A powder defoamer for self-leveling cement

Abstract

The present invention discloses a powder defoamer for self-leveling cement, belonging to the technical field of cement defoamers. 10-30% of polyether-modified polyorganosiloxane A, 10-30% of polyether B, 5-20% of environmentally friendly plasticizer C, and 0.1-5% of anionic surfactant D are pre-mixed evenly to obtain a mixture M, and then the mixture M is added to 50-70% of silica E and stirred and mixed to obtain a powder defoamer product. The powder defoamer prepared by the present invention has a higher slurry density when used in cement, and has fewer pores and oil spots after the cement hardens. The compressive strength and aesthetics after the cement slurry hardens are both good, and it has broad industrial application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of cement defoamers, and particularly relates to a powder defoamer for self-leveling cement. Background Art

[0002] Self-leveling cement is a special type of cement mortar, usually used for floor leveling and repair. When preparing self-leveling cement, the problem of air bubbles often occurs, and these air bubbles affect the fluidity and surface flatness of the self-leveling cement. The main function of the defoamer is to change the surface tension of the cement mortar, reduce the generation and stability of air bubbles, thereby improving the fluidity and self-leveling performance of the cement mortar, increasing the wet density of the mortar, enhancing the compressive and flexural strengths of the cement mortar after hardening, and improving the apparent state.

[0003] In CN111936446A, a cement defoaming composition is prepared using polyether and phosphate ester. This solution can take into account defoaming and the apparent state after hardening, but the phosphate ester substances used generally have toxicity and environmental protection problems. At the same time, it is difficult to mix the liquid product evenly when used in cement. In CN102407033A, an emulsified silicone emulsion is sprayed onto a carrier to prepare a solid defoamer. This solution has good defoaming performance, but conventional silicone materials are prone to precipitate on the surface of the cement mortar, resulting in abnormal appearance. CN108164181A discloses a concrete defoamer composed of fatty alcohol polyoxyethylene ether phosphate, polyether, emulsifier, wetting agent, thickener, compounding agent, and water. By introducing fatty alcohol polyoxyethylene ether phosphate, the chemical stability of the defoamer is improved. However, its defoaming performance still has room for improvement.

[0004] In summary, the commonly used defoamers for cement are of categories such as silicone, fatty alcohol polyether, and phosphate ester. Among them, silicone-based products have good performance but poor compatibility, and problems such as oil spot precipitation appear on the surface after cement hardening; fatty alcohol polyethers have good compatibility but relatively weak defoaming performance; phosphate ester products are toxic and have safety and environmental protection problems. Therefore, there is an urgent need for a powder defoamer for self-leveling cement with excellent defoaming and foam suppression performance, less precipitation, and easy to use, to solve the problems that the defoamers for self-leveling cement produced by the existing technology often have insufficient performance or more precipitation. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the present invention discloses a powder defoamer for self-leveling cement, which has excellent defoaming and foam suppression performance, less precipitation, and is easy to use.

[0006] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0007] A powder defoamer for self-leveling cement, which is composed of the following components in weight ratio: 10-30% of polyether-modified polyorganosiloxane A, 10-30% of polyether B, 5-20% of environmental protection plasticizer C, 0.1-5% of anionic surfactant D, and 50-70% of silica E.

[0008] Further, the powder defoamer for self-leveling cement is composed of the following components in weight percentage: 10-14% of polyether-modified polyorganosiloxane A, 25-30% of polyether B, 5-10% of environmental protection plasticizer C, 0.1-1% of anionic surfactant D, and 50-54.9% of silica E.

[0009] Further, the powder defoamer for self-leveling cement is composed of the following components in weight percentage: 14% of polyether-modified polyorganosiloxane A, 25% of polyether B, 10% of environmental protection plasticizer C, 1% of anionic surfactant D, and 50% of silica E.

[0010] Further, the polyether-modified polyorganosiloxane A is composed of the following basic units: R a R 1 b SiO (3 - a-b) / 2 ; where a represents a natural number from 1 to 2, b represents a natural number from 0 to 2, R can be the same or different, R is selected from methyl or phenyl, R 1 can be the same or different, R 1 is selected from methyl or -CH 2 CH 2 CH 2 (CH 2 CH 2 O) c (CH 2 CHCH 3 O) d R 2 , where c represents a natural number from 0 to 15, d represents a natural number from 0 to 60, R 2 is selected from a hydrogen atom or methyl.

[0011] Further, the structural formula of the polyether B is: R 3 (CH 2 CH 2 O) c (CH 2 CHCH 3 O) d R 2 , where c represents a natural number from 0 to 15, d represents a natural number from 0 to 60; R 2 is selected from a hydrogen atom or methyl, and R 3 is a hydrogen atom or a hydrocarbon group with 1 to 18 carbon atoms.

[0012] Further, the environmental protection plasticizer C is selected from one of tributyl citrate, acetyl tributyl citrate and epoxidized soybean oil.

[0013] Further, the anionic surfactant D is a sulfonate-type anionic surfactant, and is selected from one of sulfofatty acid alkyl ester salts, olefin sulfonates, alkane sulfonates and linear alkylbenzene sulfonates.

[0014] Further, the silica E is hydrophilic silica, and its specific surface area is 50-500 m 2 / g.

[0015] Further, the preparation method of the powder defoamer for self-leveling cement is as follows: uniformly mix the polyether-modified polyorganosiloxane A, polyether B, environmental protection plasticizer C, and anionic surfactant D to obtain a mixture M, and add M to the silica E and stir to mix evenly to obtain the powder defoamer product.

[0016] Further, the application of the powder defoamer for self-leveling cement in defoaming self-leveling cement.

[0017] Compared with the prior art, the advantages of this application are:

[0018] 1) The powder defoamer for self-leveling cement obtained by the present invention has excellent defoaming and foam-suppressing performance, less precipitation on the surface of cement mortar, and is convenient to use.

[0019] 2) The powder defoamer for self-leveling cement obtained by the present invention is easy to package and transport, and there is no risk of stratification and precipitation.

[0020] 3) The powder defoamer for self-leveling cement obtained by the present invention has good degassing effect, can effectively improve the wet density of mortar and the compressive strength after hardening, and the appearance of the mortar is more beautiful after hardening. Specific Embodiments

[0021] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following specific embodiments are used to make a detailed description of the specific implementation manners of the present invention.

[0022] Example 1

[0023] A powder defoamer for self-leveling cement adopts the following formula:

[0024] Component A is a polyether-modified polyorganosiloxane containing phenyl, accounting for 14%,

[0025]

[0026] Component B is a polyether, and its structural formula is C 18 H36 (CH 2 CH 2 O) 5 (CH 2 CHCH 3 O) 15 H, accounting for 25%;

[0027] Component C is tributyl acetylcitrate, accounting for 10%;

[0028] Component D is sodium diethylhexyl sulfosuccinate, accounting for 1%;

[0029] Component E is A200 silica, accounting for 50%.

[0030] The preparation method is as follows: Put the four components A, B, C, and D into a container, mix them evenly at room temperature to obtain mixture M. Put component E into a gravity-free mixer and stir to mix evenly, and then spray mixture M into the gravity-free mixer. By adopting the spraying feeding method, the mixing efficiency can be improved, the prepared product is more uniform, the appearance of agglomerates is reduced, and finally the powdery defoaming agent product S1 is obtained.

[0031] Example 2

[0032] A powdery defoaming agent for self-leveling cement adopts the following formula:

[0033] The structural formula of component A is as follows, accounting for 10%,

[0034]

[0035] The polyether structural formula of component B is C 16 H 36 (CH 2 CH 2 O) 10 (CH 2 CHCH 3 O) 20 CH 3 , accounting for 30%;

[0036] Component C is tributyl citrate, accounting for 5%;

[0037] Component D is sodium dodecylbenzenesulfonate, accounting for 0.1%;

[0038] Component E is A200 silica, accounting for 54.9%.

[0039] The preparation method is the same as that in Example 1, and finally the powdery defoaming agent product S2 is obtained.

[0040] Example 3

[0041] A powder defoamer for self-leveling cement, with the following formula:

[0042] Component A has the following structural formula and accounts for 30%.

[0043]

[0044] Component B is polyethylene glycol with a degree of polymerization of 15, and its structural formula is HO(CH 2 CH 2 O) 15 H, accounting for 10%; Component C is epoxy soybean oil, accounting for 5%;

[0045] Component D is sodium dodecyl sulfate, accounting for 5%;

[0046] Component E is A200 silica, accounting for 50%.

[0047] The preparation method is the same as that of Example 1, and finally the powdery defoamer product S3 is obtained.

[0048] Example 4

[0049] A powder defoamer for self-leveling cement, with the following formula:

[0050] Component A has the following structural formula and accounts for 10%.

[0051]

[0052] Component B is polypropylene glycol with a degree of polymerization of 60, and its structural formula is HO(CH 2 CHCH 3 O) 60 H, accounting for 10%; Component C is tributyl acetylcitrate, accounting for 20%;

[0053] Component D is sodium dodecylbenzenesulfonate, accounting for 3%;

[0054] Component E is A150 silica, accounting for 57%.

[0055] The preparation method is the same as that of Example 1, and finally the powdery defoamer product S4 is obtained.

[0056] Example 5

[0057] A powder defoamer for self-leveling cement, with the following formula:

[0058] Component A has the following structural formula and accounts for 14%.

[0059]

[0060] Component B is polypropylene glycol with a degree of polymerization of 30, and its structural formula is HO(CH 2 CHCH 3 O) 30 H, with a proportion of 10%;

[0061] Component C is tributyl acetylcitrate, with a proportion of 5%;

[0062] Component D is sodium C14-16 olefin sulfonate, with a proportion of 1%;

[0063] Component E is A150 silica, with a proportion of 70%.

[0064] The preparation method is the same as that in Example 1, and finally the powdery defoamer product S5 is obtained.

[0065] Comparative Example 1

[0066] According to the method described in Patent CN102491679, first, 10 parts of dimethyl silicone oil with a viscosity of 500 mPa·s, 2 parts of hydroxyl silicone oil with a viscosity of 2000 mPa·s, 3 parts of polyether-modified silicone oil with a viscosity of 500 mPa·s, and 1 part of precipitated silica D10 are mixed and heated to 140 °C and kept warm for 4 h to make silicone paste; then, 10 parts of the prepared silicone paste, 2 parts of Tween 80, 2 parts of Span 60, and 1 part of OP-4 are mixed and heated to 80 °C, and then 35 parts of water are slowly added while stirring, and finally the emulsion defoamer C1 is obtained.

[0067] Comparative Example 2

[0068] According to the method described in Patent CN110272222, in a reaction vessel, 45 g of nonylphenol polyoxyethylene ether and 6 g of fumed hydrophilic silica with a specific surface area of 50 m 2 / g are added, and at a temperature of 60 °C, under high-speed stirring at a speed of 2000 rpm for 2 h, it is the defoaming active substance M1. Take 2 g of 2-octyldodecanol and 4 g of fumed hydrophilic silica with a specific surface area of 50 m 2 / g, and at a temperature of 120 °C and a speed of 200 rpm under high-speed stirring for 2 h, it is the defoaming active substance M2. Mix M1, M2, 3 g of octyldodecanol, and 40 g of carrier magnesium silicate through a pulverizer and then sieve to obtain the prepared defoamer C2.

[0069] Defoamer performance test:

[0070] The wet density of the mortar was tested with reference to the test method specified in the "Standard Test Method for Basic Properties of Building Mortars" (JGJ / T 70-2009). The self-leveling mortar (with a defoamer addition of 2‰) after mixing was poured into a clean graduated cylinder to measure the volume and mass of the mortar respectively. The wet density of the mortar was calculated through the formula ρ = m / v. The larger the obtained density value, the lower the air content in the mortar and the better the defoaming effect. The test results are shown in Table 1:

[0071] Table 1: Comparison table of wet density of mortars with powdery defoamer products S1 - S5 and defoamers C1, C2

[0072]

[0073] It can be seen from the table that the wet density of the mortars with the defoamers S1 - S5 of the present invention added is higher than that of the blank sample without defoamer and the defoamer samples C1 - C2 prepared by the prior art solutions. Among them, the S1 and S2 solutions contain more polyether-modified silicone, and this material has a good degassing and defoaming effect. The density of the mortar using this solution is also slightly higher than that of other invention samples.

[0074] Compressive strength test of the hardened mortar:

[0075] The compressive strength test was carried out with reference to the method specified in "Cementitious Self-Leveling Mortar for Floor" (JC / T 985-2017). The wet density and the compressive strength after hardening of the mortar of the blank sample without defoamer and the mortars with 2‰ different defoamers added were tested respectively. The specific results are shown in Table 2:

[0076] Table 2: Comparison table of compressive strength after hardening of the blank sample mortar and the mortars with 2‰ different defoamers added

[0077] Blank sample S1 S2 S3 S4 S5 C1 C2 Compressive strength at 1d (MPa) 7.15 9.43 9.35 9.27 9.19 9.26 8.32 8.81 Compressive strength at 28d (MPa) 40.08 42.15 41.97 41.75 41.31 41.98 40.53 40.95

[0078] It can be seen from the test results that the compressive strength of the self-leveling mortar samples S1 - S5 with the defoamers of the present invention added 1 day and 28 days after hardening is significantly improved compared with the blank sample without defoamer and the samples with other defoamer products C1, C2 added.

[0079] Appearance test:

[0080] For the hardened mortar blocks, 10 cm * 10 cm square areas were selected respectively to observe whether there were needle-shaped air holes and white oil spots on their surfaces. The fewer the needle-shaped air holes, the better the defoaming effect, and the fewer the oil spots, the smaller the influence of the defoamer on the appearance of the mortar. The specific results are shown in Table 3:

[0081] Table 3: Comparison table of air holes and oil spots after hardening of the blank sample mortar and the mortars with 2‰ different defoamers added

[0082] Blank sample S1 S2 S3 S4 S5 C1 C2 Pore condition × ★★★ ★★★ ★★★ ★★ ★★ ★ ★ Oil stain condition ★★★ ★★ ★★ ★★ ★★★ ★★★ × ★★

[0083] "×" indicates a relatively poor state and has no evaluation significance. The more "★" there are, the better the appearance.

[0084] In summary, the powder defoamer prepared by the present invention has a relatively high wet density of the test slurry in self-leveling mortar, few pores and oil spots after hardening, and good compressive strength and aesthetics after hardening.

[0085] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A powder defoamer for self-leveling cement, characterized in that, it is composed of the following components by weight percentage: 10-30% of polyether-modified polyorganosiloxane A, 10-30% of polyether B, 5-20% of environmentally friendly plasticizer C, 0.1-5% of anionic surfactant D, 50-70% of silica E; The polyether-modified polyorganosiloxane A is composed of the following basic units: R a R b 1 SiO (3-a-b) / 2 ; where a represents a natural number from 1 to 2, b represents a natural number from 0 to 2, R is selected from methyl and phenyl, and R 1 is selected from methyl and -CH 2 CH 2 CH 2 (CH 2 CH 2 O) c (CH 2 CHCH 3 O) d R 2 , where c represents a natural number from 0 to 15, d represents a natural number from 0 to 60, and R 2 is selected from a hydrogen atom or methyl; The structural formula of the polyether B is: R 3 (CH 2 CH 2 O) c (CH 2 CHCH 3 O) d R 2 , where c represents a natural number from 0 to 15, and d represents a natural number from 0 to 60; R 2 is selected from a hydrogen atom or a methyl group, and R 3 is a hydrogen atom or a hydrocarbon group with 1 to 18 carbon atoms; The environmentally friendly plasticizer C is selected from one of tributyl citrate, tributyl acetylcitrate and epoxidized soybean oil.

2. The powder defoamer for self-leveling cement according to claim 1, characterized in that, it is composed of the following components by weight percentage: 10-14% of polyether-modified polyorganosiloxane A, 25-30% of polyether B, 5-10% of environmentally friendly plasticizer C, 0.1-1% of anionic surfactant D, 50-54.9% of silica E.

3. The powder defoamer for self-leveling cement according to claim 1, characterized in that, it is composed of the following components by weight percentage: 14% of polyether-modified polyorganosiloxane A, 25% of polyether B, 10% of environmentally friendly plasticizer C, 1% of anionic surfactant D, 50% of silica E.

4. The powder defoamer for self-leveling cement according to claim 1, characterized in that, the anionic surfactant D is a sulfonate-type anionic surfactant, and is selected from one of sulfofatty acid alkyl ester salts, olefin sulfonates, alkane sulfonates and linear alkylbenzene sulfonates.

5. The powder defoamer for self-leveling cement according to claim 1, characterized in that, The silica E is hydrophilic silica, and its specific surface area is 50 to 500 m 2 / g.

6. A preparation method of the powder defoamer for self-leveling cement according to any one of claims 1-5, characterized in that, Mix polyether-modified polyorganosiloxane A, polyether B, environmentally friendly plasticizer C, and anionic surfactant D evenly to obtain a mixture M, and add M to silica E and stir and mix evenly to obtain a powder-type defoamer product.

7. The application of the powder defoamer for self-leveling cement according to any one of claims 1-5 in defoaming self-leveling cement.

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