Straw soil building block for ribbed sandwich panel and preparation method of straw soil building block

Abstract

The invention relates to the field of building materials, in particular to a straw soil building block for a dense rib sandwich panel and a preparation method of the straw soil building block. The straw soil building block is prepared from the following raw materials: 30 to 40 parts of clay, 15 to 25 parts of cement, 10 to 15 parts of desulfurized gypsum powder, 5 to 10 parts of epoxy resin emulsion, 2 to 4 parts of hyperbranched polyurethane acrylate emulsion, 0.5 to 1 part of hydrogen-containing polysiloxane modified allyl epoxy resin, 1 to 3 parts of organic amine, 10 to 15 parts of straw fiber, 0.1 to 1 part of polycarboxylate superplasticizer and 20 to 40 parts of water. The straw soil building block prepared by the invention has excellent mechanical properties and heat insulation and heat preservation properties, is low in water absorption rate, and is an ideal core material of a multi-ribbed sandwich panel.

Description

Technical Field

[0001] The invention relates to the field of building materials, in particular to a straw-soil building block for a multi-rib sandwich panel and a preparation method thereof. Background Art

[0002] As a new type of building structure system, the multi-rib sandwich panel building structure can effectively reduce the amount of building materials, increase the construction speed, improve the self-insulation effect of the building, and reduce energy consumption. In terms of application scenarios, it is widely used in various building components such as walls, roofs, partitions, etc., and is suitable for various scenarios such as industrial plants, commercial buildings, residences and stadiums, showing great flexibility and applicability.

[0003] Straw-soil blocks are high-performance building materials made from plant straw and soil through compression molding. They not only have good thermal insulation properties, but also can turn waste into treasure and realize resource recycling. How to improve the mechanical properties and thermal insulation properties of straw-soil blocks so that they can be used as core materials for dense-rib sandwich panels has become a current research hotspot. Summary of the invention

[0004] Purpose of the invention: In view of the above technical problems, the present invention proposes a straw-soil block for multi-rib sandwich panels and a preparation method thereof.

[0005] The technical solutions adopted are as follows:

[0006] A straw-soil block for a dense-rib sandwich panel is prepared from the following raw materials in parts by weight:

[0007] 30-40 parts of clay, 15-25 parts of cement, 10-15 parts of desulfurized gypsum powder, 5-10 parts of epoxy resin emulsion, 2-4 parts of hyperbranched polyurethane acrylate emulsion, 0.5-1 parts of hydrogenated polysiloxane-modified allyl epoxy resin, 1-3 parts of organic amine, 10-15 parts of straw fiber, 0.1-1 parts of polycarboxylic acid water reducer and 20-40 parts of water.

[0008] Furthermore, the clay is modified by a silane coupling agent.

[0009] Furthermore, the preparation method of the clay is as follows:

[0010] The nanoclay is dispersed in an ethanol aqueous solution to obtain a dispersion, a silane coupling agent is added to the ethanol aqueous solution and stirred in a 40-60° C. water bath for 30-60 minutes, and then the dispersion is added, and the reaction is kept warm for 10-20 hours, followed by centrifugation, and the precipitate is collected, washed, and dried.

[0011] Furthermore, the silane coupling agent is KH-560.

[0012] Further, the preparation method of the hyperbranched polyurethane acrylate emulsion is as follows:

[0013] The polytetrahydrofuran and dimethylol propionic acid are mixed and heated to 55-65° C., 4,4'-dicyclohexylmethane diisocyanate and an organic tin catalyst are added dropwise under stirring, and the mixture is stirred for reaction for 30-60 minutes after the addition is completed. The mixture is heated to 75-85° C. and the reaction is continued for 1-5 hours. Hydroxyethyl acrylate is added and the reaction is continued for 1-5 hours. Pentaerythritol triacrylate is added and the reaction is continued for 1-5 hours. Terminal hydroxyl hyperbranched polyester is added and the reaction is continued for 1-5 hours. The mixture is cooled to 40-60° C., triethylamine is added and the reaction is continued for 30-60 minutes. The mixture is then restored to room temperature. Deionized water is added under strong stirring for emulsification to obtain the hyperbranched polyurethane acrylate emulsion.

[0014] Furthermore, the organic tin catalyst is a metal organic compound formed by direct combination of tin and carbon elements, preferably dibutyltin dilaurate.

[0015] Furthermore, the preparation method of the hydrogen-containing polysiloxane-modified allyl epoxy resin is as follows:

[0016] Add chloroplatinic acid to hydrogen-containing polysiloxane, stir and heat to 80-100°C, then slowly add allyl epoxy resin, keep warm and react for 5-10 hours after the addition, and finally remove low-boiling substances by distillation under reduced pressure.

[0017] Furthermore, the mass ratio of the hydrogen-containing polysiloxane to the allyl epoxy resin is 1:0.5-1.

[0018] Further, the organic amine is a combination of triethanolamine and ethylenediamine;

[0019] The mass ratio of triethanolamine to ethylenediamine is 1-5:1-5.

[0020] Furthermore, the preparation method of the straw fiber is as follows:

[0021] Cut the crop straw into sections, soak them in a sodium hydroxide solution with a mass concentration of 5-10wt% and a temperature of 40-60°C for 1-10 hours, filter them, wash them with water until they are neutral, and then dry them.

[0022] Furthermore, the crop straw is preferably cereal crops, specifically rice straw, wheat straw, corn straw, barley straw, oat straw, sorghum straw, millet straw, and millet straw.

[0023] Furthermore, the crop straw is preferably wheat straw.

[0024] The present invention also provides a method for preparing straw soil blocks for multi-rib sandwich panels:

[0025] Clay, cement, desulfurized gypsum powder and straw fiber are pre-mixed to obtain a solid material, polycarboxylic acid water reducer is dissolved in water and added to the solid material and stirred evenly, epoxy resin emulsion, hyperbranched polyurethane acrylate emulsion and hydrogenated polysiloxane modified allyl epoxy resin are then added and stirred continuously, finally organic amine is added and poured into a mold for cold pressing, demolding is performed after steam curing, and then the material is placed in a dark and ventilated place to the corresponding age.

[0026] Beneficial effects of the present invention:

[0027] The invention provides a straw-soil block for a multi-rib sandwich panel. Clay is a kind of soil, and its main mineral components are kaolinite, illite and montmorillonite. The addition of clay can promote the hydration of cement to generate hydrated calcium silicate, hydrated calcium aluminate, garnet, amorphous gel and Ca(OH) 2 These hydration products increase the density of the gelled crystal network structure, thereby improving the mechanical strength of the straw-soil block and reducing the water absorption rate. After being modified by the silane coupling agent KH-560, the silanol group reacts with the hydroxyl group on the clay surface to introduce epoxy groups on the clay surface. The epoxy groups can enter the polymer film through the cross-linking reaction of chemical bonds, thereby increasing the bonding strength of the clay in the straw-soil block, thereby further improving the performance of the straw-soil block.

[0028] Epoxy resin emulsion and hyperbranched polyurethane acrylate emulsion can form an interpenetrating polymer network, which can inhibit the generation of microcracks, improve the internal pore structure, play a role in heat insulation and fixed support, and make the structure of the straw soil block more compact. The contained hyperbranched polyhydroxy structure not only improves the compatibility of polyurethane acrylate emulsion and epoxy resin emulsion, but also the contained hydroxyl groups can promote the curing of epoxy resin emulsion, increase the crosslinking density of the interpenetrating polymer network, so that it can absorb impact energy from all directions, and can play a better resistance role when subjected to external force impact, thereby improving the compressive and flexural properties of the straw soil block.

[0029] The hydrogenated polysiloxane-modified allyl epoxy resin can not only participate in the cross-linking of epoxy resin emulsion and hyperbranched polyurethane acrylate emulsion to form a hydrophobic network structure, but also form a microstructure inside the straw-soil block to inhibit shrinkage and cracking, making it more compact and firm, thereby improving the strength and durability of the straw-soil block and improving its waterproof and anti-seepage capabilities.

[0030] The addition of straw fiber causes large air bubbles in the mixing process to be divided into closed small bubbles by the fibers. The closed small bubbles can effectively prevent heat transfer, thereby reducing the thermal conductivity of the sample and improving the thermal insulation performance. In addition, the internal porosity of straw fiber is relatively large, and it is a low thermal conductivity material, which can also improve the thermal insulation performance. Straw soil blocks are prone to shrinkage during the maintenance and drying process, which leads to the formation of cracks. The addition of straw fiber can increase the internal skeleton structure, reduce the shrinkage, and thus reduce the cracking tendency. The straw soil blocks prepared by the present invention have excellent mechanical properties and thermal insulation properties, and low water absorption, and are ideal core materials for dense-rib sandwich panels. DETAILED DESCRIPTION

[0031] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0032] Clay: homemade;

[0033] Cement: PO 42.5 ordinary Portland cement, Conch;

[0034] Desulfurized gypsum powder: 200-325 mesh, purchased from Xinxiang Bafang Calcium Industry Co., Ltd.;

[0035] Epoxy resin emulsion: solid content 60%, Sheng Wanjia;

[0036] Hyperbranched polyurethane acrylate emulsion: homemade;

[0037] Hydrogenated polysiloxane-modified allyl epoxy resin: homemade;

[0038] Triethanolamine: purchased from Jinan Shunwang Chemical Co., Ltd.

[0039] Ethylenediamine: purchased from Jinan Shunwang Chemical Co., Ltd.

[0040] Straw fiber: homemade;

[0041] Polycarboxylate water reducer: PC-412, Hengda;

[0042] Water: tap water.

[0043] Embodiment 1:

[0044] A straw-soil block for a dense-rib sandwich panel is prepared from the following raw materials in parts by weight:

[0045] 35 parts of clay, 20 parts of cement, 12 parts of desulfurized gypsum powder, 8 parts of epoxy resin emulsion, 3 parts of hyperbranched polyurethane acrylate emulsion, 1 part of hydrogenated polysiloxane-modified allyl epoxy resin, 1 part of triethanolamine, 1 part of ethylenediamine, 12 parts of straw fiber, 0.5 part of polycarboxylic acid water reducer, and 30 parts of water.

[0046] The preparation method of clay is as follows:

[0047] Disperse 100 g of nanoclay in 500 ml of 75% volume fraction ethanol aqueous solution, treat with ultrasonic oscillation for 30 min to obtain a dispersion, add 200 ml of silane coupling agent KH-560 to 500 ml of 75% volume fraction ethanol aqueous solution and stir in a 50°C water bath for 60 min, then slowly add the above dispersion within 10 min, keep warm for 15 h, then centrifuge, collect the precipitate, wash repeatedly with anhydrous ethanol and deionized water, and then vacuum dry at 50°C for 24 h.

[0048] The preparation method of hyperbranched polyurethane acrylate emulsion is as follows:

[0049] 40g of polytetrahydrofuran-1000 and 3.56g of dimethylol propionic acid were mixed, stirred and heated to 60°C, 43.81g of 4,4'-dicyclohexylmethane diisocyanate and 0.01g of dibutyltin dilaurate were added dropwise under stirring, stirred and reacted for 60min after the addition was completed, and then the temperature was raised to 80°C and the reaction was continued for 2.5h, 12.32g of hydroxyethyl acrylate was added and the reaction was continued for 1h, and then 13.12g of pentaerythritol triacrylate was added and the reaction was continued for 4h, 4.57g of terminal hydroxyl hyperbranched polyester H101 was added and the reaction was continued for 2h, then the temperature was lowered to 60°C, 2.36g of triethylamine was added and the reaction was continued for 30min, and then the room temperature was restored, and deionized water was added under strong stirring for emulsification to obtain a hyperbranched polyurethane acrylate emulsion with a solid content of 55%.

[0050] The preparation method of hydrogen-containing polysiloxane-modified allyl epoxy resin is as follows:

[0051] Add 0.5 mg of chloroplatinic acid to 100 g of hydrogen-containing polysiloxane (hydrogen content 0.15%), stir and heat to 80-100°C, then slowly add 63 g of allyl epoxy resin (DADGEBA), keep warm and react for 8 hours after the addition, and finally remove low-boiling substances by distillation under reduced pressure.

[0052] The preparation method of straw fiber is as follows:

[0053] Cut the wheat straw into 5-10 cm segments, soak them in a sodium hydroxide solution with a solid-liquid mass ratio of 1:10 at 50°C and a mass concentration of 5wt% for 10 hours, filter, wash with water until neutral, and then dry.

[0054] The preparation method of the straw-soil blocks for the multi-rib sandwich panels is as follows:

[0055] Clay, cement, desulfurized gypsum powder and straw fiber are pre-mixed to obtain a solid material. The polycarboxylic acid water reducer is dissolved in water and added to the solid material and stirred evenly. Then, epoxy resin emulsion, hyperbranched polyurethane acrylate emulsion and hydrogenated polysiloxane-modified allyl epoxy resin are added and stirred for 10 minutes. Finally, triethanolamine and ethylenediamine are added and stirred for 3 minutes. The mixture is poured into a mold and cold-pressed at 20 MPa. After steam curing at 110°C for 5 hours, the mixture is naturally cooled to room temperature, demolded, and the obtained green body is placed in a cool and ventilated place for 7 days.

[0056] Embodiment 2:

[0057] A straw-soil block for a dense-rib sandwich panel is prepared from the following raw materials in parts by weight:

[0058] 40 parts of clay, 25 parts of cement, 15 parts of desulfurized gypsum powder, 10 parts of epoxy resin emulsion, 4 parts of hyperbranched polyurethane acrylate emulsion, 1 part of hydrogenated polysiloxane-modified allyl epoxy resin, 1 part of triethanolamine, 1 part of ethylenediamine, 15 parts of straw fiber, 0.5 part of polycarboxylic acid water reducer, and 30 parts of water.

[0059] The preparation methods of clay, hyperbranched polyurethane acrylate emulsion, hydrogenated polysiloxane-modified allyl epoxy resin and straw fiber are the same as those in Example 1;

[0060] The preparation method of the straw-soil blocks for the multi-rib sandwich panels is as follows:

[0061] Clay, cement, desulfurized gypsum powder and straw fiber are pre-mixed to obtain a solid material. The polycarboxylic acid water reducer is dissolved in water and added to the solid material and stirred evenly. Then, epoxy resin emulsion, hyperbranched polyurethane acrylate emulsion and hydrogenated polysiloxane-modified allyl epoxy resin are added and stirred for 10 minutes. Finally, triethanolamine and ethylenediamine are added and stirred for 3 minutes. The mixture is poured into a mold and cold-pressed at 20 MPa. After steam curing at 110°C for 5 hours, the mixture is naturally cooled to room temperature, demolded, and the obtained green body is placed in a cool and ventilated place for 7 days.

[0062] Embodiment 3:

[0063] A straw-soil block for a dense-rib sandwich panel is prepared from the following raw materials in parts by weight:

[0064] 30 parts of clay, 15 parts of cement, 10 parts of desulfurized gypsum powder, 5 parts of epoxy resin emulsion, 2 parts of hyperbranched polyurethane acrylate emulsion, 0.5 parts of hydrogenated polysiloxane-modified allyl epoxy resin, 1 part of triethanolamine, 1 part of ethylenediamine, 10 parts of straw fiber, 0.1 parts of polycarboxylic acid water reducer, and 20 parts of water.

[0065] The preparation methods of clay, hyperbranched polyurethane acrylate emulsion, hydrogenated polysiloxane-modified allyl epoxy resin and straw fiber are the same as those in Example 1;

[0066] The preparation method of the straw-soil blocks for the multi-rib sandwich panels is as follows:

[0067] Clay, cement, desulfurized gypsum powder and straw fiber are pre-mixed to obtain a solid material. The polycarboxylic acid water reducer is dissolved in water and added to the solid material and stirred evenly. Then, epoxy resin emulsion, hyperbranched polyurethane acrylate emulsion and hydrogenated polysiloxane-modified allyl epoxy resin are added and stirred for 10 minutes. Finally, triethanolamine and ethylenediamine are added and stirred for 3 minutes. The mixture is poured into a mold and cold-pressed at 20 MPa. After steam curing at 110°C for 5 hours, the mixture is naturally cooled to room temperature, demolded, and the obtained green body is placed in a cool and ventilated place for 7 days.

[0068] Comparative Example 1:

[0069] The method is basically the same as Example 1, except that nano clay is directly added without modification by silane coupling agent KH-560.

[0070] Comparative Example 2:

[0071] The process is basically the same as Example 1, except that no epoxy resin emulsion is added.

[0072] Comparative Example 3:

[0073] The method is basically the same as Example 1, except that no hyperbranched polyurethane acrylate emulsion is added.

[0074] Comparative Example 4:

[0075] The method is basically the same as Example 1, except that the self-made hyperbranched polyurethane acrylate emulsion is replaced by commercially available water-based polyurethane modified acrylic emulsion PUA2922 (Cheng Zhenhao).

[0076] Comparative Example 5:

[0077] The process is basically the same as Example 1, except that the hydrogen-containing polysiloxane-modified allyl epoxy resin is not added.

[0078] Performance Testing:

[0079] The straw-soil blocks prepared in Examples 1-3 of the present invention and Comparative Examples 1-5 were used as test samples.

[0080] The mechanical properties are tested according to the standard JC / T422-1991(96) "Non-fired ordinary clay bricks";

[0081] The thermal conductivity was tested using a DRH-300 thermal conductivity tester using a steady-state double-heat plate method. The results of the above test are shown in Table 1 below:

[0082] Table 1:

[0083]

[0084] As can be seen from Table 1 above, the straw-soil blocks prepared by the present invention have excellent mechanical properties and thermal insulation properties, and low water absorption;

[0085] By comparing Example 1 with Comparative Example 1, it can be seen that after the nanoclay is modified by the silane coupling agent KH-560, the various properties of the straw soil blocks are improved;

[0086] By comparing Example 1 with Comparative Examples 2-3, it can be seen that the addition of epoxy resin emulsion and hyperbranched polyurethane acrylate emulsion can improve the mechanical properties and thermal insulation properties of straw soil blocks and reduce water absorption;

[0087] By comparing Example 1 with Comparative Example 4, it can be seen that compared with the commercially available water-based polyurethane modified acrylic emulsion, the hyperbranched polyurethane acrylate emulsion in the present invention has a more obvious improvement on the various properties of the straw soil block;

[0088] By comparing Example 1 with Comparative Example 5, it can be seen that the addition of hydrogen-containing polysiloxane-modified allyl epoxy resin can improve the mechanical properties and thermal insulation properties of the straw-soil blocks and reduce the water absorption rate.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A straw soil block for a ribbed sandwich panel, characterized in that: It is prepared from the following raw materials in parts by weight: 30-40 parts of clay, 15-25 parts of cement, 10-15 parts of desulfurized gypsum powder, 5-10 parts of epoxy resin emulsion, 2-4 parts of hyperbranched polyurethane acrylate emulsion, 0.5-1 parts of hydrogenated polysiloxane-modified allyl epoxy resin, 1-3 parts of organic amine, 10-15 parts of straw fiber, 0.1-1 parts of polycarboxylic acid water reducer and 20-40 parts of water.

2. The straw-soil block for ribbed sandwich panels according to claim 1, characterized in that: The clay is modified by a silane coupling agent.

3. The straw-soil block for multi-rib sandwich panels according to claim 2, characterized in that: The preparation method of the clay is as follows: The nanoclay is dispersed in an ethanol aqueous solution to obtain a dispersion, a silane coupling agent is added to the ethanol aqueous solution and stirred in a 40-60° C. water bath for 30-60 minutes, and then the dispersion is added, and the reaction is kept warm for 10-20 hours, followed by centrifugation, and the precipitate is collected, washed, and dried.

4. The straw-soil block for ribbed sandwich panels according to claim 3, characterized in that: The silane coupling agent is KH-560.

5. The straw-soil block for ribbed sandwich panels according to claim 1, characterized in that: The preparation method of hyperbranched polyurethane acrylate emulsion is as follows: The polytetrahydrofuran and dimethylol propionic acid are mixed and heated to 55-65° C., 4,4'-dicyclohexylmethane diisocyanate and an organic tin catalyst are added dropwise under stirring, and the mixture is stirred for reaction for 30-60 minutes after the addition is completed. The mixture is heated to 75-85° C. and the reaction is continued for 1-5 hours. Hydroxyethyl acrylate is added and the reaction is continued for 1-5 hours. Pentaerythritol triacrylate is added and the reaction is continued for 1-5 hours. Terminal hydroxyl hyperbranched polyester is added and the reaction is continued for 1-5 hours. The mixture is cooled to 40-60° C., triethylamine is added and the reaction is continued for 30-60 minutes. The mixture is then restored to room temperature. Deionized water is added under strong stirring for emulsification to obtain the hyperbranched polyurethane acrylate emulsion.

6. The straw-soil block for ribbed sandwich panels according to claim 1, characterized in that: The preparation method of the hydrogen-containing polysiloxane-modified allyl epoxy resin is as follows: Add chloroplatinic acid to hydrogen-containing polysiloxane, stir and heat to 80-100°C, then slowly add allyl epoxy resin, keep warm and react for 5-10 hours after the addition, and finally remove low-boiling substances by distillation under reduced pressure.

7. The straw-soil block for ribbed sandwich panels according to claim 6, characterized in that: The mass ratio of the hydrogen-containing polysiloxane to the allyl epoxy resin is 1:0.5-1.

8. The straw-soil block for ribbed sandwich panels according to claim 1, characterized in that: The organic amine is a combination of triethanolamine and ethylenediamine; The mass ratio of triethanolamine to ethylenediamine is 1-5:1-5.

9. The straw-soil block for ribbed sandwich panels according to claim 1, characterized in that: The preparation method of the straw fiber is as follows: Cut the crop straw into sections, soak them in a sodium hydroxide solution with a mass concentration of 5-10wt% and a temperature of 40-60°C for 1-10 hours, filter them, wash them with water until they are neutral, and then dry them.

10. A method for preparing a straw-soil block for a multi-ribbed sandwich panel as claimed in any one of claims 1 to 9, characterized in that: Clay, cement, desulfurized gypsum powder and straw fiber are pre-mixed to obtain a solid material, polycarboxylic acid water reducer is dissolved in water and added to the solid material and stirred evenly, epoxy resin emulsion, hyperbranched polyurethane acrylate emulsion and hydrogenated polysiloxane modified allyl epoxy resin are then added and stirred continuously, finally organic amine is added and poured into a mold for cold pressing, demolding is performed after steam curing, and then the material is placed in a dark and ventilated place to the corresponding age.

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