PCB through hole plugging resin and preparation method and application thereof

Abstract

The invention discloses PCB (printed circuit board) through hole plugging resin which is prepared from the following raw materials in parts by weight: 35-100 parts of epoxy resin composition, 5-15 parts of curing agent, 1-10 parts of curing accelerator and 0.1-5 parts of assistant. By adopting the combination of the bisphenol A epoxy resin, the bisphenol F epoxy resin and the trifunctional epoxy resin, the prepared hole plugging resin is easy to plug holes, not easy to sag and excellent in hole plugging performance. The thermosetting resin composition is used for permanently filling the through hole in the printed circuit board, has the properties of low viscosity, easiness in hole filling, good sagging resistance and high glass transition temperature, not only can meet the requirements of an existing vacuum hole filling machine, but also can meet the hole filling requirements on high efficiency and high cost performance in a complex printed circuit board.

Description

Technical Field

[0001] The invention relates to the field of polymer compound compositions, and in particular to a PCB through-hole plugging resin and a preparation method and application thereof. Background Art

[0002] With the development and progress of science and technology, electronic products are gradually developing in the direction of light, thin and small. PCB (printed circuit board) boards need to meet the requirements of high precision, high density and high difficulty. The thickness of PCB boards continues to increase. In order to meet the needs of integration, the maximum thickness-to-diameter ratio has reached 40:1. In order to ensure the integrity of the via signal, back drilling technology is widely used. In order to solve the problems that cannot be solved by green oil plugging or press-fit filling resin, a new plugging process has been developed. The existing resin plugging processes include screen printing machine plugging and vacuum plugging. Screen printing machine plugging has low investment cost and high production efficiency, but there are problems such as poor pad flatness, easy to have voids and bubbles; vacuum plugging has high cost, high anti-sagging requirements and difficult to clean the board surface resin. Therefore, it is very important to develop a plugging resin that is easy to plug, has good sag properties, and is easy to clean the board surface resin.

[0003] Chinese invention patent CN115612246A discloses a composition for forming PCB plugging resin, as well as a preparation method, application, and filling process. The synergistic effect of benzoxazine with a viscosity of 5000mPa·s and epoxy resin with a viscosity of 10000mPa·s is used to form a PCB plugging resin composition, which can improve the problem of PCB plugging resin solidification depression, but it is not easy to plug the hole, and the excess material after plugging is not easy to polish. Chinese invention patent CN115216117B discloses a modified plugging resin for circuit boards and a preparation method thereof. The prepared plugging resin material is positively charged, and the negatively charged colloidal palladium is easily adsorbed on the surface, which can increase the thickness of the copper deposition layer. The thickness of the copper plating layer on the surface of the plugging resin after electroplating reaches the normal design level, meets the standards of electrical conduction and component mounting, and improves the process yield and product quality. However, the use steps are cumbersome and the process is complicated. Summary of the invention

[0004] In order to develop a plugging resin that is easy to plug, has good sag properties, and is easy to clean the board surface resin, the first aspect of the present invention provides a PCB board through-hole plugging resin, and the preparation raw materials include 35-100 parts of epoxy resin combination, 5-15 parts of curing agent, 1-10 parts of curing accelerator, and 0.1-5 parts of auxiliary agent in parts by weight.

[0005] As a preferred embodiment, the raw materials for preparation include 45-85 parts of epoxy resin combination, 5-12 parts of curing agent, 1-5 parts of curing accelerator, and 0.5-2.5 parts of auxiliary agent.

[0006] As a preferred embodiment, the raw materials for preparation further include 30-60 parts by weight of inorganic filler, and the particle size of the inorganic filler is less than 15 μm.

[0007] As a preferred embodiment, the epoxy resin combination includes at least two epoxy resins, and the viscosity of the epoxy resin at 25° C. is less than 12000 mPa·s.

[0008] Preferably, the epoxy resin combination comprises at least two epoxy resins, and the viscosity of the epoxy resin at 25° C. is less than 6000 mPa·s.

[0009] As a preferred embodiment, the epoxy equivalent of the epoxy resin is 100-190 g / eq.

[0010] As a preferred embodiment, the epoxy equivalent of the epoxy resin is 100-176 g / eq.

[0011] As a preferred embodiment, the epoxy resin is selected from at least one of bismaleimide-modified epoxy resin, novolac epoxy resin, dicyclopentadiene epoxy resin, bisphenol A epoxy resin, cyanate-modified epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, o-cresol novolac epoxy resin, biphenyl phenol type epoxy resin, polyether modified epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol A novolac epoxy resin, alicyclic epoxy resin, glycidyl methacrylate, triglycidyl isocyanurate, diglycidyl phthalate, tetraglycidyl diaminodiphenylmethane, and aminophenol trifunctional epoxy resin.

[0012] As a preferred embodiment, the epoxy resin combination includes at least two of bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, and aminophenol trifunctional epoxy resin.

[0013] As a preferred embodiment, the epoxy resin combination includes bisphenol A epoxy resin, bisphenol F epoxy resin, and aminophenol trifunctional epoxy resin.

[0014] As a preferred embodiment, the bisphenol A epoxy resin has a viscosity of 6000-12000 mPa·s at 25° C. and an epoxy equivalent of 172-176 g / eq.

[0015] As a preferred embodiment, the viscosity of the bisphenol A epoxy resin at 25° C. is 7000-10000 mPa·s.

[0016] As a preferred embodiment, the bisphenol F epoxy resin has a viscosity of 2000-5000 mPa·s at 25° C. and an epoxy equivalent of 162-172 g / eq.

[0017] As a preferred embodiment, the viscosity of the bisphenol F epoxy resin at 25° C. is 2500-4500 mPa·s.

[0018] As a preferred embodiment, the aminophenol trifunctional epoxy resin has a viscosity of 500-5000 mPa·s at 25° C. and an epoxy equivalent of 100-111 g / eq.

[0019] As a preferred embodiment, the aminophenol trifunctional epoxy resin has a viscosity of 1500-5000 mPa·s at 25°C.

[0020] As a preferred embodiment, the weight ratio of the bisphenol A epoxy resin, bisphenol F epoxy resin, and aminophenol trifunctional epoxy resin is (30-45): (5-15): (10-25).

[0021] As a preferred embodiment, the weight ratio of the bisphenol A epoxy resin, the bisphenol F epoxy resin, and the aminophenol trifunctional epoxy resin is 30:5:10.

[0022] During the experiment, the inventors found that a plugging resin that is easy to plug and not prone to sagging can be prepared by using a combination of bisphenol A epoxy resin, bisphenol F epoxy resin, and trifunctional epoxy resin. The possible reasons are speculated to be: the trifunctional epoxy resin has high reaction activity, and the combination of three low-viscosity epoxy resins does not change the viscosity by more than 15% during use, making it easy to enter the hole during plugging, and not prone to sagging after plugging, which increases the difficulty of subsequent polishing. The inventors further found that bisphenol A epoxy resin, bisphenol F epoxy resin, and trifunctional epoxy resin are used in a weight ratio of 30:5:10, and are used with a curing agent and a curing agent accelerator, which extends the applicable period of the plugging resin, and the viscosity changes little during the applicable period, so that sufficient plugging operations can be performed, reducing the difficulty of operation.

[0023] As a preferred embodiment, the curing agent is selected from at least one of dicyandiamide curing agent, dicyandiamide derivative curing agent, aromatic diamine curing agent, acid anhydride curing agent, linear phenolic resin curing agent, amino resin curing agent, and organic hydrazide curing agent.

[0024] As a preferred embodiment, the curing agent is selected from at least one of a dicyandiamide curing agent and a dicyandiamide derivative curing agent.

[0025] As a preferred embodiment, the curing accelerator is selected from at least one of an imidazole accelerator and a tertiary amine curing agent.

[0026] As a preferred embodiment, the inorganic filler is selected from at least one of modified calcium carbonate, talc, titanium dioxide, silica powder, mica powder and alumina.

[0027] As a preferred embodiment, the inorganic filler is selected from at least one of modified calcium carbonate, silicon powder, talc, and titanium dioxide.

[0028] As a preferred embodiment, the inorganic filler is a combination of modified calcium carbonate and silicon powder.

[0029] As a preferred embodiment, the weight ratio of the modified calcium carbonate to the silicon powder is (30-40):(10-20). Preferably, the weight ratio of the modified calcium carbonate to the silicon powder is 35:16.

[0030] As a preferred embodiment, the auxiliary agent includes but is not limited to a defoaming agent, a thixotropic agent, and a dispersant.

[0031] As a preferred embodiment, in parts by weight, the defoaming agent is 0.1-0.5 part, the thixotropic agent is 0.5-1 part, and the dispersant is 0.1-1 part.

[0032] A second aspect of the present invention provides a method for preparing a through-hole plugging resin for a PCB board, comprising the following steps:

[0033] S1. The epoxy resin, curing agent, curing accelerator and auxiliary agent are dispersed and mixed evenly for 1-2 hours using a high-speed disperser to obtain a base material;

[0034] S2: Add inorganic filler to the base material, mix evenly with a high-speed disperser, and then grind on a grinder for 1-2 hours to control the fineness to less than 15μm to obtain a slurry;

[0035] S3: vacuum-stir the slurry for 1-3 hours, and then vacuum-degasify to obtain a plugging resin.

[0036] The inventors further discovered that adding silicon powder less than 10 μm to the plugging resin and adjusting the fineness of the slurry to less than 15 μm can improve the polishability of the plugging resin. On a small-sized PCB board, the spacing between through holes is close, and the excess part after plugging is not easy to polish. The use of small-particle silicon powder is easy to polish, and the hardness of the plugging part is high, but the excess part is easy to polish away. During the polishing process, the powder will not be polished onto the powder, and it is easier to polish flat.

[0037] The third aspect of the present invention provides an application of a through-hole plugging resin for a PCB board, which is applied in a screen printing machine plugging or vacuum plugging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a slice diagram of the plugging resin of Example 6 after plugging holes on a vacuum plugging machine, magnified 50 times;

[0039] Figure 2This is a slice diagram of the plugging resin of Example 6 after plugging holes on a vacuum plugging machine, magnified 100 times.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The PCB through-hole plugging resin of the present invention adopts a combination of bisphenol A epoxy resin, bisphenol F epoxy resin, and trifunctional epoxy resin. The prepared plugging resin is easy to plug holes and not easy to sag, and has excellent plugging performance.

[0042] (2) The PCB through-hole plugging resin of the present invention, bisphenol A epoxy resin, bisphenol F epoxy resin, and trifunctional epoxy resin are used in a weight ratio of 30:5:10, and are matched with a curing agent and a curing agent accelerator, which prolongs the applicable period of the plugging resin, and the viscosity changes little during the applicable period, thereby reducing the difficulty of the plugging operation.

[0043] (3) The PCB through-hole plugging resin of the present invention has silicon powder less than 10 μm added to the plugging resin, and the fineness of the slurry is adjusted to be less than 15 μm, which can improve the polishing property of the plugging resin. After curing, the plugging resin is heat-resistant, chemical-resistant, and easy to polish.

[0044] (4) The PCB through-hole plugging resin of the present invention is a thermosetting resin composition used for permanent plugging of through-holes in printed circuit boards. It has the properties of low viscosity, easy plugging, good anti-sagging property, and high glass transition temperature. It can not only meet the needs of existing vacuum plugging machines, but also meet the requirements for efficient and cost-effective plugging in complex printed circuit boards.

[0045] (5) The PCB through-hole plugging resin of the present invention has a simple preparation process, is easy to operate, has a wide range of raw materials, and can be mass-produced in general equipment. DETAILED DESCRIPTION

[0046] Example 1

[0047] A PCB through-hole plugging resin is prepared from raw materials including, by weight, 40 parts of an epoxy resin combination, 10 parts of a curing agent, 2 parts of a curing accelerator, 1 part of an auxiliary agent, and 47 parts of an inorganic filler.

[0048] The epoxy resin combination comprises bisphenol A epoxy resin, bisphenol F epoxy resin and phenolic modified epoxy resin in a weight ratio of 20:5:15.

[0049] The bisphenol A epoxy resin has a viscosity of 7000-10000 mPa·s at 25°C and an epoxy equivalent of 172-176 g / eq, and is purchased from Olin Epoxy, model DER332; the bisphenol F epoxy resin has a viscosity of 2000-5000 mPa·s at 25°C and an epoxy equivalent of 162-172 g / eq, and is purchased from Olin Epoxy, model DER354. The phenolic modified epoxy resin is purchased from Nan Ya Plastics, model 8240.

[0050] The curing agent is a dicyandiamide curing agent purchased from Huntsman, model OMICURE DDA5 dicyandiamide.

[0051] The curing accelerator is 2-ethyl-4-methylimidazole.

[0052] The inorganic filler is a combination of modified calcium carbonate and talcum powder, with a weight ratio of 32:15; the modified calcium carbonate is purchased from Guangxi Hezhou Kelong Powder Co., Ltd., model CC968.

[0053] The auxiliary agent comprises a defoamer, a thixotropic agent and a dispersant, and the weight ratio thereof is 0.1:0.8:0.1.

[0054] The defoamer was purchased from ELEMENTIS, model Defom 6800; the thixotropic agent was purchased from Evonik Industries, model 200; the dispersant was purchased from ELEMENTIS, model FX9200.

[0055] A method for preparing a through-hole plugging resin for a PCB board comprises the following steps:

[0056] S1: The epoxy resin, curing agent, curing accelerator and auxiliary agent are dispersed and mixed evenly for 1.5 hours using a high-speed disperser to obtain a base material;

[0057] S2: Add inorganic filler to the base material, mix evenly with a high-speed disperser, and then grind on a grinder for 2 hours to control the fineness to less than 15μm to obtain a slurry;

[0058] S3: The slurry is stirred in vacuum for 2 hours, and then vacuum degassed to obtain a plugging resin.

[0059] Example 2

[0060] A PCB through-hole plugging resin, the specific implementation manner is the same as that of Example 1, except that the epoxy resin combination includes bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic modified epoxy resin, and the weight ratio is 20:7:13.

[0061] The inorganic filler is a combination of modified calcium carbonate and talcum powder, with a weight ratio of 37:10.

[0062] Example 3

[0063] A PCB through-hole plugging resin, the specific implementation manner is the same as that of Example 1, except that the epoxy resin combination includes bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic modified epoxy resin, and the weight ratio is 20:10:10.

[0064] The inorganic filler is a combination of modified calcium carbonate and talcum powder, with a weight ratio of 30:17.

[0065] Example 4

[0066] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 1, except that the preparation raw materials include 45 parts of epoxy resin combination, 8 parts of curing agent, 2 parts of curing accelerator, 1 part of auxiliary agent, and 47 parts of inorganic filler.

[0067] The epoxy resin combination comprises bisphenol A epoxy resin, bisphenol F epoxy resin and aminophenol trifunctional epoxy resin in a weight ratio of 30:3:12.

[0068] The aminophenol trifunctional epoxy resin has a viscosity of 1500-5000 mPa·s at 25° C. and an epoxy equivalent of 100-111 g / eq. It is purchased from Tiantai Chemical, model TT300.

[0069] The inorganic filler is a combination of modified calcium carbonate and silicon powder, with a weight ratio of 30:17.

[0070] The silicon micropowder was purchased from Shenzhen Haiyang Powder Co., Ltd., model HY-G12.

[0071] Example 5

[0072] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 4, except that the epoxy resin combination includes bisphenol A epoxy resin, bisphenol F epoxy resin, and aminophenol trifunctional epoxy resin, and the weight ratio is 30:7:8.

[0073] Example 6

[0074] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 4, except that the epoxy resin combination includes bisphenol A epoxy resin, bisphenol F epoxy resin, and aminophenol trifunctional epoxy resin, and the weight ratio is 30:5:10.

[0075] The curing accelerator was purchased from Ajinomoto of Japan, model PN23J.

[0076] Example 7

[0077] A PCB board through-hole plugging resin, the specific implementation method is the same as Example 4, except that the preparation raw materials include 43 parts of epoxy resin combination, 9 parts of curing agent, 2 parts of curing accelerator, 1 part of auxiliary agent, and 45 parts of inorganic filler.

[0078] The epoxy resin combination comprises bisphenol A epoxy resin, bisphenol F epoxy resin and aminophenol trifunctional epoxy resin in a weight ratio of 28:5:10.

[0079] The inorganic filler is a combination of modified calcium carbonate and silicon powder, with a weight ratio of 25:20.

[0080] Example 8

[0081] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 1, except that the preparation raw materials include 50 parts of epoxy resin combination, 10 parts of curing agent, 2 parts of curing accelerator, 1 part of auxiliary agent, and 37 parts of inorganic filler.

[0082] The epoxy resin combination comprises bisphenol A epoxy resin, bisphenol F epoxy resin and aminophenol trifunctional epoxy resin in a weight ratio of 35:7:8.

[0083] The bisphenol A epoxy resin was purchased from Changchun Chemical Industry, model BE186;

[0084] The bisphenol F epoxy resin was purchased from Changchun Chemical Industry, model BFE170;

[0085] The aminophenol trifunctional epoxy resin was purchased from Tiantai Chemical, model TT300.

[0086] The inorganic filler is a combination of modified calcium carbonate and talcum powder, with a weight ratio of 25:1;

[0087] The auxiliary agent includes a defoamer, a thixotropic agent and a dispersant, and the weight ratio is 0.2:0.7:0.1.

[0088] Example 9

[0089] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 1, except that the preparation raw materials include 50 parts of epoxy resin combination, 8 parts of curing agent, 2 parts of curing accelerator, 1 part of auxiliary agent, and 40 parts of inorganic filler.

[0090] The epoxy resin combination comprises bisphenol A epoxy resin, bisphenol F epoxy resin and aminophenol trifunctional epoxy resin, with a weight ratio of 35:10:5.

[0091] The inorganic filler is a combination of modified calcium carbonate and talcum powder, with a weight ratio of 28:12;

[0092] The auxiliary agent comprises a defoamer, a thixotropic agent and a dispersant, and the weight ratio thereof is 0.2:0.7:0.1.

[0093] Comparative Example 1

[0094] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 1, except that, in parts by weight, the preparation raw materials include 50 parts of epoxy resin combination, 8 parts of curing agent, 2 parts of curing accelerator, and 40 parts of inorganic filler.

[0095] The epoxy resin combination is bisphenol A epoxy resin purchased from Olin Epoxy, model DER332.

[0096] The curing accelerator was purchased from Ajinomoto of Japan, model PN23J.

[0097] The inorganic filler is silicon micropowder purchased from Shenzhen Haiyang Powder Co., Ltd., model HY-G12.

[0098] Comparative Example 2

[0099] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 1, except that, in parts by weight, the preparation raw materials include 45 parts of epoxy resin combination, 8 parts of curing agent, and 47 parts of inorganic filler.

[0100] The epoxy resin combination is bisphenol F epoxy resin purchased from Changchun Chemical Industry, model BFE170;

[0101] The curing agent is 2-ethyl-4-methylimidazole.

[0102] The inorganic filler is modified calcium carbonate purchased from Guangxi Hezhou Kelong Powder Co., Ltd., model CC968.

[0103] Comparative Example 3

[0104] A PCB through-hole plugging resin, the specific implementation method is the same as that of Example 1, except that, in parts by weight, the preparation raw materials include 55 parts of epoxy resin combination, 8 parts of curing agent, and 37 parts of inorganic filler.

[0105] The epoxy resin combination is aminophenol trifunctional epoxy resin purchased from Tiantai Chemical, model TT300.

[0106] The curing agent is an aromatic diamine curing agent purchased from Jiangsu Sanmu Group, model SM113.

[0107] The inorganic filler is modified calcium carbonate purchased from Guangxi Hezhou Kelong Powder Co., Ltd., model RP5.

[0108] Performance Testing

[0109] 1. Viscosity: Use rotational viscometer VT06 to test the viscosity.

[0110] 2. Glass transition temperature: Refer to IPC-TM650 2.4.24 standard to test the glass transition temperature.

[0111] 3. Anti-sagging performance: Refer to GB / T 9264-2012, use vertical baking, bake at 100℃ for 30min, bake at 150℃ for 60min. Test the anti-sagging performance.

[0112] 4. Grinding property: The grinding property level is determined by the consumables required for grinding. Excellent: 1 set of 600 mesh ceramic brushes + 1-2 sets of 600 mesh non-woven fabrics; Good: 2 sets of 600 mesh ceramic brushes + 2-3 sets of 600 mesh non-woven fabrics; Average: 3-4 sets of 600 mesh ceramic brushes + 3-4 sets of 600 mesh non-woven fabrics; Poor: 4 sets of 600 mesh ceramic brushes + 4 sets of 600 mesh non-woven fabrics are not ground cleanly.

[0113] 5. Applicable period: The time when the viscosity change is less than 15% is the applicable period. Viscosity change = (current viscosity - initial viscosity) / initial viscosity × 100%

[0114] The test results are shown in Table 1.

[0115] Table 1

[0116]

Claims

1. A PCB board through-hole plugging resin, characterized in that: In parts by weight, the raw materials include 35-100 parts of epoxy resin combination, 5-15 parts of curing agent, 1-10 parts of curing accelerator, and 0.1-5 parts of auxiliary agent.

2. The PCB through-hole plugging resin according to claim 1, characterized in that: The raw materials for preparation also include 30-60 parts by weight of inorganic filler, and the particle size of the inorganic filler is less than 15 μm.

3. The PCB through-hole plugging resin according to claim 1, characterized in that: The epoxy resin combination comprises at least two epoxy resins, and the viscosity of the epoxy resin at 25° C. is less than 12000 mPa·s.

4. The PCB through-hole plugging resin according to claim 3, characterized in that: The epoxy equivalent of the epoxy resin is 100-190 g / eq.

5. The PCB through-hole plugging resin according to claim 3, characterized in that: The epoxy resin is selected from at least one of bismaleimide-modified epoxy resin, novolac epoxy resin, dicyclopentadiene epoxy resin, bisphenol A epoxy resin, cyanate-modified epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, o-cresol novolac epoxy resin, biphenyl phenol type epoxy resin, polyether modified epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol A novolac epoxy resin, alicyclic epoxy resin, glycidyl methacrylate, triglycidyl isocyanurate, diglycidyl phthalate, tetraglycidyl diaminodiphenylmethane, and aminophenol-based trifunctional epoxy resin.

6. The PCB through-hole plugging resin according to claim 3, characterized in that: The epoxy resin combination includes at least two of bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, and aminophenol trifunctional epoxy resin.

7. The PCB through-hole plugging resin according to claim 1, characterized in that: The curing agent is selected from at least one of dicyandiamide curing agents, dicyandiamide derivative curing agents, aromatic diamine curing agents, acid anhydride curing agents, linear phenolic resin curing agents, amino resin curing agents, and organic hydrazide curing agents.

8. The PCB through-hole plugging resin according to claim 2, characterized in that: The inorganic filler is selected from at least one of modified calcium carbonate, talc, titanium dioxide, silica powder, mica powder and alumina.

9. A method for preparing a through-hole plugging resin for a PCB board according to any one of claims 2 to 8, characterized in that: The following steps are involved: S1. The epoxy resin, curing agent, curing accelerator and auxiliary agent are dispersed and mixed evenly for 1-2 hours using a high-speed disperser to obtain a base material; S2: Add inorganic filler to the base material, mix evenly with a high-speed disperser, and then grind on a grinder for 1-2 hours to control the fineness to less than 15μm to obtain a slurry; S3 vacuum-stirs and degasses the slurry for 1-3 hours to obtain a plugging resin.

10. An application of the through-hole plugging resin of a PCB board according to any one of claims 2 to 8, characterized in that: Applicable to screen printing machine plugging or vacuum plugging process.

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