White latex and preparation method thereof

Abstract

The invention relates to a white latex and a preparation method thereof, on the basis of using vinyl acetate and butyl acrylate, a modified polyurethane polymer is added as an auxiliary agent, the molecular structure of the modified polyurethane polymer simultaneously contains a hydrophilic group and a hydrophobic group, and the hydrophilic group and the hydrophobic group can be used as an auxiliary agent. Due to the amphiphobic property, micelles can be formed in an aqueous solution, when the concentration of the auxiliary agent is within a certain range, hydrophobic groups can be gathered together to form micelles, and the micelles interact with water molecules through hydrophobic groups and hydrogen bonds, so that the viscosity of the solution is increased; the micelles, vinyl acetate and butyl acrylate polymer particles form a net structure through a cross-linking effect, the molecular weight of the emulsion is increased through the net cross-linking structure, and the viscosity of the polymer is further increased; the white latex disclosed by the invention can prevent a sagging phenomenon in a construction process, and can keep relatively high viscosity in a static state.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a white latex and a preparation method thereof. Background Art

[0002] White latex is a thermoplastic glue that is easy to use, has strong bonding strength, stable production process and low production cost. It is widely used in wood processing, handicrafts, paper, cloth, leather, coatings and other industries.

[0003] For example, CN201310650480.1, "An Improved Plywood Adhesive," discloses a solution composed of the following raw materials in parts by weight: 2.5-4 parts ethylene-vinyl acetate copolymer, 2-3.5 parts white latex, 2.3-4 parts defatted miscellaneous meal powder, 0.6-1.2 parts hydrochloric acid, 2.5-4 parts nano-silica, 2.3-4.2 parts aqueous isocyanate, 1.2-2.4 parts xylene, and 2-4 parts nonylphenol polyoxyethylene ether. CN201810589087.9, "A White Glue for Rattan Crafts," discloses a solution composed of the following ingredients: polyvinyl alcohol, 37% formaldehyde, modified nano-attapulgite, casein, an emulsifier, rosin resin, glycidylamine-type epoxy resin, zinc borate, a stabilizer, a defoamer, a catalyst, and deionized water.

[0004] All of the above adhesives significantly improve bonding performance. However, existing technologies for these adhesives typically increase their solids content. CN201310650480.1 increases the solids content by adding defatted meal powder and nano-silica, while CN201810589087.9 increases the solids content of white latex by adding modified nano-attapulgite. While increasing the solids content improves bonding performance, it also causes the white latex to sag, affecting its overall performance. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a white latex which can improve viscosity and reduce sagging problem while maintaining solid content, in view of the current status of the existing technology.

[0006] The second technical problem to be solved by the present invention is to provide a preparation method of the above-mentioned white latex in view of the current status of the existing technology.

[0007] The technical solution adopted by the present invention to solve at least one of the above technical problems is:

[0008] A white latex, comprising the following components by weight:

[0009] 70-75 parts of deionized water,

[0010] Polyvinyl alcohol 24-88 6-10 parts,

[0011]

[0012] The auxiliary agent is a modified polyurethane polymer.

[0013] In the present invention, the auxiliary agent is U465A. The auxiliary agent U465A forms micelles in an aqueous solution. The micelles form a network structure through cross-linking with the vinyl acetate and butyl acrylate. This network cross-linked structure increases the molecular weight of the emulsion, further increasing the viscosity of the polymer, making the polymer emulsion more viscous and more sticky.

[0014] Preferably, the amount of the additive U465A is 1-3 parts. When the amount of the additive is controlled within this range, the hydrophobic groups in the additive U465A will aggregate to form micelles, which interact with water molecules through hydrophobic group interactions and hydrogen bonds, thereby increasing the viscosity of the solution.

[0015] More preferably, the mass ratio of the additive U465A to vinyl acetate and butyl acrylate is 1:(3-10):(0.5-1). Such parameters are adopted so that the micelles formed by the additive U465A in the aqueous solution can form a network structure with the vinyl acetate and butyl acrylate polymer particles through cross-linking.

[0016] Preferably, the fungicide is a mixture of ACTICIDE LA 1209 and ACTICIDE BAC 50M. The amount of ACTICIDE LA 1209 added is 0.01 to 0.5 parts, and the amount of ACTICIDE BAC 50M added is 0.01 to 0.5 parts.

[0017] A preparation method of white latex comprises the following steps:

[0018] (1) Weighing each component according to the formula; adding deionized water and a portion of polyvinyl alcohol 24-88 into a four-necked flask, stirring and heating, controlling the temperature at 86-90°C, cooling to 74-78°C after the polyvinyl alcohol 24-88 is completely dissolved, adding sodium dodecyl diphenyl ether disulfonate and sodium acetate, stirring for 10 minutes, and performing emulsion polymerization;

[0019] (2) adding a mixture of vinyl acetate and butyl acrylate dropwise over a period of 3.5 to 4 hours. While the mixture is being added, an aqueous solution of ammonium persulfate (3% aqueous solution) is added dropwise, and the addition of the aqueous solution of ammonium persulfate is controlled to be completed over a period of 4 to 4.5 hours.

[0020] (3) Adding auxiliary agent U465A, keeping warm at 85-90°C for 1-1.2 hours; after the insulation is completed, adding glycerin, stirring for 25-60 minutes, adding another part of the dissolved polyvinyl alcohol 24-88 solution (9% aqueous solution), stirring for 1-1.5 hours, cooling to 40-45°C, adding ACTICIDE LA1209 and ACTICIDE BAC 50M, and stirring evenly to obtain the white latex.

[0021] Compared with the prior art, the present invention has the following advantages: on the basis of using vinyl acetate and butyl acrylate, the present invention further adds a modified polyurethane polymer as an auxiliary agent. The molecular structure of the modified polyurethane polymer contains both hydrophilic and hydrophobic groups. This amphiphilic property enables it to form micelles in an aqueous solution. When the concentration of the auxiliary agent is within a certain range, the hydrophobic groups aggregate to form micelles. These micelles interact with water molecules through the interaction of the hydrophobic groups and hydrogen bonds, thereby increasing the viscosity of the solution. At the same time, the micelles form a network structure with the vinyl acetate and butyl acrylate polymer particles through cross-linking. This network cross-linked structure increases the molecular weight of the emulsion, further increasing the viscosity of the polymer.

[0022] In addition, the additive enables the polymer emulsion to have good viscosity stability and anti-biodegradability through the above-mentioned cross-linking reaction, and at the same time has low thixotropy. The viscosity of the emulsion will decrease at a high shear rate, but the viscosity will recover at a low shear rate. This characteristic enables the emulsion to prevent sagging during the construction process and maintain a high viscosity in a static state. DETAILED DESCRIPTION

[0023] The present invention is described in further detail below with reference to the examples.

[0024] Example 1:

[0025] By weight, the white latex of the present embodiment comprises the following components:

[0026]

[0027] The additive U465A was purchased from Shanghai Motian Chemical Co., Ltd.

[0028] The preparation method of above-mentioned white latex is:

[0029] (1) Deionized water and a portion (5.0 parts) of polyvinyl alcohol 24-88 were added to a four-necked flask, stirred and heated at 86-90° C. After the polyvinyl alcohol 24-88 was completely dissolved, the temperature was lowered to 74-78° C., sodium dodecyl diphenyl ether disulfonate and sodium acetate were added, and stirred for 10 minutes to carry out emulsion polymerization;

[0030] (2) adding a mixture of vinyl acetate and butyl acrylate dropwise over 3.5 hours. While adding the mixture, begin adding an aqueous solution of ammonium persulfate (3% aqueous solution) dropwise over 4 hours.

[0031] (3) Add the additive U465A and keep warm at 85-90°C for 1 hour; after the heat preservation is completed, add glycerin, stir for 30 minutes, add 3 parts of the dissolved polyvinyl alcohol 24-88 solution (9% aqueous solution), stir for 1 hour, cool to 40-45°C, add ACTICIDE LA1209 and ACTICIDE BAC 50M, and stir evenly to obtain white latex.

[0032] Example 2:

[0033] By weight, the white latex of the present embodiment comprises the following components:

[0034]

[0035] The additive U465A was purchased from Shanghai Motian Chemical Co., Ltd.

[0036] The preparation method of the above-mentioned white latex is consistent with that of Example 1.

[0037] Example 3:

[0038] By weight, the white latex of the present embodiment comprises the following components:

[0039]

[0040] The additive U465A was purchased from Shanghai Motian Chemical Co., Ltd.

[0041] The preparation method of the above-mentioned white latex is consistent with that of Example 1.

[0042] Comparative Example 1:

[0043] Compared with Example 1, this comparative example only eliminates the use of the auxiliary agent U465A.

[0044] Comparative Example 2:

[0045] Compared with Example 1, the amount of auxiliary agent U465A used in this comparative example is 5 parts.

[0046] Comparative Example 3:

[0047] Compared with Example 1, the usage amount of the auxiliary agent U465A in this comparative example is 0.5 parts.

[0048] The performance of the white latex obtained in Example 1 of the present invention and the comparative examples was tested.

[0049]

Claims

1. A white latex, characterized in that: By weight, it includes the following components The auxiliary agent is a modified polyurethane polymer.

2. The white latex according to claim 1, wherein: The auxiliary agent is U465A.

3. The white latex according to claim 2, wherein: The addition amount of the auxiliary agent U465A is 1-3 parts.

4. The white latex according to claim 2, wherein: The auxiliary agent U465A forms micelles in an aqueous solution, and the micelles form a network structure with the vinyl acetate and butyl acrylate through cross-linking.

5. The white latex according to claim 4, characterized in that: The mass ratio of the auxiliary agent U465A to vinyl acetate and butyl acrylate is 1:(3-10):(0.5-1).

6. The white emulsion according to any one of claims 1 to 5, characterized in that: The fungicide is a mixture of ACTICIDELA 1209 and ACTICIDE BAC 50M.

7. The white latex according to claim 6, characterized in that: The addition amount of the ACTICIDE LA 1209 is 0.01 to 0.5 parts, and the addition amount of the ACTICIDE BAC 50M is 0.01 to 0.5 parts.

8. A method for preparing the white latex according to any one of claims 1 to 7, characterized in that The following steps are involved: (1) Weighing each component according to the formula; adding deionized water and a portion of polyvinyl alcohol 24-88 into a four-necked flask, stirring and heating, controlling the temperature at 86-90°C, cooling to 74-78°C after the polyvinyl alcohol 24-88 is completely dissolved, adding sodium dodecyl diphenyl ether disulfonate and sodium acetate, stirring for 10 minutes, and performing emulsion polymerization; (2) adding a mixture of vinyl acetate and butyl acrylate dropwise over a period of 3.5 to 4 hours. While the mixture is being added, an aqueous solution of ammonium persulfate (3% aqueous solution) is added dropwise, and the addition of the aqueous solution of ammonium persulfate is controlled to be completed over a period of 4 to 4.5 hours. (3) Add additive U465A and keep warm at 85-90°C for 1-1.2 hours; After the insulation is completed, glycerol is added and stirred for 25 to 60 minutes. Then, 3 parts of the dissolved polyvinyl alcohol 24-88 solution (9% aqueous solution) are added. After stirring for 1 to 1.5 hours, the mixture is cooled to 40 to 45° C., ACTICIDE LA1209 and ACTICIDE BAC 50M are added, and the mixture is stirred evenly to obtain the white latex.

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