CROSS REFERRENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to Chinese patent application No. 201210526383.7, filed on December 7, 2012, and entitled "System and Method of Injection Molding, Vehicle Glass Encapsulation and Vehicle Window", the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present disclosure generally relates to glass technology field, and more particularly, to a system and method of injection molding for forming a vehicle glass encapsulation, a vehicle glass encapsulation by the method of injection molding, and a vehicle window having the vehicle glass encapsulation.

BACKGROUND

[0003] Glass encapsulation can improve sealing performance, noise reduction capability and glass safety, and can make glass more aesthetic in appearance.

[0004] Chinese patent application No. CN102180081A discloses a rear quarter window. FIG. 1 schematically illustrates the rear quarter window according to the application. The rear quarter window includes a glass 11 and a glass encapsulation 12 formed on the periphery of the glass 11. The glass encapsulation 12 includes a glue-coating surface 121, a lip 122 and a glue-holding groove 123. The glue-holding groove 123 is formed on the glue-coating surface 121 and is used for glue coating. The glue-holding groove 123 can prevent the glass glue from flowing transversely which may result in a glue leakage. The lip 122 takes a lamellar shape and can deform under pressure. The glass encapsulation 12 is formed via an injection molding process.

[0005] The injection molding process is described as follows. A raw material is plasticized to form a solution which is then injected into a mould cavity. The solution cools and solidifies in the mould cavity to form an injection-molded part having a shape matching the shape of the mould cavity.

[0006] However, when forming a glass encapsulation in an injection molding process, the solution in the mould cavity may shrink during cooling, which makes the size of the glass encapsulation less than its design. As a result, the glass encapsulation can not match well with components of a vehicle window. For example, when assembling the vehicle window, a crack may occur due to a dimension mismatch between a glass encapsulation and a trimming.

[0007] To avoid the shrinkage, injection pressure is increased. However, glass tends to crack if injection pressure is increased, which results in a decrease of yield.

SUMMARY

[0008] Embodiments of the present disclosure provide an injection molding system in order to avoid natural shrinking caused by cooling in the process of injection molding.

[0009] In one embodiment, an injection molding system is provided, which may include a gas supply device, a plasticizing device, an injection device and a vehicle glass encapsulation mould, wherein the gas supply device is connected with the plasticizing device and adapted to supply at least one gas to the plasticizing device, the plasticizing device is adapted to plasticize a raw material to form a solution and mix the gas and the solution to form a mixed solution having bubbles, and the injection device is connected with the plasticizing device and adapted to inject the mixed solution into a cavity of the vehicle glass encapsulation mould. [0010] One aspect of the present disclosure includes configuring the gas supply device connecting with the plasticizing device, and supplying at least one gas to the plasticizing device to form a mixed solution having bubbles. When the mixed solution having bubbles is injected by the injection device to the cavity of the vehicle glass encapsulation mould, the bubbles will expand due to change of external pressure. Accordingly, the expansion of the bubbles may compensate for the shrinking of the mixed solution, which thereby alleviates the problem of shrinking.

[0011] In some embodiments, the injection molding system may be provided with an exhaust device which is adapted to exhaust a gas in the cavity of the vehicle glass encapsulation mould while the mixed solution is injected into the cavity. By means of the exhaust device, the cavity of the vehicle glass encapsulation mould may be exhausted while the mixed solution is injected into the cavity, which thereby increases surface smoothness of the vehicle glass encapsulation.

[0012] In one embodiment, a method of injection molding is provided, which may include: plasticizing a raw material to form a solution; supplying at least one gas to the raw material during the plasticizing; mixing the solution and the gas together to form a mixed solution having bubbles; and injecting the mixed solution into a cavity of a vehicle glass encapsulation mould to form a vehicle glass encapsulation.

[0013] One aspect of the present disclosure includes supplying gas while plasticizing the raw material to form the mixed solution having bubbles. When the mixed solution having bubbles is injected to the cavity of the vehicle glass encapsulation mould, the bubbles will expand due to change of external pressure. Accordingly, the expansion of the bubbles may compensate for the shrinking of the mixed solution, which thereby alleviates the problem of shrinking.

[0014] In some embodiments, injecting the mixed solution into the cavity of the vehicle glass encapsulation mould may include: exhausting a gas in the cavity of the vehicle glass encapsulation mould while injecting the mixed solution. By doing this, the bubbles formed on a surface of the vehicle glass encapsulation may be removed, which thereby increases surface smoothness of the vehicle glass encapsulation.

[0015] In one embodiment, a vehicle glass encapsulation is provided, which has microvoids formed therein.

[0016] The microvoids may prevent the deformation of the vehicle glass encapsulation, thus increasing yield of the vehicle glass encapsulation. Further, the microvoids may reduce a weight of the vehicle glass encapsulation, thus decreasing production cost of the vehicle glass encapsulation.

[0017] In one embodiment, a vehicle window including the vehicle glass encapsulation is provided.

[0018] The microvoids may prevent the deformation of the vehicle glass encapsulation, thus increasing the yield of the vehicle window. Further, the microvoids may reduce a weight of the vehicle window, thus decreasing production cost of the vehicle window.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 schematically illustrates a rear quarter window in prior art;

[0020] FIG. 2 schematically illustrates an injection molding system according to one embodiment of the present disclosure;

[0021] FIG. 3 schematically illustrates a flow chart of a method of injection molding according to one embodiment of the present disclosure;

[0022] FIG. 4 schematically illustrates a front view of a vehicle window according to one embodiment of the present disclosure; and

[0023] FIG. 5 schematically illustrates a rear view of the vehicle window shown in FIG. 4.

DETAILED DESCRIPTION

[0024] Embodiments of the present disclosure provide an injection molding system and a method of injection molding for forming a vehicle glass encapsulation. According to the present disclosure, in the process of plasticizing a raw material, a gas is mixed in the raw material to form a mixed solution having bubbles. When the mixed solution having bubbles is injected in a mould cavity, the bubbles may expand due to the change of external pressure. Accordingly, the expansion of the bubbles may compensate for the shrinking of the mixed solution, which thus alleviates the problem of shrinking. Further, a vehicle glass encapsulation manufactured using the injection molding system, together with a vehicle window including the vehicle glass encapsulation not only meet a design specification, but also have a high yield.

[0025] Embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings.

[0026] FIG. 2 schematically illustrates an injection molding system according to one embodiment of the present disclosure. Referring to FIG. 2, the injection molding system may include: a gas supply device 100, a plasticizing device 200, an injection device 300 and a vehicle glass encapsulation mould 400.

[0027] The gas supply device 100 is connected with the plasticizing device 200 and is adapted to supply at least one gas to the plasticizing device 200. Specifically, the gas supply device 100 may include a gas bottle 101, a processing unit 102 and a control unit 103.

[0028] The gas bottle 101 is adapted to store gas. In some embodiments, the gas bottle 101 may store nitrogen gas which doesn't contaminate the environment and meets the demand for low carbon. In some embodiments, one or more of carbon dioxide gas, inert gas and compressed gas may be used in the injection molding system, which should not limit the scope of the disclosure. [0029] The processing unit 102 is connected with the gas bottle 101 and is adapted to adjust a pressure of the gas supplied to the plasticizing device 200 from the gas bottle 101. In some embodiments, the processing unit 102 may be an air valve.

[0030] The control unit 103 is connected with the processing unit 102 and is adapted to control a timing of gas supply. The timing of gas supply refers to a start time and a time duration of gas supply. Under control of the control unit 103, gas is supplied after a raw material is fed into the plasticizing device 200. Thus, the start time of gas supply to the plasticizing device 200 can be controlled. By controlling the time duration of gas supply, the gas supply device 100 can control an amount of gas supplied to the plasticizing device 200, which in turn controls dimensions of bubbles in a mixed solution.

[0031] Specifically, the control unit 103 may include an electromagnetic switch connected with the processing unit 102, and a clock unit which is adapted to control the electromagnetic switch to be switched on or off. In a switched-on state, the gas, whose pressure has been adjusted by the processing unit 102, is supplied. In a switched-off state, gas supply is stopped. In some embodiments, the clock unit may be a virtual unit implemented by a computer program. In some embodiments, the clock unit may be a circuit which can provide a clock signal. The rising edge of the clock signal may trigger the electromagnetic switch to be switched on, while the falling edge of the clock signal may trigger the electromagnetic switch to be switched off, thus realizing a control of the start time of gas supply. A time duration of a high level of the clock signal represents a time duration where the electromagnetic switch is switched on, thus realizing a control of the time duration of gas supply.

[0032] It should be noted that the greater the amount of the gas which is mixed into the solution formed by the plasticized raw material, the bigger the bubble in the mixed solution, while the less the amount of the gas which is mixed into the solution formed by the plasticized raw material, the smaller the bubble in the mixed solution. In other words, if the gas flow remains the same, the longer the time duration of gas supply controlled by the control unit 103, the bigger the bubble (correspondingly, the bigger the microvoid in the vehicle glass encapsulation); and the shorter the time duration of gas supply controlled by the control unit 103, the smaller the bubble (correspondingly, the smaller the microvoid in the vehicle glass encapsulation).

[0033] It should be noted that the gas supply device 100 is not limited to the configuration shown in FIG. 2. In some embodiments, the gas supply device 100 may further include a compressor and a controller. The compressor is adapted to provide compressed gas having a certain gas pressure. The controller is connected with the compressor and is adapted to control a start time and a time duration of gas supply from the compressor. As such, the gas supply device 100 can supply compressed gas to the plasticizing device 200, where the compressed gas is low priced, which may decrease production cost.

[0034] The plasticizing device 200 is adapted to plasticize a raw material to form a solution and mix the gas and the solution to form a mixed solution having bubbles. In some embodiments, the plasticizing device 200 may include a feeding cylinder 201, a barrel 202 and a heating unit 203.

[0035] The feeding cylinder 201 is adapted to feed the raw material. In some embodiments, the raw material may be polyvinylchloride (PVC) particles or Thermoplastic Elastomer (TPE) particles. In some embodiments, other raw materials may be used.

[0036] The barrel 202 is provided with a gas inlet communicated with the gas supply device 100 and a feed inlet communicated with the feeding cylinder 201. The barrel 202 has a hollow cavity, where the gas supplied from the gas supply device 100 passes through the gas inlet to the cavity, and the raw material fed from the feeding cylinder 201 passes through the feed inlet to the cavity. It should be noted that the gas inlet and the feed inlet may be provided with a one-way valve which permits only entrance into the cavity. Therefore, gas and raw material entering into the barrel 202 may be confined by the one-way valve in the barrel 202, which thereby improves the performance of sealing the gas and raw material in the barrel 202. The gas and raw material sealed in the barrel 202 may be mixed and be plasticized in the barrel 202.

[0037] The heating unit 203 is adapted to heat the barrel 202 to plasticize the raw material in the barrel 202. During plasticizing, the particle raw material is heated to a glass transition temperature to form a fluidized solution. It should be noted that, for a given particle raw material, if gas is not used, the glass transition temperature is generally high, while if gas is used, the glass transition temperature is lowered since a mixed solution having bubbles is formed. The bubbles can increase fluidity of the mixed solution. Specifically, when PVC particles or TPE particles are used as the raw material, the heating temperature may be set between 100°C and 200°C, which is lower than that where gas is not used. As a result, time required for the heating and a time period of injection molding can be shortened, and production efficiency can be improved.

[0038] The heating unit 203 may be a resistance wire. The heating principle and structure of the resistance wire are known to those skilled in the art, which will not be described in detail herein.

[0039] It should be noted that the plasticizing device 200 is not limited to the configuration shown in FIG. 2. The plasticizing device 200 may be a piston structure, which may include a cylinder and a piston inside the cylinder, wherein the piston may push a raw material into the cylinder. A wall of the cylinder is provided with an air inlet through which gas may flow into the cylinder. A heating unit is disposed on the outside of the cylinder wall, through which the raw material in the cylinder can be plasticized.

[0040] The injection device 300 is connected with the plasticizing device 200 and is adapted to inject the mixed solution into a cavity of the vehicle glass encapsulation mould 400. In some embodiments, the injection device 300 may include a screw 301 and a motor (not shown) and a feed outlet 302. The motor and the feed outlet 302 are disposed at opposite ends of the screw 301, respectively.

[0041] The feed outlet 302 is communicated with the cavity of the vehicle glass encapsulation mould 400.

[0042] The screw 301 is embedded in the barrel 202. The screw 301 may rotate under the drive of the motor and travel towards the feed outlet 302, so as to apply pressure to the mixed solution in the barrel 202. The mixed solution is thus injected from the feed outlet 302 to the cavity of the vehicle glass encapsulation mould 400. In some embodiments, a first screw thread may be provided on the inner wall of the barrel's cavity. And a second screw thread, which matches the first screw thread, may be provided on the wall of the screw 301. Under the force of the screw 301, the mixed solution in the barrel 202 may be pushed out through the feed outlet 302 and filled within the cavity of the vehicle glass encapsulation mould 400. Here, the strength driving the screw 301 to move in the barrel 202 is the injection force.

[0043] In addition, the rotation of the screw 301 under the drive of the motor, may not only drive the raw material and gas to be uniformly mixed between the screw 301 and the inner wall of the barrel's cavity, but also accelerate the process of plasticizing. In some embodiments, the screw 301 may rotate about the axis OO' .

[0044] It should be noted that the injection device 300 is not limited to the configuration shown in FIG. 2. It may be other suitable devices which can inject the mixed solution into the cavity of the vehicle glass encapsulation mould 400. The structure of the injection device 300 is not limited to the examples.

[0045] The cavity of the vehicle glass encapsulation mould 400 matches the vehicle glass encapsulation to be formed. After the mixed solution having bubbles is injected into the cavity of the vehicle glass encapsulation mould 400, the mixed solution turns into an elastomeric state on cooling. After this, the mixed solution further cools and solidifies to form the vehicle glass encapsulation. In the process of forming the vehicle glass encapsulation, natural shrinking may occur with the decrease of external temperature, meanwhile, the bubbles may expand due to a pressure change as the external pressure is reduced (there is a pressure difference between the closed space in the barrel 202 and the cavity of the vehicle glass encapsulation mould 400). The expansion of the bubbles may compensate for the shrinking of the mixed solution, which thereby alleviates the problem of shrinkage of the vehicle glass encapsulation.

[0046] It should be noted that, in the prior art, not only an injection pressure is applied to drive the screw 301, but also a holding pressure is applied to eliminate the gap between the cavity and the mixed solution which is generated due to shrinking. As the problem of shrinking is alleviated, the holding pressure is thus no longer required or only a small holding pressure is applied in embodiments of the present disclosure, which in turn avoids glass cracking caused by too much holding pressure, and increases the yield.

[0047] In addition, the mixed solution described in the present disclosure contains bubbles, which makes the mixed solution have good fluidity. Therefore, a small injection pressure is needed compared with the prior art, which may also lower the possibility of glass cracking. Further, the good fluidity of the mixed solution in turn provides a better filling of the vehicle glass encapsulation mould 400, which is especially suitable for a vehicle glass encapsulation having a complex profile.

[0048] Further, there are a plurality of microvoids formed in the finished vehicle glass encapsulation, which may save raw materials and decrease a weight of the finished vehicle glass encapsulation.

[0049] In some embodiments, the injection molding system may be provided with an exhaust device which is adapted to exhaust a gas in the cavity of the vehicle glass encapsulation mould while the mixed solution is injected into the cavity.

[0050] In some embodiments, at least one exhaust hole may be configured on the vehicle glass encapsulation mould to serve as the exhaust device. The diameter of the exhaust hole may be designed so that the mixed solution may not leak out while allowing exhausting of the gas. In some embodiments, there may be a plurality of exhaust holes, and the plurality of exhaust holes may be distributed evenly on the vehicle glass encapsulation mould to exhaust uniformly, which thus facilitates a smooth surface of a vehicle glass encapsulation with large area. Therefore, other than the advantages mentioned above, the injection molding system provided with the exhaust device can further prevent bubbles from forming on the surface of the vehicle glass encapsulation.

[0051] In some embodiments, the exhaust device may be at least one exhaust needle disposed on the vehicle glass encapsulation mould. The exhaust needle may let out the gas on the surface of the vehicle glass encapsulation. In some embodiments, for ornamental purposes, the exhaust needle may be disposed at a position in the vehicle glass encapsulation mould corresponding to a backside of the vehicle glass encapsulation. The phrase "a backside of the vehicle glass encapsulation", as used here, is intended to refer to a side of the vehicle glass encapsulation which is in contact with the vehicle body after the vehicle glass encapsulation is assembled on the vehicle.

[0052] In some embodiments, the exhaust device may be an evacuating device connected with the vehicle glass encapsulation mould. The evacuating device may pump out the gas in the vehicle glass encapsulation. In spite of a high price, the evacuating device has good controllability, which can guarantee exhaust effect.

[0053] Embodiments of the present disclosure provide a method of injection molding. FIG. 3 schematically illustrates a flow chart of a method of injection molding according to one embodiment of the present disclosure. The method of injection molding may include the steps as follows.

[0054] Step SI, plasticize a raw material to form a solution; [0055] Step S2, inlet at least one gas while plasticizing the raw material;

[0056] Step S3, mix the solution and the gas together to form a mixed solution having bubbles; and

[0057] Step S4, inject the mixed solution into a cavity of a vehicle glass encapsulation mould to form a vehicle glass encapsulation.

[0058] Hereunder, the method of injection molding will be described in detail in conjunction with the injection molding system shown in FIG. 2.

[0059] In SI, a raw material, such as PVC particles or TPE particles, is fed into the feeding cylinder 201, and then enters the cavity of the barrel 202 through the feed inlet. After this, the heating unit 203 heats the raw material in the barrel 202 to form a solution.

[0060] In S2, under the control of the control unit 103 of the gas supply device 100, at least one gas is supplied into the cavity of the barrel 202 through the gas inlet. For example, nitrogen gas may be supplied. In some embodiments, carbon dioxide gas or a mixture of carbon dioxide gas and nitrogen gas may be supplied.

[0061] It should be noted that the greater the amount of the gas which is mixed into the solution, the bigger the bubble, further the bigger the microvoids formed in the vehicle glass encapsulation; while the less the amount of the gas which is mixed into the solution, the smaller the bubble, further the smaller the microvoids formed in the vehicle glass encapsulation. Therefore, the size of the bubbles and the microvoids can be controlled by adjusting the gas flow and the time duration of gas supply.

[0062] In S3, the gas and the raw material are sealed in the barrel 202 by the one-way valve which permits only entrance into the cavity, which thereby improves the sealing performance of the barrel 202. The screw 301 embedded in the barrel 202 is driven by the motor to rotate about the axis OO', so that the solution and gas between the screw 301 and the inner wall of the barrel's cavity may be mixed uniformly, and form the mixed solution having bubbles.

[0063] It should be noted that the processes of plasticizing a raw material, supplying gas and rotating the screw to mix the raw material and gas may be performed simultaneously.

[0064] Because a mixed solution having bubbles is formed after the gas is supplied, the fluidity of the mixed solution is improved due to the bubbles. Accordingly, a glass transition temperature in the process of plasticizing is lowered. In the embodiment, PVC particles or TPE particles are used as the raw material, and the heating temperature is between about 100°C and about 200°C.

[0065] In S4, the screw 301 forces the mixed solution into the cavity of the vehicle glass encapsulation mould 400 under the injection pressure. After the mixed solution having bubbles is injected into the cavity of the vehicle glass encapsulation mould 400, the mixed solution turns into an elastomeric state on cooling. Afterwards, the mixed solution further cools and solidifies to form the vehicle glass encapsulation. The expansion of the bubbles may compensate for the shrinking of the mixed solution, which thereby alleviates the problem of shrinkage of the vehicle glass encapsulation.

[0066] It should be noted that, after the mixed solution is injected into the cavity, a high temperature in the cavity may adversely inhibit the solidification, while a low temperature in the cavity may excessively speed up the solidification, which may affect the bubbles' compensation for the shrinking. In a preferable embodiment, after the mixed solution is injected into the cavity, a temperature in the cavity may be maintained from about 30°C to about 50°C.

[0067] In some embodiments, a holding pressure, which is less compared with the prior art where gas is not used, may be applied to the screw 301 after the cavity is filled up, to maintain an injection state. Thus, the newly injected mixed solution may fill the gap between the cavity and the mixed solution which is caused by shrinking. It should be noted that the holding pressure is not necessary. In the case that the shrinking is eliminated, the holding pressure can be omitted, and only the injection pressure is adopted for injection purpose. As a result, the processes are simplified, the injection molding cycle is shortened and the manufacturing efficiency is improved.

[0068] Correspondingly, embodiments of the present disclosure provide a vehicle glass encapsulation and a vehicle window including the vehicle glass encapsulation. FIG. 4 and FIG. 5 schematically illustrate a front view and a rear view of a vehicle window according to one embodiment of the present disclosure, respectively. Hereunder, a quarter window is taken as an example to illustrate, but not intended to limit the scope of the present disclosure.

[0069] The vehicle window includes a triangle glass 500 and a vehicle glass encapsulation 501 formed on the periphery of the triangle glass 500.

[0070] The vehicle glass encapsulation 501 includes a plurality of microvoids. The plurality of microvoids may prevent the deformation of the vehicle glass encapsulation, which thereby increases the yield of the vehicle glass encapsulation. In addition, the plurality of microvoids may reduce a weight of the vehicle glass encapsulation. Further, the plurality of microvoids may save raw materials for forming the vehicle glass encapsulation, which thereby decreases production cost.

[0071] If the microvoids have over large sizes, the microvoids tend to penetrate the vehicle glass encapsulation 501 to form an opening bubble. If the microvoids have over small sizes, the effect of restraining shrinking is not satisfactory. In a preferable embodiment, the microvoids in the vehicle glass encapsulation 501 may have a diameter ranging from about 0.01mm to about 1mm.

[0072] It should be noted that the vehicle glass encapsulation 501 may be formed with the method of injection molding provided in the present disclosure. Other suitable methods may be employed to form the vehicle glass encapsulation 501, which is not limited in the present disclosure.

[0073] Further, the microvoids can reduce weight of the vehicle glass encapsulation 501 and the vehicle window.

[0074] In some embodiments, an assembling component 502 may be disposed on a backside of the vehicle window, which is adapted to assemble the vehicle window to the vehicle body (not shown).

[0075] Although the present disclosure has been disclosed above with reference to preferred embodiments thereof, it should be understood that the disclosure is presented by way of example only, and not limitation. Those skilled in the art can modify and vary the embodiments without departing from the spirit and scope of the present disclosure.