Application of polymer-coated sand in flexible tile adhesives and its products

Abstract

The present invention discloses an application of polymer-coated sand in a flexible tile adhesive and a product thereof. The application is the application of polymer-coated sand in a flexible tile adhesive, and discloses a flexible tile adhesive comprising the above-mentioned polymer-coated sand. The aggregate sand of the present invention is coated with a polymer emulsion to form a layer of polymer film on the surface. The obtained polymer-coated sand is then mixed with other components of the tile adhesive to significantly enhance the bonding strength between the polymer cement slurry formed by redispersible latex powder and cement and the polymer-coated sand, thereby reducing defects caused by insufficient polymer content at the interface, thereby achieving the effect of improving the flexibility of the tile adhesive. Compared with the prior art, the flexible tile adhesive made by using polymer-coated sand can significantly reduce the amount of redispersible latex powder used, and has lower production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of tile adhesives, and specifically to an application of polymer-coated sand in flexible tile adhesives and products thereof. Background Art

[0002] Ceramic tile adhesives are used in areas with unstable substrates, such as light steel stud partitions and plywood partitions. Compared to masonry or concrete walls, these types of partitions are less stable and may deform to a certain extent. In these applications, flexible tile adhesives are needed to resist deformation. In recent years, large-scale ceramic tile slabs and rock slabs have become increasingly popular due to their superior decorative effects, such as in living room backgrounds. These tiles often measure 1.8m*0.9m, 2.4m*1.2m, or even larger, placing higher demands on the flexibility of the tile adhesive to resist shrinkage stress after application.

[0003] Based on the above situation, the JC / T 547-2017 "Ceramic Tile Adhesive" standard also made corresponding regulations, and used lateral deformation indicators S1 and S2 to characterize the flexibility of tile adhesives. That is, the lateral deformation index corresponding to S1-level flexible adhesives is ≥2.5mm, <5mm; the lateral deformation index corresponding to S2-level highly flexible adhesives is ≥5mm.

[0004] To achieve the required flexibility of tile adhesives, a common approach is to add larger amounts of polymer components to the adhesive system. In typical product formulations, to achieve S1 grade, the polymer component, redispersible latex powder, typically requires 6%; to achieve S2 grade, the amount of redispersible latex powder must be 10% or even higher. The addition of large amounts of polymer to tile adhesive systems significantly increases product costs and is not an optimal technical solution.

[0005] CN114956724A discloses a tile adhesive made from the following raw materials by weight: 20%-40% ordinary Portland cement, 30%-60% sand, 5%-10% heavy calcium carbonate powder, 1%-9% redispersible latex powder, 0.2%-1% water-retaining agent, 0.1%-1% early strength agent, 0.05%-0.5% thixotropic lubricant, and 1%-20% wollastonite fiber powder. The wollastonite fiber powder has an aspect ratio of (12-25) to 1 and a particle size of 40-150 μm. This invention combines this specific wollastonite fiber powder with other components to reduce shrinkage and improve deformation resistance of the tile adhesive. The amount of redispersible latex powder can be controlled to 1.8-4%, resulting in a tile adhesive with a lateral deformation range of 1.8-3.1 mm.

[0006] As is known to all, tile adhesive is a composite material composed of cement, polymer, sand, and other functional additives. The main reasons affecting its flexibility are, on the one hand, the modification effect of the polymer on the cement paste, and on the other hand, the interface bonding effect between the paste formed by the polymer and cement and the aggregate sand. Since the polymer added to the tile adhesive will be dispersed throughout the system, it is easy to achieve the modification of the cement paste by the polymer. However, due to the large particle size of the aggregate sand and its large proportion in the system (generally exceeding 50% of the total weight), it is very easy to have a loose bond at the interface, leaving a large number of defects, which leads to a decrease in flexibility. This is manifested as the lateral deformation index being difficult to achieve, or the need to add more polymer to achieve the corresponding lateral deformation index, which leads to a substantial increase in cost. Based on this, the present invention proposes a low-cost flexible tile adhesive from the perspective of sand pretreatment. Summary of the Invention

[0007] The object of the present invention is to provide an application of polymer-coated sand in flexible tile adhesive and a product thereof. The present invention pre-coats aggregate sand with a polymer emulsion, and the obtained polymer-coated sand is then mixed with other components of the tile adhesive, so that the bonding effect between the polymer cement slurry formed by redispersible latex powder and cement and the polymer-coated sand is significantly improved, the amount of redispersible latex powder used is reduced, and the production cost is reduced.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] Application of polymer-coated sand in flexible tile adhesives.

[0010] Preferably, the polymer-coated sand is sand coated with styrene acrylic emulsion and / or ethylene-vinyl acetate copolymer emulsion.

[0011] Preferably, the water content of the polymer coated sand is less than 0.5%.

[0012] Preferably, the polymer-coated sand has a mass ratio of the styrene acrylic emulsion and / or ethylene-vinyl acetate copolymer emulsion to the sand of 10.6-11.2:980, calculated on a dry matter basis. The term "calculated on a dry matter basis" refers to the dry weight of the substance, excluding any solvents contained therein.

[0013] Further preferably, the sand is at least one of river sand, machine-made sand or tailings sand, the sand has a particle size of 0.8-0.1 mm and a water content of less than 0.3%.

[0014] The polymer-coated sand described in the present invention can be prepared using conventional technical means. Specifically, the polymer-coated sand can be prepared by the following method: stirring a formulated amount of sand, then adding a formulated amount of polymer emulsion, stirring until the polymer emulsion is evenly coated on the sand surface, and drying to obtain polymer-coated sand with a moisture content of less than 0.5%. Preferably, the polymer-coated sand can also be prepared by the following method: adding a formulated amount of sand to a horizontal stirred kettle equipped with a stirring paddle, starting the stirring paddle, then adding a formulated amount of polymer emulsion, stirring for 20 minutes to evenly coat the polymer emulsion on the sand surface, and then rapidly drying in an 80°C drying oven to obtain polymer-coated sand with a moisture content of less than 0.5%.

[0015] The present invention also provides a flexible tile adhesive comprising the polymer-coated sand.

[0016] Preferably, the flexible tile adhesive further comprises cement, redispersible latex powder, methyl hydroxypropyl cellulose ether and heavy calcium carbonate.

[0017] Further preferably, the flexible tile adhesive comprises the following raw materials, in parts by weight: 330-395 parts of cement, 506-600 parts of polymer-coated sand, 10-54 parts of redispersible latex powder, 2-5 parts of methyl hydroxypropyl cellulose ether and 30-76 parts of heavy calcium carbonate.

[0018] Most preferably, the flexible tile adhesive comprises the following raw materials, calculated by weight: 360 parts of cement, 566 parts of polymer-coated sand, 24 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether, and 46 parts of heavy calcium carbonate;

[0019] Or the flexible tile adhesive comprises the following raw materials, calculated by weight: 360 parts of cement, 506 parts of polymer-coated sand, 54 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 76 parts of heavy calcium carbonate.

[0020] The present invention also provides a method for preparing the flexible tile adhesive, comprising the following steps: mixing formulated amounts of cement, polymer-coated sand, redispersible latex powder, methyl hydroxypropyl cellulose ether, and heavy calcium carbonate, adding water and stirring to obtain the flexible tile adhesive.

[0021] Preferably, the amount of water added is 23-27% of the mass of the flexible tile adhesive; more preferably 25%.

[0022] Beneficial results of the present invention:

[0023] (1) The aggregate sand of the present invention is coated with a polymer emulsion to form a polymer film on the surface. The obtained polymer-coated sand is then mixed with other components of the tile adhesive, so that the bonding strength between the polymer cement slurry formed by the redispersible latex powder and cement and the polymer-coated sand is significantly enhanced, thereby reducing the defects caused by insufficient polymer content at the interface, thereby achieving the effect of improving the flexibility of the tile adhesive.

[0024] (2) Compared with the existing technology, the flexible tile adhesive made of polymer-coated sand can significantly reduce the amount of redispersible latex powder used and lower the production cost. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention with reference to specific examples. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention.

[0026] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention.

[0027] The present invention does not limit the sources of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commonly available commercially in the art. Among them, the redispersible latex powder was purchased from Wacker Chemie, item number 5010; the ground calcium carbonate had a particle size of 200 mesh; the styrene acrylic emulsion was purchased from BASF, item number 7537; the ethylene-vinyl acetate copolymer emulsion was purchased from Celanese, item number 1320; and the methyl hydroxypropyl cellulose ether was purchased from Shanghai Huiguang, item number 40Z.

[0028] Example 1 A flexible tile adhesive

[0029] The flexible tile adhesive comprises the following raw materials: 330 parts of cement, 600 parts of polymer-coated sand, 38 parts of redispersible latex powder, 2 parts of methyl hydroxypropyl cellulose ether and 30 parts of heavy calcium carbonate.

[0030] The polymer-coated sand is river sand coated with styrene-acrylic emulsion, and the mass ratio of the styrene-acrylic emulsion to the river sand is 10.6:980 based on dry matter.

[0031] Specifically, the preparation method of the polymer-coated sand is as follows: 980g of river sand (particle size of 0.8-0.1mm, water content less than 0.3%) is added to a horizontal stirring kettle with a stirring paddle, the stirring paddle is started, and then 20g of styrene-acrylic emulsion with a glass transition temperature of 0°C and a solid content of 53% is added, stirred for 20 minutes, and the polymer emulsion is evenly coated on the surface of the sand. After rapid drying in an 80°C drying furnace, polymer-coated sand with a water content of less than 0.5% is obtained.

[0032] The preparation method of the flexible tile adhesive comprises the following steps: mixing a formulated amount of cement, polymer-coated sand, redispersible latex powder, methyl hydroxypropyl cellulose ether and heavy calcium carbonate, adding 23% water by weight of the flexible tile adhesive and stirring, thereby obtaining the flexible tile adhesive.

[0033] Example 2 A flexible tile adhesive

[0034] The flexible tile adhesive comprises the following raw materials: 395 parts of cement, 540 parts of polymer-coated sand, 10 parts of redispersible latex powder, 5 parts of methyl hydroxypropyl cellulose ether and 50 parts of heavy calcium carbonate.

[0035] The polymer-coated sand is machine-made sand coated with ethylene-vinyl acetate copolymer emulsion, and the mass ratio of the styrene-acrylic emulsion to the machine-made sand is 11.2:980 based on dry matter.

[0036] Specifically, the preparation method of the polymer-coated sand is as follows: 980g of river sand (particle size of 0.8-0.1mm, water content less than 0.3%) is added to a horizontal stirring kettle with a stirring paddle, the stirring paddle is started, and then 20g of ethylene-vinyl acetate copolymer emulsion with a glass transition temperature of 0°C and a solid content of 56% is added, stirred for 20 minutes, and the polymer emulsion is evenly coated on the sand surface. After rapid drying in an 80°C drying furnace, polymer-coated sand with a water content of less than 0.5% is obtained.

[0037] The preparation method of the flexible tile adhesive comprises the following steps: mixing a formulated amount of cement, polymer-coated sand, redispersible latex powder, methyl hydroxypropyl cellulose ether and heavy calcium carbonate, adding 27% water by weight of the flexible tile adhesive and stirring, thereby obtaining the flexible tile adhesive.

[0038] Example 3 A flexible tile adhesive

[0039] The flexible tile adhesive comprises the following raw materials: 360 parts of cement, 566 parts of polymer-coated sand, 24 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 46 parts of heavy calcium carbonate.

[0040] The polymer-coated sand is river sand coated with styrene-acrylic emulsion, and the mass ratio of the styrene-acrylic emulsion to sand is 11:980 based on dry matter.

[0041] Specifically, the preparation method of the polymer-coated sand is as follows: 980g of river sand (particle size of 0.8-0.1mm, water content less than 0.3%) is added to a horizontal stirring kettle with a stirring paddle, the stirring paddle is started, and then 20g of styrene-acrylic emulsion with a glass transition temperature of 0°C and a solid content of 55% is added, stirred for 20 minutes, and the polymer emulsion is evenly coated on the sand surface. After rapid drying in an 80°C drying furnace, polymer-coated sand with a water content of less than 0.5% is obtained.

[0042] The preparation method of the flexible tile adhesive comprises the following steps: mixing a formulated amount of cement, polymer-coated sand, redispersible latex powder, methyl hydroxypropyl cellulose ether and heavy calcium carbonate, adding 25% water by weight of the flexible tile adhesive and stirring, thereby obtaining the flexible tile adhesive.

[0043] Example 4 A flexible tile adhesive

[0044] The difference between this embodiment and embodiment 3 is that the specific composition of the flexible tile adhesive is different.

[0045] Specifically, the ceramic tile adhesive includes the following raw materials: 360 parts of cement, 506 parts of polymer-coated sand, 54 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 76 parts of heavy calcium carbonate.

[0046] Comparative Example 1: A flexible tile adhesive

[0047] The difference between this comparative example and Example 3 is that the sand is not packaged, and the amount used is 530 parts. At the same time, the amount of redispersible latex powder is increased to 60 parts.

[0048] Specifically, the flexible tile adhesive includes the following raw materials: 360 parts of cement, 530 parts of sand, 60 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 46 parts of heavy calcium carbonate.

[0049] The sand is river sand with a particle size of 0.8-0.1 mm and a water content of less than 0.3%.

[0050] Comparative Example 2: A flexible tile adhesive

[0051] The differences between this comparative example and Example 3 are: (1) the mass ratio of the emulsion to the sand in the polymer-coated sand is different, and the water content of the polymer-coated sand is 0.8%; and (2) the amounts of the components in the flexible tile adhesive are different.

[0052] Specifically, the polymer-coated sand is river sand coated with styrene-acrylic emulsion, and the mass ratio of the styrene-acrylic emulsion to the sand is 15:980 based on dry matter;

[0053] Specifically, the preparation method of the polymer-coated sand is as follows: 980g of river sand (particle size of 0.8-0.1mm, water content less than 0.3%) is added to a horizontal stirring kettle with a stirring paddle, the stirring paddle is started, and then 30g of styrene-acrylic emulsion with a glass transition temperature of 0°C and a solid content of 50% is added, and stirred for 20 minutes to evenly coat the polymer emulsion on the sand surface. After rapid drying in an 80°C drying furnace, polymer-coated sand with a water content of 0.8% is obtained.

[0054] The flexible tile adhesive comprises the following raw materials: 340 parts of cement, 620 parts of polymer-coated sand, 10 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 26 parts of heavy calcium carbonate.

[0055] Sample preparation and testing were carried out according to the method specified in the JC / T 547-2017 Ceramic Tile Adhesive standard, and the main mechanical properties of the tile adhesive were obtained as shown in Table 1.

[0056] Table 1 Main mechanical properties of tile adhesives

[0057]

[0058] The above further describes the present invention in conjunction with specific embodiments. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements shall fall within the scope of protection of the present invention.

Claims

1. The application of polymer coated sand in improving the flexibility of flexible tile adhesives is characterized by: The polymer-coated sand is sand coated with styrene-acrylic emulsion and / or ethylene-vinyl acetate copolymer emulsion; The water content of the polymer-coated sand is less than 0.5%; based on dry matter, the mass ratio of the styrene-acrylic emulsion and / or ethylene-vinyl acetate copolymer emulsion to the sand is 10.6-11.2:980; The flexible tile adhesive comprises the following raw materials, calculated by weight: 330-395 parts of cement, 506-600 parts of polymer-coated sand, 10-54 parts of redispersible latex powder, 2-5 parts of methyl hydroxypropyl cellulose ether, and 30-76 parts of heavy calcium carbonate.

2. The use according to claim 1, characterized in that The sand is at least one of river sand, machine-made sand or tailings sand, the particle size of the sand is 0.8-0.1 mm, and the water content is less than 0.3%.

3. A flexible tile adhesive, characterized in that: The invention comprises the following raw materials: 330-395 parts of cement, 506-600 parts of polymer-coated sand, 10-54 parts of redispersible latex powder, 2-5 parts of methyl hydroxypropyl cellulose ether and 30-76 parts of heavy calcium carbonate. The polymer-coated sand is the polymer-coated sand in the application according to any one of claims 1 to 2.

4. The flexible tile adhesive according to claim 3, characterized in that: The raw materials are as follows: 360 parts of cement, 566 parts of polymer coated sand, 24 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 46 parts of heavy calcium carbonate. Or the flexible tile adhesive comprises the following raw materials, calculated by weight: 360 parts of cement, 506 parts of polymer-coated sand, 54 parts of redispersible latex powder, 4 parts of methyl hydroxypropyl cellulose ether and 76 parts of heavy calcium carbonate.

5. The method for preparing the flexible tile adhesive according to any one of claims 3 to 4, characterized in that: The method comprises the following steps: mixing cement, polymer-coated sand, redispersible latex powder, methyl hydroxypropyl cellulose ether and heavy calcium carbonate in a prescribed amount, adding water and stirring, and obtaining the flexible tile adhesive.

6. The preparation method according to claim 5, characterized in that The amount of water added is 23-27% by weight of the flexible tile adhesive.

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