CN100489033C - Thermostable composition of low dielectric loss and its preparing process - Google Patents

Abstract

The invention discloses a heat-proof composition with low-dielectric consumption, which consists of 40-99.9% cyanate and 0.1-60% barium titanate, wherein the grain size of barium titanate is between 150 and 600 order. The making method comprises the following steps: blending cyanate and barium titanate to fuse at 100 deg.c; heating to 130-160 deg.c to presolidify until the barium titanate doesn't sediment obviously; obtaining the composition with dielectric constant between 2 and 6 adjustably through changing the content of barium titanate , physical chemical property and subsequent disposing technique of composition.

Description

A heat-resistant composition with low dielectric loss and its preparation method

technical field

The invention relates to a heat-resistant organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss, belonging to the technical field of dielectric composite material preparation.

Background technique

In order to meet the requirements of electrical performance design and use, modern industry has an increasing demand for heat-resistant materials with adjustable dielectric constant and low dielectric loss. Since it is difficult to meet the requirements of manufacturability and performance for a single variety of materials, the development of organic/inorganic composite materials that have both the excellent mechanical properties and manufacturability of organic polymers and the excellent dielectric properties of inorganic substances has become the current focus in the field of dielectric materials. Research hotspots.

In recent years, there have been many studies on organic/inorganic composite dielectric materials. The selected organic polymer matrices mainly include polyvinylidene fluoride, vinylidene fluoride (VDF)-trifluoroethylene (TrFE) copolymer, polytetrafluoroethylene, poly Imide resin and epoxy resin, etc. The ceramics used are generally barium titanate (BaTiO ₃ ), lead titanate (PbTiO ₃ ) and lead zirconate titanate. For example, Dong Lijie prepared PbTiO ₃ /PVDF composite material by hot pressing method. When the mass percentage of PbTiO ₃ is 70%, the dielectric constant of the composite material is the largest (77.6), and the dielectric loss is about 0.1 at this time; When vinyl fluoride-trifluoroethylene was used as the resin matrix, it was found that the dielectric constants of the two composite materials were 9 and 34 when the volume fraction of PbTiO ₃ was 21 and 40%, respectively; Zhu Baoku et al. coupled polyamic acid solution with silane Barium titanate (BaTiO ₃ ) particles with a particle size of 100nm were prepared by solution blending to prepare a dielectric composite material. When the volume fraction of BaTiO ₃ particles reaches 50%, the dielectric constant can reach 35 and the dielectric loss is 0.0082 ( 10kHz), and it is stable in a considerable range of temperature and frequency; Kuo et al. added BaTiO ₃ to epoxy resin to obtain a composite material with a dielectric constant of around 50.

It can be seen from the existing literature that (1) the particle size of the selected inorganic fillers is small (more than ten microns to nanometers), and the cost of raw materials is relatively high; (2) the dielectric loss of the obtained composite material is relatively high (average higher than the resin matrix), which is unfavorable for the development of high-stability products; (3) the simple organic/inorganic binary compound method cannot be used to obtain materials with both adjustable dielectric constant and low dielectric loss characteristics, and it is necessary to assist in doping miscellaneous means.

Cyanate ester (CE) resin is a kind of high-performance thermosetting resin with excellent comprehensive properties developed in the late 1960s. Compared with epoxy resin, bismaleimide and phenolic resin, which are widely used at present, CE has more excellent dielectric properties, which is manifested in extremely low dielectric loss (0.002-0.006), and the dielectric properties have no effect on temperature and Changes in the frequency of electromagnetic waves show a unique stability. Compared with other engineering thermoplastic resins (such as polyimide resin, polyphenylene ether, polybenzocyclobutene resin, etc.), CE resin has excellent manufacturability, low cost and higher cost performance. In cutting-edge fields including microelectronics, aviation, aerospace and other industries, especially in the occasions that require high dielectric properties, hygrothermal properties and mechanical properties, CE is the most competitive resin variety. Therefore, the applicant considered to prepare a new heat-resistant composition with low dielectric loss based on cyanate resin.

Contents of the invention

The purpose of the present invention is to provide a heat-resistant composition with low dielectric loss and adjustable dielectric constant; and to provide a preparation method for the heat-resistant composition.

In order to achieve the above object, the technical solution adopted by the present invention is: a heat-resistant composition with low dielectric loss, which is composed of 40-99.9% cyanate and 0.1-60% barium titanate by weight. The particle size of barium titanate is between 600 mesh and 150 mesh.

In the above technical scheme, the barium titanate is selected from barium titanate without surface treatment, barium titanate with surface treatment or a combination thereof, and the surface treatment is to dissolve the coupling agent in an organic solution, and then pour Put in the pre-dried barium titanate, stir evenly with a high-speed homogeneous mixer, let it air, and dry it to obtain surface-treated barium titanate.

The cyanate is selected from one of bisphenol A type, bisphenol E type, bisphenol F type, bisphenol M type, dicyclopentadiene type bisphenol type or a combination thereof. Cyanate resin products have been commercialized. Therefore, any commercial cyanate resin products can be used for the above-mentioned types of cyanate resins.

The preparation method of the low dielectric loss heat-resistant composition of the present invention is to mix cyanate ester and barium titanate according to the weight ratio, melt at 100°C, and then heat up to 130-160°C for pre-curing, until titanium There is no obvious precipitation of barium acid, that is, the heat-resistant composition with low dielectric loss is obtained.

After pre-curing, the barium titanate can be evenly distributed in the cyanate resin, and then it can be cured to obtain the desired heat-resistant material.

The coupling agent is a silane coupling agent or a titanate coupling agent.

Wherein, the pre-curing time decreases with the increase of the barium titanate content or the increase of the pre-curing temperature, and the preferred solution is that the pre-curing time is between 0.5 and 8 hours.

Due to the use of the above-mentioned technical solutions, the present invention has the following advantages compared with the prior art:

1. The present invention uses cyanate ester with excellent dielectric properties as matrix resin to form a binary composite organic/inorganic composition with barium titanate, which not only has a high dielectric constant but also can be adjusted (2-16) , and the dielectric loss is extremely low (<0.002);

2. The barium titanate of the present invention adopts a particle size between 600 mesh and 150 mesh. In the prior art, the barium titanate used in the binary composition is nanoscale. The present invention adopts the larger barium titanate particle size, The composition with low dielectric loss is obtained, because the BaTiO ₃ with larger particle size has obvious hindering effect on the movement of CE molecules, and this hindering effect increases with the increase of BaTiO ₃ content, resulting in a dielectric Electric loss is significantly lower than pure CE resin, and decreases with the increase of _BaTiO3 content, which is unexpected by those skilled in the art. Therefore, the present invention overcomes the prejudice and has creativity; meanwhile, because the particle size of _BaTiO3 is relatively small Large (between 600 mesh and 150 mesh), the composition also has the characteristics of low cost and easy availability of raw materials.

3. The present invention adopts a simple casting method, uses cyanate ester as the resin matrix, and _BaTiO3 as the functional filler, and obtains a heat-resistant organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss. The preparation process is simple.

Description of drawings

Accompanying drawing 1 is the relation graph of the dielectric constant and the frequency of the composition of the embodiment of the present invention;

Accompanying drawing 2 is the dielectric constant of the composition of the present invention embodiment 2 to embodiment 7 and comparative example 1 and _BaTiO Content relational graph (under 1KHz);

Accompanying drawing 3 is the relationship curve (under 1KHz) of dielectric loss tangent and BaTiO3 content of the composition of embodiment 2 to embodiment 7 of the present invention and comparative example 1.

Detailed ways

The present invention will be further described below in conjunction with embodiment:

Embodiment one:

According to A1 listed in Table 1, bisphenol A type dicyanate (BADCy) and BaTiO ₃ (400 mesh) were mixed according to the proportion, and the mixture was heated and melted in an oil bath at 100°C, and then heated to 150°C for pre-curing 4 hours, BaTiO ₃ has no obvious sedimentation, that is, an organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss is obtained.

Inject the composition into a preheated (150°C) mold, degas it in a vacuum oven at 100-105°C for 30 minutes, and cure it according to the process of 160°C/2h+180°C/2h+200°C/2h , according to the process of 230 ℃ / 5h post-treatment, that is, get BADCy/BaTiO ₃ composite material. Test the dielectric constant in the range of 1 Hz to 10 GHz, and its value is shown in Figure 1. It can be seen that the dielectric constant of the material is stable over the entire test frequency range.

Embodiment two～seven:

According to the formulas A1 to A7 listed in Table 1, mix bisphenol A dicyanate (BADCy) and BaTiO ₃ (400 mesh) according to the proportion, heat and melt the mixture in an oil bath at 100°C, and then heat up to 150°C Pre-curing for a certain period of time until BaTiO ₃ has no obvious sedimentation (as shown in Table 1), an organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss can be obtained.

Inject the composition into a preheated (150°C) mold, degas it in a vacuum oven at 100-105°C for 30 minutes, and cure it according to the process of 160°C/2h+180°C/2h+200°C/2h. According to the process of 230 ℃ / 5h for post-treatment, the BADCy/BaTiO ₃ composite material is obtained. The dielectric properties of each sample at 1KHz are shown in Figure 2 and Figure 3 . It can be seen that the dielectric constant of the material increases with the increase of the content of BaTiO ₃ in the system. When the content of BaTiO ₃ changes in the range of 0-60wt%, the dielectric constant of the material is adjustable in the range of 2-16. In addition, the dielectric loss of the composite is significantly lower than that of the pure CE resin.

Table 1 Formulation and pre-curing time at 150°

Comparative example 1

Heat and melt BADCy in an oil bath at 100°C, heat up to 150°C for pre-curing for 4 hours, inject it into a preheated (150°C) mold, degas it in a vacuum oven at 100-105°C for 30 minutes, press 160 ℃/2h+180℃/2h+200℃/2h for curing, followed by 230℃/5h for post-treatment to obtain pure BADCy cured resin. Its dielectric properties at 1KHz are shown in Figure 2 and Figure 3 .

Embodiment eight to nine:

Mix 35g of BADCy and 15g of BaTiO ₃ (400 mesh), heat and melt the mixture in an oil bath at 100°C, then raise the temperature to 130°C for 8 hours to pre-cure until BaTiO ₃ has no obvious sedimentation, and then obtain a dielectric constant adjustable and low dielectric Lost organic/inorganic binary composition.

The composition is injected into a mold preheated at 150°C, degassed in a vacuum oven at 100-105°C for 30 minutes, and cured according to the process of 160°C/2h+180°C/2h+200°C/2h, and finally Post-treatment is carried out according to the process of 220°C/1h or 220°C/1h+230°C/4h respectively. The dielectric properties of the obtained samples are shown in Table 2. It can be seen that when the curing degree of the material is about 100%, the dielectric constant of the material can be realized by changing the post-treatment process of the material. In addition, the dielectric loss tangent of the material decreases further with subsequent processing.

Table 2 Effect of post-treatment process on dielectric properties of materials (under 1KHz)

Embodiment ten to eleven:

Dilute 0.4 grams of silane coupling agent γ-aminopropyltriethoxysilane (KH-550) with 5 grams of acetone, then add 20 grams of BaTiO ₃ (400 mesh), mix evenly and let it dry, and wait for most of the acetone to volatilize , baked at 70°C for 6h, the treated BaTiO ₃ with Si-O-Si chemical bonds on the surface was obtained.

Mix 25g of BADCy and 20g of surface-treated BaTiO ₃ (400 mesh) thoroughly and evenly. After the mixture is heated and melted in an oil bath at 100°C, the temperature is raised to 150°C for pre-curing for 1 hour, and the dielectric constant and low dielectric constant are obtained. Organic/inorganic binary compositions for electrical losses.

Inject the composition into a mold preheated at 150°C, degas it in a vacuum oven at 100-105°C for 30 minutes, and cure it according to the process of 160°C/2h+180°C/2h+200°C/2h. 220°C/1h or 220°C/1h+230°C/4h process post-treatment to prepare samples. The dielectric properties of the obtained samples are shown in Table 3. It can be seen that when the curing degree of the material is about 100%, the dielectric constant of the material can be realized by changing the physical and chemical properties of the surface of the material, that is, the coupling agent can significantly improve the dispersion effect of _BaTiO3 particles in the cyanate matrix , thereby increasing the dielectric constant of the material, while the dielectric loss tangent of the material is not affected.

Table 3 Effect of BaTiO ₃ (400 mesh) surface treatment on dielectric properties of materials

Embodiment 12:

Mix 20g of BADCy, 10g of bisphenol E cyanate and 25g of BaTiO ₃ (600 mesh), heat and melt the mixture in an oil bath at 100°C, then raise the temperature to 160°C for pre-curing for 1.5h until the BaTiO ₃ has no obvious sedimentation, and you can get An organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss. Inject the composition into a preheated (150°C) mold, degas it in a vacuum oven at 100-105°C for 30 minutes, and cure it according to the process of 160°C/2h+180°C/2h+200°C/2h , according to the process of 230 ℃ / 5h post-treatment, that is, get BADCy/BaTiO ₃ composite material. The dielectric constant and dielectric loss tangent of the obtained sample at 1KHz were 10.0573 and 0.0015, respectively.

Embodiment thirteen:

Dissolve 0.4 g of titanate coupling agent tris(dioctylpyrophosphoryloxy) isopropyl titanate with 5 g of isopropyl alcohol, then add 20 g of BaTiO ₃ (150 mesh), mix evenly, and let it dry , after most of the isopropyl alcohol volatilized, it was baked at 85° C. for 6 hours to obtain surface-treated BaTiO ₃ (150 mesh).

Mix 20g of dicyclopentadiene bisphenol-type cyanate, 15g of bisphenol E-type cyanate and 15g of surface-treated BaTiO ₃ (150 mesh), heat and melt the mixture in an oil bath at 100°C, then heat up to 140°C Pre-curing for 5 hours until BaTiO ₃ has no obvious sedimentation, that is, an organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss is obtained.

Inject the composition into a mold preheated at 150°C, degas it in a vacuum oven at 100-105°C for 30 minutes, and cure it according to the process of 160°C/2h+180°C/2h+200°C/2h, then press 220 ℃/1h+230℃/4h process post-treatment to prepare samples. The dielectric constant and dielectric loss tangent of the obtained sample at 1KHz were 8.4573 and 0.002, respectively.

Embodiment 14:

Mix 30g of bisphenol A dicyanate (BADCy) and 10g of BaTiO ₃ (240 mesh) treated with silane coupling agent KH-550, heat and melt the mixture in an oil bath at 100°C, then heat up to 150°C for pre-curing After 4 hours, BaTiO ₃ did not settle significantly, that is, an organic/inorganic binary composition with adjustable dielectric constant and low dielectric loss was obtained.

Inject the composition into a preheated (150°C) mold, degas it in a vacuum oven at 100-105°C for 30 minutes, and cure it according to the process of 160°C/2h+180°C/2h+200°C/2h , according to the process of 230 ℃ / 5h post-treatment, that is, get BADCy/BaTiO ₃ composite material. The dielectric constant and dielectric loss tangent of the obtained sample at 1KHz were 8.4573 and 0.001, respectively.

Claims (6)

1. A heat-resistant composition with low dielectric loss, characterized in that: by weight, it consists of 40-99.9% cyanate and 0.1-60% barium titanate, and the particle size of the barium titanate is 600 between mesh and 150 mesh; the dielectric loss value of the heat-resistant composition is less than 0.002. 2. The heat-resistant composition with low dielectric loss according to claim 1, characterized in that: the barium titanate is selected from barium titanate without surface treatment, barium titanate with surface treatment or a combination thereof , the surface treatment is to dissolve the coupling agent in the organic solution, then pour into the pre-dried barium titanate, stir evenly with a high-speed homogeneous mixer, let it air, and dry. 3. The heat-resistant composition with low dielectric loss according to claim 1, characterized in that: the cyanate is selected from bisphenol A type, bisphenol E type, bisphenol F type, bisphenol M type, One of dicyclopentadiene type bisphenol types or a combination thereof. 4. The preparation method of the heat-resistant composition with low dielectric loss according to claim 1, characterized in that: mix cyanate ester and barium titanate according to the weight ratio, melt at 100°C, and heat up to 130- Pre-curing is performed at 160° C. until the barium titanate has no obvious sedimentation, that is, the heat-resistant composition with low dielectric loss is obtained. 5. The method for preparing the heat-resistant composition with low dielectric loss according to claim 4, characterized in that: the barium titanate is selected from barium titanate without surface treatment, barium titanate with surface treatment or Its composition, the surface treatment is to dissolve the coupling agent in the organic solution, then pour into the pre-dried barium titanate, stir evenly with a high-speed homogeneous mixer, let it air, and dry; the coupling agent is Silane coupling agent or titanate coupling agent. 6. The method for preparing the heat-resistant composition with low dielectric loss according to claim 4, characterized in that: the pre-curing time is between 0.5 and 8 hours.

Images