0.09 MPa and a temperature of 75°C to remove toluene, obtaining a closed bismuth catalyst, which was sealed for later use.

[0035] (2) Preparation of component A

[0036] The above-mentioned ethylene oxide-propylene oxide copolyether triol, pigment carbon black, bis(3,5-tertiary butyl-4-hydroxyphenyl) sulfide, blocked bismuth catalyst, and zinc acetylacetone were added to the reactor. The reactor temperature was controlled at 32°C. The stirring device was turned on and stirred for 95 minutes until the mixture was uniform, resulting in a homogeneous and stable component A, which was then sealed and stored for later use.

[0037] (3) Preparation of component B

[0038] The above-mentioned ethylene glycol, 1,4-butanediol, trimethylolpropane, TEDA-2-ethylhexanoate, and ferric acetylacetone were added to a reaction vessel. The temperature of the reaction vessel was controlled at 32°C. The stirring device was turned on and stirred for 95 minutes until the mixture was uniform, resulting in a homogeneous and stable component B, which was then sealed and stored for later use.

[0039] (4) Preparation of component C

[0040] The MDI and ethylenediamine polyether tetraol were added to a dry reaction vessel, the stirring device was turned on, and the temperature was slowly raised to 85°C. The reaction was carried out for 2.5 hours. During the reaction, the NCO content was measured by sampling (theoretical NCO content 24.6%) to ensure that the reaction reached the expected degree. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, and the product was discharged to obtain component C, which was then sealed and stored for later use.

[0041] (5) Finished product preparation and molding Components A, B, and C were added to their respective material tanks in the low-pressure reactive injection molding equipment. The material temperature in each tank was set to 25°C. The metering pump parameters were adjusted to control the mass ratio of the three components at 100:8:50 (component A:component B:component C = 100:8:50). The casting mode was started, and after the three components were mixed evenly through the mixing head, they were injected into the mold, which had been heated to 70°C. The mixture was demolded after 35 seconds and left at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds per casting, with a 15-second interval) were also measured.

[0042] Example 2

[0043] In Example 2, the metering pump parameters of the equipment were adjusted to control the mass ratio of the three components to be component A: component B: component C = 100: 6: 40. Other steps and parameters were the same as in Example 1.

[0044] Example 3

[0045] In Example 3, the metering pump parameters of the equipment were adjusted to control the mass ratio of the three components to be component A: component B: component C = 100:10:60. Other steps and parameters were the same as in Example 1.

[0046] Example 4

[0047] (1) Preparation of blocked bismuth catalyst In a dry four-necked flask equipped with a stirrer, reflux condenser, constant-pressure dropping funnel, and nitrogen inlet, 100 parts of bismuth isooctanoate were added, and toluene was added to dilute to a solid content of 35%. The stirrer and reflux condenser were turned on to ensure the reaction system was sealed. At room temperature, 29.0 parts of trifluoroacetylacetone (bismuth isooctanoate to trifluoroacetylacetone molar ratio 1:1.2) were added to the constant-pressure dropping funnel and slowly added to the reaction system at a rate of 1-2 drops / second. After the acetylacetone was added, the oil bath was heated to 60°C and stirred at a constant temperature for 2 hours, with reflux of cooling water and nitrogen purging during the process. After the reaction was completed, the reaction solution was cooled to room temperature and distilled under reduced pressure at a vacuum of not less than 0.09 MPa and a temperature of 80°C to remove toluene, yielding a sealed bismuth catalyst, which was then sealed for later use.

[0048] (2) Preparation of component A

[0049] The above-mentioned ethylene oxide-propylene oxide copolyether triol, pigment carbon black, 2-(2'-hydroxy-3'-dodecyl-5'-methylphenyl)benzotriazole, blocked bismuth catalyst, and zinc acetylacetonate were added to a reaction vessel. The reaction vessel temperature was controlled at 30°C. The stirring device was turned on and stirred for 90 minutes until the mixture was uniform, resulting in a homogeneous and stable component A, which was then sealed and stored for later use.

[0050] (3) Preparation of component B

[0051] Add the above-mentioned ethylene glycol, diethylene glycol, glycerol, triethanolamine-acetate, and acetylacetone iron to a reaction vessel, control the reaction vessel temperature at 30°C, turn on the stirring device, and stir for 90 minutes until the mixture is uniform, to obtain a homogeneous and stable component B, which is then sealed and stored for later use.

[0052] (4) Preparation of component C

[0053] The above-mentioned liquefied MDI and toluene diamine polyether tetraol were added to a dry reaction vessel, the stirring device was turned on, and the temperature was slowly raised to 80°C. The reaction was carried out for 3 hours. During the reaction, the NCO content was measured by sampling (theoretical NCO content is 25.4%) to ensure that the reaction reached the expected degree. After the reaction was completed, the mixture was naturally cooled to room temperature, the material was discharged, and component C was obtained. It was then sealed and stored for later use.

[0054] (5) Finished product preparation and molding Components A, B, and C were added to their respective material tanks in the low-pressure reactive injection molding equipment. The material temperature in each tank was set to 22°C. The metering pump parameters were adjusted to control the mass ratio of the three components to 100:8:40 (component A:component B:component C = 100:8:40). The casting mode was started, and after the three components were mixed evenly through the mixing head, they were injected into the mold, which had been heated to 80°C. The mixture was demolded after 35 seconds and left at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds per casting, with a 15-second interval) were also measured.

[0055] Example 5

[0056] (1) Preparation of blocked bismuth catalyst In a dry four-necked flask equipped with a stirrer, reflux condenser, constant-pressure dropping funnel, and nitrogen inlet, 100 parts of bismuth tridecanoate were added, and toluene was added to dilute to a solid content of 45%. The stirrer and reflux condenser were turned on to ensure the reaction system was sealed. At room temperature, 52.8 parts of dibenzoylmethane (bismuth tridecanoate to dibenzoylmethane molar ratio 1:2.0) were loaded into the constant-pressure dropping funnel and slowly added to the reaction system at a rate of 1-2 drops / second. After the addition of acetylacetone was completed, the oil bath was heated to 80°C and stirred at a constant temperature for 2 hours, with reflux of cooling water and nitrogen purging during the process. After the reaction was completed, the reaction solution was cooled to room temperature and distilled under reduced pressure at a vacuum of not less than 0.09 MPa and a temperature of 78°C to remove toluene, yielding a sealed bismuth catalyst, which was sealed for later use.

[0057] (2) Preparation of component A

[0058] The above-mentioned ethylene oxide-propylene oxide copolyether triol, pigment carbon black, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, blocked bismuth catalyst, and zinc acetylacetonate were added to a reaction vessel. The reaction vessel temperature was controlled at 35°C, and the stirring device was turned on. The mixture was stirred for 100 minutes until it was uniformly mixed to obtain a homogeneous and stable component A, which was then sealed and stored for later use.

[0059] (3) Preparation of component B

[0060] Add the above-mentioned ethylene glycol, dipropylene glycol, trimethylolethane, TEDA-neodecanate, and ferric acetylacetone to a reaction vessel, control the reaction vessel temperature at 35°C, turn on the stirring device, and stir for 100 minutes until the mixture is uniform, to obtain a homogeneous and stable component B, which is then sealed and stored for later use.

[0061] (4) Preparation of component C

[0062] Dicyclohexylmethane diisocyanate and diethylenetriamine polyether pentol were added to a dry reaction vessel, the stirring device was turned on, and the temperature was slowly raised to 90°C. The reaction was carried out for 2 hours. During the reaction, the NCO content was measured by sampling (theoretical NCO content 24.0%) to ensure that the reaction reached the expected degree. After the reaction was completed, the mixture was naturally cooled to room temperature, discharged, and component C was obtained. The mixture was then sealed and stored for later use.

[0063] (5) Finished product preparation and molding Components A, B, and C were added to their respective material tanks in the low-pressure reactive injection molding equipment. The material temperature in each tank was set to 28°C. The metering pump parameters were adjusted to control the mass ratio of the three components to 100:8:60 (component A:component B:component C = 100:8:60). The casting mode was started, and after the three components were mixed evenly through the mixing head, they were injected into the mold, which had been heated to 60°C. The mixture was demolded after 35 seconds and left at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds per casting, with a 15-second interval) were also measured.

[0064] Comparative Example 1 (1) Preparation of premixed components A+B

[0065] Add the above components A and B to the reactor at a mass ratio of 100:8, control the temperature at 30°C, turn on the stirring device, and stir for 30 minutes until the mixture is uniform to obtain premixed components A+B, which are then sealed and stored for later use.

[0066] (2) Preparation of component C Component C is the same as in Example 1 (3) Finished product preparation and molding Components A+B and C were added to the corresponding material tanks of the low-pressure reactive injection molding equipment, respectively. The material temperature of each tank was set to 25℃, and the metering pump parameters were adjusted to control the mass ratio of the two components to 100:46 [(A+B):C=100:46]. The casting mode was started, and after the two components were mixed evenly through the mixing head, they were injected into the mold that had been heated to 70℃. After 35 seconds, the components were demolded and placed at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds for each casting, with a 15-second interval) were also measured.

[0067] Comparative Example 2 Components A and B are the same as in Example 1. Component C from Example 1 is replaced with MDI modified with polyether polyol (polypropylene triol, number average molecular weight approximately 300). Component C is prepared as follows:

[0068] The MDI and polyether polyol were added to a dry reaction vessel, the stirrer was turned on, and the temperature was slowly raised to 85°C. The reaction was maintained at this temperature for 2.5 hours. During the reaction, the NCO content was measured (theoretical NCO content 26.0%) to ensure that the reaction reached the expected level. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, and the product was discharged to obtain component C, which was then sealed and stored for later use.

[0069] Finished product preparation and molding Components A, B, and C were added to their respective material tanks in the low-pressure reaction injection molding equipment. The material temperature in each tank was set to 25°C. The metering pump parameters were adjusted to control the mass ratio of the three components to 100:8:47 (A:B:C=100:8:47). The casting mode was started, and after the three components were mixed evenly through the mixing head, they were injected into the mold, which had been heated to 70°C. The mixture was demolded after 35 seconds and left at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds per casting, with a 15-second interval) were also measured.

[0070] Comparative Example 3 Zinc acetylacetone was not added to component A, and iron acetylacetone was not added to component B. Other steps and parameters were the same as in Example 1.

[0071] Comparative Example 4 (1) Preparation of acid-sealed delayed catalyst composition A hydroxylated tertiary amine (a mixture of dimethylethanolamine and trimethylhydroxyethylpropanediamine in a weight ratio of 1:1), dimethylaminoethyl ether, and diethylaminoethanol hexanoate were added to a dry reaction vessel in a weight ratio of 2.2:3.0:1.0. Stirring was started, and the temperature was controlled at 25-35°C. Stirring continued for 30-40 minutes until the system was homogeneous, forming an amine mixture. While stirring, a mixed organic acid (a mixture of isooctanoic acid and gluconic acid in a weight ratio of 1.0:3.2) was slowly added dropwise to the amine mixture. The organic acid was in a weight ratio of 8:1 to diethylaminoacetic acid hexanoate. The dropping rate was controlled at 1-2 drops / second, and the system temperature was maintained at 25-35°C during the dropping process. After the dropping was complete, stirring was continued at a constant temperature for 60-90 minutes to allow the amine and carboxyl groups to react fully, forming an acid-sealed delayed catalyst composition.

[0072] (2) Preparation of component A

[0073] The above-mentioned ethylene oxide-propylene oxide copolyether triol, pigment carbon black, bis(3,5-tertiary butyl-4-hydroxyphenyl) sulfide, ethylene glycol, 1,4-butanediol, trimethylolpropane, and acid-sealed delayed catalyst composition were added to a reactor. The reactor temperature was controlled at 32°C, and the stirring device was turned on. The mixture was stirred for 95 minutes until it was homogeneous, resulting in a uniform and stable component A, which was then sealed and stored for later use.

[0074] (3) Preparation of component C Component C is the same as in Example 1.

[0075] (4) Finished product preparation and molding Component A and component C were added separately to the corresponding material tanks of the low-pressure reactive injection molding equipment. The material temperature of each tank was set to 25℃, and the metering pump parameters were adjusted to control the mass ratio of the two components to 100:50 (A:C=100:50). The casting mode was started, and after the two components were mixed evenly through the mixing head, they were injected into the mold that had been heated to 70℃. After 35 seconds, the mixture was demolded and left at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds per casting, with a 15-second interval) were also measured.

[0076] Comparative Example 5 (1) Preparation of delayed amine catalysts One part of triethylenediamine was mixed with two parts of ethylene glycol or diethylene glycol, heated to 70-80°C and stirred to dissolve, and then 15%-30% by weight of salicylic acid was added. The mixture was stirred at 80°C for 1 hour to obtain a delayed amine catalyst.

[0077] (2) Preparation of component A

[0078] The above-mentioned ethylene oxide-propylene oxide copolyether triol, pigment carbon black, bis(3,5-tertiary butyl-4-hydroxyphenyl) sulfide, ethylene glycol, 1,4-butanediol, trimethylolpropane, delayed amine catalyst, and bismuth neodecanoate were added to a reaction vessel. The reaction vessel temperature was controlled at 32°C, and the stirring device was turned on. The mixture was stirred for 95 minutes until it was uniformly mixed, and a homogeneous and stable component A was obtained. The component A was then sealed and stored for later use.

[0079] (3) Preparation of component C Component C is the same as in Example 1.

[0080] (4) Finished product preparation and molding Component A and component C were added separately to the corresponding material tanks of the low-pressure reactive injection molding equipment. The material temperature of each tank was set to 25℃, and the metering pump parameters were adjusted to control the mass ratio of the two components to 100:50 (A:C=100:50). The casting mode was started, and after the two components were mixed evenly through the mixing head, they were injected into the mold that had been heated to 70℃. After 35 seconds, the mixture was demolded and left at room temperature for 48 hours before performance testing. The continuous casting time and the number of segmented castings (30 seconds per casting, with a 15-second interval) were also measured.

[0081] Comparative Example 6 Remove TEDA-2-ethylhexanoate and ferric acetylacetone from component B in Example 1, and perform the remaining operations as in Example 1.

[0082] Comparative Example 7 Remove the blocked bismuth catalyst and zinc acetylacetonate from component A in Example 1, and perform the remaining operations as in Example 1.

[0083] Comparative Example 8 Replace 100 parts of bismuth neodecanoate and 20.8 parts of acetylacetone in Example 1 with 100 parts of bismuth neodecanoate and 41.6 parts of acetylacetone (molar ratio of bismuth neodecanoate to acetylacetone 1:3), and perform the remaining operations as in Example 1.

[0084] The test results of the examples and comparative examples are shown in Table 1.

[0085] Table 1. Comprehensive comparison between the examples and comparative examples

Claims

1. A three-component polyurethane liquid, comprising component A, component B, and component C, Component A, by weight percentage, comprises: Polyether polyols 91-97%; Pigment 2-4%; Anti-aging agent 1~5%; Blocked bismuth catalyst 0.1-0.3%; Bismuth unblocking aid 0.02-0.05%; Component B, by weight percentage, comprises: Small molecule chain extenders 90-95%; Crosslinking agent 5~10%; Acid-sealed amine catalyst 1-3%; Thermal activation aid 0.2-0.5%; Component C, by weight percentage, comprises: Isocyanates 88~95%; Amine-based high-functionality polyols: 5-12%; The structural formula of the blocked bismuth catalyst is Bi(R¹-CO-CH-CO-R²). x (RCOO) 3-x Where x takes values ​​from 1.2 to 2, and R is an alkyl group with 8 to 13 carbon atoms; R 1 and R 2 They are alkyl, aromatic, and fluoroalkyl groups with 1 to 10 carbon atoms, respectively. 1 and R 2 Same or different.

2. The three-component polyurethane liquid according to claim 1, characterized in that, The polyether polyol is one or more of ethylene oxide-propylene oxide co-ether triols with a primary hydroxyl content ≥70% and a number average molecular weight of 3000-6500.

3. The three-component polyurethane liquid according to claim 1, characterized in that, The blocked bismuth catalyst was prepared by ligand exchange reaction of bismuth carboxylate and β-diketone. Preferably, the bismuth carboxylate has the structural formula Bi(RCOO)3, where R is an alkyl group having 8 to 13 carbon atoms; the bismuth carboxylate is further preferably one or more of bismuth neodecanoate, bismuth isooctanoate, and bismuth tridecanoate. Preferably, the β-diketone has the structural formula R. 1 -CO-CH2-CO-R 2 R 1 and R 2 They are alkyl, aromatic, and fluoroalkyl groups with 1 to 10 carbon atoms, respectively. 1 and R 2 Same or different; the β-diketone is further preferably one or more of acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, and dibenzoylmethane; Preferably, the molar ratio of the bismuth carboxylate to the β-diketone is 1:1.2 to 2.

0.

4. The three-component polyurethane liquid according to claim 1, characterized in that, The bismuth unblocking aid is zinc acetylacetonate, and the thermal activation aid is iron acetylacetonate.

5. The three-component polyurethane liquid according to claim 1, characterized in that, The content of ethylene glycol in the small molecule chain extender is 70-95%, and the remainder is other small molecule chain extenders; the other small molecule chain extenders are preferably one or more of 1,4-butanediol, 1,3-butanediol, diethylene glycol, and dipropylene glycol.

6. The three-component polyurethane liquid according to claim 1, characterized in that, The crosslinking agent is selected from one or more of glycerol, trimethylolethane, trimethylolpropane, and trihydroxyethyl isocyanurate; the isocyanate is selected from one or more of diphenylmethane diisocyanate (MDI), liquefied MDI, polymethylene polyphenyl isocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

7. The three-component polyurethane liquid according to claim 1, characterized in that, The acid-sealed amine catalyst is selected from one or more of triethylenediamine (TEDA)-acetate, TEDA-2-ethylhexanoate, TEDA-neodecanate, triethanolamine-acetate, triethanolamine-ethylhexanoate, and triethanolamine-neodecanate.

8. The three-component polyurethane liquid according to claim 1, characterized in that, The amine-initiated high-functionality polyol has a functionality ≥4 and a number-average molecular weight preferably 300~1000. The amine-initiated high-functionality polyol is preferably one or more of ethylenediamine polyether tetraol, diethylenetriamine polyether pentaol, and toluenediamine polyether tetraol.

9. A method for preparing a three-component polyurethane liquid according to any one of claims 1-8, comprising the following steps: 1) Preparation of component A: Mix polyether polyol, pigment carbon black, anti-aging agent, blocked bismuth catalyst, and bismuth unblocking aid evenly; 2) Preparation of component B: Mix the small molecule chain extender, crosslinking agent, acid-sealed amine catalyst, and thermal activation aid evenly; 3) Preparation of component C: Component C is obtained by heating isocyanate and amine as the starting high-functionality polyols; 4) Molding: Add components A, B, and C to the corresponding tanks of the low-pressure reaction injection molding equipment, start the pouring mode, and after components A, B, and C are mixed evenly by the mixing head, they are injected into the mold and demolded to obtain the finished product. Preferably, the three-component liquid is poured using a low-pressure reaction injection molding machine, with a continuous pouring time of ≥10 minutes; or the pouring time is ≥20 times in segments, each pouring lasts 30 seconds, with an interval of 15 seconds. Preferably, the mass ratio of component A, component B, and component C is 100:6~10:40~60.

10. The application of the three-component polyurethane liquid according to any one of claims 1-9, wherein the three-component polyurethane is used to prepare an edge-sealing material for automotive panoramic sunroof glass.

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