A method for producing a polyurethane composite

Abstract

The application discloses a preparation method of polyurethane composite material and relates to the technical field of high polymer materials. Alkali-free glass fiber square cloth and auxiliary materials including release cloth, flow guide net, flow guide pipe, glue feeding pipe and vacuum film bag are all put into an electric heating constant temperature air drying oven to be preheated and dehydrated, and then taken out; after the reinforcing material and the auxiliary material are laid according to the process sequence of vacuum infusion forming, the vacuum film bag is sealed, the treated polyurethane glue solution is injected, and after complete solidification at room temperature, the polyurethane composite material is put into the electric heating constant temperature air drying oven for post-solidification, and after natural cooling, the polyurethane composite material is trimmed by a cutting machine. The polyurethane composite material prepared by the method has excellent mechanical properties and waterproof performance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and specifically to a method for preparing a polyurethane composite material. Background Technology

[0002] Polyurethane resin, as a matrix for composite materials, differs from unsaturated polyester resin, vinyl ester resin, and epoxy resin, which are commonly used resins with relatively mature and complete processes for manufacturing composite materials.

[0003] Because polyurethane resin is highly reactive, and the resin impregnation time for continuous fiber fabric in composite molding processes is relatively long, a polyurethane matrix with a long pot life, suitable viscosity, and a room temperature gelation time of at least 30 minutes should be selected to successfully prepare continuous glass fiber woven fabric reinforced polyurethane composites. Furthermore, for composite products to achieve complete shape, uniform appearance and physical properties, the resin raw material must possess good flowability.

[0004] Besides the high reactivity of isocyanate groups with polyols severely restricting the development of polyurethane composites, the high reactivity of isocyanate groups with trace amounts of moisture also affects the development of polyurethane composite processes. Furthermore, the complete impregnation of continuous glass fiber woven fabric with polyurethane resin is a slow process, requiring significantly more time compared to impregnating chopped fibers, long fibers, and glass mats. This prolonged impregnation process further exacerbates the reaction between isocyanate groups and moisture. For these reasons, currently, both domestically and internationally, chopped fibers, long fibers, and continuous mats are more commonly used as reinforcing materials to prepare polyurethane foamed or non-foamed composites. Manufacturing processes include RRIM (Reactive Reinforcement Injection Molding) and SRIM (Structural Reinforcement Injection Molding), high-speed spray molding, compression molding, pultrusion molding, and filament winding. Research and performance information on continuous glass fiber woven fabric reinforced polyurethane composites are relatively scarce both domestically and internationally. However, unlike chopped or long fiber reinforced composites, continuous glass fiber woven fabric, as a continuous reinforcing material, exhibits significantly higher mechanical properties than chopped or long fiber reinforced polyurethane composites. Therefore, the future development of continuous fiber reinforced polyurethane composites has significant industrial application implications.

[0005] The basic steps of the vacuum infusion process are as follows:

[0006] (1) Design and fabricate a single-sided rigid mold that has good airtightness and rigidity.

[0007] (2) Prepare molds and related materials, including cleaning and waxing the molds, cutting reinforcing and auxiliary materials, and preparing the resin curing system.

[0008] (3) Lay out reinforcing and auxiliary materials. The layering sequence from bottom to top is: reinforcing material → release cloth → flow guide net → flow guide pipe.

[0009] (4) Cover with a vacuum film bag with an inlet tube and an air extraction port, and seal the reinforcing material and auxiliary material inside the vacuum film bag with sealing tape.

[0010] (5) Start the vacuum pump to evacuate and check the air tightness. After confirming that there is no air leakage, ensure that the mold cavity reaches a certain vacuum level (the optimal value is above -0.095MPa).

[0011] (6) Inject resin to ensure that the resin fully wets the reinforcing material and fills the entire mold before gelation. Excess resin is collected in the resin collector between the evacuation port and the vacuum pump.

[0012] (7) Curing and molding: Before the resin gel is cured, it is still necessary to maintain the vacuum degree so that the vacuum film bag can press the reinforcing material to ensure that the product achieves a high fiber volume content.

[0013] (8) Post-demolding treatment, including cleaning auxiliary materials such as demolding cloth, flow guide net, and vacuum film bag, and demolding and trimming.

[0014] (9) Obtain the product.

[0015] Vacuum infusion molding, as a fully closed-mold molding process, utilizes the negative pressure generated by vacuum to allow resin to penetrate and flow, achieving resin impregnation of fibers and fabrics. The entire process is not only clean, environmentally friendly, and efficient, but also produces products with stable quality and performance. Furthermore, it effectively prevents moisture and air from entering the mold, preventing isocyanate groups from reacting with water to generate bubbles. At the same time, the addition of EO / PO random block fatty acid methyl ester ethoxylate (FMEE) makes it difficult for bubbles in the system to maintain their original shape, causing them to rupture and resulting in a dense structure in the product. Finally, the synergistic effect of four chain extenders further enhances the hydrophobicity of the waterborne polyurethane material without reducing its strength or toughness. Summary of the Invention

[0016] The purpose of this invention is to provide a method for preparing polyurethane composite materials to solve the problems mentioned in the background art.

[0017] To achieve the above objectives, the present invention provides the following technical solution:

[0018] A method for preparing a polyurethane composite material includes the following preparation steps:

[0019] (1) By weight, take 30-40 parts of polytetrahydrofuran ether diol, 20-30 parts of polycaprolactone diol, 80-100 parts of isophorone diisocyanate, 0.02-0.03 parts of catalyst, 5-8 parts of chain extender A, 5-8 parts of chain extender B, 5-8 parts of chain extender C, 5-8 parts of chain extender D, 1-2 parts of ultraviolet absorber, 0.5-0.8 parts of antioxidant, and 3-5 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0020] (2) Polytetrahydrofuran ether diol, polycaprolactone diol, and isophorone diisocyanate were placed in a reaction vessel. A catalyst was then added to the reaction vessel. The mixture was stirred for 30-40 minutes under a nitrogen atmosphere at 80-90°C and a rotation speed of 600-800 r / min. Chain extender A was then added, and the mixture was stirred for 2-3 hours at 80-90°C and a rotation speed of 600-800 r / min. Chain extender B was then added, and the mixture was stirred for 2 hours at 80-90°C and a rotation speed of 600-800 r / min. Under conditions of 800 r / min, stir and react for 1-2 h, then cool to 50-60℃ and react for 1-2 h, then add chain extender C and react for 1-2 h, then add chain extender D and react for 30-40 min, then add triethylamine to neutralize for 30-40 min, and finally add ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE; stir and mix at 600-800 r / min for 40-60 min to obtain polyurethane adhesive;

[0021] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0022] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive.

[0023] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0024] As a preferred option, the catalyst in step (1) is dibutyltin dilaurate.

[0025] Preferably, in step (1), chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:3 to 1:5.

[0026] Preferably, the chain extender B in step (1) is 1,4-butanediol.

[0027] Preferably, the chain extender C in step (1) is 1,3-dihydroxymethylurea.

[0028] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0029] Preferably, the ultraviolet absorber in step (1) is any one of Sumisorb 110, Sumisorb 130, Sumisorb 140, Sumisorb 220, Sumisorb 250, and Sumisorb 300.

[0030] Preferably, the antioxidant in step (1) is any one of Irganox1010, Irganox1035, Irganox1076, and Irganox1222.

[0031] In summary, due to the adoption of the above-mentioned technologies, the beneficial effects of this invention are:

[0032] (1) Using small molecules 2,2-dihydroxymethylbutyric acid and 1,4-butanediol in combination with 1,3-dihydroxymethylurea, the characteristic of 1,3-dihydroxymethylurea is that the urea group is located inside the molecule, and the active hydroxyl groups at both ends are the reaction sites. In the chain extension reaction of diol and -NCO, it not only has an appropriate reaction rate to ensure stable chain extension and subsequent dispersion, but also is easy to work synergistically with other hydroxyl chain extenders and is used for different chain extension reactions. At the same time, the mixed polyol based on polytetramethylene ether and polycaprolactone diol is used as a macromolecular diol to further improve water resistance and flexibility. The aminopropyl-terminated polydimethylsiloxane is used as the chain extender in the fourth chain extension reaction to further improve the hydrophobicity of the waterborne polyurethane material, while the strength and toughness are not reduced.

[0033] (2) By adding EO / PO random block fatty acid methyl ester ethoxylated compound FMEE, EO / PO random block FMEE has good hard surface spreading performance, increases the fluidity of the resin, does not aggregate on the glass fiber surface, and can spread quickly on the glass fiber surface. At the same time, after ethoxylation, it is further propoxylated, and the molecular structure contains both hydrophilic ethoxy and lipophilic propoxy. This alternating arrangement of hydrophilic and lipophilic structures makes it difficult for bubbles in the system to maintain their original shape and break down, resulting in a dense structure in the product, thereby enhancing the water resistance and mechanical properties of the system. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] A method for preparing a polyurethane composite material includes the following preparation steps:

[0037] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 30 parts of polycaprolactone diol, 80 parts of isophorone diisocyanate, 0.03 parts of catalyst, 5 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 5 parts of chain extender D, 2 parts of ultraviolet absorber, 0.8 parts of antioxidant, and 3 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0038] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel. Then a catalyst was added to the reaction vessel. The reaction was carried out under a nitrogen atmosphere at a temperature of 80°C and a rotation speed of 800 r / min for 40 min. Then chain extender A was added. The reaction was carried out under a temperature of 90°C and a rotation speed of 600 r / min for 3 h. Then chain extender B was added. The reaction was carried out under a temperature of 90°C and a rotation speed of 800 r / min for 2 h. Then the temperature was lowered to 50°C and the reaction was carried out for 2 h. Then chain extender C was added and the reaction was carried out for 1 h. Then chain extender D was added and the reaction was carried out for 40 min. Then triethylamine was added for neutralization for 40 min. Finally, ultraviolet absorber, antioxidant, EO / PO random block fatty acid methyl ester ethoxylate compound FMEE was added. The mixture was stirred and mixed at a rotation speed of 800 r / min for 40 min to obtain polyurethane adhesive.

[0039] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0040] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive.

[0041] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0042] The catalyst in step (1) is dibutyltin dilaurate.

[0043] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:3.

[0044] In step (1), chain extender B is 1,4-butanediol.

[0045] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0046] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0047] Step (1) The ultraviolet absorber is Sumisorb 110.

[0048] Step (1) The antioxidant is Irganox 1010.

[0049] Example 2

[0050] A method for preparing a polyurethane composite material includes the following preparation steps:

[0051] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 90 parts of isophorone diisocyanate, 0.03 parts of catalyst, 7 parts of chain extender A, 6 parts of chain extender B, 8 parts of chain extender C, 8 parts of chain extender D, 1 part of ultraviolet absorber, 0.8 parts of antioxidant, and 5 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0052] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel. Then a catalyst was added to the reaction vessel. The reaction was carried out under a nitrogen atmosphere at a temperature of 80°C and a rotation speed of 700 r / min for 40 min. Then chain extender A was added. The reaction was carried out under a temperature of 80°C and a rotation speed of 800 r / min for 3 h. Then chain extender B was added. The reaction was carried out under a temperature of 80°C and a rotation speed of 600 r / min for 2 h. Then the temperature was lowered to 50°C and the reaction was carried out for 1 h. Then chain extender C was added and the reaction was carried out for 2 h. Then chain extender D was added and the reaction was carried out for 30 min. Then triethylamine was added to neutralize for 40 min. Finally, ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE were added. The mixture was stirred and mixed at a rotation speed of 700 r / min for 40 min to obtain polyurethane adhesive.

[0053] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0054] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive.

[0055] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0056] The catalyst in step (1) is dibutyltin dilaurate.

[0057] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:5.

[0058] In step (1), chain extender B is 1,4-butanediol.

[0059] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0060] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0061] Step (1) The ultraviolet absorber is Sumisorb 300.

[0062] Step (1) The antioxidant is Irganox 1076.

[0063] Example 3

[0064] A method for preparing a polyurethane composite material includes the following preparation steps:

[0065] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 100 parts of isophorone diisocyanate, 0.02 parts of catalyst, 7 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 8 parts of chain extender D, 2 parts of ultraviolet absorber, 0.5 parts of antioxidant, and 4 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0066] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel. Then a catalyst was added to the reaction vessel. The reaction was carried out under a nitrogen atmosphere at a temperature of 90°C and a rotation speed of 600 r / min for 40 min. Then chain extender A was added. The reaction was carried out under a temperature of 90°C and a rotation speed of 700 r / min for 3 h. Then chain extender B was added. The reaction was carried out under a temperature of 85°C and a rotation speed of 800 r / min for 1 h. Then the temperature was lowered to 60°C and the reaction was carried out for 1 h. Then chain extender C was added and the reaction was carried out for 2 h. Then chain extender D was added and the reaction was carried out for 40 min. Then triethylamine was added to neutralize for 40 min. Finally, ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE were added. The mixture was stirred and mixed at a rotation speed of 700 r / min for 50 min to obtain polyurethane adhesive.

[0067] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0068] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.1MPa, start injecting the pre-treated polyurethane adhesive.

[0069] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0070] The catalyst in step (1) is dibutyltin dilaurate.

[0071] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:3.

[0072] In step (1), chain extender B is 1,4-butanediol.

[0073] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0074] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0075] Step (1) The ultraviolet absorber is Sumisorb 250.

[0076] Step (1) The antioxidant is Irganox 1222.

[0077] Comparative Example 1

[0078] A method for preparing a polyurethane composite material includes the following preparation steps:

[0079] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 100 parts of isophorone diisocyanate, 0.02 parts of catalyst, 7 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 8 parts of chain extender D, 2 parts of ultraviolet absorber, and 0.5 parts of antioxidant.

[0080] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel. Then a catalyst was added to the reaction vessel. The reaction was carried out under a nitrogen atmosphere at a temperature of 90°C and a rotation speed of 600 r / min for 40 min. Then chain extender A was added. The reaction was carried out under a temperature of 90°C and a rotation speed of 700 r / min for 3 h. Then chain extender B was added. The reaction was carried out under a temperature of 85°C and a rotation speed of 800 r / min for 1 h. Then the temperature was lowered to 60°C and the reaction was carried out for 1 h. Then chain extender C was added and the reaction was carried out for 2 h. Then chain extender D was added and the reaction was carried out for 40 min. Then triethylamine was added to neutralize for 40 min. Finally, ultraviolet absorber and antioxidant were added. The mixture was stirred and mixed for 50 min at a rotation speed of 700 r / min to obtain polyurethane adhesive.

[0081] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0082] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive.

[0083] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0084] The catalyst in step (1) is dibutyltin dilaurate.

[0085] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:5.

[0086] In step (1), chain extender B is 1,4-butanediol.

[0087] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0088] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0089] Step (1) The ultraviolet absorber is Sumisorb 250.

[0090] Step (1) The antioxidant is Irganox 1222.

[0091] Comparative Example 2

[0092] A method for preparing a polyurethane composite material includes the following preparation steps:

[0093] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 100 parts of isophorone diisocyanate, 0.02 parts of catalyst, 7 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 8 parts of chain extender D, 2 parts of ultraviolet absorber, 0.5 parts of antioxidant, and 4 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0094] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel, and then a catalyst was added to the reaction vessel. Under a nitrogen atmosphere, at a temperature of 90°C and a rotation speed of 600 r / min, the mixture was stirred for 40 min. Then chain extender B was added, and the mixture was stirred for 1 h at a temperature of 85°C and a rotation speed of 800 r / min. Then the temperature was lowered to 60°C and the mixture was stirred for 1 h. Then chain extender C was added and the mixture was stirred for 2 h. Then chain extender D was added and the mixture was stirred for 40 min. Then triethylamine was added to neutralize the mixture for 40 min. Finally, ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE were added. The mixture was stirred and mixed for 50 min at a rotation speed of 700 r / min to obtain polyurethane adhesive.

[0095] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0096] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive.

[0097] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0098] The catalyst in step (1) is dibutyltin dilaurate.

[0099] In step (1), chain extender B is 1,4-butanediol.

[0100] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0101] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0102] Step (1) The ultraviolet absorber is Sumisorb 250.

[0103] Step (1) The antioxidant is Irganox 1222.

[0104] Comparative Example 3

[0105] A method for preparing a polyurethane composite material includes the following preparation steps:

[0106] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 100 parts of isophorone diisocyanate, 0.02 parts of catalyst, 7 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 8 parts of chain extender D, 2 parts of ultraviolet absorber, 0.5 parts of antioxidant, and 4 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0107] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel, and then a catalyst was added to the reaction vessel. Under a nitrogen atmosphere, at a temperature of 90°C and a rotation speed of 600 r / min, the mixture was stirred for 40 min. Then chain extender A was added, and under a temperature of 90°C and a rotation speed of 700 r / min, the mixture was stirred for 3 h. Then chain extender C was added, and the mixture was stirred for 2 h. Then chain extender D was added, and the mixture was stirred for 40 min. Then triethylamine was added to neutralize the mixture for 40 min. Finally, ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE were added. The mixture was stirred and mixed for 50 min at a rotation speed of 700 r / min to obtain polyurethane adhesive.

[0108] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0109] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive.

[0110] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0111] The catalyst in step (1) is dibutyltin dilaurate.

[0112] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:5.

[0113] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0114] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0115] Step (1) The ultraviolet absorber is Sumisorb 250.

[0116] Step (1) The antioxidant is Irganox 1222.

[0117] Comparative Example 4

[0118] A method for preparing a polyurethane composite material includes the following preparation steps:

[0119] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 100 parts of isophorone diisocyanate, 0.02 parts of catalyst, 7 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 8 parts of chain extender D, 2 parts of ultraviolet absorber, 0.5 parts of antioxidant, and 4 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0120] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel. Then a catalyst was added to the reaction vessel. The reaction was carried out under a nitrogen atmosphere at a temperature of 90°C and a rotation speed of 600 r / min for 40 min. Then chain extender A was added. The reaction was carried out under a temperature of 90°C and a rotation speed of 700 r / min for 3 h. Then chain extender B was added. The reaction was carried out under a temperature of 85°C and a rotation speed of 800 r / min for 1 h. Then the temperature was lowered to 60°C and the reaction was carried out for 1 h. Then chain extender D was added and the reaction was carried out for 40 min. Then triethylamine was added to neutralize for 40 min. Finally, ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE were added. The mixture was stirred and mixed at a rotation speed of 700 r / min for 50 min to obtain polyurethane adhesive.

[0121] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0122] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.1MPa, start injecting the pre-treated polyurethane adhesive.

[0123] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0124] The catalyst in step (1) is dibutyltin dilaurate.

[0125] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:3.

[0126] In step (1), chain extender B is 1,4-butanediol.

[0127] Preferably, in step (1), the chain extender D is an aminopropyl-terminated polydimethylsiloxane.

[0128] Step (1) The ultraviolet absorber is Sumisorb 250.

[0129] Step (1) The antioxidant is Irganox 1222.

[0130] Comparative Example 5

[0131] A method for preparing a polyurethane composite material includes the following preparation steps:

[0132] (1) By weight, take 40 parts of polytetrahydrofuran ether diol, 20 parts of polycaprolactone diol, 100 parts of isophorone diisocyanate, 0.02 parts of catalyst, 7 parts of chain extender A, 8 parts of chain extender B, 5 parts of chain extender C, 8 parts of chain extender D, 2 parts of ultraviolet absorber, 0.5 parts of antioxidant, and 4 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE;

[0133] (2) Polytetrahydrofuran ether diol, polycaprolactone diol and isophorone diisocyanate were placed in a reaction vessel. Then a catalyst was added to the reaction vessel. The reaction was carried out under a nitrogen atmosphere at a temperature of 90°C and a rotation speed of 600 r / min for 40 min. Then chain extender A was added. The reaction was carried out under a temperature of 90°C and a rotation speed of 700 r / min for 3 h. Then chain extender B was added. The reaction was carried out under a temperature of 85°C and a rotation speed of 800 r / min for 1 h. Then the temperature was lowered to 60°C and the reaction was carried out for 1 h. Then chain extender C was added and the reaction was carried out for 2 h. Then triethylamine was added for neutralization for 40 min. Finally, ultraviolet absorber, antioxidant, EO / PO random block fatty acid methyl ester ethoxylate compound FMEE was added. The mixture was stirred and mixed at a rotation speed of 700 r / min for 50 min to obtain polyurethane adhesive.

[0134] (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out.

[0135] (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.1MPa, start injecting the pre-treated polyurethane adhesive.

[0136] (5) After complete curing at room temperature, place it in an 80°C electric constant temperature drying oven for 2 hours and then cool naturally before removing the burrs with a cutting machine.

[0137] The catalyst in step (1) is dibutyltin dilaurate.

[0138] Step (1) Chain extender A is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:3.

[0139] In step (1), chain extender B is 1,4-butanediol.

[0140] Step (1) Chain extender C is 1,3-dihydroxymethylurea.

[0141] Step (1) The ultraviolet absorber is Sumisorb 250.

[0142] Step (1) The antioxidant is Irganox 1222.

[0143] Detection method:

[0144] (1) Static mechanical properties

[0145] The polyurethane composite materials prepared in Examples 1-3 and Comparative Examples 1-5 were prepared using an SD3025M universal sample preparation machine. The sheets were prepared into 15mm×120mm bending specimens according to GB / T1449--2005, and Type I dumbbell-shaped tensile specimens were prepared according to GB / T1447-2005. Five specimens were prepared for each material for testing and the average value was taken.

[0146] (2) Density test

[0147] Density tests were performed using an AG 2.85 g / 10,000 electronic analytical balance and a density measuring component, employing the buoyancy method. Based on Archimedes' principle, the volume of the specimen was calculated using buoyancy, and the density of the specimen material was obtained by dividing its mass in air by its volume. Five specimens were prepared for each material, and the average value was taken.

[0148] Table 1

[0149]

[0150] As can be seen from the comparative examples 1-2 and 1 in Table 1, by adding the EO / PO random block fatty acid methyl ester ethoxylated compound FMEE, the EO / PO random block FMEE exhibits good hard surface spreading properties, increases resin fluidity, does not aggregate on the glass fiber surface, and can quickly spread on the glass fiber surface. Simultaneously, after ethoxylation, further propoxylation occurs, resulting in a molecular structure containing both hydrophilic ethoxy and lipophilic propoxy groups. This alternating arrangement of hydrophilic and lipophilic structures makes it difficult for bubbles in the system to maintain their original shape, leading to a dense structure and thus enhancing the system's water resistance and mechanical properties. As can be seen from the comparison between Examples 1-3 and Comparative Examples 2-5 in Table 1, using small... The combination of 2,2-dimethylolbutyric acid and 1,4-butanediol with 1,3-dihydroxymethylurea, characterized by the urea group located inside the molecule and the active hydroxyl groups at both ends serving as reaction sites, not only provides an appropriate reaction rate in the chain extension reaction between the glycol and -NCO to ensure stable chain extension and subsequent dispersion, but also facilitates synergistic effects with other hydroxyl chain extenders for different chain extension reactions. Simultaneously, the application of a mixed polyol based on polytetramethylene ether and polycaprolactone diol as a macromolecular diol further enhances water resistance and flexibility. The aminopropyl-terminated polydimethylsiloxane, as a chain extender in the fourth chain extension reaction, further improves the hydrophobicity of the waterborne polyurethane material without reducing strength or toughness.

[0151] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0152] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

Claims

1. A method for preparing a polyurethane composite material, characterized in that, The preparation steps include the following: (1) By weight, take 30-40 parts of polytetrahydrofuran ether diol, 20-30 parts of polycaprolactone diol, 80-100 parts of isophorone diisocyanate, 0.02-0.03 parts of catalyst, 5-8 parts of chain extender A, 5-8 parts of chain extender B, 5-8 parts of chain extender C, 5-8 parts of chain extender D and 1-2 parts of ultraviolet absorber, 0.5-0.8 parts of antioxidant, and 3-5 parts of EO / PO random block fatty acid methyl ester ethoxylate compound FMEE; (2) Polytetrahydrofuran ether diol, polycaprolactone diol, and isophorone diisocyanate were placed in a reactor. A catalyst was then added to the reactor. The mixture was stirred for 30-40 minutes under a nitrogen atmosphere at 80-90°C and a rotation speed of 600-800 r / min. Chain extender A was then added, and the mixture was stirred for 2-3 hours at 80-90°C and a rotation speed of 600-800 r / min. Finally, chain extender B was added, and the mixture was stirred for 2 hours at 80-90°C and a rotation speed of 600-800 r / min. Under conditions of 800 r / min, stir and react for 1-2 h, then cool to 50-60℃ and react for 1-2 h, then add chain extender C and react for 1-2 h, then add chain extender D and react for 30-40 min, then add triethylamine to neutralize for 30-40 min, and finally add ultraviolet absorber, antioxidant, and EO / PO random block fatty acid methyl ester ethoxylate compound FMEE; stir and mix at 600-800 r / min for 40-60 min to obtain polyurethane adhesive; (3) Place the 300×300mm alkali-free glass fiber woven fabric and auxiliary materials including release cloth, guide net, guide tube, glue inlet tube and vacuum film bag into an 80℃ electric constant temperature drying oven for 1 hour to remove moisture and then take it out. (4) After laying the reinforcing and auxiliary materials according to the vacuum injection molding process sequence, seal the vacuum film bag. When the vacuum degree reaches -0.095MPa, start injecting the pre-treated polyurethane adhesive. (5) After complete curing at room temperature, place it in an electric heating constant temperature drying oven at 80°C for 2 hours and then let it cool naturally before using a cutting machine to remove the burrs. The chain extender A mentioned in step (1) is prepared by mixing 2,2-dihydroxymethylbutyric acid and N-methylpyrrolidone in a volume ratio of 1:3-1:5; The ultraviolet absorber mentioned in step (1) is any one of Sumisorb 110, Sumisorb 130, Sumisorb 140, Sumisorb 220, Sumisorb 250, and Sumisorb 300; The antioxidant mentioned in step (1) is any one of Irganox1010, Irganox1035, Irganox1076, and Irganox1222.

2. The method for preparing a polyurethane composite material according to claim 1, characterized in that, The catalyst in step (1) is dibutyltin dilaurate.

3. The method for preparing a polyurethane composite material according to claim 1, characterized in that, The chain extender B mentioned in step (1) is 1,4-butanediol.

4. The method for preparing a polyurethane composite material according to claim 1, characterized in that, The chain extender C mentioned in step (1) is 1,3-dihydroxymethylurea.

5. The method for preparing a polyurethane composite material according to claim 1, characterized in that, The chain extender D mentioned in step (1) is an aminopropyl-terminated polydimethylsiloxane.

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