Equipment for producing small-particle-size thermal expansion microspheres

Abstract

The utility model relates to the technical field of thermal expansion microsphere production, and particularly discloses equipment for producing small-particle-size thermal expansion microspheres, which comprises a water phase homogenizing kettle, an oil phase homogenizing kettle, a water-oil phase homogenizing kettle, a centrifugal pump, a primary static mixer, a secondary static mixer, a polymerization kettle, a bypass assembly and a backflow assembly, the water phase homogenizing kettle and the oil phase homogenizing kettle are respectively connected with the water-oil phase homogenizing kettle through pipelines, the water-oil phase homogenizing kettle is connected with the centrifugal pump through a pipeline, the first-stage static mixer is connected with the centrifugal pump through a pipeline, the second-stage static mixer is connected with the first-stage static mixer through a pipeline, and the second-stage static mixer is connected with the second-stage static mixer through a pipeline. The polymerization kettle is connected with the second-stage static mixer through a pipeline, the bypass assembly and the backflow assembly are both connected with the pipeline between the centrifugal pump and the first-stage static mixer, and through the arrangement, the thermal expansion microspheres with better particle size distribution, better expansion performance and lower residual monomer amount can be obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of heat expansion microsphere production, in particular to a device for producing small-diameter heat expansion microspheres. Background Art

[0002] Thermally expandable microspheres are microspheres with a core-shell structure, consisting of a thermoplastic polymer shell and an expandable substance, such as a volatile expansion agent such as aliphatic alkanes. Thermally expandable microspheres have been successfully used as a light and heavy filler in fields such as plasticine, printing paste, plastics and elastomers. In actual production, the particle size of thermally expandable microspheres is polydisperse. When the polydispersity coefficient Span of the particle size of thermally expandable microspheres is large, the expansion performance and product yield of the thermally expandable microspheres will be affected. That is, microspheres with too large or too small particle size have poor expansion performance and the amount of residual monomers in the preparation of microspheres is high. Therefore, it is particularly necessary to reduce the particle size polydispersity coefficient of thermally expandable microspheres.

[0003] At present, the production method of heat-expandable microspheres often adopts the process of homogenous emulsification plus centrifugal pump transfer, which has significant advantages such as simple operation and intermittent production. Due to the limited stirring form and shear capacity of the homogenous emulsification kettle, under certain conditions of the production formula of heat-expandable microspheres, the microsphere particle size is often controlled by centrifugal pump frequency modulation during the transfer process.

[0004] However, in the above-mentioned prior art, the centrifugal pump relies on the rotation of the impeller to shear the material. The turbulence generated by the rotation of the impeller will largely cause the microsphere particle size polydispersity coefficient to be large. The greater the impeller speed, the more severe the turbulence generated, and the larger the particle size polydispersity coefficient of the microspheres. Utility Model Content

[0005] The purpose of the utility model is to provide an apparatus for producing small-particle thermal expansion microspheres, aiming to solve the technical problem in the prior art that a centrifugal pump relies on the rotation of an impeller to shear the material, and the turbulence generated by the rotation of the impeller will largely cause a large polydispersity coefficient of the microsphere particle size. The greater the impeller speed, the more severe the turbulence formed, and the larger the polydispersity coefficient of the microsphere particle size.

[0006] To achieve the above-mentioned purpose, the utility model adopts an apparatus for producing small-particle thermal expansion microspheres, comprising an aqueous phase homogenizing kettle, an oil phase homogenizing kettle, a water-oil phase homogenizing kettle, a centrifugal pump, a primary static mixer, a secondary static mixer, a polymerization kettle, a bypass assembly and a reflux assembly, wherein the aqueous phase homogenizing kettle and the oil phase homogenizing kettle are respectively connected to the water-oil phase homogenizing kettle via pipelines, the water-oil phase homogenizing kettle is connected to the centrifugal pump via a pipeline, the primary static mixer is connected to the centrifugal pump via a pipeline, the secondary static mixer is connected to the primary static mixer via a pipeline, the polymerization kettle is connected to the secondary static mixer via a pipeline, and the bypass assembly and the reflux assembly are both connected to the pipeline between the centrifugal pump and the primary static mixer.

[0007] Among them, the bypass assembly includes a bypass pipeline and a bypass valve, one end of the bypass pipeline is connected to the pipeline between the centrifugal pump and the first-stage static mixer, the other end of the bypass pipeline is connected to the polymerization kettle, and the bypass valve is arranged on the bypass pipeline.

[0008] Among them, the reflux assembly includes a reflux pipeline and a reflux valve, one end of the reflux pipeline is connected to the pipeline between the centrifugal pump and the first-level static mixer, and the other end of the reflux pipeline is connected to the pipeline between the second-level static mixer and the polymerization kettle.

[0009] The equipment for producing small-size thermally expandable microspheres further comprises two first valves, which are respectively arranged on the pipelines between the water-oil homogenizing kettle and the water-phase homogenizing kettle and the oil-phase homogenizing kettle.

[0010] The equipment for producing small-size thermally expandable microspheres further comprises a second valve, which is arranged on the pipeline between the water-oil phase homogenizing kettle and the centrifugal pump.

[0011] The equipment for producing small-size thermally expandable microspheres further comprises a third valve, which is arranged on the pipeline between the centrifugal pump and the first-stage static mixer.

[0012] The present invention provides an apparatus for producing small-particle thermal expansion microspheres. The material in the water-oil phase homogenization kettle can sequentially pass through the centrifugal pump, the first-stage static mixer, and the second-stage static mixer before entering the polymerization reactor. Alternatively, the material can directly enter the polymerization reactor from a bypass line via the bypass valve. The material that has passed through the first-stage static mixer and the second-stage static mixer can re-enter the first-stage static mixer from a loop line via the reflux valve. This method can effectively solve the problem in the prior art that the centrifugal pump relies on the rotation of the impeller to shear the material, and the turbulence generated by the impeller rotation will largely cause a large polydispersity coefficient of the microsphere particle size. The greater the impeller speed, the more severe the turbulence generated, and the larger the polydispersity coefficient of the microsphere particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 It is a structural diagram of the present utility model.

[0015] 101-water phase homogenizing kettle, 102-oil phase homogenizing kettle, 103-water-oil phase homogenizing kettle, 104-centrifugal pump, 105-first-stage static mixer, 106-second-stage static mixer, 107-polymerization kettle, 108-bypass line, 109-bypass valve, 110-reflux line, 111-reflux valve, 112-first valve, 113-second valve, 114-third valve. DETAILED DESCRIPTION

[0016] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0017] See also Figure 1 ,in Figure 1 It is a structural diagram of the present utility model.

[0018] The first embodiment of this application is:

[0019] In the specific use of the apparatus for producing small-particle thermally expandable microspheres according to this embodiment, after the water homogenizing kettle 101 and the oil homogenizing kettle 102 respectively homogenize the water phase and the oil phase, and after the nitrogen pressure in the water homogenizing kettle 101, the oil homogenizing kettle 102, and the water-oil homogenizing kettle 103 is balanced, the two first valves 112 are fully opened to allow the water phase material in the water homogenizing kettle 101 and the oil phase material in the oil homogenizing kettle 102 to enter the water-oil homogenizing kettle 103 for water-oil emulsification. After the water phase emulsification is completed, the bypass valve 109 is fully opened, the third valve 114 is fully closed, the centrifugal pump 104 is started, and the frequency of the centrifugal pump 104 is set to 30-35 Hz. The second oil valve is then fully opened to transfer the materials. The final particle size polydispersity coefficient Span value obtained is 1.904, and the residual monomer content is 1024 ppm.

[0020] The second embodiment of the present application is:

[0021] In the specific use of the apparatus for producing small-particle heat-expandable microspheres according to this embodiment, after the water homogenizing kettle 101 and the oil homogenizing kettle 102 respectively homogenize the water phase and the oil phase, and after the nitrogen pressure in the water homogenizing kettle 101, the oil homogenizing kettle 102, and the water-oil homogenizing kettle 103 is balanced, the two first valves 112 are fully opened to allow the water phase material in the water homogenizing kettle 101 and the oil phase material in the oil homogenizing kettle 102 to enter the water-oil homogenizing kettle 103 for water-oil emulsification. After the water phase emulsification is completed, the bypass valve 109 is fully closed, the third valve 114 is fully opened, the reflux valve 111 is fully closed, the centrifugal pump 104 is started, and the frequency of the centrifugal pump 104 is set to 30-35 Hz. The second oil valve is then fully opened to transfer the materials. The final particle size polydispersity coefficient Span value is 0.927, and the residual monomer content is 554 ppm.

[0022] The third embodiment of the present application is:

[0023] In the specific use of the apparatus for producing small-particle thermally expandable microspheres according to this embodiment, after the aqueous phase homogenizing kettle 101 and the oil phase homogenizing kettle 102 respectively homogenize the aqueous phase and the oil phase, and after the aqueous phase homogenizing kettle 101, the oil phase homogenizing kettle 102, and the water-oil phase homogenizing kettle 103 complete nitrogen pressure equilibrium, the two first valves 112 are fully opened to allow the aqueous phase material in the aqueous phase homogenizing kettle 101 and the oil phase material in the oil phase homogenizing kettle 102 to enter the water-oil phase homogenizing kettle 103 for water-oil emulsification. After the aqueous phase emulsification is completed, the bypass valve 109 is fully closed, the third valve 114 is fully opened, the opening of the loop valve is controlled to 30%, the centrifugal pump 104 is started, and the frequency of the centrifugal pump 104 is set to 30-35 Hz. Then, the second oil valve is fully opened to transfer the materials. The final particle size polydispersity coefficient Span value obtained is 0.691, and the residual monomer content is 356 ppm.

[0024] The fourth embodiment of the present application is:

[0025] In the specific use of the apparatus for producing small-particle thermally expandable microspheres according to this embodiment, after the aqueous phase homogenizing kettle 101 and the oil phase homogenizing kettle 102 respectively homogenize the aqueous phase and the oil phase, and after the aqueous phase homogenizing kettle 101, the oil phase homogenizing kettle 102, and the water-oil phase homogenizing kettle 103 complete nitrogen pressure equilibrium, the two first valves 112 are fully opened to allow the aqueous phase material in the aqueous phase homogenizing kettle 101 and the oil phase material in the oil phase homogenizing kettle 102 to enter the water-oil phase homogenizing kettle 103 for water-oil emulsification. After the aqueous phase emulsification is completed, the bypass valve 109 is fully closed, the third valve 114 is fully opened, the opening of the loop valve is controlled to 80%, the centrifugal pump 104 is started, and the frequency of the centrifugal pump 104 is set to 30-35 Hz. The second oil valve is then fully opened to transfer the materials. The final particle size polydispersity coefficient Span value obtained is 0.972, and the residual monomer content is 542 ppm.

[0026]

[0027] The beneficial effects of the present application are as follows: the Span value of the microsphere particle size polydispersity coefficient prepared by the first-stage static mixer 105 and the second-stage static mixer 106 is reduced from 1.904 to 0.927, the expansion performance of the microspheres is improved, and the amount of residual monomers is reduced. By controlling the appropriate reflux percentage, thermally expandable microspheres with better particle size distribution, better expansion performance, and lower residual monomer content can be obtained.

[0028] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the utility model.

Claims

1. A device for producing small-size thermally expandable microspheres, characterized in that: The invention comprises an aqueous phase homogenizing kettle, an oil phase homogenizing kettle, a water-oil phase homogenizing kettle, a centrifugal pump, a primary static mixer, a secondary static mixer, a polymerization kettle, a bypass assembly and a reflux assembly. The aqueous phase homogenizing kettle and the oil phase homogenizing kettle are respectively connected to the water-oil phase homogenizing kettle through pipelines, the water-oil phase homogenizing kettle is connected to the centrifugal pump through a pipeline, the primary static mixer is connected to the centrifugal pump through a pipeline, the secondary static mixer is connected to the primary static mixer through a pipeline, the polymerization kettle is connected to the secondary static mixer through a pipeline, and the bypass assembly and the reflux assembly are both connected to the pipeline between the centrifugal pump and the primary static mixer.

2. The device for producing small-size heat-expandable microspheres according to claim 1, wherein: The bypass assembly includes a bypass pipeline and a bypass valve. One end of the bypass pipeline is connected to the pipeline between the centrifugal pump and the first-stage static mixer, and the other end of the bypass pipeline is connected to the polymerization kettle. The bypass valve is arranged on the bypass pipeline.

3. The device for producing small-size heat-expandable microspheres according to claim 2, wherein: The reflux assembly includes a reflux pipeline and a reflux valve. One end of the reflux pipeline is connected to the pipeline between the centrifugal pump and the first-level static mixer, and the other end of the reflux pipeline is connected to the pipeline between the second-level static mixer and the polymerization kettle.

4. The device for producing small-size heat-expandable microspheres according to claim 3, wherein: The equipment for producing small-size thermally expandable microspheres further includes two first valves, which are respectively arranged on the pipelines between the water-oil homogenizing kettle and the water-phase homogenizing kettle and the oil-phase homogenizing kettle.

5. The device for producing small-size heat-expandable microspheres according to claim 4, wherein: The equipment for producing small-diameter thermally expandable microspheres further includes a second valve, which is arranged on the pipeline between the water-oil phase homogenizing kettle and the centrifugal pump.

6. The device for producing small-size heat-expandable microspheres according to claim 5, wherein: The equipment for producing small-diameter thermally expandable microspheres further includes a third valve, which is arranged on the pipeline between the centrifugal pump and the first-stage static mixer.

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