A flame-retardant low-viscosity light-cured BMC composite material and a preparation method thereof

Abstract

The invention belongs to the technical field of BMC composite materials, and specifically discloses a flame-retardant low-viscosity photocurable BMC composite material and a preparation method thereof. The raw materials include: 150-200 parts of BMC resin, 30-50 parts of magnesium hydroxide, 5-10 parts of metal compounds, 1-5 parts of curing agent, 1-5 parts of photoinitiator and 1-5 parts of defoamer. First, magnesium hydroxide and metal compounds are subjected to modification reaction in an organic solvent to obtain modified magnesium hydroxide; then, they are mixed with BMC resin to prepare composite material slurry; and then, they are mixed with curing agent, photoinitiator and defoamer to obtain flame-retardant low-viscosity photocurable BMC composite material. By loading metal compound precipitation on magnesium hydroxide, the hydroxyl group on the surface of magnesium hydroxide is greatly reduced, which significantly reduces the viscosity in the BMC composite material system, and the catalytic flame retardant effect of metal ions will make up for the deterioration of the flame retardant effect caused by the reduction of hydroxyl groups.

Description

Technical Field

[0001] The invention relates to the technical field of BMC composite materials, and in particular to a flame-retardant low-viscosity light-cured BMC composite material and a preparation method thereof. Background Art

[0002] Bulk plastic film (BMC) is a thermosetting plastic that is mixed with various inert fillers, reinforcements and stabilizers to form an adhesive "putty-like" composite material for compression molding or injection molding. It is suitable for molding by compression molding, transfer molding, injection molding and other processes. The products obtained have good mechanical properties, high dimensional stability, good surface finish, water resistance, oil resistance, excellent corrosion resistance, heat resistance, excellent electrical properties, etc., especially arc resistance can reach about 190s. It is made into resin slurry and is mainly used in electrical appliances, motors, radios, instruments, machinery manufacturing, chemical equipment, construction, transportation and national defense. Due to the requirements of the use field, BMC composite materials need to have excellent flame retardant properties. Flame retardants generally use aluminum hydroxide, but due to the high processing temperature of aluminum hydroxide, low flame retardant efficiency and high price, the industry is currently seeking new flame retardants to replace aluminum hydroxide. Among them, magnesium hydroxide is considered to be an effective flame retardant that can replace aluminum hydroxide. However, the current problem is that after magnesium hydroxide is added to the BMC composite material, the viscosity of the system rises rapidly, causing the material to solidify too quickly, which is not conducive to the storage and transportation of the composite material.

[0003] In response to the above problems, the current solutions include modifying the surface of magnesium hydroxide and reducing the viscosity of the system by lowering the pH value of magnesium hydroxide. However, although the use of traditional surface modifiers or silane coupling agents for modification can significantly improve the compatibility between magnesium hydroxide and composite materials, it cannot significantly change the pH value, so that the problem of excessive viscosity of the system still exists. If acidic substances are added for neutralization, the structure of magnesium hydroxide will be damaged, which will seriously affect the flame retardant effect of magnesium hydroxide. In summary, a good balance cannot be achieved between the viscosity problem and the flame retardant effect of magnesium hydroxide in the system.

[0004] Therefore, how to provide a modified magnesium hydroxide with good flame retardant effect and good structure, and introduce it into the BMC system to prepare a flame retardant low-viscosity photocurable BMC composite material is a difficult problem to be solved in this field. Summary of the invention

[0005] In view of this, the present invention provides a flame-retardant low-viscosity photocurable BMC composite material and a preparation method thereof, so as to solve the problem that the existing method cannot simultaneously ensure the low viscosity and excellent flame retardant effect of the composite material.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A flame-retardant low-viscosity light-cured BMC composite material is prepared from the following raw materials in parts by mass: 150-200 parts of BMC resin, 30-50 parts of magnesium hydroxide, 5-10 parts of metal compound, 1-5 parts of curing agent, 1-5 parts of photoinitiator and 1-5 parts of defoaming agent.

[0008] Preferably, the metal compound comprises one or more of zinc carbonate, zinc nitrate, nickel nitrate, cobalt nitrate, lanthanum nitrate, silver nitrate and cerium nitrate.

[0009] Preferably, the curing agent comprises one or more of trivinylamine, aminoethylpiperazine, m-phenylenediamine, diaminodiphenylmethane, triethylenetetramine, isophoronediamine, triethylenetetramine, tetraethylenepentamine and polyethylenepolyamine.

[0010] Preferably, the photoinitiator comprises one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, methyl benzoylformate, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin butyl ether.

[0011] Preferably, the defoaming agent includes one or more of polydimethylsiloxane, polymethylsiloxane, polyoxyethylene, polyoxypropylene glycerol ether, vinyl alcohol, and polyamide.

[0012] Another object of the present invention is to provide a method for preparing a flame-retardant low-viscosity light-cured BMC composite material, comprising the following steps:

[0013] 1) subjecting magnesium hydroxide and a metal compound to a modification reaction in an organic solvent to obtain modified magnesium hydroxide;

[0014] 2) mixing BMC resin with modified magnesium hydroxide to prepare a composite material slurry;

[0015] 3) The composite material slurry is mixed with a curing agent, a photoinitiator and a defoaming agent to obtain a flame retardant low-viscosity photocurable BMC composite material.

[0016] Preferably, the temperature of the modification reaction in step 1) is 70-130° C., and the time of the modification reaction is 30-120 min.

[0017] Preferably, the mixing temperature in step 2) is 30 to 150° C., and the mixing time is 10 to 90 minutes.

[0018] In the present invention, the metal ion deposition principle is used to deposit the metal ions on the surface of magnesium hydroxide in the form of hydroxide, which means that the metal compound is combined with the surface hydroxyl group on the magnesium hydroxide in a chemically bonded manner, which reduces the pH value of magnesium hydroxide, so that the viscosity is also significantly reduced when it is added to the BMC system, which can be seen from the obvious reduction of the number of hydroxyl groups on the surface of magnesium hydroxide. At the same time, due to the reduction of the number of hydroxyl groups on the surface of magnesium hydroxide, its flame retardant effect should have been deteriorated, but due to the unique catalytic flame retardant properties of metal ions in metal oxides, it can promote the rapid carbonization of polymer materials during the combustion process, and as a result, a dense carbon layer can be generated. This is because during the combustion process, the metal ions can catalyze the alkane molecular chains of the polymer materials to form highly unsaturated hydrocarbons, which are adsorbed on the magnesium oxide produced by the decomposition of magnesium hydroxide, so that the flame retardant properties of the composite material are greatly enhanced.

[0019] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) In the flame-retardant low-viscosity light-cured BMC composite material system prepared by the present invention, a metal compound is precipitated on magnesium hydroxide, and the surface hydroxyl groups of the modified magnesium hydroxide obtained are greatly reduced. Its structure can significantly reduce the viscosity of the BMC composite material system, so that the viscosity of the modified magnesium hydroxide system is lower than that of the traditional aluminum hydroxide system. And it has more advantages in price.

[0021] (2) The present invention prepares a flame-retardant low-viscosity photocurable BMC composite material by adding modified magnesium hydroxide to a traditional BMC resin, and has good flame retardant properties. The addition of metal ions can play a role in catalytic flame retardancy, and the deterioration of the flame retardant effect caused by the reduction of hydroxyl groups on the surface of magnesium hydroxide will be compensated, thereby improving the flame retardant properties of the overall composite material. The flame-retardant low-viscosity photocurable BMC composite material prepared by the present invention has excellent flame retardant properties, viscosity ≤3200, solid content>60%, limiting oxygen index ≥37.8, maximum smoke density ≤69.00, and smoke density grade ≤58.46. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0023] Figure 1 FT-IR images of magnesium hydroxide before and after modification in Example 1;

[0024] Figure 2This is a SEM image of the surface of unmodified magnesium hydroxide in Example 1;

[0025] Figure 3 This is the SEM image of the surface of modified magnesium hydroxide in Example 1. DETAILED DESCRIPTION

[0026] The present invention provides a flame-retardant low-viscosity photocurable BMC composite material, which is prepared from the following raw materials in parts by mass: 150-200 parts of BMC resin, 30-50 parts of magnesium hydroxide, 5-10 parts of metal compound, 1-5 parts of curing agent, 1-5 parts of photoinitiator and 1-5 parts of defoaming agent.

[0027] In the present invention, under the above ratio, the added amount of BMC resin can be specifically 160 parts, 170 parts, 180 parts, and 190 parts; the added amount of magnesium hydroxide can be specifically 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, and 48 parts; the added amount of metal compound can be specifically 6 parts, 7 parts, 8 parts, and 9 parts; the added amount of curing agent can be specifically 2 parts, 3 parts, and 4 parts; the added amount of photoinitiator can be specifically 2 parts, 3 parts, and 4 parts; the added amount of defoaming agent can be specifically 2 parts, 3 parts, and 4 parts.

[0028] In the present invention, the magnesium hydroxide is preferably ultrafine magnesium hydroxide; the mesh number of the ultrafine magnesium hydroxide is preferably ≥2000 mesh, specifically 2500 mesh, 3000 mesh, 4000 mesh, 5000 mesh, 6000 mesh. The ultrafine magnesium hydroxide of the present invention is preferably derived from Jiangxi Guangyuan Chemical Group, the product number is GY-6000, which is an ultra-high mesh magnesium hydroxide product produced by crushing the raw ore, and has strong hydrophilicity. The mesh number of the magnesium hydroxide preferably used in the present invention is 6000 mesh.

[0029] In the present invention, the metal compound comprises one or more of zinc carbonate, zinc nitrate, nickel nitrate, cobalt nitrate, lanthanum nitrate, silver nitrate and cerium nitrate.

[0030] In the present invention, the curing agent comprises one or more of trivinylamine, aminoethylpiperazine, m-phenylenediamine, diaminodiphenylmethane, triethylenetetramine, isophoronediamine, triethylenetetramine, tetraethylenepentamine and polyethylenepolyamine.

[0031] In the present invention, the photoinitiator comprises one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, methyl benzoylformate, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin butyl ether.

[0032] In the present invention, the defoaming agent includes one or more of polydimethylsiloxane, polymethylsiloxane, polyoxyethylene, polyoxypropylene glycerol ether, vinyl alcohol, and polyamide.

[0033] The present invention also provides a method for preparing a flame-retardant low-viscosity light-cured BMC composite material, comprising the following steps:

[0034] 1) subjecting magnesium hydroxide and a metal compound to a modification reaction in an organic solvent to obtain modified magnesium hydroxide;

[0035] 2) mixing BMC resin with modified magnesium hydroxide to prepare a composite material slurry;

[0036] 3) The composite material slurry is mixed with a curing agent, a photoinitiator and a defoaming agent to obtain a flame retardant low-viscosity photocurable BMC composite material.

[0037] In the present invention, the organic solvent in step 1) is preferably an alcohol solvent, specifically ethanol. In the present invention, the organic solvent plays a dissolving role.

[0038] In the present invention, the temperature of the modification reaction in step 1) is 70-130°C, specifically 80°C, 90°C, 100°C, 110°C, 120°C; the time of the modification reaction is 30-120min, specifically 40min, 50min, 60min, 80min, 100min.

[0039] In the present invention, the mixing temperature in step 2) is 30-150°C, specifically 40°C, 50°C, 60°C, 80°C, 100°C, 120°C; the mixing time is 10-90min, specifically 20min, 30min, 40min, 50min, 60min, 80min.

[0040] In the present invention, the modification reaction in step 1) and the mixing operation in step (2) are preferably independently carried out under stirring conditions, wherein the stirring speed is independently 400 to 1200 rpm, specifically 500 rpm, 600 rpm, 800 rpm, 1000 rpm.

[0041] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The magnesium hydroxide in each embodiment and comparative example of the present invention is ultrafine magnesium hydroxide, which is sourced from Jiangxi Guangyuan Chemical Group, with a product number of GY-6000 and a mesh size of 6000 mesh; the BMC resin is sourced from 3301 glass fiber reinforced plastic resin produced by Xinxin New Material Technology Co., Ltd. The above common commercially available materials are not considered as limitations on magnesium hydroxide and BMC resin.

[0043] Example 1

[0044] 50g of magnesium hydroxide, 5g of zinc nitrate and 150ml of ethanol solvent were mixed and reacted at 120°C for 50min under stirring conditions of 800rpm to obtain modified magnesium hydroxide; the FT-IR images of magnesium hydroxide before and after modification are as follows: Figure 1 As shown, the SEM image of the surface of unmodified magnesium hydroxide is as follows Figure 2 As shown, the SEM image of the surface of modified magnesium hydroxide is as follows Figure 3 shown.

[0045] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of trivinylamine, 1 g of methyl benzoylformate and 2 g of vinyl alcohol, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0046] Example 2

[0047] 50 g of magnesium hydroxide, 5 g of nickel nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0048] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of triethylenetetramine, 1 g of benzoin dimethyl ether and 2 g of polyoxypropylene glycerol ether, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0049] Example 3

[0050] 50 g of magnesium hydroxide, 5 g of cobalt nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0051] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of isophorone diamine, 1 g of benzoin isopropyl ether and 2 g of polyoxyethylene, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0052] Example 4

[0053] 50 g of magnesium hydroxide, 5 g of silver nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0054] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of triethylenetetramine, 1 g of benzoin butyl ether and 2 g of methylsiloxane, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0055] Example 5

[0056] 50 g of magnesium hydroxide, 5 g of zinc nitrate and 150 ml of ethanol solvent were mixed and reacted at 100° C. for 40 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0057] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of trivinylamine, 1 g of methyl benzoylformate and 2 g of vinyl alcohol, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0058] Example 6

[0059] 50 g of magnesium hydroxide, 5 g of nickel nitrate and 150 ml of ethanol solvent were mixed and reacted at 100° C. for 40 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0060] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of triethylenetetramine, 1 g of benzoin dimethyl ether and 2 g of polyoxypropylene glycerol ether, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0061] Example 7

[0062] 50 g of magnesium hydroxide, 5 g of cobalt nitrate and 150 ml of ethanol solvent were mixed and reacted at 100° C. for 40 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0063] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of isophorone diamine, 1 g of benzoin isopropyl ether and 2 g of polyoxyethylene, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0064] Example 8

[0065] 50 g of magnesium hydroxide, 5 g of silver nitrate and 150 ml of ethanol solvent were mixed and reacted at 100° C. for 40 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0066] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of triethylenetetramine, 1 g of benzoin butyl ether and 2 g of methylsiloxane, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0067] Example 9

[0068] 50 g of magnesium hydroxide, 5 g of zinc nitrate and 150 ml of ethanol solvent were mixed and reacted at 90° C. for 35 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0069] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of trivinylamine, 1 g of methyl benzoylformate and 1 g of vinyl alcohol, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0070] Example 10

[0071] 50 g of magnesium hydroxide, 5 g of nickel nitrate and 150 ml of ethanol solvent were mixed and reacted at 90° C. for 35 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0072] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of triethylenetetramine, 1 g of benzoin dimethyl ether and 1 g of polyoxypropylene glycerol ether, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0073] Embodiment 11

[0074] 50 g of magnesium hydroxide, 5 g of cobalt nitrate and 150 ml of ethanol solvent were mixed and reacted at 90° C. for 35 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0075] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of isophorone diamine, 1 g of benzoin isopropyl ether and 1 g of polyoxyethylene, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0076] Example 12

[0077] 50 g of magnesium hydroxide, 5 g of silver nitrate and 150 ml of ethanol solvent were mixed and reacted at 90° C. for 35 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0078] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 1 g of triethylenetetramine, 1 g of benzoin butyl ether and 1 g of methylsiloxane, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0079] Example 13

[0080] 50 g of magnesium hydroxide, 8 g of zinc nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0081] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of trivinylamine, 1 g of methyl benzoylformate and 2 g of vinyl alcohol, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0082] Embodiment 14

[0083] 50 g of magnesium hydroxide, 8 g of nickel nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0084] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of triethylenetetramine, 1 g of benzoin dimethyl ether and 2 g of polyoxypropylene glycerol ether, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0085] Embodiment 15

[0086] 50 g of magnesium hydroxide, 8 g of cobalt nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0087] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of isophorone diamine, 1 g of benzoin isopropyl ether and 2 g of polyoxyethylene, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0088] Example 16

[0089] 50 g of magnesium hydroxide, 8 g of silver nitrate and 150 ml of ethanol solvent were mixed and reacted at 120° C. for 50 min under stirring conditions of 800 rpm to obtain modified magnesium hydroxide;

[0090] The modified magnesium hydroxide and 200 g of BMC resin were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of triethylenetetramine, 1 g of benzoin butyl ether and 2 g of methylsiloxane, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0091] Comparative Example 1

[0092] 200 g of BMC resin, 2 g of trivinylamine, 1 g of methyl benzoylformate and 2 g of vinyl alcohol were mixed, and reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a flame-retardant low-viscosity photocurable BMC composite material.

[0093] Comparative Example 2

[0094] 200 g of BMC resin and 50 g of unmodified magnesium hydroxide were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of trivinylamine, 1 g of methyl benzoylformate and 2 g of vinyl alcohol, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0095] Comparative Example 3

[0096] 200 g of BMC resin and 50 g of aluminum hydroxide were reacted at 30° C. for 15 min under stirring conditions of 800 rpm to obtain a slurry. The slurry was mixed with 2 g of trivinylamine, 1 g of methyl benzoylformate and 2 g of vinyl alcohol, and the mixture was stirred for 15 min to obtain a flame-retardant, low-viscosity, photocurable BMC composite material.

[0097] The performance tests were performed on the BMC composite materials obtained in the above Examples 1 to 16 and Comparative Examples 1 to 3:

[0098] (1) Viscosity test: Tested in accordance with GB / T10247-2008 standard.

[0099] (2) Determination of solid content: 1 g of the composite material was placed in a watch glass, dried in an oven at 120°C, and the remaining mass was weighed. The solid content was calculated from the ratio of the remaining mass to the initial mass.

[0100] (3) Limiting oxygen index test: Tested in accordance with GB / T2406.2-2009 standard.

[0101] (4) Maximum smoke density and smoke density level test: Tested in accordance with GB / T8627-2007 standard.

[0102] The test results are shown in Table 1:

[0103] Table 1 Test results of composite materials obtained from Examples 1 to 16 and Comparative Examples 1 to 3

[0104]

[0105]

[0106] It can be seen from the results of Example 1 and Comparative Example 1 that, without the addition of magnesium hydroxide, the flame retardant properties of the BMC composite material are too different, and the addition of magnesium hydroxide has a significant improvement in the limiting oxygen index, maximum smoke density and smoke density level of the composite material; It can be seen from the results of Example 1 and Comparative Example 2 that there are a large number of hydroxyl structures on the surface of the unmodified magnesium hydroxide, and the introduction of the metal compound will not affect the intrinsic structure of the magnesium hydroxide, but only change its surface group; Figure 1 It can be seen that the introduction of metal compounds can significantly reduce the amount of hydroxyl groups on the surface of magnesium hydroxide, causing a decrease in the pH value of magnesium hydroxide; Figure 2 and Figure 3 It can be seen that the surface of magnesium hydroxide has obvious changes before and after modification, which makes the viscosity of the system increase rapidly when unmodified magnesium hydroxide is added to the BMC composite material, while the addition of modified magnesium hydroxide will significantly reduce the viscosity of the system. At the same time, the introduction of metal compounds makes the flame retardant effect brought by magnesium hydroxide improve. From the results of Example 1 and Comparative Example 3, it can be seen that the modified magnesium hydroxide can effectively replace aluminum hydroxide in the BMC system, and has obvious advantages in viscosity and flame retardant properties, and is more price-friendly, which can broaden the application of modified magnesium hydroxide and further obtain a BMC composite material with better performance.

[0107] From the above, it can be seen that the flame-retardant low-viscosity photocurable BMC composite resin prepared by the present invention has a viscosity of ≤3200, a solid content of >60%, a limiting oxygen index of ≥37.8, a maximum smoke density of ≤69.00, and a smoke density grade of ≤58.46, which makes it have high added value and further expands the application field of waterborne polyurethane resin.

[0108] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0109] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flame-retardant, low-viscosity, light-cured BMC composite material, characterized in that: The invention is prepared from the following raw materials in parts by weight: 150-200 parts of BMC resin, 30-50 parts of magnesium hydroxide, 5-10 parts of metal compound, 1-5 parts of curing agent, 1-5 parts of photoinitiator and 1-5 parts of defoaming agent; The metal compound comprises one or more of zinc carbonate, zinc nitrate, nickel nitrate, cobalt nitrate, lanthanum nitrate, silver nitrate and cerium nitrate; The BMC resin is 3301 fiberglass resin produced by Xinxin New Material Technology Co., Ltd.

2. The flame-retardant low-viscosity light-cured BMC composite material according to claim 1, characterized in that: The curing agent comprises one or more of trivinylamine, aminoethylpiperazine, m-phenylenediamine, diaminodiphenylmethane, triethylenetetramine, isophoronediamine, triethylenetetramine, tetraethylenepentamine and polyethylenepolyamine.

3. The flame-retardant low-viscosity light-cured BMC composite material according to claim 2, characterized in that: The photoinitiator comprises one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, methyl benzoylformate, benzoin dimethyl ether, benzoin isopropyl ether and benzoin butyl ether.

4. The flame-retardant low-viscosity light-cured BMC composite material according to claim 3, characterized in that: The defoaming agent includes one or more of polydimethylsiloxane, polymethylsiloxane, polyoxyethylene, polyoxypropylene glycerol ether, vinyl alcohol, and polyamide.

5. The method for preparing a flame-retardant low-viscosity light-cured BMC composite material according to any one of claims 1 to 4, characterized in that: The steps include: 1) subjecting magnesium hydroxide and a metal compound to a modification reaction in an organic solvent to obtain modified magnesium hydroxide; 2) Mixing BMC resin with modified magnesium hydroxide to prepare a composite material slurry; 3) The composite material slurry is mixed with a curing agent, a photoinitiator and a defoaming agent to obtain a flame retardant low-viscosity photocurable BMC composite material.

6. The method for preparing a flame-retardant low-viscosity light-cured BMC composite material according to claim 5, characterized in that: In the step 1), the temperature of the modification reaction is 70-130° C., and the time of the modification reaction is 30-120 min.

7. The method for preparing a flame-retardant low-viscosity light-cured BMC composite material according to claim 5 or 6, characterized in that: The mixing temperature in step 2) is 30-150° C., and the mixing time is 10-90 min.

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