ALUMINUM PHOSPHITE-BASED COMPLEX WITH DUAL-PEAK THERMAL GRAVITY DECOMPOSITION CHARACTERISTICS AND PREPARATION METHOD AND USE THEREOF

Abstract

The present disclosure provides an aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics and a preparation method and use thereof. A structural formula of the complex is as follows: ((HPO.sub.3).sub.3Al.sub.2).((H.sub.2PO.sub.3).sub.3Al).sub.x, wherein x is 0.01-0.5 and represents a molar ratio of (H.sub.2PO.sub.3).sub.3Al to (HPO.sub.3).sub.3Al.sub.2. The dual-peak thermal gravity decomposition characteristics are as follows: a first gravity peak temperature is 460-490° C., and a second gravity peak temperature is 550-580° C. The preparation method includes: uniformly mixing aluminum phosphite and aluminum hydrogen phosphite according to the ratio in the structural formula, and then performing stepwise heating at a rate of 5° C./min to raise the temperature of a mixture from the normal temperature to no more than 350° C. within 1-10 hours, so as to obtain the aluminum phosphite-based complex with the dual-peak thermal gravity decomposition characteristics. The complex may serve as or is configured to prepare a flame retardant or a flame-retardant synergist.

Claims

1. An aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics, a structural formula being as follows:
((HPO.sub.3).sub.3Al.sub.2).((H.sub.2PO.sub.3).sub.3Al).sub.x, wherein x is 0.01-0.5 and represents a molar ratio of (H.sub.2PO.sub.3).sub.3Al to (HPO.sub.3).sub.3Al.sub.2; and the dual-peak thermal gravity decomposition characteristics are as follows: a first gravity peak temperature is 460-490° C., and a second gravity peak temperature is 550-580° C.

2. The aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics according to claim 1, wherein pH is not lower than 3, a particle size is 0.1-1000 μm, the solubility in water is 0.01-10 g/L, the bulk density is 80-800 g/L, and the residual moisture is 0.1-5 wt %.

3. A preparation method of the aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics according to claim 1, comprising: uniformly mixing aluminum phosphite and aluminum hydrogen phosphite according to the ratio in the structural formula, and then performing stepwise heating at a rate of 5° C./min to raise the temperature of a mixture from the normal temperature to no more than 350° C. within 1-10 hours, so as to obtain the aluminum phosphite-based complex with the dual-peak thermal gravity decomposition characteristics.

4. The preparation method according to claim 3, wherein three heat preservation platforms, being 160° C., 220° C. and 280° C. respectively, are set during the stepwise heating, and heat preservation time is independently 30-60 min.

5. A method of using the aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics according to claim 1, wherein the complex serves as or is configured to prepare a flame retardant or a flame-retardant synergist, and is configured to: perform flame retarding of a varnish or a foam coating; perform flame retarding of wood or a cellulose-containing product; and prepare a flame-retardant polymeric molding material, a flame-retardant polymer film, and flame-retardant polymer fiber.

6. The method according to claim 5, wherein the flame-retardant polymeric molding material, the flame-retardant polymer film, and the flame-retardant polymer fiber, based on the total weight of 100%, each comprises: 55-99.9% of a polymer matrix, 0.1-45% of the aluminum phosphite-based complex with the dual-peak thermal gravity decomposition characteristics, 0-44.9% of a filler or a reinforcing material, and 0-44.9% of an additive.

7. The method according to claim 5, wherein the flame-retardant polymeric molding material, the flame-retardant polymer film, and the flame-retardant polymer fiber, based on the total weight of 100%, each comprises: 55-99.9% of a polymer matrix, 0.1-45% of a flame-retardant system, 0-44.9% of a filler or a reinforcing material, and 0-44.9% of an additive; and the flame-retardant system comprises 0.1-50% of the aluminum phosphite-based complex with the dual-peak thermal gravity decomposition characteristics, and 50-99.9% of a flame retardant.

8. The method according to claim 7, wherein the flame retardant is aluminum diethylphosphinate.

9. The method according to claim 6, wherein the polymer matrix is selected from at least one of polyamide, polyester, and polyketone (POK).

10. A preparation method of the aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics according to claim 2, comprising: uniformly mixing aluminum phosphite and aluminum hydrogen phosphite according to the ratio in the structural formula, and then performing stepwise heating at a rate of 5° C./min to raise the temperature of a mixture from the normal temperature to no more than 350° C. within 1-10 hours, so as to obtain the aluminum phosphite-based complex with the dual-peak thermal gravity decomposition characteristics.

11. A method of using the aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics according to claim 2, wherein the complex serves as or is configured to prepare a flame retardant or a flame-retardant synergist, and is configured to: perform flame retarding of a varnish or a foam coating; perform flame retarding of wood or a cellulose-containing product; and prepare a flame-retardant polymeric molding material, a flame-retardant polymer film, and flame-retardant polymer fiber.

12. The method according to claim 7, wherein the polymer matrix is selected from at least one of polyamide, polyester, and polyketone (POK).

13. The method according to claim 8, wherein the polymer matrix is selected from at least one of polyamide, polyester, and polyketone (POK).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a thermal gravity curve chart of aluminum phosphite;

[0045] FIG. 2 is a thermal gravity curve chart of aluminum hydrogen phosphite;

[0046] FIG. 3 is a thermal gravity curve chart of a simple mixture of the aluminum phosphite and the aluminum hydrogen phosphite; and

[0047] FIG. 4 is a thermal gravity curve chart of an aluminum phosphite-based complex with dual-peak thermal gravity decomposition characteristics prepared in an embodiment 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The present disclosure is further described below with reference to the accompanying drawings and specific examples. It should be understood that these examples are merely used to illustrate the present disclosure and not to limit the scope of the present disclosure. In the following examples, operation methods without specific conditions are usually in accordance with conventional conditions or conditions suggested by the manufacturer.

Example 1 Preparation of Aluminum Phosphite-Based Complex with Dual-Peak Thermal Gravity Decomposition Characteristics

[0049] A preparation method was as follows: 294 g (1 mol) of aluminum phosphite and 54 g (0.2 mol) of aluminum hydrogen phosphite were weighed respectively and mixed uniformly in a crucible. The crucible was put into an oven, the temperature was raised to 160° C. at a rate of 2° C./min and held for 30 min, the temperature was raised to 220° C. at a rate of 1° C./min and held for 60 min, the temperature was raised to 280° C. at a rate of 2° C./min and held for 60 min, the temperature was reduced to the room temperature, the materials were discharged and pulverized according to an average particle size D50 being 42 μm, and relevant testing and use were performed.

[0050] Testing Items and Methods:

[0051] (1) For the complex: a thermal gravity analysis (TGA) was tested, a heating rate was 20° C./min, and a nitrogen atmosphere was used. Through a differential curve (DTG) of TGA, a gravity peak temperature was obtained, and the complex of the present disclosure showed dual peaks on the curve of TGA, thereby achieving the objective of the present disclosure.

[0052] (2) Flame-retardant testing and use of the complex: testing was performed according to UL94 VO standards: five samples were tested, and each sample was ignited twice; the sample was ignited for 10 s each time and then left flames, and the sample was required to be extinguished within 10 s for which the sample left the flames; total after-flame time of the five samples ignited for ten times in total was not more than 50 s; it was stipulated that the sample was not combusted and did not drip during the ignition; and if the sample was not completely combusted, smoldering combustion without the flames for more than 30 s might not occur after ignition. On the premise that the total after-flame time satisfied the standard requirements, extinguishing time of secondary ignition of each sample was compared, and the shorter the extinguishing time of the secondary ignition was, the better the high-temperature flame-retardant protection effect of a flame retardant was.

[0053] (3) testing of a water absorption rate: certain materials were weighed and put into a constant temperature and humidity box of 85% humidity and 20° C. for 7 days (168 hours), and the materials were taken out and weighed, where increased weight was the weight of absorbed water, and the weight of the absorbed water was divided by the weight of the initial materials to obtain the water absorption rate.

[0054] (4) a pH testing method: 10 g of flame retardant powder was weighed and dispersed in 100 g of deionized water, stirring was performed at a constant temperature of 20° C. for 2 hours, the powder was filtered, and a pH value of a filtrate was measured with a pH meter.

[0055] FIG. 4 illustrated a TGA result of the dual-peak thermal gravity complex prepared in this example. The thermal gravity, the water absorption rate and the pH value were as shown in a table 1.

Comparative Example 1

[0056] It was the same as the example 1. Except that aluminum hydrogen phosphite was not used, other preparation processes were the same. Materials were obtained, and TGA was tested. A result was as shown in FIG. 1 and showed a single peak. A water absorption rate and a pH value were tested, and a result was as shown in a table 1.

Comparative Example 2

[0057] It was the same as the example 1. Except that aluminum hydrogen phosphite was not used, other preparation processes were the same. Materials were obtained, and TGA was tested. A result was as shown in FIG. 2 and showed a single peak. A water absorption rate and a pH value were tested, and a result was as shown in a table 1.

Comparative Example 3

[0058] It was the same as the example 1. Except that a molar ratio of aluminum hydrogen phosphite to aluminum phosphite was 1:0.6, other preparation processes were the same. Materials were obtained, and TGA was tested. A result showed dual peaks. A water absorption rate and a pH value were tested, and a result was as shown in a table 1.

Comparative Example 4

[0059] Aluminum phosphite and aluminum hydrogen phosphite were mixed according to a ratio in the example 1, high-temperature post-treatment was not performed, and TGA was directly tested. A result was as shown in FIG. 3 and showed dual peaks. A water absorption rate and a pH value were tested, and a result was as shown in a table 1.

TABLE-US-00001 TABLE 1 First peak Second peak Water temperature temperature absorption pH (° C.) (° C.) rate (%) value Example 1 474.9 567.5 0.18 3.1 Comparative 472.6 — 0.5 2.6 Example 1 Comparative 316.2 — >10 <1 Example 2 Comparative 322.7 472.1 >10 <1 Example 3 Comparative 328.3 472.9 >10 <1 Example 4

[0060] From the result in the Table 1, it may be seen that the prepared complex of the present disclosure has dual-peak thermal gravity characteristics, differing from single-peak thermal gravity characteristics of aluminum phosphite and aluminum hydrogen phosphite; and for a higher proportion of the aluminum hydrogen phosphite in mixing of the aluminum phosphite and the aluminum hydrogen phosphite as well as simple mixing of the aluminum phosphite and the aluminum hydrogen phosphite, the dual-peak thermal decomposition characteristics are also showed, but a superposition of thermal decomposition characteristic peaks of two kinds of mixtures is showed, and there are no high-temperature thermal decomposition peaks (namely, decomposition peaks of 550-580° C.). Compared with the samples in the comparative examples, the complex has different thermal decomposition characteristics as well as a higher thermal decomposition temperature, a lower water absorption rate and weaker acidity, indicating that the complex is one with a new structure; and meanwhile, these characteristics are obviously advantageous for use as a flame retardant.

[0061] Use of Flame Retardant

Example 2

[0062] 50 wt % of polyamide 66, 30 wt % of glass fiber, 4 wt % of a dual-peak thermal decomposition complex prepared according to the example 1 and 16 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Example 3

[0063] 52 wt % of polyamide 66, 30 wt % of glass fiber, 3.5 wt % of a dual-peak thermal decomposition complex prepared according to the example 1 and 14.5 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Comparative Example 5

[0064] 50 wt % of polyamide 66, 30 wt % of glass fiber and 20 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Comparative Example 6

[0065] 50 wt % of polyamide 66, 30 wt % of glass fiber, 4 wt % of a single-peak thermal decomposition sample prepared according to the comparative example 1 and 16 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Comparative Example 7

[0066] 50 wt % of polyamide 66, 30 wt % of glass fiber, 4 wt % of a single-peak thermal decomposition sample prepared according to the comparative example 2 and 16 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Comparative Example 8

[0067] 50 wt % of polyamide 66, 30 wt % of glass fiber, 4 wt % of a sample prepared according to the comparative example 3 and 16 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Comparative Example 9

[0068] 50 wt % of polyamide 66, 30 wt % of glass fiber, 4 wt % of a sample prepared according to the comparative example 4 and 16 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

Comparative Example 10

[0069] 52 wt % of polyamide 66, 30 wt % of glass fiber, 3.5 wt % of a sample prepared according to the comparative example 4 and 14.5 wt % of aluminum diethylphosphinate (LFR8003, Jiangsu Liside New Materials Co., Ltd.) were used to prepare flame-retardant glass fiber reinforced polyamide 66 according to general processes, and the flame-retardant properties were tested by sample preparation. A test result was as shown in a table 2.

TABLE-US-00002 TABLE 2 Detailed results of flame-retardant testing of different systems Example Example Comparative Comparative Comparative Comparative Comparative Comparative 2 3 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 t1(s) 15 23 122 13 10 14 12 21 t2(s) 12 19 140 26 34 28 30 36 t1 + t2 (s) 27 42 262 39 44 42 42 57 Whether to drip Not Not Not Not Not Not Not Not or not V0 PASS PASS FAIL PASS PASS PASS PASS FAIL flame-retardant evaluation

[0070] According to the use result, it may be seen that the dual-peak thermal decomposition complex of the present disclosure may cooperate with the aluminum diethylphosphinate to improve the flame-retardant effect, and may reduce the dosage of the flame retardant compared with the mixture. Meanwhile, compared with a single-component flame retardant of single-peak thermal decomposition and its simple mixture, during the cooperation with the aluminum diethylphosphinate, a flame-retardant grade of VO may be all achieved under the same dosage, but the dual-peak thermal decomposition complex of the present disclosure has shorter delayed combustion time (t1+t2), especially shorter delayed combustion time (t2) of second ignition, with a better flame-retardant effect, thereby reflecting the advantages of the dual-peak thermal decomposition complex.

[0071] In addition, it should be understood that those skilled in the art may make various variations or modifications to the present disclosure after reading the above description of the present disclosure, and these equivalent forms also fall within the scope limited by the appended claims of the present disclosure.