Method for preparing integrated control arm by taking continuous fiber reinforced reactive nylon as framework piece

Abstract

The invention belongs to the technical field of materials, and discloses a method for preparing an integrated control arm by taking continuous fiber reinforced reactive nylon as a framework piece, which comprises the following steps: paving continuous fibers in a framework piece mold, and injecting resin consisting of a low-viscosity polymeric monomer material to form the framework piece consisting of the continuous fiber reinforced reactive nylon; the metal insert is placed in a mold, the resin is kept in a semi-molten state, the short fiber reinforced homologous resin is subjected to injection molding, a connecting piece of the covered edge and the reinforcing rib is formed, and the connecting piece and the framework piece are fused to form the integrated control arm product. The integrated control arm of a three-dimensional structure is formed, sheet punching, hanging and positioning are not needed, mechanical properties are influenced, and a series of control arms with the characteristics of product diversification, high strength, low cost and the like can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as a framework member. Background Art

[0002] Thermoplastic composites have subversive advantages over aluminum-magnesium alloys and thermosetting composites. Continuous fiber reinforced thermoplastic composites have better NVH performance, greater fatigue damage tolerance, and lower carbon emissions compared to aluminum-magnesium alloys; they have a more environmentally friendly processing technology, stronger impact resistance, recyclability, and higher production efficiency compared to thermosetting composites; at the same time, they have the best weight reduction effect and the lowest cost. The multi-material hybrid application with continuous fiber reinforced thermoplastic composites as the main load-bearing framework and high-glass fiber engineering plastics playing a role in connection, cooperation, and reinforcement has the broadest application prospects and can be applied to brake pedals, control arms, seats, etc.

[0003] The high strength of continuous fiber reinforced thermoplastic composites mainly comes from continuous fibers. Currently, with continuous fiber reinforced thermoplastic composites as the main load-bearing framework, it is basically formed by hot pressing continuous fiber reinforced sheets. During the hot pressing process, the fibers will slip, and wrinkles will occur at the corners. Therefore, for some complex workpieces, notches need to be cut on the sheets, resulting in discontinuous fibers and a significant decrease in mechanical strength. Moreover, this part is the most stress-concentrated area of the product, leading to the product not meeting the mechanical requirements or a decrease in service life. Therefore, the hot pressing forming process can only be used to manufacture simple structural parts.

[0004] In addition, the sheets of continuous fiber reinforced thermoplastic composites are currently hydrolyzed and ring-opened to polymerize into nylon resin, and then the resin is cast into a film or cryogenically pulverized and hot pressed with continuous fibers to form composites. During the hot pressing process, the molten viscosity of the resin is higher than that of small molecule monomers, and it is more difficult to impregnate with glass fibers, which results in a lower combination of the resin and glass fibers. The preparation process flow is long, the cost is high, and it cannot be customized and developed, resulting in low utilization rate.

[0005] There have been relevant literature reports on continuous fiber reinforced polyamide anionic polymerization. However, in the reports, mainly sheets are manufactured, and the sheet area is small, and three-dimensional structure products cannot be formed. The main method is to first mix AB materials and then inject or vacuum suck them into the mold. However, after the AB materials are mixed, the materials start to react, resulting in a short impregnation time, and it is impossible to manufacture large-area sheets and complex three-dimensional structure products. Moreover, because shrinkage occurs during the polymerization reaction and monomers cannot be replenished in time, shrinkage warping occurs and the surface is not smooth enough. Summary of the Invention The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and provide a method for preparing an integrated control arm with continuous fiber-reinforced reactive nylon as the skeleton member, particularly a preparation method of continuous fiber-reinforced reactive nylon as the skeleton member, and fusing with a homologous reinforcing resin to obtain a series of control arms with product diversification, high strength, low cost and other characteristics.

[0006] To solve the above technical problem, the technical solution proposed by the present invention is as follows: A method for preparing an integrated control arm with continuous fiber-reinforced reactive nylon as the skeleton member, comprising the following steps: (1) Lay continuous fibers flat in the skeleton member mold, raise the temperature to the polymerization temperature, then inject a resin composed of low-viscosity polymerization monomers, initiate anionic polymerization after completely impregnating the fibers, and form a skeleton member composed of continuous fiber-reinforced reactive nylon; (2) First place the metal inserts in the injection mold, transfer the skeleton member prepared in step (1) to the injection mold after infrared heating, and keep the resin in the skeleton member in a semi-molten state. At the same time, inject a short fiber-reinforced homologous resin composite material, so that while wrapping the metal inserts, form a hemming and reinforcing ribs on the skeleton member, and fuse and mold into an integrated control arm product.

[0007] In the above method, preferably, in the skeleton member obtained in step (1), the weight ratio of the continuous fibers is 40-70%, preferably 50-70%; the continuous fibers are at least one of glass fiber, carbon fiber, and basalt fiber formed into a fiber fabric, preferably glass fiber; the continuous fibers are laid in 5-7 layers in the mold, and 1-2 more layers are laid at the stress concentration points during the service process of the product.

[0008] Preferably, in step (1), the low-viscosity polymerization monomer is lactam, including caprolactam, enantholactam, laurolactam, preferably a copolymer of one or two of caprolactam and laurolactam; the low-viscosity polymerization monomer is heated to 140°C ± 10°C before being added to the skeleton member mold, and the moisture is removed by vacuum pumping.

[0009] Preferably, in step (1), the specific operation of injecting the resin composed of low-viscosity polymerization monomers includes the following steps: Add a part of the low-viscosity polymerization monomer to the A reaction kettle, and the remaining part of the low-viscosity polymerization monomer to the B reaction kettle. Heat the low-viscosity polymerization monomers in the A and B reaction kettles to 140°C ± 10°C, remove the moisture by vacuum pumping, then add an alkali catalyst to the A reaction kettle and a co-catalyst to the B reaction kettle, and vacuum pump again to obtain A material and B material; Then inject A material and B material into the skeleton member mold simultaneously under high pressure, and the weight ratio of A material and B material in the skeleton member mold is controlled at 0.9-1.1∶1.

[0010] Preferably, the weight ratio of the low-viscosity polymerization monomer to the alkali catalyst added in the A reactor is 1000:3-5. The alkali catalyst is at least one of sodium hydroxide, potassium hydroxide, and sodium ethoxide, preferably sodium hydroxide. The weight ratio of the low-viscosity polymerization monomer to the co-catalyst added in the B reactor is 93-98:2-3. The co-catalyst is at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), and lysine diisocyanate, preferably diphenylmethane diisocyanate. A toughening agent is also added to the B reactor, and the weight ratio of the toughening agent in the B material is 1-30%. The toughening agent is at least one of hydroxyl-terminated polytetrahydrofuran ether, hydroxyl-terminated polyvinyl alcohol, and hydroxyl-terminated polypropylene alcohol, preferably hydroxyl-terminated polytetrahydrofuran ether.

[0011] Preferably, in step (1), the injection pressure of the low-viscosity polymerization monomer is 10-16 MPa, the injection time of the pressure is 15-25 s, and the pressure is maintained for more than 60 s.

[0012] Preferably, in step (1), the polymerization temperature is 160±10°C, and the polymerization time is 6±2 min.

[0013] Preferably, in step (2), the temperature of the injection mold is 100±10°C, the temperature of the infrared heating is 270±10°C, and the cooling time after injection molding is 40±10 s.

[0014] Preferably, in step (2), the preparation method of the short fiber-reinforced homologous resin composite material is as follows: The same resin material and fiber type as those in the skeleton part are used, and the same short fiber with a weight ratio of 30-60% is added to the resin material. The short fiber is at least one of glass fiber, carbon fiber, and basalt fiber, preferably glass fiber, and then the short fiber-reinforced homologous resin composite material is obtained by co-mixing and extrusion.

[0015] Preferably, the mass ratio of the skeleton part composed of continuous fiber-reinforced reactive nylon to the short fiber-reinforced homologous resin composite material is 40-60 wt%.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The traditional skeleton part generates wrinkles due to hot pressing at large corners, and it is necessary to cut open a notch ( Figure 1 、 Figure 2 ), resulting in discontinuous fibers. After hot pressing and forming, the continuous fibers at the notch are discontinuous, causing a significant decrease in mechanical properties ( Figure 3 、 Figure 4); while the framework member fibers of the present invention are completely continuous, and can even be locally strengthened in places with strong stress; and the formed product of the present invention is an integrated control arm with a three-dimensional structure, without the need to punch holes in the sheet material ( Figure 5 , Figure 6 ) Suspension positioning sheet material, which affects the mechanical properties.

[0017] 2. The polymerization of the present invention occurs in the mold cavity, and customized production of complex workpieces can be carried out; the framework member goes directly from the raw material to the semi-finished product, reducing the process and lowering the cost; the toughness of the framework member can be adjusted by adjusting the formulation ratio; high-pressure in-mold high-pressure injection is adopted, the impregnation time is increased, and the monomer is rapidly penetrated by high pressure drive. At the same time, the pressure can be maintained all the time, resulting in a good appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 Expanded two-dimensional drawing of traditional sheet material; Figure 2 Physical drawing of the expanded traditional sheet material; Figure 3 Three-dimensional drawing after hot pressing and forming of traditional sheet material; Figure 4 Physical drawing after hot pressing and forming of traditional sheet material; Figure 5 The integrated continuous fiber reinforced reactive nylon of the present invention is used as the framework member; Figure 6 Front and back sides of the control arm of the present invention (front side on the left, back side on the right). DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to facilitate the understanding of the present invention, the following will describe the present invention more comprehensively and meticulously in combination with the accompanying drawings of the specification and the preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0021] Unless otherwise defined, all the professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention.

[0022] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments and equipment used in the present invention can be obtained through the market or can be prepared by existing methods.

[0023] The method of the present invention first synthesizes a continuous fiber-reinforced reactive nylon as the skeleton member. The continuous fibers are laid flat in the mold, and a low-viscosity polymerization monomer is injected under high pressure. After complete impregnation, anionic polymerization is initiated to synthesize a high-strength skeleton member of continuous fiber-reinforced reactive nylon. During the forming process of the control arm, the metal insert is first placed in the injection mold. After the skeleton member is heated by infrared, it is transferred into the injection mold and the resin in the skeleton member is maintained in a semi-molten state. At the same time, a short fiber-reinforced homologous resin composite material is injected to form a connecting member with a wrapped edge and a reinforcing rib, and the three, namely the metal insert, the skeleton member, and the connecting member, are integrally formed into an integrated control arm product.

[0024] Example 1: A method for preparing an integrated control arm with a continuous fiber-reinforced reactive nylon as the skeleton member includes the following steps: The first step: Before forming, lay 6 layers of twill glass fiber fabric (fiber content 55wt%) in the skeleton member mold, close the mold, and raise the temperature to 160 °C and keep it. Add 10 kg of caprolactam to the A reactor, and 9.7 kg of caprolactam to the B reactor. The caprolactam materials in the A and B reactors are heated to 140 °C, and the water is removed by vacuum pumping. Then add 40 g of sodium hydroxide to the A reactor and 300 g of 4,4'-diphenylmethane diisocyanate to the B reactor, and vacuum pump again for 10 min to obtain Material A and Material B.

[0025] The second step: The A and B reactors simultaneously pump out the raw materials through a high-pressure pump to inject Material A and Material B. The injection pressure is 15 Mpa, so that caprolactam is fully mixed under high-pressure conditions in the mold and strongly impregnates the continuous fibers. The injection amount of the A and B reactors is 170 g respectively, and the remaining materials in the A and B reactors are used for the next product. The high-pressure injection time is 15 - 25 s, and the pressure is maintained for 60 s.

[0026] The third step: Keep the mold temperature at 160 °C. After reacting for 6 min, open the mold and take out the skeleton member (see Figure 5 ).

[0027] The fourth step: Add glass fiber with a weight ratio of 50% to caprolactam, and then obtain a 50wt% glass fiber-reinforced polycaprolactam modified material through co-blending and extrusion; The fifth step: Place the relevant metal insert in the injection mold, heat the skeleton member to 270 °C by infrared, transfer it to the 100 °C injection mold and keep the resin in the skeleton member in a semi-molten state. Quickly close the mold and inject the 50wt% glass fiber-reinforced polycaprolactam modified material. After cooling for 40 ± 10 s, take out the product to obtain an integrated control arm product (see Figure 6 ).

[0028] Example 2: A method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1, except that in the second step, when injecting Material A and Material B by a high-pressure pump, the injection pressure is 10 Mpa.

[0029] Example 3 A method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1, and the materials in Reactor A are exactly the same as those in Example 1. The difference is only that in the first step, 6.3 kg of caprolactam and 3 kg of laurolactam are added to Reactor B.

[0030] Example 4 A method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1. The difference is only that in the fourth step, the weight ratio of the added glass fiber is 30%.

[0031] Example 5: A method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1, and the materials in Reactor A are exactly the same as those in Example 1. The difference is only that in the first step, 9.3 kg of caprolactam is added to Reactor B, heated to 140 °C, and then 300 g of 4,4'-diphenylmethane diisocyanate and 400 g of a toughening agent, hydroxyl-terminated poly(tetrahydrofuran) ether with Mn = 2000 (the content of the toughening agent is 4 wt%), are added to Reactor B.

[0032] Example 6: A method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1, except that in the first step Figure 1 and Figure 3 At the notch of, one more layer of twill glass fiber fabric is laid for local strengthening (20 mm * 40 mm), forming a scheme with 6 layers in total and 7 layers locally (fiber content 60 wt%). Because this is the stress concentration point during the service process of the product.

[0033] Example 7: A method for preparing an integrated control arm with a continuous fiber reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1. The A reactor is exactly the same as that in Example 1, except that in the second step, 8.3 kg of caprolactam is added to the B reactor, and the temperature is raised to 140 °C. Then, 300 g of 4,4'-diphenylmethane diisocyanate and 3.000 kg of a toughening agent, hydroxyl-terminated polytetrahydrofuran ether with Mn = 2000 (the toughening agent content is 25.86 wt%), are added to the B reactor.

[0034] Example 8: A method for preparing an integrated control arm with a continuous fiber-reinforced reactive nylon as the skeleton member, comprising the following steps: The operation steps are the same as those in Example 1, except that before molding in the first step, 7 layers of twill fiberglass cloth are laid in the mold to increase the fiber content in the skeleton (the fiber content is 70 wt%).

[0035] Four sets of the same continuous fiber-reinforced reactive nylon 6 skeleton member synthesis devices are set up. The rhythm is controlled, and the skeleton member is taken out of the mold. At this time, the temperature is the reaction temperature, and it is immediately transferred to the injection mold, and then the subsequent hybrid injection steps are carried out, so that the semi-continuous operation of the process can be formed.

[0036] Comparative Example 1: The sheet of LANXESS Tepex® continuous fiber-reinforced nylon 6 is cut into the size of a traditional sheet. Relevant metal inserts are placed in the mold. The skeleton member is infrared heated to 270 °C, transferred to the injection mold, the mold is quickly closed, and 50% glass fiber-reinforced polycaprolactam modified material is injected. After cooling for 30 s, the product is taken out to obtain an integrated control arm product.

[0037] Table 1: Comparison of the performance parameters of the integrated control arm products of Examples 1-5 and Comparative Example 1

Claims

1. A method for preparing an integrated control arm using continuous fiber reinforced reactive nylon as a skeleton member, characterized in that: The steps include: (1) Laying the continuous fibers flat in the skeleton mold, raising the temperature to the polymerization temperature, and then injecting a resin composed of low-viscosity polymerization monomers to completely impregnate the fibers and initiate anionic polymerization to form a skeleton composed of continuous fiber-reinforced reactive nylon; (2) First, place the metal insert in the injection mold, transfer the frame member prepared in step (1) into the injection mold after infrared heating, and keep the resin in the frame member in a semi-molten state. At the same time, inject the short fiber reinforced homologous resin composite material to wrap the metal insert while forming a rim and reinforcement ribs on the frame member, and fuse them into an integrated control arm product.

2. The method according to claim 1, characterized in that The weight ratio of the continuous fibers in the skeleton obtained in step (1) is 40-70%; the continuous fibers are fiber fabrics formed by at least one of glass fibers, carbon fibers, and basalt fibers; The continuous fibers are laid in 5-7 layers in the mold, and 1-2 more layers are laid at the stress concentration points during the service life of the product.

3. The method according to claim 1, characterized in that In step (1), the low-viscosity polymerizable monomer is lactam; the low-viscosity polymerizable monomer is first heated to 140°C±10°C before being added to the skeleton mold, and the water is removed by vacuum.

4. The method according to claim 3, characterized in that In step (1), the specific operation of injecting the resin composed of low-viscosity polymerized monomers comprises the following steps: adding a portion of the low-viscosity polymerized monomers to reactor A, adding the remaining portion of the low-viscosity polymerized monomers to reactor B, heating the low-viscosity polymerized monomers in reactors A and B to 140°C±10°C, vacuuming to remove moisture, then adding an alkali catalyst to reactor A, adding a co-catalyst to reactor B, and vacuuming again to obtain material A and material B; Then, material A and material B are injected into the frame component mold at the same time under high pressure, and the weight ratio of material A to material B in the frame component mold is controlled at 0.9-1.1:

1.

5. The method according to claim 4, characterized in that The weight ratio of the low-viscosity polymerization monomer added to the A reactor to the alkaline catalyst is 1000:3-5, and the alkaline catalyst is at least one of sodium hydroxide, potassium hydroxide, and sodium ethoxide; the weight ratio of the low-viscosity polymerization monomer added to the B reactor to the co-catalyst is 93-98:2-3, and the co-catalyst is at least one of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate; a toughening agent is also added to the B reactor, and the weight ratio of the toughening agent in the B material is 1-30%, and the toughening agent is at least one of terminal hydroxyl polytetrahydrofuran ether, terminal hydroxyl polyvinyl alcohol, and terminal hydroxyl polypropylene alcohol.

6. The method according to claim 1, characterized in that In step (1), the injection pressure of the low-viscosity polymer monomer is 10-16 MPa, the injection time is 15-25 s, and the pressure is maintained for more than 60 s.

7. The method according to claim 1, characterized in that In step (1), the polymerization temperature is 160±10° C. and the polymerization time is 6±2 min.

8. The method according to claim 1, characterized in that In step (2), the temperature of the injection mold is 100±10°C, the temperature of the infrared heating is 270±10°C, and the cooling time after the injection molding is completed is 40±10s.

9. The method according to claim 1, characterized in that: In step (2), the preparation method of the short fiber reinforced homologous resin composite material is as follows: using the same resin material and fiber type as those in the skeleton member, adding 30-60% by weight of the same short fiber to the resin material, the short fiber is at least one of glass fiber, carbon fiber, and basalt fiber, and then obtaining the short fiber reinforced homologous resin composite material through blending and extrusion.

10. The method according to any one of claims 1 to 9, characterized in that The mass ratio of the continuous fiber reinforced reactive nylon skeleton to the short fiber reinforced homologous resin composite material is 40-60wt%.

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