A polymeric flame retardant and its preparation method and application

Abstract

The present invention provides a polymeric flame retardant and a preparation method and application thereof, the polymeric flame retardant of the polymer of formula I. Compared with the flame retardant formed by compounding piperazine pyrophosphate and melamine polyphosphate / melamine pyrophosphate, the polymeric flame retardant of the present invention has lower water solubility and higher precipitation resistance, and the product has a weakly alkaline pH value and is less corrosive to metals such as screws.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a polymeric flame retardant and a preparation method and application thereof. Background Art

[0002] The halogen-free intumescent flame retardant compounded with piperazine pyrophosphate and melamine polyphosphate / melamine pyrophosphate has the advantages of low addition amount and high flame retardant performance compared with the flame retardant of ammonium polyphosphate system, so it has been widely used in polyolefin plastics such as polyethylene and polypropylene, and is a research hotspot in the field of halogen-free flame retardant materials. However, due to the characteristics of low pH, high water solubility and easy moisture absorption, piperazine pyrophosphate has the problems of corroding the screw, easy precipitation, and easy agglomeration during storage. Although the above problems have been improved after compounding with melamine polyphosphate / melamine pyrophosphate, the problem of simply physically mixing the product always exists.

[0003] Related technologies also mention that a weakly acidic piperazine pyrophosphate flame retardant can be obtained by adding an alkaline nucleating agent to the reaction. Although this process can increase the pH value of the product, it is still acidic and cannot change the problem that piperazine pyrophosphate is easily hydrolyzed and absorbs moisture to form agglomerates. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the first aspect of the present invention provides a polymer of formula I.

[0005] The second aspect of the present invention provides a method for preparing the polymer of formula I.

[0006] The third aspect of the present invention provides a polymeric flame retardant comprising the polymer of formula I.

[0007] The fourth aspect of the present invention provides a plastic comprising the polymer of formula I and / or the polymeric flame retardant.

[0008] The fifth aspect of the present invention proposes an application of the polymer of formula I and / or the polymeric flame retardant in flame retardant materials.

[0009] According to a first aspect of the present invention, a polymer of formula I is provided:

[0010]

[0011] Wherein, M is a basic capping agent; m / n=(1-3):1.

[0012] According to a second aspect of the present invention, a method for preparing the polymer of formula I is provided, comprising the following steps:

[0013] Under vacuum, piperazine diphosphate salt, melamine orthophosphate salt and antioxidant are mixed, heated to react, and after cooling, an alkaline capping agent is added to carry out a capping reaction to obtain the polymer of formula I.

[0014] In some embodiments of the present invention, the vacuum degree of the vacuum is -0.1 MPa to -0.05 MPa.

[0015] In some preferred embodiments of the present invention, the temperature of the temperature-raising reaction is 200° C. to 300° C. and the time is 5 h to 12 h.

[0016] In some more preferred embodiments of the present invention, the temperature of the end-capping reaction is 120° C. to 180° C. and the time is 0.5 h to 2 h.

[0017] In some more preferred embodiments of the present invention, the mass of the antioxidant is 0.1% to 1% of the total mass of the piperazine diphosphate salt and the melamine orthophosphate salt.

[0018] In some more preferred embodiments of the present invention, the antioxidant includes at least one of a phenolic antioxidant, a phosphorus antioxidant or a thioether antioxidant.

[0019] In some more preferred embodiments of the present invention, the mass of the alkaline capping agent is 0.1% to 2% of the total mass of the piperazine diphosphate salt and the melamine orthophosphate salt.

[0020] In some more preferred embodiments of the present invention, the alkaline capping agent includes at least one of ammonia, melamine or urea.

[0021] In some more preferred embodiments of the present invention, the method for preparing the polymer of formula I comprises using a reactor with vacuum extraction; preferably, the reactor with vacuum extraction comprises at least one of a twin-screw extruder, a double-cone dryer, a kneader dryer, a paddle dryer, a vertical stirring dryer or a rotary kiln dryer.

[0022] In some more preferred embodiments of the present invention, the preparation method of the piperazine diphosphate salt comprises the following steps: adding phosphoric acid dropwise to a piperazine aqueous solution and heating the solution to obtain the product; preferably, the temperature of the heating reaction is 50°C to 100°C, and the time is 1h to 12h; preferably, the molar ratio of the piperazine to the phosphoric acid is 1:(2.0 to 2.2); preferably, in the piperazine aqueous solution, the mass of water is 2 to 3 times the total mass of the piperazine and phosphoric acid; preferably, the phosphoric acid is added dropwise for 0.5h to 2h.

[0023] In some more preferred embodiments of the present invention, the preparation method of the melamine orthophosphate salt comprises the following steps: adding phosphoric acid dropwise to a melamine aqueous solution and heating the solution to obtain the melamine salt; preferably, the temperature of the heating reaction is 40°C to 100°C, and the time is 4h to 12h; preferably, the molar ratio of the melamine to the phosphoric acid is 1:(1.0 to 1.2); preferably, in the melamine aqueous solution, the mass of water is 2 to 3 times the total mass of the melamine and phosphoric acid; preferably, the phosphoric acid is added dropwise for 0.5h to 2h.

[0024] According to a third aspect of the present invention, a polymeric flame retardant comprising the polymer of formula I is provided.

[0025] According to a fourth aspect of the present invention, a plastic composition comprising the polymer of formula I and / or the polymeric flame retardant is provided.

[0026] According to a fifth aspect of the present invention, a use of the polymer of formula I and / or the polymeric flame retardant in flame retardant materials is proposed.

[0027] The beneficial effects of the present invention are as follows: compared with the flame retardant formed by compounding piperazine pyrophosphate and melamine polyphosphate / melamine pyrophosphate, the polymeric flame retardant of the present invention has lower water solubility and higher precipitation resistance, and the product has a weakly alkaline pH value and is less corrosive to metals such as screws. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0029] Figure 1 This is the TG diagram of the polymeric flame retardant of Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment prepares a polymeric flame retardant, and the specific process is as follows:

[0033] 1) 86.14 kg of piperazine was added to a reactor containing 700 kg of water, stirring was started, and then 242.09 kg of 85% phosphoric acid was slowly added dropwise over a period of 0.5 hour. After addition, the temperature was raised to 80° C., the reaction was continued for 4 hours, and the temperature was lowered and centrifuged and dried to obtain 253.91 kg of piperazine diphosphate;

[0034] 2) 126.12 kg of melamine was added to a reactor containing 600 kg of water, stirring was started, and then 126.81 kg of 85% phosphoric acid was slowly added dropwise for 1 hour, heated to 90° C., reacted for 2 hours, cooled, and centrifuged and dried to obtain 212.90 kg of melamine orthophosphate;

[0035] 3) 141.06 kg of piperazine diphosphate, 62.75 kg of melamine orthophosphate and 0.2 kg of antioxidant trinonylphenyl phosphite were mixed and then added to a double-cone dryer with vacuum, the vacuum was turned on, the vacuum degree was -0.08 MPa, and then the temperature was raised to 250 ° C for high-temperature dehydration, the reaction time was 6 hours, and then the vacuum was turned off and the temperature was lowered to 150 ° C, 1.0 kg of ammonia was introduced, and the temperature was maintained at 150 ° C for reaction for 0.5 hours, and the temperature was cooled to room temperature for discharge, and after crushing, 171.73 kg of a weakly alkaline and precipitation-resistant polymeric flame retardant was obtained.

[0036] The TG diagram of the prepared polymeric flame retardant is shown in Figure 1 shown.

[0037] from Figure 1 It can be seen that the 1% decomposition temperature of the product is 276.01°C, and there is no small peak of piperazine diphosphate and melamine orthophosphate residues in the front, indicating that the two have polymerized at this time.

[0038] Example 2

[0039] This embodiment prepares a polymeric flame retardant, and the specific process is as follows:

[0040] 1) 86.14 kg of piperazine was added to a reactor containing 950 kg of water, stirring was started, and then 230.56 kg of 85% phosphoric acid was slowly added dropwise over 1.5 hours. After the addition, the temperature was raised to 60° C., the reaction was continued for 6 hours, and the temperature was lowered and centrifuged and dried to obtain 239.7 kg of piperazine diphosphate;

[0041] 2) 126.12 kg of melamine was added to a reaction kettle containing 600 kg of water, stirring was started, and then 132.57 kg of 85% phosphoric acid was slowly added dropwise for 2 hours, heated to 60° C., reacted for 6 hours, cooled, and centrifuged and dried to obtain 201.70 kg of melamine orthophosphate;

[0042] 3) 141.06 kg of piperazine diphosphate, 44.82 kg of melamine orthophosphate and 1.85 kg of antioxidant 2,6-di-tert-butyl-p-cresol are mixed evenly and then added to a vertical reactor with vacuum, the vacuum is turned on, the vacuum degree is -0.09 MPa, and then the temperature is raised to 280°C for high-temperature dehydration, the reaction time is 4 hours, and then the vacuum is turned off and the temperature is lowered to 180°C, 1.82 kg of urea is introduced, the temperature is maintained at 180°C for reaction for 1 hour, the temperature is lowered to room temperature for discharge, and 164.48 kg of a weakly alkaline and precipitation-resistant polymeric flame retardant is obtained after crushing.

[0043] Example 3

[0044] This embodiment prepares a polymeric flame retardant, and the specific process is as follows:

[0045] 1) 86.14 kg of piperazine was added to a reactor containing 800 kg of water, stirring was started, and then 253.62 kg of 85% phosphoric acid was slowly added dropwise over 2 hours. After the addition, the temperature was raised to 98° C., reacted for 2 hours, cooled, and centrifuged and dried to obtain 248.16 kg of piperazine diphosphate;

[0046] 2) 126.12 kg of melamine was added to a reactor containing 750 kg of water, stirring was started, and then 138.34 kg of 85% phosphoric acid was slowly added dropwise for 1.5 hours, heated to 75° C., reacted for 4 hours, cooled, and centrifuged and dried to obtain 212.90 kg of melamine orthophosphate;

[0047] 3) 141.06 kg of piperazine diphosphate, 93.33 kg of melamine orthophosphate and 1.17 kg of antioxidant dilauryl thiodipropionate were mixed evenly and then added to a paddle dryer with vacuum, the vacuum was turned on, the vacuum degree was -0.08 MPa, and then the temperature was raised to 220° C. for high-temperature dehydration, the reaction time was 10 hours, and then the vacuum was turned off and the temperature was lowered to 120° C., 2.34 kg of melamine was introduced, the temperature was kept at 120° C. for reaction for 2 hours, the temperature was cooled to room temperature, and the material was discharged, and after crushing, 205.22 kg of a weakly alkaline and precipitation-resistant polymeric flame retardant was obtained.

[0048] Comparative Example 1:

[0049] Step 1 and step 2 are consistent with Example 1, and then the same proportion of piperazine diphosphate and cyanuric orthophosphate are dehydrated to form piperazine pyrophosphate and melamine pyrophosphate respectively, and then compounded to form a flame retardant.

[0050] Comparative Example 2:

[0051] Step 1 and step 2 are consistent with Example 1, and then the same proportion of piperazine diphosphate and melamine orthophosphate are dehydrated to form piperazine pyrophosphate and melamine polyphosphate respectively, and then compounded to form a flame retardant.

[0052] Comparative Example 3:

[0053] Step 1 and step 2 are consistent with Example 1, and step 3 is based on step 3 of Example 1, except that the operation of passing ammonia gas during the cooling stage is removed, and the temperature is directly lowered after the polymerization reaction is completed to form a flame retardant.

[0054] Comparative Example 4:

[0055] Step 1 and step 2 are consistent with Example 2, and then the same proportion of piperazine diphosphate and cyanuric orthophosphate are dehydrated to form piperazine pyrophosphate and melamine pyrophosphate respectively, and then compounded to form a flame retardant.

[0056] Comparative Example 5:

[0057] Step 1 and step 2 are consistent with Example 2, and then the same proportion of piperazine diphosphate and melamine orthophosphate are dehydrated to form piperazine pyrophosphate and melamine polyphosphate respectively, and then compounded to form a flame retardant.

[0058] Comparative Example 6:

[0059] Step 1 and step 2 are consistent with Example 3, and then the same proportion of piperazine diphosphate and cyanuric orthophosphate are dehydrated to form piperazine pyrophosphate and melamine pyrophosphate respectively, and then compounded to form a flame retardant.

[0060] Comparative Example 7:

[0061] Step 1 and step 2 are consistent with Example 3, and then the same proportion of piperazine diphosphate and melamine orthophosphate are dehydrated to form piperazine pyrophosphate and melamine polyphosphate respectively, and then compounded to form a flame retardant.

[0062] Test Example 1

[0063] The flame retardants prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were tested for water solubility and pH value, and the specific results are shown in Table 1:

[0064] Table 1

[0065]

[0066] The flame retardants prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were applied to PP to prepare flame-retardant PP materials. The specific raw material composition is shown in Table 2:

[0067] Table 2

[0068]

[0069]

[0070] The flame retardant PP materials in Table 2 were made into samples (samples 1 to 10 in sequence) and flame retardant performance tests and precipitation performance tests were carried out. The test results are shown in Table 3:

[0071] Table 3

[0072]

[0073] From the above test results, we can see that:

[0074] 1) Under the same ratio of piperazine diphosphate salt and melamine orthophosphate salt, the flame retardant produced by polymerization reaction has lower water solubility than the compounded flame retardant, and the pH value of the product is significantly increased and becomes weakly alkaline through the end-capping reaction;

[0075] 2) In addition, from the flame retardancy and weight loss results of the application in PP, the flame retardancy of the material produced by polymerization reaction is not much different from that of the compounded material. However, from the weight loss results, it can be clearly seen that the weight loss rate of the material produced by polymerization reaction is lower and its precipitation resistance is better.

[0076] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A polymer of formula I: ； in, M is an alkaline blocking agent; m / n=(1-3):1; the alkaline blocking agent includes at least one of ammonia, melamine or urea.

2. A method for preparing a polymer of formula (I) as claimed in claim 1, characterized in that: The following steps are involved: Under vacuum, piperazine diphosphate salt, melamine orthophosphate salt and antioxidant are mixed, heated to react, and after cooling, an alkaline end-capping agent is added to carry out an end-capping reaction to obtain the polymer of formula I; The alkaline blocking agent includes at least one of ammonia, melamine or urea; The mass of the alkaline capping agent is 0.1% to 2% of the total mass of the piperazine diphosphate salt and the melamine orthophosphate salt.

3. The method for preparing a polymer of formula (I) according to claim 2, characterized in that: The temperature of the temperature-raising reaction is 200° C. to 300° C., and the time is 5 h to 12 h.

4. The method for preparing a polymer of formula (I) according to claim 2, characterized in that: The temperature of the end-capping reaction is 120° C. to 180° C., and the time is 0.5 h to 2 h.

5. The method for preparing a polymer of formula (I) according to claim 2, characterized in that: The weight of the antioxidant is 0.1% to 1% of the total weight of the piperazine diphosphate salt and the melamine orthophosphate salt.

6. A polymeric flame retardant comprising the polymer of formula (I) as claimed in claim 1.

7. A plastic composition comprising a polymer of formula I as claimed in claim 1 or a polymeric flame retardant as claimed in claim 6.

8. Use of the polymer of formula I as claimed in claim 1 or the polymeric flame retardant as claimed in claim 6 in flame retardant materials.

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