Glass fiber reinforced flame retardant vinyl ester resin composite material and preparation method thereof

Abstract

The present invention belongs to the technical field of composite materials, and specifically relates to a glass fiber reinforced flame-retardant vinyl ester resin composite material and a preparation method thereof. The preparation method of the glass fiber reinforced flame-retardant vinyl ester resin composite material of the present invention comprises the following steps: S1. 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) reacts with hydrogen peroxide to obtain DOPO-OH. S2. DOPO-OH reacts with piperazine (PIP) to obtain DOPO-OH-PIP. S3. Phosphoric acid reacts with 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione to obtain the product PTTA. S4. Flame retardant DPPTTA is obtained by reacting PTTA with DOPO-OH-PIP. S5. The obtained DPPTTA flame retardant, methyl ethyl ketone peroxide, N,N-dimethylformamide, cobalt naphthenate, and vinyl ester resin are thoroughly mixed, and then gradually added to a mold containing glass fiber for curing to obtain the glass fiber reinforced flame-retardant vinyl ester resin composite material.

Description

Technical Field

[0001] The present invention relates to the field of composite materials, and more particularly to a glass fiber reinforced flame retardant vinyl ester resin composite material and a preparation method thereof. Background Art

[0002] Vinyl ester resin (VER), formed by the reaction of epoxy oligomers with unsaturated carboxylic acids such as acrylic acid or methacrylic acid, is a representative thermosetting polymer and unsaturated polyester resin. The viscosity of the resulting product is controlled by the molar mass of the VER and the amount of styrene. As a type of unsaturated polyester resin, vinyl ester resins offer advantages such as high curing efficiency, good wettability, corrosion resistance, and relatively low cost, making them widely used in glass fiber reinforced composites. However, they are highly flammable and produce thick smoke upon ignition. Therefore, conventional VER cannot meet the high flame retardancy requirements of glass fiber reinforced composites, significantly limiting their application. To address this, various functional molecules or oligomeric flame retardants are being used as additives to flame-retard VER for the preparation of VER-based glass fiber reinforced composites. The application of organic flame retardants is rapidly developing. They can be used in halogen-based flame retardants containing elements such as Si, N, P, and B, as well as halogen-free composite systems. However, due to the large amount of smoke and harmful substances produced during combustion, many halogen-based flame retardants have recently been abandoned due to environmental concerns. Therefore, it is of great significance to develop a highly efficient flame-retardant halogen-free NP flame retardant to prepare flame-retardant VER-based glass fiber reinforced composites. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a glass fiber reinforced flame retardant vinyl ester resin composite material and a preparation method thereof.

[0004] The purpose of the present invention is achieved through the following technical solution: A method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material comprises the following steps.

[0005] S1.9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) reacts with hydrogen peroxide to obtain DOPO-OH.

[0006] S2. DOPO-OH reacts with piperazine (PIP) to obtain DOPO-OH-PIP.

[0007] S3. Phosphoric acid reacts with 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione to obtain the product PTTA.

[0008] S4. The flame retardant DPPTTA was obtained by reacting PTTA and DOPO-OH-PIP.

[0009] S5. The obtained DPPTTA flame retardant, methyl ethyl ketone peroxide, N,N-dimethylformamide, cobalt cyclopentane and vinyl ester resin are fully mixed and gradually added into a mold containing glass fiber for curing to obtain a glass fiber reinforced flame retardant vinyl ester resin composite material.

[0010] Specifically, in step S1, 10 parts by mass of DOPO were dissolved in 55 parts by mass of ethanol, 81 parts by mass of hydrogen peroxide were added dropwise, and the solution was heated to 80° C. and then kept warm for 10 hours.

[0011] Furthermore, in step S1, the solution is cooled to room temperature, DOPO-OH is filtered, washed and separated with ethanol, and then dried in a vacuum oven at 80° C. for 10 to 12 hours to obtain DOPO-OH.

[0012] Specifically, the reaction pathway in step S1 is as follows:

[0013]

[0014] Furthermore, in step S2, 5 parts by mass of DOPO-OH prepared in step S1, 1.9 parts by mass of piperazine, and 30 parts by mass of ethanol were added to a flask and stirred for reaction for 2.5 hours to obtain DOPO-OH-PIP.

[0015] Specifically, the reaction pathway in step S2 is as follows:

[0016]

[0017] Furthermore, in step S3, 10 parts by mass of phosphoric acid and 9 parts by mass of 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione are heated to 120° C. and reacted for 4 to 5 hours to obtain PTTA.

[0018] Specifically, the reaction path in step S3 is as follows:

[0019]

[0020] Specifically, in step S4, 18.5 parts by mass of PTTA was added to the DOPO-OH-PIP prepared in step S2 and stirred for 2 hours. The precipitated DPPTTA was collected by vacuum distillation and washed several times with distilled water.

[0021] Furthermore, the DPPTTA obtained in step S4 was dried in a vacuum drying oven at 80° C. for 10 h to obtain a DPPTTA flame retardant.

[0022] More specifically, the reaction pathway in step S4 is as follows:

[0023]

[0024] Furthermore, in step S5, 60 to 100 parts by mass of vinyl ester resin, 2 parts of methyl ethyl ketone peroxide, 1.5 parts of N,N-dimethylformamide, 2 parts of cobalt cyclohexaneate, and 10 to 40 parts of the prepared DPPTTA flame retardant are vacuum stirred for 1 hour.

[0025] Specifically, the curing temperature in step S5 is 120-140° C., and the curing time is 1.5 h.

[0026] A glass fiber reinforced flame retardant vinyl ester resin composite material is prepared by the method.

[0027] The beneficial effects of the present invention are:

[0028] (1) A new NP synergistic flame retardant DPPTTA was synthesized.

[0029] (2) Flame retardants do not contain halogen elements, have low toxicity, do not produce a lot of smoke, and are environmentally friendly.

[0030] (3) The prepared glass fiber reinforced flame retardant vinyl ester resin composite material has excellent flame retardancy and mechanical properties.

[0031] Description of the accompanying tables and figures

[0032] Figure 1 The tensile strength and flexural strength of the examples and comparative examples are shown in FIG. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described in detail below, but the protection scope of the present invention is not limited to the following.

[0034] Example 1

[0035] A glass fiber reinforced flame retardant vinyl ester resin composite material and a preparation method thereof, comprising the following steps:

[0036] S1. Dissolve 10 parts DOPO in 55 parts ethanol, then add 81 parts hydrogen peroxide dropwise. Heat the solution to 80°C and maintain this temperature for 10 hours. Then, cool the solution to room temperature, filter the DOPO-OH, wash with ethanol, and dry in a vacuum oven at 80°C for 10-12 hours to obtain DOPO-OH.

[0037] S2. Add 5 parts of DOPO-OH prepared in step S1, 1.9 parts of piperazine and 30 parts of ethanol into a flask and stir to react for 2.5 hours to obtain DOPO-OH-PIP.

[0038] S3. Heat 10 parts of phosphoric acid and 9 parts of 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione to 120° C. and react for 4 to 5 hours to obtain PTTA.

[0039] S4. Add 18.5 parts of PTTA to the DOPO-OH-PIP prepared in step S2 and stir for 2 hours. Collect the precipitated DPPTTA by vacuum distillation and wash it several times with distilled water. After washing, dry it in a vacuum oven at 80°C for 10 hours.

[0040] S5. Combine 90 parts of vinyl ester resin, 2 parts of methyl ethyl ketone peroxide, 1.5 parts of N,N-dimethylformamide, 2 parts of cobalt naphthenate, and 10 parts of the prepared DPPTTA flame retardant and stir under vacuum for 1 hour. Gradually add this mixture to a mold containing glass fiber and cure at a curing temperature of 120-140°C for 1.5 hours.

[0041] Example 2

[0042] 80 parts vinyl ester resin, 2 parts methyl ethyl ketone peroxide, 1.5 parts N,N-dimethylformamide, 2 parts cobalt naphthenate, and 20 parts prepared DPPTTA flame retardant were stirred under vacuum for 1 hour. This mixture was gradually added to a mold containing glass fiber and cured at a curing temperature of 120-140°C for 1.5 hours.

[0043] Example 3

[0044] Combine 70 parts vinyl ester resin, 2 parts methyl ethyl ketone peroxide, 1.5 parts N,N-dimethylformamide, 2 parts cobalt naphthenate, and 30 parts of the prepared DPPTTA flame retardant and stir under vacuum for 1 hour. Gradually add this mixture to a mold containing glass fiber and cure at 120-140°C for 1.5 hours.

[0045] Example 4

[0046] Combine 60 parts vinyl ester resin, 2 parts methyl ethyl ketone peroxide, 1.5 parts N,N-dimethylformamide, 2 parts cobalt naphthenate, and 40 parts of the prepared DPPTTA flame retardant and stir under vacuum for 1 hour. Gradually add this mixture to a mold containing glass fiber and cure at a temperature of 120-140°C for 1.5 hours.

[0047] Comparative Example 1

[0048] A glass fiber reinforced flame retardant vinyl ester resin composite material and a preparation method thereof, comprising the following steps:

[0049] S1. Dissolve 10 parts DOPO in 55 parts ethanol, then add 81 parts hydrogen peroxide dropwise. Heat the solution to 80°C and maintain this temperature for 10 hours. Then, cool the solution to room temperature, filter the DOPO-OH, wash with ethanol, and dry in a vacuum oven at 80°C for 10-12 hours to obtain DOPO-OH.

[0050] S2. Add 5 parts of DOPO-OH prepared in step S1, 1.9 parts of piperazine and 30 parts of ethanol into a flask and stir to react for 2.5 hours to obtain DOPO-OH-PIP.

[0051] S3. Heat 10 parts of phosphoric acid and 9 parts of 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione to 120° C. and react for 4 to 5 hours to obtain PTTA.

[0052] S4. Add 18.5 parts of PTTA to the DOPO-OH-PIP prepared in step S2 and stir for 2 hours. Collect the precipitated DPPTTA by vacuum distillation and wash it several times with distilled water. After washing, dry it in a vacuum oven at 80°C for 10 hours.

[0053] S5. Mix 100 parts vinyl ester resin, 2 parts methyl ethyl ketone peroxide, 1.5 parts N,N-dimethylformamide, and 2 parts cobalt naphthenate, and stir under vacuum for 1 hour. Gradually add this mixture to a mold containing glass fiber and cure at a curing temperature of 120-140°C for 1.5 hours.

[0054] Table 2 LOI and UL-94 test results of Examples and Comparative Examples

[0055]

[0056] According to the test results of Comparative Example 1 and Example in Table 2, the LOI value of Comparative Example 1 is low, and it does not have a UL-94 rating, and its dripping material can ignite cotton. However, after adding only 10 parts of flame retardant DPPTTA, the LOI value of Example 1 has been significantly improved. As the flame retardant content continues to increase, the LOI value of Example 1 reaches 31.2%, and the UL-94 rating reaches V-0, indicating that the addition of DPPTTA significantly improves the flame retardancy of VER. In addition, Figure 1 The tensile strength and flexural strength of the examples and comparative examples

[0057] Table 1 Examples and Comparative Examples

[0058] Components Example 1 Example 2 Example 3 Example 4 Comparative Example 1 vinyl ester resin 90 80 70 60 100 Methyl ethyl ketone peroxide 2 2 2 2 2 N,N-Dimethylformamide 1.5 1.5 1.5 1.5 1.5 Cobalt naphthenate 2 2 2 2 2 DPPTTA 10 20 30 40 0

[0059] As can be seen, although the tensile strength and flexural strength of the composite material decreased somewhat with the addition of DPPTTA, the tensile strength reached over 470 MPa and the flexural strength reached over 600 MPa, respectively, indicating that the addition of DPPTTA did not significantly reduce the mechanical properties of the composite material. Therefore, the addition of synthesized DPPTTA to VER has practical significance for flame retardancy under high-strength conditions, while the effects of the present invention cannot be achieved without DPPTTA.

[0060] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material, characterized in that: The steps include: S1.9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) reacts with hydrogen peroxide to obtain DOPO-OH; S2. DOPO-OH reacts with piperazine (PIP) to obtain DOPO-OH-PIP; S3. phosphoric acid reacts with 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione to obtain the product PTTA; S4. The flame retardant DPPTTA was obtained by reacting PTTA with DOPO-OH-PIP; S5. The obtained DPPTTA flame retardant, methyl ethyl ketone peroxide, N,N-dimethylformamide, cobalt cyclopentane and vinyl ester resin are fully mixed and placed into a mold together with glass fiber for curing to obtain a glass fiber reinforced flame retardant vinyl ester resin composite material.

2. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S1, 10 parts of DOPO were dissolved in 55 parts of ethanol, and then 81 parts of hydrogen peroxide were added dropwise. The solution was heated to 80° C. and kept warm for 10 hours.

3. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S1, the solution is cooled to room temperature, DOPO-OH is filtered, washed and separated with ethanol, and then dried in a vacuum oven at 80° C. for 10 to 12 hours to obtain DOPO-OH.

4. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S2, 5 parts by mass of DOPO-OH, 1.9 parts by mass of piperazine and 30 parts by mass of ethanol were added to a flask and stirred for reaction for 2.5 hours to obtain DOPO-OH-PIP.

5. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S3, 10 parts by mass of phosphoric acid and 9 parts of 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazine-2,4,6-trione were heated to 120° C. and reacted for 4 to 5 hours to obtain PTTA.

6. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S4, 18.5 parts by mass of PTTA were added to the DOPO-OH-PIP prepared in step S2 and stirred for reaction for 2 hours. The precipitated DPPTTA was collected by vacuum distillation and washed several times with distilled water.

7. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: The DPPTTA obtained in step S4 was dried in a vacuum drying oven at 80° C. for 10 h to obtain a DPPTTA flame retardant.

8. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S5, 60 to 100 parts by mass of vinyl ester resin, 2 parts of methyl ethyl ketone peroxide, 1.5 parts of N,N-dimethylformamide, 2 parts of cobalt cyclohexaneate, and 10 to 40 parts of the prepared DPPTTA flame retardant are vacuum-stirred for 1 hour.

9. The method for preparing a glass fiber reinforced flame retardant vinyl ester resin composite material according to claim 1, characterized in that: In step S5, the curing temperature is 120-140° C., and the curing time is 1.5 hours.

10. A glass fiber reinforced flame retardant vinyl ester resin composite material, characterized in that: A glass fiber reinforced flame retardant vinyl ester resin composite material is prepared by the preparation method according to any one of claims 1 to 9.

Images