Fabric capable of realizing three-dimensional structure for reinforcing structure of injection-molded parts and injection method

Abstract

The fabric provided by this invention for reinforcing injection molded parts and enabling three-dimensional structures is woven from interlaced warp and weft threads. Multiple mesh openings are evenly distributed across the fabric's width, with a fixed perimeter. When the fabric is pressed, the deformation of the mesh openings allows it to form a three-dimensional structure, achieving a close fit with injection molded parts with complex three-dimensional shapes. This avoids seams on the injection molded part that prevent load transfer via fiber strips and does not increase thickness. It can easily cover the edges of the injection molded part. After injection molding, the base plastic not only connects to the fabric surface but also penetrates the mesh openings, resulting in strong overall bonding and the ability to withstand loads in different directions, thus providing better reinforcement of the overall structure of the injection molded part. The injection molding method provided by this invention is simple and easy to operate, enabling the production of injection molded parts with better structural strength and complex three-dimensional shapes, thus expanding the applicability of injection molded parts.

Description

Technical Field

[0001] This invention belongs to the field of injection molding technology, specifically relating to a fabric for reinforcing the structure of injection molded parts, capable of realizing a three-dimensional structure, and an injection molding method thereof. Background Technology

[0002] Injection molded parts refer to a general term for various injection molded products produced by injection molding machines. They are mainly made of polyethylene, polypropylene, or other materials and have advantages such as high production efficiency, convenient mass production, good molding effect, and high freedom of shape design. They are widely used in automotive plastic parts such as fenders, bumper covers, dashboards, and airbag covers. However, these injection molded parts typically have thin walls and low overall strength. To improve structural strength, current technologies mostly use fabric inserts within the injection molded parts. Common inserts are high-strength, high-modulus fiber strips, such as fiberglass strips. However, these fiber strips have low elasticity and can only adapt to simple bending in a single direction. When encountering injection molded parts with complex shapes such as three-dimensional curved surfaces, bending a single fiber strip in a single direction cannot achieve good fit. Therefore, two perpendicular fiber strips are usually bent from two different directions to achieve fit, such as... Figure 1 As shown, this solution results in seams on the injection molded part where the load cannot be transferred through the fiber strips. At the point where the two fiber strips overlap, the thickness will also increase to a certain extent. At the edge of the injection molded part, areas without fiber strips are easily generated, thus affecting the overall structural reinforcement effect of the injection molded part.

[0003] Furthermore, these fiber tapes are generally planar structures. When they become inserts, the connection between the fiber tape and the base plastic of the injection molded part comes from the adhesive force between the surface of the fiber tape and the base plastic. When the injection molded part is subjected to a load in a direction other than this adhesive force, this connection force is difficult to play a role and can only be resisted by the strength of the base plastic itself. This can easily lead to phenomena such as fiber tape misalignment and base plastic tearing, and the ability to bear loads in different directions is weak. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fabric for reinforcing injection molded parts, capable of realizing a three-dimensional structure, and an injection molding method thereof.

[0005] To achieve the above objectives, the product in the technical solution of this invention is a fabric for reinforcing the structure of injection molded parts and capable of realizing a three-dimensional structure. It is woven from crisscrossing warp and weft threads, and multiple meshes are evenly distributed on the width of the fabric. The perimeter of the meshes is fixed. When the fabric is pressed, the deformation of the meshes can enable the fabric to form a three-dimensional structure, thereby achieving a fit with the injection molded part.

[0006] Preferably, the woven portion of the warp and weft threads is wrapped with an adhesive layer for fixing the perimeter of the mesh.

[0007] More preferably, the adhesive layer is formed by drying an adhesive containing a polyurethane dispersant.

[0008] More preferably, the adhesive penetrates into the warp and weft threads before drying.

[0009] More preferably, after drying, the weight of the adhesive layer on each square meter of the fabric is 30g ± 3g.

[0010] Preferably, the warp and weft threads are made of aramid fiber or polyester fiber.

[0011] Preferably, the warp and weft yarns include a warp yarn group for forming one side of the mesh and a weft yarn group for forming the adjacent side of the mesh. The warp yarn group includes two independent warp yarns that are intertwined with each other, and the weft yarn group includes one weft yarn that is in a straight state.

[0012] More preferably, the two warp threads of the warp group are twisted together at intervals, and each time they intersect, one of the weft threads is sandwiched in the middle.

[0013] More preferably, the density of the warp group is 40 / 10cm, and the density of the weft group is 35 / 10cm.

[0014] More preferably, the fabric is used to manufacture automotive plastic parts.

[0015] To achieve the above objectives, the method employed in this invention is an injection molding method, comprising the following steps:

[0016] A. The fabric body is woven with crisscrossing warp and weft threads to form a fabric body with multiple meshes evenly distributed across the width;

[0017] B. Immerse the fabric body in the adhesive;

[0018] C. After the glue has completely penetrated into the warp and weft threads, the fabric body is taken out and dried, so that the glue wrapped around the warp and weft threads and the warp and weft threads at the braided part can be cured to form an adhesive layer, and the fabric is obtained.

[0019] D. Press the fabric with a mold to cause the mesh of the fabric to deform with a constant perimeter, forming a three-dimensional structure;

[0020] E. The fabric with the three-dimensional structure is placed into an injection mold for injection molding, so that the base plastic wraps around the fabric and passes through the mesh to obtain an injection molded part.

[0021] Preferably, the materials of the warp and weft threads in step A include aramid fiber and polyester fiber, and the density of the warp and weft threads in step A is 40 / 10cm for warp and 35 / 10cm for weft.

[0022] Preferably, the adhesive in step B contains a polyurethane dispersant.

[0023] Preferably, before drying in step C, the process further includes blowing away the adhesive holding the mesh together with a hair dryer to clear the mesh.

[0024] Preferably, after drying in step C, the weight of the adhesive layer on each square meter of the fabric is 30g ± 3g.

[0025] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0026] The fabric provided by this invention for reinforcing injection molded parts and enabling three-dimensional structures is woven from interlaced warp and weft threads. Multiple mesh openings are evenly distributed across the fabric's width, with a fixed perimeter. When the fabric is pressed, the deformation of the mesh openings allows it to form a three-dimensional structure, achieving a close fit with injection molded parts with complex three-dimensional shapes. This avoids seams on the injection molded part that prevent load transfer via fiber strips and does not increase thickness. It can easily cover the edges of the injection molded part. After injection molding, the base plastic not only connects to the fabric surface but also penetrates the mesh openings, resulting in strong overall bonding and the ability to withstand loads in different directions, thus providing better reinforcement of the overall structure of the injection molded part. The injection molding method provided by this invention is simple and easy to operate, enabling the production of injection molded parts with better structural strength and complex three-dimensional shapes, thus expanding the applicability of injection molded parts. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an existing technology that uses glass fiber tape embedded in injection molded parts.

[0028] Figure 2 This is a schematic diagram of the structure of a preferred embodiment of the fabric in this invention.

[0029] Figure 3 yes Figure 2 The enlarged cross-sectional view along the AA direction only shows a single parallel group and a single meridian group.

[0030] Figure 4 yes Figure 1 A schematic diagram of the three-dimensional structure formed by the fabric.

[0031] Figure 5 yes Figure 1 A schematic diagram of fabric embedded in an injection molded part.

[0032] Among them: 10. Fabric; 11. Mesh; 21. Braided section; 22. Warp; 23. Weft; 30. Adhesive layer. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the invention can be more readily understood by those skilled in the art.

[0034] like Figures 2 to 5 As shown, the fabric 10 for reinforcing the injection molded part structure and capable of realizing a three-dimensional structure provided by the present invention is woven from crisscrossing warp and weft threads. The fabric 10 has multiple meshes 11 evenly distributed on its surface. The perimeter of the meshes 11 is fixed. Specifically, the woven portion 21 of the warp and weft threads and the warp and weft threads themselves are wrapped with an adhesive layer 30 for fixing the perimeter of the meshes 11. The adhesive layer 30 is made by drying an adhesive containing a polyurethane dispersant. Before drying, the adhesive also penetrates into the warp and weft threads. When the fabric 10 is pressed, it can form a three-dimensional structure by deforming the meshes 11 without changing their perimeter, thus achieving adhesion to the injection molded part.

[0035] The advantage of this design is that it avoids seams on the injection molded part that prevent the load from being transferred through the fiber strip, and it does not increase the thickness. It can easily cover the edges of the injection molded part. After injection molding, the base plastic not only connects to the fabric on the surface of the fabric, but also connects to the fabric through the mesh on the fabric. The overall connection force is strong and can withstand loads in different directions, resulting in a better strengthening effect on the overall structure of the injection molded part.

[0036] In this embodiment, the warp and weft yarns include a warp yarn group for forming one side of the mesh 11 and a weft yarn group for forming the adjacent side of the mesh 11. To ensure the stability of the mesh 11 in the insert 10, the warp yarn group further includes two independent and intertwined warp yarns 22, and the weft yarn group includes one straight weft yarn 23. The two warp yarns 22 of the warp yarn group are intertwined at intervals, and each time they cross, a weft yarn 23 is sandwiched in the middle (when crossing, the small gaps between the two warp yarns 22 and the weft yarn 23 of the warp yarn group are also filled with adhesive layer 30), so that in the weaving part of the warp and weft yarns, the two warp yarns 22 of the warp yarn group are located above and below the weft yarn 23, respectively. The warp yarns 22 and weft yarns 23 are preferably aramid fibers, high-strength polyester fibers, or carbon fibers, and other types of high-strength fibers can also be used. For the weaving of the fabric 10, different methods such as weaving and knitting can be used, as long as the same deformable mesh can be formed, which is not limited here.

[0037] In this embodiment, the fabric 10 is used to manufacture automotive plastic parts. Therefore, the deformation of the mesh 11 needs to have a certain degree of flexibility so that the thickness of the adhesive layer 30 cannot be too thick. Of course, in order to achieve the stability of the fixed perimeter of the mesh 11, the thickness of the adhesive layer 30 cannot be too thin. Preferably, after drying, the weight of the adhesive layer 30 on each square meter of fabric 10 is 30g ± 3g. At the same time, the density of the warp and weft groups on the fabric 10 will also affect the deformation of the mesh 11. Preferably, the density of the warp group is 40 / 10cm, and the density of the weft group is 35 / 10cm.

[0038] In this invention, due to the presence of the adhesive layer 30, the perimeter of each mesh 11 on the fabric 10 remains fixed, such as... Figure 2 As shown, the mesh 11 can be regarded as a rectangle with a fixed side length. Under the action of external force, it can undergo shearing motion and become a parallelogram. At this time, the spacing between the warp and weft groups will change. Through the deformation of multiple meshes to different degrees, the warp and weft threads can present a curved state, so that the entire fabric 10 can present a three-dimensional structure without wrinkles or with fewer wrinkles, so as to achieve the fit with the shape of the injection molded part.

[0039] The present invention also provides an injection molding method for manufacturing automotive plastic parts, comprising the following steps:

[0040] A. The fabric body is woven with crisscrossing warp and weft threads to form a fabric body with multiple meshes evenly distributed across the width;

[0041] B. Immerse the fabric itself in the adhesive;

[0042] C. After the glue has completely penetrated into the warp and weft threads, remove the fabric body and dry it to allow the glue wrapped around the warp and weft threads and the warp and weft weave parts to solidify and form an adhesive layer, thus obtaining the fabric.

[0043] D. By pressing the fabric with a mold, the mesh of the fabric undergoes deformation with a constant perimeter, forming a three-dimensional structure;

[0044] E. Place the fabric with a three-dimensional structure into an injection mold for injection molding, so that the base plastic wraps around the fabric and passes through the mesh to obtain an injection molded part.

[0045] The advantage of this setup is that it simplifies the injection molding process, makes it easier to operate, and enables the production of injection molded parts with better structural strength and complex three-dimensional shapes, thereby expanding the applicability of injection molded parts.

[0046] During step D, the mesh undergoes shearing motion and transforms into a parallelogram (deformation). At this time, the spacing between the warp and weft threads changes. Through the deformation of multiple meshes to different degrees, the warp and weft threads can present a curved state, allowing the entire fabric to present a three-dimensional structure without wrinkles or with fewer wrinkles, thus achieving a fit with the shape of the injection molded part.

[0047] Preferably, the materials of the warp and weft threads in step A include aramid fiber, polyester fiber, and carbon fiber, and the density of the warp and weft threads in step A is 40 / 10cm for warp and 35 / 10cm for weft.

[0048] Preferably, the adhesive in step B contains a polyurethane dispersant.

[0049] Preferably, before drying in step C, the process further includes blowing away the glue that is sticking to the mesh with a hair dryer to clear the mesh.

[0050] Preferably, after drying in step C, the weight of the adhesive layer on each square meter of fabric is 30g ± 3g.

[0051] The fabric and injection molding method provided by this invention can perfectly fit the shape of the injection molded part to be reinforced, making it easier to cover the entire surface of the injection molded part. This allows for reinforcement of every corner of the entire injection molded part. Furthermore, because there are no seams when the fabric covers the entire injection molded part, the reinforcement effect is better. In addition, the mesh structure in the fabric allows the base plastic to pass through during injection molding, so that the base plastic after injection molding can fully bond with the fabric, improving the reliability during use.

[0052] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An injection molding method, characterized in that, Includes the following steps: A. The fabric body is woven with crisscrossing warp and weft threads, with multiple meshes evenly distributed across the width. When the threads intersect, the two warp threads of the warp group are twisted together at intervals, and each time they intersect, a weft thread is sandwiched in the middle. B. Immerse the fabric body in the adhesive; C. After the glue has completely penetrated into the warp and weft threads, the fabric body is taken out, and the glue sticking to the mesh is blown off by a hair dryer to clear the mesh. After clearing, it is dried to solidify the glue wrapped around the warp and weft threads themselves, the woven part of the warp and weft threads, and the glue filling the small pores between the two warp threads and the weft threads of the warp group to form an adhesive layer, thus obtaining the fabric. D. Press the fabric with a mold to cause the mesh of the fabric to deform with a constant perimeter, forming a three-dimensional structure; E. The fabric with the three-dimensional structure is placed into an injection mold for injection molding, so that the base plastic wraps around the fabric and passes through the mesh to obtain an injection molded part.

2. The injection molding method according to claim 1, characterized in that: The materials of the warp and weft threads mentioned in step A include aramid fiber and polyester fiber, and the density of the warp and weft threads mentioned in step A is 40 / 10cm for warp and 35 / 10cm for weft.

3. The injection molding method according to claim 1, characterized in that: The adhesive in step B contains a polyurethane dispersant.

4. The injection molding method according to claim 1, characterized in that: After drying in step C, the weight of the adhesive layer on each square meter of the fabric is 30g ± 3g.

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