Low dielectric constant glass fiber cloth and method for manufacturing the same
By synergistically designing a core-layer nano-closed-pore structure and a dense shell, combined with gradient air cooling and pulpless weaving processes, the problems of high energy consumption, high cost, and signal loss of existing low dielectric constant glass fiber cloths have been solved, achieving signal integrity and resistance to damp heat in high-frequency communication, and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI JINRUI ELECTRONICS GLASS FIBER
- Filing Date
- 2026-04-30
- Publication Date
- 2026-07-24
AI Technical Summary
Existing low dielectric constant glass fiber cloths suffer from high energy consumption, high cost, decreased fiber mechanical properties, severe signal transmission loss and delay, and poor resistance to damp heat during the preparation process, and cannot meet the signal integrity requirements of high-frequency communication and PCBs.
By employing a synergistic design of a core-layer nanoporous structure and a dense shell, and through chemical modification and physical pore closing, combined with a three-stage gradient air-cooling process and an online low-dielectric pre-impregnation agent, slurry-free weaving is achieved, constructing a dielectric constant gradient transition layer to form a high-strength, low-dielectric-performance glass fiber cloth.
It achieves a balance between ultra-low dielectric properties and high strength, improves the product's resistance to damp heat and signal integrity, reduces production energy consumption and overall costs, and is suitable for ultra-high frequency communication scenarios.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of glass fiber cloth preparation technology, and in particular to a low dielectric constant glass fiber cloth and its manufacturing method. Background Technology
[0002] With the evolution of 5G communication to 6G, the rapid development of AI computing power, and the rapid implementation of autonomous driving technology, the requirements for the integrity of high-frequency and high-speed signal transmission in electronic systems continue to increase. Low dielectric constant glass fiber cloth (referred to as low dielectric electronic cloth) is the core reinforcing skeleton material for high-frequency copper clad laminates and printed circuit boards (PCBs). Its dielectric properties, mechanical properties, resistance to damp heat, and dimensional stability directly determine the signal transmission quality and reliability of PCBs.
[0003] The core of current mainstream low-dielectric electronic fabric manufacturing technology is to achieve low-dielectric properties through chemical modification of the glass formulation. This involves reducing the content of alkali metal oxides and increasing the proportion of SiO2 and B2O3 to reduce the polarization sites of the material in alternating electromagnetic fields, as exemplified by NE and D glass systems. However, this technical route has inherent bottlenecks that cannot be overcome: On the one hand, in pursuit of even lower dielectric constants, the SiO2 content needs to be continuously increased, leading to a significant increase in glass melting temperature, a sharp increase in melt viscosity, and a significant narrowing of the drawing window. This not only significantly increases energy consumption and manufacturing costs but also causes an increase in fiber breakage rate and a significant decrease in fiber mechanical properties. On the other hand, there is a significant abrupt change in dielectric constant between solid glass fiber and low-dielectric resin. In the millimeter-wave frequency band above 28 GHz, interface polarization is easily generated, leading to a sharp increase in signal transmission loss, delay, and crosstalk, making it unsuitable for next-generation ultra-high frequency communication scenarios.
[0004] To address these issues, the industry has attempted to physically reduce dielectric strength by introducing air (dielectric constant = 1) into porous glass fibers. However, existing porous glass fibers are mostly open-cell structures, which readily absorb moisture from the environment, causing a sharp deterioration in dielectric properties under humid and hot conditions, failing to meet the humid and hot resistance requirements of PCB manufacturing processes. At the same time, existing electronic cloth manufacturing processes must go through a "sizing, weaving, and high-temperature desizing" process. Residual sizing material directly deteriorates dielectric properties, and high-temperature desizing above 400°C can easily cause irreversible loss of fiber strength, further limiting product performance and production yield.
[0005] Therefore, the present invention provides a method for manufacturing low dielectric constant glass fiber cloth to meet market demand. Summary of the Invention
[0006] To achieve the above objectives, the present invention provides the following technical solution: a low dielectric constant glass fiber cloth, wherein the mass proportions of each component are as follows: 68-74 parts of silicon dioxide, 18-23 parts of boron trioxide, 3-5 parts of aluminum trioxide, 0.8-1.5 parts of magnesium oxide, 0.3-0.7 parts of calcium oxide, 0.5-0.8 parts of zinc oxide, 0.25-0.8 parts of composite silane coupling agent, 0.05-0.3 parts of low dielectric epoxy resin, 0.05-0.25 parts of low dielectric polyphenylene ether resin, 0.03-0.15 parts of polytetrafluoroethylene micro powder, and 0.02-0.1 parts of curing and functional additives.
[0007] Preferably, the silica raw material quartz sand has a purity ≥99.95% and a total content of mobile impurities such as iron, sodium, and potassium ≤50ppm; the boric acid raw material boron trioxide has a purity ≥99.9% and an alkali metal impurity content ≤20ppm; the alumina raw material alumina has a purity ≥99.99% and an average particle size ≤5μm; the magnesium oxide is selected from magnesium carbonate or basic magnesium carbonate with a purity ≥99.9% and an alkali metal impurity content ≤30ppm; the calcium oxide is selected from calcium carbonate with a purity ≥99.9% and an average particle size ≤10μm; and the zinc oxide is selected from zinc carbonate with a purity ≥99.99% and an average particle size ≤10μm. Zinc oxide with a diameter ≤3μm; the composite silane coupling agent is a mixture of epoxy silane coupling agent, fluorinated silane coupling agent, and perfluoroalkyl silane coupling agent in a mass ratio of (2~3):(1~2):1; the low-dielectric epoxy resin is bisphenol F type low-dielectric epoxy resin with an epoxy equivalent of 170~200g / eq; the low-dielectric polyphenylene ether resin is epoxy-terminated modified polyphenylene ether resin; the polytetrafluoroethylene micro powder is spherical ultra-low-dielectric micro powder with an average particle size of 200~500nm; the curing and functional additives are a mixture of low-temperature epoxy curing agent, resin compatibilizer, and micro powder dispersant in a mass ratio of 2:1:1.
[0008] A method for producing the above-mentioned low dielectric constant glass fiber cloth includes the following steps:
[0009] Step 1: Prepare core glass batch and shell glass batch. The core glass batch contains low-dimerborosilicate glass matrix and SiO2-coated controllable decomposition pore-forming agent. The shell glass batch is a high-density low-dimerborosilicate glass matrix without pore-forming agent. The two batches are homogenized, dried and pre-sintered to obtain core clinker and shell clinker.
[0010] Step 2: Coaxial melting and fiber formation. The core and shell molten materials are added to the inner and outer crucibles of the double-crucible coaxial melting furnace, respectively. They are then fully electric melted under a protective atmosphere to obtain uniform, bubble-free core and shell glass melts. The two sets of glass melts flow out simultaneously through a coaxial platinum-rhodium baffle plate and are drawn into fibers at high speed. At the same time, a three-stage gradient air cooling process is used to first solidify the shell layer and then trigger the decomposition of the pore-forming agent in situ to form uniform nano-closed pores. Finally, the core-shell closed-pore structure glass fiber is obtained. During the fiber drawing process, a low-dielectric pre-wetting agent is applied online and wound into a raw fiber cake.
[0011] Step 3: Electronic yarn preparation. The original yarn cake is dried under vacuum at low temperature and twisted with low tension and ultra-low twist to obtain core-shell closed-cell low dielectric electronic yarn.
[0012] Step 4: Sizing-free weaving. The low dielectric electron yarn is shaped by low-tension sizing-free warping, low-damage air-jet weaving, and dry plasma purification to obtain the greige fabric.
[0013] Step 5: Modification and Shaping. A multilayer modification solution matching the dielectric constant gradient of the fiber shell and downstream matrix resin is prepared. The fabric is continuously impregnated and modified in stages, then cured and shaped by gradient heating, followed by cooling and antistatic treatment to obtain the finished low dielectric constant glass fiber cloth.
[0014] Preferably, the core glass compound, by weight, comprises 95-98 parts of low-dimer borosilicate glass matrix and 2-5 parts of SiO2-coated controllable decomposition pore-forming agent; the low-dimer borosilicate glass matrix comprises 65-72 parts of high-purity quartz sand, 18-25 parts of high-purity boric acid, 3-5 parts of high-purity alumina, and 1-2 parts of alkaline earth metal oxide; the shell glass compound, by weight, comprises 70-76 parts of high-purity quartz sand, 14-20 parts of high-purity boric acid, 3-5 parts of high-purity alumina, and 0.5-1 parts of high-purity zinc oxide.
[0015] Preferably, the core of the SiO2-coated controllable decomposition pore-forming agent is nano-basic magnesium carbonate or nano-calcium bicarbonate, the SiO2 coating thickness is 30-80 nm, and the decomposition temperature is 1150-1250 °C; the pre-sintering treatment temperature is 1100-1120 °C, and the time is 1.5-2.5 h.
[0016] Preferably, the melting temperature of the coaxial double crucible melting is 1550-1580℃, the protective atmosphere is high-purity nitrogen, and the melting time is 4-6h; the ratio of the inner hole area to the outer ring area of the coaxial platinum-rhodium filament is (4-5):1, the filament temperature is 1260-1280℃, the wire drawing speed is 3000-4000m / min, and the diameter of the glass fiber monofilament obtained is 4.5-6μm.
[0017] Preferably, the three-stage gradient air cooling process includes:
[0018] First stage: 0-50cm below the stencil, temperature 1220-1280℃, slow cooling to completely solidify the shell glass;
[0019] Second stage: 50-150cm below the stencil, at a temperature of 1120-1220℃, the pore-forming agent is decomposed, and nano-closed pores are formed in situ in the core glass, with a closed pore rate of 20-35% and a pore size of 50-200nm.
[0020] The third stage: 150cm below the stencil, rapidly air-cooled to room temperature to complete fiber curing.
[0021] Preferably, the low-dielectric pre-impregnation agent comprises, by weight, 60-70% low-hydroxyl fluorine-modified siloxane film-forming agent, 10-20% silane coupling agent, and 10-30% anhydrous ethanol solvent, and the coating amount is 0.3-0.5% of the fiber mass.
[0022] Preferably, the single yarn tension of the low-tension, sizing-free warping is 4-6 cN, and the warping environment is constant temperature and humidity; the warp opening of the low-damage air-jet weaving is 20-25 mm, and the weft flight tension is 3-5 cN; the dry plasma purification is room temperature plasma cleaning with a power of 100-200 W and a processing time of 30-60 s.
[0023] Preferably, the multilayer modified liquid is a 2-4 layer gradient modified liquid, and the dielectric constant of each modified liquid decreases sequentially from the fiber shell to the downstream matrix resin, with the difference in dielectric constant between two adjacent modified liquid layers ≤0.5; the gradient heating curing temperature is 100-170℃, with segmented heat preservation curing, and the fabric surface tension ≤10N / m throughout the process.
[0024] The beneficial effects of this invention are:
[0025] 1. This invention employs a synergistic dielectric reduction mechanism of chemical modification and physical pore closing. Air (dielectric constant = 1) is introduced through the core layer nanopores, achieving ultra-low dielectric properties without the need for an extremely high silicon and high boron formulation. At the same time, the dense shell layer ensures the mechanical strength of the fiber, thus achieving a balance between ultra-low dielectric and high strength.
[0026] 2. This invention uses a three-stage gradient air cooling process to first solidify the shell layer to form a dense barrier, and then trigger the decomposition of the pore-forming agent to form a closed-pore structure in situ in the core layer, completely isolating the pores from the external environment. This solves the industry pain points of existing porous glass fiber open-pore structures being prone to moisture absorption and dielectric properties deteriorating under humid heat, and greatly improves the product's resistance to humid heat and environmental stability.
[0027] 3. This invention, through the design of an online low-dielectric pre-impregnation agent, endows the fiber with sufficient cohesion and abrasion resistance, realizing sizing-free weaving. It eliminates the sizing and high-temperature desizing processes of the existing technology, thereby eliminating the negative impact of sizing residue on dielectric properties and avoiding the strength damage of the fiber caused by high-temperature desizing. At the same time, it shortens the process flow and reduces melting energy consumption and overall manufacturing costs.
[0028] 4. This invention constructs a continuous dielectric constant gradient transition layer from the fiber shell to the downstream matrix resin, eliminating interface polarization, signal reflection and crosstalk caused by abrupt changes in dielectric constant, and significantly improving signal integrity in ultra-high frequency scenarios. Detailed Implementation
[0029] To enable those skilled in the art to better understand the technical solutions of this application, some non-limiting embodiments are further disclosed below to provide a more detailed description of this application.
[0030] All reagents used in this application are commercially available or can be prepared by the methods described in this application.
[0031] The raw materials used in the embodiments of this invention are all electronic-grade high-purity (total impurity content ≤50ppm), the equipment used are all conventional industrial equipment in the field, and the testing methods all adopt industry-standard methods, as follows:
[0032] Dielectric constant (Dk) and dielectric loss factor (Df): The performance at frequencies of 10 GHz and 28 GHz was tested using the resonant cavity method.
[0033] Monofilament breaking strength: tested according to GB / T 7690.3-2001 "Determination of breaking strength and elongation at break of glass fiber yarn";
[0034] Moisture and heat resistance: The sample was placed in an 85℃ / 85% RH constant temperature and humidity chamber for 1000h, and the change rate of Dk before and after the placement was tested;
[0035] Heat shrinkage rate: According to GB / T 20102-2006 "Test Methods for Glass Fiber Cloth", the warp heat shrinkage rate at 180℃ for 10 min was tested;
[0036] Fiber breakage rate: The number of fiber breaks per kilometer during the fiber drawing process.
[0037] Some of the material sources are shown in Table 1:
[0038] Source of materials:
[0039] Table 1
[0040] Preparation example:
[0041] Example 1
[0042] Step 1: Preparation of core glass batch and shell glass batch:
[0043] By weight, the core layer composition is as follows: 68 parts high-purity quartz sand, 22 parts high-purity boric acid, 4 parts high-purity alumina, 0.8 parts high-purity magnesium carbonate, 0.7 parts high-purity calcium carbonate, and 4.5 parts SiO2-coated controllable decomposition pore-forming agent (the core of the pore-forming agent is nano-basic magnesium carbonate, the SiO2 coating thickness is 50nm, and the decomposition temperature is 1180±20℃).
[0044] Shell layer mix: 72 parts high-purity quartz sand, 18 parts high-purity boric acid, 4.5 parts high-purity alumina, and 0.5 parts high-purity zinc oxide; the two mixes were placed in a planetary ball mill, anhydrous ethanol was added as the grinding medium, and the mixture was ball-milled for 3 hours to obtain a uniform powder with an average particle size of 8 μm; the powder was then placed in a vacuum drying oven at 120℃ for 8 hours to completely remove moisture and ethanol; the powder was then placed in a corundum crucible and pre-sintered in air at 1100℃ for 2 hours to obtain core and shell layer clinker.
[0045] Step 2, Coaxial Melting and Fiber Formation:
[0046] The core and shell molten materials were added to the inner crucible (core layer) and outer crucible (shell layer) of a double-crucible coaxial melting furnace, respectively. The crucibles were made of platinum-rhodium alloy. Full electric melting heating was used, with a melting temperature of 1560℃. High-purity nitrogen gas was introduced throughout the process to prevent B2O3 volatilization and premature decomposition of the pore-forming agent. The melting time was 5 hours, and low-frequency electromagnetic stirring was used to obtain bubble-free and streak-free core and shell glass melts. The two sets of glass melts flowed out synchronously through a coaxial platinum-rhodium alloy stencil. The ratio of the inner hole area to the outer ring area of the stencil was 4:1, and the stencil temperature was 1270℃. A high-speed wire drawing machine was used to draw the glass into continuous fibers with a single filament diameter of 6μm at a traction speed of 3200m / min.
[0047] The fiber drawing process employs a three-stage gradient air-cooling system: Stage 1 (0-50cm below the stencil): Temperature 1230-1270℃, slow cooling to solidify the outer glass and form a dense outer shell; Stage 2 (50-150cm): Temperature 1130-1230℃, the pore-forming agent coating layer breaks down, releasing CO2. The core glass is in a highly viscoelastic state, preventing gas escape and forming a closed-pore structure with a pore size of 50-200nm in situ, with a porosity of 20±2%; Stage 3 (below 150cm): rapid air cooling to room temperature to complete fiber solidification.
[0048] After the fiber is cured, it is coated online with a low-dielectric pre-wetting agent with the following formula: 60% low-hydroxyl fluorine-modified siloxane film-forming agent, 20% epoxy silane coupling agent, and 20% anhydrous ethanol. The coating amount is 0.4% of the fiber mass. After being dried rapidly by infrared at 100℃, it is wound into a raw yarn cake.
[0049] Step 3, Electronic yarn preparation:
[0050] The raw yarn cake was dried in a vacuum drying oven at 110℃ and -0.09MPa for 8 hours; it was then unwound using a low-tension unwinding device, and the two strands were combined. The yarn was twisted with an ultra-low twist of 50 twists / meter, and the tension of each yarn was controlled in a closed loop with a tension deviation of ≤±3%. The yarn was then inspected along its entire length using an online laser detector, and unqualified yarns with fuzz or shell damage were removed to obtain a core-shell closed-cell low-dielectric electron yarn.
[0051] Step 4, Weaving without sizing:
[0052] The electronic yarn is warped under low tension without sizing in a warping workshop with constant temperature and humidity (22±1℃, humidity 55±3%) and a cleanliness level of Class 1000. The single yarn tension is 6cN, and the warp beam is obtained directly after warping without the need for sizing. It is woven on a high-speed air-jet loom with a weft buffer device, with a warp yarn opening of 25mm and a weft yarn flight tension of 4cN. The plain weave is used to weave 1080 model greige fabric. The entire process is visually inspected online, and defects are removed in real time. The woven greige fabric is then cleaned with room temperature plasma at a power of 150W for 45 seconds to remove trace impurities on the surface, resulting in a purified greige fabric.
[0053] Step 5: Modification and Finalization
[0054] Three-layer gradient modified solutions were prepared, all using anhydrous ethanol as the solvent:
[0055] Bottom transition fluid: 5% epoxy silane coupling agent, 2% low dielectric epoxy resin (Dk=3.8), 93% anhydrous ethanol, overall Dk≈3.9, matching shell glass Dk(4.2).
[0056] Intermediate transition fluid: 4% fluorinated modified silane coupling agent, 2% low-molecular-weight polyphenylene ether resin (Dk=3.4), 94% anhydrous ethanol, with an overall Dk≈3.5;
[0057] Surface coating solution: 3% perfluoroalkyl silane coupling agent, 1% PTFE micro powder (Dk=2.1), 96% anhydrous ethanol, with an overall Dk≈3.1, matching the downstream low dielectric resin Dk; a vertical three-step impregnation unit is used, in which the fabric is passed through the bottom layer, middle layer, and surface layer modification solution in sequence, with each impregnation time being 12s, and the liquid amount is controlled by precision extrusion rollers to be 1.2% of the fabric weight; the impregnated fabric enters a segmented hot air setting oven, with low tension control throughout (fabric surface tension 10N / m), and gradient temperature rise curing: 100℃ for 2min to remove solvent, 130℃ for 3min to cure the bottom transition layer, and 160℃ for 4min to cure the middle and surface transition layers, while simultaneously completing heat setting; the cured fabric base is cooled to room temperature and subjected to weak plasma antistatic treatment online to obtain the finished low dielectric constant glass fiber cloth.
[0058] Example 2
[0059] The only difference from Example 1 is:
[0060] In step 1, the core layer mix consists of 70 parts high-purity quartz sand, 20 parts high-purity boric acid, 3.5 parts high-purity alumina, 0.6 parts high-purity magnesium carbonate, 0.4 parts high-purity calcium carbonate, and 5.5 parts SiO2-coated controllable decomposition pore-forming agent; the shell layer mix consists of 74 parts high-purity quartz sand, 16 parts high-purity boric acid, 4 parts high-purity alumina, and 0.6 parts high-purity zinc oxide; the pre-sintering temperature is 1110℃.
[0061] In step 2, the melting temperature is 1570℃, the ratio of the inner hole area to the outer ring area of the spinneret is 4.5:0.5, the spinneret temperature is 1275℃, the drawing speed is 3500m / min, and the single filament diameter is 5μm; the temperature of the second stage of gradient air cooling is 1120-1240℃, and the closed-cell rate is 28±2%; the pre-sizing agent formula is: 65% low-hydroxyl fluorine-modified siloxane film-forming agent, 15% epoxy silane coupling agent, and 20% anhydrous ethanol.
[0062] In step 3, the strands are combined into 4 strands with a twist of 40 twists / meter;
[0063] In step 4, a 2116 type greige fabric is woven with a warping tension of 5cN and a warp yarn opening of 22mm.
[0064] In step 5, the three-layer gradient modified liquid was adjusted as follows: bottom layer Dk≈3.7, middle layer Dk≈3.3, and top layer Dk≈2.9; the maximum curing and shaping temperature was 165℃; the remaining steps and process parameters were completely consistent with those in Example 1.
[0065] Example 3
[0066] The only difference from Example 1 is:
[0067] In S1, the core layer composition consists of 72 parts high-purity quartz sand, 18 parts high-purity boric acid, 3 parts high-purity alumina, 0.4 parts high-purity magnesium carbonate, 0.2 parts high-purity calcium carbonate, and 6.4 parts SiO2-coated controllable decomposition pore-forming agent; the shell layer composition consists of 76 parts high-purity quartz sand, 14 parts high-purity boric acid, 3.5 parts high-purity alumina, and 0.5 parts high-purity zinc oxide; the pre-sintering temperature is 1120℃.
[0068] In S2, the melting temperature is 1580℃, the ratio of the inner hole area to the outer ring area of the spinneret is 5:1, the spinneret temperature is 1280℃, the drawing speed is 3800m / min, and the single filament diameter is 4.5μm; the temperature of the second stage of gradient air cooling is 1110-1250℃, and the closed-cell rate is 35±2%; the pre-sizing agent formula is: 70% low-hydroxyl perfluorinated modified siloxane film-forming agent, 10% fluorinated modified silane coupling agent, and 20% anhydrous ethanol;
[0069] In S3, the ply is 4-ply, and the twist is 30 twists / meter;
[0070] In S4, a 106-type ultra-thin greige fabric is woven with a warping tension of 4cN and a warp opening of 20mm.
[0071] In S5, the three-layer gradient modified liquid was adjusted as follows: bottom layer Dk≈3.5, middle layer Dk≈3.0, and surface layer Dk≈2.6; the maximum curing and shaping temperature was 170℃; the remaining steps and process parameters were completely consistent with those in Example 1.
[0072] Comparative Example 1
[0073] This comparative example uses conventional methods to prepare mainstream NE-type low-dielectric electronic cloth as a performance control. The specific steps are as follows:
[0074] Step 1, Preparation of glass batch: According to the NE glass standard formula, weigh 58 parts of high-purity quartz sand, 25 parts of high-purity boric acid, 8 parts of high-purity alumina, and 9 parts of alkaline earth metal oxides, and obtain clinker by ball milling, drying, and pre-sintering.
[0075] Step 2, Melting and Drawing: The molten material is added to a single-crucible platinum-rhodium alloy melting furnace and melted electrically at 1620℃ to obtain a uniform glass melt; it is then drawn into a solid glass fiber with a single filament diameter of 6μm through a single-hole platinum-rhodium bristle at a drawing temperature of 1300℃ and a traction speed of 3200m / min. The fiber is then coated with a conventional textile sizing agent online and wound into a raw filament cake.
[0076] Step 3, Electronic yarn preparation: The raw yarn cake is dried at 130℃, unwound, twisted, and twisted at a conventional twist of 150 twists / meter to obtain NE type electronic yarn;
[0077] Step 4, Weaving: The electronic yarn is warped, sized, and woven on a high-speed air-jet loom to form a 1080 type grey fabric;
[0078] Step 5, Post-processing: The fabric is desized at 420℃, split open by high-pressure hydroentangling, impregnated with conventional aminosilane coupling agent, and dried and shaped at 150℃ to obtain the finished NE-type low-dielectric electronic fabric.
[0079] The results of the physical property tests are shown in Table 2:
[0080] Table 2
[0081] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A low dielectric constant glass fiber cloth, characterized in that, The mass percentages of each component are as follows: 68-74 parts silica, 18-23 parts boron trioxide, 3-5 parts aluminum trioxide, 0.8-1.5 parts magnesium oxide, 0.3-0.7 parts calcium oxide, 0.5-0.8 parts zinc oxide, 0.25-0.8 parts composite silane coupling agent, 0.05-0.3 parts low-dielectric epoxy resin, 0.05-0.25 parts low-dielectric polyphenylene ether resin, 0.03-0.15 parts polytetrafluoroethylene micro powder, and 0.02-0.1 parts curing and functional additives.
2. The low dielectric constant glass fiber cloth as described in claim 1, characterized in that: The silica raw material, quartz sand, has a purity ≥99.95%, and the total content of mobile impurities such as iron, sodium, and potassium is ≤50ppm; the boric acid raw material, boron trioxide, has a purity ≥99.9%, and the content of alkali metal impurities is ≤20ppm; the alumina raw material, aluminum trioxide, has a purity ≥99.99%, and an average particle size ≤5μm; the magnesium oxide is selected from magnesium carbonate or basic magnesium carbonate with a purity ≥99.9% and an alkali metal impurity content ≤30ppm; the calcium oxide is selected from calcium carbonate with a purity ≥99.9% and an average particle size ≤10μm. Zinc oxide with a purity of ≥99.99% and an average particle size of ≤3μm was selected. The composite silane coupling agent is a mixture of epoxy-based silane coupling agent, fluorinated silane coupling agent, and perfluoroalkyl silane coupling agent in a mass ratio of (2~3):(1~2):1; the low-dielectric epoxy resin is a bisphenol F type low-dielectric epoxy resin with an epoxy equivalent of 170~200 g / eq; the low-dielectric polyphenylene ether resin is an epoxy-terminated modified polyphenylene ether resin; the polytetrafluoroethylene micro powder is a spherical ultra-low-dielectric micro powder with an average particle size of 200~500 nm; the curing and functional additives are a mixture of low-temperature epoxy curing agent, resin compatibilizer, and micro powder dispersant in a mass ratio of 2:1:
1.
3. A method for producing a low dielectric constant glass fiber cloth as described in any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Prepare core glass batch and shell glass batch. The core glass batch contains low-dimerborosilicate glass matrix and SiO2-coated controllable decomposition pore-forming agent. The shell glass batch is a high-density low-dimerborosilicate glass matrix without pore-forming agent. The two batches are homogenized, dried and pre-sintered to obtain core clinker and shell clinker. Step 2: Coaxial melting and fiber formation. The core and shell molten materials are added to the inner and outer crucibles of the double-crucible coaxial melting furnace, respectively. They are then fully electric melted under a protective atmosphere to obtain uniform, bubble-free core and shell glass melts. The two sets of glass melts flow out simultaneously through a coaxial platinum-rhodium baffle plate and are drawn into fibers at high speed. At the same time, a three-stage gradient air cooling process is used to first solidify the shell layer and then trigger the decomposition of the pore-forming agent in situ to form uniform nano-closed pores. Finally, the core-shell closed-pore structure glass fiber is obtained. During the fiber drawing process, a low-dielectric pre-wetting agent is applied online and wound into a raw fiber cake. Step 3: Electronic yarn preparation. The original yarn cake is dried under vacuum at low temperature and twisted with low tension and ultra-low twist to obtain core-shell closed-cell low dielectric electronic yarn. Step 4: Sizing-free weaving. The low dielectric electron yarn is shaped by low-tension sizing-free warping, low-damage air-jet weaving, and dry plasma purification to obtain the greige fabric. Step 5: Modification and shaping. Prepare a multilayer modification liquid that matches the dielectric constant gradient of the fiber shell and the downstream matrix resin. Modify the fabric by continuous step-by-step impregnation, then cure and shape it by gradient heating, and cool it for antistatic treatment to obtain the finished glass fiber cloth with low dielectric constant.
4. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 1, characterized in that: The core glass compound, by weight, comprises 95-98 parts of low-dimerborosilicate glass matrix and 2-5 parts of SiO2-coated controllable decomposition pore-forming agent; the low-dimerborosilicate glass matrix comprises 65-72 parts of high-purity quartz sand, 18-25 parts of high-purity boric acid, 3-5 parts of high-purity alumina, and 1-2 parts of alkaline earth metal oxide; the shell glass compound, by weight, comprises 70-76 parts of high-purity quartz sand, 14-20 parts of high-purity boric acid, 3-5 parts of high-purity alumina, and 0.5-1 parts of high-purity zinc oxide.
5. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 3, characterized in that: The core of the SiO2-coated controllable decomposition pore-forming agent is nano-basic magnesium carbonate or nano-calcium bicarbonate, the SiO2 coating thickness is 30-80 nm, and the decomposition temperature is 1150-1250℃; the pre-sintering treatment temperature is 1100-1120℃, and the time is 1.5-2.5 h.
6. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 3, characterized in that: The melting temperature of the coaxial double crucible melting is 1550-1580℃, the protective atmosphere is high-purity nitrogen, and the melting time is 4-6h; the ratio of the inner hole area to the outer ring area of the coaxial platinum-rhodium filament is (4-5):1, the filament temperature is 1260-1280℃, the wire drawing speed is 3000-4000m / min, and the diameter of the glass fiber monofilament obtained is 4.5-6μm.
7. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 6, characterized in that: The three-stage gradient air cooling process includes: First stage: 0-50cm below the stencil, temperature 1220-1280℃, slow cooling to completely solidify the shell glass; Second stage: 50-150cm below the stencil, at a temperature of 1120-1220℃, the pore-forming agent is decomposed, and nano-closed pores are formed in situ in the core glass, with a closed pore rate of 20-35% and a pore size of 50-200nm. The third stage: 150cm below the stencil, rapidly air-cooled to room temperature to complete fiber curing.
8. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 3, characterized in that: The low-dielectric pre-impregnating agent comprises, by weight, 60-70% low-hydroxyl fluorine-modified siloxane film-forming agent, 10-20% silane coupling agent, and 10-30% anhydrous ethanol solvent, and the coating amount is 0.3-0.5% of the fiber mass.
9. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 3, characterized in that: The single yarn tension of the low-tension, sizing-free warping is 4-6 cN, and the warping environment is constant temperature and humidity; the warp opening of the low-damage air-jet weaving is 20-25 mm, and the weft flight tension is 3-5 cN; the dry plasma purification is room temperature plasma cleaning with a power of 100-200 W and a processing time of 30-60 s.
10. The method for manufacturing low dielectric constant glass fiber cloth as described in claim 3, characterized in that: The multilayer modified liquid consists of 2-4 layers of gradient modified liquid. The dielectric constant of each modified liquid decreases sequentially from the fiber shell to the downstream matrix resin, and the difference in dielectric constant between two adjacent modified liquid layers is ≤0.
5. The gradient heating curing temperature is 100-170℃, with segmented heat preservation curing, and the fabric surface tension is ≤10N / m throughout the process.