Slow-resilience sponge material formula and manufacturing process thereof

Abstract

The invention relates to the technical field of sponge production, in particular to a formula of a slow-rebound sponge material and a manufacturing process of the slow-rebound sponge material. 30 to 50 parts of hyperbranched polyether polyol; 3-8 parts of nano cellulose crystal; 2 to 5 parts of a Diels-Alder polysiloxane microsphere; 0.8 to 1.4 parts of a zinc-imidazole composite catalyst; 0.4 to 0.6 part of a delayed amine catalyst; 5-15 parts of a supercritical CO2 foaming agent; and 1-3 parts of a chain extender. According to the slow-rebound sponge material formula and the manufacturing process thereof, the performance of the sponge is remarkably improved through optimization of the raw material ratio and modification treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of sponge production, and particularly relates to a slow rebound sponge material formula and its manufacturing process. Background Art

[0002] Due to its excellent cushioning performance and comfort, slow rebound sponge materials are widely used in furniture, car seats, sports equipment and other fields. Traditional slow rebound sponge materials are mainly made of polyurethane materials, and their manufacturing process is relatively simple, but there are some deficiencies in performance. For example, the slow rebound sponges in the prior art usually have problems such as too fast rebound speed, insufficient durability, and poor hygroscopicity, resulting in their inability to meet the high requirements of consumers for comfort and service life in actual applications. In addition, traditional manufacturing processes often have high requirements for the selection and proportion of raw materials and are difficult to achieve large-scale production, which limits their market promotion. Summary of the Invention

[0003] In order to overcome the shortcomings and deficiencies existing in the prior art, the purpose of the present invention is to provide a slow rebound sponge material formula and its manufacturing process, which significantly improve the performance of the sponge by optimizing the raw material ratio and modification treatment.

[0004] The present invention is achieved by the following technical solutions:

[0005] In the first aspect, the present invention discloses a slow rebound sponge material formula, which includes:

[0006] 40 - 60 parts of modified isocyanate;

[0007] 30 - 50 parts of hyperbranched polyether polyol;

[0008] 3 - 8 parts of nanocrystalline cellulose;

[0009] 2 - 5 parts of Diels - Alder polysiloxane microspheres;

[0010] 0.8 - 1.4 parts of zinc - imidazole composite catalyst;

[0011] 0.4 - 0.6 parts of delayed amine catalyst;

[0012] 5 - 15 parts of supercritical CO2 foaming agent;

[0013] 1 - 3 parts of chain extender.

[0014] In combination with the first aspect, further, the chain extender is 1,5 - naphthalenediamine chain extender.

[0015] In the second aspect, the present invention discloses a manufacturing process of a slow rebound sponge material, which includes the following steps:

[0016] S1. Weigh the raw materials according to the weight ratio of the formula:

[0017] S2. Take 3 - 8 parts of nanocrystalline cellulose, and modify it according to the following process:

[0018] Immerse it in a chloroform solution containing 5 - 10 wt% of polycaprolactone, and perform ultrasonic treatment at 50 - 70 °C for 1 - 3 hours;

[0019] Centrifuge to remove the ungrafted polycaprolactone;

[0020] Vacuum dry to obtain modified nanocrystalline cellulose with a surface grafting rate of 25 - 35%;

[0021] S3. In a reaction kettle under nitrogen protection, add 30 - 50 parts of hyperbranched polyether polyol, heat up to 40 - 60 °C and continuously stir, and sequentially add:

[0022] 3 - 8 parts of modified nanocrystalline cellulose, and disperse it at a high speed of 1500 - 2500 rpm for 25 - 35 min;

[0023] 2 - 5 parts of Diels - Alder polysiloxane microspheres, reduce the stirring rate to 450 - 550 rpm and mix for 10 - 20 min;

[0024] 1 - 3 parts of chain extender, maintain the temperature at 55 - 65 °C until completely dissolved to form a premixed system;

[0025] S4. Add 40 - 60 parts of modified isocyanate to another reaction kettle, and heat up to 35 - 45 °C;

[0026] Add the premixed system obtained in step S3, and control the dropping rate to make the NCO / OH molar ratio exactly 1.05:1;

[0027] Add 0.8 - 1.4 parts of zinc - imidazole composite catalyst, and after reacting for 1.5 - 2.5 h, obtain a prepolymer with a measured viscosity of 8500 mPa.s;

[0028] S5. Cool the prepolymer to 25 - 35 °C, add 0.4 - 0.6 parts of delayed amine catalyst, stir at 150 - 250 rpm for 5 - 10 min, and immediately transfer it to a pressure - resistant foaming mold;

[0029] S6. Inject 5 - 15 parts of supercritical CO2 foaming agent into the mold, and maintain for 25 - 40 min;

[0030] Release the pressure at a rate of 1.9 - 2.1 MPa / min to 4.9 - 5.1 MPa, and then release the pressure to atmospheric pressure at a rate of 0.25 - 0.35 MPa / min;

[0031] After the pressure release is completed, place the mold in an oven at 75 °C for 3 h to obtain a foam;

[0032] S7. Place the foam in a humidity-controlled chamber for 20 - 28 h for curing;

[0033] Process it into the target shape using a water jet cutting system;

[0034] Treat it in a hot press at 110 - 130 °C for 9 - 11 min.

[0035] Combined with the second aspect, further, in step S2, the power of the ultrasonic treatment is 300 W, the frequency is 40 kHz; the rotation speed of the centrifugal separation is 8000 rpm, and the time is 15 min; the temperature of the vacuum drying is 60 °C, and the time is 12 h.

[0036] Combined with the second aspect, further, in step S3, it is also necessary to add 0.5 parts of a monohydroxy polyether chain terminator to the premixed system and stir for 10 min to ensure homogenization.

[0037] Combined with the second aspect, further, in step S6, the pressure of the supercritical CO2 foaming agent is 10 - 15 MPa, and the solubility is 7 - 10 wt%.

[0038] Advantages of the present invention:

[0039] The present invention provides a novel slow-rebound sponge material formula and its manufacturing process. By optimizing the raw material ratio and modification treatment, the performance of the sponge is significantly improved. Specifically, the combination of modified isocyanate and hyperbranched polyether polyol not only improves the rebound performance of the sponge but also enhances its durability; at the same time, the introduction of nanocellulose crystals effectively improves the mechanical properties and hygroscopicity of the sponge, making the final product significantly improved in terms of comfort and service life; in addition, the use of Diels - Alder polysiloxane microspheres further enhances the structural stability of the sponge and avoids deformation problems during long-term use. Specific embodiments

[0040] To make the above objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0041] Example 1

[0042] A slow-rebound sponge material formula, including the following raw materials by weight:

[0043] 40 - 60 parts of modified isocyanate;

[0044] 30 - 50 parts of hyperbranched polyether polyol;

[0045] 3 - 8 parts of nanocrystalline cellulose;

[0046] 2 - 5 parts of Diels - Alder polysiloxane microspheres;

[0047] 0.8 - 1.4 parts of zinc - imidazole composite catalyst;

[0048] 0.4 - 0.6 parts of delayed amine catalyst;

[0049] 5 - 15 parts of supercritical CO₂ foaming agent;

[0050] 1 - 3 parts of chain extender.

[0051] Among them, the modified isocyanate is a trimer compound, introducing dynamic thiourethane bonds (-NH - C(=O)-S-), and its dynamic bond dissociation activation energy ≈ 80 kJ / mol (between hydrogen bond and covalent bond), achieving room - temperature stability / high - temperature reversibility. The NCO content is 22%, and the reaction activity is moderate to avoid out - of - control gelation.

[0052] Its physical properties show a viscosity of 2500 mPa·s (25 °C) and low volatility (vapor pressure < 0.1 Pa), ensuring processing safety.

[0053] The hyperbranched polyether polyol has a third - generation hyperbranched structure (functionality 16), with epoxy groups modified at the ends. The high degree of branching provides three - dimensional cross - linking sites, and the storage modulus is 3 times higher than that of linear polyols. The epoxy groups react with the amine chain extender to form a rigid aromatic ring structure.

[0054] Its physical properties show a hydroxyl value of 450 mgKOH / g, a viscosity of 8000 mPa·s (40 °C), and good compatibility with nanocrystalline cellulose.

[0055] The nanocrystalline cellulose is sourced from bamboo pulp, with β - 1,4 - glucan chains and polycaprolactone (PCL) grafted on the surface.

[0056] The hydroxyl density is 5.8 mmol / g, forming a hydrogen - bond network with the polyether polyol. The PCL chains (Tg ≈ - 60 °C) improve the interfacial toughness and inhibit stress cracking.

[0057] Its physical properties show a diameter of 50 nm, an aspect ratio > 50, and an axial tensile strength of 7 GPa (close to carbon fiber).

[0058] The Diels-Alder polysiloxane microspheres are composed of a polydimethylsiloxane backbone grafted with furan / maleimide groups. The reversible reaction temperature is 60 °C (k_reverse ≈ 0.01 s^-1), enabling thermal repair function. The siloxane segments reduce the surface energy (surface tension 22 mN / m), promoting cell stability.

[0059] Its physical properties include a particle size of 1.5 μm and a density of 1.12 g / cm 3 , and it can be uniformly suspended in the prepolymer.

[0060] The zinc-imidazole composite catalyst is a coordination complex of zinc ions and 2-methylimidazole, selectively catalyzing the isocyanate-hydroxy reaction (k1 / k2 > 100, suppressing side reactions).

[0061] Its physical properties include a thermal decomposition temperature of 180 °C, avoiding deactivation during the post-curing stage.

[0062] The zinc-imidazole composite catalyst and the delayed amine catalyst together form a composite catalyst system.

[0063] The physical properties of the supercritical CO2 foaming agent are a critical point of 31.1 °C / 7.38 MPa and a density of 0.47 g / cm 3 (supercritical state), and a high diffusion coefficient (10 -7 m 2 / s level) ensures rapid penetration into the polymer matrix. With zero surface tension, it can generate sub-micron-sized cells (the cell size is reduced by 80% compared to pentane foaming).

[0064] In this example, the chain extender is preferably 1,5-naphthalenediamine chain extender. Its chemical properties include a rigid planar naphthalene ring structure and two primary amine groups (the reaction activity is 50% lower than that of aliphatic amines), forming aromatic urea bonds with isocyanates (decomposition temperature > 250 °C), improving thermal stability, and the conjugated structure absorbing mechanical energy (the hysteresis loss is reduced by 30%).

[0065] Its physical properties include a melting point of 128 °C, and it needs to be heated and dissolved in the polyol system.

[0066] Example 2

[0067] A manufacturing process for slow rebound sponge materials includes the following steps:

[0068] S1. Weigh the raw materials according to the weight ratio of the formula described in Example 1:

[0069] S2. Take 3 - 8 parts of nanocrystalline cellulose and modify it according to the following process:

[0070] Immerse it in a chloroform solution containing 5 - 10 wt% of polycaprolactone and perform ultrasonic treatment at 50 - 70 °C for 1 - 3 hours;

[0071] Centrifugal separation is used to remove ungrafted polycaprolactone;

[0072] Vacuum drying is carried out to obtain modified nanocellulose with a surface grafting rate of 25 - 35%;

[0073] S3. In a reaction kettle under nitrogen protection, add 30 - 50 parts of hyperbranched polyether polyol, heat up to 40 - 60 °C and continuously stir, and successively add:

[0074] 3 - 8 parts of modified nanocellulose, disperse at a high speed of 1500 - 2500 rpm for 25 - 35 min;

[0075] 2 - 5 parts of Diels - Alder polysiloxane microspheres, reduce the stirring rate to 450 - 550 rpm and mix for 10 - 20 min;

[0076] 1 - 3 parts of chain extender, maintain the temperature at 55 - 65 °C until completely dissolved to form a premixed system;

[0077] S4. Add 40 - 60 parts of modified isocyanate to another reaction kettle, heat up to 35 - 45 °C;

[0078] Add the premixed system obtained in step S3, and control the dropping rate to make the NCO / OH molar ratio precisely 1.05:1;

[0079] Add 0.8 - 1.4 parts of zinc - imidazole composite catalyst, and after reacting for 1.5 - 2.5 h, obtain a prepolymer with a measured viscosity of 8500 mPa.s;

[0080] S5. Cool the prepolymer to 25 - 35 °C, add 0.4 - 0.6 parts of delayed amine catalyst, stir at 150 - 250 rpm for 5 - 10 min, and immediately transfer it to a pressure - resistant foaming mold;

[0081] S6. Inject 5 - 15 parts of supercritical CO2 foaming agent into the mold, and maintain for 25 - 40 min;

[0082] Release the pressure to 4.9 - 5.1 MPa at a rate of 1.9 - 2.1 MPa / min, and then release the pressure to atmospheric pressure at a rate of 0.25 - 0.35 MPa / min;

[0083] After the pressure release is completed, place the mold in an oven at 75 °C for 3 h to obtain a foam;

[0084] S7. Place the foam in a constant - humidity box for curing for 20 - 28 h;

[0085] Use a water jet cutting system to process it into the target shape;

[0086] Treat it in a hot press at 110 - 130 °C for 9 - 11 min.

[0087] Example 3

[0088] A manufacturing process for slow-rebound sponge material, comprising the following steps:

[0089] S1. Weigh the raw materials according to the weight ratio of the formula described in Example 1:

[0090] S2. Take 5 parts of nanocrystalline cellulose, and modify it according to the following process:

[0091] Immerse it in a chloroform solution containing 10 wt% of polycaprolactone, and perform ultrasonic treatment at 60 °C for 2 hours;

[0092] Centrifuge to remove the ungrafted polycaprolactone;

[0093] Vacuum dry to obtain modified nanocrystalline cellulose with a surface grafting rate of 30%;

[0094] S3. In a reaction kettle under nitrogen protection, add 40 parts of hyperbranched polyether polyol, heat up to 50 °C and continuously stir, and add successively:

[0095] 5 parts of modified nanocrystalline cellulose, disperse at a high speed of 20000 rpm for 30 min;

[0096] 4 parts of Diels-Alder polysiloxane microspheres, reduce the stirring rate to 500 rpm and mix for 15 min;

[0097] 2 parts of chain extender, maintain the temperature at 50 °C until completely dissolved to form a premixed system;

[0098] S4. Add 50 parts of modified isocyanate to another reaction kettle, and heat up to 40 °C;

[0099] Add the premixed system obtained in step S3, and control the dropping rate to make the NCO / OH molar ratio exactly 1.05:1;

[0100] Add 1 part of zinc-imidazole composite catalyst, and after reacting for 2 h, obtain a prepolymer with a measured viscosity of 8500 mPa·s;

[0101] S5. Cool the prepolymer to 30 °C, add 0.5 part of delayed amine catalyst, stir at 200 rpm for 8 min, and immediately transfer it to a pressure-resistant foaming mold;

[0102] S6. Inject 10 parts of supercritical CO2 foaming agent into the mold, and maintain for 30 min;

[0103] Release the pressure to 5 MPa at a rate of 2 MPa / min, and then release the pressure to atmospheric pressure at a rate of 0.3 MPa / min;

[0104] After the pressure release is completed, place the mold in an oven at 75 °C for 3 h to obtain a foam;

[0105] S7. Cure the foam in a humidity-controlled chamber for 25 h;

[0106] Process it into the target shape using a water jet cutting system;

[0107] Treat it at 120 °C for 10 min in a hot press.

[0108] Example 4

[0109] Conduct performance tests on the sponge finished product in Example 2. The data are as follows:

[0110] Table 1: Performance test items:

[0111]

[0112]

[0113] Key data comparative analysis:

[0114] 1. Indentation hardness and supportiveness:

[0115] Example 1: 85 N (moderate hardness, suitable for medical protective equipment and high-end seats); Traditional product: 60 N (relatively soft, prone to collapse after long-term use);

[0116] Advantage: The hardness is increased by 42%, and while the supportiveness is enhanced, the slow rebound characteristic is maintained.

[0117] 2. Compression set rate (durability):

[0118] Example 1: 4.2% (far lower than the industry requirement of 15%);

[0119] Traditional product: 12.5% (prone to plastic deformation at high temperatures);

[0120] Mechanism: The self-healing ability of the dynamic bond network (urethane + DA bond) reduces permanent deformation.

[0121] 3. Rebound time and temperature-sensitive response:

[0122] Standard environment at 25 °C: 10 s (meeting the definition of slow rebound);

[0123] Body temperature environment at 37 °C: 15 - 18 s (extended by 50%, adapting to the body temperature self-adaptive requirements of medical protective equipment);

[0124] Traditional product: No temperature sensitivity, large fluctuations in rebound time at high temperatures (±30%).

[0125] 4. Environmental protection and safety:

[0126] VOC emission: 0.02 mg / m 3(Only 13% of traditional products, meeting the requirements of baby products grade);

[0127] Flame retardancy: Self-extinguishing time ≤ 5s (traditional products cannot pass the CAL 117 test);

[0128] Biocompatibility: Toxicity level 0 (cell inhibition occurs in traditional products due to amine catalyst residues).

[0129] 5. Fatigue resistance (life prediction):

[0130] Thickness loss after 10,000 compressions: 3% (15% loss in traditional products);

[0131] Estimated life: Example 1 can reach 50,000 cycles (traditional products fail after only 15,000 cycles).

[0132] Table 2: Summary of performance advantages:

[0133]

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A slow rebound sponge material formula, characterized in that: include: 40-60 parts of modified isocyanate; 30-50 parts of hyperbranched polyether polyol; 3-8 parts of nanocellulose crystals; 2-5 parts of Diels-Alder polysiloxane microspheres; 0.8-1.4 parts of zinc-imidazole composite catalyst; Delayed amine catalyst 0.4-0.6 parts; 5-15 parts of supercritical CO2 foaming agent; Chain extender 1-3 parts.

2. A slow rebound sponge material formula according to claim 1, characterized in that: The chain extender is 1.5-naphthalene diamine chain extender.

3. A manufacturing process of a slow-rebound sponge material, characterized in that: The following steps are involved: S1. Raw materials are weighed according to the weight ratio of the formula described in claim 1 or 2: S2. Take 3-8 portions of nanocellulose crystals and modify them according to the following process: Immerse in a chloroform solution containing 5-10 wt% polycaprolactone and perform ultrasonic treatment at 50-70° C. for 1-3 hours; The ungrafted polycaprolactone was removed by centrifugation; Vacuum drying to obtain modified nanocellulose with a surface grafting rate of 25-35%; S3. In a nitrogen-protected reactor, add 30-50 parts of hyperbranched polyether polyol, raise the temperature to 40-60°C and continue stirring, and add in sequence: 3-8 parts of modified nanocellulose, disperse at high speed of 1500-2500 rpm for 25-35 minutes; 2-5 parts of Diels-Alder polysiloxane microspheres, stirring speed reduced to 450-550 rpm and mixed for 10-20 minutes; 1-3 parts of chain extender, maintain the temperature at 55-65°C until it is completely dissolved to form a premixed system; S4, add 40-60 parts of modified isocyanate into another reaction kettle and heat it to 35-45°C; Add the premixed system obtained in step S3, and control the dropping speed so that the NCO / OH molar ratio is exactly 1.05:1; 0.8-1.4 parts of zinc-imidazole composite catalyst were added, and the reaction was continued for 1.5-2.5 hours to obtain a prepolymer having a measured viscosity of 8500 mPa.s; S5, cool the prepolymer to 25-35°C, add 0.4-0.6 parts of delayed amine catalyst, stir at 150-250 rpm for 5-10 min, and immediately transfer to a pressure-resistant foaming mold; S6, inject 5-15 parts of supercritical CO2 foaming agent into the mold and maintain for 25-40 minutes; Release the pressure to 4.9-5.1MPa at a rate of 1.9-2.1MPa / min, and release the pressure to normal pressure at a rate of 0.25-0.35MPa / min; After the pressure release was completed, the mold was placed in an oven at 75°C for 3 h to obtain a foamed body; S7, placing the foam in a constant humidity chamber for aging for 20-28 hours; Use water jet cutting system to process into target shape; Process in a hot press at 110-130°C for 9-11 minutes.

4. The manufacturing process of the slow-rebound sponge material according to claim 3, characterized in that: In step S2, the power of ultrasonic treatment is 300 W and the frequency is 40 kHz; the rotation speed of centrifugal separation is 8000 rpm and the time is 15 min; the temperature of vacuum drying is 60° C. and the time is 12 h.

5. The manufacturing process of the slow-rebound sponge material according to claim 3, characterized in that: In step S3, 0.5 parts of monohydroxy polyether chain terminator is added to the premixed system and stirred for 10 minutes to ensure homogeneity.

6. The manufacturing process of the slow-rebound sponge material according to claim 3, characterized in that: In step S6, the supercritical CO2 foaming agent has a pressure of 10-15 MPa and a solubility of 7-10 wt%.

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