High-heat-resistance self-toughening functional resin composition, prepreg and laminated board

Abstract

The invention discloses a high-heat-resistance self-toughening functional resin composition, a prepreg and a laminated board, and relates to the technical field of composite materials. The resin composition comprises the following raw materials in parts by weight: 30-60 parts of epoxy polyfunctional group-containing resin, 30-50 parts of special benzoxazine resin, 10-18 parts of a flame retardant, 0.1-1 part of a catalyst and 1-5 parts of a curing agent, the special benzoxazine resin has the following structural characteristics: any one of R1 and R2 is H, and the other one is a group containing an olefin carbon-carbon double bond. In the subsequent curing stage of the resin composition provided by the invention, stepped cross-linking points are introduced, so that the self-toughening process of the cured matrix resin can be realized, and meanwhile, effective unification of high heat resistance and high flame retardance is realized through the intermolecular acting force of the matrix resin and the density of the cross-linking points; therefore, the defects caused by improving the composite toughness by externally adding a high-molecular-weight thermoplastic reinforcing body are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, in particular to a high-heat-resistant self-toughening functional resin composition, a prepreg and a laminate. Background Art

[0002] With the development of carbon fiber resin-based composites, a growing number of market applications are emerging. Market demand for carbon fiber composites is no longer solely focused on excellent mechanical properties (specific stiffness and specific modulus), but is increasingly focused on the integration of mechanical properties and functionality. For example, composite materials used in civil aircraft require high heat resistance, high strength, and high modulus, while also possessing excellent toughness to increase the end product's tolerance after impact under normal operating conditions. In the rail transit sector, high heat resistance is not a requirement, but very stringent flame retardancy requirements are placed on the end product. In the defense aviation sector, designers and manufacturers are also attempting to integrate stealth performance with composite material functionality. As a result, functional carbon fiber composites have gradually become the new favorite in the composites industry.

[0003] In the field of marine vessels, the application of carbon fiber composite materials is also ubiquitous. However, traditional composite hull manufacturing is mostly completed by using vinyl liquid resin combined with carbon fiber reinforcement in a vacuum infusion process. This type of product does not require high mechanical properties of the material. At the same time, because it is a low-speed passenger ship and the product is mostly in direct or indirect contact with water, the flame retardant and fireproof requirements are not urgent. With the continuous maturity of carbon fiber composite materials in aviation, aerospace, and rail transportation, the load-bearing structure design of marine hulls and underwater hulls has gradually shifted from steel structure to composite structure. This requires composite materials to have high performance while also combining their functionality, such as high rigidity, high toughness and flame retardant properties, especially to meet the fire resistance test requirements (FTP rules) issued by the International Maritime Organization.

[0004] Currently, high-strength, high-toughness carbon fiber composites are primarily used in civil aviation. Toughening is achieved through two main methods: melting thermoplastic particles into an epoxy resin system. This method alters the epoxy resin's fluidity and fiber wettability at high temperatures. To mitigate these effects, most prepreg manufacturing processes employ methods such as increasing temperature and pressurizing. However, this approach also presents the problem of fiber damage, impacting the mechanical properties of subsequent components. Regarding flame retardancy, resin-based carbon fiber composites are primarily epoxy resin-based, which offers advantages in cost and processing. However, their main drawback is their flammability and the significant amount of smoke generated during combustion, posing a significant risk for their use in submarine hull composites. While flame retardant composites are currently widely used in rail transit, most are medium-temperature curing systems, with glass transition temperatures ranging from 110°C to 130°C. For underwater hull applications, high-temperature cured high-temperature resistant prepreg systems are mostly used. Compared with medium-temperature cured systems, their flame retardancy and fire resistance are worse. The high-temperature resistant prepreg system mainly prevents the movement of molecular chains by increasing cross-linking points in the molecular structure. It itself cannot block the burning of flames (600°C). Compared with medium-temperature cured systems, there are more CC bonds in the high-heat resistant structure, which is more likely to break during the flame combustion process, forming flammable gases and smoke, which has an adverse effect on flame retardancy.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-heat-resistant self-toughening functional resin composition, a prepreg and a laminate.

[0007] The present invention is achieved in that: In a first aspect, the present invention provides a high heat-resistant self-toughening functional resin composition, wherein the raw materials thereof include, by weight, 30 to 60 parts of epoxy multifunctional resin, 30 to 50 parts of special benzoxazine resin, 10 to 18 parts of flame retardant, 0.1 to 1 part of catalyst and 1 to 5 parts of curing agent; The special benzoxazine resin has the following structural characteristics: , Wherein, either R1 or R2 is H, and the other is a group containing an olefinic carbon-carbon double bond.

[0008] In an optional embodiment, the group containing an olefin carbon-carbon double bond is selected from one of the following groups: , , , , , , , , , , , , , , where * indicates the attachment site.

[0009] In an optional embodiment, the epoxy multifunctional resin is one or more of Araldite MY0500, Araldite MY0600, Tactix 742, Araldite MY720, Araldite MY721, Araldite XB9721, AralditeMY9663, ERISYS GA-240, and Tactix 756.

[0010] In an optional embodiment, the flame retardant includes one or more of organic phosphate flame retardants, polyphosphate amine (type II), melamine urate, organic phosphonate, polyphosphate melamine, organic montmorillonite, borate and silicate.

[0011] In an optional embodiment, the catalyst includes one or more of trioctylmethylammonium persulfate, tert-butyl hydroperoxide, tert-amyl peroxy-2-ethylhexanoate (TAPO), diisopropylbenzene peroxide (DCP), di-tert-butyl peroxide (DTBP), isopropylbenzene hydroperoxide, tert-butyl peroxybenzoate (TBPB), 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and a,a"-bis(tert-butylperoxy)diisopropylbenzene.

[0012] In an optional embodiment, the curing agent is one or more of the following structures: .

[0013] In a second aspect, the present invention provides a prepreg comprising continuous fibers and a high heat-resistant self-toughening functional resin composition as described in any one of the aforementioned embodiments, wherein the high heat-resistant self-toughening functional resin composition is coated to form a resin film, which is then impregnated with the continuous fibers to obtain the prepreg.

[0014] In an optional embodiment, the surface density of the continuous fibers is in the range of 50 to 300 g / m 2 .

[0015] In a third aspect, the present invention provides a laminate comprising the prepreg according to any one of the aforementioned embodiments.

[0016] In an optional embodiment, the method for preparing the laminate includes performing step-by-step curing on the prepreg, wherein the step-by-step curing includes first performing a first stage curing at 100-120°C, then performing a second stage curing at 160-180°C, and finally performing a third stage curing at 200-220°C.

[0017] In an optional embodiment, the holding time of the first stage curing is 0.5-1.5h, and the heating rate is 1-3°C / min; And / or, the second stage curing holding time is 1-2 hours, and the heating rate is 1-3°C / min; And / or, the holding time of the third stage curing is 1.5-2.5 hours, and the heating rate is 1-3°C / min.

[0018] The present invention has the following beneficial effects: The present invention provides a high-heat-resistant self-toughening functional resin composition, which aims to solve industry difficulties, especially the difficulties encountered by high-rigidity and high-toughness resins during their application. The core of this method lies in the precise definition of raw materials, especially by designing the structure of a special benzoxazine resin - selecting a group containing an olefin carbon-carbon double bond on one side as a substituent of the benzoxazine resin, so that the resin can undergo a double bond opening addition reaction under the action of a catalyst in the subsequent curing stage, thereby forming a chain copolymer prepolymer with a tough structure. To achieve this effect, only R1 or R2 in this application contains an olefin, thereby ensuring that the special benzoxazine resin can be connected one by one through the olefin to form a long-chain flexible compound, thereby effectively avoiding the situation where a macrocyclic structure may appear when R1 and R2 contain olefins at the same time. At the same time, since the special benzoxazine resin itself contains a benzene ring structure, it can also undergo a ring-opening curing reaction with a resin containing an epoxy multifunctional group. Therefore, the high-heat-resistant self-toughening functional resin composition provided by the present invention can simultaneously achieve properties such as self-toughening, high heat resistance and high flame retardancy during the curing process.

[0019] The laminate provided by the present invention starts from the molecular structure design and introduces a "step-by-step" reaction cross-linking point. By controlling the curing temperature, it can not only achieve the synergy of self-toughening, high heat resistance and high flame retardancy, but also complete the self-toughening of the cured main resin by orderly regulating the curing stage of the matrix resin. By optimizing the intermolecular force of the matrix resin and the cross-linking point density, the high heat resistance and high flame retardancy are unified, thereby avoiding the disadvantages of improving the composite toughness by adding a high molecular weight thermoplastic reinforcement. The problem encountered by the uncured resin in the prepreg preparation process can be fully reduced. The difficulty of the back-end prepreg preparation can be fully reduced. There is no need to force the high temperature and high pressure mode to solve the problem of insufficient impregnation of the prepreg. At the same time, the reduction in the difficulty of the manufacturing process also reduces the loss of fibers in the prepreg manufacturing process, reduces the manufacturing cost and process controllability, and the viscosity life of the high temperature curing prepreg system at room temperature of 25 ° C is as high as 28 days. At the same time, through clever design, the toughness performance of the plate after the prepreg is cured is fully improved, while ensuring stiffness and retaining toughness. In addition, the flame retardant and fireproof performance has also been substantially improved, which can achieve the most stringent combustion and smoke requirements in the fire resistance test requirements (FTP rules) issued by the International Maritime Organization. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0021] The present invention provides a high-heat-resistant self-toughening functional resin composition, wherein the raw materials thereof include, by weight, 30 to 60 parts of epoxy multifunctional resin, 30 to 50 parts of special benzoxazine resin, 10 to 18 parts of flame retardant, 0.1 to 1 part of catalyst and 1 to 5 parts of curing agent; Special benzoxazine resin has the following structural characteristics: , Wherein, either R1 or R2 is H, and the other is a group containing an olefinic carbon-carbon double bond.

[0022] The group containing an olefinic carbon-carbon double bond is selected from one of the following groups: , , , , , , , , , , , , , , where * indicates the attachment site.

[0023] In this invention, a special benzoxazine resin is formed by replacing a benzoxazine resin with a substituent R1 or R2 containing an olefin (C=C double bond) through structural design. During the subsequent curing stage, this special benzoxazine resin undergoes a double bond-opening addition reaction under the action of a catalyst, thereby forming a chain copolymer prepolymer with a tough structure. Furthermore, because the special benzoxazine resin itself contains a benzene ring structure, it can also undergo a ring-opening curing reaction with a multifunctional epoxy resin. In this application, only R1 or R2 contains an olefin, ensuring that the special benzoxazine resin can be linked one by one through the olefin to form a long-chain flexible compound, effectively avoiding the formation of a macrocyclic structure that may occur when both R1 and R2 contain olefins.

[0024] In some embodiments, the epoxy multifunctional resin includes but is not limited to one or more of Araldite MY0500, Araldite MY0600, Tactix 742, Araldite MY720, Araldite MY721, Araldite XB9721, Araldite MY9663, ERISYS GA-240, and Tactix 756, or may be a resin of a different brand with the same structure as the above.

[0025] In some embodiments, the flame retardant includes, but is not limited to, one or more of organophosphate flame retardants, polyphosphate amine (type II), melamine urate, organic phosphonates, polyphosphate melamine, organic montmorillonite, borates, and silicates.

[0026] In some embodiments, the catalyst includes, but is not limited to, one or more of trioctylmethylammonium persulfate, tert-butyl hydroperoxide, tert-amyl peroxy-2-ethylhexanoate (TAPO), diisopropylbenzene peroxide (DCP), di-tert-butyl peroxide (DTBP), isopropylbenzene hydroperoxide, tert-butyl peroxybenzoate (TBPB), 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and a,a"-bis(tert-butylperoxy)diisopropylbenzene.

[0027] In some embodiments, the curing agent includes but is not limited to dicyandiamide. GLOC-300 GLOC-400 GLOC-500 GLOC-800 、DMU , 2MZ-OK 、2MZ-AZINE 、2E4MZ-AZINE 、C11Z-AZINE , 2PHZ and 2P4MHZ One or more of the above can also be a curing agent of different brands with the same structure as the above.

[0028] The preparation method of the above-mentioned high heat-resistant self-toughening functional resin composition is simple. It only requires that the above-mentioned raw materials be mixed evenly. During the mixing process, the epoxy multifunctional resin can be first added to the mixing kettle, heated to 80-100°C, and fully stirred until the mixture is evenly mixed. The special benzoxazine resin is added and fully stirred until the mixture is evenly mixed. The flame retardant is added and fully stirred. The temperature is lowered to 50-60°C, the catalyst is added, stirred evenly, and then the curing agent is added. The material is evenly stirred for 5-10 minutes and discharged to obtain the high heat-resistant self-toughening functional resin composition as a prepreg resin.

[0029] Furthermore, the present invention provides a prepreg comprising continuous fibers and the above-mentioned high heat-resistant self-toughening functional resin composition. The high heat-resistant self-toughening functional resin composition is coated to form a resin film, which is then impregnated with the continuous fibers. The impregnation temperature is controlled below 90°C to obtain a prepreg.

[0030] Among them, the continuous fiber is Hengshen HF30T (Toray T700SC grade) continuous carbon fiber, which is a planar material with uniform surface density through orderly arrangement. The surface density of the continuous fiber ranges from 50 to 300 g / m 2 , the tensile strength of continuous fiber is required to be ≥4900MPa and the tensile modulus is ≥245GPa.

[0031] Furthermore, the present invention provides a laminate comprising the prepreg.

[0032] Specifically, the preparation method of the laminate includes step-curing the prepreg, wherein the step-curing includes first-stage curing at 100-120°C, then second-stage curing at 160-180°C, and finally third-stage curing at 200-220°C.

[0033] Among them, the holding time of the first stage curing is 0.5-1.5h, and the heating rate is 1-3℃ / min; the holding time of the second stage curing is 1-2h, and the heating rate is 1-3℃ / min; the holding time of the third stage curing is 1.5-2.5h, and the heating rate is 1-3℃ / min.

[0034] To optimize the curing effect, the present invention adopts a step-by-step curing method: in the first stage, the temperature is set to 100-120°C. At this time, the catalyst in the system will promote the double bond of the special benzoxazine to undergo a bond-opening addition reaction, completing the first stage pre-crosslinking and forming a chain copolymer prepolymer with a tough structure. At the same time, the heat released by the reaction can accelerate the dissolution of the curing agent, providing power for the subsequent curing reaction; in the second stage, the temperature is increased to 160-180°C, mainly used to promote the epoxy resin and the special epoxy resin to undergo a ring-opening curing reaction under the action of heat; in the third stage, the temperature is further increased to 200-220°C, prompting the crosslinking points on the high-steric macromolecular chain to overcome the energy barrier and continue to react, thereby increasing the crosslinking density and enhancing the overall heat resistance of the prepreg after curing. The present invention not only realizes the synergy of self-toughening, high heat resistance and high flame retardancy by controlling the curing temperature, but also completes the self-toughening of the cured main resin by orderly regulating the curing stage of the matrix resin, and realizes the unification of high heat resistance and high flame retardancy by optimizing the intermolecular force and cross-linking point density of the matrix resin, thereby avoiding the disadvantages brought about by the use of externally added high molecular weight thermoplastic reinforcements to improve the composite toughness.

[0035] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0036] Example 1 This embodiment provides a highly heat-resistant self-toughening functional resin composition and a prepreg and laminate prepared therefrom.

[0037] (1) First, weigh and mix the modified ingredients according to their weight: multifunctional epoxy resin: 45 parts, special benzoxazine resin: 38.8 parts, flame retardant: 14 parts, catalyst: 0.2 parts, curing agent: 2 parts. Add 10 parts of Tactix 756 resin and 35 parts of Araldite XB9721 resin to a mixing kettle, heat to 85°C, stir thoroughly until the mixture is uniform, and add special benzoxazine resin. 38.8 parts of the mixture were stirred thoroughly until uniformly mixed, 10 parts of the flame retardant polyphosphate ammonium (type II) and 4 parts of zinc borate were added, and after fully stirring, the temperature was lowered to 55°C, 0.2 parts of the catalyst tert-butyl peroxybenzoate (TBPB) was added, and after stirring evenly, 2 parts of the curing agent dicyandiamide were added, and the mixture was stirred evenly for 8 minutes to obtain the prepreg resin.

[0038] (2) The prepreg resin is coated on a continuous coating machine as a fixed weight resin film and mixed with 133g / m 2 HF30T fibers with uniform surface density and unidirectional arrangement were impregnated at a maximum impregnation temperature of 90° C. to obtain prepreg S1-1.

[0039] (3) Autoclave curing: gradually increase the temperature from room temperature to 110°C at 2°C / min, keep it at that temperature for 1 hour, then gradually increase the temperature to 180°C at 2°C / min and keep it at that temperature for 1.5 hours, and then gradually increase the temperature to 210°C at 2°C / min and keep it at that temperature for 2 hours. The laminate product S1-2 obtained under this curing process.

[0040] Example 2 This embodiment provides a highly heat-resistant self-toughening functional resin composition and a prepreg and laminate prepared therefrom.

[0041] (1) First, weigh and mix the modified ingredients according to their weight: 53.9 parts of multifunctional epoxy resin, 30 parts of special benzoxazine resin, 14 parts of flame retardant, 0.1 parts of catalyst, and 2 parts of curing agent. Add 23.9 parts of Tactix 756 resin and 30 parts of Araldite XB9721 resin to a mixing kettle, heat to 85°C, stir thoroughly until the mixture is evenly mixed, and add the special benzoxazine resin. 30 parts of methyl paraben were mixed, stirred thoroughly until the mixture was uniform, 10 parts of flame retardant polyphosphate ammonium (type II) and 4 parts of zinc borate were added, stirred thoroughly, cooled to 55°C, 0.1 parts of catalyst tert-butyl peroxybenzoate (TBPB) were added, stirred thoroughly, and then 2 parts of curing agent dicyandiamide were added, stirred thoroughly for 8 minutes, and the prepreg resin was obtained.

[0042] (2) The prepreg resin is coated on a continuous coating machine as a fixed weight resin film and mixed with 133g / m 2 HF30T fibers with uniform surface density and unidirectional arrangement were impregnated at a maximum impregnation temperature of 90° C. to obtain prepreg S2-1.

[0043] (3) Autoclave curing: gradually increase the temperature from room temperature to 110°C at 2°C / min, keep it at that temperature for 1 hour, then gradually increase the temperature to 180°C at 2°C / min and keep it at that temperature for 1.5 hours, and then gradually increase the temperature to 210°C at 2°C / min and keep it at that temperature for 2 hours. The laminate product S2-2 obtained under this curing process.

[0044] Example 3 This embodiment provides a highly heat-resistant self-toughening functional resin composition and a prepreg and laminate prepared therefrom.

[0045] (1) First, weigh and mix the modified ingredients according to their weight: 34 parts of multifunctional epoxy resin, 49.7 parts of special benzoxazine resin, 14 parts of flame retardant, 0.3 parts of catalyst, and 2 parts of curing agent. Add 8 parts of Tactix 756 resin and 26 parts of Araldite XB9721 resin to a mixing kettle, heat to 85°C, stir thoroughly until the mixture is evenly mixed, and add the special benzoxazine resin. 49.7 parts of the mixture were stirred thoroughly until the mixture was uniformly mixed, 10 parts of the flame retardant melamine polyphosphate and 4 parts of the organic montmorillonite were added, and the mixture was fully stirred. The temperature was lowered to 55°C, and 0.3 parts of the catalyst 1,1-bis(tert-butylperoxide)-3,3,5-trimethylcyclohexane was added. After stirring, 2 parts of the curing agent dicyandiamide were added, and the mixture was uniformly stirred for 8 minutes to obtain the prepreg resin.

[0046] (2) The prepreg resin is coated on a continuous coating machine as a fixed weight resin film and mixed with 133g / m 2 HF30T fibers with uniform surface density and unidirectional arrangement were impregnated at a maximum impregnation temperature of 90° C. to obtain prepreg S3-1.

[0047] (3) Autoclave curing: gradually increase the temperature from room temperature to 120°C at 2°C / min, keep it at that temperature for 1 hour, then gradually increase the temperature to 180°C at 2°C / min and keep it at that temperature for 1.5 hours, and then gradually increase the temperature to 210°C at 2°C / min and keep it at that temperature for 2 hours. The laminate product S3-2 obtained under this curing process.

[0048] Example 4 This embodiment provides a highly heat-resistant self-toughening functional resin composition and a prepreg and laminate prepared therefrom.

[0049] (1) First, weigh and mix the modified ingredients according to their weight: multifunctional epoxy resin: 48 parts, special benzoxazine resin: 34.8 parts, flame retardant: 14 parts, catalyst: 0.2 parts, curing agent: 3 parts. Add 8 parts of Tactix 756 resin, 7 parts of ERISYS GA-240 resin, and 33 parts of Araldite MY9663 resin to a mixing kettle, heat to 85°C, stir thoroughly until the mixture is evenly mixed, and add the special benzoxazine resin. 34.8 parts of the mixture were stirred thoroughly until uniformly mixed, 10 parts of flame retardant ammonium polyphosphate (type II) and 4 parts of zinc borate were added, and the mixture was stirred thoroughly. The temperature was then lowered to 55°C, 0.2 parts of catalyst 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane were added, and the mixture was stirred thoroughly. Then, 3 parts of curing agent 2MZ-AZINE were added, and the mixture was stirred thoroughly for 8 minutes to obtain the prepreg resin d.

[0050] (2) The prepreg resin is coated on a continuous coating machine as a fixed weight resin film and mixed with 133g / m 2 HF30T fibers with uniform surface density and unidirectional arrangement were impregnated at a maximum impregnation temperature of 90° C. to obtain prepreg S4-1.

[0051] (3) Autoclave curing: gradually increase the temperature from room temperature to 120°C at 2°C / min, keep it at that temperature for 1 hour, then gradually increase the temperature to 180°C at 2°C / min and keep it at that temperature for 1.5 hours, and then gradually increase the temperature to 210°C at 2°C / min and keep it at that temperature for 2 hours. The laminate product S4-2 obtained under this curing process.

[0052] Example 5 This embodiment is basically the same as embodiment 1, except that in this embodiment, the structural formula of the special benzoxazine resin is .

[0053] Example 6 This embodiment is basically the same as embodiment 1, except that in this embodiment, the structural formula of the special benzoxazine resin is .

[0054] Comparative Example 1 This comparative example provides a conventional high-temperature resistant toughening resin composition and a prepreg and a laminate prepared therefrom.

[0055] (1) First, weigh and mix the modified ingredients according to their weight: 37 parts of multifunctional epoxy resin, 20 parts of special benzoxazine resin, 14 parts of flame retardant, 12 parts of thermoplastic toughening agent, and 17 parts of curing agent. Add 18 parts of Araldite MY0500 resin and 19 parts of Araldite MY721 resin to a mixing kettle, heat to 100°C, stir thoroughly until the mixture is uniform, add 12 parts of thermoplastic toughening agent PES, stir thoroughly to dissolve, cool to 85°C, and add special benzoxazine resin. 20 parts of the mixture were stirred thoroughly until uniformly mixed, 14 parts of aluminum hydroxide as a flame retardant were added, and the mixture was stirred thoroughly, then the temperature was lowered to 70° C., 17 parts of 4,4-DDS as a curing agent were added, and the mixture was stirred uniformly for 8 minutes to obtain the prepreg resin.

[0056] (2) The prepreg resin is coated on a continuous coating machine as a fixed weight resin film and mixed with 133g / m 2 HF30T fibers with uniform surface density and unidirectional arrangement were impregnated at a maximum impregnation temperature of 120° C. to obtain prepreg D1-1.

[0057] (3) Autoclave curing: gradually increase the temperature to 180°C at 2°C / min and keep it for 1.5 hours, then gradually increase the temperature to 210°C at 2°C / min and keep it for 2 hours. Laminated board product D1-2 was obtained under this curing process.

[0058] Comparative Example 2 This comparative example provides a conventional high-temperature resistant toughening resin composition and a prepreg and a laminate prepared therefrom.

[0059] (1) First, weigh and mix the modified ingredients according to their weight: 47 parts of multifunctional epoxy resin, 14 parts of flame retardant, 17 parts of thermoplastic toughening agent, and 22 parts of curing agent. Add 20 parts of Araldite MY0500 resin and 27 parts of Araldite MY721 resin to a mixing kettle, heat to 100°C, stir thoroughly until the mixture is uniform, add 17 parts of PES, stir thoroughly to dissolve, cool to 85°C, stir thoroughly until the mixture is uniform, add 10 parts of flame retardant ammonium polyphosphate (type II) and 4 parts of zinc borate, stir thoroughly, cool to 70°C, add 22 parts of curing agent 4,4-DDS, stir thoroughly for 8 minutes, and discharge to obtain the prepreg resin.

[0060] (2) The prepreg resin is coated on a continuous coating machine as a fixed weight resin film and mixed with 133g / m 2 HF30T fibers with uniform surface density and unidirectional arrangement were impregnated at a maximum impregnation temperature of 120° C. to obtain prepreg D2-1.

[0061] (3) Autoclave curing was performed by gradually increasing the temperature to 180°C at 2°C / min and holding the temperature for 1.5 h, and then gradually increasing the temperature to 210°C at 2°C / min and holding the temperature for 2 h. The laminate product D2-2 was obtained under this curing process.

[0062] Comparative Example 3 This comparative example is basically the same as Example 1, except that bisphenol A benzoxazine is used in this comparative example to replace the special benzoxazine resin in Example 1. The structural formula of bisphenol A benzoxazine is: , obtaining prepreg D3-1 and laminate product D3-2.

[0063] Comparative Example 4 This comparative example is basically the same as Example 1, except that diamine benzoxazine is used in this comparative example to replace the special benzoxazine resin in Example 1. The structural formula of diamine benzoxazine is , obtaining prepreg D4-1 and laminate product D4-2.

[0064] Comparative Example 5 This comparative example is basically the same as Example 1, except that the catalyst of Example 1 is omitted in this comparative example, and a prepreg D5-1 and a laminate product D5-2 are obtained.

[0065] Experimental example (1) In conjunction with the above-mentioned Examples and Comparative Examples, the properties of the prepregs in different Examples and Comparative Examples were tested. The degree of impregnation was determined using a qualitative method, where a larger number indicates a better degree of impregnation. The tack life of the prepregs at 25°C was tested according to the test standard HB7736.8. See Table 1 for the test results.

[0066] Table 1. Prepreg properties in different examples and comparative examples

[0067] The performance of the prepregs in Examples 1-6 and Comparative Examples 1-2 shows that the performance of the prepregs using the highly heat-resistant, self-toughening functional prepreg and its preparation method is significantly superior to that of the comparative examples. In terms of the stability of the prepreg itself, the tack life of the examples in Table 1 is significantly higher than that of comparative examples 1-2. This is because the comparative examples use the traditional high-temperature prepreg curing agent 4,4-DDS, which itself has poor room-temperature latency. Furthermore, to achieve a high degree of impregnation, the prepreg is heated and pressurized during the prepreg manufacturing process, using relatively extreme process conditions. This has a more adverse effect on the tack life of the prepreg itself, resulting in a tack life of only 7-9 days in the comparative examples. The use of a curing agent with superior latency in Examples 1-6 and Comparative Examples 3-5 significantly increases the tack life compared to the comparative examples.

[0068] (2) In combination with the above-mentioned embodiments and comparative examples, the mechanical properties of the laminates after the prepregs in different embodiments and comparative examples were tested. Please refer to Table 2 for the test methods and test results.

[0069] Table 2 Mechanical properties of laminates after curing of prepregs in different examples and comparative examples

[0070] The tensile performance data in Table 2 also shows that the tensile performance of Comparative Examples 1 and 2 is lower than that of the Examples. This is due to the performance degradation caused by friction and extrusion during the prepreg impregnation process during the manufacturing process, which leads to internal fiber breakage. The compression performance of the Examples in Table 2 is superior to that of Comparative Examples 1 and 2. This is mainly due to the introduction of the special epoxy resin, which undergoes ring-opening curing and cross-linking of the multifunctional resin during the curing process. After curing, the molecular cross-linked chains have more CO and CN bonds, and these bonds are regularly arranged to form a large number of intermolecular hydrogen bonds. This increases the rigidity of the cured sheet as a whole, thereby improving the compressive strength of the Examples. The plate-grade CAI in the embodiment is significantly better than that in comparative examples 1 to 5, mainly because the embodiment cleverly introduces a catalyst that can trigger a double bond reaction and a special epoxy resin. The optimized design of the two ensures that it can achieve "stage-by-stage" curing. Before other reactive groups fail to react, chain growth is achieved through low-temperature insulation, effectively adding flexible segments to the rigid main chain, ensuring high toughness while ensuring rigidity, achieving ultra-high post-impact compression (CAI) performance, and ensuring the complete curing of the main chain (back-end curing). While ensuring "high rigidity and high toughness", the glass transition temperature (Tg) of the relevant plate grade is basically equivalent to that of the comparative example.

[0071] (3) In combination with the above-mentioned embodiments and comparative examples, the flame retardancy of the laminates in the different embodiments and comparative examples was tested (using the 2010 FTP test specification, where the most stringent requirements are smoke density ≤ 200 and surface burning energy ≤ 4 kW). Please refer to Table 3 for the test methods and test results.

[0072] Table 3. Flame retardant properties of laminates in different examples and comparative examples

[0073] Table 3 shows that Examples 1-6 exhibit significantly better flame retardancy than Comparative Examples 1-2. This is primarily due to the incorporation of a specialty epoxy resin and a phosphorus-based flame retardant. During flame combustion, the phosphorus-based flame retardant induces dehydration and carbonization of the cured crosslinked product of the multifunctional resin and specialty benzoxazine resin in these Examples, reducing the production of small cracked molecules and thus achieving low smoke and low combustion performance. While the flame retardancy of Comparative Examples 3-5, after incorporating conventional benzoxazine resin and omitting the catalyst of the present invention, is significantly improved compared to Comparative Examples 1-2, combined with the compression after impact (CAI) performance shown in Table 2, the Examples exhibit superior overall performance to Comparative Examples 3-5.

[0074] In summary, the present invention provides a high-heat-resistant self-toughening functional resin composition, which aims to solve the difficulties in the industry, especially the difficulties encountered by high-rigidity and high-toughness resins in the application process. The core lies in the precise definition of the raw materials, especially by designing the structure of the special benzoxazine resin - selecting a group containing an olefin carbon-carbon double bond on one side as a substituent of the benzoxazine resin, so that the resin can undergo a double bond opening addition reaction under the action of a catalyst in the subsequent curing stage, thereby forming a chain copolymer prepolymer with a tough structure. To achieve this effect, only R1 or R2 in this application contains an olefin, so as to ensure that the special benzoxazine resin can be connected one by one through the olefin to form a long-chain flexible compound, thereby effectively avoiding the situation where a macrocyclic structure may appear when R1 and R2 contain olefins at the same time. At the same time, since the special benzoxazine resin itself contains a benzene ring structure, it can also undergo a ring-opening curing reaction with a resin containing an epoxy multifunctional group. Therefore, the high-heat-resistant self-toughening functional resin composition provided by the present invention can simultaneously achieve properties such as self-toughening, high heat resistance and high flame retardancy during the curing process.

[0075] The laminate provided by the present invention starts from the molecular structure design and introduces a "step-by-step" reaction cross-linking point. By controlling the curing temperature, it can not only achieve the synergy of self-toughening, high heat resistance and high flame retardancy, but also complete the self-toughening of the cured main resin by orderly regulating the curing stage of the matrix resin. By optimizing the intermolecular force of the matrix resin and the cross-linking point density, the high heat resistance and high flame retardancy are unified, thereby avoiding the disadvantages of improving the composite toughness by adding a high molecular weight thermoplastic reinforcement. The problem encountered by the uncured resin in the prepreg preparation process can be fully reduced. The difficulty of the back-end prepreg preparation can be fully reduced. There is no need to force the high temperature and high pressure mode to solve the problem of insufficient impregnation of the prepreg. At the same time, the reduction in the difficulty of the manufacturing process also reduces the loss of fibers in the prepreg manufacturing process, reduces the manufacturing cost and process controllability, and the viscosity life of the high temperature curing prepreg system at room temperature of 25 ° C is as high as 28 days. At the same time, through clever design, the toughness performance of the plate after the prepreg is cured is fully improved, while ensuring stiffness and retaining toughness. In addition, the flame retardant and fireproof performance has also been substantially improved, which can achieve the most stringent combustion and smoke requirements in the fire resistance test requirements (FTP rules) issued by the International Maritime Organization.

[0076] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A high heat-resistant self-toughening functional resin composition, characterized in that: The raw materials include, by weight, 30-60 parts of epoxy multifunctional resin, 30-50 parts of special benzoxazine resin, 10-18 parts of flame retardant, 0.1-1 parts of catalyst and 1-5 parts of curing agent; The special benzoxazine resin has the following structural characteristics: ， Wherein, either R1 or R2 is H, and the other is a group containing an olefinic carbon-carbon double bond.

2. The high heat-resistant self-toughening functional resin composition according to claim 1, characterized in that The group containing an olefin carbon-carbon double bond is selected from one of the following groups: , , , , , , , , , , , , , , where * indicates the attachment site.

3. The high heat-resistant self-toughening functional resin composition according to claim 1, characterized in that The epoxy multifunctional resin is one or more of Araldite MY0500, Araldite MY0600, Tactix 742, Araldite MY720, Araldite MY721, Araldite XB9721, Araldite MY9663, ERISYS GA-240, and Tactix 756; And / or, the flame retardant includes one or more of organic phosphate flame retardants, polyphosphate amine (type II), melamine urate, organic phosphonate, polyphosphate melamine, organic montmorillonite, borate and silicate.

4. The high heat-resistant self-toughening functional resin composition according to claim 1, characterized in that The catalyst comprises one or more of trioctylmethylammonium persulfate, tert-butyl hydroperoxide, tert-amyl peroxy-2-ethylhexanoate (TAPO), diisopropylbenzene peroxide (DCP), di-tert-butyl peroxide (DTBP), isopropylbenzene hydroperoxide, tert-butyl peroxybenzoate (TBPB), 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and a,a'-bis(tert-butylperoxy)diisopropylbenzene.

5. The high heat-resistant self-toughening functional resin composition according to claim 1, characterized in that The curing agent is one or more of the following structures: 。 6. A prepreg, characterized in that The prepreg comprises continuous fibers and the high heat-resistant self-toughening functional resin composition according to any one of claims 1 to 5. The high heat-resistant self-toughening functional resin composition is coated to form a resin film, which is then impregnated with the continuous fibers to obtain the prepreg.

7. The prepreg according to claim 6, characterized in that The surface density of the continuous fiber ranges from 50 to 300 g / m 2 .

8. A laminated board, characterized in that: It comprises the prepreg according to any one of claims 6 to 7.

9. The laminate according to claim 8, characterized in that The preparation method of the laminate comprises performing step-by-step curing on the prepreg, wherein the step-by-step curing comprises firstly performing a first-stage curing at 100-120° C., then performing a second-stage curing at 160-180° C., and finally performing a third-stage curing at 200-220° C.

10. The laminate according to claim 9, characterized in that The holding time of the first stage curing is 0.5-1.5h, and the heating rate is 1-3℃ / min; And / or, the second stage curing holding time is 1-2 hours, and the heating rate is 1-3°C / min; And / or, the holding time of the third stage curing is 1.5-2.5 hours, and the heating rate is 1-3°C / min.

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