Reactive flame retardant for transparent resin and flame-retardant acrylic resin

Abstract

The invention provides a reactive flame retardant for transparent resin and flame-retardant acrylic resin, the reactive flame retardant for transparent resin is THPO-AA or THPO-MAA, the molecular formula of the THPO-AA is as shown in the formula (1), and the molecular formula of the THPO-MAA is as shown in the formula (2). The flame retardant provided by the technical scheme of the invention has good compatibility with acrylic resin, and does not affect the transparency of the acrylic resin. In addition, THPO-AA contains hydroxyl, so that the adhesive force of THPO-AA to a base material can be improved. When the flame-retardant acrylic resin is used for LED packaging, the light extraction efficiency of an LED can be improved, chip heating is reduced, the service life is prolonged, meanwhile, the flame retardant property of the packaging resin is improved, the fire accident risk is reduced, and the flame-retardant acrylic resin has very important economic and social significance.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardants, and particularly to a reactive flame retardant for transparent resins and a flame-retardant acrylic resin. Background Art

[0002] Transparent resin products such as plexiglass are widely used in industrial and civil fields due to their excellent transparency and mechanical properties. However, due to their flammability, unmodified plexiglass cannot be used in fields with high fire and flame retardant safety requirements. Fields with high fire and flame retardant safety requirements include building window glass, construction, aviation, subway, vehicles, advertising and decoration, elevators, lighting fixtures and safety glass in industries such as electronic and electrical appliances.

[0003] Transparent flame-retardant plexiglass products often obtain flame retardancy by adding flame retardants. Due to concerns about the ecological environment, halogenated flame retardants have received close attention. At this time, the flame retardant industry is facing pressure to switch to flame retardants that are considered more environmentally friendly (such as organophosphorus flame retardants).

[0004] Many kinds of organophosphorus compounds are disclosed in the prior art that can impart flame retardancy to polymers. Most organophosphorus-based flame retardants belong to additive flame retardants, and additive phosphorus-based flame retardants have the disadvantages of poor compatibility with the resin matrix, easy exudation, large addition amount, and reduction of the mechanical properties of the resin matrix, which will lead to the deterioration of the physical and mechanical properties of the material. In particular, some organophosphorus flame retardants will cause the loss of transparency of plexiglass. Moreover, phosphorus is easily dissolved out after the product is discarded, which will cause pollution to the environment. Summary of the Invention

[0005] In view of the above technical problems, the present invention discloses a reactive flame retardant for transparent resins and a flame-retardant acrylic resin. While improving the flame retardant performance of the transparent resin, this flame retardant also has good compatibility with the acrylic resin and does not affect the transparency of the acrylic resin.

[0006] For this, the technical solution adopted by the present invention is as follows:

[0007] A reactive flame retardant for transparent resins, which is THPO-AA or THPO-MAA. The molecular formula of THPO-AA is shown in formula (1), and the molecular formula of THPO-MAA is shown in formula (2).

[0008]

[0009] The flame retardant adopting this technical solution is a reactive phosphorus-based flame retardant, containing double bonds, capable of copolymerizing with compounds containing double bonds, grafting the flame retardant onto the resin main chain, solving the migration problem of additive flame retardants, having less influence on the mechanical properties and other properties of the matrix resin, and having good compatibility with acrylic resins.

[0010] Moreover, THPO-AA and THPO-MAA have high phosphorus content and excellent flame retardant effect. Under the same conditions, the same flame retardant effect can be achieved with half less flame retardant than other flame retardants. By mixing monomers such as acrylate with THPO-AA and then adding an appropriate amount of conventional initiator, a flame retardant and highly transparent resin can be obtained.

[0011] THPO-AA and THPO-MAA contain large volume groups. The addition of these flame retardants can increase the glass transition temperature of the cured acrylic resin, thereby increasing the use temperature of the resin. Since THPO-AA and THPO-MAA contain more hydroxyl groups, the addition of these flame retardants can improve the adhesion of the cured acrylic resin, which is beneficial for the resin to bond metal and glass. This performance is especially important for LED packaging.

[0012] In addition, since THPO has three reactive groups, the flame retardant can have more reactive groups by adjusting the ratio. By adding the flame retardant to the acrylate monomer and curing it, a cross-linked product can be obtained. The stability, heat resistance and mechanical properties of the cured product will be improved.

[0013] The present invention also discloses a method for preparing the above-mentioned reactive flame retardant for transparent resin, wherein the reactive flame retardant for transparent resin is obtained by reacting trimethylolphosphine oxide with at least one of acrylic acid, methacrylic acid, acrylic anhydride, methacrylic anhydride, acryloyl chloride and methacryloyl chloride.

[0014] As a further improvement of the present invention, the reactive flame retardant for transparent resin is THPO-AA, and the preparation method of THPO-AA comprises:

[0015] Add THPO and AA in a molar ratio of 1:1 to 1:3 into a three-necked flask, add a catalyst, stir, and reflux at 60-95°C for 4-8 hours; after the reaction, wash with water, extract, separate the liquids to obtain a viscous transparent liquid, and vacuum dry to obtain THPO-AA;

[0016] Or add THPO and acryloyl chloride in a molar ratio of 1:1 to 1:3 into a three-necked flask, stir, add an acid absorber, and reflux at 40-70°C for 4-8 hours; after the reaction, wash and extract, separate the liquid to obtain a viscous transparent liquid, and vacuum dry to obtain THPO-AA;

[0017] Alternatively, THPO and acrylic anhydride are added into a three-necked flask in a molar ratio of 1:0.5 to 1:1.5, stirred, a catalyst is added, and the mixture is refluxed at a constant temperature of 60-95°C for 4-8 hours. After the reaction is completed, the mixture is washed with water, extracted, and separated to obtain a viscous transparent liquid, which is then vacuum dried to obtain THPO-AA.

[0018] As a further improvement of the present invention, the catalyst is at least one of sulfuric acid, phosphoric acid, benzenesulfonic acid, molecular sieve, zinc acetate, etc., and the acid absorbent is at least one of triethylamine, pyridine, potassium carbonate, potassium bicarbonate, sodium hydride, diisopropylethylamine, sodium carbonate, sodium bicarbonate, etc. Further, the molar amount of the catalyst used is about 1-5% (molar ratio) of the molar amount of THPO, and the molar amount of the acid absorbent used is 1.1 times the molar amount of acryloyl chloride used.

[0019] The present invention also discloses a flame-retardant acrylic resin, which is obtained by homopolymerization or copolymerization of the above-mentioned reactive flame retardant for transparent resin under the action of an initiator, or is obtained by polymerization of the above-mentioned reactive flame retardant for transparent resin with an ethylenic monomer or prepolymer under the action of an initiator.

[0020] As a further improvement of the present invention, the molecular formula of the flame-retardant acrylic resin is shown in formula (3):

[0021]

[0022] As a further improvement of the present invention, the initiator is a thermal initiator or a photoinitiator. Further, the initiator includes at least one of dibenzoyl peroxide, diisopropylbenzene peroxide, azobisisobutyronitrile, trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, and ethyl trimethylbenzoyl phenylphosphonate.

[0023] As a further improvement of the present invention, the vinyl monomer or prepolymer includes methyl methacrylate, ethyl acrylate, butyl acrylate, styrene, maleic anhydride, unsaturated polyester prepolymer, epoxy-modified acrylate prepolymer, polyurethane-modified acrylate prepolymer, silicone-modified acrylate prepolymer, trimethylolpropane diacrylate, pentaerythritol triacrylate, bis-trimethylolpropane triacrylate, 1,4-cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, polybutylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, 1,6-hexanediol acrylate monomer, ethoxylated-1,6-hexanediol diacrylate, hydroxypivalic acid neopentyl glycol ester diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated trimethylolpropane monomethyl ether diacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, propoxylated trimethylolpropane triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, bis-trimethylolpropane tetraacrylate, ethoxylated dipentaerythritol hexaacrylate, dipentaerythritol penta / hexaacrylate, or at least one of them.

[0024] As a further improvement of the present invention, the dosage of the initiator is 0.1-1 wt.% of the total amount of the vinyl monomer or prepolymer; the mass percentage content of the reactive flame retardant for the transparent resin in the flame-retardant acrylic resin is 20-60 wt.%.

[0025] The present invention also discloses a polymer-type flame retardant. Under the action of a thermal initiator and / or a photoinitiator, the reactive flame retardant for the transparent resin as described above undergoes a homopolymerization or copolymerization reaction. The homopolymerization yields the polymer-type flame retardant PTHPO-AA or PTHPO-MAA, the copolymerization yields the polymer-type flame retardant PTHPO-AA-THPO-MAA, or PTHPO-AA and PTHPO-MAA can also be blended to obtain a blended polymer-type flame retardant;

[0026] The molecular formula of the PTHPO-AA is as shown in Formula (4), and the molecular formula of the PTHPO-MAA is as shown in Formula (5):

[0027]

[0028]

[0029] As a further improvement of the present invention, the aggregated PTHPO-AA or PTHPO-MAA solid is granulated or pulverized.

[0030] The present invention also discloses a flame retardant material, which is obtained by kneading the above-mentioned polymer type flame retardant with a polymer material, wherein the dosage of the polymer type flame retardant is 20 wt.% - 40 wt.%. Further, the polymer material is one of nylon, PMMA, polycarbonate, ABS, etc.

[0031] The present invention discloses the application of the above-mentioned flame retardant acrylic resin in LED packaging.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] The flame retardant of the technical solution of the present invention has good compatibility with the acrylic resin and does not affect the transparency of the acrylic resin. Moreover, THPO-AA contains hydroxyl groups, which can improve the adhesion of THPO-AA to the substrate. When the flame retardant acrylic resin of the present invention is used for LED packaging, it can improve the flame retardant performance of the packaging resin and reduce the risk of fire accidents, which has very important economic and social significance. Specific Embodiments

[0034] The following further details the preferred embodiments of the present invention.

[0035] A reactive acrylate phosphorus-containing flame retardant is synthesized by trimethylolphosphine oxide (THPO) and acrylic acid (AA), methacrylic acid (MAA), acrylic anhydride, methacrylic anhydride, acryloyl chloride or methacryloyl chloride through esterification or other methods.

[0036] The typical molecular formula is as follows:

[0037]

[0038] The typical esterification process for the preparation of THPO-AA includes:

[0039] Add THPO and AA to a three-necked flask in a molar ratio of 1:1 - 1:3, add an appropriate amount of catalyst, stir, and carry out a reflux reaction in a constant temperature water bath at 60 - 95 °C for 4 - 8 hours. After the experiment, wash with water for extraction, separate the liquid, obtain a viscous transparent liquid, and then dry it under vacuum to obtain THPO-AA. The reaction formula is as follows:

[0040]

[0041] Alternatively, THPO and acryloyl chloride are added to a three-necked flask in a molar ratio of 1:1 to 1:3, stirred, an appropriate acid absorbent is added, and the mixture is kept in a constant temperature water bath at 40 - 70 °C for reflux reaction for 4 - 8 hours. After the experiment, it is washed with water, extracted, separated to obtain a viscous transparent liquid, and then dried under vacuum to obtain THPO-AA. The reaction formula is as follows:

[0042]

[0043] Alternatively, THPO and acrylic anhydride are added to a three-necked flask in a molar ratio of 1:0.5 to 1:1.5, stirred, an appropriate catalyst is added, and the mixture is kept in a constant temperature water bath at 60 - 95 °C for reflux reaction for 4 - 8 hours. After the experiment, it is washed with water, extracted, separated to obtain a viscous transparent liquid, and then dried under vacuum to obtain THPO-AA. The reaction formula is as follows:

[0044]

[0045] Alternatively, THPO-AA is mixed with an initiator and an olefin monomer or prepolymer in a certain proportion, stirred evenly, and then cured. The aforementioned initiator is a photoinitiator or a thermal initiator, including any reagent known to those skilled in the art, and the initiator can be a mixture of one or more. Examples include but are not limited to: benzoyl peroxide (BPO), dicumyl peroxide (DCP), azobisisobutyronitrile, trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, ethyl trimethylbenzoyl phenylphosphinate or a mixture thereof.

[0046] Typical reaction formulas are as follows:

[0047]

[0048] The ethylenic monomers or prepolymers as described above include any ethylenic monomers or prepolymers known to those skilled in the art, including but not limited to methyl methacrylate (MMA), ethyl acrylate, butyl acrylate, styrene, maleic anhydride, unsaturated polyester prepolymers, epoxy-modified acrylate prepolymers, polyurethane-modified acrylate prepolymers, silicone-modified acrylate prepolymers, trimethylolpropane diacrylate, pentaerythritol triacrylate, bis-trimethylolpropane triacrylate, 1,4-cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, polybutylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, 1,6-hexanediol acrylate monomer, ethoxylated-1,6-hexanediol diacrylate, hydroxypivalic acid neopentyl glycol ester diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated trimethylolpropane monomethyl ether diacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, propoxylated trimethylolpropane triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, bis-trimethylolpropane tetraacrylate, ethoxylated dipentaerythritol hexaacrylate, dipentaerythritol penta / hexaacrylate, and at least one of them.

[0049] The prepared flame retardant can be directly used in the flame retardant acrylic resin to achieve the flame retardant effect. It is also possible to add THPO-AA and / or THPO-MAA or other ethylenic monomers, and under the action of a thermal initiator or a photoinitiator or both initiators, through homopolymerization or copolymerization, a flame retardant acrylic resin is formed by a polymerization reaction. The polymerization conditions are thermal initiation or photoinitiation, or a combination of the two initiation methods. A typical molecular formula of the flame retardant acrylic resin is as shown in Formula (3):

[0050]

[0051] As described above, the curing method of the flame retardant acrylic resin uses thermal curing or photo curing or both curing methods simultaneously depending on the type of initiator. The dosage of the initiator is 0.1 to 1% of the total amount of the monomer or prepolymer. The content of THPO-AA in the cured ethylenic resin is 20% to 60%.

[0052] A polymer flame retardant is obtained by homopolymerization or copolymerization of the above-mentioned transparent resin with a reactive flame retardant under the action of a thermal initiator and / or a photoinitiator. The homopolymerization yields the polymer flame retardant PTHPO-AA or PTHPO-MAA, and the copolymerization yields the polymer flame retardant PTHPO-AA-THPO-MAA. Alternatively, PTHPO-AA and PTHPO-MAA can be blended to obtain a blended polymer flame retardant.

[0053] The molecular formula of the said PTHPO-AA is shown in Formula (4), and the molecular formula of the said PTHPO-MAA is shown in Formula (5):

[0054]

[0055] A flame retardant material is obtained by kneading the above-mentioned polymer flame retardant with a polymer material. Among them, the dosage of the polymer flame retardant is 20wt.%-40wt.%. Further, the polymer material is one of nylon, PMMA, polycarbonate, ABS, etc.

[0056] Specifically, the preparation method of THPO-AA includes the following steps:

[0057] Add THPO and AA into a three-necked flask at a molar ratio of 1:1, stir, add an appropriate amount of concentrated sulfuric acid (1% (molar ratio) of the amount of THPO), keep the temperature in a constant water bath at 60°C, and reflux for 6 hours. After the experiment, wash with water for extraction, separate the liquid, obtain a viscous transparent liquid, and then dry it under vacuum to obtain THPO-AA.

[0058] Or it includes the following steps:

[0059] Add THPO and AA into a three-necked flask at a molar ratio of 1:3, stir, add an appropriate amount of concentrated sulfuric acid (5% (molar ratio) of the amount of THPO), keep the temperature in a constant water bath at 95°C, and reflux for 5 hours. After the experiment, wash with water for extraction, separate the liquid, obtain a viscous transparent liquid, and then dry it under vacuum to obtain THPO-AA.

[0060] Or it includes the following steps:

[0061] Add THPO and acryloyl chloride into a three-necked flask at a molar ratio of 1:1, stir, add an appropriate amount of sodium bicarbonate powder (1.1 times (molar ratio) of the amount of acryloyl chloride), keep the temperature in a constant water bath at 45°C, and reflux for 5 hours. After the experiment, wash with water for extraction, separate the liquid, obtain a viscous transparent liquid, and then dry it under vacuum to obtain THPO-AA.

[0062] Or it includes the following steps:

[0063] THPO and acrylic anhydride were added to a three-necked flask at a molar ratio of 1:0.5, stirred, and an appropriate amount of concentrated phosphoric acid (1% (molar ratio) of the amount of THPO) was added. The mixture was kept in a constant temperature water bath at 60 °C and refluxed for 5 hours. After the experiment, it was washed with water, extracted, and separated to obtain a viscous transparent liquid, which was then dried under vacuum to obtain THPO-AA.

[0064] The prepared THPO-AA was mixed with a photoinitiator or a thermal initiator in a certain proportion, stirred evenly, and defoamed on an ultrasonic machine to form a mixture. Then, photoinitiated polymerization was carried out to obtain a solid PTHPO-AA. The solid was granulated or pulverized to obtain the high phosphorus-containing polymeric flame retardant PTHPO-AA.

[0065] To further illustrate that THPO-AA has a relatively high light transmittance and flame retardancy for vinyl resin compositions, specific examples will be listed below for further description.

[0066] Examples 1 to 9

[0067] THPO-AA, a vinyl monomer or prepolymer, and a photoinitiator or thermal initiator were mixed in a certain proportion, stirred evenly, and defoamed on an ultrasonic machine to form a mixture. Then, the mixture samples were respectively poured into a silicone rubber mold for curing; the cured samples were respectively tested. Specifically

[0068] In Examples 1 to 3, flame-retardant acrylic resins were obtained by reacting THPO-AA with MMA and an initiator. The mass percentages of THPO-AA, MMA, and the initiator are shown in Table 1 respectively. In Comparative Examples 1 to 3, resins were obtained by reacting a phosphate ester (RDP) flame retardant with MAA. The mass percentages of the specific reactants are shown in Table 1.

[0069] In Examples 4 to 5, flame-retardant acrylic resins were obtained by reacting THPO-AA with a polyurethane-modified acrylate prepolymer. The mass percentages of the specific reactants are shown in Table 1.

[0070] In Examples 6 to 7, flame-retardant acrylic resins were obtained by reacting THPO-AA with an unsaturated polyester prepolymer. The mass percentages of the specific reactants are shown in Table 1.

[0071] The obtained resins were tested for flame retardancy, migration resistance, extraction resistance, water absorption, and adhesion. The performance test results are shown in Table 1.

[0072] Table 1 Comparison of formulations and properties of Examples 1 to 8 and Comparative Examples 1 to 3

[0073]

[0074] Note: The percentages in Table 1 are mass percentages.

[0075] From the data comparison in Table 1, it can be seen that the flame retardant adopting the technical solution of the embodiment of the present invention has good compatibility with the acrylic resin and can improve the flame retardant performance of the transparent resin.

[0076] Examples 8 - 14

[0077] Under the action of a thermal initiator or a photoinitiator or both initiators, THPO-AA and / or THPO-MAA are subjected to homopolymerization or copolymerization to generate a high phosphorus-containing polymeric flame retardant through a polymerization reaction. The polymerization conditions are thermal initiation or photoinitiation, or a combination of the two initiation methods, and PTHPO-AA or PTHPO-MAA is obtained by homopolymerization. Further, the obtained solid PTHPO-AA or PTHPO-MAA is granulated or pulverized for later use.

[0078] Example 8

[0079] Under the action of 0.1% thermal initiator, THPO-AA is thermally initiated at 60°C for 24 h to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA is granulated or pulverized for later use.

[0080] PTHPO-AA and polymethyl methacrylate (PMMA) are mixed in different proportions, stirred evenly, and kneaded evenly by a twin-screw extruder or a kneader, etc., to obtain the corresponding flame retardant materials.

[0081] Example 9

[0082] Under the action of 0.1% thermal initiator, THPO-AA is thermally initiated at 55°C for 48 h to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA is granulated or pulverized for later use.

[0083] PTHPO-AA and polymethyl methacrylate (PMMA) are mixed in different proportions, stirred evenly, and kneaded evenly by a twin-screw extruder or a kneader, etc., to obtain the corresponding flame retardant materials.

[0084] Example 10

[0085] Under the action of 0.5% photoinitiator, THPO-AA is photoinitiated and reacted in a light curing machine for 20 min to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA is granulated or pulverized for later use.

[0086] PTHPO-AA and polymethyl methacrylate (PMMA) are mixed in different proportions, stirred evenly, and kneaded evenly by a twin-screw extruder or a kneader, etc., to obtain the corresponding flame retardant materials.

[0087] Example 11

[0088] Under the action of 1% photoinitiator, THPO-AA was subjected to photoinitiation and reacted in a light curing machine for 10 min to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA was granulated or pulverized for later use.

[0089] PTHPO-AA (30%) and nylon (70%) were mixed in proportion, stirred evenly, and kneaded evenly by a twin-screw extruder or an internal mixer, etc., to obtain the corresponding flame retardant material.

[0090] Example 12

[0091] Under the action of 1% photoinitiator, THPO-AA was subjected to photoinitiation and reacted in a light curing machine for 10 min to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA was granulated or pulverized for later use.

[0092] PTHPO-AA (40%) and nylon (60%) were mixed in proportion, stirred evenly, and kneaded evenly by a twin-screw extruder or an internal mixer, etc., to obtain the corresponding flame retardant material.

[0093] Example 13

[0094] Under the action of 0.1% thermal initiator and 0.5% photoinitiator, THPO-AA was first subjected to photoinitiation and reacted in a light curing machine for 10 min, and then subjected to thermal initiation at 95 °C for 1 h to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA was granulated or pulverized for later use.

[0095] PTHPO-AA (30%) and polycarbonate (70%) were mixed in proportion, stirred evenly, and kneaded evenly by a twin-screw extruder or an internal mixer, etc., to obtain the corresponding flame retardant material.

[0096] Example 14

[0097] Under the action of 0.1% thermal initiator and 1% photoinitiator, THPO-AA was first subjected to photoinitiation and reacted in a light curing machine for 5 min, and then subjected to thermal initiation at 95 °C for 1 h to obtain PTHPO-AA by homopolymerization. The obtained solid PTHPO-AA was granulated or pulverized for later use.

[0098] PTHPO-AA (40%) and polycarbonate (60%) were mixed in proportion, stirred evenly, and kneaded evenly by a twin-screw extruder or an internal mixer, etc., to obtain the corresponding flame retardant material.

[0099] For each of Examples 8 - 14, the raw materials and mass percentages used in the formulation are shown in Table 2. Flame retardant resins obtained by mixing PMMA and phosphate ester (RDP) flame retardants in different proportions are used as Comparative Examples 4 - 6.

[0100] Examples 11 - 12 are resins obtained by mixing PTHPO - AA and nylon in different proportions, and Examples 13 - 14 are resins obtained by mixing PTHPO - AA and polycarbonate in different proportions. The performance test results of the above resins are shown in Table 2 for details.

[0101] Table 2 Comparison of formulations and properties between Examples 8 - 14 and Comparative Examples 4 - 6

[0102]

[0103] Note: The % in Table 2 for the dosage is the mass percentage.

[0104] From the data comparison in Table 2, it can be seen that the flame retardants using the technical solutions of the examples of the present invention have good durability, resistance to migration, resistance to extraction, and excellent flame retardancy when combined with PMMA, nylon, and polycarbonate.

[0105] Comparative Example 7

[0106] THPO and AA were added to a three - necked flask in a molar ratio of 2:1, stirred, an appropriate amount of concentrated sulfuric acid was added, and the mixture was kept in a constant temperature water bath at 60°C and refluxed for 6 hours. After the experiment, it was washed with water for extraction, separated, and a viscous transparent liquid was obtained, and then dried under vacuum to obtain THPO - AA. Since the excess part of THPO did not participate in the reaction and THPO is soluble in water, during the water - washing extraction, the excess part of THPO dissolved in water and was lost, resulting in an aggravation of the sewage treatment problem and also a decrease in the yield of THPO - AA.

[0107] Comparative Example 8

[0108] THPO and AA were added to a three - necked flask in a molar ratio of 1:4, stirred, an appropriate amount of concentrated sulfuric acid was added, and the mixture was kept in a constant temperature water bath at 60°C and refluxed for 6 hours. After the experiment, it was washed with water for extraction, separated, and a viscous transparent liquid was obtained, and then dried under vacuum to obtain THPO - AA. Since the excess part of AA did not participate in the reaction and AA is soluble in water, during the water - washing extraction, the excess part of AA dissolved in water and was lost, resulting in an aggravation of the sewage treatment problem and also a decrease in the yield of THPO - AA.

[0109] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A reactive flame retardant for transparent resin, characterized in that: It is THPO-AA or THPO-MAA, the molecular formula of THPO-AA is shown in formula (1), the molecular formula of THPO-MAA is shown in formula (2), 2. The method for preparing a reactive flame retardant for transparent resin according to claim 1, characterized in that: The reactive flame retardant for transparent resin is obtained by reacting trimethylolphosphine oxide with at least one of acrylic acid, methacrylic acid, acrylic anhydride, methacrylic anhydride, acryloyl chloride and methacryloyl chloride.

3. The method for preparing a reactive flame retardant for transparent resin according to claim 2, characterized in that: The reactive flame retardant for transparent resin is THPO-AA, and the preparation method of THPO-AA comprises: Add THPO and AA in a molar ratio of 1:1 to 1:3 into a three-necked flask, add a catalyst, stir, and reflux at 60-95°C for 4-8 hours; after the reaction, wash with water, extract, separate the liquids to obtain a viscous transparent liquid, and vacuum dry to obtain THPO-AA; Or add THPO and acryloyl chloride in a molar ratio of 1:1 to 1:3 into a three-necked flask, stir, add an acid absorber, and reflux at 40-70°C for 4-8 hours; after the reaction, wash and extract, separate the liquid to obtain a viscous transparent liquid, and vacuum dry to obtain THPO-AA; Alternatively, THPO and acrylic anhydride are added into a three-necked flask in a molar ratio of 1:0.5 to 1:1.5, stirred, a catalyst is added, and the mixture is refluxed at a constant temperature of 60-95°C for 4-8 hours. After the reaction is completed, the mixture is washed with water, extracted, and separated to obtain a viscous transparent liquid, which is then vacuum dried to obtain THPO-AA.

4. The method for preparing a reactive flame retardant for transparent resin according to claim 3, characterized in that: The catalyst is at least one of sulfuric acid, phosphoric acid, benzenesulfonic acid, molecular sieve, and zinc acetate; the acid absorber is at least one of triethylamine, pyridine, potassium carbonate, potassium bicarbonate, sodium hydride, diisopropylethylamine, sodium carbonate, and sodium bicarbonate; the amount of the catalyst is 1 to 5% of the amount of THPO, and the amount of the acid absorber is 1.1 times the amount of acryloyl chloride.

5. Flame retardant acrylic resin, characterized in that: The transparent resin is obtained by homopolymerizing or copolymerizing the reactive flame retardant for transparent resin as claimed in claim 1 under the action of an initiator, or by polymerizing the reactive flame retardant for transparent resin as claimed in claim 1 with an olefin monomer or prepolymer under the action of an initiator.

6. The flame retardant acrylic resin according to claim 5, characterized in that: The molecular formula of the flame retardant acrylic resin is shown in formula (3):

7. The flame retardant acrylic resin according to claim 5, characterized in that: The initiator is a thermal initiator or a photoinitiator, and the initiator includes at least one of dibenzoyl peroxide, dicumyl peroxide, azobisisobutyronitrile, trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenylacetone, and trimethylbenzoylphenylphosphonic acid ethyl ester.

8. The flame retardant acrylic resin according to claim 7, characterized in that: The vinyl monomer or prepolymer includes methyl methacrylate, ethyl acrylate, butyl acrylate, styrene, maleic anhydride, unsaturated polyester prepolymer, epoxy-modified acrylate prepolymer, polyurethane-modified acrylate prepolymer, silicone-modified acrylate prepolymer, trimethylolpropane diacrylate, pentaerythritol triacrylate, ditrimethylolpropane triacrylate, 1,4-cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, polybutylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, At least one of alcohol diacrylate, 1,6-hexanediol acrylate monomer, ethoxylated-1,6-hexanediol diacrylate, hydroxypivalate neopentyl glycol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated trimethylolpropane methyl ether diacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated glycerol triacrylate, propoxylated trimethylolpropane triacrylate, tri(2-hydroxyethyl)isocyanuric acid triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, ethoxylated dipentaerythritol hexaacrylate, and dipentaerythritol penta / hexaacrylate; The amount of the initiator is 0.1-1 wt.% of the total amount of the vinyl monomer or prepolymer; the mass percentage content of the reactive flame retardant for transparent resin in the flame retardant acrylic resin is 20-60 wt.%.

9. A polymer flame retardant, characterized in that: The reactive flame retardant for transparent resin as claimed in claim 1 is subjected to homopolymerization or copolymerization reaction under the action of a thermal initiator and / or a photoinitiator to obtain a polymer flame retardant PTHPO-AA or PTHPO-MAA through homopolymerization, a polymer flame retardant PTHPO-AA-THPO-MAA through copolymerization, or PTHPO-AA and PTHPO-MAA are blended to obtain a blended polymer flame retardant; The molecular formula of the PTHPO-AA is shown in formula (4), and the molecular formula of the PTHPO-MAA is shown in formula (5):

10. A flame retardant material, characterized in that: It is obtained by mixing the polymer flame retardant as claimed in claim 9 with a polymer material, wherein the amount of the polymer flame retardant is 20wt.%-40wt.%.

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