Modified silicone oil emulsion release agent and method for preparing the same

Abstract

This invention provides a modified silicone oil-based emulsion mold release agent and its preparation method. The modified silicone oil-based emulsion mold release agent is prepared from the following raw materials: long-chain alkyl-modified silicone oil, dimethyl silicone oil, emulsifier, catalyst, and precipitated silica; the mass ratio of long-chain alkyl-modified silicone oil, dimethyl silicone oil, emulsifier, and precipitated silica is (10-20):(40-50):(6-15):(1-5); the HLB value of the emulsifier is 7-10; the amount of catalyst is 1%-6% of the amount of precipitated silica; the preparation method of the long-chain alkyl-modified silicone oil includes the following steps: chloroplatinic acid and end-side hydrogen-containing silicone oil are mixed and activated, octene is added, and the mixture is reacted at 85-110℃ for 4-8 hours to remove unreacted octene, thus obtaining the final product. During use, the mold release agent provided by this invention forms a protective layer on the surface of the mold through a cross-linking reaction, which can improve the mold release effect, high-temperature resistance, and durability.

Description

Technical Field

[0001] This invention relates to the field of mold release agent technology, and more specifically, to a modified silicone oil emulsion mold release agent and its preparation method. Background Technology

[0002] The main function of mold release agents is to prevent or reduce mechanical damage to molded products during demolding. Water-based mold release agents combine the lubrication and release properties of traditional mold release agents with environmentally friendly characteristics. Water is the main component of water-based mold release agents, serving as a carrier for their effective ingredients. Generally, the content of ion-exchanged water or drinking water is above 95%. However, water-based mold release agents have poor heat resistance. Silicone oil, with its low surface tension, good heat resistance, and low solubility parameter, is an ideal mold release agent material.

[0003] Release agents are functional substances that act as a medium between the mold and the finished product. Currently, release agents used in the market have poor release effects at high temperatures, affecting the surface finish and integrity of the castings, thus reducing the surface quality of the castings. Summary of the Invention

[0004] This invention provides a modified silicone oil emulsion release agent and its preparation method, which overcomes or at least partially overcomes the problems and defects of the prior art. The release agent provided by this invention enables castings to be quickly and non-adhesively removed from the mold without any pollution, effectively improving the smoothness and integrity of castings, and effectively improving the surface quality and precision of casting products.

[0005] The modified silicone oil emulsion release agent provided by this invention is prepared from raw materials comprising the following components: long-chain alkyl-modified silicone oil, dimethyl silicone oil, emulsifier, and catalyst; the mass ratio of the long-chain alkyl-modified silicone oil, dimethyl silicone oil, and emulsifier is (10-20):(40-50):(6-15); the HLB value of the emulsifier is 7-10; and the amount of catalyst is 1wt%-6wt% of the amount of silica.

[0006] The preparation method of the long-chain alkyl modified silicone oil includes the following steps: activating chloroplatinic acid and end-side hydrogen-containing silicone oil by mixing and adding octene, reacting at 85-110℃ for 4-8 hours, and removing unreacted octene to obtain the product.

[0007] In a preferred embodiment of the present invention, in the preparation method of long-chain alkyl modified silicone oil, the molar ratio of end-side hydrogen-containing silicone oil (silicon-hydrogen bonds in end-side hydrogen-containing silicone oil) to octene (carbon-carbon double bonds in octene) is 1:(1-1.6).

[0008] In a specific embodiment of the present invention, the hydrogen content of the end-side hydrogen-containing silicone oil is preferably 0.53%-0.82%. Unless otherwise specified, "%" in the present invention refers to mass percentage.

[0009] In a preferred embodiment of the present invention, in the method for preparing long-chain alkyl-modified silicone oil, the amount of chloroplatinic acid used is 10-50 ppm of the total amount of raw materials in the reaction (the reaction for preparing long-chain alkyl-modified silicone oil) (excluding chloroplatinic acid, i.e., the total amount of chloroplatinic acid, end-side hydrogen-containing silicone oil and octene).

[0010] In a preferred embodiment of the present invention, the activation temperature in the preparation method of the long-chain alkyl modified silicone oil used in the present invention is 60-80℃, and the activation time is 1-3h.

[0011] In a preferred embodiment of the present invention, the use of an emulsifier with the specified HLB value in combination with other components to prepare a release agent is one of the core inventive points of the present invention. The present invention preferably uses two or more composite emulsifiers with different HLB values. To facilitate emulsification and improve the stability of the resulting release agent, the emulsifiers of the present invention are preferably a combination of Span-60 and Tween-60. That is, the emulsifiers of the present invention are preferably Span-60 and Tween-60. When using these two emulsifiers to prepare a composite emulsifier, the amount of Span-60 and Tween-60 only needs to satisfy the requirement that the final composite emulsifier has an HLB value of 7-10.

[0012] In a preferred embodiment of the present invention, in order to improve the reaction between the other raw materials of the present invention and the specific long-chain alkyl modified silicone oil, the catalyst in the modified silicone oil emulsion release agent of the present invention is tetramethylammonium hydroxide.

[0013] In a specific embodiment of the present invention, the raw materials in the modified silicone oil emulsion release agent provided by the present invention include water, as is known to those skilled in the art, and the amount of water added is such that the solid content of the emulsion is 20%-50%.

[0014] In a preferred embodiment of the present invention, the raw materials in the modified silicone oil emulsion release agent provided by the present invention are composed of long-chain alkyl modified silicone oil, dimethyl silicone oil, silica, emulsifier, catalyst, and water. Specifically, preferably, by weight, the modified silicone oil emulsion release agent provided by the present invention is prepared from the following raw materials: 10-20 parts of long-chain alkyl modified silicone oil, 40-50 parts of dimethyl silicone oil, 2-3 parts of silica, 6-15 parts of emulsifier, and catalyst; wherein the amount of catalyst is 1wt%-6wt% of the amount of silica, and the amount of water is such that the solid content of the emulsion is 20%-50%.

[0015] In this invention, parts by weight can be weight units known in the art such as µg, mg, g, and kg, or multiples thereof, such as 1 / 10, 1 / 100, 10 times, 100 times, etc. In this invention, the amount of each substance is determined according to the above proportions, and the total mass parts of the substances are not necessarily 100 parts by weight; they can be less than 100 parts by weight or greater than 100 parts by weight, as long as they are within the above proportions.

[0016] Another object of the present invention is to provide a method for preparing the above-mentioned modified silicone oil emulsion release agent, the method comprising the following steps:

[0017] 1) Mix silica and dimethyl silicone oil according to the ratio, react at 120-160℃ for 4-8 hours, and then cool down to 40-70℃;

[0018] 2) Add long-chain alkyl-modified silicone oil and emulsifier to the system obtained in step 1) according to the ratio, and shear and stir to obtain the final product.

[0019] In one specific embodiment of the present invention, the shearing speed in step 2) can be 6000-10000 r / min, and the shearing time is 10-30 min.

[0020] The modified silicone oil emulsion release agent provided by this invention uses octene and hydrogen-containing silicone oil as base materials, and adds a specific proportion of catalyst to promote the hydrosilylation reaction. At the same time, a specific proportion of emulsifier is added to make it have good storage stability. During use, the modified silicone oil emulsion release agent forms a release agent protective layer on the surface of the mold through a cross-linking reaction, thereby improving the release effect, high temperature resistance and durability. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] Example 1

[0023] This embodiment provides a modified silicone oil-based emulsion release agent, the preparation method of which includes the following steps:

[0024] Long-chain alkyl-modified silicone oil is prepared by the following steps: 30 ppm of chloroplatinic acid and 50 g of end-side hydrogen-containing silicone oil (Runhe Material RH-LHC-2, hydrogen content 0.77%) are mixed and activated at 70°C for one hour. Then, 51.8 g of octene is added dropwise, the temperature is raised to 100°C, and after reacting for 6 hours, the excess octene is removed by applying negative pressure to obtain long-chain alkyl-modified silicone oil.

[0025] The preparation method of the modified silicone oil emulsion release agent provided in this embodiment includes the following steps:

[0026] (1) Add 1 part hydrophobic silica and 40 parts dimethyl silicone oil to a three-necked flask, add tetramethyl ammonium hydroxide (1 wt% of hydrophobic silica), stir slowly and heat to 150°C, keep the temperature for about 5 hours, and then cool down to 70°C.

[0027] (2) Add 11 parts of long-chain alkyl modified silicone oil and 11 parts of composite emulsifier to the system obtained in step (1), stir mechanically until uniform, then slowly add deionized water to prepare an emulsion with a solid content of 40%, and then stir thoroughly for 20 minutes using a high-speed shear machine at 8000 r / min to obtain the modified silicone oil emulsion release agent of this embodiment. The HLB value of the composite emulsifier prepared using Span-60 (HLB=4.7) and Tween-60 (HLB=14.9) is 8.0.

[0028] Example 2

[0029] This embodiment provides a modified silicone oil-based emulsion release agent, the preparation method of which includes the following steps:

[0030] Long-chain alkyl-modified silicone oil is prepared by the following steps: 40 ppm of chloroplatinic acid and 50 g of end-side hydrogen-containing silicone oil (Runhe Material RH-LHC-3, hydrogen content 0.82%) are mixed and activated at 70°C for one hour. Then, 55.2 g of octene is added dropwise, the temperature is raised to 100°C, and after reacting for 6 hours, the excess octene is removed by applying negative pressure to obtain long-chain alkyl-modified silicone oil.

[0031] The preparation method of the modified silicone oil emulsion release agent provided in this embodiment includes the following steps:

[0032] (1) Add 3 parts of hydrophobic silica and 40 parts of dimethyl silicone oil to a three-necked flask, add tetramethylammonium hydroxide (2wt% of hydrophobic silica), stir slowly and heat to 150°C, keep the temperature for about 5 hours, and then cool down to 70°C.

[0033] (2) Add 11 parts of long-chain alkyl modified silicone oil and 11 parts of composite emulsifier to the system obtained in step (1), stir mechanically until uniform, then slowly add deionized water to prepare an emulsion with a solid content of 40%, and then stir thoroughly for 20 minutes using a high-speed shear machine at 8000 r / min to obtain the modified silicone oil emulsion release agent of this embodiment. The HLB value of the composite emulsifier prepared using Span-60 (HLB=4.7) and Tween-60 (HLB=14.9) is 8.0.

[0034] Example 3

[0035] This embodiment provides a modified silicone oil-based emulsion release agent, the preparation method of which includes the following steps:

[0036] Long-chain alkyl-modified silicone oil is prepared by the following steps: 50 ppm of chloroplatinic acid and 50 g of end-side hydrogen-containing silicone oil (hydrogen content of 0.75%) are mixed and activated at 70°C for one hour. Then, 50.4 g of octene is added dropwise, the temperature is raised to 100°C, and after reacting for 6 hours, the excess octene is removed by applying negative pressure to obtain long-chain alkyl-modified silicone oil.

[0037] The preparation method of the modified silicone oil emulsion release agent provided in this embodiment includes the following steps:

[0038] (1) Add 3 parts of hydrophobic silica and 40 parts of dimethyl silicone oil to a three-necked flask, add tetramethylammonium hydroxide (3wt% of hydrophobic silica), stir slowly and heat to 150°C, keep the temperature for about 5 hours, and then cool down to 70°C.

[0039] (2) Add 11 parts of long-chain alkyl modified silicone oil and 11 parts of composite emulsifier to the system obtained in step (1), stir mechanically until uniform, then slowly add deionized water to prepare an emulsion with a solid content of 30%, and then stir thoroughly for 20 minutes using a high-speed shear machine at 8000 r / min to obtain the modified silicone oil emulsion release agent of this embodiment. The HLB value of the composite emulsifier prepared using Span-60 (HLB=4.7) and Tween-60 (HLB=14.9) is 8.0.

[0040] Example 4

[0041] This embodiment provides a modified silicone oil-based emulsion release agent, the preparation method of which includes the following steps:

[0042] Long-chain alkyl-modified silicone oil is prepared by the following steps: 50 ppm of chloroplatinic acid and 50 g of end-side hydrogen-containing silicone oil (hydrogen content of 0.58%) are mixed and activated at 70°C for one hour. Then, 39.1 g of octene is added dropwise, the temperature is raised to 100°C, and after reacting for 6 hours, the excess octene is removed by applying negative pressure to obtain long-chain alkyl-modified silicone oil.

[0043] The preparation method of the modified silicone oil emulsion release agent provided in this embodiment includes the following steps:

[0044] (1) Add 3 parts of hydrophobic silica and 40 parts of dimethyl silicone oil to a three-necked flask, add tetramethylammonium hydroxide (4wt% of hydrophobic silica), stir slowly and heat to 150°C, keep the temperature for about 5 hours, and then cool down to 70°C.

[0045] (2) Add 11 parts of long-chain alkyl modified silicone oil and 11 parts of composite emulsifier to the system obtained in step (1), stir mechanically until uniform, then slowly add deionized water to prepare an emulsion with a solid content of 30%, and then stir thoroughly for 20 minutes using a high-speed shear machine at 8000 r / min to obtain the modified silicone oil emulsion release agent of this embodiment. The HLB value of the composite emulsifier prepared using Span-60 (HLB=4.7) and Tween-60 (HLB=14.9) is 8.0.

[0046] Experimental Example 1

[0047] The release agents obtained in Examples 1-4 and the purchased release agents in Comparative Examples 1-3 (wherein, Comparative Example 1 is a purchased Dego 406 release agent, Comparative Example 2 is a purchased Wacker E1006 release agent, and Comparative Example 3 is a purchased domestic Yue Dingxin PETS release agent) were coated onto the metal mold.

[0048] After grinding a 120×60mm steel plate, apply a release agent. The release agent should not be applied too thickly; it should be applied evenly and without any missed spots or drips. Bake the plate in a constant temperature oven at 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, and 300℃ for half an hour each. After removing the plate, observe the color change of the film on the surface of the steel plate and perform a thermal stability test (the appearance of blackening and carbonization indicates deterioration). The results are shown in Table 1 below.

[0049] Table 1. Thermal stability test results

[0050] ;

[0051] 2. Isolation and demolding experiments were conducted using the release agents obtained in Examples 1-4 and the release agents in Comparative Examples 1-3.

[0052] Apply release agent evenly three times (recorded as one application) to the polished and cleaned metal mold surface, with a 5-minute interval between each application, and allow to air dry at room temperature. Cut the prepreg and place it into the mold. Initially, heat to 180°C and hold for 30 minutes to allow the resin to fully flow. Then, apply pressure (approximately 0.5 MPa) and heat to the molding temperature of 190°C or 200°C, hold for 2 hours, and allow to cool naturally. Finally, demold the mold and record the number of successful demoldings.

[0053] The release agent is milky white in appearance. It is stored at room temperature, and the presence of oil-water separation is observed. The storage time is recorded.

[0054] The results are shown in Table 2 below:

[0055] Table 2 Results of the isolation and demolding experiment

[0056] ;

[0057] Finally, the method of this invention is merely a preferred embodiment and is not intended to limit the scope of protection of this invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A modified silicone oil-based emulsion release agent, characterized by, It is prepared from raw materials comprising the following components: long-chain alkyl-modified silicone oil, dimethyl silicone oil, emulsifier, catalyst, and precipitated silica; wherein the mass ratio of the long-chain alkyl-modified silicone oil, dimethyl silicone oil, emulsifier, and precipitated silica is (10-20):(40-50):(6-15):(1-5); wherein the emulsifier has an HLB value of 7-10; wherein the amount of catalyst is 1wt%-6wt% of the amount of precipitated silica; wherein the catalyst is tetramethylammonium hydroxide; and wherein the emulsifier is Span-60 and Tween-60. The preparation method of the long-chain alkyl-modified silicone oil includes the following steps: chloroplatinic acid and end-chain hydrogen-containing silicone oil are mixed and activated, octene is added, and the mixture is reacted at 85-110℃ for 4-8 hours. Unreacted octene is removed to obtain the final product. The molar ratio of silicon-hydrogen bonds in the end-chain hydrogen-containing silicone oil to carbon-carbon double bonds in the octene is 1:(1-1.6). The amount of chloroplatinic acid used is 10-50 ppm. The hydrogen content of the end-chain hydrogen-containing silicone oil is 0.53%-0.82%.

2. The modified silicone oil emulsion release agent according to claim 1, characterized by, The activation temperature is 60-80℃, and the activation time is 1-3 hours.

3. The modified silicone oil emulsion release agent according to claim 1, characterized by, The raw materials also include water, and the amount of water used is such that the solid content of the emulsion is 20%-50%.

4. The modified silicone oil emulsion release agent according to any one of claims 1 to 3, by weight, is prepared from the following raw materials: long-chain alkyl modified silicone oil, dimethyl silicone oil, silica, emulsifier, catalyst and water.

5. The method for producing a modified silicone oil emulsion release agent according to any one of claims 1 to 4, characterized in that, Includes the following steps: 1) Mix silica, dimethyl silicone oil and catalyst according to the formula, react at 120-160℃ for 4-8 hours, and then cool down to 40-70℃; 2) Add long-chain alkyl-modified silicone oil and emulsifier to the system obtained in step 1) according to the ratio, and shear and stir to obtain the final product.