Cement foaming fireproof door core double-sided composite board and preparation method thereof

Abstract

According to the cement foaming fireproof door core double-sided composite board and the preparation method thereof, by adding the modified phase change energy storage material with the microcapsule structure, packaging of a lithium nitrate / potassium nitrate composite phase change material is achieved, and the bonding strength, the breaking strength and the fire resistance and heat insulation performance of a cement foaming fireproof door core board are remarkably improved; the modified phase change energy storage material is provided with a silicon dioxide loaded lithium nitrate-potassium nitrate composite phase change material core material, a polyacrylate middle layer and a polyurethane shell layer.

Description

Technical Field

[0001] This invention belongs to the field of fireproof door panels, specifically relating to a double-sided composite board with a cement foamed fireproof door core and its preparation method. Background Technology

[0002] Fire doors possess multiple functions and practicalities, including sealing, fire resistance, partitioning, safety, heat insulation, and sound insulation, making them an indispensable component of buildings. Foamed cement fire door core boards dominate the market. Current technologies for foamed cement fire door core boards are divided into physical foaming and chemical foaming. Physical foaming involves pressurizing a cement foaming agent using a foaming machine to form foam with a certain tension. This foam is then mixed with cement slurry and fibers. Once the expansion reaches a pre-set ratio, it is poured into a mold for shaping. Chemical foaming typically uses hydrogen peroxide as the foaming agent, mixed with a suitable foam stabilizer and PP fibers, and then poured into a mold. The foaming is achieved using the gas generated by the decomposition of hydrogen peroxide. After foaming, the core boards are cured for 5-7 days and then cut to the required size and thickness. Chemically foamed core boards generally come in two types: one type is directly filled into the fire door after cutting, and the other type is filled into the fire door after non-woven fabric is pasted on both sides.

[0003] Physically foamed fireproof door cores suffer from problems such as small cell size and thin cell walls, leading to low strength and easy powdering. Chemically foamed cores, directly cut and filled into fireproof doors, have three drawbacks: ① insufficient cutting precision; ② poor adhesion to the fireproof door steel plate, causing internal detachment and powdering after significant vibration; ③ due to the exposed cell size, a large amount of adhesive is required for bonding. The solution of bonding non-woven fabric to chemically foamed core panels solves the adhesion problem caused by insufficient cutting precision by bonding flexible material (non-woven fabric) on both sides, but still suffers from poor adhesion and high adhesive consumption. The aforementioned chemically foamed products can only be manufactured in small pieces, resulting in many gaps when spliced ​​inside fireproof doors, severely affecting their fire resistance.

[0004] On the other hand, when exposed to high temperatures, the non-uniform heat conduction of foamed cement fireproof door core boards can easily cause cracks, thus affecting the fire resistance and heat insulation performance of the fire door. To improve the fire resistance and heat insulation performance of fire doors, fire-retardant coatings are typically applied to the foamed cement fireproof door core boards. However, this only provides short-term relief. As cracks appear and expand in the fireproof door core board, the fire-retardant coating will further crack and even peel off, resulting in a significant decrease in the fire door's heat insulation performance. Summary of the Invention

[0005] To overcome the problems existing in the prior art, the present invention aims to provide a double-sided composite board for foamed cement fireproof door cores. By adding a modified phase change energy storage material with a microcapsule structure, the lithium nitrate / potassium nitrate composite phase change material is encapsulated, which significantly improves the bonding strength, flexural strength and fire resistance and heat insulation of the foamed cement fireproof door core board. The modified phase change energy storage material has a silica-supported lithium nitrate-potassium nitrate composite phase change material core, a polyacrylate intermediate layer, and a polyurethane shell.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A double-sided composite board for fireproof door cores made of foamed cement, characterized in that it comprises 100-160 parts of silicate cement, 2-5 parts of quartz sand, 2-6 parts of modified phase change energy storage material, 25-65 parts of water, 0.1-0.4 parts of calcium stearate, 0.1-0.55 parts of PP fiber, 2-5 parts of wollastonite, 2-3 parts of foaming agent, and 0.3-0.6 parts of foam stabilizer.

[0007] The modified phase change energy storage material has a silica-supported lithium nitrate-potassium nitrate composite phase change material core, a polyacrylate intermediate layer, and a polyurethane shell.

[0008] The foaming agent is at least one of the following: animal foaming agent, plant foaming agent, sodium rosinate, high foaming agent, LG-2258, and hydrogen peroxide.

[0009] The modified phase change energy storage material has a microcapsule structure, and its preparation method is as follows: Step 1: Dissolve lithium nitrate and potassium nitrate in distilled water at a mass-to-volume ratio of 1:50-200 g / mL, stir until the solution is clear, slowly add the resulting mixture dropwise to silicon tetrachloride at a volume of 5-15% of the distilled water, let stand for 30 min, dry at 80℃ for 70 h, cool, grind, and sieve to obtain silica-supported phase change energy storage material A with a particle size of 5-10 μm; Step 2: The phase change energy storage material A obtained in Step 1 is pretreated with a silane coupling agent to obtain a surface-modified phase change energy storage material A. Step 3: Mix 1-10 parts of acrylic hard monomer, 5-30 parts of long-chain alkyl acrylate, 1-5 parts of quaternary ammonium salt acrylate, 1-3 parts of crosslinking agent, 1-5 parts of emulsifier and 50-150 parts of deionized water in sequence and stir until uniformly dispersed to prepare a pre-emulsion. Step 4: Mix 1 / 3 of the pre-emulsion with the surface-modified phase change energy storage material A obtained in Step 2, and sonicate for 5-30 minutes to obtain the seed pre-emulsion; Step 5: Add the seed pre-emulsion obtained in Step 4, 1-3 parts of emulsifier, 0.1-2 parts of initiator and 50-100 parts of deionized water to the reactor, start stirring, heat to 35-85℃, and react for 10-65 minutes to obtain the seed emulsion. Step 6: Next, add the remaining pre-emulsion and 5-30 parts of hydroxy acrylate dropwise to the reactor simultaneously, completing the dropwise addition within 1-2 hours. Then, add 0.1-1 parts of redox initiator, continue to keep warm for 1-3 hours, cool down, filter, and obtain phase change energy storage material B. Step 7: Mix 1-30 parts of isocyanate, 1-20 parts of polyester polyol, 1-6 parts of chain extender, 1-6 parts of phase change energy storage material B, and 0.1-1 parts of catalyst to obtain a modified phase change energy storage material with a microcapsule structure.

[0010] Preferably, the molar ratio of the phase change material lithium nitrate to potassium nitrate is 1:1-3.

[0011] Preferably, the molar ratio of the phase change material lithium nitrate to potassium nitrate is 4:6.

[0012] Preferably, the silane coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and vinyl(2-methoxydiethoxy)silane.

[0013] Preferably, the acrylic hard monomer is one or more selected from methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl methacrylate, and styrene.

[0014] Preferably, the long-chain alkyl acrylate is one or more of isooctyl acrylate, dodecyl acrylate, hexadecyl acrylate, and octadecyl acrylate.

[0015] Preferably, the quaternary ammonium acrylate is one or more of (meth)acryloyloxyethyltrimethylammonium chloride and (meth)acryloyloxypropyltrimethylammonium chloride.

[0016] Preferably, the mass ratio of the acrylic hard monomer, the long-chain alkyl acrylate, and the quaternary ammonium acrylate is 1:2-15:1-5.

[0017] Preferably, the crosslinking agent is one or more of N,N'-methylenebisacrylamide, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipropylene glycol diacrylate, and diacetone acrylamide.

[0018] Preferably, the emulsifier is one or more of hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, polyvinyl alcohol, Tween, and Span.

[0019] Preferably, the initiator is one or more of KPS, APS, BPO, AIBN, AIVN, and redox initiators.

[0020] Preferably, the isocyanate is one or more selected from isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, phenylene dimethyl diisocyanate, 1,4-cyclohexane diisocyanate, and polyphenylmethane polyisocyanate.

[0021] Preferably, the polyester polyol is a polyester diol prepared by adipic acid with 1,4-butanediol, 1,6-hexanediol or ethylene glycol, having a hydroxyl value of 160-220 mgKOH / g, a functionality of 2-4, and an average molecular weight of 1000-4000.

[0022] Preferably, the catalyst is one or more of dimethylcyclohexylamine, triethyldiamine, pentamethyldiethyltriamine, dibutyltin dilaurate, and dibutyltin diacetate.

[0023] Preferably, the chain extender is one or more selected from ethylene glycol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol and 1,5-pentanediol.

[0024] A method for preparing a double-sided composite board with foamed cement fireproof door core, specifically including the following steps: According to the composition of the cement foamed fireproof door core double-sided composite board, weigh the raw materials, add each raw material to the mixing tank and stir at 100-300r / min for 5-30min. Then pour it into the mold. The upper and lower layers of the mold are lined with alkali-free fiber cloth. Cure for 10-15h at a temperature of 20-25℃ and a relative humidity of 85-90%. After demolding, continue curing for 15-20 days. Use a reciprocating saw to slice to obtain the cement foamed fireproof door core double-sided composite board.

[0025] The beneficial effects of this invention are as follows: 1) The double-sided composite board for foamed cement fireproof door cores of this invention uses modified phase change energy storage materials. The core material is a silica-supported lithium nitrate / potassium nitrate composite phase change material generated in situ. A polyacrylate intermediate layer is formed by pre-emulsification seed emulsion polymerization. The surface hydroxyl groups of the polyacrylate intermediate layer react with isocyanates to form a polyurethane shell, resulting in a modified phase change energy storage material with a microcapsule structure. This encapsulates the lithium nitrate / potassium nitrate composite phase change material, enabling the double-sided composite board for foamed cement fireproof door cores to eliminate temperature differences in the core board at high temperatures. This reduces the thermal stress caused by the non-uniformity of heat conduction in the core board, thereby improving the cracking phenomenon of the core board and enhancing its fire resistance.

[0026] 2) The modified phase change energy storage material of the present invention has a microcapsule structure. The introduction of polyacrylate intermediate layer and polyurethane shell layer not only gives the modified phase change energy storage material a microcapsule structure, but also the flexibility of resin, which can improve the compressive strength and flexural strength of the core plate.

[0027] 3) In the modified phase change energy storage material with microcapsule structure of the present invention, the polyacrylate intermediate layer simultaneously adopts long-chain alkyl acrylate and quaternary ammonium salt acrylate functional monomers, which not only improves the impact resistance and flexibility of the microcapsule structure, but also improves the adhesion to the substrate. In addition, the quaternary ammonium salt acrylate functional monomers can improve the high temperature resistance. The two play a synergistic role, further improving the phase change energy storage effect of the composite phase change material and improving the flame resistance, thereby improving the compressive strength, flexural strength and flame resistance of the cement foam fireproof door core double-sided composite board. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention will be further explained and described below with reference to specific embodiments.

[0029] Preparation Example 1 The modified phase change energy storage material has a microcapsule structure, and its preparation method is as follows: Step 1: Dissolve lithium nitrate and potassium nitrate in distilled water at a mass-to-volume ratio of 1:150 g / mL, stir until the solution is clear, slowly add the resulting mixture dropwise to silicon tetrachloride at 12% of the volume of distilled water, let stand for 30 min, dry at 80℃ for 70 h, cool, grind, and sieve to obtain silica-supported phase change energy storage material A with a particle size of 6 μm; the molar ratio of lithium nitrate to potassium nitrate in the phase change material is 2:3. Step 2: The phase change energy storage material A obtained in Step 1 is pretreated with vinyltrimethoxysilane to obtain a surface-modified phase change energy storage material A. Step 3: Mix 6 parts styrene, 20 parts dodecyl acrylate, 6 parts acryloyloxyethyltrimethylammonium chloride, 1 part trimethylolpropane triacrylate, 1 part sodium dodecyl sulfate and 100 parts deionized water in sequence and stir until uniformly dispersed to prepare a pre-emulsion. Step 4: Mix 1 / 3 of the pre-emulsion with 10 parts of the surface-modified phase change energy storage material A obtained in Step 2, and sonicate for 10 minutes to obtain the seed pre-emulsion. Step 5: Add the seed pre-emulsion obtained in Step 4, 1 part of sodium dodecyl sulfate, 0.2 parts of initiator KPS and 100 parts of deionized water to the reactor, turn on the stirring, heat to 35°C, and react for 35 min to obtain the seed emulsion. Step 6: Next, add the remaining pre-emulsion and 8 parts of hydroxyethyl methacrylate dropwise to the reactor simultaneously, completing the addition within 2 hours. Then, add 0.1 parts of redox initiator, continue to keep warm for 2 hours, cool down, filter, and obtain phase change energy storage material B. Step 7: Mix 18 parts of isophorone diisocyanate, 10 parts of polyester polyol, 2 parts of 1,4-butanediol, 3 parts of phase change energy storage material B, and 0.1 parts of catalyst dibutyltin dilaurate to obtain a modified phase change energy storage material with a microcapsule structure. The polyester polyol is a polyester polyol with a hydroxyl value of 200 mg KOH / g, a functionality of 3, and an average molecular weight of 2000.

[0030] Preparation Example 2 Modified phase change energy storage materials have a microcapsule structure: Prepared according to the method of Preparation Example 1, the only difference being that in step 3, dodecyl acrylate is replaced with acryloyloxyethyltrimethylammonium chloride.

[0031] Preparation Example 3 Modified phase change energy storage materials have a microcapsule structure: The preparation method is the same as in Example 1, except that in step 2, vinyltrimethoxysilane is replaced with hydroxyethylmethyldimethoxysilane to obtain surface-modified phase change energy storage material A, while steps 3-6 are omitted.

[0032] Preparation Example 4 Modified phase change energy storage materials: Prepared according to the method of Preparation Example 1, the only difference being that steps 2-7 are omitted.

[0033] Example 1 The raw materials for the cement foamed fireproof door core double-sided composite board include 120 parts of silicate cement, 3 parts of quartz sand, 5 parts of the modified phase change energy storage material prepared in Preparation Example 1, 45 parts of water, 0.3 parts of calcium stearate, 0.4 parts of PP fiber, 3 parts of wollastonite, 2 parts of foaming agent sodium rosinate, and 0.3 parts of foam stabilizer sodium dodecylbenzene sulfonate.

[0034] A method for preparing a double-sided composite board with foamed cement fireproof door core involves weighing raw materials according to the composition of the foamed cement fireproof door core double-sided composite board, adding each raw material to a mixing tank and stirring at 200 r / min for 10 min, then pouring it into a mold. The upper and lower layers of the mold are lined with alkali-free fiber cloth. The mold is cured for 12 h at a temperature of 25℃ and a relative humidity of 90%. After demolding, the mold is cured for another 18 days. The board is then sliced ​​using a reciprocating saw to obtain the foamed cement fireproof door core double-sided composite board.

[0035] Example 2 A double-sided composite board for foamed cement fireproof door core is prepared according to the method of Example 1, the only difference being that the modified phase change energy storage material prepared in Example 1 is replaced with the modified phase change energy storage material prepared in Example 2.

[0036] Example 3 A double-sided composite board for foamed cement fireproof door core is prepared according to the method of Example 1, the only difference being that the modified phase change energy storage material prepared in Example 1 is replaced with the modified phase change energy storage material prepared in Example 3.

[0037] Comparative Example 1 A double-sided composite board for foamed cement fireproof door core is prepared according to the method of Example 1, the only difference being that the modified phase change energy storage material prepared in Example 1 is replaced with the modified phase change energy storage material prepared in Example 4.

[0038] The performance of the cement foamed fireproof door core double-sided composite panels obtained in Examples 1-3 and Comparative Example 1 was characterized: Compressive strength and flexural strength: Mechanical properties were determined according to GB / T 11971-2022 "Test Methods for Mechanical Properties of Aerated Concrete".

[0039] Flame resistance performance: according to GB 8624 The 2012 "Classification of Combustion Performance of Building Materials and Products" determines the combustion performance rating.

[0040] Table 1 Performance of Cement Foamed Fireproof Door Core Double-Sided Composite Board

[0041] As can be seen from the comparison between Example 1 and Comparative Example 1, the cement foamed fireproof door core double-sided composite board prepared in Example 1 of the present invention has better performance in terms of compressive strength, flexural strength and fire resistance. This may be because Example 1 uses a modified phase change energy storage material with a microcapsule structure. The modified phase change energy storage material has a microcapsule structure. The core material is a silica-supported lithium nitrate / potassium nitrate composite phase change material generated in situ. A polyacrylate intermediate layer is formed by pre-emulsification seed emulsion polymerization. The surface hydroxyl groups of the polyacrylate intermediate layer react with isocyanate and other substances to form a polyurethane shell layer, thus obtaining a modified phase change energy storage material with a microcapsule structure. This achieves the encapsulation of the lithium nitrate / potassium nitrate composite phase change material, which enables the cement foamed fireproof door core double-sided composite board to eliminate the temperature difference in the core board at high temperatures. This reduces the thermal stress caused by the non-uniformity of heat conduction in the core board, thereby improving the phenomenon of easy cracking of the core board and improving the fire resistance. Meanwhile, compared with Comparative Example 1, which only uses in-situ generated silica-supported lithium nitrate / potassium nitrate composite phase change material, the modified phase change energy storage material of Example 1 of this invention further includes a polyacrylate interlayer and a polyurethane shell. The polyurethane shell can further improve the flame retardant performance, and the quaternary ammonium salt acrylate monomer acryloyloxyethyltrimethylammonium chloride in the polyacrylate interlayer can further improve the high temperature resistance, thereby achieving a further improvement in flame resistance. Furthermore, the introduction of the polyacrylate interlayer and the polyurethane shell gives the modified phase change energy storage material both a microcapsule structure and the flexibility of resin, which can improve the compressive strength and flexural strength of the core board.

[0042] A comparison of Examples 1, 2, and 3 shows that the cement-foamed fireproof door core double-sided composite board prepared in Example 1 of this invention exhibits superior overall performance in terms of compressive strength, flexural strength, and fire resistance. This may be because the polyacrylate intermediate layer of the modified phase change energy storage material in Example 1 simultaneously uses dodecyl acrylate and acryloyloxyethyltrimethylammonium chloride. The long-chain acrylate monomers can further improve the impact resistance and flexibility of the microcapsule structure, and also improve the adhesion to the substrate by reducing the Tg of the polyacrylate. The long-chain alkyl acrylate and quaternary ammonium salt acrylate functional monomers... Peroxy group and quaternary ammonium cationic group can not only improve the crosslinking degree of the three-dimensional structure of the resin, but also improve the adhesion to the substrate through the polar interaction force with other polar groups. Acryloyloxyethyltrimethylammonium chloride is a high-temperature resistant modifying monomer. All of the above effects can further improve the phase change energy storage effect of the composite phase change material, reduce the thermal stress caused by the non-uniformity of heat conduction in the core board, thereby improving the phenomenon of easy cracking of the core board and improving the flame resistance. The functional monomers of long-chain alkyl acrylate and quaternary ammonium salt acrylate play a synergistic role, thereby improving the compressive strength, flexural strength and flame resistance of the cement foam fireproof door core double-sided composite board.

[0043] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A double-sided composite board for a cement-foamed fireproof door core, characterized in that, The mixture comprises 100-160 parts silicate cement, 2-5 parts quartz sand, 2-6 parts modified phase change energy storage material, 25-65 parts water, 0.1-0.4 parts calcium stearate, 0.1-0.55 parts PP fiber, 2-5 parts wollastonite, 2-3 parts foaming agent, and 0.3-0.6 parts foam stabilizer. The modified phase change energy storage material has a silica-supported lithium nitrate-potassium nitrate composite phase change material core, a polyacrylate intermediate layer, and a polyurethane shell.

2. The double-sided composite board for foamed cement fireproof door cores according to claim 1, characterized in that: The modified phase change energy storage material has a microcapsule structure, and its preparation method is as follows: Step 1: Dissolve lithium nitrate and potassium nitrate in distilled water at a mass-to-volume ratio of 1:50-200 g / mL, stir until the solution is clear, slowly add the resulting mixture dropwise to silicon tetrachloride at a volume of 5-15% of the distilled water, let stand for 30 min, dry at 80℃ for 70 h, cool, grind, and sieve to obtain silica-supported phase change energy storage material A with a particle size of 5-10 μm; Step 2: The phase change energy storage material A obtained in Step 1 is pretreated with a silane coupling agent to obtain a surface-modified phase change energy storage material A. Step 3: Mix 1-10 parts of acrylic hard monomer, 5-30 parts of long-chain alkyl acrylate, 1-5 parts of quaternary ammonium salt acrylate, 1-3 parts of crosslinking agent, 1-5 parts of emulsifier and 50-150 parts of deionized water in sequence and stir until uniformly dispersed to prepare a pre-emulsion. Step 4: Mix 1 / 3 of the pre-emulsion with the surface-modified phase change energy storage material A obtained in Step 2, and sonicate for 5-30 minutes to obtain the seed pre-emulsion; Step 5: Add the seed pre-emulsion obtained in Step 4, 1-3 parts of emulsifier, 0.1-2 parts of initiator and 50-100 parts of deionized water to the reactor, start stirring, heat to 35-85℃, and react for 10-65 minutes to obtain the seed emulsion. Step 6: Next, add the remaining pre-emulsion and 5-30 parts of hydroxy acrylate dropwise to the reactor simultaneously, completing the dropwise addition within 1-2 hours. Then, add 0.1-1 parts of redox initiator, continue to keep warm for 1-3 hours, cool down, filter, and obtain phase change energy storage material B. Step 7: Mix 1-30 parts of isocyanate, 1-20 parts of polyester polyol, 1-6 parts of chain extender, 1-6 parts of phase change energy storage material B, and 0.1-1 parts of catalyst to obtain a modified phase change energy storage material with a microcapsule structure.

3. The double-sided composite board for foamed cement fireproof door cores according to claim 1, characterized in that: The molar ratio of the phase change material lithium nitrate and potassium nitrate is 1:1-3.

4. The double-sided composite board for foamed cement fireproof door cores according to claim 3, characterized in that: The long-chain alkyl acrylate is one or more of isooctyl acrylate, dodecyl acrylate, hexadecyl acrylate, and octadecyl acrylate.

5. The double-sided composite board for foamed cement fireproof door cores according to claim 1, characterized in that: The quaternary ammonium acrylate is one or more of (meth)acryloyloxyethyltrimethylammonium chloride and (meth)acryloyloxypropyltrimethylammonium chloride.

6. The double-sided composite board for foamed cement fireproof door cores according to claim 1, characterized in that: The mass ratio of the acrylic hard monomer, the long-chain alkyl acrylate, and the quaternary ammonium salt acrylate is 1:2-15:1-5.

7. The double-sided composite board for foamed cement fireproof door cores according to claim 1, characterized in that: The silane coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and vinyl(2-methoxydiethoxy)silane.

8. According to claim 1 The method for preparing the cement foam fireproof door core double-sided composite board according to any one of the following claims is characterized in that, Includes the following steps: According to claim 1 7. The composition of the cement foamed fireproof door core double-sided composite board as described in any one of the claims is as follows: weigh the raw materials, add each raw material to a mixing tank and stir and mix at 100-300 r / min for 5-30 min, then pour into a mold, the upper and lower layers of the mold are arranged with alkali-free fiber cloth, and cure for 10-15 h at a temperature of 20-25℃ and a relative humidity of 85-90%. After demolding, continue to cure for 15-20 days, and use a reciprocating saw to slice to obtain the cement foamed fireproof door core double-sided composite board.

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