Heat-conducting organic silicon test tool cleaning agent and application thereof

Abstract

The invention provides a heat-conducting organic silicon test tool cleaning agent and application thereof. The heat-conducting organic silicon test tool cleaning agent is prepared from the following raw materials in percentage by mass: 30-60% of a diluent, 20-40% of an organic silicon degumming agent, 10-40% of a swelling agent and 1-6% of a charge neutralizer. The organic silicon degumming agent is a silicon-based end-capped polyether compound, the swelling agent is alkyl-substituted intracyclic siloxane, and the charge neutralizer is an acid ester compound. According to the cleaning agent, through combination of the diluent, the organic silicon degumming agent, the swelling agent and the charge neutralizer, heat-conducting organic silicon materials such as heat-conducting silica gel and heat-conducting silicone grease can be efficiently separated from the surface of the metal tool, and the surface of the metal tool is not damaged.

Description

Technical Field

[0001] This invention relates to a chemical cleaning agent, and more particularly to a cleaning agent for thermally conductive silicone testing fixtures. Background Technology

[0002] Thermally conductive silicone materials are typically thermally conductive silicone gels or thermally conductive silicone greases. Due to their excellent thermal conductivity, insulation, temperature resistance, and elasticity, they are widely used in high-tech fields such as new energy vehicles, consumer electronics, LED lighting, photovoltaics, energy storage, and solar thermal power generation, serving as thermal interface materials (TIMs) to achieve efficient heat dissipation and system protection.

[0003] In the development and production field, thermally conductive silicone gels and greases are frequently applied to the surfaces of metal test fixtures for various performance tests. After testing, the metal test fixtures usually need to be cleaned. The conventional cleaning method is to use a rag soaked in organic solvent to wipe away any remaining thermally conductive silicone gel or grease residue. This cleaning method has several drawbacks: 1. Relatively environmentally friendly solvents such as alcohol are difficult to use thoroughly, while solvents such as xylene, toluene, and chlorosilanes are highly toxic, environmentally unfriendly, and prone to volatility, resulting in low reusability. 2. Because thermally conductive silicone gels and greases contain a large amount of thermally conductive fillers, which are generally high-hardness materials such as alumina, wiping can easily damage the surface roughness and alter surface energy parameters of the metal test fixtures due to friction. Since these metal test fixtures are precision testing components, fixtures with unsatisfactory surface roughness and surface energy must be scrapped, resulting in significant cost waste. Third, the testing equipment is large in quantity, requiring personnel to wipe and clean each one individually, which is inefficient.

[0004] Although various cleaning agents have emerged on the market, existing formulations often contain acids / alkalis or fluorine compounds, which achieve their dissolving and cleaning effects by attacking and degrading organosilicon molecular chains. These substances are typically highly toxic and irritating, requiring strict safety precautions during use. Furthermore, while corrosion inhibitors are added, these cleaning agents still pose a risk of corrosive damage to other non-target substances such as metals, thus limiting their application.

[0005] Therefore, developing a cleaning agent suitable for cleaning thermally conductive silicone testing fixtures and effectively solving the aforementioned pain points is a key challenge that the industry needs to consider. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a thermally conductive silicone testing fixture cleaning agent and its application. This thermally conductive silicone testing fixture cleaning agent is environmentally friendly and can efficiently separate thermally conductive silicone materials such as thermally conductive silicone gel and grease from the surface of metal fixtures without damaging the surface. It also has low volatility, allowing for repeated use.

[0007] To achieve the above objectives, the first aspect of the present invention provides a cleaning agent for thermally conductive silicone testing fixtures. The raw materials for preparation include, by mass percentage, 30-60% diluent, 20-40% silicone degumming agent, 10-40% swelling agent, and 1-6% charge neutralizing agent. The silicone degumming agent is a silicone-based end-capped polyether compound, the swelling agent is an alkyl-substituted intracyclic siloxane, and the charge neutralizing agent is an acid ester compound.

[0008] The cleaning agent of this invention is prepared from raw materials including a diluent, an organosilicon degumming agent, a swelling agent, and a charge neutralizing agent. The combination of these four substances efficiently separates thermally conductive organosilicon materials such as thermally conductive silicone gel and thermally conductive silicone grease from the surface of metal tooling without damaging the surface of the metal tooling. Its specific mechanism of action is as follows.

[0009] (1) The diluent is beneficial to the compatibility of organosilicon degumming agent, swelling agent and charge neutralizing agent.

[0010] (2) Organosilicon degumming agents are silicon-based end-capped polyether compounds. Their main chain is composed of weakly polar / nearly nonpolar covalent carbon-hydrogen and carbon-carbon bonds, and the ends are composed of strongly polar oxygen and silicon-oxygen bonds. In contrast, the main chain of organosilicon polymers in thermally conductive silicone gels / thermally conductive silicone greases is composed of silicon-oxygen bonds. A large number of carbon-based groups are enriched around the main chain. Due to the large electronegativity difference (approximately 1.54), silicon-oxygen bonds are strongly polar covalent bonds. The hierarchical structure has 50% ionicity. The side chain carbon-hydrogen bonds have a small electronegativity difference (approximately 0.35), and are weakly polar / nearly nonpolar covalent bonds. Due to the polar compatibility between the silicone degumming agent and the silicone polymers in the thermally conductive silicone gel / grease, the weakly polar / nearly nonpolar C-H and C-C bonds of the silicone-terminated polyether compound backbone first contact with the similarly weakly polar / nearly nonpolar C-H bonds surrounding the silicone polymer backbone in the thermally conductive silicone gel / grease, thus disrupting the bonds between the silicone polymer chains. The large electronegativity difference between the numerous hydrogen atoms on the silicone-terminated polyether compound backbone and the numerous oxygen atoms on the silicone backbone also allows for bonding. Furthermore, the silicone polymer chains are completely surrounded (solventized) by the silicone-terminated polyether compound molecules, thus separating from the three-dimensional network structure and becoming individual molecular chains encapsulated by silicone-terminated polyether compound molecules. These molecular chains disperse in the cleaning agent, achieving the degumming effect. The silicone degumming agent has low volatility, allowing for repeated use.

[0011] (3) The swelling agent is an alkyl-substituted intracyclic siloxane. This type of compound is environmentally friendly and harmless to the human body. More importantly, it has the same chemical group structure as the organosilicon polymer in thermally conductive silicone gel / thermal grease. When it comes into contact with thermally conductive silicone gel / thermal grease, it will first penetrate into the gaps in the molecular network structure of the organosilicon polymer in the thermally conductive silicone gel / thermal grease, weakening and destroying the interaction forces between the molecular chains of the organosilicon polymer in the thermally conductive silicone gel / thermal grease, thereby "opening up" the polymer chains. As a large number of alkyl-substituted intracyclic siloxanes enter the polymer network, the gaps between the polymer chains are widened, and the volume of the entire silicon material will expand significantly, soften, and lose its original mechanical strength, thus achieving a swelling effect, making it easy to separate from the metal surface.

[0012] (4) The main components of thermally conductive silicone gel / thermally conductive grease typically include organosilicon polymers, thermally conductive powders, powder surface treatment agents, and some other carbon-carbon structured polymers. The powder surface treatment agent is attached to the surface of the thermally conductive powder at one end due to electroadhesion or van der Waals forces, and the other end is wound or otherwise attached to the organosilicon polymer. The charge neutralizing agent of this invention is an acid ester compound, which can effectively weaken the force of the powder surface treatment agent, accelerate the separation of the organosilicon polymer from the thermally conductive powder, and disperse it into the cleaning agent, thereby achieving a cleaning effect.

[0013] As one technical solution of the present invention, it comprises, by mass percentage, 35-65% diluent, 20-30% silicone degumming agent, 10-30% swelling agent and 1-5% charge neutralizing agent.

[0014] As one technical solution of the present invention, it comprises, by mass percentage, 40-55% diluent, 25-30% silicone degumming agent, 15-25% swelling agent and 2-5% charge neutralizing agent.

[0015] As a technical solution of the present invention, the structural formula of the silicon-based end-capped polyether compound is shown in Formula I or Formula II, where n is a natural number from 3 to 20, m is a natural number from 6 to 16, and n1 is a natural number from 8 to 25.

[0016]

[0017] Formula I Formula II As one technical solution of the present invention, the diluent is white mineral oil.

[0018] As a technical solution of the present invention, the diluent is selected from at least one of 3# white mineral oil, 5# white mineral oil, 7# white mineral oil, 10# white mineral oil and 15# white mineral oil.

[0019] As a technical solution of the present invention, the swelling agent is selected from at least one of octamethylcyclotetrasiloxane, dodecylcyclohexasiloxane, tetradecylcycloheptasiloxane, hexadecylcyclooctasiloxane, octadecylcyclononasiloxane and icosylcyclodecasiloxane.

[0020] As a technical solution of the present invention, the charge neutralizing agent is selected from at least one of polyethylene glycol oleate, polyethylene glycol laurate, sorbitan oleate, sorbitan stearate and ethoxylated fatty acid esters. The second aspect of the present invention provides the application of a thermally conductive silicone test fixture cleaning agent on a thermally conductive silicone test fixture, wherein the silicone test fixture is immersed in the thermally conductive silicone test fixture cleaning agent and ultrasonically cleaned.

[0021] As a technical solution of the present invention, the thermally conductive silicone testing fixture is a metal testing fixture with a surface coated with a silicone composition, wherein the silicone composition includes a silicone polymer, a thermally conductive powder, and a powder surface treatment agent. Detailed Implementation

[0022] The cleaning agent of this invention is used for the separation and cleaning of silicone compositions on thermally conductive silicone testing fixtures. Thermally conductive silicone testing fixtures typically refer to metal testing fixtures with a surface coated with a silicone composition. The silicone composition can be a thermally conductive silicone gel or thermally conductive silicone grease, comprising silicone polymers, thermally conductive powders, and powder surface treatment agents. Silicone polymers typically refer to products of hydrosilylation or silanol condensation reactions. Thermally conductive powders are typically thermally conductive fillers such as alumina, boron nitride, and zinc oxide. Powder surface treatment agents are typically used for surface treatment of thermally conductive powders to facilitate dispersion and compatibility of the powders within the silicone polymer; these are typically silane coupling agents or silicone additives. When using the cleaning agent of this invention to separate and clean the silicone composition on thermally conductive silicone testing fixtures, the silicone testing fixtures can be immersed in the cleaning agent and ultrasonically cleaned. The ultrasonic cleaning frequency is 20~120kHz, the temperature is 15~35℃, and the time is 0.5~3.0h.

[0023] The cleaning agent for the thermally conductive silicone testing fixture of the present invention comprises, by mass percentage, 30-60% diluent, 20-40% silicone degumming agent, 10-40% swelling agent, and 1-6% charge neutralizing agent. Further, the preparation materials comprise 35-65% diluent, 20-30% silicone degumming agent, 10-30% swelling agent, and 1-5% charge neutralizing agent. Even further, the preparation materials comprise 40-55% diluent, 25-30% silicone degumming agent, 15-25% swelling agent, and 2-5% charge neutralizing agent.

[0024] The content of the diluent may be, but is not limited to, 30%, 33%, 35%, 37%, 40%, 42%, 45%, 47%, 50%, 53%, 55%, 58%, or 60%. The diluent is white mineral oil, and further, the diluent is selected from at least one of No. 3 white mineral oil, No. 5 white mineral oil, No. 7 white mineral oil, No. 10 white mineral oil, and No. 15 white mineral oil.

[0025] The content of the silicone degumming agent can be, but is not limited to, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, or 40%. The silicone degumming agent is a silicone-based end-capped polyether compound. The structural formula of the silicone-based end-capped polyether compound is shown in Formula I or Formula II, where n is a natural number from 3 to 20, m is a natural number from 6 to 16, and n1 is a natural number from 8 to 25. As an example, the silicone-based end-capped polyether compound can be a single-hydroxyl-terminated polydimethylsiloxane, with CAS number 207308-30-3 and a viscosity of 5 to 20 cp, etc.

[0026]

[0027] Formula I Formula II The content of the swelling agent may be, but is not limited to, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, or 40%. The swelling agent is an alkyl-substituted intracyclic siloxane, selected from at least one of octamethylcyclotetrasiloxane, dodecylcyclohexasiloxane, tetradecylcycloheptasiloxane, hexadecylcyclooctasiloxane, octadecylcyclononasiloxane, and icosylcyclodecasiloxane.

[0028] The content of the charge neutralizer may be, but is not limited to, 1%, 2%, 3%, 4%, 5%, or 6%. The charge neutralizer is an acid ester compound, and further, the charge neutralizer is selected from at least one of polyethylene glycol oleate, polyethylene glycol laurate, sorbitan oleate, sorbitan stearate, and ethoxylated fatty acid esters. When preparing the thermally conductive silicone test fixture cleaning agent of the present invention, silicone degumming agent, swelling agent and charge neutralizing agent can be added to the diluent and mixed evenly.

[0029] To better illustrate the purpose, technical solution, and beneficial effects of this invention, the invention will be further described below with reference to specific embodiments. It should be noted that the methods described below are further explanations of this invention and should not be construed as limiting it.

[0030] Example 1 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 40% No. 5 white mineral oil, 35% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 21% dodecylcyclohexasiloxane, and 4% polyethylene glycol laurate.

[0031] Example 2 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 60% No. 5 white mineral oil, 20% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 18% dodecylcyclohexasiloxane, and 2% polyethylene glycol laurate.

[0032] Example 3 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 50% No. 5 white mineral oil, 30% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 15% dodecylcyclohexasiloxane, and 5% polyethylene glycol laurate.

[0033] Example 4 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 50% No. 5 white mineral oil, 30% of the silicone-based end-capped polyether compound shown in Formula II (m = 7, n1 = 10), 15% dodecylcyclohexasiloxane, and 5% polyethylene glycol laurate.

[0034] Example 5 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 50% No. 5 white mineral oil, 16% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 14% of a silicone-based end-terminated polyether compound of Formula II (m = 7, n1 = 10), 15% dodecylcyclohexasiloxane, and 5% polyethylene glycol laurate.

[0035] Example 6 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 35% #7 white mineral oil, 10% #10 white mineral oil, 32% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 17% dodecylcyclohexasiloxane, and 6% sorbitan stearate.

[0036] Example 7 This embodiment describes a cleaning agent for a thermally conductive silicone testing fixture. The raw materials used in its preparation include, by mass percentage: 50% No. 5 white mineral oil, 30% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 15% octamethylcyclotetrasiloxane, and 5% sorbitan oleate.

[0037] Comparative Example 1 This comparative example is a cleaning agent for a thermally conductive silicone testing fixture. Its preparation raw materials, by mass percentage, include 60% No. 5 white mineral oil, 34% dodecylcyclohexasiloxane, and 6% polyethylene glycol laurate.

[0038] Comparative Example 2 This comparative example is a cleaning agent for a thermally conductive silicone testing tool. Its preparation raw materials, by mass percentage, include 50% No. 5 white mineral oil, 44% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), and 6% polyethylene glycol laurate.

[0039] Comparative Example 3 This comparative example is a cleaning agent for a thermally conductive silicone testing fixture. Its preparation raw materials, by mass percentage, include 42% No. 5 white mineral oil, 36% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), and 22% dodecylcyclohexasiloxane.

[0040] Comparative Example 4 This comparative example is a cleaning agent for a thermally conductive silicone testing tool. Its raw materials, by mass percentage, include 40% No. 5 white mineral oil, 35% hydroxyl-terminated polydimethylsiloxane (CAS No. 207308-30-3), 21% dodecyl polysiloxane, and 4% polyethylene glycol laurate.

[0041] Comparative Example 5 This comparative example is a cleaning agent for a thermally conductive silicone testing tool. Its raw materials, by mass percentage, include 40% No. 5 white mineral oil, 35% polydimethylsiloxane (chemical formula [(CH3)2SiO]6), 21% dodecylcyclohexasiloxane, and 4% polyethylene glycol laurate.

[0042] Comparative Example 6 This comparative example is a cleaning agent for a thermally conductive silicone testing tool. Its preparation raw materials, by mass percentage, include 40% No. 5 white mineral oil, 35% ammonium hydrofluoric acid (chemical formula NH4HF2), 21% dodecylcyclohexasiloxane, and 4% polyethylene glycol laurate.

[0043] After thoroughly mixing the components from Examples 1-7 and Comparative Examples 1-6, each component was placed in a cleaning tank. Metal test fixtures of the same type, coated with the same thermally conductive silicone gel, were placed in each tank. The fixtures were ultrasonically cleaned at 100 kHz at room temperature for 2.0 h and then dried at 60 °C for 0.5 h. The morphology of the metal test fixtures was observed, and the weight of the metal test fixtures before and after cleaning, as well as the surface roughness of the coating before and after cleaning, were measured. The results are shown in Table 1. Wherein, m0 is the weight of the metal test fixture body without thermally conductive silicone gel coating; m1 is the weight of the metal test fixture coated with thermally conductive silicone gel before cleaning; m2 is the weight of the metal test fixture coated with thermally conductive silicone gel after cleaning; R1 is the surface roughness of the coating of the metal test fixture without thermally conductive silicone gel coating; and R2 is the surface roughness of the coating of the metal test fixture coated with thermally conductive silicone gel after cleaning.

[0044] Table 1. Cleaning effect of the cleaning agents in Examples 1-7 and Comparative Examples 1-6

[0045] As shown in Table 1, the raw materials for preparing the cleaning agent of the present invention contain a degumming agent of silicon-based end-capped polyether compound, a swelling agent of alkyl-substituted intracyclic siloxane, and a charge neutralizing agent of acid ester compound. It can not only efficiently remove thermally conductive silicone gel from the surface of metal tooling, but also does not damage the surface of metal tooling.

[0046] In Comparative Examples 1-5, adhesive residue prevented accurate roughness testing. Furthermore, the degumming agent in Comparative Example 5, polydimethylsiloxane, only has silicon-oxygen bonds in its main molecular chain, unlike Formulas I, II, or III which possess both silicon-oxygen and carbon-carbon amphiphilic structures, resulting in unsatisfactory adhesive removal. Comparative Example 6 used a corrosive degumming agent; while its adhesive removal effect was acceptable, the corrosion was severe, and ammonium hydrofluoric acid participated in the reaction. After 20 repeated uses, the component decreased, and the cleaning effect deteriorated.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A cleaning agent for a thermally conductive silicone testing fixture, characterized in that, The raw materials for preparation include, by mass percentage, 30-60% diluent, 20-40% silicone degumming agent, 10-40% swelling agent and 1-6% charge neutralizing agent. The silicone degumming agent is a silicone-based end-capped polyether compound, the swelling agent is an alkyl-substituted intracyclic siloxane, and the charge neutralizing agent is an acid ester compound.

2. The cleaning agent for the thermally conductive silicone testing fixture according to claim 1, characterized in that, It comprises, by weight percentage, 35-65% diluent, 20-30% silicone degumming agent, 10-30% swelling agent, and 1-5% charge neutralizer.

3. The cleaning agent for the thermally conductive silicone testing fixture according to claim 1, characterized in that, It comprises, by weight percentage, 40-55% diluent, 25-30% silicone degumming agent, 15-25% swelling agent, and 2-5% charge neutralizer.

4. The cleaning agent for the thermally conductive silicone testing fixture according to claim 1, characterized in that, The structural formula of the silicon-based end-capped polyether compound is shown in Formula I or Formula II, where n is a natural number from 3 to 20, m is a natural number from 6 to 16, and n1 is a natural number from 8 to 25. Formula I and Formula II.

5. The cleaning agent for the thermally conductive silicone testing fixture according to claim 1, characterized in that, The diluent is white mineral oil.

6. The cleaning agent for the thermally conductive silicone testing fixture according to claim 5, characterized in that, The diluent is selected from at least one of 3# white mineral oil, 5# white mineral oil, 7# white mineral oil, 10# white mineral oil and 15# white mineral oil.

7. The cleaning agent for thermally conductive silicone testing fixtures according to claim 1, characterized in that, The swelling agent is selected from at least one of octamethylcyclotetrasiloxane, dodecylcyclohexasiloxane, tetradecylcycloheptasiloxane, hexadecylcyclooctasiloxane, octadecylcyclononasiloxane, and icosylcyclodecasiloxane.

8. The cleaning agent for the thermally conductive silicone testing fixture according to claim 1, characterized in that, The charge neutralizer is selected from at least one of polyethylene glycol oleate, polyethylene glycol laurate, sorbitan oleate, sorbitan stearate, and ethoxylated fatty acid esters.

9. The application of the thermally conductive silicone testing fixture cleaning agent according to any one of claims 1 to 8 on a thermally conductive silicone testing fixture, characterized in that, The silicone testing fixture is immersed in the thermally conductive silicone testing fixture cleaning agent and then ultrasonically cleaned.

10. The application according to claim 9, characterized in that, The thermally conductive silicone testing fixture is a metal testing fixture with a surface coated with a silicone composition, wherein the silicone composition includes a silicone polymer, a thermally conductive powder, and a powder surface treatment agent.

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