A waterproof redispersible latex powder and its preparation method

Abstract

The present invention relates to the technical field of building materials, and provides a waterproof redispersible latex powder and a preparation method thereof. The waterproof redispersible latex powder is composed of the following components in percentage by mass: 60% - 80% of a mixed emulsion, 8% - 25% of polyvinyl alcohol, 0.5% - 3% of a silane coupling agent, 1% - 5% of an organic chelating agent, 0.5% - 5% of an anti-caking agent, 0.5% - 2% of a waterproof agent, and 3% - 15% of a filler; the mixed emulsion is composed of an ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and a ROSF9788 emulsion. Through the above technical solution, the problem in the prior art that the redispersible latex powder has poor waterproof performance after ensuring the bonding strength during actual application is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and specifically, to a waterproof redispersible latex powder and a preparation method thereof. Background Art

[0002] Redispersible latex powder is a kind of powder that can be redispersed in water when added with water. After this powder is mixed with water and emulsified, it has the same properties as the original emulsion. Moreover, the packaging of redispersible latex powder is relatively simple during the packaging process, and its volume is relatively small. During transportation, due to its light weight, the cost required for transportation is also relatively low. It is convenient to use and can be directly mixed with raw materials such as cement and gypsum. After the water evaporates, a polymer network structure can be formed, which wraps the aggregate to reduce stress concentration, and at the same time improves the elasticity and toughness of the rigid skeleton, and has excellent adhesion to various substrates. Therefore, it is often used in building materials such as cement and mortar.

[0003] Although redispersible latex powder is widely used in building materials, when it is added to building materials such as plastering mortar and putty and applied in some occasions with higher waterproof requirements, such as bathrooms, building exteriors, roofs, etc., its waterproof property often cannot meet the requirements of actual applications while ensuring the bonding strength. Summary of the Invention

[0004] The present invention provides a waterproof redispersible latex powder and a preparation method thereof, which solve the problem that the waterproof property of redispersible latex powder is poor after ensuring the bonding strength in actual applications in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a waterproof redispersible latex powder, which is composed of the following components in mass percentage: 60% - 80% of mixed emulsion, 8% - 25% of polyvinyl alcohol, 0.5% - 3% of silane coupling agent, 1% - 5% of organic chelating agent, 0.5% - 5% of anti-caking agent, 0.5% - 2% of waterproof agent, and 3% - 15% of filler; the mixed emulsion is composed of ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and ROSF9788 emulsion.

[0007] The mass ratio of the ethylene / vinyl laurate / vinyl chloride terpolymer emulsion to the ROSF9788 emulsion is 3:7 - 9:1.

[0008] As a further technical solution, the silane coupling agent includes one or more of methyltrichlorosilane, aminosilane, vinylsilane, epoxysilane, and allyltrimethoxysilane.

[0009] As a further technical solution, the organic chelating agent includes one of ethylenediaminetetraacetic acid and aminoacetic acid.

[0010] As a further technical solution, the waterproofing agent includes one of a silicone-based waterproofing agent and a fatty acid-based waterproofing agent.

[0011] As a further technical solution, the filler includes one or more of mica, light calcium carbonate, and calcium carbonate; the anti-caking agent includes kaolin or silica.

[0012] The present invention also provides a method for preparing a waterproof redispersible latex powder, comprising the following steps:

[0013] S1. Mix the ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and the ROSF9788 emulsion to obtain a mixed emulsion;

[0014] S2. Add polyvinyl alcohol, a silane coupling agent, an anti-caking agent, and a waterproofing agent to the mixed emulsion and mix to obtain a spray liquid;

[0015] S3. Adopt a centrifugal atomization process to spray-dry the spray liquid to obtain a semi-finished powder;

[0016] S4. Add a filler and an organic chelating agent to the semi-finished powder, stir and mix evenly to obtain a waterproof redispersible latex powder.

[0017] As a further technical solution, the viscosity of the spray liquid in S2 is 0.2 - 0.3 Pa·s.

[0018] As a further technical solution, the temperature during spray drying in S3 is 50 - 200 °C, and the rotation speed of the atomization wheel is 20,000 - 30,000 r / min.

[0019] As a further technical solution, the stirring time in S4 is 30 - 60 min.

[0020] The working principle and beneficial effects of the present invention are as follows:

[0021] 1. In the present invention, a mixed emulsion of an ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and a ROSF9788 emulsion is used as the main raw material, and polyvinyl alcohol is used as a protective colloid. By combining components such as a silane coupling agent, an organic chelating agent, and a waterproofing agent, a redispersible latex powder is prepared, which has excellent adhesiveness and waterproofness.

[0022] 2. In the present invention, the introduction of the silane coupling agent can not only increase the compatibility between the organic and inorganic substances, but also promote the dispersion of the inorganic fillers, making the organic and inorganic components closely connected; when the organic chelating agent is added to the redispersible latex powder and used in combination with building materials such as mortar or cement, it can make the redispersible latex powder and the mortar closely combined; by utilizing the synergistic effect of the silane coupling agent, the organic chelating agent and the waterproofing agent, not only the internal connection of the redispersible latex powder is made close, but also a connection is established with the building materials, so that when the cohesive force of the redispersible latex powder is sufficient in actual application, the waterproof property is significantly improved. Detailed Embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0024] Example 1

[0025] A waterproof redispersible latex powder is composed of the following components in mass percentage: 60% of mixed emulsion, 11% of polyvinyl alcohol, 2% of amino silane, 5% of ethylenediaminetetraacetic acid, 5% of kaolin, 2% of sodium fatty acid, and 15% of mica; the mixed emulsion is composed of an ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and a ROSF9788 emulsion, and the mass ratio of the ethylene / vinyl laurate / vinyl chloride terpolymer emulsion to the ROSF9788 emulsion is 3:7.

[0026] A preparation method of a waterproof redispersible latex powder includes the following steps:

[0027] S1. Mix the ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and the ROSF9788 emulsion to obtain a mixed emulsion;

[0028] S2. Add polyvinyl alcohol, amino silane, kaolin, and sodium fatty acid to the mixed emulsion and mix to obtain a spray liquid; the viscosity of the spray liquid is 0.2 Pa·s;

[0029] S3. Adopt a centrifugal atomization process to spray-dry the spray liquid to obtain a semi-finished powder; the temperature during spray-drying is 50 °C, and the rotation speed of the atomization wheel is 30000 r / min;

[0030] S4. Add mica and ethylenediaminetetraacetic acid to the semi-finished powder and stir for 30 min to mix evenly to obtain the waterproof redispersible latex powder.

[0031] Example 2

[0032] A waterproof redispersible latex powder is composed of the following components by mass percentage: 69% of mixed emulsion, 25% of polyvinyl alcohol, 0.5% of methyltrichlorosilane, 1% of glycine, 0.5% of silica white, 1% of sodium methyl silicate, and 3% of light calcium carbonate; the mixed emulsion is composed of an ethylene / vinyl laurate / vinyl chloride ternary emulsion and a ROSF9788 emulsion, and the mass ratio of the ethylene / vinyl laurate / vinyl chloride ternary emulsion to the ROSF9788 emulsion is 3:7.

[0033] A preparation method of a waterproof redispersible latex powder includes the following steps:

[0034] S1. Mix the ethylene / vinyl laurate / vinyl chloride ternary emulsion and the ROSF9788 emulsion to obtain a mixed emulsion;

[0035] S2. Add polyvinyl alcohol, methyltrichlorosilane, silica white, and sodium methyl silicate to the mixed emulsion and mix them to obtain a spraying liquid; the viscosity of the spraying liquid is 0.25 Pa·s;

[0036] S3. Adopt a centrifugal atomization process to spray-dry the spraying liquid to obtain semi-finished powder; the temperature during spray-drying is 125°C, and the rotation speed of the atomization wheel is 25000 r / min;

[0037] S4. Add light calcium carbonate and glycine to the semi-finished powder, stir for 45 min and mix evenly to obtain the waterproof redispersible latex powder.

[0038] Example 3

[0039] A waterproof redispersible latex powder is composed of the following components by mass percentage: 80% of mixed emulsion, 8% of polyvinyl alcohol, 3% of vinyl silane, 2.5% of glycine, 1.5% of silica white, 0.5% of sodium fatty acid, and 4.5% of light calcium carbonate; the mixed emulsion is composed of an ethylene / vinyl laurate / vinyl chloride ternary emulsion and a ROSF9788 emulsion, and the mass ratio of the ethylene / vinyl laurate / vinyl chloride ternary emulsion to the ROSF9788 emulsion is 3:7.

[0040] A preparation method of a waterproof redispersible latex powder includes the following steps:

[0041] S1. Mix the ethylene / vinyl laurate / vinyl chloride ternary emulsion and the ROSF9788 emulsion to obtain a mixed emulsion;

[0042] S2. Add polyvinyl alcohol, vinyl silane, silica white, and sodium fatty acid to the mixed emulsion and mix them to obtain a spraying liquid; the viscosity of the spraying liquid is 0.3 Pa·s;

[0043] S3. Adopt the centrifugal atomization process to spray-dry the spray liquid to obtain semi-finished powder materials; the temperature during spray-drying is 200 °C, and the rotation speed of the atomization wheel is 20,000 r / min;

[0044] S4. Add light calcium carbonate and aminoacetic acid to the semi-finished powder materials, and stir for 60 min to mix evenly to obtain waterproof redispersible latex powder.

[0045] Example 4

[0046] The difference between this example and Example 3 is only that the mass ratio of the ethylene / vinyl laurate / vinyl chloride ternary emulsion to the ROSF9788 emulsion is 9:1.

[0047] Example 5

[0048] The difference between this example and Example 3 is only that the mass ratio of the ethylene / vinyl laurate / vinyl chloride ternary emulsion to the ROSF9788 emulsion is 5:5.

[0049] Example 6

[0050] The difference between this example and Example 3 is only that the mass ratio of the ethylene / vinyl laurate / vinyl chloride ternary emulsion to the ROSF9788 emulsion is 1:9.

[0051] Example 7

[0052] The difference between this example and Example 3 is only that the mass ratio of the ethylene / vinyl laurate / vinyl chloride ternary emulsion to the ROSF9788 emulsion is 9.5:0.5.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 3 is only that only the ethylene / vinyl laurate / vinyl chloride ternary emulsion is added, and the ROSF9788 emulsion is not added.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 3 is only that only the ROSF9788 emulsion is added, and the ethylene / vinyl laurate / vinyl chloride ternary emulsion is not added.

[0057] Comparative Example 3

[0058] The difference between this comparative example and Example 3 is only that only the organic chelating agent and the waterproof agent are added, and the silane coupling agent is not added.

[0059] Comparative Example 4

[0060] The difference between this comparative example and Example 3 is only that only the silane coupling agent and the waterproof agent are added, and the organic chelating agent is not added.

[0061] Comparative Example 5

[0062] The difference between this comparative example and Example 3 is only that only an organic chelating agent and a silane coupling agent are added, and a waterproofing agent is not added.

[0063] Comparative Example 6

[0064] The difference between this comparative example and Example 3 is only that the added emulsions are Wacker 4023N emulsion and ROSF9788 emulsion; the mass ratio of Wacker 4023N emulsion and ROSF9788 emulsion is 3:7.

[0065] After separately mixing 45 parts of the waterproof redispersible latex powder prepared in Examples 1 to 7 and Comparative Examples 1 to 6 with 300 parts of P142.5 ordinary Portland cement, 600 parts of washed sand, and 200 parts of water to obtain mortar, according to the test method of tensile bond strength in GB / T 29906-2013 "Materials for External Thermal Insulation Composite Systems with Extruded Polystyrene Boards", the tensile bond strengths when bonding with cement mortar and extruded polystyrene boards were respectively tested; according to the test method in DL / T 5126-2001 "Test Procedures for Polymer Modified Cement Mortar", the water absorption rate of the mortar after being immersed in water for seven days was tested, and the test results are shown in Table 1.

[0066] Table 1 Test Results of Tensile Bond Strength and Water Absorption Rate

[0067]

[0068] By comparing the test data of Examples 1 to 5 and Comparative Examples 1 to 6, and Examples 6 to 7, it is found that the tensile bond strengths of the samples in Examples 1 to 5 are all higher than those in Comparative Examples 1 to 6 and Examples 6 to 7, and the water absorption rates of the samples in Examples 1 to 5 are all lower than those in Comparative Examples 1 to 6 and Examples 6 to 7; it shows that the redispersible latex powder prepared with a mixed emulsion of ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and ROSF9788 emulsion as the main raw material, and then combined with components such as silane coupling agent, organic chelating agent, and waterproofing agent, has excellent adhesiveness and waterproofness.

[0069] By comparing the test data of Example 3 and Comparative Examples 1 to 6, it is found that the combined use of silane coupling agent, organic chelating agent, and waterproofing agent can effectively improve the tensile bond strength of the sample and significantly reduce the water absorption rate, indicating that there is a synergistic effect among the silane coupling agent, organic chelating agent, and waterproofing agent, so that when the redispersible latex powder has sufficient adhesion in actual application, the waterproofness is significantly improved.

[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A waterproof redispersible latex powder, characterized in that, It consists of the following components by mass percentage: 60% - 80% of mixed emulsion, 8% - 25% of polyvinyl alcohol, 0.5% - 3% of silane coupling agent, 1% - 5% of organic chelating agent, 0.5% - 5% of anti-caking agent, 0.5% - 2% of waterproofing agent, and 3% - 15% of filler; the mixed emulsion is composed of ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and ROSF9788 emulsion; The mass ratio of the ethylene / vinyl laurate / vinyl chloride terpolymer emulsion to the ROSF9788 emulsion is 3:7 - 9:

1.

2. A waterproof redispersible latex powder according to claim 1, characterized in that, The silane coupling agent includes one or more of methyltrichlorosilane, amino silane, vinyl silane, epoxy silane, allyltrimethoxysilane.

3. A water-proof redispersible latex powder according to claim 1, characterized in that, The organic chelating agent includes one of ethylenediaminetetraacetic acid and glycine.

4. A waterproof redispersible latex powder according to claim 1, characterized in that, The waterproofing agent includes one of silicone waterproofing agent and fatty acid waterproofing agent.

5. A waterproof redispersible latex powder according to claim 1, characterized in that The filler includes one or more of mica, light calcium carbonate, and calcium carbonate; the anti-caking agent includes kaolin or white carbon black.

6. A preparation method of a waterproof redispersible latex powder according to any one of claims 1 to 5, characterized in that, It includes the following steps: S1. Mix the ethylene / vinyl laurate / vinyl chloride terpolymer emulsion and the ROSF9788 emulsion to obtain a mixed emulsion; S2. Add polyvinyl alcohol, silane coupling agent, anti-caking agent, and waterproofing agent to the mixed emulsion and mix to obtain a spraying liquid; S3. Adopt a centrifugal atomization process to spray-dry the spraying liquid to obtain a semi-finished powder material; S4. Add filler and organic chelating agent to the semi-finished powder material, stir and mix evenly to obtain a waterproof redispersible latex powder.

7. The preparation method of a waterproof redispersible latex powder according to claim 6, characterized in that, The viscosity of the spraying liquid in S2 is 0.2 - 0.3 Pa·s.

8. The preparation method of a waterproof redispersible latex powder according to claim 6, characterized in that, The temperature during spray-drying in S3 is 50 - 200 °C, and the rotation speed of the atomization wheel is 20000 - 30000 r / min.

9. The preparation method of a waterproof redispersible latex powder according to claim 6, characterized in that, The stirring time in S4 is 30 - 60 min.

Images