Halogen-free flame-retardant modified epoxy acrylate resin and preparation method thereof

Abstract

The present application relates to the technical fields of polymer and resin, especially to IPC C08G59, and more particularly to a halogen-free flame-retardant modified epoxy acrylic resin and a preparation method thereof.The present application provides a halogen-free flame-retardant modified epoxy acrylic resin, liquid phosphoric acid is reacted with a tetrafunctional glycidyl amine special epoxy resin, phosphorus elements are grafted onto the main chain of the epoxy resin, the reaction time is reduced, and the flame-retardant properties of the epoxy resin are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer and resin, especially to IPC C08G59, and more particularly to a halogen-free flame-retardant modified epoxy acrylic resin and a preparation method thereof. BACKGROUND

[0002] As a monomer or oligomer material of thermosetting polymer, epoxy resin can react with various types of curing agents to form materials with high mechanical properties, bonding properties, electrical insulation and chemical resistance, which plays an important role in material bonding, functional coatings, electrical insulation and carbon fiber composites. However, its flammable property brings great safety hazards to the use of materials.

[0003] The existing patent CN201810870544.1 discloses a kind of epoxy acrylic resin flame-retardant coating and preparation method thereof, comprising the following raw materials: epoxy acrylic ester prepolymer 20-40, flame retardant 15-40, initiator 0.5-1.5, pigment 4-10, dispersing agent 1.5-3.5, inorganic filler 4-10, defoaming agent 2-5, film forming aid 2-6, solvent 5-30. The application improves the flame-retardant property by adding a reactive flame retardant, but the flame retardant is a halogen flame retardant, which generates a large amount of smoke and toxic and corrosive gas during combustion, which is harmful, and its flame-retardant property needs to be improved. In addition, the flame retardant may appear precipitation phenomenon, thereby reducing the flame-retardant effect.

[0004] Therefore, it is necessary to develop a low-smoke, non-toxic halogen-free flame-retardant modified epoxy acrylic resin. SUMMARY

[0005] In order to solve the problems in the prior art, the present application provides a preparation method of a halogen-free flame-retardant modified epoxy acrylic resin, comprising the following steps:

[0006] S1: dissolve the epoxy resin in 50-150 mL of organic solvent, add the flame retardant and the polymerization inhibitor, stir, heat and reflux, then rotary evaporate to remove the organic solvent in the reaction product, freeze-dry to remove the water in the reaction product, and obtain a light yellow transparent solid;

[0007] S2: grind the light yellow transparent solid with a marl mortar, wash the unreacted reagents in the ground light yellow transparent solid with an organic solvent, and obtain a light yellow powder after rotary evaporation and drying, which is named as phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin.

[0008] Preferably, the organic solvent comprises one or more of acetone, methyl ethyl ketone, cyclohexanone and ethyl acetate.

[0009] Preferably, the epoxy resin comprises a tetrafunctional glycidyl amine special epoxy resin.

[0010] Preferably, the tetrafunctional glycidyl amine special epoxy resin is epoxidized m-xylene diamine.

[0011] Preferably, the epoxidized m-xylene diamine is purchased from Wuhan Chengtian Fine Chemical Co., Ltd., with the product number AG-601.

[0012] Preferably, the CAS number of the epoxidized m-xylene diamine is 63738-22-7.

[0013] In the present application, a specific epoxidized m-xylene diamine is selected, which reduces the reaction time in the reaction process. The present inventors have unexpectedly found that the tertiary amine structure in the structure of the epoxidized m-xylene diamine has a certain self-catalytic effect on the reaction process, which reduces the reaction time in the reaction process.

[0014] Preferably, the flame retardant comprises phosphoric acid.

[0015] Preferably, the phosphoric acid is an 85wt% orthophosphoric acid aqueous solution.

[0016] Preferably, the polymerization inhibitor comprises one or more of hydroquinone, o-methyl hydroquinone, p-hydroxyanisole, p-benzoquinone and 2,6-di-tert-butyl-4-methylphenol.

[0017] Preferably, the polymerization inhibitor accounts for 0.1% of the total mass of the epoxy resin and the phosphoric acid.

[0018] Preferably, the molar ratio of the epoxy resin to the phosphoric acid is (1.5-2.5):1.

[0019] Preferably, the temperature of the heating reflux is 50-70℃.

[0020] In the present application, by selecting a specific tetrafunctional glycidyl amine special epoxy resin and reacting with phosphoric acid, a new type of halogen-free flame-retardant modified epoxy acrylate resin can be obtained. The flame-retardant performance of the current epoxy resin is poor, and the present inventors have creatively combined a specific tetrafunctional glycidyl amine special epoxy resin and the flame retardant phosphoric acid, thereby improving the flame-retardant performance of the epoxy acrylate. The present inventors have unexpectedly found that the specific tetrafunctional glycidyl amine special epoxy resin (epoxidized m-xylene diamine) contains four epoxy groups, and its activity is higher than that of ordinary epoxy resin. The epoxy groups in the molecule can react with the active hydrogen in the phosphoric acid, thereby grafting phosphorus elements onto the main chain of the epoxy resin, thereby improving the flame-retardant properties of the epoxy resin.

[0021] The second aspect of the present application provides a preparation method of a halogen-free flame-retardant modified epoxy acrylate resin.

[0022] The reaction equation of the halogen-free flame-retardant modified epoxy acrylic resin is:

[0023]

[0024] Advantages

[0025] 1. In the present application, a novel halogen-free flame-retardant modified epoxy acrylic resin can be obtained by selecting a specific tetrafunctional glycidyl amine special epoxy resin to react with phosphoric acid.

[0026] 2. In the present application, a specific epoxidized m-xylylenediamine is selected, thereby reducing the reaction time in the reaction process.

[0027] 3. In the present application, by controlling the temperature of heating reflux to be 50-70℃, the reaction time is reduced, and the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin can be successfully obtained.

[0028] 4. In the present application, the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin contains not only P-N flame-retardant elements, but also a large amount of hydroxyl groups, so that the resin has good water solubility and can become a flame-retardant resin matrix of water-based paint.

[0029] 5. In the present application, liquid phosphoric acid reacts with the amphetyl tetrafunctional epoxy resin AG-601, and the phosphorus element is grafted onto the main chain of the epoxy resin, which can effectively solve the problem of precipitation of small molecule flame retardants. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is the infrared spectrum of AG-601 and phosphoric acid in Example 1;

[0031] Figure 2 It is the thermal gravimetric test curve of the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin in Example 1 and the epoxy acrylic resin in Comparative Example 1 in air;

[0032] Figure 3 It is the result of the combustion experiment of the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin in Example 1; from top to bottom, the first row is the combustion of AG-601 in Comparative Example 1 from 1s to 120s; the middle row is the first combustion of the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin prepared in Example 1 from 1s to 100s; the lowermost is the second combustion of the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylic resin prepared in Example 1 from 1s to 48s. DETAILED DESCRIPTION

[0033] Example 1

[0034] The first aspect of the embodiment provides a preparation method of halogen-free flame-retardant modified epoxy-acrylic resin, comprising the following steps:

[0035] S1: Dissolve epoxidized m-xylylenediamine (0.6 mol) in 100 mL of acetone, then add 85wt% aqueous phosphoric acid (0.3 mol), p-hydroxyanisole (0.1% of the total mass of epoxidized m-xylylenediamine and 85wt% aqueous phosphoric acid), stir, heat to 60°C under reflux, keep for 3h, then rotary evaporate to remove acetone in the reactants, freeze-dry to remove moisture in the reactants, and obtain a light yellow transparent solid.

[0036] S2: Grind the light yellow transparent solid with a marl mortar, wash the ground light yellow transparent solid with an organic solvent to remove unreacted reagents, and after rotary evaporation and drying, obtain a light yellow powder, which is named as phosphorus-nitrogen halogen-free flame-retardant modified epoxy-acrylic resin.

[0037] The epoxidized m-xylylenediamine is purchased from Wuhan Chengtian Fine Chemical Co., Ltd., with the product number AG-601.

[0038] The CAS number of the epoxidized m-xylylenediamine is 63738-22-7.

[0039] The CAS number of the p-hydroxyanisole is 150-76-5.

[0040] The 85wt% aqueous phosphoric acid is purchased from Jinan Mengqiao Chemical Co., Ltd.

[0041] Comparative Example 1

[0042] Comparative Example 1 provides an epoxy-acrylic resin, which is AG-601.

[0043] Comparative Example 2

[0044] The specific implementation of Comparative Example 2 is the same as that of Example 1, except that the heating under reflux is to 75°C.

[0045] After half an hour of reaction, the gelation phenomenon is obtained: the viscosity of the reactants becomes large, the climbing rod phenomenon occurs, and the reactants become gelatinous solid.

[0046] Performance test

[0047] 1. Determine the infrared spectra of AG-601 and phosphoric acid by an infrared spectrometer; the results are shown in Figure 1 : It can be seen from Figure 1 that the infrared absorption peaks of AG-601 and phosphoric acid are at 1212cm -1 and 1055cm -1The characteristic absorption peak of P-O-C bond appears at the same position as that of aromatic P-O-C bond, indicating that ring-opening reaction occurs between phosphoric acid and epoxy group of AG-601, thus producing phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylate resin with hydroxyl group.

[0048] 2. The phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylate resin obtained in Example 1 and the epoxy acrylate resin in Comparative Example 1 were analyzed by thermogravimetric analyzer at 0-700°C, and the corresponding DTG was calculated through TG value. The results are shown in Table 1. Figure 2 : From Figure 2 It can be seen that the phosphorus-nitrogen halogen-free flame-retardant modified epoxy acrylate resin starts to degrade at 286°C, the maximum mass loss rate appears at about 537°C, and the mass fraction of solid residue at 700°C is about 35.1wt%. The epoxy acrylate resin in Comparative Example 1 starts to degrade at 268°C, the maximum mass loss rate appears at about 435°C, and the mass fraction of solid residue at 700°C is about 9.5wt%.

[0049] The temperature at which the mass loss rate is 5wt% in Figure 2 is T -5％ , the midpoint temperature of degradation is T -50％ , and the residual amount of solid at 700°C is recorded in Table 1.

[0050] Table 1

[0051] T -5％ (°C) T -50％ (°C) Char residue (%) at 700°C Example 1 286 537 35.1 Comparative Example 1 268 435 9.5

[0052] 3. UL-94 vertical burning test

[0053] The standard sample in Example 1 and Comparative Example 1 was vertically fixed on the sample clamp, and the bottom was 300mm away from the horizontally laid medical absorbent cotton. The ignition was made at 10mm from the lower end surface of the sample, and the off-fire self-extinguishing time of the material after two ignitions was recorded respectively. According to the off-fire self-extinguishing time and its total, and whether there are drippings or not, the flammability of the material was divided into three grades of V-0, V-1 and V-2. The process diagram is shown in Figure 3 .

[0054] Table 2

[0055]

[0056] Note: t1 is the self-extinguishing time after 10 seconds of the first ignition, and t2 is the self-extinguishing time after 10 seconds of the second ignition.

[0057] Note: t1 is the self extinguishing time after the first ignition for 10 seconds; t2 is the self extinguishing time after the second ignition for 10 seconds.

Claims

1. A method for preparing a halogen-free flame-retardant modified epoxy acrylic resin, characterized in that, Includes the following steps: S1: Dissolve epoxy resin in 50-150 mL of organic solvent, add flame retardant and polymerization inhibitor, stir, heat under reflux, then remove the organic solvent from the reactants by rotary evaporation, and freeze dry to remove the water from the reactants to obtain a pale yellow transparent solid. S2: Grind a pale yellow transparent solid with agate slurry, wash with organic solvent to remove unreacted reagents from the ground pale yellow transparent solid, and dry by rotary evaporation to obtain a pale yellow powder, named phosphorus-nitrogen halogen-free flame retardant modified epoxy acrylic resin. The epoxy resin is epoxidized m-phenylenediamine with the structure shown in Formula 1; The flame retardant is selected from phosphoric acid; The molar ratio of epoxy resin to phosphoric acid is (1.5-2.5):1; The reaction equation for the halogen-free flame-retardant modified epoxy acrylate resin is as follows: 。 2. The method for preparing the halogen-free flame-retardant modified epoxy acrylic resin according to claim 1, characterized in that, The organic solvent is selected from one or more of acetone, methyl ethyl ketone, cyclohexanone, and ethyl acetate.

3. The method for preparing the halogen-free flame-retardant modified epoxy acrylic resin according to claim 1, characterized in that, The polymerization inhibitor is selected from hydroquinone, o-methylhydroquinone, p-hydroxyanisole, p-benzoquinone, and 2,6-hydroxybenzoquinone. Second Uncle Ding Ji 4 One or more of methylphenols.

4. The method for preparing the halogen-free flame-retardant modified epoxy acrylate resin according to claim 1, characterized in that, The polymerization inhibitor accounts for 0.1% of the total mass of epoxy resin and phosphoric acid.

5. The method for preparing the halogen-free flame-retardant modified epoxy acrylate resin according to claim 1, characterized in that, The temperature of the heating reflux is 50–70°C.

6. A halogen-free flame-retardant modified epoxy acrylate resin prepared by the method according to any one of claims 1 to 5.

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