Carboxylic butadiene-styrene latex and preparation method thereof

Abstract

The invention relates to the technical field of carboxylic butadiene-styrene latex, in particular to carboxylic butadiene-styrene latex and a preparation method thereof.The preparation method comprises the steps that an emulsifying agent, an alkaline agent and deionized water are injected into a reaction kettle, heated and evenly stirred, and premixed liquid is obtained; butadiene, styrene, acrylic acid, a performance additive, layer structure repairing particles, sepiolite and an initiator are added into the premixed solution, and continuous stirring reaction is performed; and after the reaction is finished, carrying out degassing and cooling treatment to obtain the carboxylic butadiene-styrene latex. The layer structure repairing particles and the sepiolite are used in a combined manner, so that the water resistance, the tensile property and the bonding property of the carboxylic butadiene-styrene latex are greatly improved. Specifically, under the joint cooperation of the sepiolite with a fibrous crystal structure and the layer structure repairing particles with a granular structure, a cross-linked network with a reinforced structure is formed in the adhesive film, and the layer structure repairing particles can also be filled in pores formed when the adhesive film is cured, so that the compactness of the adhesive film is improved.

Description

Technical Field

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

[0002] Latex is a colloidal emulsion of polymer particles dispersed in water. It can be used directly in surface coatings, thin films, and adhesives, and is widely used in daily life. Latex can be divided into two categories: natural latex and synthetic latex. Natural latex is characterized by strong cohesion, high self-adhesion, good film-forming properties, and adjustable viscosity. However, due to the low polarity of its macromolecular chains, it exhibits poor adhesion to highly polar substrates and relatively poor resistance to aging, oil, chemical, temperature, and frost.

[0003] Carboxylated styrene butadiene latex (SBR) is a copolymer formed by emulsion polymerization of butadiene, styrene, a small amount of carboxylic acid, and other additives. The introduction of carboxyl groups into SBR increases its polarity and improves its adhesive properties. However, SBR shrinks during drying and curing, which can easily form pores or cracks within the latex, seriously affecting the quality of the film. Therefore, a carboxylated styrene butadiene latex and a method for its preparation are proposed. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a carboxylated styrene butadiene latex and a preparation method thereof, which uses layer structure repair particles and sepiolite in combination to greatly improve the water resistance, tensile strength and bonding properties of the carboxylated styrene butadiene latex.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a carboxylated styrene-butadiene latex, comprising the following raw materials in parts by weight: 70-80 parts of butadiene, 15-25 parts of styrene, 3-5 parts of acrylic acid, 2-3 parts of a modification aid, 3-6 parts of layer structure repair particles, 1-2 parts of sepiolite, 2-4 parts of an emulsifier, 0.5-2 parts of an initiator, 0.5-1 parts of an alkali agent, and 100-130 parts of deionized water.

[0006] Preferably, the emulsifier is selected from potassium dodecylbenzenesulfonate and sodium dodecylbenzenesulfonate; the initiator is selected from ammonium persulfate and potassium persulfate; and the alkali agent is selected from sodium hydroxide.

[0007] Preferably, the modification aid comprises acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1:(1-1.5).

[0008] Preferably, the preparation method of the layer structure repair particles is as follows: S1. Immerse mesoporous nano-silica in linseed oil, ultrasonically oscillate for 2-3 hours, and filter to obtain nanoparticles with linseed oil as the core and mesoporous nano-silica as the supporting skeleton; S2. Stir and dissolve ethyl cellulose in anhydrous ethanol to obtain a protective liquid; S3. Evenly spray the protective liquid on the surface of the nanoparticles, and after drying, form a protective film layer on the surface of the nanoparticles to obtain layer structure repair particles.

[0009] Preferably, in step S1, the preparation method of the mesoporous nano-silica is as follows: adding hexadecyltrimethylammonium chloride to a 0.2wt% sodium hydroxide solution, stirring in a water bath at 75-80°C for 2-2.5h; continuing to add ethyl orthosilicate, stirring for 3-4h; then refluxing with ethanol hydrochloric acid solution for 4-5h, and then centrifuging, washing and drying to obtain mesoporous nano-silica.

[0010] Preferably, the mass ratio of the hexadecyltrimethylammonium chloride to the sodium hydroxide solution is 1:(400-500).

[0011] Preferably, the mass ratio of hexadecyltrimethylammonium chloride to ethyl orthosilicate is 1:(6-10).

[0012] Preferably, in step S2, the mass ratio of the ethyl cellulose to anhydrous ethanol is 1:(10-15).

[0013] The present invention also provides a method for preparing carboxylated styrene-butadiene latex, comprising the following steps: (1) Inject the emulsifier, alkali agent and deionized water into the reactor, heat and stir evenly to obtain a premixed solution; (2) Add butadiene, styrene, acrylic acid, modification additive, layer structure repair particles, sepiolite and initiator to the premixed solution and continue stirring to react; (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0014] Preferably, in step (1), the temperature is raised to 80-90°C; in step (2), the reaction is continued at 85-95°C with stirring for 3-4 hours.

[0015] The present invention provides a carboxylated styrene-butadiene latex and a preparation method thereof, which have the following beneficial effects compared with the prior art: The present invention combines layered structure-repairing particles with sepiolite to significantly improve the water resistance, tensile strength, and adhesive properties of carboxylated styrene-butadiene latex. Specifically, the fibrous crystalline structure of sepiolite and the granular layered structure-repairing particles work together to form a reinforced cross-linked network within the film. Furthermore, the layered structure-repairing particles can fill pores formed during film curing, enhancing the film's compactness.

[0016] The layered structure repair particles of the present invention use mesoporous nano-silica as a skeleton, linseed oil is coated inside, and a protective film layer is formed outside for protection. When the latex liquid dries and shrinks or is squeezed by external force, the protective film layer breaks, and the linseed oil flows out of the mesoporous nano-silica to fill and repair the pores or cracks, thereby maintaining the continuity and density of the film and improving the water resistance and strength of the film.

[0017] The present invention further adds acrylonitrile and N-hydroxymethyl acrylamide as modification aids, introduces nitrile groups and amide groups, and further improves the adhesive force and stability of the latex. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is a schematic diagram of the layer structure repair particle structure of the present invention; Figure 2 This is a cross-sectional micrograph of the cured film of carboxylated styrene butadiene latex in Example 6 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0019] The following examples illustrate the implementation methods of the present application in detail, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0020] Example 1 The preparation method of the layer structure repair particles is as follows: S1, immersing mesoporous nano-silica in linseed oil, ultrasonically oscillating for 3 hours, and filtering to obtain nanoparticles with linseed oil as the core and mesoporous nano-silica as the supporting skeleton; The mesoporous nano-silica was prepared as follows: cetyltrimethylammonium chloride was added to a 0.2wt% sodium hydroxide solution at a mass ratio of 1:400, and the mixture was stirred in a water bath at 80°C for 2 hours. Ethyl orthosilicate was then added and stirred for 4 hours. The mixture was then refluxed with an ethanolic hydrochloric acid solution for 4 hours, followed by centrifugation, washing, and drying to produce the mesoporous nano-silica. The mass ratio of cetyltrimethylammonium chloride to ethyl orthosilicate was 1:10.

[0021] S2. Dissolve ethyl cellulose in anhydrous ethanol at a mass ratio of 1:10 by stirring to obtain a protective solution.

[0022] S3. Spraying the protective liquid evenly on the surface of the nanoparticles, forming a protective film layer on the surface of the nanoparticles after drying, and obtaining layer structure repair particles.

[0023] Example 2 The preparation method of the layer structure repair particles is as follows: S1, immersing mesoporous nano-silica in linseed oil, ultrasonically oscillating for 2 hours, and filtering to obtain nanoparticles with linseed oil as the core and mesoporous nano-silica as the supporting skeleton; The mesoporous nano-silica was prepared as follows: cetyltrimethylammonium chloride was added to a 0.2wt% sodium hydroxide solution at a mass ratio of 1:500, and the mixture was stirred in a water bath at 75°C for 2.5 hours. Ethyl orthosilicate was then added and stirred for 3 hours. The mixture was then refluxed with an ethanolic hydrochloric acid solution for 5 hours, followed by centrifugation, washing, and drying to produce the mesoporous nano-silica. The mass ratio of cetyltrimethylammonium chloride to ethyl orthosilicate was 1:6.

[0024] S2. Dissolve ethyl cellulose in anhydrous ethanol at a mass ratio of 1:15 by stirring to obtain a protective solution.

[0025] S3. Spraying the protective liquid evenly on the surface of the nanoparticles, forming a protective film layer on the surface of the nanoparticles after drying, and obtaining layer structure repair particles.

[0026] Example 3 The preparation method of the layer structure repair particles is as follows: S1, immersing mesoporous nano-silica in linseed oil, ultrasonically oscillating for 3 hours, and filtering to obtain nanoparticles with linseed oil as the core and mesoporous nano-silica as the supporting skeleton; The mesoporous nano-silica was prepared as follows: cetyltrimethylammonium chloride was added to a 0.2wt% sodium hydroxide solution at a mass ratio of 1:450, and the mixture was stirred in a water bath at 80°C for 2.5 hours. Ethyl orthosilicate was then added and stirred for 3.5 hours. The mixture was then refluxed with an ethanolic hydrochloric acid solution for 4.5 hours, followed by centrifugation, washing, and drying to produce the mesoporous nano-silica. The mass ratio of cetyltrimethylammonium chloride to ethyl orthosilicate was 1:8.

[0027] S2. Dissolve ethyl cellulose in anhydrous ethanol at a mass ratio of 1:12 by stirring to obtain a protective solution.

[0028] S3. Spraying the protective liquid evenly on the surface of the nanoparticles, forming a protective film layer on the surface of the nanoparticles after drying, and obtaining layer structure repair particles.

[0029] Example 4 A carboxylated styrene-butadiene latex comprises the following raw materials in parts by weight: 80 parts of butadiene, 15 parts of styrene, 5 parts of acrylic acid, 2 parts of a modification aid, 6 parts of layer structure repair particles, 1 part of sepiolite, 4 parts of an emulsifier (sodium dodecylbenzenesulfonate), 0.5 parts of an initiator (ammonium persulfate), 1 part of an alkali agent (sodium hydroxide), and 100 parts of deionized water.

[0030] The modification aid includes acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1:1.5.

[0031] The preparation method of the above-mentioned carboxylated styrene-butadiene latex comprises the following steps: (1) Inject emulsifier, alkali agent and deionized water into the reactor, heat to 80℃ and stir evenly to obtain a premixed solution.

[0032] (2) Add butadiene, styrene, acrylic acid, modification additive, layer structure repair particles, sepiolite and initiator to the premixed solution and continue stirring at 95°C for 3 hours.

[0033] (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0034] In this embodiment, the layered structure repair particles prepared in Example 1 were used.

[0035] Example 5 A carboxylated styrene-butadiene latex comprises the following raw materials in parts by weight: 70 parts of butadiene, 25 parts of styrene, 3 parts of acrylic acid, 3 parts of a modification aid, 3 parts of layer structure repair particles, 2 parts of sepiolite, 2 parts of an emulsifier (potassium dodecylbenzenesulfonate), 2 parts of an initiator (potassium persulfate), 0.5 parts of an alkali agent (sodium hydroxide), and 130 parts of deionized water.

[0036] The modification aid includes acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1:1.

[0037] The preparation method of the above-mentioned carboxylated styrene-butadiene latex comprises the following steps: (1) Inject emulsifier, alkali agent and deionized water into the reactor, heat to 90℃ and stir evenly to obtain a premixed solution.

[0038] (2) Add butadiene, styrene, acrylic acid, modification additive, layer structure repair particles, sepiolite and initiator to the premixed solution and continue stirring at 85°C for 4 hours.

[0039] (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0040] In this embodiment, the layered structure repair particles prepared in Example 2 were used.

[0041] Example 6 A carboxylated styrene-butadiene latex comprises the following raw materials in parts by weight: 75 parts of butadiene, 20 parts of styrene, 4 parts of acrylic acid, 3 parts of a modification aid, 5 parts of layer structure repair particles, 2 parts of sepiolite, 3 parts of an emulsifier (sodium dodecylbenzenesulfonate), 1 part of an initiator (potassium persulfate), 0.8 parts of an alkali agent (sodium hydroxide), and 115 parts of deionized water.

[0042] The modification aid includes acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1:1.

[0043] The preparation method of the above-mentioned carboxylated styrene-butadiene latex comprises the following steps: (1) Inject emulsifier, alkali agent and deionized water into the reactor, heat to 85℃ and stir evenly to obtain a premixed solution.

[0044] (2) Add butadiene, styrene, acrylic acid, modification additive, layer structure repair particles, sepiolite and initiator to the premixed solution, and continue stirring at 90°C for 4 hours.

[0045] (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0046] In this embodiment, the layered structure repair particles prepared in Example 3 were used.

[0047] Comparative Example 1 A carboxylated styrene-butadiene latex comprises the following raw materials in parts by weight: 75 parts of butadiene, 20 parts of styrene, 4 parts of acrylic acid, 3 parts of a modifying auxiliary agent, 2 parts of sepiolite, 3 parts of an emulsifier (sodium dodecylbenzenesulfonate), 1 part of an initiator (potassium persulfate), 0.8 part of an alkali agent (sodium hydroxide), and 115 parts of deionized water.

[0048] The modification aid includes acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1:1.

[0049] The preparation method of the above-mentioned carboxylated styrene-butadiene latex comprises the following steps: (1) Inject emulsifier, alkali agent and deionized water into the reactor, heat to 85℃ and stir evenly to obtain a premixed solution.

[0050] (2) Add butadiene, styrene, acrylic acid, modification agent, sepiolite and initiator to the premixed solution and continue stirring at 90°C for 4 hours.

[0051] (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0052] Comparative Example 2 A carboxylated styrene-butadiene latex comprises the following raw materials in parts by weight: 75 parts of butadiene, 20 parts of styrene, 4 parts of acrylic acid, 3 parts of a modification aid, 5 parts of layer structure repair particles, 3 parts of an emulsifier (sodium dodecylbenzenesulfonate), 1 part of an initiator (potassium persulfate), 0.8 parts of an alkali agent (sodium hydroxide), and 115 parts of deionized water.

[0053] The modification aid includes acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1:1.

[0054] The preparation method of the above-mentioned carboxylated styrene-butadiene latex comprises the following steps: (1) Inject emulsifier, alkali agent and deionized water into the reactor, heat to 85℃ and stir evenly to obtain a premixed solution.

[0055] (2) Add butadiene, styrene, acrylic acid, modification additive, layer structure repair particles and initiator to the premixed solution, and continue stirring at 90°C for 4 hours.

[0056] (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0057] In this comparative example, the layered structure repair particles prepared in Example 3 were used.

[0058] Comparative Example 3 A carboxylated styrene-butadiene latex comprises the following raw materials in parts by weight: 75 parts of butadiene, 20 parts of styrene, 4 parts of acrylic acid, 5 parts of layer structure repair particles, 2 parts of sepiolite, 3 parts of an emulsifier (sodium dodecylbenzenesulfonate), 1 part of an initiator (potassium persulfate), 0.8 parts of an alkali agent (sodium hydroxide), and 115 parts of deionized water.

[0059] The preparation method of the above-mentioned carboxylated styrene-butadiene latex comprises the following steps: (1) Inject emulsifier, alkali agent and deionized water into the reactor, heat to 85℃ and stir evenly to obtain a premixed solution.

[0060] (2) Add butadiene, styrene, acrylic acid, layered structure repair particles, sepiolite and initiator to the premixed solution and continue stirring at 90°C for 4 hours.

[0061] (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

[0062] In this comparative example, the layered structure repair particles prepared in Example 3 were used.

[0063] Comparative Example 4 It is basically the same as Example 5, except that the modification aid only contains acrylonitrile.

[0064] Comparative Example 5 The method is basically the same as Example 5, except that the modification aid only contains N-hydroxymethyl acrylamide.

[0065] Quality Inspection 1. The carboxylated styrene-butadiene latex in Examples 4-6 and Comparative Examples 1-5 was used as a sample for testing.

[0066] Water absorption test. The carboxylated styrene butadiene latex sample was poured into a mold and solidified into a film, which was then weighed and recorded as , let it stand for 6 hours and then soak it in deionized water for 72 hours. After taking it out, wipe off the surface moisture and weigh it. , water absorption The calculation formula is as follows: .

[0067] Mechanical properties test: The carboxylated styrene butadiene latex sample was poured into a mold and cured to form a film. After standing for 6 hours, the film was tested at room temperature using an electronic tensile testing machine according to GB / T528-2009 standard, with a tensile speed set at 10 mm / min.

[0068] The specific test results are shown in Table 1.

[0069] Table 1 Water absorption and mechanical properties

[0070] As shown in Table 1: (1) Compared with Example 6, the sample in Comparative Example 1 did not use layered structure repair particles, resulting in poor water resistance and tensile strength.

[0071] (2) Compared with Example 6, the sample in Comparative Example 2 did not use sepiolite, and its water resistance performance was still good, but its tensile strength decreased significantly.

[0072] (3) Compared with Example 6, in Comparative Example 3, no acrylonitrile and N-hydroxymethyl acrylamide were used, while in Comparative Examples 4 and 5, only acrylonitrile or N-hydroxymethyl acrylamide was used. The water resistance and tensile strength of the obtained samples were slightly reduced.

[0073] 2. The carboxylated styrene-butadiene rubber latexes in Example 6 and Comparative Examples 1-5 were used as samples for testing.

[0074] Peel strength test: A sample of carboxylated styrene-butadiene latex was applied to a glass surface and allowed to solidify into a film. After standing for 6 hours, the film was tested according to GB / T 7142-2008. The specific test results are shown in Table 2.

[0075] Table 2 Peel strength

[0076] As shown in Table 2: (1) Compared with Example 6, the peel strength of the samples in Comparative Examples 1 and 2 is relatively low, indicating that the use of layer structure repair particles and sepiolite can indeed improve the adhesion of carboxylated styrene butadiene latex.

[0077] (2) Compared with Example 6, in Comparative Example 3, no acrylonitrile and N-hydroxymethyl acrylamide were used, while in Comparative Examples 4 and 5, only acrylonitrile or N-hydroxymethyl acrylamide was used. The peel strength was slightly reduced, indicating that acrylonitrile and N-hydroxymethyl acrylamide have a positive effect on improving the adhesion of carboxylated styrene butadiene latex.

[0078] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A carboxylated styrene-butadiene latex, characterized in that: The method comprises the following raw materials in parts by weight: 70-80 parts of butadiene, 15-25 parts of styrene, 3-5 parts of acrylic acid, 2-3 parts of modification auxiliary agent, 3-6 parts of layer structure repair particles, 1-2 parts of sepiolite, 2-4 parts of emulsifier, 0.5-2 parts of initiator, 0.5-1 parts of alkali agent and 100-130 parts of deionized water.

2. Carboxylated styrene-butadiene latex according to claim 1, characterized in that, The emulsifier is selected from potassium dodecylbenzenesulfonate and sodium dodecylbenzenesulfonate; the initiator is selected from ammonium persulfate and potassium persulfate; and the alkali agent is selected from sodium hydroxide.

3. Carboxylated styrene-butadiene latex according to claim 1, characterized in that, The modification auxiliary agent includes acrylonitrile and N-hydroxymethyl acrylamide, and the mass ratio of acrylonitrile to N-hydroxymethyl acrylamide is 1: (1-1.5).

4. Carboxylated styrene-butadiene latex according to claim 1, characterized in that The preparation method of the layer structure repair particles is as follows: S1. Immersing mesoporous nano-silica in linseed oil, ultrasonically oscillating for 2-3 hours, and filtering to obtain nanoparticles with linseed oil as the core and mesoporous nano-silica as the supporting skeleton; S2. stirring and dissolving ethyl cellulose in anhydrous ethanol to obtain a protective solution; S3. Spraying the protective liquid evenly on the surface of the nanoparticles, forming a protective film layer on the surface of the nanoparticles after drying, and obtaining layer structure repair particles.

5. Carboxylated styrene-butadiene latex according to claim 4, characterized in that, In step S1, the preparation method of the mesoporous nano-silica is as follows: cetyltrimethylammonium chloride is added to a 0.2wt% sodium hydroxide solution, and stirred in a water bath at 75-80°C for 2-2.5 hours; ethyl orthosilicate is continuously added and stirred for 3-4 hours; then, the mixture is refluxed with an ethanolic hydrochloric acid solution for 4-5 hours, and then the mixture is centrifuged, washed, and dried to obtain the mesoporous nano-silica.

6. Carboxylated styrene-butadiene latex according to claim 5, characterized in that The mass ratio of the hexadecyltrimethylammonium chloride to the sodium hydroxide solution is 1:(400-500).

7. The carboxylated styrene-butadiene latex according to claim 5, wherein The mass ratio of hexadecyltrimethylammonium chloride to ethyl orthosilicate is 1:(6-10).

8. Carboxylated styrene-butadiene latex according to claim 4, characterized in that, In step S2, the mass ratio of the ethyl cellulose to anhydrous ethanol is 1:(10-15).

9. The method for preparing the carboxylated styrene-butadiene latex according to any one of claims 1 to 8, wherein: The following steps are involved: (1) Inject the emulsifier, alkali agent and deionized water into the reactor, heat and stir evenly to obtain a premixed solution; (2) Add butadiene, styrene, acrylic acid, modification additive, layer structure repair particles, sepiolite and initiator to the premixed solution and continue stirring to react; (3) After the reaction is completed, the carboxylated styrene-butadiene latex is obtained by degassing and cooling.

10. The method for preparing carboxylated styrene-butadiene latex according to claim 1, wherein In step (1), the temperature is raised to 80-90°C; in step (2), the reaction is continued at 85-95°C with stirring for 3-4 hours.

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