Modified organic silicon resin and adhesive applying same

Abstract

According to the preparation method of the modified organic silicon resin, hydrogen-containing silicon resin, acrylate with a long-chain alkane group and glycidyl monoene are subjected to an addition reaction, and the long-chain alkane group and an epoxy group are grafted to the hydrogen-containing silicon resin; the prepared modified organic silicon resin is applied to an epoxy resin adhesive system, and the characteristics of the two resins can complement each other and have a synergistic effect, so that the compatibility of the system is improved, the heat resistance is improved, the permeation and hydrophobic capacities of a flexible copper-clad plate and a copper foil to a base material are improved, the stripping force is improved, and the probability of etching by an etching solution is reduced; therefore, the resolution and the accuracy of the electronic circuit prepared by the photoetching process are improved.

Description

Technical Field

[0001] This invention relates to the field of flexible copper clad laminate adhesives, and in particular to a modified silicone resin and an adhesive using the same. Background Technology

[0002] In the field of flexible copper-clad laminates (CCLs), epoxy resin adhesives possess numerous significant advantages, including strong adhesion, good insulation properties, and low curing shrinkage, making them a widely used type of adhesive. However, epoxy resin adhesives have two main drawbacks. First, due to their high polarity and hydrophilicity, they have a high water absorption rate. During the production and use of flexible CCLs, they may come into contact with chemicals such as etchants. This high water absorption rate reduces their resistance to etchant corrosion, affecting the performance and lifespan of the CCL. Second, the high crosslinking density of cured epoxy resin makes the material brittle, prone to cracking, and lacking in flexibility. In flexible electronics, materials need to possess good flexibility to adapt to various bending, folding, and other deformations. Currently, there are two main methods to improve the aforementioned shortcomings of epoxy resin adhesives: one is to add rubber or modify rubber, and the other is to directly modify the epoxy resin. Due to differences in chemical structure and polarity, rubber and epoxy resin have poor compatibility. In adhesive systems, rubber may be dispersed as an independent phase within the epoxy resin matrix. During curing, this can easily lead to phase separation, affecting the overall heat resistance and high-temperature mechanical properties of the adhesive. Furthermore, it may disrupt the density of the epoxy resin matrix, creating tiny pores and channels that provide pathways for water molecules to penetrate and adsorb, making it easier for water molecules to enter the adhesive and thus increasing water absorption. Direct modification of epoxy resin, on the other hand, makes it difficult to simultaneously improve multiple performance indicators. For example, modifying epoxy resin with long chains can increase its flexibility and reduce its water absorption, but this may reduce the adhesive strength and heat resistance of the adhesive, failing to meet the flexibility requirements of flexible electronics. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing modified organosilicon resin that can synergistically enhance the overall performance of epoxy resin adhesives.

[0004] The objective of this invention is achieved through the following technical solution: A method for preparing a modified organosilicon resin includes the following steps: S1 adds hydrosilicone resin, acrylate with long-chain alkane groups, and glycidyl monoene monomer to a reaction vessel and stirs until homogeneous. The stirred mixture is then dispersed in solvent A, and platinum catalyst is added and stirred until homogeneous. S2 is heated to carry out a hydrosilylation reaction; After the S3 and S2 reactions are completed, the temperature is lowered and activated carbon is added to adsorb the catalyst. The mixture is then filtered, and the filtrate is subjected to vacuum distillation to remove the solvent, yielding the modified organosilicon resin. The ratio of the sum of the molar numbers of the long-chain alkane acrylate and the glycidyl olefin monomer to the molar number of silane groups in the hydrogen-containing silicone resin is (1.2-1.5):1, and the molar ratio of the long-chain alkane acrylate and the glycidyl olefin monomer is (2-5):1.

[0005] In a preferred embodiment, the hydrogen-containing silicone resin is any one of methyl hydrogen-containing silicone resin, phenyl hydrogen-containing silicone resin, methylphenyl hydrogen-containing silicone resin, or a mixture thereof, and the active hydrogen mass fraction of the hydrogen-containing silicone resin is 0.1-1.0%.

[0006] In a preferred embodiment, the acrylate with long-chain alkane groups is any one of octadecyl methacrylate, octadecyl acrylate, isooctyl methacrylate, isooctyl acrylate, lauryl methacrylate, or a mixture thereof.

[0007] In a preferred embodiment, the glycidyl monoene monomer is any one of glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, or a mixture thereof.

[0008] In a preferred embodiment, solvent A is a mixture of toluene and methyl ethyl ketone.

[0009] In a preferred embodiment, in S2, the hydrosilylation reaction temperature is 80~100℃ and the reaction time is 3-4h.

[0010] In one preferred embodiment, in step S3, the temperature is lowered to 50-60℃ for activated carbon adsorption.

[0011] This invention involves an addition reaction of a hydrosilicone resin, an acrylate with long-chain alkane groups, and a glycidyl monoolefin to attach long-chain alkane groups and epoxy groups to the hydrosilicone resin. In a preferred embodiment, the synthesis reaction is shown in Formula I: The present invention also provides an adhesive comprising the modified organosilicon resin prepared according to any one of claims 1-6.

[0012] In a preferred embodiment, the adhesive comprises, by weight, 1.0-10.0 parts of modified silicone resin, 10.0-50.0 parts of epoxy resin, 5.0-15.0 parts of nitrile rubber, 10.0-20.0 parts of flame retardant, 0.5-3.0 parts of curing agent, 0.02-1.0 parts of imidazole curing accelerator, 0.02-0.06 parts of antioxidant, and 30.0-60.0 parts of solvent B.

[0013] In the above adhesive components, the epoxy resin is any one of bisphenol A type epoxy resin, phenolic type epoxy resin, dicyclopentadiene epoxy resin, biphenyl type epoxy resin, or a mixture thereof; preferably, it is a mixture of bisphenol A type epoxy resin and dicyclopentadiene epoxy resin. The nitrile rubber is hydroxyl-based nitrile rubber or carboxylated nitrile rubber or a mixture thereof; preferably, it is carboxylated nitrile rubber. The curing agent is 4,4'-diaminodiphenyl sulfone; The imidazole curing accelerator is any one of 1-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, or a mixture thereof; preferably 2-ethyl-4-methylimidazole; The flame retardant is aluminum hydroxide, aluminum diethylphosphinate, or a mixture thereof; preferably, it is a mixture of aluminum hydroxide and aluminum diethylphosphinate. The antioxidant is any one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl]phosphite, tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) or a mixture thereof; preferably a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide); Solvent B is a ketone solvent or an amide solvent. The ketone solvent is acetone, butanone, methyl isobutyl ketone, cyclohexanone, isophorone, diacetone alcohol, or a mixture thereof, preferably a mixture of acetone and butanone. The amide solvent is N,N'-dimethylformamide, N,N'-dimethylacetamide, or a mixture thereof, preferably N,N'-dimethylformamide.

[0014] Compared with the prior art, the present invention has at least the following advantages: 1. The modified organosilicon resin prepared by this invention contains epoxy groups and long-chain alkane groups. The long-chain alkane groups increase the flexibility and hydrophobicity of the molecular chain, forming soft segments inside the resin. When subjected to external forces, these soft segments can absorb and disperse stress through the rotation and slippage of the molecular chain, thereby improving the flexibility and hydrophobicity of the adhesive film cured with it. The epoxy groups further enhance the thermal stability of the resin and reduce the occurrence of reactions such as thermal decomposition and volatilization of the molecular chain at high temperatures, thereby improving the heat resistance of the modified organosilicon resin.

[0015] 2. The modified organosilicon resin prepared by this invention has good compatibility with epoxy resin, and its epoxy groups can participate in the cross-linking reaction, which can further improve the compatibility with the epoxy resin adhesive system and form a more uniform system. In this system, the properties of the two resins can complement and synergistically enhance each other, thereby improving heat resistance, increasing the penetration and hydrophobicity of flexible copper-clad laminate copper foil into the substrate, improving peel strength, reducing the probability of being etched by etching solution, and thus improving the resolution and accuracy of electronic circuits prepared by photolithography. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0017] Figure 1 The Fourier transform infrared absorption spectrum of the modified organosilicon resin in the embodiments of the present invention is shown below. Figure 2 The surface state diagram of the copper-clad laminate prepared with the adhesive provided in Comparative Example 6 of the present invention after etching. Figure 3 The surface state diagram of the copper-clad laminate prepared with the adhesive provided in Embodiment 3 of the present invention after etching. Detailed Implementation

[0018] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] Unless otherwise specified, all technical and scientific terms used herein have the common meaning as understood by those skilled in the art in relation to the invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0021] For the sake of brevity, not all possible combinations of the technical features in each embodiment or implementation are described herein. Therefore, as long as the combinations of these technical features do not contradict each other, the technical features in each embodiment or implementation can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] It should be noted that the hydrogen-containing silicone resin raw material used in this invention is a commercially available product, and the hydrogen content refers to the mass percentage of active hydrogen (i.e., hydrogen atoms directly bonded to silicon atoms) in the molecule.

[0023] In one or more preparation examples, the preparation steps of the modified organosilicon resin of the present invention include: S1 adds hydrosilicone resin, acrylate with long-chain alkane groups, and glycidyl monoolefin monomer to a reaction vessel in a set ratio and stirs until homogeneous. The stirred mixture is then dispersed in a mixed solvent of toluene and butanone, and platinum catalyst is added and stirred until homogeneous. S2 is heated and carried out a hydrosilylation reaction at 80℃-100℃ for 3-4 hours; After the S3 and S2 reactions are completed, the temperature is lowered to below 60℃, activated carbon is added to adsorb the catalyst, and the mixture is filtered. The filtrate is then subjected to vacuum distillation at a pressure of 10-25 mmHg to remove the mixed solvent of toluene and butanone, yielding the modified organosilicon resin.

[0024] In the following preparation examples 1-5, S1, the hydrosilicone resin, acrylate with long-chain alkane groups, and glycidyl monoene monomer were added to the reactor in the proportions in Table 1 and stirred until homogeneous. The stirred mixture was then dispersed in a toluene and butanone mixed solvent, and a platinum catalyst was added and stirred until homogeneous. S2 is heated to 80℃ and a hydrosilylation reaction is carried out for 4 hours. After the S3 and S2 reactions are completed, the temperature is lowered to 55℃ and activated carbon is added to adsorb the catalyst. The mixture is then filtered, and the filtrate is subjected to vacuum distillation at 15 mmHg to remove the mixed solvent of toluene and butanone, yielding the modified organosilicon resin.

[0025] Table 1. Main raw materials for preparation examples 1-5 Generally, in infrared spectra, epoxy groups typically exhibit characteristic absorption peaks at approximately 820-850 cm⁻¹ and 910-915 cm⁻¹. C-H groups in long-chain alkane groups show strong stretching vibration absorption peaks in the 2800-3000 cm⁻¹ region and bending vibration absorption peaks in the approximately 1360-1470 cm⁻¹ region. For unmodified hydrogen-containing silicone resins, Si-H bonds typically exhibit characteristic absorption peaks at approximately 2100-2200 cm⁻¹ in infrared spectra, while Si-O-Si bonds show a broad and strong absorption peak at 1000-1100 cm⁻¹. The Fourier transform infrared absorption spectra of the modified silica sol used in Examples 1-3 of this invention are shown below. Figure 1As shown, the absorption peak at approximately 2100–2200 cm⁻¹ is significantly weakened, while a distinct absorption peak is observed at 1000–1100 cm⁻¹. Combined with the hydrosilylation reaction mentioned in the preparation method, it can be inferred that the hydrogen-containing silicone resin participates in the reaction as a basic structure, the Si-H bonds effectively participate in the reaction, and the Si-O-Si structure is preserved during the reaction. Figure 1 Furthermore, distinct absorption peaks can be observed in the characteristic absorption peak regions of the aforementioned epoxy groups, long-chain alkane groups, and Si-O-Si bonds, indicating that the glycidyl monoene monomer has successfully participated in the reaction and been introduced into the structure of the organosilicon resin.

[0026] The modified organosilicon resin was prepared according to the components and proportions in Tables 2 and 3, including the following steps: the components were placed into a mixing tank in sequence, the stirring speed was controlled at 800 rpm, and then the mixture was ground in a sand mill to obtain a final fineness of ≤10 μm. The modified organosilicon resins of Examples 1-3 in Table 2 correspond to the modified organosilicon resins prepared in Examples 1-3, and the modified organosilicon resins of Comparative Examples 1-2 in Table 3 correspond to the modified organosilicon resins prepared in Examples 4-5.

[0027] Table 2. Distribution ratio of groups 1-3 in Examples Table 3. Allocation ratios of comparative examples 1-6 Perform the following operations on the adhesives in the above examples: Coating is applied to the surface of a polyimide (PI) film, and after drying and curing processes, a 30-micron-thick cured film is formed on the PI film surface. Copper foil with an ultra-low surface roughness of 18 microns is then covered on the upper and lower ends of the PI film. The copper-clad laminate is obtained by hot pressing in a vacuum press at a pressure of 5 MPa and a temperature of 150°C for 1.5 hours.

[0028] The following tests were performed on samples of the copper-clad laminate: 1) Peel test: Refer to IPC-TM-650 2.4.9-1 and use the 180° peel method at a peel rate of 50 mm / min to test the average peel force between the copper foil and the substrate.

[0029] 2) Heat resistance test: Another copper-clad laminate sample was placed at 285℃, 275℃, and 265℃ for 12 hours. The surface condition of the copper-clad laminate after the test was visually observed to determine whether it was qualified. If the copper foil of the copper-clad laminate did not peel up, there were no bubbles between the layers and on the sides, and there was no delamination, it was recorded as "✔". If the surface of the copper-clad laminate after the test showed bubbles and / or delamination, it was recorded as "✖". 3) Water absorption rate test: Refer to the test method of GB / T13557-2017. Take another sample, wipe it clean, and place it in an oven at 105~110℃ to dry for 1 hour. After taking it out, put it in a desiccator to cool to room temperature. Immediately after taking it out of the desiccator, make the first weighing record. Then put the sample into a constant temperature water bath containing distilled water. All edges should be completely immersed in the water, and prevent any contact between the samples or between the sample and the container wall. The water temperature should be maintained at (23+1)℃. After 24 hours, take the sample out of the water, wipe off the surface moisture, and immediately make the second weighing record. Calculate the water absorption rate based on the two weighing records.

[0030] 4) Corrosion resistance: Patterned lines are obtained on the surface of the copper-clad laminate using existing etching processes and etching solutions. The copper-clad laminate is tested for its resistance to etching solutions. If the copper foil of the copper-clad laminate does not lift after etching, and there are no bubbles between layers and on the sides, and no delamination, it is recorded as "✔". If bubbles and / or delamination appear on the surface of the copper-clad laminate after etching, it is recorded as "✖".

[0031] 5) Flexibility test: The bending radius is gradually reduced. Within the radius range of 0.1-1.0 mm, the sample is bent 180° around the mandrel and held for 1 minute. The structural integrity of the bend is observed under a microscope (50x). If no blistering, delamination, delamination or cracks are observed between the copper foil and the substrate at the bend, it is recorded as "✔"; otherwise, it is recorded as "✖".

[0032] Table 4 Test results for each sample Figure 2 The image shows the surface state of the copper-clad laminate prepared with the adhesive provided in Comparative Example 6 after etching. After etching, some of the copper foil peels up, indicating that the copper foil in that part has detached from the cured film. Figure 3 The image shows the surface state of the copper-clad laminate prepared with the adhesive provided in Example 3 after etching. No blistering or delamination occurred on the surface after etching, indicating that the flexible copper-clad laminate circuit prepared with the adhesive provided in Example 3 has a higher etching resistance than conventional adhesives.

[0033] As shown in Table 4, the copper-clad laminates using the adhesives of Examples 1-3 can achieve a balance of flexibility, heat resistance, moisture resistance, and water absorption. Compared with Comparative Examples 1-6, they can improve the overall performance of flexible copper-clad laminates. After a heat resistance test at 285 °C, they do not blister or delaminate, and the peel strength can reach 1.6 kgF / cm, with a water absorption rate of less than 0.3%. The modified silicone resins used in Comparative Examples 1 and 2 were prepared using the same method as in Example 1. However, the modified silicone resin used in the adhesive of Comparative Example 1 had a higher proportion of glycidyl olefin monomers, resulting in a higher crosslinking density of the resin. This restricted the movement of molecular chains and enhanced the interaction between molecular chains, thereby improving the heat resistance and corrosion resistance of the product. However, the flexibility was not as expected. The modified silicone resin used in the adhesive of Comparative Example 2 had a higher proportion of long-chain alkane acrylates during preparation. While improving the flexibility of the product, the excessively high proportion of long-chain alkane groups affected the stability of the resin at high temperatures, leading to a decrease in the heat resistance of the product.

[0034] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a modified organosilicon resin, characterized in that, Includes the following steps: S1 adds hydrosilicone resin, acrylate with long-chain alkane groups, and glycidyl monoene monomer to a reaction vessel and stirs until homogeneous. The stirred mixture is then dispersed in solvent A, and platinum catalyst is added and stirred until homogeneous. S2 is heated to carry out a hydrosilylation reaction; After the S3 and S2 reactions are completed, the temperature is lowered and activated carbon is added to adsorb the catalyst. The mixture is then filtered, and the filtrate is subjected to vacuum distillation to remove solvent A, yielding the modified organosilicon resin. The molar ratio of the long-chain alkane acrylate to the glycidyl olefin monomer is (2-5):1, and the ratio of the sum of the molar numbers of the long-chain alkane acrylate and the glycidyl olefin monomer to the molar number of silane groups in the hydrogen-containing silicone resin is (1.2-1.5):

1.

2. The preparation method according to claim 1, characterized in that, The hydrogen-containing silicone resin is any one of methyl hydrogen-containing silicone resin, phenyl hydrogen-containing silicone resin, methylphenyl hydrogen-containing silicone resin, or a mixture thereof, and the hydrogen content of the hydrogen-containing silicone resin is 0.1-1.0%.

3. The preparation method according to claim 1, characterized in that, The acrylate with long-chain alkane groups is any one of octadecyl methacrylate, octadecyl acrylate, isooctyl methacrylate, isooctyl acrylate, lauryl methacrylate, or a mixture thereof.

4. The preparation method according to claim 1, characterized in that, The glycidyl monoene monomer is any one of glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, or a mixture thereof.

5. The preparation method according to claim 1, characterized in that, Solvent A is a mixture of toluene and methyl ethyl ketone.

6. The preparation method according to claim 1, characterized in that, In S2, the hydrosilylation reaction temperature is 80~100℃ and the reaction time is 3-4h.

7. The preparation method according to claim 1, characterized in that, In S3, the temperature is lowered to 50-60℃ for activated carbon adsorption.

8. An adhesive, characterized in that, Including the modified organosilicon resin prepared according to any one of claims 1-7.

9. The adhesive according to claim 8, characterized in that, The adhesive comprises: By weight, the modified silicone resin comprises 1.0-10.0 parts, epoxy resin 10.0-50.0 parts, nitrile rubber 5.0-15.0 parts, flame retardant 10.0-20.0 parts, curing agent 0.5-3.0 parts, imidazole curing accelerator 0.02-1.0 parts, antioxidant 0.02-0.06 parts, and solvent B 30.0-60.0 parts.

10. The adhesive according to claim 9, characterized in that, The epoxy resin is a mixture of bisphenol A type epoxy resin and dicyclopentadiene epoxy resin; the nitrile rubber is carboxylated nitrile rubber; the curing agent is 4,4'-diaminodiphenyl sulfone; the imidazole curing accelerator is 2-ethyl-4-methylimidazolium; the flame retardant is a mixture of aluminum hydroxide and aluminum diethylphosphinate; the antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide); and solvent B is a ketone solvent or an amide solvent.

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