Cable material for new energy charging pile and preparation method thereof

Abstract

The invention provides a cable material for a new energy charging pile and a preparation method of the cable material. The cable material is prepared from the following components: 25 to 35 percent of hydrogenated silicone rubber, 20 to 30 percent of poly (butylene succinate), 6 to 10 percent of carboxymethyl chitosan, 3 to 7 percent of rosemary phenolic acid ester, 3 to 7 percent of nano cellulose, 2 to 6 percent of polyglycerol polyricinoleate, 2 to 6 percent of tannic acid, 5 to 15 percent of aluminum hypophosphite, 2 to 4 percent of hindered amine light stabilizer, 2 to 4 percent of zinc oxide and 2 to 4 percent of titanate coupling agent. The hydrogenated silicone rubber and the poly (butylene succinate) are compounded to form an interpenetrating network structure, the polyglycerol polyricinoleate improves the processing and low temperature resistance of the material, the coupling agent optimizes the interface between the filler and the matrix, and multi-dimensional innovative design is performed from the molecular structure to the overall performance of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of cable materials, and in particular to a cable material for a new energy charging pile and a preparation method thereof. Background Art

[0002] With the booming global new energy vehicle industry, charging piles, as critical infrastructure for electric vehicle charging, are becoming increasingly important for their performance, stability, and safety. In new energy vehicle charging pile systems, power cables, serving as the bridge connecting the charging piles to the electric vehicles, must not only withstand the demands of high current and high voltage transmission but also maintain long-term stable performance in a variety of complex environmental conditions, particularly high temperatures.

[0003] Cable materials for new energy charging piles refer to cable materials used to connect charging piles and electric vehicles. Their performance and characteristics are crucial to ensuring the safety and efficiency of the charging process. These materials need to meet a series of strict requirements, including insulation, flame retardancy, and high and low temperature resistance.

[0004] Polyvinyl chloride (PVC), a widely used cable insulation material, plays a key role in the manufacture of power cables for new energy vehicle charging piles due to its excellent insulation properties, processability, and cost-effectiveness. However, traditional PVC materials face serious aging issues when used under high-temperature conditions. This aging phenomenon is primarily manifested in a decrease in the material's tensile strength and tensile strain at break, as well as an excessively large rate of change in tensile strength and tensile strain at break after aging, which significantly impacts the service life and safety performance of charging pile power cables. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a cable material for a new energy charging pile and a preparation method thereof.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The present application discloses a cable material for a new energy charging pile. The components of the cable material are as follows, in weight percentage: 25-35% hydrogenated silicone rubber, 20-30% polybutylene succinate, 6-10% carboxymethyl chitosan, 3-7% rosmarinate, 3-7% nanocellulose, 2-6% polyglycerol ricinoleate, 2-6% tannic acid, 5-15% aluminum hypophosphite, 2-4% hindered amine light stabilizer, 2-4% zinc oxide and 2-4% titanate coupling agent.

[0008] Preferably, the components of the cable material are as follows, in weight percentage: 30% hydrogenated silicone rubber, 25% polybutylene succinate, 8% carboxymethyl chitosan, 5% rosmarinate, 5% nanocellulose, 4% polyglycerol ricinoleate, 4% tannic acid, 10% aluminum hypophosphite, 3% hindered amine light stabilizer, 3% zinc oxide and 3% titanate coupling agent.

[0009] Preferably, the preparation method of the hydrogenated silicone rubber is as follows:

[0010] a1. Weigh polymethylhydrogensiloxane, vinyl-terminated polydimethylsiloxane, and chloroplatinic acid-isopropanol solution in proportion, wherein: the hydrogen content of polymethylhydrogensiloxane is 0.1%-0.3%, the vinyl content of vinyl-terminated polydimethylsiloxane is 0.1%-0.5%, and the platinum content of chloroplatinic acid-isopropanol solution is 1.8-2.2%;

[0011] a2. Add polymethyl hydrogen siloxane and vinyl-terminated polydimethylsiloxane into a reaction kettle, stir evenly at 80-100°C, then slowly dropwise add chloroplatinic acid-isopropanol solution, raise the temperature to 100-120°C, stir and react for 3-5 hours. After the reaction is completed, cool to room temperature and remove unreacted monomers and oligomers by vacuum distillation to obtain hydrogenated silicone rubber.

[0012] Preferably, the preparation method of the carboxymethyl chitosan is as follows:

[0013] b1. Take 10g of chitosan with a deacetylation degree of 92%, add 100mL of 2% sodium hydroxide solution, stir to fully swell it, then add 20g of chloroacetic acid slowly to the solution, control the temperature to 50°C, continue stirring and react for 6h, during which sodium hydroxide solution is added to maintain the system pH at 9-10;

[0014] b2. After the reaction, the reactor was poured into an 80% by volume ethanol solution for precipitation, and the filter cake was collected by filtration. The filter cake was washed three times with an 80% by volume ethanol solution, and then the filter cake was dispersed in deionized water and dialyzed for 48 hours using a dialysis bag with a molecular weight cutoff of 8000-14000. The dialyzed product was freeze-dried to obtain carboxymethyl chitosan.

[0015] Preferably, the preparation method of the rosmarinic acid ester is as follows:

[0016] c1. Dried rosemary leaves were crushed and then added with a 70% ethanol solution at a solid-liquid ratio of 1:10 (g / mL). The mixture was ultrasonically extracted at 60°C for 2 h. The filtrate was filtered and the ethanol was removed by vacuum distillation to obtain a crude extract of rosemary phenolic acids.

[0017] c2. Sulfuric acid (1%-2% by mass of the crude extract) and excess ethanol are added to the crude extract of rosmarinic phenolic acid, and the mixture is stirred at 70-80° C. for 4-6 hours to carry out an ester exchange reaction. After the reaction is completed, the reaction solution is cooled, the pH is adjusted to neutral with a saturated sodium carbonate solution, and then extracted three times with ethyl acetate. The organic phases are combined, dried over anhydrous sodium sulfate, and the ethyl acetate is removed by distillation under reduced pressure. The mixture is then subjected to silica gel column chromatography to obtain rosmarinic phenolic acid esters.

[0018] Preferably, the eluent in the silica gel column chromatography step is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 3:1.

[0019] This application also discloses a method for preparing a cable material for a new energy charging pile, comprising the following steps:

[0020] S1. Add nanocellulose, carboxymethyl chitosan, and tannic acid into deionized water respectively, and ultrasonically disperse for 30 minutes to obtain pre-dispersed solutions of each component;

[0021] S2. dissolving rosmarinol ester in ethanol to obtain a rosmarinol ester solution;

[0022] S3, mixing the hindered amine light stabilizer, zinc oxide, aluminum hypophosphite and titanate coupling agent in proportion;

[0023] S4. Add hydrogenated silicone rubber and polybutylene succinate into a two-roll rubber mixer, mix at 120°C for 5 minutes, then add polyglycerol castor oil ester, the solution obtained in S1, the solution obtained in S2, and the mixture obtained in S3, continue mixing for 15 minutes, and finally add 0.5-1% of the mass of hydrogenated silicone rubber as a catalyst, mix for 5 minutes, and then hot-press at 120°C and a pressure of 10 MPa for 10 minutes to obtain the cable material for new energy charging piles.

[0024] Preferably, the catalyst added in step S4 is chloroplatinic acid-triethanolamine.

[0025] The beneficial effects of the present invention are:

[0026] Hydrogenated silicone rubber has excellent high-temperature resistance (long-term operating temperatures can reach -60°C to 180°C), weather resistance, and hydrophobicity. The silicon-oxygen bonds in its molecular structure are highly stable, maintaining stable performance in complex outdoor environments. It can also achieve cross-linking through a silicon-hydrogen addition reaction, enhancing the overall material performance and serving as a key component for improving the environmental adaptability of cable materials. Polybutylene succinate (PBS) is a biodegradable polyester made from biomass, in line with green environmental protection concepts. It has excellent mechanical and processing properties and, when combined with hydrogenated silicone rubber, can form an interpenetrating network structure, which helps improve the tensile strength and tensile stress at break of cable materials while reducing their reliance on petroleum-based raw materials.

[0027] Carboxymethyl chitosan is modified from natural chitin. The introduction of carboxymethyl groups into the molecule imparts water solubility, film-forming properties, antibacterial properties, and a certain degree of flame retardancy. In cable materials, it enhances the cable's resistance to microbial attack. Decomposition at high temperatures produces nitrogen- and carbon-containing products, which promote the formation of a carbonized layer, aid in flame retardancy, and improve the cable's overall performance. Rosmarinol esters, extracted from natural rosemary, contain multiple phenolic hydroxyl groups and offer excellent antioxidant properties. They can capture thermal oxidative aging free radicals and offer a certain degree of UV resistance, significantly extending the cable's service life.

[0028] Nanocellulose is a bio-based nanomaterial with high specific strength, high specific modulus, and large specific surface area. As a reinforcing agent, it significantly improves the tensile strength, flexural modulus, and other mechanical properties of cable materials. It also enhances the material's thermal stability and increases cable durability. The long-chain fatty acid ester and polyol structure of polyglycerol ricinoleate improve the material's processing properties, increasing its flexibility and fluidity while lowering processing temperatures. It also enhances the material's low-temperature resistance, keeping the cable soft and flexible in cold environments.

[0029] Tannic acid contains multiple phenolic hydroxyl groups, which can synergize with rosmarinol phenolates to combat aging and capture free radicals. Its benzene ring and carboxyl groups promote surface carbonization at high temperatures, aiding flame retardancy. It is a natural ingredient with both anti-aging and flame retardant properties. Inorganic fillers like nanocellulose face interfacial compatibility issues with matrix resins (hydrogenated silicone rubber, PBS). Titanate coupling agents can improve the interfacial bonding between the two. One end of the titanate coupling agent reacts with the filler's surface hydroxyl groups, while the other end physically or chemically interacts with the matrix resin, evenly dispersing the filler throughout the matrix and fully exerting its reinforcing properties, improving the overall performance of the cable material. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] Example 1:

[0032] This embodiment discloses a cable material for a new energy charging pile. The components of the cable material are as follows, in weight percentage: 30% hydrogenated silicone rubber, 20% polybutylene succinate, 6% carboxymethyl chitosan, 3% rosmarinate, 3% nanocellulose, 6% polyglycerol ricinoleate, 6% tannic acid, 14% aluminum hypophosphite, 4% hindered amine light stabilizer, 4% zinc oxide, and 4% titanate coupling agent.

[0033] The preparation method of hydrogenated silicone rubber is as follows:

[0034] a1. Weigh polymethylhydrogensiloxane, vinyl-terminated polydimethylsiloxane, and chloroplatinic acid-isopropanol solution in proportion, wherein: the hydrogen content of polymethylhydrogensiloxane is 0.1%-0.3%, the vinyl content of vinyl-terminated polydimethylsiloxane is 0.1%-0.5%, and the platinum content of chloroplatinic acid-isopropanol solution is 1.8-2.2%;

[0035] a2. Add polymethyl hydrogen siloxane and vinyl-terminated polydimethylsiloxane into a reaction kettle, stir evenly at 80-100°C, then slowly dropwise add chloroplatinic acid-isopropanol solution, raise the temperature to 100-120°C, stir and react for 3-5 hours. After the reaction is completed, cool to room temperature and remove unreacted monomers and oligomers by vacuum distillation to obtain hydrogenated silicone rubber.

[0036] The preparation method of carboxymethyl chitosan is as follows:.

[0037] b1. Take 10g of chitosan with a deacetylation degree of 92%, add 100mL of 2% sodium hydroxide solution, stir to fully swell it, then add 20g of chloroacetic acid slowly to the solution, control the temperature to 50°C, continue stirring and react for 6h, during which sodium hydroxide solution is added to maintain the system pH at 9-10;

[0038] b2. After the reaction, the reactor was poured into an 80% by volume ethanol solution for precipitation, and the filter cake was collected by filtration. The filter cake was washed three times with an 80% by volume ethanol solution, and then the filter cake was dispersed in deionized water and dialyzed for 48 hours using a dialysis bag with a molecular weight cutoff of 8000-14000. The dialyzed product was freeze-dried to obtain carboxymethyl chitosan.

[0039] The preparation method of rosmarinol ester is as follows:

[0040] c1. Dried rosemary leaves were crushed and then added with a 70% ethanol solution at a solid-liquid ratio of 1:10 (g / mL). The mixture was ultrasonically extracted at 60°C for 2 h. The filtrate was filtered and the ethanol was removed by vacuum distillation to obtain a crude extract of rosemary phenolic acids.

[0041] c2. Sulfuric acid (1%-2% by mass of the crude extract) and excess ethanol are added to the crude extract of rosmarinic phenolic acid, and the mixture is stirred at 70-80° C. for 4-6 hours to carry out an ester exchange reaction. After the reaction is completed, the reaction solution is cooled, the pH is adjusted to neutral with a saturated sodium carbonate solution, and then extracted three times with ethyl acetate. The organic phases are combined, dried over anhydrous sodium sulfate, and the ethyl acetate is removed by distillation under reduced pressure. The mixture is then subjected to silica gel column chromatography to obtain rosmarinic phenolic acid esters.

[0042] This embodiment also discloses a method for preparing a cable material for a new energy charging pile, comprising the following steps:

[0043] S1. Add nanocellulose, carboxymethyl chitosan, and tannic acid into deionized water respectively, and ultrasonically disperse for 30 minutes to obtain pre-dispersed solutions of each component;

[0044] S2. dissolving rosmarinol ester in ethanol to obtain a rosmarinol ester solution;

[0045] S3, mixing the hindered amine light stabilizer, zinc oxide, aluminum hypophosphite and titanate coupling agent in proportion;

[0046] S4. Add hydrogenated silicone rubber and polybutylene succinate into a two-roll rubber mixer, mix at 120°C for 5 minutes, then add polyglycerol castor oil ester, the solution obtained in S1, the solution obtained in S2, and the mixture obtained in S3, continue mixing for 15 minutes, and finally add 0.5-1% of the mass of hydrogenated silicone rubber chloroplatinic acid-triethanolamine catalyst, mix for 5 minutes, and then hot-press at 120°C and a pressure of 10 MPa for 10 minutes to obtain cable materials for new energy charging piles.

[0047] Example 2:

[0048] This embodiment discloses a cable material for a new energy charging pile. The only difference between this embodiment and Example 1 is the content ratio of each component. The composition of the cable material is as follows, in weight percentage: 35% hydrogenated silicone rubber, 30% polybutylene succinate, 10% carboxymethyl chitosan, 5% rosmarinic acid ester, 5% nanocellulose, 2% polyglycerol ricinoleate, 2% tannic acid, 5% aluminum hypophosphite, 2% hindered amine light stabilizer, 2% zinc oxide, and 2% titanate coupling agent.

[0049] Example 3:

[0050] This embodiment discloses a cable material for a new energy charging pile. The only difference between the cable material and Example 1 is the content ratio of each component. The composition of the cable material is as follows, in weight percentage: 30% hydrogenated silicone rubber, 25% polybutylene succinate, 8% carboxymethyl chitosan, 5% rosmarinate, 5% nanocellulose, 4% polyglycerol ricinoleate, 4% tannic acid, 10% aluminum hypophosphite, 3% hindered amine light stabilizer, 3% zinc oxide and 3% titanate coupling agent.

[0051] Comparative Example 1:

[0052] A cable material for a new energy charging pile. The cable material differs from Example 3 only in that hydrogenated silicone rubber is not added, and the remaining components are increased in equal proportions until the total component content increases to 100%.

[0053] Comparative Example 2:

[0054] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that ordinary silicone rubber is used instead of hydrogenated silicone rubber.

[0055] Comparative Example 3:

[0056] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that polybutylene succinate is not added, and the remaining components are increased in equal proportions until the total component content increases to 100%.

[0057] Comparative Example 4:

[0058] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that carboxymethyl chitosan is not added, and the remaining components are increased in equal proportions until the total component content increases to 100%.

[0059] Comparative Example 5:

[0060] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that ordinary chitosan is used instead of carboxymethyl chitosan.

[0061] Comparative Example 6:

[0062] A cable material for a new energy charging pile. The cable material differs from Example 3 only in that rosmarinol ester is not added, and the remaining components are increased in equal proportions until the total component content increases to 100%.

[0063] Comparative Example 7:

[0064] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that nanocellulose is not added, and the remaining components are increased in proportion until the total component content increases to 100%.

[0065] Comparative Example 8:

[0066] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that no polyglycerol ricinoleate is added, and the remaining components are increased in equal proportions until the total component content increases to 100%.

[0067] Comparative Example 9:

[0068] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that tannic acid is not added, and the remaining components are increased in equal proportions until the total component content increases to 100%.

[0069] Comparative Example 10:

[0070] A cable material for a new energy charging pile. The difference between the cable material and Example 3 is that no hindered amine light stabilizer is added, and the remaining components are increased in proportion until the total component content increases to 100%.

[0071] The cables made from the cable materials obtained in Examples 1-3 and Comparative Examples 1-10 were subjected to performance tests to measure the comprehensive performance of the cables. The evaluation standard for aging resistance was based on the tensile strength retention rate after 1000 hours of xenon lamp aging treatment. The results are shown in Table 1.

[0072] Table 1 Performance parameters of the cables obtained in Examples 1-3 and Comparative Examples 1-10

[0073]

[0074]

[0075] As shown in Table 1, the absence of hydrogenated silicone rubber significantly impacts the flame retardancy, tensile strength, fracture resistance, and aging resistance of the cable. Substituting ordinary silicone rubber for hydrogenated silicone rubber also has a certain impact on the flame retardancy, tensile strength, fracture resistance, and aging resistance of the cable.

[0076] The absence of polybutylene succinate has a significant impact on the tensile strength and fracture resistance of the cable obtained from the cable material, indicating that polybutylene succinate and hydrogenated silicone rubber may have a synergistic effect to improve the tensile strength and fracture resistance of the cable.

[0077] The absence of rosmarinol esters has a certain impact on the flame retardancy and aging resistance of the cable obtained from the cable material. The absence of polyglycerol ricinoleate has a certain impact on the tensile strength of the cable obtained from the cable material. The absence of tannic acid has a certain impact on the flame retardancy of the cable obtained from the cable material.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A cable material for a new energy charging pile, characterized in that: The cable material comprises the following components, in percentage by weight: 25-35% hydrogenated silicone rubber, 20-30% polybutylene succinate, 6-10% carboxymethyl chitosan, 3-7% rosmarinic acid ester, 3-7% nanocellulose, 2-6% polyglycerol ricinoleate, 2-6% tannic acid, 5-15% aluminum hypophosphite, 2-4% hindered amine light stabilizer, 2-4% zinc oxide and 2-4% titanate coupling agent.

2. The cable material for new energy charging pile according to claim 1, characterized in that: The cable material comprises, by weight percentage, 30% hydrogenated silicone rubber, 25% polybutylene succinate, 8% carboxymethyl chitosan, 5% rosmarinate, 5% nanocellulose, 4% polyglycerol ricinoleate, 4% tannic acid, 10% aluminum hypophosphite, 3% hindered amine light stabilizer, 3% zinc oxide, and 3% titanate coupling agent.

3. The cable material for new energy charging pile according to claim 1 or 2, characterized in that: The preparation method of the hydrogenated silicone rubber is as follows: a1. Weigh polymethylhydrogensiloxane, vinyl-terminated polydimethylsiloxane, and chloroplatinic acid-isopropanol solution in proportion, wherein: the hydrogen content of polymethylhydrogensiloxane is 0.1%-0.3%, the vinyl content of vinyl-terminated polydimethylsiloxane is 0.1%-0.5%, and the platinum content of chloroplatinic acid-isopropanol solution is 1.8-2.2%; a2. Add polymethyl hydrogen siloxane and vinyl-terminated polydimethylsiloxane into a reaction kettle, stir evenly at 80-100°C, then slowly dropwise add chloroplatinic acid-isopropanol solution, raise the temperature to 100-120°C, stir and react for 3-5 hours. After the reaction is completed, cool to room temperature and remove unreacted monomers and oligomers by vacuum distillation to obtain hydrogenated silicone rubber.

4. The cable material for new energy charging pile according to claim 3, characterized in that: The preparation method of the carboxymethyl chitosan is as follows: b1. Take 10g of chitosan with a deacetylation degree of 92%, add 100mL of 2% sodium hydroxide solution, stir to fully swell it, then add 20g of chloroacetic acid slowly to the solution, control the temperature to 50°C, continue stirring and react for 6h, during which sodium hydroxide solution is added to maintain the system pH at 9-10; b2. After the reaction, the reactor was poured into an 80% by volume ethanol solution for precipitation, and the filter cake was collected by filtration. The filter cake was washed three times with an 80% by volume ethanol solution, and then the filter cake was dispersed in deionized water and dialyzed for 48 hours using a dialysis bag with a molecular weight cutoff of 8000-14000. The dialyzed product was freeze-dried to obtain carboxymethyl chitosan.

5. The cable material for new energy charging pile according to claim 3, characterized in that: The preparation method of the rosmarinic acid ester is as follows: c1. Dried rosemary leaves were crushed and then added with a 70% ethanol solution at a solid-liquid ratio of 1:10 (g / mL). The mixture was ultrasonically extracted at 60°C for 2 h. The filtrate was filtered and the ethanol was removed by vacuum distillation to obtain a crude extract of rosemary phenolic acids. c2. Sulfuric acid (1%-2% by mass of the crude extract) and excess ethanol are added to the crude extract of rosmarinic phenolic acid, and the mixture is stirred at 70-80° C. for 4-6 hours to carry out an ester exchange reaction. After the reaction is completed, the reaction solution is cooled, the pH is adjusted to neutral with a saturated sodium carbonate solution, and then extracted three times with ethyl acetate. The organic phases are combined, dried over anhydrous sodium sulfate, and the ethyl acetate is removed by distillation under reduced pressure. The mixture is then subjected to silica gel column chromatography to obtain rosmarinic phenolic acid esters.

6. The cable material for new energy charging pile according to claim 5, characterized in that: The eluent in the silica gel column chromatography step was a petroleum ether-ethyl acetate mixed solution with a volume ratio of 3:

1.

7. A method for preparing a cable material for a new energy charging pile according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1. Add nanocellulose, carboxymethyl chitosan, and tannic acid into deionized water respectively, and ultrasonically disperse for 30 minutes to obtain pre-dispersed solutions of each component; S2. dissolving rosmarinol ester in ethanol to obtain a rosmarinol ester solution; S3, mixing the hindered amine light stabilizer, zinc oxide, aluminum hypophosphite and titanate coupling agent in proportion; S4. Add hydrogenated silicone rubber and polybutylene succinate into a two-roll rubber mixer, mix at 120°C for 5 minutes, then add polyglycerol castor oil ester, the solution obtained in S1, the solution obtained in S2, and the mixture obtained in S3, continue mixing for 15 minutes, and finally add 0.5-1% of the mass of hydrogenated silicone rubber as a catalyst, mix for 5 minutes, and then hot-press at 120°C and a pressure of 10 MPa for 10 minutes to obtain the cable material for new energy charging piles.

8. The method for preparing a cable material for a new energy charging pile according to claim 7, characterized in that: The catalyst added in step S4 is chloroplatinic acid-triethanolamine.

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