Preparation process of rigid foam polyurethane insulation board

Abstract

The invention discloses a preparation process of a rigid foam polyurethane insulation board, and relates to the technical field of thermal insulation materials, and the preparation process comprises the following steps: preparing a rigid foam polyurethane core material and compounding the core material with a vacuum protection surface layer; the hard foam polyurethane core material comprises the following components in parts by weight: 100 parts of polyether polyol, 1 part of a catalyst, 0.3 part of water, 1 part of a foam stabilizer, 3 parts of an expandable graphite-silica fume compound and 5-30 parts of an SEBS modifier; the vacuum protection surface layer is an aluminum foil bag; the compounding of the core material and the vacuum protection surface layer specifically comprises the following steps: loading the rigid foam polyurethane core material into an aluminum foil bag, and carrying out vacuum packaging to obtain the rigid foam polyurethane insulation board; a better heat preservation and heat insulation effect can be achieved, and material fission or damage caused by external environment changes is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation materials, and in particular to a preparation process of a rigid foam polyurethane thermal insulation board. Background Art

[0002] Vacuum insulation panels are a new type of thermal insulation material with excellent thermal insulation properties. In the field of cold chain transportation, they can greatly reduce the energy consumption problem caused by the poor thermal insulation performance of thermal insulation materials. Most existing vacuum insulation panels are composed of a filling core material and a vacuum protective surface layer. It effectively avoids heat transfer caused by air convection and thus has a good thermal insulation effect. The core material is often made of polyurethane foam as raw material. The rigid foam polyurethane contains a large number of closed tiny bubbles. The size of the bubbles is usually between tens and hundreds of microns and is evenly distributed, which effectively prevents gas convection and heat conduction.

[0003] For example, the Chinese patent, application number CN202211353093.7, is a fully water-open-cell rigid polyurethane foam and its preparation method. The foam includes a polyether polyol mixture, polymethylene polyphenyl polyisocyanate, and a synergistic reinforcement system of microsilica powder modified by expandable graphite and silane coupling agent. The ultrasonic intercalation process assisted by xylene is used to expand the spacing between expandable graphite flakes to provide nano-confined space for microsilica powder. The silane coupling agent (KH-550) forms a gradient grafting layer on the surface of the microsilica powder to achieve a chemical bond transition from an inorganic core to an organic shell. The spatial steric effect of the modified microsilica powder between the graphite flakes and the Si-OC bond formed at the graphite / microsilica powder interface construct a three-dimensional stress transfer network, thereby improving energy dissipation efficiency.

[0004] However, the surface of expandable graphite is a hydrophobic carbon layer (contact angle > 100°), while the surface of silane-modified microsilica powder is a polar Si-O-Si bond (contact angle < 30°). The interface between the two is thermodynamically incompatible, leading to micron-scale phase separation within the composite, which in turn leads to a decrease in compressive strength and the emergence of crack propagation paths in the pore walls, ultimately resulting in a decrease in thermal insulation and reduced mechanical strength. Summary of the Invention

[0005] The embodiment of the present application solves the problem in the prior art that graphite and silicon powder are separated due to thermodynamic incompatibility, resulting in a decrease in thermal insulation capacity, by providing a preparation process for a rigid foam polyurethane insulation board, thereby achieving stronger thermal insulation capacity.

[0006] The embodiment of the present application provides a process for preparing a rigid foam polyurethane insulation board, comprising preparing a rigid foam polyurethane core material and compounding the core material with a vacuum protective surface layer;

[0007] The rigid polyurethane foam core material includes, by weight: 100 parts of polyether polyol, 1 part of catalyst, 0.3 parts of water, 1 part of foam stabilizer, 3 parts of expandable graphite-microsilica powder composite, and 5-30 parts of SEBS modifier;

[0008] The SEBS modifier is a styrene-ethylene-butylene-styrene triblock copolymer, and the SEBS modifier is an ionic liquid (IL) modified SEBS particle, the ionic liquid (IL) is 1-butyl-3-methylimidazolium hexafluorophosphate, and the addition amount is 0.5-3 parts by weight;

[0009] The vacuum protection surface is an aluminum foil bag;

[0010] The core material and the vacuum protection surface layer are composited as follows: the rigid foam polyurethane core material is placed in an aluminum foil bag and vacuum-sealed to obtain the rigid foam polyurethane insulation board.

[0011] Furthermore, the polyether polyol is a rigid polyether polyol with a hydroxyl value of 360-390 mgKOH / g using glycerol as an initiator, a rigid polyether polyol with a hydroxyl value of 400-600 mgKOH / g using sorbitol as an initiator, and a rigid polyether polyol with a hydroxyl value of 250-500 mgKOH / g using propylene glycol as an initiator, and the weight ratio of the three is 1:1:1.

[0012] Furthermore, the preparation method of the expandable graphite-microsilica fume composite is as follows:

[0013] The expandable graphite is placed in xylene, ultrasonically dispersed, microsilica powder is added, mixed evenly, the solid matter is filtered and washed, and dried to obtain a composite. The weight ratio of the expandable graphite to the microsilica powder is 1:0.3.

[0014] Furthermore, the catalyst is a mixture of triethanolamine and dibutyltin dilaurate; the weight ratio of triethanolamine to dibutyltin dilaurate is 1:1.

[0015] Furthermore, the process of ionic liquid (IL) modified SEBS particles is as follows: the ionic liquid is heated to 80°C, and after the viscosity is less than 50mPa·s, it is injected into SEBS that has been melted at 180°C in advance according to the weight ratio of IL / SEBS = 10%, and maintained at a shear rate of 600-800rpm for 5 minutes, and then cross-linked at 190°C and 0.5MPa for 15 minutes, and then cooled by liquid nitrogen at -20°C, with a cooling rate greater than 50°C, and finally granulated to obtain 1-2mm IL modified SEBS particles.

[0016] Furthermore, the polyether polyol includes a combination of different polyether polyols having NCO values ​​of 1%, 1.2%, and 1.4% in a volume ratio of 3:5:2.

[0017] Furthermore, the preparation method of the rigid foam polyurethane core material is:

[0018] S1. SEBS pellets were vacuum dried at 80°C for 4 h and then premixed with various polyether polyols at a mass ratio of 1:3. The mixture was melt-blended at 180-200°C under nitrogen for 15 min.

[0019] S2. Mix the pretreated SEBS / polyether mixture with the remaining polyether polyols, catalyst, water, and foam stabilizer at 70° C. for 10 min (1000 rpm);

[0020] S3. After mixing, place the mixture in an environment of 50°C and relative humidity <30% for 2 hours;

[0021] S4, add expandable graphite-silica fume composite and disperse at high speed at 1500 rpm and 75°C for 10 min;

[0022] S5, mixed with diphenylmethane diisocyanate (MDI) in a ratio of 1:1.4, then injected into the mold, foamed and cured at 45°C and 0.5MPa pressure for 30 minutes, and cut after aging to obtain the rigid foam polyurethane core material.

[0023] Furthermore, the polyether polyol includes a flexible base group and a rigid reinforcement group.

[0024] Furthermore, the rigidity enhancement group is a combination of medium NCO polyether + high NCO polyether; and the flexible matrix group is a combination of low NCO polyether + IL pretreated SEBS.

[0025] Furthermore, in step S1 , the flexible base group is mixed and then the rigid reinforcement group is added and mixed further.

[0026] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0027] First, the SEBS block copolymer includes styrene segments and ethylene-butylene segments, which can improve interfacial compatibility and enhance interfacial thermal stability; through the π-π interaction and hydrogen bond network of SEBS, the interfacial shear strength is increased, and the fracture toughness is optimized through the SEBS nanofiber network.

[0028] Second, ionic liquid-modified SEBS achieves cross-scale synergy through a multi-level dynamic bonding network. The π-cation bond provides high-strength anchoring and inhibits interface debonding; the dynamic cross-linking of ion clusters dissipates strain energy and improves fatigue life; the gradient buffer layer and the through-network synergistically deflect cracks.

[0029] Third, through the synergistic effect of polyether polyols with multi-level NCO values ​​and IL interface regulation, polarity matching and energy dissipation are achieved through multi-scale interactions such as chemical bonds (covalent / ion-dipole), hydrogen bond networks, and molecular chain orientation.

[0030] Fourth, the flexible matrix group reacts preferentially during low-speed mixing at 40°C to form a flexible continuous phase network: the EB segment of SEBS forms an interpenetrating network with the low-NCO polyether through hydrogen bonds, forming an energy dissipation skeleton; the imidazole cation of IL forms a dynamic ion-dipole bond with the polyether ether oxygen atom (-O-), providing a pre-crosslinking point; the flexible phase accounts for 60%-70%, covering the surface of the graphite particles to form a 5-10nm buffer layer; the rigidity enhancement group (medium / high NCO polyether) is dispersed under high-speed shear at 400rpm: the high-NCO polyether preferentially reacts with the hydroxyl groups on the graphite surface to form a covalent bond; the medium-NCO polyether forms an interfacial hydrogen bond network (bond density increased by 50%) with the unreacted -OH in the flexible phase through -NCO, bridging the two phases. DETAILED DESCRIPTION

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains; the terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0032] Example 1: A process for preparing a rigid foam polyurethane insulation board, comprising preparing a rigid foam polyurethane core material and compounding the core material with a vacuum protective surface layer.

[0033] The rigid polyurethane foam core material includes, by weight: 100 parts of various polyether polyols, 1 part of catalyst, 0.3 parts of water, 1 part of foam stabilizer, 3 parts of expandable graphite-microsilica powder composite, and 5-30 parts of SEBS modifier;

[0034] The multiple polyether polyols are: a rigid polyether polyol with a hydroxyl value of 360-390 mgKOH / g using glycerol as an initiator, a rigid polyether polyol with a hydroxyl value of 400-600 mgKOH / g using sorbitol as an initiator, and a rigid polyether polyol with a hydroxyl value of 250-500 mgKOH / g using propylene glycol as an initiator, and the weight ratio of the three is 1:1:1;

[0035] The preparation method of the expandable graphite-microsilica powder composite comprises the following steps: placing expandable graphite in xylene, ultrasonically dispersing the expandable graphite, adding microsilica powder, mixing the expandable graphite, filtering the solid matter, washing the solid matter, and drying the solid matter to obtain the composite. The weight ratio of the expandable graphite to the microsilica powder is 1:0.3.

[0036] The microsilica powder was also pre-treated: the microsilica powder was put into water, ultrasonically dispersed, silane coupling agent KH-550 was added, mixed evenly, filtered, washed, and dried to obtain the pre-treated microsilica powder;

[0037] The catalyst is a mixture of triethanolamine and dibutyltin dilaurate; the weight ratio of triethanolamine to dibutyltin dilaurate is 1:1;

[0038] SEBS modifier is a commonly used styrene-ethylene-butylene-styrene triblock copolymer; this embodiment uses YH-503T from Sinopec Hunan Petrochemical Co., Ltd.;

[0039] The preparation method of rigid foam polyurethane core material is as follows:

[0040] S1. SEBS pellets were vacuum dried at 80°C for 4 h and then premixed with various polyether polyols at a mass ratio of 1:3. The mixture was melt-blended at 180-200°C under nitrogen for 15 min.

[0041] S2. Mix the pretreated SEBS / polyether mixture with the remaining polyether polyols, catalyst, water, and foam stabilizer at 70° C. for 10 min (1000 rpm);

[0042] S3. After mixing, place the mixture in an environment of 50°C and relative humidity <30% for 2 hours;

[0043] S4, add expandable graphite-silica fume composite and disperse at high speed at 1500 rpm and 75°C for 10 min;

[0044] S5, mixed with diphenylmethane diisocyanate (MDI) in a ratio of 1:1.4, then injected into the mold, foamed and cured at 45°C and 0.5MPa pressure for 30 minutes, and cut after aging to obtain the rigid foam polyurethane core material.

[0045] The vacuum protective surface layer is a commonly used aluminum foil bag. In this embodiment, an aluminum foil bag produced by Kunshan Tonglida Packaging Materials Co., Ltd. is selected, and the thickness is 0.12 mm.

[0046] The core material and the vacuum protection surface layer are composited as follows: the rigid foam polyurethane core material is placed in an aluminum foil bag and vacuum-sealed to obtain the rigid foam polyurethane insulation board.

[0047] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0048] The SEBS block copolymer includes styrene segments and ethylene-butylene segments, which can improve interfacial compatibility and enhance interfacial thermal stability; through the π-π interaction and hydrogen bond network of SEBS, the interfacial shear strength is increased, and the fracture toughness is optimized through the SEBS nanofiber network.

[0049] The p orbital of the benzene ring in the styrene segment (PS) (ionization energy ≈ 9.2 eV) is similar to the sp 2 π-hybridized carbon * The orbitals (electron affinity ≈ 4.3 eV) form charge transfer complexes; the slip barrier generated by π-π stacking is reduced;

[0050] The C-H bond (bond energy 413 kJ / mol) of the butene chain in the ethylene-butene segment (EB) forms a dipole-inducing interaction with the NH of the urethane in the polyurethane hard segment (bond energy 391 kJ / mol);

[0051] The PS segment forms a 2-3 nm thick adsorption layer on the graphite surface, and the EB segment extends toward the polyurethane matrix, forming a gradient transition zone;

[0052] The PS / EB interface forms nanoscale "anchor points" (spacing about 20nm); PS microdomains (size 15-25nm) serve as physical crosslinking points, and the EB continuous phase forms energy dissipation channels. Through microphase separation regulation, not only the interfacial bonding ability is increased, but also the possibility of crack generation and growth is reduced. The formed energy dissipation channels can also reduce energy conduction, reduce heat transfer, and increase thermal insulation capacity.

[0053] When the crack propagation encounters the PS micro-area, it deflects. The EB phase absorbs energy through molecular chain slippage, increasing the toughness on the interface and preventing interface peeling that causes failure of the insulation board.

[0054] Through comparative experiments, the mechanism of action of SEBS block copolymer was verified, and performance tests were conducted on rigid polyurethane foam. The test methods are shown in Table 1, the results are shown in Table 2, and the key interface characterization data are shown in Table 3.

[0055] Table 1

[0056]

[0057]

[0058] Table 2

[0059]

[0060] Table 3

[0061]

[0062] Example 2: The above embodiment achieves dual chemical-physical anchoring of the interface, synergistic energy consumption of crack deflection and molecular chain slip, and decoupling of intercalation pre-setting and foaming process by adding SEBS modifier. However, in this application, it is applied to refrigerated trucks, mainly for transportation. Under different environments, the temperature changes greatly, and there is a difference in the thermal expansion coefficient of SEBS (CTE = 180ppm / ℃) and the polyurethane matrix (CTE = 80ppm / ℃). Experiments found that an interfacial strain of 0.8% was generated in a 48h cycle at -20℃-60℃ (DIC measurement), which was further improved on the basis of Example 1.

[0063] The SEBS modifier is also pretreated with an ionic liquid (IL). The pretreatment process is as follows: the ionic liquid is heated to 80°C, and after the viscosity is less than 50mPa·s, it is injected into SEBS that has been melted at 180°C in advance according to a weight ratio of IL / SEBS = 10%, and maintained at a shear rate of 600-800rpm for 5 minutes. Then, it is cross-linked at 190°C and 0.5MPa for 15 minutes, and then cooled by liquid nitrogen at -20°C with a cooling rate greater than 50°C. Finally, granulation is performed to obtain 1-2mm IL-modified SEBS particles.

[0064] In this embodiment, the ionic liquid (IL) is 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the addition amount is 0.5-3 parts by weight.

[0065] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0066] Ionic liquid modified SEBS achieves cross-scale synergy through a multi-level dynamic bonding network. The π-cation bond provides high-strength anchoring and inhibits interfacial debonding; the dynamic cross-linking of ion clusters dissipates strain energy and improves fatigue life; the gradient buffer layer and the through-network synergistically deflect cracks.

[0067] The coupling effect of π-cation electron cloud, imidazolium cation ([BMIM] + ) forms an electrostatic-π interaction with the π electron cloud of the benzene ring of the styrene (PS) segment of SEBS; the interaction energy is about 0.5-0.8 eV (between hydrogen bond and covalent bond);

[0068] Anion-flexible chain dipole interaction, ionic liquid anion (PF6 - ) forms an induced dipole interaction with the CH bond dipole of the SEBS ethylene-butylene (EB) segment; each PF6 - The binding energy with EB chain segment is about 5-10kJ / mol; when the temperature changes, PF6 -It can slide along the EB chain segment (activation energy is about 20kJ / mol) to achieve dynamic stress release.

[0069] Every 3-5 [BMIM][PF6] molecules form a 2-4 nm ion cluster through cation-anion stacking; the ion cluster is anchored on the benzene ring of the PS segment through electrostatic interaction, and at the same time through PF6 - The dipole interaction with the EB chain segments forms a cross-phase connection; the ion cluster acts as a dynamic crosslinking point and reversibly dissociates under strain; crack propagation requires the simultaneous destruction of the π-cation bond and the ion cluster (J integral from 28 to 42 kJ / m 2 ), which greatly increases the energy required for crack propagation.

[0070] A 5-10 nm thick ionic liquid-enriched layer forms on the surface of the PS micro-area; the proportion of π-cation bonds between imidazolium cations and benzene rings in the enriched layer is greater than 70% (Raman imaging statistics); thermal stress is gradient-transmitted through the enriched layer, and the crack propagation path is deflected by 55-70° in the enriched layer, reducing the degree of crack propagation and establishing a stress buffer layer;

[0071] The ion clusters and SEBS chain segments form a three-dimensional penetrating network; during temperature cycling, the ion clusters dissociate and absorb energy, and the strain energy is dissipated synergistically through ion slip and chain segment movement, utilizing the dynamic energy dissipation network to reduce stress accumulation.

[0072] The mechanism of action of IL was verified by experiments, and the final results were verified by experiments based on Experiment 2. The results and test standards are shown in Table 4;

[0073] Table 4

[0074]

[0075]

[0076] Example 3: Example 2 uses ionic liquid to modify SEBS to achieve cross-scale synergy through a multi-level dynamic bonding network. The π-cation bond provides high-strength anchoring and inhibits interface debonding; the ion clusters dynamically cross-link to dissipate strain energy and improve fatigue life; the gradient buffer layer and the through-network synergistically deflect cracks, but the mixing of multiple components often leads to polarity mismatch. The solubility gap between IL-modified SEBS and polyether polyol expandable graphite is quite large, which easily leads to local thermodynamic incompatibility. This is further improved on the basis of Example 2.

[0077] By controlling the amount of isocyanate used, polyether polyols with different NCO values ​​(molar ratio of NCO groups to hydroxyl groups) are obtained. The specific amount of diphenylmethane diisocyanate used is obtained by calculation;

[0078] The calculation process is:

[0079]

[0080] Among them, every 100g of diphenylmethane diisocyanate contains 0.8molNCO; the amount of diphenylmethane diisocyanate can be calculated.

[0081] A mixture of multiple polyether polyols including polyether polyols with NCO values ​​of 1%, 1.2%, and 1.4% is used in a volume ratio of 3:5:2.

[0082] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0083] Through the synergistic effect of polyether polyols with multi-level NCO values ​​and IL interface regulation, polarity matching and energy dissipation are achieved through multi-scale interactions such as chemical bonds (covalent / ion-dipole), hydrogen bond networks, and molecular chain orientation.

[0084] Low NCO polyether (δ=20MPa 1 / 2 ) is compatible with SEBS (δ=18), high NCO polyether (δ=22) bonds with graphite (δ=16) to form a polarity gradient interface, the low NCO group (1%) preferentially reacts with SEBS to form a flexible network, the high NCO group (1.2%) strengthens the bonding with graphite in the later stage, the -NCO of the medium NCO group (1.4%) polyether reacts with the -OH of graphite to form a chemical bond (bond energy 0.5eV), which offsets the polarity difference; at low temperatures, the low NCO component reacts to form a continuous phase, and at high temperatures, the high NCO component quickly cross-links and locks the graphite dispersion state, the low NCO component forms hydrogen bonds (bond energy 25kJ / mol), the medium and high NCO components construct a covalent network, and the multi-level bonds synergistically consume energy.

[0085] In polyether polyols with low NCO values, each polyether molecule contains one -NCO group, which preferentially reacts with the secondary amine group (-NH) of SEBS to form flexible urethane bonds (bond energy ≈ 350 kJ / mol) that wrap the graphite particles. In polyether polyols with high NCO values, excess -NCO can react with the hydroxyl groups (-OH) on the graphite surface to form covalent bonds (COC bond energy ≈ 460 kJ / mol), enhancing interfacial bonding and inhibiting agglomeration.

[0086] The unreacted -OH forms hydrogen bonds with the ether bonds (-O-) of SEBS (bond energy ≈ 25 kJ / mol), increasing the interface toughness. The excess -NCO forms intramolecular hydrogen bonds with the ether oxygen atoms of the polyether backbone (NH···OC, bond length ≈ 2.0 ), increasing the cross-linking density and ultimately obtaining a multi-scale cross-linked network, including: SEBS-NH and polyether-NCO forming a main valence bond to form a continuous phase skeleton; polyether-NCO and graphite-OH forming an interfacial bond to enhance stress transfer efficiency; hydrogen bonds between polyether molecules dissipate energy and improve dynamic fatigue performance.

[0087] The mechanism of action and results of different NCO polyether polyols were verified by experimental design. The experimental groups are shown in Table 5 and the results are shown in Table 6.

[0088] Table 5

[0089]

[0090]

[0091] Table 6

[0092]

[0093] Excess -NCO and IL anions (such as PF6 - ) forms ion-dipole interaction, which determines the interfacial binding energy and reaction activity; SEBS segment orientation and hydrogen bond network distribution control dynamic modulus fluctuations and energy dissipation efficiency; graphite sheet dispersion and phase interface gradient affect the continuity of the thermal conduction path.

[0094] Alternatively, various materials can be dissolved in a tetrahydrofuran solvent environment in step S1 in exchange for dispersion in a simpler environment (30°C, 300 rpm, 30 min), and THF is evaporated under reduced pressure (rate 0.5 mL / min) while gradually heating to 50°C (heating rate 2°C / min), maintaining a H2O content gradient (10→30%), so that the polarity difference of the hard segment / soft segment in the polyurethane forms an ordered interface through phase separation, and under a shear rate of 750 rpm, the dissociation of the entanglement points of the hyperbranched molecular chains is promoted to form nanochannels along the shear direction; a 2 kV / mm vertical electric field is applied externally to induce dipole orientation. Because the soft segment comes from polyether polyol and the hard segment comes from diphenylmethane diisocyanate (MDI), when the mass ratio of polyether polyol to MDI is 1:1, the most nanochannels are produced, which restrict the free path of gas molecular movement (from micron scale → nanoscale), the molecular chains at the nanochannel interface are highly ordered (SAXS shows orientation >85%), the phonon mean free path is from 50nm → 20nm, the inner wall of the nanochannel is composed of soft segments, which blocks the penetration of water molecules, and the closed porosity remains >90% after wet-heat aging, restricting the movement of gas molecules, enhancing phonon scattering, and the hard segments self-assemble to form a nano-reinforced phase. Crack expansion needs to bypass the ordered structure.

[0095] Example 4: Example 3 solves the problem of polarity mismatch in multi-component mixing by combining polyether polyols with different NCO values ​​or self-assembly of nanochannels. To further optimize the process of practical application, further improvements are made on the basis of Example 3.

[0096] The polyether polyols were grouped into the following groups: flexible matrix group: low NCO polyether + IL pretreated SEBS;

[0097] Rigidity enhancement group: medium NCO polyether + high NCO polyether;

[0098] In S1, the flexible matrix group was mixed (40° C., 200 rpm, 20 min) and then the rigid reinforcement group was added and continued to mix (400 rpm, 20 min).

[0099] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0100] The flexible matrix group preferentially reacts during low-speed mixing at 40°C to form a flexible continuous phase network: the EB segment of SEBS forms an interpenetrating network with the low-NCO polyether through hydrogen bonds, forming an energy dissipation skeleton; the imidazole cation of IL forms a dynamic ion-dipole bond with the polyether ether oxygen atom (-O-), providing a pre-crosslinking point; the flexible phase accounts for 60%-70%, covering the surface of the graphite particles to form a 5-10nm buffer layer; the rigidity enhancement group (medium / high NCO polyether) is dispersed under high-speed shear at 400rpm: the high-NCO polyether preferentially reacts with the hydroxyl groups on the graphite surface to form covalent bonds; the medium-NCO polyether forms an interfacial hydrogen bond network (bond density increased by 50%) with the unreacted -OH in the flexible phase through -NCO, bridging the two phases.

[0101] The IL-SEBS / low NCO polyether system forms a nanofiber network and dissipates energy through molecular chain slippage; the medium / high NCO polyether cross-links to form a 100-200nm island structure, which is anchored at the two-phase interface on the flexible network nodes through covalent bonds to form a 10-30nm gradient zone, and the NCO content gradually changes from 0.8% to 1.2%; matching memory differences.

[0102] The anion of IL (PF6 - ) forms ion-dipole bonds with excess -NCO in the rigid phase and reversibly dissociates under strain; the PS microregions of SEBS and high NCO polyether form physical cross-linking points through π-π stacking; the hydrogen bond network (bond energy 25kJ / mol) and covalent bonds (350-460kJ / mol) form multi-level energy dissipation paths.

[0103] The performance test of the core material prepared in Example 4 was carried out; the results are shown in Table 7;

[0104] Table 7

[0105]

[0106] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A process for preparing a rigid polyurethane foam insulation board, characterized in that: The method includes preparing a rigid foam polyurethane core material and compounding the core material with a vacuum protective surface layer; The rigid polyurethane foam core material includes, by weight: 100 parts of polyether polyol, 1 part of catalyst, 0.3 parts of water, 1 part of foam stabilizer, 3 parts of expandable graphite-microsilica powder composite, and 5-30 parts of SEBS modifier; The SEBS modifier is a styrene-ethylene-butylene-styrene triblock copolymer, and the SEBS modifier is an ionic liquid (IL) modified SEBS particle, the ionic liquid (IL) is 1-butyl-3-methylimidazolium hexafluorophosphate, and the addition amount is 0.5-3 parts by weight; The vacuum protection surface is an aluminum foil bag; The core material and the vacuum protection surface layer are composited as follows: the rigid foam polyurethane core material is placed in an aluminum foil bag and vacuum-sealed to obtain the rigid foam polyurethane insulation board.

2. The process for preparing a rigid polyurethane foam insulation board according to claim 1, wherein: The polyether polyols are hard polyether polyols with a hydroxyl value of 360-390 mgKOH / g using glycerol as an initiator, hard polyether polyols with a hydroxyl value of 400-600 mgKOH / g using sorbitol as an initiator, and hard polyether polyols with a hydroxyl value of 250-500 mgKOH / g using propylene glycol as an initiator, and the weight ratio of the three is 1:1:

1.

3. The process for preparing a rigid polyurethane foam insulation board according to claim 1, wherein: The preparation method of expandable graphite-microsilica powder composite is as follows: The expandable graphite is placed in xylene, ultrasonically dispersed, microsilica powder is added, mixed evenly, the solid matter is filtered and washed, and dried to obtain a composite. The weight ratio of the expandable graphite to the microsilica powder is 1:0.

3.

4. The process for preparing a rigid polyurethane foam insulation board according to claim 1, wherein: The catalyst is a mixture of triethanolamine and dibutyltin dilaurate; the weight ratio of triethanolamine to dibutyltin dilaurate is 1:

1.

5. The process for preparing a rigid polyurethane foam insulation board according to claim 1, wherein: The process of ionic liquid (IL) modified SEBS particles is as follows: the ionic liquid is heated to 80°C, and after the viscosity is less than 50mPa·s, it is injected into SEBS that has been melted at 180°C in advance according to the weight ratio of IL / SEBS = 10%, and maintained at a shear rate of 600-800rpm for 5 minutes. Then, it is cross-linked at 190°C and 0.5MPa for 15 minutes, and then cooled by liquid nitrogen at -20°C with a cooling rate greater than 50°C. Finally, granulation is performed to obtain IL-modified SEBS particles of 1-2mm.

6. The process for preparing a rigid foam polyurethane insulation board according to claim 1, wherein: The polyether polyol comprises a combination of different polyether polyols having NCO values ​​of 1%, 1.2% and 1.4% in a volume ratio of 3:5:

2.

7. The process for preparing a rigid polyurethane foam insulation board according to claim 1, wherein: The preparation method of rigid foam polyurethane core material is as follows: S1. SEBS pellets were vacuum dried at 80°C for 4 h and then premixed with various polyether polyols at a mass ratio of 1:

3. The mixture was melt-blended at 180-200°C under nitrogen for 15 min. S2. Mix the pretreated SEBS / polyether mixture with the remaining polyether polyols, catalyst, water, and foam stabilizer at 70° C. for 10 min (1000 rpm); S3. After mixing, place the mixture in an environment of 50°C and relative humidity <30% for 2 hours; S4, add expandable graphite-silica fume composite and disperse at high speed at 1500 rpm and 75°C for 10 min; S5, mixed with diphenylmethane diisocyanate (MDI) in a ratio of 1:1.4, then injected into the mold, foamed and cured at 45°C and 0.5MPa pressure for 30 minutes, and cut after aging to obtain the rigid foam polyurethane core material.

8. The process for preparing a rigid polyurethane foam insulation board according to claim 7, wherein: Polyether polyols include a flexible matrix group and a rigid reinforcement group.

9. The process for preparing a rigid polyurethane foam insulation board according to claim 8, characterized in that: The rigidity enhancement group is a combination of medium NCO polyether + high NCO polyether; the flexible matrix group is a combination of low NCO polyether + IL pretreated SEBS.

10. The process for preparing a rigid polyurethane foam insulation board according to claim 9, characterized in that: In step S1, the flexible base group is mixed and then the rigid reinforcement group is added and mixed.

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