CN108249770A - One kind contains Y2O3Floride-free dielectric glass fibre and preparation method thereof - Google Patents

Abstract

The invention provides a fluorine-free glass fiber with low dielectric constant and low loss, and its dielectric constant and dielectric loss can reach a better level. The dielectric constant and dielectric loss at room temperature 1MHz are 4.12~4.67 and 5.41×10 ^‑3 ~7.84×10 ^‑3 , respectively. The glass fiber has its dielectric properties optimized by adding rare earth elements (Y ₂ O ₃ ). The glass fiber composition is made of mole percent raw materials: SiO ₂ 56%~64%, B ₂ O ₃ 16%~20%, Al ₂ O ₃ 8%~14%, Na ₂ O 0.5%~1%, CaO 8%~12%, Y ₂ O ₃ 0.5%~8%. The glass fiber involved in the invention not only has excellent low dielectric properties, but also has good thermal stability and a large molding temperature range, and is suitable as a reinforcing material for printed circuit board substrates.

Description

A kind of Y2O3-containing fluorine-free low-dielectric glass fiber and its preparation method

technical field

The invention belongs to the technical field of glass fibers, and in particular relates to a fluorine-free glass fiber with low dielectric constant and low loss, which is especially suitable for the production field of printed circuit boards.

Background technique

Glass fiber is a new type of functional material and structural material among inorganic non-metallic materials. Because it has a series of excellent properties such as high temperature resistance, corrosion resistance, high strength, low specific gravity, low moisture absorption, small extension and good insulation, it has been widely used in electronics, communications, nuclear energy, aviation, aerospace, weapons, ships and oceans. High-tech industries such as development and genetic engineering have become indispensable high-tech materials for sustainable development in the 21st century.

Glass fiber has a series of advantages such as high temperature resistance and good electrical insulation performance. It is widely used in electrical insulation. It can improve the performance of electrical products, improve product quality, and save a lot of metal materials. It is still a technological revolution in the motor industry and An important new material for technological innovation. Among them, low-dielectric glass fiber is used as the strengthening material of PCB, and the optimization of its dielectric property is of great significance to all aspects of modern high-tech fields.

At present, the widely used low-dielectric glass fiber is E glass fiber, and its composition is: SiO ₂ : 52%~56%, B ₂ O ₃ : 5%~10%, Al ₂ O ₃ : 12%~16%, CaO: 16%~25%, MgO: 0~5%, _Na2O + _K2O : 0~1%. E glass fiber has good water resistance and processability, and the price is low, but its dielectric constant is relatively high, generally greater than 6.5, and the dielectric loss is relatively large, generally higher than 10 ^-3 , which is difficult to meet the high density of PCB boards and high-speed information processing. In this regard, experts have developed a new type of glass fiber——D glass fiber. The dielectric constant of this fiber can reach about 4.1, and the loss can be as low as 8×10 ^-4 . Limitations: First, compared with E glass fiber, its SiO ₂ content is higher, resulting in higher glass melting temperature, poor melting, easy to produce defects such as bubbles in production, resulting in difficulty in drawing, and in the textile process It is easy to cause problems such as broken wires; secondly, the multilayer substrate reinforced by D glass fiber has high hardness and poor drilling performance, which is not conducive to subsequent production and processing; moreover, its water resistance is poor, and it is not firmly bonded to the resin substrate, so it is easy to Peeling occurs.

For the above existing situation, many experts and scholars at home and abroad have also done a lot of research.

Chinese patent 201110402635.0 discloses a low-dielectric glass and glass fiber for electronic applications, its components (by weight %) include: SiO ₂ : 60~68, B ₂ O ₃ : 7~12, Al ₂ O ₃ : 9~15, CaO: 0~4, MgO: 8~15, Na2O: 0~1, _K2O : 0~1, _Li2O : 0 _~ 2, _{Fe2O3 :} 0~1 , F ₂ : 0~1, TiO ₂ : 0~2, other components: 0~5. The dielectric constant of the glass is 5.6-6.7, and the molding temperature is between 1320-1370. Its composition is similar to that of E glass fiber, but its dielectric and molding properties are better than that of E glass fiber.

Patent 200780048402.7 discloses a low dielectric glass fiber, the glass composition (by weight %) includes: SiO ₂ : 52~60, B ₂ O ₃ : 20~30, Al ₂ O ₃ : 11~16, CaO : 4~8, and basically does not contain MgO, Na ₂ O, K ₂ O, Li ₂ O, TiO ₂ , but can contain up to 2 F ₂ . Its dielectric constant is less than or equal to 5 at 1MHz, 10GHz and 18GHz, and its dielectric loss is lower than 5×10 ^-4 , 32×10 ^-4 and 30×10 ^-4 at 1MHz, 10GHz and 18GHz respectively. Compared with E glass fiber, the performance is greatly improved, and the dielectric loss is equivalent to D glass fiber.

Patent 201110319058.9 discloses a low-dielectric glass and glass fiber for electronic applications, its components (by weight %) include: SiO ₂ : 48~58, B ₂ O ₃ : 18~28, Al ₂ O ₃ : 10~18, CaO: 0~6, MgO: 0.5~8, Na ₂ O, K ₂ O and Li ₂ O: 0~1, Fe ₂ O ₃ : 0~0.5, F ₂ : 0~3, TiO ₂ : 0~0.45, Y ₂ O ₃ : 0.5~8, CeO ₂ : 0.2~0.6. Its dielectric constant can reach 4.1~4.5 at 1MHz, and its dielectric loss can reach 7×10 ^-4 ~9×10 ^-4 at 1MHz. However, its composition contains F, which will cause serious harm to the environment and is not conducive to environmentally friendly development.

Patent 02810477.3 discloses a low-dielectric glass fiber composition, P ₂ O ₅ is its essential component, so that the dielectric loss of the glass fiber at high frequencies is significantly reduced at lower frequencies, but its dielectric constant changes in the process of frequency Always around 5.

Patent US6309990 discloses a low-dielectric glass fiber with a dielectric constant of 4.2-4.8, a dielectric loss of 5-9×10 ^-4 and a molding temperature of 1300-1360 at a frequency of 1 MHz. The dielectric properties of the glass fiber are similar to those of the D glass fiber, the water resistance is also better, and the forming ability is improved compared with the D glass fiber.

Contents of the invention

However, the above-mentioned patents have problems such as high molding temperature or substances that are not conducive to glass fiber molding. In view of this, the technical problem to be solved by the present invention is to provide a low-dielectric glass fiber. The glass fiber provided by the present invention has good manufacturability And operability and lower dielectric constant and dielectric loss.

The invention provides a glass fiber with excellent dielectric properties, which is made of the following molar percentages of raw materials: SiO ₂ 56%~64%, B ₂ O ₃ 16%~20%, Al ₂ O ₃ 8%~14% %, Na ₂ O 0.5%~1%, CaO 8%~12%, Y ₂ O ₃ 0.5%~8%.

Preferably, it includes: 57%~63% SiO ₂ .

Preferably, it includes: 17%~19% of B ₂ O ₃ .

Preferably, include: 9%~12% Al ₂ O ₃ .

Preferably, include: 9%~11% CaO.

Preferably, include: Na ₂ O <0.8%.

Preferably, it includes: the content of Y ₂ O ₃ is lower than 4.5%.

The main technical means in the present invention is to introduce yttrium oxide (Y ₂ O ₃ ) into the glass composition, and the introduction of Y ₂ O ₃ can improve the dielectric properties of the glass. Since the space charge polarization is mainly affected by the degree of polymerization of the glass network structure, the greater the degree of network structure, the greater the steric resistance of charge movement, the smaller the polarization, and the improvement of dielectric properties; similarly, if the degree of network polymerization Reduced, increased charge movement leads to increased polarization, which has a bad effect on dielectric properties. The rare earth element Y ₂ O ₃ has a large field strength, and a small amount of addition can play a role in linking non-bridging oxygen to repair the network; in addition, the rare earth element Y ₂ O ₃ has a large ionic radius, if excessive addition of Y ₂ O ₃ will play a role in destroying the glass network structure. Based on the above analysis, it can be seen that when the content of Y ₂ O ₃ is small, its network repairing effect plays a major role, on the one hand, it can greatly reduce the polarization of non-bridging oxygen, on the other hand, it can make the network structure of the glass denser and inhibit The movement of alkali metals and alkaline earth metals, so a small amount of rare earth element Y ₂ O ₃ can improve the dielectric properties of the glass. If too much Y ₂ O ₃ is introduced, it will have the opposite effect, so Y ₂ O ₃ should be added in an appropriate amount. In the present invention, the Y ₂ O ₃ content is optimally limited to less than 4.5%.

As the main network former of glass, SiO ₂ has an important influence on the properties of glass. It has a high bond strength, and it is not easy to generate polarization under the action of an external electric field, and it is not easy to generate conductance and relaxation loss. The high SiO ₂ content enhances its skeleton effect, and the increase of SiO ₂ content has a significant effect on reducing its dielectric constant and dielectric loss. However, as SiO ₂ strengthens the glass network skeleton, the high-temperature viscosity of the glass will increase, making it difficult to draw the glass and increasing the difficulty of industrial production. Therefore, the amount of SiO ₂ added should be within an appropriate range. In order to meet the requirements of glass dielectric properties and production requirements, the optimum _SiO2 content in the present invention is limited to 57%~63%. .

_B2O3 is the most widely used glass former among glasses other than _SiO2 , which can form glass _alone . Its biggest feature is that it can improve the performance of the glass and has a good fluxing effect. The addition of B ₂ O ₃ introduces B ³⁺ to form BO. The bond energy of this bond is larger than that of Si-O bond, which can stabilize the glass network structure and limit the polarization of oxygen ions in glass species. Therefore, adding B ₂ O ₃ in an appropriate amount can optimize the dielectric properties of the glass. In addition, B ₂ O ₃ has a fluxing effect in the glass species, which can reduce the high-temperature viscosity of the glass, save costs and facilitate production. However, B ₂ O ₃ is volatile and will pollute the environment, so the dosage should be strictly controlled in the production process. In the present invention, the B ₂ O ₃ content is optimally limited to 17%~19%.

The addition of Al ₂ O ₃ can effectively suppress the phase separation of glass. In addition, the Al ₂ O ₃ added glass can exist as a network intermediate, and the addition of Al ₂ O ₃ will affect the network structure of the glass. Although Al ₂ O ₃ can play a role in linking and breaking the network in multi-component glasses, the Al-O bond energy is weaker than the Si-O bond energy, so the loss caused by free oxygen may increase. In addition, Al ₂ O ₃ It exists in the glass network in the form of [AlO ₄ ], and its increase will weaken the combination of alkali metal ions and the network, so the dielectric loss will increase significantly. Therefore, it is necessary to control an appropriate range when considering the addition of Al ₂ O ₃ . In the present invention, the optimal limit of Al ₂ O ₃ content is 9%~12%.

The addition of alkali metal oxides (Na ₂ O) and alkaline earth metal oxides (CaO) will greatly reduce the high-temperature viscosity of the glass, and the addition of CaO will greatly reduce the phase separation tendency of the glass. However, both alkali metals and alkaline earth metals will destroy the dielectric properties of the glass, so the addition of alkali metals and alkaline earth metals requires an appropriate amount. In the present invention, the Na ₂ O content is optimally limited to <0.8%. In the present invention, the CaO content is optimally limited to 9% to 11%.

The components of the low-dielectric glass fiber of the present invention do not contain F (F means F-containing component), Fe (Fe means Fe-containing component), Li ₂ O, and K ₂ O. It does not substantially contain MgO and substantially does not contain TiO ₂ . The simplification of the types of alkali metals and alkaline earth metals contained therein makes it easier to control the optimum content of suitable alkali metals and alkaline earth metals. The low-dielectric glass fiber of the invention does not contain F, and can protect the environment. No TiO ₂ is added to the components of the present invention, which can reduce the possibility of crystallization of the glass.

The preparation method of fluorine-free low-dielectric glass fiber of the present invention comprises the following steps:

The first step: convert the molar ratio of each component of the glass fiber into mass and weigh it, and mix the weighed raw materials for 1 to 2 hours until uniform;

Step 2: Melt the homogeneously mixed raw materials in a kiln at 1500-1550°C for 2-4 hours, and keep warm at this temperature for 3-4 hours to clarify and homogenize;

Step 3: The clarified glass liquid flows through the pipeline in the drawing section (the temperature of the pipeline is kept above 1300°C), and the glass also flows through the platinum drain plate (the temperature of the drain plate is kept at 1240~1290°C), and the glass is drawn by the wire drawing machine. The fibers are bundled to obtain fluorine-free low dielectric constant and low dielectric loss glass fibers.

Detailed ways:

The invention will be illustrated by the following series of specific examples, however, it will be understood by those skilled in the art that many other embodiments are contemplated in accordance with the principles of the invention.

Embodiment 1~6

The raw material of the present invention can be made into glass or glass fiber. The method of preparing glass is to cast and anneal the glass liquid formed by melting the raw materials; the method of preparing glass fiber is to draw the prepared glass liquid on the basis of the wire drawing process. Since some test items cannot directly use glass fiber, in order to test various properties of glass fiber more conveniently, glass with the same formula is prepared for testing.

Remark:

1) Dielectric properties: Use Keysight E4990A precision impedance analyzer to measure the dielectric constant and dielectric loss of the sample at a frequency of 1MHz;

2) Glass forming temperature: use BROOKFIELD high-temperature viscometer to detect, take the temperature value corresponding to Lg3.0 as the glass fiber forming temperature;

3) Liquidus temperature: Use a TGA/DSC 1-1600HT differential scanning calorimeter to measure the liquidus temperature of the sample.

According to the glass formula (Table 1), accurately weigh 100g of each raw material with an analytical balance, mix the weighed raw materials evenly, put them into an alumina crucible, place them in a lift-type high-temperature resistance furnace, melt them at 1500-1550°C, and Keep warm for more than 3 hours to make the glass liquid fully clear and uniform; stir once every half an hour to discharge the bubbles in the glass liquid and make the chemical composition of each area in the glass liquid uniform; quickly remove the uniformly melted glass liquid and pour it into a special graphite mold After being cooled and formed, it is then placed in a muffle furnace and annealed at 550-640°C for 1-3 hours, then the annealing furnace is powered off to stop heating, and the glass sample is cooled to room temperature with the furnace. Precisely cut the annealed glass sample into 10×10×2mm blocks and polish the surface, and use an impedance analyzer to test the dielectric properties of the sample; grind the remaining glass sample, pass through a 150-mesh sieve, and conduct a thermal analysis test .

During the thermal performance test, a small amount of powder is placed in a miniature alumina crucible, then placed in a platinum crucible with a cover, placed on the sample holder of the instrument, and the sample is heated and tested according to the preset program, and finally the characteristics of the glass sample are measured Temperature points (including: glass transition temperature, crystallization temperature and liquidus temperature).

When testing the dielectric properties, clean the surface of the block sample with alcohol, then dry it in a drying oven at 100°C for 1 hour, test the sample with a Keysight E4990A precision impedance analyzer, and test the dielectric properties of the glass at room temperature and a vibration frequency of 1MHz. The dielectric constant and dielectric loss, and directly calculate the dielectric constant and dielectric loss value of the glass block through the soft armor.

Table 1: Component list of each glass sample in Examples 1-6

Carry out performance test to above-mentioned glass, the result sees table 2:

It can be seen from Table 2 that the fluorine-free low-dielectric glass fiber provided by the embodiment of the present invention has good dielectric properties, and its dielectric constant can reach 4.12 at its best, comparable to D glass. Its glass fiber molding temperature is low, and its molding temperature is lower than 1295 ° C, which makes up for the problem that D glass cannot be used in production due to its high molding temperature. The glass fiber in the present invention conforms to the drawing conditions of industrialization at the present stage, and the ΔT is greater than 105° C., which is easy to form the glass fiber.

From the above analysis, it can be seen that the addition of Y ₂ O ₃ has a better effect on the dielectric properties of the glass. The addition of Y ₂ O ₃ can greatly reduce the dielectric constant and dielectric loss of the glass. However, when the amount of Y ₂ O ₃ is too much, since the larger radius of Y ₂ O ₃ will cause damage to the structure of the glass, it needs to be added in an appropriate amount.

From the above comparative analysis, it can be seen that the present invention can simultaneously possess excellent dielectric properties and conditions that can facilitate production. It can be widely used as a reinforcing material in printed circuit boards.

It should be pointed out that the above-mentioned embodiments are only examples for clearly illustrating the present application, but are not intended to limit the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or variations derived therefrom are still within the scope of protection of the present application.

Claims (10)

1. A fluorine-free low dielectric constant and low dielectric loss glass fiber, characterized in that it is made of the following molar percentage raw materials: SiO ₂ 56%~64%, B ₂ O ₃ 16%~20%, Al ₂ O ₃ 8%~12%, Na ₂ O 0.5%~1%, CaO 8%~12%, Y ₂ O ₃ 0.5%~8%. 2 . The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 1 , characterized in that, by mole, it contains: 57%~63% SiO ₂ . 3. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 1-2, characterized in that, in terms of moles, it includes: 17%~19% B ₂ O ₃ . 4. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 1-3, characterized in that, in terms of moles, it includes: 9%~11% Al ₂ O ₃ , and SiO ₂ / B ₂ O ₃ is 2.8~4, B ₂ O ₃ /Al ₂ O ₃ is 1.3~2.5. 5. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claims 1-4, characterized in that the fluorine-free, low dielectric constant and low dielectric loss glass fiber comprises: 9% to 11% CaO in moles. 6. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 1-5, characterized in that, in terms of moles, it includes: Na ₂ O <0.8%, and CaO/Na ₂ O >11 . 7. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 1-6, characterized in that it contains: Y ₂ O ₃ content is lower than 4.5%; Contains F (F means containing F component), does not contain Fe at all (Fe means contains Fe component), does not contain Li ₂ O at all, does not contain K ₂ O basically, does not contain MgO basically, does not contain TiO ₂ basically. 8. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 1-7, wherein the preparation method comprises the following steps: Convert the molar ratio of each component of the glass fiber into mass, weigh the raw materials, and mix the weighed raw materials for 1 to 3 hours until uniform; Melting the mixed raw materials in step (1) at 1500~1550°C for 2~4 hours; Cooling the melted, clarified and homogeneous molten glass in step (2) to the drawing temperature range, and drawing to obtain fluorine-free, low dielectric constant and loss glass fibers. 9. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claim 7, characterized in that, the sample used for dielectric performance testing is made by melting, clarifying and homogenizing in step (2) of claim 8 The molten glass is cast in a mould. 10. The fluorine-free low dielectric constant and low dielectric loss glass fiber according to claims 1-7, characterized in that the drawing temperature range is greater than 105°C, and the dielectric constant and dielectric loss at 1MHz are 4.12~ 4.67 and 5.1×10 ^-3 ~7.7×10 ^-3 .