Interface toughened high-performance prepreg yarn for dry winding, preparation method and application thereof

Abstract

The application discloses an interface toughening high-performance prepreg yarn for dry winding and a preparation method and application thereof, and relates to the technical field of composite materials for winding processes. The preparation method comprises the following steps: modifying carbon fibers by infiltrating interface modifiers, then removing the excess interface modifiers on the surface, drying and spreading the yarn to obtain interface modified carbon fibers; dipping the interface modified carbon fibers in a modified resin system to control the resin content of the tows to be 29-31%, and obtaining a prepreg yarn precursor; heating the prepreg yarn precursor to make the resin "contract", then shaping and winding to obtain the prepreg yarn. Through the improvement of the components of the interface modifier and the modified resin system, the integration of the carbon fiber prepreg yarn manufacturing can be realized, the subsequent fiber strength conversion rate is improved, the lossless separation in the process of winding and unwinding is realized, and the sticking problem in the winding process after the film is removed is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials for winding processes, in particular to an interface-toughened high-performance prepreg yarn for dry winding, a preparation method and application thereof. BACKGROUND

[0002] At present, new energy vehicles are developing rapidly at home and abroad. There are mainly two routes for new energy vehicles, one is the power battery module form mainly using ternary lithium batteries and lithium iron phosphate, and the other is the fuel cell form mainly using hydrogen fuel cells. The technical bottleneck that restricts the development of new energy vehicles is the range anxiety. At present, one of the mainstream forms is to reduce weight to effectively increase the range. The fiber continuous reinforced composite material has a relatively high specific stiffness and specific strength compared with traditional steel and alloy, and can obviously achieve the effect of weight reduction. The domestic development of the power battery module form mainly using ternary lithium batteries and lithium iron phosphate is relatively rapid and advanced, and has formed the application of most composite materials replacing traditional steel and alloy. For the new energy vehicle mainly using hydrogen fuel cells, the domestic development is relatively backward compared with foreign countries. In order to solve the problem of range, foreign countries have begun to use continuous fiber dry winding plastic inner container (type IV bottle) with greater hydrogen storage mass density instead of traditional continuous fiber wet winding aluminum alloy inner container (type III bottle). At present, there is no mature technology in China. The main difficulty is that there is no material (prepreg yarn) for dry winding in the industry, or there is related material, but due to the problem of industrial chain, the carbon fiber is re-extruded from the finished product, the conventional prepreg is manufactured through film coating and impregnation, and then the yarn bundle with a predetermined width is cut by a yarn cutting machine, and then PE film (protecting the prepreg yarn to prevent sticking) is coated to form the prepreg yarn. The prepreg yarn manufactured by the method has poor impregnation, and the carbon fiber yarn is damaged again after being re-extruded, which increases the amount of loose and broken yarns. The result is not only high manufacturing cost, but also poor 0° tensile performance conversion rate of the fiber, which cannot be used as type IV bottle material with high hydrogen storage mass density.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The purpose of the present application is to provide an interface-toughened high-performance prepreg yarn for dry winding, a preparation method and application thereof. The present application aims at the industry pain points, improves the performance conversion rate of the fiber winding composite material plate and NOL ring by modifying and matching the fiber and resin, and conducts integrated research on subsequent prepreg yarn production and manufacturing, so as to provide an interface-toughened prepreg yarn with low cost and high performance for dry winding in the industry.

[0005] The present application is realized as follows:

[0006] In a first aspect, the present application provides a method for preparing an interfacially toughened high-performance prepreg yarn for dry winding, comprising:

[0007] (1) preparing interfacially modified carbon fibers: the fibers are modified by impregnation with an interfacial modifier, then the excess interfacial modifier on the surface is removed, and the fibers are dried to obtain interfacially modified carbon fibers; the components of the interfacial modifier include, by mass percentage, 40-50% of a capped hydroxyl polyether, 1-3% of a polyether polyamine for flexible branched chain modification, 5-10% of a silicone modifier for modifying the surface activity of carbon fibers, and 40-55% of an epoxy diluent as a viscosity regulator, and the viscosity of the interfacial modifier is controlled to be below 300 cps;

[0008] (2) preparing a prepreg yarn precursor: the interfacially modified carbon fibers are impregnated with a modified resin system and the resin content of the tow is controlled to be 29-31% to obtain a prepreg yarn precursor; the components of the modified resin system include, by mass percentage, 59-64% of a modified epoxy resin, 24-27% of a modified toughening material, 5-7% of a functional filler, and 6-8% of a curing agent;

[0009] (3) preparing a prepreg yarn: the prepreg yarn precursor is heated to cause the surface resin portion of the prepreg yarn to shrink into the functional filler, then the tow is shaped by cold wind, and then the prepreg yarn is obtained by winding.

[0010] In an optional embodiment, the drying includes drawing the fibers from which the excess interfacial modifier has been removed into an infrared heating oven with guide rollers for drying to allow the interfacial modifier to react with the carbon fibers, the infrared heating oven has a length of 4-5 m and a temperature of 160-180°C.

[0011] In an optional embodiment, the spreading includes tension spreading the dried fibers through a width-spreading roller to a width of 5-6 mm.

[0012] In an optional embodiment, the interfacially modified carbon fibers are impregnated and the resin content is controlled by a double-roller gap method, which includes: the interfacially modified carbon fibers are drawn into the gap between a first roller and a second roller arranged oppositely, the modified resin system enters from above the first roller and the second roller, the first roller is provided with equidistant sawteeth, the second roller is provided with saw slots corresponding to the positions of the sawteeth, and when the sawteeth and the saw slots are engaged, the gap between the second roller and the first roller is 0.06-0.14 mm;

[0013] Preferably, the root width of the sawtooth on the first roller is 5-7 mm, the height of the sawtooth is 5.98-6.02 mm, every two sawtooths are taken as a sawtooth unit, the distance between the sawtooths in any one sawtooth unit is 4.95-5.05 mm, the distance between any two adjacent sawtooth units is 18-22 mm, and the depth of the saw groove on the second roller is 5.88-5.92 mm.

[0014] In an optional embodiment, the pre-preg is heated by hot air with a temperature of 70-90°C, and then the tows are shaped by cold air with a temperature of 5-12°C, and the roller areas of the heating device and the shaping device that are in contact with the pre-preg are treated by polytetrafluoroethylene coating to prevent resin adhesion and resin loss during the movement.

[0015] In an optional embodiment, the modified resin system has at least one of the following characteristics (1)-(4):

[0016] Characteristic (1): the modified epoxy resin comprises one or more of low-viscosity bisphenol A / F glycidyl ether resin, phenolic glycidyl ether epoxy resin, low-viscosity alicyclic glycidyl ester, and alicyclic glycidyl amine;

[0017] Characteristic (2): the modified toughening material comprises one or more of liquid modified toughening resin, core-shell rubber toughening particles, and thermoplastic toughening particles; the liquid modified toughening resin is a resin that can participate in the main reaction of the epoxy resin, the viscosity of the liquid modified toughening resin is controlled to be below 90000 cps at 25°C, the liquid modified toughening resin comprises one or more of PU-modified epoxy resin, TPU-modified epoxy resin, dimer acid-modified epoxy resin, and CTBN-grafted modified epoxy resin; the core-shell rubber toughening particles are core-shell toughening particles of acrylic polymer-coated rubber; the particle size distribution of the core-shell rubber toughening particles is 1-100 nanometers; the thermoplastic toughening particles comprise one or more of polyether sulfone, polyether ether ketone, and polyether ketone; the particle size of the thermoplastic toughening particles is 1-30 microns;

[0018] Characteristic (3): the functional filler is a multi-cavity micro-nano powder with a particle size of 1-5 microns; the multi-cavity micro-nano powder comprises at least one of mesoporous carbon sphere material and mesoporous silica material;

[0019] Characteristics (4): the curing agent is a powder curing agent or a liquid curing agent, the powder curing agent includes one or more of dicyandiamide, modified dicyandiamide, and organic urea curing agent, the liquid curing agent includes a boron trifluoride amine complex, preferably, the boron trifluoride amine complex includes one or more of Anchor 1053, Anchor 1040, Anchor 1115, BF3-400, and BF3-piperidine.

[0020] In an optional embodiment, in the components of the modified resin system, the modified epoxy resin includes bisphenol A / F epoxy glycidyl ether 31-34%, bisphenol A epoxy glycidyl ether 15%, and alicyclic glycidyl ester 10-18%, the modified toughening material includes liquid toughening agent 9-12%, core-shell rubber particles 7-9%, and thermoplastic toughening particles 6-8%;

[0021] The preparation method of the modified resin system includes:

[0022] 1) high-temperature dissolution of the bisphenol A / F epoxy glycidyl ether and the thermoplastic toughening particles at 120-130℃, and formation of a concentrated solution after cooling;

[0023] 2) adding the concentrated solution to a mixture of the alicyclic glycidyl ester, the liquid toughening agent, and the bisphenol A epoxy glycidyl ether, and blending at 65-75℃;

[0024] 3) adding the core-shell rubber particles to 2) for blending, and uniformly mixing for standby;

[0025] 4) adding the functional filler to 3) for blending modification;

[0026] 5) adding the curing agent to 4).

[0027] In a second aspect, the application provides a dry-winding interfacial toughening high-performance prepreg, which is prepared by the preparation method of the dry-winding interfacial toughening high-performance prepreg according to any one of the preceding embodiments.

[0028] In a third aspect, the application provides an application of the dry-winding interfacial toughening high-performance prepreg according to the preceding embodiments in the preparation of a dry-winding hydrogen storage cylinder.

[0029] In a fourth aspect, the application provides a new energy vehicle, which includes a dry-winding hydrogen storage cylinder prepared from the dry-winding interfacial toughening high-performance prepreg according to the preceding embodiments.

[0030] The application has the following beneficial effects:

[0031] The preparation method of the interface-toughened high-performance prepreg yarn for dry winding provided by the application can realize the integration of carbon fiber manufacturing and prepreg yarn manufacturing, changes the traditional production step-by-step manufacturing method, is conducive to reducing the secondary wear of carbon fiber in the manufacturing of the prepreg yarn, and increases the performance play rate of the fiber rear-end product. Meanwhile, through the integrated manufacturing, the cost and energy consumption are also effectively reduced. The surface interface of the carbon fiber is modified by using the interface modifier, and the tough interface layer is used as the transfer layer, so that the micro-cracks can be effectively resisted, the fiber strength conversion rate is improved, and the fiber performance conversion rate is increased by 30-40% compared with the wet winding. In addition, the modified resin system is optimized and modified, the lossless separation in the process of winding and unwinding is realized, and the sticking problem in the winding of the non-film is solved. The resin content can be accurately controlled, the resin content is controlled within ±2%, the fiber content stability of the rear-end product is effectively improved, the mechanical property stability of the whole product is improved, and the flatness is also greatly improved compared with the traditional wet winding. The interface-toughened high-performance prepreg yarn for dry winding prepared by using the preparation method of the interface-toughened high-performance prepreg yarn for dry winding provided by the application has the advantages of not sticky yarn and not sticky hand, stable fiber content, and stable mechanical property, the fiber performance conversion rate is improved without damaging the fiber, the cost is effectively reduced, and thus the problems of high price and poor performance of the material for dry winding are solved. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0033] Figure 1 The structure schematic diagram of the first roller and the second roller in the double-roller gap method provided by the application is shown in the figure.

[0034] Figure 2 The schematic diagram of the pre-stage conventional treatment process of the carbon fiber is shown in the figure.

[0035] Figure 3 The process schematic diagram of the preparation method of the interface-toughened high-performance prepreg yarn for dry winding provided by the application realizing the integrated manufacturing of the carbon fiber and the prepreg yarn is shown in the figure.

[0036] Figure 4 The schematic diagram of the traditional carbon fiber manufacturing is shown in the figure.

[0037] Figure 5 The process schematic diagram of the preparation of the prepreg yarn by using the split type after the traditional carbon fiber manufacturing is shown in the figure.

[0038] Icons: 110 - First roller; 111 - Saw teeth; 120 - Second roller; 121 - Saw groove. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0040] This invention provides a method for preparing interface-toughened high-performance prepreg yarn for dry winding, comprising the following steps:

[0041] (1) Preparation of interface-modified carbon fibers.

[0042] The fiber is modified by impregnating it with an interface modifier, then removing the excess interface modifier from the surface, drying it, and then spreading it into yarn to obtain interface-modified carbon fiber.

[0043] The fiber provided in this application is wet-spun carbon fiber from a production line without sizing agent coating. It has undergone a series of conventional treatments (as shown in Figure 2), including but not limited to: oiling, pre-oxidation, low-temperature carbonization, high-temperature carbonization, anodizing surface treatment, water washing and drying.

[0044] Traditional processes involve directly applying a water-based sizing agent to the carbon fibers that have undergone the above treatment (e.g., ...). Figure 4 As shown), however, in this application, the carbon fiber is impregnated with an interface modifier (such as...). Figure 3 As shown in the figure, the interface modifier provided in this application differs from traditional carbon fiber sizing agents. Traditional sizing agents are made by emulsifying various substances such as epoxy resin (20-25%), emulsifier (5-10%), lubricant (2-5%), and water. In this application, the interface modifier, by mass percentage, includes 40-50% end-hydroxyl polyether, 1-3% polyether polyamine for flexible branching modification, 5-10% organosilicon modifier for modifying the surface activity of carbon fibers, and 40-55% epoxy diluent as a viscosity modifier. The viscosity of the interface modifier is controlled below 300 cps. The active groups of the polyether polyamine can react with both the hydroxyl groups on the carbon fibers and the end-hydroxyl polyether, and can also subsequently react with the epoxy resin to form a bridging effect. The organosilicon modifier has good toughness and mainly improves the polarity of the interface, which is beneficial for ensuring interface wetting and allowing for better subsequent resin wetting.

[0045] The capped hydroxyl polyether includes but is not limited to one or more of T13, T14, T16, the polyether polyamine includes but is not limited to one or more of D230, T403, D220 and D1000, the silicone modifier includes but is not limited to one or more of USI2301, USI2302 and USI2312, and the epoxy diluent includes but is not limited to one or more of 1,4-butanediol diglycidyl ether, Epodil 746, XY216 and XY669. In the present application, the surface of the carbon fiber after conventional treatment is formed with various groups such as hydroxyl, carboxyl and the like, and the capped hydroxyl polyether and the polyether polyamine in the interface modifier can react with the groups on the carbon fiber, so that the interface modifier is bonded to the carbon fiber, and the silicone modifier can form hydrogen bonds with the hydroxyl and carboxyl groups on the carbon fiber, so that the flexible chain is grafted on the surface of the carbon fiber, the interface toughness of the fiber is improved, and the silicone modifier can also maintain the wettability of the interface, so that the subsequent resin can be better wetted.

[0046] The interface modifier provided by the present application is different from the traditional sizing agent in that the interface modifier and the traditional sizing agent play different roles on the carbon fiber. The main role of the interface modifier is to form a flexible interface layer between the resin layer and the fiber layer through chemical reaction and hydrogen bonding. The main role of the sizing agent is to use epoxy resin as a fiber bundling agent and an affinity agent for subsequent epoxy resin, and the internal lubricant plays a role in protecting the fiber from friction with the roller.

[0047] The drying includes drawing the fiber from which the excess interface modifier is removed into an infrared heating oven with guide rollers to dry the interface modifier and bond it to the carbon fiber. The length of the infrared heating oven is 4-5 m, and the temperature is 160-180℃. The spreading includes tension spreading the dried fiber through a width setting spreader roller, and the spreading is 5-6 mm.

[0048] (2) Preparing a prepreg precursor.

[0049] The interface modified carbon fiber is impregnated with the modified resin system, and the resin content of the fiber bundle is controlled to be 29-31%, to obtain a prepreg precursor.

[0050] The key point in preparing the prepreg precursor is the ratio of the modified resin system and the control of the resin content on the surface of the interface modified carbon fiber.

[0051] First, as for the ratio of the modified resin system, the components of the modified resin system in the present application include, by mass percentage, 59-64% of modified epoxy resin, 24-27% of modified toughening material, 5-7% of functional filler and 6-8% of curing agent.

[0052] Specifically, the modified epoxy resin includes one or more of a low viscosity bisphenol A / F glycidyl ether resin, a phenolic glycidyl ether epoxy resin, a low viscosity alicyclic glycidyl ester, and an alicyclic glycidyl amine.

[0053] The modified toughening material includes one or more of a liquid modified toughening resin, a core-shell rubber toughening particle, and a thermoplastic toughening particle; the liquid modified toughening resin is a resin that can participate in the main reaction of the epoxy resin, the viscosity of the liquid modified toughening resin is controlled to be less than 90000 cps at 25°C, and the liquid modified toughening resin includes one or more of a PU-modified epoxy resin, a TPU-modified epoxy resin, a dimer acid-modified epoxy resin, and a CTBN-grafted modified epoxy resin; the core-shell rubber toughening particle is a core-shell toughening particle of an acrylic polymer-coated rubber; the particle size distribution of the core-shell rubber toughening particle is 1-100 nanometers; and the thermoplastic toughening particle includes one or more of a polyether sulfone, a polyether ether ketone, and a polyether ketone; the particle size of the thermoplastic toughening particle is 1-30 microns. In the present application, the polyether component of the thermoplastic toughening particle and the polyether component (end-capped hydroxyl polyether, polyether polyamine) in the interfacial modifier can achieve similar compatibility, so that the connection effect of the modified resin system and the interface is better, and the modified resin system is also more conducive to infiltrating the carbon fibers.

[0054] The functional filler is a multi-cavity micro-nano powder with a particle size of 1-5 microns; the multi-cavity micro-nano powder includes at least one of a mesoporous carbon sphere material and a mesoporous silica material.

[0055] The curing agent is a powder curing agent or a liquid curing agent; the powder curing agent includes one or more of dicyandiamide, modified dicyandiamide, and an organic urea curing agent; the liquid curing agent includes a boron trifluoride amine complex; preferably, the boron trifluoride amine complex includes one or more of Anchor 1053, Anchor 1040, Anchor 1115, BF3-400, and BF3-piperidine.

[0056] In addition, in order to more clearly illustrate the preparation process of the modified resin system of the present application, the present application takes the components of the modified resin system as an example, in which the modified epoxy resin includes bisphenol A / F epoxy glycidyl ether 31-34%, bisphenol A epoxy glycidyl ether 15%, and alicyclic glycidyl ester 10-18%, and the modified toughening material includes liquid toughening agent 9-12%, core-shell rubber particles 7-9%, and thermoplastic toughening particles 6-8%, and lists the preparation method of the modified resin system, which includes:

[0057] 1) Dissolve the bisphenol A / F epoxy glycidyl ether and the thermoplastic toughening particle at 120-130°C to form a concentrated solution after cooling;

[0058] 2) adding the concentrated liquid into the mixture of alicyclic glycidyl ester, liquid toughening agent and bisphenol A epoxy glycidyl ether, and blending at 65-75℃;

[0059] 3) adding core-shell rubber particles into 2) and blending uniformly for use;

[0060] 4) adding functional fillers into 3) and blending modification;

[0061] 5) adding curing agent into 4).

[0062] The modified resin system provided in the application has good wettability, and the resin can realize rapid "internal contraction" at 70-90℃ to complete the apparent non-stick effect, so that the prepreg yarn can be unwound without damage in the subsequent winding process.

[0063] Secondly, for the control of the resin content on the surface of the interface-modified carbon fiber, the double-roller gap method is used in the application to impregnate the interface-modified carbon fiber and control the resin content.

[0064] The double-roller gap method comprises: the interface-modified carbon fiber is drawn into the relative first roller 110 and second roller 120, and the modified resin system enters from above the first roller 110 and second roller 120. Figure 1 The first roller 110 is provided with equidistant sawteeth 111, and the second roller 120 is provided with saw grooves 121 corresponding to the positions of the sawteeth 111. When the sawteeth 111 and the saw grooves 121 are engaged, the gap between the first roller 110 and the second roller 120 is 0.06-0.14mm. Preferably, the root width of the sawteeth 111 on the first roller 110 is 5-7mm, the height of the sawteeth 111 is 5.98-6.02mm, the distance between the sawteeth 111 is 4.95-5.05mm, every two sawteeth 111 is a sawtooth unit, the distance between the sawteeth in any one of the sawtooth units is 4.95-5.05mm, the distance between any two adjacent sawtooth units is 18-22mm, and the depth of the saw grooves 121 on the second roller 120 is 5.88-5.92mm.

[0065] Since the equidistant sawteeth are adopted in the present application to realize the distance fixing of the surfaces of the first roller 110 and the second roller 120, specifically, by controlling the distance between the sawteeth in each sawteeth unit and the gap between the second roller 120 and the first roller 110, the volume of the sawteeth unit is fixed, and the gap between the first roller 110 and the second roller 120 is kept constant, so that the amount of the modified resin system entering between the first roller 110 and the second roller 120 is also constant, and the content of the resin can be well controlled. In actual situations, the distance between the first roller 110 and the second roller 120 or the distance between the sawteeth 111 can be changed according to the process requirements to realize the control of different resin contents. In order to ensure the resin content, the roller area in contact with the prepreg is treated with a polytetrafluoroethylene coating to ensure that the resin does not stick together and does not cause resin loss during the running.

[0066] (3) Preparing the prepreg.

[0067] The prepreg precursor is heated to make the resin shrink into the functional filler, then the tows are shaped by cold air, and then the prepreg is obtained by winding.

[0068] In order to ensure the impregnation of the prepreg, the present application adopts the way of hot air baking to perform secondary impregnation in the running. The prepreg precursor is heated by hot air with a temperature of 70-90℃, at this time the resin shrinks into the functional filler, the apparent non-stick effect is completed, so as to realize the non-damage unwinding of the prepreg. Then the tows are shaped by cold air with a temperature of 5-12℃, to ensure that there is no sticking between the prepreg tows during subsequent winding.

[0069] The interface toughening high-performance prepreg for dry winding obtained by the above method has a non-sticky surface and does not stick to the yarn, and the material can better realize micro stress conduction under stress after the prepreg is solidified, thereby effectively improving the tensile properties of the NOL ring and greatly improving the strength of the dry winding hydrogen storage cylinder prepared by the prepreg. It can be widely used in the preparation of dry winding hydrogen storage cylinders, and the dry winding hydrogen storage cylinder prepared can also be used to prepare new energy vehicles.

[0070] The features and properties of the present application are further described in detail below in conjunction with the examples.

[0071] Example 1

[0072] The present embodiment is an interface toughening high-performance prepreg SS-1 for dry winding, which is prepared by Figure 2 and Figure 3 It should be understood that Figure 2 and Figure 3 indicate a whole process, and for clearer description, the different places are listed separately as Figure 3 .

[0073] The preparation method comprises the following steps:

[0074] (1) The carbon fiber is selected from the wet-spun wet-drawn carbon fiber HF30F (T700 grade carbon fiber) on the production line of Jiangsu Hengshen Company without coating sizing agent. After the last carbonization is completed, the carbon fiber is guided into a surface modification tank, and an interfacial modifier is placed in the tank. The interfacial modifier is a mixture of 45% T13 (Jiahua Chemical), 3% D230 (BASF Company), 7% USI2301 (Lian Silicon Chemical), and 45% 1,4-butanediol diglycidyl ether (Wanhua Chemical). The total viscosity of the interfacial modifier is 230 cps at 25 DEG C. After the carbonized fiber is impregnated with the interfacial modifier, it is first extruded by an extrusion roller to squeeze out the excess interfacial modifier on the surface, and then enters an infrared heating oven (oven length 4-5 m) with a guide roller. The oven temperature is set at 170 DEG C, so that the interfacial modifier and the carbon fiber are bonded. The excess 1,4-butanediol diglycidyl ether will gradually volatilize during baking. The surface-modified carbon fiber is tensioned and spread by a width-setting spreader roller, and is spread into 5.1 mm.

[0075] (2) Then, while the fiber is still hot, it enters a resin impregnation roller, and the resin content on the fiber is controlled at 30±1% by a special double-roller gap method. The resin system comprises bisphenol F epoxy glycidyl ether (NPEF170, 34 parts), bisphenol A epoxy glycidyl ether (NPES901, 15 parts), alicyclic glycidyl ester (S-21, 10 parts), a liquid toughener (EPU-133, 12 parts), core-shell rubber particles (MX125, 7 parts), thermoplastic toughening particles (PES, 8 parts), functional fillers (mesoporous carbon spheres, 6 parts), and a liquid curing agent (Anchor 1040, 8 parts).

[0076] The mixing modification process of the resin is as follows: 1) high-temperature dissolution of bisphenol F epoxy glycidyl ether and PES at 120-130°C, and formation of concentrated liquid T1 after cooling; 2) adding concentrated liquid T1 into a mixed liquid of alicyclic glycidyl ester S-21, liquid toughening agent EPU-133 and bisphenol A epoxy glycidyl ether NPES901, and blending at 70°C; 3) adding core-shell rubber MX125 into 2) and uniformly mixing for standby; 4) adding functional filler mesoporous carbon spheres into 3) for blending modification; 5) adding liquid curing agent Anchor1040 into 4), and finally forming resin system S-1, with the resin 50°C viscosity controlled at 12000cps. The formed resin S-1 is stably controlled at 50±3°C through a specific heat preservation device, and is introduced into the upper part of the corresponding first roller 110 and second roller 120 through a heat preservation pipe, and flows into the gap between the first roller 110 and the second roller 120 at a constant flow rate (controlled by a valve). The gap between the first roller 110 and the second roller 120 when they are engaged is 0.1mm. The root width of the sawtooth 111 on the first roller 110 is 6mm, the height of the sawtooth 111 is 6mm, every two sawteeth form a sawtooth unit, the distance between the sawteeth in any sawtooth unit is 5mm, and the distance between any two adjacent sawtooth units is 20mm. The depth of the saw groove on the second roller is 5.9mm.

[0077] The temperature of the first roller 110 and the second roller 120 is maintained at 50±3°C by water circulation. By controlling the distance between the first roller 110 and the second roller 120, the pre-impregnated yarn precursor with a certain resin content is obtained by actual measurement.

[0078] (3) Through subsequent air blowing heating equipment (set at 75°C), the functional filler with multi-cavity structure, and the cohesive force of the entire resin system at 75-90°C, the resin is quickly "contracted" into the functional powder, reducing the content of resin exposed outside the fiber. Then the yarn is "shaped" by a cold air equipment. At this time, the yarn appears not sticky. Finally, the yarn is wound on a winding machine through a winding equipment. After the above steps, the SS-1 pre-impregnated yarn is formed.

[0079] (4) The prepared SS-1 pre-impregnated yarn is prepared into a NOL ring through a dry winding equipment. The prepared NOL ring is denoted as N-1.

[0080] Example 2

[0081] The present embodiment is a kind of dry winding interface toughening high performance pre-impregnated yarn SS-2, which is prepared by Figure 2 and Figure 3 The preparation method comprises the following steps:

[0082] (1) Carbon fiber is selected from Jiangsu Hengshen Company's production line of wet spray wet spinning carbon fiber HF30F (T700 grade carbon fiber) without sizing agent. After the last carbonization, the carbon fiber is guided into the surface modification tank, and the interfacial modifier is placed in the tank. The interfacial modifier is composed of 50% T14 (Jiahua Chemical), 2% T403 (Huntsman), 5% USI2301 (Lian Silicon Chemical), 43% Epodil 746 (Yingchuang Chemical), and the total viscosity is 160 cps at 25°C. After carbonization, the fiber is first extruded by the extrusion roller to squeeze out the excess interfacial modifier on the surface, and then enters the infrared heating oven with guide rollers (oven length 4~5m), the oven temperature is set at 170°C, so that the interfacial modifier and the carbon fiber are bonded. Excess Epodil746 will gradually volatilize during baking. The surface modified carbon fiber is tensioned by the width spreading roller to become 5.1mm.

[0083] (2) Then, while the fiber is still hot, it enters the resin impregnation roller, and the resin content on the fiber is controlled at 30±1% by a special double-roller gap method. The resin system consists of bisphenol A / F epoxy glycidyl ether (NPEF185, 31 parts), bisphenol A epoxy glycidyl ether (NPES901, 15 parts), alicyclic glycidyl ester (S-21, 18 parts), liquid toughening agent (HyPox DA323, 9 parts), core-shell rubber particles (MX257, 9 parts), thermoplastic toughening particles (PES, 6 parts), functional filler (mesoporous carbon spheres, 6 parts), powder curing agent (dicyandiamide 5 parts, UR500, 1 part).

[0084] The mixing modification process of the resin is as follows: 1) high-temperature dissolution of bisphenol A / F epoxy glycidyl ether and PES at 120-130℃, and formation of concentrated solution T2 after cooling; 2) adding concentrated solution T2 into a mixed solution of alicyclic glycidyl ester S-21, liquid toughening agent HyPox DA323 and bisphenol A epoxy glycidyl ether NPES901, and blending at 70℃; 3) adding core-shell rubber MX257 into 2) and uniformly mixing for standby; 4) adding functional filler mesoporous silica into 3) for blending modification; 5) adding powder curing agent dicyandiamide and UR500 into 4), and finally forming resin system S-2, with the resin 50℃ viscosity controlled at 15000cps. The formed resin S-2 is stably controlled at 50±3℃ through a specific heat preservation device, and is introduced into the upper part of the corresponding first roller 110 and second roller 120 (the first roller 110 and the second roller 120 are the same as those in Example 1) through a heat preservation pipe, and flows into the gap between the first roller 110 and the second roller 120 at a constant flow rate (controlled by a valve). The temperature of the first roller 110 and the second roller 120 is maintained at 50±3℃ by water circulation, and the distance between the first roller 110 and the second roller 120 is controlled, and through actual measurement, the resin content of the impregnated pre-spread yarn precursor is obtained.

[0085] (3) The yarn is subjected to rapid "constriction" through subsequent air blowing and heating equipment (set at 75℃), and then is subjected to "setting" through a cold air equipment, at this time, the yarn appears a non-sticky state, and finally is wound onto a winding machine through a winding equipment. Through the above steps, the SS-2 pre-spread yarn is formed.

[0086] (4) The prepared SS-2 pre-spread yarn is subjected to NOL ring preparation through dry winding equipment, and the prepared NOL ring is denoted as N-2.

[0087] Example 3

[0088] The present example provides a dry winding interface toughening high-performance pre-spread yarn, and the preparation method is basically the same as that in Example 1, and the only difference is that the components and amounts of the modified resin system in the present example are different from those in Example 1.

[0089] In the present example, the composition of the resin system is bisphenol A / F epoxy glycidyl ether (NPEF185, 62 parts), core-shell rubber particles (MX257, 25 parts), functional filler (mesoporous carbon spheres, 7 parts), powder curing agent (dicyandiamide 5 parts, UR500, 1 part).

[0090] The mixing modification process of the resin is as follows: 1) heat the bisphenol A / F epoxy glycidyl ether to 60°C; 2) add the core-shell rubber MX257 to 1) and blend uniformly for use; 3) add the functional filler mesoporous silica to 2) and blend; 4) add the powder curing agent dicyandiamide and UR500 to 3), and finally form the resin system S-3.

[0091] The prepared prepreg yarn is denoted as SS-3. The prepared SS-3 prepreg yarn is prepared into a NOL ring through a dry winding device, and the prepared NOL ring is denoted as N-3.

[0092] Comparative Example 1

[0093] This comparative example provides a method for preparing a prepreg yarn, which uses the finished carbon fiber HF30F of Jiangsu Hengshen Company (off-line, carbon fiber coated with sizing agent on the surface), and the prepreg yarn is prepared by the methods of Figure 2 , Figure 4 and Figure 5 , Figure 4 and Figure 5 The step-by-step preparation is realized, wherein the resin system is the same as S-1 in the embodiment, and the corresponding prepared prepreg yarn is SS-4.

[0094] The prepared SS-4 prepreg yarn is prepared into a NOL ring through a dry winding device, and the prepared NOL ring is denoted as N-4.

[0095] Comparative Example 2

[0096] This comparative example provides a method for preparing a prepreg yarn, which uses the finished carbon fiber HF30F of Jiangsu Hengshen Company (off-line, carbon fiber coated with sizing agent on the surface), and the prepreg yarn is prepared by the methods of Figure 2 , Figure 4 and Figure 5 , Figure 4 and Figure 5 The step-by-step preparation is realized, wherein the resin system is the same as S-2 in the embodiment, and the corresponding prepared prepreg yarn is SS-5.

[0097] The prepared SS-5 prepreg yarn is prepared into a NOL ring through a dry winding device, and the prepared NOL ring is denoted as N-5.

[0098] Comparative Example 3

[0099] This comparative example provides a dry winding interface toughening high-performance prepreg yarn, and the preparation method is basically the same as that of Example 1, except that the composition and amount of the interface modifier in this comparative example are different from those of Example 1.

[0100] In the present comparative example, the modified resin system is composed of 27% of T13 (Jiahuaxing Chemical), 10% of D230 (BASF), 3% of USI2301 (Lian Silicon Chemical), 60% of 1,4-butanediol diglycidyl ether (Wanhua Chemical).

[0101] The prepared prepreg yarn is denoted as SS-6. The prepared SS-6 prepreg yarn is prepared into NOL ring through dry winding equipment, and the prepared NOL ring is denoted as N-6.

[0102] Comparative Example 4

[0103] The present comparative example provides an interfacial toughening high-performance prepreg yarn for dry winding, and the preparation method thereof is basically the same as that of Example 1, and the only difference is that the composition and amount of the modified resin system in the present comparative example are different from those of Example 1, and specifically, the modified toughening material is omitted.

[0104] In the present comparative example, the resin system is composed of bisphenol F epoxy glycidyl ether (NPEF170, 42 parts), bisphenol A epoxy glycidyl ether (NPES901, 28 parts), alicyclic glycidyl ester (S-21, 16 parts), functional filler (mesoporous carbon sphere, 7 parts), and liquid curing agent (Anchor 1040, 7 parts).

[0105] The prepared prepreg yarn is denoted as SS-7. The prepared SS-7 prepreg yarn is prepared into NOL ring through dry winding equipment, and the prepared NOL ring is denoted as N-7.

[0106] Comparative Example 5

[0107] The present comparative example provides an interfacial toughening high-performance prepreg yarn for dry winding, and the preparation method thereof is basically the same as that of Example 1, and the only difference is that the composition and amount of the modified resin system in the present comparative example are different from those of Example 1, and specifically, the functional filler is omitted.

[0108] In the present comparative example, the resin system is composed of bisphenol F epoxy glycidyl ether (NPEF170, 36 parts), bisphenol A epoxy glycidyl ether (NPES901, 15 parts), alicyclic glycidyl ester (S-21, 12 parts), liquid toughening agent (EPU-133, 14 parts), core-shell rubber particles (MX125, 9 parts), thermoplastic toughening particles (PES, 6 parts), and liquid curing agent (Anchor 1040, 8 parts).

[0109] The prepared prepreg yarn is denoted as SS-8. The prepared SS-8 prepreg yarn is prepared into NOL ring through dry winding equipment, and the prepared NOL ring is denoted as N-8.

[0110] Comparative Example 6

[0111] The present comparative example provides a wet winding method commonly used in the winding field, which uses constant HF30F fiber + Huiba's AF4206 winding resin (a commonly used resin in the wet winding field), to directly prepare NOL rings. The NOL ring sample is recorded as N-9. At the same time, the AF4206 is used to soak the HF30F fiber to test the multifilament strength, which is recorded as SF-1.

[0112] Experimental example

[0113] In the related examples and comparative examples, SS-1 to SS-8 and SF-1 pre-impregnated yarns are investigated for the resin content of the tows, the multifilament strength, the multifilament strength of the tows placed at 25±2℃ for different times, the NOL ring tensile strength, the unidirectional plate performance, and the gas cylinder burst performance according to the needs of the application scenario.

[0114] Table 1. Resin content statistical table of different example tows

[0115]

[0116] Note: The resin content test method uses the acetone washing method. For example, a 10 cm long tow is taken at the 200m position of the tow to test the resin content, and the method is used at other positions.

[0117] Table 2. Test result statistical table of multifilament strength of different examples at 25±2℃ for different times

[0118]

[0119] Table 3. Performance test result statistical table of different examples

[0120]

[0121] By comparing Example 1, 2 and Comparative Example 1-2, since the integrated method is used to manufacture the winding pre-impregnated yarn, the traditional sizing agent is no longer needed to protect the fiber from abrasion, but the flexible chain is used to modify the fiber surface, and then the precise content impregnation with epoxy resin is directly carried out, and finally the pre-impregnated yarn formed is obviously better than the pre-impregnated yarn prepared by secondary take-up and pay-off in Comparative Example 1 and 2, which is mainly because the flexible chain end is cleverly bonded with the carbon fiber after anodic oxidation at high temperature in this application or hydrogen bonding (carbon fiber-COOH and -OH are bonded with hydroxyl polyester polyol and polyether amine, and hydrogen bonding is formed with silicone modifier, so that the carbon fiber surface is grafted with flexible chain, and the interface toughness of the fiber is improved), and the subsequent fiber can better help the resin to impregnate the fiber (the fiber temperature rises, and the Young's contact angle of the resin to the fiber becomes smaller) when entering the impregnation roller, and at the same time, due to the modification of the resin system by the functional filler, the resin on the surface of the pre-impregnated yarn can enter the multi-cavity powder more during the subsequent 75℃ air blowing impregnation process due to the capillary effect of the multi-cavity structure of the functional filler and the shrinkage of the resin at high temperature, so that the surface drying phenomenon is realized, and the pre-impregnated yarn is not sticky and not sticky. At the same time, through the modification of the flexible interface, the material stress can better realize micro-stress conduction after the pre-impregnated yarn is solidified, so as to effectively improve the tensile properties of the NOL ring, and the strength of the pre-impregnated yarn dry winding gas cylinder is greatly improved.

[0122] As can be seen from Comparative Example 3, the filament strength decreases significantly after 4 days, indicating that the stability of the pre-impregnated yarn is insufficient, mainly because the proportion of the interface modifier is not appropriate, which causes the excess active amine in the interface layer to accelerate the reaction near the interface, so that the resin in the resin zone and the interface over zone reacts at different speeds, and then causes weak points, thereby causing serious performance degradation. Reflecting on the workpiece, the corresponding performance also decreases significantly. Comparative Example 3 changes the amount of interface modifier, and the pre-impregnated yarn obtained finally is significantly worse than Example 1.

[0123] As can be seen from Comparative Examples 4-5, canceling the toughening agent or functional filler in the resin component has a great influence on the pre-impregnated yarn. Especially Comparative Example 5 which cancels the functional filler, although the filament strength changes little, but due to the lack of the adsorption of the functional filler to the resin on the surface of the pre-impregnated yarn, the overall process operability of the pre-impregnated yarn is poor, and lossless peeling is difficult to achieve, thereby causing more fluff and broken yarns in the winding process, which affects the final performance conversion of the plate and the workpiece, and causes obvious performance degradation. Comparative Examples 4-5 change the amount of modified resin system, and the pre-impregnated yarn obtained finally is significantly worse than Example 1.

[0124] It can be seen from Comparative Example 6 that the dry-winding pre-impregnated yarn prepared by the method of the application has better performance than the wet-winding yarn of the same fiber, in addition to the above-mentioned advantages, the wet-winding yarn cannot accurately control the resin content as the pre-impregnated yarn in the application, and the fiber volume content is controlled at a high level, thereby improving the performance of the subsequent product.

[0125] In summary, the preparation method of the interface-toughened high-performance pre-impregnated yarn for dry winding provided by the application can realize the integration of carbon fiber manufacturing and pre-impregnated yarn manufacturing, which changes the traditional production step-by-step manufacturing method, is beneficial to reduce the secondary wear of carbon fiber in pre-impregnated yarn manufacturing, and increases the performance of the subsequent product. At the same time, through integrated manufacturing, the cost and energy consumption are also effectively reduced. The application modifies the surface interface of carbon fiber by using an interfacial modifier, and uses a tough interface layer as a transfer layer, which can effectively resist micro-cracks and improve the conversion rate of fiber strength in the subsequent process. Compared with wet-winding fiber performance, the NOL conversion rate is increased by 30-40%. In addition, the application also optimizes the modified resin system to realize lossless separation during the winding process, and solves the problem of adhesion in the winding process after film-free. The application can also accurately control the resin content, and the resin content is controlled within ± 2%, which effectively improves the stability of the fiber content of the subsequent product and improves the mechanical property stability of the whole product. At the same time, compared with the traditional wet-winding method, the flatness is also greatly improved. The interface-toughened high-performance pre-impregnated yarn for dry winding prepared by the preparation method of the interface-toughened high-performance pre-impregnated yarn for dry winding provided by the application has the advantages of not sticky yarn and not sticky hand, stable fiber content, and stable mechanical properties. The application can improve the performance conversion rate of the fiber without damaging the fiber, and effectively reduce the cost, thereby solving the problem of high price and poor performance of the material for dry winding.

[0126] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A method for preparing a high-performance prepreg yarn with interface toughening for dry winding, characterized in that, It includes: (1) Preparation of interface-modified carbon fiber: Carbon fiber with hydroxyl and carboxyl groups on its surface is impregnated with an interface modifier for modification, then the excess interface modifier on the surface is removed, and after drying, the interface modifier and the carbon fiber undergo a bonding reaction. The resulting yarn is then unrolled to obtain interface-modified carbon fiber. The interface modifier comprises, by mass percentage, 40-50% end-capped hydroxyl polyether, 1-3% polyether polyamine for flexible branching modification, 5-10% organosilicon modifier for modifying the surface activity of carbon fiber, and 40-55% epoxy diluent for use as a viscosity modifier. The viscosity of the interface modifier is controlled below 300 cps at 25°C. (2) Preparation of prepreg precursor: The interface-modified carbon fiber is impregnated with a modified resin system and the resin content of the filament bundle is controlled to be 29-31% to obtain the prepreg precursor; the components of the modified resin system include, by mass percentage, 59-64% modified epoxy resin, 24-27% modified toughening material, 5-7% functional filler and 6-8% curing agent; the functional filler is a multi-cavity micro-nano powder with a particle size of 1-5 micrometers; the multi-cavity micro-nano powder includes at least one of mesoporous carbon sphere material and mesoporous silica material; (3) Prepreg yarn preparation: The prepreg yarn precursor is heated to shrink the resin portion on the surface of the prepreg yarn precursor into the functional filler. Then, the yarn bundle is shaped by cold air and then wound up to obtain the prepreg yarn.

2. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 1, characterized in that, The drying process involves drawing the fibers, after removing excess interface modifier, into an infrared heating oven equipped with guide rollers for drying. The infrared heating oven is 4-5m long and has a temperature of 160-180℃.

3. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 1, characterized in that, The yarn spreading process involves spreading the dried fibers under tension using a fixed-width spreading roller, resulting in a yarn thickness of 5-6 mm.

4. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 1, characterized in that, The interface-modified carbon fiber is impregnated and the resin content is controlled using a two-roller gap method. The two-roller gap method includes: the interface-modified carbon fiber is drawn into the space between a first roller and a second roller arranged opposite each other; the modified resin system enters from above the first roller and the second roller; the first roller is provided with equidistant serrations; the second roller is provided with serrations at the corresponding positions of the serrations; when engaged, the gap between the second roller and the first roller is 0.06-0.14 mm.

5. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 4, characterized in that, The root width of the saw teeth on the first roller is 5-7 mm, the height of the saw teeth is 5.98-6.02 mm, each pair of saw teeth constitutes a saw tooth unit, the distance between the saw teeth in any saw tooth unit is 4.95-5.05 mm, the spacing between any two adjacent saw tooth units is 18-22 mm, and the depth of the saw groove on the second roller is 5.88-5.92 mm.

6. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 1, characterized in that, The prepreg precursor is heated with hot air at a temperature of 70-90℃, and then the yarn bundle is shaped with cold air at a temperature of 5-12℃. At the same time, the roller areas of the heating equipment and the shaping equipment that come into contact with the prepreg precursor are treated with polytetrafluoroethylene coating to ensure that the resin does not stick and that no resin is lost during the process.

7. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 1, characterized in that, The modified resin system has at least one of the following characteristics (1)-(3): Feature (1): The modified epoxy resin includes one or more of the following: low viscosity bisphenol A / F epoxy glycidyl ether, phenolic glycidyl ether epoxy resin, low viscosity alicyclic glycidyl ester and alicyclic glycidyl amine. Feature (2): The modified toughening material includes one or more of liquid modified toughening resin, core-shell rubber toughening particles, and thermoplastic toughening particles; the viscosity of the liquid modified toughening resin is controlled below 90,000 cps at 25°C; the liquid modified toughening resin includes one or more of PU modified epoxy resin, TPU modified epoxy resin, dimer acid modified epoxy resin, and CTBN grafted modified epoxy resin; the core-shell rubber toughening particles are acrylic polymer-coated rubber core-shell toughening particles; the particle size of the core-shell rubber toughening particles is 1-100 nanometers; the thermoplastic toughening particles include one or more of polyethersulfone, polyetheretherketone, and polyetherketone; the particle size of the thermoplastic toughening particles is 1-30 micrometers. Feature (3): The curing agent is a powder curing agent or a liquid curing agent. The powder curing agent includes one or more of dicyandiamide, modified dicyandiamide, and organic urea curing agents. The liquid curing agent includes boron trifluoride amine complexes. The boron trifluoride amine complexes include one or more of Anchor1053, Anchor1040, Anchor1115, BF3-400, and BF3-piperidine.

8. The method for preparing interface-toughened high-performance prepreg yarn for dry winding according to claim 1, characterized in that, The modified resin system comprises the following components: the modified epoxy resin includes 31-34% bisphenol A / F glycidyl ether, 15% bisphenol A glycidyl ether, and 10-18% alicyclic glycidyl ester; the modified toughening material includes 9-12% liquid toughening agent, 7-9% core-shell rubber particles, and 6-8% thermoplastic toughening particles. The preparation method of the modified resin system includes: 1) The bisphenol A / F epoxy glycidyl ether and the thermoplastic toughening particles are dissolved at a high temperature of 120~130℃, and then cooled to form a concentrated solution; 2) Add the concentrated solution to the mixture of the alicyclic glycidyl ester, the liquid toughening agent and the bisphenol A glycidyl ether, and blend at 65-75°C; 3) Add the core-shell rubber particles to 2) and mix thoroughly for later use; 4) Add the functional filler described in 3) to perform blending modification; 5) Add the curing agent to 4).

9. A high-performance prepreg yarn with interface toughening for dry winding, characterized in that, It is prepared using the method for preparing interface-toughened high-performance prepreg yarn for dry winding as described in any one of claims 1-8.

10. The application of the interface-toughened high-performance prepreg yarn for dry winding as described in claim 9 in the preparation of dry-wound hydrogen storage cylinders.

11. A new energy vehicle, characterized in that, It includes dry-wound hydrogen storage cylinders prepared using interface-toughened high-performance prepreg yarn for dry winding as described in claim 9.

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