WO2021068304A1 - Phosphorus-containing active ester compound and preparation method therefor - Google Patents

Abstract

Disclosed are a phosphorus-containing active ester compound and a preparation method therefor. The circuit board produced using the phosphorus-containing active ester compound as a curing agent has excellent flame retardancy and low dielectric constant and dielectric loss. Further, the phosphorus-containing active ester compound has a simple preparation process, is easy to implement, and can be used in large-scale production.

Description

Phosphorus-containing active ester compound and preparation method thereof

This application claims the priority of the invention patent application with the application number 201910960552.X filed with the State Intellectual Property Office of China on October 10, 2019. The content of the priority text is expressly incorporated into this application by reference.

Technical field

The present invention relates to the field of materials, in particular, to a phosphorous-containing active ester compound and a preparation method thereof. The circuit substrate prepared by using the phosphorous-containing active ester compound as a curing agent has excellent flame retardancy, and has a dielectric constant and a dielectric constant. The loss is small.

Background technique

In the electronics industry, electronic substrates generally refer to copper clad laminates, which are made of reinforced materials (such as glass cloth) impregnated with resin glue, dried, covered with copper foil, and made by high temperature and high pressure in a hot press . Electronic substrates that use epoxy resin as the adhesive in the glue are currently the most widely used glass fiber cloth type (FR-4, FR-5) substrates. Epoxy resin contains more than two epoxy groups in the molecule. Due to the chemical activity of epoxy groups, it can react with a variety of compounds containing active hydrogen to open the ring, and then cure and crosslink to form a network structure. Commonly used thermosetting resin. Here, the industry usually uses phenolic resin as the curing agent for epoxy resin. Phenolic resin has a high-density heat-resistant benzene ring structure, which makes the cured epoxy resin system excellent in heat resistance.

Nowadays, the information processing speed of electronic products is getting faster and more functions, so the application frequency is getting higher and higher, which has higher requirements for electronic substrates, in addition to maintaining higher heat resistance and resistance. In addition to flammability, the lower the dielectric constant and dielectric loss, the better. However, the existing epoxy glass fiber cloth laminate (FR-4) has gradually been unable to meet the high-frequency and high-speed development application requirements of electronic products. In this regard, the technical staff proposed to modify the phenolic hydroxyl group of the phenolic resin into an active ester as a curing agent for epoxy resin, thereby improving the moisture resistance of the cured product and reducing its water absorption, dielectric constant and dielectric loss value. . However, it is difficult for the cured product to achieve a satisfactory balance between heat resistance and dielectric properties, so as to have a higher glass transition temperature and a lower dielectric loss value at the same time, and make its dielectric properties vary The frequency change remains stable.

Based on the above, in order to improve the performance of epoxy glass fiber cloth laminates, those skilled in the art have made many attempts, such as adding various additives, modifying the molecular structure of epoxy resin and curing agent, etc., in order to obtain The various properties of the substrate, such as heat and humidity resistance, flame retardancy, dielectric constant, dielectric loss value, mechanical properties, etc., have been improved in a balanced manner, but the current effect is not yet satisfactory.

Summary of the invention

[technical problem]

In order to solve the above-mentioned problems, one aspect of the present invention provides a phosphorus-containing active ester compound, a circuit board prepared by using the phosphorus-containing active ester compound as a curing agent has excellent heat resistance and flame retardancy, and has a dielectric constant and The dielectric loss is small.

In addition, another aspect of the present invention also provides a method for preparing the above-mentioned phosphorus-containing active ester compound, which has a simple process, is easy to implement, and can be produced on a large scale.

[Technical solutions]

According to an embodiment of the present invention, there is provided a phosphorus-containing active ester compound, which is represented by the following chemical formula 1:

[Chemical formula 1]

Wherein, X can be any one selected from the following phosphorus-containing groups:

Z or Z'may be the same or different, and are each independently selected from an aryl formyl group containing 1 to 20 carbon atoms or an alkyl formyl group containing 1 to 20 carbon atoms; and

n can be an integer from 1 to 10.

In the present invention, by designing the molecular structure of the curing agent, each functional group and molecular structure can be fully utilized when curing the epoxy resin, and the various physical and electronic properties of the final circuit substrate can be fully improved. Specifically, the phosphorus-containing active ester compound has two active ester groups (namely -OZ and -OZ') in each repeating unit, both of which can play a role in the curing of epoxy resin, which is in the repeating unit. A common phenolic active ester compound containing only one active ester group is twice as effective and can form a wider network structure to improve curing efficiency. In addition, when the active ester group reacts with the epoxy resin, it will not generate a hydroxyl group with greater polarity. In addition, the symmetry of the bisphenol A structure allows the polarities of the phenoloxy groups at both ends to partially offset each other, thus Greatly reduce the dielectric constant and dielectric loss of the final circuit substrate.

In addition, the phosphorous-containing active ester compound according to the present invention also contains a phosphorous-containing group, which has very excellent flame retardant efficacy and very good moisture and heat resistance, and thus can give the final prepared circuit board excellent flame retardant performance and Humidity and heat resistance.

Preferably, in the phosphorus-containing active ester compound according to the present invention, Z or Z'may each independently be an aryl formyl group containing 1 to 12 carbon atoms or an alkyl formyl group containing 1 to 12 carbon atoms, More preferably, it is a benzoyl group, a naphthoyl group, or an alkylformyl group having 1 to 5 carbon atoms.

Preferably, n may be an integer of 1-9, more preferably an integer of 1-7. Within this preferred range, the molecular weight of the phosphorus-containing active ester compound prepared by the present invention is more moderate, and will not prolong the curing time of the epoxy resin due to the too large molecular weight, affecting the curing efficiency, and will not cause too low molecular weight. Curing too fast and affect the crosslinking and setting of epoxy resin.

Within the above range, the phosphorus-containing active ester compound according to the present invention can better exert the performance of curing epoxy resin.

According to another embodiment of the present invention, there is provided a method for preparing the above-mentioned phosphorus-containing active ester compound, which includes the following steps:

(1) Add bisphenol A and chloroform to the alkaline solution, and heat to 60-100°C to react for 2 to 8 hours;

(2) Add the resultant of step (1) and the phosphorus-containing compound K to the acidic solution, and heat to reflux for 2 to 8 hours;

(3) Heating and refluxing the resultant of step (2) and carboxylic acid L or carboxylic acid ester M in the presence of a catalyst for 2 to 10 hours,

Wherein, the phosphorus-containing compound K can be selected from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10-hydrogen -9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxynaphthyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide or 10-(2,5-Dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide,

The carboxylic acid L may be an aryl carboxylic acid containing 1 to 20 carbon atoms or an alkyl carboxylic acid containing 1 to 20 carbon atoms, and

The carboxylic acid ester M may be an aryl carboxylic acid ester containing 1 to 20 carbon atoms or an alkyl carboxylic acid ester containing 1 to 20 carbon atoms.

Through the above preparation method, the phosphorus-containing active ester compound according to the present invention can be prepared under relatively mild reaction conditions, the reaction process is simple, the steps are relatively simple, and the yield is high.

Preferably, in the above step (1), the molar ratio of bisphenol A to chloroform may be 1:1 to 1:3, preferably 1:2. Within this range, the degree of polymerization n of the phosphorus-containing active ester compound prepared by the present invention can be limited to an integer ranging from 1 to 10.

The alkaline solution may be an aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate with a mass concentration of 10%.

The heating temperature in the step (1) may preferably be 70-90°C, and the reaction time may preferably be 4 to 6 hours.

In addition, in step (1), the present invention also includes adding acid to neutralize after the reaction and adding ether to extract the reaction product.

In the present invention, step (1) first carries out the Reimer-Tiemann reaction. In this reaction, the alkaline environment can remove the active hydrogen on the phenolic hydroxyl group of bisphenol A, and then the benzene ring resonates with the oxygen atom to make the benzene ring ortho-position The electron cloud density of chloroform increases, and at the same time, chloroform will form dichlorocarbene in an alkaline environment, which is an electrophilic reagent, will undergo an electrophilic addition reaction with the above-mentioned ortho position, and then hydrolyze to remove the chloride ion to form a product . Here, the para positions of the two benzene rings of bisphenol A are occupied, and only the products of ortho-position addition to aldehyde groups can be produced. Therefore, the reaction selectivity is high and the yield is also high. Afterwards, bisphenol A with ortho-addition of aldehyde groups will continue to undergo phenolic condensation reaction in an alkaline environment to generate linear bisphenol A phenolic resin. That is, the main skeleton of the phosphorus-containing active ester compound of the present invention is generated in one step.

Preferably, in the above step (2), the molar ratio of the resultant from step (1) to the phosphorus-containing compound K may be 0.8:1 to 1.2:1, preferably 1:1

The acidic solution may be an aqueous sulfuric acid solution with a mass concentration of 50% to 70%.

The heating temperature in the step (2) may preferably be 100 to 120° C., and the reaction time may preferably be 4 to 6 hours.

In the present invention, the phosphorus-containing compound K is connected to the aldehyde group of the resultant of step (1) through a nucleophilic reaction. In this reaction, the phosphorus or oxygen element of the phosphorus-containing compound K has an excess electron pair, which will attack the carbon element of the aldehyde group, thereby causing a nucleophilic reaction.

In addition, in step (2), the present invention also includes removing impurities with ethanol after the reaction.

Preferably, in the above step (3), the molar ratio of the resultant from step (2) to the carboxylic acid L or the carboxylic acid ester M may be 1:2 to 1:4, preferably 1:2.

The carboxylic acid L may be at least one selected from benzoic acid, phenylacetic acid, naphthoic acid and naphthaleneacetic acid; and the carboxylic acid ester M may be selected from alkyl benzoate, alkyl phenylacetate, naphthalene At least one of alkyl formate and alkyl naphthaleneacetate is preferably methyl benzoate, methyl phenylacetate, methyl naphthoate, or methyl naphthaleneacetate.

The reaction in the step (3) can use toluene, ethylbenzene or xylene as a solvent, preferably toluene.

The heating temperature in the step (3) may preferably be 105 to 115° C., and the reaction time may preferably be 4 to 6 hours.

In addition, the catalyst in the step (3) may be a Lewis acid catalyst, such as AlCl ₃ , TiCl ₄ or ZnCl ₂ , preferably AlCl ₃ .

In the present invention, the phenolic hydroxyl group of the step (2) will be condensed with the carbonyloxy group of the carboxylic acid L or the carboxylic acid ester M to form a carboxylic acid ester compound of the phenolic hydroxyl group, and the resulting carboxylic acid ester group It is the so-called "active ester", which can undergo condensation reaction with the epoxy group of the epoxy resin at high temperature, thereby playing the role of curing the epoxy resin.

In addition, the present invention also provides a thermosetting resin composition comprising the above-mentioned phosphorus-containing active ester compound as a curing agent.

The present invention also provides a cured product, which is a thermally cured product of the above-mentioned curable resin composition.

The present invention also provides a printed circuit board comprising the above-mentioned cured product.

[Beneficial effect]

The phosphorous-containing active ester compound according to the present invention can be used as a curing agent for the preparation of epoxy resin printed circuit substrates. The flame retardancy of the substrates thus prepared can reach UL94 V0 level, and has good heat resistance and water absorption. Low, as well as small dielectric constant and dielectric loss, can better adapt to various complex electronic environments.

The preparation method of the above-mentioned phosphorus-containing active ester compound according to the present invention is simple in process, easy to realize, and can be produced on a large scale.

Description of the drawings

^{Figure 1 is a 1} HMNR spectrum (1HMNR (300 MHz, DMSO)) of a phosphorus-containing active ester compound prepared according to Example 1 of the present invention.

^{Figure 2 is a 1} HMNR spectrum (1HMNR (300 MHz, DMSO)) of the phosphorus-containing active ester compound prepared according to Example 2 of the present invention.

^{Fig. 3 is a 1} HMNR spectrum (1 HMNR (300 MHz, DMSO)) of the phosphorus-containing active ester compound prepared according to Example 3 of the present invention.

^{Figure 4 is a 1} HMNR spectrum (1HMNR (300 MHz, DMSO)) of the phosphorus-containing active ester compound prepared according to Example 4 of the present invention.

Detailed ways

Hereinafter, preferred embodiments are provided to enable those skilled in the art to better understand the present invention. However, these examples are for illustrative purposes only, and are not intended to limit the present invention to these examples.

Raw material reagent

Bisphenol A: Purity 99.8% or more, from CCP Corporation;

9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide: purity over 99.5%, from Alpha Chemical Company in the United States;

10-(2,5-Dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide: purity over 99.5%, from Alpha Chemical Company, USA;

10-(2,5-Dihydroxynaphthyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide: purity over 99.5%, from Alpha Chemical Company, USA;

10-(2,5-Dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide: purity above 99.5, from Alpha Chemical Company, USA;

Methyl benzoate: purity over 99.0%, from Alpha Chemical Company in the United States;

Epoxy resin: Model XD-1000, from Nippon Kayaku Co., Ltd.

<Example>

Example 1

(1) Add 0.2 mol of bisphenol A and 0.4 mol of chloroform to 150 mL of 10% sodium hydroxide aqueous solution, and heat to 80° C. to react for 5 hours. Afterwards, the reaction system was neutralized with dilute hydrochloric acid to a pH of about 7, and diethyl ether (70 mL×3) was added for extraction, and the organic phase was rotated and dried in a vacuum.

(2) Add 0.1 mol of the result of step (1) and 0.1 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to 50 mL of an aqueous sulfuric acid solution with a mass concentration of 50% , Heating and refluxing at 100°C for 5 hours. After that, the reaction system was washed with ethanol (50 mL×3) to remove impurities and excess sulfuric acid, and the reaction solution was vacuum spin-dried.

(3) Dissolve 0.05 mol of the product of step (2) and 0.1 mol of methyl benzoate in 30 mL of toluene, add 0.02 mol of catalyst AlCl ₃ , and heat and reflux at 110° C. for 6 hours. After that, the reaction system It was washed with saturated brine (10 mL×3), and vacuum-rotated to dry, thereby preparing the phosphorus-containing active ester compound according to the present invention as shown above.

Example 2

In addition to using 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide instead of 9,10-dihydro-9-oxa-10- Phosphaphenanthrene-10-oxide, and the heating temperature of step (2) is other than 120°C, the phosphorus-containing active ester compound according to the present invention as shown above was prepared by the same method as in Example 1.

Example 3

In addition to using 10-(2,5-dihydroxynaphthyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide instead of 9,10-dihydro-9-oxa-10- Phosphaphenanthrene-10-oxide, and the heating temperature of step (2) is other than 120°C, the phosphorus-containing active ester compound according to the present invention as shown above was prepared by the same method as in Example 1.

Example 4

In addition to using 10-(2,5-dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide instead of 9,10-dihydro-9-oxa-10 Phosphaphenanthrene-10-oxide, and the heating temperature of step (2) is not 120°C. The phosphorus-containing active ester compound according to the present invention as shown above was prepared in the same manner as in Example 1.

Comparative Example 1

Commercially available phenolic resin active ester compound (model HPC-8000, from DIC Corporation).

Comparative Example 2

Commercially available phenolic resin active ester compound (model SHC-5100, from Korea Shinya Co., Ltd.).

Test example

Preparation of electronic substrates

The phosphorus-containing active ester compounds prepared in Examples 1 to 4 and the phenolic resin active ester compounds of Comparative Examples 1 to 2 and epoxy resin (model XD-1000) were mixed at an equivalent ratio of 1:1, and 0.3 equivalents were added. A curing accelerator (DMAP) and 0.3 equivalent of filler (aluminum hydroxide) are added, and a solvent (toluene) is added to the mixture to have a solid content of 60%, and the mixture is evenly stirred to obtain a resin composition glue.

After that, the glass cloth was immersed in the resin composition glue, and then the immersed glass was placed in an oven at 140° C. for 8 minutes to form a prepreg. The 8 prepregs were laminated together, and a layer of electrolytic copper foil was laminated on each of the upper and lower sides, and then pressed in a vacuum hot press to obtain a copper-clad laminate. The pressing conditions were: pressure 3.0MPa, pressing at 220°C 2 hour.

Performance Testing

The following test items were used to determine the performance of copper clad laminates prepared using the phosphorus-containing active ester compounds prepared in Examples 1 to 4 and the phenolic resin active ester compounds of Comparative Examples 1 to 2 as curing agents. The results are shown in Table 1 below.

(1) Glass transition temperature (Tg):

Measured according to the DMA (Dynamic Mechanical Analysis) method described in section 2.4.24 of the IPC-TM-650 Test Method Manual, where the heating rate is 5°C/min, the frequency is 10 Hz, and the temperature range is 30-320°C.

(2) Dielectric constant (ε) and dielectric loss tangent (tanδ):

According to the DMA method described in section 2.5.5.9 of the IPC-TM-650 test method manual, the parallel plate method is used to determine the dielectric constant and the dielectric loss tangent at a frequency of 1 GHz. The laminate sample is Before the test, store it for 24 hours in an environment with a temperature of 23°C and a humidity of 50%.

(3) Flame retardancy

Test according to UL94 vertical burning test method.

(4) Immersion tin heat resistance

The test laminate was completely immersed in molten solder at a temperature of 288°C until delamination and blistering appeared on the laminate, and the time for the laminate to appear delamination and blistering was recorded.

(5) Water absorption and tin immersion heat resistance of pressure cooker cooking experiment (PCT)

Put the test laminate into a pressure cooker, add water, cook for 5 hours at 121°C and 105kPa, remove the surface moisture, and calculate the mass percentage added after the laminate is treated, which is the water absorption. After that, the treated laminate was completely immersed in molten solder at a temperature of 288°C until delamination blistering occurred, and the time for the laminate to appear delamination blistering was recorded.

[Table 1]

Referring to Table 1 above, compared to Comparative Examples 1 and 2, the copper clad laminates prepared by using the phosphorus-containing active ester compounds prepared according to Examples 1 to 4 of the present invention as the curing agent have: higher glass transition Temperature, good heat resistance; lower dielectric constant and dielectric loss, indicating excellent dielectric performance, can be more suitable for high-frequency circuit environment; excellent flame retardancy of V0 level; and excellent heat resistance of immersion tin, Low PCT water absorption and excellent PCT immersion tin heat resistance, showing excellent heat and humidity resistance.

Although specific embodiments have been used to illustrate and describe the present invention, those skilled in the art should understand that the technical solutions described in the foregoing embodiments can be modified without departing from the spirit and scope of the present invention. These modifications should also be considered within the scope of the technical solution claimed by the present invention.

Claims (10)

1. A phosphorus-containing active ester compound represented by the following chemical formula 1:

   

   Wherein, X is any one selected from the following phosphorus-containing groups:

   

   Z or Z'are the same or different, and are each independently selected from an aryl formyl group containing 1 to 20 carbon atoms or an alkyl formyl group containing 1 to 20 carbon atoms; and

   n is an integer from 1 to 10.
2. The phosphorus-containing active ester compound according to claim 1, wherein Z or Z'are each independently an aryl formyl group containing 1 to 12 carbon atoms or an alkyl formyl group containing 1 to 12 carbon atoms; and n is an integer from 1 to 9.
3. The phosphorus-containing active ester compound according to claim 2, wherein Z or Z'is each independently a benzoyl group, a naphthoyl group, or an alkylformyl group having 1 to 5 carbon atoms; and n is 1 to 7 Integer.
4. A method for preparing the phosphorus-containing active ester compound according to any one of claims 1 to 3, comprising the following steps:

   (1) Add bisphenol A and chloroform to the alkaline solution, and heat to 60-100°C to react for 2 to 8 hours;

   (2) Add the product obtained in step (1) and the phosphorus-containing compound K to the acidic solution, and heat to reflux for 2 to 8 hours;

   (3) Heating and refluxing the resultant of step (2) and carboxylic acid L or carboxylic acid ester M in the presence of a catalyst for 2 to 10 hours,

   Wherein, the phosphorus-containing compound K is selected from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-10-hydrogen- 9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxynaphthyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide or 10 -(2,5-Dihydroxybiphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide,

   The carboxylic acid L is an aryl carboxylic acid containing 1 to 20 carbon atoms or an alkyl carboxylic acid containing 1 to 20 carbon atoms, and

   The carboxylic acid ester M is an aryl carboxylic acid ester containing 1 to 20 carbon atoms or an alkyl carboxylic acid ester containing 1 to 20 carbon atoms.
5. The preparation method according to claim 4, wherein, in step (1), the molar ratio of bisphenol A to chloroform is 1:1 to 1:3; the alkaline solution is hydrogen with a mass concentration of 10%. An aqueous solution of sodium oxide, potassium hydroxide, sodium carbonate or potassium carbonate; and the heating temperature in the step (1) is 70-90° C., and the reaction time is 4 to 6 hours.
6. The preparation method according to claim 5, wherein in step (1), the molar ratio of bisphenol A to chloroform is 1:2.
7. The preparation method according to claim 4, wherein, in step (2), the molar ratio of the resultant from step (1) to the phosphorus-containing compound K is 0.8:1 to 1.2:1; the acidic solution has a mass concentration of 50 % To 70% sulfuric acid aqueous solution; and the heating temperature in the step (2) is 100 to 120° C., and the reaction time is 4 to 6 hours.
8. The preparation method according to claim 7, wherein, in step (2), the molar ratio of the resultant from step (1) to the phosphorus-containing compound K is 1:1.
9. The preparation method according to claim 4, wherein, in step (3), the molar ratio of the resultant from step (2) to carboxylic acid L or carboxylic acid ester M is 1:2 to 1:4; the carboxylic acid L is at least one selected from benzoic acid, phenylacetic acid, naphthoic acid and naphthoacetic acid, and the carboxylic acid ester M is selected from alkyl benzoate, alkyl phenylacetate, alkyl naphthoate and naphthoacetic acid At least one of the alkyl esters; the reaction in the step (3) uses toluene, ethylbenzene or xylene as the solvent; the heating temperature in the step (3) is 105 to 115° C., and the reaction time is 4 to 6 hours; and the catalyst in step (3) is AlCl ₃ , TiCl ₄ or ZnCl ₂ .
10. The preparation method according to claim 9, wherein, in step (3), the molar ratio of the resultant from step (2) to carboxylic acid L or carboxylic acid ester M is 1:2; the carboxylic acid ester M is benzene Methyl formate, methyl phenylacetate, methyl naphthoate or methyl naphthoacetate; the reaction in the step (3) uses toluene as a solvent; and the catalyst in the step (3) is AlCl ₃ .

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