A thermal insulation and crack-resistant mortar based on construction waste and its application

Abstract

This invention provides a thermal insulation and crack-resistant mortar based on construction waste and its application. The raw materials for preparing the thermal insulation and crack-resistant mortar include powder and modified polystyrene particles. The powder includes the following components: cement, redispersible latex powder, additives, and modified rock wool fibers. The modified polystyrene particles are obtained by modifying waste expanded polystyrene boards, and the surface of the modified polystyrene particles is coated with latex powder particles. The modified rock wool fibers are obtained by modifying waste rock wool, and the surface of the modified rock wool fibers is coated with latex powder particles. The thermal insulation and crack-resistant mortar provided by this invention not only has high strength and excellent crack resistance, but also low water absorption.

Description

Technical Field

[0001] This invention belongs to the field of mortar technology and relates to a thermal insulation and crack-resistant mortar based on construction waste and its application. Background Technology

[0002] Currently, some external wall insulation thin plastering systems are gradually approaching their 25-year service life. Repairing and removing external wall insulation thin plastering systems that have reached the end of their service life will generate a large amount of construction waste, such as expanded polystyrene boards and rock wool. At the same time, when repairing external wall insulation systems again, materials with high strength, good crack resistance, low water absorption, wide applicability, and convenient construction are required.

[0003] CN112851272A discloses a polymer crack-resistant mortar formulation and its preparation process. The formulation materials include: cement, sand, water, fly ash, crack-resistant PP fiber, polystyrene granules, and additives. The additives include functional additives, modified chloroprene latex, and hydroxypropyl methylcellulose. The functional additives include: water-retaining agents, thickeners, adhesives, hardeners, anchoring agents, stabilizers, defoamers, and accelerators. This invention's polymer crack-resistant mortar formulation and preparation process improves the wear resistance of the mortar surface after drying and molding by using sulfoaluminate cement and quartz sand instead of ordinary silicate cement and river sand. Simultaneously, by adding various polymers and functional additives, combined with a specialized mortar preparation process, the resulting polymer crack-resistant mortar surface exhibits excellent crack resistance, thus preventing mortar surface peeling and making it suitable for use in harsh environments. The technical solution disclosed in this invention improves the wear resistance and crack resistance of mortar after drying and molding, but has the following technical defects: (1) It does not increase the thickness of a single construction, and there is still a risk of cracking when the thickness is high; (2) This mortar has a high water absorption, a single function, and limited applicability; (3) The production, transportation, and use of the emulsion need to be considered, as well as the production, packaging, transportation, and mixing ratio issues, which reduces efficiency; (4) The use of quartz sand or mineral sand of a specific mesh size causes additional energy consumption, which is not conducive to carbon reduction.

[0004] Therefore, it is desirable to develop a thermal insulation and crack-resistant mortar based on construction waste, which not only has high strength and excellent crack resistance, but also low water absorption. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a thermal insulation and crack-resistant mortar based on construction waste and its applications. This invention utilizes a special process to treat construction waste such as expanded polystyrene boards and rock wool, achieving waste utilization. The mortar provided by this invention exhibits excellent crack resistance, high strength, and low water absorption. Furthermore, this invention improves the overall performance of the mortar, broadens its applicability, and facilitates construction while reducing the number of construction operations.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a thermal insulation and crack-resistant mortar based on construction waste, wherein the raw materials for preparing the thermal insulation and crack-resistant mortar include powder and modified polystyrene particles;

[0008] The powder comprises the following components: cement, redispersible latex powder, additives, and modified rock wool fiber;

[0009] The modified polystyrene particles are obtained by modifying waste expanded polystyrene boards, and the surface of the modified polystyrene particles is coated with latex powder particles.

[0010] The modified rock wool fiber is obtained by modifying waste rock wool, and the surface of the modified rock wool fiber is coated with latex powder particles.

[0011] The key raw material of this invention is construction waste, which is recycled and reused, making it economical, environmentally friendly, energy-saving and low-carbon.

[0012] The modified polystyrene particles and modified rock wool fibers of this invention are uniformly coated with latex powder particles, further improving the uniformity of the latex powder in the system. The redispersible latex powder first improves the water retention of the mortar, forming a film to reduce water evaporation. Secondly, it also plays an additional role in binding and improving the strength of the mortar. Since cement produces many cavities during the setting and solidification process, which become weak parts of the cement, the addition of redispersible latex powder allows it to be reduced to an emulsion and enter the cavities while the cement is solidifying. As the drying process continues, the emulsion is dehydrated again, and the dehydrated polymer forms a continuous film around the cavities. These continuous films attached to the pore walls can effectively absorb pressure from the outside, thereby improving the overall performance of the mortar. At this time, the polymer film can act as a hydrophobic agent without clogging the capillaries, ensuring that the material has good hydrophobicity and air permeability.

[0013] It should be noted that the waste expanded polystyrene board includes expanded polystyrene board obtained when removing the external wall insulation system, and the waste rock wool includes rock wool obtained when removing the external wall insulation system.

[0014] Preferably, the modified polystyrene particles are prepared by the following method:

[0015] (1) The waste expanded polystyrene board is recycled, crushed, and screened to obtain polystyrene particles;

[0016] (2) Mix the mixed emulsion of vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc to obtain a mixture. Add the polystyrene particles obtained in step (1) into the mixture for impregnation and dry to obtain the modified polystyrene particles.

[0017] In this invention, polystyrene particles are modified by using a mixed emulsion of vinyl acetate-ethylene emulsion and silicone-modified acrylic emulsion. Latex powder particles can be coated on the surface of the polystyrene particles. The vinyl acetate-ethylene in the latex powder has good compatibility with redispersible latex powder, while the silicone-modified acrylic in the latex powder has good compatibility with cement, polystyrene particles, and rock wool fibers. This improves the uniformity of the distribution of modified polystyrene particles in the system and their compatibility with cement and other components, thereby improving the product's strength and crack resistance.

[0018] Preferably, the polystyrene particles have a particle size of 1-5 mm, such as 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. The dismantled expanded polystyrene boards can be recycled and crushed using a crusher. By controlling the crusher's speed and frequency, and screening the crushed polystyrene particles, the particle size of the screened polystyrene particles can be controlled to be 1-5 mm.

[0019] Preferably, the mass ratio of the vinyl acetate-ethylene emulsion to the silicone-modified acrylic emulsion is (2-4):1, for example, 2:1, 3:1, or 4:1. If the mass ratio of the vinyl acetate-ethylene emulsion to the silicone-modified acrylic emulsion is too large, the content of the silicone-modified acrylic emulsion is low, and the compatibility of the mixed emulsion with polystyrene particles and rock wool fibers decreases, resulting in a decrease in the tensile bond strength of the final system. If the mass ratio of the vinyl acetate-ethylene emulsion to the silicone-modified acrylic emulsion is too small, the content of the silicone-modified acrylic emulsion is high, and the emulsion may undergo slight demulsification in a strongly alkaline environment, resulting in a decrease in the strength of the final system.

[0020] Preferably, the amount of polyvinyl alcohol added accounts for 10-15% of the total amount of the mixed emulsion, such as 10%, 11%, 12%, 13%, 14%, or 15%. Polyvinyl alcohol acts as a protective colloid. If too much polyvinyl alcohol is added, the water resistance of the latex powder particles and the system will deteriorate in the later stages; if too little polyvinyl alcohol is added, the emulsion particles will agglomerate and fuse during the drying process, which in severe cases may prevent the formation of latex powder or cause adhesion between polystyrene particles.

[0021] Preferably, the amount of talc added accounts for 6-15% of the total amount of the mixed emulsion, such as 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%. As an anti-caking agent, excessive talc addition will increase the emulsion viscosity and make it difficult to spray dry, while insufficient addition will cause the latex particles to agglomerate and flocculate during the drying process, potentially leading to the inability to form latex powder or causing adhesion between polystyrene particles.

[0022] Preferably, the soaking time in step (2) is 20-50 minutes, such as 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes or 50 minutes.

[0023] Preferably, the drying in step (2) is carried out in a fluidized bed.

[0024] Preferably, the drying temperature in step (2) is 40-60°C, such as 40°C, 45°C, 50°C, 55°C or 60°C.

[0025] Preferably, the modified rock wool fiber is prepared by the following method:

[0026] (1) The waste rock wool is recycled, crushed, and screened to obtain rock wool fiber;

[0027] (2) Mix vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc powder to obtain a mixture. Use the mixture to spray rock wool fibers with atomization, and at the same time, separate the rock wool fibers by blowing air. Then spray dry to obtain the modified rock wool fibers.

[0028] In this invention, rock wool fibers are modified by using a mixed emulsion of vinyl acetate-ethylene emulsion and silicone-modified acrylic emulsion. Latex powder can be coated on the surface of the rock wool fibers. The vinyl acetate-ethylene in the latex powder has good compatibility with redispersible latex powder, while the silicone-modified acrylic in the latex powder has good compatibility with cement, polystyrene particles, and rock wool fibers. This allows the modified rock wool fibers to be better distributed in the system, improving the compatibility with components such as cement and redispersible latex powder, and enhancing the system's compressive strength and crack resistance.

[0029] Preferably, the length of the rock wool fibers is 5-10 mm, such as 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. The dismantled rock wool can be recycled and crushed using a crusher. By controlling the speed and frequency of the crusher and performing air separation screening on the crushed rock wool, the length of the rock wool fibers after air separation screening can be controlled to be 5-10 mm.

[0030] Preferably, the mass ratio of the vinyl acetate-ethylene emulsion to the silicone-modified acrylic emulsion is (2-4):1, for example, 2:1, 3:1, or 4:1. If the mass ratio of the vinyl acetate-ethylene emulsion to the silicone-modified acrylic emulsion is too large, the content of the silicone-modified acrylic emulsion will be low, reducing the compatibility of the mixed emulsion with polystyrene particles and rock wool fibers, resulting in a decrease in the tensile bond strength of the final system. If the mass ratio of the vinyl acetate-ethylene emulsion to the silicone-modified acrylic emulsion is too small, the content of the silicone-modified acrylic emulsion will be high, and the emulsion may undergo slight demulsification in a strongly alkaline environment, leading to a decrease in the strength of the final system.

[0031] Preferably, the amount of polyvinyl alcohol added accounts for 14-20% of the total amount of the mixed emulsion, such as 14%, 15%, 16%, 17%, 18%, 19%, or 20%. Polyvinyl alcohol acts as a protective colloid. If too much polyvinyl alcohol is added, the water resistance of the latex powder particles and the system in the later stages will deteriorate; if too little polyvinyl alcohol is added, the emulsion particles will agglomerate and fuse during the drying process, which in severe cases may prevent the formation of latex powder or cause adhesion between rock wool fibers.

[0032] Preferably, the amount of talc added accounts for 10-20% of the total amount of the mixed emulsion, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. As an anti-caking agent, excessive talc addition will increase the emulsion viscosity and make it difficult to spray dry, while insufficient addition will cause the latex particles to agglomerate and flocculate during the drying process, which in severe cases may prevent the formation of latex powder or cause adhesion between rock wool fibers.

[0033] Preferably, the spray drying temperature in step (2) is 140-160°C, such as 140°C, 145°C, 150°C, 155°C or 160°C.

[0034] Preferably, the glass transition temperature of the vinyl acetate-ethylene emulsion is 50-65°C, such as 50°C, 53°C, 55°C, 60°C, 63°C, or 65°C, and the minimum film-forming temperature is 0-10°C, such as 0°C, 2°C, 4°C, 6°C, 8°C, or 10°C. It should be noted that the glass transition temperature and minimum film-forming temperature of the vinyl acetate-ethylene emulsion used in the preparation of modified polystyrene particles and modified rock wool fibers are both within the above-mentioned ranges.

[0035] Preferably, the glass transition temperature of the silicone-modified acrylic emulsion is 50-60℃, such as 50℃, 52℃, 54℃, 56℃, 58℃, or 60℃, and the minimum film-forming temperature is 5-10℃, such as 5℃, 6℃, 7℃, 8℃, 9℃, or 10℃. It should be noted that the glass transition temperature and minimum film-forming temperature of the silicone-modified acrylic emulsion used in preparing modified polystyrene particles and modified rock wool fibers are both within the above-mentioned ranges.

[0036] This invention uses a vinyl acetate-ethylene-organosilicon modified acrylic acid mixed emulsion to pretreat polystyrene particles and rock wool fibers, which can make the latex powder particles uniformly coated on the polystyrene particles and rock wool fibers, improve the flexibility of the polystyrene particles and rock wool fibers, enhance the dispersibility of the polystyrene particles and rock wool fibers, and increase their affinity with the components in the system.

[0037] The vinyl acetate-ethylene emulsion, silicone-modified acrylic emulsion, polyvinyl alcohol, and talc involved in this invention are all commercially available products.

[0038] Preferably, the additives include any one or a combination of at least two of cellulose ethers, early strength agents, starch ethers, or polypropylene (PP) fibers.

[0039] Preferably, the raw materials for preparing the powder include the following components in parts by weight:

[0040]

[0041] Preferably, the amount of cement used in the preparation of the powder can be 800 parts, 830 parts, 850 parts, 880 parts, 900 parts, 930 parts, 950 parts, 980 parts, or 1000 parts, etc., by weight.

[0042] Preferably, the amount of redispersible latex powder used in the preparation of the powder can be 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, or 25 parts by weight.

[0043] Preferably, the amount of cellulose ether used in the preparation of the powder can be 6, 7, 8, 9 or 10 parts by weight.

[0044] Preferably, the amount of early strength agent used in the preparation of the powder can be 6 parts, 7 parts, or 8 parts by weight.

[0045] Preferably, the amount of starch ether used in the preparation of the powder can be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts by weight.

[0046] Preferably, the raw materials for preparing the powder, by weight, include 5, 6, or 7 parts of polypropylene fiber, etc.

[0047] Preferably, the amount of modified rock wool fiber used in the preparation of the powder can be 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts by weight.

[0048] Preferably, the mass ratio of the powder to the modified polystyrene particles is 100:(5-15), for example, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14 or 100:15, etc.

[0049] Preferably, the redispersible latex powder includes vinyl acetate-ethylene copolymer latex powder (VAE latex powder).

[0050] Preferably, the cellulose ether comprises hydroxypropyl methylcellulose ether.

[0051] Preferably, the early strength agent comprises calcium formate.

[0052] Preferably, the length of the polypropylene fiber is 5-8 mm, such as 5 mm, 6 mm, 7 mm or 8 mm.

[0053] Secondly, the present invention provides an application of the thermal insulation and crack-resistant mortar as described in the first aspect in thermal insulation, crack resistance, water seepage prevention, or leveling.

[0054] When using the thermal insulation and crack-resistant mortar of the present invention, the various powder components of the formula can be mixed first to obtain powder, and then the powder can be mixed with water (the mass ratio of powder to water can be 100:(60-80)). Then, modified polystyrene particles are added and stirred evenly before use. It can be used for thermal insulation, crack resistance, water seepage prevention, leveling and other aspects. The thickness of each application can be 1-5cm. The next process can be carried out after the previous process is completely dry.

[0055] Compared with the prior art, the present invention has at least the following beneficial effects:

[0056] (1) The key raw material of this invention is construction waste, which is recycled and reused, making it economical, environmentally friendly, energy-saving and low-carbon.

[0057] (2) The modified polystyrene particles and modified rock wool fibers of the present invention are uniformly coated with latex powder particles, which further improves the uniformity of latex powder in the system. The redispersible latex powder first improves the water retention of the mortar and forms a film to reduce water evaporation. Secondly, it also plays an additional bonding role to improve the strength of the mortar. Since cement will generate many cavities during the setting and solidification process, which become the weak part of the cement, after adding redispersible latex powder, the redispersible latex powder is also reduced to emulsion and enters the cavity while the cement is solidifying. As the drying process continues, the emulsion is dehydrated again. The dehydrated polymer forms a continuous film around the cavity. These continuous films attached to the pore walls can effectively absorb the pressure from the outside, thereby improving the comprehensive performance of the mortar. At this time, the polymer film can play a hydrophobic role and will not block the capillary, ensuring that the material has good hydrophobicity and air permeability.

[0058] (3) The present invention uses modified rock wool fiber, which further improves the compressive strength, crack resistance and heat resistance of the mortar system.

[0059] (4) The modified polystyrene particles and modified rock wool fibers used in this invention, after system curing, together with the latex powder uniformly distributed in the system, form a denser three-dimensional continuous resin film, which improves the strength, water resistance, flexibility and dimensional stability of the mortar system. At the same time, the polystyrene particles further improve the thermal insulation performance of the system.

[0060] (5) The thermal insulation and crack-resistant mortar provided by the present invention has excellent comprehensive performance, broadens the application range, increases the thickness of a single construction, thereby shortening the construction cycle, reducing construction costs, and making it convenient and quick. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0062] The raw material information used in the preparation examples of this invention is as follows:

[0063] Vinyl acetate-ethylene emulsion: Wacker 558 emulsion;

[0064] Organosilicon-modified acrylic emulsion: Badifu RS-2520D;

[0065] Polyvinyl alcohol: Kuraray PVA-205 (Japan);

[0066] Talc powder: particle size 1250 mesh;

[0067] Cement: PO42.5 grey cement.

[0068] Preparation Example 1-1

[0069] This preparation example provides a modified polystyrene particle, the preparation method of which includes the following steps:

[0070] (1) The dismantled expanded polystyrene boards were recycled, crushed, and screened to obtain polystyrene particles with a particle size of 3 mm.

[0071] (2) Mix the mixed emulsion of vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc to obtain a mixture. Add the polystyrene particles obtained in step (1) into the mixture and soak for 30 minutes. Take them out and put them into a fluidized bed for drying. The drying temperature is 55°C to obtain the modified polystyrene particles.

[0072] The mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 3:1, the amount of polyvinyl alcohol added accounts for 12% of the total amount of the mixed emulsion, and the amount of talc added accounts for 10% of the total amount of the mixed emulsion.

[0073] Preparation Examples 1-2

[0074] This preparation example provides a modified polystyrene particle, the preparation method of which includes the following steps:

[0075] (1) The dismantled expanded polystyrene boards were recycled, crushed, and screened to obtain polystyrene particles with a particle size of 1 mm.

[0076] (2) Mix the mixed emulsion of vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc to obtain a mixture. Add the polystyrene particles obtained in step (1) into the mixture and soak for 20 minutes. Take them out and put them into a fluidized bed for drying. The drying temperature is 40°C to obtain the modified polystyrene particles.

[0077] The mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 2:1, the amount of polyvinyl alcohol added accounts for 10% of the total amount of the mixed emulsion, and the amount of talc added accounts for 6% of the total amount of the mixed emulsion.

[0078] Preparation Examples 1-3

[0079] This preparation example provides a modified polystyrene particle, the preparation method of which includes the following steps:

[0080] (1) The dismantled expanded polystyrene boards were recycled, crushed, and screened to obtain polystyrene particles with a particle size of 5 mm.

[0081] (2) Mix the mixed emulsion of vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc to obtain a mixture. Add the polystyrene particles obtained in step (1) into the mixture and soak for 50 minutes. Take them out and put them into a fluidized bed for drying at a temperature of 60°C to obtain the modified polystyrene particles.

[0082] The mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 4:1, the amount of polyvinyl alcohol added accounts for 15% of the total amount of the mixed emulsion, and the amount of talc added accounts for 15% of the total amount of the mixed emulsion.

[0083] Comparative Preparation Example 1-1

[0084] The only difference between this comparative preparation example and preparation example 1-1 is that the mass ratio of vinyl acetate-ethylene emulsion to organosilicon-modified acrylic emulsion is 1:1.

[0085] Comparative preparation examples 1-2

[0086] The only difference between this comparative preparation example and preparation example 1-1 is that the mass ratio of vinyl acetate-ethylene emulsion to organosilicon-modified acrylic emulsion is 5:1.

[0087] Comparative preparation examples 1-3

[0088] The only difference between this comparative preparation example and preparation example 1-1 is that the amount of polyvinyl alcohol added accounts for 5% of the total amount of the mixed emulsion.

[0089] Comparative preparation examples 1-4

[0090] The only difference between this comparative preparation example and preparation example 1-1 is that the amount of polyvinyl alcohol added accounts for 20% of the total amount of the mixed emulsion.

[0091] Comparative preparation examples 1-5

[0092] The only difference between this comparative preparation example and preparation example 1-1 is that the amount of talc added accounts for 2% of the total amount of the mixed emulsion.

[0093] Comparative preparation examples 1-6

[0094] The only difference between this comparative preparation example and preparation example 1-1 is that the amount of talc added accounts for 20% of the total amount of the mixed emulsion.

[0095] The phenomena observed and recorded during the preparation process of Preparation Examples 1-1 to 1-3, and Comparative Preparation Examples 1-1 to 1-6, as well as the appearance of the prepared modified polystyrene particles, are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] Preparation Example 2-1

[0100] This preparation example provides a modified rock wool fiber, the preparation method of which includes the following steps:

[0101] (1) The dismantled rock wool was recycled and crushed using a crusher, and then air-separated and screened to obtain rock wool fibers with a length of 8mm.

[0102] (2) Mix vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc powder to obtain a mixture. Use the mixture to spray rock wool fibers with atomization, and at the same time, separate the rock wool fibers by blowing air. Then, spray dry in a drying tower at 150°C to obtain the modified rock wool fibers.

[0103] The mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 3:1, the amount of polyvinyl alcohol added accounts for 16% of the total amount of the mixed emulsion, and the amount of talc added accounts for 12% of the total amount of the mixed emulsion.

[0104] Preparation Example 2-2

[0105] This preparation example provides a modified rock wool fiber, the preparation method of which includes the following steps:

[0106] (1) The dismantled rock wool was recycled and crushed using a crusher, and then air-separated and screened to obtain rock wool fibers with a length of 5mm.

[0107] (2) Mix vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc powder to obtain a mixture. Use the mixture to spray rock wool fibers with atomization, and at the same time, separate the rock wool fibers by blowing air. Then, spray dry in a drying tower at 140°C to obtain the modified rock wool fibers.

[0108] The mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 2:1, the amount of polyvinyl alcohol added accounts for 14% of the total amount of the mixed emulsion, and the amount of talc added accounts for 10% of the total amount of the mixed emulsion.

[0109] Preparation Examples 2-3

[0110] This preparation example provides a modified rock wool fiber, the preparation method of which includes the following steps:

[0111] (1) The dismantled rock wool is recycled and crushed using a crusher, and then air-separated and screened to obtain rock wool fibers with a length of 10mm.

[0112] (2) Mix vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol and talc powder to obtain a mixture. Use the mixture to spray rock wool fibers with atomization, and at the same time, separate the rock wool fibers by blowing air. Then, spray dry in a drying tower at 160°C to obtain the modified rock wool fibers.

[0113] The mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 4:1, the amount of polyvinyl alcohol added accounts for 20% of the total amount of the mixed emulsion, and the amount of talc added accounts for 20% of the total amount of the mixed emulsion.

[0114] Comparative Preparation Example 2-1

[0115] The only difference between this comparative preparation example and preparation example 2-1 is that the mass ratio of vinyl acetate-ethylene emulsion to organosilicon-modified acrylic emulsion is 1:1.

[0116] Comparative Preparation Example 2-2

[0117] The only difference between this comparative preparation example and preparation example 2-1 is that the mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is 5:1.

[0118] Comparative preparation examples 2-3

[0119] The only difference between this comparative preparation example and preparation example 2-1 is that the amount of polyvinyl alcohol added accounts for 10% of the total amount of the mixed emulsion.

[0120] Comparative preparation examples 2-4

[0121] The only difference between this comparative preparation example and preparation example 2-1 is that the amount of polyvinyl alcohol added accounts for 25% of the total amount of the mixed emulsion.

[0122] Comparative preparation examples 2-5

[0123] The only difference between this comparative preparation example and preparation example 2-1 is that the amount of talc added accounts for 5% of the total amount of the mixed emulsion.

[0124] Comparative preparation examples 2-6

[0125] The only difference between this comparative preparation example and preparation example 2-1 is that the amount of talc added accounts for 25% of the total amount of the mixed emulsion.

[0126] The phenomena observed and recorded during the preparation process of Preparation Examples 2-1 to 2-3, and Comparative Preparation Examples 2-1 to 2-6, as well as the appearance of the prepared modified polystyrene particles, are shown in Table 2.

[0127] Table 2

[0128]

[0129]

[0130] Unless otherwise stated, the raw material information used in Examples 1-19 of the present invention is as follows:

[0131] Redispersible latex powder: VAE latex powder;

[0132] Cellulose ether: Hydroxypropyl methylcellulose ether;

[0133] Early strength agent: calcium formate;

[0134] Starch ether: T300;

[0135] Polypropylene fiber: 6mm in length.

[0136] Example 1

[0137] This embodiment provides a thermal insulation and crack-resistant mortar based on construction waste, wherein the raw materials for preparing the thermal insulation and crack-resistant mortar include powder and modified polystyrene particles;

[0138] The raw materials for preparing the powder include the following components in parts by weight:

[0139]

[0140] The mass ratio of the powder to the modified polystyrene particles is 100:10.

[0141] The modified polystyrene particles were prepared in Preparation Example 1-1, and the modified rock wool fibers were prepared in Preparation Example 2-1.

[0142] Example 2

[0143] This embodiment provides a thermal insulation and crack-resistant mortar based on construction waste, wherein the raw materials for preparing the thermal insulation and crack-resistant mortar include powder and modified polystyrene particles;

[0144] The raw materials for preparing the powder include the following components in parts by weight:

[0145]

[0146] The mass ratio of the powder to the modified polystyrene particles is 100:5.

[0147] The modified polystyrene particles were prepared in Preparation Example 1-2, and the modified rock wool fibers were prepared in Preparation Example 2-2.

[0148] Example 3

[0149] This embodiment provides a thermal insulation and crack-resistant mortar based on construction waste, wherein the raw materials for preparing the thermal insulation and crack-resistant mortar include powder and modified polystyrene particles;

[0150] The raw materials for preparing the powder include the following components in parts by weight:

[0151]

[0152] The mass ratio of the powder to the modified polystyrene particles is 100:15.

[0153] The modified polystyrene particles were prepared in Preparation Examples 1-3, and the modified rock wool fibers were prepared in Preparation Examples 2-3.

[0154] Example 4

[0155] The only difference between this embodiment and Embodiment 1 is that the mass ratio of the powder to the modified polystyrene particles is 100:3.

[0156] Example 5

[0157] The only difference between this embodiment and Embodiment 1 is that the mass ratio of the powder to the modified polystyrene particles is 100:20.

[0158] Example 6

[0159] The only difference between this embodiment and Embodiment 1 is that the modified rock wool fiber is 10 parts by weight.

[0160] Example 7

[0161] The only difference between this embodiment and Embodiment 1 is that the modified rock wool fiber has a weight ratio of 25 parts.

[0162] Examples 8-13

[0163] The only difference between Examples 8-13 and Example 1 is that the modified polystyrene particles prepared in Preparation Example 1-1 are replaced with equal amounts of the modified polystyrene particles prepared in Comparative Preparation Examples 1-1 to 1-6.

[0164] Examples 14-19

[0165] The only difference between Examples 14-19 and Example 1 is that the modified rock wool fibers prepared in Preparation Example 2-1 are replaced with equal amounts of the modified rock wool fibers prepared in Comparative Preparation Examples 2-1 to 2-6.

[0166] Example 20

[0167] The only difference between this embodiment and Embodiment 1 is that the redispersible latex powder (VAE latex powder) is replaced with an equal amount of polyvinyl alcohol 1788 powder.

[0168] Comparative Example 1

[0169] The only difference between this comparative example and Example 1 is that the modified polystyrene particles are replaced with an equal amount of polystyrene particles (with a particle size of 3 mm, i.e., the polystyrene particles obtained from step (1) of Preparation Example 1-1).

[0170] Comparative Example 2

[0171] The only difference between this comparative example and Example 1 is that the modified rock wool fiber is replaced with an equal amount of rock wool fiber (8 mm in length, i.e., the rock wool fiber obtained from step (1) of Preparation Example 2-1).

[0172] The powders in each embodiment or comparative example were mixed with water at a weight ratio of 100:70, and then the modified polystyrene particles of the corresponding embodiment or comparative example were added to obtain a uniformly mixed thermal insulation and crack-resistant mortar. The relevant performance tests were carried out in accordance with JG / T 158-2013 "Materials for External Wall Insulation System of Adhesive Powder Polystyrene Particles". The specific test items and test results are shown in Tables 3 and 4.

[0173] Table 3

[0174]

[0175]

[0176]

[0177] Table 4

[0178]

[0179] As can be seen from Tables 3 and 4, the thermal insulation and crack-resistant mortars provided in Examples 1-3 of the present invention can meet the requirements for linear shrinkage rate, impact strength and compressive strength, and have high tensile strength with different substrates.

[0180] The linear shrinkage rate and compressive strength of the thermal insulation and crack-resistant mortar provided in Comparative Example 1 do not meet the requirements, and the tensile strength is low when compared with different substrates. The linear shrinkage rate, impact strength and compressive strength of the thermal insulation and crack-resistant mortar provided in Comparative Example 2 do not meet the requirements.

[0181] In summary, this invention modifies polystyrene particles and rock wool fibers using a mixed emulsion of vinyl acetate-ethylene emulsion and silicone-modified acrylic emulsion. This allows latex powder particles to coat the surfaces of the polystyrene particles and rock wool fibers. The vinyl acetate-ethylene in this latex powder exhibits good compatibility with redispersible latex powder, while the silicone-modified acrylic in the latex powder shows good compatibility with cement, polystyrene particles, and rock wool fibers. This improves the uniformity of the distribution of modified polystyrene particles within the system and their compatibility with cement and other components, thereby enhancing the tensile bond strength, compressive strength, dimensional stability, and impact resistance of the product. Furthermore, a suitable ratio of vinyl acetate-ethylene emulsion, silicone-modified acrylic emulsion, PVA, and talc can further improve the dispersion and performance of the modified polystyrene particles and modified rock wool fibers during the modification and mixing processes, effectively improving various properties of the hardened thermal insulation and crack-resistant mortar, such as water resistance, compressive strength, and thermal conductivity.

[0182] The applicant declares that this invention illustrates the thermal insulation and crack-resistant mortar based on construction waste and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the product, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A thermal insulation and crack-resistant mortar based on construction waste, characterized in that, The raw materials for preparing the thermal insulation and crack-resistant mortar include powder and modified polystyrene particles; the mass ratio of the powder to the modified polystyrene particles is 100:(5-15); The raw materials for preparing the powder include the following components in parts by weight: 800-1000 parts cement; 15-25 parts of redispersible latex powder; 6-10 parts of cellulose ether; Early-strength agent 6-8 parts; Starch ether 4-10 parts; 5-7 parts of polypropylene fiber; 12-20 parts modified rock wool fiber; The modified polystyrene particles are obtained by modifying waste expanded polystyrene boards, and the surface of the modified polystyrene particles is coated with latex powder particles. The modified polystyrene particles were prepared by the following method: (1) The waste expanded polystyrene board is recycled, crushed, and screened to obtain polystyrene particles; (2) Mix the mixed emulsion of vinyl acetate-ethylene emulsion and organosilicon modified acrylic emulsion, polyvinyl alcohol, and talc to obtain a mixture. Add the polystyrene particles obtained in step (1) into the mixture for impregnation and drying to obtain the modified polystyrene particles. The modified rock wool fiber is obtained by modifying waste rock wool, and the surface of the modified rock wool fiber is coated with latex powder particles. The modified rock wool fiber is prepared by the following method: (a) The waste rock wool is recycled, crushed, and screened to obtain rock wool fibers; (b) A mixture of vinyl acetate-ethylene emulsion and organosilicon-modified acrylic emulsion, polyvinyl alcohol, and talc is mixed to obtain a mixture. The mixture is then used to atomize and spray rock wool fibers while simultaneously separating the rock wool fibers by blowing air. Finally, the mixture is spray-dried to obtain the modified rock wool fibers.

2. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The polystyrene particles in step (1) have a particle size of 1-5 mm.

3. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, In step (2), the mass ratio of vinyl acetate-ethylene emulsion to silicone-modified acrylic emulsion is (2-4):

1.

4. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, In step (2), the amount of polyvinyl alcohol added is 10-15% of the mass percentage of the amount of the mixed emulsion added.

5. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, In step (2), the amount of talc added is 6-15% by mass of the amount of the mixed emulsion added.

6. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The soaking time in step (2) is 20-50 minutes.

7. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The drying in step (2) is carried out in a fluidized bed.

8. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The drying temperature in step (2) is 40-60℃.

9. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The rock wool fibers in step (a) are 5-10 mm in length.

10. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The mass ratio of the vinyl acetate-ethylene emulsion and the silicone-modified acrylic emulsion in step (b) is (2-4):

1.

11. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The amount of polyvinyl alcohol added in step (b) is 14-20% by mass of the amount of the mixed emulsion added.

12. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The amount of talc added in step (b) is 10-20% by mass of the amount of the mixed emulsion added.

13. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The spray drying temperature in step (b) is 140-160°C.

14. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The redispersible latex powder includes vinyl acetate-ethylene copolymer latex powder.

15. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The cellulose ether includes hydroxypropyl methylcellulose ether.

16. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The early strength agent includes calcium formate.

17. The thermal insulation and crack-resistant mortar according to claim 1, characterized in that, The length of the polypropylene fiber is 5-8 mm.

18. The application of a thermal insulation and crack-resistant mortar as described in any one of claims 1-17 in thermal insulation, crack resistance, waterproofing, or leveling.

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