1. A preparation method of aqueous temporary protective resin applied to a PCB circuit board is characterized by comprising the following steps: the method comprises the following steps:

step 1: adding 50% of emulsifier and 30% of water into a pre-emulsification cylinder, and uniformly stirring for 15 min;

step 2: adding all monomers under high-speed stirring based on Step1, and pre-emulsifying for 30min to obtain pre-emulsion;

step 3: when the appearance is milk white, adding 50% of initiator, and stirring uniformly for 8-12min to obtain a mixture;

step 4: taking out 10% of the pre-emulsion, putting into a reaction kettle, adding the rest emulsifier and water, and uniformly stirring to obtain a further mixture;

step 5: heating, adding the rest of initiator, and keeping the temperature at 80-85 ℃ for 30min to carry out seed polymerization;

step 6: based on the Step5, after 30min, the residual pre-emulsion is dripped at the temperature of 80-85 ℃, the dripping time is 3h, and the temperature is kept at 85-90 ℃ after the dripping is finished;

step 7: cooling after heat preservation, and adding a neutralizer;

step 8: filtering and discharging to obtain the waterborne temporary protective resin which is required to be applied to the PCB.

2. The method for preparing an aqueous temporary protective resin for PCB circuit board according to claim 1, wherein the protective resin comprises DAP 5-15%, St 35-45%, BA 5-15%, AA 1-2%, H5-15% by weight₂35-40% of O, 1-2% of emulsifier, 0.3-0.8% of initiator and 1-2% of neutralizer.

3. The method for preparing an aqueous temporary protective resin for PCB circuit board as claimed in claim 2, wherein the temperature of the mixture in Step5 is 70 ℃.

4. The method for preparing the aqueous temporary protective resin for the PCB of claim 3, wherein the temperature is maintained at 85-90 ℃ for 1.5h after the residual pre-emulsion in Step6 is added dropwise.

5. The method for preparing an aqueous temporary protective resin for PCB circuit board as claimed in claim 4, wherein the cooling temperature in Step7 is decreased to 60 ℃.

6. The method for preparing an aqueous temporary protective resin for PCB circuit board as claimed in claim 5, wherein said temporary protective resin is filtered in Step8 with a filtering precision of 300 mesh.

Background

In the traditional PCB manufacturing process, the surface pretreatment is basically carried out firstly, namely, the metal oxide film is removed by adopting the processes of polishing, pickling, washing, drying and the like so as to reduce the reject ratio of products and improve the quality of the products, but the process not only consumes time, but also causes a great deal of resource waste and environmental pollution;

in the market, the waterborne temporary protective resin is less, the performance is poorer, and the main characteristics are that the solid content is relatively low, most of the waterborne temporary protective resin is 30-40%, the coating thickness is insufficient, the stripping process is easy to break, the external impact and scratch resistance cannot be well relieved, the waterborne strippable resin on the market is generally slow in drying speed, the surface drying time is 30 minutes or even longer, and the waterborne strippable resin cannot be stripped after one day or even longer, so that the timeliness of production and processing is seriously influenced.

Disclosure of Invention

The invention aims to provide a preparation method of an aqueous temporary protective resin applied to a PCB (printed circuit board), so as to solve the problems in the background.

In order to solve the technical problems, the invention is realized by the following technical scheme:

the invention relates to a preparation method of waterborne temporary protective resin applied to a PCB (printed circuit board), which comprises the following steps:

step 1: adding 50% of emulsifier and 30% of water into a pre-emulsification cylinder, and uniformly stirring for 15 min;

step 2: adding all monomers under high-speed stirring based on Step1, and pre-emulsifying for 30min to obtain pre-emulsion;

step 3: when the appearance is milk white, adding 50% of initiator, and stirring uniformly for 8-12min to obtain a mixture;

step 4: taking out 10% of the pre-emulsion, putting into a reaction kettle, adding the rest emulsifier and water, and uniformly stirring to obtain a further mixture;

step 5: heating, adding the rest of initiator, and keeping the temperature at 80-85 ℃ for 30min to carry out seed polymerization;

step 6: based on the Step5, after 30min, the residual pre-emulsion is dripped at the temperature of 80-85 ℃, the dripping time is 3h, and the temperature is kept at 85-90 ℃ after the dripping is finished;

step 7: cooling after heat preservation, and adding a neutralizer;

step 8: filtering and discharging to obtain the waterborne temporary protective resin which is required to be applied to the PCB.

Preferably, the protective resin comprises, in percent, DAP 5-15%, St 35-45%, BA 5-15%, AA 1-2%, H₂35-40% of O, 1-2% of emulsifier, 0.3-0.8% of initiator and 1-2% of neutralizer.

Preferably, the temperature of the mixture in Step5 is increased to 70 ℃.

Preferably, after the residual pre-emulsion in Step6 is added dropwise, the temperature is kept at 85-90 ℃ for 1.5 h.

Preferably, the temperature of the temperature reduction in Step7 is reduced to 60 ℃.

Preferably, the temporary protection resin is filtered in Step8, and the filtering precision is 300 meshes.

The invention has the following beneficial effects:

according to the waterborne temporary protection resin for the PCB, the drying speed and the thickness of the coating are improved by adopting a formula and a process design with high solid content and small particle size, the DAP functional monomer is introduced to improve the hot-adhesion and cold-brittleness characteristics of the acrylic resin, so that the coating has flexibility and hardness, the coating has good strippability and anti-adhesion property, and styrene is adopted to replace methyl methacrylate to reduce the cost and the adhesive force to a base material, so that the strippability is better improved.

According to the preparation method of the waterborne temporary protective resin applied to the PCB, the waterborne temporary protective resin is sprayed one more time after the copper foil is pressed, and after the paint film is dried, the paint film is torn off when needed, so that the next procedure can be carried out instead of a surface pretreatment process, the working time can be saved, the efficiency can be improved, and the waste of resources and the environmental pollution can be reduced.

Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of a method for preparing an aqueous temporary protective resin for PCB circuit boards according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

Please refer to fig. 1: the invention relates to a preparation method of waterborne temporary protective resin applied to a PCB (printed circuit board), which comprises the following steps:

step 1: adding 50% of emulsifier and 30% of water into a pre-emulsification cylinder, and uniformly stirring for 15 min;

step 2: adding all monomers under high-speed stirring based on Step1, and pre-emulsifying for 30min to obtain pre-emulsion;

step 3: when the appearance is milk white, adding 50% of initiator, and stirring uniformly for 8-12min to obtain a mixture;

step 4: taking out 10% of the pre-emulsion, putting into a reaction kettle, adding the rest emulsifier and water, and uniformly stirring to obtain a further mixture;

step 5: heating, adding the rest of initiator, and keeping the temperature at 80-85 ℃ for 30min to carry out seed polymerization;

step 6: based on the Step5, after 30min, the residual pre-emulsion is dripped at the temperature of 80-85 ℃, the dripping time is 3h, and the temperature is kept at 85-90 ℃ after the dripping is finished;

step 7: cooling after heat preservation, and adding a neutralizer;

step 8: filtering and discharging to obtain the waterborne temporary protective resin which is required to be applied to the PCB.

Wherein the protective resin comprises, by percentage, 5-15% of DAP, 35-45% of St, 5-15% of BA, 1-2% of AA, and H₂35-40% of O, 1-2% of emulsifier, 0.3-0.8% of initiator and 1-2% of neutralizer.

Wherein the temperature of the mixture in Step5 is increased to 70 ℃.

Wherein, the temperature is kept at 85-90 ℃ for 1.5h after the residual pre-emulsion in Step6 is added dropwise.

Wherein the temperature of the Step7 is reduced to 60 ℃.

In Step8, the temporary protection resin is filtered, and the filtering precision is 300 meshes.

The aqueous temporary protection resin in the scheme meets the following performances:

peeling property: the strippable coating is a temporary protective coating, when a protected object needs to be put into use, a coating film needs to be completely torn off, no residue exists on the surface of the object, and the appearance of the object is not influenced, so that the water-based strippable resin is required to have good strippability, the adhesive force of the water-based strippable resin is moderate, the excessively high adhesive force is not beneficial to the stripping of the coating film, and the excessively low adhesive force is not beneficial to the corrosion prevention of the coating film;

cohesion: one of the characteristics of the water-based strippable resin, which is different from the traditional resin emulsion, is that the water-based strippable resin has stronger cohesive force after film forming, a coating film is stretched to a position far away from a substrate when being stripped, the film is continuously kept without breaking, if the strength of the coating film is not enough, the film is likely to break or be broken into small pieces when being stripped, the coating film can not achieve the strippable effect, the strength of the coating film of the water-based strippable resin is influenced by the thickness of the coating film, if the dried coating film is not thick enough, the coating film is broken into small pieces when being stripped, and 25 mu m is the minimum thickness of most strippable coatings which can be stripped from the substrate;

corrosion resistance and stain removal: the strippable paint has both corrosion resistance and stain removal property, and is not used according to different use purposes, so that the strippable anticorrosive paint and the strippable stain removal paint appear.

Example two

Referring to the preparation scheme of example one, the specific experimental procedure is as follows (data units in the table are%):

	①	②	③
				DAP	6	10	14
St	40	40	40
				BA	14	10	6
AA	1	1	1
				emulsifier	1	1	1
H2O	36.5	36.5	36.5
				Initiator	0.5	0.5	0.5
Neutralizing agent	1	1	1

Through the process, the water-based temporary protection resin is prepared by synthesizing the raw materials according to the mixture ratio of the raw materials in the table, and the water-based temporary protection ink is prepared, and has the following specific properties:

as can be seen from the table, the synthesized waterborne temporary protective resin has good application property and excellent performance, and has strong popularization value.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.