A uv light-cured epoxy prepreg and a production process thereof

Abstract

This invention belongs to the field of epoxy prepreg technology, and particularly relates to a UV-curable epoxy prepreg and its production process. This invention uses epoxy resin as a matrix, resulting in low initial viscosity, and produces a UV-curable epoxy prepreg through a wet prepreg process. This results in low manufacturing costs. The epoxy resin system is modified and thickened using a polyamine compound containing amino groups, increasing the prepreg resin viscosity to a peelable state. The prepreg of this invention can be fully cured by UV irradiation for 20 minutes, exhibiting high mechanical strength and peel strength after curing, making it suitable for applications such as interior wall repair and pipe repair with high environmental protection requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fiber-reinforced light-cured resin composites, in particular to a UV light-cured epoxy prepreg and a production process thereof. BACKGROUND

[0002] With the rapid development of the country, various infrastructures are increasingly improved. With the passage of time, infrastructures are long-term exposed to wind and rain, impact damage, resulting in corrosion, cracking, collapse and other problems. There is an urgent need for a material that can be quickly cured and has high mechanical strength to quickly repair and reinforce. Light-cured prepreg can meet many repair requirements due to its fast curing, simple operation, low cost, high curing mechanical strength and other advantages.

[0003] Currently, light-cured prepregs on the market are mostly made of unsaturated polyester resin and vinyl resin as the resin matrix for pre-impregnation. However, due to problems such as VOC emissions, low mechanical strength, poor corrosion resistance, and the like, they cannot meet the specific use requirements of certain scenarios. In addition, the curing is affected by oxygen inhibition, and there is no post-curing phenomenon, which can easily lead to incomplete surface curing and cause a decrease in material performance. The light-cured mechanical strength of the epoxy resin matrix is high, the corrosion resistance is excellent, it is not affected by oxygen, and after the light is stopped, it can still continue to initiate polymerization and crosslinking for post-curing. The curing thickness can reach more than 10 mm, and the like. It can meet the requirements that traditional light-cured prepregs cannot meet under certain conditions.

[0004] Epoxy prepregs are generally manufactured by wet and dry processes. In order to meet the pre-impregnation requirements at room temperature, a large amount of solvent is often added to ensure that the resin viscosity is low enough to fully impregnate the fibers. Then, the solvent is removed by drying to achieve a tearable film state, causing air pollution. Dry pre-impregnation is a two-step pre-impregnation process by hot melting, which has high production cost and long production cycle. Therefore, it is necessary to develop a solvent-free, low initial viscosity, and self-thickening wet pre-impregnated light-cured epoxy prepreg. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the present application provides a UV light-cured epoxy prepreg and a production process thereof, which obtains a high-strength, high-corrosion-resistant, pollution-free, self-thickening light-cured epoxy prepreg, which can be used in pipeline repair, tank lining repair, pile protection and other fields.

[0006] One of the purposes of the present application is to provide a UV light-cured epoxy prepreg, comprising 50-65% of fiber reinforced material by weight and 35-50% of thickenable UV light-cured epoxy resin composition by weight, the thickenable UV light-cured epoxy resin composition comprising an epoxy resin composition and an amino active hydrogen-containing epoxy thickener, and the molar ratio of epoxy groups in the epoxy resin composition to amino active hydrogen in the epoxy thickener is 100:12-100:40.

[0007] The fiber reinforced material is at least one of continuous glass fiber square cloth, continuous glass fiber felt, non-woven glass fiber felt and glass fiber woven cloth mixed fabric. Preferably, the surface density of the continuous glass fiber square cloth is 400-600 g / m 2 ; the surface density of the continuous glass fiber felt is 100-400 g / m 2 ; the surface density of the non-woven glass fiber felt and glass fiber woven cloth mixed fabric is 400-800 g / m 2 , the fiber length of the non-woven glass fiber felt is 15-50 mm, and the weight ratio of the non-woven glass fiber felt to the glass fiber woven cloth is 1-4:6-9.

[0008] The epoxy resin composition is composed of 58-70% of epoxy resin by weight, 29-40% of cationic active diluent, and 1-2% of cationic photoinitiator.

[0009] The cationic photoinitiator is selected from cationic photoinitiators with high reaction activity at a wavelength of 250-400 nm, preferably diaryl iodonium salt and triaryl sulfonium salt. The cationic photoinitiator is selected from at least one of PAG101 (bis(4-tert-butylphenyl) iodonium hexafluorophosphate), 6976 (bis(4-(diphenyl sulfonium) phenyl) sulfide-bishexafluoroantimonate), UV6992 (diphenyl-(4-phenylsulfanyl) phenyl sulfonium hexafluorophosphate), PAG-002 (diphenyl-(4-phenylsulfanyl) phenyl sulfonium hexafluoroantimonate).

[0010] The cationic active diluent is at least one of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl acid active diluent, bis((3,4-epoxycyclohexyl) methyl) adipate active diluent, and epoxy soybean oil acrylate active diluent.

[0011] The epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin.

[0012] The initial viscosity of the epoxy resin composition is 3000-5600 cps.

[0013] The amino active hydrogen-containing epoxy thickening agent is at least one of monoamine or polyamine containing one or more primary amino or secondary amino groups, which can be at least one of aliphatic amine, alicyclic amine, aromatic amine, polyether amine, polyamide, and is further preferably isophorone diamine, polyether amine D230, etc.

[0014] Another object of the present application is to provide a UV photocuring epoxy prepreg production process, comprising the following steps:

[0015] a. Weigh 58-70% of epoxy resin, 29-40% of cationic active diluent, and 1-2% of cationic photoinitiator by weight percentage, and mix them thoroughly under light-proof condition with stirring speed of 300-800 rpm to obtain an epoxy resin composition with initial viscosity of 3000-5600 cps, which is stored for later use;

[0016] b. Mix the epoxy resin composition with the amino active hydrogen-containing epoxy thickening agent at a certain proportion with high-speed stirring, wherein the molar ratio of epoxy groups in the epoxy resin composition to the amino active hydrogen in the epoxy thickening agent is 100:12-100:40, and mix them uniformly under light-proof condition to obtain a thickenable UV photocuring epoxy resin composition;

[0017] c. Coat the thickenable UV photocuring epoxy resin composition uniformly on black upper and lower carrier films to form an epoxy resin film with thickness of 0.15-0.3 mm;

[0018] d. Compound the fiber reinforced material with the above epoxy resin film, and perform extrusion impregnation and exhaust with extrusion pressure of 0.1-0.2 MPa to make the UV photocuring epoxy resin composition impregnate the fiber reinforced material fully, and then close the light and wind up for packaging;

[0019] e. Age the UV photocuring epoxy prepreg wound and packaged for 10-40 hrs at 30-55℃ to complete the aging treatment.

[0020] The viscosity of the photocuring epoxy resin composition after aging treatment is 2000-50000 Pa.s at 25℃.

[0021] The present application has the following advantages: the present application uses epoxy resin as the matrix with low initial viscosity, and the UV photocuring epoxy prepreg is prepared by wet pre-impregnation, which has low manufacturing cost; the polyamine compound containing amino groups is used as the epoxy thickening agent to modify and thicken the epoxy resin system, so that the viscosity of the prepreg resin is increased to reach the tearable film state; the epoxy resin and cationic photoinitiator are used to avoid the incomplete curing caused by oxygen inhibition of free radical photoinitiator.

[0022] The light-cured epoxy prepreg of the present application is easy to separate the carrier film, the epoxy resin is not sticky and is transferred, and is suitable for prepreg laying operation. The prepreg can be completely cured by irradiating 250-400 nm wavelength ultraviolet light for 15-20 min. The cured plate thickness can reach more than 10 mm, and the cured product has good mechanical properties, the tensile strength reaches more than 350 Mpa, the tensile modulus reaches more than 15 Gpa, the bending strength reaches more than 400 Mpa, the bending modulus reaches more than 20 Gpa, and the interlaminar shear strength is greater than 50 MPa. It has the characteristics of fast curing, high bonding strength, high peeling strength and high mechanical strength.

[0023] The prepreg of the present application is suitable for the fields of high environmental protection requirement interior decoration wall repair and pipeline repair. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Structure diagram of the iron sheet funnel with ball valve.

[0025] In the figure: 1, funnel body, 2, ball valve, 3, iron sheet cover. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] One of the purposes of the present application is to provide a UV light-cured epoxy prepreg, which comprises 50-65% of fiber reinforced material by weight and 35-50% of thickenable UV light-cured epoxy resin composition by weight, the thickenable UV light-cured epoxy resin composition comprises an epoxy resin composition and an epoxy thickener containing amino active hydrogen, and the molar ratio of epoxy groups in the epoxy resin composition to amino active hydrogen in the epoxy thickener is 100:12-100:40.

[0028] The fiber reinforced material is at least one of continuous glass fiber square cloth, continuous glass fiber felt, non-woven glass fiber felt and glass fiber woven cloth mixed fabric. Preferably, the areal density of the continuous glass fiber square cloth is 400-600 g / m 2 ; the areal density of the continuous glass fiber felt is 100-400 g / m 2 ; the areal density of the non-woven glass fiber felt and glass fiber woven cloth mixed fabric is 400-800 g / m 2 , the fiber length of the non-woven glass fiber felt is 15-50 mm, and the weight ratio of the non-woven glass fiber felt to the glass fiber woven cloth is 1-4:6-9.

[0029] The epoxy resin composition is composed of 58-70% of epoxy resin, 29-40% of cationic active diluent, 1-2% of cationic photoinitiator by weight percentage.

[0030] The cationic photoinitiator is selected from cationic photoinitiators with high reaction activity at ultraviolet wavelength of 250-400 nm, preferably diaryliodonium salt, triarylsulfonium salt. The cationic photoinitiator is selected from at least one of PAG101 (bis(4-tert-butylphenyl) iodonium hexafluorophosphate), 6976 (bis(4-(diphenylsulfonium) phenyl) sulfide-bishexafluoroantimonate), UV6992 (diphenyl-(4-phenylsulfanyl) phenylsulfonium hexafluorophosphate), PAG-002 (diphenyl-(4-phenylsulfanyl) phenylsulfonium hexafluoroantimonate).

[0031] The cationic active diluent is at least one of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl carboxylate active diluent, bis((3,4-epoxycyclohexyl) methyl) adipate active diluent, epoxy soybean oil acrylate active diluent.

[0032] The epoxy resin is bisphenol A epoxy resin, bisphenol F epoxy resin.

[0033] The initial viscosity of the epoxy resin composition is 3000-5600 cps.

[0034] The epoxy thickener containing active hydrogen amino groups is at least one of monoamine or polyamine containing one or more primary amino or secondary amino groups, which can be at least one of aliphatic amine, alicyclic amine, aromatic amine, polyether amine, polyamide, and is further preferably isophorone diamine, polyether amine D230, etc.

[0035] Another object of the present application is to provide a UV photocuring epoxy prepreg production process, comprising the following steps:

[0036] a. The epoxy resin 58-70%, cationic active diluent 29-40%, cationic photoinitiator 1-2% are weighed by weight percentage and added to the resin mixer for stirring and fully mixed, the stirring speed is 300-800 rpm, the resin reactor is subjected to light shielding treatment, and after the reaction is completed, it is stored in the resin storage tank, to obtain an epoxy resin composition with an initial viscosity of 3000-5600 cps;

[0037] b. The epoxy resin composition and the epoxy thickener containing amino active hydrogen are proportionally pumped into a high-speed stirring mixer in series through resin feed pump and thickener feed pump, wherein the molar ratio of epoxy groups in the epoxy resin composition to amino active hydrogen in the epoxy thickener is 100:12-100:40, and the mixture is uniformly mixed to obtain a thickenable UV photocurable epoxy resin composition, which is then introduced into a resin sheet funnel through a light-shielded resin guide groove, and the resin content in the groove is controlled through a funnel ball valve; an iron sheet cover with the same size as the groove is installed below the funnel ball valve to cover the groove to achieve light shielding, and an ultraviolet light-proof film is laid on the guide groove;

[0038] c. The thickenable UV photocurable epoxy resin composition introduced from the iron sheet funnel is uniformly coated on a black carrier film by a resin groove scraper to form an epoxy resin film with a thickness of 0.15-0.3 mm;

[0039] d. The fiber reinforced material is combined with the epoxy resin film, extruded and infiltrated through a compaction area, and the extrusion pressure is 0.1-0.2 MPa, so that the UV photocurable epoxy resin composition fully infiltrates the fiber reinforced material, and then the light is closed for winding and packaging;

[0040] e. The UV photocurable epoxy prepreg after winding and packaging is cured in an oven, and the curing is completed at 30-55°C for 10-40 hrs.

[0041] The viscosity of the photocurable epoxy resin composition after curing treatment is 2000-50000 Pa.s at 25°C.

[0042] The UV photocurable epoxy prepreg is easy to separate the carrier film, the epoxy resin is not sticky to transfer, and is suitable for prepreg laying operation.

[0043] Example 1:

[0044] The UV photocurable epoxy prepreg of the present example comprises 60% by weight of continuous glass fiber square cloth (the area density is 400 g / m 2 ), and 40% by weight of the thickenable UV photocurable epoxy resin composition.

[0045] The thickenable UV photocurable epoxy resin composition comprises an epoxy resin composition and an epoxy thickener containing amino active hydrogen, and the weight ratio of the epoxy resin composition to the epoxy thickener is 100:5.4, and the epoxy thickener is isophorone diamine; the epoxy resin composition comprises 70 parts of bisphenol A epoxy resin, 2 parts of cationic photoinitiator UV6992 diphenyl-(4-phenylthio) phenyl sulfonium hexafluorophosphate, and 30 parts of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl acid active diluent.

[0046] The production process of the UV-cured epoxy prepreg above comprises the following steps:

[0047] a. 70 parts of bisphenol A epoxy resin, 30 parts of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl acid active diluent, and 2 parts of UV6992 photoinitiator are added to a double-shaft resin mixer for stirring at room temperature, the stirring speed is 400 rpm, and the stirring time is 30 min to obtain an epoxy resin composition, which is stored in a resin storage tank. The initial viscosity of the epoxy composition at 25°C is tested according to the standard GB / T22314-2008 by using a Brookfield DVS+ rotary viscometer, and the initial viscosity is 5218 cps;

[0048] b. The epoxy resin composition and isophorone diamine are mixed by a series mixer at a weight ratio of 100:5.4, stirred at room temperature at a high speed, the stirring speed is 800 rpm, and the stirring time is 5 min to obtain a UV-cured epoxy resin composition capable of rapid thickening;

[0049] c. The resin paste uniformly mixed in step b is introduced into a resin sheet metal funnel through a light-shielded glue channel, and the resin content in the glue channel is controlled through a funnel ball valve. The sheet metal funnel comprises a funnel body 1, a glue channel is formed in the funnel body 1, an ultraviolet light-proof film is laid on the glue channel for introducing the resin paste from the mixer into the funnel body 1, a ball valve 2 is installed below the funnel body 1 for controlling the flow of the resin paste, and an iron sheet cover 3 is sleeved below the funnel body 1 to ensure that the resin paste is in a light-shielded state after being introduced into the next container. The structure is shown in Figure 1 .

[0050] d. The epoxy resin composition introduced from the sheet metal funnel is uniformly coated on the black upper and lower carrier films by using a scraper to form an epoxy resin film with a thickness of 0.25-0.30 mm;

[0051] e. The continuous glass fiber square cloth with a surface density of 400 g / m 2 The continuous glass fiber square cloth is placed on the lower epoxy resin film, and then the upper epoxy resin film is covered on the surface of the continuous glass fiber square cloth. After extrusion and degassing, the epoxy resin paste is fully impregnated into the glass fiber cloth to form a UV-cured epoxy prepreg, and then the UV-cured epoxy prepreg is wound at a speed of 50 m / vol to be packaged.

[0052] f. The packaged UV-cured epoxy prepreg is cured at 50°C for 10 hrs to thicken the epoxy resin, and an epoxy prepreg with easy-to-tear film is obtained.

[0053] Example 2:

[0054] The UV-cured epoxy prepreg of the present embodiment comprises 65% of continuous glass fiber felt (with a surface density of 200 g / m2 ), a UV-curable epoxy resin composition with a thickening property;

[0055] The UV-curable epoxy resin composition with a thickening property comprises an epoxy resin composition and an epoxy thickening agent containing active hydrogen of amino group, and the weight ratio of the epoxy resin composition to the epoxy thickening agent is 100:8, wherein the epoxy thickening agent is polyetheramine D230; the epoxy resin composition comprises 60 parts of bisphenol A epoxy resin and 40 parts of bis((3,4-epoxycyclohexyl)methyl)hexanedioate active diluent, and 2 parts of cationic photoinitiator PAG-002 diphenyl-(4-phenylthio)phenyl sulfonium hexafluoroantimonate.

[0056] The production process of the UV-curable epoxy prepreg comprises the following steps:

[0057] a. 60 parts of bisphenol A epoxy resin, 40 parts of bis((3,4-epoxycyclohexyl)methyl)hexanedioate active diluent, and 2 parts of PAG-002 photoinitiator are added into a double-shaft resin mixer for stirring at room temperature, the stirring speed is 400 rpm, and the stirring time is 40 min, to obtain a UV-curable epoxy resin composition which is stored in a resin storage tank, and the initial viscosity of the epoxy composition at 25°C is tested by using a Brookfield DVS+ rotary viscometer according to the standard GB / T22314-2008, and the initial viscosity is 3218 cps;

[0058] b. The UV-curable epoxy resin composition and D230 are mixed by a series mixer at a weight ratio of 100:8, and stirred at room temperature at a high speed, the stirring speed is 800 rpm, and the stirring time is 5 min, to obtain a UV-curable epoxy resin composition with a rapid thickening property;

[0059] c. The resin paste uniformly mixed in step b is introduced into a resin sheet metal funnel (as shown in Figure 1 ) through a light-shielded glue channel, and the resin content in the glue channel is controlled by a funnel ball valve;

[0060] d. The epoxy resin composition introduced from the sheet metal funnel is uniformly coated on the black upper and lower carrier films by using a scraper to form an epoxy resin film with a thickness of 0.17-0.25 mm;

[0061] e. The epoxy resin film is covered on the surface of the continuous glass fiber mat with a surface density of 200 g / m 2 The continuous glass fiber mat is placed on the lower epoxy resin film, and then the upper epoxy resin film is covered on the surface of the continuous glass fiber mat, and the epoxy resin paste is fully impregnated into the glass fiber mat to form a UV-curable epoxy prepreg through extrusion and exhaust, the extrusion pressure is 0.1 MPa, and then the UV-curable epoxy prepreg is wound in a roll with a length of 50 m for packaging.

[0062] f. The packaged photocured epoxy prepreg is cured in an oven at 45℃ for 15 hrs to thicken the epoxy resin and obtain an epoxy prepreg with easy-to-tear film.

[0063] Example 3:

[0064] The UV photocured epoxy prepreg of the present example comprises 50% by weight of a non-woven glass felt and woven glass cloth mixed fabric (the areal density is 600 g / m 2 ) and 50% by weight of a thickenable photocured epoxy resin composition, wherein the mass ratio of the fiber cloth (i.e. the woven glass cloth) to the fiber felt (i.e. the non-woven glass felt) in the non-woven glass felt and woven glass cloth mixed fabric is 7:3, and the fiber length of the glass felt is 15-50 mm.

[0065] The thickenable UV photocured epoxy resin composition comprises an epoxy resin composition and an epoxy thickener containing active hydrogen amino groups, and the weight ratio of the epoxy resin composition to the epoxy thickener is 100:8, wherein the epoxy thickener is polyetheramine D230; the epoxy resin composition comprises 70 parts of bisphenol A epoxy resin, 30 parts of bis((3,4-epoxycyclohexyl)methyl)hexanedioate active diluent, and 1.5 parts of cationic photoinitiator 6976 bis(4-(diphenyl sulfonio)phenyl) sulfide-bis-hexafluoroantimonate.

[0066] The production process of the UV photocured epoxy prepreg comprises the following steps:

[0067] a. 70 parts of bisphenol A epoxy resin, 30 parts of bis((3,4-epoxycyclohexyl)methyl)hexanedioate active diluent, and 1.5 parts of 6976 photoinitiator are added to a double-shaft resin mixer for stirring at room temperature, the stirring speed is 400 rpm, and the stirring time is 40 min to obtain a photocured epoxy resin composition, which is stored in a resin storage tank, and the initial viscosity of the epoxy composition at 25℃ is tested by using a Brookfield DVS+ rotary viscometer according to the standard GB / T22314-2008, and the initial viscosity is 5563 cps;

[0068] b. The photocured epoxy resin composition and D230 are mixed by a series mixer at a weight ratio of 100:8, high-speed stirring at room temperature, the stirring speed is 800 rpm, and the stirring time is 4 min to obtain a UV photocured epoxy resin composition that can be quickly thickened;

[0069] c. The resin paste uniformly mixed in step b is introduced into a resin sheet funnel (as shown in Figure 1 ) through a light-shielded glue channel, and the resin content in the glue channel is controlled through a funnel ball valve;

[0070] d. Use a scraper to evenly coat the epoxy resin composition drawn from the sheet metal funnel onto the upper and lower black support films to form an epoxy resin film with a thickness of 0.4~0.5mm;

[0071] e. A surface density of 600 g / m³ 2 The non-woven fiberglass felt and fiberglass woven fabric mixture is laid on the lower epoxy resin film, and then the upper epoxy resin film is covered on the surface of the non-woven fiberglass felt and fiberglass woven fabric mixture. After extrusion and degassing, with an extrusion pressure of 0.2 MPa, the epoxy resin paste is fully impregnated into the mixture to form a light-cured epoxy prepreg. Then, it is wound up in 50m rolls and packaged.

[0072] f. The packaged UV-cured epoxy prepreg is cured in a 45°C oven for 15 hours to thicken the epoxy resin and obtain an epoxy prepreg with an easy-tear film.

[0073] Example 4:

[0074] The UV-curable epoxy prepreg in this embodiment includes 55% by weight of continuous glass fiber woven fabric (area density of 600 g / m²). 2 A thickening, light-curable epoxy resin composition comprising 45% by weight;

[0075] The above-mentioned thickening UV-curable epoxy resin composition includes an epoxy resin composition and an epoxy thickener containing amino active hydrogen, wherein the weight ratio of epoxy resin composition to epoxy thickener is 100:8, wherein the epoxy resin thickener is polyetheramine D230, and the epoxy resin composition includes 70 parts of bisphenol A epoxy resin, 30 parts of epoxy soybean oil acrylate reactive diluent, and 1.5 parts of cationic photoinitiator selected from PAG101 bis(4-tert-butylphenyl)iodonium hexafluorophosphate.

[0076] The production process of the above-mentioned UV-curable epoxy prepreg includes the following steps:

[0077] a. Add 70 parts of bisphenol A epoxy resin, 30 parts of epoxy soybean oil acrylate reactive diluent, and 1.5 parts of PAG101 photoinitiator to a biaxial resin mixer and stir at room temperature at a speed of 400 rpm for 50 min to obtain a photocurable epoxy resin composition. Store the composition in a resin storage tank and test the initial viscosity of the epoxy composition at 25°C using a Bollerfeld DVS+ rotational viscometer according to standard GB / T22314-2008. The initial viscosity is 4189 cps.

[0078] b. The UV-curable epoxy resin composition and D230 are mixed at a weight ratio of 100:8 using a series mixer. The mixture is stirred at high speed at room temperature for 800 rpm for 5 minutes to obtain a UV-curable epoxy resin composition that can be rapidly thickened.

[0079] c. While shielding the light, guide the well-mixed resin paste from step b into a resin funnel (e.g., a resin sheet funnel). Figure 1 As shown in the figure, the resin content in the glue tank is simultaneously controlled by a funnel ball valve;

[0080] d. Use a scraper to evenly coat the epoxy resin composition drawn from the sheet metal funnel onto the upper and lower black support films to form an epoxy resin film with a thickness of 0.4~0.5mm;

[0081] e. A surface density of 600 g / m³ 2 The continuous glass fiber woven fabric is laid on the lower epoxy resin film, and then the upper epoxy resin film is covered on the surface of the continuous glass fiber woven fabric. After extrusion and degassing, the extrusion pressure is 0.2MPa, so that the epoxy resin paste fully impregnates the glass cloth to form a light-cured epoxy prepreg. Then it is wound up in 50m rolls and packaged.

[0082] f. The packaged UV-cured epoxy prepreg is cured in a 45°C oven for 15 hours to thicken the epoxy resin and obtain an epoxy prepreg with an easy-tear film.

[0083] The UV-curable epoxy prepregs of Examples 1-4 were cured and molded for mechanical property testing. The curing process included the following steps:

[0084] 1. Cut the cured prepreg into sheets of the same size as required, each sheet being 25mm*25mm; wherein the number of sheets cut in Examples 1-4 are 6, 12, 4, and 4 respectively;

[0085] 2. Lay the prepreg sheets of the same size in sequence according to the number of cut pieces, and use a scraper to remove air and flatten them each time;

[0086] 3. The prepregs of each embodiment were irradiated with a UV lamp to obtain prepreg cured sheets; wherein, the irradiation conditions for Example 1 were: irradiation with a 500W 320nm UV lamp for 20 minutes; the irradiation conditions for Example 2 were: irradiation with a 500W 340nm UV lamp for 20 minutes; the irradiation conditions for Example 3 were: irradiation with a 500W 320nm UV lamp for 20 minutes; and the irradiation conditions for Example 4 were: irradiation with a 500W 280nm UV lamp for 15 minutes.

[0087] 4. Cut the test specimens into tensile and bending test strips according to the test standard requirements and conduct mechanical tests.

[0088] The methods and standards for the above mechanical tests are as follows: Based on the GB / T 1446-2005 standard, the mechanical properties of composite materials prepared from UV-cured prepregs were tested using an electronic universal tensile testing machine. Tensile properties were tested according to the GB / T 1447-2005 standard, including tensile strength and tensile modulus; flexural properties were tested according to the GB / T 1449-2005 standard, including flexural strength and flexural modulus; and interlaminar shear strength was tested according to the GB / T 3355-2014 standard. The obtained data are shown in Table 1.

[0089] The tensile strength of the substrates bonded by the photocurable epoxy prepregs of Examples 1-4 was tested, including the following steps:

[0090] 1. Prepare two aluminum alloy plates, each 100mm long, 25mm wide, and 2.5mm thick. Use 150-grit sandpaper to mechanically sand the first 12.5mm section for later use.

[0091] 2. Cut the cured prepreg from Examples 1-4 into 25mm*25mm prepreg sheets, and use a scraper to remove air and flatten them during installation; the quantities cut are 6, 12, 4, and 4 sheets respectively.

[0092] 3. Grind the first ends of the two aluminum alloy plates together, and then attach the prepreg sheet laid in Examples 1-4 to the joint to obtain a pre-cured repair sheet;

[0093] 4. The above-mentioned repair pieces were irradiated with a UV lamp to obtain sample pieces. The irradiation conditions for Example 1 were: irradiation with a 500W 320nm UV lamp for 20 minutes; the irradiation conditions for Example 2 were: irradiation with a 500W 340nm UV lamp for 20 minutes; the irradiation conditions for Example 3 were: irradiation with a 500W 320nm UV lamp for 20 minutes; and the irradiation conditions for Example 4 were: irradiation with a 500W 280nm UV lamp for 15 minutes.

[0094] 5. The shear strength was tested according to GB / T3355-2014 standard, and the data obtained are shown in Table 1.

[0095] Table 1 Mechanical properties and repair test data of prepreg cured and molded

[0096]

[0097] As can be seen from the data in Table 1, the prepreg obtained by the present invention has high mechanical strength, with an interlayer shear strength greater than 55 MPa, and has a very high bonding strength to the adherend, with a shear strength greater than 17 MPa.

[0098] The foregoing detailed examples of the present invention are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A UV-curable epoxy prepreg, characterized in that: The composition comprises 50-65% by weight of fiber-reinforcing material and 35-50% by weight of a thicker UV-curable epoxy resin composition, wherein the thicker UV-curable epoxy resin composition comprises an epoxy resin composition and an epoxy thickener containing amino active hydrogen, and the molar ratio of epoxy groups in the epoxy resin composition to amino active hydrogen in the epoxy thickener is 100:12 to 100:

40. The epoxy resin composition comprises 58-70% by weight of epoxy resin, 29-40% by weight of cationic reactive diluent, and 1-2% by weight of cationic photoinitiator; The epoxy thickener containing amino active hydrogen is at least one of a monoamine or polyamine containing a primary or secondary amino group. The initial viscosity of the epoxy resin composition is 3000-5600 cps; after curing treatment, the viscosity at 25°C is 2000-50000 Pa·s. The cationic photoinitiator is selected from at least one of PAG101, 6976, UV6992, and PAG-002; the cationic reactive diluent is at least one of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylic acid reactive diluent, bis((3,4-epoxycyclohexyl)methyl)adipate reactive diluent, and epoxidized soybean oil acrylate reactive diluent; the epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin. The fiber reinforcement material is at least one of continuous glass fiber woven fabric, continuous glass fiber mat, and a mixed fabric of non-woven glass fiber mat and glass fiber woven fabric. The surface density of the continuous glass fiber woven fabric is 400~600 g / m². 2 The surface density of continuous glass fiber mat is 100~400 g / m³. 2 The areal density of the non-woven fiberglass mat and fiberglass woven fabric blend is 400~800 g / m². 2 The non-woven fiberglass felt has a fiber length of 15~50mm, and the weight ratio of non-woven fiberglass felt to fiberglass woven fabric is 1~4:6~9.

2. The production process of UV-curable epoxy prepreg according to claim 1, characterized in that, Includes the following steps: a. Weigh 58-70% epoxy resin, 29-40% cationic reactive diluent, and 1-2% cationic photoinitiator by weight percentage, stir thoroughly under light-protected conditions to obtain an epoxy resin composition with an initial viscosity of 3000-5600 cps, and store for later use. b. Mix the epoxy resin composition with an epoxy thickener containing amino active hydrogen in a certain proportion and stir at high speed. The molar ratio of epoxy groups in the epoxy resin composition to amino active hydrogen in the epoxy thickener is 100:12~100:

40. Mix evenly under light-protected conditions to obtain a thickening UV-curable epoxy resin composition. c. The thickening UV-curable epoxy resin composition is uniformly coated onto the black upper and lower support films to form an epoxy resin film with a thickness of 0.15-0.3 mm. d. The fiber-reinforced material is combined with the above-mentioned epoxy resin film, and after extrusion impregnation and degassing, the extrusion pressure is 0.1-0.2MPa, so that the UV-curable epoxy resin composition fully impregnates the fiber-reinforced material, and then the film is wound up and packaged in the dark. e. Curing treatment of the rolled-up UV-cured epoxy prepreg can be completed by curing at 30~55℃ for 10~40 hours.

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