High-strength full-closed-cell polyurethane foam and preparation method thereof
By preparing high-strength, fully closed-cell polyurethane foam, the problem of structural collapse of existing polyurethane foam under the trend of ultra-thinning has been solved, achieving high strength and high cushioning effect, which is suitable for electronic components and displays.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TAIHU FUSHI EXPO NEW MATERIALS CO LTD
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-05
AI Technical Summary
With the trend towards ultra-thinness, existing polyurethane foams with open or semi-open structures are prone to plastic deformation or collapse, making it difficult to meet the requirements of both thinness and high cushioning. In particular, their resistance to compression deformation and resilience are weak in flexible screen applications.
The preparation method of high-strength fully closed-cell polyurethane foam involves mixing polyether polyol, chain extender, catalyst, additives and modified isocyanate, coating it on a release film and then drying and curing it to form a micro-bubble structure, which enhances the strength and elasticity of the foam.
The prepared high-strength fully closed-cell polyurethane foam has excellent elasticity and mechanical properties, high impact absorption rate, and excellent 25% compression rebound strength. It is suitable for electronic components and displays, meeting the demand for thinner and lighter products.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of polyurethane foam technology, and in particular to a high-strength fully closed-cell polyurethane foam and its preparation method. Background Technology
[0002] Flexible OLED screens, also known as flexible displays, have achieved successful mass production, significantly benefiting not only the manufacturing of next-generation high-end smartphones but also profoundly impacting wearable devices due to their low power consumption and flexibility. Flexible screens are expected to see widespread application as personal smart terminals continue to penetrate the market. The cushioning and shock-absorbing OLED foam used within these screens saw 160-180μm thick SCF foam dominate the domestic market from 2021-2023, with 140-160μm thickness becoming the mainstream in 2024. The demand from end-users for thinner phones is driving screen module manufacturers to demand thinner and lighter screens. To meet these increasingly demanding applications, 80μm foam thicknesses are being developed and tested. However, most existing polyurethane foams are open-cell or semi-open-cell structures. Due to interconnected pore walls and poor structural continuity, they exhibit weak resistance to compressive deformation and resilience at the same thickness. With the trend towards ultra-thinness (e.g., thickness reduced to 80μm), the material needs to withstand higher stresses, and open-cell structures are prone to plastic deformation or collapse, affecting long-term cushioning stability. Thinning open-cell foam can easily lead to a sharp drop in support and a decrease in damping characteristics, making it difficult to simultaneously meet the dual requirements of "thinness" and "high cushioning." Therefore, there is an urgent need to develop a high-strength, fully closed-cell polyurethane foam, which is of great significance for the widespread application of polyurethane foam. Summary of the Invention
[0003] Based on the technical problems existing in the background technology, the present invention proposes a high-strength fully closed-cell polyurethane foam and its preparation method.
[0004] The present invention proposes a method for preparing high-strength fully closed-cell polyurethane foam, comprising the following steps: mixing polyether polyol, chain extender, catalyst and additives evenly to obtain mixture A; adding modified isocyanate to mixture A and mixing evenly to obtain mixture B; coating mixture B on a release film to obtain a film material; and drying and curing the film material to obtain the final product.
[0005] Preferably, the polyether polyol comprises a polyether polyol with a functionality of 2 and / or 3.
[0006] More preferably, the molecular weight of the difunctional polyether polyol is 2000, and the molecular weight of the trifunctional polyether polyol is 3000.
[0007] Preferably, the chain extender is selected from one or more of 1,4-butanediol and ethylene glycol.
[0008] Preferably, the catalyst is selected from one or more of tin-based catalysts, antimony-based catalysts, and amine-based catalysts.
[0009] More preferably, the tin catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, and stannous isooctanoate; the antimony catalyst is selected from one or more of antimony trioxide and antimony glycol; and the amine catalyst is selected from one or more of triethylenediamine, bis(dimethylaminoethyl) ether, and dimethylaminoethoxyethanol.
[0010] Preferably, the additive is selected from one or more of a foaming agent and a black paste.
[0011] More preferably, the foam leveling agent is polyether-modified polydimethylsiloxane, and the black paste is a mixture of carbon black.
[0012] Preferably, the modified isocyanate is a polytetrahydrofuran ether diol-modified diphenylmethane diisocyanate.
[0013] The role of modified isocyanate (modified MDI) is to enhance the strength of finished foam, thereby lowering the TG point of MDI chemicals, making it easier to store at room temperature and adapt to foam production processes.
[0014] Preferably, the mass fraction of isocyanate in the modified isocyanate is 11%-17%.
[0015] Preferably, the modified isocyanate is a modified isocyanate from Zhangjiagang Shoubo, with models M1310 and M1670.
[0016] Preferably, the mass ratio of the polyether polyol, chain extender, catalyst, and additive is 100:10-30:0.01-3:3-10.
[0017] The mass ratio of polyether polyol, chain extender, catalyst, and additives within a certain range helps to form a stable foam structure.
[0018] Preferably, the mass ratio of the mixture A to the modified isocyanate is 1:1-1.3.
[0019] The mass ratio of mixture A and modified isocyanate within a certain range helps to control the foam ratio index, finished product density, and hardness.
[0020] Preferably, the release film is a double-sided silicone-coated polyester film, and the release forces on both sides of the release film are 3-5 g / inch and 10-15 g / inch, respectively.
[0021] Controlling the release force on both sides of the release film within a certain range helps with the winding of the finished product, making the subsequent process of peeling off the release film simple, without air penetration or delamination.
[0022] Preferably, the thickness of the release film is 70-80 μm.
[0023] Preferably, the release film has a tensile strength ≥150MPa, an elongation at break ≥100%, a heat shrinkage rate ≤1.5%, and a release force difference of 3-5 times between the two sides.
[0024] Preferably, the coating method is blade coating.
[0025] Preferably, the release force of the release film surface on which the mixture B is coated is 10-15 g / inch.
[0026] Preferably, the drying temperature is 120-150°C.
[0027] Preferably, the drying process includes passing the film material through a five-temperature zone oven at a speed of 12-18 m / min.
[0028] More preferably, the temperatures of the five temperature zones are 120-130℃, 130-140℃, 130-140℃, 140-150℃, and 140-150℃, respectively.
[0029] The purpose of using different temperature zones for drying is to create a temperature gradient between zones, as the required temperature varies at different stages of the foaming reaction.
[0030] Preferably, the drying time is 1-2 minutes.
[0031] Preferably, the curing temperature is 30-80℃ and the curing time is 12-72h.
[0032] Controlling the temperature and time of maturation within a certain range helps the compounds to react fully, resulting in stable foam structure and properties.
[0033] A high-strength, fully closed-cell polyurethane foam is prepared by the above-described preparation method.
[0034] Applications of the above-mentioned high-strength fully closed-cell polyurethane foam or the high-strength fully closed-cell polyurethane foam prepared by the above-mentioned method in electronic components, displays and other fields.
[0035] The high-strength, fully closed-cell polyurethane foam proposed in this invention is used after removing the release film.
[0036] Preferably, the thickness of the polyurethane foam after the release film is removed is 70-90 μm.
[0037] The beneficial effects of this invention are as follows:
[0038] The high-strength, fully closed-cell polyurethane foam prepared by this invention is equivalent to a polyurethane elastomer filled with tiny air bubbles, exhibiting excellent elasticity, mechanical properties, and shock absorption. It can be applied in fields such as electronic components and displays for cushioning and shock absorption. The high-strength, fully closed-cell polyurethane foam prepared by this invention has an impact absorption rate of 38%-46%, a 25% compression rebound strength of 142-159 kPa, and a foam density of 781-836 kg / m³. 3 It exhibits good structural uniformity, which is of great reference value for its industrial application in electronic components, displays and other fields. Detailed Implementation
[0039] The technical solution of the present invention will be described in detail through specific embodiments.
[0040] In the following embodiments, the specific information regarding the raw materials used is as follows:
[0041] Foaming agent: polyether modified polydimethylsiloxane, manufacturer: Shoubo Electronics, brand: LG-70.
[0042] Black paste: a mixture of carbon black, manufactured by Shoubo Electronics, grade: RX-9932.
[0043] The release film is a 75μm double-sided silicone-coated release PET material, produced by Anhui Fuyin New Materials, with a residual rate of ≥80%, and release forces of 4g / inch and 12g / inch on both sides, respectively.
[0044] Preparation method of M1670: ①M1310 and MDI-50 are mixed in a mass ratio of 100:10.8 in a 200kg special reaction tank; ②Mix and mix at 30 r / min using a rotary mixer for 4 hours, and let stand for 24 hours before use.
[0045] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.
[0046] Example 1
[0047] A method for preparing high-strength, fully closed-cell polyurethane foam includes the following steps: 100 parts of polypropylene glycol (Nanjing Jurong Ningwu New Materials, NJ-220E) with a molecular weight of 2000 and a functionality of 2, 20 parts of 1,4-butanediol, 0.05 parts of a tin-based catalyst, dibutyltin dilaurate, 7 parts of a foam leveler, and 3 parts of black slurry are stirred using a dispersion disc agitator at a speed of 650 rpm to fully disperse the black slurry and thoroughly mix all raw materials to obtain mixture A; a modified isocyanate (modified MDI from Zhangjiagang Shoubo, model M1310) is added to mixture A and mixed. The mixture A and modified isocyanate were homogeneously mixed at a mass ratio of 1:1.3 to obtain mixture B. This mixture B was pumped into the coating head agitator using a rotary pump and coated onto the release film with a release force of 12 g / inch. After coating, the mixture was placed in an oven with a set temperature gradient: 130-140-140-140-140℃, with a total length of 20 m and a constant speed of 15 m / min for 80 seconds. After baking, the foam thickness was 80 μm. The foam was then rolled up after exiting the oven. The finished rolled product was then cured at 70℃ for 24 hours to ensure the stable shape of the foam after formation.
[0048] Example 2
[0049] A method for preparing high-strength, fully closed-cell polyurethane foam includes the following steps: 80 parts of polypropylene glycol (Nanjing Jurong Ningwu New Materials, NJ-220E) with a molecular weight of 2000 and a functionality of 2, 20 parts of polyether polyol (Nanjing Jurong Ningwu New Materials, NJ-330E) with a molecular weight of 3000 and a functionality of 3, 20 parts of 1,4-butanediol, 0.05 parts of dibutyltin dilaurate (a tin-based catalyst), 7 parts of foam leveling agent, and 3 parts of black slurry are stirred using a dispersion disc agitator at a speed of 650 rpm to fully disperse the black slurry and thoroughly mix all raw materials to obtain mixture A; modified isocyanate (Zhangjiagang) is added to mixture A. The modified MDI (model M1310) from Shoubo was mixed evenly. The mass ratio of mixture A to modified isocyanate was 1:1.2 to obtain mixture B. Mixture B was pumped into the coating head agitator using a rotary pump and coated onto the release film with a release force of 12 g / inch. After coating, it was placed in an oven with a set temperature gradient: 130-140-140-140-140℃, with a total length of 20 m and a constant speed of 15 m / min for 80 seconds. After baking, the foam thickness was 80 μm. After exiting the oven, it was wound up. The finished product was then cured at 40℃ for 72 h to ensure the stable shape of the foam after formation.
[0050] Example 3
[0051] A method for preparing high-strength, fully closed-cell polyurethane foam includes the following steps: 75 parts of polypropylene glycol (Nanjing Jurong Ningwu New Materials, NJ-220E) with a molecular weight of 2000 and a functionality of 2, 25 parts of polyether polyol (Nanjing Jurong Ningwu New Materials, NJ-330E) with a molecular weight of 3000 and a functionality of 3, 22 parts of 1,4-butanediol, 0.05 parts of dibutyltin dilaurate catalyst, 7 parts of foam leveling agent, and 3 parts of black slurry are stirred using a dispersion disc stirrer at a speed of 650 rpm to fully disperse the black slurry and thoroughly mix the raw materials to obtain mixture A; modified isocyanate (Zhangjiagang First) is added to mixture A. The modified MDI (model M1310) was mixed evenly. The mass ratio of mixture A to modified isocyanate was 1:1.25 to obtain mixture B. Mixture B was pumped into the coating head agitator using a rotary pump and coated onto the release film with a release force of 12 g / inch. After coating, it was placed in an oven with a set temperature gradient: 130-140-140-140-140℃, with a total length of 20 m and a constant speed of 15 m / min for 80 seconds. After baking, the foam thickness was 80 μm. After exiting the oven, it was wound up. The finished product was then cured at 40℃ for 72 h to ensure the stable shape of the foam after formation.
[0052] Example 4
[0053] A method for preparing high-strength, fully closed-cell polyurethane foam includes the following steps: 78 parts of polypropylene glycol (Nanjing Jurong Ningwu New Materials, NJ-220E) with a molecular weight of 2000 and a functionality of 2, 22 parts of polyether polyol (Nanjing Jurong Ningwu New Materials, NJ-330E) with a molecular weight of 3000 and a functionality of 3, 20 parts of 1,4-butanediol, 0.05 parts of dibutyltin dilaurate catalyst, 7 parts of foam leveling agent, and 3 parts of black slurry are stirred using a dispersion disc stirrer at a speed of 650 rpm to fully disperse the black slurry and thoroughly mix the raw materials to obtain mixture A; modified isocyanate (Zhangjiagang First) is added to mixture A. The modified MDI (model M1670) was mixed evenly. The mass ratio of mixture A to modified isocyanate was 1:1.15 to obtain mixture B. Mixture B was pumped into the coating head agitator using a rotary pump and coated onto the release film with a release force of 12 g / inch. After coating, it was placed in an oven with a set temperature gradient: 130-140-140-140-140℃, with a total length of 20 m and a constant speed of 15 m / min for 80 seconds. After baking, the foam thickness was 80 μm. After exiting the oven, it was wound up. The finished product was then cured at 70℃ for 24 hours to ensure the stable shape of the foam after formation.
[0054] The high-strength, fully closed-cell polyurethane foam was tested after removing the release film, measuring its closed-cell volume percentage (GB / T10799-2008), impact absorption rate (HG / T 2439-2011), 25% compression resilience (GB / T 20467-2006), tensile strength (GB / T 30776-2014), and apparent density (GB / T 6343-2009). The test results are shown in Table 1.
[0055] Table 1
[0056]
[0057] As can be seen from the data in Table 1, the high-strength fully closed-cell polyurethane foam prepared by this invention has a closed-cell volume percentage ≥95%, an impact absorption rate >30%, a 25% compression rebound strength >140kPa, a tensile strength >1000kPa, and an apparent density of 781-836kg / m³. 3 The high-strength, fully closed-cell polyurethane foam prepared by this invention possesses excellent elasticity and mechanical properties.
[0058] 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.
Claims
1. A method for preparing high-strength, fully closed-cell polyurethane foam, characterized in that, Includes the following steps: Polyether polyol, chain extender, catalyst and additives are mixed evenly to obtain mixture A; modified isocyanate is added to mixture A and mixed evenly to obtain mixture B; mixture B is coated on release film to obtain film material; film material is dried and cured to obtain the final product.
2. The preparation method according to claim 1, characterized in that, The polyether polyol includes polyether polyols with a functionality of 2 and / or 3; the chain extender is selected from one or more of 1,4-butanediol and ethylene glycol; the catalyst is selected from one or more of tin catalysts, antimony catalysts, and amine catalysts.
3. The preparation method according to claim 1, characterized in that, The modified isocyanate is a polytetrahydrofuran ether diol-modified diphenylmethane diisocyanate; the mass fraction of isocyanate in the modified isocyanate is 11%-17%.
4. The preparation method according to claim 1, characterized in that, The mass ratio of the polyether polyol, chain extender, catalyst, and additives is 100:10-30:0.01-3:3-10.
5. The preparation method according to claim 1, characterized in that, The mass ratio of the mixture A to the modified isocyanate is 1:1-1.
3.
6. The preparation method according to claim 1, characterized in that, The release film is a double-sided silicone-coated polyester film, with release forces of 3-5 g / inch and 10-15 g / inch on both sides, respectively.
7. The preparation method according to claim 1, characterized in that, The drying temperature is 120-150℃, and the drying time is 1-2 minutes.
8. The preparation method according to claim 1 or 7, characterized in that, The drying process involves passing the film material through a five-temperature zone oven at a speed of 12-18 m / min; the temperatures of the five temperature zones are 120-130℃, 130-140℃, 130-140℃, 140-150℃, and 140-150℃, respectively.
9. The preparation method according to claim 1, characterized in that, The curing temperature is 30-80℃, and the curing time is 12-72h.
10. A high-strength, fully closed-cell polyurethane foam, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.