Molding materials

Abstract

The present invention relates to a molding material comprising a) a primary nonwoven fiber layer; b) a secondary nonwoven fiber layer; and c) a resin layer, wherein the resin layer bonds the secondary nonwoven fiber layer to a first surface of the primary nonwoven fiber layer and the resin layer is exposed on a second surface of the primary nonwoven layer.

Description

Technology Field

[0001] The present invention relates to a molding material, specifically, but not exclusively, a molding material for surface application. Background Technology

[0002] The present invention relates to a molding material that provides a reinforced surface finish, a use of the molding material for forming a laminate structure in combination with one or more pre-impregnated fiber reinforcement (prepreg) layers, a use of the molding material for forming a laminate structure in combination with a dry (non-impregnated) fiber layer, and a method of forming a laminate structure using the molding material. Specifically, the present invention relates to a fiber-reinforced composite molding material comprising a surface finish layer that can be cured at low temperatures and, in particular but not exclusively, provides a molded article having a high-quality surface finish requiring minimal manufacturing after curing for use in the wind turbine and automotive industries.

[0003] Composite materials possess well-proven advantages over typical building materials, specifically in that they provide excellent mechanical properties at very low material densities. As a result, the use of these composite materials has become widespread in numerous industries, including the aerospace, automotive, marine, and wind turbine industries.

[0004] Prepregs comprising fiber arrays impregnated with a thermosetting resin, such as epoxy resin, are widely used in the production of the composite material. Typically, multiple layers of the prepreg are "laid up" as desired, and the resulting assembly, or laminate, is placed in a mold and cured under pressure, typically by exposure to an elevated temperature, to produce a cured composite laminate. In an alternative manufacturing technique, the fiber material is typically laid up within an enclosure, into which a liquid resin system is injected to surround the fiber material, which can then be cured to produce a finished article. The enclosure can be formed around the fiber material and resin drawn under vacuum (sometimes known as vacuum bag technique). Alternatively, the enclosure can be a mold, and the resin can be injected into the mold (sometimes known as resin transfer molding), which can also be vacuum-assisted (known as vacuum-assisted resin transfer molding). As with the system described above in relation to prepreg, the liquid resin system may be an epoxy resin, a cyanate ester resin, or a bismaleimide resin, and it will also contain a curing agent for the specific resin.

[0005] However, without any surface treatment, composite materials produced by one of the aforementioned technologies often harden to provide a poor surface finish, which can appear as a rough, wavy, or pinhole-filled surface, or as narrow grooves on the surface of molded structures where adjacent layers of prepreg are overlapped to ensure a continuous layer. This tendency to form an uneven surface appears to be closely related to the roughness of the base reinforcement, and the problem becomes more pronounced the rougher the reinforcement is. This can be particularly problematic when rough reinforcement is used for structural stiffness but a smooth surface finish is desired, such as in the production of automotive body panels requiring a Class A finish or in the production of blades for wind turbines.

[0006] GB2445929 discloses a fiber-reinforced composite molding comprising a surface portion laminated to a structural portion, wherein the surface portion is formed as a surface layer comprising a plurality of surface layer segments molded together to form a continuous surface layer, the surface layer comprises a first cured resin material supported on a carrier of sheet material, the structural portion is formed from at least one layer of a fiber-reinforced material and a second cured resin material, and at least one layer of the fiber-reinforced material is formed as a plurality of segments each placed on top of the surface layer segment, and each surface layer segment overlaps with an adjacent segment of the fiber-reinforced material.

[0007] These moldings were found to still have poor surface quality due to the evident print-through of the base carrier material and fiber reinforcement material. Additionally, the lay-up requires overlapping, which consequently results in surface defects in the form of visible seam lines.

[0008] WO2008 / 007094 of FIG. 2 discloses a surface material comprising a resin layer and a surface layer comprising a bale and a fleece layer. The resin layer is in contact with the mold surface, and the bale is attached thereto. The fleece contains a resin strip that facilitates bonding the fleece layer to the bale, thereby causing the fleece layer to be partially impregnated with the resin. Such a material has the problem that the resin content of the surface layer is low, so any subsequent prepreg layer must have an increased resin content. This means that prepreg materials having a resin content significantly higher than usual (typically exceeding 60 wt%) can only be used in combination with this surface material, which is complex, inefficient, and costly. Furthermore, the manufacture of the fleece layer having the resin strip is complex and, therefore, inefficient and costly, as the reinforcing layer is typically impregnated across its entire surface.

[0009] WO 2017 / 021147 discloses a surface material comprising a surface layer comprising a resin layer sandwiched between a bale and a fleece layer in FIG. 2. The bale layer is in contact with the mold surface, and the bale and fleece layers are attached to the resin layer so that the bale and fleece layers are mostly not impregnated. This facilitates the release of any air trapped in the lay-up near the mold surface. Such a material has the problem of being complex, inefficient, and costly because the resin content of the surface layer is still low, so any subsequent prepreg layer must have an increased resin content.

[0010] The present invention aims to eliminate or at least alleviate the aforementioned problems and / or generally provide improvements.

[0011] explanation

[0012] According to the present invention, a molding material as defined in any of the appended claims, preferably a surface material, a use of the molding material, and a method for manufacturing a laminate structure are provided.

[0013] The present invention

[0014] a) Primary nonwoven fiber layer;

[0015] b) secondary nonwoven fiber layer; and

[0016] c) Resin layer

[0017] As a molding material including,

[0018] A molding material is provided in which a resin layer bonds a secondary nonwoven fiber layer to a first surface of a primary nonwoven fiber layer, and the resin layer is exposed on a second surface of the primary nonwoven layer.

[0019] Surprisingly, it has now been found that having a resin layer exposed on the surface of the molding material of the present invention in combination with a nonwoven fiber layer provides excellent surface quality without pinholes. Furthermore, it has been found that the appearance of cosmetic defects caused by print-through of the carbon fiber reinforcement layer is prevented by the composition of the molding material of the present invention.

[0020] The material of the present invention also provides an excellent surface finish when used as a mold or tool contact layer when manufacturing laminate products using pre-impregnated and / or non-impregnated reinforcing materials in prepreg or injection systems.

[0021] In addition, it has been found that the prepreg reinforcement layer can be used with such materials having a resin content of 30% to 45% by weight of prepreg without causing any adverse effects on the aesthetic quality of the surface. This enables the use of standard prepreg materials combined with such molding materials, which can prevent an increase in resin content.

[0022] In a specific embodiment of the present invention, the molding material of the present invention may be provided as a surface finishing layer, that is, without any reinforcing layer; thus, in this embodiment, the molding material may essentially be composed of a primary nonwoven fiber layer, a secondary nonwoven fiber layer, and a resin layer as essential elements. In an alternative embodiment, the molding material may be provided as a reinforced surface finishing layer, and in this embodiment, the molding material may include a reinforcing layer, and the secondary nonwoven layer is located between the primary nonwoven fiber layer and the reinforcing layer.

[0023] Specific explanation

[0024] Specific embodiments of the present invention will now be described in more detail as follows by way of example.

[0025] In the molding material of the present invention, the resin layer bonds the secondary nonwoven fiber layer to the first surface of the primary nonwoven fiber layer, and the resin layer is exposed on the second surface of the primary nonwoven layer, so that the primary nonwoven fiber layer is generally completely saturated with the resin. In addition, in a given embodiment, the secondary nonwoven fiber layer is at least partially impregnated with the resin of the resin layer and optionally completely impregnated.

[0026] In a specific embodiment of the present invention, the resin layer comprises a formulated resin matrix comprising at least one resin component, at least one curing agent, and optionally a filler.

[0027] The formulated resin matrix forming the resin layer may comprise a thermosetting resin such as a polyester resin, a polyurethane resin, a polyurethane / polyurea resin, a phenol-formaldehyde resin, a urea-formaldehyde resin, a vinyl ester resin, a cyanate ester resin, a polyimide resin, or an epoxy resin. Unlike thermoplastic resins, thermosetting resins cure irreversibly upon curing, so that any molded article produced therefrom becomes resistant to deformation. In one embodiment, the first resin composition is a thermosetting resin composition, preferably an epoxy resin composition, that is, an epoxy resin composition comprising an epoxy resin or a combination of epoxy resins.

[0028] The resin layer preferably comprises at least a multifunctional bisphenol epoxy resin material in combination with a urea-based curing agent. A preferred formulation resin matrix for this layer is M79 resin supplied by Hexcel Corporation.

[0029] In another embodiment of the present invention, the formulated resin matrix comprises 1 to 10 weight percent of a filler, preferably a silica filler or a lipophilic phylosilicate, preferably a fumed silica filler having a tap density of 60 g / l, based on the weight of the formulated resin matrix. A preferred filler material is Aerosil R202 supplied by Evonik Industries.

[0030] It has been found that the inclusion of fillers reduces the flow of favorable resin layers in layups involving substantial vertical surfaces, such as in the manufacture of ship and yacht hulls.

[0031] The primary and secondary nonwoven fiber layers of the present invention preferably have the following properties and characteristics. The nonwoven fiber layers may contain any nonwoven material permeable to both air and resin. A suitable nonwoven fiber carrier is lightweight, preferably at least 100 g / m²2 It is less than, but preferably, rigid enough to carry the resin layer and withstand handling during lay-up and processing, forming a composite part with a high-quality aesthetic surface.

[0032] The nonwoven fiber layer may include continuous or discontinuous fibers.

[0033] In one embodiment, the primary nonwoven layer comprises a veil. In the context of the present invention, the term "veil" refers to a thin, lightweight (i.e., 100 g / m²) 2 It refers to porous nonwoven fabrics, webs, or fiber reinforcements (area weight below).

[0034] In a preferred embodiment, the primary nonwoven layer typically consists of nonwoven fibers of a thermoplastic material, preferably fibers bonded together using an organic binder to impart structural integrity to the material. In a specific embodiment, the thermoplastic material comprises a polyester, a polyamide, preferably an aliphatic or semi-aromatic polyamide, and / or a combination of a polyester and a polyamide. The organic binder, if present, is typically present in an amount of 1 to 10 weight percent based on the total weight of the primary nonwoven layer.

[0035] The purpose of the primary nonwoven layer is to act as a support or carrier for the resin layer, to retain the resin on an external surface, and to control the way the resin interacts with the surface of the mold or tool to provide a good surface finish.

[0036] In one embodiment, the primary nonwoven material has an openness of 1 to 10%, preferably 2 to 89%, and / or 75 to 350 μm. 2 It has an average open area.

[0037] In a further embodiment, the primary nonwoven fiber layer is 1 to 80 g / m² 2 , preferably 5 to 50 g / m² 2 , more preferably 15 to 40 g / m²2 It has an area weight within a range.

[0038] In one embodiment, the primary nonwoven fiber layer has an output of approximately 2,300 L / m² at an applied pressure of 200 Pa. 2 It has an air permeability of / s (when measured according to ASTM D737-18). Suitable thermoplastic fiber materials in bale form that can be used as a primary nonwoven fiber layer are from Technical Fiber Products Limited (Burnside Mills, Kendall, Cumbria, UK), for example, under the trade name Optiveil T2761-00. ® Includes commercially available items.

[0039] Openness measurements can be performed using a Keyence VHX-6000 series digital microscope manufactured by Keyence (UK) Limited (Milton Keynes, Buckinghamshire, UK). The nonwoven material can be displayed on the microscope mounted on a blue plastic card to help highlight the open area when viewed on a computer monitor. The microscope is set to 175x magnification with maximum light output and a gain dial setting adjusted to clearly identify the open area. The saved computer image is 2951002 μm 2 Represents the total area of.

[0040] Keyence software is then used to measure the average "open area" (i.e., the empty space between fibers) and the openness percentage. The image is also manipulated by adjusting a slider on the histogram to generate a two-color image where one color represents the fibers and the other represents the open space. The software is then used to measure the area of ​​every individual open space. This data is stored in a spreadsheet and can be used to calculate the total area occupied by the open spaces (to calculate the openness percentage), along with the average size of the open spaces.

[0041] The secondary nonwoven fiber layer may comprise a nonwoven fiber material containing continuous fibers or discontinuous fibers. The secondary nonwoven fiber material may comprise nonwoven fibers of glass, carbon, polyester, polyamide, aramid (aromatic polyamide), or a combination thereof, which are optionally bonded together using an organic binder to impart structural integrity to the material. Preferably, the secondary nonwoven fiber layer comprises a glass fiber material, a polyester material, a polyolefin polymer material, and / or a combination of the aforementioned materials.

[0042] Preferably, the secondary nonwoven fiber carrier comprises a nonwoven glass fiber material in bale form. If present, an organic binder may be present in an amount typically of 1 to 10 weight percent based on the total weight of the secondary nonwoven fiber carrier. Generally, the secondary nonwoven fiber material may have a slightly higher area weight or surface density than the primary nonwoven fiber layer. In a preferred embodiment, the secondary nonwoven fiber is 20 to 100 g / m² 2 The range of, more preferably 30 to 80 g / m² 2 The range of, more preferably 30 to 60 g / m² 2 It has an area weight within the range of. Suitable non-woven glass bales, mats, or fleece are Evalith ® Trademark name Evalith from Johns Manville (Denver, Colorado, USA), including but not limited to ST-3022, S 4030, and S 5030 ® , and Changhai ® Trademark name Changhai from Taishan Fiberglass Inc. (Economic Development Zone, Tai'an, Shandong, PR China), including but not limited to S-SM30, S-SM50, S-HM30, and S-HM50. ® It is commercially available.

[0043] The presence of the second nonwoven fiber material helps prevent "print-throughs" from the fiber reinforcement material of the structural reinforcement layer from appearing on the surface of the molding material after curing, and also ensures that a sufficient amount of the second resin composition is maintained within the surface enhancement layer during curing to prevent the formation of narrow grooves or other surface irregularities due to resin depletion. Like the first nonwoven fiber material, the second nonwoven fiber material can also serve to prevent air trapping or to help dissipate trapped air.

[0044] In a specific embodiment of the present invention, the molding material does not include any reinforcing material, and thus the molding material is composed of a primary nonwoven fiber layer, a secondary nonwoven fiber layer, and a resin layer as essential elements.

[0045] In an embodiment of the present invention according to the first aspect without reinforcing material, the total resin content of the molding material may be contained in the resin associated with the primary nonwoven layer. The preferred total resin content of the molding material in this embodiment will depend on the intended use of the molding material, but preferably the resin content of the molding material is in the range of 40 to 75 weight% based on the weight of the molding material, more preferably 50 to 60 weight% based on the weight of the molding material.

[0046] In a second aspect of the present invention, the molding material of the present invention comprises a reinforcing layer, and a secondary nonwoven fiber layer is located between the primary nonwoven fiber layer and the reinforcing layer. The presence of the reinforcing layer helps to improve the structural integrity of the molding material, which facilitates storage, transportation, and handling.

[0047] Preferably, a secondary nonwoven fiber layer is stitched onto the surface of the reinforcing layer. The layer may be stitched with polyester yarn having a tex value in the range of 5 to 90 dtex, preferably 40 to 85 dtex, and more preferably 70 to 85 dtex.

[0048] The structural reinforcement layer may be in multiple forms. Generally, the molding material according to the second aspect of the present invention will contain various structural reinforcement layers, but for some applications, a single layer may be sufficient.

[0049] The fiber reinforcement material may be in the form of a sheet, a continuous mat, or a continuous filament. In another embodiment, the fiber reinforcement material comprises short-length fibers, for example, a chopped strand mat. The fiber reinforcement material may be in the form of a multi-fiber tow, each containing multiple fiber filaments to form a tow. The tows may be stitched or woven to form a fabric. The fibers may consist of natural materials such as cotton, linen, hemp, wool, or silk; semi-synthetic materials, such as rayon, viscose, modal, etc.; or synthetic materials, such as carbon, polyester, mineral, nylon, acrylic, glass, aramid (aromatic polyamide), etc. In a preferred embodiment, the fiber reinforcement material comprises carbon fibers or glass fibers.

[0050] In some embodiments, the fiber reinforcement material is in the form of a woven fabric. In other embodiments, the fiber reinforcement material comprises a unidirectional (UD) fabric, wherein a majority of the fibers, rovings, or tows present in the fabric proceed in only one direction, but a minority of the fibers, rovings, or tows may proceed in a number of different directions, such as cross-stitches, to maintain the latter unidirectional alignment. The fibers, rovings, or tows of the unidirectional fabric may be maintained in an aligned state by a number of different methods, including weaving, stitching, and bonding. Consequently, such a unidirectional fabric may be a woven fabric or a nonwoven fabric. In additional embodiments, the fiber reinforcement material comprises a unidirectional fabric combined with a biaxial or multiaxial fabric or mat, wherein either component may be a woven fabric or a nonwoven fabric.

[0051] Suitable woven and nonwoven fabrics for use in composites are commercially available from specialized manufacturers including, but not limited to, Chomarat Textiles Industries (Isher, Surrey, UK), Hexcel Reinforcements UK Limited (Naborough, Leicestershire, UK), and Zhenshi Group Hengshi Fibreglass Fabrics Co., Ltd. (PR China Tongxiang Economic Development Zone, Jiaxing, Zhejiang, 314500 China). In one embodiment, the woven or nonwoven fabric is a carbon fiber or glass fiber fabric such as BB200, BB600, or BB1200, wherein the designation BB1200 is, for example, 1200 g / m² 2 It refers to a biaxial glass fabric having an area weight.

[0052] Hybrid or mixed fiber systems may also be considered. The use of cracked (i.e., stretch-break) or optionally discontinuous fibers may be advantageous for facilitating the lay-up of the molding material according to the present invention and improving its moldability.

[0053] The area weight of fiber-reinforced materials is generally 40 to 4,000 g / m² 2 is. In a preferred embodiment, the area weight of the fiber is preferably 100 to 2,500 g / m² 2 , more preferably 150 to 2,000 g / m² 2 It is the range of.

[0054] Fiber reinforcement materials in structural reinforcement layers, or in structural reinforcement layers where one or more layers exist, will typically be heavy non-cream fabrics such as glass fabric. For glass reinforcement, fibers of 68 to 2400 tex (grams per kilometer of yarn) are particularly suitable.

[0055] In a specific embodiment of the second aspect of the present invention, the reinforcing layer may comprise at least two layers, each containing unidirectional fibers. The unidirectional fibers of each layer may have different directions.

[0056] In one embodiment, the unidirectional fiber layer and the secondary nonwoven fiber layer are optionally stitched together using the same stitch yarn.

[0057] The reinforcing layer preferably comprises a fiber reinforcing material and a formulated reinforcing resin matrix, and in a preferred embodiment, the formulated reinforcing resin matrix has the same composition as the resin of the resin layer.

[0058] In an embodiment of the present invention according to a second aspect having a reinforcing layer, the total resin content of the molding material may be contained in the resin associated with the primary nonwoven layer, or the resin may be distributed throughout the material as a plurality of individual layers or as a single matrix. The preferred total resin content of the molding material in this embodiment will depend on the intended use of the molding material and also the weight of the reinforcing material, but preferably, the resin content of the molding material is in the range of 5 to 60 weight% based on the weight of the molding material. For example, in a molding material intended for use in an injection system, the total resin content is preferably 5 to 50 weight% based on the weight of the molding material, and more preferably 5 to 20 weight%. Similarly, in the case of a molding material intended for use in combination with a material that is at least partially pre-impregnated without injection, the total resin content is preferably 20 to 60 weight% based on the weight of the molding material, and more preferably 25 to 50 weight%.

[0059] The present invention provides a use of the molding material of the present invention for forming a laminate structure in combination with one or more pre-impregnated fiber reinforcement (prepreg) layers, wherein the prepreg layers have a resin content in the range of 30% to 45% based on the weight of the prepreg material.

[0060] The present invention further provides a use of the molding material of the present invention for forming a laminate structure by a resin injection process in combination with one or more resin-free (dry) layers of fiber reinforcement.

[0061] The present invention also provides a method for manufacturing a laminate structure, said method

[0062] A step of placing a molding material according to the present invention on the surface of a mold or tool by bringing a resin layer exposed on a second surface of a primary nonwoven fabric fiber layer into contact with the surface of a tool or mold;

[0063] A step of forming a stack by applying one or more layers of resin-free (dry) fiber reinforcement to opposite surfaces of the molding material;

[0064] Step of injecting injection resin into the stack; and

[0065] It includes a step of hardening the injected stack.

[0066] In the method for manufacturing a laminate structure of the present invention, the molding material used in the method may be a molding material according to the first aspect of the present invention, i.e., a molding material that does not include a reinforcing layer. Alternatively, the molding material may be a molding material of the second aspect of the present invention, i.e., the molding material includes a reinforcing layer, and specifically, the molding material includes a reinforcing layer in which the resin content of the molding material is in the range of 5 to 50 weight%, preferably in the range of 5 to 20 weight% based on the weight of the molding material.

[0067] In the method for manufacturing a laminate structure according to the present invention, at least one of the fiber reinforcement (prepreg) layers pre-impregnated before resin injection may be included in the stack.

[0068] In the method for manufacturing a laminate structure according to the present invention, any conventional injection process and injection resin may be used depending on the intended use of the laminate structure.

[0069] floor plan

[0070] The present invention will now be described merely by example with reference to the attached drawings.

[0071] FIG. 1 is a schematic diagram of a molding material according to one embodiment of the present invention.

[0072] FIG. 2 shows a schematic diagram of another molding material according to another embodiment of the present invention.

[0073] FIG. 1 illustrates a molding material (100) comprising a primary nonwoven fiber layer (102) and a secondary nonwoven fiber layer (104). The primary nonwoven fiber layer (102) includes a resin layer (106) that is exposed on its surface but extends across the primary nonwoven fiber layer (102) and at least the entire contact portion, and optionally extends partially or completely to the secondary nonwoven fiber layer (104). The primary and secondary nonwoven fiber layers (102, 104) are bonded by the adhesiveness of the resin layer (106).

[0074] In a specific embodiment, the primary nonwoven fabric layer (102) is 15 g / m 2 It is a nonwoven thermoplastic veil containing a mixture of polyamide and polyester materials having a weight of ; and the resin layer (106) is 65 g / m 2 Having a weight of 50 g / m², the secondary nonwoven fiber layer (104) is 50 g / m² 2 It is a glass fiber material fleece having a weight.

[0075] In a typical use, the molding material (100) is positioned in contact with the mold surface as the upper surface of the resin layer (106) in contact with the mold. An additional, at least partially resin-pre-impregnated reinforcing layer may be positioned on top of the molding material (100), i.e., in contact with the secondary nonwoven layer (104) to form a composite lay-up, which can then be subsequently cured to create a composite part. In an alternative use, the molding material (100) is positioned in contact with the tool surface as the upper surface of the resin layer (106) in contact with the tool. An additional unimpregnated (i.e., dry) reinforcing layer may be positioned on top of the molding material (100), i.e., in contact with the secondary nonwoven layer (104) to form a composite lay-up, which can then be subsequently injected with resin and cured to create a composite part.

[0076] FIG. 2 illustrates a molding material (200) comprising a primary nonwoven fiber layer (202) and a secondary nonwoven fiber layer (204). The primary nonwoven fiber layer (202) includes a resin layer (206) that is exposed on its surface and extends across the primary nonwoven fiber layer (202) and at least the entire contact portion, and optionally extends partially or completely to the secondary nonwoven fiber layer (204). A fiber reinforcement layer (208) is located on the opposite surface of the secondary nonwoven layer (204). The primary and secondary nonwoven fiber layers (202, 204) are bonded by the adhesiveness of the resin layer (206), and the secondary nonwoven fiber layer (204) and the reinforcement layer (208) are bonded by stitching. This leaves the reinforcement layer (208) unimpregnated with resin (dry).

[0077] In a specific embodiment, the resin composition contains a difunctional epoxy in combination with a urea-based curing agent; and the primary nonwoven fiber layer (202) is 15 g / m² 2 It is a nonwoven polyester having a weight of; and the resin layer (206) is 140 g / m 2 Having a weight of 50 g / m², the secondary nonwoven fiber layer (204) is 50 g / m² 2It is a glass fiber fleece with a weight of .

[0078] In a preferred embodiment, the reinforcing layer (208) is preferably in the form of two layers of unidirectional fibers that are combined to form a biaxial layer preferably having an orientation of + / - 45 degrees.

[0079] In a typical use, the molding material (200) is positioned in contact with the mold surface as the upper surface of the resin layer (206) in contact with the mold. An additional reinforcing layer is positioned on the upper surface of the molding material (200) to form a composite lay-up, which is then subsequently cured to create a composite part. In an alternative use, the molding material (200) is positioned in contact with the tool surface as the upper surface of the resin layer (206) in contact with the tool. An additional non-impregnated (i.e., dry) reinforcing layer is positioned on the upper surface of the molding material (200), i.e., in contact with the secondary nonwoven layer (204), to form a composite lay-up, which is then subsequently injected with resin and cured to create a composite part.

[0080] Accordingly, a molding material is provided that can be used in combination with a pre-impregnated fiber reinforcement (prepreg) layer having a resin content in the range of 30% to 45% by weight based on the weight of the prepreg, and can also be used to form a laminate in an injection system in combination with an unimpregnated fiber reinforcement layer.

[0081] Examples

[0082] Example 1

[0083] A resin composition (Composition 1) was formulated from the following:

[0084] 72.9 g Kukdo KFR136SL, semi-solid bisphenol A diglycidyl ether epoxy resin (manufactured by Kukdo Chemical Company Limited (Seoul, South Korea);

[0085] 18.2 g Epikote ®828 (Liquid bisphenol A diglycidyl ether epoxy resin manufactured by Hexion Inc. (Columbus, Ohio, USA);

[0086] 2.9 g Dyhard ® UR500 (a diactive latent urone accelerator in powder form manufactured by Alzchem Group AG (Trostberg, Germany).

[0087] The ingredients were thoroughly mixed at a temperature of 50 to 60°C until the consistency of the mixture became uniform.

[0088] The molding material was configured to have the following composition:

[0089] (1) Evalith ® S 5030 layer (50 g / m² manufactured by Johns Manville (Denver, Colorado, USA)) 2 Glass fiber fleece having an area weight;

[0090] (2) 15 g / m 2 A lightweight, fully synthetic nonwoven fiber bale layer comprising a blend of polyester and polyamide fibers having an area weight of (manufactured by Technical Fibre Products Limited (Burnside Mills, Kendall, Cumbria, UK); and

[0091] (3) 65 g / m 2 One layer of resin composition.

[0092] The assembled layers were integrated by passing them through an S-lap roller system heated to 80°C to form a molding material corresponding to the molding material (100) shown in FIG. 1.

[0093] Zyvax molding material (100) ®A composite tool treated with Watershield™ (a silicone-free water-soluble mold release agent manufactured by Freeman Manufacturing and Supply Company (Avon, Ohio, USA), and subsequently three layers of BB1000 fabric (1000 g / m² manufactured by Hexcel Reinforcements UK Limited (Naborough, Leicestershire, UK)). 2 Biaxial non-crimped glass fabric) and 1-layer Bleeder Lease B (62 g / m² from Airtech Europe Sarl (Differdange, Luxembourg) 2 A composite part was created by placing it on a silicone-treated nylon fabric, injecting Hexion RIM R135 / RIM H 137 (a combination of liquid epoxy resin and curing agent from Hexion Inc. (Columbus, Ohio, USA)) and curing it at 80°C for 6 hours under a pressure of 1 bar.

[0094] Upon cooling, the hardened molded part was removed for inspection and further testing.

[0095] Example 2

[0096] A resin composition (Composition 2) with the same components in equal amounts as Composition 1, but containing 6 g of Aerosil ® It was formulated by adding R202 (a hydrophobic fumed silica rheology modifier manufactured by Evonik Resource Efficiency GmbH (Hanau-Wolfgang, Germany).

[0097] The ingredients were thoroughly mixed at a temperature of 50 to 60°C until the consistency of the mixture became uniform.

[0098] The molding material was configured to have the following composition:

[0099] (1) LBB1200 fabric layer (1250 g / m² manufactured by Hexcel Reinforcements UK Limited (Naborough, Leicestershire, UK)2 Triaxial non-crimped glass fabric);

[0100] (2) Evalith ® S 5030 layer (50 g / m² manufactured by Johns Manville (Denver, Colorado, USA)) 2 Glass fiber fleece having an area weight;

[0101] (3) 15 g / m 2 A lightweight, fully synthetic nonwoven fiber bale layer comprising a blend of polyester and polyamide fibers having an area weight of (manufactured by Technical Fibre Products Limited (Burnside Mills, Kendall, Cumbria, UK); and

[0102] (4) 140 g / m 2 Two layers of resin composition.

[0103] The assembled layer was integrated by passing it through an S-lap roller system heated to 80°C to form a molding material corresponding to the molding material (200) shown in FIG. 2.

[0104] Molding material 1 Zyvax ® A composite tool treated with Watershield™ (a silicone-free water-soluble mold release agent manufactured by Freeman Manufacturing and Supply Company (Avon, Ohio, USA), and subsequently a three-layer BB1000 fabric (1000 g / m² manufactured by Hexcel Reinforcements UK Limited (Naborough, Leicestershire, UK)). 2 Biaxial non-crimped glass fabric) and 1 layer of Bleeder Lease B (62 g / m² from Airtech Europe Sarl (Differdange, Luxembourg) 2A composite part was created by placing it on a silicone-treated nylon fabric, injecting Hexion RIM R135 / RIM H 137 (a combination of liquid epoxy resin and curing agent from Hexion Inc. (Columbus, Ohio, USA)) and curing it at 80°C for 6 hours under a pressure of 1 bar.

[0105] Upon cooling, the hardened molded part was removed for inspection and further testing.

[0106] Example 3

[0107] A molding material having the following composition was formed using resin composition 2:

[0108] (1) 400 g / m 2 Two layers of resin composition;

[0109] (2) LBB1200 fabric layer (1250 g / m²) 2 Triaxial non-crimped glass fabric (manufactured by Hexcel Reinforcements UK Limited (Naborough, Leicestershire, UK));

[0110] (3) Evalith ® S 5030 layer (50 g / m² manufactured by Johns Manville (Denver, Colorado, USA)) 2 Glass fiber fleece having an area weight;

[0111] (4) 15 g / m 2 A lightweight, fully synthetic nonwoven fiber bale layer comprising a blend of polyester and polyamide fibers having an area weight of (manufactured by Technical Fibre Products Limited (Burnside Mills, Kendall, Cumbria, UK); and

[0112] (5) 400 g / m 2 Two layers of resin composition.

[0113] The assembled layer was integrated by passing it through an S-lap roller system heated to 80°C to form a molding material corresponding to the molding material (200) shown in FIG. 2.

[0114] The molding material (200) is formed by the resin composition layer (5) adjacent to the surface of the mold and Zyvax ® It was applied to a composite tool treated with Watershield™ (a silicone-free water-soluble mold release agent manufactured by Freeman Manufacturing and Supply Company (Avon, Ohio, USA). Two layers of HexPly ® 79 (prepreg manufactured by Hexcel GmbH (Neumarkt, Germany)) was placed on top of the molding material in the mold, that is, next to the resin layer (1); and the assembly was cured under vacuum at 80°C and 1 bar pressure for 6 hours. Upon cooling, the cured molded part was removed for inspection and further testing.

Claims

Claim 1 As a molding material, a) a primary nonwoven fiber layer, wherein the primary nonwoven fiber layer has an upper surface and a lower surface, and the primary nonwoven fiber layer comprises a polyester, aliphatic, or semi-aromatic polyamide fiber material having an area weight of 10 to 40 g / m², and the primary nonwoven fiber layer has an openness of 1 to 10% and an average open area of ​​75 to 350 micron², and the primary nonwoven fiber layer is completely saturated with a resin; b) a secondary nonwoven fiber layer, wherein the secondary nonwoven fiber layer has an upper surface and a lower surface, and the secondary nonwoven fiber layer comprises a glass fiber material, a polyolefin polymer material, or a combination of said materials, and has an area weight of 30 to 60 g / m²; c) a fiber reinforcing layer, wherein the fiber reinforcing layer has an upper surface and a lower surface; The lower surface of the fiber reinforcing layer is stitched to the upper surface of the secondary fiber layer, thereby leaving the fiber reinforcing layer in a state not substantially impregnated by resin; the reinforcing layer comprises at least two layers of unidirectional fibers, each unidirectional fiber layer arranged in a different direction; and the layers of the reinforcing layer are stitched together, wherein the fiber reinforcing layer; and d) a resin layer, wherein the resin layer comprises at least one resin component, at least one curing agent, and at least one silica filler; wherein the resin layer is bonded to the lower surface of the primary nonwoven fiber layer and the lower surface of the secondary nonwoven fiber layer is bonded to the upper surface of the primary nonwoven fiber layer; wherein the resin layer at least partially impregnates the primary nonwoven fiber layer and partially impregnates the secondary nonwoven fiber layer;A molding material comprising a resin layer comprising 25 to 50 weight percent of resin, wherein the resin layer bonds the secondary nonwoven fiber layer to the upper surface of the primary nonwoven fiber layer and the resin layer is exposed on the lower surface of the primary nonwoven layer, thereby providing excellent surface quality that, upon curing, is substantially pinhole-free and substantially print-through-free. Claim 2 A molding material according to claim 1, wherein the fibers of the layers of the unidirectional fibers of the reinforcing layer are 68 to 2400 tex. Claim 3 A molding material according to paragraph 2, wherein the primary nonwoven fiber layer has an air permeability of about 2,300 L / m² / s at an applied pressure of 200 Pa when measured according to ASTM D737-18. Claim 4 A method for manufacturing a laminate structure, comprising the steps of: placing a molding material according to claim 1 on the surface of a tool or mold by bringing a resin layer exposed on the lower surface of a primary nonwoven fiber layer into contact with the surface of the tool or the mold; forming a stack by applying one or more layers of a resin-free (dry) fiber reinforcement to the opposite surface of the molding material; injecting an injection resin into the stack; and curing the injected stack. Claim 5 A method according to claim 4, wherein at least one of the pre-impregnated fiber reinforcement (prepreg) layers is included in the stack before resin injection. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete

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