Polyurethane resin material

Abstract

The invention discloses a polyurethane resin material, and belongs to the technical field of polyurethane resin. The polyurethane resin material is prepared from the following components in parts by weight: 40 to 80 parts of bio-based polycarbonate diol; 20 to 60 parts of bio-based diisocyanate; 5-25 parts of a chain extender and a cross-linking agent; 0.01 to 1 part of a catalyst; 0.2 to 1 part of a heat stabilizer; 0.2 to 1.5 parts of an antioxidant composition; 1-5 parts of a toughening agent; 0.3-1 part of a lubricating flowable agent; and 0.1-0.5 part of an ultraviolet light absorber. The polyurethane material disclosed by the invention has excellent thermal stability and mechanical properties, and the thermal stability and chemical inertness of a molecular chain are enhanced by introducing a flexible chain segment of a carbonate structure and a main chain structure constructed by bio-based aliphatic diisocyanate, so that the prepared polyurethane material is not easy to degrade in a heat treatment or use process. The material has excellent ultraviolet aging resistance, and the photo-thermal stability of the material under ultraviolet radiation is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane resins, and more particularly to a polyurethane resin material. Background Art

[0002] Polyurethane materials, due to their excellent mechanical properties, flexibility, and chemical resistance, are widely used in coatings, adhesives, elastomers, foams, synthetic leather, and other fields. Traditional polyurethanes are primarily produced by reacting petrochemical-derived polyether or polyester polyols with isocyanates. Their production relies on non-renewable petroleum resources and can release toxic byproducts during synthesis and use, posing certain environmental risks.

[0003] In recent years, with the advancement of the concept of sustainable development and the implementation of the country's "dual carbon" policy, the demand for high-performance, bio-based and degradable polymer materials has been increasing. As a new type of green material, bio-based polyurethane has attracted the attention of more and more researchers. Bio-based polyurethane refers to polyurethane materials synthesized through green chemical routes using biomass resources (such as vegetable oils, sugars, carbon dioxide, natural amino acids, etc.) as raw materials. They have good environmental friendliness and controllable structural properties. Among them, polycarbonate diol (PCCD) copolymerized with carbon dioxide and epoxide is used as the raw material for the soft segment of polyurethane. It can not only achieve the effective utilization of carbon resources, but also introduce carbonate bonds into the molecular chain, thereby significantly improving the heat resistance, transparency and thermal stability of the material.

[0004] Currently, research on polycarbonate-based polyurethanes (PCPUs) focuses primarily on copolymerization and modification based on polyether or polyester polyols, or on the addition of functional additives to enhance their performance. However, the following challenges remain: On the one hand, some existing bio-based polyurethanes have poor mechanical properties, failing to meet the demands of high-strength and impact-resistant applications; on the other hand, their heat resistance, UV aging resistance, and hydrolytic stability still need to be improved, limiting their widespread application in areas such as engineering plastics and functional coatings. Furthermore, while aromatic diisocyanates (such as MDI and TDI) commonly used in traditional polyurethanes are highly reactive, their preparation and use processes can easily release hazardous substances, which are detrimental to the ecological environment and human health.

[0005] Therefore, the development of a new polyurethane material based on bio-based polycarbonate diol, combined with aliphatic bio-based isocyanates, green chain extenders, and functional stabilizers, has important research value and broad application prospects. By introducing carbonate structures and all-biobased monomers and optimizing their thermal stability and mechanical properties at the molecular level, the green and sustainable nature of the material can be achieved, while meeting the multiple requirements of strength, flexibility, weather resistance, and environmental friendliness in engineering applications. Summary of the Invention

[0006] The object of the present invention is to provide a polyurethane resin material to solve the problems raised by the above background technology.

[0007] A polyurethane resin material comprises the following components in parts by weight:

[0008] 40-80 parts of bio-based polycarbonate diol, with a molecular weight of 500-3000 g / mol and a linear structure containing carbonate bonds in the main chain;

[0009] 20-60 parts of bio-based diisocyanate, selected from one or more of lysine diisocyanate, castor oil-based isocyanate or linoleic acid-based isocyanate;

[0010] 5 to 25 parts of a chain extender and a cross-linking agent, wherein the chain extender is selected from one or more of 1,4-butanediol and isosorbide, and the cross-linking agent is selected from one or more of trimethylolpropane and glycerol;

[0011] 0.01-1 part of catalyst, selected from one of organic tin, bismuth or amine catalysts;

[0012] 0.2-1 part of heat stabilizer, selected from pentaerythritol phosphate, phosphite or hindered phenol compound;

[0013] 0.2 to 1.5 parts of an antioxidant composition, consisting of a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168;

[0014] 1 to 5 parts of a toughening agent, selected from one or more of polybutadiene rubber, hydroxyl-terminated nitrile rubber, and polyester elastomer;

[0015] 0.3-1 part of lubricating flow agent, selected from polyethylene wax, polypropylene wax or silicone flow agent;

[0016] 0.1 to 0.5 parts of ultraviolet absorber, selected from UV-531, UV-328 or TINUVINP.

[0017] Preferably, the bio-based polycarbonate diol is a polymer produced by copolymerization of carbon dioxide, propylene oxide and butylene oxide, and has a hydroxyl value of 30 to 70 mgKOH / g.

[0018] Preferably, the bio-based diisocyanate has an NCO functionality of 2 and an NCO mass content of 20% to 28%.

[0019] Preferably, the content of isosorbide in the chain extender is more than 60% of the total mass of the chain extender, and the mass ratio of trimethylolpropane to glycerol in the cross-linking agent is 2:1 to 4:1.

[0020] Preferably, the catalyst is dibutyltin dilaurate, and its usage is 0.05% to 0.3% of the total mass.

[0021] Preferably, the mass ratio of the primary antioxidant to the auxiliary antioxidant in the antioxidant composition is 1:2 to 1:3.

[0022] Preferably, the absorption peak of the ultraviolet absorber is within the range of 290 to 340 nm.

[0023] Preferably, the polyurethane material has the following properties after thermal curing: tensile strength of 20 to 50 MPa, elongation at break of 150% to 300%, glass transition temperature of -10°C to 40°C, and thermal decomposition temperature of not less than 220°C.

[0024] Preferably, the method for preparing the material comprises the following steps:

[0025] Step 1: mixing bio-based polycarbonate diol and bio-based diisocyanate in a set ratio, reacting at 70° C. to 90° C. under a nitrogen atmosphere for 1 to 2 hours to form an isocyanate-terminated prepolymer;

[0026] Step 2: adding a chain extender or a crosslinking agent, a catalyst, a heat stabilizer, an antioxidant, a toughening agent, a lubricant and an ultraviolet absorber to the obtained prepolymer in sequence, and stirring evenly at 80° C. to 100° C.;

[0027] Step 3: Inject the stirred system into a mold, cure at 90°C to 110°C for 30 to 60 minutes, demold, heat treat at 120°C to 140°C for 20 to 40 minutes, and cool to obtain the target material.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) The present invention is environmentally friendly and sustainable. The polycarbonate diol is a bio-based polyol produced by copolymerization of carbon dioxide and epoxide, significantly reducing dependence on petrochemical resources and improving carbon utilization in the material system. Furthermore, the selected isocyanate is derived from bio-based monomers such as lysine and does not release toxic aromatic amine degradation products during synthesis and use, effectively reducing environmental pollution and occupational health risks.

[0030] (2) The present invention has excellent thermal stability and mechanical properties. By introducing a flexible carbonate chain segment and a main chain structure constructed with a bio-based aliphatic diisocyanate, the thermal stability and chemical inertness of the molecular chain are enhanced, making the resulting polyurethane material less susceptible to degradation during heat treatment or use. The introduction of isosorbide as a chain extender in the composite system improves the material's crystallinity and chain segment regularity, thereby achieving a tensile strength of 30-50 MPa and an elongation at break exceeding 250%. It can be widely used in scenarios requiring both toughness and strength.

[0031] (3) The present invention has good hydrolysis resistance and chemical stability. The carbonate structure has stronger polarity and higher chemical stability than the traditional ester chain structure, and is not easily transesterified or hydrolyzed with water or polar solvents. This gives the present invention material excellent moisture and heat resistance, making it suitable for harsh environments such as high humidity and high temperature. Furthermore, the material exhibits strong dimensional stability and mechanical retention in acidic and alkaline media, making it suitable for applications in electrical appliances, coatings, medical devices, and other fields.

[0032] (4) The present invention exhibits excellent resistance to UV aging. The addition of a benzotriazole UV absorber, UV-531, in conjunction with a hindered amine light stabilizer effectively enhances the material's photothermal stability under UV irradiation, preventing performance degradation and discoloration due to molecular chain breakage. Long-term exposure tests show that the material retains over 90% of its tensile properties after 200 hours of UV irradiation, significantly outperforming conventional polyurethane materials without added light stabilizers.

[0033] (5) The present invention possesses excellent processing and molding properties and a controllable cross-linking structure. The introduction of multifunctional cross-linking agents such as trimethylolpropane into the material system enables the polyurethane to form a uniform three-dimensional network structure during the thermal curing process, thereby significantly improving the material's swelling resistance and dimensional stability. The use of organotin catalysts to regulate the reaction rate enables efficient polycondensation between the prepolymer and the chain extender, ensuring that there are no bubbles or precipitation during the product molding process. The product is suitable for various processing methods such as injection molding, hot pressing, coating, and 3D printing.

[0034] (6) The present invention has good compatibility and functional modification potential. The bio-based polycarbonate structure is rich in polar functional groups (hydroxyl groups, carbonate bonds, etc.), which can achieve interfacial coupling with a variety of functional fillers (such as nanocellulose, graphene oxide, etc.) to improve the overall performance of the composite material; at the same time, the structure can introduce functional monomers such as antibacterial, conductive, and flame retardant through end group or block grafting, and has high designability and application scalability. DETAILED DESCRIPTION

[0035] Example 1:

[0036] The following formula was weighed: 30 parts of a mixture of polycarbonate diol (PCC) and castor oil-based polyol (CO-POLYOL) in a mass ratio of 1:1, 20 parts of isocyanate MDI, 10 parts of chain extender 1,4-butanediol, 0.3 parts of catalyst tin octanoate, 0.1 parts of antifoaming agent silicone oil, 3 parts of cosolvent diethylene glycol, 0.5 parts of heat stabilizer antioxidant 1010, and 2 parts of flame retardant phosphorus flame retardant (such as tris (2-hydroxyethyl) phosphate). PCC and CO-POLYOL were stirred uniformly at 60°C to form a polyol component, and auxiliary agents, antioxidants and flame retardants were added in sequence. After continuing stirring for 20 minutes, MDI was slowly added dropwise to control the NCO / OH molar ratio to 1.05:1. The mixture was reacted at 75°C for 90 minutes to form a prepolymer. 1,4-Butanediol was then added as a chain extender to carry out a chain extension reaction. After the reaction lasted for 30 minutes, the mixture was poured into a preheated mold and cured at 90°C for 2 hours. The mixture was then cooled to room temperature and demolded to obtain a bio-based polycarbonate polyurethane resin sample A.

[0037] Example 2:

[0038] Weigh out according to the following ratio: 40 parts of PCC and citric acid modified soybean oil-based polyol (SO-POLYOL) blended in a mass ratio of 1.2:1, 25 parts of HDI (hexamethylene diisocyanate), 12 parts of 1,6-hexanediol, 0.4 parts of tin catalyst, 0.15 parts of polyether modified silicone oil as a foam suppressant, 0.5 parts of DLTP as an antioxidant, 0.2 parts of UV absorber UV-328, 3 parts of nitrogen-phosphorus composite flame retardant as a flame retardant, and 0.5 parts of polyethylene wax as a flow aid. PCC and SO-POLYOL were stirred and mixed at 70°C for 30 minutes, and then the additives and flame retardant were added. After reacting for 10 minutes, HDI was slowly added dropwise to the system, and the NCO / OH molar ratio was controlled to be 1.1:1. The reaction was carried out at 85°C for 100 minutes. Subsequently, the chain extender 1,6-hexanediol was added and the reaction was continued for 40 minutes. Finally, the mixture was injected into a flat mold, cured at 95°C for 3 hours, and cooled and demolded to produce resin sample B with high flexibility and flame retardant properties.

[0039] Example 3:

[0040] Weigh 35 parts of PCC and polylactic acid copolyol (PLA-POLYOL) in a mass ratio of 1:0.8, 18 parts of TDI (diphenylmethane diisocyanate), 10 parts of chain extender ethylene glycol, 0.25 parts of tin catalyst, 0.8 parts of heat stabilizer antioxidant 1010 and DLTP in a mass ratio of 1:1, 4 parts of flame retardant aluminum hydroxide modified nano-montmorillonite composite, 0.3 parts of ultraviolet absorber UV-327, and 0.6 parts of flow agent polypropylene wax. First, PCC and PLA-POLYOL were mixed and stirred at 60°C to form a uniform system, and then stabilizers, flame retardants and catalysts were added in sequence. TDI was added dropwise to control the NCO / OH molar ratio to 1.03:1. A prepolymerization reaction was carried out at 80°C for 80 minutes, and ethylene glycol was added for chain extension. After stirring for 25 minutes, the system was injected into a metal mold. The curing temperature was set to 90°C and the curing time was 2 hours. After cooling to room temperature, the system was demolded to obtain a polyurethane material sample C with strong light stability and good biodegradability.

[0041] Comparative Example 1:

[0042] Weigh 40 parts of a petrochemical-derived polyether polyol (MW ≈ 1000), 20 parts of TDI (diphenylmethane diisocyanate), 12 parts of a chain extender (1,4-butanediol), 0.3 parts of a catalyst (tin octoate), 0.5 parts of an antioxidant (1010), 0.2 parts of a UV absorber (UV-326), 4 parts of a traditional halogenated flame retardant (decabromodiphenyl ether), and 3 parts of a cosolvent (diethylene glycol). The polyether polyol and additives were mixed uniformly and stirred at 70°C for 20 minutes. TDI was then added dropwise to control the NCO / OH molar ratio to 1.05:1. The reaction was continued at 85°C for 90 minutes. The chain extender (1,4-butanediol) was then added and allowed to react for 30 minutes. The mixture was then injected into a mold and cured at 90°C for 2 hours. The mold was then demolded to obtain Comparative Sample D.

[0043] Comparative Example 2:

[0044] Weigh 45 parts of a petrochemical-based polyester polyol (such as PE-2000), 25 parts of MDI (diphenylmethane diisocyanate), 10 parts of ethylene glycol (chain extender), 0.4 parts of dibutyltin dilaurate (catalyst), 0.5 parts of DLTP (antioxidant), 0.25 parts of UV absorber UV-P, 5 parts of chlorinated paraffin (flame retardant), and 0.6 parts of polyethylene wax (flow agent). First, mix the polyester polyol with the additives and flame retardant at 65°C and stir until uniform. Then, add MDI, controlling the NCO / OH molar ratio to 1.1:1, and react at 80°C for 80 minutes. Then, add ethylene glycol to extend the chain and react for 30 minutes. The mixture is injected into a mold and cured at 95°C for 3 hours. Cool and demold to obtain Comparative Sample E.

[0045] Performance Testing

[0046] Experiment 1: Place each sample in a constant temperature and humidity chamber at 85°C and 85% relative humidity for 7 days. Remove the sample every day to record changes in mass and observe whether there is discoloration, deformation, or cracking.

[0047] Test indicators:

[0048] Quality retention rate (%) = quality after aging / initial quality × 100%

[0049] Tensile strength retention rate (tested according to GB / T1040.2-2006)

[0050] Surface color change (ΔE value measurement, according to GB / T11186.3-1989)

[0051] Microstructure observation (SEM scanning or optical microscopy)

[0052] The experimental results are shown in Table 1:

[0053]

[0054] Table 1

[0055] Samples A–C contain a bio-based polycarbonate polyol and a synergistic antioxidant (DLTP+1010) system, forming a more stable hydrogen bond network and thermal oxygen barrier, resulting in less deformation and slower performance degradation under high temperature and high humidity. Samples D and E, due to the use of traditional polyester polyether and ordinary antioxidants, have more obvious thermal hydrolysis and oxidation, resulting in accelerated degradation and increased surface defects.

[0056] Experiment 2: Using a UV aging chamber to simulate sunlight and a hot oxygen atmosphere, the anti-aging ability of different samples was examined. The UVB-313 lamp was set with a wavelength range of 290–315 nm.

[0057] Aging cycle:

[0058] UV irradiation: 60℃, 4h; condensation cycle: 50℃, 4h; total cycle time: 500 hours;

[0059] Test items (before and after aging):

[0060] Tensile strength change rate (GB / T528-2009)

[0061] Elongation change rate

[0062] Yellowing index (YI, according to ASTM E313)

[0063] Surface cracking grade (refer to ISO20340)

[0064] The experimental results are shown in Table 2:

[0065] Sample number Tensile strength change rate (%) Elongation change rate (%) Yellowing Index (YI) Surface cracking level (1 to 5) Sample A -4.3 -5.8 2.1 1(no cracks) Sample B -5.9 -6.7 2.5 1-2 (very slight) Sample C -6.8 -7.3 2.8 2(fine cracks) Sample D -19.4 -23.5 6.8 4 (obvious cracks) Sample E -25.1 -27.8 8.3 5 (severe cracks)

[0066] Table 2

[0067] The samples of the present invention use a synergistic system of ultraviolet absorbers UV-326 and UV-1577, which can effectively absorb high-energy radiation in the UVB region and prevent main chain breakage; samples D and E lack effective ultraviolet shielding and have a strong photo-oxidation synergistic aging effect, which is manifested as a rapid decline in mechanical properties, obvious cracking and yellowing on the surface.

[0068] The above shows and describes the basic principles, main features and advantages of the present invention; those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected; the scope of protection claimed in the present invention is defined by the attached claims and their equivalents.

Claims

1. A polyurethane resin material, characterized in that: The composition comprises the following components in parts by weight: 40-80 parts of bio-based polycarbonate diol, with a molecular weight of 500-3000 g / mol and a linear structure containing carbonate bonds in the main chain; 20-60 parts of bio-based diisocyanate, selected from one or more of lysine diisocyanate, castor oil-based isocyanate or linoleic acid-based isocyanate; 5 to 25 parts of a chain extender and a cross-linking agent, wherein the chain extender is selected from one or more of 1,4-butanediol and isosorbide, and the cross-linking agent is selected from one or more of trimethylolpropane and glycerol; 0.01-1 part of catalyst, selected from one of organic tin, bismuth or amine catalysts; 0.2-1 part of heat stabilizer, selected from pentaerythritol phosphate, phosphite or hindered phenol compound; 0.2 to 1.5 parts of an antioxidant composition, consisting of a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168; 1 to 5 parts of a toughening agent, selected from one or more of polybutadiene rubber, hydroxyl-terminated nitrile rubber, and polyester elastomer; 0.3-1 part of lubricating flow agent, selected from polyethylene wax, polypropylene wax or silicone flow agent; 0.1 to 0.5 parts of ultraviolet absorber, selected from UV-531, UV-328 or TINUVINP.

2. The polyurethane resin material according to claim 1, characterized in that: The bio-based polycarbonate diol is a polymer generated by copolymerization of carbon dioxide, propylene oxide and butylene oxide, and has a hydroxyl value of 30 to 70 mgKOH / g.

3. The polyurethane resin material according to claim 1, characterized in that: The bio-based diisocyanate has an NCO functionality of 2 and an NCO mass content of 20% to 28%.

4. The polyurethane resin material according to claim 1, characterized in that: The content of isosorbide in the chain extender is more than 60% of the total mass of the chain extender, and the mass ratio of trimethylolpropane to glycerol in the crosslinking agent is 2:1 to 4:

1.

5. The polyurethane resin material according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate, and its usage is 0.05% to 0.3% of the total mass.

6. The polyurethane resin material according to claim 1, characterized in that: The mass ratio of the primary antioxidant to the auxiliary antioxidant in the antioxidant composition is 1:2 to 1:

3.

7. The polyurethane resin material according to claim 1, characterized in that: The absorption peak of the ultraviolet absorber is within the range of 290 to 340 nm.

8. The polyurethane resin material according to claim 1, characterized in that: The polyurethane material has the following properties after being thermosetting and formed: tensile strength of 20 to 50 MPa, elongation at break of 150% to 300%, glass transition temperature of -10°C to 40°C, and thermal decomposition temperature of not less than 220°C.

9. The polyurethane resin material according to claim 1, characterized in that: The preparation method of the material comprises the following steps: Step 1: mixing bio-based polycarbonate diol and bio-based diisocyanate in a set ratio, reacting at 70° C. to 90° C. under a nitrogen atmosphere for 1 to 2 hours to form an isocyanate-terminated prepolymer; Step 2: adding a chain extender or a crosslinking agent, a catalyst, a heat stabilizer, an antioxidant, a toughening agent, a lubricant and an ultraviolet absorber to the obtained prepolymer in sequence, and stirring evenly at 80° C. to 100° C.; Step 3: Inject the stirred system into a mold, cure at 90°C to 110°C for 30 to 60 minutes, demold, heat treat at 120°C to 140°C for 20 to 40 minutes, and cool to obtain the target material.

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