CN110330867B

CN110330867B - Epoxy modified acrylic resin composition and processing method applied to metal substrate

Info

Publication number: CN110330867B
Application number: CN201910614600.XA
Authority: CN
Inventors: 丘威平; 谭小林; 王远; 陈毅龙; 吴彪
Original assignee: Kinwong Electronic Technology Longchuan Co Ltd
Current assignee: Kinwong Electronic Technology Longchuan Co Ltd
Priority date: 2019-07-08
Filing date: 2019-07-08
Publication date: 2021-03-30
Anticipated expiration: 2039-07-08
Also published as: CN110330867A

Abstract

The invention discloses an epoxy modified acrylic resin composition and a processing method applied to a metal substrate, wherein the resin composition comprises the following components in parts by weight: 40-60 parts by weight of epoxy modified acrylic resin prepolymer; 5-15 parts of reactive diluent; 0.01-0.05 part by weight of an ultraviolet initiator; 2-5 parts by weight of a crosslinking agent; 0.05-0.1 part by weight of a polymerization inhibitor; 0.5-2 parts of an auxiliary agent; 20-40 parts by weight of a filler; the components are mixed according to the proportion, dispersed and mixed by adopting high-speed shearing and stirring, and the required epoxy modified acrylate resin composition is prepared by standing and defoaming treatment. After the composition containing the epoxy modified acrylate resin is cured by UV light, the hardness, acid and alkali etching resistance, high temperature resistance and adhesion with the surface of a metal substrate of a cured product are all superior to those of a traditional protective film, the risk of scratching can be reduced, and meanwhile, the bonding force between an epoxy layer and a metal surface is improved, so that the epoxy layer and the metal surface are tightly bonded.

Description

Epoxy modified acrylic resin composition and processing method applied to metal substrate

Technical Field

The invention relates to the field of printed circuit boards, relates to a composition containing epoxy resin modified acrylic resin, and provides a method for preventing metal base surface from being corroded by acid and alkali by using the resin composition to replace a protective film in the processing of PCB of a metal base copper-clad plate.

Background

The metal-based copper clad laminate is one of copper clad laminates, and is widely applied to the fields of LEDs and high-power modules due to good heat dissipation performance. Generally, the commonly used metal base is aluminum or copper, which are metal materials with strong activity and can chemically react with acid and alkali, so that a protective film needs to be attached to a metal surface (non-circuit surface) in the processing process of the current PCB of the metal-base copper-clad plate to protect the metal surface from being corroded by the acid, the alkali and the like which are contacted in the processing process of the PCB. Traditional pad pasting technology needs manual to the metal covering pad pasting, adopts present automatic pad pasting machine, and the per minute can paste 2 ~ 3, and efficiency is lower, and aluminum plate is unprocessed moreover, and tiny particle metal fillings impurity etc. can remain between membrane and metal covering, when carrying out PCB man-hour, can fish tail aluminium face or rip the protection film by pressure, and the aluminium face is destroyed by acid, alkali.

In the prior art, for example, in patent CN201720586751, an aluminum substrate film pasting device is designed to perform dust absorption cleaning on an aluminum plate surface to reduce the risk of damage of a protective film, but the method is not much different from the conventional manual film pasting, and only uses compressed air to blow, static electricity removal to clean a metal surface, which is not as good as the cleaning effect of polishing, oil removal and water washing of a horizontal pretreatment line, and still cannot solve the defect of low efficiency of a film pasting process.

In addition, the adopted protective film is usually a thermoplastic PET or PVC film, the heat resistance of the protective film is not high, and meanwhile, the protective film needs to be adhered by a layer of glue coated on the surface of the protective film, and in the tin spraying process, the film is melted and the glue layer is not adhered and falls off due to overlong high temperature, so that the production of the subsequent working section is influenced; the protective film is soft, and is easy to scratch in the production process, so that the aluminum surface is corroded by acid and alkali to form deep corrosion marks which can be removed only by deep polishing; the unit price of the protective film is higher, and the quality of products on the market is uneven.

After the metal substrate finishes the PCB process, a large amount of manual film tearing needs to be removed, the film is very strong in adhesion, cannot be torn off easily, and is low in efficiency. If the film adhesion is reduced, the metal base edge is liable to penetrate into the etching solution, causing edge corrosion. In patent CN201720122769, an automatic film tearing machine is designed, which can realize automatic film peeling and rolling and improve film tearing efficiency to a certain extent compared with manual film tearing. In practical use, however, the thin metal substrate is easy to bend and deform; if the protective film is highly tacky, there will be incomplete peeling. In the actual use process of the equipment, the protection film still needs to be manually torn into a corner first, and the machine can clamp the protection film to tear the film.

In summary, the existing film pasting process is high in labor and material cost and low in efficiency, and the process is difficult to realize automatic production.

Although some manufacturers adopt the coating of the epoxy resin composition as a protective layer to replace a film pasting process, the epoxy resin can be cured at high temperature, the curing time is long, and the requirements on equipment and sites are high, so that the epoxy resin can be cured only by a single coating process, and the risk of metal surface corrosion caused by the fact that some local areas cannot be completely covered by the resin exists.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

For the reasons, the applicant proposes an epoxy modified acrylic resin composition and a processing method applied to a metal substrate, aiming at solving the following problems: 1. after the common acrylate resin is cured by UV, the surface hardness is not enough and the common acrylate resin is easy to scratch, an epoxy chain segment is introduced for copolymerization modification, and the hardness, heat resistance and acid-base corrosion resistance of a cured product are all superior to those of a common protective film and are equivalent to those of thermosetting epoxy;

2. UV normal temperature rapid curing is adopted, the equipment volume is small, multiple coating can be realized, and the production efficiency and the reliability of a protective layer are improved;

3. the manufacturing cost of the product is reduced;

4. the problem of low efficiency is solved without a manual film pasting process;

5. the surface pretreatment of the aluminum plate is adopted to remove residual particles and oil stains on the surface, so that the risk of metal surface corrosion caused by the easy damage of a protective layer is reduced;

6. after the PCB manufacturing process is finished, the manual film tearing process can be omitted, and the problem of low efficiency is solved;

7. the automatic production is realized, the personnel operation is reduced, the reliability of the metal substrate protective layer of the product quality is improved, the production efficiency is improved, the product quality is improved, and the like.

Disclosure of Invention

In order to satisfy the above requirements, a first object of the present invention is to provide an epoxy-modified acrylic resin composition.

A second object of the present invention is to provide a method for processing a metal-based PCB based on the resin composition.

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

the epoxy modified acrylic resin composition comprises the following components in parts by weight:

40-60 parts by weight of epoxy modified acrylic resin prepolymer;

5-15 parts of reactive diluent;

0.01-0.05 part by weight of an ultraviolet initiator;

2-5 parts by weight of a crosslinking agent;

0.05-0.1 part by weight of a polymerization inhibitor;

0.5-2 parts of an auxiliary agent;

20-40 parts by weight of a filler;

the epoxy modified acrylic resin prepolymer is one or more of bisphenol A type epoxy modified acrylic resin and phenolic aldehyde type epoxy modified acrylic resin;

the active diluent is one or more of methyl acrylate, isooctyl acrylate and n-butyl acrylate;

the ultraviolet initiator is one or more of benzoin, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin butyl ether; or the ultraviolet light initiator is one or more of diphenylethanone, alpha-dimethoxy-alpha-phenylacetophenone; or the ultraviolet initiator is one or more of alpha, alpha-diethoxyacetophenone, alpha-hydroxyalkyl benzophenone and alpha-aminoalkyl benzophenone;

the cross-linking agent is one or more of trimethylolpropane triacrylate, tripropylene glycol diacrylate and ethylene glycol diacrylate;

the polymerization inhibitor is one or more of hydroquinone and hydroquinone methyl ether;

the auxiliary agent is one or more of a defoaming agent and a flatting agent;

the filler is one or more of sheet talcum powder, spherical silicon dioxide, boron nitride, alumina, aluminum hydroxide, boehmite, zinc oxide and magnesium oxide;

the components are mixed according to the proportion, dispersed and mixed by adopting high-speed shearing and stirring, and the required epoxy modified acrylate resin composition is prepared by standing and defoaming treatment.

The technical scheme is that the viscosity of the epoxy modified acrylate resin composition is 5000-7000 cps.

The further technical scheme is that the particle size of the filler is 3-5 mu m.

The invention also discloses a processing method of the metal-based PCB based on the resin composition, and the epoxy modified acrylic acid-containing resin composition based on any one of the above steps comprises the following steps:

step S1, performing edging and chamfering treatment on the metal substrate needing film covering protection, polishing and deoiling the surface of the metal substrate through a horizontal pretreatment line, and performing washing and drying treatment to obtain a treated metal substrate;

step S2, uniformly coating the epoxy modified acrylic acid-containing resin composition on the surface of the metal substrate to be protected by a coating machine, irradiating the metal substrate by a UV lamp to cure the epoxy modified acrylic acid-containing resin composition, coating and curing again to form a hard protective layer on the surface of the metal substrate, and performing subsequent PCB (printed Circuit Board) processing operation on the metal substrate with the protective layer;

step S3, after the metal substrate completes the PCB process, the metal substrate is polished by a horizontal abrasive belt machine, the circuit surface of the metal substrate is upward to polish the board and remove the protective layer, the metal substrate is conveyed by adopting a soft rubber line roller type conveying mode, an abrasive belt for polishing and brushing is arranged below the metal substrate, and the metal substrate is washed by water to remove abrasive dust.

The step S2 further includes that the single-pass coating thickness of the epoxy-modified acrylic-containing resin composition is 10 to 20 μm.

The further technical scheme is that the step S2 further includes that the thickness of the protective layer is 25-35 μm.

The technical scheme is that the step S3 further includes that the horizontal belt sander polishes with a 320-mesh grinding wheel and a 600-mesh grinding wheel.

The further technical scheme is that the step S3 further includes flushing corners with high-pressure water in the process of brushing by using a water circulation filtering system to reduce the residue of abrasive dust.

Compared with the prior art, the invention has the beneficial effects that: after the composition containing the epoxy modified acrylate resin is cured by UV light, the hardness, acid and alkali etching resistance and high temperature resistance of a cured product and the adhesion with the surface of a metal substrate are all superior to those of a traditional protective film and are equivalent to those of common thermosetting epoxy resin; in the PCB processing process, by adopting special metal substrate surface pretreatment, small particle impurities, oil stains and the like are removed, the risk of scratching can be reduced, and meanwhile, the binding force between the epoxy layer and the metal surface is improved, so that the epoxy layer and the metal surface are tightly bound; in the processing method of the metal substrate, the designed metal base surface protective layer can be removed by adopting horizontal automatic abrasive belt grinding plate line grinding instead of manual film tearing, and the efficiency and the automation degree are higher.

The invention is further described below with reference to the accompanying drawings and specific embodiments.

Drawings

FIG. 1 is a schematic flow chart illustrating one embodiment of a method for processing a metal-based PCB based on a resin composition according to the present invention;

FIG. 2 is a schematic view of the main structure of the coating machine in the flow chart of FIG. 1;

FIG. 3 is a left side view of the applicator roll construction of FIG. 2;

FIG. 4 is a schematic view of the main structure of a horizontal belt sander in the grinding step of the flowchart of FIG. 1;

FIG. 5 is a schematic table of an example of the components of the epoxy-modified acrylic resin composition of the present invention;

fig. 6 is a test result of the performance of the different components of the embodiment of fig. 5 with respect to the protective layer.

Reference numerals

1 metal substrate 2 UV exposure machine

3 lower roller 4 transfer roller

5 upper roller 6 UV glue solution

8600-mesh grinding wheel with 7 high-pressure water spray nozzles

9320 mesh emery wheel 10 soft rubber press roller

11 protective layer

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.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be connected or detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., 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 should not be understood to 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. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

The invention discloses a resin composition containing epoxy modified acrylic acid, which comprises the following components in parts by weight:

40-60 parts by weight of epoxy modified acrylic resin prepolymer;

5-15 parts of reactive diluent;

0.01-0.05 part by weight of an ultraviolet initiator;

2-5 parts by weight of a crosslinking agent;

0.05-0.1 part by weight of a polymerization inhibitor;

0.5-2 parts of an auxiliary agent;

20-40 parts by weight of a filler;

the auxiliary agent is one or more of a defoaming agent and a flatting agent;

The uv initiator may be selected from, but not limited to, the types mentioned above, and other types or combinations of benzoin and derivatives, benzil, and alkyl benzophenones may be selected, which are given as examples only and are not intended to be illustrative or implied as limiting.

Specifically, compared with the common acrylate resin, the common acrylate resin is not enough in surface hardness and is easy to scratch after being subjected to UV curing, and the epoxy modified acrylate resin of the scheme introduces an epoxy chain segment for copolymerization modification, so that the hardness, heat resistance and acid-base corrosion resistance of a cured product of the epoxy modified acrylate resin are superior to those of a common protective film, are equivalent to those of thermosetting epoxy, and are specifically applied to the following metal substrate processing method.

Preferably, the viscosity of the epoxy modified acrylate resin composition is 5000 to 7000 cps.

Preferably, the particle size of the filler is 3-5 μm.

Specifically, the processing flow chart shown in FIG. 1 is a detailed flow chart of the above steps S1-S3, and the UV curable resin compound is the epoxy-modified acrylic acid-containing resin composition described in the above steps S1-S3.

As shown in fig. 2 and 3, in the above steps S1-S3, the coating operation is schematically shown, after the metal substrate 1 is subjected to the UV roll coating structure, the surface of the metal substrate 1 is covered with a protective layer 11 made of the epoxy-modified acrylic-containing resin composition, and then UV exposure machine 2 irradiates it with UV lamp radiation to UV cure it, as shown in fig. 2 and 3, the process is circulated at least twice for the epoxy-modified acrylic-containing resin composition to achieve the final object of the present invention;

specifically, as shown in fig. 3, the roller coating structure comprises an upper roller 5, a transfer roller 4 located at the side of the upper roller, a UV glue solution 6 arranged between the upper roller 5 and the transfer roller 4, and a lower roller 3 located below the transfer roller 4; the UV glue solution 6 is used for UV curing of the protective layer 11 made of the epoxy-modified acrylic resin composition.

In the embodiment shown in fig. 2 and 3, the step S2 further includes that the thickness of the epoxy-modified acrylic resin composition in one coating step is 10-20 μm, which is the thickness in one coating step, and the value can be adjusted in two coating steps.

In the embodiment shown in fig. 2 and fig. 3, the step S2 further includes that the thickness of the protection layer is 25-35 μm.

In the embodiment shown in fig. 4, the step S3 further includes that the horizontal belt sander uses a 320-mesh grinding wheel 9 and a 600-mesh grinding wheel 8 to perform grinding, so as to remove the protective layer below the metal substrate 1, so as to facilitate the normal operation of the subsequent metal substrate 1.

Specifically, horizontal abrasive band machine includes, and a plurality of flexible glue is pressed rumble 10, is located the flexible glue and is pressed 320 meshes emery wheel 9 and 600 meshes emery wheel 8 of rumble 10 below to and water under high pressure shower nozzle 7, utilize water circulation filtration system to use the water under high pressure (spout through water under high pressure shower nozzle 7) to erode each corner of metal substrate 1 and equipment at the scrubbing process, be used for reducing the abrasive dust and remain.

Referring to fig. 5 and 6, the test results of the performance of the different components of the protective layer are as follows:

testing the viscosity of the mixed composition by using a rotational viscometer;

testing the surface hardness of the cured product by using a pencil hardness tester;

adopting a PCB circuit etching line to simulate the production process and testing the acid and alkali etching resistance of the protective film;

and (3) carrying out wet grinding by adopting a 320-mesh abrasive belt wheel and a 600-mesh abrasive belt wheel, and testing the times for grinding the protective layer.

The test results of the first embodiment, the second embodiment and the third embodiment show that the excessive content of the monomer affects the compactness of the cured film, and causes poor acid and alkali resistance; with the increase of the proportion of the epoxy modified acrylic resin prepolymer, after the composition is cured, the hardness is improved, the compactness is improved, the acid and alkali resistance is good, but the composition is more difficult to remove by belt grinding.

Example four has higher filler content, higher surface hardness, and is more scratch resistant than example two, but is also less susceptible to removal by grinding.

The test results of example two, comparative example one and comparative example two show that as the content of the polyfunctional crosslinking agent increases, the hardness of the cured product tends to increase, but the cured product is more difficult to abrade. Meanwhile, the film has too high hardness and large brittleness, and cracks are easy to appear by slight bending, so that the risk of leakage of the etching solution is caused.

Combining the above data, the component ratios determined in example two were used as the optimum formulation for the epoxy-modified acrylic resin composition.

In conclusion, after the composition containing the epoxy modified acrylate resin is cured by UV light, the hardness, acid and alkali etching resistance, high temperature resistance and adhesion with the surface of a metal substrate of a cured product are superior to those of a traditional protective film and are equivalent to those of common thermosetting epoxy resin; in the PCB processing process, by adopting special metal substrate surface pretreatment, small particle impurities, oil stains and the like are removed, the risk of scratching can be reduced, and meanwhile, the binding force between the epoxy layer and the metal surface is improved, so that the epoxy layer and the metal surface are tightly bound; in the processing method of the metal substrate, the designed metal base surface protective layer can be removed by adopting horizontal automatic abrasive belt grinding plate line grinding instead of manual film tearing, and the efficiency and the automation degree are higher.

Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes should fall within the scope of the claims of the present invention.

Claims

1. The epoxy modified acrylic resin composition is characterized by comprising the following components in parts by weight:

40-60 parts by weight of epoxy modified acrylic resin prepolymer;

5-15 parts of reactive diluent;

0.01-0.05 part by weight of an ultraviolet initiator;

2-5 parts by weight of a crosslinking agent;

0.05-0.1 part by weight of a polymerization inhibitor;

0.5-2 parts of an auxiliary agent;

20-40 parts by weight of a filler;

the auxiliary agent is one or more of a defoaming agent and a flatting agent;

2. The epoxy-modified acrylic-containing resin composition according to claim 1, wherein the viscosity of the epoxy-modified acrylate resin composition is 5000 to 7000 cps.

3. The epoxy-modified acrylic-containing resin composition according to claim 1, wherein the filler has a particle size of 3 to 5 μm.

4. A method for processing a metal-based PCB based on a resin composition, wherein the epoxy-modified acrylic acid-containing resin composition according to any one of claims 1 to 3 comprises the steps of:

5. The method for processing a metal-based PCB based on a resin composition as recited in claim 4, wherein the step S2 further comprises the step of coating the epoxy modified acrylic acid containing resin composition with a thickness of 10-20 μm in one pass.

6. The method as claimed in claim 4, wherein the step S2 further includes a step of forming the protective layer with a thickness of 25-35 μm.

7. The method for processing a metal-based PCB based on a resin composition as claimed in claim 4, wherein the step S3 further comprises the step of grinding the metal-based PCB with a 320-mesh grinding wheel and a 600-mesh grinding wheel by a horizontal belt sander.

8. The method for processing a metal-based PCB based on a resin composition as claimed in claim 4, wherein the step S3 further comprises washing corners with high pressure water during the brushing process using a water circulation filtering system for reducing the residue of abrasion dust.