Large-size closed mold for foaming polyimide

Abstract

The utility model provides a large-size closed mold for foaming polyimide, which comprises an outer mold, an inner mold and an inner mold, a base is arranged below the inner mold, side plates are arranged on the periphery of the inner mold, and rollers are installed below the inner mold. The outer mold is closed, so that the foaming atmosphere can be conveniently controlled, the crust of the polyimide foaming material is reduced, and the production cost is reduced. In addition, the inner mold is separated from the outer mold, the inner mold is easily pushed out / pulled out through the rollers on the base of the inner mold, demolding operation can be carried out outside the outer mold, and the use efficiency of the closed outer mold is greatly improved. And the movable connection modes such as the hinge and the bearing enable the assembly of the large-size die to be simpler, and the safety coefficient is also greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to foaming process technical field, more particularly to a kind of for polyimide foaming large size closed mould. BACKGROUND

[0002] Polyimide foam material not only has excellent temperature resistance, flame retardant and other properties, also has outstanding wave-penetrating characteristics and light weight, flexibility and good resilience, easy to use, so it is the ideal foam material of aircraft, can be used for space shuttle bulkhead heat insulation, ship cabin, vehicle and other fields.

[0003] We find that open free foaming can cause foam material to be seriously skinned, seriously affect product quality control and production efficiency.When the foaming volume is very large, the volume of the mold should be made large, and the dead weight is also very large, which will cause the assembly difficulty of most of the current up-down type mold, the reduction of safety factor and other problems.And we find that filling small molecule solvent in closed mold and foaming can successfully reduce the skinning of polyimide foam and improve production efficiency.Therefore, a new, convenient to use closed foaming mold is needed to solve the problems of existing foam skinning, assembly difficulty and low safety factor. SUMMARY

[0004] The utility model discloses a kind of large size closed moulds for polyimide foaming, to solve the problem of the skinning of foam caused by open foaming mold in prior art, large size mold assembly difficulty and low safety factor.

[0005] To solve the above technical problems, the utility model adopts the following technical scheme: provide a kind of large size closed mould for polyimide foaming, it includes: outer mould, the mould body of its four around is fixed, and its two ends have door type structure;Inner mould, its lower portion has base, and its four around has openable side plate, and its lower portion is installed with roller.

[0006] The top surface of the mold body of the outer mold has one or several air vents.

[0007] Preferably, the air vent of the outer mold is connected with metal pipeline and valve.

[0008] The connection between the door type structure of the outer mold and the mold body includes one of hinge, bearing and guide rail.

[0009] The door type structure of the outer mold is kept horizontal with the inner bottom surface of the mold body after being opened.

[0010] The connection between the base and the side plate of the inner mold includes one of hinge and bearing.

[0011] The upper end of the side plate of the inner mold is connected and fixed by right-angle quick clamp.

[0012] The side plate of the inner mold can be opened by 180° rotation.

[0013] According to the large-size closed mold for polyimide foaming provided by the utility model, the outside mold is closed, various gas / liquid can be conveniently injected, the foaming atmosphere is controlled, the skin of the polyimide foaming material is reduced, and the production cost is reduced. In addition, by separating the inside mold from the outside mold, the inside mold can be pulled out of the outside mold after foaming and demolding operation is conducted, the use efficiency of the closed outside mold is greatly improved, and the production efficiency is further improved. Moreover, the dynamic connection mode of the hinge and the bearing makes the assembly of the large-size mold simpler, and the safety factor is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is an exploded schematic view of the large-size closed mold provided by the utility model. DETAILED DESCRIPTION

[0015] The utility model will be further described below in combination with specific embodiments. It should be understood that the following embodiments are only used for describing the utility model and are not used for limiting the scope of the utility model.

[0016] Combined with Figure 1 As shown in the figure, the large-size closed mold for polyimide foaming provided by the preferred embodiment of the utility model mainly comprises two parts of an outside mold 1 and an inside mold 2.

[0017] The outside mold 1 comprises a mold body 11 and a door type structure 12 at both ends. The mold body 11 and the door type structure 12 of the outside mold 1 are connected through a hinge 13. After the door type structure 12 of the outside mold 1 is opened, the inner bottom surface of the mold body 11 is kept horizontal.

[0018] The outside mold 1 further comprises a gas inlet hole 14, and the gas inlet hole 14 is connected with the outside through a metal pipeline 15 and a valve 16. The gas / liquid is injected into the mold through the gas inlet hole 14.

[0019] The bottom base 21 of the inside mold 2 is flat on the upper surface, and a roller 22 is installed below. The bottom base 21 and the side plate 23 of the inside mold 2 are connected through a hinge 24. The upper ends of the side plates 23 of the inside mold 2 are connected and fixed through right-angle quick clamps 25. The side plate 23 of the inside mold 2 can be opened by 180° rotation.

[0020] In actual use, the steps of manufacturing the polyimide large-size foaming material are as follows: step 51: the inside mold 2 is installed and fixed, and the polyimide before foaming is pressed flat and placed in the inside mold 2.

[0021] Step 52: heating the outer mold 1 to the foaming temperature of the foaming material, pushing the inner mold 2 into the outer mold 1, locking the door structure 12, opening the valve 16 to inject water vapor, and then closing the valve 16.

[0022] The foaming temperature and the steam pressure required for maintaining the foaming prepolymer are greater than or equal to 150 DEG C and less than or equal to 240 DEG C, and greater than or equal to 1000 psi and less than or equal to 3000 psi, for example.

[0023] Step 53: opening the valve 16, slowly releasing the pressure of the outer mold 1 to the atmospheric pressure, heating the outer mold 1 to the imidization temperature of the foaming material and maintaining for 3 hours.

[0024] Step 54: cooling to 150 DEG C, opening the door structure 12, pushing out the inner mold 2, and naturally cooling.

[0025] Step 55: opening the right-angle quick clamp 24, opening the side plate 23, demolding, and taking out the foaming material which has been formed.

[0026] According to the above description, the advantages of the embodiment can be summarized as follows:

[0027] I. By the closed structure of the outer mold 1, the added water vapor can reduce the viscosity of the surface of the foaming prepolymer, improve the flowability of the skin prepolymer material, thereby reducing the skinning of the polyimide in the foaming process, effectively reducing the production cost and improving the production efficiency.

[0028] II. The hinge 13 is connected between the mold body 11 of the outer mold 1 and the door structure 12, which effectively avoids the positioning problem in the assembly process, and makes the assembly more convenient. In addition, the connection of the hinge 13 makes one end of the door structure 12 fixed, and the operation is safer.

[0029] III. The roller 22 is arranged below the base 21 of the inner mold 2, which can greatly reduce the friction between the inner mold 2 and the outer mold 1, and the inner mold 2 can be easily pulled out or pushed out.

[0030] IV. The demolding operation of the foaming material from the inner mold 2 does not need to occupy the space of the outer mold 1, and the turnover speed of the outer mold 1 is improved.

[0031] In summary, the closed mold can indeed achieve the purpose of the present application.

[0032] The above merely describes preferred embodiments of the present application, and is not intended to limit the scope of the present application, and the above embodiments of the present application can be variously changed. Any simple, equivalent changes and modifications made according to the content of the claims and the specification of the present application are all within the scope of the claims of the present application. The present application is not described in detail, and is conventional technical content.

Claims

1. A large-size closed mold for polyimide foaming, characterized by, The utility model relates to a mould for casting, comprising: an outer mould fixed around a mould body, with door type structure at both ends; an inner mould with a base at the bottom and openable side plates around the mould body, with roller wheels installed at the bottom.

2. The large size closed mold according to claim 1, wherein, The top surface of the mould body of the outer mould has one or several air holes.

3. The large size closed mold according to claim 2, wherein, The air holes of the outer mould are connected with metal pipes and valves.

4. The large size closed mold according to claim 1, wherein, The connection between the door type structure of the outer mould and the mould body comprises one of a hinge, a bearing and a guide rail.

5. The large size closed mold according to claim 1, wherein, The door type structure of the outer mould is kept horizontal with the inner bottom surface of the mould body after being opened.

6. The large size closed mold according to claim 1, wherein, The connection between the base and the side plates of the inner mould comprises one of a hinge and a bearing.

7. The large size closed mold according to claim 1, wherein The upper ends of the side plates of the inner mould are connected and fixed with each other through right-angle quick clamps.

8. The large size closed mold according to claim 1, wherein, The side plates of the inner mould can be rotated by 180 degrees to be opened.

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