Polybutylene terephthalate insulating gasket and preparation method thereof

Abstract

The present invention provides a polybutylene terephthalate (PBTE) insulating gasket and a method for preparing the same. The PBT insulating gasket is made from recycled mica board material and polybutylene terephthalate (PBTE). This invention, while recycling mica board waste as raw material for the PBT insulating gasket, provides a new approach to recycling mica board waste. Furthermore, the PBT insulating gasket produced by the present invention exhibits both excellent mechanical properties and heat resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of insulating gasket materials, and particularly relates to a polybutylene terephthalate insulating gasket and a preparation method thereof. Background Art

[0002] Mica-reinforced plastic sheets primarily include mica-reinforced epoxy resin sheets or mica-reinforced silicone resin sheets. Mica board composites are high-performance materials formed by coating a base material with mica paper in a specific ratio, then using a specialized mold and hot-pressing process. They offer advantages such as lightweight, high hardness, excellent insulation, high mechanical strength, and corrosion resistance. However, currently, there are very few methods for recycling them. With the annual increase in mica board production and usage, the amount of mica board scrap generated during production and the number of discarded mica board products has also increased year by year, leading to a growing concern among researchers regarding the disposal of mica board waste.

[0003] Mica boards have a very low glue content, generally less than 10%, making the corresponding waste disposal relatively difficult. Currently, the chemical recovery and energy recovery methods used in the methods disclosed in the existing technology for treating resin-based composite material waste are not suitable for mica board recycling. Moreover, chemical recovery and energy recovery have disadvantages such as high cost and large secondary pollution.

[0004] Currently, physical comminution methods and methods for reusing waste resin-based composite materials in composite materials are widely researched and widely adopted. For example, CN1554493A discloses a method for recycling fiberglass reinforced plastic waste, which is granulated into pellets for use as filler in sheet molding compound (SMC). However, the mechanical properties of the composite materials produced by this method have not been improved, and the products are still low-value, low-end resin-based composite materials, which still face disposal challenges after they are scrapped.

[0005] Polybutylene terephthalate (PBTE) insulating gaskets are widely used in the electronics, electrical machinery, and communications industries, providing insulation, wear resistance, protection, and light-shielding properties in various products. However, there are currently no reports on the recycling of mica board waste into polybutylene terephthalate (PBTE) insulating gaskets.

[0006] Therefore, in this field, there is an urgent need to develop a product and a preparation method for high-performance polybutylene terephthalate insulating gaskets prepared from mica board waste, so as to achieve efficient recycling of mica board waste. Summary of the Invention

[0007] To address the shortcomings of the prior art, the present invention provides a polybutylene terephthalate (PBTE) insulating gasket and a method for its preparation. This invention, on the one hand, recycles mica board waste as raw material for the PBTE insulating gasket, providing a new approach for recycling mica board waste. On the other hand, the PBTE insulating gasket produced by the present invention exhibits both excellent mechanical properties and heat resistance.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a polybutylene terephthalate insulating gasket, wherein the raw materials for preparing the polybutylene terephthalate insulating gasket are composed of recycled mica board material and polybutylene terephthalate.

[0010] It should be noted that the mica board recycled material in the present invention is obtained by recycling mica board waste, and the mica board waste includes scraps generated during the production of mica epoxy boards (products) and mica silicone boards (products), as well as various scrapped mica reinforced resin products.

[0011] The present invention utilizes waste mica boards to prepare polybutylene terephthalate (PBTE) insulating gaskets, providing a new approach for recycling mica board waste and, to a certain extent, resolving the difficulties, limited scope, and high energy consumption associated with the utilization of waste mica-reinforced resin products. Furthermore, the recycled mica board material contains a large amount of mica powder and a small amount of resin matrix powder, with the recycled mica board material containing more than 90% by weight of mica. The mica powder prepared by crushing waste mica boards exhibits improved compatibility with polybutylene terephthalate (PBTE) due to the presence of organic resin on its surface. The present invention incorporates the recycled mica board material into the insulating gasket, thereby increasing the mechanical strength and temperature resistance of the insulating gasket, ultimately resulting in an insulating gasket with excellent overall performance.

[0012] Preferably, based on the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the mass percentage of the recycled mica board material is 5-12.5%, preferably 6-8%, for example, it can be 5%, 6%, 7%, 7.5%, 8%, 9%, 10%, 11%, 12%, 12.5%, etc.

[0013] Preferably, based on the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the mass percentage of the polybutylene terephthalate is 87.5-95%, for example, it can be 87.5%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, etc.

[0014] Preferably, the recycled mica board material is a recycled mica board material that has been surface-treated with a silane coupling agent.

[0015] In the present invention, the recycled mica plate is surface-treated with a silane coupling agent to increase the compatibility of the mica with polybutylene terephthalate, thereby improving the performance of the product.

[0016] Preferably, the silane coupling agent includes any one of KH550 silane coupling agent, KH560 silane coupling agent or hexadecyltrimethoxysilane, or a combination of at least two thereof, preferably KH550 silane coupling agent.

[0017] Preferably, the particle size of the recycled mica board material is not higher than 106 μm, preferably less than 45 μm, for example, it can be 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 55 μm, 65 μm, 75 μm, 85 μm, 95 μm, 105 μm, etc.

[0018] Preferably, the model of the polybutylene terephthalate is DuPont PBT ST820.

[0019] In a second aspect, the present invention provides a method for preparing the polybutylene terephthalate insulating gasket according to the first aspect, the method comprising the following steps:

[0020] Mica plate recycled material and polybutylene terephthalate are mixed to obtain a mixture; the mixture is sequentially extruded and molded to obtain the polybutylene terephthalate insulating gasket.

[0021] Preferably, the recycled mica board material is obtained by crushing and screening mica board waste.

[0022] In the present invention, the mica plate waste is cleaned, dried, crushed, and then sieved using standard sieves of 150 mesh, 200 mesh, and 325 mesh to obtain mica plate recycled materials.

[0023] Preferably, the recycled mica board material is a recycled mica board material that has been surface-treated with a silane coupling agent.

[0024] Preferably, the silane coupling agent includes any one of KH550 silane coupling agent, KH560 silane coupling agent or hexadecyltrimethoxysilane, or a combination of at least two thereof, preferably KH550 silane coupling agent.

[0025] Preferably, based on the total mass of the mica board recycled material and polybutylene terephthalate as 100%, the mass percentage of the mica board recycled material is 5-12.5%, preferably 6-8%, for example, it can be 5%, 6%, 7%, 7.5%, 8%, 9%, 10%, 11%, 12%, 12.5%, etc.

[0026] Preferably, based on the total mass of the mica board recycled material and polybutylene terephthalate as 100%, the mass percentage of the polybutylene terephthalate is 87.5-95%, for example, it can be 87.5%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, etc.

[0027] In the present invention, the recycled mica board material and polybutylene terephthalate are dried before mixing, for example, by drying at 80° C. for 2 hours.

[0028] Preferably, the extrusion equipment is a twin-screw extruder.

[0029] Preferably, the twin-screw extruder comprises a first zone, a second zone, a third zone and a fourth zone connected in sequence.

[0030] Preferably, the temperature of the first zone is 220°C, the temperature of the second zone is 230°C, the temperature of the third zone is 245°C, and the temperature of the fourth zone is 230°C.

[0031] Preferably, the extrusion further includes pelletizing.

[0032] Preferably, the molding process comprises an injection molding process.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a polybutylene terephthalate (PBTE) insulating gasket produced from mica board waste, providing a new approach for recycling mica board waste and, to a certain extent, resolving the difficulties, limited scope, and high energy consumption associated with the utilization of mica-reinforced resin product waste. Furthermore, the addition of crushed mica board waste enhances the mechanical strength and heat resistance of the insulating gasket, resulting in a polybutylene terephthalate (PBTE) insulating gasket with improved mechanical strength and superior mechanical and heat resistance.

[0035] The polybutylene terephthalate insulating gasket product prepared by the present invention has excellent performance and can be widely used in the fields of electronic appliances, motors, communications and the like.

[0036] The present invention adopts a simple process of extrusion granulation and injection molding, and has the advantages of short molding cycle, high production efficiency and excellent comprehensive performance of the product. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0038] Example 1

[0039] This embodiment provides a polybutylene terephthalate insulating gasket. Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the raw materials for preparing the polybutylene terephthalate insulating gasket are composed of 7.5% by mass of recycled mica board surface treated with KH550 type silane coupling agent and 92.5% by mass of polybutylene terephthalate (model DuPont PBT ST820).

[0040] This embodiment also provides a method for preparing the polybutylene terephthalate insulating gasket, which comprises the following steps:

[0041] The mica-reinforced epoxy resin board was cleaned, dried, and crushed, and then sieved with standard sieves of 150 mesh, 200 mesh, and 325 mesh to obtain mica board recycled materials with a particle size of less than 45 μm; a mixed solution of ethanol and deionized water with a mass ratio of 95:5 was prepared, and a KH550 silane coupling agent was added under stirring to a mass concentration of 2%, and the mixture was hydrolyzed for 2 hours before use. The recycled mica plate material with a particle size of less than 45 μm is soaked for 30 minutes, and the recycled mica plate material surface-treated with a KH550 silane coupling agent is obtained by filtering; the recycled mica plate material surface-treated with a KH550 silane coupling agent and polybutylene terephthalate are dried at 80° C. for 2 hours and then mixed according to a formula to obtain a mixture; the mixture is sequentially extruded, pelletized and injection molded, wherein a twin-screw extruder is used for extrusion, and the twin-screw extruder includes a first zone, a second zone, a third zone and a fourth zone connected in sequence, the temperature of the first zone is 220° C., the temperature of the second zone is 230° C., the temperature of the third zone is 245° C., and the temperature of the fourth zone is 230° C., to obtain the polybutylene terephthalate insulating gasket.

[0042] Example 2

[0043] This embodiment provides a polybutylene terephthalate insulating gasket. Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the raw materials for preparing the polybutylene terephthalate insulating gasket are composed of 6% by mass of recycled mica board surface-treated with KH550 type silane coupling agent and 94% by mass of polybutylene terephthalate (model DuPont PBT ST820).

[0044] This embodiment also provides a method for preparing the polybutylene terephthalate insulating gasket, which comprises the following steps:

[0045] The mica-reinforced epoxy resin board was cleaned, dried, and crushed, and then sieved with standard sieves of 150 mesh, 200 mesh, and 325 mesh to obtain mica board recycled materials with a particle size of less than 45 μm; a mixed solution of ethanol and deionized water with a mass ratio of 95:5 was prepared, and a KH550 silane coupling agent was added under stirring to a mass concentration of 2%, and the mixture was hydrolyzed for 2 hours before use. The recycled mica plate material with a particle size of less than 45 μm is soaked for 30 minutes, and the recycled mica plate material surface-treated with a KH550 silane coupling agent is obtained by filtering; the recycled mica plate material surface-treated with a KH550 silane coupling agent and polybutylene terephthalate are dried at 80° C. for 2 hours and then mixed according to a formula to obtain a mixture; the mixture is sequentially extruded, pelletized and injection molded, wherein a twin-screw extruder is used for extrusion, and the twin-screw extruder includes a first zone, a second zone, a third zone and a fourth zone connected in sequence, the temperature of the first zone is 220° C., the temperature of the second zone is 230° C., the temperature of the third zone is 245° C., and the temperature of the fourth zone is 230° C., to obtain the polybutylene terephthalate insulating gasket.

[0046] Example 3

[0047] This embodiment provides a polybutylene terephthalate insulating gasket. Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the raw materials for preparing the polybutylene terephthalate insulating gasket are composed of 8% by mass of recycled mica board surface treated with KH550 type silane coupling agent and 92% by mass of polybutylene terephthalate (model DuPont PBT ST820).

[0048] This embodiment also provides a method for preparing the polybutylene terephthalate insulating gasket, which comprises the following steps:

[0049] The mica-reinforced epoxy resin board was cleaned, dried, and crushed, and then sieved with standard sieves of 150 mesh, 200 mesh, and 325 mesh to obtain mica board recycled materials with a particle size of less than 45 μm; a mixed solution of ethanol and deionized water with a mass ratio of 95:5 was prepared, and a KH550 silane coupling agent was added under stirring to a mass concentration of 2%, and the mixture was hydrolyzed for 2 hours before use. The recycled mica plate material with a particle size of less than 45 μm is soaked for 30 minutes, and the recycled mica plate material surface-treated with a KH550 silane coupling agent is obtained by filtering; the recycled mica plate material surface-treated with a KH550 silane coupling agent and polybutylene terephthalate are dried at 80° C. for 2 hours and then mixed according to a formula to obtain a mixture; the mixture is sequentially extruded, pelletized and injection molded, wherein a twin-screw extruder is used for extrusion, and the twin-screw extruder includes a first zone, a second zone, a third zone and a fourth zone connected in sequence, the temperature of the first zone is 220° C., the temperature of the second zone is 230° C., the temperature of the third zone is 245° C., and the temperature of the fourth zone is 230° C., to obtain the polybutylene terephthalate insulating gasket.

[0050] Example 4

[0051] This embodiment provides a polybutylene terephthalate insulating gasket. Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the raw materials for preparing the polybutylene terephthalate insulating gasket are composed of 5% by mass of recycled mica board surface treated with KH550 type silane coupling agent and 95% by mass of polybutylene terephthalate (model DuPont PBT ST820).

[0052] This embodiment also provides a method for preparing the polybutylene terephthalate insulating gasket, which comprises the following steps:

[0053] The mica reinforced epoxy resin board is cleaned, dried, and crushed, and then sieved with standard sieves of 150 mesh, 200 mesh, and 325 mesh to obtain recycled mica board materials with a particle size of 45 μm-75 μm; the recycled mica board materials with a particle size of 45 μm-75 μm are mixed with a KH550 silane coupling agent solution, and a mixed solution is prepared by mixing ethanol and deionized water in a mass ratio of 95:5, and the KH550 silane coupling agent is added under stirring to make the mass concentration of the mixed solution 2%, and the mixed solution is hydrolyzed for 2 hours before use. The invention relates to a method for preparing a polybutylene terephthalate insulating gasket. The method comprises the following steps: soaking mica plate recycled material with a particle size of 45 μm-75 μm for 30 minutes, filtering to obtain mica plate recycled material surface-treated with a KH550 silane coupling agent; drying the mica plate recycled material surface-treated with a KH550 silane coupling agent and polybutylene terephthalate at 80° C. for 2 hours, and then mixing them according to a formula to obtain a mixture; extruding, pelletizing and injection molding the mixture in sequence, wherein a twin-screw extruder is used for extrusion, and the twin-screw extruder includes a first zone, a second zone, a third zone and a fourth zone connected in sequence, the temperature of the first zone is 220° C., the temperature of the second zone is 230° C., the temperature of the third zone is 245° C., and the temperature of the fourth zone is 230° C., to obtain the polybutylene terephthalate insulating gasket.

[0054] Example 5

[0055] This embodiment provides a polybutylene terephthalate insulating gasket. Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the raw materials for preparing the polybutylene terephthalate insulating gasket are composed of 12.5% ​​by mass of recycled mica board surface treated with KH550 type silane coupling agent and 87.5% by mass of polybutylene terephthalate (model DuPont PBT ST820).

[0056] This embodiment also provides a method for preparing the polybutylene terephthalate insulating gasket, which comprises the following steps:

[0057] The mica reinforced epoxy resin board is cleaned, dried, and crushed, and then sieved with standard sieves of 150 mesh, 200 mesh, and 325 mesh to obtain recycled mica board materials with a particle size of 45 μm-75 μm; the recycled mica board materials with a particle size of 45 μm-75 μm are mixed with a KH550 silane coupling agent solution, and a mixed solution is prepared by mixing ethanol and deionized water in a mass ratio of 95:5, and the KH550 silane coupling agent is added under stirring to make the mass concentration of the mixed solution 2%, and the mixed solution is hydrolyzed for 2 hours before use. The invention relates to a method for preparing a polybutylene terephthalate insulating gasket. The method comprises the following steps: soaking mica plate recycled material with a particle size of 45 μm-75 μm for 30 minutes, filtering to obtain mica plate recycled material surface-treated with a KH550 silane coupling agent; drying the mica plate recycled material surface-treated with a KH550 silane coupling agent and polybutylene terephthalate at 80° C. for 2 hours, and then mixing them according to a formula to obtain a mixture; extruding, pelletizing and injection molding the mixture in sequence, wherein a twin-screw extruder is used for extrusion, and the twin-screw extruder includes a first zone, a second zone, a third zone and a fourth zone connected in sequence, the temperature of the first zone is 220° C., the temperature of the second zone is 230° C., the temperature of the third zone is 245° C., and the temperature of the fourth zone is 230° C., to obtain the polybutylene terephthalate insulating gasket.

[0058] Example 6

[0059] The difference between this embodiment and embodiment 1 is that, based on the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket being 100%, the mass percentage of the mica board recycled material surface-treated with KH550 type silane coupling agent is 2%, and the rest is the same as embodiment 1.

[0060] Example 7

[0061] The difference between this embodiment and embodiment 1 is that, based on the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket being 100%, the mass percentage of the mica board recycled material surface-treated with KH550 type silane coupling agent is 20%, and the rest is the same as embodiment 1.

[0062] Example 8

[0063] The difference between this embodiment and embodiment 1 is that the recycled mica board material has not been surface treated with KH550 silane coupling agent, and the rest is the same as embodiment 1.

[0064] Example 9

[0065] The difference between this embodiment and embodiment 1 is that the particle size of the recycled mica board material is 150 μm, and the rest is the same as embodiment 1.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that the mica plate recycled material surface-treated with KH550 silane coupling agent is replaced with mica powder surface-treated with KH550 silane coupling agent of equal content, and the rest is the same as Example 1.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that the mica plate recycled material surface-treated with KH550 silane coupling agent is replaced with an equal amount of mica powder not surface-treated with KH550 silane coupling agent, and the rest is the same as Example 1.

[0070] Test conditions

[0071] The polybutylene terephthalate insulating gaskets provided in Examples 1 to 9 and Comparative Examples 1 to 2 were subjected to performance tests, and the test methods were as follows:

[0072] (1) Bending strength: The equipment uses a universal material testing machine, and the bending strength test of the insulating gasket is in accordance with GB / T9341-2008.

[0073] (2) Heat resistance test: Place an insulating gasket of 10 mm × 10 mm × 4 mm on a heating plate at 250°C, apply a pressure of 5 kg on the upper part of the insulating gasket, and test the time it takes for it to completely melt.

[0074] The test results are shown in Table 1:

[0075] Table 1

[0076] Flexural strength (MPa) Temperature resistance test(s) Example 1 88.81 190 Example 2 85.43 170 Example 3 87.55 190 Example 4 80.65 160 Example 5 85.91 180 Example 6 78.16 130 Example 7 80.90 150 Example 8 75.82 140 Example 9 77.35 154 Comparative Example 1 74.62 126 Comparative Example 2 72.40 110

[0077] As can be seen from Table 1, the present invention utilizes mica board waste to prepare polybutylene terephthalate (PBTE) insulating gaskets, providing a new approach for recycling mica board waste and, to a certain extent, resolving the difficulties, limited scope, and high energy consumption associated with the utilization of mica-reinforced resin product waste. Furthermore, the addition of crushed mica board waste enhances the mechanical strength and heat resistance of the insulating gaskets, resulting in improved mechanical strength and superior mechanical and heat resistance properties.

[0078] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A polybutylene terephthalate insulating gasket, characterized in that: The raw materials for preparing the polybutylene terephthalate insulating gasket are composed of recycled mica board and polybutylene terephthalate; the recycled mica board contains more than 90wt.% of mica; the raw materials for preparing the recycled mica board are mica-reinforced epoxy resin boards; and the particle size of the recycled mica board is not higher than 106μm; Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the mass percentage of the recycled mica board material is 5-12.5%.

2. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: Taking the total mass of the raw materials for preparing the polybutylene terephthalate insulating gasket as 100%, the mass percentage of the recycled mica board material is 6-8%.

3. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: The mica plate recycled material is a mica plate recycled material that has been surface-treated with a silane coupling agent.

4. The polybutylene terephthalate insulating gasket according to claim 3, characterized in that: The silane coupling agent includes any one of KH550 silane coupling agent, KH560 silane coupling agent or hexadecyltrimethoxysilane, or a combination of at least two thereof.

5. The polybutylene terephthalate insulating gasket according to claim 4, characterized in that: The silane coupling agent is KH550 type silane coupling agent.

6. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: The particle size of the recycled mica plate is less than 45 μm.

7. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: The density of the polybutylene terephthalate is 1.20-1.23 g / cm 3 .

8. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: The melt index of the polybutylene terephthalate is 5 g / 10 min.

9. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: The melting temperature of the polybutylene terephthalate is 225-250°C.

10. The polybutylene terephthalate insulating gasket according to claim 1, characterized in that: The processing melt temperature of the polybutylene terephthalate is 240-260°C.

11. A method for preparing a polybutylene terephthalate insulating gasket according to any one of claims 1 to 10, characterized in that: The method comprises the following steps: Mica plate recycled material and polybutylene terephthalate are mixed to obtain a mixture; the mixture is sequentially extruded and molded to obtain the polybutylene terephthalate insulating gasket.

12. The method according to claim 11, characterized in that The mica plate recycled material is obtained by crushing and screening mica plate waste.

13. The method according to claim 11, characterized in that The mica plate recycled material is a mica plate recycled material that has been surface-treated with a silane coupling agent.

14. The method according to claim 13, characterized in that The silane coupling agent includes any one of KH550 silane coupling agent, KH560 silane coupling agent or hexadecyltrimethoxysilane, or a combination of at least two thereof.

15. The method according to claim 14, characterized in that The silane coupling agent is KH550 type silane coupling agent.

16. The method according to claim 11, characterized in that Taking the total mass of the mica plate recycled material and polybutylene terephthalate as 100%, the mass percentage of the mica plate recycled material is 6-8%.

17. The method according to claim 11, characterized in that The extrusion equipment is a twin-screw extruder.

18. The method according to claim 17, characterized in that The twin-screw extruder comprises a first zone, a second zone, a third zone and a fourth zone which are connected in sequence.

19. The method according to claim 18, characterized in that The temperature of the first zone is 220°C, the temperature of the second zone is 230°C, the temperature of the third zone is 245°C, and the temperature of the fourth zone is 230°C.

20. The method according to claim 11, characterized in that The extrusion process also includes pelletizing.

21. The method according to claim 11, wherein The molding process includes an injection molding process.