CN114957916A - Curable resin system, insulating material, preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of insulating materials, and in particular relates to a curable resin system and an insulating material and a preparation method and application thereof. The curable resin system provided by the present invention includes component A and component B, wherein the component A is an epoxy resin, and the component B is a curing agent; the epoxy resin includes bisphenol A epoxy resin, Novolac epoxy resin and isocyanate modified epoxy resin; the curing agent includes one or more of dihydrodiamine and diaminodiphenyl sulfone, and the insulating material provided by the present invention includes a curable resin system, a filler and reinforcement materials. The results of the examples show that the insulating material prepared by using the curable resin system provided by the present invention has good toughness, good heat resistance, a glass transition temperature greater than 150° C., a 5% thermal decomposition temperature greater than 310° C., and a cost reduction of more than 30%. It has the characteristics of strong dielectric properties.

Description

Curable resin system and insulating material, preparation method and application thereof

technical field

The invention belongs to the technical field of insulating materials, and in particular relates to a curable resin system and an insulating material and a preparation method and application thereof.

Background technique

Electronic insulation board is a kind of material with high performance requirements in insulation board, which is mainly reflected in the requirements for dielectric properties and heat resistance. The electronic insulating board is mainly composed of a matrix and a reinforcing material. The commonly used reinforcing material is glass fiber. Glass fiber has good insulation, strong heat resistance, good corrosion resistance and high mechanical strength, but high brittleness. When making electronic insulating boards, it is necessary to dilute the resin system to a lower viscosity first, so that the resin system can easily penetrate between glass fibers and infiltrate the glass fibers, and then through the processes of baking, cutting, lamination and curing, the molding is formed. The rear electronic insulation board has very high strength. Among them, the glass transition temperature of the resin cured product will directly affect the applicable scenarios of the electronic insulating board, and the glass transition temperature of the general epoxy resin cured product is between 110 and 115 ℃, but some application scenarios Such as generator sets and high-speed rail tops, etc., the glass transition temperature of insulating materials is required to be not lower than 135 °C.

In the existing insulating material system, an alicyclic diamine cross-linking agent is added to increase the glass transition temperature, but the alicyclic diamine cross-linking agent reacts too quickly during the baking process, which is not suitable for the processing characteristics of electronic insulating boards. The baking in the middle cannot control the gel time of the semi-cured product, which is not conducive to the control of the finished product in the hot pressing forming stage.

There are many reports on the insulation material system in the composite material industry, but there are always defects in heat resistance, which cannot meet the requirements of high temperature use during long-term operation; some researchers have used oxazine structure or multifunctional in the insulation material system. Epoxy resin improves the crosslinking density of the material and increases the glass transition temperature of the material to a certain extent, but the obtained material is too brittle, especially in the environment of low temperature or frequent alternating hot and cold.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a curable resin system and an insulating material and a preparation method and application thereof. The insulating material prepared by the curable resin system provided by the present invention has good toughness, good heat resistance, and a glass transition temperature greater than 150° C. 5% thermal decomposition temperature is greater than 310 ℃, and the cost is reduced by more than 30%.

In order to achieve the above object, the present invention provides the following technical solutions:

The present invention provides a curable resin system, including component A and component B, wherein the component A is an epoxy resin, and the component B is a curing agent; the epoxy resin includes a bisphenol A-type ring Oxygen resin, phenolic epoxy resin and isocyanate modified epoxy resin; the curing agent includes one or more of dihydrodiamine and diaminodiphenylsulfone.

Preferably, the mass ratio of the epoxy resin and the curing agent is 85-95:5-10.

Preferably, the content of bisphenol A epoxy resin in the epoxy resin is not less than 40wt%, the content of phenolic epoxy resin is not less than 20wt%, and the content of isocyanate modified epoxy resin is not less than 10wt% %.

Preferably, when the curing agent includes dihydrodiamine and diaminodiphenyl sulfone, the content of dihydrodiamine in the curing agent is not less than 90wt%, and the content of diaminodiphenylsulfone is not less than 5wt% .

Preferably, the epoxy equivalent of the bisphenol A epoxy resin is 450-500 g/eq, the epoxy equivalent of the novolac epoxy resin is 200-230 g/eq, and the epoxy equivalent of the isocyanate-modified epoxy resin is 200-230 g/eq. is 270-310 g/eq; the active hydrogen equivalent of the dihydrodiamine is 15-25 g/eq, and the active hydrogen equivalent of diaminodiphenyl sulfone is 60-65 g/eq.

Preferably, the structural formula of the bisphenol A epoxy resin is:

Preferably, the structural formula of the novolac epoxy resin is:

Preferably, the structural formula of the isocyanate-modified epoxy resin is:

Wherein, n ₁ , n ₂ and n ₃ are the degrees of polymerization of epoxy resins, and the value range of n ₁ is preferably 1-20, more preferably 3-15; the value range of n ₂ is preferably 2 ~25, more preferably 7-20; the value range of n ₃ is preferably 1-50, more preferably 10-40, and even more preferably 20-30.

The present invention also provides an insulating material, comprising a reinforcing material and an insulating resin layer coated on the surface of the reinforcing material, and the insulating resin layer is prepared from the curable resin system and the filler described in the above solution.

The present invention also provides a method for preparing the insulating material described in the above scheme, comprising the following steps:

(1) mixing epoxy resin and good solvent to obtain epoxy solution;

(2) mixing curing agent and good solvent to obtain curing agent solution;

(3) carrying out aging reaction after mixing described epoxy solution, curing agent solution and filler to obtain mixed solution;

(4) drying the mixed solution after being loaded on the reinforcing material to obtain an insulating material;

The steps (1) and (2) have no time sequence requirement.

Preferably, the temperature of the aging reaction is 45-55°C; the time of the aging reaction is not less than 5 hours.

The present invention also provides applications of the insulating material described in the above solution or the insulating material prepared by the preparation method described in the above solution in the field of insulation, fire prevention, moisture and heat resistance and ultra-high voltage.

The present invention provides a curable resin system, including component A and component B, wherein the component A is an epoxy resin, and the component B is a curing agent; the epoxy resin includes a bisphenol A-type ring Oxygen resin, phenolic epoxy resin and isocyanate modified epoxy resin; the curing agent includes one or more of dihydrodiamine and diaminodiphenylsulfone. The raw materials of the curable resin system provided by the present invention are readily available and low in cost, and the insulating material prepared by the curable resin system has good toughness, good heat resistance and high glass transition temperature.

The present invention also provides an insulating material, comprising a reinforcing material and an insulating resin layer coated on the surface of the reinforcing material, wherein the insulating resin layer is prepared from the curable resin system and the filler described in the above solution. The insulating material provided by the invention has good toughness, good heat resistance, glass transition temperature greater than 150 DEG C, 5% thermal decomposition temperature greater than 310 DEG C, cost reduction of more than 30%, and strong dielectric properties.

The present invention also provides a method for preparing the insulating material described in the above solution. The preparation method provided by the present invention constructs a novel epoxy resin on the base epoxy resin. The preparation method provided by the invention has simple steps, does not change the original process conditions, further reduces the cost on the basis of ensuring high performance, controls the cost at a lower level, and has the prospect of large-scale industrial production.

The present invention also provides applications of the insulating material described in the above solution or the insulating material prepared by the preparation method described in the above solution in the field of insulation, fire prevention, moisture and heat resistance and ultra-high voltage. The insulating material provided by the invention has good toughness and high glass transition temperature, can meet the requirements of the glass transition temperature of the insulating material in the above application scenarios, and has good applicability in the field of high-end materials.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative labor.

FIG. 1 is a process flow of the preparation method and application of the insulating material provided by the present invention.

Detailed ways

The present invention provides a curable resin system, including component A and component B, wherein the component A is an epoxy resin, and the component B is a curing agent; the epoxy resin includes a bisphenol A-type ring Oxygen resin, phenolic epoxy resin and isocyanate modified epoxy resin; the curing agent includes one or more of dihydrodiamine and diaminodiphenylsulfone.

In the present invention, the mass ratio of the epoxy resin and the curing agent is preferably 85-95:5-10, more preferably 87-93:6-9, further preferably 89-92:7-9; the The content of bisphenol A epoxy resin in the epoxy resin is preferably not less than 40wt%, more preferably 40wt% to 65wt%, further preferably 40wt% to 55wt%; the epoxy resin of the bisphenol A epoxy resin The equivalent weight is preferably 450-500g/eq, more preferably 460-490g/eq; the content of novolac epoxy resin in the epoxy resin is preferably not less than 20wt%, more preferably 20wt%-45wt%, further preferably 20wt% %～35wt%; the epoxy equivalent of the novolac epoxy resin is preferably 200～230g/eq, more preferably 210～220g/eq; the content of the isocyanate modified epoxy resin in the epoxy resin is preferably not less than 10wt%, more preferably 10wt%～30wt%, further preferably 10wt%～20wt%; the epoxy equivalent of the isocyanate modified epoxy resin is preferably 270～310g/eq, more preferably 280～ 300g/eq.

In the present invention, the structural formula of the bisphenol A epoxy resin is preferably:

The structural formula of the novolac epoxy resin is preferably:

The structural formula of the isocyanate-modified epoxy resin is preferably:

Wherein, n ₁ , n ₂ and n ₃ refer to the degree of polymerization of epoxy resin, and the value range of n ₁ is preferably 1-20, more preferably 3-15; the value range of n ₂ is preferably 2-25, more preferably 7-20; the value range of n ₃ is preferably 1-50, more preferably 10-40, and further preferably 20-30.

In the present invention, when the curing agent includes dihydrodiamine and diaminodiphenylsulfone, the content of dihydrodiamine in the curing agent is preferably not less than 90wt%, more preferably 90wt%～94wt%, It is further preferably 91wt% to 93wt%; the content of the diaminodiphenyl sulfone is preferably not less than 5wt%, more preferably 5wt% to 9wt%, further preferably 6wt% to 8wt%; The active hydrogen equivalent is preferably 15-25 g/eq, more preferably 21-23 g/eq; the active hydrogen equivalent of the diaminodiphenyl sulfone is preferably 60-65 g/eq, more preferably 62.1-63 g/eq.

In the present invention, the structural formula of described dihydrodiamine is preferably:

The structural formula of described diaminodiphenyl sulfone is preferably:

The present invention also provides an insulating material, comprising a reinforcing material and an insulating resin layer coated on the surface of the reinforcing material, and the insulating resin layer is prepared from the curable resin system and the filler described in the above solution.

In the present invention, the filler preferably comprises one or more of silicon dioxide, mica powder, silicon micropowder, aluminum hydroxide and talc; the silicon micropowder preferably comprises one of crystalline silicon micropowder and fused silicon micropowder one or more; the reinforcing material preferably includes one or more of glass fiber cloth, carbon fiber cloth and aramid fiber cloth; the glass fiber cloth is preferably 7628 glass fiber cloth. In the present invention, the insulating performance of the material can be improved by adding the non-metal oxide, and the relative tracking index of the material can be improved by adding the metal hydroxide.

The present invention also provides a method for preparing the insulating material described in the above scheme, comprising the following steps:

(1) mixing epoxy resin and good solvent to obtain epoxy solution;

(2) mixing curing agent and good solvent to obtain curing agent solution;

(3) carrying out aging reaction after mixing described epoxy solution, curing agent solution and filler to obtain mixed solution;

(4) drying the mixed solution after being loaded on the reinforcing material to obtain an insulating material;

The steps (1) and (2) have no time sequence requirement.

In the present invention, epoxy resin and good solvent are mixed to obtain epoxy solution. In the present invention, the good solvent of the epoxy resin preferably includes one or more of 2-butanone (MEK) and propylene glycol methyl ether; the concentration of the epoxy solution is preferably not more than 90wt%, more preferably It is 70wt% to 85wt%.

In the present invention, the curing agent and the good solvent are mixed to obtain the curing agent solution. In the present invention, the good solvent of the curing agent preferably includes one or more of propylene glycol methyl ether acetate (PMA) and propylene glycol methyl ether; the concentration of the curing agent solution is preferably 5wt% to 15wt%, more It is preferably 7.5 wt % to 12 wt %.

After the epoxy solution and the curing agent solution are obtained, in the present invention, the epoxy solution, the curing agent solution and the filler are mixed and then subjected to an aging reaction to obtain a mixed solution. In the present invention, the mass ratio of the epoxy solution and the filler is preferably 2-5:1; more preferably 2.5-4.5:1; further preferably 2.8-3.6:1. In the present invention, the temperature of the aging reaction is preferably 45-55°C, more preferably 47-52°C, and further preferably 49-51°C; the time of the aging reaction is preferably not less than 5h, more preferably 5 hours ~20h, more preferably 5~10h.

After the mixed solution is obtained, the mixed solution is supported on the reinforcing material and then dried to obtain the insulating material. In the present invention, the loading preferably includes dipping the reinforcing material in the mixed solution or rolling the mixed solution on the surface of the reinforcing material; the material-to-liquid ratio of the reinforcing material and the mixed solution is preferably 4～ 6:6; more preferably 4-5.5:6; further preferably 4.2-5.2:6; the dipping time is preferably not less than 3min, more preferably 4-6min; the drying is preferably baking; The baking temperature is preferably 172-180°C, more preferably 175-178°C; the baking time is preferably not less than 3 minutes, more preferably 3-4 minutes. In the present invention, after the drying, the obtained insulating material is preferably cut, and the size of the cut is adapted to the size of the material to be treated.

The present invention also provides applications of the insulating material described in the above solution or the insulating material prepared by the preparation method described in the above solution in the field of insulation, fire prevention, moisture and heat resistance and ultra-high voltage. In the present invention, the application method preferably includes: wrapping the insulating material on the surface of the material to be treated, and then pressing and forming; the temperature of pressing and forming is preferably 170-200° C., more preferably 175- 190°C; the compression molding time is preferably 20-50 minutes, more preferably 30-40 minutes; the materials to be treated include any common materials in the field of insulation, fire resistance, heat resistance and ultra-high voltage.

In order to further illustrate the present invention, the solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

FIG. 1 is a process flow of the preparation method and application of the insulating material provided by the present invention. In the present invention, bisphenol A epoxy resin, phenolic epoxy resin and isocyanate modified epoxy resin are first dissolved in MEK to obtain an epoxy solution, and dihydrodiamine and diaminodiphenyl sulfone are dissolved in PMA In the process, a curing agent solution is obtained, and then the obtained epoxy solution and the curing agent solution are mixed and aged, and then tableting is performed, that is, dipping, drying and cutting, and finally pressed into molding.

Example 1

(1) Mix 50 g of bisphenol A epoxy resin, 20 g of phenolic epoxy resin, 10 g of isocyanate modified epoxy resin and 20 g of MEK to obtain an epoxy solution;

(2) dihydrodiamine 2.4g, diaminodiphenyl sulfone 0.4g and PMA 20g are mixed to obtain curing agent solution;

(3) mixing the epoxy solution, the curing agent solution, 15 g of silicon dioxide and 15 g of aluminum hydroxide, and then aging and reacting at 20° C. for 10 hours to obtain a mixed solution;

(4) soak 20 g of 7628 glass fiber in the mixed solution for 6 min, bake at 175° C. for 4 min, and cut to 30 mm×30 mm to obtain an insulating material;

(5) Coating the insulating material on the surface of the material to be treated, and then pressing with the material to be treated at 180° C. for 30 minutes.

Example 2

(1) 52g of bisphenol A epoxy resin, 19g of phenolic epoxy resin, 9g of isocyanate modified epoxy resin and 22g of MEK were mixed to obtain epoxy solution;

(2) 2.3 g of dihydrodiamine, 0.5 g of diaminodiphenyl sulfone and 21 g of PMA are mixed to obtain a curing agent solution;

(3) mixing the epoxy solution, the curing agent solution, 15 g of silicon dioxide and 15 g of aluminum hydroxide, and then aging and reacting at 40° C. for 5 hours to obtain a mixed solution;

(4) soak 22 g of 7628 glass fiber in the mixture for 5 min, bake at 175° C. for 4 min, and cut to 30 mm×30 mm to obtain an insulating material;

(5) Coating the insulating material on the surface of the material to be treated, and then pressing with the material to be treated at 180° C. for 30 minutes.

Example 3

(1) 40g of bisphenol A epoxy resin, 24g of phenolic epoxy resin, 13g of isocyanate modified epoxy resin and 20g of MEK were mixed to obtain epoxy solution;

(2) dihydrodiamine 2.3g, diaminodiphenyl sulfone 0.5g and PMA 23g are mixed to obtain curing agent solution;

(3) mixing the epoxy solution, the curing agent solution, 15 g of silicon dioxide and 15 g of aluminum hydroxide, and then aging and reacting at 30° C. for 8 hours to obtain a mixed solution;

(4) soak 24 g of 7628 glass fiber in the mixed solution for 6 min, bake at 175° C. for 4 min, and cut to 35 mm×30 mm to obtain an insulating material;

(5) Coating the insulating material on the surface of the material to be treated, and then pressing with the material to be treated at 180° C. for 30 minutes.

Example 4

(1) Mix 51 g of bisphenol A epoxy resin, 22 g of phenolic epoxy resin, 14 g of isocyanate modified epoxy resin and 22 g of MEK to obtain an epoxy solution;

(2) dihydrodiamine 2.4g, diaminodiphenyl sulfone 0.3g and PMA 21g are mixed to obtain curing agent solution;

(3) mixing the epoxy solution, the curing agent solution, 15 g of silicon dioxide and 15 g of aluminum hydroxide, and then aging and reacting at 20° C. for 15 hours to obtain a mixed solution;

(4) soak 16g of 7628 glass fiber in the mixture for 4min, bake at 175°C for 4min, and cut to 22mm×30mm to obtain an insulating material;

(5) Coating the insulating material on the surface of the material to be treated, and then pressing with the material to be treated at 180° C. for 30 minutes.

The glass transition temperature T _g of the insulating materials obtained in Examples 1 to 4 was measured by DSC differential scanning calorimeter. The sample was heated from 25°C to 220°C at ramp rate/min, kept at 220°C for 3 minutes, then cooled to 25°C with ramp rate of 10°C/min, kept at 25°C for 3 minutes, and the above operation was repeated once , the _Tg onset and _Tg midpoint were determined from the second heating section, and the results are shown in Table 1.

Table 1 Glass transition temperature of insulating materials of Examples 1 to 4

Test items Example 1 Example 2 Example 3 Example 4 DSC glass transition temperature/℃ 153 152 156 151

It can be seen from Table 1 that the glass transition temperature of the insulating material prepared by the present invention is greater than 150° C., and the glass transition temperature is high, which can meet the performance requirements of insulating materials in the fields of insulation, fire prevention, humidity and heat resistance and ultra-high voltage.

Utilize TGA thermogravimetric analyzer to measure the thermal weight loss temperature (5%) of the insulating materials obtained in Examples 1 to 4, the detection method is: control the nitrogen flow, the balance flow is 40 mL/min, the sample flow is 60 mL/min, and the temperature control program is : The detection temperature is 25 to 400°C, and the heating rate is 10°C/min. The results are shown in Table 2.

Table 2 Thermal weight loss temperature (5%) of insulating materials obtained in Examples 1 to 4

Test items Example 1 Example 2 Example 3 Example 4 TGA thermogravimetric loss temperature (5%)/℃ 312 311 316 313

According to Table 2, the thermal weight loss temperature (5%) of the insulating material prepared by the present invention is greater than 310° C., which shows that the insulating material provided by the present invention has excellent heat resistance.

The flexural strength properties of the insulating materials obtained in Examples 1 to 4 were tested by using a new electronic tensile testing machine. The detection method is: according to the specification of 1mm, the middle width is 6mm, and the length is 115mm. After adjusting to the appropriate fixture and sample height with quick up and quick down, fix it; confirm that the two gauge lengths of the measurement positions in the fixture are 25mm; Press the processing key and the input key in turn, then input the relevant parameters of the sample, save and enter the data processing form, press the report key to run and export the results directly. The results are shown in Table 3.

Table 3 Bending strength of insulating materials obtained in Examples 1 to 4

It can be seen from Table 3 that the flexural strength of the insulating material prepared by the present invention is significantly improved, and the flexural strength is not lower than 307N, which shows that the insulating material provided by the present invention has good toughness.

It can be seen from the above examples that the insulating material provided by the present invention has good toughness, good heat resistance, glass transition temperature greater than 150°C, thermal decomposition temperature (5%) greater than 310°C, cost reduction by more than 30%, and also has dielectric properties. It has strong characteristics and can be used in the field of insulation, fire protection, humidity and heat resistance and ultra-high voltage.

Although the above embodiment has made a detailed description of the present invention, it is only a part of the embodiments of the present invention, rather than all the embodiments, and other embodiments can also be obtained according to the present embodiment without creativity. It belongs to the protection scope of the present invention.

Claims (10)

1. a curable resin system, is characterized in that, comprises component A and component B, described component A is epoxy resin, and described component B is curing agent; Described epoxy resin comprises bisphenol A type epoxy resin, phenolic epoxy resin and isocyanate modified epoxy resin; the curing agent includes one or more of dihydrodiamine and diaminodiphenyl sulfone. 2 . The curable resin system according to claim 1 , wherein the mass ratio of the epoxy resin and the curing agent is 85-95:5-10. 3 . 3. The curable resin system according to claim 1, wherein the content of bisphenol A epoxy resin in the epoxy resin is not less than 40wt%, and the content of phenolic epoxy resin is not less than 20wt% , the content of isocyanate modified epoxy resin is not less than 10wt%. 4. The curable resin system according to claim 1, wherein when the curing agent comprises dihydrodiamine and diaminodiphenyl sulfone, the content of dihydrodiamine in the curing agent is not less than 90wt%, the content of diaminodiphenyl sulfone is not less than 5wt%. 5 . The curable resin system according to claim 1 , wherein the epoxy equivalent of the bisphenol A epoxy resin is 450-500 g/eq, and the epoxy equivalent of the novolac epoxy resin is 200-230 g. 6 . /eq, the epoxy equivalent of isocyanate modified epoxy resin is 270～310g/eq; The active hydrogen equivalent of the dihydrodiamine is 15-25 g/eq, and the active hydrogen equivalent of the diaminodiphenyl sulfone is 60-65 g/eq. 6. curable resin system according to claim 1, is characterized in that, the structural formula of described bisphenol A epoxy resin is:

The structural formula of the novolac epoxy resin is:

The structural formula of the isocyanate-modified epoxy resin is:

Wherein, n ₁ , n ₂ and n ₃ are the degrees of polymerization of epoxy resins, and the value range of n ₁ is preferably 1-20, more preferably 3-15; the value range of n ₂ is preferably 2 ~25, more preferably 7-20; the value range of n ₃ is preferably 1-50, more preferably 10-40, and even more preferably 20-30. 7 . An insulating material, comprising a reinforcing material and an insulating resin layer coated on the surface of the reinforcing material, the insulating resin layer being prepared from the curable resin system and filler according to claims 1 to 6 . 8. The preparation method of the insulating material of claim 7, comprising the following steps: (1) mixing epoxy resin and good solvent to obtain epoxy solution; (2) mixing curing agent and good solvent to obtain curing agent solution; (3) carrying out aging reaction after mixing described epoxy solution, curing agent solution and filler to obtain mixed solution; (4) drying the mixed solution after being loaded on the reinforcing material to obtain an insulating material; The steps (1) and (2) have no time sequence requirement. 9 . The preparation method according to claim 8 , wherein the temperature of the curing reaction is 45-55° C.; the time of the curing reaction is not less than 5 h. 10 . 10. The application of the insulating material according to claim 7 or the insulating material prepared by the preparation method according to any one of claims 8 to 9 in the field of insulation, the field of fire protection, the field of damp heat resistance and the field of ultra-high voltage.

Images