A kind of sepiolite-based flame retardant and preparation method thereof

Abstract

The present invention relates to the field of flame retardants, and provides a sepiolite-based flame retardant and a preparation method thereof. The sepiolite-based flame retardant comprises the following raw materials by weight: 30-50 parts of antimony trioxide, 10-20 parts of modified sepiolite, 4-10 parts of a heat stabilizer, 10-20 parts of methyl silicone oil, and 0.5-4 parts of a dispersant. The sepiolite-based flame retardant provided by the present invention has good flame retardancy and smoke suppression, and has good commercial application value.

Description

Technical Field

[0001] The invention relates to the field of flame retardants, and in particular to a sepiolite-based flame retardant and a preparation method thereof. Background Art

[0002] With the increasing global awareness of safety and environmental protection, the importance of flame retardancy and fire prevention is self-evident. People's requirements for fire safety and flame retardant materials are becoming higher and higher, and low-smoke, low-toxic environmentally friendly flame retardants are becoming more and more popular.

[0003] Compared with traditional flame retardant systems, the flame retardancy of clay minerals on polymers is mainly reflected in the barrier effect of the composite material in the process of burning to form a carbon layer. Sepiolite, as a natural and environmentally friendly mineral material, has a unique nanostructure, a large specific surface area, a uniform pore size and abundant active sites, which gives it good adsorption properties, and thus has certain flame retardancy and excellent smoke suppression. It can also improve the mechanical properties of composite materials to a certain extent, making it widely concerned in the field of flame retardants.

[0004] Although sepiolite has the above-mentioned advantages in the field of flame retardants, there are still some unresolved problems. For example, sepiolite itself is very brittle, which may cause it to crack or break during use, thus affecting the flame retardant effect of sepiolite; and sepiolite is prone to agglomeration and has poor dispersion performance, resulting in poor compatibility with polymer materials, affecting its flame retardant performance.

[0005] Patent CN 110615919A discloses a low-smoke modified halogen-free flame retardant and a preparation method thereof. The flame retardant includes components such as magnesium hydroxide particles, dolomite powder, clay and sepiolite powder. By adding dolomite powder and sepiolite powder and fully stirring and mixing them with the raw materials, the combustion of combustibles can be effectively prevented during the combustion process, the performance of the flame retardant is improved, and a good smoke suppression effect is achieved. However, the application does not solve the problem of high brittleness and poor dispersibility of sepiolite powder, resulting in certain hidden dangers in the long-term effectiveness of the flame retardant.

[0006] Therefore, there is an urgent need in the market for a sepiolite-based flame retardant with good flame retardancy and smoke suppression. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention uses antimony trioxide as the main component, adds modified sepiolite, a heat stabilizer, methyl silicone oil and a dispersant to synthesize a sepiolite-based flame retardant with good flame retardancy and smoke suppression.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] On one hand, the present invention provides a sepiolite-based flame retardant, which comprises the following raw materials by weight: 30-50 parts of antimony trioxide, 10-20 parts of modified sepiolite, 4-10 parts of heat stabilizer, 10-20 parts of methyl silicone oil, and 0.5-4 parts of dispersant.

[0010] In some embodiments of the present invention, the method for preparing the modified sepiolite comprises the following steps:

[0011] (1) adding sepiolite to deionized water, stirring at 155-160° C. for 7-9 hours, drying, adding to a hydrochloric acid aqueous solution, stirring for 7-9 hours, washing, and drying to obtain product 1 for later use;

[0012] (2) adding trimethoxyphenylsilane to an ethanol aqueous solution, stirring, adding the product 1 of step (1), stirring at 60-80° C. for 6-8 h, filtering, washing, and drying to obtain a product 2 for later use;

[0013] (3) Add phytic acid, polyaspartic acid and urea to deionized water, stir, add the product 2 of step (2), stir at 85-95° C. for 1.5-2.5 h, filter, dry and grind to obtain modified sepiolite.

[0014] Wherein, in the step (2), the mass ratio of product 1 to trimethoxyphenylsilane is 1:(0.05-0.07).

[0015] In some embodiments of the present invention, in step (1), the particle size of the sepiolite is 150-250 mesh.

[0016] Preferably, in step (1), the particle size of the sepiolite is 200 mesh.

[0017] The applicant selected the sepiolite in this particle size range because it has the advantages of high density, high heat resistance, high corrosion resistance and good durability, and can have better flame retardant and smoke suppression effects.

[0018] In some embodiments of the present invention, in step (3), the mass ratio of product 2, phytic acid, polyaspartic acid and urea is 1:(7.5-8.5):(1.5-2.5):(0.8-1.2).

[0019] Preferably, in step (3), the mass ratio of product 2, phytic acid, polyaspartic acid and urea is 1:8:2:1.

[0020] Sepiolite has a large specific surface area, good smoke suppression and flame retardancy. However, sepiolite is very brittle, which may cause cracks or breaks during use, thus affecting its flame retardant effect. In addition, because it is easy to agglomerate and has poor dispersion performance, its compatibility with polymer materials is poor, affecting its flame retardant properties.

[0021] On the one hand, the applicant firstly used the inorganic method of hydrothermal and acid leaching and the organic method of trimethoxyphenylsilane to jointly modify the sepiolite, thereby improving the dispersion performance of the sepiolite and enhancing the adsorption performance of the sepiolite, thereby improving the smoke suppression performance of the sepiolite; on the other hand, the applicant used phytic acid, polyaspartic acid and urea to modify the organic-inorganic jointly modified sepiolite (product 2), and the H in the phytic acid structure + Can replace Mg in the sepiolite structure 2+ , which improves the brittleness of the modified sepiolite. Polyaspartic acid, as an amino acid polymer, has a long-chain structure, fewer branches and a methylene chain structure, and has good flexibility. Phytic acid, polyaspartic acid and sepiolite can form a looser cross-linking structure, which improves the brittleness of the sepiolite and enhances the stability of the synthesized modified sepiolite, which can have a more lasting flame retardant and smoke suppression effect. Furthermore, phytic acid contains the element P, and polyaspartic acid and urea contain the element N, which can play a synergistic flame retardant role of N and P, thereby improving the flame retardant properties of the modified sepiolite.

[0022] In some embodiments of the present invention, the heat stabilizer is a mixture of zinc borate and modified cerium oxide.

[0023] In some embodiments of the present invention, the mass ratio of the zinc borate to the modified cerium oxide is 1:(2-4).

[0024] Preferably, the mass ratio of the zinc borate to the modified cerium oxide is 1:3.

[0025] In some embodiments of the present invention, the method for preparing the modified cerium oxide comprises the following steps:

[0026] 1) adding cerium nitrate hexahydrate into deionized water, stirring and then adding dropwise into a polyvinyl pyrrolidone aqueous solution, heating to 85-95° C., stirring, adding a sodium hydroxide aqueous solution to adjust the pH to 7-8, stirring, centrifuging, washing, and drying to obtain a product for later use;

[0027] 2) adding demethoxycurcumin to dimethyl sulfoxide, stirring and then adding dropwise to a polyvinyl pyrrolidone aqueous solution, stirring, adding the product of step 1), stirring, centrifuging, washing, and drying to obtain modified cerium dioxide.

[0028] Wherein, in the step 1), the mass ratio of cerium nitrate hexahydrate to polyvinyl pyrrolidone in the polyvinyl pyrrolidone aqueous solution is 1:(3.4-4).

[0029] In some embodiments of the present invention, in step 2), the mass ratio of demethoxycurcumin to the product is 1:(2.5-3.5).

[0030] Preferably, in the step 2), the mass ratio of demethoxycurcumin to the product is 1:3.

[0031] Cerium dioxide, as a rare earth oxide, has good thermal stability due to its special outer electron structure. It is a commonly used thermal stabilizer. However, cerium dioxide has the disadvantage of being easy to agglomerate, which will seriously affect its thermal stability.

[0032] The applicant uses cerium dioxide as the main component and polyvinyl pyrrolidone aqueous solution as a dispersant, and adopts a one-pot method to prepare the product, so that the cerium dioxide has good dispersibility. Furthermore, the applicant introduces demethoxycurcumin to prepare modified cerium dioxide. Demethoxycurcumin has good thermal stability and antioxidant properties, which can improve the thermal stability and antioxidant properties of the flame retardant, thereby effectively improving the overall flame retardant properties of the flame retardant.

[0033] In some embodiments of the present invention, the dispersant is ethylene bisstearamide or oleamide.

[0034] Another aspect of the present invention further provides a method for preparing the sepiolite-based flame retardant described in the above technical solution, comprising the following steps:

[0035] Antimony trioxide, modified sepiolite, heat stabilizer, methyl silicone oil and dispersant are mixed, stirred for 1.5-2.5 hours, and ball-milled for 20-40 minutes to obtain a sepiolite-based flame retardant.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention uses antimony trioxide as the main component, adds modified sepiolite, a heat stabilizer, methyl silicone oil and a dispersant to synthesize a sepiolite-based flame retardant. Through the synergistic effect of the components, the sepiolite-based flame retardant has the advantages of high flame retardancy and high smoke suppression.

[0038] (2) The present invention firstly adopts inorganic and organic methods to jointly modify the sepiolite, thereby improving the dispersion performance of the sepiolite and enhancing the smoke suppression performance of the sepiolite, and then introduces phytic acid, polyaspartic acid and urea for modification, thereby improving the brittleness of the sepiolite and enhancing the flame retardancy and smoke suppression performance.

[0039] (3) The present invention uses cerium dioxide as the main component, polyvinyl pyrrolidone as the dispersant, and then introduces demethoxycurcumin to prepare modified cerium dioxide, so that the modified cerium dioxide has good thermal stability and antioxidant properties.

[0040] (4) The sepiolite-based flame retardant prepared by the present invention has good flame retardancy and smoke suppression, can be widely used in the field of flame retardants, and has good commercial application value. DETAILED DESCRIPTION

[0041] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0042] In the following embodiments and comparative examples, except for modified sepiolite and modified cerium oxide, the other compound monomers and related reagents used can be purchased from the market. Among them, the particle size of sepiolite is 100 mesh and 200 mesh, both purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd.; polyaspartic acid was purchased from Pandex (Shanghai) International Trading Co., Ltd.; methyl silicone oil was purchased from Shandong Juneng Chemical Co., Ltd.; polyvinyl chloride resin was purchased from Jinan Xiangfeng Weiye Chemical Co., Ltd.

[0043] Preparation Example 1

[0044] The synthetic method of modified sepiolite A comprises the following steps:

[0045] (1) 20 g of sepiolite was added to 200 ml of deionized water, stirred at 158° C. for 8 h, dried at 60° C. for 24 h, added to 150 ml of a 10 wt % hydrochloric acid aqueous solution, stirred for 8 h, washed with deionized water until pH = 7, and dried at 60° C. for 24 h to obtain product 1 for standby use, wherein the particle size of the sepiolite was 200 mesh;

[0046] (2) Add 0.6 g of trimethoxyphenylsilane to 100 ml of 95 wt% ethanol aqueous solution, stir for 30 min, add 10 g of the product 1 of step (1), stir at 70° C. for 7 h, wash with deionized water until pH = 7, filter, and dry at 60° C. for 24 h to obtain product 2 for later use;

[0047] (3) Add 40 g of phytic acid, 10 g of polyaspartic acid and 5 g of urea to 300 ml of deionized water, stir for 2 h, add 5 g of the product 2 of step (2), stir at 90 ° C for 2 h, filter, dry at 60 ° C for 12 h, and grind to obtain modified sepiolite A.

[0048] Preparation Example 2

[0049] The specific implementation method of modified sepiolite B is the same as that of modified sepiolite A, except that in step (1), the particle size of the sepiolite is 100 mesh.

[0050] Preparation Example 3

[0051] The specific implementation method of modified sepiolite C is the same as that of modified sepiolite A, except that in step (3), the mass of phytic acid is replaced with 36.5 g.

[0052] Preparation Example 4

[0053] The specific implementation method of modified sepiolite D is the same as that of modified sepiolite A, except that in step (3), the mass of polyaspartic acid is replaced by 6 g.

[0054] Preparation Example 5

[0055] The specific implementation method of modified sepiolite E is the same as that of modified sepiolite A, except that in step (3), the mass of urea is replaced by 3 g.

[0056] Preparation Example 6

[0057] The synthesis method of modified cerium oxide A comprises the following steps:

[0058] 1) 11 g of cerium nitrate hexahydrate was added to 250 ml of deionized water, stirred for 30 min, then added dropwise to 200 ml of 0.2 g / ml polyvinyl pyrrolidone aqueous solution, heated to 90° C., stirred for 15 min, 1 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.8, stirred for 3 h, centrifuged, washed with deionized water 3 times, and dried at 60° C. for 12 h to obtain the product for use;

[0059] 2) 3 g of demethoxycurcumin was added to 50 ml of dimethyl sulfoxide, stirred for 30 min, then added dropwise to 200 ml of 0.2 g / ml polyvinyl pyrrolidone aqueous solution, stirred for 6 h, 9 g of the product of step 1) was added, stirred for 1 h, centrifuged, washed with deionized water 3 times, and dried at 60° C. for 12 h to obtain modified cerium oxide A.

[0060] Preparation Example 7

[0061] The specific implementation manner of modified cerium oxide B is the same as that of modified cerium oxide A, except that in step 2), the mass of demethoxycurcumin is replaced with 2.2 g.

[0062] Example 1

[0063] A sepiolite-based flame retardant comprises the following raw materials by weight: 40 parts of antimony trioxide, 15 parts of modified sepiolite A, 7 parts of a heat stabilizer, 15 parts of methyl silicone oil, and 2.25 parts of ethylene bisstearamide.

[0064] The heat stabilizer is a mixture of zinc borate and modified cerium oxide A, and the mass ratio of zinc borate to modified cerium oxide A is 1:3.

[0065] The preparation method of the sepiolite-based flame retardant in this embodiment comprises the following steps:

[0066] Antimony trioxide, modified sepiolite A, a heat stabilizer, methyl silicone oil and ethylene bisstearamide were mixed, stirred for 2 hours, and ball-milled for 30 minutes to obtain a sepiolite-based flame retardant.

[0067] Example 2

[0068] A sepiolite-based flame retardant comprises the following raw materials by weight: 30 parts of antimony trioxide, 15 parts of modified sepiolite A, 4 parts of a heat stabilizer, 10 parts of methyl silicone oil and 0.5 parts of oleic acid amide.

[0069] The heat stabilizer is a mixture of zinc borate and modified cerium oxide A, and the mass ratio of zinc borate to modified cerium oxide A is 1:2.

[0070] The preparation method of the sepiolite-based flame retardant in this embodiment comprises the following steps:

[0071] Antimony trioxide, modified sepiolite A, a heat stabilizer, methyl silicone oil and oleic acid amide were mixed, stirred for 1.5 hours, and ball-milled for 20 minutes to obtain a sepiolite-based flame retardant.

[0072] Example 3

[0073] A sepiolite-based flame retardant comprises the following raw materials by weight: 50 parts of antimony trioxide, 15 parts of modified sepiolite A, 10 parts of a heat stabilizer, 20 parts of methyl silicone oil, and 4 parts of ethylene bisstearamide.

[0074] The heat stabilizer is a mixture of zinc borate and modified cerium oxide A, and the mass ratio of zinc borate to modified cerium oxide A is 1:4.

[0075] The preparation method of the sepiolite-based flame retardant in this embodiment comprises the following steps:

[0076] Antimony trioxide, modified sepiolite A, a heat stabilizer, methyl silicone oil and ethylene bisstearamide were mixed, stirred for 2.5 hours, and ball-milled for 40 minutes to obtain a sepiolite-based flame retardant.

[0077] Example 4

[0078] A sepiolite-based flame retardant comprises the following raw materials by weight: 35 parts of antimony trioxide, 10 parts of modified sepiolite A, 7 parts of a heat stabilizer, 12 parts of methyl silicone oil and 2 parts of oleamide.

[0079] The heat stabilizer is a mixture of zinc borate and modified cerium oxide A, and the mass ratio of zinc borate to modified cerium oxide A is 1:3.

[0080] The preparation method of the sepiolite-based flame retardant in this embodiment is the same as that in Embodiment 1.

[0081] Example 5

[0082] A sepiolite-based flame retardant comprises the following raw materials by weight: 45 parts of antimony trioxide, 20 parts of modified sepiolite A, 7 parts of a heat stabilizer, 17 parts of methyl silicone oil, and 3 parts of ethylene bisstearamide.

[0083] The heat stabilizer is a mixture of zinc borate and modified cerium oxide A, and the mass ratio of zinc borate to modified cerium oxide A is 1:3.

[0084] The preparation method of the sepiolite-based flame retardant in this embodiment is the same as that in Embodiment 1.

[0085] Example 6

[0086] This embodiment provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified sepiolite B replaces modified sepiolite A in equal amounts.

[0087] Example 7

[0088] This embodiment provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified sepiolite C replaces modified sepiolite A in equal amounts.

[0089] Example 8

[0090] This embodiment provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified sepiolite D replaces modified sepiolite A in equal amounts.

[0091] Example 9

[0092] This embodiment provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified sepiolite E replaces modified sepiolite A in equal amounts.

[0093] Example 10

[0094] This embodiment provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified cerium oxide B replaces modified cerium oxide A in equal amounts.

[0095] Comparative Example 1

[0096] This comparative example provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that an equal amount of sepiolite is used to replace the modified sepiolite A, and the particle size of the sepiolite is 200 mesh.

[0097] Comparative Example 2

[0098] This comparative example provides a sepiolite-based flame retardant and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of cerium oxide is used to replace the modified cerium oxide A.

[0099] Performance Testing

[0100] The flame retardancy and smoke suppression properties of the sepiolite-based flame retardants of the above Examples 1-10 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1.

[0101] The sepiolite-based flame retardants obtained in Examples 1-10 and Comparative Examples 1-2 were respectively added to polyvinyl chloride resin (the mass ratio of polyvinyl chloride resin to sepiolite-based flame retardant was 1:0.02, and the mass of polyvinyl chloride was 50 g), heated to 120°C, mixed at high speed for 2 hours, extruded and granulated to obtain a composite material, and the composite material was tested for flame retardancy and smoke suppression to determine the flame retardancy and smoke suppression of the sepiolite-based flame retardant.

[0102] (1) Flame retardancy

[0103] Referring to the flame retardancy test standard of GB / T 2408-1996, the flame retardancy of V-0 grade is better than that of V-1 grade.

[0104] (2) Smoke suppression

[0105] The test is carried out in accordance with the smoke density test standard GB / T8323-2008. The lower the smoke concentration, the better the smoke suppression performance.

[0106] Table 1

[0107]

[0108]

[0109] It can be seen from the data in Table 1 that the flame retardant level and smoke concentration of the composite materials in Examples 1-5 of the present invention are both good results, that is, the sepiolite-based flame retardant has good flame retardancy and smoke suppression as a whole. Among them, Example 6 changes the particle size of sepiolite, which significantly reduces the smoke suppression performance of the modified sepiolite, but has little effect on the flame retardancy. Examples 7-9 respectively change the addition ratio of the main components in the synthesis process of the modified sepiolite, so that the brittleness and dispersibility of the modified sepiolite are not well improved, resulting in a significant decrease in the flame retardancy and smoke suppression of the sepiolite-based flame retardant; Example 10 changes the modification ratio of demethoxycurcumin to cerium oxide in the modified cerium oxide, so that the heat resistance of cerium oxide is not well improved, which leads to a certain degree of decrease in the flame retardancy of the sepiolite-based flame retardant, but has little effect on the smoke suppression; Comparative Examples 1-2 respectively use sepiolite and cerium oxide to replace modified sepiolite A and modified cerium oxide A in equal amounts, and the test finds that the flame retardancy and smoke suppression of the sepiolite-based flame retardant show poor results.

[0110] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A sepiolite-based flame retardant, characterized in that: The sepiolite-based flame retardant comprises the following raw materials by weight: 30-50 parts of antimony trioxide, 10-20 parts of modified sepiolite, 4-10 parts of heat stabilizer, 10-20 parts of methyl silicone oil, and 0.5-4 parts of dispersant; The preparation method of the modified sepiolite comprises the following steps: (1) Add sepiolite to deionized water, stir at 155-160° C. for 7-9 hours, dry, add to aqueous hydrochloric acid solution, stir for 7-9 hours, wash, dry, and obtain product 1 for later use; (2) adding trimethoxyphenylsilane to an ethanol aqueous solution, stirring, adding the product 1 of step (1), stirring at 60-80° C. for 6-8 h, filtering, washing, and drying to obtain the product 2 for later use; (3) adding phytic acid, polyaspartic acid and urea to deionized water, stirring, adding the product 2 of step (2), stirring at 85-95° C. for 1.5-2.5 h, filtering, drying and grinding to obtain modified sepiolite; In the step (3), the mass ratio of product 2, phytic acid, polyaspartic acid and urea is 1: (7.5-8.5): (1.5-2.5): (0.8-1.2); The heat stabilizer is a mixture of zinc borate and modified cerium oxide; The preparation method of the modified cerium oxide comprises the following steps: 1) Add cerium nitrate hexahydrate to deionized water, stir and then add dropwise to polyvinyl pyrrolidone aqueous solution, heat to 85-95°C, stir, add sodium hydroxide aqueous solution to adjust pH=7-8, stir, centrifuge, wash, dry, and obtain the product for use; 2) adding demethoxycurcumin to dimethyl sulfoxide, stirring and then dropping into a polyvinyl pyrrolidone aqueous solution, stirring, adding the product of step 1), stirring, centrifuging, washing, and drying to obtain modified cerium dioxide; In the step 2), the mass ratio of demethoxycurcumin to the product is 1:(2.5-3.5).

2. The sepiolite-based flame retardant according to claim 1, characterized in that: In the step (1), the particle size of the sepiolite is 150-250 mesh.

3. The sepiolite-based flame retardant according to claim 1, characterized in that: The mass ratio of the zinc borate to the modified cerium oxide is 1:(2-4).

4. The sepiolite-based flame retardant according to claim 1, characterized in that: The dispersant is ethylene bis stearamide or oleamide.

5. A method for preparing the sepiolite-based flame retardant according to any one of claims 1 to 4, characterized in that: The following steps are involved: Antimony trioxide, modified sepiolite, heat stabilizer, methyl silicone oil and dispersant are mixed, stirred for 1.5-2.5 hours, and ball-milled for 20-40 minutes to obtain a sepiolite-based flame retardant.

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