Unsaturated waterborne polyurethane, polyurethane composite material and preparation method and application thereof

Abstract

The invention provides unsaturated waterborne polyurethane, a polyurethane composite material as well as a preparation method and application of the unsaturated waterborne polyurethane and the polyurethane composite material. According to the preparation method, isocyanate is introduced into a soft segment through a block process, an unsaturated chain extender is added, unsaturated double bonds are introduced, and waterborne polyurethane with excellent performance is prepared. Meanwhile, cellulose nanofibers are added into the unsaturated waterborne polyurethane, so that the interfacial compatibility and mechanical properties of the unsaturated waterborne polyurethane are improved. The unsaturated waterborne polyurethane provided by the invention has excellent film-forming property, stability and mechanical property.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials technology, specifically relating to an unsaturated waterborne polyurethane, polyurethane composite materials, their preparation methods, and applications. Background Technology

[0002] Waterborne polyurethane (WPU), as an environmental pioneer, uses water instead of organic solvents as a dispersion medium. Its dispersions contain little or no solvent, resulting in novel polyurethane emulsions with diameters ranging from nanometers to several micrometers. As a green and environmentally friendly material with high adhesion and good film-forming properties, waterborne polyurethane is widely used in all aspects of modern life and industry. Most products require excellent dimensional stability, durability, and mechanical properties. Therefore, it is particularly important to mechanically reinforce waterborne polyurethane from various angles during the preparation process to provide a high-performance waterborne polyurethane composite material.

[0003] Polymer materials are often damaged during storage, transportation and sales, which affects their mechanical properties and product value. Self-healing materials can automatically diagnose and repair damage, extend service life and improve the stability and reliability of material use.

[0004] However, the reinforcing effect of fibers largely depends on the interfacial interaction between the rubber matrix and the fibers. Reinforcement can only be achieved when there is effective stress transfer between the rubber and the fibers. Therefore, interfacial bonding strength plays a crucial role in the overall performance of rubber products. Due to the presence of hydrophilic groups in waterborne polyurethane molecules and defects in the resin itself, its interfacial bonding strength is limited to some extent. Many chemists have devoted themselves to modifying it to improve its performance. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention uses unsaturated chain extenders and hydrophilic chain extenders together to prepare an unsaturated waterborne polyurethane, and improves its interfacial compatibility and mechanical properties through block processing, adding fillers, co-vulcanization and other methods.

[0006] One of the objectives of this invention is to provide an unsaturated waterborne polyurethane comprising: soft segments derived from macromolecular polyols and isocyanate compounds (Ⅰ), and hard segments from isocyanate compounds (Ⅱ) and chain extenders, wherein the chain extenders contain hydrophilic groups and unsaturated groups.

[0007] In the unsaturated waterborne polyurethane provided by this invention:

[0008] The chain extender comprises a hydrophilic chain extender and an unsaturated chain extender. The hydrophilic chain extender is selected from at least one of dimethylolpropionic acid (DMPA), dimethylolbutyric acid (DMBA), tartaric acid, citric acid, dicarboxylic acid half-ester, sodium ethylenediaminoethanesulfonate amino acid, 2,5-dihydroxybenzoic acid, sodium 2-sulfonate-1,4-butanediol, methyl diethanolamine, N-methyldiethanolamine (MDEA), triethylenediamine (DTA), triethylenetetramine (TETA), bis-2-hydroxyethylbenzylamine, bis-2-hydroxypropylbenzylamine, and sodium ethylenediaminoethanesulfonate, preferably at least one of dimethylolpropionic acid (DMPA) and dimethylolbutyric acid (DMBA). The unsaturated chain extender is selected from glyceryl allyl ether (APD), trimethylolpropane monoallyl ether (TME), allyloxypropylene glycol, N-benzyl-2-pyrrolidone, etc. At least one of 1,5-hexadien-3,4-diol, glycerol monomethacrylate, butenyl glycol, 2,5-furandiethanol, glycerol 1,3-diglyceryl alcohol diacrylate, 5-norbornene-2,2-diethanol, 5-norbornene-2,3-diethanol, norbornene-2,3-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, N,N'-diallyl-L-tartrate, itaconic acid, ethylene guanidine, N,N'-(1,2-dihydroxyethylene)diacrylamide, N-hydroxymethylacrylamide, N-(2-hydroxymethyl)-2-methyl-2-acrylamide, N-(2-hydroxyethyl)-10-undecenamide, fumarate, and N-tris(hydroxymethyl)methacrylamide, preferably at least one of glycerol allyl ether (APD), trimethylolpropane monoallyl ether (TME), allyloxypropylene glycol, and butenyl glycol.

[0009] In the unsaturated waterborne polyurethane provided by this invention:

[0010] The macromolecular polyol is selected from at least one of polyether glycol and polyester glycol, preferably from at least one of polytetramethylene ether glycol (PTMG), polyethylene glycol (PEG), polypropylene glycol (PPG), polycaprolactone polyol (PCL), polybutylene adipate diol (PBA), and polycarbonate diol (PCDL).

[0011] The number average molecular weight of the macromolecular polyol is 400-4000, preferably 1000-3000;

[0012] The isocyanate compound (Ⅰ) in the soft segment and the isocyanate compound (Ⅱ) in the hard segment may be the same or different, and are independently selected from at least one of aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates, preferably from at least one of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), tetramethyl isophthalamide diisocyanate (TMXDI), terephthalamide diisocyanate (PPDI), isophthalamide diisocyanate (XDI), isophorone diisocyanate (IPDI), 1,5-naphthalene diisocyanate (NDI), L-lysine diisocyanate (LDI), dicyclohexylmethane diisocyanate (HXDI), hexamethylene diisocyanate (HDI), and pentamethylene diisocyanate (PDI).

[0013] A second objective of this invention is to provide a method for preparing the aforementioned unsaturated waterborne polyurethane, comprising: reacting a macromolecular polyol with an isocyanate compound (Ⅰ), then adding an isocyanate compound (Ⅱ) and a chain extender to continue the reaction, and finally neutralizing to obtain the unsaturated waterborne polyurethane. Specifically, the method for preparing the unsaturated waterborne polyurethane includes:

[0014] (1) The macromolecular polyol and isocyanate compound (Ⅰ) are reacted in the first step;

[0015] (2) Add isocyanate compound (II), hydrophilic chain extender and catalyst to carry out the second step reaction;

[0016] (3) Add an unsaturated chain extender to carry out the third step reaction to obtain polyurethane prepolymer;

[0017] (4) Add a neutralizing agent to carry out a neutralization reaction to obtain the unsaturated waterborne polyurethane.

[0018] In the preparation method of unsaturated waterborne polyurethane provided by this invention:

[0019] Based on 100 parts by weight of the macromolecular polyol, the isocyanate compound (Ⅰ) comprises 5-20 parts, the isocyanate compound (Ⅱ) comprises 20-80 parts, the hydrophilic chain extender comprises 3-15 parts, the unsaturated chain extender comprises 0.5-18 parts, the catalyst comprises 0.1-0.3 parts, and the neutralizing agent comprises 1-10 parts; preferably, based on 100 parts by weight of the macromolecular diol, the isocyanate compound (Ⅰ) comprises 8-15 parts, the isocyanate compound (Ⅱ) comprises 30-75 parts, the hydrophilic chain extender comprises 4-14 parts, the unsaturated chain extender comprises 1-15 parts, the catalyst comprises 0.1-0.2 parts, and the neutralizing agent comprises 2-8 parts.

[0020] The catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, and triethylenediamine;

[0021] The neutralizing agent is selected from at least one of trimethylamine, triethylamine, tripropylamine, dimethylcyclohexylamine, triethanolamine, N-methyldiethanolamine, ammonia, sodium bicarbonate, sodium carbonate, acetic acid, oxalic acid, glycolic acid, and chloromethylbenzene.

[0022] In the preparation method of unsaturated waterborne polyurethane provided by this invention:

[0023] The conditions for the first step of the reaction in step 1) are: 70-90℃ for 1-2 hours;

[0024] The conditions for the second step of the reaction in step 2) are: 70-90℃ for 1-4 hours;

[0025] The conditions for the third reaction in step 3) are: 70-90℃ for 1-3 hours;

[0026] The conditions for the neutralization reaction in step 4) are: 40-60℃ for 0.5-2 hours.

[0027] A third objective of this invention is to provide a polyurethane composite material comprising unsaturated aqueous polyurethane and cellulose nanofibers, wherein the unsaturated aqueous polyurethane is the aforementioned unsaturated aqueous polyurethane. Specifically, based on 100 parts by weight of the unsaturated aqueous polyurethane, the cellulose nanofibers comprise 0.05 to 2 parts, preferably 0.1 to 1.5 parts.

[0028] The fourth objective of this invention is to provide a method for preparing the above-mentioned polyurethane composite material, comprising: dispersing the unsaturated aqueous polyurethane in water and stirring to emulsify it; then adding cellulose nanofibers and stirring to obtain a composite material emulsion; and drying to obtain the polyurethane composite material. The ratio of the unsaturated aqueous polyurethane to water is 1:(2-4), the stirring and emulsification conditions are 900-2000 r / min, and the drying conditions are 20-60℃. The obtained composite material emulsion can optionally be poured into a mold to form a film, and after drying, a polyurethane composite film can be obtained.

[0029] The fifth objective of this invention is to provide the above-mentioned unsaturated waterborne polyurethane or polyurethane composite material for co-curing with optional auxiliary materials to prepare polyurethane rubber. The auxiliary materials can be commonly used in the art, added in the usual amounts. For example, the auxiliary materials include three types of vulcanizing agents: isocyanates, peroxides, and sulfur. Commonly used isocyanates include toluene diisocyanate (TDI) and its dimer, diphenylmethane diisocyanate (MDI) dimer, and polyphenylmethylene polyisocyanate (PAPI). Dicumyl peroxide (DCP) is preferred among the peroxide vulcanizing agents; other varieties include tert-butyl peroxide, benzoyl peroxide, dialkyl peroxide, alkyl peroxide, aralkyl peroxide, and diaralkyl peroxide. Based on 100 parts of the unsaturated waterborne polyurethane or polyurethane composite material, the amount of auxiliary material is 0.5 to 3.0 parts.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. This invention uses an unsaturated chain extender to synthesize a novel unsaturated waterborne polyurethane. The prepared waterborne polyurethane has excellent film-forming properties, stability, and mechanical properties.

[0032] 2. This invention introduces a portion of isocyanate into the soft segment and pre-regulates the block sequence of the macromolecular polyol, resulting in a more uniform distribution of soft and hard segments, more thorough mixing, increased ordered hydrogen bond interactions between soft and hard segments, improved microphase separation, and further enhanced mechanical properties.

[0033] 3. This invention adds bio-based cellulose nanofiber filler to prepare composite materials. Due to the introduction of double bonds on the side chains of waterborne polyurethane by the unsaturated chain extender, the composite material still contains unsaturated double bonds. Through these unsaturated double bonds, co-vulcanization is achieved, the effective stress transfer between the fiber and the rubber matrix is ​​increased, the interfacial compatibility is improved, and it is better matched with the filler, thereby improving the interfacial adhesion strength and increasing the mechanical strength by 30%.

[0034] 4. This invention can be obtained by blending other materials, such as polymers or processing aids, with the unsaturated waterborne polyurethane or polyurethane composite material described herein using conventional rubber processing methods. The process is simple, reproducible, and environmentally friendly, making it suitable for industrial production. Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0036] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0037] Example 1

[0038] Preparation of polytrimethylene ether glycol type unsaturated waterborne polyurethane:

[0039] Step 1: Add 30.00 g of polytrimethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 110°C for 2 hours;

[0040] Step 2: Cool down to 75℃, and add 2.67g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min;

[0041] Step 3: Add 10.68g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 2.40g of DMBA to a three-necked flask. Maintain the temperature at 80℃ and react for 1.5 hours.

[0042] Step 4: Add 1.05g of TME to the three-necked flask, maintain the temperature at 80℃, and react for 1 hour;

[0043] Step 5: Add 1.65g of triethylamine as a neutralizing agent to a three-necked flask to neutralize and form a salt. Control the temperature at 50℃ and react for 1 hour to obtain polytrimethylene ether glycol type unsaturated waterborne polyurethane.

[0044] Preparation of polyurethane composite materials:

[0045] 112.89 g of deionized water was added to the three-necked flask used to prepare polytrimethylene ether glycol-type unsaturated waterborne polyurethane, and emulsified at high speed (900 r / min) for 0.5 h. Then, 0.15 g of cellulose nanofiber filler (CNFs) was added, and the mixture was stirred at high speed at 2000 rpm for 0.5 h. After stirring was stopped and the mixture was allowed to stand, the composite material was poured out of the three-necked flask to obtain a composite material emulsion. The composite material emulsion was poured into a polytetrafluoroethylene mold and left at room temperature for 2 days to form a film. The film was then placed in a 60°C oven until it reached constant weight, and then removed and cooled to room temperature to obtain a polyurethane composite film.

[0046] Example 2

[0047] Preparation of polytrimethylene ether glycol type unsaturated waterborne polyurethane:

[0048] Step 1: Add 30.00 g of polytrimethylene ether glycol (number average molecular weight 1000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0049] Step 2: Cool down to 75℃, and add 2.70g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min;

[0050] Step 3: Add 10.80g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 3.30g of DMBA to a three-necked flask. Control the temperature at 80℃ and react for 1.5h.

[0051] Step 4: Add 3.6g of APD to the three-necked flask, maintain the temperature at 80℃, and react for 1 hour;

[0052] Step 5: Add 2.25g of acetic acid as a neutralizing agent to a three-necked flask to neutralize and form a salt. Control the temperature at 50℃ and react for 1 hour to obtain polytrimethylene ether glycol type unsaturated waterborne polyurethane.

[0053] Preparation of polyurethane composite materials:

[0054] 122.67 g of deionized water was added to the three-necked flask used to prepare polytrimethylene ether glycol type unsaturated waterborne polyurethane and emulsified at high speed (2000 r / min) for 1.5 h. Then, polyurethane composite film was prepared according to the preparation method of Example 1.

[0055] Example 3

[0056] Preparation of polytrimethylene ether glycol type unsaturated waterborne polyurethane:

[0057] Step 1: Add 30.00 g of polytrimethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 130°C for 2 hours;

[0058] Step 2: Cool down to 75℃, and add 2.88g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min;

[0059] Step 3: Add 11.52g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 2.40g of DMBA to a three-necked flask. Control the temperature at 80℃ and react for 1.5h.

[0060] Step 4: Add 0.51g of TME to the three-necked flask, maintain the temperature at 80℃, and react for 1 hour;

[0061] Step 5: Add 1.65g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 40℃ and react for 0.5h to obtain polytrimethylene ether glycol type unsaturated waterborne polyurethane.

[0062] Preparation of polyurethane composite materials:

[0063] 114.08 g of deionized water was added to the three-necked flask used to prepare polytrimethylene ether glycol type unsaturated waterborne polyurethane and emulsified at high speed (1200 r / min) for 0.5 h. Then, polyurethane composite film was prepared according to the preparation method of Example 1.

[0064] Example 4

[0065] Preparation of polytetramethylene ether glycol type unsaturated waterborne polyurethane:

[0066] Step 1: Add 30g of polytetramethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120℃ for 2.5h;

[0067] Step 2: Cool down to 75℃, and add 2.70g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min;

[0068] Step 3: Add 10.80g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 2.40g of DMBA to a three-necked flask. Control the temperature at 80℃ and react for 3 hours.

[0069] Step 4: Add 0.60 g of APD to the three-necked flask, maintain the temperature at 80 °C, and react for 1 hour;

[0070] Step 5: Add 1.65g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 50℃ and react for 2 hours to obtain polytetramethylene ether glycol type unsaturated waterborne polyurethane.

[0071] Preparation of polyurethane composite materials:

[0072] 112.19 g of deionized water was added to the three-necked flask used to prepare polytetramethylene ether glycol type unsaturated waterborne polyurethane and emulsified at high speed (1800 r / min) for 0.5 h. Then, polyurethane composite film was prepared according to the preparation method of Example 1.

[0073] Example 5

[0074] Preparation of polytetramethylene ether glycol type unsaturated waterborne polyurethane:

[0075] Step 1: Add 30.00 g of polytetramethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0076] Step 2: Cool to 75℃, and add 2.70g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min.

[0077] Step 3: Add 10.80g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 1.41g of DMBA to a three-necked flask. Control the temperature at 80℃ and react for 1.5h.

[0078] Step 4: Add 1.41 g of APD to the three-necked flask, maintain the temperature at 80°C, and react for 3 hours;

[0079] Step 5: Add 0.96g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 40℃ and react for 1 hour to obtain polytetramethylene ether glycol type unsaturated waterborne polyurethane.

[0080] Preparation of polyurethane composite materials:

[0081] 110.16 g of deionized water was added to the three-necked flask used to prepare polytetramethylene ether glycol type unsaturated waterborne polyurethane and emulsified at high speed (2000 r / min) for 0.5 h. Then, polyurethane composite film was prepared according to the preparation method of Example 1.

[0082] Example 6

[0083] Preparation of polytetramethylene ether glycol type unsaturated waterborne polyurethane:

[0084] Step 1: Add 30.00 g of polytetramethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0085] Step 2: Cool down to 75℃, and add 2.70g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min;

[0086] Step 3: Add 10.80g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 1.41g of DMBA to a three-necked flask. Control the temperature at 80℃ and react for 1.5h.

[0087] Step 4: Add 1.41 g of APD to the three-necked flask, maintain the temperature at 80°C, and react for 3 hours;

[0088] Step 5: Add 0.96g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 40℃ and react for 1 hour to obtain polytetramethylene ether glycol type unsaturated waterborne polyurethane.

[0089] Preparation of polyurethane composite materials:

[0090] 110.16 g of deionized water was added to the three-necked flask used to prepare polytetramethylene ether glycol-type unsaturated waterborne polyurethane, and emulsified at high speed (2000 r / min) for 0.5 h. Then, 0.30 g of cellulose nanofiber filler (CNFs) was added, and the mixture was stirred at high speed at 2000 rpm for 0.5 h. After stirring was stopped and the mixture was allowed to stand, the composite material was poured out of the three-necked flask to obtain a composite material emulsion. The composite material emulsion was poured into a polytetrafluoroethylene mold and left at room temperature for 2 days to form a film. The film was then placed in a 60°C oven until it reached constant weight, and then removed and cooled to room temperature to obtain a polyurethane composite film.

[0091] Comparative Example 1

[0092] Preparation of waterborne polyurethane of the polytrimethylene ether glycol type:

[0093] Step 1: Add 30.00 g of polytrimethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0094] Step 2: Cool down to 75℃, and add 2.67g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min;

[0095] Step 3: Add 10.68g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 1.41g of DMBA to a three-necked flask, and control the temperature at 80℃ for 3 hours.

[0096] Step 4: Add 1.38g of TME to the three-necked flask, maintain the temperature at 80℃, and react for 1.5h;

[0097] Step 5: Add 0.96g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 45℃ and react for 1 hour to obtain polytrimethylene ether glycol type waterborne polyurethane.

[0098] Preparation of polyurethane composite materials:

[0099] Add 109.74 g of deionized water to the three-necked flask used to prepare polytrimethylene ether glycol-type waterborne polyurethane, emulsify at high speed (2000 r / min) for 1 h, then pour into a polytetrafluoroethylene mold, let it stand at room temperature for 2 days to form a film, then put it in a 60℃ oven, and after it reaches constant weight, take it out and cool it to room temperature to obtain the waterborne polyurethane composite film.

[0100] Comparative Example 2

[0101] Preparation of polytetramethylene ether glycol-based waterborne polyurethane:

[0102] Step 1: Add 30.00 g of polytetramethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0103] Step 2: Cool to 65℃, and add 2.67g of isoflurane diisocyanate, which is used in the preparation of the soft segment, while stirring at 200r / min.

[0104] Step 3: Add 10.68g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 1.38g of DMBA to a three-necked flask. Maintain the temperature at 75℃ and react for 3 hours.

[0105] Step 4: Add 0.99 g of APD to the three-necked flask, maintain the temperature at 80°C, and react for 2 hours;

[0106] Step 5: Add 0.96g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 50℃ and react for 1 hour to obtain polytetramethylene ether glycol type waterborne polyurethane.

[0107] Preparation of polyurethane composite materials:

[0108] 108.76 g of deionized water was added to the three-necked flask used to prepare polytetramethylene ether glycol-type waterborne polyurethane, and emulsified at high speed (2000 r / min) for 0.5 h. Then, polyurethane composite film was prepared according to the preparation method of Comparative Example 1.

[0109] Comparative Example 3

[0110] Preparation of waterborne polyurethane of the polytrimethylene ether glycol type:

[0111] Step 1: Add 30.00 g of polytrimethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0112] Step 2: Cool down to 75℃, add 13.35g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 1.41g of DMBA while stirring at 200r / min. Control the temperature at 80℃ and react for 3h.

[0113] Step 3: Add 1.38g of TME to the three-necked flask, maintain the temperature at 80℃, and react for 1.5h;

[0114] Step 4: Add 0.96g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 45℃ and react for 1 hour to obtain polytrimethylene ether glycol type waterborne polyurethane.

[0115] Preparation of polyurethane composite materials:

[0116] Add 109.74 g of deionized water to the three-necked flask used to prepare polytrimethylene ether glycol-type waterborne polyurethane, emulsify at high speed (2000 r / min) for 1 h, then pour into a polytetrafluoroethylene mold, let it stand at room temperature for 2 days to form a film, then put it in a 60℃ oven, and after it reaches constant weight, take it out and cool it to room temperature to obtain the waterborne polyurethane composite film.

[0117] Comparative Example 4

[0118] Preparation of polytetramethylene ether glycol-based waterborne polyurethane:

[0119] Step 1: Add 30.00 g of polytetramethylene ether glycol (number average molecular weight 2000) to a three-necked flask and dehydrate under vacuum at 120°C for 2 hours;

[0120] Step 2: Cool down to 65℃, add 13.35g of isoflurane diisocyanate, 1-2 drops of dibutyltin dilaurate, and 1.38g of DMBA while stirring at 200r / min. Control the temperature at 75℃ and react for 3h.

[0121] Step 3: Add 0.99g of APD to the three-necked flask, maintain the temperature at 80℃, and react for 2 hours;

[0122] Step 4: Add 0.96g of neutralizing agent TEA to a three-necked flask to neutralize and form a salt. Control the temperature at 50℃ and react for 1 hour to obtain polytetramethylene ether glycol type waterborne polyurethane.

[0123] Preparation of polyurethane composite materials:

[0124] 108.76 g of deionized water and 0.15 g of cellulose nanofiber filler (CNFs) were added to the three-necked flask used to prepare polytetramethylene ether glycol-type waterborne polyurethane. The mixture was emulsified at high speed (2000 r / min) for 0.5 h. Then, the polyurethane composite film was prepared according to the preparation method of Comparative Example 1.

[0125] Test case

[0126] The performance of the waterborne polyurethane samples from Examples 1-6 and Comparative Examples 1-4 was tested using the following methods:

[0127] Mechanical property testing: Tensile testing was conducted according to GB / T 528-2009. The tensile rate was 500 mm / min, and the specimen size was 25 mm × 4 mm × 1 mm.

[0128] The mechanical property test results are shown in Table 1.

[0129] Table 1. Tensile strength and elongation at break of different sample films

[0130] sample Tensile strength / MPa Elongation at break / % Example 1 15.6 491 Example 2 16.7 483 Example 3 21.1 381 Example 4 17.4 436 Example 5 22.2 429 Example 6 23.6 433 Comparative Example 1 12.7 362 Comparative Example 2 13.6 351 Comparative Example 3 9.4 350 Comparative Example 4 11.1 342

[0131] As can be seen from the data in Table 1, the tensile strength and elongation at break of the polyurethanes in Examples 1-6 are significantly higher than those in Comparative Examples 1-4. In this invention, isocyanate is first used to prepare block-modified macromolecular diols, which can effectively improve the degree of microphase separation between soft and hard segments, thereby improving the mechanical properties of the polyurethane material. The mechanical tests in Table 1 also show that the mechanical strength of the polyurethane materials obtained in Examples 1-6 is increased by as much as 30%. Furthermore, Examples 1-3 show that for the same polyol, the tensile strength tends to increase with the increase of isocyanate content in the soft segment. Comparison of Examples 5-6 shows that the tensile strength and elongation at break of the composite material can be effectively improved with the increase of cellulose content. It can also be seen that adjusting variables such as the molecular weight of the soft segment, the isocyanate index R value (the molar ratio of benzocyanate groups (-NCO) to hydroxyl groups (-OH), the content of the hydrophilic chain extender, and the type of isocyanate can control the tensile strength and elongation at break. The performance comparison between the examples and comparative examples demonstrates that this invention can improve the mechanical properties of waterborne polyurethanes through block processing and modification with the addition of cellulose fillers.

[0132] Preparation of H-samples: Based on 100 parts by weight of polyurethane composite material, add 0.5 parts stearic acid, 1 part activator, 2 parts accelerator DM, 1 part accelerator D, and 1 part sulfur. Mix the polyurethane composite film with the weighed ingredients on a two-roll mill, cutting and turning it from side to side, forming a thin triangular bundle, adjusting the roll gap to ensure uniform mixing in the two-roll mill, cooling, and allowing it to stand to obtain the standard adhesive.

[0133] The prepared standard rubber was extruded into 5mm thick rubber sheets on a two-roll mill, and then cut into 10mm wide strips. The cut rubber strips were pressed into the cavity of an H-shaped extraction and vulcanization mold, and impregnated nylon 66 cord was embedded into the rubber. The other end of the cord was stretched and fixed with a 50g weight. The upper and lower parts of the mold were then closed and secured with locating pins. Finally, the H-shaped extraction mold was placed in a flat vulcanizing machine for vulcanization. The vulcanization conditions for the PA66 cord were 3.5MPa, 136℃ × 50min. After vulcanization, the samples were cut into H-shaped strips and left to stand for at least 8 hours before adhesive performance testing.

[0134] Preparation of 180° peel samples: Based on 100 parts by weight of polyurethane composite material, add 0.5 parts stearic acid, 1 part activator, 2 parts accelerator DM, 1 part accelerator D, and 1 part sulfur. Mix the polyurethane composite film with the weighed ingredients on a two-roll mill, cutting and turning it from side to side, forming thin triangular bundles, adjusting the roll gap to ensure uniform mixing in the two-roll mill, cooling, and allowing it to stand to obtain the standard adhesive.

[0135] The refined standard rubber was pressed into a rubber sheet approximately 1.7 mm thick and cut into 235 mm × 160 mm pieces. A 0.5 mm × 25 mm × 160 mm rubber sheet was then prepared and placed on top of the mold. One end of the impregnated rubber cord was fixed in a groove at the top of the mold and tensioned. The cord was then repeatedly arranged between the grooves at both ends of the mold, with 5 cords arranged for each sample. Finally, a 300 g weight was hung at the end of the cord. Next, a piece of cellophane slightly larger than the 25 mm wide rubber sheet was placed above the cord. The 1.7 mm × 235 mm × 160 mm rubber sheet was then placed on top of the cellophane and cord, and a piece of fabric of similar size to the rubber sheet was placed on top as a reinforcing layer. After closing the mold, the sample was vulcanized at 3.5 MPa pressure and 160 °C for 20 minutes. After vulcanization, the sample was cut into strips of 25mm × 235mm. The sample was left to stand for 16 hours before the adhesion performance was tested.

[0136] Static adhesion performance test: The H-pull-out force test followed standard GB / T2943-2009, with a tensile speed of 100 mm / min. The sample was vulcanized and left to stand for 8 hours before testing. The 180° peel force test followed standard GB / T40725-2021, with a tensile speed of 300 mm / min. The sample was vulcanized and left to stand for 16 hours before testing. The results of the static adhesion performance tests are shown in Table 2.

[0137] Adhesive amount: The percentage (%) of the amount of adhesive solution adhering to the curtain fabric. The results are shown in Table 2.

[0138] Table 2. H-pulling force and 180° peel force for different samples

[0139] sample Adhesive content / % H extraction force / N 180° peel force (N / piece) Example 1 4.8 169.71 16.52 Example 2 4.7 174.62 17.19 Example 3 4.9 195.31 23.08 Example 4 4.7 186.95 19.34 Example 5 5.1 199.07 21.35 Example 6 5.1 207.53 26.71 Comparative Example 1 4.4 133.04 13.21 Comparative Example 2 4.2 141.59 14.73 Comparative Example 3 4.3 127.81 12.94 Comparative Example 4 4.2 130.52 11.57

[0140] As shown in Table 2, the polyurethane composite vulcanized samples prepared in Examples 1-6 all exhibited H-pull-out forces exceeding 160N and 180° peel forces exceeding 16N, representing an increase of over 40% in pull-out force. All these values ​​are significantly higher than those of the vulcanized samples in Comparative Examples 1-4. This invention introduces double bonds through an unsaturated chain extender, ensuring that the prepared composite material still contains unsaturated double bonds. This effectively achieves co-vulcanization, improves interfacial adhesion strength and compatibility, and simultaneously enhances the effectiveness of the modified filler CNFs. Using this method, the desired mechanical effects can be achieved with a smaller amount of modifying components.

Claims

1. An unsaturated aqueous polyurethane, comprising: A soft segment derived from a macromolecular polyol and an isocyanate compound (I), and a hard segment of an isocyanate compound (II) and a chain extender, wherein the chain extender contains a hydrophilic group and an unsaturated group.

2. The unsaturated waterborne polyurethane according to claim 1, wherein, The chain extender contains a hydrophilic chain extender and an unsaturated chain extender; The hydrophilic chain extender is at least one selected from dimethylolpropionic acid, dimethylolbutyric acid, tartaric acid, citric acid, dicarboxylic half ester, ethylenediamine sulfonic acid sodium amino acid, 2,5-dihydroxybenzoic acid, 2-sulfonic acid sodium-1,4-butanediol, methyldiethanolamine, N-methyldiethanolamine, triethylenediamine, triethylenetetramine, bis-2-hydroxyethyl benzylamine, bis-2-hydroxypropyl benzylamine, ethylenediamine sulfonic acid sodium, preferably at least one selected from dimethylolpropionic acid and dimethylolbutyric acid; and / or, The unsaturated chain extender is at least one selected from glyceryl allyl ether, trimethylolpropane monoallyl ether, allyloxypropanediol, N-benzyl-2-pyrrolidone, 1,5-hexadiene-3,4-diol, glycerol monomethacrylate, butenediol, 2,5-furandimethanol, glycerol 1,3-diglycerol diacrylate, 5-norbornene-2,2-dimethanol, 5-norbornene-2,3-dimethanol, norbornene-2,3-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, N,N'-diallyl-L-tartaric amide, itaconic acid, ethylene guanidine amine, N,N'-(1,2-dihydroxyethylene) dipropylene amide, N-hydroxymethyl acrylamide, N-(2-hydroxymethyl)-2-methyl-2-acrylamide, N-(2-hydroxyethyl)-10-undecenamide, fumaramide, N-trihydroxymethyl methacrylamide, preferably at least one selected from glyceryl allyl ether, trimethylolpropane monoallyl ether, allyloxypropanediol, butenediol.

3. The unsaturated waterborne polyurethane according to claim 1, wherein, The macromolecular polyol is at least one selected from polyether glycol, polyester glycol, preferably at least one selected from polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, polycaprolactone polyol, polybutylene adipate glycol, polycarbonate diol; and / or, The number average molecular weight of the macromolecular polyol is 400-4000, preferably 1000-3000; and / or, The isocyanate compound (I) in the soft segment and the isocyanate compound (II) in the hard segment are the same or different, and are independently at least one selected from aromatic isocyanate, alicyclic isocyanate, aliphatic isocyanate, preferably at least one selected from diphenylmethane diisocyanate, toluene diisocyanate, tetramethyl m-xylylene diisocyanate, p-phenylene diisocyanate, m-xylylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, L-lysine diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate.

4. A process for the preparation of the unsaturated aqueous polyurethane according to any one of claims 1 to 3, comprising: The unsaturated waterborne polyurethane is prepared by reacting a macromolecular polyol with an isocyanate compound (I), adding an isocyanate compound (II) and a chain extender, and then neutralizing the product.

5. The preparation method according to claim 4, characterized in that, The preparation method of the unsaturated waterborne polyurethane comprises the following steps: (1) a first step reaction of a macromolecular polyol and an isocyanate compound (I); (2) a second step reaction of an isocyanate compound (II), a hydrophilic chain extender and a catalyst; (3) a third step reaction of an unsaturated chain extender to obtain a polyurethane prepolymer; (4) a neutralization reaction of a neutralizing agent to obtain the unsaturated waterborne polyurethane.

6. The preparation method according to claim 5, wherein, based on 100 parts by weight of the macromolecular polyol, the isocyanate compound (I) is 5-20 parts, the isocyanate compound (II) is 20-80 parts, the hydrophilic chain extender is 3-15 parts, the unsaturated chain extender is 0.5-18 parts, the catalyst is 0.1-0.3 parts, and the neutralizing agent is 1-10 parts; preferably, based on 100 parts by weight of the macromolecular polyol, the isocyanate compound (I) is 8-15 parts, the isocyanate compound (II) is 30-75 parts, the hydrophilic chain extender is 4-14 parts, the unsaturated chain extender is 1-15 parts, the catalyst is 0.1-0.2 parts, and the neutralizing agent is 2-8 parts; and / or, the catalyst is at least one selected from dibutyltin dilaurate, stannous octoate and triethylenediamine; and / or, the neutralizing agent is at least one selected from trimethylamine, triethylamine, tripropylamine, dimethylcyclohexylamine, triethanolamine, N-methyldiethanolamine, ammonia, sodium bicarbonate, sodium carbonate, acetic acid, oxalic acid, glycolic acid and chloromethylbenzene.

7. The preparation method according to claim 5, wherein, the first step reaction in step 1) is carried out at 70-90°C for 1-2 hours; and / or, the second step reaction in step 2) is carried out at 70-90°C for 1-4 hours; and / or, the third step reaction in step 3) is carried out at 70-90°C for 1-3 hours; and / or, the neutralization reaction in step 4) is carried out at 40-60°C for 0.5-2 hours.

8. A polyurethane composite material comprising an unsaturated waterborne polyurethane and cellulose nanofiber, wherein the unsaturated waterborne polyurethane is the unsaturated waterborne polyurethane according to any one of claims 1-3 or obtained by the preparation method according to any one of claims 4-7, and preferably, based on 100 parts by weight of the unsaturated waterborne polyurethane, the cellulose nanofiber is 0.05-2 parts. The unsaturated waterborne polyurethane is dispersed in water and emulsified by stirring, and then the cellulose nanofiber is added and stirred to obtain a composite material emulsion, which is dried to obtain the polyurethane composite material. ​ ​ ​ ​ ​ ​ 9. A method of making the polyurethane composite of claim 8, comprising: ​ 10. Unsaturated aqueous polyurethane according to any one of claims 1 to 3 or polyurethane composite according to claim 8 for the production of polyurethane rubber by co-vulcanization with optional auxiliary materials.