CN112426752A - Non-silicon defoaming agent for printed circuit board developing solution and preparation method thereof - Google Patents

Abstract

The invention discloses a non-silicon defoaming agent for a developing solution of a printed circuit board, which comprises the following components in parts by weight: 250 portions of tributyl phosphate, 200 portions of ethylene glycol, 200 portions of propylene glycol block polyether, 20 to 50 portions of thickening agent, 5 to 15 portions of emulsifying agent, 5 to 15 portions of glycerin monostearate and 70 to 520 portions of pure water. The defoaming agent has excellent defoaming and foam inhibiting capabilities, is not easy to remain, and meets the requirements of the PCB developing process.

Description

Non-silicon defoaming agent for printed circuit board developing solution and preparation method thereof

Technical Field

The invention relates to the technical field of defoaming agents, in particular to a non-silicon defoaming agent for a developing solution of a printed circuit board and a preparation method thereof.

Background

Defoamers are chemical additives that reduce the surface tension of water, solutions, suspensions, etc., preventing foam formation or reducing and destroying the original foam. The application of the defoaming agent in the industrial field is very wide, and the defoaming agent is almost used for inhibiting harmful foams generated in the process from food production to daily chemical washing, from petroleum mining to printing and dyeing coating, and from medical synthesis to electronic manufacturing.

In a process for manufacturing a Circuit pattern of a Printed Circuit Board (PCB), a photoresist layer in the form of a dry film or a wet film is required to be attached or coated on a conductive layer, and after the photoresist is selectively exposed to active radiation such as ultraviolet rays, X-rays, and electron rays, the resist which undergoes a curing reaction temporarily remains on the Board surface to protect the conductive layer, while the resist which does not undergo an exposure and curing reaction is removed by a developing process. The development process of PCBs generally employs an alkaline developer prepared from alkali metal carbonate, alkali metal hydroxide, tetramethylammonium hydroxide, and the like. For a resist in which a photo-curing reaction does not occur, components such as a resin, a dye, a pigment, a polymerization initiator, and a crosslinking agent contained therein are dissolved and dispersed in a developing solution. Because the developing process generally adopts a spraying circulating working mode, air can continuously enter the developing working solution to generate foam, and the foam can be continuously accumulated along with the continuous melting of the components of the corrosion inhibitor, so that the developing quality can be influenced to a certain degree, and the production is inconvenient. Therefore, in the development process of PCB production, it is necessary to add a defoaming agent to the developing solution to suppress the generation of foam and reduce or eliminate the foam generated during the development process. According to the quality management standard of the PCB manufacturing process, the PCB developing process has strict requirements on defoaming agents, has excellent defoaming and foam inhibiting capabilities, cannot have any residue on a printed board, and is effective under an alkaline condition.

The traditional emulsified silicone oil defoaming is forbidden because the traditional emulsified silicone oil defoaming is easy to demulsify and float oil in the diluting process and can pollute the board surface of a PCB. However, the industrial non-silicon defoaming agent still has a difference from the silicon-containing defoaming agent in instantaneous defoaming capability, and equipment for preparing the non-silicon defoaming agent is complex in structure and complex in process, and higher equipment and labor cost are required to be invested. A polyether-based non-silicon defoaming agent such as that disclosed in patent CN11508037A requires a plurality of mixing barrels, heating water tanks and semiconductor refrigerators, and also employs a PLC controller, which increases the production cost of the defoaming agent. The preparation method of the amide defoaming agent disclosed in patent CN110283092A also shows that the preparation process is complicated, and dehydration condensation reaction, vacuum distillation and solid-liquid separation steps are required. The patent CN110152357A discloses a defoaming agent for extracting phosphoric acid production, which has the advantages of simple process and easy preparation, but the component of the defoaming agent is not suitable for PCB alkaline developer.

Therefore, a defoaming agent which has excellent defoaming and foam inhibiting capabilities, simple preparation method and compatibility with an alkaline developing solution is needed in the PCB manufacturing industry so as to meet the requirements of the developing process.

Disclosure of Invention

In order to solve the problems in the background art, the invention aims to provide a non-silicon defoamer for a developing solution of a printed circuit board, which has excellent defoaming and foam inhibiting capabilities, is not easy to remain and meets the requirements of a PCB developing process. In addition, the invention also provides a preparation method of the non-silicon defoaming agent for the developing solution of the printed circuit board.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a non-silicon defoaming agent for a developing solution of a printed circuit board, which comprises the following components in parts by weight: 250 portions of tributyl phosphate, 200 portions of ethylene glycol, 200 portions of propylene glycol block polyether, 20 to 50 portions of thickening agent, 5 to 15 portions of emulsifying agent, 5 to 15 portions of glycerin monostearate and 70 to 520 portions of pure water.

Preferably, the propylene glycol block polyether is a block polymer synthesized by addition polymerization of propylene glycol as an initiator and an epoxide under the action of a catalyst.

Preferably, the epoxide is one or two of polyoxyethylene and polypropylene ethylene.

Preferably, the molecular weight of the propylene glycol block polyether is 2000-3000. Specifically, the propylene glycol block polyether can be selected from polyether L61, polyether L62, polyether L63 or polyether L64.

Preferably, the thickener is any one of soluble starch, gum arabic, sodium polyacrylate and polyvinylpyrrolidone.

Preferably, the emulsifier is tween 60 (chemical name polyoxyethylene sorbitan stearate) or span 60 (chemical name sorbitan monostearate).

In a second aspect of the present invention, a method for preparing the non-silicon defoamer for a printed circuit board developer is provided, which comprises the following steps:

s1, weighing tributyl phosphate and ethylene glycol according to the weight ratio, adding the tributyl phosphate and the ethylene glycol into the reaction vessel, and continuously stirring until the mixed solution in the reaction vessel is clear and has no layering;

s2, adding propylene glycol block polyether and a thickening agent into the reaction vessel, and continuously stirring until the mixed solution in the reaction vessel is clear and has no layering;

s3, continuously adding the emulsifier and the glyceryl monostearate into the reaction vessel, heating to 75-85 ℃ under the stirring condition to completely dissolve the emulsifier, wherein the mixed solution in the reaction vessel is clear and has no layering;

s4, slowly adding 1/3 volume percent of pure water at the temperature of 75-85 ℃ into the reaction container, and continuously stirring to obtain a water-in-oil type transparent paste;

s5, adding the residual 2/3 pure water with the temperature of 75-85 ℃ into the reaction vessel, naturally cooling to 60 ℃ under the stirring condition, converting the water-in-oil type transparent paste in the reaction vessel into oil-in-water type emulsion, and cooling to room temperature to obtain the non-silicon defoaming agent.

Compared with the prior art, the invention has the following beneficial effects:

the defoaming agent provided by the invention is a non-silicon defoaming agent, is not easy to remain, is suitable for the production process of the PCB, has good defoaming and foam inhibiting capabilities, and meets the requirements of the PCB developing process. In addition, the preparation method of the defoaming agent provided by the invention is simple in process, does not need special synthesis equipment or a reaction kettle, only needs to continuously stir and heat to 75-85 ℃ in the preparation process, and is simple in steps and low in cost of input equipment and labor.

Detailed Description

The non-silicon defoaming agent for the developing solution of the printed circuit board comprises the following components: 250 portions of tributyl phosphate, 200 portions of ethylene glycol, 200 portions of propylene glycol block polyether, 20 to 50 portions of thickening agent, 5 to 15 portions of emulsifying agent, 5 to 15 portions of glycerin monostearate and 70 to 520 portions of pure water.

Example 1

The component proportions of the non-silicon defoamer for the developing solution of the printed circuit board in the embodiment are shown in table 1, wherein the propylene glycol block polyether added in the embodiment is polyether L61, the thickener added in the embodiment is soluble starch, and the emulsifier added in the embodiment is tween 60.

The preparation process of the developing solution for the printed circuit board in the embodiment is as follows:

s1, weighing tributyl phosphate and ethylene glycol according to the weight ratio, adding the tributyl phosphate and the ethylene glycol into the reaction vessel, and continuously stirring until the mixed solution in the reaction vessel is clear and has no layering;

s2, adding propylene glycol block polyether and a thickening agent into the reaction vessel, and continuously stirring until the mixed solution in the reaction vessel is clear and has no layering;

s3, continuously adding the emulsifier and the glyceryl monostearate into the reaction vessel, heating to 80 ℃ under the stirring condition to completely dissolve the emulsifier, wherein the mixed solution in the reaction vessel is clear and has no layering;

s4, slowly adding pure water with the volume fraction of 1/3 and the temperature of 80 ℃ into the reaction container, and continuously stirring to obtain a water-in-oil type transparent paste;

s5, adding the residual 2/3 pure water with the temperature of 80 ℃ into the reaction container, naturally cooling to 60 ℃ under the stirring condition, converting the water-in-oil type transparent paste in the reaction container into oil-in-water type emulsion, and cooling to room temperature to obtain the non-silicon defoaming agent.

Example 2

The component ratio of the non-silicon defoamer for the developing solution of the printed circuit board in the embodiment is shown in table 1, wherein the propylene glycol block polyether added in the embodiment is polyether L62, the thickening agent added in the embodiment is acacia, and the emulsifier added in the embodiment is tween 60.

The developer for printed circuit board in this example was prepared in accordance with example 1.

Example 3

The component proportions of the non-silicon defoamer for the developing solution of the printed circuit board in the embodiment are shown in table 1, wherein the propylene glycol block polyether added in the embodiment is polyether L63, the thickener added in the embodiment is sodium polyacrylate, and the emulsifier added in the embodiment is span 60.

The developer for printed circuit board in this example was prepared in accordance with example 1.

Example 4

The component proportions of the non-silicon defoamer for the developing solution of the printed circuit board in the embodiment are shown in table 1, wherein the propylene glycol block polyether added in the embodiment is polyether L64, the thickening agent added in the embodiment is polyvinylpyrrolidone, and the emulsifier added in the embodiment is span 60.

The developer for printed circuit board in this example was prepared in accordance with example 1.

Example 5

The component proportions of the non-silicon defoamer for the developing solution of the printed circuit board in the embodiment are shown in table 1, wherein the propylene glycol block polyether added in the embodiment is polyether L65, the thickener added in the embodiment is soluble starch, and the emulsifier added in the embodiment is tween 60.

The developer for printed circuit board in this example was prepared in accordance with example 1.

TABLE 1

Item	Example 1	Example 2	Example 3	Example 4	Example 5
						Tributyl phosphate	150 portions of	250 portions of	200 portions of	220 portions of	180 portions of
Ethylene glycol	100 portions of	200 portions of	150 portions of	180 portions of	200 portions of
						Propylene glycol block polyethers	200 portions of	400 portions of	300 portions of	350 parts of	300 portions of
Thickening agent	20 portions of	50 portions of	30 portions of	40 portions of	40 portions of
						Emulsifier	5 portions of	15 portions of	10 portions of	10 portions of	5 portions of
Glyceryl monostearate	5 portions of	15 portions of	10 portions of	10 portions of	10 portions of
						Pure water	520 parts of	70 portions of	300 portions of	190 portions of	265 portions of

In the invention, the defoaming and foam inhibiting capabilities of the non-silicon defoaming agent for the developing solution of the printed circuit board prepared in the embodiments 1 to 5 are evaluated through the defoaming property test of the developing solution of the PCB, and the specific test method is as follows:

firstly, preparing a test solution. To a 1% by mass aqueous solution of sodium carbonate (100 parts by mass) was added 0.05 part of the non-silicon defoaming agent for a printed wiring board developer prepared in examples 1 to 5, respectively, to prepare a developer. And respectively dissolving the unexposed dry film of the photoresist layer in the prepared developing solution to enable the concentration of the unexposed dry film of the photoresist layer to reach 0.5g/L, thus obtaining the required test solution.

And secondly, defoaming property test. 50mL of the above test solution was added to a measuring cylinder with a ground glass plug having a capacity of 100 mL, and the mixture was shaken for 50 times for 1 minute and then left to stand, and the state of foam was observed, and the defoaming property was evaluated according to the following criteria:

o: the foam disappears when the time is less than 15 seconds, and the defoaming and foam inhibiting capabilities are good;

and (delta): in 15-60 seconds, the foam disappears, and the defoaming and foam inhibiting capabilities are common;

gamma rays: when the time exceeds 60 seconds, the foam disappears or does not disappear, and the defoaming and foam suppressing capabilities are poor.

The specific test results are shown in table 2.

TABLE 2

	Results of defoaming Property test
		Example 1	○
Example 2	○
		Example 3	○
Example 4	○
		Example 5	○

From the test results in table 2, it can be seen that the defoaming agents prepared in the embodiments 1 to 5 of the present invention belong to non-silicon defoaming agents, exhibit good defoaming and foam inhibiting capabilities in the defoaming test of the PCB developer, and have the advantages of simple preparation method, no need of special synthesis equipment and reaction kettle, and suitability for the development process of the printed circuit board.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.

Claims (7)

1. The non-silicon defoaming agent for the developing solution of the printed circuit board is characterized by comprising the following components in parts by weight: 250 portions of tributyl phosphate, 200 portions of ethylene glycol, 200 portions of propylene glycol block polyether, 20 to 50 portions of thickening agent, 5 to 15 portions of emulsifying agent, 5 to 15 portions of glycerin monostearate and 70 to 520 portions of pure water.

2. The non-silicon defoaming agent for printed circuit board developer according to claim 1, wherein the propylene glycol block polyether is a block polymer synthesized by addition polymerization of propylene glycol as an initiator and an epoxide under the action of a catalyst.

3. The non-silicon defoaming agent for printed circuit board developer according to claim 2, wherein the epoxide is one or both of polyoxyethylene and polypropylene.

4. The non-silicon defoamer for developer solution for printed circuit boards as claimed in claim 2 or 3, wherein the molecular weight of the propylene glycol block polyether is 2000-3000.

5. The non-silicon defoaming agent for printed circuit board developer according to claim 1, wherein the thickener is any one of soluble starch, gum arabic, sodium polyacrylate and polyvinylpyrrolidone.

6. The non-silicon defoamer for printed circuit board developer according to claim 1, wherein the emulsifier is tween 60 or span 60.

7. The method for preparing the non-silicon defoaming agent for the developing solution of the printed circuit board according to claim 1, comprising the steps of:

s1, weighing tributyl phosphate and ethylene glycol according to the weight ratio, adding the tributyl phosphate and the ethylene glycol into the reaction vessel, and continuously stirring until the mixed solution in the reaction vessel is clear and has no layering;

s2, adding propylene glycol block polyether and a thickening agent into the reaction vessel, and continuously stirring until the mixed solution in the reaction vessel is clear and has no layering;

s3, continuously adding the emulsifier and the glyceryl monostearate into the reaction vessel, heating to 75-85 ℃ under the stirring condition to completely dissolve the emulsifier, wherein the mixed solution in the reaction vessel is clear and has no layering;

s4, slowly adding 1/3 volume percent of pure water at the temperature of 75-85 ℃ into the reaction container, and continuously stirring to obtain a water-in-oil type transparent paste;

s5, adding the residual 2/3 pure water with the temperature of 75-85 ℃ into the reaction vessel, naturally cooling to 60 ℃ under the stirring condition, converting the water-in-oil type transparent paste in the reaction vessel into oil-in-water type emulsion, and cooling to room temperature to obtain the non-silicon defoaming agent.