Flock-like plastic part and method for producing the same

Abstract

The present application relates to injection molding processing technical field, specifically to a kind of flocked plastic parts and preparation method thereof.A kind of preparation method of flocked plastic parts, in injection molding step, the melt of flocked material containing elastomer is injected using the sequential valve process of fast speed, slow speed, fast speed to obtain flocked plastic parts;The condition of slow speed is: speed is 5-30%, pressure is 0-40bar;The condition of fast speed is: speed is 50-100%, pressure is 60-100bar.The method is stretched, broken, quickly distributed in the surface of mould by the sequential valve process of fast-slow-fast, and the flocked plastic parts prepared have soft touch and the visual appearance effect of flocked.

Description

Technical Field

[0001] This invention relates to the field of injection molding technology, specifically to a flocked plastic part and its preparation method. Background Technology

[0002] As people's demands for natural comfort and low-carbon environmental protection in automobiles increase, the requirements for the appearance, feel, and biomimetic design of automotive interior components are also rising. Traditional components are mostly hard plastic parts produced by injection molding, but due to their high gloss and plastic feel, they give a cheap impression. To improve the feel, slush molding or IML processes are often used to coat the surface of hard plastic with PU or PVC. Alternatively, low-pressure injection molding or adhesive processes can be used to coat a plastic skeleton with non-woven fabric to enhance the texture. However, these processes are complex, demanding, and the introduction of adhesives is not environmentally friendly.

[0003] Currently, material manufacturers are successively developing polypropylene composite materials, hoping to produce automotive interiors through simple injection molding processes. However, none of them have explained the application effects of the materials. For example, adding a flocking-effect material to polypropylene can prepare a flocking-effect material, but through simple injection molding, the flocking-effect material is only partially applied to the surface of the plastic part, making it difficult to achieve a true flocking effect. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the existing imitation flocking preparation process cannot make the imitation flocking effect material be distributed in large quantities on the surface, thereby providing an imitation flocking plastic part and its preparation method to solve the above problem.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing a flocked plastic part, wherein in the injection molding step, the melt of the flocked material containing an elastomer is injected using a sequential valve process of high speed, slow speed, and high speed to obtain the flocked plastic part.

[0007] The conditions for the slow speed are: speed of 5-30% and pressure of 0-40 bar;

[0008] The conditions for the high speed are: speed of 50-100% and pressure of 60-100 bar.

[0009] Preferably, the distance L from the gate to the runner in the injection molding mold is 1.5-2.0 mm, and the relationship between the gate width W and the runner diameter D is: W × 2 mm = πD 2 / 6.

[0010] Preferably, the mold used in the injection molding process has a gate located at the center of its four sides;

[0011] And / or, the injection molding is performed using an injection molding machine with a maximum clamping force of 500-3000T;

[0012] And / or, the injection molding temperature is 200-215°C.

[0013] Preferably, the flocking-like material containing the elastomer is a composite of polypropylene, a flocking-like effect material, and an elastomer.

[0014] Preferably, the material used to create the flocking effect is at least one of fiber dots, short fibers, and wood powder;

[0015] And / or, the elastomer is ethylene propylene diene monomer (EPDM) rubber and / or polyethylene octene coelastomer (POE).

[0016] Preferably, the mass ratio of the polypropylene to the flocking effect material is 100:(5-30);

[0017] And / or, the mass ratio of the polypropylene to the elastomer is 100:(3-8);

[0018] And / or, the size of the elastomer is 100-300 μm.

[0019] Preferably, the process of obtaining the flocked material containing the elastomer is as follows: polypropylene is mixed with the flocked material and the elastomer, then added to an extruder to melt and extrude, and then subjected to water treatment, pelletizing, cooling and drying to obtain the final product.

[0020] Preferably, the melting temperature is 185-215°C.

[0021] Preferably, the extruder is a twin-screw extruder;

[0022] And / or, the screw speed of the extruder is 300 r / min;

[0023] And / or, the length-to-diameter ratio of the extruder is 40:1.

[0024] Preferably, the screw speed for injection molding is 450 r / min.

[0025] The present invention also provides a flocked plastic part, which is prepared by the above-described method for preparing flocked plastic parts.

[0026] Preferably, the flocked plastic part is a flocked column.

[0027] In this invention, the speed is the speed relative to when the injection molding machine control valve is 100% open.

[0028] The technical solution of this invention has the following advantages:

[0029] 1. A method for preparing a flocked-like plastic part, wherein in the injection molding step, the melt of the flocked-like material containing elastomers is injection molded using a sequential valve process of high speed, slow speed, and high speed to obtain the flocked-like plastic part; the conditions for the slow speed are: speed 5-30%, pressure 0-40 bar; the conditions for the high speed are: speed 50-100%, pressure 60-100 bar. This method, through the sequential valve process of high-low-high speed, causes the elastomer component in the melt of the flocked-like material to stretch, break, and rapidly distribute on the mold surface. Simultaneously, utilizing the driftwood principle, a large amount of flocked-like effect material is distributed on the surface layer. The resulting flocked-like plastic part possesses both a soft touch and the visual appearance of flocking, and can replace traditional textile-covered plastic parts. It not only meets basic performance requirements but also satisfies people's requirements for the appearance, feel, and biomimetic properties of automotive interior parts.

[0030] 2. In the preparation method of the flocked plastic part of the present invention, the mold gate is also designed. By designing the mold gate, this application can further distribute the elastomer and flocked effect material in large quantities on the surface, thereby further improving the soft touch of the plastic part and the visual appearance of the flocked effect.

[0031] 3. In the preparation method of the flocked plastic part of the present invention, the elastomer has a specific size, which can provide a soft feel while maintaining high rigidity. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the gate structure used in Embodiment 1 of the present invention;

[0034] Figure 2 This is a physical image of the flocked column prepared in Example 1 of the present invention. Detailed Implementation

[0035] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0036] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0037] Example 1

[0038] This embodiment provides a method for preparing a flocked plastic part, wherein the flocked plastic part is a flocked column, and includes the following steps:

[0039] 1) Obtaining the flocked material: Polypropylene, fiber dots, and ethylene propylene diene monomer (EPDM) are mixed evenly. The mass ratio of polypropylene to fiber dots is 100:5, the mass ratio of polypropylene to EPDM is 100:3, and the size of EPDM is 100μm. Then, the mixture is added to a twin-screw extruder, melted and extruded at 185℃. The screw speed during extrusion is 300r / min, and the length-to-diameter ratio of the twin-screw extruder is 40:1. The mixture is then subjected to water treatment, pelletizing, cooling, and drying to obtain the final product.

[0040] 2) Add the flocked material from step 1) to the injection molding machine, and use a sequential valve process of high speed, slow speed, high speed to inject it into the mold to obtain the flocked column. The actual flocked column is as follows: Figure 2 As shown; the injection molding uses an injection molding machine with a maximum clamping force of 500T, an injection temperature of 200℃, and a screw speed of 450r / min; the slow speed conditions are: speed 20% and pressure 30bar; the fast speed conditions are: speed 50% and pressure 60bar; the distance from the gate to the runner in the injection molding is 1.5mm, the gate width W is 6.6mm, the runner diameter D is 5mm, and the mold gate structure is as follows. Figure 1 As shown, gates are provided in the middle of all four sides of the mold.

[0041] Example 2

[0042] This embodiment provides a method for preparing a flocked plastic part, wherein the flocked plastic part is a flocked column, and includes the following steps:

[0043] 1) Obtaining the flocked material: Polypropylene is mixed with short fibers and polyethylene octene elastomer (POE). The mass ratio of polypropylene to short fibers is 100:30, the mass ratio of polypropylene to POE is 100:8, and the size of POE is 300μm. Then, it is added to a twin-screw extruder, melted and extruded at 200℃. The screw speed during extrusion is 300r / min, and the length-to-diameter ratio of the twin-screw extruder is 40:1. Then, it is subjected to water treatment, pelletizing, cooling and drying to obtain the material.

[0044] 2) Add the flocked material from step 1) into the injection molding machine, and use a sequential valve process of high speed, slow speed, and high speed to inject it into the mold to obtain flocked columns; wherein, the injection molding machine has a maximum clamping force of 3000T, an injection temperature of 200℃, and a screw speed of 450r / min; the slow speed conditions are: speed of 30% and pressure of 40bar; the high speed conditions are: speed of 80% and pressure of 80bar; the distance from the gate to the runner of the mold in the injection molding process is 1.8mm, the gate width W is 16.7mm, the runner diameter D is 8mm, and gates are set in the middle of the four sides of the mold.

[0045] Example 3

[0046] This embodiment provides a method for preparing a flocked plastic part, wherein the flocked plastic part is a flocked column, and includes the following steps:

[0047] 1) Obtaining the imitation flocking material: Polypropylene, wood flour, and ethylene propylene diene monomer (EPDM) are mixed evenly. The mass ratio of polypropylene to wood flour is 100:20, the mass ratio of polypropylene to EPDM is 100:5, and the size of EPDM is 100μm. Then, it is added to a twin-screw extruder, melted and extruded at 215℃. The screw speed during extrusion is 300r / min, and the length-to-diameter ratio of the twin-screw extruder is 40:1. Then, it is subjected to water treatment, pelleting, cooling, and drying to obtain the material.

[0048] 2) Add the flocked material from step 1) into the injection molding machine, and use a sequential valve process of high speed, slow speed, and high speed to inject it into the mold to obtain flocked columns; wherein, the injection molding machine has a maximum clamping force of 2800T, an injection temperature of 215℃, and a screw speed of 450r / min; the slow speed conditions are: speed of 5% and pressure of 0bar; the high speed conditions are: speed of 100% and pressure of 100bar; the distance from the gate to the runner of the mold in the injection molding process is 2.0mm, the gate width W is 16.7mm, the runner diameter D is 8mm, and gates are set in the middle of the four sides of the mold.

[0049] Example 4

[0050] The difference between this comparative example and Example 2 is that a conventional mold with two gates without special requirements was used to injection mold the imitation flocked column. The gate size of the mold is 25.2mm and the gate position is located in the middle. Other conditions are the same as in Example 2.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 2 is that the simulated flocked column is obtained by injection molding using a sequential valve process of slow speed, fast speed, and slow speed. Other conditions are the same as in Example 2.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 2 is that only slow injection molding was used to obtain the flocked column, while other conditions were the same as in Example 2.

[0055] Comparative Example 3

[0056] The difference between the comparative example and Example 2 is that only the rapid injection molding was used to obtain the flocked column, while other conditions were the same as in Example 2.

[0057] Test Example 1

[0058] The simulated flocked columns prepared in Examples 1-4 and Comparative Examples 1-3 were evaluated for appearance and tactile feel. The appearance evaluation method involved comparing the molded simulated flocked columns with fabric, with the appearance grades shown in Table 1. The tactile evaluation method involved using a 5mm diameter probe to contact the surface of the product, testing the indentation depth and diameter under 0N and 5N load conditions respectively; the larger the difference, the softer the feel. The results of the appearance and tactile evaluations are shown in Table 2.

[0059] Table 1

[0060] Appearance level 1 The fabric effect is obvious, and the difference cannot be distinguished by visual inspection. 2 The downy fibers are evenly distributed, without clusters or obvious differences in light and dark. 3 The fluff is relatively evenly distributed, without aggregation, and there are slight differences in light and dark areas ≤2. 4 The fluff is basically evenly distributed, without aggregation, and the difference in light and dark areas is ≥3. 5 The downy hairs are basically evenly distributed and clustered, with obvious light and dark differences ≥3.

[0061] Table 2

[0062]

[0063]

[0064] According to the evaluation results in Table 2, compared with the flocked columns of Comparative Examples 1-3, the flocked columns prepared by the fast-slow-fast sequential valve process in Examples 1-4 of this invention have both excellent soft touch and flocked visual appearance. In Examples 1-3, the distance from the gate to the runner of the mold used in injection molding is 1.5-2.0 mm, and the relationship between the gate width W and the runner diameter D is: W × 2 mm = πD 2 / 6, while Example 4 uses a conventional mold with two gates and no special requirements for injection molding. The tactile evaluation results of the flocked column of Examples 1-3 are better than those of the flocked column of Example 4.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a flocked-look plastic part, characterized in that, In the injection molding process, the melt of the flocked material containing elastomer is injected using a sequential valve process of high speed, slow speed, and high speed to obtain flocked plastic parts. The conditions for the slow speed are: speed of 5-30% and pressure of 0-40 bar; The conditions for the high speed are: speed of 50-100% and pressure of 60-100 bar; The distance L from the gate to the runner in the injection molding mold is 1.5-2.0 mm. The relationship between the gate width W and the runner diameter D is: W × 2 mm = πD 2 / 6; The flocking-like material containing the elastomer is a composite of polypropylene, a flocking-like effect material, and an elastomer; the flocking-like effect material is at least one of fiber particles and wood flour; the elastomer is EPDM rubber; the mass ratio of polypropylene to flocking-like effect material is 100:(5-30); the mass ratio of polypropylene to elastomer is 100:(3-8); and the size of the elastomer is 100-300 μm.

2. The preparation method according to claim 1, characterized in that, The injection mold used in the above injection molding process has gates located at the center of the four sides; And / or, the injection molding is performed using an injection molding machine with a maximum clamping force of 500-3000 T; And / or, the injection molding temperature is 200-215°C.

3. The preparation method according to claim 1 or 2, characterized in that, The process of obtaining the flocked material containing the elastomer is as follows: polypropylene is mixed with the flocked material and the elastomer, then added to an extruder to melt and extrude, and then subjected to water treatment, pelletizing, cooling and drying to obtain the final product.

4. The preparation method according to claim 3, characterized in that, The melting temperature is 185-215℃.

5. A flocked plastic part, characterized in that, It is prepared by the method for preparing flocked plastic parts according to any one of claims 1-4.

6. The flocked plastic part according to claim 5, characterized in that, The imitation flocked plastic part is an imitation flocked column.

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