High-tenacity flame-retardant polyester resin and method for producing the same

Abstract

This invention discloses a high-toughness flame-retardant polyester resin. The invention also discloses a method for preparing the aforementioned high-toughness flame-retardant polyester resin, comprising: preparing a flame-retardant preform; under nitrogen protection, adding methyl ethylene glycol, 1,2-propanediol, and 1,4-butanediol to a reaction vessel, then adding fumaric acid, and heating to 200-210℃ for polycondensation to obtain a prepolymer resin; cooling the prepolymer resin, adding phthalic anhydride, dehydrated malic anhydride, hydroquinone, and the flame-retardant preform, and heating to 200-210℃ for polycondensation to obtain a composite polyester resin; mixing granite aggregate and the composite polyester resin evenly, adding styrene, calcium carbonate, and a curing accelerator and stirring for 1-2 hours, then adding a diluent, plasticizer, curing agent, and quartz tailings and mixing evenly, pouring into a mold, vibrating for 15-60 minutes; curing at 30-50℃ for 10-20 hours, and then curing at room temperature for 1-5 hours after demolding to obtain the high-toughness flame-retardant polyester resin.

Description

Technical Field

[0001] This invention relates to the field of polyester resin technology, and in particular to a high-toughness flame-retardant polyester resin and its preparation method. Background Technology

[0002] Artificial stone is one of the main building decoration materials in today's society. It can replace natural stone, high-grade ceramics, wood, and metal decorative materials, and belongs to green and environmentally friendly high-grade building materials. Polyester resin-based artificial stone uses polyester resin or epoxy resin as a binder and adds a certain amount of filler. It has the characteristics of being beautiful, practical, safe, and environmentally friendly, and is the fastest-growing variety of artificial stone.

[0003] Among the various types of artificial stone, engineered stone is the most widely used. It is made by using crushed or powdered carbonate stone (marble, limestone, etc.) as the main filler and polyester resin or other high-molecular polymers as a binder, processed through specific techniques. It is also known as artificial marble or engineered stone. Currently, engineered stone resin is widely used in various indoor spaces such as kitchen countertops, bathroom vanities, window sills, dining tables, and commercial countertops, and the industry is showing a rapid growth trend.

[0004] Polyester resin is one of the most commonly used thermosetting resins, generally a linear polymer compound with ester bonds formed by the condensation polymerization of diacids and diols. However, polyester resin has poor heat resistance and flame retardancy. Meanwhile, calcium carbonate is the most important filler in artificial stone resin, generally accounting for more than 75% of its mass. The higher the filler content, the less resin is used, resulting in lower production costs and a more environmentally friendly product. However, due to the inorganic nature of calcium carbonate powder, it not only has poor compatibility with polyester resin but also exhibits poor wetting of the polyester resin, preventing further increases in the amount of calcium carbonate powder added.

[0005] Currently, there is great potential in researching how to prepare a flame-retardant polyester resin that enhances the toughness, flame retardancy, and mechanical strength of the product while increasing the calcium carbonate content. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a high-toughness flame-retardant polyester resin and its preparation method.

[0007] A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add polyacrylic acid to sodium hydroxide solution and stir evenly. Adjust the temperature to 30-40℃, add calcium chloride and stir for 1-2 hours, add sodium carbonate and stir for 10-20 hours, centrifuge, wash, and vacuum dry; then add to water, add aluminum magnesium hydrotalcite and graphene oxide, grind for 1-2 hours, dry, and pulverize to obtain flame retardant preform. S2. Under nitrogen protection, methyl ethylene glycol, 1,2-propanediol, and 1,4-butanediol are added to a reactor, followed by the addition of fumaric acid. The mixture is gradually heated to 205-215℃ for polycondensation until the acid value drops to 15-25 mg KOH / g, yielding a prepolymer resin. The prepolymer resin is then cooled to 155-165℃, and phthalic anhydride, dehydrated malic anhydride, hydroquinone, and flame-retardant preform are added. The mixture is gradually heated to 200-210℃ for polycondensation until the acid value reaches 6-12 mg KOH / g, yielding a composite polyester resin. S3. Mix granite aggregate and composite polyester resin evenly, add styrene, calcium carbonate and curing accelerator and continue stirring for 1-2 hours. Then add diluent, plasticizer, curing agent and quartz tailings and mix evenly. Pour into mold and vibrate for 15-60 minutes. Cure at 30-50℃ for 10-20 hours. After demolding, cure at room temperature for 1-5 hours to obtain high toughness flame retardant polyester resin.

[0008] Preferably, in S1, the mass ratio of polyacrylic acid, calcium chloride, sodium carbonate, aluminum magnesium hydrotalcite, and graphene oxide is 1-2:5-10:2-6:1-2:1-3.

[0009] Preferably, in S1, the grinding pressure is 1.2-3.5 MPa and the grinding speed is 1000-5000 r / min.

[0010] Preferably, in S2, the mass ratio of methyl ethylene glycol, 1,2-propanediol, 1,4-butanediol, trans-butenedioic acid, phthalic anhydride, dehydrated malic anhydride, hydroquinone, and flame-retardant preform is 6-10:4-8:10-16:8-16:15-23:4-9:3-4:10-20.

[0011] Preferably, in S3, the mass ratio of granite aggregate, composite polyester resin, styrene, calcium carbonate, curing accelerator, diluent, plasticizer, curing agent, and quartz tailings is 60-85:20-30:1-10:20-60:1-2:0.2-1:0.2-1:0.5-5:10-20.

[0012] Preferably, in S3, the curing accelerator includes at least one of: cobalt isooctanoate, potassium isooctanoate, copper isooctanoate, cobalt naphthenate, potassium naphthenate, copper naphthenate, N,N-dimethylaniline, and N,N-diethylaniline.

[0013] Preferably, in S3, the curing agent includes at least one of methyl ethyl ketone peroxide, cyclohexanone peroxide, benzoyl peroxide, and tert-butyl peroxide.

[0014] Preferably, in S3, the plasticizer includes at least one of dibutyl phthalate, dioctyl phthalate, and tributyl phosphate.

[0015] Preferably, in S3, the diluent includes at least one of acetone, ethyl acetate, and phosphate ester.

[0016] Preferably, in S3, the bulk density of the quartz tailings is 1.2-1.5 g / cm³. 3 The particle size is 0.01-0.25 mm.

[0017] Preferably, in S3, the vibration frequency is 50-60Hz and the amplitude is 0.5-5mm.

[0018] A high-toughness flame-retardant polyester resin is prepared by the above-mentioned method for preparing high-toughness flame-retardant polyester resin. Beneficial effects

[0019] This invention combines polyacrylic acid with calcium chloride, and then adds sodium carbonate to react and generate calcium carbonate with polyacrylic acid on its surface. This not only effectively inhibits agglomeration, but also achieves high dispersion uniformity when compounded and ground with aluminum magnesium hydrotalcite and graphene oxide. Since aluminum magnesium hydrotalcite is a layered dihydroxy cluster mineral, and graphene oxide has a layered one-dimensional structure, graphene oxide, with the assistance of activated calcium carbonate, can be fully dispersed into the layered structure of aluminum magnesium hydrotalcite during the grinding process, resulting in extremely high bonding strength.

[0020] This invention uses aluminum-magnesium hydrotalcite and graphene oxide to coat activated calcium carbonate. This not only results in high bonding strength, but also ensures that the graphene oxide structure is fully dispersed and bonded into the aluminum-magnesium hydrotalcite structure during the grinding process. This leads to a large surface area, strong covering power, and excellent flame retardant properties in the resulting product. At the same time, it can be rapidly and uniformly dispersed in the resin to form a calcium carbonate-resin network structure, which greatly improves the interfacial strength and significantly enhances the strength and modulus of the product.

[0021] This invention uses granite aggregate and flame-retardant preform as a composite material, which is compounded with composite polyester resin. Because the polyacrylic acid structure contained in the flame-retardant preform can greatly improve its dispersion performance with the composite polyester resin, it effectively solves the problem of sedimentation and stratification that easily occurs during the mixing process. The synergistic effect effectively improves the efficiency and operability of the mixing process. The composite polyester resin can entangle with the molecular structure on the surface of the flame-retardant preform to form a whole. The polyester resin formed after curing has a high filler content and good mechanical properties of the product.

[0022] The polyester resin obtained by this invention has a density of 2.35-2.67 g / m³. 3 It has a compressive strength of up to 125MPa and a flexural strength of up to 44MPa. It also has excellent flame retardant properties and good dimensional stability, which can better meet the material performance requirements of artificial stone resin. Attached Figure Description

[0023] Figure 1The image shows a comparison of the compressive strength and flexural strength of the artificial quartz slabs prepared using the methods of Example 5 and Comparative Examples 1-2.

[0024] Figure 2 The graph shows a comparison of the impact resistance and linear thermal expansion coefficient of the artificial granite slabs prepared using the methods of Example 5 and Comparative Examples 1-2.

[0025] Figure 3 This is a comparison chart of the flame retardant properties of standard specimens prepared using the methods of Example 5 and Comparative Examples 1-2. Detailed Implementation

[0026] The present invention will be further explained below with reference to specific embodiments.

[0027] Example 1 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 1 kg of polyacrylic acid to 20 kg of 1 mol / L sodium hydroxide solution and stir until homogeneous. Adjust the temperature to 30°C, add 5 kg of calcium chloride and stir for 1 hour, then add 2 kg of sodium carbonate and stir for 10 hours. Centrifuge, wash, and vacuum dry. Add the polyacrylic acid to 5 kg of water, along with 1 kg of aluminum magnesium hydrotalcite and 1 kg of graphene oxide. Grind for 1 hour at a speed of 1000 r / min and a pressure of 1.2 MPa. Dry and pulverize to obtain the flame-retardant preform. S2. Under nitrogen protection, 6 kg of methyl ethylene glycol, 4 kg of 1,2-propanediol, and 10 kg of 1,4-butanediol are added to a reactor, followed by 8 kg of fumaric acid. The mixture is gradually heated to 205°C for polycondensation until the acid value drops to 15 mg KOH / g, yielding a prepolymer resin. The prepolymer resin is then cooled to 155°C, and 15 kg of phthalic anhydride, 4 kg of dehydrated malic anhydride, 3 kg of hydroquinone, and 10 kg of flame-retardant preform are added. The mixture is gradually heated to 200°C for polycondensation until the acid value reaches 6 mg KOH / g, yielding a composite polyester resin. S3. Mix 60kg of granite aggregate and 20kg of composite polyester resin evenly. Add 1kg of styrene, 20kg of calcium carbonate, and 1kg of cobalt isooctanoate and continue stirring for 1 hour at a stirring speed of 100r / min. Then add 0.2kg of acetone, 0.2kg of dibutyl phthalate, 0.5kg of methyl ethyl ketone peroxide, and 10kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 15 minutes at a frequency of 50Hz and an amplitude of 0.5mm. Cure at 30℃ for 10 hours, and after demolding, cure at room temperature for 1 hour to obtain high-toughness flame-retardant polyester resin.

[0028] Example 2 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 2 kg of polyacrylic acid to 30 kg of 2 mol / L sodium hydroxide solution and stir until homogeneous. Adjust the temperature to 40℃, add 10 kg of calcium chloride and stir for 2 h, add 6 kg of sodium carbonate and stir for 20 h, centrifuge, wash, vacuum dry, add to 15 kg of water, add 2 kg of aluminum magnesium hydrotalcite and 3 kg of graphene oxide, grind for 2 h at a grinding speed of 5000 r / min and a grinding pressure of 3.5 MPa, dry, and pulverize to obtain flame-retardant preform. S2. Under nitrogen protection, 10 kg of methyl ethylene glycol, 8 kg of 1,2-propanediol, and 16 kg of 1,4-butanediol were added to a reactor, followed by the addition of 16 kg of fumaric acid. The mixture was gradually heated to 215°C for polycondensation until the acid value dropped to 25 mg KOH / g, yielding a prepolymer resin. The prepolymer resin was then cooled to 165°C, and 23 kg of phthalic anhydride, 9 kg of dehydrated malic anhydride, 4 kg of hydroquinone, and 20 kg of flame-retardant preform were added. The mixture was gradually heated to 210°C for polycondensation until the acid value reached 12 mg KOH / g, yielding a composite polyester resin. S3. Mix 85kg of granite aggregate and 30kg of composite polyester resin evenly. Add 10kg of styrene, 60kg of calcium carbonate, and 2kg of N,N-dimethylaniline and continue stirring for 2 hours at a stirring speed of 200r / min. Then add 1kg of phosphate ester, 1kg of dibutyl phthalate, 5kg of cyclohexanone peroxide, and 10kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 60 minutes at a vibration frequency of 60Hz and an amplitude of 5mm. Cure at 50℃ for 20 hours, and after demolding, cure at room temperature for 5 hours to obtain high-toughness flame-retardant polyester resin.

[0029] Example 3 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 1.7 kg of polyacrylic acid to 22 kg of 1.8 mol / L sodium hydroxide solution and stir until homogeneous. Adjust the temperature to 33℃, add 8 kg of calcium chloride and stir for 80 min, add 5 kg of sodium carbonate and stir for 12 h, centrifuge, wash, vacuum dry, add to 12 kg of water, add 1.2 kg of aluminum magnesium hydrotalcite and 2.5 kg of graphene oxide, grind for 80 min at a grinding speed of 4000 r / min and a grinding pressure of 2 MPa, dry, and pulverize to obtain flame-retardant preform. S2. Under nitrogen protection, 7 kg of methyl ethylene glycol, 7 kg of 1,2-propanediol, and 12 kg of 1,4-butanediol were added to a reactor, followed by the addition of 14 kg of fumaric acid. The mixture was gradually heated to 208°C for polycondensation until the acid value dropped to 22 mg KOH / g, yielding a prepolymer resin. The prepolymer resin was then cooled to 158°C, and 21 kg of phthalic anhydride, 5 kg of dehydrated malic anhydride, 3.7 kg of hydroquinone, and 12 kg of flame-retardant preform were added. The mixture was gradually heated to 208°C for polycondensation until the acid value reached 8 mg KOH / g, yielding a composite polyester resin. S3. Mix 68kg of granite aggregate and 28kg of composite polyester resin evenly. Add 3kg of styrene, 50kg of calcium carbonate, and 1.2kg of copper isooctanoate and continue stirring for 100min at a stirring speed of 120r / min. Then add 0.8kg of acetone, 0.4kg of dioctyl phthalate, 4kg of benzoyl peroxide, and 8kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 30min at a frequency of 58Hz and an amplitude of 1mm. Cure at 45℃ for 12h, and after demolding, cure at room temperature for 4h to obtain high-toughness flame-retardant polyester resin.

[0030] Example 4 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 1.3 kg of polyacrylic acid to 28 kg of 1.2 mol / L sodium hydroxide solution and stir until homogeneous. Adjust the temperature to 37°C, add 6 kg of calcium chloride and stir for 100 min, add 3 kg of sodium carbonate and stir for 18 h, centrifuge, wash, vacuum dry, add to 8 kg of water, add 1.8 kg of aluminum magnesium hydrotalcite and 1.5 kg of graphene oxide, grind for 100 min at a grinding speed of 2000 r / min and a grinding pressure of 2.8 MPa, dry, and pulverize to obtain flame-retardant preform. S2. Under nitrogen protection, 9 kg of methyl ethylene glycol, 5 kg of 1,2-propanediol, and 14 kg of 1,4-butanediol were added to a reactor, followed by the addition of 10 kg of fumaric acid. The mixture was gradually heated to 212 °C for polycondensation until the acid value dropped to 18 mg KOH / g, yielding a prepolymer resin. The prepolymer resin was then cooled to 162 °C, and 17 kg of phthalic anhydride, 7 kg of dehydrated malic anhydride, 3.3 kg of hydroquinone, and 18 kg of flame-retardant preform were added. The mixture was gradually heated to 202 °C for polycondensation until the acid value reached 10 mg KOH / g, yielding a composite polyester resin. S3. Mix 77kg of granite aggregate and 22kg of composite polyester resin evenly. Add 7kg of styrene, 30kg of calcium carbonate, and 1.8kg of N,N-diethylaniline and continue stirring for 80 minutes at a stirring speed of 180r / min. Then add 0.4kg of phosphate ester, 0.8kg of dioctyl phthalate, 2kg of tert-butyl peroxide, and 2kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 50 minutes at a frequency of 52Hz and an amplitude of 3mm. Cure at 35℃ for 18 hours and then at room temperature for 2 hours after demolding to obtain high-toughness flame-retardant polyester resin.

[0031] Example 5 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 1.5 kg of polyacrylic acid to 25 kg of 1.5 mol / L sodium hydroxide solution and stir until homogeneous. Adjust the temperature to 35°C, add 7 kg of calcium chloride and stir for 90 min, add 4 kg of sodium carbonate and stir for 15 h, centrifuge, wash, vacuum dry, add to 10 kg of water, add 1.5 kg of aluminum magnesium hydrotalcite and 2 kg of graphene oxide, grind for 90 min at a grinding speed of 3000 r / min and a grinding pressure of 2.4 MPa, dry, and pulverize to obtain flame-retardant preform. S2. Under nitrogen protection, 8 kg of methyl ethylene glycol, 6 kg of 1,2-propanediol, and 13 kg of 1,4-butanediol were added to a reactor, followed by the addition of 12 kg of fumaric acid. The mixture was gradually heated to 210 °C for polycondensation until the acid value dropped to 20 mg KOH / g, yielding a prepolymer resin. The prepolymer resin was then cooled to 160 °C, and 19 kg of phthalic anhydride, 6 kg of dehydrated malic anhydride, 3.5 kg of hydroquinone, and 15 kg of flame-retardant preform were added. The mixture was gradually heated to 205 °C for polycondensation until the acid value reached 9 mg KOH / g, yielding a composite polyester resin. S3. Mix 72kg of granite aggregate and 25kg of composite polyester resin evenly. Add 5kg of styrene, 40kg of calcium carbonate, and 1.5kg of cobalt naphthenate and continue stirring for 90 minutes at a stirring speed of 150r / min. Then add 0.6kg of ethyl acetate, 0.6kg of tributyl phosphate, 3kg of benzoyl peroxide, and 5kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 40 minutes at a vibration frequency of 55Hz and an amplitude of 2mm. Cure at 40℃ for 15 hours and then at room temperature for 3 hours after demolding to obtain high-toughness flame-retardant polyester resin.

[0032] Comparative Example 1 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 1.5 kg of polyacrylic acid to 25 kg of 1.5 mol / L sodium hydroxide solution and stir until homogeneous. Adjust the temperature to 35°C, add 7 kg of calcium chloride and stir for 90 min, add 4 kg of sodium carbonate and stir for 15 h, centrifuge, wash, vacuum dry, add to 10 kg of water, add 1.5 kg of aluminum magnesium hydrotalcite and grind for 90 min at a grinding speed of 3000 r / min and a grinding pressure of 2.4 MPa, dry, and pulverize to obtain flame-retardant preform. S2. Under nitrogen protection, 8 kg of methyl ethylene glycol, 6 kg of 1,2-propanediol, and 13 kg of 1,4-butanediol were added to a reactor, followed by the addition of 12 kg of fumaric acid. The mixture was gradually heated to 210 °C for polycondensation until the acid value dropped to 20 mg KOH / g, yielding a prepolymer resin. The prepolymer resin was then cooled to 160 °C, and 19 kg of phthalic anhydride, 6 kg of dehydrated malic anhydride, 3.5 kg of hydroquinone, and 15 kg of flame-retardant preform were added. The mixture was gradually heated to 205 °C for polycondensation until the acid value reached 9 mg KOH / g, yielding a composite polyester resin. S3. Mix 72kg of granite aggregate and 25kg of composite polyester resin evenly. Add 5kg of styrene, 40kg of calcium carbonate, and 1.5kg of cobalt naphthenate and continue stirring for 90 minutes at a stirring speed of 150r / min. Then add 0.6kg of ethyl acetate, 0.6kg of tributyl phosphate, 3kg of benzoyl peroxide, and 5kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 40 minutes at a vibration frequency of 55Hz and an amplitude of 2mm. Cure at 40℃ for 15 hours and then at room temperature for 3 hours after demolding to obtain high-toughness flame-retardant polyester resin.

[0033] Comparative Example 2 A method for preparing a high-toughness flame-retardant polyester resin includes the following steps: S1. Add 7 kg of calcium chloride to 25 kg of 1.5 mol / L sodium hydroxide solution and stir until homogeneous. Add 4 kg of sodium carbonate and stir for 15 h. Centrifuge, wash, vacuum dry, add to 10 kg of water, add 1.5 kg of aluminum magnesium hydrotalcite and 2 kg of graphene oxide, grind for 90 min at a grinding speed of 3000 r / min and a grinding pressure of 2.4 MPa, dry, and pulverize to obtain flame-retardant preform. S2. Under nitrogen protection, 8 kg of methyl ethylene glycol, 6 kg of 1,2-propanediol, and 13 kg of 1,4-butanediol were added to a reactor, followed by the addition of 12 kg of fumaric acid. The mixture was gradually heated to 210 °C for polycondensation until the acid value dropped to 20 mg KOH / g, yielding a prepolymer resin. The prepolymer resin was then cooled to 160 °C, and 19 kg of phthalic anhydride, 6 kg of dehydrated malic anhydride, 3.5 kg of hydroquinone, and 15 kg of flame-retardant preform were added. The mixture was gradually heated to 205 °C for polycondensation until the acid value reached 9 mg KOH / g, yielding a composite polyester resin. S3. Mix 72kg of granite aggregate and 25kg of composite polyester resin evenly. Add 5kg of styrene, 40kg of calcium carbonate, and 1.5kg of cobalt naphthenate and continue stirring for 90 minutes at a stirring speed of 150r / min. Then add 0.6kg of ethyl acetate, 0.6kg of tributyl phosphate, 3kg of benzoyl peroxide, and 5kg of quartz tailings and mix evenly. Pour the mixture into a mold and vibrate for 40 minutes at a vibration frequency of 55Hz and an amplitude of 2mm. Cure at 40℃ for 15 hours and then at room temperature for 3 hours after demolding to obtain high-toughness flame-retardant polyester resin.

[0034] Artificial engineered stone slabs were prepared using the methods of Example 5 and Comparative Examples 1-2. Since the size of the flame-retardant precast material, calcium carbonate, and quartz tailings in Example 5 and Comparative Examples 1-2 was less than 6 mm, the physical properties of the obtained artificial engineered stone were measured with reference to the fine aggregate engineered stone slabs in GB / T 35157-2017 "Resin-type Synthetic Stone Slabs".

[0035] like Figure 1 and Figure 2 As shown, the artificial quartz slabs prepared using Example 5 have better compressive strength and flexural strength, as well as good impact resistance, low linear thermal expansion coefficient, and good dimensional stability.

[0036] The applicant believes that this invention utilizes aluminum-magnesium hydrotalcite and graphene oxide to coat activated calcium carbonate, enabling rapid and uniform dispersion in the resin to form a calcium carbonate-resin network structure. This significantly improves interfacial strength and substantially enhances the strength and modulus of the product. Furthermore, the use of granite aggregate and flame-retardant preforms as a composite material, combined with composite polyester resin, allows the polyacrylic acid structure in the flame-retardant preforms to greatly improve its dispersion performance with the composite polyester resin. The composite polyester resin can then entangle with the molecular structure on the surface of the flame-retardant preforms to form a unified whole. After curing, the resulting polyester resin, with a significantly increased polyester resin filler content, results in excellent mechanical properties in the product.

[0037] Standard specimens were prepared using the methods of Example 5 and Comparative Examples 1-2, and their flame-retardant properties were tested. Their limiting oxygen index is as follows: Figure 3As shown, the sample obtained in Example 5 exhibits the best flame-retardant properties. The applicant believes this is because, on the one hand, the present invention uses a composite of aluminum-magnesium hydrotalcite and graphene oxide to coat activated calcium carbonate. During the grinding process, the graphene oxide structure is fully dispersed into the aluminum-magnesium hydrotalcite structure and bonded together, resulting in a product with a large surface area, strong covering power, and excellent flame-retardant properties. On the other hand, the flame-retardant preform can be uniformly dispersed in the resin, effectively further enhancing the flame-retardant properties.

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-toughness flame-retardant polyester resin, characterized in that, Includes the following steps: S1. Add polyacrylic acid to sodium hydroxide solution and stir evenly. Adjust the temperature to 30-40℃, add calcium chloride and stir for 1-2 hours, add sodium carbonate and stir for 10-20 hours, centrifuge, wash, and vacuum dry; then add to water, add aluminum magnesium hydrotalcite and graphene oxide, grind for 1-2 hours, dry, and pulverize to obtain flame retardant preform. S2. Under nitrogen protection, methyl ethylene glycol, 1,2-propanediol, and 1,4-butanediol are added to a reactor, followed by the addition of fumaric acid. The mixture is gradually heated to 205-215℃ for polycondensation until the acid value drops to 15-25 mg KOH / g, yielding a prepolymer resin. The prepolymer resin is then cooled to 155-165℃, and phthalic anhydride, dehydrated malic anhydride, hydroquinone, and flame-retardant preform are added. The mixture is gradually heated to 200-210℃ for polycondensation until the acid value reaches 6-12 mg KOH / g, yielding a composite polyester resin. S3. Mix granite aggregate and composite polyester resin evenly, add styrene, calcium carbonate and curing accelerator and continue stirring for 1-2 hours. Then add diluent, plasticizer, curing agent and quartz tailings and mix evenly. Pour into mold and vibrate for 15-60 minutes. Cure at 30-50℃ for 10-20 hours. After demolding, cure at room temperature for 1-5 hours to obtain high toughness flame retardant polyester resin.

2. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S1, the mass ratio of polyacrylic acid, calcium chloride, sodium carbonate, aluminum magnesium hydrotalcite, and graphene oxide is 1-2:5-10:2-6:1-2:1-3.

3. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S1, the grinding pressure is 1.2-3.5 MPa and the grinding speed is 1000-5000 r / min.

4. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S2, the mass ratio of methyl ethylene glycol, 1,2-propanediol, 1,4-butanediol, trans-butenedioic acid, phthalic anhydride, dehydrated malic anhydride, hydroquinone, and flame-retardant preform is 6-10:4-8:10-16:8-16:15-23:4-9:3-4:10-20.

5. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S3, the mass ratio of granite aggregate, composite polyester resin, styrene, calcium carbonate, curing accelerator, diluent, plasticizer, curing agent, and quartz tailings is 60-85:20-30:1-10:20-60:1-2:0.2-1:0.2-1:0.5-5:10-20.

6. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S3, the curing accelerator includes at least one of the following: cobalt isooctanoate, potassium isooctanoate, copper isooctanoate, cobalt naphthenate, potassium naphthenate, copper naphthenate, N,N-dimethylaniline, and N,N-diethylaniline.

7. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S3, the curing agent includes at least one of methyl ethyl ketone peroxide, cyclohexanone peroxide, benzoyl peroxide, and tert-butyl peroxide.

8. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S3, the plasticizer includes at least one of dibutyl phthalate, dioctyl phthalate, and tributyl phosphate.

9. The method for preparing the high-toughness flame-retardant polyester resin according to claim 1, characterized in that, In S3, the vibration frequency is 50-60Hz and the amplitude is 0.5-5mm.

10. A high-toughness flame-retardant polyester resin, characterized in that, It is prepared by the method of any one of claims 1-9 for the preparation of high-toughness flame-retardant polyester resin.

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