A polyurethane resin composition, a polyurethane material, and applications thereof

Abstract

The present application relates to a kind of polyurethane resin composition, polyurethane material and its application, the polyurethane resin composition includes the following weight parts of component: blocked polyurethane prepolymer 100 parts, amine crosslinking agent 4-10 parts, catalyst 0.1-10 parts;The preparation raw material of the blocked polyurethane prepolymer includes the combination of active hydrogen component, isocyanate and blocking agent;The amine crosslinking agent includes 4,4-diamino dicyclohexyl methane (trans-trans structure is 13~20%);The catalyst is organic bismuth class.The polyurethane resin composition provided by the present application is not only safe and environmentally friendly, but also can be quickly cured, so that production efficiency is improved;It can be used for water-based PUD, leather slurry, hot melt adhesive, and the obtained polyurethane material simultaneously has excellent hydrolysis resistance, adhesion, wear resistance and alcohol resistance.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane, and specifically relates to a polyurethane resin composition, polyurethane materials and their applications. Background Technology

[0002] Polyurethane materials use isocyanate as the main raw material, with a rich variety of raw materials and diverse formulations. They possess excellent chemical resistance, abrasion resistance, and toughness, and are widely used in industries such as rail transportation, electronic devices, coatings, wood, and leather as coatings, adhesives, synthetic leather, elastomers, and paving materials. Specifically, they are classified into solvent-based polyurethane, solvent-free two-component polyurethane, waterborne polyurethane, and blocked polyurethane.

[0003] Solvent-based polyurethanes achieve solvent evaporation through high-temperature baking, causing environmental pollution. Solvent-free two-component polyurethanes have high viscosity and require specialized equipment and storage due to their open NCO structure. Waterborne polyurethanes achieve environmental friendliness by using water instead of solvents, but their overall performance still lags behind traditional solvent-based polyurethanes, especially in hydrolysis resistance (e.g., Chinese patent CN108779200A). Block-type polyurethanes can be stored stably at room temperature, and some systems, when combined with crosslinking agents and catalysts, can achieve rapid high-temperature curing, but they still suffer from high internal stress, and their overall performance does not meet requirements (e.g., Chinese patent CN109266294A). Therefore, developing an environmentally friendly, safe, convenient, and high-performance polyurethane resin material is a continuous endeavor for the industry.

[0004] Chinese patent CN 117343267 A discloses a type of closed polyurethane composition that produces leather base with high peel strength, excellent heat resistance, low-temperature folding resistance and hydrolysis resistance. The process is advanced, but its solvent resistance and abrasion resistance are not obvious. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a polyurethane resin composition, a polyurethane material, and their applications. The purpose of this invention is to provide a polyurethane material that is easy to produce, environmentally friendly, and exhibits strong adhesion, hydrolysis resistance, alcohol abrasion resistance, and excellent wear resistance.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A polyurethane resin composition comprising the following components in parts by weight:

[0008] 100 parts of blocked polyurethane prepolymer, 4-10 parts (e.g., 5, 6, 7, 8, 9 parts) of amine crosslinking agent, and 0.1-10 parts (e.g., 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9 parts) of catalyst.

[0009] The raw materials for preparing the blocked polyurethane prepolymer include a combination of active hydrogen components, isocyanates, and blocking agents; the amine crosslinking agent includes 4,4-diaminodicyclohexylmethane, wherein the content of the trans-trans structure in the 4,4-diaminodicyclohexylmethane is 13-20 wt%, for example, 14, 15, 16, 17, 18, 19, 20%, etc.; the catalyst is an organic bismuth.

[0010] In this invention, the catalyst is a tertiary amine or organometallic compound, such as tertiary amines like N,N-dimethylcyclohexylamine, triethylenediamine, N-methylmorpholine, and triethanolamine, organotin compounds, organobismuth compounds, or organozinc compounds. Organobismuth catalysts are preferred, such as any one or at least a combination of two of BiCAT Z(M), BiCAT 3228(M), BiCAT 8, and BiCAT 8108 from Leading Chemicals Inc.

[0011] In this invention, a combination of a closed-type polyurethane prepolymer, a specific-structure amine curing agent, and a catalyst is used to achieve the following: First, a long shelf life at room temperature, which facilitates production and is environmentally friendly; second, desealing at high temperatures, with the organic bismuth catalyst exhibiting excellent high-temperature catalytic effect, resulting in polyurethane materials with strong adhesion; and third, the polyurethane obtained using 4,4-diaminodicyclohexylmethane (with 13-20% of the trans-trans structure) has a large steric hindrance in the transition state during hydrolysis, making it less prone to hydrolysis, and the resulting polyurethane material exhibits excellent hydrolysis resistance, adhesion, and alcohol rubbing resistance.

[0012] In this invention, the raw materials for preparing the closed-type polyurethane prepolymer include the following components in parts by weight:

[0013] The active hydrogen component is 45-85 parts, for example, 46, 50, 55, 60, 65, 70, 75, 80, 85 parts, etc.;

[0014] Chain extender 0-5 parts, for example 1, 2, 3, 4, 5 parts, etc.;

[0015] Crosslinking agent 0-3 parts, for example 0.5, 1, 1.5, 2, 2.5, 3 parts, etc.;

[0016] Isocyanate component 15-45 parts, for example 15, 18, 21, 24, 27, 30, 33, 36, 40, 42, 45 parts, etc.;

[0017] Use 3-10 parts of sealant, for example, 3, 4, 5, 6, 7, 8, 9, or 10 parts.

[0018] In this invention, the active hydrogen component comprises polyester polyols and / or polyether polyols. The polyester polyols include any one or at least two combinations of polypentyl adipate diol, polybutylene adipate diol, polyhexyl adipate diol, polyethylene adipate diol, polymethyl propylene adipate diol, polypropylene adipate diol, polydiethylene adipate diol, polybutylene adipate methyl propylene adipate diol, or polycaprolactone diol. The polyether polyols include any one or at least two combinations of polypropylene oxide diol, polyethylene oxide diol, polytetramethylene ether diol, or polymer polyols. The molecular weight of the active hydrogen component is 400-3000, for example, 500, 800, 1000, 1500, 2000, 2500, 3000, etc.

[0019] In this invention, the chain extender includes any one or at least a combination of two of the following: 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, cyclohexanediol, 1,6-hexanediol, 3,3'-dichloro-4,4'-diphenylmethanediamine, 3,5-diethyltoluenediamine, triethanolamine, diethanolamine, methyldiethanolamine, 4,4'-bis(sec-butylamino)diphenylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, and 1,3-cyclohexanediamine.

[0020] In this invention, the crosslinking agent includes one or at least two combinations of trimethylolpropane, pentaerythritol, glycerol, toluene diamine, triisopropanolamine, 4,4'-diaminodicyclohexylmethane, isophorone diamine, and 4,4'-bis-sec-butylaminodiphenylmethane.

[0021] In this invention, the blocking agent includes one or at least two combinations of methyl ethyl ketone oxime, 3,5-dimethylpyrazole, pyrazole, and glyceryl carbonate.

[0022] In this invention, the isocyanate component includes any one or at least a combination of two of 2,4-toluene diisocyanate, toluene 2,6-diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

[0023] In this invention, the preparation method of the closed-type polyurethane prepolymer includes the following steps:

[0024] First, add the active hydrogen component and chain extender at 20-45℃ and stir for 10-20 min. Then, add the isocyanate component dropwise to the flask over 0.5-1 h and react at 65-85℃ for 2-5 hours. Add the crosslinking agent and continue the reaction until the NCO content is less than the theoretically calculated value. After adding the blocking agent, react at 70-90℃ for 0.5-3 hours to carry out the end-capping reaction until the NCO content in the system is less than 0.1%. Cool to room temperature to obtain the blocked polyurethane prepolymer.

[0025] In the polyurethane resin composition described in this application, the blocked polyurethane prepolymer is generated by the reaction of isocyanate and hydroxyl component, has a small molecular weight and low viscosity, and a suitable unblocking temperature, which is beneficial for processing.

[0026] On the other hand, a polyurethane material is formed by curing the aforementioned polyurethane resin composition at 120-150°C for 2-5 minutes.

[0027] On the other hand, the aforementioned polyurethane resin composition is used in waterborne PUDs, polyurethane adhesives, and polyurethane leather pastes.

[0028] Compared with the prior art, this application has the following superior effects:

[0029] The polyurethane composition obtained by this invention has a simple production process and a wide range of applications. It can be cured at 120-150℃ for 1-3 minutes to form a polyurethane material, which can meet the performance requirements of various downstream applications.

[0030] The polyurethane materials prepared by the polyurethane composition of the present invention have excellent adhesion, good alcohol rubbing resistance, abrasion resistance and hydrolysis resistance, and the hydrolysis peel strength retention rate can reach more than 90%. Detailed Implementation

[0031] The technical solution of this application will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be construed as limiting the scope of this application.

[0032] The main sources of raw materials involved in the following embodiments are as follows:

[0033]

[0034]

[0035] Example 1

[0036] First, add 55 g of polypropylene oxide diol (Mn=3000) and 3 g of chain extender 1,4-butanediol at 20 °C and stir for 10 min. Then, add 15 g of toluene-2,4-diisocyanate dropwise to a flask over 30 min and react at 70 °C for 3 hours. Add 1 g of crosslinking agent pentaerythritol and continue the reaction until the NCO content is less than the theoretically calculated value. Add 4 g of blocking agent 3,5-dimethylpyridine and react at 70 °C for 3 hours to perform an end-capping reaction until the NCO content in the system is less than 0.1%. Cool to room temperature to obtain a blocked polyurethane prepolymer.

[0037] 100 g of the obtained closed polyurethane prepolymer was mixed with 6 g of diaminodicyclohexylmethane (13% of the anti-antibody) and 10 g of catalyst DMCHA at 25 °C to obtain a polyurethane resin composition, and the viscosity of the composition was tested.

[0038] The obtained polyurethane resin composition was coated onto the polished tinplate using a 300μm wire rod. After 24 hours, it was placed in a 130℃ oven for 4 minutes to bake and cure, thus obtaining the polyurethane material. The peel strength and peel strength retention rate were then tested.

[0039] Example 2

[0040] First, 45 g of polybutylene adipate diol (Mn=2000) and 2 g of chain extender propylene glycol were added at 30 °C and stirred for 20 min. Then, 20 g of 4,4'-diisocyanate diphenylmethane was added dropwise to a flask over 45 min and reacted at 65 °C for 5 hours. Next, 2 g of crosslinking agent toluene diamine was added, and the reaction continued until the NCO content was less than the theoretically calculated value. Finally, 3 g of blocking agent 3,5-dimethylpyrazole was added, and the reaction was carried out at 90 °C for 0.5 hours to perform end-capping until the NCO content in the system was less than 0.1%. The mixture was then cooled to room temperature to obtain a blocked polyurethane prepolymer.

[0041] 100 g of the obtained closed polyurethane prepolymer was mixed with 4.7 g of diaminodicyclohexylmethane (16% of the anti-antibody) and 8 g of zinc isooctanoate catalyst at 30 °C to obtain a polyurethane resin composition, and the viscosity of the composition was tested.

[0042] The obtained polyurethane resin composition was coated onto the polished tinplate using a 300μm wire rod. After 24 hours, it was placed in a 150℃ oven for 2 minutes to bake and cure, thus obtaining the polyurethane material.

[0043] Example 3

[0044] First, 35 g of polypropylene oxide diol (Mn=400), 35 g of polypropylene adipate diol (Mn=2000), and 1 g of ethanolamine were added at 45 °C and stirred for 14 min. Then, 45 g of 4,4-diisocyanate dicyclohexylmethane was added dropwise to a flask over 60 min, and the reaction was carried out at 85 °C for 2 hours. Next, 3 g of crosslinking agent isophorone diamine was added, and the reaction continued until the NCO content was less than the theoretically calculated value. Finally, 9.2 g of blocking agent methyl ethyl ketone oxime was added, and the reaction was carried out at 80 °C for 1.5 hours to perform an end-capping reaction until the NCO content in the system was less than 0.1%. The mixture was then cooled to room temperature to obtain a blocked polyurethane prepolymer.

[0045] 100 g of the obtained closed polyurethane prepolymer was mixed with 9.3 g of diaminodicyclohexylmethane (20% of the trans-trans) and 0.5 g of catalyst bismuth isooctanoate BiCAT 8210 at 35 °C to obtain a polyurethane resin composition. The viscosity and gel time at 120 °C of the composition were tested.

[0046] The obtained polyurethane resin composition was coated onto the polished tinplate using a 300μm wire rod. After 24 hours, it was placed in an oven at 140℃ for 5 minutes to bake and cure, thus obtaining the polyurethane material.

[0047] Example 4

[0048] First, 60 g of polyethylene adipate glycol (Mn=1000) and 20 g of polypropylene oxide glycol (Mn=500) were added at 35°C and stirred for 18 min. Then, 40 g of isophorone diisocyanate was added dropwise to a flask over 50 min, and the mixture was reacted at 75°C for 4 hours. Next, 5 g of chain extender 4,4'-bis-sec-butylaminodiphenylmethane was added, and the reaction continued until the NCO content was less than the theoretically calculated value. Finally, 7.3 g of blocking agent methyl ethyl ketone oxime was added, and the mixture was reacted at 75°C for 2 hours to perform an end-capping reaction until the NCO content in the system was less than 0.1%. The mixture was then cooled to room temperature to obtain a blocked polyurethane prepolymer.

[0049] 100 g of the obtained closed polyurethane prepolymer was mixed with 7.1 g of diaminodicyclohexylmethane (13% of the anti-antibody) and 5 g of dibutyltin dilaurate catalyst at 25 °C to obtain a polyurethane resin composition, and the viscosity of the composition was tested.

[0050] The obtained polyurethane resin composition was coated onto the polished tinplate using a 300μm wire rod. After 24 hours, it was placed in a 120℃ oven for 5 minutes to bake and cure, thus obtaining the polyurethane material. The peel strength and peel strength retention rate were then tested.

[0051] Comparative Example 1

[0052] In Example 1, 6 grams of diaminodicyclohexylmethane (13% of the trans-trans) was replaced with 6 grams of diaminodicyclohexylmethane (23% of the trans-trans), while all other substances and conditions remained unchanged.

[0053] Comparative Example 2

[0054] In Example 1, 6 grams of diaminodicyclohexylmethane (13% of the trans-trans) was replaced with 6 grams of diaminodicyclohexylmethane (11% of the trans-trans), while all other substances and conditions remained unchanged.

[0055] Comparative Example 3

[0056] In Example 1, 6 grams of diaminodicyclohexylmethane (13% of the trans-trans) was replaced with the same molar amount of isophorone diamine, while all other substances and conditions remained unchanged.

[0057] Test method:

[0058] The NCO content was tested using a point titrator according to GB / T 12009.4-2006; the viscosity of the polyurethane composition was tested according to GB / T 10247-2008; the unsealing temperature of the polyurethane resin composition was tested using the DSC method at a heating rate of 10℃ / min; the surface drying time of the paint film was tested according to GB / T 1728-2020; the adhesion was tested according to GB / T9286-88 "Cross-cut test of paint and varnish films"; the alcohol resistance of the paint film was tested according to ASTM D 5402 to determine the number of times the paint film needed to break after being wiped with ethanol; the abrasion resistance of the polyurethane material was tested according to GB / T1768-2006; and the initial peel strength was tested according to GB / T 2792-2014. After placing the polyurethane material sample at 70℃ / 95% humidity for 5 weeks, the peel strength was tested again, and the peel strength retention rate was calculated.

[0059] The performance test results of the polyurethane materials in the examples and comparative examples are shown in the table below:

[0060]

[0061]

[0062] As shown in the table above, the polyurethane resin composition provided by this invention has a low viscosity, a suitable unsealing temperature, and can cure rapidly at a suitable temperature. After complete curing, it exhibits high peel strength. Comparing Comparative Examples 1 and 2 with Examples 1-4, it can be seen that when the content of the anti-anti-diaminodicyclohexylmethane is in the range of 13% to 20%, the polyurethane composition has a lower viscosity, better processability, and the resulting polyurethane material exhibits excellent adhesion, alcohol rub resistance, abrasion resistance, and initial peel strength. Furthermore, it shows higher peel retention rate and better water resistance after exposure to high humidity. Comparing Comparative Example 3 with Examples 1-4, it can be seen that the polyurethane composition obtained using diaminodicyclohexylmethane as an amine crosslinking agent has a suitable viscosity, better processability, and the resulting polyurethane material exhibits excellent adhesion, alcohol rub resistance, abrasion resistance, and initial peel strength. Furthermore, it shows higher peel retention rate and better water resistance after exposure to high humidity.

Claims

1. A polyurethane resin composition, characterized in that, The polyurethane resin composition comprises the following components in parts by weight: 100 parts of closed-cell polyurethane prepolymer; 4-10 parts of amine crosslinking agent; Catalyst 0.1-10 parts; The raw materials for preparing the blocked polyurethane prepolymer include a combination of active hydrogen components, isocyanates, and blocking agents; the catalyst is a tertiary amine or an organometallic compound. The amine crosslinking agent is 4,4-diaminodicyclohexylmethane, wherein the content of the trans-trans structure in the 4,4-diaminodicyclohexylmethane is 13~20wt%.

2. The polyurethane resin composition according to claim 1, characterized in that, The raw materials for preparing the closed-type polyurethane prepolymer include the following components in parts by weight: 45-85 parts of active hydrogen component; Chain extender 0-5 parts; 0-3 parts of crosslinking agent; Isocyanate component: 15-45 parts; 3-10 parts of sealant.

3. The polyurethane resin composition according to claim 2, characterized in that, The active hydrogen component includes polyester polyols and / or polyether polyols.

4. The polyurethane resin composition according to claim 3, characterized in that, The polyester polyol comprises any one or at least two combinations of poly(neopentyl adipate) diol, poly(butylene adipate) diol, poly(hexylene adipate) diol, poly(ethylene adipate) diol, poly(methyl propylene adipate) diol, poly(propylene adipate) diol, poly(diethylene adipate) diol, poly(butylene adipate) methyl propylene adipate diol, or polycaprolactone diol; and / or The polyether polyol includes any one or at least two combinations of polypropylene glycol, polyethylene glycol, polytetramethylene ether glycol, or polymer polyols.

5. The polyurethane resin composition according to claim 4, characterized in that, The molecular weight of the active hydrogen component is 400-3000.

6. The polyurethane resin composition according to claim 2, characterized in that, The chain extender includes any one or at least a combination of two of the following: 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, cyclohexanediol, 1,6-hexanediol, 3,3'-dichloro-4,4'-diphenylmethanediamine, 3,5-diethyltoluenediamine, triethanolamine, diethanolamine, methyldiethanolamine, 4,4'-bis(sec-butylamino)diphenylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, and 1,3-cyclohexanediamine.

7. The polyurethane resin composition according to claim 2, characterized in that, The crosslinking agent includes one or at least two combinations of trimethylolpropane, pentaerythritol, glycerol, toluene diamine, triisopropanolamine, 4,4'-diaminodicyclohexylmethane, isophorone diamine, and 4,4'-bis-sec-butylaminodiphenylmethane.

8. The polyurethane resin composition according to claim 2, characterized in that, The blocking agent includes one or a combination of at least two of methyl ethyl ketone oxime, 3,5-dimethylpyrazole, pyrazole, and glyceryl carbonate.

9. The polyurethane resin composition according to claim 2, characterized in that, The isocyanate component includes any one or at least two combinations of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

10. The polyurethane resin composition according to claim 1, characterized in that, The preparation method of the closed-type polyurethane prepolymer includes the following steps: First, add the active hydrogen component and chain extender at 20~45℃ and stir for 10~20 min. Then, add the isocyanate component dropwise to the flask within 0.5~1 h and react at 65~85℃ for 2~5 hours. Add the crosslinking agent and continue the reaction until the NCO content is less than the theoretical calculated value. After adding the blocking agent, react at 70~90℃ for 0.5~3 hours to carry out the end-capping reaction until the NCO content in the system is less than 0.1%. Cool to room temperature to obtain the blocked polyurethane prepolymer.

11. A polyurethane material, characterized in that, The polyurethane material is formed by curing the polyurethane resin composition according to any one of claims 1-10 at 120-150°C for 2-5 minutes.

12. The use of the polyurethane resin composition according to any one of claims 1-10 in waterborne PUDs, polyurethane adhesives, and polyurethane leather pastes.

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