Flame-retardant and water-boiling-resistant polyester resin and its preparation process

Abstract

The invention discloses a flame-retardant and boiling-resistant polyester resin and a preparation process thereof, belonging to the technical field of resin materials. The flame-retardant and boiling-resistant polyester resin comprises the following raw materials in parts by weight: 90-110 parts of an unsaturated polyester resin, 14-18 parts of a flame retardant, 0.1-0.3 parts of a synergist, 1-3 parts of a curing agent, and 1-3 parts of an accelerator. The flame-retardant and boiling-resistant polyester resin comprises the following steps: step S1, stirring the unsaturated polyester resin and the flame retardant at a rotation speed of 600-800 r / min for 40-60 min to obtain a mixture; and step S2, adding a flame retardant auxiliary agent, a curing agent, and an accelerator to the mixture, stirring at a rotation speed of 3000-4000 r / min for 1-2 h to obtain the flame-retardant and boiling-resistant polyester resin. The flame-retardant and boiling-resistant polyester resin are added to the flame retardant and synergist containing nitrogen, phosphorus, silicon, and fluorine elements, thereby improving the flame retardancy of the polyester resin. The flame retardant and the synergist can also improve the boiling-resistant performance of the polyester resin.

Description

Technical Field

[0001] The invention belongs to the technical field of resin materials, and particularly relates to a flame-retardant and boiling-resistant polyester resin and a preparation process thereof. Background Art

[0002] Unsaturated polyester resin is one of the most widely used thermosetting resins. Its raw materials are readily available and inexpensive, and it exhibits good chemical resistance, excellent mechanical properties, and a wide processing temperature range. It can be cured at room temperature and pressure, making it widely used in various fields, including industry, transportation, construction, and national defense. However, unsaturated polyester resin is primarily composed of carbon and hydrogen, and its limiting oxygen index (LOD) is only 19.6%. It is highly flammable, and has poor flame retardancy and heat resistance. Combustion produces large amounts of harmful smoke. Furthermore, unsaturated polyester resin has a very poor char-forming ability, with a residual char rate of only 1.16% at 700°C. These poor flame retardancy hinders its further application.

[0003] In order to overcome the fire hazards of unsaturated polyester resins, additive flame retardants have the advantages of low cost and easy operation. To obtain better flame retardant effects, two or more additive flame retardants are often added to unsaturated polyester resins, and mechanical stirring is performed to obtain synergistic flame-retardant unsaturated polyester resins. However, due to the different properties, large dosages and poor dispersibility of different additive flame retardants, a clear separation layer will be generated during the pre-curing process of the unsaturated polyester resin, which not only reduces the mechanical properties of the unsaturated polyester resin, but also reduces the flame retardant properties. Summary of the Invention

[0004] The object of the present invention is to provide a flame retardant and water-boiling resistant polyester resin and a preparation process thereof, so as to solve the problems in the background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A flame-retardant and water-boiling-resistant polyester resin comprises the following raw materials in parts by weight:

[0007] 90-110 parts of unsaturated polyester resin, 14-18 parts of flame retardant, 0.1-0.3 parts of synergist, 1-3 parts of curing agent, 1-3 parts of accelerator;

[0008] The flame retardant is prepared by the following steps:

[0009] Step A1: Under nitrogen protection, tris(hydroxymethyl)aminomethane hydrochloride, triethylamine, and dioxane were added to a four-necked flask, stirred to dissolve, and then perfluorooctylethyltrichlorosilane was added dropwise at room temperature. After the addition was complete, the mixture was heated to 70°C and reacted until no gas escaped. The mixture was filtered while hot and post-treated to obtain Intermediate 1.

[0010] In the presence of dioxane as a solvent and under weak alkaline conditions, tris(hydroxymethyl)aminomethane hydrochloride reacts with perfluorooctylethyltrichlorosilane to obtain the fluorine- and silicon-containing intermediate 1. The reaction principle is as follows:

[0011]

[0012] Step A2: Under nitrogen protection, add intermediate 1, triethylamine and diethylene glycol dimethyl ether to a three-necked flask, stir and dissolve, then add phosphorus oxychloride dropwise at room temperature. After the addition is complete, heat to 110° C. and react until no gas escapes. Filter while hot and perform post-treatment to obtain a flame retardant.

[0013] In the presence of diethylene glycol dimethyl ether as a solvent and weakly alkaline conditions, intermediate 1 undergoes a substitution reaction with phosphorus oxychloride to obtain a flame retardant containing nitrogen, phosphorus, silicon, and fluorine. This flame retardant has a highly symmetrical and stable molecular structure and can be evenly dispersed in unsaturated polyester resin. The nitrogen, phosphorus, and silicon elements can achieve an excellent synergistic flame retardant effect. The flame retardant not only has good water repellency but also has good thermal stability, making it difficult for the flame retardant to be hydrolyzed and lost in the unsaturated polyester resin and having good water boiling resistance. The reaction principle is as follows:

[0014]

[0015] Furthermore, the usage ratio of tris(hydroxymethyl)aminomethane hydrochloride, triethylamine, dioxane and perfluorooctylethyltrichlorosilane is 30-30.5 g: 25-26 g: 250 mL: 150-160 g.

[0016] Furthermore, the usage ratio of the intermediate 1, triethylamine, diethylene glycol dimethyl ether and phosphorus oxychloride is 18-18.5 g: 1.5-1.55 g: 50 mL: 1.5-1.55 g.

[0017] Furthermore, the post-treatment in step A1 and step A2 includes: adding the filtered solid to 10-20 times the volume of deionized water, stirring and mixing, then adjusting the pH to 8 with triethylamine, filtering and washing with deionized water 2-3 times.

[0018] Furthermore, the synergist is prepared by the following steps:

[0019] Graphene oxide was dispersed in ethanol and sealed with ultrasound for 30 minutes to obtain a graphene oxide dispersion. 1-Butyl-3-methylimidazolium hexafluorophosphate and deionized water were added to the graphene oxide dispersion, and 3-aminopropyltriethoxysilane was added dropwise during magnetic stirring. The mixture was stirred for 1 hour, filtered, washed with anhydrous ethanol for 3 times, dried, and ground to obtain a synergist.

[0020] The present invention grafts 1-butyl-3-methylimidazolium hexafluorophosphate onto the surface of graphene oxide via 3-aminopropyltriethoxysilane to prepare a flame retardant synergist. By adding a small amount of the synergist, the flame retardant performance of the flame retardant can be further improved, the carbonization of unsaturated polyester resin can be promoted during combustion, the thermal cracking rate of the polyester resin can be reduced, volatile combustibles can be reduced, and the combustion and spread of flames can be hindered.

[0021] Furthermore, the usage ratio of the graphene oxide, ethanol, 1-butyl-3-methylimidazolium hexafluorophosphate, deionized water and 3-aminopropyltriethoxysilane is 0.2 g: 50-60 mL: 1-2 mL: 20 mL: 0.1-0.2 mL; and the graphene oxide is prepared by the Hummers method.

[0022] Furthermore, the curing agent is a mixture of one or more of methyl ethyl ketone peroxide, cyclohexanone peroxide, and benzoyl peroxide in any ratio.

[0023] Furthermore, the accelerator is one of cobalt epoxyate and cobalt isooctanoate, or a mixture of the two in any ratio.

[0024] A preparation process of a flame-retardant and water-boiling-resistant polyester resin comprises the following steps:

[0025] Step S1, stirring the unsaturated polyester resin and the flame retardant at a rotation speed of 600-800 r / min for 40-60 min to obtain a mixture;

[0026] Step S2: adding a flame retardant auxiliary agent, a curing agent and an accelerator to the mixture, stirring for 1-2 hours at a rotation speed of 3000-4000 r / min to obtain a flame retardant and water-boiling resistant polyester resin.

[0027] Beneficial effects of the present invention:

[0028] The flame retardant molecules prepared by the present invention contain nitrogen, phosphorus, silicon and fluorine elements at the same time. Compared with the compound use of nitrogen-based, phosphorus-based and silicon-based additive flame retardants, the flame retardant prepared by the present invention is well compatible with unsaturated polyester resin and is evenly dispersed in the unsaturated polyester resin without affecting the mechanical properties of the unsaturated polyester resin. Moreover, during combustion, the three flame retardant elements of nitrogen, phosphorus and silicon can effectively exert a synergistic flame retardant effect, forming an oxygen-insulating and heat-insulating protective layer on the surface of the material, effectively isolating the air and preventing heat transfer, thereby achieving good flame retardant and anti-melting dripping effects.

[0029] When used together with the flame retardant, the synergist of the present invention can further promote the carbonization of the unsaturated polyester resin during combustion, forming a thicker, harder, and denser carbon layer on the surface of the polyester resin. This effectively isolates heat transfer between the combustion zone and the resin matrix, while suppressing the release of smoke, thereby achieving better flame retardancy and anti-dripping effects.

[0030] Finally, the flame retardant and synergist prepared by the present invention contain a large amount of fluorine element, which can form a hydrophobic layer on the surface of the polyester resin, reduce the entry of moisture into the interior of the polyester resin, significantly improve the boiling resistance of the polyester resin, and ensure the reliability of use in a humid and hot environment. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a flame retardant, which is prepared by the following steps:

[0034] Step A1, under nitrogen protection, to a 500 mL four-necked flask, 30 g of tris(hydroxymethyl)aminomethane hydrochloride, 25 g of triethylamine and 250 mL of dioxane were added, stirred and dissolved, and 150 g of perfluorooctylethyltrichlorosilane was added dropwise at room temperature. After the addition was complete, the mixture was heated to 70° C. and reacted until no gas escaped. The filtered solid was added to 10 times the volume of deionized water and stirred, and then the pH was adjusted to 8 with triethylamine. The mixture was filtered and washed twice with deionized water to obtain Intermediate 1;

[0035] Step A2, under nitrogen protection, to a 100 mL three-necked flask, 18 g of intermediate 1, 1.5 g of triethylamine and 50 mL of diethylene glycol dimethyl ether were added, stirred and dissolved, and 1.5 g of phosphorus oxychloride was added dropwise at room temperature. After the addition was complete, the mixture was heated to 110 ° C and reacted until no gas escaped. The filtered solid was added to 10 times the volume of deionized water and stirred, and then the pH was adjusted to 8 with triethylamine, filtered and washed twice with deionized water to obtain a flame retardant.

[0036] Example 2

[0037] This embodiment provides a flame retardant, which is prepared by the following steps:

[0038] Step A1, under nitrogen protection, to a 500 mL four-necked flask, 30.2 g of tris(hydroxymethyl)aminomethane hydrochloride, 25.5 g of triethylamine and 250 mL of dioxane were added, stirred and dissolved, and 155 g of perfluorooctylethyltrichlorosilane was added dropwise at room temperature. After the addition was complete, the mixture was heated to 70° C. and reacted until no gas escaped. The mixture was filtered while hot, and the filtered solid was added to 15 times the volume of deionized water and stirred. The pH was then adjusted to 8 with triethylamine, filtered, and washed three times with deionized water to obtain Intermediate 1;

[0039] Step A2, under nitrogen protection, to a 100mL three-necked flask, 18.3g of intermediate 1, 1.52g of triethylamine and 50mL of diethylene glycol dimethyl ether were added, stirred and dissolved, and 1.53g of phosphorus oxychloride was added dropwise at room temperature. After the addition was complete, the mixture was heated to 110°C and reacted until no gas escaped. The filtered solid was added to 15 times the volume of deionized water and stirred, and then the pH was adjusted to 8 with triethylamine, filtered and washed 3 times with deionized water to obtain a flame retardant.

[0040] Example 3

[0041] This embodiment provides a flame retardant, which is prepared by the following steps:

[0042] Step A1, under nitrogen protection, to a 500 mL four-necked flask, 30.5 g of tris(hydroxymethyl)aminomethane hydrochloride, 26 g of triethylamine and 250 mL of dioxane were added, stirred and dissolved, and 160 g of perfluorooctylethyltrichlorosilane was added dropwise at room temperature. After the addition was complete, the mixture was heated to 70° C. and reacted until no gas escaped. The filtered solid was added to 20 volumes of deionized water and stirred, and then the pH was adjusted to 8 with triethylamine. The mixture was filtered and washed three times with deionized water to obtain Intermediate 1;

[0043] Step A2, under nitrogen protection, to a 100 mL three-necked flask, 18.5 g of intermediate 1, 1.55 g of triethylamine and 50 mL of diethylene glycol dimethyl ether were added, stirred and dissolved, and 1.55 g of phosphorus oxychloride was added dropwise at room temperature. After the addition was complete, the mixture was heated to 110 ° C and reacted until no gas escaped. The filtered solid was added to 20 times the volume of deionized water and stirred, and then the pH was adjusted to 8 with triethylamine, filtered and washed 3 times with deionized water to obtain a flame retardant.

[0044] Example 4

[0045] This embodiment provides a synergist, which is prepared by the following steps:

[0046] 0.2 g of graphene oxide was dispersed in 50 mL of ethanol and sealed with ultrasound for 30 min to obtain a graphene oxide dispersion. 1 mL of 1-butyl-3-methylimidazolium hexafluorophosphate and 20 mL of deionized water were added to the graphene oxide dispersion. 0.1 mL of 3-aminopropyltriethoxysilane was added dropwise during magnetic stirring. The mixture was stirred for 1 h, filtered, washed with anhydrous ethanol three times, dried, and ground to obtain a synergist.

[0047] Example 5

[0048] This embodiment provides a synergist, which is prepared by the following steps:

[0049] 0.2 g of graphene oxide was dispersed in 55 mL of ethanol and sealed with ultrasound for 30 min to obtain a graphene oxide dispersion. 1.5 mL of 1-butyl-3-methylimidazolium hexafluorophosphate and 20 mL of deionized water were added to the graphene oxide dispersion. 0.15 mL of 3-aminopropyltriethoxysilane was added dropwise during magnetic stirring. The mixture was stirred for 1 h, filtered, washed with anhydrous ethanol three times, dried, and ground to obtain a synergist.

[0050] Example 6

[0051] This embodiment provides a synergist, which is prepared by the following steps:

[0052] 0.2 g of graphene oxide was dispersed in 60 mL of ethanol and sealed with ultrasound for 30 min to obtain a graphene oxide dispersion. 2 mL of 1-butyl-3-methylimidazolium hexafluorophosphate and 20 mL of deionized water were added to the graphene oxide dispersion. 0.2 mL of 3-aminopropyltriethoxysilane was added dropwise during magnetic stirring. The mixture was stirred for 1 h, filtered, washed with anhydrous ethanol three times, dried, and ground to obtain a synergist.

[0053] Example 7

[0054] A flame-retardant and water-boiling-resistant polyester resin comprises the following raw materials in parts by weight:

[0055] 90 parts of unsaturated polyester resin, 14 parts of the flame retardant prepared in Example 1, 0.1 parts of the synergist prepared in Example 4, 1 part of methyl ethyl ketone peroxide, and 1 part of cobalt epoxylate;

[0056] The preparation process comprises the following steps:

[0057] Step S1, stirring the unsaturated polyester resin and the flame retardant prepared in Example 1 at a rotation speed of 600 r / min for 40 minutes to obtain a mixture;

[0058] Step S2: adding the flame retardant auxiliary agent, curing agent and accelerator prepared in Example 4 to the mixture, stirring at a rotation speed of 3000 r / min for 1 hour to obtain a flame retardant and water-boiling resistant polyester resin.

[0059] Example 8

[0060] A flame-retardant and water-boiling-resistant polyester resin comprises the following raw materials in parts by weight:

[0061] 100 parts of unsaturated polyester resin, 16 parts of the flame retardant prepared in Example 2, 0.2 parts of the synergist prepared in Example 5, 2 parts of cyclohexanone peroxide, and 2 parts of cobalt isooctanoate;

[0062] The preparation process comprises the following steps:

[0063] Step S1, stirring the unsaturated polyester resin and the flame retardant prepared in Example 2 at a rotation speed of 700 r / min for 50 minutes to obtain a mixture;

[0064] Step S2: adding the flame retardant auxiliary agent, curing agent and accelerator prepared in Example 5 to the mixture, stirring at a rotation speed of 3500 r / min for 1.5 hours to obtain a flame retardant and water-boiling resistant polyester resin.

[0065] Example 9

[0066] A flame-retardant and water-boiling-resistant polyester resin comprises the following raw materials in parts by weight:

[0067] 110 parts of unsaturated polyester resin, 18 parts of the flame retardant prepared in Example 3, 0.3 parts of the synergist prepared in Example 6, 3 parts of benzoyl peroxide, and 3 parts of cobalt epoxide;

[0068] The preparation process comprises the following steps:

[0069] Step S1, stirring the unsaturated polyester resin and the flame retardant prepared in Example 3 at a rotation speed of 800 r / min for 60 min to obtain a mixture;

[0070] Step S2: adding the flame retardant auxiliary agent, curing agent and accelerator prepared in Example 6 to the mixture, stirring at a rotation speed of 4000 r / min for 2 hours to obtain a flame retardant and water-boiling resistant polyester resin.

[0071] Comparative Example 1

[0072] Compared with Example 8, this comparative example uses ammonium polyphosphate, melamine, and dimethyldichlorosilane mixed in equal proportions to replace an equal amount of the flame retardant prepared in Example 2, and the remaining raw materials and steps are the same.

[0073] Comparative Example 2

[0074] Compared with Example 8, this comparative example does not add the synergist prepared in Example 5, and the remaining raw materials and steps are the same.

[0075] Comparative Example 3

[0076] Compared with Example 8, this comparative example uses graphene oxide to replace the synergist prepared in Example 5, and the other raw materials and steps are the same.

[0077] The polyester resins prepared in Examples 7 to 9 and Comparative Examples 1 to 3 were subjected to performance tests. The oxygen index (LOI) of the polyester resins was tested according to GB / T 2406.1-2008. The vertical burning rating (UL-94) of the polyester resins was tested according to ASTM D 3801-2010, and the presence of molten dripping was observed. The polyester resins were boiled in boiling water for 2 hours and observed for blistering, cracking, and discoloration. The results are shown in Table 1.

[0078] Table 1

[0079]

[0080] It can be seen from the results in Table 1 that, compared with Comparative Examples 1 to 3, the polyester resins prepared in Examples 7 to 9 have a higher oxygen index, a higher vertical combustion grade, no dripping phenomenon occurs during combustion, and have excellent water boiling resistance.

[0081] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0082] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A flame retardant and boiling-resistant polyester resin, characterized in that: It includes the following raw materials in parts by weight: 90-110 parts of unsaturated polyester resin, 14-18 parts of flame retardant, 0.1-0.3 parts of synergist, 1-3 parts of curing agent, 1-3 parts of accelerator; The flame retardant is prepared by the following steps: Step A1. Under nitrogen protection, tris(hydroxymethyl)aminomethane hydrochloride, triethylamine, and dioxane were added to a four-necked flask, stirred to dissolve, and perfluorooctylethyltrichlorosilane was added dropwise at room temperature. After the addition was complete, the mixture was heated to 70° C. and reacted until no gas escaped. The mixture was filtered while hot and post-treated to obtain intermediate 1. The ratio of tris(hydroxymethyl)aminomethane hydrochloride, triethylamine, dioxane, and perfluorooctylethyltrichlorosilane was 30-30.5 g: 25-26 g: 250 mL: 150-160 g. Step A2, under nitrogen protection, add intermediate 1, triethylamine and diethylene glycol dimethyl ether to a three-necked flask, stir and dissolve, add phosphorus oxychloride dropwise at room temperature, heat to 110°C after the addition is complete, react until no gas escapes, filter while hot and perform post-treatment to obtain a flame retardant; the amount ratio of the intermediate 1, triethylamine, diethylene glycol dimethyl ether and phosphorus oxychloride is 18-18.5g:1.5-1.55g:50mL:1.5-1.55g; The synergist is prepared by the following steps: Graphene oxide is dispersed in ethanol and sealed and ultrasonicated for 30 minutes to obtain a graphene oxide dispersion; 1-butyl-3-methylimidazolium hexafluorophosphate and deionized water are added to the graphene oxide dispersion, and 3-aminopropyltriethoxysilane is added dropwise during magnetic stirring. The amount ratio of the graphene oxide, ethanol, 1-butyl-3-methylimidazolium hexafluorophosphate, deionized water and 3-aminopropyltriethoxysilane is 0.2g:50-60mL:1-2mL:20mL:0.1-0.2mL. The reaction is stirred for 1 hour, filtered and washed with anhydrous ethanol, dried and ground to obtain a synergist.

2. The flame retardant and boiling-resistant polyester resin according to claim 1, characterized in that: The post-treatment comprises: adding the filtered solid into 10-20 times the volume of deionized water and stirring and mixing, then adjusting the pH to 8 with triethylamine, filtering and washing with deionized water for 2-3 times.

3. The flame retardant and boiling-resistant polyester resin according to claim 1, characterized in that: The curing agent is a mixture of one or more of methyl ethyl ketone peroxide, cyclohexanone peroxide, and benzoyl peroxide in any ratio.

4. The flame retardant and boiling-resistant polyester resin according to claim 1, characterized in that: The accelerator is one of cobalt naphthenate and cobalt isooctanoate, or a mixture of the two in any ratio.

5. The process for preparing a flame retardant and water-boiling resistant polyester resin according to claim 1, characterized in that: The following steps are involved: Step S1, stirring the unsaturated polyester resin and the flame retardant at a rotation speed of 600-800 r / min for 40-60 min to obtain a mixture; Step S2: adding a synergist, a curing agent and an accelerator to the mixture, stirring at a rotation speed of 3000-4000 r / min for 1-2 hours to obtain a flame-retardant and water-boiling-resistant polyester resin.

Images