KR102347729B1 - RTM Mold Structure for Rapid Impregnation of matrix resin - Google Patents

Abstract

The RTM mold structure according to the present invention includes an upper mold 10; a plurality of gate units 20 disposed on the upper mold 10; The lower mold 30 coupled in the lower direction of the upper mold 10; sensor units 61 , 63 , 65 disposed on the lower mold 30 ; Injection discharging means 40 installed to penetrate the inside of the lower mold 30 in the vertical direction; and a suction unit 80 for smoothing the flow of the introduced resin by providing a suction force to the runner formed on the upper mold 10; 10,30) check whether the polyurethane (PU) resin flowing into the inside is filled and the pressure inside the mold (10,30), and after the filling of the introduced polyurethane (PU) resin is completed, the resin is cured and converted into a solid state to measure the change in the opening time of the molds 10 and 30 .

Description

RTM Mold Structure for Rapid Impregnation of matrix resin

The present invention relates to an RTM mold structure for high-speed impregnation of a matrix resin, and specifically to an RTM mold structure for high-speed impregnation of polyurethane, which is a low-viscosity, fast-setting matrix thermosetting resin.

As the severity of environmental problems around the world rises, environmental regulations are being strengthened over time, and the automobile industry at the center is setting the goal of reducing _{CO 2 emission.} Vehicle weight reduction is an optimal method to minimize carbon emissions by increasing engine efficiency, and ultimately, it can improve fuel efficiency of automobiles, so weight reduction due to changes in vehicle materials has been concentrated.

In this regard, various studies are being conducted to reduce the weight of the body and chassis. Among various materials, composite material (CFRP), a high-tech composite material, can perform up to 2/3 the weight of aluminum and 5 times the strength, and the largest Because it can achieve a light weight effect, it is actually used a lot in the aircraft field.

Looking at the trends so far in relation to the development of car body parts that require high strength, the high-productivity composite material molding method does not express the desired level of mechanical performance, and the high mechanical performance composite material molding method has a short cycle. Time is not being productive.

In addition, in order to develop a composite material molding method that can satisfy price, productivity, and mechanical performance at the same time, it is necessary to study the matrix material of the composite material and the high productivity molding method.

Most of the prior technical documents related to composite materials focus on improving the impregnation efficiency of fibers and thermoplastic resins and related equipment manufacturing technologies. Patents for this type of molding technology are being applied for mainly by domestic composite material chemical companies.

Composite material manufacturing methods include injection molding, compression molding, reaction injection molding (RIM), structural reaction injection molding (SRIM), and pultrusion molding. ) and high-speed automated manufacturing methods such as Resin Transfer Molding (RTM) are used.

Among the manufacturing methods, as a molding method for manufacturing a fiber-reinforced composite material article, resin transfer molding (RTM) is representative. In RTM, a fiber mat is installed in a mold, resin is injected and impregnated, and then cured and molded. In order to apply RTM to the production of automobile body parts, it is required to develop an injection resin that provides excellent mechanical performance and has a fast curing rate.

As described above, improved performance is important in the automobile field, but there is a need to secure price competitiveness through fast parts production speed and low production cost. In order to manufacture composite material parts for automobiles, it is necessary to study a manufacturing method with high productivity by applying Long Fiber or Woven Fiber.

In order to mass-produce composite material parts for automobiles, the productivity needs to be at least 10 times faster than the existing composite material molding method, so research and development of molding methods are necessary for this. That is, in consideration of the characteristics of the thermosetting resin, specific studies such as a heating method of a mold, a resin injection method, and element technology that can improve the quality of a composite material are required.

As a conventional patent document related to RTM molding technology, Korean Patent Registration No. 10-1151966 can be cited. However, in the prior art, the molding process from the injection of the resin to the impregnation and curing is performed at high speed in a state that prevents the occurrence of a non-flow region of the resin, or to shorten the molding time, increase the production speed, and increase the production. Although the content is disclosed, there is a problem in that there is no provision for a method that can be used for manufacturing a hood panel for an automobile by enabling high-speed impregnation using polyurethane, which is a low-viscosity thermosetting matrix resin.

(Patent Document 1) KR10-1151966 B

An object of the present invention is to provide an RTM mold structure that enables high-speed impregnation using polyurethane, which is a low-viscosity thermosetting matrix resin.

In addition, an object of the present invention is to provide an RTM mold structure capable of manufacturing a front hood panel for an automobile using a thermosetting matrix resin.

The RTM mold structure according to the present invention includes an upper mold 10; a plurality of gate units 20 disposed on the upper mold 10; The lower mold 30 coupled in the lower direction of the upper mold 10; sensor units 61 , 63 , 65 disposed on the lower mold 30 ; Injection discharging means 40 installed to penetrate the inside of the lower mold 30 in the vertical direction; and a suction unit 80 for smoothing the flow of the introduced resin by providing a suction force to the runner formed on the upper mold 10; 10,30) check whether the polyurethane (PU) resin flowing into the inside is filled and the pressure inside the mold (10,30), and after the filling of the introduced polyurethane (PU) resin is completed, the resin is cured and converted into a solid state to measure the change in the opening time of the molds 10 and 30 .

The gate unit 20 includes a gate passage 21 and a mixer 26, respectively, and the gate passage 21 has a plurality of supply passages for supplying isocyanate (ISO) and polyol (POL), and includes a plurality of Feed passages are connected to the mixer 26 .

The sensor units 61 , 63 , and 65 include a temperature sensor 61 , a pressure sensor 63 , and an eddy current sensor 65 .

The polyurethane (PU) resin flowing into the molds 10 and 30 is applied to the manufacture of the front hood panel for automobiles through high-speed impregnation and curing.

An object of the present invention is to provide an RTM mold structure that enables high-speed impregnation using polyurethane, which is a low-viscosity thermosetting matrix resin.

In addition, the present invention can produce a front hood panel for automobiles at high speed using a polyurethane resin having a very short curing time, so high productivity can be expected.

1 is a schematic view showing an RTM mold structure according to the present invention.
2 is a graph showing the viscosity change of the polyurethane applied to the present RTM mold structure.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art completely It is provided to inform you. In the drawings, like reference numerals refer to like elements.

The RTM mold structure according to the present invention may be manufactured integrally or separately from each other, if necessary. In addition, it is possible to omit some components depending on the use form.

In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It will be understood that may also be "connected", "coupled" or "connected".

The RTM mold structure, the term used in the present invention, is a method of processing by injecting a liquid resin in a state in which a reinforcing fiber substrate made of a laminated substrate of reinforcing fiber fabric is disposed between the upper mold and the lower mold, but is limited thereto No, it may be possible even in a state in which the reinforcing fiber substrate is not provided.

Hereinafter, an RTM mold structure according to the present invention will be described with reference to FIG. 1 .

The RTM mold structure is in the lower part of the upper mold 10 , the gate unit 20 disposed on the upper mold 10 , the lower mold 30 coupled in the lower direction of the upper mold 10 , and the lower mold 30 . The base plate 31 arranged, the sensor parts 61, 63, 65 arranged on the lower mold 30, the lower mold support 50 interconnecting the base plate 31 and the lower mold 30, The injection molding discharging means 40 installed by penetrating the inside of the lower mold 30 in the vertical direction, the injection plate 41 to which the lower end of the injection discharging means 40 is fixed, and a state disposed on the lower mold support 50 In the ejection pin elevating cylinder (not shown) that enables the elevating and lowering of the injection product discharging means 40, it is possible to move in the upper direction of the upper mold 10 in a state coupled to the upper end of the upper mold 10 A mold elevating cylinder (not shown), a coupling plate 71 disposed on the side surfaces of the upper mold 10 and the lower mold 30, the slide core part 70 disposed on the side of the RTM mold structure, and the RTM It includes a suction unit 80 that provides a suction force to a runner (not shown) in a state disposed on the side of the mold structure to smooth the flow of the introduced resin.

In the present invention, the resin is introduced in a state where the preform, which is a fiber-reinforced resin, is disposed between the upper mold 10 and the lower mold 30, where the edge of the space where the preform is placed in the lower mold 30 is tapered outward. processed This increases the sealing effect and helps to accurately position the preform. In addition, there is an advantage in that the injection molding is formed without the occurrence of burrs and at the same time, post-processing is not required.

A plurality of gate units 20 are disposed on the upper mold 10 . Specifically, the gate unit 20 includes a gate flow path 21 and a mixer 26 , respectively. The gate passage 21 serves to supply polyurethane (PU), which is a low-viscosity thermosetting matrix resin, and has a plurality of supply passages for supplying isocyanate (ISO) and polyol (POL).

On the other hand, a plurality of supply passages for supplying isocyanate (ISO) and polyol (POL) are connected to the mixer 26 , and the polyurethane (PU) liquid uniformly mixed in the mixer 26 is the upper mold 10 . It is formed in the inward direction and is supplied through a nozzle disposed at the lower end of the runner and the upper mold 10 serving as a passage through which the liquid resin flows.

The mixer 26 is independently disposed in each gate unit 20 , which is necessary in order to minimize problems such as removal of the solidified matrix material after molding.

The runner in the present invention is a passage through which the liquid resin supplied through the gate unit 20 flows in the inner direction of the upper mold 10 . By enabling a uniform flow of the inflowing resin, stable molding of the injection product is possible, but the present invention is not limited thereto, and various arrangements are possible.

As described above, the present invention provides a large area of polyurethane (PU) through the process of applying a multi-point gate without applying a one-point gate in order to rapidly impregnate the matrix resin on the preform structure disposed inside the molds 10 and 30. ) is rapidly impregnated with resin.

The ejection pin elevating cylinder provides a driving force to the injection plate 41 to enable ascending and descending, thereby elevating and lowering the injection-molded product discharge means 40 fixed to the injection plate 41 . That is, after the resin introduced into the RTM mold structure is solidified, the injection product discharging means 40 pushes up the lower end of the solidified resin product to facilitate discharge from the RTM mold structure.

The coupling plate 71 enables precise positioning between the upper mold 10 and the lower mold 30, and the upper mold 10 is accurately matched on the lower mold 30 during the injection operation through the RTM mold structure. check that it has been

The slide core part 70 operates in an inclined direction during the opening and closing of the mold, and since it is a general structure constituting the mold, a description thereof will be omitted.

The sensor units 61 , 63 , and 65 include a temperature sensor 61 , a pressure sensor 63 , and an eddy current sensor 65 . Monitoring is carried out by checking whether the polyurethane (PU) resin is filled in the mold and the pressure inside the mold through the temperature sensor 61 and the pressure sensor 63 to check whether the filling amount of the polyurethane (PU) resin is appropriate. do. In addition, it is possible to measure the opening time of the mold by measuring whether the liquid resin is cured and changed to a solid state after the polyurethane (PU) material is filled through the eddy current sensor 65 .

In the suction part 80, the resin flowing through the gate unit 20 and the runner flows quickly before it hardens along the inside of the mold structure consisting of the lower mold 30 and the upper mold 10 and uniformly distributes high quality. The key to achieving this is to support the natural flow of the resin by creating a relatively low pressure environment to support the rapid flow of the resin. That is, the resin introduced through the gate unit 20 of the present invention is impregnated at high speed onto the fiber mat disposed between the lower mold 30 and the upper mold 10, so that the fiber-reinforced composite material of good quality within a short time goods can be produced.

Polyurethane (PU) applied to the present invention is a low-viscosity, fast-setting thermosetting matrix resin, which is formed by a polymer addition reaction of a compound having two hydroxyl groups (-OH) and a polyfunctional isocyanate (-NCO). It is a high molecular weight substance. In order to apply the polyurethane (PU) to the front hood panel, which is an automobile exterior, heat resistance is required in the on-line electrodeposition painting process, and a short curing time is required for productivity.

The polyurethane (PU) has physical properties as shown in Table 1 below, and the basic physical properties are very good.

Properties Value E-Modulus(Mpa) 2,400 Flexural Strength (Mpa) 105 Fracture Toughness(J/m2) 430 Continuous use Temp.() 115 HeatDeflection Temp.() 112 Viscosity at processing temp. (mPas) <30

Meanwhile, there are few cases of composite material manufacturing using polyurethane (PU) until now. In the present invention, a low-viscosity fast curing system is applied to have a low-viscosity retention time of about 30 seconds as shown in FIG. 2, and rapidly harden. Configure the system to have

Next, an operation process of the RTM mold structure will be described with reference to FIG. 1 again.

First, a liquid polyurethane (PU) resin is supplied through a plurality of gate units 20 disposed on the upper mold 10 . The supplied liquid resin is impregnated onto the preform structure disposed between the molds 10 and 30 through the runner in the upper mold 10 . In the above process, through the sensor parts 61, 63, 65, whether the polyurethane (PU) resin is filled in the mold and the pressure inside the mold are checked, and after the filling of the polyurethane (PU) material is completed, the liquid resin is cured to a solid state. Measure the mold opening time by measuring whether the The introduced resin flows in both directions of the lower mold 30 through the suction function of the suction unit 80 to completely fill the runner, followed by cooling.

As described above, the RTM mold structure according to the present invention enables high-speed impregnation using polyurethane, which is a low-viscosity thermosetting matrix resin, and at the same time, uses a polyurethane resin with a very short curing time at high speed for automobile front hood panel. can be produced, and high productivity can be expected.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments described above. That is, a person of ordinary skill in the art to which the present invention pertains can make numerous changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications are possible. Equivalents are to be considered as falling within the scope of the present invention.

10: upper mold
20: gate unit
30: lower mold
40: injection molding means
50: lower mold support
61, 63, 65: sensor unit
70: slide core part
80: suction unit

Claims (4)

upper mold 10;
a plurality of gate units 20 disposed on the upper mold 10;
The lower mold 30 coupled in the lower direction of the upper mold 10;
Injection discharging means 40 installed to penetrate the inside of the lower mold 30 in the vertical direction;
a lower mold support 50 interconnecting the base plate 31 disposed under the lower mold 30 and the lower mold 30;
sensor units 61 , 63 , 65 disposed on the lower mold 30 ;
The lower mold 30 is disposed on the sides of the upper mold 10 and the lower mold 30 to enable precise positioning between the upper mold 10 and the lower mold 30 during the injection operation through the RTM mold structure. ) on the coupling plate 71 to check whether the upper mold 10 is correctly matched;
It includes a;
The plurality of gate units 20 are formed symmetrically with respect to the center of the upper mold 10 to enable a uniform flow of the inflow resin and stable molding of the injection product,
The sensor units 61, 63 and 65 include a temperature sensor 61, a pressure sensor 63, and an eddy current sensor 65,
The edge of the space where the preform, which is a fiber-reinforced resin, is placed on the lower mold 30 is tapered to the outside,
Check whether the polyurethane (PU) resin flowing into the mold 10, 30 through the sensor unit 61, 63, 65 is filled and the pressure inside the mold 10, 30, and the introduced polyurethane (PU) to measure the opening time of the mold (10, 30) by measuring whether the resin is cured and changed to a solid phase after the filling of the resin is completed,
RTM mold structure.
The method of claim 1,
The gate unit 20 includes a gate passage 21 and a mixer 26, respectively,
The gate passage 21 has a plurality of supply passages for supplying isocyanate (ISO) and polyol (POL), and the plurality of supply passages are connected to the mixer 26 ,
RTM mold structure.
3. The method of claim 2,
Polyurethane (PU) resin flowing into the mold (10, 30) is applied to the manufacture of the front hood panel for automobiles through high-speed impregnation and curing,
RTM mold structure.
In the operating method using the RTM mold structure according to claim 1,
supplying a liquid polyurethane (PU) resin through a plurality of gate units 20 disposed on the upper mold 10 ;
impregnating the supplied liquid resin onto the preform structure disposed between the molds 10 and 30 through the runner in the upper mold 10;
Check whether the polyurethane (PU) resin is filled in the mold and the pressure inside the mold through the sensor parts (61, 63, 65), and whether the liquid resin is cured and changed to a solid state after the filling of the polyurethane (PU) material is completed Measuring the opening time of the mold by measuring;
The introduced resin flows in both directions of the lower mold 30 through the suction function of the suction unit 80 to fill the runner, followed by cooling; and
After the resin introduced into the RTM mold structure is solidified, the injection product discharging means 40 performs an action to push up the lower end of the solidified resin product, thereby discharging from the RTM mold structure; including ,
How it works with the RTM mold structure.

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