KR101968649B1 - Rear Injection Under-Cover for Vehicles to Improve Durability and Its Manufacturing Method - Google Patents

Abstract

The present invention relates to a rear injection under-cover for a vehicle to improve durability and a production method thereof and, more specifically, to a rear injection under-cover for a vehicle to improve NVH performance and durability of the vehicle′s noise, vibration, and harshness, and a production method thereof.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rear injection undercover for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular rear injection under cover for improving durability and a method of manufacturing the same. More particularly, the present invention relates to a rear injection under cover for a vehicle, which is improved in durability by improving the NVH performance and durability of noise, vibration, harshness, PPGF and GF are needle-punched and fiber-reinforced PPGF blend fabrics are supplied between the PET layer and the PET layer to reduce weight loss and glass fiber separation in the trimming section, thereby improving the dust caused by the glass fiber and improving the weight and cost PP film is supplied between the PET layer and the PPGF blend fabric to maintain the bonding performance. At the same time, after insert molding in the post-spinning launch, additional rigidity is provided by locally extruding only the rim and mounting seating surface on the under cover surface And more particularly, to a vehicle rear-projection under-cover for improved durability and a manufacturing method thereof.

Generally, when the vehicle is running, the vehicle body collides with the atmospheric air, thereby receiving a resistance. Such a resistance is called an air resistance, and the air resistance is largely classified into a drag force and a lift force.

Here, the drag force refers to a resistance force that a vehicle body that directly impacts air while traveling in the opposite direction of travel, and a lift phenomenon refers to a phenomenon that a vehicle body floats due to a pressure difference generated in the upper and lower portions of the vehicle during driving.

Therefore, in the early stage of automobile development, the target air resistance coefficient is set in order to reduce the air resistance as much as possible, and the body shape is determined by carrying out a lot of simulations and wind tunnel tests to achieve the target.

On the other hand, after the basic body shape is determined, various means are provided to improve the aerodynamic performance by reducing the drag and the like, one of which is an undercover installed under the engine room of the vehicle.

This undercover prevents undesirable noises such as road noise from being transmitted to the room through the engine room and dash board while driving, and also prevents dirt from being contaminated by the parts of the engine room, thereby improving durability, thereby improving aerodynamic performance.

In addition, the floor under cover mounted on the floor of the vehicle is installed at the bottom of the engine, the transmission and the cooling fan to protect the engine and the transmission from the external impact, as well as the noise generated from the engine or transmission And prevents foreign matter from entering the interior of the vehicle from the outside.

However, in the conventional undercover, when the air is introduced at a high speed, the inflow air is not directly discharged to the rear lower portion of the vehicle but is dispersedly discharged to a portion opened at both sides of the front wheel to generate a flow loss, There is a problem that the overall air resistance increases during traveling.

In addition, such air resistance lowers the aerodynamic performance of the vehicle, thereby increasing the cooling drag to increase the air-fuel ratio, and the heat generated in the engine room is not discharged smoothly, Problems also arise.

Conventionally, GMT (glass fiber mat thermoplastic) was used as a material of a floor under cover. The GMT sheet refers to a composite material of a plate shape comprising a polypropylene (polyethylene) resin and a glass fiber mat reinforcement, Matrix " refers to a sheet-shaped intermediate article in which glass fiber pads are reinforced in between.

GMT is a composite material for forming parts that has both light weight of plastic and mechanical properties of reinforcement. It is advantageous to obtain desirable physical properties comparatively cheaply by proper combination of matrix resin and reinforcement. However, GMT material has pore Since it is impossible to manufacture different thicknesses depending on the regions, there is almost no sound-absorbing performance, and it is impossible to realize an integral type full under cover due to the compression and injection molding method, and since the density of the material itself is high There is a problem that the total weight of the vehicle is increased.

BACKGROUND ART [0002] Conventional automotive underbarkers for vehicles generally include a cover body formed by mixing or kneading glass fiber and polypropylene into a sheet form, a laminate made of a flame retardant water repellent nonwoven fabric laminated on the upper surface of the cover body, And a method of assembling the resin into a separate molded article.

Since the temperature of the exhaust pipe of the undercover is in the range of about 700 to 800 ° C., the conventional polypropylene resin injection molding can not escape thermal deformation. . However, this is also a factor that hinders the secondary performance of the vehicle such as cost increase and weight increase.

Dust is generated in the glass fiber used for the under cover, dust that is generated when the glass fiber is separated due to the under cover trimming part at the time of work, and there is a problem that flushing or skin troubles are generated due to being seated on the skin of the worker.

Accordingly, it is an object of the present invention to provide an under cover which minimizes the generation of dust due to the use of glass fibers in the manufacture of an under cover, improves the sound absorption performance, and reduces the weight, thereby reducing the cost.

On the other hand, a conventional PP sheet has been provided to prevent peeling due to thermosetting between materials of the PET type, and the PP sheet is melted while thermocompression bonding and the PET series is fused to prevent peeling. While the conventional technique achieves the object of preventing peeling, there is a disadvantage that it is difficult to provide the sound absorbing performance because the PET sheet is melted and the PP sheet is melted to cause deterioration of the breaking performance.

[Patent Document 1] Patent Publication No. 2013-0107627 (published on Mar. 10, 2013) [Patent Document 2] Patent Registration No. 1818050 (Registered on October 10, 2018) [Patent Literature 3] Patent Registration No. 1821499 (Registered on January 17, 2018) [Patent Document 4] Patent Registration No. 1788134 (Registered on October 13, 2017)

SUMMARY OF THE INVENTION The present invention has been made in order to overcome the drawbacks of the prior art, and it is therefore an object of the present invention to provide a method of manufacturing a lightweight material by thermoforming PET, PP and GF needle- The present invention aims at locally injecting the RIB and MTG seating surfaces onto the surface of the under-cover formed by insert molding in the rear injector together with the reinforcing injection member so as to prevent dust and escape according to the work.

Another object of the present invention is to provide an undercoat which is made of PET (polyethylene terephthalate), PPGF blend fabrics and PET, which are punched by needle punching and then subjected to hot pressing to perform press forming and cold forming Thereby preventing the dust and the escape of the glass fiber due to the operation of the glass fiber so as not to generate dust.

Another object of the present invention is to provide a method of manufacturing a metal mold in which the under cover is made of PET (polyethylene terephthalate) and PPGF blend fabric and PET, Thereby preventing the generation of dust due to the operation of the glass fiber.

Another object of the present invention is to provide a method of improving the NVH performance of noise, vibration, and harshness of a vehicle by supplying PPGF blend fabric between PET layers to perform needle punching, Thereby reducing weight and cost for weight reduction and improving sound absorption performance.

Another object of the present invention is to provide a structure in which a lightweighting material can not be implemented solely by rearward injection of a reinforcing injection member on the upper side of an under cover fabric or by forming only a corresponding partial point locally by applying a valve gate And to satisfy the durability in a portion requiring rigidity.

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The present invention comprises a PET envelope layer and an upper PP film, a PPGF blend fabric, a lower PP film, and a PET end layer, which are molded by hot pressing to be integral;

Wherein the PET envelope layer and the PET inner layer layer are made of polyethylene terephthalate and have a weight of 200 to 400 gsm (g / m < 2 >), and the PPGF blend fabric has a glass fiber length of 80 to 100 mm Setting a depth depth at which the glass fiber does not flow outward between the PET skin layer and the PET endothelium layer,

Wherein the upper and lower PP films are formed with perforations at regular intervals,

An under cover which is pre-heated by a hot press and cold-formed;

The insert is formed by insert molding of the rear insert reinforcement in the rear injector, and then the insert and the injection part are locally formed only on the rim and the mounting seat surface on the under cover surface.

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The present invention provides a PET envelope layer made of polyethylene terephthalate and a PET inner layer layer each provided with a yarn of 28 mu m to have a thickness of 3 mm and 300 gsm and to provide a yarn of 28 mu m between the PET envelope layer and the PET inner layer layer Providing a glass fiber composite sheet having a thickness of 9 mm and having a thickness of 800 gsm;

Supplying a top PP film composed of a PP film formed between the PET skin layer and the PPGF blend fabric and supplying a bottom PP film made of a PP film formed between the PPGF blend fabric and the PET inner skin layer;

A hot press preheating step of preheating for 70 to 80 seconds so that the temperature of the hot press is maintained at 180 to 220 DEG C;

A cold forming step of performing cold press molding after hot forming using a hot press to complete the molding of the under cover by maintaining the mold temperature of the cold mold at 15 to 20 캜 and maintaining the cold time of 90 to 110 seconds;

A rear injection molding step in which an under cover is supplied to a mold of a rear injection machine to melt a synthetic resin made of PE, PP, PET or GP to insert insert molding of either a rear insert reinforcing part or an additional injection part; And a control unit.

The present invention relates to an improvement of work performance in preventing dust from being generated due to the operation of glass fiber by preventing the generation of dust by cold forming of a lightweight material made of PET and a fabric obtained by supplying PET to a fabric punched with PP and GF The present invention is also directed to providing a rear injection under cover which enhances rigidity by locally injecting RIB and MTG seat surface portions onto a surface of an under cover which is insert molded in a rear injection machine together with a reinforcing injection member.

In the present invention, the undercovers are made of PET (polyethylene terephthalate), PPGF blend fabrics and PET, and they are punched by needle punching, followed by press molding and cold molding through hot press to produce glass fiber work Thereby preventing dust from being generated and preventing dust from escaping.

In the present invention, undercovers are made of PET (polyethylene terephthalate), PPGF blend fabrics and PET, and after the punched PP is supplied therebetween, the mold is preheated and cold-formed, Thereby preventing dust from being generated and preventing dust from escaping.

In order to improve the NVH performance of noise, vibration, and harshness of a vehicle, PPGF blend fabrics are supplied between PET layers to be needle-punched or fed with a perforated PP film, And the cost is reduced, the high frequency NVH performance is improved while the PP film is inserted, and the sound absorption performance is improved.

In the present invention, a reinforcing injection member is injected rearward on the upper side of the under cover fabric or a structure that can not be realized by a light weight material alone, or a partial gate is locally formed by applying a valve gate (pin point) And it is an object of the present invention to provide an effect of preventing sagging of a product.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a rear injection under cover,
FIG. 2 is a cross-sectional view of a state in which a rear injection under cover fabric of the present invention is joined and needle-
3 is a cross-sectional view of another embodiment of the rear injection under cover fabric of the present invention,
Figure 4 is a cross-sectional view of a rear injection undergarment fabric of the present invention in combination with another embodiment;
Fig. 5 is an enlarged plan view of the recessed portion of the perforated PP film of the present invention
6 is a schematic view illustrating a process of cold forming a lightweight material of the present invention
7 is a plan view of the injection state of the lightweight material of the present invention
8 is an enlarged plan view of a molded state recessed portion of the rear insert reinforcing portion of the present invention
Fig. 9 is an enlarged cross-sectional view of the molding condition of the additional injection part of the present invention
10 is a plan view of the local insert-forming state for the undercover of the present invention
11 is a block diagram showing the most preferred embodiment of the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a state in which a rear end of a rear injection under cover is separated, and FIG. 2 is a cross-sectional view of a state in which a rear injection under cover of the present invention is combined with a needle punching process .

In order to improve the NVH performance of the noise, vibration and harshness of the vehicle, a PP film composed of any one of ordinary or perforated lower side of the nonwoven fabric, PPGP mixed blend of PP and GP blended with needle punching (EN) Provided is a rear injection under cover (10) for reducing weight and cost for lightening by supplying a fabric, improving high frequency NVH (noise) performance, improving sound absorption performance and improving rigidity by improving sag will be.

The under cover 10 comprises a PET envelope layer 20, a PPGF blend fabric 30 and a PET endothelial layer 40. The PET envelope layer 20, the PPGF blend fabric 30, (40) are connected to each other by a needle punching (50a) so as to be integrally formed.

The PET envelope layer 20 and the PET inner layer 40 are made of polyethylene terephthalate and have a yarn thickness of 4 to 12 denier and are made of 200 to 400 gsm (g / m 2) It is preferable to form it so as to have a thickness.

If the PET skin layer 20 and the PET endothelial layer 40 are 200 gsm or less, there is a disadvantage that the NVH performance is largely lowered and the bonding strength is lowered.

When the PET sheath layer 20 and the PET endothelial layer 40 are 400 gsm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, it is preferably 300 gsm.

When the thickness of the PET skin layer 20 and the thickness of the PET endothelial layer 40 is less than 1 mm, there is a disadvantage in that the NVH performance is largely lowered and the bonding strength is lowered.

If the PET sheath layer 20 and the PET inner layer 40 are 5 mm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, the thickness is preferably 3 mm.

The PPGF blend fabric 30 of the present invention has a yarn thickness of 6 to 20 탆 and has a glass fiber length of 80 to 100 mm, When the needle punching 50a is performed in the needle punching process, the depth of the glass fiber does not flow outward by the needles.

When the length of the glass fiber is 80 mm or less, the fiber is separated toward the outside by the needle as the fiber is closer to the short fiber,

When the length of the glass fiber is 100 mm or more, it is supplied to the long fiber so that it is difficult to provide the same weight as that of holding the uniform thickness, and the bonding force is lowered.

Preferably, the PPGF blend fabric 30 has a thickness of 500 to 1,000 gsm and a thickness of 6 to 12 mm.

When the PPGF blend fabric 30 has a particle size of 500 gsm or less, there is a disadvantage that the NVH performance is largely lowered and the binding force is lowered.

The PPGF blend fabric 30 has a disadvantage that the NVH performance is not significantly improved and the bonding strength is not improved when the PPGF blend fabric 30 has a density of 1,000 gsm or more, preferably 750 gsm.

When the PPGF blend fabric 30 has a diameter of 6 mm or less, there is a disadvantage that the NVH performance is largely lowered and the bonding force is lowered.

When the PPGF blend fabric 30 has a diameter of 12 mm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, the PPGF blend fabric 30 preferably has a thickness of 9 mm, By keeping the depth to be low against the length, the glass fiber is prevented from flowing out.

FIG. 3 is a cross-sectional view of a rear injection under cover fabric of the present invention separated from another embodiment, FIG. 4 is a cross-sectional view of a rear injection under cover fabric of the present invention combined with another embodiment, Fig. 3 is an enlarged plan view of the core PP film of the invention.

The under cover 10 comprises a PET envelope layer 20, a PPGF blend fabric 30 and a PET endothelial layer 40. The PET envelope layer 20, the PPGF blend fabric 30, The upper and lower PP films 50 and 51, which are perforated at regular intervals, are supplied and bonded to each other to form an integral body (not shown) .

The PET envelope layer 20 and the PET endothelial layer 40 are made of polyethylene terephthalate and have a yarn thickness of 20 to 35 mu m and are formed to have a weight of 200 to 400 gsm (g / m < 2 & It is preferable to form it so as to have a thickness.

If the PET skin layer 20 and the PET endothelial layer 40 are 200 gsm or less, there is a disadvantage that the NVH performance is largely lowered and the bonding strength is lowered.

When the PET sheath layer 20 and the PET endothelial layer 40 are 400 gsm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, it is preferably 300 gsm.

When the thickness of the PET skin layer 20 and the thickness of the PET endothelial layer 40 is less than 1 mm, there is a disadvantage in that the NVH performance is largely lowered and the bonding strength is lowered.

If the PET sheath layer 20 and the PET inner layer 40 are 5 mm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, the thickness is preferably 3 mm.

The PPGF blend fabric 30 of the present invention can be produced by forming long fibers of 80 to 100 mm in length of glass fibers having a yarn thickness of 20 to 32 탆, , And the depth of depth at which the glass fiber does not flow outward during press molding using the lower PP films (50, 51) is set high.

When the length of the glass fiber is 80 mm or less, the fiber is separated toward the outside by the needle as the fiber is closer to the short fiber,

When the length of the glass fiber is 100 mm or more, it is supplied to the long fiber so that it is difficult to provide the same weight as that of holding the uniform thickness, and the bonding force is lowered.

Preferably, the PPGF blend fabric 30 has a thickness of 500 to 1,000 gsm and a thickness of 6 to 12 mm.

When the PPGF blend fabric 30 has a particle size of 500 gsm or less, there is a disadvantage that the NVH performance is largely lowered and the binding force is lowered.

The PPGF blend fabric 30 has a disadvantage that the NVH performance is not significantly improved and the bonding strength is not improved when the PPGF blend fabric 30 has a density of 1,000 gsm or more, preferably 750 gsm.

When the PPGF blend fabric 30 has a diameter of 6 mm or less, there is a disadvantage that the NVH performance is largely lowered and the bonding force is lowered.

When the PPGF blend fabric 30 has a diameter of 12 mm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, the PPGF blend fabric 30 preferably has a thickness of 9 mm, By keeping the depth to be low against the length, the glass fiber is prevented from flowing out.

The upper and lower PP films 50 and 51 have a thickness of 30 to 100 gsm and a thickness of 0.1 to 0.3 mm. The diameter of the perforations 22 formed at regular intervals is 4 to 6 mm, 9 mm.

When the upper and lower PP films 50 and 51 are 30 gsm or less, there is a disadvantage that the NVH performance is greatly reduced while the bonding performance is improved.

When the upper and lower PP films 50 and 51 are 100 gsm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, 70 gsm is preferable.

If the upper and lower PP films 50 and 51 have a thickness of 0.1 mm or less, the bonding performance and the NVH performance are greatly deteriorated.

When the upper and lower PP films 50 and 51 have a thickness of 0.3 mm or more, the bonding performance is improved, but the NVH performance is not greatly improved, and the perforation 22 is blocked and NVH performance can not be expected. So that the perforation 22 can be maintained at a constant size to some extent even after molding so as to maintain or improve the NVH performance.

FIG. 6 is a schematic view showing a process of cold forming a lightweight material of the present invention, and FIG. 7 is a plan view of an injection state of a lightweight material of the present invention.

After the PET sheath layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 are bound together by the needle punching 50a to be a monolithic fabric, they are cold-formed by the under cover 10.

The molding of the under cover 10 is carried out by preheating the hot press 60 at a temperature of 180 to 220 占 폚 for 70 to 80 seconds to form a PET envelope layer 20 and PPGF blend fabrics 30, The PET endothelial layer 40 is supplied to the preheated hot press 60 and cold-formed to a temperature of 15 to 20 占 폚 for 90 to 110 seconds.

When the temperature of the hot press 60 is 180 占 폚 or lower, there is a disadvantage in that the bonding force is lowered and the rigidity such as tensile strength is lowered. On the other hand, when the temperature is higher than 220 占 폚, Is heated and cooled to 200 deg.

When the cold forming time of the hot press 60 is 90 seconds or less, there is a disadvantage in that the bonding force is lowered and the rigidity such as tensile strength is lowered. When the hot press 60 is 110 seconds or more, So that cold forming is preferably performed for 100 seconds.

After the preheating using the hot press 60, the cold press molding is performed to maintain the molding temperature of the hot press 60 at 180 to 220 deg. C and maintain the molding time of 70 to 80 seconds, To complete.

When the mold temperature of the hot press 60 is maintained at a molding time of 180 DEG C or less and 70 seconds or less, there is a disadvantage that the bonding strength between the PET sheath layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 becomes weak When the mold temperature of the hot press 60 is maintained at 220 ° C or less and at a molding time of 80 seconds or more, the bonding strength between the PET sheath layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 is increased But it is difficult to maintain the appearance quality. Therefore, the mold temperature of the hot press 60 is preferably molded at 20 DEG C for 100 seconds.

The PET envelope layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 are combined to be integral with each other through the needle punching 50a, thereby preventing the folding phenomenon, preventing the peeling phenomenon from occurring, 20 and the PET endothelial layer 40 to improve the NVH performance.

The under cover 10 is press molded through a hot press 60 in a state in which the PET sheath layer 20, the PPGF blend fabric 30 and the PET inner layer 40 are integrally formed by needle punching 50a. The thickness of the rim portion and the portion requiring the outer surface rigidity of the seating surface are 1.0 to 3.0 mm and the thickness to satisfy the NVH performance is 2 to 5 mm.

The upper and lower PP films 50 and 51 having pores 22 are formed between the PET skin layer 20, the PPGF blend fabric 30 and the PET inner skin layer 40, The injection molding is performed with the under cover 10.

The injection of the under cover 10 is performed by preheating the PET envelope layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 by preheating for 70 to 80 seconds so that the temperature of the hot press 60 is maintained at 180 to 220 占 폚, The upper and lower PP films 50 and 51 are inserted into the preheated hot press 60.

When the temperature of the hot press 60 is 190 占 폚 or lower, there is a disadvantage in that the bonding force is lowered and the rigidity such as tensile strength is lowered. When the temperature is higher than 220 占 폚, Is heated to 200 占 폚 to perform injection molding.

When the injection molding time of the hot press 60 is 70 seconds or less, there is a disadvantage in that the bonding force is lowered and the rigidity such as tensile strength is lowered. When the injection molding time is 80 seconds or more, The injection molding is preferably performed for 75 seconds.

After the injection molding using the hot press 60, the cold press molding is performed to maintain the molding temperature of the hot press 60 at 15 to 20 DEG C and maintain the molding time of 90 to 110 seconds, .

When the mold temperature of the hot press 60 is maintained at a molding time of 15 ° C. or less and 100 seconds or less, the upper and lower PP films 50 and 51 are first melted and the PET sheath layer 20 and the PPGF blend fabric 30 are melted, The upper and lower PP films 50 and 51 may be bonded to each other in the case where the mold temperature of the hot press 60 is maintained at 22 deg. There is a disadvantage in that the bonding strength between the PET sheath layer 20 and the PPGF blend fabric 30 and the PET endothelial layer 40 is strengthened first but it is difficult to maintain the quality of the outer appearance. Lt; 0 > C for 100 seconds.

The PET envelope layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 are combined so as to be integrally formed by melting the upper and lower PP films 50 and 51 to prevent the folding phenomenon, And improving the NVH performance by improving the deflection phenomenon caused by the PET sheath layer 20 and the PET endothelial layer 40. [

The upper and lower PP films 50 and 51 are supplied between the PET sheath layer 20 and the PPGF blend fabric 30 and the PET inner layer 40. The under- The thickness of the edge portion 10 and the portion requiring a stiffness outside the mounting seat surface is 1.0 to 3.0 mm and the thickness to satisfy the NVH performance is 2 to 5 mm. ) Is 4 to 6 mm, so that the perforations 22 are not blocked even after the press molding is completed, thereby enhancing the NVH performance.

9 is an enlarged cross-sectional view of a molding condition of the additional injection part of the present invention, and Fig. 10 is a partially enlarged cross-sectional view of the insert insert part of the rear insert- Fig.

A state in which the PET skin layer 20, the PPGF blend fabric 30 and the PET endothelial layer 40 are needle-punched (50a) and fed into the mold;

The upper PP film 50, the PPGF blend fabric 30, the lower PP film 51, and the PET inner layer 40, in which the PET sheath layer 20 and the perforations 22 are formed, And the cold injection molding is performed with the rear injection under cover 10 which further locally reinforces the reinforcement part 100 and the additional injection part 110. [

The cold forming of the rear injection under cover 10 is performed by maintaining the molding temperature of the hot press 60 at 15 to 20 캜 and maintaining the molding time of 90 to 110 seconds to complete the molding of the rear injection under cover 10 will be.

If the mold temperature of the hot press 60 is maintained at a molding time of 15 ° C. or less and 90 seconds or less, there is a disadvantage in that the PP sheathing layer 20 is first melted and the bonding force between the PPGF blend fabric 30 is weakened. When the mold temperature of the glass fiber 60 is maintained at 20 ° C. or more and at a molding time of 110 seconds or more, the PP film 30 is first melted and the bonding strength between the glass fiber PPGF blend fabrics 30 is strengthened. However, It is preferable to mold the mold temperature of the hot press 60 at 20 DEG C for 100 seconds.

The PPGF blend fabric 30 is formed by melting the PET films 20 and 40 and the PP films 50 and 51 so as to be integral with each other, thereby preventing the folding phenomenon and preventing the peeling phenomenon and improving the NVH performance You can.

The PPGF blend fabric 30 is combined with the PP films 50 and 51 so as to be integrated with each other, thereby preventing the folding phenomenon and satisfying the peeling strength between the materials. The thickness of the center portion is set to a stiffness And NVH performance can be improved.

Particularly, by feeding the rear injection under cover 10 and insert molding the rear insert reinforcement 100 and the additional injection part 110, the PP films 50 and 51, the PET 20 and 40, The composite material is doubly injection-molded while the blend fabric 30 is positioned. Thus, the weight of the lightweight material is reduced while the durability is satisfied in a portion requiring rigidity, and at the same time, rigidity for preventing sagging is greatly improved.

After the PET 20, 40, the PP film 20 and the PPGF blend fabric 30 are fed, the rear insert reinforcement 100 and the additional injection part (not shown) are formed on the surface of the under cover 10, 110), the thickness of the rim and the portion requiring the outer surface rigidity of the mounting (MTG) are locally additionally injected so as to have a thickness of 1.0 to 3.0 mm, and the NVH performance The diameter of the perforation 22 is 4 to 6 mm and the perforation 22 is maintained without being clogged even after completion of the press forming, thereby improving the NVH performance It will be possible.

After the under cover 10 is cold formed, the rear insert reinforcement 100 is exposed to the lower side and the lower side of the under cover 10 in a state of being supplied to the mold of the hot press 60 as shown in FIG. 8, It is possible to perform the rear injection, and as shown in Fig. 9, it is possible to perform the molding by rearward injection at a portion where the additional injection portion 110 needs to be locally reinforced, The reinforcing part 100 and the additional injection part 110 can be selected to be formed, so that the desired part is reinforced through the rear insert reinforcing part 100 and the effect that the additional part 110 of the under cover 10 is injected The rim portion and the mounting seat portion are locally subjected to additional injection to improve the bending strength, thereby providing an effect of greatly improving the rigidity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

end. (S10)

A PET envelope layer 20 and a PET inner layer layer 40 made of polyethylene terephthalate each having a thickness of 3 mm and a thickness of 300 gms are provided to provide a yarn thickness of 4 to 12 denier and the PET envelope layer 20 and the PET inner layer layer 40 to provide a PPGF blend fabric 30 having a thickness of 9 mm and having a weight of 500 gsm.

I. The needle punching binding step (S20)

The PET envelope layer 20, the PPGF blend fabric 30, and the PET endothelial layer 40 are fed and bound together through the needle punching 50a.

All. Hot press preheating step (S30)

Preheating is performed for 70 to 80 seconds so that the temperature of the hot press 60 is maintained at 180 to 220 deg.

la. In the cold forming step (S40)

After preheating by using the hot press 60, cold press molding is performed, and molding of the under cover 10 is completed by maintaining the mold temperature of the cold mold at 15 to 20 DEG C and maintaining the cold time of 90 to 110 seconds .

hemp. In the rear injection molding step S50,

The under cover 10 is supplied to the mold of the rear injection machine to melt the synthetic resin made of PE, PP, PET or GP to insert-insert any one of the rear insert reinforcing part 100 and the additional injection part 110.

The insert RIB and the mounting MTG may be formed by insert molding such that the insert reinforcing part 100 is integrally enclosed by supplying the under cover 10 or by forming the additional injection part 110 on the surface of the under cover 10, The seating surface only provides additional stiffness through additional local injection.

end. (S10)

A PET envelope layer 20 made of polyethylene terephthalate and a PET inner layer 40 are provided so as to have a thickness of 3 mm and a thickness of 300 gms by providing a yarn of 28 mu m each and the PET envelope layer 20 and the PET inner layer layer 40 To provide a PPGF blend fabric 30 having a thickness of 9 mm and having a basis weight of 800 gsm;

An upper PP film 50 made of a PP film punched between the PET sheath layer 20 and the PPGF blend fabric 30 is supplied and the PPGF blend fabric 30 and the PET inner skin layer 40 And a lower PP film 51 made of a PP film having a perforation 22 formed therebetween.

I. Hot press preheating step (S20)

And the preheating is performed for 75 seconds so that the temperature of the hot press 60 is maintained at 200 占 폚.

All. In the cold forming step (S40)

After preheating by using the hot press 60, cold press molding is performed, and molding of the under cover 10 is completed by maintaining the mold temperature of the cold mold at 15 to 20 DEG C and maintaining the cold time of 90 to 110 seconds .

la. In the rear injection molding step S50,

The under cover 10 is supplied to the mold of the rear injection machine to melt the synthetic resin made of PE, PP, PET or GP to insert-insert any one of the rear insert reinforcing part 100 and the additional injection part 110.

The insert RIB and the mounting MTG may be formed by insert molding such that the insert reinforcing part 100 is integrally enclosed by supplying the under cover 10 or by forming the additional injection part 110 on the surface of the under cover 10, The seating surface only provides additional stiffness through additional local injection.

In order to improve the NVH performance, it is possible to reduce weight and to prevent the glass fibers from escaping from the trimming portion by improving the dust caused by the glass fiber, to reduce the weight and cost, It is an object of the present invention to provide a reinforced portion by injection by injection and to provide a very useful invention for improving the rigidity by improving the bending strength by locally injecting only the rim portion and the mounting seat portion on the under cover surface.

10: undercover 20: PET sheath layer
22: perforation 30: PPGF blend fabric
40: PET inner skin layer 50: upper PP film
50a: Needle punching 51: Lower PP film
60: hot press 100: rear insert reinforcement
110: additional injection part

Claims (14)

delete delete delete delete delete delete A PET envelope layer 20 and an upper PP film 50, a PPGF blend fabric 30, a lower PP film 51 and a PET endothelial layer 40 and is molded by a hot press 60 to be integrated;
The PET envelope layer 20 and the PET inner layer 40 are made of polyethylene terephthalate and have a weight of 200 to 400 gsm (g / m 2). The PPGF blend fabric 30 has a glass fiber length A depth of cut is set such that the glass fiber does not flow outward between the PET outer skin layer 20 and the PET inner skin layer 40 by using long fibers of 80 to 100 mm,
The upper and lower PP films (50, 51) are provided with perforations (22) at regular intervals,
An under cover 10 for preheating the hot press 60 and forming the hot press 60 by cold;
After the insert cover 10 is inserted into the rear insert enhancer 100 from the rear injector, the injector 110 is injection molded on the inner surface of the under cover 10, A vehicle rear injection under cover for improved durability.
8. The method of claim 7,
The PET envelope layer 20 and the PET endothelial layer 40 are made of polyethylene terephthalate and are formed to have a thickness of 1 to 5 mm by providing a yarn of 20 to 35 탆. Automotive rear injection undercover.
8. The method of claim 7,
Wherein the PPGF blend fabric 30 provides a yarn of 20 to 35 mu m and has a weight of 500 to 1,000 gsm.
delete 8. The method of claim 7,
The PET envelope layer 20 and the upper PP film 50, the PPGF blend fabric 30, the lower PP film 51 and the PET inner layer 40 are supplied to the preheated hot press 60, And the molding is performed for 90 to 110 seconds.
8. The method of claim 7,
The upper and lower PP films 50 and 51 are formed such that the perforations 22 are formed to a size of 4 to 6 mm and the interval L of the perforations 22 is 5 to 9 mm, Is formed so as not to be blocked.
delete A PET envelope layer 20 made of polyethylene terephthalate and a PET inner layer 40 are provided so as to have a thickness of 1 to 5 mm and a thickness of 200 to 400 gsm, Providing a PPGF blend fabric 30 having a thickness of 6 to 12 mm and having a weight of 500 to 1,000 gsm by providing a yarn of 20 to 32 탆 between the endothelial layer 40;
An upper PP film 50 made of a PP film punched between the PET sheath layer 20 and the PPGF blend fabric 30 is supplied and the PPGF blend fabric 30 and the PET inner skin layer 40 (S10) for supplying a lower PP film (51) made of a PP film having a perforation (22) formed therebetween;
A hot press preheating step (S20) for preheating the hot press (60) for 70 to 80 seconds to maintain the temperature at 180 to 220 deg.
After the preheating using the hot press 60, the cold press molding is performed to maintain the mold temperature of the cold metal at 15 to 20 DEG C and maintain the cold time of 90 to 110 seconds, Forming step S40;
A rear injection unit 110 for supplying the under cover 10 to the mold of the rear injection machine to melt the synthetic resin made of PE, PP, PET, or GP to insert the rear insert reinforcement 100 and the additional injection unit 110, Forming step S50; Wherein the rear cover is formed of a resin material.

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