AQUEOUS DISPERSION AND POLYMER MODIFIED CEMENT-BASED COATING COMPOSITION THEREOF

Abstract

An aqueous dispersion and uses therefor. The aqueous dispersion includes a Component (a), Component (b) and Component (c). Where Component (a) is a polymer prepared by the polymerization of monomers comprising a vinyl ester and an ethylene, where Component (b) is an acrylate-based polymer and where Component (c) is water. A film that is formed from the aqueous dispersion has a glass transition temperature of less than or equal to −7° C. The aqueous dispersion the polymer of the Component (a) has a pot life of longer than or equal to 4 hours after being mixed with cement. Where Component (a) is present in an amount of higher than 35%, based on the total weight of the aqueous dispersion and Component (b) is present in an amount of less than or equal to 20%, based on the total weight of the aqueous dispersion.

Claims

1-15. (canceled)

16. An aqueous dispersion, comprising: an aqueous dispersion comprising Component (a), Component (b) and Component (c); wherein Component (a) is a polymer prepared by the polymerization of monomers comprising a vinyl ester and an ethylene; wherein Component (b) is an acrylate-based polymer; wherein Component (c) is water; wherein a film that is formed from the aqueous dispersion has a glass transition temperature of less than or equal to −7° C.; wherein the aqueous dispersion has a pot life of longer than or equal to 4 hours after being mixed with cement; wherein the pot life of the aqueous dispersion of the polymer of the Component (a) after being mixed with cement is longer than or equal to 4 hours; wherein Component (a) is present in an amount of higher than 35%, based on the total weight of the aqueous dispersion; and wherein Component (b) is present in an amount of less than or equal to 20%, based on the total weight of the aqueous dispersion.

17. The aqueous dispersion of claim 16, wherein the polymer of the Component (a) has a glass transition temperature of less than or equal to 5° C.

18. The aqueous dispersion of claim 16, wherein the content of ethylene units derived from ethylene in the polymer of the Component (a) is more than 22 wt % based on the total weight of the polymer.

19. The aqueous dispersion of claim 16, wherein the polymer of the Component (a) is a stably dispersed in water with polyvinyl alcohol.

20. The aqueous dispersion of claim 16, wherein the Component (a) is a vinyl acetate-ethylene copolymer.

21. The aqueous dispersion of claim 16, wherein the polymer of the Component (b) has a glass transition temperature of less than or equal to −12° C.

22. The aqueous dispersion of claim 16, wherein the pot life of the aqueous dispersion of the polymer of the Component (b) after being mixed with cement is longer than or equal to 4 hours.

23. The aqueous dispersion of claim 16, wherein the Component (b) is present in an amount of from 8% to 20%, based on the total weight of the aqueous dispersion.

24. The aqueous dispersion of claim 16, wherein the polymer of the Component (a) and the polymer of the Component (b) have been prepared by emulsion polymerization.

25. The aqueous dispersion of claim 16, wherein a pH value of the aqueous dispersion is from 5 to 7.

26. The aqueous dispersion of claim 16, wherein a dynamic viscosity of the aqueous dispersion is less than 3,000 mPa.Math.s at 25° C.

27. The aqueous dispersion of claim 16, characterized by a solid content of more than 50 wt %.

28. The aqueous dispersion of claim 16, wherein a plasticizer is present in an amount of lower than 0.1 wt %, based on the total weight of the aqueous dispersion.

29. The aqueous dispersion of claim 16, wherein the aqueous dispersion is a polymer modified cement-based coating composition.

30. The composition of claim 29, wherein a plasticizer is present in an amount of less than 0.1 wt %, based on the total weight of the composition.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] The present invention is further illustrated by the following examples, but is not limited to the scope thereof. Any experimental methods with no conditions specified in the following examples are selected according to the conventional methods and conditions, or product specifications.

Determination of Tg

[0051] An appropriate amount of the aqueous dispersion was taken to be dried at 130° C. for 30 min to form a film. The Tg of the film was tested on NETZSCH DSC 200 F3 in the temperature range of from −70° C. to 100° C. at a scan rate of 10° C./min. The Tg values here are midpoint values.

Determination of Tensile Strength, Elongation at Break and Low-Temperature Flexibility

[0052] The polymer modified cement-based coating film was prepared and its low temperature flexibility at −10° C., tensile strength and elongation at break were tested according to the Chinese national standard GB/T 23445-2009.

[0053] The ingredients in Table 1-2 are all commercially available, with detailed information as follows:

[0054] Aqueous dispersion 1 of vinyl acetate-ethylene copolymer, plasticizer-free, stabilized by PVOH, Tg=−6.0° C., having a solid content of from 54.0% to 56.0%, an ethylene unit content of 24.0 wt % and a pot life of longer than 4 hours after being mixed with cement, supplied by Wacker Chemicals;

[0055] Aqueous dispersion 2 of vinyl acetate-ethylene copolymer, plasticizer-free, stabilized by PVOH, Tg=−5.2° C., having a solid content of from 54.0% to 56.0%, an ethylene unit content of 21.9 wt % and a pot life of longer than 4 hours after being mixed with cement, supplied by Wacker Chemicals;

[0056] Aqueous dispersion 3 of vinyl acetate-ethylene copolymer, plasticizer-free, stabilized by PVOH and a nonionic surfactant, Tg=10.3° C., having a solid content of from 54.0% to 56.0%, an ethylene unit content of 14.4 wt % and a pot life of longer than 4 hours after being mixed with cement, supplied by Wacker Chemicals;

[0057] Aqueous dispersion of vinyl acetate-ethylene-butyl acrylate copolymer, plasticizer-free, stabilized by a nonionic surfactant, Tg=−15.0° C., having a solid content of from 54.0% to 56.0%, an ethylene unit content of 19.1 wt % and a pot life of less than 4 hours after being mixed with cement, supplied by Wacker Chemicals;

[0058] Mowilith DM 686, an aqueous dispersion of styrene-acrylate copolymer, plasticizer-free, stabilized by a surfactant, Tg=−13.0° C., having a solid content of from 54.5% to 57.5% and a pot life of longer than 4 hours after being mixed with cement, supplied by Archroma;

[0059] Mowilith DM 637, an aqueous dispersion of styrene-methacrylate copolymer, plasticizer-free, stabilized by a surfactant, Tg=−6.0° C., having a solid content of from 49.0% to 51.0% and a pot life of longer than 4 hours after being mixed with cement, supplied by Archroma;

[0060] Rhodoline 2809, a nonionic surfactant, AEPO-free, having a an active substance content of 90 wt % and an HLB value of 13.0, supplied by Solvay Fine Chemicals;

[0061] SN-DEFOAMER 318, a defoamer, supplied by Sannopco;

[0062] MELMENT F10, a superplasticizer, supplied by BASF.

[0063] The amounts in Table 1-2 are in parts by weight unless otherwise specified.

EXAMPLES 1-2 AND COMPARATIVE EXAMPLES 1-4

Aqueous Dispersions

[0064] According to the formulation in Table 1, the components were uniformly mixed to obtain an aqueous dispersion with a pH value of from 6 to 7.

[0065] The Tg values of the films formed from the resulting aqueous dispersions and the pot lives of the dispersions after being mixed with cement were tested.

TABLE-US-00001 TABLE 1 Components Ex. 1 Ex. 2 C. Ex. 1 C. Ex. 2 C. Ex. 3 C. Ex. 4 C. Ex. 5 Aqueous dispersion 70 60 — — — — 70 1 of vinyl acetate/ethylene copolymer Aqueous dispersion — — 70 — — — — 2 of vinyl acetate/ethylene copolymer Aqueous dispersion — — — 70 — — — 3 of vinyl acetate/ethylene copolymer Aqueous dispersion — — — — 70 — — of vinyl acetate- ethylene-butyl acrylate copolymer Mowilith DM 686 30 40 30 30 30 20 — Mowilith DM 637 — — — — — — 30 Rhodoline 2809 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SN-DEFOAMER 318 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Index Midpoint Tg value −9.3 −8.0 −2.9 −13.3 −11.9 −6.5 >−7 of the film 9.0 formed from the resulting aqueous dispersion*/° C. Offset Tg value −1.3 −2.7 0.9 −7.1 −3.8 −1.0 >−1 of the film 22.9 formed from the resulting aqueous dispersion*/° C. Pot life of the >4 h >4 h >4 h >4 h <4 h >4 h >4 h resulting aqueous dispersi-on after being mixed with cement/h *For Examples 1-2 and Comparative Examples 1, 3-5, only a single transition temperature was found on the heat flow-temperature curve, indicating that the blend is miscible; In Comparative Example 2, two independent transition temperatures were found on the heat flow-temperature curve, indicating that the blend is immiscible.

EXAMPLE 3

Polymer Modified Cement-Based Coating Compositions

[0066] According to the formulation in Table 2, the aqueous dispersions of Examples 1-2 and Comparative Examples 1-4 were respectively used as the main liquid ingredients, then the liquid ingredients and powder ingredients were respectively mixed well to obtain the liquid and powder components, which were mixed, according to the ratio specified in Table 2, to obtain Type I and Type II polymer modified cement-based coatings.

TABLE-US-00002 TABLE 2 Components Ingredients JS I JS II Liquids Aqueous dispersion 90 85 SN-DEFOAMER 318 0.5 0.8 Water 9.5 14.2 Total 100 100 Powders White cement 40 40 (Grade 32.5) Ground calcium carbonate 30 30 (400 mesh) Wollastonite powder 29.5 29.5 MELMENT F10 0.5 0.5 Total 100 100 Mass ratio of liquid component to powder component 1:0.8 1:1.2

[0067] Table 3 shows the test results of low temperature flexibility at −10° C., tensile strength and elongation at break of the polymer modified cement-based coatings prepared from the aqueous dispersions of Examples 1-2 and Comparative Examples 1-4.

TABLE-US-00003 TABLE 3 JS I JS II Low-temperature Tensile Elongation at Tensile Elongation at flexibility at −10° C. strength/Mpa break/% strength/MPa break/% Ex. 1 Passed 2.14 304.13 3.62 99.69 Ex. 2 Passed 1.66 244.72 NA NA C. Ex. 1 Failed NA NA NA NA C. Ex. 2 Failed NA NA NA NA C. Ex. 3 Failed NA NA NA NA C. Ex. 4 Failed NA NA NA NA C. Ex. 5 Failed 4.13 117.57 4.03 38.59