CONDENSATE OF POLY/MONO-PHOSPHOROUS ACID AND ALUMINUM HYDROGEN PHOSPHITE, PREPARATION AND APPLICATION THEREOF

Abstract

The present invention discloses a crystalline aluminum phosphite, preparation and an application thereof. The compound has the following structural formula (I):

##STR00001##

where, x is an integer of 1-6; n, y and p are an integer of 1-4; M is Ca, Mg, Al, Zn, Fe, Sn or Ti. The preparation method includes: after dissolving phosphorous acid and hydrogen phosphite into water, adding concentrated phosphoric acid for reaction at 80-90° C., then performing drying at low temperature, dehydration reaction at high temperature, washing and drying. The compound has very high thermal decomposition temperature, high phosphorus content, and good flame retardant property, low water absorption and low acidity; moreover, the compound can serve as a halogen-free flame retardant component of high polymer materials.

Claims

1. A condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite, characterized in that a structural formula of the condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite is shown as formula (I): ##STR00008## wherein, x is an integer of 1-6; n, y and p are an integer of 1-4; M is Ca, Mg, Al, Zn, Fe, Sn or Ti.

2. The condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite according to claim 1, characterized in that M is Al or Ca, and p is 1 or 2.

3. The condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite according to claim 1, characterized in that the condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite has a particle size of 0.1-1000 μm, a water solubility of 0.01-10 g/L, a bulk density of 80-800 g/L, and a water content not greater than 5 wt %.

4. A preparation method of the condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite according to claim 1, characterized by comprising the following steps: (1) dissolving phosphorous acid and a metal M of hydrogen phosphite, as a reactant, into water, then adding concentrated phosphoric acid being 1%-5% of the mass of the reactant and having a concentration not less than 85 wt %, and performing stirring evenly for reaction at 80-90° C., wherein M is Ca, Mg, Al, Zn, Fe, Sn or Ti; (2) drying the material obtained in the step (1) until a water content of the material falls below 0.3 wt %, wherein the drying temperature is controlled to be below 150° C.; (3) performing dehydration reaction on the dried product obtained in the step (2) in an inert atmosphere or under vacuum conditions at 200-300° C., and terminating the dehydration reaction when a temperature corresponding to a thermal weight loss of 2 wt % of the product is greater than 400° C., and performing cooling to room temperature and performing discharging to obtain a solid; (4) washing the solid obtained in the step (3) with water until washing effluent has a conductivity less than 50 μs/cm, drying the washed product until the product has a water content less than 0.3 wt %, thereby obtaining the condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite.

5. The preparation method according to claim 4, characterized in that in the step (1), a mass ratio of the reactant to the water is 20%-50%; and the reaction time is 2-3 h; and in the step (3), the dehydration reaction time is 1-10 h.

6. A method for the preparation of a flame retardant or a flame retardant synergist comprising the step of utilizing the condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite according to claim 1.

7. The method according to claim 6, characterized in that the flame retardant or the flame retardant synergist is used for the inflaming retarding of a varnish or a foaming coating, or is used for the inflaming retarding of timber or a cellulose-containing product, or is used for the preparation of a flame-retardant polymer molding material, flame-retardant polymer film, and a flame-retardant polymer fiber.

8. The method according to claim 7, characterized in that the flame-retardant polymer molding material, the flame-retardant polymer film, and the flame-retardant polymer fiber comprise the following ingredients based on 100% by total mass of the raw materials: 55%-99.9% of polymer matrix, 0.1%-45% of condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite, 0-44.9% of filler and/or reinforcing material, and 0-44.9% of other additives.

9. The method according to claim 7, characterized in that the flame-retardant polymer molding material, the flame-retardant polymer film, and the flame-retardant polymer fiber comprise the following ingredients based on 100% by total mass of the raw materials: 55%-99.9% of polymer matrix, 0.1%-45% of flame-retardant system, 0-44.9% of filler and/or reinforcing material, and 0-44.9% of other additives; based on 100% by total mass of the flame-retardant system, the flame-retardant system comprises: 0.1%-50% of condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite, and 50%-99.9% of flame retardant.

10. The method according to claim 8, characterized in that the polymer matrix is at least one of nylon, polyester and POK.

11. The method according to claim 9, wherein the polymer matrix is at least one of nylon, polyester and POK.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The present invention will be further set forth in combination with the specific embodiments below. It should be understood that these embodiments are only used to illustrate the present invention, but not for the limitation of the scope of the present invention. The operating method not noted with specific condition in the following examples is usually subjected to conventional conditions or the conditions recommended by a manufacturer.

Test items and methods:

[0056] 1. The prepared compound was subjected to elemental analysis to determine the ratio of each element and obtain a P content:

[0057] 2. Test on water absorption: 50 g materials were weighed and put in a constant temperature humidity chamber under conditions of 85% humidity at 85° C., kept for 7 d to test the weight increment of the material; and the percentage of the weight increment was, namely, the water absorption of the material;

[0058] 3. Test on the acidity of the prepared compound: 10 g powdered material was dispersed into 100 g water, and kept for 2 hr at a constant temperature of 25° C. to test a pH value of the solution.

Example 1 Preparation of a Condensate of Mono-Phosphorous acid and Aluminum Hydrogen Phosphite

[0059] The condensate of mono-phosphorous acid and aluminum hydrogen phosphite has the following structural formula (I):

##STR00006##

[0060] The preparation process was as follows: 82 g (1 mol) phosphorous acid, 540 g (2 mol) aluminum hydrogen phosphite ((H.sub.2PO.sub.3).sub.3Al) and 12 g concentrated phosphoric acid (H.sub.3PO.sub.4) having a concentration of 85.1 wt % were dissolved into 1500 g water, and fully stirred and mixed evenly for reaction for 3 h at 85° C., then subjected to rotary evaporation at −0.08 MPa and 85° C. until water content was 50 wt %. The materials were transferred to a drying oven and heated up to 130° C., and dried for 120 min; solids had a water content of 0.2 wt %; dried solids were put in a high-temperature vacuum oven, and heated for 3 h at 240° C., and cooled to room temperature and discharged; the materials were washed for separation until washing effluent had a conductivity less than 50 μs/cm, and dried at 130° C. until the water content was 0.08 wt %; then the materials were crushed; the mean grain size D50 was 40 μm, and yield was 97.8%; and the materials were subjected to relevant tests and application.

[0061] Table 1 shows an elemental analysis result of the condensate of mono-phosphorous acid and aluminum hydrogen phosphite

TABLE-US-00001 TABLE 1 Element Ratio (%) P 41.5 Al 8.0 O 50.5

[0062] The content of each element in Table 1 was very close to the theoretical calculating value, indicating that the prepared compound was the condensate of mono-phosphorous acid and aluminum hydrogen phosphite. Water absorption and pH value were shown in Table 3.

Example 2 Preparation of a Condensate of Di-Phosphorous Acid and Aluminum Hydrogen Phosphite

[0063] The condensate of di-phosphorous acid and aluminum hydrogen phosphite has the following structural formula:

##STR00007##

[0064] The preparation process was as follows: 164 g (2 mol) phosphorous acid, 540 g (2 mol) aluminum hydrogen phosphite ((H.sub.2PO.sub.3).sub.3Al) and 14 g concentrated phosphoric acid (H.sub.3PO.sub.4) having a concentration of 85.1 wt % were dissolved into 1600 g water, and fully stirred and mixed evenly for reaction for 3 h at 85° C., then subjected to rotary evaporation at −0.08 MPa and 85° C. until water content was 50 wt %. The materials were transferred to a drying oven and heated up to 130° C., and dried for 120 min; solids had a water content of 0.2 wt %; dried solids were put in a high-temperature vacuum oven, and heated for 3 h at 240° C., and cooled to room temperature and discharged; the materials were washed for separation until washing effluent had a conductivity less than 50 μs/cm, and dried at 130° C. until the water content was 0.08 wt %; then the materials were crushed; the mean grain size D50 was 42 μm, and yield was 86.5%; and the materials were subjected relevant tests and application.

[0065] Table 2 shows an elemental analysis result of the condensate of di-phosphorous acid and aluminum hydrogen phosphite.

TABLE-US-00002 TABLE 2 Element Ratio (wt %) P 43.4 Al 6.4 O 50.2

[0066] The content of each element in Table 2 was very close to the theoretical calculating value, indicating that the prepared compound was the condensate of di-phosphorous acid and aluminum hydrogen phosphite. Water absorption and pH value were shown in Table 3.

Comparative Example 1

[0067] The preparation process of the Comparative Example 1 was the same as that in Example 1 except solid reactants were not put in water for reaction, but directly mixed evenly, then put in a high temperature oven for dehydration to obtain materials, then the water absorption and pH value were tested, and results were shown in Table 3.

Comparative Example 2

[0068] The preparation process of the Comparative Example 2 was the same as that in Example 1 except 2 mol aluminum hydrogen phosphite was replaced with 2 mol phosphorous acid to prepare materials, then the water absorption and pH value were tested, and results were shown in Table 3.

Comparative Example 3

[0069] The preparation process of the Comparative Example 3 was the same as those in Example 1 except 1 mol phosphorous acid was replaced with 2 mol aluminum hydrogen phosphite to prepare materials, then the water absorption and pH value were tested, and results were shown in Table 3.

TABLE-US-00003 TABLE 3 P content Water absorption pH (wt %) (%) value Example 1 41.5 0.09 4.3 Example 2 43.4 0.07 4.5 Comparative 38.7 0.3 2.8 Example 1 Comparative 43.7 >10 <1 Example 2 Comparative 38.8 0.2 3.3 Example 3 Phosphorous acid 39.2 >10 <1 Aluminum hydrogen 35.2 >10 <1 phosphite Aluminum phosphite 32.0 0.5 2.6

[0070] It can be seen from the results of Table 3 that the compound of the present invention has a higher P content, lower water absorption and weaker acidity relative to phosphorous acid, aluminum hydrogen phosphite and aluminum phosphite; and these characteristics have obvious advantages for the compound as a flame retardant. Compared with the preparation process of the comparative examples, the preparation method provided by the present invention can obtain the target compound, indicating the effectiveness of the preparation method. In the preparation process, with the increase of phosphorous acid units; that is, x increases, P content will increase, water adsorption and acidity will decrease, but the yield will decrease; the number of phosphorous acid units is preferably, 1-2, capable of satisfying the application demands.

Application of a Flame Retardant

Example 3

[0071] 50 wt % nylon 66, 30 wt % glass fiber, 3.8 wt % condensate of mono-phosphorous acid and aluminum hydrogen phosphite in Example 1 and 16.2 wt % diethyl phosphinic aluminum (LFR8003, Jiangsu LiSiDe New Material Co., Ltd.) were prepared into a fire-retardant glass fiber reinforced nylon 66 by conventional regulations, and a sample was prepared to test the flame retardant property, and the flame retardant property of the material was up to UL94 VO (0.8 mm).

Example 4

[0072] 52 wt % nylon 66, 30 wt % glass fiber, 3 wt % condensate of di-phosphorous acid and aluminum hydrogen phosphite in Example 2 and 15 wt % diethyl phosphinic aluminum (LFR8003, Jiangsu LiSiDe New Material Co., Ltd.) were prepared into a fire-retardant glass fiber reinforced nylon 66 by conventional regulations, and a sample was prepared to test the flame retardant property, and the flame retardant property of the material was up to UL94 VO (0.8 mm).

Comparative Example 4

[0073] 50 wt % nylon 66, 30 wt % glass fiber, and 20 wt % diethyl phosphinic aluminum (LFR8003, Jiangsu LiSiDe New Material Co., Ltd.) were prepared into a fire-retardant glass fiber reinforced nylon 66 by conventional regulations, and a sample was prepared to test the flame retardant property, and the flame retardant property of the material was up to UL94 V2 (0.8 mm).(Based on the flame-retardant grading standard of UL94, the flame retardant efficiency of grade V2 was inferior to that of grade V0).

[0074] It can be seen from the application results that the condensate of poly/mono-phosphorous acid and aluminum hydrogen phosphite of the present invention may be synergistic to diethyl phosphinic aluminum to improve the flame retardant efficiency.

[0075] Moreover, it should be understood that a person skilled in the art may make various alterations or modifications to the present invention after reading the above description of the present invention, and these equivalent forms should fall within the scope of the claims of the present application.