Bumper manufacturing process capable of achieving vehicle body color effect without spraying

Abstract

The invention discloses a bumper manufacturing process capable of realizing a vehicle body color effect without spraying, which comprises the following steps: injecting bumper body resin into a first cavity of a double-color injection mold, and performing injection molding to form a bumper body; carrying out surface energy treatment by using an online surface energy treatment system; a closed space formed by the bumper body and the second cavity is vacuumized; the closed space is filled with polyurethane resin, and the polyurethane resin is cured and cooled to form a transparent solid coating; and the pouring gate and the flash well are cut off, and a bumper product with the automobile body color decoration effect is obtained. Effect pigment and toner are added into bumper body resin or polyurethane resin, so that the bumper with the automobile body color effect is manufactured without spraying. According to the method, a high-pollution and high-energy-consumption paint spraying process needed by a conventional bumper manufacturing technology is avoided, the method is environmentally friendly, energy consumption of bumper manufacturing and influences on the natural environment are reduced, manual operation is reduced, and the strict test requirements of automobile exterior trimming are met.

Description

Technical Field

[0001] The invention relates to the field of automobile bumper manufacturing, and more specifically to a bumper manufacturing process for achieving a vehicle body color effect without spraying. Background Art

[0002] With the development of society, mankind has been pushed into a period of transition from the era of industrial civilization to the era of ecological civilization. Vigorously advocating a low-carbon economy and building an ecological civilization have become the main themes of the times. Conventional bumper manufacturing technology involves injection molding, water washing, flame treatment, spraying (primer + color paint + topcoat), baking and other processes. The existing technology usually sprays primer, color paint and varnish after the bumper body is injection molded. The primer layer increases the adhesion of the color paint layer and the varnish layer to the bumper body. Among them, the washing and spraying processes will produce wastewater, waste gas and waste residue, which will have a great impact on the natural environment. The baking process, as a high-energy consumption process, is the main source of energy consumption in the bumper production process. As an environmentally friendly technology, spray-free body-colored bumpers will greatly reduce the energy consumption of bumper manufacturing and the impact on the natural environment.

[0003] However, existing spray-free surface decoration technologies cannot achieve body color decoration effects, or require a lot of manual work, or cannot meet the stringent testing requirements for automotive exteriors. Summary of the invention

[0004] The purpose of the present invention is to provide a bumper manufacturing process that can achieve body color effects without spraying, thereby solving the problems in the prior art that spray-free surface decoration technology cannot achieve body color decoration effects, or requires a lot of manual work, or cannot meet the strict testing requirements for automobile exteriors.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] A bumper manufacturing process for achieving a vehicle body color effect without spraying is provided, comprising the following steps: S1: providing a two-color injection molding machine system equipped with a two-color injection mold, wherein the two-color injection mold comprises a first cavity and a second cavity, injecting a bumper body resin into the first cavity, and forming the bumper body by injection molding; S2: performing surface energy treatment on the bumper body using an online surface energy treatment system; S3: rotating the core of the first cavity of the two-color injection mold to cooperate with the second cavity, and vacuumizing the closed space formed by the bumper body and the second cavity; S4: providing a polyurethane infusion system, The two liquid components of the polyurethane resin are fully mixed at the mixing gun head through two independent pipes of the polyurethane infusion system, filled into the closed space formed by the bumper body and the second cavity, fully reacted and completed solidification and cooling, and formed a transparent solid coating with uniform thickness; S5: mold opening, the bumper after the polyurethane resin infusion is separated from the two-color injection molding machine system, the gate and the overflow well are cut off, and the bumper product with the body color decorative effect is obtained; wherein, the body color effect without spraying on the bumper is achieved by adding effect pigments and color powder to the bumper body resin in step S1 or the polyurethane resin in step S4.

[0007] Preferably, the two liquid components of the polyurethane resin are isocyanate and polyol, and the vehicle body color effect is achieved by adding effect pigments and color powder to the polyol of the polyurethane resin in step S4.

[0008] It should be understood that effect pigments refer to powdery additives that can produce a glittering effect and are essential additives for achieving the body color decorative effect. By way of example and not limitation, commonly used effect pigments are small-particle aluminum powder, aluminum flakes, silver powder, pearl powder, mesh flakes, etc.

[0009] Preferably, the vehicle body color effect is switched by switching injection molding particles to which effect pigments and color powders are added, wherein the effect pigments are metal powders or pearlescent powders.

[0010] Preferably, the bumper body resin is a thermoplastic resin, including: PP+EPDM-T12, PP+EPDM-T15, PP+EPDM-T20 and the like.

[0011] Preferably, the bumper body resin and the polyurethane resin have similar shrinkage rates and linear expansion coefficients to prevent the polyurethane coating from delaminating or falling off in a hot and cold alternating use environment.

[0012] Preferably, the online surface energy treatment system is used to perform surface treatment on the outer surface of the bumper body by clamping a flame treatment tool head or a plasma treatment tool head through a six-axis robot to enhance the adhesion between the bumper body resin and the polyurethane resin.

[0013] Preferably, in step S2, after the bumper body is treated by the online surface energy treatment system, the surface reaches a dyne value of 8 or more, so as to ensure that the subsequent polyurethane resin can infiltrate the surface of the bumper body and ensure that the adhesion between the polyurethane resin and the bumper body resin is greater than 200N / cm 2 , to avoid the phenomenon of decreased adhesion of surface thermoplastic resin and polyurethane coating. This can be achieved by controlling the flow rate of flame treatment gas and the distance between the flame nozzle and the product during flame treatment.

[0014] Preferably, the first cavity of the two-color injection mold is provided with a gate and an overflow well structure for pouring polyurethane resin into the second cavity, so that the polyurethane resin is evenly poured into the surface of the bumper body to form a transparent coating with uniform thickness.

[0015] Preferably, the second cavity is connected with the gate and the overflow well, the polyurethane thickness on the product surface is uniformly 0.3-0.7 mm, and the polyurethane thickness at the connection position between the gate and the overflow well and the second cavity is reduced to 0.2-0.4 mm to ensure that internal pressure can be generated during the polyurethane infusion process to avoid bubbles and shrinkage in the polyurethane coating.

[0016] Preferably, a vacuum system is provided at the end of the overflow well to reduce the generation of bubbles in the polyurethane coating.

[0017] Preferably, in step S3, the closed space formed by the bumper body and the second cavity is evacuated to make the vacuum pressure of the closed space less than -0.06Mpa, and after the vacuuming action is completed, a signal is transmitted to the polyurethane injection system.

[0018] In step S4, the two liquid components of the polyurethane resin, isocyanate and polyol, are prepared to be filled into the space of uniform thickness formed by the bumper body and the second cavity through a polyurethane injection system arranged on the second cavity side.

[0019] In step S5, the car body color bumper separated from the injection molding machine system is subjected to the removal of the bumper body resin gate and the polyurethane injection gate and the overflow well. The gate and the overflow well can be removed by a milling device, an ultrasonic removal device, or a hot cutting device. The present invention preferably uses an ultrasonic removal device to remove the gate and the overflow well. The product with the gate and the overflow well is a finished bumper with a car body color decorative effect.

[0020] It should be understood that the present invention is not limited to two-color injection molds, and can also use insert injection molds. The main purpose of protecting is such a bumper manufacturing process that achieves body color effects without spraying.

[0021] As described in the background technology of the present invention, the existing bumper manufacturing technology is achieved through injection molding + spraying. The body color spraying usually has three layers of paint, including primer, color paint and varnish, among which the primer is used to increase the adhesion between the paint and the bumper body, the color paint is used to achieve the body color effect, and the surface varnish is used to protect the body color paint. However, the washing and spraying processes involved will generate a large amount of wastewater, waste gas and waste residue, which will have a great impact on the natural environment and will also consume a lot of energy.

[0022] Precisely in order to solve these problems existing in the prior art, the present invention provides a bumper manufacturing process for achieving body color effects without spraying, including two-color injection molding technology and polyurethane in-mold infusion technology, by completing the injection molding of thermoplastic resin with added effect pigments and color powder in the first cavity of the two-color injection mold, or completing the injection molding of polyurethane resin with added effect pigments and color powder in the second cavity of the two-color injection mold. The bumper body prepared by this process step has the effect pigment effect and color of a conventional bumper, and at the same time eliminates the high-pollution and high-energy consumption painting process.

[0023] The bumper manufacturing process for achieving a body color effect without spraying provided by the present invention is improved mainly relative to the prior art in that: 1) the bumper body resin injection molding with effect pigments and color powder added is completed in the first cavity through step S1, or the polyurethane resin injection molding with effect pigments and color powder added is completed in the second cavity through step S4 to achieve the body color effect; 2) the surface energy treatment of the bumper body is performed using an online surface energy treatment system through step S2 to ensure the adhesion of the subsequent polyurethane coating to the bumper body. If step S2 is omitted, the polyurethane coating has no adhesion to the bumper body made of polypropylene material; 3) step S3 forms a vacuum environment in the second cavity to reduce the occurrence of bubbles in the polyurethane coating; 4) step S4 forms a polyurethane protective coating to meet the stringent test requirements for automotive exterior parts.

[0024] The key invention point of the present invention is that by adding effect pigments and color powders to the masterbatch of conventional bumper particles (semi-transparent white or white) or toners in two liquid components of polyurethane resin, the manufacturing of bumpers with body color effects can be achieved. Most importantly, the present invention realizes the spray-free manufacturing of bumpers with body color effects for the first time, avoiding the spraying process in the existing bumper manufacturing process.

[0025] The beneficial effects of the present invention compared with the prior art are as follows:

[0026] 1) The present invention realizes the spray-free manufacturing of the bumper with the vehicle body color effect, and the surface decoration of the bumper body is completed in the mold. After the product is taken out from the mold and the injection molding gate and the polyurethane injection gate are removed, the bumper is a finished product, and there is no need for multiple paint spraying (including water washing / primer spraying / color paint spraying / topcoat spraying / baking and other processes) required by the conventional bumper manufacturing process;

[0027] 2) After the bumper body is injection molded in the first cavity, the surface of the thermoplastic resin bumper body needs to be treated to increase the adhesion between the thermoplastic resin and the transparent polyurethane;

[0028] 3) The present invention does not require the use of solvents used in the spraying process, does not generate waste liquid / waste residue from paint spraying, does not require a water washing process to avoid pollution of water resources, and as a manufacturing process with extremely short processes, the present invention greatly reduces the energy consumption of bumper manufacturing, does not generate waste water / waste liquid / waste gas / waste residue, and is an environmentally friendly bumper manufacturing technology;

[0029] 4) The bumper manufactured by the present invention has a thickness of 2.3 to 4.2 mm, wherein the bumper body resin thickness is 2.0 to 3.5 mm, and the polyurethane coating thickness is 0.3 to 0.7 mm;

[0030] 5) The effect pigment used in the present invention may be a metal powder or pearlescent powder or other effect pigments, and the effect pigment and color powder are directly added to the injection molded particles of the bumper body or directly added to the polyurethane resin;

[0031] 6) The thermoplastic resin particles used in the present invention have no significant difference in manufacturing process and material properties from the resin particles used in conventional bumper manufacturing technology, and will not significantly increase the material cost of injection molding particles, nor will it cause additional impact on the environment.

[0032] In summary, according to the present invention, a bumper manufacturing process for achieving body color effect without spraying can achieve body color decorative effect after completing the injection molding of the bumper body and the infusion of polyurethane resin in a two-color injection molding machine. It does not require the high-pollution and high-energy consumption painting process required by conventional bumper manufacturing technology. It is the first time that the bumper with body color effect can be manufactured without spraying. It not only has the advantage of being environmentally friendly, greatly reducing the energy consumption of bumper manufacturing and the impact on the natural environment, but also reduces manual labor and meets the strict testing requirements for automotive exteriors. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The schematic diagram of the process principle of the bumper manufacturing process for achieving the vehicle body color effect without spraying of the present invention shows a two-color injection molding machine system and a polyurethane injection system;

[0034] Figure 2is a schematic diagram of step S1 of the method of the present invention, showing the injection molding of a body-colored bumper body in the first cavity of a two-color injection mold;

[0035] Figure 3 is a schematic diagram of step S2 of the method of the present invention, showing the use of an online surface energy treatment system to flame treat or plasma treat the surface of a vehicle body color bumper body;

[0036] Figure 4 is a schematic diagram of step S3 of the method of the present invention, showing that after the flame treatment of the body-colored bumper body is completed, the core of the first cavity is rotated and matched with the second cavity to perform vacuuming;

[0037] Figure 5 is a schematic diagram of step S4 of the method of the present invention, showing that the bumper body is subjected to polyurethane coating injection in the second cavity, while the first cavity is subjected to the next cycle of bumper body injection molding;

[0038] Figure 6 is a schematic diagram of step S5 of the method of the present invention, showing the structure of the gate and overflow well on the double-color injection mold;

[0039] The meanings of the reference numerals are as follows:

[0040] 1: first injection unit; 2: second injection unit; 3: first cavity; 4: second cavity; 5: rotating disk; 6: thermoplastic resin; 7: bumper body; 8: tool head; 9: clamping mechanism of two-color injection molding machine; 10: movable plate of two-color injection molding machine; 11: Green column; 12: fixed plate of two-color injection molding machine; 13: isocyanate storage tank; 14: polyol storage tank; 15: polyurethane resin infusion gun head; 16: polyurethane resin infusion port; 17: isocyanate; 18: polyol; 19: polyurethane resin coating; 20: gate; 21: overflow well; 22: connecting position between gate and second cavity; 23: connecting position between overflow well and second cavity; 24: vacuum system; 100: two-color injection molding machine system; 200: polyurethane infusion system; 300: surface energy treatment system. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional operations in the art, or according to the experimental methods recommended by the instrument and equipment manufacturers. The reagents and materials used in the examples can be obtained from commercial sources unless otherwise specified.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0043] Example 1

[0044] According to a first preferred embodiment of the present invention, a bumper manufacturing process for achieving a body color effect without spraying is provided, and the devices used mainly include a two-color injection molding machine system 100, a polyurethane injection system 200, and a surface energy treatment system 300. Figure 1 The main figures show a two-color injection molding system 100 and a polyurethane injection system 200, while a surface treatment system 300 is shown in FIG. Figure 3 Next, we will combine Figure 1-Figure 6 The manufacturing process of the bumper that achieves the body color effect without spraying is described in detail.

[0045] Step S1: Combination Figure 1 , Figure 2 As shown, the bumper body is injected into the first cavity of the two-color injection molding machine system 100 equipped with the two-color injection mold. Specifically, the two-color injection mold includes: a first injection unit 1, a second injection unit 2, a first cavity 3, a second cavity 4, and a rotating disk 5. The first injection unit 1 is used for injection molding of the bumper body, and the second injection unit 2 is used for injection molding of the polyurethane coating. In this step, the bumper body 7 is injected by injecting a thermoplastic resin 6 added with color powder and effect pigments into the first cavity 3;

[0046] Step S2: Combination Figure 1 , Figure 3As shown, the two-color injection molding machine system opens the mold, and then the online surface energy treatment system 300 is used to perform surface energy treatment on the bumper body 7. It should be understood that the surface energy treatment includes surface flame treatment, plasma treatment, etc. Specifically, when the clamping mechanism 9 of the two-color injection molding machine is opened, the movable plate 10 of the two-color injection molding machine moves along the Green column 11 relative to the fixed plate 12 of the two-color injection molding machine to realize mold opening, and the tool head 8 of the online surface energy treatment system 300 performs surface energy treatment on the bumper body 7 prepared in step S1. After the bumper body 7 is treated with the online surface energy treatment system, the surface reaches a dyne value of more than 8, ensuring that the subsequent polyurethane resin can infiltrate the surface of the bumper body 7, and ensuring that the adhesion between the polyurethane resin and the bumper body resin is greater than 200N / cm 2 , to avoid the phenomenon of decreased adhesion of surface thermoplastic resin and polyurethane coating.

[0047] Step S3: Combination Figure 1 , Figure 4 As shown, the core of the first cavity 3 of the two-color injection mold is rotated by the rotating disk 5 to cooperate with the second cavity 4, and then the closed space formed by the bumper body 7 and the second cavity 4 is evacuated to make the vacuum pressure of the closed space <-0.06Mpa, and the vacuuming completion signal is transmitted to the polyurethane infusion system 200.

[0048] Step S4: Combination Figure 1 , Figure 5 As shown, the polyurethane infusion system 200, that is, the second injection unit 2 mentioned above, is used for injection molding of the polyurethane coating. The polyurethane infusion system 200 includes: an isocyanate storage tank 13, a polyol storage tank 14, a polyurethane resin infusion gun head 15, and a polyurethane resin infusion port 16. First, the isocyanate 17 and the polyol 18 are fully mixed in the polyurethane resin infusion gun head 15 through two independent pipes of the polyurethane infusion system, and then filled into the closed space formed by the bumper body 7 and the second cavity 4 through the polyurethane resin infusion port 16. The two liquid components fully react and complete solidification and cooling, and a transparent solid coating with uniform thickness is formed on the surface of the bumper body 7, that is, the polyurethane resin coating 19.

[0049] Step S5: Open the mold, separate the bumper from the two-color injection molding machine system, remove the gate and overflow well, and obtain a bumper product with a body color decorative effect. Figure 1 , Figure 6As shown, the first cavity 3 of the two-color injection mold is provided with a gate 20 and an overflow well 21 structure for the second cavity 4 to pour the polyurethane resin, so that the polyurethane resin is evenly poured into the surface of the bumper body 7 to form a polyurethane resin coating 19 with uniform thickness. According to this preferred embodiment, the second cavity 4 is connected with the gate 20 and the overflow well 21, and the polyurethane thickness formed on the surface of the product is uniformly 0.3-0.7 mm. The connection position 22 between the gate 20 and the second cavity 4 is designed so that the polyurethane thickness here is reduced to 0.2-0.4 mm, and the connection position 23 between the overflow well 21 and the second cavity 4 is also designed so that the polyurethane thickness here is reduced to 0.2-0.4 mm. According to the present invention, it is ensured that internal pressure can be generated during the polyurethane pouring process to avoid bubbles and shrinkage of the polyurethane coating. It is also preferred that a vacuum system 24 is provided at the end of the overflow well 21 to reduce bubbles in the polyurethane coating.

[0050] Example 2

[0051] According to a second preferred embodiment of the present invention, a process for manufacturing a bumper that can achieve a body color effect without spraying is provided. The only difference between this process and Example 1 is that, instead of adding effect pigments and toner to the bumper body resin in step S1, effect pigments and toner are added to two liquid components of the polyurethane resin in step S4 to achieve the body color effect. Since this process is substantially the same as Example 1, it will not be described in detail here.

[0052] According to a preferred embodiment of the present invention, the two liquid components of the polyurethane resin are isocyanate and polyol, and the vehicle body color effect is achieved by adding effect pigments and color powder to the polyol of the polyurethane resin in step S4.

[0053] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A process for manufacturing a bumper that can achieve a body color effect without spraying, characterized in that: The following steps are involved: S1: providing a two-color injection molding machine system equipped with a two-color injection mold, wherein the two-color injection mold includes a first cavity and a second cavity, injecting a bumper body resin into the first cavity, and forming a bumper body by injection molding; S2: performing surface energy treatment on the bumper body using an online surface energy treatment system; S3: the core of the first cavity of the two-color injection mold rotates to cooperate with the second cavity to close the mold, and the closed space formed by the bumper body and the second cavity is vacuumed; S4: Provide a polyurethane infusion system, fully mix the two liquid components of the polyurethane resin in the mixing gun head through two independent pipes of the polyurethane infusion system, fill them into the closed space formed by the bumper body and the second cavity, fully react and complete solidification and cooling, and form a transparent solid coating with uniform thickness; S5: Open the mold, separate the bumper that has been injected with polyurethane resin from the two-color injection molding machine system, cut off the gate and overflow well, and obtain a bumper product with body color decoration effect; The bumper with the vehicle body color effect is manufactured without spraying by adding effect pigments and color powder to the bumper body resin in step S1 or the polyurethane resin in step S4.

2. The bumper manufacturing process according to claim 1, characterized in that: The two liquid components of the polyurethane resin are isocyanate and polyol, and the vehicle body color effect is achieved by adding effect pigments and color powder to the polyol of the polyurethane resin in step S4.

3. The bumper manufacturing process according to claim 1, characterized in that: The vehicle body color effect is switched by switching the added effect pigment and color powder, wherein the effect pigment is metal powder or pearlescent powder.

4. The bumper manufacturing process according to claim 1, characterized in that: The bumper body resin is a thermoplastic resin, including: PP+EPDM-T12, PP+EPDM-T15, or PP+EPDM-T20.

5. The bumper manufacturing process according to claim 1, characterized in that: The bumper body resin and the polyurethane resin have similar shrinkage rates and linear expansion coefficients to prevent the polyurethane coating from being delaminated or falling off in a hot and cold alternating use environment.

6. The bumper manufacturing process according to claim 1, characterized in that: The online surface energy treatment system performs surface treatment on the outer surface of the bumper body by clamping a flame treatment tool head or a plasma treatment tool head through a six-axis robot to enhance the adhesion between the polyurethane resin and the bumper body resin.

7. The bumper manufacturing process according to claim 1, characterized in that: In step S2, after the bumper body is treated by the online surface energy treatment system, the surface reaches a dyne value of 8 or more, and the phenomenon of decreased adhesion of the surface thermoplastic resin and polyurethane coating can be avoided.

8. The bumper manufacturing process according to claim 1, characterized in that: The first cavity of the two-color injection mold is provided with a gate and an overflow well structure for pouring polyurethane resin into the second cavity, so that the polyurethane resin is evenly poured into the surface of the bumper body to form a transparent coating with uniform thickness.

9. The bumper manufacturing process according to claim 8, characterized in that: The second cavity is connected to the gate and the overflow well. The polyurethane thickness on the surface of the product is uniform, between 0.3 and 0.7 mm. The polyurethane thickness at the connection position between the gate and the overflow well and the second cavity is reduced to 0.2 to 0.4 mm to ensure that internal pressure can be generated during the polyurethane infusion process to avoid bubbles and shrinkage in the polyurethane coating.

10. The bumper manufacturing process according to claim 8, characterized in that: A vacuum system is arranged at the end of the overflow well to reduce bubbles generated by the polyurethane coating.

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