Polyimide profile and preparation method thereof

Abstract

The invention provides a polyimide profile and a preparation method thereof, and the preparation method comprises the following steps: adding polyimide resin powder into a mold of a molding press, and carrying out heat preservation on the polyimide resin powder at a preheating temperature; the preheating temperature is 200-230 DEG C; the upper pressing plate of the mold is put into the mold, pressure is applied to the polyimide resin powder in stages, the pressure is maintained for 3-5 s after pressure is applied in each stage, the pressure applied in stages is adjusted from low to high, and the pressure applying process in stages is repeated for multiple times; the polyimide resin powder is subjected to pressure maintaining under the mold pressing pressure, meanwhile, the mold is heated to the mold pressing temperature, and heat preservation and pressure maintaining treatment is conducted on the polyimide resin powder under the mold pressing temperature and the mold pressing pressure; after the heat and pressure preservation treatment is completed, cooling and demolding are conducted, and the polyimide profile is obtained. The preheating temperature of the polyimide resin powder in the mold press mold is controlled, and the polyimide resin powder in the mold is subjected to staged pressing operation before the mold is heated to the mold pressing temperature, so that polyimide resin is completely plasticized, exhaust is thorough, and the prepared polyimide profile is uniform in appearance color and high in yield. The impact strength is 280 kJ / m < 2 > or above, and the performance is better.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material molding, and more specifically, relates to a polyimide profile and a preparation method thereof. Background Art

[0002] Polyimide resins are widely used in demanding electrical insulation, heat insulation and wear resistance fields such as aerospace components, semiconductor processing, automobile manufacturing and energy production due to their excellent temperature resistance, insulation and mechanical properties.

[0003] Polyimide profiles are generally prepared by molding, but conventional molding processes usually result in incomplete plasticization of the polyimide profiles, uneven profile surface color, and poor mechanical properties. Summary of the invention

[0004] In view of the defects of the molding process in the prior art: incomplete exhaust, incomplete plasticization, and uneven profile surface during the molding process, which lead to poor material performance, the purpose of the present invention is to provide a polyimide profile and a preparation method thereof. The method solves the problems of uneven material color and poor performance caused by incomplete exhaust and the like by optimizing the exhaust process. The polyimide profile prepared by the present invention has uniform appearance color and better performance.

[0005] To achieve the above object, the first aspect of the present invention provides a method for preparing a polyimide profile, comprising the following steps:

[0006] Adding polyimide resin powder into a mold of a molding machine, and keeping the polyimide resin powder warm at a preheating temperature of 200-230° C.;

[0007] The upper pressing plate of the mold is placed into the mold, and the polyimide resin powder is pressed in stages, and the pressure is maintained for 3-5 seconds after each stage of pressing. The pressure of the staged pressing is adjusted from low to high, and the staged pressing process is repeated multiple times;

[0008] The polyimide resin powder is maintained under a molding pressure, and the mold is heated to a molding temperature, so that the polyimide resin powder is maintained under the molding temperature and the molding pressure;

[0009] After the heat preservation and pressure preservation treatment is completed, the temperature is reduced and the mold is demoulded to obtain a polyimide profile.

[0010] Furthermore, the stepwise pressure application includes the following steps:

[0011] The pressure increases from 0 to the first pressure and is maintained for 3-5 seconds; then it increases to the second pressure and is maintained for 3-5 seconds; then it increases to the third pressure and is maintained for 3-5 seconds; then it increases to the fourth pressure and is maintained for 3-5 seconds; finally it increases to the fifth pressure and is maintained for 3-5 seconds.

[0012] Furthermore, the pressure difference between two adjacent stages is 25-35 kg / cm 2 .

[0013] Furthermore, the fifth pressure is 150-160 kg / cm 2 .

[0014] Furthermore, the staged pressure application process is repeated 8-12 times.

[0015] Furthermore, the molding pressure is 50-70 kg / cm 2 .

[0016] Furthermore, the molding temperature is 360-390°C.

[0017] Furthermore, the heat preservation and pressure preservation treatment time is 30-50 minutes.

[0018] Furthermore, the cooling temperature during the cooling and demoulding is 200-230°C.

[0019] A second aspect of the present invention provides a polyimide profile, which is prepared by any of the preparation methods described above.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] The preparation method of the polyimide profile of the present invention controls the preheating temperature of the polyimide resin powder in the mold of the molding machine, and performs a staged pressurization operation on the polyimide resin powder in the mold before heating the mold to the molding temperature, so that the polyimide resin is completely plasticized and exhausted thoroughly, and the prepared polyimide profile has a uniform appearance color and an impact strength of 280 kJ / m 2 Above, the performance is better.

[0022] The polyimide profile prepared by the invention has uniform appearance color and an impact strength of more than 280 kJ / m2. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0025] The weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass described in the description of the embodiments of the present invention may be μg, mg, g, kg, or other mass units known in the biochemical field.

[0026] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. For example, without departing from the scope of the embodiments of the present invention, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0027] The embodiment of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0028] (1) adding polyimide resin powder into a mold of a molding machine and keeping the polyimide resin powder at a preheating temperature of 200-230° C.;

[0029] (2) placing the upper pressing plate of the mold into the mold, applying pressure to the polyimide resin powder in stages, maintaining the pressure for 3-5 seconds after each stage of pressure application, adjusting the pressure of the staged pressure application from low to high, and repeating the staged pressure application process multiple times;

[0030] (3) maintaining the polyimide resin powder under the molding pressure, and at the same time raising the temperature of the mold to the molding temperature, so that the polyimide resin powder is maintained at the molding temperature and the molding pressure;

[0031] (4) After the heat preservation and pressure preservation treatment is completed, the temperature is lowered and the mold is demoulded to obtain a polyimide profile.

[0032] In the above step (1), the embodiment of the present invention controls the preheating temperature of the polyimide resin powder to be 200-230° C., so that the polyimide resin powder can still remain in a powder state during the subsequent staged pressing process, so that the gas in the polyimide resin powder can be better discharged through the staged pressing, and avoid the preheating temperature being too high, causing part of the polyimide resin powder to be plasticized, resulting in subsequent difficulty in exhausting or incomplete exhausting, thereby affecting the performance of the prepared polyimide profile.

[0033] Specifically, the mold cavity specifications of the embodiment of the present invention are 100×100×60 mm, the molding machine is a 200T hydraulic molding machine, the release agent is a high-temperature release agent, and the polyimide resin powder is YS20.

[0034] In the above step (2), the embodiment of the present invention adopts staged pressure application and controls the holding time of each stage to exhaust the polyimide resin powder, so as to better exhaust the gas in the polyimide resin powder and improve the performance of the prepared polyimide profile. Conventional one-stage exhaust or two-stage exhaust cannot fully exhaust the gas in the polyimide resin powder, resulting in the surface of the prepared polyimide profile being yellow and opaque, and the impact strength is also low.

[0035] Furthermore, the staged pressure application in the embodiment of the present invention includes the following steps:

[0036] The pressure is increased from 0 to the first pressure, and maintained for 3-5 seconds; then increased to the second pressure, and maintained for 3-5 seconds; then increased to the third pressure, and maintained for 3-5 seconds; then increased to the fourth pressure, and maintained for 3-5 seconds; finally increased to the fifth pressure, and maintained for 3-5 seconds. Preferably, the pressure difference between two adjacent stages is 25-35 kg / cm 2 Specifically, the pressure in the embodiment of the present invention starts from 0 and increases by 30 kg / cm 2 A boost stage.

[0037] In the embodiment of the present invention, the fifth pressure is 150-160 kg / cm 2 , that is, the maximum boost pressure is 150-160kg / cm 2 .

[0038] In the embodiment of the present invention, the staged pressurization process is repeated 8-12 times to achieve a good exhaust effect and prepare a polyimide profile with uniform appearance and good impact strength performance.

[0039] In the above step (3), the molding pressure of the embodiment of the present invention is 50-70kg / cm 2 The molding temperature is 360-390℃, and the heat preservation and pressure treatment time is 30-50min.

[0040] In the above step (4), the cooling temperature during demoulding in the embodiment of the present invention is 200-230°C.

[0041] A method for preparing a polyimide profile according to an embodiment of the present invention controls the preheating temperature of the polyimide resin powder in the mold of the molding machine, and performs a staged pressurization operation on the polyimide resin powder in the mold before heating the mold to the molding temperature, so that the polyimide resin is completely plasticized and exhausted thoroughly, and the prepared polyimide profile has a uniform appearance and color, and an impact strength of 280 kJ / m 2 Above, the performance is better.

[0042] A polyimide profile and a preparation method thereof according to an embodiment of the present invention are described below by means of a plurality of specific embodiments.

[0043] Example 1

[0044] Embodiment 1 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0045] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30min. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 30kg / cm 2 , stay for 5s; then increase the pressure to 60kg / cm 2 , stay for 5s; raise the pressure to 90kg / cm 2 , stay for 5s; raise the pressure to 120kg / cm 2 , stay for 5s; raise the pressure to 150kg / cm 2 , stay for 5s; then release the pressure and repeat the above-mentioned step-by-step pressure increase steps, repeat 10 times in total, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 380℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 40 minutes. After the insulation and pressure are completed, cool it to 200℃ with air cooling, and then demoulding can be carried out.

[0046] Example 2

[0047] Embodiment 2 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0048] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30min. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 30kg / cm 2, stay for 5s; then increase the pressure to 60kg / cm 2 , stay for 5s; raise the pressure to 90kg / cm 2 , stay for 5s; raise the pressure to 120kg / cm 2 , stay for 5s; raise the pressure to 150kg / cm 2 , stay for 5s; then release the pressure and repeat the above-mentioned step-by-step pressure increase steps, repeat 10 times in total, and then set the molding pressure to 60kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 390℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 50 minutes. After the insulation and pressure are completed, cool it to 220℃ with air cooling, and then you can demould.

[0049] Example 3

[0050] Embodiment 3 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0051] Place the mold on the heating platform of the molding machine, set the preheating temperature to 220℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30 minutes. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 30kg / cm 2 , stay for 5s; then increase the pressure to 60kg / cm 2 , stay for 5s; raise the pressure to 90kg / cm 2 , stay for 5s; raise the pressure to 120kg / cm 2 , stay for 5s; raise the pressure to 150kg / cm 2 , stay for 5s; then release the pressure and repeat the above-mentioned step-by-step pressure increase steps, repeat 9 times in total, and then set the molding pressure to 70kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 370℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 30 minutes. After the insulation and pressure are completed, cool it to 200℃ with air cooling and then demoulding can be carried out.

[0052] Example 4

[0053] Embodiment 4 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0054] Place the mold on the heating platform of the molding machine, set the preheating temperature to 230℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30 minutes. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 30kg / cm 2 , stay for 5s; then increase the pressure to 60kg / cm2 , stay for 5s; raise the pressure to 90kg / cm 2 , stay for 5s; raise the pressure to 120kg / cm 2 , stay for 5s; raise the pressure to 150kg / cm 2 , stay for 5s; then release the pressure and repeat the above-mentioned step-by-step pressure increase steps, repeat 12 times in total, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 360℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 50 minutes. After the insulation and pressure are completed, cool it to 210℃ with air cooling, and then demolding can be carried out.

[0055] Comparative Example 1

[0056] Comparative Example 1 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0057] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30min. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 30kg / cm 2 ; Then increase the pressure to 60kg / cm 2 ; Raise the pressure to 90kg / cm 2 ; Raise the pressure to 120kg / cm 2 ; Raise the pressure to 150kg / cm 2 Then release the pressure and repeat the above-mentioned step-by-step pressure increase steps for 10 times, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 380℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 40 minutes. After the insulation and pressure are completed, cool it to 200℃ with air cooling, and then demoulding can be carried out.

[0058] Comparative Example 2

[0059] Comparative Example 2 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0060] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30min. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 30kg / cm 2 , stay for 5s; then increase the pressure to 60kg / cm 2 , stay for 5s; raise the pressure to 90kg / cm 2, stay for 5s; raise the pressure to 120kg / cm 2 , stay for 5s; raise the pressure to 150kg / cm 2 , stay for 5s; then release the pressure and repeat the above-mentioned step-by-step pressure increase steps, repeat 6 times in total, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 380℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 40 minutes. After the insulation and pressure are completed, cool it to 200℃ with air cooling, and then demoulding can be carried out.

[0061] Comparative Example 3

[0062] Comparative Example 3 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0063] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30 minutes. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 150kg / cm 2 , stay for 25s; then release the pressure and repeat the above pressure increase steps, repeat 10 times in total, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 380℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 40 minutes. After the insulation and pressure are completed, cool it to 200℃ with air cooling, and then demoulding can be carried out.

[0064] Comparative Example 4

[0065] Comparative Example 4 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0066] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30min. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, set the molding temperature to 380℃, heat up, and after reaching the molding temperature, then increase the pressure to 30kg / cm 2 , stay for 5s; then increase the pressure to 60kg / cm 2 , stay for 5s; raise the pressure to 90kg / cm 2 , stay for 5s; raise the pressure to 120kg / cm 2 , stay for 5s; raise the pressure to 150kg / cm 2 , stay for 5s; then release the pressure and repeat the above-mentioned step-by-step pressure increase steps, repeat 10 times in total, and then set the molding pressure to 50kg / cm 2, and maintain pressure for 40 minutes. After the heat preservation and pressure maintenance, air cool to 200℃ and then demould.

[0067] Comparative Example 5

[0068] Comparative Example 5 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0069] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30 minutes. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 60kg / cm 2 , stay for 10s; then increase the pressure to 150kg / cm 2 , stay for 15s; then release the pressure and repeat the above two-stage pressure increase steps, repeat 10 times in total, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 380℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 40 minutes. After the insulation and pressure are completed, cool it down to 200℃ with air cooling, and then demoulding can be carried out.

[0070] Comparative Example 6

[0071] Comparative Example 6 of the present invention provides a polyimide profile and a preparation method thereof, comprising the following steps:

[0072] Place the mold on the heating platform of the molding machine, set the preheating temperature to 200℃, heat up, and after reaching the preheating temperature, apply a release agent, then add 55.2g of YS20 polyimide resin powder, and keep it warm at the preheating temperature for 30 minutes. After the insulation is completed, place the upper pressing plate of the mold into the mold cavity, and then increase the pressure to 60kg / cm 2 , stay for 10s; then increase the pressure to 90kg / cm 2 , stay for 5s; then increase the pressure to 150kg / cm 2 , stay for 10 seconds; then release the pressure and repeat the above three-stage pressure increase steps, repeat 10 times in total, and then set the molding pressure to 50kg / cm 2 , and maintain the pressure. At the same time, set the molding temperature to 380℃, increase the temperature, and after reaching the molding temperature, keep the temperature and pressure for 40 minutes. After the insulation and pressure are completed, cool it down to 200℃ with air cooling, and then demoulding can be carried out.

[0073] The polyimide profiles obtained in the above Examples 1-4 and Comparative Examples 1-6 were subjected to appearance inspection and impact strength test. The performance comparison is shown in Table 1.

[0074] Table 1

[0075] Appearance <![CDATA[Impact strength (kJ / m 2 )]]> Example 1 Transparent, uniform amber color 285 Example 2 Transparent, uniform amber color 286 Example 3 Transparent, uniform amber color 289 Example 4 Transparent, uniform amber color 287 Comparative Example 1 Yellow surface, opaque 255 Comparative Example 2 Yellow surface, opaque 254 Comparative Example 3 Yellow surface, opaque 249 Comparative Example 4 Yellow surface, opaque 242 Comparative Example 5 Yellow surface, opaque 251 Comparative Example 6 Yellow surface, opaque 253

[0076] From the test results in Table 1, it can be seen that the preparation methods of Examples 1-4 of the present invention control the preheating temperature of the polyimide resin powder in the mold of the molding machine, and perform a staged pressurization operation on the polyimide resin powder in the mold before heating the mold to the molding temperature, and control the holding time of each stage, so that the polyimide resin is completely plasticized and exhausted thoroughly, and the prepared polyimide profiles have a transparent appearance, a uniform amber color, and an impact strength of 280 kJ / m 2 As shown above, compared with the comparative example, the impact strength can be increased by 19.4% at most.

[0077] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the attached claims.

Claims

1. A method for preparing a polyimide profile, characterized in that: The following steps are involved: Adding polyimide resin powder into a mold of a molding machine, and keeping the polyimide resin powder warm at a preheating temperature of 200-230° C.; The upper pressing plate of the mold is placed into the mold, and the polyimide resin powder is pressed in stages, and the pressure is maintained for 3-5 seconds after each stage of pressing. The pressure of the staged pressing is adjusted from low to high, and the staged pressing process is repeated multiple times; The polyimide resin powder is maintained under a molding pressure, and the mold is heated to a molding temperature, so that the polyimide resin powder is maintained under the molding temperature and the molding pressure; After the heat preservation and pressure preservation treatment is completed, the temperature is reduced and the mold is demoulded to obtain a polyimide profile.

2. The method for preparing a polyimide profile according to claim 1, characterized in that: The staged pressure application includes the following steps: The pressure increases from 0 to the first pressure and is maintained for 3-5 seconds; then it increases to the second pressure and is maintained for 3-5 seconds; then it increases to the third pressure and is maintained for 3-5 seconds; then it increases to the fourth pressure and is maintained for 3-5 seconds; finally it increases to the fifth pressure and is maintained for 3-5 seconds.

3. The method for preparing a polyimide profile according to claim 2, characterized in that: The pressure difference between two adjacent stages is 25-35kg / cm 2 .

4. The method for preparing a polyimide profile according to claim 2, characterized in that: The fifth pressure is 150-160 kg / cm 2 .

5. The method for preparing a polyimide profile according to claim 1, characterized in that: The staged pressure application process is repeated 8-12 times.

6. The method for preparing a polyimide profile according to claim 1, characterized in that: The molding pressure is 50-70kg / cm 2 .

7. The method for preparing a polyimide profile according to claim 1, characterized in that: The molding temperature is 360-390°C.

8. The method for preparing a polyimide profile according to claim 1, characterized in that: The time of the heat preservation and pressure preservation treatment is 30-50 minutes.

9. A method for preparing a polyimide profile according to any one of claims 1 to 8, characterized in that: The cooling temperature during the cooling and demoulding is 200-230°C.

10. A polyimide profile, characterized in that: The method is prepared by any one of claims 1 to 9.