Testing method and testing device for fluidity of glass fiber reinforced phenolic moulding plastic
By reading the time T from the start of melting to extrusion from the test mold gap in the glass fiber reinforced phenolic molding material in the fluidity test, the problem that existing testing methods cannot accurately evaluate the fluidity is solved, and higher testing accuracy and operation ease is achieved.
Patent Information
- Application Number
- CN202510149868.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-11
- Publication Date
- 2025-06-20
AI Technical Summary
The existing fluidity testing methods for glass fiber reinforced phenolic molding materials cannot accurately characterize the fluidity index of the material, and the test results are not accurate enough.
A test method is used to determine the fluidity by placing the test raw materials under normal temperature and humidity conditions, preheating the test mold using a hydraulic press, and reading the time T from the start of melting to the extrusion from the gap of the test mold under set pressure.
This method simplifies testing operations, improves the accuracy and operability of the test, and enables more efficient evaluation of the fluidity of glass fiber reinforced phenolic molding materials.
Smart Images
Figure CN120177290A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of thermosetting plastics, and in particular to a method and device for testing the fluidity of glass fiber reinforced phenolic molding compound. Background Art
[0002] Due to the superiority of specific strength, specific modulus, toughness, heat resistance, environmental resistance and processing performance, thermosetting glass fiber reinforced phenolic molding compound is applied to advanced scientific fields such as aerospace, automotive, sports, construction, medical and other fields. Fluidity is an important index to measure the molding quality of thermosetting glass fiber reinforced phenolic molding compound. Too poor fluidity will directly lead to defects such as bubbles and incomplete molding; too good fluidity often means a slower curing speed, a higher molding temperature, and a longer curing time, which is not suitable for large-scale production requirements. In addition, the fluidity difference will also cause inconsistent dimensions of the molded parts, resulting in out-of-tolerance, and appearance differences, resulting in color differences, thus affecting the final use of the product.
[0003] Some existing fluidity testing methods judge by measuring the length of the extruded part, but the length difference of the extruded part is not too large, and the fluidity index of the material cannot be accurately characterized; some other fluidity testing methods judge by measuring the length formed in a spiral cavity, but the length of the spiral cavity is not easy to measure, resulting in inaccurate tracking results. Summary of the Invention
[0004] In order to overcome the deficiencies in the prior art, the present invention provides a method and device for testing the fluidity of glass fiber reinforced phenolic molding compound, which has the advantages of simple testing method, easy and accurate testing judgment.
[0005] In order to achieve the above object, the present invention adopts the following technical solutions:
[0006] A method for testing the fluidity of glass fiber reinforced phenolic molding compound specifically includes the following steps:
[0007] Step S100: Place the test raw material under normal temperature and humidity conditions for at least 24 hours;
[0008] Step S200: Place the test mold on a hydraulic press and preheat it to the set temperature;
[0009] Step S300: Weigh a fixed amount of the test raw material and put it into the barrel of the test mold, and the hydraulic press applies a set pressure to the test raw material;
[0010] Step S400: Read the time T from the start of melting of the test raw material to extrusion through the gap between the test molds.
[0011] By adopting the above technical solution, the whole test operation is simple. At the same time, by judging the fluidity only by reading the time T from the start of melting of the test raw material to the extrusion from the gap between the test dies, the method for obtaining the result is simple in operation and highly operable, which is conducive to improving the test accuracy.
[0012] Optionally, the time T is the sum of t1 and t2. t1 is the time required for the applied pressure of the hydraulic press to change from the set pressure value until it drops to half, and t2 is the time required for the molten test raw material to be extruded from the gap between the test dies starting from the set pressure value when the applied pressure of the hydraulic press drops to half.
[0013] By adopting the above technical solution, more data can be obtained through the separate reading of the two time periods, which is conducive to fully studying the characteristics of the glass fiber reinforced phenolic molding compound.
[0014] Optionally, when the applied pressure of the hydraulic press drops to half of the set pressure value, the hydraulic press automatically replenishes the pressure to restore to the set pressure value.
[0015] By adopting the above technical solution, the molten test raw material can be extruded into the cavity under the same pressure, which is conducive to accurately judging the fluidity of the test raw material.
[0016] Optionally, after the same test raw material is tested three times, three time Ts are obtained, and the average value of the three time Ts is taken as the fluidity index of the test raw material.
[0017] By adopting the above technical solution, taking the average value of the three tests as the fluidity index of the test raw material makes the judgment of fluidity more accurate.
[0018] Optionally, the set pressure value is a fixed value within the range of 10 - 20 MPa.
[0019] By adopting the above technical solution, the set pressure value applied by the hydraulic press is within the range of 10 - 20 MPa, which is close to the actual pressure in the production process and is conducive to the fluidity test of the glass fiber reinforced phenolic molding compound.
[0020] Optionally, the set temperature is 150 - 180 °C.
[0021] By adopting the above technical solution, the set temperature is 150 - 180 °C, which is close to the actual temperature in the production process and is conducive to the fluidity test of the glass fiber reinforced phenolic molding compound.
[0022] Optionally, the test raw material is long fiber. Before the test, the test raw material is cut into a size of 30 - 100 mm.
[0023] By adopting the above technical solution, being close to the actual situation in the production process is conducive to the fluidity test of the glass fiber reinforced phenolic molding compound.
[0024] A testing device for the fluidity of glass fiber reinforced phenolic molding compound, comprising the above-mentioned testing mold and a hydraulic press. The testing mold includes a mold body, a barrel and a plunger; the mold body has a runner and a circular cavity communicating with the runner; the barrel is arranged on the upper surface of the mold body; the barrel is provided with upper and lower openings, and the lower opening thereof communicates with the upper opening of the runner; the plunger is inserted into the barrel from top to bottom; the hydraulic press is used to heat the mold body and the barrel and apply pressure to the plunger.
[0025] By adopting the above technical solution, the hydraulic press preheats the mold body and the barrel, then puts the test raw material into the barrel, then puts the plunger into the barrel, and then the hydraulic press applies force to the test raw material through the plunger. In this way, under the condition of pressurization and heating, the molten test raw material reaches the circular cavity in the mold body through the runner of the mold body, and after filling the cavity, it is extruded from the gap of the mold body. Since the cavity is circular, there is no damping like a spiral cavity during turning, which affects the normal flow, so as to better judge the fluidity.
[0026] Optionally, the hydraulic press has an upper heating plate and a lower heating plate; the lower heating plate abuts against the bottom surface of the mold body; the upper heating plate abuts against the top surface of the barrel.
[0027] By adopting the above technical solution, the simultaneous heating of the upper heating plate and the lower heating plate makes the preheating of the mold body faster, thereby shortening the test time and improving the test efficiency.
[0028] Optionally, the barrel has a cavity with upper and lower openings; the cavity is in the shape of a cylindrical groove and the lower opening is tapered; the diameter of the plunger is adapted to the diameter of the cavity so that the two move coaxially relative to each other; the bottom of the plunger is in the shape of a frustum of a cone with a wider top and a narrower bottom and its taper is greater than the taper of the lower opening of the cavity.
[0029] By adopting the above technical solution, the lower opening of the cavity is tapered, which is beneficial for the molten test raw material to enter the runner. The bottom of the plunger is in the shape of a frustum of a cone with a wider top and a narrower bottom and its taper is greater than the taper of the lower opening of the cavity, which is beneficial for reducing the residue of the test raw material in the cavity and at the same time reducing the possibility of the test raw material entering between the cylindrical surface of the plunger and the cylindrical side wall of the cavity. Description of the Drawings
[0030] Figure 1 is a schematic cross-sectional structure diagram of the testing device of the present invention.
[0031] Figure 2 is a schematic top view structure diagram of the upper template of the present invention.
[0032] Figure 3It is a top - view structural schematic diagram of the lower template of the present invention.
[0033] Figure 4 It is a top - view structural schematic diagram of the lower die backing plate of the present invention.
[0034] Explanation of reference numerals:
[0035] 10. Mold body; 100. Vertical runner; 101. Horizontal runner; 102. Cavity; 103. Test raw material;
[0036] 20. Upper template; 200. Upper runner hole; 201. Upper limit hole;
[0037] 30. Lower template; 301. Lower limit hole; 302. Upper threaded hole; 303. Runner bottom groove; 304. Horizontal runner groove; 305. Molding groove;
[0038] 40. Lower die backing plate; 400. Step hole;
[0039] 50. Limit post;
[0040] 60. Connecting bolt;
[0041] 70. Barrel; 700. Material cavity;
[0042] 80. Plunger. Detailed implementation manners
[0043] The following further elaborates on the present invention in conjunction with the attached Figures 1 - 4 drawings.
[0044] Embodiment 1: Disclose a test device for the fluidity of glass fiber - reinforced phenolic molding compound. Refer to Figure 1 , including a test mold (the hydraulic press is not shown); the test mold includes a mold body 10, a barrel 70, and a plunger 80; the mold body 10 includes an upper template 20, a lower template 30, and a lower die backing plate 40 distributed from top to bottom.
[0045] Refer to Figure 1 and Figure 2 , the upper template 20 is in the shape of a circular plate and is formed with three upper limit holes 201 evenly distributed in the circumferential direction; the upper template 20 is formed with an upper - wide - lower - narrow conical - hole - shaped upper runner hole 200; refer to Figure 1 and Figure 3 , the lower template 30 is formed with three lower limit holes 301 and upper threaded holes 302 evenly distributed in the circumferential direction; the lower limit holes 301 correspond to the upper limit holes 201 one by one; on the upper end surface of the lower template 30, a runner bottom groove 303, a horizontal runner groove 304, and a cylindrical - groove - shaped molding groove 305 are formed; the horizontal runner groove 304 is located in the radial direction between the runner bottom groove 303 and the molding groove 305; refer to Figure 1 and Figure 4, three stepped holes 400 evenly distributed in a circle are formed on the bottom surface of the lower die backing plate 40; the stepped holes 400 correspond to the upper threaded holes 302 one by one.
[0046] Reference Figure 1 , when the mold body 10 is assembled, three connecting bolts 60 sequentially pass through the stepped holes 400 of the lower die backing plate 40 and are screwed onto the upper threaded holes 302, so that the lower template 30 is fixed on the lower die backing plate 40, and the connecting bolts 60 are countersunk; then limit posts 50 are respectively inserted into the three lower limit holes 301 of the lower template 30, and then the upper template 20 is placed on the upper template 20 and the upper limit holes 201 of the upper template 20 are sleeved on the corresponding side limit posts 50. At this time, the upper runner hole 200 and the runner bottom groove 303 form a vertical runner 100, the lower surface of the upper template 20 and the horizontal runner groove 304 form a horizontal runner 101, the vertical runner 100 and the horizontal runner 101 form a runner, and the lower surface of the upper template 20 and the molding groove 305 form a cavity 102. In this embodiment, the cavity 102 is a circular sheet with a diameter of 100 mm and a height of 2 mm.
[0047] Reference Figure 1 , the barrel 70 is fixed on the upper end surface of the upper template 20, and the barrel 70 has a material cavity 700 with openings at both the upper and lower ends; the material cavity 700 is in the shape of a cylindrical groove and the lower end opening is tapered; the diameter of the material plug 80 is adapted to the diameter of the material cavity 700 so that the two move relative to each other coaxially; the bottom of the material plug 80 is in the shape of a frustum of a cone with a wider upper part and a narrower lower part and its taper is greater than the taper of the lower end opening of the material cavity 700. Among them, the outer diameter of the material cavity 700 is 120 mm, the inner diameter is 50 mm, and the height is 70 mm; the outer diameter of the material plug 80 is 50 mm and the height is 70 mm.
[0048] The hydraulic press has an upper heating plate and a lower heating plate; the hydraulic press can drive the upper heating plate to move up and down; during the test, the test mold is placed on the lower heating plate. At this time, the lower heating plate abuts against the lower die backing plate 40, and the hydraulic press drives the upper heating plate to descend and abut against the upper surface of the barrel 70, so that the upper heating plate and the lower heating plate preheat the test mold at the same time; the hydraulic press is mainly used to apply a set pressure to the material plug 80 and mainly supplement the pressure function. In order to facilitate the hydraulic press to apply pressure to the material plug 80, the upper heating plate is provided with a pressure application avoidance hole for the material plug 80 to pass through vertically.
[0049] Embodiment 2: Disclose a method for testing the fluidity of glass fiber reinforced phenolic molding compound, which specifically includes the following steps:
[0050] Step S100: Place the test raw material 103 under room temperature and humidity conditions for at least 24 hours; the test raw material 103 is glass fiber, and long fibers are selected for the glass fiber. Since the material form of long fibers is mainly sheet or coil, before testing, the test raw material 103 is cut into a size of 30 - 100 mm. Of course, short glass fibers, aramid fibers, carbon fibers, etc. can also be selected for the glass fiber.
[0051] Step S200: Place the test mold on the hydraulic press and preheat it to the set temperature; the set temperature is 150 - 180 °C; the specific operation is as follows. The whole test mold is placed on the lower heating plate of the hydraulic press. At this time, the lower heating plate contacts the lower die backing plate 40 of the test mold, and then the upper heating plate descends and abuts against the upper surface of the barrel 70. In this way, the upper heating plate and the lower heating plate preheat the test mold simultaneously.
[0052] Step S300: Weigh a fixed amount of the test raw material 103 and put it into the barrel 70 of the test mold, and the hydraulic press applies a set pressure to the test raw material 103; the fixed amount of the test raw material 103 is between 40 - 60 g; and the set pressure value is a fixed value within the range of 10 - 20 MPa. For the convenience of subsequent description, the set pressure value is selected as 10 MPa. During specific operation, the test raw material 103 is put into the material cavity 700 of the barrel 70, and then a plunger 80 is put into the material cavity 700. The hydraulic press applies pressure to the plunger 80 to apply pressure to the test raw material 103. In this way, the test raw material 103 starts to melt under the conditions of pressurization and heating.
[0053] Step S400: Read the time T from the start of melting of the test raw material 103 to extrusion through the gap between the test molds. The specific operation is as follows: Read the time t1 required for the applied pressure of the hydraulic press to change from the set pressure value until it drops to half, that is, the time t1 required for the applied pressure value of the hydraulic press to drop from 10 MPa to 5 MPa. The starting point of timing of the time t1 is when the test raw material 103 starts to melt. When the applied pressure of the hydraulic press drops to half of the set pressure value, it indicates that the test raw material 103 is completely melted. Then the hydraulic press replenishes the pressure to make the applied pressure value become 10 MPa. Next, the hydraulic press extrudes with a pressure of 10 MPa so that the molten test raw material 103 enters the cavity 102 through the runner of the test mold and finally extrudes through the gap between the upper template 20 and the lower template 30. At this time, read it as t2. There is no interval between t1 and t2, and the sum of t1 and t2 is the time T.
[0054] Test three times according to the above method to obtain three times T, and take the average value of the three times T as the fluidity index of the test raw material.
[0055] A standard sample is required for each test. The determination principle of the standard sample is the material that passed the previous test and is within the shelf life. The process parameter conditions of the test sample and the standard sample need to be the same, and the read T is compared year-on-year.
[0056] The above are all preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention shall be covered within the protection scope of the present invention.
Claims
1. A method for testing the fluidity of glass fiber reinforced phenolic molding compound, characterized in that: The specific steps include: Step S100: placing the test raw material under normal temperature and humidity conditions for at least 24 hours; Step S200: placing the test mold on a hydraulic press and preheating it to a set temperature; Step S300: weighing a fixed amount of test raw materials and putting them into the barrel of the test mold, and applying a set pressure to the test raw materials by the hydraulic press; Step S400: reading the time T from the start of melting of the test raw material to its extrusion from the gap between the test dies.
2. A method for testing the fluidity of a glass fiber reinforced phenolic molding compound according to claim 1, characterized in that: Time T is the sum of t1 and t2, t1 is the time required for the applied pressure of the hydraulic press to change from the set pressure value to half, and t2 is the time required for the applied pressure of the hydraulic press to drop to half of the set pressure value until the molten test material is squeezed out from the gap between the test molds.
3. A method for testing the fluidity of glass fiber reinforced phenolic molding compound according to claim 2, characterized in that: When the applied pressure of the hydraulic press drops to half of the set pressure value, the hydraulic press automatically replenishes the pressure to restore to the set pressure value.
4. A method for testing the fluidity of glass fiber reinforced phenolic molding compound according to claim 1, characterized in that: After three tests on the same test material, three times T are obtained, and the average value of the three times T is taken as the fluidity index of the test material.
5. A method for testing the fluidity of glass fiber reinforced phenolic molding compound according to claim 1, characterized in that: The set pressure value is a fixed value within the range of 10-20MPa.
6. A method for testing the fluidity of glass fiber reinforced phenolic molding compound according to claim 1, characterized in that: Set the temperature to 150-180℃.
7. A method for testing the fluidity of glass fiber reinforced phenolic molding compound according to claim 1, characterized in that: The test material is long fiber. Before testing, the test material is cut into a size of 30-100mm.
8. A testing device for the fluidity of glass fiber reinforced phenolic molding compound, characterized in that: The test mold and hydraulic press comprise any one of claims 1 to 7, wherein the test mold comprises a mold body (10), a barrel (70) and a plug (80); the mold body (10) has a flow channel and a circular cavity (102) connected to the flow channel; the barrel (70) is arranged on the upper surface of the mold body (10); the barrel (70) is arranged with upper and lower openings and its lower end opening is connected to the upper end opening of the flow channel; the plug (80) is inserted into the barrel (70) from top to bottom; the hydraulic press is used to heat the mold body (10) and the barrel (70) and to apply pressure to the plug (80).
9. A testing device for fluidity of glass fiber reinforced phenolic molding compound according to claim 8, characterized in that: The hydraulic press comprises an upper heating plate and a lower heating plate; the lower heating plate abuts against the bottom surface of the mold body (10); and the upper heating plate abuts against the top surface of the barrel (70).
10. A testing device for fluidity of glass fiber reinforced phenolic molding compound according to claim 8, characterized in that: The barrel (70) has a material cavity (700) with upper and lower openings; the material cavity (700) is in the shape of a cylindrical groove and the lower end opening is narrowed into a cone; the diameter of the material plug (80) is adapted to the diameter of the material cavity (700) so that the two can move coaxially relative to each other; the bottom of the material plug (80) is in the shape of a truncated cone that is wide at the top and narrow at the bottom and its taper is greater than the taper of the lower end opening of the material cavity (700).