Soft antibacterial melamine foam plastic and preparation method thereof

Abstract

The invention relates to soft antibacterial melamine foam plastic and a preparation method thereof, and belongs to the technical field of preparation of melamine materials. The soft antibacterial melamine foam plastic is prepared from the following components: melamine, paraformaldehyde, a modifier, an emulsifier, a curing agent, a foaming agent, a surfactant, a foam stabilizer and an antibacterial agent. The melamine foamed plastic prepared by the preparation method disclosed by the invention has relatively good antibacterial property and flame retardant property.

Description

Technical Field

[0001] The invention belongs to the technical field of melamine material preparation, and relates to a soft antibacterial melamine foam plastic and a preparation method thereof. Background Art

[0002] Melamine foam (also known as melamine foam) is a soft thermosetting foam plastic with a nano-scale three-dimensional network cross-linked structure made by microwave foaming of alkaline melamine formaldehyde resin through a special process. It is a new type of material with good flame retardant, sound insulation and thermal insulation properties. It is widely used in construction, transportation, industry, vehicle manufacturing, acoustic engineering, aerospace, aviation, navigation and other fields.

[0003] Melamine foam plastics are mainly divided into soft melamine foam, semi-rigid melamine foam and rigid melamine foam. Compared with traditional thermal insulation foam plastics such as polyethylene, polystyrene and polyurethane, melamine foam plastics have superior flame retardancy, thermal stability, sound insulation and thermal insulation properties: melamine foam plastics can quickly carbonize and coke when exposed to open flames, release non-flammable gases, block the spread of combustion, do not soften during combustion, have no dripping, and have extremely low smoke density. Melamine foam plastics can be used at around 180°C for a long time, and the decomposition temperature exceeds 400°C. Melamine foam plastics have good absorption characteristics for low-frequency noise below 500Hz. In addition, melamine foam plastics also have the advantages of light weight, chemical corrosion resistance, good dimensional stability and good secondary processing. Therefore, melamine foam plastics are widely used in construction, transportation, aviation and other fields, and are currently a new type of environmentally friendly flame retardant material with great development prospects.

[0004] As a new type of thermal insulation material, melamine foam plastic has excellent flame retardant, high temperature resistance and sound insulation properties, and has been widely used in many fields. At present, the domestic industrialization of soft melamine foam plastics has reached the same level as the international level, but the related functional modification research started late. Therefore, in the future, promoting the development of soft melamine foam towards serialization, functionalization and environmental protection will be the main development trend of soft melamine foam plastics. Summary of the invention

[0005] The main purpose of the present invention is to provide a soft antibacterial melamine foam plastic and a preparation method thereof, so as to increase the functionality of the existing soft melamine resin.

[0006] The present invention adopts the following technical solutions to achieve the above purpose:

[0007] A soft antibacterial melamine foam plastic is mainly prepared from the following ingredients:

[0008] Melamine, paraformaldehyde, modifier, emulsifier, curing agent, foaming agent, surfactant, foam stabilizer, antibacterial agent;

[0009] The preparation method of the soft antibacterial melamine foam plastic comprises the following steps:

[0010] Step 1, adding melamine, paraformaldehyde and 2-furan carboxaldehyde into a reaction kettle according to a certain molar ratio, stirring and reacting at 75-85° C. for 1-2 hours, adjusting the pH to 8.5-9.0 after the solution is clarified, reacting for another 0.5-1 hour, and cooling to obtain a prepolymer solution;

[0011] Step 2, adding an emulsifier, a curing agent, a foaming agent, a surfactant, a foam stabilizer, and an antibacterial agent to the prepolymer solution obtained in step 1, placing the mixture in a high-speed stirrer and mixing the mixture evenly to obtain a prefabricated foaming liquid;

[0012] Step 3, placing the prefabricated foaming liquid obtained in step 2 in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

[0013] Preferably, in step 1, the molar ratio of melamine, paraformaldehyde and 2-furancarboxaldehyde is 1:(1.5-2.5):(0.3-0.5);

[0014] Preferably, in step 2, 6-10 parts by weight of emulsifier, 5-8 parts by weight of curing agent, 15-20 parts by weight of foaming agent, 1-2 parts by weight of surfactant, 3-5 parts by weight of foam stabilizer and 0.8-1.2 parts by weight of antibacterial agent are added to every 100 parts by weight of prepolymer solution.

[0015] Preferably, the emulsifier in step 2 is one or more of glycerol fatty acid ester, sorbitol fatty acid ester, and Tween 80;

[0016] Preferably, the curing agent in step 2 is p-toluenesulfonic acid;

[0017] Preferably, the foaming agent in step 2 is one or more of n-pentane, n-hexane, petroleum ether and trichlorofluoromethane.

[0018] Preferably, the surfactant in step 2 is sodium lauryl sulfate or sodium fatty alcohol polyoxyethylene ether sulfate;

[0019] Preferably, the foam stabilizer in step 2 is polyacrylamide or polyvinyl alcohol;

[0020] Preferably, the antibacterial agent in step 2 is a modified organosilicon long-chain quaternary ammonium salt.

[0021] The preparation method of the modified organosilicon long-chain quaternary ammonium salt is:

[0022] Step a, adding a mixture of long-chain alkyl silicone oil, dicyclohexylmethane diisocyanate and triethylamine into a reaction kettle, adding a mixed solvent containing isopropanol, methanol and dimethyl sulfoxide, stirring and reacting at 70-80° C. for 2-3 hours to obtain an initial reactant;

[0023] Step b, adding glacial acetic acid to the initial reactant obtained in step a, placing in a magnetic stirrer, heating and stirring to 70-80° C., maintaining for 2-2.5 hours, to obtain a modified organosilicon long-chain quaternary ammonium salt.

[0024] Preferably, in step a, the molar ratio of long-chain alkyl silicone oil, dicyclohexylmethane diisocyanate and triethylamine is 1:(0.3-0.5):(1.2-1.5).

[0025] Preferably, the mixed solvent of isopropanol, methanol and dimethyl sulfoxide in step a is added in an amount of 15-20% of the volume of the mixture;

[0026] More preferably, the volume ratio of isopropanol, methanol and dimethyl sulfoxide in the mixed solvent of isopropanol, methanol and dimethyl sulfoxide in step a is (0.2-0.3):1:(3-4).

[0027] Preferably, the amount of glacial acetic acid added in step b is 10-12% of the volume of the initial reactants.

[0028] The present invention has the following technical effects:

[0029] 1. The soft melamine foam plastic prepared by the present invention has good antibacterial properties. Tests have shown that it has significant antibacterial properties against Escherichia coli and Staphylococcus aureus and has good functionality.

[0030] 2. In the preparation of the melamine foam of the present invention, an antibacterial agent, a quaternary ammonium salt of organosilicon, is added. However, the addition of the antibacterial agent will affect the comprehensive properties of the melamine foam to a certain extent, reducing its tensile strength, elongation at break, tear strength and polar oxygen index. Therefore, the melamine foam is modified. The modified organosilicon long-chain quaternary ammonium salt after modification can effectively avoid the above-mentioned problems and ensure the comprehensive properties of the melamine foam. DETAILED DESCRIPTION

[0031] The present invention is further explained below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications to the present invention by those skilled in the art all fall within the scope of protection of the claims of this application.

[0032] Example 1

[0033] Preparation of antibacterial agent (modified silicone long-chain quaternary ammonium salt):

[0034] Step a, adding a mixture of long-chain alkyl silicone oil, dicyclohexylmethane diisocyanate and triethylamine in a molar ratio of 1:0.5:1.5 to a reaction kettle, adding a mixed solvent of isopropanol, methanol and dimethyl sulfoxide in a volume ratio of 0.3:1:4 (the added amount is 20% of the volume of the mixture), stirring and reacting at 80° C. for 3 hours to obtain an initial reactant;

[0035] Step b, adding 12% of the volume of glacial acetic acid to the initial reactants, placing the reactants in a magnetic stirrer, heating and stirring to 80° C., and maintaining the temperature for 2.5 hours to obtain a modified organosilicon long-chain quaternary ammonium salt.

[0036] Preparation of soft antibacterial melamine foam:

[0037] Step 1, adding melamine, paraformaldehyde and 2-furan carboxaldehyde into a reaction kettle at a molar ratio of 1:2.5:0.5, stirring and reacting at 85° C. for 2 hours, adjusting the pH to 9.0 after the solution is clarified, reacting for another 1 hour, and cooling to obtain a prepolymer solution;

[0038] Step 2, adding 10 parts by weight of glycerol fatty acid ester, 8 parts by weight of p-toluenesulfonic acid, 20 parts by weight of n-pentane, 2 parts by weight of sodium lauryl sulfate, 5 parts by weight of polyacrylamide, and 1.2 parts by weight of modified organosilicon long-chain quaternary ammonium salt to 100 parts of the prepolymer solution, placing in a high-speed stirrer and mixing evenly to obtain a prefabricated foaming liquid;

[0039] Step 3, placing the prefabricated foaming liquid in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

[0040] Example 2

[0041] Preparation of antibacterial agent (modified silicone long-chain quaternary ammonium salt):

[0042] Step a, adding a mixture of long-chain alkyl silicone oil, dicyclohexylmethane diisocyanate and triethylamine in a molar ratio of 1:0.3:1.2 to a reaction kettle, adding a mixed solvent of isopropanol, methanol and dimethyl sulfoxide in a volume ratio of 0.2:1:3 (the added amount is 15% of the volume of the mixture), stirring and reacting at 70° C. for 2 hours to obtain an initial reactant;

[0043] Step b, adding 10% of the volume of glacial acetic acid to the initial reactant, placing it in a magnetic stirrer, heating and stirring to 70° C., and maintaining for 2 hours to obtain a modified organosilicon long-chain quaternary ammonium salt.

[0044] Preparation of soft antibacterial melamine foam:

[0045] Step 1, adding melamine, paraformaldehyde and 2-furan carboxaldehyde into a reaction kettle at a molar ratio of 1:1.5:0.3, stirring and reacting at 75° C. for 1 hour, adjusting the pH to 8.5 after the solution is clarified, reacting for another 0.5 hour, and cooling to obtain a prepolymer solution;

[0046] Step 2, adding 6 parts by weight of sorbitol fatty acid ester, 5 parts by weight of p-toluenesulfonic acid, 15 parts by weight of n-hexane, 1 part by weight of fatty alcohol polyoxyethylene ether sodium sulfate, 3 parts by weight of polyvinyl alcohol, and 0.8 parts by weight of modified silicone long-chain quaternary ammonium salt to 100 parts of the prepolymer solution, placing in a high-speed stirrer and mixing evenly to obtain a prefabricated foaming liquid;

[0047] Step 3, placing the prefabricated foaming liquid in a microwave foaming device, subjecting it to microwave radiation for foaming, and then curing and drying it to obtain a soft antibacterial melamine foam plastic. Preparation of soft antibacterial melamine foam plastic:

[0048] Example 3

[0049] Preparation of antibacterial agent (modified silicone long-chain quaternary ammonium salt):

[0050] Step a, adding a mixture of long-chain alkyl silicone oil, dicyclohexylmethane diisocyanate and triethylamine in a molar ratio of 1:0.4:1.3 to a reaction kettle, adding a mixed solvent of isopropanol, methanol and dimethyl sulfoxide in a volume ratio of 0.25:1:3.5 (the added amount is 18% of the volume of the mixture), stirring and reacting at 75° C. for 2.5 hours to obtain an initial reactant;

[0051] Step b, add 11% of the volume of glacial acetic acid to the initial reactants, place in a magnetic stirrer, heat and stir to 75° C., maintain for 2 hours, and obtain modified organosilicon long-chain quaternary ammonium salt.

[0052] Preparation of soft antibacterial melamine foam:

[0053] Step 1, adding melamine, paraformaldehyde and 2-furan carboxaldehyde into a reaction kettle at a molar ratio of 1:2.0:0.4, stirring and reacting at 80° C. for 1.5 hours, adjusting the pH to 9.0 after the solution is clarified, reacting for another 1 hour, and cooling to obtain a prepolymer solution;

[0054] Step 2, adding 8 parts by weight of Tween 80, 7 parts by weight of p-toluenesulfonic acid, 18 parts by weight of trichlorofluoromethane, 1.5 parts by weight of sodium lauryl sulfate, 4 parts by weight of polyvinyl alcohol, and 1.0 part by weight of modified organosilicon long-chain quaternary ammonium salt to 100 parts of the prepolymer solution, placing the mixture in a high-speed stirrer and mixing the mixture uniformly to obtain a prefabricated foaming liquid;

[0055] Step 3, placing the prefabricated foaming liquid in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

[0056] Comparative Example 1

[0057] Preparation of soft antibacterial melamine foam:

[0058] Step 1, adding melamine and paraformaldehyde into a reaction kettle at a molar ratio of 1:2.0, stirring and reacting at 80° C. for 1.5 hours, adjusting the pH to 9.0 after the solution becomes clear, reacting for another hour, and cooling to obtain a prepolymer solution;

[0059] Step 2, adding 8 parts by weight of Tween 80, 7 parts by weight of p-toluenesulfonic acid, 18 parts by weight of trichlorofluoromethane, 1.5 parts by weight of sodium lauryl sulfate, 4 parts by weight of polyvinyl alcohol, and 1.0 part by weight of organosilicon quaternary ammonium salt to 100 parts of the prepolymer solution, placing the mixture in a high-speed stirrer and mixing the mixture uniformly to obtain a prefabricated foaming liquid;

[0060] Step 3, placing the prefabricated foaming liquid in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

[0061] Comparative Example 2

[0062] Preparation of antibacterial agent (modified silicone long-chain quaternary ammonium salt):

[0063] Step a, adding a mixture of long-chain alkyl silicone oil and triethylamine in a molar ratio of 1:1.3 to a reaction kettle, adding a mixed solvent of isopropanol, methanol, and dimethyl sulfoxide in a volume ratio of 0.25:1:3.5 (the added amount is 18% of the volume of the mixture), stirring and reacting at 75° C. for 2.5 hours to obtain an initial reactant;

[0064] Step b, add 11% of the volume of glacial acetic acid to the initial reactants, place in a magnetic stirrer, heat and stir to 75° C., maintain for 2 hours, and obtain modified organosilicon long-chain quaternary ammonium salt.

[0065] Preparation of soft antibacterial melamine foam:

[0066] Step 1, adding melamine, paraformaldehyde and 2-furan carboxaldehyde into a reaction kettle at a molar ratio of 1:2.0:0.4, stirring and reacting at 80° C. for 1.5 hours, adjusting the pH to 9.0 after the solution is clarified, reacting for another 1 hour, and cooling to obtain a prepolymer solution;

[0067] Step 2, adding 8 parts by weight of Tween 80, 7 parts by weight of p-toluenesulfonic acid, 18 parts by weight of trichlorofluoromethane, 1.5 parts by weight of fatty alcohol polyoxyethylene ether sodium sulfate, 4 parts by weight of polyvinyl alcohol, and 1.0 part by weight of modified organosilicon long-chain quaternary ammonium salt to 100 parts of the prepolymer solution, placing in a high-speed stirrer and mixing evenly to obtain a prefabricated foaming liquid;

[0068] Step 3, placing the prefabricated foaming liquid in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

[0069] Comparative Example 3

[0070] Preparation of soft antibacterial melamine foam:

[0071] Step 1, adding melamine and paraformaldehyde into a reaction kettle at a molar ratio of 1:2.0, stirring and reacting at 80° C. for 1.5 hours, adjusting the pH to 9.0 after the solution becomes clear, reacting for another hour, and cooling to obtain a prepolymer solution;

[0072] Step 2, adding 8 parts by weight of Tween 80, 7 parts by weight of p-toluenesulfonic acid, 18 parts by weight of trichlorofluoromethane, 1.5 parts by weight of sodium dodecyl sulfate, 4 parts by weight of polyvinyl alcohol, and 1.0 parts by weight of guanidinomaleic acid hydrochloride to 100 parts of the prepolymer solution, placing the mixture in a high-speed stirrer and mixing the mixture evenly to obtain a prefabricated foaming liquid;

[0073] Step 3, placing the prefabricated foaming liquid in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

[0074] Performance Testing

[0075] 1. Comprehensive performance test of soft melamine foam plastics

[0076] The melamine foam plastics obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were cut into standard samples, and the tensile strength and elongation at break were measured according to GB / T9641-1988, and the oxygen index was measured according to GB / T2406-93.

[0077] Results and analysis: From the results in Table 1, it can be seen that the melamine foam plastic prepared by the present invention has good flame retardant properties and mechanical strength.

[0078] Table 1 Comparison of comprehensive properties of melamine foam plastics

[0079] Foam plastic Tensile strength(kPa) Elongation at break (%) Tear strength (N / m) Polar oxygen index (%) Commercially available 151 159 2.78 29.5 Example 1 147 162 2.43 30.1 Example 2 153 153 2.81 28.5 Example 3 149 158 2.69 31.9 Comparative Example 1 106 129 1.76 22.3 Comparative Example 2 125 132 1.84 23.8 Comparative Example 3 113 121 1.77 22.7

[0080] 2. Antibacterial performance test of soft melamine foam plastics

[0081] The soft melamine foam plastics obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were cut into pieces of 1 cm×1 cm×1 cm, and the antibacterial properties were tested before and after boiling.

[0082] Results and analysis: From the results in Table 2, it can be seen that the melamine foam plastic prepared by the present invention has good antibacterial properties.

[0083] Table 2 Comparison of antibacterial properties of melamine foam plastics

[0084]

Claims

1. A soft antibacterial melamine foam plastic, characterized in that: It is prepared from the following ingredients: melamine, paraformaldehyde, modifier, emulsifier, curing agent, foaming agent, surfactant, foam stabilizer, antibacterial agent; The preparation method of the soft antibacterial melamine foam plastic comprises the following steps: Step 1, adding melamine, paraformaldehyde and 2-furan carboxaldehyde into a reaction kettle at a molar ratio of 1: (1.5-2.5): (0.3-0.5), stirring and reacting at 75-85° C. for 1-2 hours, adjusting the pH to 8.5-9.0 after the solution is clarified, reacting for another 0.5-1 hour, and cooling to obtain a prepolymer solution; Step 2, adding 6-10 parts by weight of emulsifier, 5-8 parts by weight of curing agent, 15-20 parts by weight of foaming agent, 1-2 parts by weight of surfactant, 3-5 parts by weight of foam stabilizer, and 0.8-1.2 parts by weight of antibacterial agent to 100 parts by weight of the prepolymer solution obtained in step 1, placing the mixture in a high-speed stirrer and mixing the mixture uniformly to obtain a prefabricated foaming liquid; Step 3, placing the prefabricated foaming liquid obtained in step 2 in a microwave foaming device, foaming by microwave radiation, and then curing and drying to obtain a soft antibacterial melamine foam plastic.

2. The soft antibacterial melamine foam plastic according to claim 1, characterized in that: In step 2 of the preparation method, the emulsifier is one or more of glycerol fatty acid ester, sorbitol fatty acid ester, and Tween 80.

3. The soft antibacterial melamine foam plastic according to claim 1, characterized in that: In step 2 of the preparation method, the curing agent is p-toluenesulfonic acid.

4. The soft antibacterial melamine foam plastic according to claim 1, characterized in that: In step 2 of the preparation method, the foaming agent is one or more of n-pentane, n-hexane, petroleum ether, and trichlorofluoromethane.

5. The soft antibacterial melamine foam plastic according to claim 1, characterized in that: In step 2 of the preparation method, the surfactant is sodium dodecyl sulfate or sodium fatty alcohol polyoxyethylene ether sulfate.

6. The soft antibacterial melamine foam plastic according to claim 1, characterized in that: In step 2 of the preparation method, the foam stabilizer is polyacrylamide or polyvinyl alcohol.

7. The soft antibacterial melamine foam plastic according to claim 1, characterized in that: In step 2 of the preparation method, the antibacterial agent is a modified organosilicon long-chain quaternary ammonium salt.

8. The soft antibacterial melamine foam plastic according to claim 7, characterized in that: The preparation method of the modified organosilicon long-chain quaternary ammonium salt is: Step a, adding a mixture of long-chain alkyl silicone oil, dicyclohexylmethane diisocyanate and triethylamine in a molar ratio of 1:(0.3-0.5):(1.2-1.5) to a reaction kettle, adding a mixed solvent containing isopropanol, methanol and dimethyl sulfoxide, stirring and reacting at 70-80° C. for 2-3 hours to obtain an initial reactant; Step b, adding 10-12% glacial acetic acid by volume to the initial reactant obtained in step a, placing in a magnetic stirrer, heating and stirring to 70-80° C., maintaining for 2-2.5 hours, to obtain a modified organosilicon long-chain quaternary ammonium salt.

9. The soft antibacterial melamine foam plastic according to claim 8, characterized in that: In step a of the method for preparing the modified organosilicon long-chain quaternary ammonium salt, the amount of the mixed solvent added is 15-20% of the volume of the mixture.

10. The soft antibacterial melamine foam plastic according to claim 8, characterized in that: In the step a of the method for preparing the modified organosilicon long-chain quaternary ammonium salt, the volume ratio of isopropanol, methanol and dimethyl sulfoxide in the mixed solvent is (0.2-0.3):1:(3-4).

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