Synthesis of Organosilicon-Modified Phenolic Resin:

To synthesize phenolic resin modified with
octamethyltetrasiloxane D4, follow the steps below:

Start by melting phenol at a temperature of 40-45°C and adding NaOH aqueous solution.

After 1 minute of reaction, introduce the first formaldehyde, which should constitute 80% of the total input.

Maintain the temperature between 80 and 85°C and allow the reaction to proceed for 1 hour.

Add methanol in one dose, equivalent to 20% of the initial feed amount.

The reaction temperature for the second dose of formaldehyde should be controlled between 70 and 75°C.
Finally, raise the temperature and maintain it between 80 and 85°C to complete the synthesis reaction, resulting in a brownish-red product.

Synthesis of Organosilicon-Modified Phenolic Resin:

Add a certain amount of distilled water to a four-necked bottle equipped with a stirring mechanism, condensing tube, thermometer, and drip tube.

Heat the mixture to a specific temperature.

Add a certain amount of Sodium Dodecyl Sulfonate (SOS) and ensure it completely dissolves.

Introduce approximately 30% phenolic resin and 50% D4 lotion, stirring the mixture for 30 minutes.

Adjust the pH value of the mixture to fall between 6 and 7.
Increase the temperature to 90°C and add 20% initiator potassium persulfate at 60-70°C.

Allow the reaction to proceed at this temperature for 1 hour.
Gradually add the remaining phenolic resin, octamethyltetrasiloxane (D4) lotion, and initiator by dropwise addition.

After completing the addition, include 1-2 mL of initiator.
Continue the reaction and then discharge the mixture after it has cooled.

Preparation Method for Electronic Device Packaging Material:

To prepare the electronic device packaging material, follow the steps below:

Take 100 parts of linear phenolic resin and react it with butanol and a catalyst to obtain a modified silicon oxide phenolic resin with a modification rate of 99%.
Take out 35 parts of the obtained product and mix it with 15 parts of linear phenolic resin.

Introduce 90 parts of linear phenolic epoxy resin and 10 parts of Australian phenolic epoxy resin.
Add 430 parts of quartz powder, 25 parts of titanium dioxide, 25 parts of PPh3, 3 parts of carbon black, and 3 parts of Brazilian palm wax to the mixture as semiconductor transfer molding materials.

Thoroughly mix the components to obtain packaging materials with excellent molding processability.

Cure the products at 75°C for 8 hours using a mold temperature of 175°C and a residence time of 1 minute.
The resulting transistor shell should withstand 500 cycles of cold and hot shock between -65°C and 150°C without cracking. Test 20 samples to ensure their integrity.
Organosilicon Modified Cashew Phenolic Coating:

Cashew phenolic, the main component of natural cashew shell liquid (CNSL), bears structural similarities to urushiol, the main component of lacquer. Cashew phenolic polymer coating (CF) prepared from cashew phenolic and methylbenzene exhibits excellent physical and chemical properties similar to raw lacquer, with the added advantage of lower cost. However, the presence of phenolic -OH groups in cashew phenolic polymer molecules makes the coating prone to oxidation and renders it unsuitable for use as an anti-corrosion coating with poor alkaline resistance.

To overcome this limitation and prepare high-performance anti-corrosion coatings from natural cashew nut shell liquid, CF is easily reacted with small organic silicon molecules. CF is modified with dimethyl dichlorosilane (OMS) to create an organic silicon modified cashew nut phenolic polymer (CF-S).

The following steps outline the process:

Take five portions of CF xylene solution and place them into a three-necked flask equipped with a stirrer, a drip funnel, and a catheter.

Gradually add three portions of measured OMS dropwise while stirring.

Allow the solution to react at room temperature for 25 minutes.

Adjust the solid content of the product to approximately 55% to obtain CF-Si.

Absorb the HCI gas emitted during the reaction process using a NaOH solution.

The modification of cashew phenolic polymer coating with OMS results in an organic silicon modified cashew phenolic polymer coating (CF-Si). This modification reduces the concentration of phenolic -OH groups in CF-Si molecules, increases the crosslinking density and significantly improves the performance of the CF-Si coating. The CF-Si coating demonstrates superior physical and mechanical properties such as hardness, glossiness, and impact resistance compared to CF (refer to Table 3-28). CF-Si also exhibits higher thermal stability than CF (see Figure 3-11). After 1400 hours of UV irradiation, CF-Si experiences only a 27% loss rate, whereas CF reaches 58%, indicating improved UV resistance (see Figure 3-12). Additionally, CF-Si coating film shows significantly enhanced resistance to chemical medium corrosion, particularly alkali resistance, surpassing the performance of CF in alkaline environments.

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