CN117247600A

CN117247600A - Porous dialkyl aluminum phosphinate particles and preparation method and application thereof

Info

Publication number: CN117247600A
Application number: CN202311331612.4A
Authority: CN
Inventors: 李金忠; 雷华; 王家凯
Original assignee: Jiangsu Liside New Materials Co ltd
Current assignee: Jiangsu Liside New Materials Co ltd
Priority date: 2023-10-16
Filing date: 2023-10-16
Publication date: 2023-12-19

Abstract

The invention discloses porous dialkyl aluminum phosphinate particles, and a preparation method and application thereof. In the preparation process of the porous aluminum dialkylphosphinate particles, aluminum dialkylphosphinate with asymmetric structures and different alkyl groups is used as seed crystals, so that the crystallization process is effectively regulated and controlled, porous aluminum dialkylphosphinate crystal particles with large inner apertures are obtained, feeding with large-particle-size particles can be realized, bridging is avoided, the problem of processing fluidity is solved, in-situ crushing and uniform dispersion can be realized, and the flame retardant property and mechanical property are improved. The porous aluminum dialkylphosphinate particles are used as or made into flame retardant, can improve the flame retardant property and mechanical property of halogen-free flame-retardant glass fiber reinforced engineering plastics, and are easy to prepare superfine powder, and belong to the field of new materials.

Description

Porous dialkyl aluminum phosphinate particles and preparation method and application thereof

Technical Field

The invention relates to the field of dialkylphosphinic acid aluminum, in particular to porous dialkylphosphinic acid aluminum particles, and a preparation method and application thereof.

Background

Glass fiber reinforced engineering plastics (such as various nylons, polyesters and the like) are widely applied to the fields of electronic appliances and the like due to the performance characteristics of good rigidity and impact resistance, low warpage, high heat resistance, good surface appearance and the like. In the application of these fields, flame retardant requirements are put on materials, and most of multi-process plastics are inflammable materials, and after being compounded with glass fibers, the glass fiber reinforced engineering plastics are easier to burn due to the wick effect of the glass fibers. Therefore, when the glass fiber reinforced engineering plastic is applied in the fields, the problem of flame retardance needs to be solved, and the flame retardance difficulty is higher due to the existence of a lampwick effect.

For flame retardance of glass fiber reinforced engineering plastics, two basic flame retardant systems are included: halogen-based flame retardant systems and non-halogen flame retardant systems. The halogen flame-retardant system is usually bromine-containing flame retardant and antimony trioxide, and a great deal of researches show that glass fiber reinforced engineering plastics added with the bromine flame retardant can generate harmful substances such as dense smoke, hydrogen bromide and the like during combustion, and can cause choking of human bodies. Therefore, the development of safe, environment-friendly and halogen-free flame retardant systems for glass fiber reinforced engineering plastics is a hot spot for research, and novel halogen-free flame retardants or flame retardant systems applied to glass fiber reinforced engineering plastics are developed in recent years.

Currently, the main stream of halogen-free flame retardants applied to glass fiber reinforced engineering plastics is a compound system based on dialkylphosphinate aluminum, which comprises the synergy of dialkylphosphinate aluminum and nitrogen-containing compounds, such as a dialkylphosphinate aluminum compound melamine polyphosphate (MPP) system and a nitrogen-free compound system of dialkylphosphinate aluminum and aluminum phosphite. These systems have high flame retardancy, high temperature resistance and no color trouble, and are widely used at present. However, the compound system based on the dialkyl aluminum phosphinate still has the problems of large addition amount and more decline of mechanical properties of materials. One of the important factors is that the aluminum dialkylphosphinate compound system is dispersed in a material matrix in the form of rigid particles, which can lead to the reduction of mechanical properties, and meanwhile, more flame retardant needs to be added to achieve a certain flame retardant standard, which can lead to more reduction of mechanical properties, and the effect of the particle size of the aluminum dialkylphosphinate flame retardant system, if the particle size is larger, can lead to the reduction of mechanical properties of the material. Therefore, to improve the mechanical properties of the glass fiber reinforced material to which the dialkylphosphinate flame retardant system is added, it is critical to achieve a finer particle size and uniform dispersion of the flame retardant system in the matrix material. And if the flame retardant is uniformly dispersed in a smaller particle size, the flame retardant property can be improved, the consumption of the flame retardant can be reduced, the addition of the flame retardant is reduced, and the mechanical property can be further improved. Although the particle size of the flame retardant system can be crushed into a smaller particle size by various crushing modes, two problems are faced in application, on one hand, the problem of fluidity exists, the problems of powder bridging, unsmooth discharging and the like are easily caused by fine particle size powder, and long-period operation is not easily realized; secondly, in a highly viscous polymer system, the particle size of the polymer is too fine to be agglomerated easily and to be dispersed uniformly. Thus, the processing flowability and dispersibility of the flame retardant system are in fact a pair of contradictions. In practical applications, to solve the problems of dispersibility and flowability, a flame retardant system with a larger particle size, such as an average particle size (D50) of more than 20 μm, is generally used, and a larger amount of flame retardant is actually required and certain mechanical properties of the material are sacrificed.

To this end, the solution that the inventors of the present application conceived is to use larger particle size flame retardant particles in order to avoid the problem of processing flowability, but to achieve that the flame retardant is dispersed in a material matrix with a finer particle size, it is possible to use the shearing action of the screw extruder during processing application of the particles of the flame retardant system to break the large particle size particles into a fine particle size in situ and achieve good dispersion? In the processing process, the retention time of the materials in the screw extruder is short, and the shearing force of the extruder is limited, so that in-situ crushing is realized, and the key is that the particles have the characteristic of easy crushing. The dialkyl phosphinate aluminum is an organic metal aluminum salt crystal, has higher hardness and is not easy to break. It is therefore easy to achieve that it is broken up if a large pore size can be formed inside the particles, so that it is easily broken up in situ into smaller particle size powder under the action of screw shear forces and a uniform dispersion is achieved. The present invention therefore proposes particles of dialkylphosphinic salts with a porosity, which solution has not been reported.

From the viewpoint of the preparation process of the aluminum dialkylphosphinate, the preparation of the aluminum dialkylphosphinate particles takes advantage of the low water solubility and crystallization characteristics of the aluminum dialkylphosphinate, and is obtained by crystallization precipitation in an aqueous phase through a metathesis reaction, and the actual granulation process is a crystallization process. The diethyl phosphinic acid aluminum particles are formed by stacking a large number of flaky small crystal grains with small size through electron microscopy, the sizes of the small crystal grains are very small, the crystal particles are relatively compact in a natural crystallization state, the internal pore diameter is small, the average pore diameter is smaller than 1nm as measured by a BJH method, and in-situ crushing is difficult to realize. Therefore, to obtain porous aluminum dialkylphosphinate particles having large pore diameters within the particles, it is critical to control the crystallization process during the aluminum dialkylphosphinate preparation. However, no report is made on how to realize the solution of large pore diameter inside the dialkylphosphinic acid aluminum particles.

Disclosure of Invention

The invention provides porous dialkyl aluminum phosphinate particles, and a preparation method and application thereof. Porous aluminum dialkylphosphinate particles are obtained by seeding with aluminum dialkylphosphinate having different alkyl groups with an asymmetric structure. In the preparation process of the porous aluminum dialkylphosphinate particles, aluminum dialkylphosphinate with different alkyl groups and an asymmetric structure is used as a seed crystal, so that the crystallization process can be effectively regulated and controlled, porous aluminum dialkylphosphinate crystal particles with large internal pore diameters can be obtained, feeding with particles with large particle diameters can be realized, bridging is avoided, the problem of processing fluidity is solved, in-situ crushing and uniform dispersion can be realized, and the flame retardant property and mechanical property are improved. The porous aluminum dialkylphosphinate particles are used as or made into flame retardant, can improve the flame retardant property and mechanical property of halogen-free flame-retardant glass fiber reinforced engineering plastics, and are easy to prepare superfine powder, and belong to the field of new materials.

A porous aluminum dialkylphosphinate particle having an average pore size of 1 to 1000nm as measured by the BJH method.

The porous aluminum dialkylphosphinate particles of the present invention may have an average particle size D50 of: 20 μm < D50<50 μm, bulk density can be 300-600g/L.

The porous aluminum dialkylphosphinate particles comprise one or more aluminum dialkylphosphinate particles having a molecular structure as shown in formula (I):

in the formula (I), R ₁ 、R ₂ Independently selected from alkyl groups with 2-6 carbon atoms;

and the porous aluminum dialkylphosphinate particles contain at least one aluminum dialkylphosphinate with different carbon number alkyl groups having a molecular structure as shown in the formula (II):

in the formula (II), R ₃ 、R ₄ Is alkyl with different carbon numbers and no less than 2.

That is, the porous aluminum dialkylphosphinate particles of the present invention must contain at least one type of aluminum dialkylphosphinate having an alkyl group of different carbon number having a molecular structure represented by the formula (II), and may not contain other aluminum dialkylphosphinate, but may contain any one or more other types of aluminum dialkylphosphinate having a molecular structure represented by the formula (I).

The porous dialkyl aluminum phosphinate particles have the characteristic of easy breakage, can be directly applied to glass fiber reinforced engineering plastics, become finer powder under the action of screw shearing force of a double screw extruder, promote the dispersion of the flame retardant in a material melt, and have higher flame retardant property and mechanical property. The superfine powder can also be prepared by various crushing modes and is applied to the field of ultrathin coatings.

The application aims at solving the contradiction that the existing halogen-free flame-retardant system based on the dialkylphosphinic acid aluminum widely applied to glass fiber reinforced engineering plastics is easy to bridge, unsmooth in blanking and the like due to the liquidity problem of dialkylphosphinic acid aluminum and the application of large particle size to cause large addition amount and the decline of mechanical properties of materials, and the inventor carries out extensive and intensive research.

According to research, in the crystallization preparation process of the aluminum dialkylphosphinate, the aluminum dialkylphosphinate with different alkyl groups is added, and the structural formula is shown as a formula (II), so that the aluminum dialkylphosphinate can play a role of seed crystals, influence the crystallization process, increase the internal pore diameter of crystal particles, obtain porous crystal particles, and ensure that the particle size of the particles is larger, and the generation of fine powder is reduced. More importantly, the porous crystalline particles have larger internal pore diameter and certain strength, are not easy to break into fine powder under the action of low shearing force during synthesis, but have larger internal pore diameter, the particle strength is lower than that of small pore diameter particles, and the inventor finds that the porous particles can be easily broken by a double-screw extruder with stronger shearing force in the processing and application process, so that the particles with small particle diameter are dispersed in polymer melt. The in-situ crushing and the smaller particle size distribution in the polymer body can improve the flame retardant efficiency and the mechanical property, and simultaneously can reduce the consumption of the flame retardant under the condition of meeting the same flame retardant standard, thereby further improving the mechanical property of the flame retardant material.

Further research shows that when the internal pore diameter of the porous dialkylphosphinic acid aluminum particles is measured by BJH method, the average pore diameter is 1-1000 nm, and the porous dialkylphosphinic acid aluminum particles have the characteristics that the particles have certain strength, but can be broken into smaller particles under the action of strong shearing force of a double-screw extruder. Too small pore diameter, the particles are not easy to break, and in-situ breaking into particles with smaller particle size can not be realized in the double-screw extruder; and too large pore size, too low strength, is easily broken during crystallization to form fine powder, which causes bridging problems during use.

In some cases, the porous aluminum dialkylphosphinate particles can further comprise at least one of the following components (a) - (C):

(A) Monoalkylphosphinates;

(B) Alkyl phosphonites;

(C) One or more of sulfate, chloride, phosphate, phosphite, hypophosphite, nitrate, acetate, nitrogen-containing compound, iron-containing compound, calcium-containing compound, magnesium-containing compound, titanium-containing compound, sodium-containing compound, and potassium-containing compound.

It has also been found that dialkylphosphinate particles have an internal pore size and R in formula (II) ₃ And R is ₄ Related to the difference in carbon number, R ₃ And R is ₄ The larger the difference in carbon number, the larger the internal pore size of the resulting particles. For example, the internal pore size of the particles prepared by using the aluminum ethyl butyl phosphinate as the seed crystal is smaller than that of the particles prepared by using the aluminum ethylhexyl phosphinate as the seed crystal.

In the present invention, R ₃ And R is ₄ The difference in carbon number of (2) or more is preferably not less than 2, and for example, the aluminum dialkylphosphinate having an alkyl group having a different carbon number as shown in the formula (II) is at least one of aluminum ethylbutylphosphinate and aluminum ethylhexyl phosphinate. The larger the difference in carbon number, the larger the internal pore size of the prepared particulate matter. While aluminum dialkylphosphinate having alkyl groups of the same carbon number can affect the crystallization process, the effect on the internal pore diameter of the particulate matter is small, and the object of the present invention cannot be achieved.

The invention also provides a preparation method of the porous aluminum dialkylphosphinate particles, which comprises the steps of uniformly dispersing aluminum dialkylphosphinate crystal seeds with different carbon number alkyl groups and with a molecular structure shown in a formula (II) and an average particle diameter D50 of more than 5 mu m and less than 50 mu m in a soluble aqueous solution of the dialkylphosphinate, adding water-soluble aluminum salt into the crystal seeds to react at 70-95 ℃, carrying out solid-liquid separation after the reaction, taking solid for washing, and drying to obtain the porous aluminum dialkylphosphinate particles.

In the preparation method of the invention, the average particle diameter D50 of the dialkylphosphinic acid aluminum seed crystal is more than 5 μm and less than 50 μm, preferably more than 20 μm and less than 40 μm. The research shows that the particle size of the dialkyl phosphinate aluminum seed crystal with different carbon numbers can influence the regulation effect on the internal pore diameter of the porous dialkyl phosphinate aluminum particles, and the particle size of the porous dialkyl phosphinate aluminum particles cannot be obviously regulated by the ultra-fine particle size and the ultra-coarse particle size, so that the aim of the invention can not be realized.

In the preparation method of the invention, the dialkyl phosphinate aluminum generated by the reaction of the soluble dialkyl phosphinate and the water-soluble aluminum salt can be the same as, not the same as or completely different from the dialkyl phosphinate aluminum seed crystal with different carbon number alkyl groups shown in the formula (II), and can be one or a mixture of more of diethyl phosphinate aluminum, ethyl butyl phosphinate aluminum, butyl phosphinate aluminum, ethylhexyl phosphinate aluminum, butyl hexyl phosphinate aluminum, hexyl phosphinate aluminum and the like.

In the invention, the mass percentage of the aluminum dialkylphosphinate seed crystal with different carbon number alkyl groups having the molecular structure shown in the formula (II) is 0.01 to 20 percent, preferably 0.1 to 5 percent, based on 100 percent of the mass of the aluminum dialkylphosphinate generated by the reaction of the soluble dialkylphosphinate and the water-soluble aluminum salt. The proper addition can effectively regulate and control the crystallization process, realize the regulation and control of the internal aperture of the particles and can not cause great change of the physical properties of the prepared aluminum dialkylphosphinate; the addition of excessive dialkylphosphinic aluminum with different carbon number alkyl groups does not further increase the internal pore diameter of the particles, and can obviously influence the physical properties of the prepared dialkylphosphinic aluminum, and the obtained physical properties of the obtained substance have large difference from those of pure dialkylphosphinic aluminum, which is not the purpose of the invention; too low an amount of addition, the regulation and control effect is limited, and the purpose of changing the internal aperture of the particulate matters is not achieved.

The soluble dialkylphosphinate salt can be at least one of sodium salt and potassium salt. The mass concentration of the soluble dialkylphosphinate in the soluble dialkylphosphinate aqueous solution may be 20 to 60 percent.

The soluble dialkylphosphinate aqueous solution can further comprise at least one of the following components (A) - (C):

(A) Monoalkylphosphinates;

(B) Alkyl phosphonites;

The small amount of the compounds does not influence the effect of dialkyl phosphinate aluminum with different alkyl groups on the internal pore diameter of the particles, and can still effectively improve the internal pore diameter of the particles. The presence of these compounds also allows the preparation of porous dialkylphosphinic aluminum containing these materials in relatively minor amounts.

In one embodiment, a pH regulator can be added into the reaction system before the reaction at 70-95 ℃. The pH regulator may include at least one of sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, and ammonia water. The addition amount of the pH regulator can be 0.01-5% of the mass of the porous dialkylphosphinic acid aluminum particles.

The water-soluble aluminum salt can be at least one of aluminum sulfate, aluminum nitrate and aluminum chloride.

In one embodiment, the water-soluble aluminum salt is added in an equimolar ratio to the soluble diethyl phosphinate salt. The mass concentration of the water-soluble aluminum salt compound in the reaction system is preferably 15-50%.

In the preparation method, the reaction can be finished by controlling the pH of a liquid phase to be less than 4 to obtain a solid precipitate; the control of the pH can be achieved by adding alkali or metal oxide or the like. The reaction time may be 1 to 5 hours.

The end point of the wash is preferably that the conductivity of the wash water is less than 500 mus/cm.

The drying can be performed by using various ovens, drying rooms, dryers, etc., and the drying temperature can be 100-130 ℃. The drying treatment may be performed under an inert atmosphere (nitrogen atmosphere, rare gas atmosphere, etc.) or under vacuum.

The invention also provides application of the porous aluminum dialkylphosphinate particles as a flame retardant in preparing flame retardant materials. In one embodiment, the porous aluminum dialkylphosphinate particles have an average particle size D50 of greater than 20 μm and less than 50 μm.

The matrix of the flame retardant material can be polyurethane, epoxy resin, thermosetting unsaturated polyester, nylon, thermoplastic polyester or engineering plastic POK, and the like, and further, glass fiber reinforcement, namely glass fiber reinforced flame retardant material, can be introduced.

The porous aluminum dialkylphosphinate particles prepared by the invention can be processed into superfine powder with a particle size, such as superfine powder with an average particle size D50 of 1 μm < D50<10 μm, through various crushing modes, such as mechanical crushing, jet milling and the like, and can be used as flame retardants in various ultrathin coating and laminating materials.

The invention also provides the use of the porous aluminum dialkylphosphinate particles as flame retardants for the preparation of coating, laminating materials after comminution into powders having an average particle diameter D50 of less than 20 μm, for example 1 μm < D50<10 μm.

The porous aluminum dialkylphosphinate of the present invention can be used as a flame retardant or a flame retardant synergist, and is used for the purposes of:

flame retardant of varnish or foaming paint;

flame retardant of wood or cellulose-containing products;

preparing a flame retardant polymer molding material, a flame retardant polymer film and flame retardant polymer fibers.

The flame-retardant polymer molding material, the flame-retardant polymer film and the flame-retardant polymer fiber comprise the following raw materials in percentage by mass:

the flame-retardant system comprises the following components in percentage by mass:

1 to 100 percent of porous dialkyl phosphinate aluminum

0 to 99 percent of other flame retardant synergist

The polymer matrix may be selected from PU (polyurethane), TPE (thermoplastic elastomer), epoxy, thermosetting unsaturated polyester, nylon, thermoplastic polyester, poi (polyketone).

In the flame retardant system, the other flame retardant and the flame retardant synergist can be selected from the following components:

dialkylphosphinic acids and/or salts thereof; a condensation product of melamine and/or a reaction product of melamine with phosphoric acid and/or a reaction product of a condensation product of melamine with polyphosphoric acid or a mixture thereof; nitrogen-containing phosphates; benzoguanamine, tris (hydroxyethyl) isocyanurate, allantoin, glycoluril, melamine cyanurate, dicyandiamide, and/or guanidine; magnesium oxide, calcium oxide, aluminum oxide, zinc oxide, manganese oxide, tin oxide, aluminum hydroxide, boehmite, hydrotalcite, hydrocalumite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, tin oxide hydrate, manganese hydroxide, zinc borate, basic zinc silicate, and/or zinc stannate; phosphite, hydrogen phosphite or condensates thereof; phosphate and derivatives thereof;

melam, melem, dimelamine pyrophosphate, melamine polyphosphate, melam polyphosphate, melem polyphosphate and/or mixed polybalts thereof and/or as ammonium hydrogen phosphate, monoammonium phosphate and/or ammonium polyphosphate;

aluminum hypophosphite, zinc hypophosphite, calcium hypophosphite, sodium phosphite, monophenyl phosphinic acid and salts thereof, mixtures of dialkyl phosphinic acid and salts thereof with monoalkyl phosphinic acid and salts thereof, 2-carboxyethyl alkyl phosphinic acid and salts thereof, 2-carboxyethyl methyl phosphinic acid and salts thereof, 2-carboxyethyl aryl phosphinic acid and salts thereof, 2-carboxyethyl phenyl phosphinic acid and salts thereof, DOPO and salts thereof, and adducts on p-benzoquinone.

The porous dialkylphosphinic aluminum particles have the characteristic of being easy to break into finer particle sizes. The flame retardant can be directly applied to glass fiber reinforced engineering plastics, becomes finer powder under the action of the shearing force of the screws of the double-screw extruder, promotes the dispersion of the flame retardant in the melt of the material, and has higher flame retardant property and mechanical property. The superfine powder can also be prepared by various crushing modes and is applied to the field of ultrathin coatings.

Compared with the prior art, the invention has the beneficial effects that:

the invention overcomes the defects of the prior dialkyl aluminum phosphinate, and the prepared porous dialkyl aluminum phosphinate has the characteristics of large internal pore diameter, easy breakage, low fine powder content, solves the fluidity problems of easy bridging, unsmooth blanking and the like, can realize in-situ breakage of particles in an extruder, promotes the dispersion of the flame retardant, reduces the consumption of the flame retardant, and improves the mechanical property of the material.

Detailed Description

The invention will be further illustrated with reference to specific examples. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention.

Example 1

The preparation process comprises the following steps: 144g (1 mol) of sodium diethylphosphinate was dissolved in 336g of water in a 2L reaction vessel, and the solution was sufficiently stirred and dissolved to obtain a sodium diethylphosphinate solution. 2.6g (2 wt%) of aluminum ethylbutylphosphinate (d50=25 μm) was added and stirred well to disperse the aluminum ethylbutylphosphinate uniformly in the solution. 57g of aluminum sulfate was dissolved in 133g of water in a 500mL beaker, 3.0g of 98wt% concentrated sulfuric acid was added to the aluminum sulfate solution, and the mixture was stirred well and transferred to a dropping funnel. The reaction kettle is heated, the temperature is raised to 90 ℃, the aluminum sulfate solution containing sulfuric acid is dripped, the dripping is completed for 2 hours, and the reaction is continued for 1 hour after the heat preservation. Filtering while the precipitate is hot, washing the precipitate for a plurality of times until the conductivity of the washing water is less than 200 mu s/cm, and stopping washing. Transferring the materials to an oven, heating to 120 ℃, drying for 60min, wherein the moisture content of the solid is 0.1wt%, cooling to normal temperature, discharging to obtain porous aluminum dialkylphosphinate particles, and testing the internal pore diameter of the particles, wherein the results are shown in Table 1.

Particle internal pore size test: BJH adsorption method.

Example 2

The procedure is as in example 1, except that the amount of aluminum ethylbutylphosphinate added is 5.2g (4 wt%) and the other conditions are unchanged. The results are shown in Table 1.

Example 3

The procedure was carried out in the same manner as in example 1, except that the average particle diameter of the added aluminum ethylbutylphosphinate was 35. Mu.m, and the other conditions were unchanged. The results are shown in Table 1.

Example 4

The procedure was carried out in the same manner as in example 1, except that the same mass of aluminum ethylhexyl phosphinate (d50=25 μm) was added, and the other conditions were unchanged. The results are shown in Table 1.

Comparative example 1

The procedure was as in example 1, except that aluminum ethylbutylphosphinate was not added, and the conditions were unchanged. The results are shown in Table 1.

Comparative example 2

The procedure was as in example 1, except that the seed aluminum ethylbutylphosphinate was changed to aluminum diethylphosphinate, and the conditions were unchanged. The results are shown in Table 1.

Comparative example 3

The procedure was carried out in the same manner as in example 1, except that the average particle diameter of the added aluminum ethylbutylphosphinate was 3. Mu.m, and the other conditions were unchanged. The results are shown in Table 1.

Comparative example 4

The procedure is as in example 1, with the addition of 0.01g of aluminum ethylbutylphosphinate, the other conditions being unchanged. The results are shown in Table 1.

TABLE 1

	Average pore diameter (nm) inside particles
		Example 1	4.2
Example 2	5.7
		Example 3	4.8
Example 4	6.2
		Comparative example 1	0.2
Comparative example 2	0.2
		Comparative example 3	0.3
Comparative example 4	0.2

From the results, the internal pore size of the particles prepared by using the dialkylphosphinic acid aluminum with different alkyl groups as seed crystals is larger.

Application of dialkyl phosphinate aluminum particles

Example 5

Flame retardant glass fiber reinforced PPA was prepared according to the general procedure using 55% wt high temperature nylon PPA,30% wt glass fiber, 15% wt aluminum dialkylphosphinate particles prepared according to example 1, and tested for flame retardant and mechanical properties. Results: the flame retardant of the material reaches UL 94V 0 (0.8 mm), and the impact strength is 125J/m.

Comparative example 5

The flame retardant glass fiber reinforced PPA was prepared according to the general procedure using 55% by weight of high temperature nylon PPA,30% by weight of glass fiber, 15% by weight of the aluminum dialkylphosphinate particles prepared according to comparative example 1, and tested for flame retardant and mechanical properties by sample preparation. Results: the flame retardant of the material reaches UL 94V 2 (0.8 mm), and the impact strength is 110J/m.

Comparative example 6

Flame retardant glass fiber reinforced PPA was prepared according to the general procedure using 52% wt of high temperature nylon PPA,30% wt of glass fiber, 18% wt of the aluminum dialkylphosphinate particles prepared according to comparative example 1, and tested for flame retardant properties by sample preparation. Results: the flame retardant of the material reaches UL 94V 0 (0.8 mm), and the impact strength is 95J/m.

The results show that the porous diethyl aluminum phosphinate prepared by the method can reduce the consumption of the flame retardant and improve the mechanical property of the material.

Further, it will be understood that various changes and modifications may be made by those skilled in the art after reading the foregoing description of the invention, and such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. The porous aluminum dialkylphosphinate particles are characterized in that the average pore diameter of the porous aluminum dialkylphosphinate particles is 1-1000 nm as measured by a BJH method;

2. The porous aluminum dialkylphosphinate particles of claim 1, further comprising at least one of the following components (a) - (C):

(A) Monoalkylphosphinates;

(B) Alkyl phosphonites;

3. The porous aluminum dialkylphosphinate particles of claim 1, wherein R ₃ And R is ₄ The difference of carbon numbers is not less than 2, for example, the dialkyl aluminum phosphinate with the alkyl groups with different carbon numbers and having the molecular structure shown in the formula (II) is at least one of ethyl butyl aluminum phosphinate and ethylhexyl aluminum phosphinate.

4. The method for producing porous aluminum dialkylphosphinate particles according to any one of claims 1 to 3, wherein the porous aluminum dialkylphosphinate particles are obtained by uniformly dispersing aluminum dialkylphosphinate seed crystals having different carbon number alkyl groups and having a molecular structure represented by the formula (II) in an aqueous solution of a soluble dialkylphosphinate, wherein the average particle diameter D50 is more than 5 μm and less than 50 μm (preferably more than 20 μm and less than 40 μm), adding a water-soluble aluminum salt thereto, reacting at 70 to 95℃and separating solid from liquid after the reaction, washing the solid and drying the solid after the reaction.

5. The process according to claim 4, wherein the mass percentage of the seed crystals of the aluminum dialkylphosphinate having the molecular structure represented by the formula (II) and having different alkyl groups of carbon number is 0.01 to 20%, preferably 0.1 to 5%, based on 100% by mass of the aluminum dialkylphosphinate produced by the reaction of the soluble dialkylphosphinate with the water-soluble aluminum salt.

6. The preparation method according to claim 4, wherein a pH regulator is further added into the reaction system before the reaction at 70-95 ℃, wherein the pH regulator comprises at least one of sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, sodium hydroxide, potassium hydroxide and ammonia water, and the addition amount of the pH regulator is 0.01-5% of the amount of the porous aluminum dialkylphosphinate particles.

7. The method according to claim 4, wherein the water-soluble aluminum salt is at least one of aluminum sulfate, aluminum nitrate, and aluminum chloride.

8. Use of porous aluminum dialkylphosphinate particles according to any one of claims 1 to 3 as flame retardant for the preparation of flame retardant materials.

9. The use according to claim 8, characterized in that the porous aluminium dialkylphosphinate particles have an average particle diameter D50 of more than 20 μm and less than 50 μm.

10. Use of porous aluminum dialkylphosphinate particles according to any of the claims 1 to 3 as flame retardant for the preparation of coating, laminating materials after comminution into powder, characterized in that the average particle size D50 of the powder is less than 20 μm, such as 1 μm < D50<10 μm.