All-water foaming polyurethane self-skinning motor cover material and preparation method thereof

Abstract

The invention discloses an all-water-blown polyurethane self-skinning motor cover material and a preparation method thereof.The preparation method of the all-water-blown polyurethane self-skinning motor cover material comprises the steps that polyether polyol with the functionality being 2-4, polymer polyol with the hydroxyl value being 18-32 mgKOH / g, a chain extender, water, a catalyst and a foam stabilizer are evenly mixed to obtain a component A; uniformly mixing isocyanate and a liquid flame retardant to obtain a component B; preparing a component C to obtain a solid flame retardant; the preparation method comprises the following steps: uniformly mixing the component A and the component C, then uniformly mixing the mixture with the component B to obtain a mixture, carrying out mold closing and curing on the mixture, and controlling the mold temperature to be 25-75 DEG C during mold closing and curing. According to the invention, surface urea bond accumulation is realized through matching of solid and liquid flame retardants and surface self-skinning, so that the material can realize a long-period anti-aging effect and a high-efficiency V0-level flame-retardant effect in a high-temperature environment of more than 150 DEG C, and has high thermal aging resistance and flame retardance.

Description

Technical Field

[0001] This invention relates to the field of polyurethane material preparation technology, specifically to a water-foamed polyurethane self-skinning motor cover material and its preparation method. Background Technology

[0002] Polyurethane self-skinning foam, with its advantage of being able to form both the outer skin and core material in a single step, is widely used in automotive steering wheels, engine hoods, bicycle saddles, shoe materials, sporting goods, home armrests, and seats. Current all-water-foamed polyurethane self-skinning motor hood materials utilize all-water foaming technology, where water reacts with isocyanate to produce carbon dioxide gas as the blowing agent. This eliminates the need for physical blowing agents, resulting in a zero ODP value and the absence of volatile organic compounds, significantly improving the material's environmental performance. However, it has certain shortcomings in terms of density, thermal insulation, and self-cleaning properties.

[0003] For electric motors, since the temperature they generate during operation can reach over 100°C, when the aforementioned all-water polyurethane self-skinning foam material is applied to the traditional motor housing, this material is extremely inadequate in achieving long-term aging resistance in high-temperature environments above 150°C. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that the aging resistance at high temperature is insufficient when the currently disclosed all-water polyurethane self-skinning foam material is applied to the traditional motor cover. Thus, the present invention provides an all-water foamed polyurethane self-skinning motor cover material and its preparation method to solve the above problem.

[0005] A method for preparing a water-foamed polyurethane self-skinning motor cover material includes: Component A is prepared by uniformly mixing a polyether polyol with a functionality of 2-4, a polymer polyol with a hydroxyl value of 18-32 mgKOH / g, a chain extender, water, a catalyst, and a foam stabilizer. Component B is prepared by uniformly mixing isocyanate with liquid flame retardant. Preparation of component C to obtain a solid flame retardant; After mixing component A and component C, an A / C combination is obtained. Then, the A / C combination is mixed evenly with component B to obtain a mixture. The mixture is then molded and cured, and the mold temperature is controlled to be maintained at 25-75℃ during the molding and curing process.

[0006] The foaming agent of this invention is water only and does not contain any physical foaming agents.

[0007] Furthermore, the molding curing time is 2-20 minutes; And / or, the temperature during mixing should be controlled at 25-65℃.

[0008] The stirring speed during the preparation of component A is 500-4000 rpm; And / or, the stirring speed during the preparation of component B is 500-4000 rpm; And / or, the stirring speed when the A / C combination is mixed with component B is 1000-4000 rpm, and the stirring time is 5-15 s.

[0009] Furthermore, the mixing speed of component A and component C is 300-3000 rpm.

[0010] As one optional configuration, the composition includes 30-100 parts of polyether polyol, 10-50 parts of polymer polyol, 0.5-3 parts of water, 0.1-10 parts of catalyst, 0.1-5 parts of foam stabilizer, 0.5-10 parts of chain extender, 5-15 parts of solid flame retardant, 50-130 parts of isocyanate, and 5-15 parts of liquid flame retardant.

[0011] Furthermore, component A also includes 1-10 parts of color paste; the color paste is a black or other desired color paste suitable for commercially available polyurethane, such as: Jiasheng 065-1, Baile C19PH079, Baomeishi 4096, etc.

[0012] Specifically, component A includes: Polyether polyol 1, 50-90 parts, preferably 65-85 parts 2,1-10 parts of polyether polyol, preferably 2-8 parts; Polymer polyol, 10-50 parts, preferably 15-25 parts Chain extender, 3-10 parts, preferably 6-10 parts. Foam stabilizer, 0.1-1 part, preferably 0.2-0.6 parts. Catalyst, 0.1-2 parts, preferably 0.3-1 parts, Color paste, 2-8 parts, preferably 3-5 parts Water, 0.5-3 parts, preferably 1-1.5 parts.

[0013] And / or, the content of polymeric polyol in component A is greater than 10%; And / or, the liquid flame retardant accounts for 5-50% of the content of component B, preferably 5-20%; And / or, the mass fraction of isocyanate groups (NCO) in component B is 20-30%, preferably 24-28%; And / or, components A and C are mixed evenly at a mass ratio of A:C = 100:5-15, preferably 100:8-12, to obtain the A / C combination; the A / C combination and component B are mixed evenly at a mass ratio of A / C:B = 100:50-80, preferably 100:65-75.

[0014] As one optional configuration, the polyether polyol is a polyether polyol with a functionality of 2-4, a number-average molecular weight of 2000-8000, and a hydroxyl value of 10-50 mgKOH / g; the polymerization units in the polyether polyol are propylene oxide and ethylene oxide, and based on the total mass of propylene oxide and ethylene oxide, the mass percentage of ethylene oxide is 5%-30%; including but not limited to Wanhua Chemical's F3135, F3156, F3128, F3140, C2020, etc.

[0015] The polymer polyol is a grafted polyether polyol with a hydroxyl value of 18-32 mgKOH / g; the solid content of styrene and acrylonitrile is 30-50%; including but not limited to Wanhua Chemical's POP2140 and POP3630.

[0016] As one optional configuration, the catalyst is triethylenediamine [CAS: 280-57-9], bis(dimethylaminoethyl) ether A1 [CAS: 3931-64-8], stannous octoate [CAS: 3014-55-3], pentamethyldiethylenetriamine ZR40 [CAS: 3939-69-7], trimethylhydroxyethyl ethylenediamine [CAS: 2212-32-0], N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether [CAS: 83016-70-0], 2,2-bismorpholinodiethyl ether [CAS: 7528-24-9], N,N-dimethylcyclohexylamine [CAS: 98-94-2], diethanolamine [CAS: 111-42-2], dimethylaminopropylamine diisopropanol DPA [CAS: One or a mixture of the following: [63469-23-8], bis(3-dimethylaminopropyl)aminoisopropanol ZR50 [CAS: 67151-63-7], dimethylaminoethanol [CAS: 108-01-0], triethylenediamine [CAS: 280-57-9], and N,N-diethylmethylamine [CAS: 614-64-4]; The foam stabilizer includes one or more of the following: polysiloxane-polyoxyolefin copolymer, alkenylsiloxane, fatty acid ester / fatty alcohol polyoxyethylene ether foam stabilizer; including but not limited to SC815, EPK116, B8715, DC6070, TF1348, etc.

[0017] The chain extender is an alcohol chain extender; further, the alcohol chain extender includes one or more of ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,2-pentanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, and neopentanediol.

[0018] The solid flame retardant includes one or more of melamine polyphosphate (MPP), magnesium hydroxide (Mg(OH)2), expanded graphite (EG), hexachlorocyclotriphosphazene (HCCP), ammonium polyphosphate (APP), decabromodiphenyl ether (DecaBDE), tetrabromobisphenol A (TBBPA), aluminum hydroxide (ATH), fluorine-modified nano silica, and amino-modified nano silica; wherein the solid flame retardant accounts for 5-15% of the content of component A, preferably 8-12%.

[0019] As one optional configuration, the liquid flame retardant includes one or more of trichloroisopropyl phosphate (TCPP), triethyl phosphate (TEP), dimethyl methyl phosphate (DMMP), and diethyl ethyl phosphate (DEEP); the liquid flame retardant accounts for 5-50% of the content of component B, preferably 5-20%; And / or, the isocyanate includes one or more of polyphenylmethane polyisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, methylcyclohexyl diisocyanate, isoflurone diisocyanate and naphthalene-1,5-diisocyanate.

[0020] Preferably, the isocyanate is one or more of diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, and urethane-modified diphenylmethane diisocyanate.

[0021] The polymeric diphenylmethane diisocyanate is a polymeric MDI, which is a mixture of polymethylene polyphenyl diisocyanates with different functionalities, with an NCO content of 30-33 wt.% and a functionality of 2.6-3.1; such as Wanhua Chemical's WANNATE PM200.

[0022] The urethane-modified diphenylmethane diisocyanate is generally produced by reacting polyether polyols or polyester polyols with MDI to generate urethane-modified MDI with -NCO terminal groups. The NCO content of the urethane-modified diphenylmethane diisocyanate is 17-25 wt.%, and the functionality is 2-3; for example, Wanhua Chemical's WANNATE 8617, WANNATE 8618, WANNATE 8605, WANNATE 8621, and WANNATE 8623.

[0023] Furthermore, component B includes urethane-modified diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate, wherein the content of urethane-modified diphenylmethane diisocyanate in component B is 60-80%, and the content of polymeric diphenylmethane diisocyanate in component B is 10-40%.

[0024] The present invention also provides a water-foamed polyurethane self-skinning motor cover material, which is prepared by the above-described preparation method.

[0025] The technical solution of this invention has the following advantages: 1. This invention provides a method for preparing a fully water-foamed polyurethane self-skinning motor cover material. Through screening 2-4 functional polyethers and polymeric polyols with hydroxyl values ​​of 18-32 mgKOH / g, and in combination with chain extenders and catalysts, different reaction processes are designed. Combined with a low mold temperature (25-75℃), a high temperature difference (100-120℃) is achieved at the internal reaction center. This results in different reaction rates on the contact mold surface and the formation of specific cell stability imbalances on the surface. After water foaming, the surface layer foaming diffusion rate is greater than the surface film formation rate, causing the foam cell walls to collapse due to their inability to resist gas escape. The process involves fusion to form a dense, non-porous layer with a thickness of 0.3-1.0 mm. Simultaneously, the three-component processing method significantly avoids compatibility issues with solid flame retardants and the resulting production and processing defects. The addition of liquid flame retardants to the isocyanate flame retardant prevents its inactivation in the polyether component. This effectively achieves a three-component system: A (polyether / polyester), B (isocyanate + liquid flame retardant), and C (solid flame retardant), with synergistic liquid-solid flame retardancy, resulting in higher flame retardant performance and an oxygen index >30%. Therefore, through the synergistic combination of structure and components, the final product achieves long-term high-temperature aging resistance. Specifically, this invention achieves surface urea bond stacking through the combination of solid and liquid flame retardants and surface self-skinning, enabling the material to achieve long-term aging resistance and high-efficiency V0-level flame retardancy in high-temperature environments >150℃, combining high heat aging resistance and flame retardant performance.

[0026] 2. This invention uses only water as a foaming agent for the foaming reaction, without using any physical foaming agent in combination. Water has a zero ODP value and is non-toxic and odorless, and does not produce volatile organic compounds, greatly improving the environmental performance of the material and being highly beneficial to industrial production safety. The special foam structure formed by all-water foaming gives the material a low molding filler density, effectively reducing the weight of the motor cover and achieving overall vehicle lightweighting. In addition, all-water foaming replaces physical foaming agents, reducing the use of physical foaming agents and reducing the need for additional physical foaming agent addition steps and equipment investment in the foaming machine, thus achieving cost reduction and efficiency improvement in the process. Detailed Implementation

[0027] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0028] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0029] In the following examples and comparative examples, 1 part by mass = 1 kg.

[0030] Example 1 A method for preparing a water-foamed polyurethane self-skinning motor cover material, the raw materials of which include: (1) Component A: Polyether polyol 1, functionality 3, glycerol-initiated, hydroxyl value 35 mgKOH / g, polymerized from propylene oxide and ethylene oxide; Polyether polyol 2, functionality 2, propylene glycol starting material, hydroxyl value 56 mg KOH / g, propylene oxide polymerization; Grafted polyether polyol 1, functionality 3, glycerol-initiated, hydroxyl value 26 mg KOH / g, polymerized from propylene oxide and ethylene oxide, viscosity 5000-5800 mpa·s, solid content of acrylonitrile and styrene 40%; Grafted polyether polyol 2, functionality 3, glycerol-initiated, hydroxyl value 24 mg KOH / g, polymerized from propylene oxide and ethylene oxide, viscosity 2900-3200 mpa·s, solid content of acrylonitrile and styrene 30%; Foam stabilizer: Polyol-modified polysiloxane WANALYST® SC815 Chain extender: ethylene glycol; Catalysts: Dimethylaminopropylamine diisopropanol (DPA), bis(dimethylaminoethyl) ether (A1), pentamethyldiethylenetriamine (ZR40), bis(3-dimethylaminopropyl)aminoisopropanol (ZR50); Foaming agent: water; Pigment: Black pigment; (2) Component B: Polymeric diphenylmethane diisocyanate: WANNATE PM200, NCO content 31.0 wt%, Wanhua Chemical; Carbamate-modified isocyanate: WANNATE 8617, NCO content 23wt%, Wanhua Chemical.

[0031] Liquid flame retardant: Phosphorus-based flame retardant TCPP; (3) Component C: Solid flame retardant: expanded graphite (≥100 mesh).

[0032] The composition includes 65 parts of polyether polyol 1, 2 parts of polyether polyol 2, 15 parts of grafted polyether polyol 1, 0 parts of grafted polyether polyol 2, 6 parts of chain extender, 0.2 parts of foam stabilizer, 0.25 parts of catalyst A1, 0.1 parts of ZR40, 0.3 parts of ZR50, 0.35 parts of DPA, 1.3 parts of foaming agent, 4 parts of color paste, 25.5 parts of polymerized diphenylmethane diisocyanate, 66.5 parts of urethane-modified isocyanate, 8 parts of liquid flame retardant, and 9.5 parts of solid flame retardant.

[0033] The specific preparation process is as follows: Step 1: Weigh each raw material according to the above proportions and set the temperature inside the mixing vessel to 55℃; Step 2: Add polyether polyol, polymer polyol, catalyst, chain extender, foam stabilizer, color paste and water into the mixing tank in sequence, and mix with a stirrer at 1300 rpm to obtain component A; Step 3: Following the method in Steps 1-2, mix the isocyanate and liquid flame retardant evenly to obtain Component B; Step 4: Mix component A and component C obtained in step 2 at a set ratio and stir at 1500 rpm for 9 seconds to obtain a uniform A / C combination. Then mix component A / C and component B obtained in step 3 at a set ratio and stir at 2500 rpm for 10 seconds, or mix component A / C and component B at a set ratio using a high-pressure foaming machine or a low-pressure foaming machine. Step 5: Quickly pour the mixed materials from Step 4 into the mold, close the mold and allow it to mature for 4.5 minutes to allow the foaming reaction to occur. Open the mold to obtain the all-water foamed polyurethane self-skinning motor cover material. The mold temperature is maintained at 43℃.

[0034] Example 2 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition of the polyether polyol is as follows: 75 parts of polyether polyol 1, 5 parts of polyether polyol 2, 20 parts of grafted polyether polyol 1, 0 parts of grafted polyether polyol 2, 7 parts of chain extender, 0.4 parts of foam stabilizer, 0.25 parts of catalyst A1, 0.2 parts of ZR40, 0.15 parts of ZR50, 0.3 parts of DPA, 1.3 parts of foaming agent, 4 parts of color paste, 25 parts of polymeric diphenylmethane diisocyanate, 65 parts of urethane-modified isocyanate, 10 parts of liquid flame retardant, and 11.4 parts of solid flame retardant.

[0035] The specific preparation process is as follows: Step 1: Weigh each raw material according to the above proportions and set the temperature inside the mixing vessel to 25℃; Step 2: Add polyether polyol, polymer polyol, catalyst, chain extender, foam stabilizer, color paste and water into the mixing tank in sequence, and mix with a stirrer at 500 rpm to obtain component A; Step 3: Following the method in Steps 1-2, mix the isocyanate and liquid flame retardant evenly to obtain Component B; Step 4: Mix component A and component C obtained in step 2 at a set ratio and stir at 300 rpm for 600 seconds to obtain a uniform A / C combination. Then mix component A / C and component B obtained in step 3 at a set ratio and stir at 4000 rpm for 5 seconds, or mix component A / C and component B at a set ratio using a high-pressure foaming machine or a low-pressure foaming machine. Step 5: Quickly pour the mixed materials from Step 4 into the mold, close the mold and allow it to mature for 2 minutes to allow the foaming reaction to occur. Open the mold to obtain the all-water foamed polyurethane self-skinning motor cover material. The mold temperature is maintained at 75℃.

[0036] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0037] Example 3 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition includes 70 parts of polyether polyol 1, 8 parts of polyether polyol 2, 0 parts of grafted polyether polyol 1, 15 parts of grafted polyether polyol 2, 7 parts of chain extender, 0.5 parts of foam stabilizer, 0.3 parts of catalyst A1, 0.5 parts of ZR40, 0.2 parts of ZR50, 0.3 parts of DPA, 1.35 parts of foaming agent, 3 parts of color paste, 20 parts of polymerized diphenylmethane diisocyanate, 70 parts of urethane-modified isocyanate, 10 parts of liquid flame retardant, and 10.6 parts of solid flame retardant.

[0038] The specific preparation process is as follows: Step 1: Weigh each raw material according to the above proportions and set the temperature inside the mixing vessel to 65℃; Step 2: Add polyether polyol, polymer polyol, catalyst, chain extender, foam stabilizer, color paste and water into the mixing tank in sequence, and mix with a stirrer at 4000 rpm to obtain component A; Step 3: Following the method in Steps 1-2, mix the isocyanate and liquid flame retardant evenly to obtain Component B; Step 4: Mix component A and component C obtained in step 2 at a set ratio and stir at 3000 rpm for 5 seconds to obtain a uniform A / C combination. Then mix component A / C and component B obtained in step 3 at a set ratio and stir at 1000 rpm for 15 seconds, or mix component A / C and component B at a set ratio using a high-pressure foaming machine or a low-pressure foaming machine. Step 5: Quickly pour the mixed materials from Step 4 into the mold, close the mold and allow it to mature for 20 minutes to allow the foaming reaction to occur. Open the mold to obtain the all-water-foamed polyurethane self-skinning motor cover material. The mold temperature should be maintained at 25℃.

[0039] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0040] Example 4 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition of the polyether polyol is as follows: 70 parts of polyether polyol 1, 4 parts of polyether polyol 2, 0 parts of grafted polyether polyol 1, 20 parts of grafted polyether polyol 2, 8 parts of chain extender, 0.3 parts of foam stabilizer, 0.15 parts of catalyst A1, 0.2 parts of ZR40, 0.2 parts of ZR50, 0.25 parts of DPA, 1.4 parts of foaming agent, 3 parts of color paste, 30 parts of polymeric diphenylmethane diisocyanate, 60 parts of urethane-modified isocyanate, 10 parts of liquid flame retardant, and 10.8 parts of solid flame retardant.

[0041] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0042] Example 5 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition includes 90 parts of polyether polyol 1, 10 parts of polyether polyol 2, 30 parts of grafted polyether polyol 1, 20 parts of grafted polyether polyol 2, 10 parts of chain extender, 1 part of foam stabilizer, 2 parts of catalyst A1, 3 parts of ZR40, 2 parts of ZR50, 2 parts of DPA, 3 parts of foaming agent, 8 parts of color paste, 90 parts of polymerized diphenylmethane diisocyanate, 30 parts of urethane-modified isocyanate, 15 parts of liquid flame retardant, and 15 parts of solid flame retardant.

[0043] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0044] Example 6 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition includes 50 parts of polyether polyol 1, 1 part of polyether polyol 2, 10 parts of grafted polyether polyol 1, 5 parts of grafted polyether polyol 2, 3 parts of chain extender, 0.1 part of foam stabilizer, 0.1 part of catalyst A1, 0.1 part of ZR40, 0.1 part of ZR50, 0.1 part of DPA, 0.5 parts of foaming agent, 2 parts of color paste, 50 parts of polymerized diphenylmethane diisocyanate, 10 parts of urethane-modified isocyanate, 5 parts of liquid flame retardant, and 5 parts of solid flame retardant.

[0045] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0046] Example 7 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw materials are different, as detailed below: Polyether polyol 1 and polyether polyol 2 are both replaced with polyether polyol F3128, grafted polyether polyol 1 and grafted polyether polyol 2 are both replaced with grafted polyether polyol POP2140, the chain extender is propylene glycol, the foam stabilizer is DC6070, all catalysts are replaced with ZR40, the foaming agent is water, the color paste is Jiasheng 065-1, the isocyanate is WANNATE 8621, the liquid flame retardant is TEP, and the solid flame retardant is melamine polyphosphate (MPP).

[0047] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0048] Example 8 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw materials are different, as detailed below: Polyether polyol 1 and polyether polyol 2 are both replaced with polyether polyol F3156, grafted polyether polyol 1 and grafted polyether polyol 2 are both replaced with grafted polyether polyol POP3630, the chain extender is 1,4-butanediol, the foam stabilizer is EPK116, the catalyst is all replaced with ZR40, the foaming agent is water, the color paste is Bayer C19PH079, the isocyanate is WANNATE8621, the liquid flame retardant is dimethyl methyl phosphate (DMMP), and the solid flame retardant is ammonium polyphosphate (APP).

[0049] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0050] Example 9 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw materials are different, as detailed below: Polyether polyol 1 and polyether polyol 2 are both replaced with polyether polyol F3140, grafted polyether polyol 1 and grafted polyether polyol 2 are both replaced with grafted polyether polyol POP2140, the chain extender is dipropylene glycol, the foam stabilizer is TF1348, the catalyst is all replaced with ZR40, the foaming agent is water, the color paste is Baomeishi 4096, the isocyanate is WANNATE 8623, the liquid flame retardant is diethyl ethyl phosphate (DEEP), and the solid flame retardant is magnesium hydroxide (Mg(OH)2).

[0051] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0052] Example 10 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition includes 70 parts of polyether polyol 1, 15 parts of grafted polyether polyol 2, 8 parts of chain extender, 0.6 parts of foam stabilizer, 0.3 parts of catalyst A1, 0.5 parts of ZR40, 0.2 parts of ZR50, 0.3 parts of DPA, 1.4 parts of foaming agent water, 3 parts of color paste, 50.2 parts of polymerized diphenylmethane diisocyanate, 39.8 parts of urethane-modified isocyanate, 10 parts of liquid flame retardant, and 10.3 parts of solid flame retardant.

[0053] The other parameters and conditions in this embodiment are the same as in Embodiment 1.

[0054] Example 11 The preparation method of the all-water-foamed polyurethane self-skinning motor cover material differs from that in Example 1 in that the raw material ratio is different, as detailed below: The composition of this embodiment is as follows: 79 parts polyether polyol 1, 15 parts grafted polyether polyol 1, 8 parts chain extender, 0.5 parts foam stabilizer, 0.3 parts catalyst A1, 0.5 parts ZR40, 0.2 parts ZR50, 0.3 parts DPA, 1.4 parts foaming agent water, 3 parts color paste, 50.2 parts polymerized diphenylmethane diisocyanate, 34.8 parts urethane-modified isocyanate, 10 parts liquid flame retardant, and 10.3 parts solid flame retardant. Other parameters and conditions in this embodiment are the same as in Example 1.

[0055] Comparative Example 1 The preparation method of the polyurethane motor cover material differs from that of Example 10 in that water is replaced with 6 parts by mass of physical foaming agent HFC-245fa, and the mold temperature is not controlled. Other parameters and conditions are the same as those in Example 10.

[0056] Comparative Example 2 The preparation method of the polyurethane motor cover material differs from that of Example 11 in that water is replaced with 6 parts by mass of physical foaming agent HFC-245fa, and the mold temperature is not controlled. Other parameters and conditions are the same as in Example 11.

[0057] Comparative Example 3 The preparation method of the polyurethane motor cover material differs from that of Example 1 in that the mold temperature is not controlled, while other parameters and conditions are the same as in Example 1.

[0058] Experimental Example The testing methods in Table 1 below were used for detection; Table 1

[0059] The test results are shown in Tables 2 and 3 below.

[0060] Table 2

[0061] Table 3

[0062] The products obtained in Examples 1-11 of the present invention have excellent resistance to dry and humid heat aging under low product density conditions, good dimensional stability under high and low temperature and humid heat aging, and high flame retardancy and low odor characteristics of V0 level.

[0063] A comparison of Examples 1-11 with Comparative Examples 1-3 shows that the low-density conditions of the Examples exhibit superior physical properties compared to the high-density conditions of the Comparative Examples, while maintaining consistent appearance. This demonstrates that all-water foaming significantly reduces product density, thereby reducing casting volume, resulting in a 25-30% weight reduction, meeting the current market demands for lightweight and low-cost passenger vehicles. Furthermore, under the same catalyst content, the Examples demonstrate a lower odor level compared to the Comparative Examples, indicating that the novel formulation proposed in this invention exhibits better environmental friendliness than physically foaming agents. Moreover, under high-temperature dry heat aging and high-temperature high-humidity aging conditions, the attenuation rates of tensile strength, elongation at break, compressive strength, and dimensional shrinkage are significantly reduced. The products prepared using all-water foaming exhibit high heat resistance after both dry heat and wet heat aging, enabling them to withstand various environmental changes and demonstrating excellent weather resistance.

[0064] The synergistic flame retardancy of the solid and liquid flame retardants of this invention can significantly improve the flame retardant performance of the product, enabling the prepared polyurethane self-skinning foam to achieve V0 level flame retardancy and increase the oxygen index to over 30%.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a self-skinning polyurethane motor cover material using all-water foaming, characterized in that, include: Component A is prepared by uniformly mixing a polyether polyol with a functionality of 2-4, a polymer polyol with a hydroxyl value of 18-32 mgKOH / g, a chain extender, water, a catalyst, and a foam stabilizer. Component B is prepared by uniformly mixing isocyanate with liquid flame retardant. Preparation of component C to obtain a solid flame retardant; After mixing component A and component C, an A / C combination is obtained. Then, the A / C combination is mixed evenly with component B to obtain a mixture. The mixture is then molded and cured, and the mold temperature is controlled to be maintained at 25-75℃ during the molding and curing process.

2. The preparation method according to claim 1, characterized in that, The curing time for the mold is 2-20 minutes; And / or, the temperature during mixing should be controlled at 25-65℃.

3. The preparation method according to claim 1 or 2, characterized in that, The stirring speed during the preparation of component A is 500-4000 rpm; And / or, the stirring speed during the preparation of component B is 500-4000 rpm; And / or, the stirring speed used when mixing component A and component C is 300-3000 rpm; And / or, the stirring speed when the A / C combination is mixed with component B is 1000-4000 rpm, and the stirring time is 5-15 s.

4. The preparation method according to any one of claims 1-3, characterized in that, The composition includes 30-100 parts of polyether polyol, 10-50 parts of polymer polyol, 0.5-3 parts of water, 0.1-10 parts of catalyst, 0.1-5 parts of foam stabilizer, 0.5-10 parts of chain extender, 5-15 parts of solid flame retardant, 50-130 parts of isocyanate, and 5-15 parts of liquid flame retardant.

5. The preparation method according to claim 4, characterized in that, Component A also includes 1-10 parts of colorant; And / or, the content of polymeric polyol in component A is greater than 10%.

6. The preparation method according to claim 4, characterized in that, The polyether polyol has a number average molecular weight of 2000-8000 and a hydroxyl value of 10-50 mgKOH / g; the polymerization units in the polyether polyol are propylene oxide and ethylene oxide, and the mass percentage of ethylene oxide is 5%-30% based on the total mass of propylene oxide and ethylene oxide. The polymer polyol is a grafted polyether polyol containing styrene and acrylonitrile, wherein the solid content of styrene and acrylonitrile is 30-50%.

7. The preparation method according to claim 4, characterized in that, The catalyst is one or a mixture of the following: triethylenediamine, stannous octoate, bis(dimethylaminoethyl) ether, pentamethyldiethylenetriamine, trimethylhydroxyethylethylenediamine, N,N,N'-trimethyl-N'-hydroxyethyldiaminoethyl ether, 2,2-bismorpholinodiethyl ether, N,N-dimethylcyclohexylamine, diethanolamine, dimethylaminopropylamine diisopropanol, bis(3-dimethylaminopropyl)aminoisopropanol, dimethylaminoethanol, triethylenediamine, and N,N-diethylmethylamine. The foam stabilizer includes a polysiloxane-polyoxyolefin copolymer; The chain extender is an alcohol-based chain extender; The solid flame retardant includes one or more of the following: melamine polyphosphate, magnesium hydroxide, expanded graphite, hexachlorocyclotriphosphazene, ammonium polyphosphate, decabromodiphenyl ether, tetrabromobisphenol A, aluminum hydroxide, fluorine-modified nano silica, and amino-modified nano silica.

8. The preparation method according to claim 7, characterized in that, The alcohol chain extender includes one or more of ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,2-pentanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, and neopentanediol.

9. The preparation method according to claim 4, characterized in that, The liquid flame retardant includes one or more of trichloroisopropyl phosphate, triethyl phosphate, dimethyl methyl phosphate, and diethyl ethyl phosphate; And / or, the isocyanate is one or more selected from polyphenylmethane polyisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, methylcyclohexyl diisocyanate, isoflurone diisocyanate and naphthalene-1,5-diisocyanate.

10. A self-skinning polyurethane foam motor cover material, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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