A preparation method of flame retardant modified SEBS

Abstract

The invention relates to the technical field of SEBS, and discloses a method for preparing a flame retardant modified SEBS, wherein DOPO, methylvinyldichlorosilane, cyc, 3-butene-1-ol and the like are used as raw materials, and subjected to addition reaction and substitution reaction to obtain a flame retardant modifier, which is then grafted onto SEBS to obtain DOPO-based SEBS. SEBS, DOPO-based SEBS and the like are added into a blender, stirred and mixed, extruded and granulated, dried, hot pressed, and sampled to obtain a flame retardant modified SEBS. The invention utilizes the flame retardant elements of the flame retardant modifier to introduce it into SEBS, thereby increasing the flame retardant effect of SEBS, and utilizes the triene structure contained in the flame retardant modifier to graft with SEBS to form a larger cross-linked network structure, thereby increasing the mechanical properties of SEBS, and the flame retardant modified SEBS prepared by the invention has been verified to have good mechanical properties and flame retardant properties through experiments.

Description

Technical Field

[0001] The invention relates to the technical field of SEBS, in particular to a method for preparing flame-retardant modified SEBS. Background Art

[0002] Styrene-ethylene / butylene-styrene block copolymer (SEBS) is a new multi-purpose thermoplastic elastomer with excellent stability, heat resistance, weather resistance and other properties. It is widely used in electrical appliances, cables, automobile manufacturing, construction and other fields. However, in these fields, the requirements for the flame retardancy of the material are very strict, and SEBS is flammable, and will produce a large number of molten droplets when burning. The flame propagation speed is fast, which is not suitable for flame retardant applications, greatly limiting its application range. Therefore, it is necessary to improve the flame retardant properties of SEBS.

[0003] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) is an environmentally friendly and highly active flame retardant modifier. Its PH bond reacts very actively with C=O, C=C and C≡C. It can introduce a variety of flame retardant elements, which react with each other to form a variety of DOPO-based flame retardants.

[0004] The patent application publication number CN101974196A discloses that white oil, magnesium hydroxide, APP, etc. are added to SEBS to prepare a high-oil-content thermoplastic elastomer SEBS flame-retardant composite material and its preparation method, which has good flame-retardant effect, but does not improve the mechanical properties. Summary of the invention

[0005] The purpose of the present invention is to overcome the technical defect of the existing SEBS being flammable, and to provide a method for preparing a flame retardant modified SEBS. A flame retardant modifier is prepared and applied to SEBS to improve the flame retardant properties and mechanical properties of SEBS.

[0006] The object of the present invention can be achieved by the following technical scheme: A method for preparing flame retardant modified SEBS, the preparation method comprising:

[0007] (1) Preparation of intermediate 1

[0008] Add DOPO and methylvinyldichlorosilane to toluene solvent, stir and mix evenly, then add AIBN, react at 75-85°C for 18-24h, after the reaction is completed, rotary evaporate, wash with ethanol, and dry to obtain intermediate 1;

[0009] Under the action of azobisisobutyronitrile (AIBN), DOPO reacts with methylvinyldichlorosilane to obtain intermediate 1. The reaction process is as follows:

[0010] ;

[0011] (2) Preparation of intermediate 2

[0012] Under nitrogen conditions, add Sec and intermediate 1 to toluene solvent, stir and disperse, heat to 70-80°C, and keep warm for 6-12 hours. After the reaction is completed, distill under reduced pressure, wash with deionized water, and dry to obtain intermediate 2;

[0013] The -OH on the Sec molecule undergoes a substitution reaction with the -Cl on the intermediate 1 molecule to obtain intermediate 2. The reaction process is as follows:

[0014] ;

[0015] (3) Preparation of flame retardant modifier

[0016] 3-Butene-1-ol and pyridine are added to a toluene solvent, stirred and dispersed, and then the intermediate 2 is added thereto, the temperature is raised to 70-85°C, and the reaction is carried out for 3-6 hours. After the reaction is completed, extraction is performed with ethyl acetate, washing with deionized water, rotary evaporation, and drying to obtain a flame retardant modifier;

[0017] Under the action of pyridine (py), 3-butene-1-ol and intermediate 2 undergo a second substitution reaction to obtain a flame retardant modifier. The reaction process is as follows:

[0018] ;

[0019] (4) Preparation of DOPO-based SEBS

[0020] Add SEBS, maleic anhydride and flame retardant modifier into xylene solvent, stir and disperse, heat to 130-140°C, add dicumyl peroxide, reflux for 2-5h, add ethanol for precipitation after the reaction, wash with ethanol, and dry to obtain DOPO-based SEBS;

[0021] Under the initiation of dicumyl peroxide, maleic anhydride and flame retardant modifier were grafted onto SEBS by solution method to obtain DOPO-based SEBS.

[0022] (5) Preparation of flame retardant modified SEBS

[0023] SEBS, DOPO-based SEBS, magnesium hydroxide and paraffin oil are added into a mixer, stirred and mixed, extruded and granulated by a twin-screw extruder, dried, hot-pressed by a flat vulcanizer, cold-pressed at room temperature, and sampled to obtain a flame-retardant modified SEBS.

[0024] Furthermore, in (1), the mass ratio of DOPO, methylvinyldichlorosilane, and AIBN is 3-4.2:1:0.059-0.1;

[0025] Furthermore, in (2), the mass ratio of Cyclic Acid to the intermediate 1 is 1:4-5.5.

[0026] Furthermore, in (3), the mass ratio of 3-butene-1-ol to intermediate 2 is 0.15-0.3:1.

[0027] Furthermore, in (4), the mass ratio of SEBS, maleic anhydride, flame retardant modifier and dicumyl peroxide is 1:0.1-0.2:0.1-0.5:0.1-0.2.

[0028] Furthermore, in (5), the mass ratio of SEBS, DOPO-based SEBS and magnesium hydroxide is 100:50-100:10-20.

[0029] Beneficial effects of the present invention:

[0030] 1. The present invention prepares a modified flame retardant, which contains a triene structure. When it is grafted with SEBS, it can produce more cross-linked network structures. When subjected to external force, the external force can be dispersed through the molecular chain, thereby achieving the purpose of improving the mechanical properties of SEBS.

[0031] 2. The modified flame retardant prepared by the present invention contains phosphorus, nitrogen and silicon. The non-flammable gas generated by the heating of nitrogen is used to dilute the concentration of flammable gas. The strong dehydrating substance generated by the heating of phosphorus is used to promote the dehydration of the material into carbon, thereby forming a dense carbon layer on the surface of the material. The glass-like substance generated by the heating of silicon is further covered on the surface of the material to isolate the material transfer and energy transport. The three work synergistically to jointly improve the flame retardant properties of the material.

[0032] 3. The modified flame retardant prepared by the present invention is introduced into SEBS with magnesium hydroxide, and the flame retardant effect of SEBS is jointly improved through the organic-inorganic synergistic flame retardancy, thereby expanding the application scope of SEBS, and having important application value in the SEBS field. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a SEM photograph of the residual carbon layer after the combustion test of Example 1. It can be found from the figure that the surface of the obtained carbon layer is closely arranged in a staggered manner horizontally and vertically, the carbon layer has high strength, and has a strong effect of isolating heat and combustible gas. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Embodiment 1

[0035] (1) 42 g of DOPO and 14 g of methylvinyldichlorosilane were added to 100 mL of toluene solvent and stirred to mix evenly. Then, 1.64 g of AIBN was added thereto and reacted at 75° C. for 20 h. After the reaction was completed, the mixture was rotary evaporated, washed with ethanol, and dried to obtain intermediate 1.

[0036] (2) Under nitrogen conditions, 13 g of Sec and 60 g of intermediate 1 were added to 150 mL of toluene solvent, stirred and dispersed, and the temperature was raised to 75°C. The reaction was kept warm for 12 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water, and dried to obtain intermediate 2.

[0037] (3) 6 g of 3-butene-1-ol and 8 mL of pyridine were added to 200 mL of toluene solvent, stirred and dispersed, and then 30 g of intermediate 2 was added thereto. The temperature was raised to 75° C. and the reaction was carried out for 6 h. After the reaction was completed, the mixture was extracted with ethyl acetate, washed with deionized water, rotary evaporated, and dried to obtain a flame retardant modifier.

[0038] (4) Add 50 g of SEBS, 5 g of maleic anhydride, and 5 g of flame retardant modifier into 200 mL of xylene solvent, stir and disperse, heat to 130 °C, add 8 g of diisopropylbenzene peroxide, reflux for 4 h, and after the reaction, add ethanol for precipitation, wash with ethanol, and dry to obtain DOPO-based SEBS.

[0039] (5) Add 80 g of SEBS, 40 g of DOPO-based SEBS, 8 g of magnesium hydroxide, and 30 g of paraffin oil into a mixer, stir and mix, extrude and granulate using a twin-screw extruder, set the front roller temperature to 195 °C, the rear roller temperature to 190 °C, dry, hot press using a flat vulcanizer, cold press at room temperature for 6 min, the hot pressing temperature to 180 °C, the hot pressing time to 4 min, and the pressure to 8 MPa, and prepare a sample to obtain a flame retardant modified SEBS. Embodiment 2

[0040] (1) Add 50 g of DOPO and 14 g of methylvinyldichlorosilane to 100 mL of toluene solvent and stir to mix evenly. Then add 1 g of AIBN and react at 80 °C for 24 h. After the reaction is completed, evaporate the mixture, wash with ethanol, and dry to obtain intermediate 1.

[0041] (2) Under nitrogen conditions, 13 g of Sec and 71.5 g of intermediate 1 were added to 150 mL of toluene solvent, stirred and dispersed, and the temperature was raised to 70°C. The reaction was kept warm for 10 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water, and dried to obtain intermediate 2.

[0042] (3) Add 6 g of 3-butene-1-ol and 10 mL of pyridine to 200 mL of toluene solvent, stir and disperse, then add 30 g of intermediate 2, heat to 75° C., react for 6 h. After the reaction is completed, extract with ethyl acetate, wash with deionized water, rotary evaporate, and dry to obtain a flame retardant modifier.

[0043] (4) Add 50 g of SEBS, 6 g of maleic anhydride, and 10 g of flame retardant modifier into 200 mL of xylene solvent, stir and disperse, heat to 135 °C, add 5 g of diisopropylbenzene peroxide, reflux for 5 h, and after the reaction, add ethanol for precipitation, wash with ethanol, and dry to obtain DOPO-based SEBS.

[0044] (5) Add 80 g of SEBS, 50 g of DOPO-based SEBS, 10 g of magnesium hydroxide, and 30 g of paraffin oil into a mixer, stir and mix, extrude and granulate using a twin-screw extruder, set the front roller temperature to 195 °C, the rear roller temperature to 185 °C, dry, hot press using a flat vulcanizer, cold press at room temperature for 6 min, the hot pressing temperature to 180 °C, the hot pressing time to 4 min, and the pressure to 8 MPa, and prepare a sample to obtain a flame retardant modified SEBS. Embodiment 3

[0045] (1) 58.8 g of DOPO and 14 g of methylvinyldichlorosilane were added to 100 mL of toluene solvent and stirred to mix evenly. Then, 0.82 g of AIBN was added thereto and reacted at 85° C. for 18 h. After the reaction was completed, the mixture was rotary evaporated, washed with ethanol, and dried to obtain intermediate 1.

[0046] (2) Under nitrogen conditions, 13 g of Sec and 52 g of intermediate 1 were added to 150 mL of toluene solvent, stirred and dispersed, and the temperature was raised to 80°C. The reaction was kept warm for 6 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water, and dried to obtain intermediate 2.

[0047] (3) 4.5 g of 3-butene-1-ol and 8 mL of pyridine were added to 200 mL of toluene solvent, stirred and dispersed, and then 30 g of intermediate 2 was added thereto. The temperature was raised to 85° C. and the reaction was carried out for 5 h. After the reaction was completed, the mixture was extracted with ethyl acetate, washed with deionized water, rotary evaporated, and dried to obtain a flame retardant modifier.

[0048] (4) Add 50 g of SEBS, 10 g of maleic anhydride, and 15 g of flame retardant modifier into 200 mL of xylene solvent, stir and disperse, heat to 140°C, add 10 g of diisopropylbenzene peroxide, reflux for 2 h, and after the reaction, add ethanol for precipitation, wash with ethanol, and dry to obtain DOPO-based SEBS.

[0049] (5) Add 80 g of SEBS, 60 g of DOPO-based SEBS, 12 g of magnesium hydroxide, and 30 g of paraffin oil into a mixer, stir and mix, extrude and granulate using a twin-screw extruder, set the front roller temperature to 190 °C, the rear roller temperature to 180 °C, dry, hot press using a flat vulcanizer, cold press at room temperature for 5 min, the hot pressing temperature to 180 °C, the hot pressing time to 4 min, and the pressure to 8 MPa, and prepare a sample to obtain a flame retardant modified SEBS. Embodiment 4

[0050] (1) 42 g of DOPO and 14 g of methylvinyldichlorosilane were added to 100 mL of toluene solvent and stirred to mix evenly. Then, 1 g of AIBN was added thereto and reacted at 75 °C for 24 h. After the reaction was completed, the mixture was rotary evaporated, washed with ethanol, and dried to obtain intermediate 1.

[0051] (2) Under nitrogen conditions, 13 g of Sec and 70 g of intermediate 1 were added to 150 mL of toluene solvent, stirred and dispersed, and the temperature was raised to 75°C. The reaction was kept warm for 8 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water, and dried to obtain intermediate 2.

[0052] (3) Add 6 g of 3-butene-1-ol and 10 mL of pyridine to 200 mL of toluene solvent, stir and disperse, then add 30 g of intermediate 2, heat to 70°C, react for 4 h. After the reaction, extract with ethyl acetate, wash with deionized water, rotary evaporate, and dry to obtain a flame retardant modifier.

[0053] (4) Add 50 g of SEBS, 8 g of maleic anhydride, and 20 g of flame retardant modifier into 200 mL of xylene solvent, stir and disperse, heat to 135 °C, add 6 g of diisopropylbenzene peroxide, reflux for 3 h, and after the reaction, add ethanol for precipitation, wash with ethanol, and dry to obtain DOPO-based SEBS.

[0054] (5) Add 80 g of SEBS, 70 g of DOPO-based SEBS, 14 g of magnesium hydroxide, and 30 g of paraffin oil into a mixer, stir and mix, extrude and granulate using a twin-screw extruder, set the front roller temperature to 200 °C, the rear roller temperature to 180 °C, dry, hot press on a flat vulcanizer, cold press at room temperature for 6 min, the hot pressing temperature to 180 °C, the hot pressing time to 2 min, and the pressure to 8 MPa, and prepare a sample to obtain a flame retardant modified SEBS. Embodiment 5

[0055] (1) Add 50 g of DOPO and 14 g of methylvinyldichlorosilane to 100 mL of toluene solvent and stir to mix evenly. Then add 1.5 g of AIBN and react at 80 °C for 20 h. After the reaction is completed, evaporate the mixture, wash with ethanol, and dry to obtain intermediate 1.

[0056] (2) Under nitrogen conditions, 13 g of Sec and 70 g of intermediate 1 were added to 150 mL of toluene solvent, stirred and dispersed, and the temperature was raised to 75°C. The reaction was kept warm for 10 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with deionized water, and dried to obtain intermediate 2.

[0057] (3) 9 g of 3-butene-1-ol and 6 mL of pyridine were added to 200 mL of toluene solvent and dispersed by stirring. Then, 30 g of intermediate 2 was added thereto. The temperature was raised to 75° C. and the reaction was carried out for 3 h. After the reaction was completed, the mixture was extracted with ethyl acetate, washed with deionized water, rotary evaporated, and dried to obtain a flame retardant modifier.

[0058] (4) Add 50 g of SEBS, 8 g of maleic anhydride, and 25 g of flame retardant modifier into 200 mL of xylene solvent, stir and disperse, heat to 135 °C, add 8 g of diisopropylbenzene peroxide, reflux for 4 h, and after the reaction, add ethanol for precipitation, wash with ethanol, and dry to obtain DOPO-based SEBS.

[0059] (5) Add 80 g of SEBS, 80 g of DOPO-based SEBS, 16 g of magnesium hydroxide, and 30 g of paraffin oil into a mixer, stir and mix, extrude and granulate using a twin-screw extruder, set the front roller temperature to 200 °C, the rear roller temperature to 190 °C, dry, hot press on a flat vulcanizer, cold press at room temperature for 4 min, hot press temperature to 180 °C, hot press time to 2 min, pressure to 8 MPa, prepare a sample, and obtain a flame retardant modified SEBS.

[0060] Comparative Example 1

[0061] The preparation method of the flame retardant modified SEBS provided in this comparative example is substantially the same as that of Example 1, with the main difference being that step (5) does not contain DOPO-based SEBS.

[0062] Refer to ASTM D635-77 to test the vertical burning level, the sample size is 127×12.7×4mm 3 .

[0063] Refer to GB / T2406-93 to test the limiting oxygen index, the sample size is 80×10×4mm 3 .

[0064] Table 1:

[0065] Vertical burning level (grade) Limiting oxygen index (%) Example 1 V-2 26.7 Example 2 V-1 29.4 Example 3 V-0 32.3 Example 4 V-0 34.0 Example 5 V-0 36.2 Comparative Example 1 No level 19.8

[0066] It can be seen from the data in the above table that the flame retardant modified SEBS prepared by the present invention has excellent flame retardant properties. Combined with the data of Comparative Example 1, it can be seen that after adding DOPO-based SEBS, the flame retardant properties of SEBS can be increased.

[0067] Refer to GB / T528-2009 to test the tensile strength.

[0068] Refer to GB / T529-2008 to test the tear strength.

[0069] Table 2:

[0070] Tensile strength (MPa) <![CDATA[Tear strength (kN·m -1 )]]> Example 1 7.53 22.0 Example 2 8.19 24.6 Example 3 8.96 28.3 Example 4 9.55 31.6 Example 5 9.08 30.9 Comparative Example 1 5.42 19.4

[0071] It can be seen from the data in the above table that the flame retardant modified SEBS prepared by the present invention has excellent mechanical properties. Combined with the data of Comparative Example 1, it can be seen that after adding DOPO-based SEBS, the larger cross-linked network structure contained therein can increase the mechanical properties of SEBS when subjected to external force.

[0072] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing flame retardant modified SEBS, characterized in that: The preparation method is: (1) Preparation of Intermediate 1 Add DOPO and methylvinyldichlorosilane to toluene solvent, stir and mix evenly, then add AIBN, react at 75-85°C for 18-24h, after the reaction is completed, rotary evaporate, wash with ethanol, and dry to obtain intermediate 1; (2) Preparation of Intermediate 2 Under nitrogen conditions, add cyc and intermediate 1 to toluene solvent, wherein the mass ratio of cyc to intermediate 1 is 1:4-5.5, stir and disperse, heat to 70-80°C, and keep warm for 6-12h. After the reaction is completed, distill under reduced pressure, wash with deionized water, and dry to obtain intermediate 2; (3) Preparation of flame retardant modifier 3-Butene-1-ol and pyridine are added to a toluene solvent, stirred and dispersed, and then the intermediate 2 is added thereto, wherein the mass ratio of 3-butene-1-ol to the intermediate 2 is 0.15-0.3:1, and the temperature is raised to react. After the reaction is completed, extraction is performed with ethyl acetate, washing with deionized water, rotary evaporation, and drying to obtain a flame retardant modifier; (4) Preparation of DOPO-based SEBS Add SEBS, maleic anhydride and flame retardant modifier into xylene solvent, stir and disperse, heat to 130-140°C, add dicumyl peroxide, reflux for 2-5h, add ethanol for precipitation after the reaction, wash with ethanol, and dry to obtain DOPO-based SEBS; (5) Preparation of flame retardant modified SEBS SEBS, DOPO-based SEBS, magnesium hydroxide and paraffin oil are added into a mixer, stirred and mixed, extruded and granulated by a twin-screw extruder, dried, hot-pressed by a flat vulcanizer, cold-pressed at room temperature, and sampled to obtain a flame-retardant modified SEBS.

2. The method for preparing the flame retardant modified SEBS according to claim 1, characterized in that: In the above (1), the mass ratio of DOPO, methylvinyldichlorosilane and AIBN is 3-4.2:1:0.059-0.

1.

3. The method for preparing the flame retardant modified SEBS according to claim 1, characterized in that: In the step (3), the reaction temperature is 70-85°C and the reaction time is 3-6h.

4. The method for preparing the flame retardant modified SEBS according to claim 1, characterized in that: In the above (4), the mass ratio of SEBS, maleic anhydride, flame retardant modifier and dicumyl peroxide is 1:0.1-0.2:0.1-0.5:0.1-0.

2.

5. The method for preparing the flame retardant modified SEBS according to claim 1, characterized in that: In the above (5), the mass ratio of SEBS, DOPO-based SEBS and magnesium hydroxide is 100:50-100:10-20.

Images