JP6241690B2 - Method for making highly finished surface articles made of advanced composite materials - Google Patents

Description

  The present invention relates to a method for producing a highly finished surface article made of an advanced composite material and an advanced composite article produced by the method.

  As is known, in the automotive field, automotive components are routinely classified based on the quality of their surfaces and thus the aesthetic requirements that they must meet.

  Usually, three car classes are identified. That is, class A, class B, and class C.

  Class A relates to a visible automobile part, for example, a hood of an automobile.

  Class B is also a visible part of a car, but its aspect is not considered important, such as a recess in a door opening.

  Class C relates to parts that cannot be seen by the automobile, such as joints for automobile seats.

  Surface quality is evaluated based on a human observing a reflection image of a car body part under controlled illumination conditions.

  Class A surfaces are designed with their folds and tangents aligned to give perfect reflection quality.

  Moreover, Class A surfaces do not contain undesirable undulation patterns and have a continuous fold in each direction.

  This means that the points arranged side by side with a certain line have the same bending radius.

The main drawbacks of advanced composite materials for the creation of Class A car body parts are:
The presence of surface defects such as spots and holes, parts with these are rejected for automotive surface parts;
・ Possibility of peeling;
The presence of bond lines;
-Presence of visible surface undulations.

  In other words, creating a class A surface from advanced composite materials can be much more difficult than conventional approaches.

  This is due to the duality of the component matrix and the reinforcement to it so that the product has much more variables than those of the component materials (eg steel and aluminum). Become.

  Moreover, the reinforcing fibers can produce visible traces on the part surface, which makes the part unusable as a Class A finished surface.

  In this context, it should be pointed out that the surface finish level must be kept constant throughout the life of the vehicle.

  In fact, the aesthetic details of the exterior surface of an automobile must resist aging while continuing to be exposed to atmospheric agents and moist environments, and in addition to the effects of sudden changes in temperature and humidity. It should be almost unresponsive.

  The creation of automotive parts made of advanced composite materials that have high aesthetic properties and meet Class A surface requirements uses additional custom design solutions in the part molding and finishing processes.

  Prior art approaches to achieve the above objectives depend on the automobile part to be produced and the manufacturer's skill and production ability.

  Further aspects relate to one or more of the items described herein below.

  Using one or more polymer films to coat a separation film and a so-called “prepreg”, then place in a mold, spread in a lamination process, and place between mold surfaces.

  In order to spread a so-called “gel coat” on the mold surface, it is necessary to cover the mold with a further resin layer and then laminate a prepreg to be deposited thereon.

  Further machining of molded pieces or parts: further spreading of primer or pre-smoothing operation to eliminate the possibility of surface defects or holes.

  That is, the method of making a Class A composite part further includes one or more additional processing or machining steps that are performed by very long and complex operations, which greatly increases manufacturing costs.

Italian Patent No. IT MI20 110 137 (Patent Document 1) discloses the preamble of claim 1.

Italian Patent No. IT MI20 110 137 Specification

  The goal of the present invention is to provide just that method of creating advanced composite parts with a high degree of surface finish, which is specifically designed to create automotive body parts. .

  Within the scope of the above goals, the main object of the present invention is to provide just that method suitable for the production of automobile body parts with both a very high surface finish and a very high dimensional stability.

  Another object of the present invention is to provide just that article or product made by the method of the present invention with very good impact resistance or resilience and very good stiffness.

  Yet another object of the present invention is to provide just that method that allows automobile body parts to be produced at a much lower cost than the costs of previous production systems and methods.

  In accordance with one aspect of the present invention, the above goals and objectives, as well as other objectives that will become more apparent herein below, are combined with two layers made of advanced composite materials with a high degree of surface finish. This is achieved by a method of forming molded parts, in particular automobile body parts, by molding, which comprises a composite material (or pre-impregnated and bonded with a first layer of fibrous base material by means of a hot melt impregnation machine. A second layer of the prepreg), the second layer being the outermost part of the joined parts, the outermost part being the part that contacts the mold in the molding process, The first layer is impregnated with an impregnating resin system identical and compatible with that impregnating the second layer, and simultaneously with the second layer, polymerization or cross-linking occurs. The method further comprises operating the hot melt impregnation machine at an operating speed of 2 to 4 meters / minute; the resin system comprises hot melt epoxy comprising 40 to 65% by weight of the bonded parts Made of resin.

  The method according to the invention is particularly useful for making automotive body parts from composite materials as raw materials, but can also be used in the marine, sports and aviation fields.

  The method according to the invention greatly reduces or completely eliminates the possibility of visible reinforcing fibers on the surface of the article.

  The above goals and objectives, as well as other objectives that will become more apparent herein below, are also achieved by advanced composite products made by the method of the present invention.

Additional features and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of the preferred, but not exclusive, embodiments of the invention. Embodiments are illustrated in the accompanying drawings, but are by way of example and not by way of limitation:
FIG. 1 shows a table showing the temperature, pressure, heating ramp, and cooling ramp of an autoclave crosslinking cycle according to a first embodiment of the present invention; FIG. 2 is a diagram illustrating the operational steps shown in the table of FIG. 1; FIG. 3 is a further table showing the temperature, pressure, heating ramp, and cooling ramp of an autoclave polymerization or crosslinking cycle according to a second embodiment of the present invention; and FIG. 4 is a further diagram illustrating the operational steps shown in the table of FIG.

  The components of the composite material are separated by a clear and distinct separation interface of substantially zero thickness, each of which has different chemical and physical properties at the macroscopic and structural levels.

  More particularly, the individual components forming the composite material are referred to herein as “matrix” and “reinforcement”.

  The combination or integration of the above components or materials provides a solid continuous material suitable for transmitting and redistributing internal strains due to external stresses.

  The reinforcing material includes a dispersed phase that is variously dispersed in the matrix and is designed to provide a composite material with the desired stiffness and mechanical strength.

  More specifically, the composite material used in the present invention is made of a reinforcing material composed of a dispersed fibrous phase.

  The fiber of this dispersed fibrous phase is a composite material in which the main body is solid and durable in a long stretched shape, that is, has a longitudinal dimension larger than a cross-sectional dimension, and has a desired strength and rigidity. Is to provide.

The reinforcing material can specifically include, by way of example:
Glass fiber;
Carbon fiber (consisting of graphite carbon and amorphous carbon);
Ceramic fibers (eg silicon carbide or alumina) and aramid fibers (such as Kevlar);
-Basalt fiber.

  In order to achieve the desired continuity and strength characteristics, the fibers are combined to form a fiber beam in the form of parallel fiber yarns or twists.

Reinforcing materials used in suitable applications according to the present invention include the following materials:
-Unidirectional reinforcement: fiber beams all arranged in the same direction;
-Multiaxial reinforcement: consisting of overlapping unidirectional reinforcements;
-Fabric: A fabric in which fibers are woven together.

  The matrix includes a uniform continuous phase that acts as a filler material.

  Such a material is initially in the form of a viscous fluid and properly fills all spaces and adheres perfectly to the fiber.

  The matrix is subjected to a solidification process to provide a structure with stability and clear and well-defined geometric properties.

  The types of matrix used in the preferred applications according to the invention consist mainly of polymer matrix composites, such as thermoplastic materials (such as nylon and ABS) or thermosetting materials (such as epoxy resins).

  Integration of the resin and the reinforcing material (consisting of unidirectional, multiaxial, fiber, or textile fabric) may be performed during component preparation by a conventional manual impregnation method, or an article piece may be created. You may carry out in the operation process preceding.

  Materials included in this second class are defined as “pre-impregnated” or “prepreg” materials.

  The fibers forming the material are impregnated by an industrial process. Industrial processes place the impregnating resin in an even manner, in addition to using the appropriate amount of fiber.

  The present invention also provides a combined pre-impregnation that forms the outermost part of the article to be created, i.e., the part that contacts the mold during the article piece molding process, and the finished article piece has highly finished surface properties. Also related to prepreg materials.

  Bonding takes place during the prepreg making process and thus when this prepreg is impregnated, conventional supports made of either unidirectional, multiaxial fibers, or fiber fabrics, and nonwoven materials, felt materials, or the like Associated with a fibrous material layer made of any material having various properties.

  The support and bonded layer can also include carbon fibers, glass fibers, aramid fibers, or any fibers used to make advanced composite materials.

  The preparation of this prepreg further includes a brief heating of the pretreated fibers in a heating oven to provide the first partial cross-linking of the matrix: this operation step completely removes any remaining bubbles. It provides a product with the required density while allowing the material to be further processed without changing its properties.

The fibrous material layer used in such embodiments has the following properties:
The fibrous material layer comprises a group of nonwoven fibers in which fibers having a fiber length of 6-12 mm are randomly arranged;
The fibers are bound with a PVA (polyvinyl alcohol) binder material;
• The fibrous material layer is compatible with the epoxy resin system used in advanced composite materials;
The fibrous material layer is a flat and porous layer that has absorbed the resin in a very good manner;
- fibrous material layer typically has a layer weight in the range of 10 to 50 g / ^{m 2.}

The selected material is impregnated with a modified epoxy resin system by adding appropriate amounts of inert materials such as:
Layered silicates, ie silicon, aluminum and potassium oxide mixtures;
-Hollow glass microparticles with a maximum diameter of 30 micrometers.

  The above properties make such epoxy systems ideal for aesthetic applications. This is because such epoxy systems have improved resistance to aging due to sudden changes in temperature and humidity.

  In addition, the use of inert materials provides the resin system with a covering effect on the fabric while minimizing the surface protrusion of the fibers. Fiber surface protrusion is an unacceptable phenomenon for class A finished surfaces.

  Moreover, the subject system is compatible with other epoxy systems that form the remainder of the article to be manufactured.

  Furthermore, the selected material allows standardized crosslinking operation cycles to be performed, for example, in autoclaves, vacuum bags, and hot presses.

  The finished surface of the parts so produced has a very good surface quality and has a white spot even after processing in a water bath (2 hours in boiling water or 30 days at room temperature). Does not have.

  Moreover, it is possible to obtain class A automotive body parts made of advanced composites directly from the mold, such as, for example, a significant reduction in manual machining time during the part lamination and finishing operation process. Provides great benefits.

  The process is also very simple, quick and inexpensive.

  The connection according to the invention results in a direct connection with the used prepreg while greatly reducing the machining time.

  In fact, during the process of preparing the mold, there is no need to use a polymer film to dispose on the mold surface.

  Moreover, it is not necessary to spread a gel coat on the mold surface during the process of preparing the mold.

  Downstream of the molding process, there is no need for further machining operations on the parts in addition to conventional polishing and painting operations.

  The materials and processes must be accurately designed to provide the desired degree of advanced surface finish throughout the life of the vehicle.

  The use of the above advanced composites not only solves the surface quality and finishing problems, but can further achieve design freedom, thanks to its nature and optimization of the production process, This cannot be achieved by the prior approach using metal materials.

  Specifically, the benefits achieved include optimization of mechanical stress resistance, optimal balance of stiffness to weight ratio, and improved flexibility in designing automotive body parts.

  The polymerization / crosslinking cycle described above is a process in which the resin of the prepreg changes from a liquid state to a solid state by heating.

  Standard processing methods involve crosslinking cycles in an autoclave, hot press, or vacuum bag.

  The operation steps of each processing cycle are briefly described herein below.

Polymerization or cross-linking temperature and time Different cross-linking temperatures and times can be used for each prepreg resin system.

  The entire prepreg part, and the associated mold, must be maintained at the crosslinking temperature for the time required by whatever resin system is required.

  The heating rate is a measure of the time required for the part being made to reach the polymerization or crosslinking temperature.

This operating process is controlled by various parameters, for example:
Matrix viscosity;
-Matrix reaction time;
・ Thickness of parts to be created;
• Mold inertia and thermal conductivity.

  The cooling rate or rate is controlled so that any sudden temperature change does not cause mechanical stress in the composite part.

  The operating steps defined for each of the various crosslinking cycles of each resin system, and the associated vacuum and pressure conditions, should be either applied or removed.

  The adequacy of this solution for the intended purpose is an aesthetic finish in direct contact with atmospheric agents, in particular achieved by painting, in the color of the car, or any desired color effect, coloration And by means of evaluating parameters adapted to the aesthetic components of the exterior surface of the vehicle.

  The created parts have undergone further visual inspection at the end of the accelerated aging procedure disclosed herein below.

  More specifically, visual inspection assesses the appearance of the part under test: the requirements to be met are that the surface of the part being inspected is continuous and uniform, surface defects and aesthetic defects. It is not to have.

The accelerated aging procedure used a climate chamber with the following operating cycle herein:
・ Humidity resistance:
20 cycles of 12 hours; in each cycle the temperature is maintained at 40 ° C. and the relative humidity at 98%;
-Resistance to temperature changes:
-20 12-hour cycles.

Each cycle includes:
1) Maintain the temperature at 23 ° C. and the relative humidity at 30% for 40 minutes;
2) Switch the temperature to 35 ° C in 90 minutes;
3) maintain the temperature at 35 ° C. for 60 minutes;
4) In 80 minutes, further switch the temperature to 45 ° C. and the relative humidity to 80%;
5) Maintain the temperature at 45 ° C. and the relative humidity at 80% for 120 minutes;
6) In 30 minutes, switch the temperature to 90 ° C. and the relative humidity to 30%;
7) Maintain the temperature at 90 ° C. and the relative humidity at 30% for 240 minutes;
8) In 60 minutes, switch the temperature to 23 ° C. and the relative humidity to 30%.

  Downstream of the above disclosed procedure, no surface variations such as spots, blistering, or any other aesthetic finish modifications were observed.

Example 1
Impregnation with woven and non-woven carbon binder and modified epoxy resin.

Carbon fabric or fabric material: 2 × 2 twill, weight 180-400 g / m ² (A);

Carbon nonwoven material: weight 20-50 g / m ² (B);

The properties of the epoxy resin were as follows:
Volatile substances in prepreg (% wt) <1
Resin density (g / cm ³ ) 1.2
Tg (DSC) ^* (° C.) 135 TgE ′ (DMA) ^** (° C.) 125 Tan δ peak Tg (DMA) ^** (° C.) 146
^* Dynamic scanning measurement
^** Completely cross-linked laminate

Temperature (℃) Gelation time (min)
100 87
110 56
120 21
130 8.75

  Resin content: 45% to 65% of the final weight of the entire combined and impregnated material.

Impregnation and Bonding Process The impregnation process of the binding material A + B in this example is performed in two successive process steps, using a hot melt impregnation machine at a rate of 2-4 meters / minute:
1) Step of impregnating carbon fabric A (with support function): The amount of resin deposited on the support corresponds to 40% to 50% of the final weight of the impregnated fabric; the cylinder pressure is 2-6 bar Configuration;
2) Carbon non-woven material B and this support A are bonded together, and this non-woven material is impregnated with an impregnating resin having the same composition as that used in the preceding step or process. Impregnation in an amount of 70% to 90%; the cylinder pressure is set to 1 to 4 bars.

Possible stacking sequences suitable for use in the solution disclosed in the above example include the following:
1) Solution A + B for bonding woven / nonwoven materials made as disclosed above;
2) Carbon fabric or woven material B impregnated with an impregnating resin having a composition comparable to that previously disclosed.

The method according to this exemplary embodiment includes making an automobile body part as generally disclosed herein below, starting from the outside of the finished part and thus from the mold surface:
1. [0 ° C] 1 carbon non-woven material + carbon woven material (A + B)
2. [90 ° C] 5-carbon fabric material (B)

Proposed Autoclave Crosslinking Operation Cycle Possible possible crosslinking cycles that provide an efficient solution are disclosed herein below.

  This sequence of operations depends on the resin system used, so this is given as an example only and not a limiting example. This is because this sequence of operations is a unique property of the epoxy resin used in the process disclosed herein.

  The proposed process steps are disclosed in the table of FIG. 1, where the temperature, pressure, heating ramp, and cooling ramp are shown; the cross-linking operation to maximize the aesthetic yield of the surface in contact with the mold When the cycle is carried out in an autoclave, it is necessary to properly release the reduced pressure.

  The graphic of FIG. 2 illustrates the operational process disclosed in the previous table.

Example 2
Bonding material of unidirectional reinforcement (UD) and carbon nonwoven; Impregnation with modified epoxy resin:
Unidirectional carbon reinforcing material: weight 120-400 g / m ² (C);
Carbon nonwoven material: weight 15-70 g / m ² (D);

Characteristics of epoxy resin:
Volatile substances in prepreg (% wt) <1
Resin density (g / cm ³ ) 1.23
Tg (DSC) ^* (° C.) 181 TgE ′ (DMA) ^** (° C.) 167 Tan δ peak Tg (DMA) ^** (° C.) 184
^* Dynamic scanning measurement
^** Completely cross-linked laminate

Temperature (℃) Gelation time (min)
80 400
100 85
120 17
135 5.5
150 4

  Resin content: 40% to 60% of the final weight of the entire combined and impregnated material.

Impregnation and Bonding Process The impregnation process for impregnating the binding material C + B of this example is performed in the following two different process steps, using a hot melt impregnation machine at a speed of 2-4 m / min:
1) impregnation with unidirectional carbon reinforcing material C (having a supporting function): the amount of resin deposited on the support corresponds to 30% to 40% of the final weight of the impregnated reinforcing material;
2) Bond the carbon nonwoven material D and the previous support C, and impregnate it with the impregnating resin having the same composition as that used in the preceding step or process. Impregnation is carried out in an amount of% to 90%.

Possible stacking sequences proposed Possible stacking sequences in this specification that are proposed for use in the solution of this example include the following:
1) Solution C + D combining UD / nonwoven materials made as disclosed above;
2) A carbon woven or fabric material similar to Type B disclosed in Example 1 impregnated with a resin having a composition compatible with the preceding.

This process involves making an automotive body part as disclosed generally herein below, starting from the outside of the finished part and hence from the mold surface:
1. [0 ° C] 1 carbon nonwoven material + UD reinforcement (C + D)
2. [90 ° C] 4-carbon woven material (B)
Or alternatively:
1. [0 ° C] 1 carbon nonwoven material + UD reinforcement (C + D)
2. [90 ° C] 2-carbon fabric material (B)
3. [90 ℃] 1UD reinforcement material (C)

Possible proposed autoclave cross-linking cycles are disclosed herein below as possible cross-linking cycles that provide an efficient solution.

  This sequence of operations is a characteristic example and depends strictly on the resin system used and should therefore be regarded as illustrative only. This is because this sequence of operations is a unique property of the epoxy resin used in the process disclosed herein.

  The proposed process steps are shown in the table of FIG. 3, where the temperature, pressure, heating ramp, and cooling ramp are shown; the crosslinking operation cycle to maximize the aesthetic yield of the surface in contact with the mold If this is done in an autoclave, the release of decompression must be carefully judged.

  The graphic of FIG. 4 illustrates the process disclosed in the previous table.

  Thus, it has been found that the present invention fully achieves its intended goals and objectives.

  In practicing the present invention, the materials used, and the attendant sizes and shapes, can be any as required.

Claims (14)

And shaping in molds, two-layer connection element with a high degree of surface finish, in particular how to create advanced composite material suitable for forming a car body, the method, by the hot melt impregnation machine, fiber Bonding a first support layer of the substrate to a second bonded layer of a pre-impregnated and bonded composite or prepreg, the second layer forming the outermost portion of the bonded component, I.e. the part in contact with the mold in the molding process and, in the finished state, the part having a high degree of surface finish properties; the first layer is identical to that impregnating the second layer and Impregnated with a suitable impregnating resin system and simultaneously polymerized or cross-linked with the second layer; the method also operates the hot melt impregnation machine at an operating speed of 2-4 meters / minute The resin system , It is made of a hot melt epoxy resin, which accounts for 40-65% of the weight of the coupling component, nonwoven fibers, fiber length and and PVA (polyvinyl alcohol) having a 6~12mm binder material in the binder As well as the epoxy resin system:
Layered silicates, ie silicon, aluminum and potassium oxide mixtures;
-Hollow glass microparticles with a maximum diameter of 30 micrometers,
A method characterized in that it has been modified by adding one or more inert materials consisting of:   The first support layer comprises unidirectional, multiaxial fibers, or woven material, felt material, or any other material with similar properties, and the first support layer and the second tie layer are The method of claim 1, comprising carbon fiber, glass fiber, aramid fiber, or other fiber suitable for making advanced composite materials. The first support layer is a fibrous material layer composed of randomly arranged non-woven fibers compatible with the resin system, and the fibrous material layer is flat and porous and has a weight. The method according to claim 1, wherein the method is 10 to 50 g / m ² .   The method according to claim 1, wherein the epoxy resin is a thermosetting resin. The epoxy resin system has the following characteristics:
Volatile substances in prepreg (% wt) <1
Resin density (g / cm ³ ) 1.2
Tg (DSC) ^* (° C.) 135 TgE ′ (DMA) ^** (° C.) 125 Tan δ peak Tg (DMA) ^** (° C.) 146
^* Dynamic scanning measurement
^** Completely cross-linked laminate temperature (° C) Gelation time (min)
100 87
110 56
120 21
130 8.75
Have
2. The method according to claim 1, characterized in that the resin content is 45% to 65% of the final weight of the entire bonded part. The epoxy resin system has the following characteristics:
Volatile substances in prepreg (% wt) <1
Resin density (g / cm ³ ) 1.23
Tg (DSC) ^* (° C.) 181 TgE ′ (DMA) ^** (° C.) 167 Tan δ peak Tg (DMA) ^** (° C.) 184
^* Dynamic scanning measurement
^** Completely cross-linked laminate temperature (° C) Gelation time (min)
80 400
100 85
120 17
135 5.5
150 4
Have
The process according to claim 1, characterized in that the resin content varies from 49% to 60% of the final weight of the whole combined and impregnated material. The method, the fabric (A) and non-woven (B) a step of creating a binding material carbon, and the binding material, the 2 × 2 twill weave and weight of 180~400g / ^{m 2} the carbon fabric material Impregnating with an epoxy resin system modified by (A), wherein the carbon nonwoven material (B) has a weight of 20-50 g / m ² ;
The epoxy resin has the following characteristics:
Volatile substances in prepreg (% wt) <1
Resin density (g / cm ³ ) 1.2
Tg (DSC) ^* (° C.) 135 TgE ′ (DMA) ^** (° C.) 125 Tan δ peak Tg (DMA) ^** (° C.) 146
^* Dynamic scanning measurement
^** Completely cross-linked laminate temperature (° C) Gelation time (min)
100 87
110 56
120 21
130 8.75
Have
The process according to claim 1, characterized in that the resin content varies between 45% and 65% of the final weight of the total impregnated bonded material. The impregnation step of the binding material A + B is performed using a hot melt impregnation machine at a speed of 2-4 m / min , the following:
1) impregnating the carbon woven material A with an impregnating resin in an amount of 40% to 50% of the final weight of the impregnated fabric at a machine cylinder pressure of 2-6 bar ;
2) by binding the carbon nonwoven material B wherein the carbon fabric material A, the non-woven material B, and the machine of the cylinder pressure 1～4Bars, an amount of 70% to 90% of said non-woven material by weight Impregnating with the impregnating resin ;
Carried out by at least two consecutive process steps including
Possible stacking orders are:
1) Said woven / nonwoven material A + B;
2) was impregnated with impregnating resin which is compatible, the carbon nonwoven material B
The method according to claim 7 , wherein: The method starts from the outside of the finished part, and thus from the mold surface, the following:
1. Carbon non-woven material + carbon woven material (A + B)
2. Carbon fabric material (B)
9. The method of claim 8, comprising the steps of: and performing an autoclave crosslinking step . The method comprising the step of using unidirectional (UD) reinforcement binding material, a carbon nonwoven materials, and modified for impregnation epoxy resin:
Unidirectional carbon reinforcing material: weight 120-400 g / m ² (C);
Carbon nonwoven material: weight 15-70 g / m ² (D);
Characteristics of epoxy resin:
Volatile substances in prepreg (% wt) <1
Resin density (g / cm ³ ) 1.23
Tg (DSC) ^* (° C.) 181 TgE ′ (DMA) ^** (° C.) 167 Tan δ peak Tg (DMA) ^** (° C.) 184
^* Dynamic scanning measurement
^** Completely cross-linked laminate temperature (° C) Gelation time (min)
80 400
100 85
120 17
135 5.5
150 4
Resin content is characterized <br/> from 40% to 60% of the final weight of the total material impregnated bound or laminated, The method of claim 1. The method includes the step of performing impregnation and bonding process, wherein the said impregnation of the binding material C + D, using the hot melt impregnation machine at 2 to 4 m / min, two successive different process stages:
1) a step of unidirectional carbon reinforcement support C, is impregnated with impregnating resin in an amount to deposit 30% to 40% of the final weight of the reinforcing material with immersed including;
2) A step of bonding the carbon nonwoven material D and the support C and impregnating with the same impregnating resin in an amount of 70% to 90% of the weight of the impregnated nonwoven material ,
The method according to claim 10 , wherein the method is performed. The method further includes:
1) Said UD / nonwoven binding material C + D;
2) impregnated carbon fabric material, the material is impregnated with a resin compatible with the impregnation resin,
The method according to claim 11 , further comprising sequentially laminating the layers. 13. The method of claim 12 , further comprising the step of creating an automobile body part , starting from the outside of the finished part, and thus from the mold surface.
1. [0 ° C] 1 carbon nonwoven material + UD reinforcement (C + D)
2. [90 ° C] 4-carbon woven material (B)
Or alternatively:
1. [0 ° C] 1 carbon nonwoven material + UD reinforcement (C + D)
2. [90 ° C] 2-carbon fabric material (B)
3. [90 ° C.] 1UD reinforcement (C). 14. A method according to claim 13 , characterized in that the method comprises a multi-stage autoclave crosslinking cycle .