Preparation method of acrylate resin powder

Abstract

The invention belongs to the technical field of plastic processing aids, and particularly provides a preparation method of acrylate resin powder, which comprises the following steps: S1, putting methyl methacrylate, butyl acrylate, an azobenzene bond-containing acrylate monomer, an emulsifier, a cross-linking agent, an electrolyte and deionized water into a reaction kettle, and stirring and emulsifying at a high speed to form a stable pre-emulsion; s2, heating the reaction emulsion, maintaining the temperature at 50-55 DEG C, adding an initiator, and controlling the temperature to react for 3-4 hours; s3, after the temperature-controlled reaction, irradiating the emulsion at intervals through ultraviolet rays with the wavelength of 365 nanometers, maintaining the temperature at 50-55 DEG C, and reacting to obtain acrylate emulsion; and S4, adding calcium chloride accounting for 1% of the mass of the acrylate emulsion into the prepared acrylate emulsion for flocculation demulsification, and then washing and drying to obtain acrylate resin powder. The preparation method is sufficient in reaction, and the prepared acrylate resin powder is high in molecular weight.

Description

Technical Field

[0001] This invention relates to the field of plastic processing aids, and more particularly to a method for preparing acrylate resin powder. Background Technology

[0002] In recent years, high molecular weight acrylate polymers have become a common processing aid for polyvinyl chloride, polycarbonate, and polyamide. Their high molecular weight imparts high melt strength and melt flowability to downstream products, resulting in superior performance. For example, international patent WO2018157747A1 describes a method for preparing a high-solids acrylic resin. The resulting acrylic resin has a Grignard viscosity of 15–25 S and a solids content of 70%–75%. In the production of high molecular weight acrylate polymers, to ensure their high molecular weight, a low-temperature, temperature-controlled reaction with high solids content is often employed. However, this method can lead to excessively low reaction conversion rates and excessive residual monomers. Summary of the Invention

[0003] To address the aforementioned deficiencies, this invention provides a method for preparing acrylate resin powder. This method ensures a complete reaction and yields acrylate resin powder with a high molecular weight.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing acrylate resin powder, comprising: S1: Methyl methacrylate, butyl acrylate, acrylate monomers containing azobenzene bonds, emulsifier, crosslinking agent, electrolyte, and deionized water are added to a reaction vessel and emulsified by stirring at 100-200 rpm for 30 minutes to form a stable pre-emulsion. The mass ratio of methyl methacrylate, butyl acrylate, and acrylate monomers containing azobenzene bonds in S1 is 70~80:10~15:10~15, and the acrylate monomers containing azobenzene bonds are selected from either (1-4'-butylazophenoxy-6-hexanol) methacrylate or 11-[4-(4-butylphenylazo)phenoxy]undecyl methacrylate. The emulsifier is selected from either sodium alkyl sulfonate or sodium alkylbenzene sulfonate; the crosslinking agent is selected from either trimethylolpropane triacrylate or pentaerythritol triacrylate; and the electrolyte is selected from either sodium pyrophosphate or sodium metaphosphate. S2: Heat the reaction emulsion and maintain it at 50-55 degrees Celsius, add the initiator, and initially control the temperature for 3-4 hours for the reaction. The initiator includes a reducing agent and an oxidizing agent. The reducing agent is selected from sodium bisulfite or a mixture of sodium bisulfite, ferrous sulfate and ethylenediaminetetraacetic acid. The oxidizing agent is selected from either ammonium persulfate or potassium persulfate. S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 1-3 minutes every 20-30 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 3-4 hours to obtain an acrylic emulsion. S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0005] As a further improvement of the present invention, in S1, based on the total weight of methyl methacrylate, butyl acrylate, and acrylate monomers containing azobenzene bonds, the emulsifier accounts for 2% to 3% of the total weight, the crosslinking agent accounts for 0.8% to 1.2% of the total weight, the electrolyte accounts for 0.1% to 0.14% of the total weight, and the deionized water accounts for 80% to 85% of the total weight; and in S2, the initiator accounts for 0.02% to 0.04% of the total weight.

[0006] As a further improvement of the present invention, the total weight ratio of the reducing agent to the oxidizing agent is 1:1.

[0007] The beneficial effects of this invention are: 1. By introducing acrylate monomers containing azobenzene bonds into the acrylate network structure, the photo-isomerization of azobenzene bonds is utilized to dynamically regulate the cross-linking network during emulsion polymerization. In the early stages of the reaction, the acrylate polymer containing the azobenzene structure forms a cross-linked network structure, at which point the azobenzene structure is a stable trans configuration. As the reaction progresses, the emulsion viscosity increases, and the concentration of residual monomers within the particles decreases. Due to the increased size of the polymer structure within the particles and the resulting greater steric hindrance, the residual monomers find it difficult to continue reacting. Intermittent irradiation of the emulsion with ultraviolet light for a certain period, under the alternating effects of ultraviolet light and reaction heat, causes partial dissociation of the acrylate polymer structure, reducing the steric hindrance within the particles and increasing the reaction probability of the residual monomers. This addresses the problems of low reaction conversion rates and excessively high residual monomer concentrations in the emulsion due to decreased monomer concentrations within the particles and large steric hindrance of the polymer structure in the later stages of high molecular weight emulsion polymerization.

[0008] 2. The special structure of the introduced azobenzene bond can bring photoresponsiveness to plastic products. At present, there are still many problems with ordinary 3D printing technology, such as poor molding effect and complex molding conditions (high temperature, high pressure). The special response of the azobenzene structure to light can be used to repair microcracks and damage generated during 3D printing to a certain extent by using different light intensities and times, while also assisting 3D printing molding. Attached Figure Description

[0009] Figure 1 This is an infrared analysis diagram of the acrylate resin powder prepared according to the present invention. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0011] This invention provides a method for preparing acrylate resin powder, comprising: S1: Methyl methacrylate, butyl acrylate, acrylate monomers containing azobenzene bonds, emulsifier, crosslinking agent, electrolyte and deionized water are added to the reaction vessel and stirred and emulsified at 100-200 rpm for 30 minutes to form a stable pre-emulsion.

[0012] As a further explanation of this embodiment, the mass ratio between methyl methacrylate, butyl acrylate and acrylate monomers containing azobenzene bonds is 70~80:10~15:10~15.

[0013] Based on the total weight percentage of methyl methacrylate, butyl acrylate and acrylate monomers containing azobenzene bonds, the emulsifier accounts for 2% to 3% of the total weight, the crosslinking agent accounts for 0.8% to 1.2% of the total weight, the electrolyte accounts for 0.1% to 0.14% of the total weight, and the deionized water accounts for 80% to 85% of the total weight.

[0014] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add the initiator, and initially control the temperature for 3-4 hours for the reaction.

[0015] As a further explanation of this embodiment, the initiator is 0.02% to 0.04% of the total weight of methyl methacrylate, butyl acrylate and acrylate monomers containing azobenzene bonds in S1.

[0016] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 1-3 minutes every 20-30 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 3-4 hours to obtain an acrylic emulsion.

[0017] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0018] As a further explanation of this embodiment, the acrylate monomer containing the azobenzene bond is selected from either (1-4'-butylazophenoxy-6-hexanol) methacrylate or 11-[4-(4-butylphenylazo)phenoxy]undecyl methacrylate.

[0019] As a further explanation of this embodiment, the emulsifier is selected from either sodium alkyl sulfonate or sodium alkylbenzene sulfonate.

[0020] As a further explanation of this embodiment, the crosslinking agent is selected from either trimethylolpropane triacrylate or pentaerythritol triacrylate.

[0021] As a further explanation of this embodiment, the electrolyte is either sodium pyrophosphate or sodium metaphosphate.

[0022] As a further explanation of this embodiment, the initiator is selected from a water-soluble redox composite initiation system, wherein the reducing agent is selected from sodium bisulfite or a mixture of sodium bisulfite, ferrous sulfate and ethylenediaminetetraacetic acid, and the oxidizing agent is selected from either ammonium persulfate or potassium persulfate, and the total weight ratio of oxidizing agent to reducing agent is 1:1.

[0023] The infrared analysis of the obtained acrylate resin powder is shown in the attached figure in the instruction manual.

[0024] The present invention will be further illustrated below with specific examples, but it should not be construed as the present invention being limited to these examples.

[0025] Where specific experimental steps or conditions are not specified in the examples, they can be performed according to the corresponding conventional experimental steps or conditions in this technical field. All reagents used, unless otherwise specified, are conventional reagents already existing in this field.

[0026] The following examples illustrate the source of raw materials: (1-4'-Butylazophenoxy-6-hexanol) methacrylate, Shanghai Tengzhun Biotechnology Co., Ltd., industrial purity; Methyl methacrylate, Shandong Jinyueyuan New Material Co., Ltd., industrial purity; Butyl acrylate, Shandong Langcheng Chemical Co., Ltd., industrial purity; Sodium dodecyl sulfate, Shandong Yonglida New Material Technology Co., Ltd., industrial purity; Ammonium persulfate, Changzhou Jiaye Chemical Co., Ltd., industrial purity; Sodium bisulfite, Changzhou Jiaye Chemical Co., Ltd., industrial purity; Pentaerythritol triacrylate, Shanghai Yuanye Biotechnology Co., Ltd., industrial purity; Sodium pyrophosphate, Lianyungang Kexin Chemical Co., Ltd., industrial purity.

[0027] Example 1 S1: Add 70 kg of methyl methacrylate, 15 kg of butyl acrylate, 15 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 2 kg of sodium dodecyl sulfate, 0.8 kg of pentaerythritol triacrylate, 0.1 kg of sodium pyrophosphate, and 80 kg of deionized water into a reactor and stir and emulsify at 110 rpm for 30 minutes to form a stable pre-emulsion.

[0028] S2: Heat the reaction emulsion and maintain it at 50-55 degrees Celsius. Add a mixed solution of 0.02 kg ammonium persulfate and 0.02 kg sodium bisulfite. Initially, control the temperature and react for 4 hours.

[0029] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 1 minute every 20 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 4 hours to obtain an acrylic emulsion.

[0030] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0031] Example 2 S1: Add 80 kg of methyl methacrylate, 10 kg of butyl acrylate, 10 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 2 kg of sodium dodecyl sulfate, 0.8 kg of pentaerythritol triacrylate, 0.1 kg of sodium pyrophosphate, and 80 kg of deionized water into a reactor and stir and emulsify at 110 rpm for 30 minutes to form a stable pre-emulsion.

[0032] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.02 kg ammonium persulfate and 0.02 kg sodium bisulfite, and initially control the temperature for 4 hours.

[0033] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 3 minutes every 30 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 4 hours to obtain an acrylic emulsion.

[0034] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0035] Example 3 S1: Add 75 kg of methyl methacrylate, 13 kg of butyl acrylate, 12 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 3 kg of sodium dodecyl sulfate, 1 kg of pentaerythritol triacrylate, 0.1 kg of sodium pyrophosphate, and 82 kg of deionized water into a reactor and stir and emulsify at 120 rpm for 30 minutes to form a stable pre-emulsion.

[0036] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.03 kg ammonium persulfate and 0.03 kg sodium bisulfite, and initially control the temperature for 4 hours.

[0037] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 2 minutes every 25 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 3.5 hours to obtain an acrylic emulsion.

[0038] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0039] Example 4 S1: Add 75 kg of methyl methacrylate, 13 kg of butyl acrylate, 12 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 3 kg of sodium dodecyl sulfate, 1.2 kg of pentaerythritol triacrylate, 0.12 kg of sodium pyrophosphate, and 80 kg of deionized water into a reactor and stir and emulsify at 150 rpm for 30 minutes to form a stable pre-emulsion.

[0040] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.04 kg ammonium persulfate and 0.04 kg sodium bisulfite, and initially control the temperature for 4 hours.

[0041] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 2 minutes every 25 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 4 hours to obtain an acrylic emulsion.

[0042] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0043] Example 5 S1: Add 80 kg of methyl methacrylate, 10 kg of butyl acrylate, 10 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 2.5 kg of sodium dodecyl sulfate, 1.2 kg of pentaerythritol triacrylate, 0.14 kg of sodium pyrophosphate, and 80 kg of deionized water into a reactor and stir and emulsify at 180 rpm for 30 minutes to form a stable pre-emulsion.

[0044] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.03 kg ammonium persulfate and 0.03 kg sodium bisulfite, and initially control the temperature for 3 hours.

[0045] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 2 minutes every 20 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 4 hours to obtain an acrylic emulsion.

[0046] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0047] Example 6 S1: Add 75 kg of methyl methacrylate, 10 kg of butyl acrylate, 15 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 2 kg of sodium dodecyl sulfate, 1 kg of pentaerythritol triacrylate, 0.12 kg of sodium pyrophosphate, and 80 kg of deionized water into a reactor and stir and emulsify at 100 rpm for 30 minutes to form a stable pre-emulsion.

[0048] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.02 kg ammonium persulfate and 0.02 kg sodium bisulfite, and initially control the temperature for 4 hours.

[0049] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 3 minutes every 20 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 4 hours to obtain an acrylic emulsion.

[0050] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0051] Comparative Example 1 S1: Add 80kg of methyl methacrylate, 20kg of butyl acrylate, 2kg of sodium dodecyl sulfate, 0.8kg of pentaerythritol triacrylate, 0.1kg of sodium pyrophosphate, and 80kg of deionized water into a reactor and stir and emulsify at 110rpm for 30 minutes to form a stable pre-emulsion.

[0052] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.02 kg ammonium persulfate and 0.02 kg sodium bisulfite, and stop the reaction after 8 hours to obtain an acrylate emulsion.

[0053] S3: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0054] Comparative Example 2 S1: Add 80 kg of methyl methacrylate, 12 kg of butyl acrylate, 8 kg of (1-4'-butylazophenoxy-6-hexanol) methacrylate, 2 kg of sodium dodecyl sulfate, 0.8 kg of pentaerythritol triacrylate, 0.1 kg of sodium pyrophosphate, and 80 kg of deionized water into a reactor and stir and emulsify at 110 rpm for 30 minutes to form a stable pre-emulsion.

[0055] S2: Heat the reaction emulsion to 50-55 degrees Celsius, add a mixed solution of 0.02 kg ammonium persulfate and 0.02 kg sodium bisulfite, and initially control the temperature for 4 hours.

[0056] S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 2 minutes every 25 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 4 hours to obtain an acrylic emulsion.

[0057] S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

[0058] The acrylate resin emulsions prepared in S3 in Examples 1-6 and Comparative Examples 1-2 were tested as follows.

[0059] Test 1: The residual monomer concentration was detected by gas chromatography. Specifically, an air sample was collected from the dryer during the drying of the emulsion using an activated carbon adsorption collection tube. The sample was then poured into a colorimetric tube to desorb the residual monomer with carbon disulfide, shaken and left to stand for 30 minutes, and then separated using a DB-200 capillary column. The sample was then directly injected for analysis and detected by the FID detector of the gas chromatograph.

[0060] Chromatographic conditions: DB-200 capillary column (30m*0.53mm*1μL); column temperature: 80℃; vaporization chamber temperature: 200℃; detector temperature: 250℃; air flow rate: 400ml / min; hydrogen flow rate: 60ml / min; carrier gas: high-purity nitrogen flow rate: 4.0ml / min; split injection, split ratio: 20:1; injection volume: 1μL.

[0061] The test results of each embodiment and comparative example are shown in the table below:

[0062] As can be seen from the table above, the acrylate resin emulsion prepared by this method has a reduced residual monomer content and a more complete reaction.

[0063] Test 2: The intrinsic viscosity was tested using the Ubbelohde viscosity method. Specifically, the acrylic resin powder was first placed in a 65°C constant temperature oven for 10 hours. After cooling, 0.072 g was accurately weighed using a 0.01% balance and placed in a 25 ml volumetric flask. Then, about 20 ml of chloroform was added to dissolve it. After standing for 24 hours until completely dissolved, the flask was placed in a constant temperature water bath at 25±0.1°C and kept at that temperature for 15 minutes. Then, the flask was diluted to the 25 ml mark with chloroform and filtered through a No. 3 sintered glass funnel before being tested. The viscosity was then measured using an Ubbelohde viscometer, and the viscosity of the chloroform used as a solvent was also measured simultaneously.

[0064] The intrinsic viscosity is calculated as follows:

[0065] Where η is the intrinsic viscosity, η sp It is the specific viscosity, η r It refers to relative viscosity.

[0066] Its calculation method is as follows: η r =t / t0; η sp =η r -1.

[0067] In the formula, t is the time it takes for the plasticizer solution to flow through the capillary, t0 is the time it takes for the solvent chloroform to flow through the same capillary, and c is the concentration of the solution (g / 100ml).

[0068] The test results of each embodiment and comparative example are shown in the table below:

[0069] As can be seen from the table above, the acrylate resin powder prepared by this method has increased intrinsic viscosity and high molecular weight.

[0070] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above-described embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing acrylate resin powder, characterized in that, include: S1: Methyl methacrylate, butyl acrylate, acrylate monomers containing azobenzene bonds, emulsifier, crosslinking agent, electrolyte, and deionized water are added to a reaction vessel and emulsified by stirring at 100-200 rpm for 30 minutes to form a stable pre-emulsion. The mass ratio of methyl methacrylate, butyl acrylate, and acrylate monomers containing azobenzene bonds in S1 is 70~80:10~15:10~15, and the acrylate monomers containing azobenzene bonds are selected from either (1-4'-butylazophenoxy-6-hexanol) methacrylate or 11-[4-(4-butylphenylazo)phenoxy]undecyl methacrylate. The emulsifier is selected from either sodium alkyl sulfonate or sodium alkylbenzene sulfonate; the crosslinking agent is selected from either trimethylolpropane triacrylate or pentaerythritol triacrylate; and the electrolyte is selected from either sodium pyrophosphate or sodium metaphosphate. S2: Heat the reaction emulsion and maintain it at 50-55 degrees Celsius, add the initiator, and initially control the temperature for 3-4 hours for the reaction. The initiator includes a reducing agent and an oxidizing agent. The reducing agent is selected from sodium bisulfite or a mixture of sodium bisulfite, ferrous sulfate and ethylenediaminetetraacetic acid. The oxidizing agent is selected from either ammonium persulfate or potassium persulfate. S3: After the initial temperature-controlled reaction is completed, the emulsion is irradiated with ultraviolet light with a wavelength of 365 nanometers for 1-3 minutes every 20-30 minutes, while maintaining the temperature at 50-55 degrees Celsius. The reaction is stopped after 3-4 hours to obtain an acrylic emulsion. S4: Add 1% (by weight) of calcium chloride to the prepared acrylate emulsion for flocculation and demulsification, then wash and dry to obtain acrylate resin powder.

2. The method for preparing acrylate resin powder according to claim 1, characterized in that, In S1, the emulsifier accounts for 2% to 3% of the total weight of methyl methacrylate, butyl acrylate, and acrylate monomers containing azobenzene bonds, the crosslinking agent accounts for 0.8% to 1.2% of the total weight, the electrolyte accounts for 0.1% to 0.14% of the total weight, and the deionized water accounts for 80% to 85% of the total weight. In S2, the initiator accounts for 0.02% to 0.04% of the total weight.

3. The method for preparing acrylate resin powder according to claim 1, characterized in that, The total weight ratio of the reducing agent to the oxidizing agent is 1:1.

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