CN117417518A

CN117417518A - Hyperbranched active ester polymer and preparation method and application thereof

Info

Publication number: CN117417518A
Application number: CN202311534926.4A
Authority: CN
Inventors: 李效玉; 兴安
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2023-11-17
Filing date: 2023-11-17
Publication date: 2024-01-19

Abstract

The invention belongs to the technical field of active ester polymers, and provides a hyperbranched active ester polymer, a preparation method and application thereof. The preparation method comprises the following steps: mixing a phenolic compound, an esterification reagent, a catalyst A and an organic solvent B, then reacting, and adding a reaction solution into a precipitator C to obtain an active ester compound; preparing a hyperbranched active ester polymer by adopting an active ester compound one-step method or two-step method; in the class I hyperbranched active ester polymer, the phenolic compound is a difunctional phenolic compound, and the epoxy resin compound is a polyfunctional epoxy resin compound; in the class II hyperbranched active ester polymer, the phenolic compound is a polyfunctional phenolic compound, and the epoxy resin compound is a difunctional epoxy resin compound. The epoxy resin cured product containing the hyperbranched active ester polymer has lower dielectric constant and lower dielectric loss tangent.

Description

Hyperbranched active ester polymer and preparation method and application thereof

Technical Field

The invention relates to the technical field of active ester polymers, in particular to a hyperbranched active ester polymer and a preparation method and application thereof.

Background

The trend in miniaturization, high integration, and high frequency and high speed signal transmission of electronic devices has placed demands on low dielectric constant and low dielectric loss tangent on insulating dielectric materials. However, the epoxy resin curing system commonly used for printed circuit boards and electronic packages has a problem of a high dielectric constant and a high dielectric loss tangent, and thus it has become an important research topic to reduce the dielectric constant and the dielectric loss tangent of the epoxy resin curing system.

Active hydrogen-containing curing agents (such as organic amine compounds, phenolic compounds, carboxylic acid compounds, thiol compounds and the like) react with epoxy resins to form hydroxyl side groups. On the one hand, according to the Clausius-Mossotti theory, hydroxyl groups increase the dielectric constant of the material due to the high molar polarization of the hydroxyl groups; on the other hand, hydroxyl groups also increase the hygroscopicity of the material. Since the dielectric constant of water is large, moisture absorption increases the dielectric constant of the material. The epoxy resin crosslinked network containing no hydroxyl group is therefore more advantageous in achieving a low dielectric constant and a low dielectric loss tangent. The anhydride curing agent reacts with the epoxy resin under the catalysis of the accelerator to generate no hydroxyl side group, but the anhydride is easy to hydrolyze to generate carboxylic acid, and the carboxylic acid reacts with the epoxy resin to generate the hydroxyl side group. The reactive ester curing agent does not generate hydroxyl side groups when reacting with epoxy resin, and the storage stability of the reactive ester curing agent is better than that of anhydride compounds. Therefore, the active ester curing agent becomes an important raw material for the low dielectric epoxy resin material.

Introducing holes to reduce dipole density is another effective method of reducing the dielectric constant of a material. Hyperbranched polymers having a highly branched structure have a large number of intermolecular/internal free volumes. Therefore, hyperbranched polymer is added into the epoxy resin crosslinking curing system, so that the free volume of the cured product can be increased, the dipole density can be reduced, and the dielectric constant can be further reduced. Meanwhile, a large number of end groups, a highly branched sphere-like shape and a large free volume of the hyperbranched polymer are also advantageous in the aspects of toughening, reinforcing and viscosity reduction of the epoxy resin.

The hyperbranched active ester polymer has the advantages of active ester and hyperbranched polymer, and has good application potential in preparing high-performance low-dielectric epoxy resin materials. Therefore, a hyperbranched active ester polymer with lower dielectric constant and dielectric loss tangent is obtained, and has important value.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a hyperbranched active ester polymer as well as a preparation method and application thereof.

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

the invention provides a hyperbranched active ester polymer, which has the structural formula of

Wherein, in the class I hyperbranched active ester polymer,is a branched structural unit, formed from a polyfunctional epoxy resin compound; />Is a linear structural unit, and is formed by a difunctional active ester compound; r is an organic chain segment and is introduced by an active ester compound;

in the class II hyperbranched active ester polymer,is a branched structural unit, formed from a polyfunctional active ester compound;is a linear structural unit, and is formed by a difunctional epoxy resin compound; r is an organic chain segment and is introduced by an active ester compound.

The invention also provides a preparation method of the hyperbranched active ester polymer, which comprises the following steps:

1) Preparation of active ester compound: mixing a phenolic compound, an esterification reagent, a catalyst A and an organic solvent B, then reacting, and adding a reaction solution into a precipitator C to obtain an active ester compound;

2) A method for preparing hyperbranched active ester polymer: mixing an active ester compound, an epoxy resin compound, a catalyst D and an organic solvent E, and then reacting, wherein the reaction liquid is added into a precipitator F to obtain a hyperbranched active ester polymer;

or preparing hyperbranched active ester polymer by a two-step method: mixing an active ester compound, an epoxy resin compound, a catalyst D and an organic solvent E, and then performing a first reaction to obtain a hyperbranched polymer with a terminal group of an inactive ester group; dropwise adding the inactive ester hyperbranched polymer solution into the active ester compound solution for a second reaction, and adding the reaction solution into the precipitator F to obtain the hyperbranched active ester polymer;

in the class I hyperbranched active ester polymer, the phenolic compound is a difunctional phenolic compound, the active ester compound is a difunctional active ester compound, and the epoxy resin compound is a polyfunctional epoxy resin compound;

in the class II hyperbranched active ester polymer, the phenolic compound is a polyfunctional phenolic compound, the active ester compound is a polyfunctional active ester compound, and the epoxy resin compound is a difunctional epoxy resin compound.

Preferably, the structural formula of the difunctional phenol compound is: HO-X-OH;

wherein, the structural formula of X is:

the structural formula of the polyfunctional phenol compound is as follows:wherein, the structural formula of Y is:

the structural formula of Z is:

preferably, the structural formula of the polyfunctional epoxy resin compound is:

wherein, the structural formula of M is:

the structural formula of U is:

the structural formula of the difunctional epoxy resin compound is as follows:

wherein, the structural formula of T is:

preferably, the esterification reagent in the step 1) is an anhydride compound, an acyl chloride compound or a carboxylic acid compound;

step 1) the catalyst A comprises one or more of sodium acetate, potassium acetate, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, pyridine and triethylamine; step 2) the catalyst D comprises one or more of triethylamine, 2,4, 6-tris (dimethylaminomethyl) phenol, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetraethylammonium bromide, 1-methylimidazole, 2-ethyl-4-methylimidazole and triphenylphosphine.

Preferably, the precipitant C of step 1) comprises one or more of saturated sodium bicarbonate aqueous solution, water, petroleum ether and diethyl ether; the precipitant F in the step 2) comprises one or more of water, ethanol, petroleum ether and diethyl ether.

Preferably, the molar ratio of the phenolic compound, the esterification reagent and the catalyst a in step 1) is 1: 2-20: 0.1 to 0.5;

in the preparation of the hyperbranched active ester polymer by the one-step method in the step 2), the molar ratio of the active ester compound to the epoxy resin compound to the catalyst D is 1:0.1 to 1:0.01 to 0.08;

in the preparation of the hyperbranched active ester polymer by the two-step method in the step 2), the molar ratio of the active ester compound to the epoxy resin compound to the catalyst D is 1:0.5 to 5:0.01 to 0.08.

Preferably, the temperature of the reaction in the step 1) is 5-150 ℃, and the reaction time is 1-24 hours;

in the step 2), the reaction temperature is 80-180 ℃ and the reaction time is 0.5-24 h; in the preparation of the hyperbranched active ester polymer by the two-step method in the step 2), the temperature of the first reaction and the second reaction are independently 80-180 ℃ and the time is independently 0.5-24 h.

The invention also provides application of the hyperbranched active ester polymer in preparing modified epoxy resin cured products.

Preferably, the hyperbranched active ester polymer, the epoxy resin, the curing agent and the accelerator are mixed to obtain a modified epoxy resin cured product;

the mass ratio of the hyperbranched active ester polymer to the epoxy resin is 1-30: 70-100 parts;

the curing agent comprises a phenolic resin curing agent, an amine curing agent, an anhydride curing agent, an organic carboxylic acid curing agent, an active ester curing agent or a cyanate ester curing agent.

The beneficial effects of the invention include:

1) The hyperbranched active ester polymer synthesized by the invention has the structural characteristics of terminal containing a large number of active ester terminal groups, highly branching molecular skeleton, large intermolecular/intramolecular free volume, no hydroxyl side group and strong designability. The active ester end group at the tail end of the polymer can react with epoxy group, so that hyperbranched molecules can be connected into a crosslinked network without causing phase separation; the highly branched structure is beneficial to the dissipation of force and energy, so that the strength and toughness of the material are improved; the large intermolecular/intramolecular free volume is beneficial to the dissipation of energy when the material is stressed, so that the toughness of the material is improved, and the dielectric constant and the dielectric loss tangent of the material are reduced.

2) Unlike phenolic, aminic, carboxylic and thiol compounds, hyperbranched active ester polymers do not generate hydroxyl side groups after reaction with epoxy groups, but generate alkyl ester side groups, thus being beneficial to obtaining materials with low dielectric constants and dielectric loss tangents; hyperbranched active ester polymers with different molecular structures can be obtained by changing the types of the active ester compound and the epoxy resin compound. The hyperbranched active ester polymer has the characteristics of wide sources of preparation raw materials, simple preparation method and strong designability.

3) The invention synthesizes an active ester compound by utilizing the reaction between a phenolic compound and anhydride, acyl chloride or carboxylic acid, and synthesizes a hyperbranched active ester polymer by utilizing the reaction between the active ester compound and an epoxy resin compound. The hyperbranched active ester polymer and the epoxy resin are mixed and used, and a common epoxy resin curing agent is selected for curing to obtain an epoxy resin cured product containing the hyperbranched active ester polymer; the epoxy resin cured product containing the hyperbranched active ester polymer has lower dielectric constant and lower dielectric loss tangent.

Drawings

FIG. 1 is an infrared spectrum of bisphenol A diethyl ester of example 1;

FIG. 2 is an infrared spectrum of the hyperbranched active ester polymer of example 1, the hyperbranched polymer of example 16 in which the end groups of the first step are inactive ester groups, and the hyperbranched active ester polymer of the second step, wherein HBPAE-1 is example 1, HBPEP is the hyperbranched polymer of example 16 in which the end groups are inactive ester groups, and HBPAE-2 is the hyperbranched active ester polymer of example 16;

FIG. 3 is a nuclear magnetic resonance hydrogen spectrum of bisphenol A diethyl ester of example 1;

FIG. 4 is a nuclear magnetic resonance spectrum of the hyperbranched active ester polymer of example 1;

FIG. 5 is a nuclear magnetic resonance spectrum of a hyperbranched polymer having an inactive ester group as a terminal group in the first step of example 16;

FIG. 6 is a nuclear magnetic resonance spectrum of the hyperbranched active ester polymer of the second step of example 16;

FIG. 7 is a thermal weight loss curve of the hyperbranched active ester polymer of example 1, the hyperbranched polymer of example 16 wherein the end groups of the first step are inactive ester groups, and the hyperbranched active ester polymer of example 16 wherein HBPAE-1 is example 1, HBPEP is the hyperbranched polymer of example 16 wherein the end groups are inactive ester groups, and HBPAE-2 is the hyperbranched active ester polymer of example 16;

FIG. 8 is a DSC secondary temperature rise scan curve of the hyperbranched active ester polymer modified epoxy resin cure of examples 25-28 and the unmodified pure bisphenol A epoxy resin cure of comparative example 1;

FIG. 9 is a graph of dielectric constants as a function of frequency for hyperbranched active ester polymer modified epoxy resin cured products of examples 25-28 and unmodified pure bisphenol A type epoxy resin cured product of comparative example 1;

FIG. 10 is a graph showing the change in dielectric loss tangent with frequency of the hyperbranched active ester polymer-modified epoxy resin cured product of examples 25 to 28 and the unmodified pure bisphenol A type epoxy resin cured product of comparative example 1.

Detailed Description

In the present invention, the structural formula of the difunctional phenol compound is preferably: HO-X-OH;

wherein, the structural formula of X is preferably:

the structural formula of the polyfunctional phenol compound is preferably:

wherein, the structural formula of Y is preferably:

the structural formula of Z is preferably:

in the present invention, the structural formula of the polyfunctional epoxy resin compound is preferably:

/>

wherein, the structural formula of M is preferably:

the structural formula of U is preferably:

the structural formula of the difunctional epoxy resin compound is preferably:

wherein, the structural formula of T is preferably:

in the invention, the esterification reagent in the step 1) is preferably an anhydride compound, an acyl chloride compound or a carboxylic acid compound; further preferred is one or more of acetic anhydride, benzoic anhydride, methacrylic anhydride, acetyl chloride, benzoyl chloride and acetic acid.

In the present invention, the catalyst a of step 1) preferably comprises one or more of sodium acetate, potassium acetate, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, pyridine and triethylamine; catalyst D of step 2) preferably comprises one or more of triethylamine, 2,4, 6-tris (dimethylaminomethyl) phenol, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetraethylammonium bromide, 1-methylimidazole, 2-ethyl-4-methylimidazole and triphenylphosphine.

In the present invention, the organic solvent B of step 1) preferably contains one or more of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, methylene chloride, toluene, dichloroethane, chloroform, methyl isobutyl ketone, tetrahydrofuran and dioxane.

In the present invention, the precipitant C of step 1) preferably comprises one or more of saturated sodium bicarbonate aqueous solution, water, petroleum ether and diethyl ether; the precipitant F of step 2) preferably comprises one or more of water, ethanol, petroleum ether and diethyl ether.

In the present invention, the solvent in the inactive ester group hyperbranched polymer solution and the active ester compound solution in step 2) is preferably an organic solvent E, and the organic solvent E preferably contains one or more of N, N-dimethylformamide, N-dimethylacetamide, cyclohexanone, dimethylsulfoxide, and N-methylpyrrolidone.

In the present invention, the molar ratio of the phenolic compound, the esterification reagent and the catalyst a in step 1) is preferably 1: 2-20: 0.1 to 0.5, more preferably 1:5 to 16:0.2 to 0.4, more preferably 1: 8-12: 0.25 to 0.35.

In the present invention, the molar volume ratio of the phenolic compound and the organic solvent B in step 1) is preferably 1mmol:3 to 15mL, more preferably 1mmol:5 to 12mL, more preferably 1mmol: 8-10 mL.

In the preparation of the hyperbranched active ester polymer by the one-step method in the step 2), the molar ratio of the active ester compound to the epoxy resin compound to the catalyst D is preferably 1:0.1 to 1:0.01 to 0.08, more preferably 1:0.2 to 0.8:0.02 to 0.07, more preferably 1:0.4 to 0.6:0.03 to 0.05;

in the preparation of hyperbranched active ester polymers by the two-step process described in step 2), the molar ratio of active ester compound, epoxy resin compound and catalyst D is preferably 1:0.5 to 5:0.01 to 0.08, more preferably 1:0.8 to 4.5:0.02 to 0.07, more preferably 1:1.5 to 4:0.03 to 0.06.

In the preparation of the hyperbranched active ester polymer by the one-step method in the step 2), the molar volume ratio of the active ester compound to the organic solvent E is preferably 1mmol:1 to 8mL, more preferably 1mmol:2 to 7mL, more preferably 1mmol: 3-6 mL;

in the preparation of hyperbranched active ester polymers by the two-stage process described in step 2), the molar volume ratio of active ester compound to organic solvent E is preferably 1mmol:0.5 to 5mL, more preferably 1mmol:0.8 to 4mL, more preferably 1mmol: 1.5-3 mL.

In the steps 1) and 2) of the invention, the volume ratio of the organic solvent to the precipitant is independently preferably 1:5 to 8, more preferably 1:6 to 7.

In the present invention, the temperature of the reaction in step 1) is preferably 5 to 150 ℃, more preferably 50 to 140 ℃, and even more preferably 110 to 130 ℃; the reaction time is preferably 1 to 24 hours, more preferably 6 to 20 hours, still more preferably 10 to 12 hours;

in the preparation of the hyperbranched active ester polymer by the one-step method in the step 2), the reaction temperature is preferably 80-180 ℃, more preferably 100-160 ℃, and even more preferably 130-140 ℃; the reaction time is preferably 0.5 to 24 hours, more preferably 2 to 20 hours, still more preferably 6 to 15 hours; in the preparation of the hyperbranched active ester polymer by the two-step method in the step 2), the temperature of the first reaction and the second reaction is independently preferably 80-180 ℃, further preferably 100-160 ℃, and more preferably 130-140 ℃; the time independent is preferably 0.5 to 24 hours, more preferably 2 to 20 hours, still more preferably 6 to 15 hours.

In the invention, hyperbranched active ester polymer, epoxy resin, curing agent and accelerator are mixed to obtain modified epoxy resin cured product;

the mass ratio of the hyperbranched active ester polymer to the epoxy resin is preferably 1-30: 70 to 100, more preferably 3 to 25:75 to 95, more preferably 8 to 20: 80-90;

the curing agent preferably comprises a phenolic resin curing agent, an amine curing agent, an anhydride curing agent, an organic carboxylic acid curing agent, an activated ester curing agent, or a cyanate ester curing agent.

In the present invention, the temperature of the mixing is preferably 50 to 200 ℃, more preferably 80 to 160 ℃, and still more preferably 100 to 150 ℃.

In the invention, after uniformly mixing and completely dissolving the curing agent, vacuum defoamation, injection into a mold and curing molding are sequentially carried out to obtain a modified epoxy resin cured product; the temperature of the vacuum degassing is preferably 50 to 200 ℃, more preferably 80 to 160 ℃, and even more preferably 100 to 150 ℃; the time for vacuum deaeration is preferably 1 to 15 minutes, more preferably 3 to 12 minutes, and still more preferably 5 to 10 minutes; the vacuum degree of the vacuum defoamation is preferably less than or equal to 133Pa, and more preferably less than or equal to 120Pa; the curing and molding temperature is preferably 25 to 250 ℃, more preferably 50 to 200 ℃, and even more preferably 80 to 150 ℃; the curing time is preferably 0.5 to 24 hours, more preferably 1 to 20 hours, and still more preferably 5 to 15 hours.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

8.13g (35.6 mmol) of bisphenol A and 0.50g (6.1 mmol) of sodium acetate were charged into a reactor containing 250mLN, N-dimethylacetamide, and after completion of the dissolution, 51.1g (500 mmol) of acetic anhydride was added dropwise, and after completion of the dropwise addition, the reaction was stirred at 130℃for 12 hours. After the completion of the reaction, the reaction solution was poured into 1500mL of a saturated aqueous sodium hydrogencarbonate solution to precipitate a crude product, which was dissolved with tetrahydrofuran and then precipitated in the saturated aqueous sodium hydrogencarbonate solution. Tetrahydrofuran dissolution and precipitation in saturated aqueous sodium bicarbonate solution were repeated three times. And drying the precipitate to obtain bisphenol A diethyl ester.

1.32g (4.4 mmol) of triglycidyl isocyanurate and 3.12g (10 mmol) of bisphenol A diethyl ester were added to a reactor containing 35mLN, N-dimethylformamide. After stirring at 110℃until the material is completely dissolved 0.0782g (0.64 mmol) of the catalyst 4-dimethylaminopyridine are added. The reaction was carried out at 140℃for 2h. After the reaction was completed, the reaction solution was poured into 210mL of water to precipitate a crude product, which was dissolved in tetrahydrofuran, and then precipitated again in water. The tetrahydrofuran dissolution product was then precipitated in 210mL of absolute ethanol, and tetrahydrofuran dissolution and precipitation in absolute ethanol were each performed twice. And drying the precipitate to obtain the hyperbranched active ester polymer with the end group being an active ester group.

Example 2

The procedure of example 1 was repeated except that the acetic anhydride of example 1 was replaced with acetic anhydride of 72.7 g.

Example 3

0.50g of sodium acetate of example 1 was replaced with 0.87g of sodium acetate, and the other conditions were the same as in example 1.

Example 4

The reaction temperature 130℃for preparing bisphenol A diethyl ester of example 1 was replaced by 110℃and the other conditions were the same as those of example 1.

Example 5

The reaction time for preparing bisphenol A diethyl ester of example 1 was replaced with 6h, and the other conditions were the same as in example 1.

Example 6

8.13g of bisphenol A of example 1 was replaced with 11.97g of bisphenol AF and 3.12g of bisphenol A diethyl ester was replaced with 4.20g of bisphenol AF diethyl ester, under the same conditions as in example 1.

Example 7

250mLN, N-dimethylacetamide from example 1 was replaced with 250mL dimethylsulfoxide, and the other conditions were the same as in example 1.

Example 8

The temperature 140℃for preparing the hyperbranched active ester polymer of example 1 was replaced by 130℃and the other conditions were the same as in example 1.

Example 9

The time 2h for preparing the hyperbranched active ester polymer of example 1 was replaced by 6h, the other conditions being the same as in example 1.

Example 10

1.32g of triglycidyl isocyanurate of example 1 was replaced with 1.49g of triglycidyl isocyanurate, and the same conditions as in example 1 were used.

Example 11

0.0782g of catalyst 4-dimethylaminopyridine from example 1 was replaced with 0.0391g of catalyst 4-dimethylaminopyridine, with the same exception as in example 1.

Example 12

1.32g of triglycidyl isocyanurate of example 1 was replaced by 2.03g of triglycidyl methane triglycidyl ether, with the same conditions as in example 1.

Example 13

0.0782g of the catalyst 4-dimethylaminopyridine of example 1 was replaced by 0.1934g of the catalyst tetrabutylammonium bromide, with the same conditions as in example 1.

Example 14

0.0782g of the catalyst 4-dimethylaminopyridine of example 1 was replaced by 0.0492g of the catalyst 2-methylimidazole, the other conditions being the same as in example 1.

Example 15

35mLN, N-dimethylformamide in example 1 was replaced with 35mL of dimethyl sulfoxide, and the conditions were the same as in example 1.

Example 16

The process conditions for preparing bisphenol A diethyl ester were the same as in example 1, which uses a two-step process to prepare hyperbranched active ester polymers.

The first step: 2.99g (10 mmol) of triglycidyl isocyanurate and 3.12g (10 mmol) of bisphenol A diethyl ester were added to a reactor containing 35mLN, N-dimethylformamide. After stirring at 110℃until the material is completely dissolved, 0.044g (0.36 mmol) of the catalyst 4-dimethylaminopyridine is added. And (3) reacting for 2 hours at 140 ℃ to obtain the hyperbranched polymer solution with the end group being an inactive ester group.

And a second step of: 3.12g (10 mmol) of bisphenol A diethyl ester were charged to a reactor containing 15mLN, N-dimethylformamide. The hyperbranched polymer solution with the end groups of the inactive ester groups was slowly added dropwise to the bisphenol A diethyl ester solution at a rate of one drop per two seconds under stirring at 220rpm in an environment of 140℃and reacted for 2 hours. After the reaction, the reaction mixture was poured into 90mL of water to precipitate a crude product, which was dissolved in tetrahydrofuran, and then precipitated again in water. The product was dissolved with tetrahydrofuran and then precipitated in 90mL of absolute ethanol. Tetrahydrofuran dissolution and precipitation in absolute ethanol were each performed twice. And drying the precipitate to obtain the hyperbranched active ester polymer with the end group being an active ester group.

Example 17

The temperature 140℃for preparing the hyperbranched active ester polymer of example 16 was replaced by 130℃and the other conditions were the same as in example 16.

Example 18

The reaction time 2h in both the first and second steps of example 16 was replaced with 6h, and the other conditions were the same as in example 16.

Example 19

2.99g of triglycidyl isocyanurate in the first step of example 16 was replaced with 3.86g of triglycidyl isocyanurate, with the same other conditions as in example 16.

Example 20

The procedure of example 1 was repeated except that 0.044g of catalyst 4-dimethylaminopyridine in the first step of example 16 was replaced with 0.061g of catalyst 4-dimethylaminopyridine.

Example 21

2.99g of triglycidyl isocyanurate of example 16 was replaced with 4.60g of triglycidyl methane triglycidyl ether, with the same conditions as in example 1.

Example 22

0.044g of 4-dimethylaminopyridine catalyst from example 16 was replaced with 0.116g of tetrabutylammonium bromide catalyst, and the conditions were the same as in example 1.

Example 23

0.044g of catalyst 4-dimethylaminopyridine of example 16 was replaced with 0.030g of catalyst 2-methylimidazole, the other conditions being the same as in example 16.

Example 24

35mLN, N-dimethylformamide in the first step and 15mLN, N-dimethylformamide in the second step of example 16 were replaced with 35mL of dimethyl sulfoxide and 15mL of dimethyl sulfoxide, respectively, and the other conditions were the same as in example 16.

The infrared spectrum of bisphenol A diethyl ester of example 1 is shown in FIG. 1.

The infrared spectra of the hyperbranched active ester polymer of example 1, the hyperbranched polymer of example 16 in which the end groups of the first step are inactive ester groups and the hyperbranched active ester polymer of the second step are shown in FIG. 2, wherein HBPAE-1 is example 1, HBPEP is the hyperbranched polymer of example 16 in which the end groups are inactive ester groups, and HBPAE-2 is the hyperbranched active ester polymer of example 16.

The nuclear magnetic resonance spectrum of bisphenol A diethyl ester of example 1 is shown in FIG. 3; the nuclear magnetic resonance spectrum of the hyperbranched active ester polymer of example 1 is shown in fig. 4; example 16 Nuclear magnetic resonance spectrum of hyperbranched polymer with end groups of inactive ester groups in the first step is shown in figure 5; the nuclear magnetic resonance spectrum of the hyperbranched active ester polymer in the second step of example 16 is shown in FIG. 6.

The thermal weight loss curves of the hyperbranched active ester polymer of example 1, the hyperbranched polymer of example 16 in which the end groups of the first step are inactive ester groups, and the hyperbranched active ester polymer of example 16 in the second step are shown in FIG. 7, wherein HBPAE-1 is example 1, HBPEP is the hyperbranched polymer of example 16 in which the end groups are inactive ester groups, and HBPAE-2 is the hyperbranched active ester polymer of example 16. As can be seen from FIG. 7, T of three hyperbranched polymers _d5％ All are higher than 270 ℃, which shows that the thermal decomposition stability is better; second, T of the terminal active ester hyperbranched polymers HBPAE1 and HBPAE2 _dmax Is higher than non-terminal active ester hyperbranched polymer HBPEP.

Example 25

0.5g of hyperbranched active ester polymer is added into 10g of bisphenol A epoxy resin (Taiwan Chiu 188 epoxy resin, epoxy value is 0.53mol/100 g), and holy spring PF8711 phenolic resin curing agent is added, wherein the mole number of epoxy groups in the curing system is equal to the sum of the mole number of active ester groups and the mole number of phenolic hydroxyl groups. Then adding an accelerator 2-methylimidazole and butanone/cyclohexanone mixed solvent (the volume ratio of butanone to cyclohexanone is 2:8) accounting for 0.94 percent of the mass of the bisphenol A epoxy resin, and uniformly mixing the mixture at 100 ℃ to ensure that the reaction system is completely dissolved, wherein the solid content of the curing system is 70 percent. Vacuum defoamation is carried out on the reaction system for 8min at 150 ℃ and 130Pa, then the reaction system is poured into a silica gel mold, and after solvent volatilization, the reaction system is sequentially cured for 3h at 50 ℃, 5h at 100 ℃, 2h at 150 ℃ and 5h at 220 ℃ to obtain a modified epoxy resin cured product.

Example 26

0.5g of the hyperbranched active ester polymer of example 25 was replaced with 1.0g of the hyperbranched active ester polymer, and the other conditions were the same as in example 25.

Example 27

0.5g of the hyperbranched active ester polymer of example 25 was replaced with 1.5g of the hyperbranched active ester polymer, and the other conditions were the same as in example 25.

Example 28

0.5g of the hyperbranched active ester polymer of example 25 was replaced with 2.0g of the hyperbranched active ester polymer, and the other conditions were the same as in example 25.

Example 29

10g of bisphenol A type epoxy resin of example 25 was replaced with 10g of cyclopentadienyl phenol epoxy resin, and the conditions were the same as in example 25.

Example 30

The phenolic resin curing agent of the holy spring PF8711 of example 25 was replaced with an amine curing agent triethylenetetramine, and the number of moles of epoxy groups in the curing system was equal to the sum of the number of moles of active ester groups and the number of moles of active hydrogens on the amino group. Other conditions were the same as in example 25.

Example 31

The holy spring PF8711 phenolic resin curative of example 25 was replaced with the anhydride curative methyl nadic anhydride, with the number of moles of epoxy groups in the curing system equal to the sum of the moles of active ester groups and the moles of anhydride groups. Other conditions were the same as in example 25.

Example 32

The holy spring PF8711 phenolic resin curing agent of example 25 was replaced with an organic carboxylic acid curing agent trimellitic acid, where the number of moles of epoxy groups in the curing system was equal to the sum of the moles of active ester groups and the moles of carboxyl groups. Other conditions were the same as in example 25.

Example 33

The phenolic resin curing agent of holy spring PF8711 of example 25 was replaced with an active ester curing agent, east 618, with the number of moles of epoxy groups in the curing system equal to the number of moles of active ester groups. Other conditions were the same as in example 25.

Example 34

The holy spring PF8711 phenolic resin curative of example 25 was replaced with the cyanate curative, tianqi bisphenol A cyanate C01MO. Other conditions were the same as in example 25.

Example 35

The accelerator 2-methylimidazole of example 25 was replaced with 2,4, 6-tris (dimethylaminomethyl) phenol. Other conditions were the same as in example 25.

Comparative example 1

0.5g of hyperbranched active ester polymer from example 25 was omitted, the other conditions being the same as in example 25.

The DSC secondary temperature rise scan curves of the hyperbranched active ester polymer-modified epoxy resin cured products of examples 25 to 28 and the unmodified pure bisphenol A type epoxy resin cured product of comparative example 1 are shown in FIG. 8.

The dielectric constants of the hyperbranched active ester polymer-modified epoxy resin cured products of examples 25 to 28 and the unmodified pure bisphenol A type epoxy resin cured product of comparative example 1 are plotted as a function of frequency, as shown in FIG. 9.

The dielectric loss tangent versus frequency graphs of the hyperbranched active ester polymer modified epoxy resin cured products of examples 25-28 and the unmodified pure bisphenol A type epoxy resin cured product of comparative example 1 are shown in FIG. 10.

In FIGS. 8-10, 0wt% HBPAE-1 or DGEBA/PF8711 was comparative example 1, 5wt% HBPAE-1 was example 25, 10wt% HBPAE-1 was example 26, 15wt% HBPAE-1 was example 27, and 20wt% HBPAE-1 was example 28. As is clear from FIG. 8, when the amount of HBPAE-1 added was increased from 0wt% to 10wt%, T of the cured product was obtained _g As the addition amount of HBPAE-1 is increased and reduced, alkyl ester side group is generated after the reaction of active ester group and epoxy group, hydroxyl side group is generated after the reaction of phenolic hydroxyl group and epoxy group, and hydroxyl with high polarity can increase the action between chain segments through the action of hydrogen bond and the like, so that the crosslinked network has higher T _g Using low polarityAlkyl ester groups substituted for hydroxyl groups reduce the inter-chain segment action and lower T of the cured product _g . At the same time, as a more bulky flexible suspension chain, alkyl ester groups can make the inter-segment distance larger, loosening the network, which can also cause T _g Is reduced. However, when the amount of HBPAE-1 added was further increased from 10 to 20wt%, T of the cured product was increased _g Without decreasing the reaction and increasing the quantity. This is due to the fact that a large number of reactive end groups of the hyperbranched active esters are connected into the cross-linked network, and the effect of increasing the cross-linked density caused by the hyperbranched structure is greater than the plasticizing effect of the alkyl ester side groups. The variation in crosslink density due to hyperbranched structure and plasticization of alkyl ester side groups synergistically determine the cured product T _g And the addition amount of the hyperbranched active ester changes. As can be seen from fig. 9 and 10, when HBPAE-1 is added in an amount ranging from 0 to 20wt%, the modified cured system exhibits lower dielectric constant and dielectric loss tangent than the unmodified system. With increasing amounts of HBPAE-1 added, both the dielectric constant and the dielectric loss tangent show a tendency to decrease and then increase. When the amount of HBPAE-1 added was 15wt%, the dielectric constant and dielectric loss tangent (at 1 MHz) were the lowest, 4.25 and 0.0139.

The solubility of the hyperbranched active ester polymer of example 1 is shown in Table 1, the solubility of the hyperbranched polymer having the end groups of the first step of example 16 being inactive ester groups is shown in Table 2, and the solubility of the hyperbranched active ester polymer of the second step of example 16 is shown in Table 3.

Table 1 solubility of hyperbranched active ester polymers of example 1

Wherein, -represents insoluble, + represents room temperature dissolution, ±represents heated dissolution.

TABLE 2 solubility of hyperbranched polymers with end groups of the first step of example 16 being inactive ester groups

TABLE 3 solubility of hyperbranched active ester polymers from example 16 second step

The hyperbranched active ester polymer-modified epoxy resin cured product of examples 25 to 28 and the unmodified pure bisphenol A-type epoxy resin cured product of comparative example 1 have dielectric constants, dielectric loss tangents and T _g The test results are shown in Table 4.

Table 4 results of Performance test of the epoxy resin cured products of examples 25 to 28 and comparative example 1

/>

As is clear from Table 4, the hyperbranched active ester polymer of the present invention can reduce the dielectric constant and dielectric loss tangent of the cured epoxy resin. When the mass of the hyperbranched active ester polymer was 15% of the mass of the bisphenol A type epoxy resin (example 27), the dielectric constant of the cured epoxy resin modified with the hyperbranched active ester polymer was 4.25 at 1MHz, and the dielectric loss tangent at 1MHz was 1.39X10 ^-2 The unmodified pure bisphenol a epoxy resin cured product of comparative example 1 was reduced by 9.8% and 10.3%, respectively.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims

1. A hyperbranched active ester polymer is characterized in that the structural formula of the hyperbranched active ester polymer is

in the class II hyperbranched active ester polymer,is a branched structural unit, formed from a polyfunctional active ester compound; />Is a linear structural unit, and is formed by a difunctional epoxy resin compound; r is an organic chain segment and is introduced by an active ester compound.

2. The method of preparing a hyperbranched active ester polymer according to claim 1, comprising the steps of:

3. The method of claim 2, wherein the difunctional phenolic compound has the structural formula: HO-X-OH;

wherein, the structural formula of X is:

the structural formula of Z is:

4. the method of claim 2, wherein the polyfunctional epoxy resin compound has the structural formula:

wherein, the structural formula of M is:

the structural formula of U is:

the structural formula of the difunctional epoxy resin compound is as follows:

wherein, the structural formula of T is:

5. the method according to claim 3 or 4, wherein the esterifying reagent in step 1) is an acid anhydride compound, an acid chloride compound or a carboxylic acid compound;

6. The preparation method according to claim 5, wherein the precipitant C in step 1) comprises one or more of saturated sodium bicarbonate aqueous solution, water, petroleum ether and diethyl ether; the precipitant F in the step 2) comprises one or more of water, ethanol, petroleum ether and diethyl ether.

7. The method according to claim 2 or 6, wherein the molar ratio of the phenolic compound, the esterification reagent and the catalyst a in step 1) is 1: 2-20: 0.1 to 0.5;

8. The preparation method according to claim 7, wherein the reaction temperature in step 1) is 5-150 ℃ and the reaction time is 1-24 hours;

9. The use of the hyperbranched active ester polymer according to claim 1 for producing a modified epoxy resin cured product.

10. The use according to claim 9, characterized in that the hyperbranched active ester polymer, the epoxy resin, the curing agent and the accelerator are mixed to obtain a modified epoxy resin cured product;