Electronic expansion valve, glass fiber reinforced nylon material and preparation method of glass fiber reinforced nylon material

Abstract

The invention discloses an electronic expansion valve, a glass fiber reinforced nylon material and a preparation method thereof, and the glass fiber reinforced nylon material at least comprises the following components: PA66 with the weight ratio of greater than or equal to 46%, the weight ratio of less than or equal to 58% and the viscosity of less than or equal to 2.2; pA6, the weight ratio of which is greater than or equal to 15% and less than or equal to 20%, and the viscosity of which is less than or equal to 2.0; the weight ratio of the glass fiber is greater than or equal to 20%, and the weight ratio is less than or equal to 40%; and the weight ratio of the flow modifier is greater than or equal to 0.05%. According to the scheme, the melt index of the glass fiber reinforced nylon material can be greater than or equal to 60g / 10min by reasonably constructing the addition amounts of the PA66, the PA6, the glass fiber and the flow modifier, and the flow property of the material can be greatly improved. Therefore, during injection molding, the glass fiber reinforced nylon material is more easily filled in the inner cavity of the mold, and the insert is not easy to deform due to compression during insert injection molding, so that the quality of an injection molding product can be improved.

Description

Technical Field

[0001] This invention relates to the field of nylon materials technology, specifically to an electronic expansion valve, a glass fiber reinforced nylon material, and a method for preparing the same. Background Technology

[0002] Glass fiber reinforced nylon is a plastic made by adding a certain amount of glass fiber to nylon resin for reinforcement. Compared with pure nylon, glass fiber reinforced nylon has significantly improved mechanical strength, rigidity, heat resistance, creep resistance, and fatigue strength. It can be widely used in injection molding of products, such as injection molding of valve bodies in electronic expansion valves and injection molding of coil encapsulation (insert injection molding).

[0003] However, due to formulation issues, existing glass fiber reinforced nylon materials often cannot be fully filled during injection molding, which affects the quality of injection molded products. Summary of the Invention

[0004] The purpose of this invention is to provide an electronic expansion valve, a glass fiber reinforced nylon material, and a method for preparing the same. The glass fiber reinforced nylon material has good flow properties, which can improve the quality of injection molded products.

[0005] To solve the above-mentioned technical problems, the present invention provides a glass fiber reinforced nylon material, comprising at least the following components: PA66, with a weight ratio ≥46% and a weight ratio ≤58%, and a viscosity ≤2.2; PA6, with a weight ratio ≥15% and a weight ratio ≤20%, and a viscosity ≤2.0; glass fiber, with a weight ratio ≥20% and a weight ratio ≤40%; and a flow modifier, with a weight ratio ≥0.05%.

[0006] In the above scheme, by reasonably configuring the addition amounts of PA66, PA6, glass fiber, and flow modifier, the melt index of the glass fiber reinforced nylon material can reach ≥60g / 10min, which can significantly improve the material's flow properties. Thus, during injection molding, the glass fiber reinforced nylon material is more easily filled into the mold cavity, and the inserts are less prone to deformation under pressure during insert injection molding, thereby improving the quality of the injection molded product.

[0007] Optionally, the weight ratio of the flow modifier is ≤0.15%.

[0008] Optionally, PA66 has a viscosity value of 2.2, and PA6 has a viscosity value of 2.0.

[0009] Optionally, the invention also includes additives, wherein the weight ratio of the additives is ≥0.05% and ≤2%.

[0010] Optionally, the additive is one or more of heat stabilizers, lubricants, and colorants.

[0011] Optionally, the heat stabilizer is a copper salt.

[0012] Optionally, the lubricant is a polyethylene wax.

[0013] Optionally, the glass fiber is chopped glass fiber.

[0014] This invention also provides a method for preparing glass fiber reinforced nylon material, applicable to the preparation of the above-mentioned glass fiber reinforced nylon material. The preparation method includes the following steps: preparing a main material, the main material comprising PA66, PA6, the flow modifier, and the additives mixed in proportion; adding the main material into the extruder from the main feed port of the extruder; adding the glass fiber into the extruder from the side feed port of the extruder in proportion; and controlling the extruder to perform extrusion operations.

[0015] The present invention also provides an electronic expansion valve, comprising a valve core, a valve body, and an encapsulation portion, wherein the encapsulation portion is made of the aforementioned glass fiber reinforced nylon material, the valve body comprises a winding skeleton and a rotor, the rotor being tractively connected to the valve core, a coil being wound on the winding skeleton, and the encapsulation portion covering at least the outside of the coil. Attached Figure Description

[0016] Figure 1 A flowchart illustrating the preparation method of the glass fiber reinforced nylon material provided by this invention;

[0017] Figure 2 This is a schematic diagram of an electronic expansion valve structure provided by the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In the description of embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0020] As described in the background section, glass fiber reinforced nylon materials can be widely used in product injection molding, such as valve body injection molding of electronic expansion valves and coil encapsulation injection molding (insert injection molding). However, the melt index of conventional glass fiber reinforced nylon materials is generally below 20 g / 10min, resulting in severely insufficient fluidity. During injection molding, issues such as incomplete filling of the mold cavity and deformation of the insert under pressure can easily occur, thus affecting the yield of injection molded products.

[0021] The common solution in existing technologies is to adjust the mold to improve the flow properties of glass fiber reinforced nylon materials, thereby increasing product yield. However, mold modification is very costly, and the adjustment methods are not universally applicable to different injection molded products. This necessitates individual design modifications for various types of injection molds, resulting in a huge workload. Therefore, improving the flow properties of glass fiber reinforced nylon materials from the root cause has become a key focus for those skilled in the art.

[0022] Based on this, the present invention provides a glass fiber reinforced nylon material, which, by adjusting the material composition, achieves a melt flow index ≥60g / 10min, significantly improving the material's flow properties. Thus, during injection molding, the glass fiber reinforced nylon material is more easily filled into the mold cavity, and inserts are less prone to deformation under pressure during injection molding, thereby improving the quality of injection molded products and largely avoiding the problems of mold modifications, resulting in excessive costs and workload.

[0023] Specifically, the aforementioned glass fiber reinforced nylon material includes at least the following components: PA66, with a weight ratio ≥46% and a weight ratio ≤58%, and a viscosity ≤2.2; PA6, with a weight ratio ≥15% and a weight ratio ≤20%, and a viscosity ≤2.0; glass fiber, with a weight ratio ≥20% and a weight ratio ≤40%; and flow modifier, with a weight ratio ≥0.05%.

[0024] Both PA66 and PA6 are nylon materials. PA66, commonly known as Nylon 66, has polyhexamethylene adipamide as its monomer, while PA6, commonly known as Nylon 6, has caprolactam as its monomer. Their physical and chemical properties are quite similar, therefore, they can be well combined as the nylon matrix in glass fiber reinforced nylon materials. PA6 has a relatively lower melting point, while PA66 has a relatively higher melting point, higher hardness, and lower moisture absorption. Therefore, a higher proportion of PA66 can be used to ensure the mechanical properties of the glass fiber reinforced nylon material, while reducing the requirements for sealing and protection during production, thus simplifying the manufacturing process.

[0025] The viscosity of PA66 was chosen to be ≤2.2, and the viscosity of PA6 was chosen to be ≤2.0. This results in relatively low viscosities for both PA66 and PA6. When these two are combined to form a nylon matrix, the effect on suppressing the flow properties of the glass fiber reinforced nylon material is relatively weak, which is more conducive to ensuring the final flow properties of the glass fiber reinforced nylon material.

[0026] Furthermore, the viscosity of PA66 can be controlled to 2.2 and the viscosity of PA6 can be controlled to 2.0. This can alleviate the problem of excessively low viscosity of the nylon matrix, excessively strong flow properties of glass fiber reinforced nylon materials, and the resulting surface fiber floating problem.

[0027] Glass fiber is a key material for improving the mechanical properties of glass fiber reinforced nylon materials; the greater the amount of glass fiber added, the stronger the mechanical properties of the glass fiber reinforced nylon material. In this embodiment of the invention, the proportion of glass fiber is set between 20% and 40%, that is, ≥20% and ≤40%. This can better ensure the mechanical properties of the glass fiber reinforced nylon material, while also largely avoiding the impact on the flow properties of the glass fiber reinforced nylon material due to excessive glass fiber introduction, as well as the surface fiber floating problem caused by excessive glass fiber.

[0028] In some alternative implementations, chopped glass fibers can be used. The length of the chopped fibers is relatively short, typically less than 6 mm, because their size does not require excessive length. This allows for greater flexibility in production and makes them easier to obtain. Furthermore, chopped glass fibers possess excellent dry flow properties and wet dispersibility, which is highly advantageous for continuous feeding to ensure the continuity of glass fiber reinforced nylon material production. Simultaneously, it also helps ensure the uniform distribution of glass fibers within the glass fiber reinforced nylon material.

[0029] The addition of flow modifiers is mainly used to improve the flow properties of glass fiber reinforced nylon materials. In this embodiment of the invention, the amount of flow modifier added is specifically controlled to ≥0.05%, which can better improve the flow properties of glass fiber reinforced nylon materials, so that the melt index of glass fiber reinforced nylon materials can reach ≥60g / 10min, in order to ensure the yield of injection molded products.

[0030] The aforementioned flow modifiers can be, for example, plastic flow modifiers, such as the flow modifier (AF-21) produced by Guangzhou Hecheng Industrial Co., Ltd., or modified polyamide ester (SR-340) produced by Shaorui Chemical (Shanghai) Co., Ltd. The addition of flow modifiers not only improves the flow properties of glass fiber reinforced nylon materials but also disperses the glass fibers, significantly reducing the surface fiber floating problem and thus improving the surface quality and appearance of the product.

[0031] In some optional implementations, the weight ratio of the flow modifier can be ≤0.15%. This allows for control over the upper limit of the flow modifier's addition, largely avoiding excessive flowability of the glass fiber reinforced nylon material caused by excessive flow modifier addition, as well as problems such as injection molding venting difficulties and easy blockage of venting gaps. Furthermore, avoiding excessive flowability of the glass fiber reinforced nylon material also helps to improve surface fiber floating phenomena, which is of positive significance for ensuring product quality.

[0032] In some alternative implementations, the glass fiber reinforced nylon material may further include additives at a weight ratio of ≥0.05% and ≤2% to assist in the molding of the glass fiber reinforced nylon material. For example, the additives may be one or more of heat stabilizers, lubricants, and colorants.

[0033] Heat stabilizers can inhibit the oxidative decomposition of materials caused by high temperatures during processing, thereby maintaining the physical and chemical properties of the materials and helping to improve processing and production efficiency. In this embodiment of the invention, the heat stabilizer can be a copper salt, such as copper phthalocyanine, copper acetate, or titanium dioxide-coated copper particles. During the high-temperature processing of nylon, copper ions can form a stable oxide layer on its surface, which can inhibit the high-temperature decomposition of nylon, thereby enhancing the thermal stability of the nylon material and extending its service life.

[0034] Lubricants help prevent thermal degradation of nylon caused by excessive heat generated by friction, and can also reduce melt viscosity and promote melt flowability. This is also beneficial in solving the surface fiber floating problem of glass fiber reinforced nylon materials, thereby improving the surface gloss of the product and enhancing its appearance. In this embodiment of the invention, the lubricant can be a polyethylene wax, which acts as an internal lubricant. Within the compound, it reduces intermolecular cohesive forces, thereby improving the internal frictional heat generation and flow properties of the glass fiber reinforced nylon material.

[0035] Based on material properties, colorants can include color powder, color masterbatch, color paste, and color oil, among which color powder is a powdered colorant, color masterbatch is a solid colorant, color paste is a paste-like colorant, and color oil is a liquid colorant. In practical applications, the appropriate colorant can be selected based on the specific needs. Based on material type, colorants can be organic materials, inorganic materials, or a combination of both.

[0036] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating the preparation method of the glass fiber reinforced nylon material provided by the present invention.

[0037] This invention also provides a method for preparing glass fiber reinforced nylon materials, applicable to the preparation of glass fiber reinforced nylon materials involved in the above-mentioned implementations. The preparation process is specifically achieved through an extruder, for example, a twin-screw extruder, which may include a main feed port and a side feed port. Figure 1 As shown, the preparation method may include the following steps S1 to S4.

[0038] Step S1: Prepare the main material, which includes PA66, PA6, and a flow modifier mixed in proportion. It should be understood that the aforementioned additives or other forms of additives may also be mixed into the main material, such as mold release agents.

[0039] The above step S1 can be performed inside a mixer. Alternatively, it can be done manually, either on the ground or in equipment such as hoppers.

[0040] Step S2 involves adding the main material into the extruder through the main feed port. When step S1 is performed in the mixer, the outlet of the mixer can be directly connected to the main feed port of the extruder. In this way, the main material after mixing can be directly discharged from the mixer into the main feed port of the extruder, which is more conducive to ensuring the continuity of production and the level of automation.

[0041] Step S3: Add glass fiber into the extruder from the side feed port of the extruder according to the proportion.

[0042] Step S4: Control the extruder to perform the extrusion operation. Thus, through melt blending and granulation in the extruder, the glass fiber reinforced nylon material required in the embodiments of the present invention can be obtained.

[0043] In practical applications, the glass fiber reinforced nylon materials involved in the above-mentioned implementation methods can be used to prepare various types of injection molded products. Based on the excellent flow properties of this glass fiber reinforced nylon material, issues such as incomplete filling of the mold cavity and deformation of inserts under pressure can be largely avoided when using this glass fiber reinforced nylon material for injection molding, thus ensuring a high product yield.

[0044] In specific injection molding processes, certain injection molding techniques can be combined to further improve product yield. For example, injection pressure and speed can be controlled to employ low-pressure, low-speed injection molding, thereby better ensuring the flow of glass fiber reinforced nylon material within the mold cavity. The aforementioned injection pressure can be controlled, for example, to 80 bar.

[0045] The aforementioned injection-molded products can be, for example, structural components such as valve bodies and valve seats of electronic expansion valves. Alternatively, they can be coil assemblies of electronic expansion valves, which include coils and encapsulation portions. In specific injection molding, the coil in the coil assembly can be used as an insert for insert injection molding, and then the encapsulation portion can be formed by injection molding on the coil.

[0046] In some embodiments, combined with Figure 2 The content is a schematic diagram of an electronic expansion valve structure shown in this invention, including a valve core 1, a valve body 2 and an encapsulation part 3. The valve body 2 includes a winding frame 21 and a rotor 22. The rotor 22 is connected to the valve core 1 in a driving manner. A coil 23 is provided on the winding frame 21. The encapsulation part 3 covers at least the outside of the coil 23. The coil 23 is encapsulated and fastened to the winding frame 21 by injection molding pressure, thereby reducing the risk of the coil 23 being exposed.

[0047] To better illustrate the formulation and performance of the glass fiber reinforced nylon material provided by this invention, the following will also compare several sets of specific data, with the injection molded product being a coil assembly as an example.

[0048] Table 1. Comparison of Components and Properties of Glass Fiber Reinforced Nylon Materials

[0049] As shown in Table 1 above, the conventional solution is usually the solution in Comparative Example 1. The viscosity of PA66 used is 2.7 and the viscosity of PA6 used is 2.4. Its fluidity is very low, and the melt index is only 12.7 g / 10min. When using the glass fiber reinforced nylon material in Comparative Example 1 to produce coil components, it is difficult to fill the inner wall of the coil, and the coil is also prone to deformation under pressure.

[0050] To address this, the applicant designed Comparative Example 2, Comparative Example 3, and Comparative Example 4 to gradually reduce the viscosity values ​​of PA66 and PA6. During this process, the melt index of the obtained glass fiber reinforced nylon material increased, and the flow properties were improved. However, for injection-molded products with inserts, such as coil assemblies, there were still problems such as the coil inner wall not being fully filled and the coil being prone to deformation. The quality of the injection-molded products was still difficult to meet the requirements.

[0051] Based on this, the applicant selected the viscosity values ​​of PA66 and PA6 in Comparative Example 4, specifically PA66 with a viscosity value of 2.2 and PA with a viscosity value of 2.0. Then, a flow modifier was added to the formulation, resulting in Examples 1, 2, and 3 in Table 1 above. The results showed that adding the flow modifier at amounts of 0.05, 0.1, and 0.15 all increased the melt index of the glass fiber reinforced nylon material to over 60 g / 10 min, significantly improving its flow properties. This effectively eliminated issues such as incomplete filling of the coil inner wall and coil deformation during coil assembly preparation, ensuring high product quality.

[0052] Furthermore, as can be seen from the data in Examples 1, 2, and 3, even with an increase in the proportion of glass fiber, the melt flow index can still be above 60 g / 10 min as the amount of flow modifier added increases, which fully meets the requirements for flow performance. Moreover, as in Example 3, increasing the glass fiber content to 40% allows for a relatively large glass fiber content, which is significant for ensuring the mechanical properties of glass fiber reinforced nylon materials.

[0053] Table 2 Comparison of Components and Properties of Glass Fiber Reinforced Nylon Materials

[0054] As shown in Table 2 above, the applicant also added Comparative Example 5, Comparative Example 6, Comparative Example 7, Example 4, and Example 5.

[0055] In conjunction with Example 2 and Comparative Example 5, when the flow modifier was reduced to 0.03, the melt index of the glass fiber reinforced nylon material dropped below 60%, resulting in poor flow properties. The undesirable phenomena of incomplete filling of the coil inner wall and coil deformation still occurred. Therefore, adding too little flow modifier is ineffective in the embodiments of this application.

[0056] In addition to Example 2 and Comparative Example 6, the amount of PA66 and PA6 added in Comparative Example 6 was greatly increased, and the amount of glass fiber added was reduced. Although this can meet the fluidity requirements and prevent the coil from being under-filled or deformed during injection molding, the amount of glass fiber added is too small, which will affect the mechanical properties of the injection molded product and will not meet the requirements for use.

[0057] In addition to Example 2 and Comparative Example 7, the amount of glass fiber added was increased to 45% in Comparative Example 7, and then the amount of PA66 and PA6 added was reduced. This resulted in a deterioration in flow performance, which again caused injection molding problems such as incomplete filling of the inner wall of the coil and coil deformation.

[0058] Combining Examples 2 and 4, when the flow modifier is increased to 0.18%, the melt index of the glass fiber reinforced nylon material increases to 69.3, and the flow properties are improved to a greater extent. During injection molding, it can meet the requirements of filling the inner wall of the coil and preventing coil deformation. However, surface fiber floating occurs, which still affects the performance of the glass fiber reinforced nylon material. Therefore, in a more preferred embodiment of the present invention, an upper limit needs to be set on the amount of flow modifier added to reduce the impact of excessively good flow properties on other aspects of the glass fiber reinforced nylon material's performance.

[0059] Combining Examples 2 and 5, when the viscosity of PA66 is adjusted to 2.0 and the viscosity of PA6 is adjusted to 1.8, the melt index of the glass fiber reinforced nylon material increases to 71.6, and the flow properties are improved to a greater extent. During injection molding, this meets the requirements of filling the inner wall of the coil and preventing coil deformation. However, surface fiber floating occurs, which still affects the performance of the glass fiber reinforced nylon material. Therefore, in a more preferred embodiment of the present invention, the viscosity of PA66 is set to 2.2 and the viscosity of PA6 is set to 2.0 to reduce the impact of excessively good flow properties on other properties of the glass fiber reinforced nylon material.

[0060] It should be noted that although Examples 4 and 5 are slightly inferior to Example 2, Examples 4 and 5 are also among the solutions claimed by this invention.

[0061] Analysis of the above five embodiments and seven comparative examples shows that in the embodiments of the present invention, there is a synergistic relationship between the content of PA66, the viscosity of PA66, the content of PA6, the viscosity of PA6, the content of glass fiber, and the content of flow modifier. Simply increasing the content of a single component may not be able to fully achieve the technical effect required by the embodiments of the present invention. Therefore, the limitations on each component in the embodiments of the present invention are reasonable.

[0062] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A glass fiber reinforced nylon material, characterized in that, It includes at least the following components: PA66, with a weight ratio ≥46% and a weight ratio ≤58%, and a viscosity ≤2.2; PA6, with a weight ratio ≥15% and a weight ratio ≤20%, and a viscosity ≤2.0; Glass fiber, with a weight ratio of ≥20% and ≤40%; Flow modifier, with a weight ratio ≥0.05%.

2. The glass fiber reinforced nylon material according to claim 1, characterized in that, The weight ratio of the flow modifier is ≤0.15%.

3. The glass fiber reinforced nylon material according to claim 1, characterized in that, The viscosity value of PA66 is 2.2, and the viscosity value of PA6 is 2.

0.

4. The glass fiber reinforced nylon material according to any one of claims 1-3, characterized in that, It also includes additives, wherein the weight ratio of the additives is ≥0.05% and the weight ratio of the additives is ≤2%.

5. The glass fiber reinforced nylon material according to claim 4, characterized in that, The additive is one or more of heat stabilizers, lubricants, and colorants.

6. The glass fiber reinforced nylon material according to claim 5, characterized in that, The heat stabilizer is a copper salt.

7. The glass fiber reinforced nylon material according to claim 5, characterized in that, The lubricant is a polyethylene wax.

8. The glass fiber reinforced nylon material according to any one of claims 1-3, characterized in that, The glass fiber is chopped glass fiber.

9. A method for preparing a glass fiber reinforced nylon material, characterized in that, The method applicable to the preparation of the glass fiber reinforced nylon material according to any one of claims 1-8 comprises the following steps: Prepare the main material, which includes PA66, PA6 and the flow modifier mixed in proportion; The main material is added to the extruder from the main feed port of the extruder; The glass fiber is added to the extruder from the side feed port of the extruder in proportion; Control the extruder to perform the extrusion operation.

10. An electronic expansion valve, characterized in that, The valve includes a valve core, a valve body, and an encapsulation portion. The encapsulation portion is made of glass fiber reinforced nylon material as described in any one of claims 1-8. The valve body includes a winding skeleton and a rotor. The rotor is throttle-connected to the valve core. A coil is wound on the winding skeleton. The encapsulation portion covers at least the outside of the coil.

Images