A silicone-based RAFT reagent for preparing an acrylate anti-graffiti emulsion and its preparation method

Abstract

The present invention relates to a silicone-based RAFT reagent for preparing an acrylate anti-graffiti emulsion and a preparation method thereof. Using a silicone-based RAFT reagent, methyl methacrylate, hydroxypropyl methacrylate, acrylic acid, and hydroxyethyl acrylate as raw materials, and azobisisobutyronitrile as an initiator, a silicone-containing acrylate polymer emulsifier is prepared by RAFT polymerization under the condition of a temperature of 60-90 °C. Using the silicone-containing acrylate polymer emulsifier, methyl methacrylate, hydroxypropyl methacrylate, isobornyl methacrylate, hydroxyethyl acrylate, styrene, and butyl acrylate as raw materials, and persulfate as an initiator, a silicone-modified acrylate anti-graffiti emulsion is prepared by RAFT polymerization. The anti-graffiti emulsion prepared by the present invention not only has extremely strong adhesion, good scrub resistance and ethanol resistance, but also has excellent storage stability, weather resistance and chemical resistance, and can be widely applied to fields such as coatings, inks, and adhesives.

Description

Technical Field

[0001] The present invention relates to a silicone-based RAFT reagent for preparing acrylate anti-graffiti emulsion and a preparation method thereof, belonging to the field of fine chemical chemicals. Background Art

[0002] In recent years, with the progress of the preparation technology of anti-graffiti emulsion, silicone-modified acrylate anti-graffiti emulsion has been developed. The silicone-modified acrylate anti-graffiti emulsion not only has excellent film-forming properties, but also can improve the water resistance, stain resistance and scrub resistance of the coating film, thus attracting the attention of the industry.

[0003] At present, the silicone-modified acrylate anti-graffiti emulsion produced by the domestic conventional preparation method is mainly prepared by adding an organosilicon monomer containing an unsaturated bond and an acrylic monomer into a suitable auxiliary agent, and then through a core-shell coating polymerization process. This emulsion has characteristics such as high temperature resistance, water resistance and flexibility. However, due to the immature preparation technology, there are problems such as difficult polymerization of organosilicon monomers, easy self-crosslinking of silane active groups, use of high-cost reactive silicone oil, low introduction amount of organosilicon, and volatile organic compound pollution, which have a great impact on the product quality of the anti-graffiti emulsion. The conventional silicone-modified acrylate anti-graffiti emulsion is mainly prepared by emulsion polymerization method, but this preparation method has deficiencies such as low introduction rate of silicone oil, less surface migration of emulsifier and easy environmental pollution, so it has not been popularized and applied. The reversible addition-fragmentation chain transfer (RAFT) polymerization method has advantages such as lower reaction conditions, widely applicable monomers and controllable molecular weight of polymers. Therefore, when used to synthesize acrylate anti-graffiti emulsion, it can effectively improve the adhesion, weather resistance and chemical resistance of the emulsion.

[0004] Compared with the conventional preparation method, the method for preparing acrylate anti-graffiti emulsion with a silicone-based RAFT reagent is relatively simple, without the need to use organosilicon emulsifiers or co-solvents, and has characteristics such as environmental protection in production, low cost, easy operation and no volatile organic compounds. The anti-graffiti emulsion prepared by the present invention has characteristics such as ethanol resistance, stain resistance and washability, so it has good application prospects. Summary of the Invention

[0005] The purpose of the present invention is to provide a silicone-based RAFT reagent for preparing acrylate anti-graffiti emulsion and a preparation method thereof, aiming to solve many problems that usually occur in the preparation process of conventional silicone-modified acrylate anti-graffiti emulsion, such as difficult polymerization of organosilicon monomers, high cost of reactive silicone oil, low introduction amount of organosilicon, and volatile organic compound pollution, and to provide a more effective preparation method for preparing silicone-modified acrylate anti-graffiti emulsion with a silicone-based RAFT reagent.

[0006] The object of the present invention is achieved by the following technical solutions, which include the following steps:

[0007] Step (1): Add 9 - 20 parts of solvent, 2.5 - 3 parts of initiator, 3 - 18 parts of organosilicon - based RAFT reagent, 2.5 - 3 parts of methyl methacrylate, 1.5 - 2.2 parts of hydroxypropyl methacrylate, 1.5 - 2.2 parts of acrylic acid, and 3.4 - 4 parts of hydroxyethyl acrylate into a reaction kettle. Carry out a polymerization reaction at 60 - 90 °C and 200 - 600 rpm for 6 - 10 hours. Then, cool down to below 50 °C, neutralize with 1.8 - 2.2 parts of organic base, and remove low - boiling substances by vacuum distillation to obtain an organosilicon - containing acrylate polymer emulsifier.

[0008] Step (2): Dissolve 50 - 70 parts of deionized water in 14 - 32 parts of the organosilicon - containing acrylate pre - emulsion, and dropwise add 8 - 8.6 parts of methyl methacrylate, 5.5 - 6 parts of hydroxypropyl methacrylate, 12 - 14 parts of isobornyl methacrylate, 10 - 12 parts of hydroxyethyl acrylate, 2.5 - 3 parts of styrene, and 8 - 8.5 parts of butyl acrylate. At the same time, dropwise add 1.5 - 2.2 parts of initiator (dissolved in 20 - 34 parts of deionized water). Carry out a reversible addition - fragmentation chain - transfer radical polymerization reaction at 70 - 100 °C and 200 - 600 rpm for 3 - 6 hours. After dropping, keep the temperature for 40 - 80 minutes, and then cool down to room temperature to obtain an organosilicon - modified acrylate anti - graffiti emulsion.

[0009] Further, the structural formula of the organosilicon - based RAFT reagent is as follows:

[0010]

[0011] Wherein R1 represents any one of substituted or unsubstituted C1 - C3 alkyl groups, substituted or unsubstituted C1 - C3 alkenyl groups, or H bonds.

[0012] Further, the solvent described in step (1) is selected from one of isopropyl alcohol, ethyl acetate, or ethylene glycol dimethyl ether.

[0013] Further, the initiator of the polymer emulsifier described in step (1) is selected from azobisisobutyronitrile;

[0014] Further, the organic base described in step (1) is one of dimethylethanolamine, triethylamine, and ammonia water.

[0015] Further, the emulsion polymerization initiator described in step (2) is one of potassium persulfate, ammonium persulfate, or sodium persulfate.

[0016] Further, the structural formula of the organosilicon - modified acrylate anti - graffiti emulsion described in step (2) is as follows:

[0017] Among them, R1 represents any one of a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 alkenyl group, or an H bond.

[0018] The structural formula of M is as follows:

[0019]

[0020] Among them, R2, R4, and R5 are one of methyl or hydrogen, and R3 is various organic base substituents, hydrogen, methyl, ethyl, butyl, tert-butyl, hydroxyethyl, hydroxypropyl, glycidyl, isobornyl.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1) The silicone-modified acrylate anti-graffiti emulsion prepared with the silicone-based RAFT reagent of the present invention can effectively solve the problems in the preparation of conventional silicone-modified acrylate anti-graffiti emulsions, such as difficult polymerization of silicone monomers, high cost of reactive silicone oil, low silicone introduction amount, and volatile organic compound pollution.

[0023] 2) Compared with the conventional silicone-modified acrylate anti-graffiti emulsion, the silicone-modified acrylate anti-graffiti emulsion prepared with the silicone-based RAFT reagent of the present invention has a simple preparation method, a reasonable process, does not require a silicone emulsifier, does not generate volatile organic compounds, and is environmentally friendly in production and has low energy consumption.

[0024] 3) Compared with the conventional silicone-modified acrylate anti-graffiti emulsion, the silicone-modified acrylate anti-graffiti emulsion prepared with the silicone-based RAFT reagent of the present invention can effectively reduce the production cost of the anti-graffiti emulsion.

[0025] 4) Compared with the conventional silicone-modified acrylate anti-graffiti emulsion, the silicone-modified acrylate anti-graffiti emulsion prepared with the silicone-based RAFT reagent of the present invention has excellent water resistance, stain resistance, and ethanol resistance, and can avoid problems such as reduced film-forming performance of the emulsion and volatile organic compound pollution caused by using a silicone emulsifier or co-solvent.

[0026] 5) The method for preparing the silicone-modified acrylate anti-graffiti emulsion with the silicone-based RAFT reagent of the present invention is simple, does not require a silicone emulsifier, and has the characteristics of environmental protection in the production process, easy operation, and no volatile organic compounds.

[0027] 6) Compared with the conventional silicone-modified acrylate anti-graffiti emulsion prepared from the silicone-based RAFT reagent of the present invention, the silicone-modified acrylate anti-graffiti emulsion not only has extremely strong adhesion and good washability, but also has excellent heat resistance, weather resistance and chemical resistance, and can be widely used in the fields of coatings, inks, adhesives, etc. Detailed Embodiments

[0028] The embodiments of the present invention are described in detail below. The described embodiments are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0029] Using a silicone-based RAFT reagent, methyl methacrylate, hydroxypropyl methacrylate, acrylic acid, and hydroxyethyl acrylate as monomers, in the presence of an organic solvent and an initiator, a silicone-containing acrylate polymer emulsifier is prepared; using the silicone-containing acrylate polymer emulsifier as a raw material, dissolved in deionized water, methyl methacrylate, hydroxypropyl methacrylate, styrene, butyl acrylate, isobornyl methacrylate, and hydroxyethyl acrylate are added dropwise as monomers, and at the same time, a persulfate initiator (dissolved in deionized water) is added dropwise to obtain a silicone-modified acrylate anti-graffiti emulsion. The specific steps are as follows:

[0030] Step (1): Add 9-20 parts of solvent, 2.5-3 parts of initiator, 3-18 parts of silicone-based RAFT reagent, 2.5-3 parts of methyl methacrylate, 1.5-2.2 parts of hydroxypropyl methacrylate, 1.5-2.2 parts of acrylic acid, and 3.4-4 parts of hydroxyethyl acrylate to the reaction kettle, and carry out a polymerization reaction at 60-90 °C and 200-600 rpm for 6-10 hours. Then, cool down to below 50 °C, neutralize with 1.8-2.2 parts of organic base, and remove low-boiling substances by vacuum distillation to obtain a silicone-containing acrylate polymer emulsifier.

[0031] Step (2): Dissolve 14-32 parts of the silicone-containing acrylate polymer emulsifier in 50-70 parts of deionized water, add dropwise 8-8.6 parts of methyl methacrylate, 5.5-6 parts of hydroxypropyl methacrylate, 12-14 parts of isobornyl methacrylate, 10-12 parts of hydroxyethyl acrylate, 2.5-3 parts of styrene, and 8-8.5 parts of butyl acrylate. At the same time, add dropwise 1.5-2.2 parts of initiator (dissolved in 20-34 parts of deionized water), and carry out a reversible addition-fragmentation chain transfer radical polymerization reaction at 70-100 °C and 200-600 rpm for 3-6 hours. After dropping, keep warm for 40-80 minutes and cool down to room temperature to obtain a silicone-modified acrylate anti-graffiti emulsion.

[0032] The structural formula of the silicone-based RAFT reagent is as follows:

[0033]

[0034] Among them, R1 represents any one of a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 alkenyl group, or an H bond.

[0035] The solvent described in step (1) is selected from one of isopropyl alcohol, ethyl acetate, or ethylene glycol dimethyl ether.

[0036] The initiator of the pre-emulsion described in step (1) is selected from azobisisobutyronitrile;

[0037] The organic base described in step (1) is selected from one of dimethylethanolamine, triethylamine, and ammonia water.

[0038] The emulsion polymerization initiator described in step (2) is an aqueous solution of potassium persulfate, ammonium persulfate, or sodium persulfate.

[0039] The structural formula of the organosilicon-modified acrylate anti-graffiti emulsion is as follows:

[0040]

[0041] Among them, R1 represents any one of a substituted or unsubstituted C1-C3 alkyl group, a substituted or unsubstituted C1-C3 alkenyl group, or an H bond.

[0042] Among them, the structural formula of M is as follows:

[0043]

[0044] Among them, R2, R4, and R5 are one of methyl or hydrogen, and R3 is various of an organic base substituent, hydrogen, methyl, ethyl, butyl, tert-butyl, hydroxyethyl, hydroxypropyl, glycidyl, isobornyl.

[0045] In the above preparation method,

[0046] Preferably, in step (1), the stirring speed is 300 rpm, 400 rpm, or 500 rpm.

[0047] Preferably, in step (1), the reaction temperature is 60 °C, 70 °C, or 80 °C.

[0048] Preferably, in step (1), the reaction time is 6 hours, 7 hours, or 8 hours.

[0049] Preferably, in step (1), the organic base is selected from one of dimethylethanolamine, triethylamine, and ammonia water, and the amount of the organic base is 2 g, 2.5 g, or 3 g.

[0050] Preferably, in step (1), the solvent is selected from one of isopropyl alcohol, ethyl acetate, or ethylene glycol dimethyl ether.

[0051] Preferably, in step (1), the amount of the organosilicon-based RAFT reagent is 3 g, 7 g, or 11 g.

[0052] Preferably, in step (1), the initiator is azobisisobutyronitrile, and its amount is 0.15 g, 0.2 g, or 0.25 g.

[0053] Preferably, in step (1), the amount of methyl methacrylate in the emulsion is 2.5 g, 2.7 g, or 2.9 g.

[0054] Preferably, in step (1), the amount of hydroxypropyl methacrylate in the emulsion is 1.7 g, 1.9 g, or 2.1 g.

[0055] Preferably, in step (1), the amount of acrylic acid in the emulsion is 1.7 g, 1.9 g, or 2.1 g.

[0056] Preferably, in step (1), the amount of hydroxyethyl acrylate in the pre-emulsion is 3.5 g, 3.6 g, or 3.7 g.

[0057] Preferably, in step (2), the reaction temperature of the emulsion is 70 °C, 80 °C, or 90 °C.

[0058] Preferably, in step (2), the stirring speed is 300 rpm, 400 rpm, or 500 rpm.

[0059] Preferably, in step (2), the polymerization reaction time is 4 hours, 5 hours, or 6 hours.

[0060] Preferably, in step (2), the heat preservation time is 50 minutes, 60 minutes, or 70 minutes.

[0061] Preferably, in step (2), the initiator is one of potassium sulfate, ammonium persulfate, and sodium persulfate, and its amount is 0.3 g, 0.4 g, or 0.5 g.

[0062] Preferably, in step (2), the amount of deionized water for dissolving the high-molecular emulsifier is 40 g, 50 g, or 60 g.

[0063] Preferably, in step (2), the amount of deionized water for dissolving the initiator is 24 g, 28 g, or 32 g.

[0064] Preferably, in step (2), the amount of methyl methacrylate is 8 g, 9 g, or 10 g.

[0065] Preferably, in step (2), the amount of hydroxypropyl methacrylate is 5 g, 5.5 g, or 6 g.

[0066] Preferably, in step (2), the amount of isobornyl methacrylate is 12 g, 13 g, or 14 g.

[0067] Preferably, in step (2), the amount of 2-hydroxyethyl acrylate is 10 g, 11 g, or 12 g.

[0068] Preferably, in step (2), the amount of styrene is 2.5 g, 2.7 g, or 2.9 g.

[0069] Preferably, in step (2), the amount of butyl acrylate is 7 g, 8 g, or 9 g.

[0070] Hereinafter, multiple specific embodiments are listed by way of example.

[0071] Example 1

[0072] Add 3.75 g of organosilicon-based RAFT reagent, 2.6 g of methyl methacrylate, 1.9 g of hydroxypropyl methacrylate, 1.9 g of acrylic acid, 3.6 g of 2-hydroxyethyl acrylate, 0.2 g of azobisisobutyronitrile initiator, and 15 g of isopropanol solvent into a reaction kettle, react at 75 °C and 300 rpm for 10 hours, cool down to below 50 °C, neutralize with 2.5 g of dimethylethanolamine, and remove the low-boiling substances by vacuum distillation to obtain an organosilicon-containing acrylate polymer emulsifier. Dissolve 65 g of ionized water in the reaction kettle containing the organosilicon-containing acrylate polymer emulsifier, add dropwise 8.3 g of methyl methacrylate, 5.7 g of hydroxypropyl methacrylate, 13.07 g of isobornyl methacrylate, 11.05 g of 2-hydroxyethyl acrylate, 2.7 g of styrene, and 8.25 g of butyl acrylate, and simultaneously add dropwise 0.34 g of potassium persulfate initiator (dissolved in 28 g of deionized water), carry out a polymerization reaction at 82 °C and 400 rpm for 5 hours, keep warm for 60 minutes after dropping, and cool down to room temperature to obtain an organosilicon-modified acrylate anti-graffiti emulsion.

[0073] Example 2

[0074] 4.74 g of a silicone-based RAFT reagent, 2.7 g of methyl methacrylate, 1.89 g of hydroxypropyl methacrylate, 1.8 g of acrylic acid, 3.65 g of hydroxyethyl acrylate, 0.2 g of azobisisobutyronitrile initiator, and 16 g of isopropanol solvent were added to a reaction kettle. The reaction was carried out at 75 °C and 300 rpm for 10 hours. After cooling to below 50 °C, it was neutralized with 2.5 g of dimethylethanolamine, and the low-boiling substances were removed by vacuum distillation to obtain a silicone-containing acrylate polymer emulsifier. 64 g of ionized water was added to the reaction kettle containing the silicone-containing acrylate polymer emulsifier and dissolved. 8.5 g of methyl methacrylate, 5.7 g of hydroxypropyl methacrylate, 13.07 g of isobornyl methacrylate, 11.05 g of hydroxyethyl acrylate, 2.7 g of styrene, and 8.25 g of butyl acrylate were added dropwise. At the same time, 0.34 g of potassium persulfate initiator (dissolved in 28 g of deionized water) was added dropwise. The polymerization reaction was carried out at 82 °C and 400 rpm for 5 hours. After dropping, it was kept warm for 60 minutes and cooled to room temperature to obtain a silicone-modified acrylate anti-graffiti emulsion.

[0075] Example 3

[0076] 5.92 g of a silicone-based RAFT reagent, 2.8 g of methyl methacrylate, 1.88 g of hydroxypropyl methacrylate, 1.7 g of acrylic acid, 3.7 g of hydroxyethyl acrylate, 0.2 g of azobisisobutyronitrile initiator, and 16 g of butyl acetate solvent were added to a reaction kettle. The reaction was carried out at 75 °C and 300 rpm for 10 hours. After cooling to below 50 °C, it was neutralized with 2.8 g of dimethylethanolamine, and the low-boiling substances were removed by vacuum distillation to obtain a silicone-containing acrylate polymer emulsifier. 65 g of ionized water was added to the reaction kettle containing the silicone-containing acrylate polymer emulsifier and dissolved. 8.2 g of methyl methacrylate, 5.7 g of hydroxypropyl methacrylate, 13.05 g of isobornyl methacrylate, 11.05 g of hydroxyethyl acrylate, 2.7 g of styrene, and 8.25 g of butyl acrylate were added dropwise. At the same time, 0.34 g of potassium persulfate initiator (dissolved in 28 g of deionized water) was added dropwise. The polymerization reaction was carried out at 82 °C and 400 rpm for 5 hours. After dropping, it was kept warm for 60 minutes and cooled to room temperature to obtain a silicone-modified acrylate anti-graffiti emulsion.

[0077] Example 4

[0078] 8.88 g of a silicone-based RAFT reagent, 2.9 g of methyl methacrylate, 1.81 g of hydroxypropyl methacrylate, 1.75 g of acrylic acid, 3.8 g of hydroxyethyl acrylate, 0.2 g of azobisisobutyronitrile initiator, and 16 g of ethylene glycol dimethyl ether solvent were added to a reaction kettle. The reaction was carried out at 75 °C and 300 rpm for 10 hours. After cooling to below 50 °C, it was neutralized with 2.5 g of dimethylethanolamine, and the low-boiling substances were removed by vacuum distillation to obtain a silicone-containing acrylate polymer emulsifier. 65 g of ionized water was added to the reaction kettle containing the silicone-containing acrylate polymer emulsifier and dissolved. 8.1 g of methyl methacrylate, 5.7 g of hydroxypropyl methacrylate, 13.07 g of isobornyl methacrylate, 11.23 g of hydroxyethyl acrylate, 2.7 g of styrene, and 8.25 g of butyl acrylate were added dropwise. At the same time, 0.34 g of potassium persulfate initiator (dissolved in 28 g of deionized water) was added dropwise. The polymerization reaction was carried out at 82 °C and 400 rpm for 5 hours. After dropping, it was kept warm for 60 minutes and then cooled to room temperature to obtain a silicone-modified acrylate anti-graffiti emulsion.

[0079] The basic properties of the acrylate anti-graffiti emulsions prepared from the silicone-based RAFT reagent in Examples 1 to 4 are shown in Table 1.

[0080] Table 1 Basic properties of the acrylate anti-graffiti emulsions prepared from the silicone-based RAFT reagent

[0081]

[0082] It can be seen from the data in the table that the acrylate anti-graffiti emulsions prepared from the silicone-based RAFT reagent in Examples 1 to 4 have high heat resistance and excellent thermal stability, and thus can be widely used in fields such as coatings, inks, and adhesives.

[0083] The above are only the preferred embodiments of the present invention. It should be noted that: for those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of an acrylate anti-graffiti emulsion by using a silicone-based RAFT reagent, characterized in that, The method includes the following steps: Step (1): Add 9 - 20 parts of solvent, 2.5 - 3 parts of initiator, 3 - 18 parts of organosilicon - based RAFT reagent, 2.5 - 3 parts of methyl methacrylate, 1.5 - 2.2 parts of hydroxypropyl methacrylate, 1.5 - 2.2 parts of acrylic acid, 3.4 - 4 parts of hydroxyethyl acrylate into a reaction kettle, stir for 1 - 12 minutes at a temperature of 60 - 90 °C, then carry out RAFT polymerization for 6 - 10 hours. After the reaction ends, cool down to below 50 °C, then neutralize with 1.8 - 2.2 parts of organic base, and remove low - boilers by vacuum distillation to obtain an organosilicon - containing acrylate polymer emulsifier; Step (2): Add 14 - 32 parts of the organosilicon - containing acrylate polymer emulsifier described in step (1) into a reaction kettle, dissolve it with 50 - 70 parts of deionized water, then drop - wise add 8 - 8.6 parts of methyl methacrylate, 5.5 - 6 parts of hydroxypropyl methacrylate, 12 - 14 parts of isobornyl methacrylate, 10 - 12 parts of hydroxyethyl acrylate, 2.5 - 3 parts of styrene, 8 - 8.5 parts of butyl acrylate, 1.5 - 2.2 parts of initiator, stir for 1 - 12 minutes at a temperature of 70 - 100 °C, then carry out RAFT polymerization for 3 - 6 hours. After the reaction ends, keep the temperature for 40 - 80 minutes, and finally cool down to room temperature to obtain an organosilicon - modified acrylate anti - graffiti emulsion; The structural formula of the organosilicon - based RAFT reagent is as follows: Wherein R1 represents any one of substituted or unsubstituted C1 - C3 alkyl groups, substituted or unsubstituted C1 - C3 alkenyl groups or H bonds.

2. The preparation method of an organosilicon-based RAFT reagent for preparing an acrylate anti-graffiti emulsion according to claim 1, wherein: The organosilicon - based RAFT reagent described in step (1) is an organosilicon - based RAFT reagent made from RAFT reagent, diethoxydimethoxysilane and hexamethyldisiloxane.

3. The preparation method of an acrylate anti-graffiti emulsion prepared from a silicone-based RAFT reagent according to claim 1, characterized in that: The solvent described in step (1) is one of isopropanol, ethyl acetate or ethylene glycol dimethyl ether.

4. The preparation method of an acrylate anti-graffiti emulsion prepared from a silicone-based RAFT reagent according to claim 1, characterized in that: The initiator described in step (1) is azobisisobutyronitrile.

5. The preparation method of an acrylate anti-graffiti emulsion prepared from a silicone-based RAFT reagent according to claim 1, characterized in that: The organic base described in step (1) is one of dimethylethanolamine or triethylamine.

6. The preparation method of an acrylate anti-graffiti emulsion prepared from a silicone-based RAFT reagent according to claim 1, characterized in that: The initiator described in step (2) is one of potassium persulfate, ammonium persulfate or sodium persulfate.

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