CN103073751B - Expansion type flame retardant, flame retardant compositions containing this fire retardant, and fiber-reinforced polymer-matrix flame-proof composite material - Google Patents

Abstract

The present invention relates to a kind of expansion type flame retardant, flame retardant compositions containing this fire retardant, and the fiber-reinforced polymer-matrix flame-proof composite material utilizing this flame retardant compositions obtained.This expansion type flame retardant comprises: carbon source; Acid source; Source of the gas; And oxidation inhibitor, it comprises two (octadecyl) pentaerythritol diphosphites and/or hexadecyl pentaerythritol diphosphites.Matrix material comprises flame-proofed polymer material body and is arranged in the continuous fibre of described body, described flame-proofed polymer material body is integrated with continuous fibre, described flame-proofed polymer material body obtains by making the solidification of the flame retardant compositions containing this fire retardant, the fiber-reinforced polymer-matrix flame-proof composite material that the present invention prepares, after being burnt, still possesses excellent thermomechanical property.

Description

Intumescent flame retardant, flame retardant polymer composition containing same, and fiber-reinforced polymer-based flame retardant composite

technical field

The invention belongs to the field of intumescent flame retardants and fiber-reinforced polymer-based composite materials, and in particular relates to a quaternary intumescent flame retardant, a flame-retardant polymer composition containing the flame retardant, and a compound prepared by using the composition Continuous fiber reinforced polymer based flame retardant composites.

Background technique

Fiber-reinforced polymer-based composites are widely used in aviation due to their high specific strength, high specific modulus, strong designability, good fatigue resistance, and ease of large-area integral molding at low temperatures (when the temperature is lower than 100°C). Aerospace, national defense, ships and transportation and other fields have been widely used. Because the matrix material of the polymer matrix composite material - the polymer softens and melts at a temperature higher than the glass transition temperature, and the molecular chain depolymerizes and thermally decomposes at a temperature higher than 300°C. After the fire, the polymer The matrix material of the matrix composite material becomes residue, the matrix loses the ability to bind the fiber reinforcement, and the load-bearing capacity of the structure is severely weakened. At the same time, dense smoke and toxic gases are likely to be produced during high-temperature flaming combustion, which is not conducive to people's escape, and its application in structural engineering with fire hazards is limited.

Methods to improve the fire performance of polymer-based composites include structural fire protection and material fire protection. In terms of structural fire protection, a layer of thermal insulation material can be sandwiched between the two-layer composite structure to achieve the purpose of fire resistance. In terms of material fire protection, a feasible method is to introduce flame retardant groups into polymer materials through chemical reactions, thereby improving the flame resistance of materials, preventing materials from being ignited and inhibiting the spread of flames. This reactive flame retardant The agent accounts for about 15% of the flame retardant. The usual flame retardant is an additive flame retardant, accounting for about 85% of the flame retardant, that is, the flame retardant is added to the polymer matrix of the composite material. Flame retardants exert their flame retardant effect through one or several mechanisms, such as absorbing heat, generating high-density non-combustible gas to dilute oxygen or combustible gas, forming a non-combustible protective film, improving the thermal stability of polymers, Capturing free radicals and inhibiting chain reactions can effectively prevent, delay or terminate the spread of flames, and improve the thermal properties of polymer-based composites under fire conditions.

In order to achieve better fire resistance of polymer-based composites, it is usually necessary to add flame-retardant additives at a content of 5-40% by weight of the polymer matrix, which will reduce the thermodynamic properties of polymer-based composites. In the published patents (CN102532693A; CN102532681A; CN102295792A), the addition of a large amount of flame retardants will lead to a significant decrease in the mechanical properties of composite materials, and there are relatively few reports on flame-retardant composite materials with excellent thermodynamic properties.

Therefore, it is one of the current challenges to solve the problem of the thermodynamic performance of polymer-based composites being reduced due to the addition of flame retardants, and to prepare environmentally friendly polymer-based flame-retardant composites with excellent thermodynamic properties. Carrying out the above research is of great value in preventing and reducing fires that may occur during the use of polymer matrix composite structures, increasing the escape time of personnel, and reducing the loss of life and property caused by fires.

Contents of the invention

The purpose of the present invention is to provide a fiber-reinforced polymer-based composite material with excellent thermodynamic properties, so the first aspect of the present invention first provides an intumescent flame retardant, which includes:

The carbon source is an organic compound with multiple hydroxyl groups;

Acid sources, which are inorganic acids or compounds capable of generating acids in situ upon combustion;

A source of gas, which is a nitrogen-containing compound capable of producing nitrogen gas upon combustion; and

Antioxidants include bis(octadecyl)pentaerythritol diphosphite (distearylpentaerythritoldisphosphite) and/or cetylpentaerythritoldiphosphite (cetylpentaerythritoldiphosphite).

In the present invention, the term "carbon source" is also called a char-forming agent, which is used to form a carbonized foam layer when fired. In another preferred example, the organic compound with multiple hydroxyl groups includes one or more of cellulose fiber (cellulose fiber), glucose, starch, sucrose, dextrin, pentaerythritol (pentaerythritol), ethylene glycol, and phenolic resin .

In the present invention, the term "acid source" is also called dehydrating agent or carbonization accelerator. In another preferred embodiment, the inorganic acid or the compound capable of generating acid in situ during combustion includes one or two or more of polysilicic acid, phosphoric acid, boric acid, sulfuric acid, phosphoric acid ester, and ammonium phosphate.

In the present invention, the term "air source" is also called a foaming source. In another preferred example, the nitrogen-containing compound includes one or two or more of urea, melamine, and polyamide.

In the present invention, the term "antioxidant" is used to block, inhibit or delay polymer oxidation or auto-oxidation process, including free radical inhibitors (free radical scavengers) or peroxide decomposing agents.

In another preferred example, the antioxidant is bis(octadecyl)pentaerythritol diphosphite.

In another preferred example, in the flame retardant, by weight, the ratio of the sum of the content of the carbon source and the acid source to the sum of the content of the gas source and the antioxidant is 1:3 to 3:1 .

In another preferred example, the content ratio of the carbon source to the acid source is 2:8 to 8:2.

In another preferred example, the content ratio of the gas source to the antioxidant is 1:2 to 2:1.

The second aspect of the present invention provides a kind of flame retardant polymer composition, it comprises:

As the aforementioned flame retardant of the present invention; and

A polymer precursor that forms a polymer material when cured by heat.

In the present invention, the term "composition" covers both the mixed and unmixed forms of the ingredients.

In another preferred example, the polymer precursor includes an epoxy resin containing 1,4-butanediol diglycidyl ether and an alicyclic amine-modified hardener.

In another preferred example, the polymer material includes one or more of epoxy resin, nylon, polyolefin, and polycarbonate.

The third aspect of the present invention is to provide a fiber-reinforced polymer-based flame-retardant composite material, which is characterized in that the composite material includes a flame-retardant polymer material body and continuous fibers located in the body, and the flame-retardant polymer The material body is integrated with the continuous fiber, and the flame retardant polymer material body is obtained by curing the flame retardant polymer composition of the present invention as described above.

In another preferred example, the composite material has the following thermodynamic properties: after the composite material is irradiated with a thermal radiation flux of 25kW/ ^m2 for 540 seconds and then tested according to the ASTM7264-07 test method, the initial temperature of the irradiated composite material is The stiffness is 0.205 to 0.225KN/mm, and the three-point bending strength is 370 to 403MPa.

In the present invention, the term "continuous fiber" refers to a fiber that is continuous without interruption.

In another preferred example, the continuous fibers are selected from one or more of glass fibers, carbon fibers, and aramid fibers.

In another preferred embodiment, the continuous fiber is in the form of fabric.

In another preferred example, based on the total weight of the composite material, the total content of the carbon source and the acid source accounts for 2.5wt% to 7.5wt% of the composite material.

In another preferred example, based on the total weight of the composite material, the total content of the gas source and the antioxidant is 2.5wt% to 7.5wt% of the composite material.

In another preferred example, based on the total weight of the composite material, the content of the continuous fiber accounts for 40wt% to 60wt% of the composite material.

In another preferred example, based on the total weight of the composite material, the content of the polymer material body is 35wt% to 45wt% of the composite material.

It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (such as embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, we will not repeat them here.

Description of drawings

Fig. 1 illustrates the mass loss curve obtained by thermogravimetric analysis of Example 1 of the present invention and Comparative Example 3;

Fig. 2 is the photograph illustrating the composite material plate that embodiment 1 makes after the thermal radiation experiment;

FIG. 3 is a photo illustrating the composite material plate prepared in Comparative Example 3 after the heat radiation experiment.

Detailed ways

After extensive and in-depth research, the inventors found that the fiber-reinforced polymer matrix prepared by using a flame retardant (hereinafter referred to as a quaternary flame retardant) containing a carbon source, an acid source, a gas source and an antioxidant at the same time Composite products have excellent thermodynamic properties, especially after burning, they can maintain the required stiffness and strength. Further, if [the sum of the content of carbon source and acid source] and [the sum of content of gas source and antioxidant] are two The ratio of the latter is controlled within a specific range, and the composite material will have excellent thermodynamic properties. The present invention has been accomplished on this basis.

Intumescent flame retardant and its preparation

Intumescent flame retardant of the present invention comprises:

The carbon source is an organic compound with multiple hydroxyl groups;

Acid sources, which are inorganic acids or compounds capable of generating acids in situ upon combustion;

A source of gas, which is a nitrogen-containing compound capable of producing nitrogen gas upon combustion; and

Antioxidants, including bis(octadecyl)pentaerythritol diphosphite and/or cetylpentaerythritol diphosphite.

Preferably, the organic compound with multiple hydroxyl groups includes one or two or more of cellulose fibers, glucose, starch, sucrose, dextrin, pentaerythritol, ethylene glycol, and phenolic resin.

Preferably, the inorganic acid or the compound capable of generating acid in situ during combustion includes one or more of polysilicic acid, phosphoric acid, boric acid, sulfuric acid, phosphoric acid ester, and ammonium phosphate.

Preferably, the nitrogen-containing compound contains one or two or more of urea, melamine and polyamide.

Preferably, the antioxidant is bis(octadecyl)pentaerythritol diphosphite.

Preferably, in the flame retardant, the ratio of the sum of the carbon source and the acid source to the sum of the gas source and the antioxidant is 1:3 to 3:1 by weight.

Preferably, the content ratio of carbon source to acid source is 2:8 to 8:2.

Preferably, the ratio of gas source to antioxidant is 1:2 to 2:1.

With regard to the preparation of the intumescent flame retardant of the present invention, it can be achieved by known means, for example simply mixing the four components. Or it can be prepared by first mixing carbon source and acid source into a composition (for example, commercially available VISIL) and gas source and antioxidant to form a composition, and then mixing the two compositions.

Flame retardant polymer composition and its preparation

The flame retardant polymer composition of the present invention comprises:

As the aforementioned flame retardant of the present invention; and

A polymer precursor that forms a polymer material when cured by heat.

Preferably, the polymer precursor includes an epoxy resin containing 1,4-butanediol diglycidyl ether and a cycloaliphatic amine-modified hardener.

Preferably, the polymer material contains one or more of epoxy resin, nylon, polyolefin, and polycarbonate.

The preparation of the flame retardant polymer composition of the present invention can be achieved by a known method, such as simply mixing the polymer precursor and the intumescent flame retardant at room temperature by mechanical stirring.

Fiber-reinforced polymer-based flame-retardant composites and their preparation

The fiber-reinforced polymer-based flame-retardant composite material of the present invention includes:

a body of flame retardant polymer material; and

The continuous fibers located in the body, the flame-retardant polymer material body is integrated with the continuous fibers, and the flame-retardant polymer material body is obtained by curing the flame-retardant polymer composition of the present invention as described above .

In another preferred example, the composite material has the following thermodynamic properties: after the composite material is irradiated with a thermal radiation flux of 25kW/ ^m2 for 540 seconds and then tested according to the ASTM7264-07 test method, the initial temperature of the irradiated composite material is The stiffness is 0.205 to 0.225KN/mm, and the three-point bending strength is 370 to 403MPa.

In the present invention, the term "continuous fiber" refers to a fiber that is continuous without interruption.

Preferably, the continuous fibers are selected from one or more of glass fibers, carbon fibers, and aramid fibers.

Preferably, the continuous fibers are in the form of fabrics.

Preferably, based on the total weight of the composite material, the sum of the content of the carbon source and the acid source accounts for 2.5wt% to 7.5wt% of the composite material.

Preferably, based on the total weight of the composite material, the total content of the gas source and the antioxidant is 2.5wt% to 7.5wt% of the composite material.

Preferably, based on the total weight of the composite material, the content of the continuous fiber accounts for 40wt% to 60wt% of the composite material.

Preferably, based on the total weight of the composite material, the content of the polymer material body is 35wt% to 45wt% of the composite material.

The preparation of the fiber-reinforced polymer-based flame-retardant composite material of the present invention can be carried out by conventional resin transfer molding (RTM) technology. A representative process includes steps: mold cleaning→coating hole sealing agent→coating release agent→installing sealing ring→loading preform containing continuous fiber into the mold→mold clamping and fastening→connecting vacuum pipeline and injecting Glue pipeline→vacuum leak detection→preheating mold and glue storage tank→glue compounding (configuration of the flame-retardant polymer composition of the present invention)→defoaming→pressurization→injecting glue (flame-retardant polymer composition) into the mold→ Solidification → cooling → demoulding → trimming.

Preferably, both the intumescent flame retardant and the flame-retardant composite material of the present invention do not contain halogen elements, and will not release toxic gases such as carbon monoxide or corrosive gases such as hydrogen halide when heated and decomposed, and are pollution-free. Will not cause harm to people.

The main beneficial effects of the present invention include: the prepared fiber-reinforced polymer-based flame-retardant composite material has excellent thermodynamic properties, and the material still has excellent rigidity and bending strength after being fired, so the composite material of the present invention can be applied in fire prevention In areas with high performance requirements and large loads.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

<source of material>

1. Plain weave E-glass fiber: purchased from Glasplies, UK, with a specification of 300 g/m ² .

2. Low-viscosity epoxy resin containing 1,4-butanediol diglycidyl ether: purchased from Huntsman Company, model LY5052.

3. Cycloaliphatic amine-modified hardener: purchased from Huntsman Company, model HY5052.

4. The mixture of polysilicic acid (acid source) and cellulose fiber (carbon source): purchased from Finland SateriFibres company, product name is VISIL, the weight ratio of cellulose fiber (carbon source) and polysilicic acid (acid source) is 7 :3.

5. Melamine: purchased from Aladdin Reagents (Shanghai) Co., Ltd.

6. Bis(octadecyl)pentaerythritol diphosphite: purchased from Aladdin Reagents (Shanghai) Co., Ltd., the product name is antioxidant 618.

Example 1:

(1) preparation of flame retardant polymer composition:

1200g of epoxy resin LY5052 (including hardener HY5052), 75g of VISIL, 75g of melamine and 150g of antioxidant 618 were mixed at room temperature by mechanical stirring to prepare the flame retardant polymer composition of this embodiment.

(II) Preparation of flame retardant composite board:

8 layers of plain weave E glass fibers (1500g in total) are placed in the RTM mold along the same direction, and after the mold is evacuated, the flame-retardant polymer composition prepared by (1) is injected into the mold under an atmospheric pressure Afterwards, the composition was solidified at 80° C. for 8 hours to obtain the composite material plate of the present embodiment, the composite material comprising 50wt% continuous glass fiber, 40wt% epoxy resin (including the content of HY5052 hardener), 2.5 wt% of Visil, 7.5wt% of melamine and antioxidant 618, as shown in Table 1.

Embodiment 2, 3:

Prepared in a method similar to Example 1, the difference between Examples 2 and 3 and Example 1 is that the amounts of each component are different, as shown in Table 1.

Comparative example 1:

Prepared in a similar manner to Example 1, this comparative example differs from Example 1 in that the flame retardant polymer composition does not contain melamine and antioxidant 618 and the amounts of other components are different, as shown in Table 1.

Comparative example 2:

Prepared in a similar manner to Example 1, this comparative example differs from Example 1 in that the flame retardant polymer composition does not contain VISIL and the amounts of other components are different, as shown in Table 1.

Comparative example 3:

Prepared by a method similar to Example 1, the difference between this comparative example and Example 1 is that the flame retardant polymer composition does not contain VISIL, nor does it contain melamine and antioxidant 618, but only epoxy resin and hardener, As shown in Table 1.

Table 1

Thermodynamic performance test:

(1) thermogravimetric analysis:

The composite material that embodiment 1 and comparative example 3 obtains is carried out thermogravimetric analysis with thermogravimetric analyzer (Swedish Mettler TGA/DSC analyzer), and the mass loss curve of these two composite materials with temperature variation is as shown in Figure 1, 1 in FIG. 1 represents the composite material of Example 1, and 2 represents the composite material of Comparative Example 3. During the test, the heating rate was 10°C/min, and the air flow was 100±5mL/min.

As can be seen from Figure 1, the mass loss of the two composite materials is relatively large between 350 and 425°C. After the temperature reaches 575°C, the remaining mass of the composite material in Comparative Example 3 is 50%, which is higher than this temperature , the polymer body burns out, leaving only glass fibers. Temperature is higher than 350 DEG C, and the mass loss of the flame-retardant composite material of embodiment 1 is smaller than comparative example 3, and the quaternary flame retardant that the present invention comprises carbon source, acid source, gas source and antioxidant simultaneously above explanation can improve The carbon residue rate of the composite material also has better residual mechanical properties because the flame-retardant composite material has more residual carbon residue rate after fire.

(II) Initial stiffness and three-point bending strength test:

As shown schematically in Fig. 2 and Fig. 3, the non-heat-radiating area of the composite material plates made in each embodiment and comparative example is subjected to heat-insulating treatment with a ceramic covering, and the heat-radiating area is a circular area with a diameter of 50 mm (Fig. 2 and the central circular black area in Figure 3), the distance from the center of the circle to the free side is 60mm. A circular area of the composite panel was irradiated for 540 seconds with a thermal radiation flux of ²⁵ kW/m2 in a cone calorimeter. After the composite material plate after local heat radiation is cooled to room temperature, the load-deflection curve of the composite material plate under the action of three-point bending load is measured by the material universal testing machine Instron3369, and the speed of 1mm per minute is passed through a hemispherical indenter with a diameter of 15mm. The composite plate is loaded, and the loading point is 15mm away from the free edge, and the load-deflection curve is obtained. The initial stiffness values and three-point bending strength values of the composite plate load-deflection curves after thermal radiation are listed in Table 2.

Table 2

As can be seen from the above test results, under the same test conditions, the addition of the quaternary flame retardant comprising carbon source, acid source, gas source and antioxidant simultaneously in the present invention makes the heating rate of the composite material slow down and The heat conduction rate becomes slower, so the exposure time of the composite material in thermal radiation can be significantly prolonged, the decomposition of the polymer in the composite material can be delayed, and the stiffness and strength of the composite material after fire can be improved.

In summary, when the quaternary flame retardant containing carbon source, acid source, gas source and antioxidant of the present invention is used to manufacture fiber-reinforced polymer-based flame-retardant composite materials, it can significantly prolong the thermal stability of the composite materials. The exposure time in the radiation delays the decomposition of the polymer in the composite material and improves the stiffness and strength of the composite material after fire. Therefore, the fiber-reinforced polymer-based flame-retardant composite material of the present invention has more char residue after fire. And it has better residual mechanical properties, and has better thermodynamic properties than composite materials in the prior art.

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (13)

1. an expansion type flame retardant, is characterized in that, described fire retardant comprises:

Carbon source, described carbon source is one or two or more kinds in cellulosic fibre, starch, dextrin;

Acid source, described acid source is polysilicon acid;

Source of the gas, described source of the gas be urea, trimeric cyanamide, polymeric amide one or two or more kinds; And

Oxidation inhibitor, described oxidation inhibitor is two (octadecyl) pentaerythritol diphosphites and/or hexadecyl pentaerythritol diphosphites;

And in described fire retardant, by weight, the ratio of both content summations of the content summation of described carbon source and acid source and source of the gas and oxidation inhibitor is 1:3 to 3:1;

And in described fire retardant, by weight, described carbon source is 2:8 to 8:2 with the content ratio of acid source;

And in described fire retardant, by weight, described source of the gas is 1:2 to 2:1 with the content ratio of oxidation inhibitor.

2. fire retardant as claimed in claim 1, it is characterized in that, described carbon source is cellulosic fibre.

3. fire retardant as claimed in claim 1, it is characterized in that, described source of the gas is trimeric cyanamide.

4. fire retardant as claimed in claim 1, is characterized in that, described oxidation inhibitor is two (octadecyl) pentaerythritol diphosphites.

5. fire retardant as claimed in claim 1, it is characterized in that, in described fire retardant, described carbon source is cellulosic fibre, and described acid source is polysilicon acid, and wherein the weight ratio of cellulosic fibre and polysilicon acid is 7:3.

6. fire retardant as claimed in claim 1, it is characterized in that, in described fire retardant, by weight, described source of the gas is 1:2 with the content ratio of oxidation inhibitor.

7. a flame retardant compositions, is characterized in that, comprises:

As the fire retardant as described in arbitrary in claim 1-6; And

The polymer precursor of polymer materials can formed after being heating and curing.

8. composition as claimed in claim 7, it is characterized in that, described polymer materials comprises one or two or more kinds in epoxy resin, nylon, polyolefine, polycarbonate.

9. a fiber-reinforced polymer-matrix flame-proof composite material, it is characterized in that, described matrix material comprises flame-proofed polymer material body and is arranged in the continuous fibre of described body, described flame-proofed polymer material body is integrated with continuous fibre, and described flame-proofed polymer material body obtains by making as the flame retardant compositions solidification as described in arbitrary in claim 7-8.

10. matrix material as claimed in claim 9, it is characterized in that, described matrix material has following thermomechanical property: matrix material is passing through 25kW/m ²thermal radiation flux radiation is again according to the test of ASTM7264-07 testing method after 540 seconds, and the initial stiffness of the matrix material after radiation is 0.205 to 0.225KN/mm, and three-point bending strength is 370 to 403MPa.

11. matrix materials as claimed in claim 9, it is characterized in that, described continuous fibre is selected from one or two or more kinds in glass fibre, carbon fiber, aramid fiber.

12. matrix materials as claimed in claim 9, it is characterized in that, described continuous fibre is form of fabric.

13. matrix materials as claimed in claim 9, it is characterized in that, with total restatement of described matrix material, the content summation of described carbon source and acid source is the 2.5wt% to 7.5wt% accounting for matrix material, the content summation of described source of the gas and oxidation inhibitor is the 2.5wt% to 7.5wt% accounting for matrix material, the content of described continuous fibre accounts for the 40wt% to 60wt% of matrix material, and the content of described polymer materials body is the 35wt% to 45wt% accounting for matrix material.