Intumescent flame retardant as well as preparation method and application thereof

Abstract

The invention discloses an intumescent flame retardant and a preparation method and application thereof.The intumescent flame retardant is a compound formed by combining a triazine compound and aminophosphonic acid through ionic bonds, the aminophosphonic acid compound contains phosphorus and nitrogen at the same time, the triazine compound is of a tertiary nitrogen-rich structure, and the tertiary nitrogen-rich structure is a nitrogen-rich structure. Therefore, the three-source integrated intumescent flame retardant can be prepared by combining the characteristics of the two, and the triazine compound can enable the phosphorus and nitrogen of the flame retardant to be balanced. The triazinyl compound is combined by ionic bonds, the obtained ionic flame retardant can be uniformly dispersed in a polymer, and after the ionic flame retardant is dissolved or dispersed in a high polymer material, the efficient flame retardant effect is achieved by utilizing the flame retardant property of the triazinyl compound amino phosphonate. The flame-retardant polypropylene disclosed by the invention takes the triazinyl compound as a flame retardant, so that the flame-retardant polypropylene not only has a small addition amount of the flame retardant, but also has good flame retardance.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardants, and specifically relates to an intumescent flame retardant and a preparation method and application thereof. Background Art

[0002] Intumescent flame retardants have shown great application prospects today when environmental problems are becoming increasingly severe due to their advantages such as high efficiency and environmental protection. At the same time, they have also attracted more and more researchers and flame retardant manufacturers to conduct extensive and in-depth research on the development and preparation of high-performance intumescent flame retardants. Since intumescent flame retardants are composed of three parts: acid source, carbon source and gas source, the reasonable combination of the "three sources" has always been the key to the development and preparation of high-performance intumescent flame retardants. Traditional intumescent flame retardants are obtained by mixing and compounding the three components of acid source, carbon source and gas source, usually composed of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL). The three components are often not evenly dispersed in the polymer matrix, so that the components cannot work well together, affecting their flame retardant efficiency. In addition, traditional intumescent flame retardants also have the problems of poor thermal stability and difficult processing.

[0003] At present, it is reported that ionic flame retardants can be evenly dispersed in polymers. Such flame retardants are also called "ionic solid flame retardants", which refer to molecules or ion groups composed of anions and cations. After being dissolved or dispersed in polymer materials, they can interact with polymer materials, thereby having the effect of preventing combustion. However, there are few types of ionic flame retardants in the prior art and their flame retardant efficiency is low, so it is necessary to develop ionic flame retardants with high flame retardant efficiency. Summary of the invention

[0004] In order to overcome the problems existing in the above prior art, one of the purposes of the present invention is to provide an intumescent flame retardant. Another purpose of the present invention is to provide a method for preparing the intumescent flame retardant. Another purpose of the present invention is to provide a flame retardant polyolefin.

[0005] Aminophosphonic acid compounds are a class of compounds containing both phosphorus and nitrogen, and are very suitable for use in intumescent flame retardants. However, in general, the phosphorus content of such compounds is much higher than the nitrogen content, which is not conducive to achieving high-performance flame retardancy due to the imbalance of phosphorus and nitrogen content. Triazine compounds are a class of compounds rich in tertiary nitrogen structures, which can be used as carbon sources and gas sources in intumescent flame retardants, and the nitrogen content of such compounds is relatively high. When combined with aminophosphonic acid compounds, an intumescent flame retardant with balanced phosphorus and nitrogen can be obtained. Therefore, the present application combines the structural and physical property advantages of aminophosphonic acid compounds and triazine compounds, combines aminophosphonic acid compounds with triazine compounds in the form of ionic bonds, and proposes a triazine-based compound used as a "three-source" integrated intumescent flame retardant.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A first aspect of the present invention provides an intumescent flame retardant, wherein the intumescent flame retardant is a compound formed by ionically bonding a triazine compound and an aminophosphonic acid.

[0008] Preferably, the molar ratio of the triazine compound to the aminophosphonic acid is (0.5-3):1.

[0009] More preferably, the molar ratio of the triazine compound to the aminophosphonic acid is (0.75-2):1.

[0010] Preferably, the aminophosphonic acid has a structural formula as shown in Formula 1 to Formula 6:

[0011]

[0012] Preferably, the structural formula of the triazine compound is as shown in formula a or formula b:

[0013]

[0014] Wherein, R1 and R2 are independently selected from one of amino, nitrogen-containing alicyclic group, nitrogen-containing aromatic heterocyclic group, alicyclic amino, arylamino, aliphatic amino; and X is an alkanediamine group.

[0015] Preferably, the triazine compound has a structural formula as shown in Formula 7 to Formula 10 below:

[0016]

[0017] The second aspect of the present invention provides a method for preparing the intumescent flame retardant of the first aspect, comprising the following steps: a triazine compound and aminophosphonic acid react in water to prepare the intumescent flame retardant.

[0018] Preferably, the reaction temperature is 70-100°C.

[0019] More preferably, the reaction temperature is 85 to 95°C.

[0020] Preferably, the reaction time is 3-7h.

[0021] More preferably, the reaction time is 3-5h.

[0022] Preferably, the mass ratio of water to aminophosphonic acid is (10-30):1.

[0023] More preferably, the mass ratio of water to aminophosphonic acid is (10-20):1.

[0024] The third aspect of the present invention provides a flame retardant polyolefin, comprising the intumescent flame retardant described in the first aspect.

[0025] Preferably, the mass percentage of the triazine-based compound in the flame retardant polypropylene is 15-25%.

[0026] More preferably, the mass percentage of the triazine-based compound in the flame retardant polypropylene is 20-23%.

[0027] Preferably, the flame retardant polyolefin comprises the following components: polyolefin, a lubricant, an antioxidant, a coupling agent and the triazine-based compound described in the first aspect.

[0028] Preferably, the flame retardant polyolefin is made of the following components in mass percentage: 75%-84% polyolefin, 0.3%-0.5% lubricant, 0.1%-0.3% antioxidant, 0.2%-0.4% coupling agent and 15-25% of the triazine compound described in the first aspect.

[0029] More preferably, the flame retardant polypropylene is prepared by a preparation method comprising the following steps: extruding and granulating the components to obtain the flame retardant polypropylene.

[0030] More preferably, the extrusion temperature is 170-195°C.

[0031] More preferably, the lubricant is a combination of an internal lubricant and an external lubricant.

[0032] More preferably, the coupling agent is a titanate coupling agent.

[0033] Preferably, the flame retardant polyolefin is flame retardant polypropylene.

[0034] The beneficial effects of the present invention are:

[0035] The present invention provides an intumescent flame retardant, which is a compound formed by ionically bonding a triazine compound and an aminophosphonic acid, wherein the aminophosphonic acid compound contains both phosphorus and nitrogen, and the triazine compound is a type of tertiary nitrogen-rich structure, so a "three-source" integrated intumescent flame retardant can be prepared by combining the characteristics of the two, and the triazine compound can balance the phosphorus and nitrogen of the flame retardant. The triazine-based compound of the present invention is bonded by ion bonds, and the obtained ionic flame retardant can be uniformly dispersed in a polymer, and after being dissolved or dispersed in a polymer material, the flame retardant performance of the aminophosphonic acid salt of the triazine compound is utilized to achieve a flame retardant and efficient effect.

[0036] Specifically, compared with the prior art, the present invention has the following advantages:

[0037] (1) The present invention also provides a method for preparing an intumescent flame retardant, wherein the intumescent flame retardant is prepared in a water reaction system without using an organic solvent. The preparation method has the characteristics of simple process and green environmental protection, and is convenient for industrial production.

[0038] (2) The present invention also provides a flame-retardant polyolefin. The three-source integrated intumescent flame retardant reported so far has a low flame retardant efficiency for polyolefin materials. To achieve the UL-94V-0 level in the vertical combustion test, the amount added must be above 25wt%. The flame-retardant polypropylene of the present invention uses a triazine-based compound as a flame retardant. Not only is the amount of flame retardant added small, but it also has good flame retardant properties. The flame retardant effect of UL-94V-0 can be achieved at a low addition amount of 21wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The infrared spectrum of the triazine compound 1 cyanurate flame retardant provided in Example 1;

[0040] Figure 2 The infrared spectrum of the triazine compound 2 cyanurate flame retardant provided in Example 2;

[0041] Figure 3 The infrared spectrum of the triazine compound 3 cyanurate flame retardant provided in Example 3;

[0042] Figure 4 This is the infrared spectrum of the triazine compound 4 cyanurate flame retardant provided in Example 4. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0044] Example 1

[0045] This embodiment provides an intumescent flame retardant, and the preparation method thereof is as follows:

[0046] Triazine compound 1 (55.6 g, 0.2 mol), aminotrimethylenephosphonic acid aqueous solution (concentration 50%, 119.6 g, 0.2 mol) and 1500 mL of water were placed in a 2 L round bottom flask, and then stirred at 90 ° C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, and then filtered, dried and crushed to obtain triazine compound 1 aminotrimethylenephosphonic acid salt, i.e., an intumescent flame retardant;

[0047] The structural formula of triazine compound 1 is:

[0048]

[0049] The structural formula of triazine compound 1 aminotrimethylene phosphonate is:

[0050]

[0051] The infrared spectrum of the triazine compound 1 aminotrimethylenephosphonate is shown in Figure 1 .

[0052] Example 2

[0053] This embodiment provides an intumescent flame retardant, and the preparation method thereof is as follows:

[0054] Triazine compound 2 (67.6 g, 0.2 mol), aminotrimethylenephosphonic acid aqueous solution (concentration 50%, 119.6 g, 0.2 mol) and 1500 mL of water were placed in a 2 L round bottom flask, and then stirred at 90 ° C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, and then filtered, dried and crushed to obtain triazine compound 2 aminotrimethylenephosphonate, i.e., an intumescent flame retardant;

[0055] The triazine compound 2 has the structural formula:

[0056]

[0057] The structural formula of triazine compound 2 aminotrimethylenephosphonate is:

[0058]

[0059] The infrared spectrum of the triazine compound 2-aminotrimethylenephosphonate is shown in Figure 2 .

[0060] Example 3

[0061] This embodiment provides an intumescent flame retardant, and the preparation method thereof is as follows:

[0062] The triazine compound 3 (38.8 g, 0.2 mol), aminotrimethylenephosphonic acid aqueous solution (concentration 50%, 119.6 g, 0.2 mol) and 1500 mL of water were placed in a 2 L round bottom flask, stirred and reacted at 90 ° C for 4 hours, cooled after the reaction, filtered, dried and crushed to obtain the triazine compound 3 aminotrimethylenephosphonate, i.e., an intumescent flame retardant;

[0063] The structural formula of the triazine compound 3 is:

[0064]

[0065] The structural formula of the triazine compound 3-aminotrimethylenephosphonate is:

[0066]

[0067] The infrared spectrum of the triazine compound 3-aminotrimethylenephosphonate is shown in Figure 3 .

[0068] Example 4

[0069] This embodiment provides an intumescent flame retardant, and the preparation method thereof is as follows:

[0070] Triazine compound 4 (58 g, 0.2 mol), aminotrimethylenephosphonic acid aqueous solution (concentration 50%, 119.6 g, 0.2 mol) and 1500 mL of water were placed in a 5 L round-bottom flask, stirred and reacted at 90 ° C for 4 hours, cooled after the reaction, filtered, dried and crushed to obtain triazine compound 4 aminotrimethylenephosphonate, i.e., an intumescent flame retardant;

[0071] The structural formula of the triazine compound 4 is:

[0072]

[0073] The structural formula of the triazine compound 4-aminotrimethylenephosphonate is:

[0074]

[0075] The infrared spectrum of triazine compound 4-aminotrimethylenephosphonate is shown in Figure 4 .

[0076] Experimental analysis

[0077] The flame retardant properties of the products of Examples 1-4 were tested, and the specific test methods and results are as follows:

[0078] Flame-retardant PP strips were prepared according to the formula in Table 1 below. Specifically, the raw materials were added to a mixer, the speed was set to 1000 rpm, and the mixture was stirred for 3 minutes. The mixed materials were then extruded using a co-rotating twin-screw extruder (Nanjing Keya) with an aspect ratio of 48:1 and a screw diameter of 36 mm. The extruder temperature was set to 170-195°C, the speed was 200 rpm, the vacuum degree was -0.8 MPa, and the pellets were cooled with water at 25±5°C and pelletized. The pellets were placed in a blast dryer, the temperature was set to 85°C, and the pellets were dried for 3 hours to prepare flame-retardant PP strips 1-4 corresponding to the flame retardants of Examples 1-4. The injection molding temperature was set to 180-195°C, and each particle was injection molded into a standard strip for UL 94 flame retardancy test. The test results are shown in Table 2.

[0079] Table 1 Raw material composition of flame retardant PP materials (parts by mass)

[0080]

[0081]

[0082] Table 2 Flame retardant properties test results of flame retardant PP materials

[0083]

[0084] From the test results of the flame retardant of Examples 1 to 4 in PP flame retardant application, it can be seen that the flame retardants of Examples 1 to 4 have good flame retardant properties. This is because the flame retardants of Examples 1 to 4 contain complete and balanced "three-source" components of the intumescent flame retardant in a single molecule, and thus have good flame retardant properties.

[0085] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An intumescent flame retardant, characterized in that: The intumescent flame retardant is a compound formed by ion bonding of a triazine compound and an aminophosphonic acid.

2. The intumescent flame retardant according to claim 1, characterized in that The molar ratio of the triazine compound to the aminophosphonic acid is (0.5-3):

1.

3. The intumescent flame retardant according to claim 1 or 2, characterized in that The structural formula of the aminophosphonic acid is shown in Formula 1-6:

4. The intumescent flame retardant according to claim 1 or 2, characterized in that The structural formula of the triazine compound is shown in formula a or formula b: Wherein, R1 and R2 are independently selected from one of amino, nitrogen-containing alicyclic group, nitrogen-containing aromatic heterocyclic group, alicyclic amino, arylamino, aliphatic amino; and X is an alkanediamine group.

5. The intumescent flame retardant according to claim 4, characterized in that The structural formula of the triazine compound is shown in Formula 7 to Formula 10:

6. The method for preparing the intumescent flame retardant according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: a triazine compound and aminophosphonic acid react in water to prepare the intumescent flame retardant.

7. The preparation method according to claim 6, characterized in that: The reaction temperature is 70-100° C.; and / or the reaction time is 3-7 hours.

8. The preparation method according to claim 6, characterized in that: The mass ratio of water to aminophosphonic acid is (10-30):

1.

9. A flame retardant polyolefin, characterized in that: The invention comprises the intumescent flame retardant according to any one of claims 1 to 5.

10. The flame retardant polyolefin according to claim 9, characterized in that: The flame retardant polyolefin further comprises the following components: polyolefin, lubricant, antioxidant and coupling agent.

Images