High-temperature-resistant and strong-acid-and-strong-base-resistant unsaturated resin composition and preparation method thereof

Abstract

The present application belongs to the technical field of unsaturated polyester resin composition, and particularly relates to a high-temperature-resistant and strong-acid-and-strong-alkali-resistant unsaturated resin composition and a preparation method thereof.The preparation method of the high-temperature-resistant and strong-acid-and-strong-alkali-resistant unsaturated resin composition comprises the following steps: S1, first, melamine and polyformaldehyde are mixed to prepare a prepolymer, then the prepolymer is added with hydroxyethyl acrylate for stirring reaction to obtain an unsaturated polyester; S2, the unsaturated polyester, a filler, ethylene glycol dimethacrylate, vinyl polysiloxane, a silane coupling agent, benzoyl peroxide and an organic solvent in step S1 are put into a mixing tank, and are mixed by high-speed stirring at room temperature to obtain the high-temperature-resistant and strong-acid-and-strong-alkali-resistant unsaturated resin composition.The present application takes the unsaturated polyester as a basis and cooperates with other functional materials, so that the material not only has good flame retardancy and thermal stability, but also significantly improves the resistance in a strong acid environment and a strong alkali environment.

Description

Technical Field

[0001] This invention belongs to the technical field of unsaturated polyester resin compositions, specifically relating to a high-temperature resistant and strong acid and alkali resistant unsaturated resin composition and its preparation method. Background Technology

[0002] Unsaturated polyester (UPR) is one of the three major types of thermosetting resins in my country, ranking alongside epoxy resin and phenolic resin as a pillar material of the industry. Compared to the latter two, UPR exhibits wider adoption and greater development vitality in industrial applications. Its core advantages can be attributed to multiple characteristics such as good cost control, outstanding processing adaptability, balanced comprehensive mechanical properties, and excellent resistance to chemical media, making it unique among many resin matrices. In practical applications, unsaturated polyester has deeply penetrated many sectors of the national economy: In glass fiber reinforced composites, it serves as a matrix resin that works synergistically with glass fiber to form fiberglass reinforced plastic (FRP) materials, which are widely used in large structural components such as storage tanks, pipelines, and cooling towers; In the coatings and adhesives industry, UPR imparts excellent adhesion and weather resistance to coatings, making it suitable for anti-corrosion coatings, flooring materials, and bonding systems; In the artificial stone industry, it can simulate the texture of natural stone and possesses good processability and surface gloss; In automobile manufacturing, UPR is used in lightweight components such as body panels and bumpers, contributing to energy conservation and emission reduction; In the new energy field, as one of the key structural materials for wind turbine blades, it undertakes the performance requirements of fatigue resistance, weather resistance, and lightweight high strength.

[0003] Unsaturated polyesters, with their unique molecular structure, endow the material with a series of excellent properties, making them occupy an important position among many resin systems. Their main advantages can be summarized as follows: (1) Excellent processing performance: The unsaturated polyester molecular chain contains a large number of unsaturated double bonds, which gives it strong cross-linking reactivity, significantly reducing the difficulty of molding process and improving production efficiency. (2) Good mechanical properties: After curing, the unsaturated polyester molecular chain cross-links to form a dense three-dimensional network structure, giving the material high hardness, strength, as well as good wear resistance and impact resistance, meeting the application requirements of various structural parts, and suitable for use in harsh environments such as chemical equipment and pipelines.

[0004] Chinese Patent (Announcement No. CN106633586B) discloses a halogen-free and phosphorus-free flame-retardant unsaturated polyester resin composition and its uses. This invention comprises 60-80 parts by weight of halogen-free and phosphorus-free unsaturated polyester resin, 20-40 parts by weight of benzoxazine resin, 35-50 parts by weight of diluent, 80-110 parts by weight of inorganic filler, 1-3 parts by weight of initiator, 2-4 parts by weight of curing agent, 5-15 parts by weight of low-shrinkage agent, and 5-10 parts by weight of release agent. After hot pressing, the unsaturated polyester resin composition improves the normal and hot mechanical properties of the product through the excellent properties of the benzoxazine resin itself. However, this patented technology requires the addition of benzoxazine resin and a corresponding curing agent to achieve excellent flame-retardant properties, and also lacks research on its high-temperature resistance and resistance to strong acids and alkalis.

[0005] Therefore, there is an urgent need for an unsaturated resin composition that, without using benzoxazine resin, is based on unsaturated polyester and combined with other functional materials, which can ensure that the material has good flame retardancy and thermal stability, and can significantly improve its resistance to strong acid and strong alkali environments. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition and its preparation method. The invention first mixes melamine and paraformaldehyde to obtain a prepolymer. Then, hydroxyethyl acrylate is added to the prepolymer and stirred to obtain an unsaturated polyester. Next, the unsaturated polyester, filler, ethylene glycol dimethacrylate, vinyl polysiloxane, silane coupling agent, benzoyl peroxide, and organic solvent are added to a mixing tank and stirred at high speed at room temperature to obtain a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition. Through the synergistic effect of the components, the present invention prepares a resin composition with good heat resistance and flame retardancy without using benzoxazine resin, and improves the material's resistance to strong acids and alkalis.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides a method for preparing an unsaturated resin composition resistant to high temperatures and strong acids and alkalis, comprising the following steps: S1. First, melamine and paraformaldehyde are mixed to prepare a prepolymer. Then, hydroxyethyl acrylate is added to the prepolymer and stirred to react, resulting in an unsaturated polyester. S2. The unsaturated polyester, filler, ethylene glycol dimethacrylate, vinyl polysiloxane, silane coupling agent, benzoyl peroxide and organic solvent described in step S1 are added to a mixing tank and mixed at room temperature and high speed to obtain an unsaturated resin composition that is resistant to high temperature and strong acids and alkalis.

[0008] As a preferred technical solution of the present invention, the conditions for high-speed stirring and mixing in step S2 are: stirring speed of 800~900 r / min and stirring time of 20~30 min.

[0009] As a preferred embodiment of the present invention, the components in step S2 include, by weight, 80-90 parts of unsaturated polyester, 20-30 parts of filler, 10-20 parts of ethylene glycol dimethacrylate, 5-10 parts of vinyl polysiloxane, 1-2 parts of silane coupling agent, 1-2 parts of benzoyl peroxide, and 180-200 parts of organic solvent.

[0010] As a preferred embodiment of the present invention, the unsaturated polyester may be in the following weight proportions: 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, or 90 parts, etc.

[0011] As a preferred embodiment of the present invention, the weight fraction of the filler may be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, etc.

[0012] As a preferred embodiment of the present invention, the weight parts of the ethylene glycol dimethacrylate may be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, or 20 parts, etc.

[0013] As a preferred embodiment of the present invention, the vinyl polysiloxane may be expressed in parts by weight of 5, 6, 7, 8, 9, or 10, etc.

[0014] As a preferred embodiment of the present invention, the weight parts of the silane coupling agent may be 1.0 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2.0 parts, etc.

[0015] As a preferred embodiment of the present invention, the weight parts of benzoyl peroxide may be 1.0 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2.0 parts, etc.

[0016] As a preferred embodiment of the present invention, the organic solvent may be in the following weight proportions: 180 parts, 190 parts, or 200 parts, etc.

[0017] As a preferred technical solution of the present invention, the preparation steps of the prepolymer are as follows: by weight, 120-130 parts of paraformaldehyde and 150-160 parts of methanol are added to a reaction vessel and mixed evenly, the pH is adjusted to 8.5-9.0 and the temperature is raised to 55-60℃ for 60-80 min, then 110-112 parts of melamine are added and the temperature is raised to 80-85℃ for 2-4 h to obtain the prepolymer.

[0018] As a preferred embodiment of the present invention, the stirring reaction step is as follows: by weight, 230-240 parts of the prepolymer are adjusted to pH 2-3 at 40-45°C, then 80-100 parts of hydroxyethyl acrylate, 2-4 parts of boric acid aqueous solution and 0.4-0.6 parts of hydroquinone are added and reacted at a constant temperature for 4-6 hours. The pH is adjusted to 6.5-7.0, methanol is removed by vacuum, the mixture is filtered, washed with petroleum ether, and dried under vacuum to obtain unsaturated polyester.

[0019] This invention first uses melamine and paraformaldehyde as raw materials. Melamine and paraformaldehyde undergo a hydroxymethylation reaction under weakly alkaline conditions to generate a polyhydroxymethyl melamine prepolymer. Then, hydroxyethyl acrylate is added, and the hydroxyl groups of hydroxyethyl acrylate and the hydroxymethyl groups on the prepolymer undergo etherification to finally obtain an unsaturated polyester containing a triazine ring.

[0020] As a preferred embodiment of the present invention, the filler is selected from one or more of magnesium hydroxide, aluminum hydroxide, calcium carbonate, silicon dioxide, and aluminum oxide.

[0021] As a preferred embodiment of the present invention, the filler is magnesium hydroxide and silicon dioxide.

[0022] As a preferred embodiment of the present invention, the mass ratio of magnesium hydroxide to silicon dioxide is (1~2):1.

[0023] As a preferred embodiment of the present invention, the magnesium hydroxide is vinyl-modified magnesium hydroxide with a whiteness of 92-95% and D. 50 The particle size is 2~3μm, and the moisture content is 0.2~0.5%.

[0024] As a preferred embodiment of the present invention, the silica is siloxane-treated fumed silica with a specific surface area of ​​80~150m² / g, a drying loss of 0.2~0.5%, and a pH value of 4.5~6.5.

[0025] The filler of this invention is selected from magnesium hydroxide, aluminum hydroxide, calcium carbonate, silicon dioxide, and alumina. It is preferred to use vinyl-modified magnesium hydroxide and siloxane-treated fumed silica in combination. By controlling the amount of both, a good synergistic effect is achieved, which significantly improves the overall performance of the unsaturated resin composition, thereby achieving the goal of high temperature resistance and strong acid and alkali resistance.

[0026] As a preferred embodiment of the present invention, the vinyl polysiloxane is a fluorinated vinyl branched polysiloxane; the fluorinated vinyl branched polysiloxane is prepared from methyltrimethoxysilane, vinyltrimethoxysilane and 3,3,3-trifluoropropyltrimethoxysilane as raw materials.

[0027] As a preferred technical solution of the present invention, the preparation steps of the fluorinated vinyl branched polysiloxane are as follows: by weight, 160-180 parts of anhydrous ethanol and 20-40 parts of deionized water are mixed, then 60-70 parts of methyltrimethoxysilane are added and the pH is adjusted to 4-5 and stirred for 2-4 hours, then 20-30 parts of vinyltrimethoxysilane and 5-10 parts of 3,3,3-trifluoropropyltrimethoxysilane are added, the temperature is raised to 60-70°C and reacted for 4-6 hours, after the reaction is completed, the mixture is cooled to room temperature, rotary evaporated, washed with deionized water, and vacuum dried to obtain the fluorinated vinyl branched polysiloxane.

[0028] This invention uses methyltrimethoxysilane, vinyltrimethoxysilane, and fluorinated silane as raw materials. In an acidic water / ethanol system, the methoxy group of methyltrimethoxysilane hydrolyzes to generate silanol groups. Vinyltrimethoxysilane is added and reacts with the silanol groups of methyltrimethoxysilane to form stable Si-O-Si bonds. Moreover, both are trifunctional monomers that can synergistically construct a branched framework. In conjunction with fluorinated silane, fluorine is introduced into the side chain of polysiloxane, and finally, fluorinated vinyl branched polysiloxane is obtained.

[0029] As a preferred embodiment of the present invention, the silane coupling agent is selected from one or more of silane coupling agents KH-151, KH-171, and KH-172.

[0030] As a preferred embodiment of the present invention, the organic solvent is selected from one or more of butanone, chloroform, and tetrahydrofuran.

[0031] A second aspect of the present invention provides an unsaturated resin composition that is resistant to high temperatures and strong acids and alkalis, prepared by the method described in the first aspect.

[0032] Compared with the prior art, the beneficial effects of the present invention are: (1) The unsaturated polyester of the present invention introduces triazine rings during the preparation process. The rigid triazine rings provide intrinsic molecular thermal stability and chemical inertness, and improve the crosslinking density and heat resistance of the system. During combustion, the triazine rings promote the formation of a dense nitrogen-rich carbon layer and release inert gas, achieving a good flame retardant effect. The dense crosslinking network and the chemical inertness of the triazine rings work together to block the penetration of acid and alkali media, effectively improving the acid and alkali resistance of the material.

[0033] (2) The composite filler of the present invention is composed of vinyl-modified magnesium hydroxide and siloxane-surface-treated fumed silica. The vinyl double bonds on the surface of the former and the siloxane segments of the latter can interact with unsaturated polyester and vinyl polysiloxane, thereby constructing an organic-inorganic covalent hybrid network to restrict the thermal motion of polymer chains at high temperatures and significantly improve the heat resistance of the material. Under combustion conditions, magnesium hydroxide decomposes and absorbs heat when heated, and the siloxane component burns to form a dense siloxane ceramic layer. The two construct a composite inorganic barrier layer to inhibit the spread of combustion and achieve a good flame retardant effect. At the same time, the dense hybrid crosslinking network extends the penetration path of acid and alkali media, and the covalent anchoring of siloxane segments avoids the rapid dissolution of acid and alkali media and the generation of defects, ensuring that the material has good resistance to strong acids and alkalis.

[0034] (3) The fluorinated vinyl branched polysiloxane of the present invention covalently introduces Si-O-Si inorganic branched segments and fluorinated side groups by means of the double bond combination of vinyl and unsaturated polyester. The branched topology can restrict the thermal motion of resin segments and improve the heat resistance of the material. During combustion, silicon-fluorine synergy promotes the formation of a dense silicon-rich carbon layer and plays a role in enhancing the flame retardant effect through the synergistic effect of condensed phase. The excellent chemical inertness of the polysiloxane network itself, together with the hydrophobic barrier constructed by the fluorine groups, extends the diffusion path of the corrosive medium, thereby obtaining excellent resistance to strong acids and alkalis. Attached Figure Description

[0035] Figure 1 The images show the FTIR spectra of the fluorinated vinyl branched polysiloxane and the ordinary vinyl polysiloxane in Example 1. Detailed Implementation

[0036] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0037] The sources of some components in the examples and comparative examples are as follows: Ordinary unsaturated polyester resin, model Aropol L 80305 A, purchased from INEOS. Melamine, CAS No. 108-78-1, purchased from Sinopharm Chemical Reagent Co., Ltd. Paraformaldehyde, CAS No. 30525-89-4, purchased from Sinopharm Chemical Reagent Co., Ltd. Hydroxyethyl acrylate, product number H104535, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Stannous octanoate, CAS No. 301-10-0, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Vinyl modified magnesium hydroxide, model HY-MH-V1, whiteness 93%, D 50The particle size was 2.5 μm and the moisture content was 0.4%. It was purchased from Guangdong Haike New Materials Technology Co., Ltd. Ordinary magnesium hydroxide, product number M767093, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Siloxane-treated fumed silica, model HD171, with a specific surface area of ​​90 m² / g, a drying loss of 0.3%, and a pH value of 5.5, was purchased from Shandong Hongruitong New Material Technology Co., Ltd. Ordinary fumed silica, item number S697170, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Ethylene glycol dimethacrylate, product number E106223, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Methyltrimethoxysilane, product number T106658, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Vinyltrimethoxysilane, product number V162969, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. 3,3,3-Trifluoropropyltrimethoxysilane, product number T162296, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Ordinary vinyl polysiloxane, product number V304361, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Silane coupling agent KH-151 was purchased from Nanjing Jingtianwei Chemical Co., Ltd. Silane coupling agent KH-171 was purchased from Nanjing Jingtianwei Chemical Co., Ltd. Silane coupling agent KH-172 was purchased from Nanjing Jingtianwei Chemical Co., Ltd. Benzoyl peroxide, CAS No. 94-36-0, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Example 1

[0038] This embodiment provides a method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition, comprising the following steps: S1. By weight, 130 parts of paraformaldehyde and 160 parts of methanol were added to a reaction vessel and mixed evenly. The pH was adjusted to 9.0 and the temperature was raised to 60℃ for 60 min. Then, 112 parts of melamine were added and the temperature was raised to 85℃ for 2 h to obtain a prepolymer. The pH of 240 parts of the prepolymer was adjusted to 3 at 45℃. Then, 100 parts of hydroxyethyl acrylate, 4 parts of boric acid aqueous solution and 0.6 parts of hydroquinone were added and the mixture was kept at the temperature for 6 h. The pH was adjusted to 7.0. The methanol was removed by vacuum, filtered, washed with petroleum ether, and dried under vacuum to obtain an unsaturated polyester.

[0039] S2. Add the 90 parts of unsaturated polyester, 30 parts of filler (20 parts of vinyl-modified magnesium hydroxide and 10 parts of siloxane-treated fumed silica), 20 parts of ethylene glycol dimethacrylate, 10 parts of vinyl polysiloxane, 2 parts of alkane coupling agent KH-151, 2 parts of benzoyl peroxide, and 200 parts of organic solvent methyl ethyl ketone to a mixing tank, and stir at a high speed of 900 r / min for 20 min at room temperature to obtain an unsaturated resin composition that is resistant to high temperature and strong acids and alkalis.

[0040] Preparation of the fluorinated vinyl branched polysiloxane: 180 parts by weight of anhydrous ethanol and 20 parts by weight of deionized water were mixed, then 70 parts by weight of methyltrimethoxysilane were added and the pH was adjusted to 5 and stirred for 4 hours. Then 30 parts by weight of vinyltrimethoxysilane and 510 parts by weight of 3,3,3-trifluoropropyltrimethoxysilane were added, and the mixture was heated to 70°C and reacted for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, rotary evaporated, washed with deionized water, and dried under vacuum to obtain the fluorinated vinyl branched polysiloxane. Example 2

[0041] This embodiment provides a method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition, comprising the following steps: S1. By weight, 120 parts of paraformaldehyde and 150 parts of methanol were added to a reaction vessel and mixed evenly. The pH was adjusted to 8.5 and the temperature was raised to 55°C and reacted for 80 min. Then, 110 parts of melamine were added and the temperature was raised to 80°C and reacted for 4 h to obtain a prepolymer. The pH of 240 parts of the prepolymer was adjusted to 2 at 40°C. Then, 80 parts of hydroxyethyl acrylate, 2 parts of boric acid aqueous solution and 0.4 parts of hydroquinone were added and reacted at the temperature for 4 h. The pH was adjusted to 6.5, methanol was removed by vacuum, filtered, washed with petroleum ether, and dried under vacuum to obtain an unsaturated polyester.

[0042] S2. Add the 80 parts of unsaturated polyester, 20 parts of filler (10 parts of vinyl-modified magnesium hydroxide and 10 parts of siloxane-treated fumed silica), 10 parts of ethylene glycol dimethacrylate, 5 parts of vinyl polysiloxane, 1 part of silane coupling agent KH-171, 1 part of benzoyl peroxide, and 180 parts of organic solvent chloroform to a mixing tank, and stir at high speed at 800 r / min for 30 min at room temperature to obtain an unsaturated resin composition that is resistant to high temperature and strong acids and alkalis.

[0043] Preparation of the fluorinated vinyl branched polysiloxane: 160 parts by weight of anhydrous ethanol and 40 parts by weight of deionized water were mixed, then 60 parts by weight of methyltrimethoxysilane were added and the pH was adjusted to 4 and stirred for 2 hours. Then 20 parts by weight of vinyltrimethoxysilane and 5 parts by weight of 3,3,3-trifluoropropyltrimethoxysilane were added, and the mixture was heated to 60°C and reacted for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, rotary evaporated, washed with deionized water, and vacuum dried to obtain the fluorinated vinyl branched polysiloxane. Example 3

[0044] This embodiment provides a method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition, comprising the following steps: S1. By weight, 124 parts of paraformaldehyde and 156 parts of methanol were added to a reactor and mixed evenly. The pH was adjusted to 8.8 and the temperature was raised to 57°C and reacted for 70 min. Then, 111 parts of melamine were added and the temperature was raised to 82°C and reacted for 3 h to obtain a prepolymer. The pH of 234 parts of the prepolymer was adjusted to 2.5 at 42°C. Then, 90 parts of hydroxyethyl acrylate, 3 parts of boric acid aqueous solution and 0.5 parts of hydroquinone were added and reacted at the temperature for 5 h. The pH was adjusted to 6.8. The methanol was removed by vacuum, filtered, washed with petroleum ether, and dried under vacuum to obtain an unsaturated polyester.

[0045] S2. Add the 88 parts of unsaturated polyester, 25 parts of filler (15 parts of vinyl-modified magnesium hydroxide and 10 parts of siloxane-treated fumed silica), 14 parts of ethylene glycol dimethacrylate, 8 parts of vinyl polysiloxane, 1.4 parts of silane coupling agent KH-172, 1.4 parts of benzoyl peroxide, and 190 parts of organic solvent tetrahydrofuran to a mixing tank, and mix at high speed at 850 r / min for 24 min at room temperature to obtain an unsaturated resin composition that is resistant to high temperature and strong acids and alkalis.

[0046] Preparation of the fluorinated vinyl branched polysiloxane: 170 parts by weight of anhydrous ethanol and 30 parts by weight of deionized water were mixed, then 65 parts by weight of methyltrimethoxysilane were added and the pH was adjusted to 4.5 and stirred for 3 hours. Then 24 parts by weight of vinyltrimethoxysilane and 8 parts by weight of 3,3,3-trifluoropropyltrimethoxysilane were added, and the mixture was heated to 65°C and reacted for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, rotary evaporated, washed with deionized water, and dried under vacuum to obtain the fluorinated vinyl branched polysiloxane.

[0047] Comparative Example 1 The difference between this comparative example and Example 1 is that a common unsaturated polyester resin (model Aropol L 80305A) was used instead of the unsaturated polyester prepared by the technical solution of the present invention.

[0048] Comparative Example 2 The difference between this comparative example and Example 1 is that ordinary vinyl polysiloxane (item number V304361) is used instead of fluorinated vinyl branched polysiloxane.

[0049] Comparative Example 3 The difference between this comparative example and Example 1 is that the filler was changed to 20 parts of ordinary magnesium hydroxide (item number M767093) and 10 parts of siloxane-treated fumed silica.

[0050] Comparative Example 4 The difference between this comparative example and Example 1 is that the filler was changed to 20 parts of vinyl-modified magnesium hydroxide and 10 parts of ordinary fumed silica (item number S697170).

[0051] Performance testing: The examples and comparative examples were first cured at 90°C for 4 hours, and then cured at 120°C for 2 hours to obtain test samples for the following tests.

[0052] (1) Thermal stability: The thermal stability of the examples and comparative examples was tested using a thermogravimetric analyzer (TGA550, TA Instruments, USA). The test atmosphere was nitrogen, the heating rate was set to 10℃ / min, and the test temperature range was 30℃~700℃. The thermal stability was evaluated using the temperature 5%Td at which the mass loss was 5wt%.

[0053] (2) Oxygen index: The test shall be conducted in accordance with the requirements of GB / T 2406.2-2009 Determination of combustion behavior of plastics by oxygen index method - Part 2: Room temperature test.

[0054] (3) Acid resistance: The sample was prepared into a standard sample piece of 50mm×50mm×2mm. Before the test, it was cleaned and dried and the initial mass was recorded. The sample was completely immersed in 1L of sulfuric acid solution with a mass concentration of 50% and soaked at room temperature for 120h. After soaking, the sample was taken out, rinsed with a large amount of flowing deionized water, placed in an oven and dried to constant weight. After cooling, the final mass was weighed and recorded. The mass reduction rate was calculated based on the mass difference before and after soaking to evaluate the acid resistance of the material.

[0055] (4) Alkali resistance: The sample was prepared into a standard sample piece of 50mm×50mm×2mm. Before the test, it was cleaned and dried and the initial mass was recorded. The sample was completely immersed in 1L of sodium hydroxide solution with a mass concentration of 40% and soaked at room temperature for 120h. After soaking, the sample was taken out, rinsed with a large amount of flowing deionized water, placed in an oven and dried to constant weight. After cooling, the final mass was weighed and recorded. The mass reduction rate was calculated based on the mass difference before and after soaking to evaluate the alkali resistance of the material.

[0056] The performance test data above are shown in Table 1.

[0057] Table 1 Performance Test Results

[0058] As can be seen from the above, the present invention first mixes melamine and paraformaldehyde to obtain a prepolymer, then adds hydroxyethyl acrylate to the prepolymer and stirs to obtain an unsaturated polyester. Then, the unsaturated polyester, filler, ethylene glycol dimethacrylate, vinyl polysiloxane, silane coupling agent, benzoyl peroxide and organic solvent are put into a mixing tank and stirred at room temperature and high speed to obtain an unsaturated resin composition that is resistant to high temperature and strong acids and alkalis (Examples 1 to 3), which has better overall performance.

[0059] Compared to Example 1, a common unsaturated polyester resin (model Aropol L 80305) was used. A) The unsaturated polyester prepared using the alternative technical solution of this invention lacks the effect of the triazine ring, resulting in decreased high-temperature resistance, reduced oxygen index, and worsened acid and alkali resistance (Comparative Example 1); Compared with Example 1, using ordinary vinyl polysiloxane (item number V304361) instead of fluorinated vinyl branched polysiloxane lacks the effect of fluorinated vinyl branched polysiloxane, resulting in decreased high-temperature resistance, reduced oxygen index, and worsened acid and alkali resistance (Comparative Example 2); Compared with Example 1, the filler was changed to 20 parts of ordinary magnesium hydroxide (item number M767093) and 10 parts of siloxane-treated fumed silica, lacking the effect of vinyl-modified magnesium hydroxide, resulting in decreased high-temperature resistance, reduced oxygen index, and worsened acid and alkali resistance (Comparative Example 3); Compared with Example 1, the filler was changed to 20 parts of vinyl-modified magnesium hydroxide and 10 parts of ordinary fumed silica (item number S697170), lacking the effect of siloxane-treated fumed silica, resulting in decreased high-temperature resistance, reduced oxygen index, and worsened acid and alkali resistance (Comparative Example 4).

Claims

1. A method for preparing a high-temperature resistant and strong acid-base resistant unsaturated resin composition, characterized in that, Includes the following steps: S1. First, melamine and paraformaldehyde are mixed to prepare a prepolymer. Then, hydroxyethyl acrylate is added to the prepolymer and stirred to react, resulting in an unsaturated polyester. S2. The unsaturated polyester, filler, ethylene glycol dimethacrylate, vinyl polysiloxane, silane coupling agent, benzoyl peroxide and organic solvent described in step S1 are added to a mixing tank and mixed at room temperature and high speed to obtain an unsaturated resin composition that is resistant to high temperature and strong acids and alkalis.

2. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 1, characterized in that, The components in step S2, by weight, include: 80-90 parts unsaturated polyester, 20-30 parts filler, 10-20 parts ethylene glycol dimethacrylate, 5-10 parts vinyl polysiloxane, 1-2 parts silane coupling agent, 1-2 parts benzoyl peroxide, and 180-200 parts organic solvent.

3. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 1, characterized in that, The preparation steps of the prepolymer are as follows: by weight, 120-130 parts of paraformaldehyde and 150-160 parts of methanol are added to a reaction vessel and mixed evenly. The pH is adjusted to 8.5-9.0 and the temperature is raised to 55-60℃ for 60-80 minutes. Then, 110-112 parts of melamine are added and the temperature is raised to 80-85℃ for 2-4 hours to obtain the prepolymer.

4. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 1, characterized in that, The stirring reaction steps are as follows: by weight, 230-240 parts of prepolymer are adjusted to pH 2-3 at 40-45℃, then 80-100 parts of hydroxyethyl acrylate, 2-4 parts of boric acid aqueous solution and 0.4-0.6 parts of hydroquinone are added and reacted at the temperature for 4-6 hours. The pH is adjusted to 6.5-7.0, methanol is removed by vacuum, the mixture is filtered, washed with petroleum ether, and dried under vacuum to obtain unsaturated polyester.

5. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 1, characterized in that, The filler is selected from one or more of magnesium hydroxide, aluminum hydroxide, calcium carbonate, silicon dioxide, and aluminum oxide.

6. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 5, characterized in that, The filler is magnesium hydroxide and silicon dioxide; The mass ratio of magnesium hydroxide to silicon dioxide is (1~2):

1.

7. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 6, characterized in that, The magnesium hydroxide is vinyl-modified magnesium hydroxide with a whiteness of 92-95%. 50 Particle size is 2~3μm, moisture content is 0.2~0.5%; The silica is siloxane-treated fumed silica with a specific surface area of ​​80~150m² / g, a drying loss of 0.2~0.5%, and a pH value of 4.5~6.

5.

8. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 1, characterized in that, The vinyl polysiloxane is a fluorinated vinyl branched polysiloxane; the fluorinated vinyl branched polysiloxane is prepared from methyltrimethoxysilane, vinyltrimethoxysilane and 3,3,3-trifluoropropyltrimethoxysilane as raw materials.

9. The method for preparing a high-temperature resistant and strong acid-alkali resistant unsaturated resin composition according to claim 8, characterized in that, The preparation steps of the fluorinated vinyl branched polysiloxane are as follows: by weight, 160-180 parts of anhydrous ethanol and 20-40 parts of deionized water are mixed, then 60-70 parts of methyltrimethoxysilane are added and the pH is adjusted to 4-5 and stirred for 2-4 hours. Then, 20-30 parts of vinyltrimethoxysilane and 5-10 parts of 3,3,3-trifluoropropyltrimethoxysilane are added, the temperature is raised to 60-70℃ and the reaction is carried out for 4-6 hours. After the reaction is completed, the mixture is cooled to room temperature, rotary evaporated, washed with deionized water, and vacuum dried to obtain the fluorinated vinyl branched polysiloxane.

10. A high-temperature resistant and strong acid- and alkali-resistant unsaturated resin composition, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9.

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