Mildew-proof polysulfide and method for preparing the same, mildew-proof sealant

Abstract

The present application relates to a long-term mildew-proof polysulfide which can achieve long-term 0-grade mildew-proof effect as a mildew-proof agent added to a sealant. The present application also relates to a preparation method of the mildew-proof polysulfide and a sealant containing the mildew-proof polysulfide.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an anti-mildew polysulfide and its preparation method, as well as an anti-mildew sealant. Background Technology

[0002] Polysulfide sealants, due to their excellent resistance to jet fuel, air impermeability, water impermeability, ozone resistance, natural aging resistance, and reliable adhesion, are widely used for corrosion protection and sealing of aircraft integral fuel tanks, fuel tanks, cockpits, and passenger cabins. They are also widely used in shipbuilding, automobiles, insulated glass, buildings, sewage treatment projects, and structural sealing and other corrosion protection for bridges, highways, and airport pavements. However, polysulfide sealants are prone to mold growth under humid and hot conditions. The growth and spread of mold makes the internal molecular structure of the sealant susceptible to microbial erosion, leading to degradation and deterioration, thus affecting the sealing effect. The fuel (hydrocarbons) in aircraft integral fuel tanks is an energy source for microbial growth and development. Trace amounts of free or dissolved water and other contaminants in the fuel create favorable conditions for microbial growth and reproduction. Microbial corrosion in the fuel tank not only degrades the polysulfide sealant, but more seriously, mold can penetrate the aluminum alloy surface. The acidic substances secreted can cause pitting and crystalline corrosion on the aluminum alloy surface, directly affecting the lifespan of the fuel tank. Therefore, polysulfide sealants should have anti-mildew properties when used in aircraft fuel tanks, ships, and other similar applications.

[0003] Currently, the main solution to the mold prevention problem of sealants is to directly add mold inhibitors. However, because sealants operate in environments with organic solvents such as aviation kerosene for extended periods, small-molecule mold inhibitors may be extracted by the solvents. Therefore, existing mold inhibitors only provide mold prevention in the initial addition stage and cannot achieve long-term mold prevention in oil-resistant environments.

[0004] Therefore, there is an urgent need to develop a mold inhibitor that can prevent mold growth over a long period of time. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a mildew-resistant polysulfide that can prevent mold for a long time. When added to a sealant as a mildew inhibitor, it can achieve a long-term level 0 mildew-resistant effect.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned anti-mildew polysulfide.

[0007] Another object of the present invention is to provide a mildew-resistant sealant containing the above-mentioned mildew-resistant polysulfide.

[0008] To achieve the above objectives, the present invention provides the following technical solution.

[0009] In a first aspect, the present invention provides an anti-mildew polysulfide having an anti-mildew functional group, wherein the anti-mildew functional group includes iodine atoms.

[0010] Iodine atoms possess anti-mold properties, binding to enzyme proteins in microbial cells and disrupting their metabolic functions, thereby killing mold and achieving anti-mold effects. The inventors introduced iodine atoms into polysulfide molecules that do not inherently possess anti-mold properties, resulting in anti-mold polysulfide molecules, i.e., anti-mold polysulfides. When added to sealants, during the curing stage, both the anti-mold polysulfide and the ordinary polysulfide matrix (the main component of the sealant) react with the curing agent to form a cross-linked network structure. The anti-mold polysulfide is integrated into this cross-linked network structure through reaction with the curing agent, preventing organic matter (such as fuel oil) from extracting it from the sealant during long-term use, thus avoiding loss of its anti-mold effect. Furthermore, the anti-mold polysulfide of this application disperses well in the sealant and is highly compatible with the polysulfide matrix during long-term use. Therefore, the anti-mold polysulfide of this application achieves a long-term anti-mold effect with an anti-mold rating of 0.

[0011] In some embodiments, the anti-mildew polysulfide is an anti-mildew polysulfide with thiol-terminated ends.

[0012] In some embodiments, the anti-mildew functional group has the following structure: in It indicates the bond between the group and other groups.

[0013] Preferably, the anti-mildew polysulfide has the following structural formula:

[0014]

[0015] in,

[0016] R1 is C1-C 12 Alkyl, preferably methyl, ethyl, propyl or butyl;

[0017] R2 has one of the following structures:

[0018]

[0019] in It indicates the bond between the group and other groups.

[0020] More preferably, the anti-mildew polysulfide has the following structural formula: Its molecular weight is 645.7 g / mol.

[0021] Secondly, the present invention provides a method for preparing the above-mentioned anti-mildew polysulfide, comprising the following steps:

[0022] In the presence of an initiator, a compound containing at least two mercapto groups is subjected to an addition reaction with a 3-iodo-2-propynyl alkyl carbamate to obtain an antifungal polysulfide.

[0023] In some embodiments, the number of thiol groups may be 2-4, for example, 2, 3 or 4. Preferably, the number of thiol groups is 2.

[0024] Preferably, the thiol group is a terminal thiol group. Two terminal thiol groups are respectively attached to carbon atoms at both ends of the molecular chain of the compound.

[0025] Preferably, the compound containing at least two thiol groups includes one or more of 1,8-dimercapto-3,6-dioxaoctane, bis(2-mercaptoethyl) ether, 2,3-dimercaptobutane, 1,3-propanedithiol, and 4,4'-dimercaptodiphenyl ether.

[0026] In some embodiments, the 3-iodo-2-propynyl alkyl carbamate is a 3-iodo-2-propynyl C1-C 12 Alkyl carbamate. "C1-C" 12 "Alkyl" refers to a straight-chain or branched alkyl group having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, or dodecyl.

[0027] Preferably, the 3-iodo-2-propynyl alkyl carbamate includes one or more of 3-iodo-2-propynyl butyl carbamate, 3-iodo-2-propynyl methyl carbamate, 3-iodo-2-propynyl ethyl carbamate, and 3-iodo-2-propynyl propyl carbamate. More preferably, the 3-iodo-2-propynyl alkyl carbamate includes 3-iodo-2-propynyl butyl carbamate.

[0028] In some embodiments, the addition reaction route is as follows:

[0029]

[0030] in,

[0031] R1 is C1-C 12 Alkyl, preferably methyl, ethyl, propyl or butyl;

[0032] R2 has one of the following structures:

[0033]

[0034] in It indicates the bond between the group and other groups.

[0035] In some specific embodiments, the addition reaction route is as follows:

[0036]

[0037] In some embodiments, the molar ratio of the compound containing at least two thiol groups to the 3-iodo-2-propynyl alkyl carbamate may be (1.8-2.2):1, for example, 1.8:1, 1.9:1, 2.0:1, 2.1:1 or 2.2:1.

[0038] In some embodiments, the temperature of the addition reaction can be 60-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C. The time of the addition reaction can be 7-9 hours, for example, 7 hours, 7.5 hours, 8 hours, 8.5 hours or 9 hours.

[0039] In some embodiments, the initiator includes one or more of azobisisovalerate (AMBN), azobisisoheptanenitrile (ABVN), azobisisobutyronitrile (AIBN), and dimethyl azobisisobutyrate (AIBME).

[0040] In this invention, after a compound containing at least two thiol groups undergoes an addition reaction with 3-iodo-2-propynyl alkyl carbamate, the thiol content decreases significantly, thus demonstrating that the compound did indeed undergo an addition reaction with 3-iodo-2-propynyl alkyl carbamate, consuming the thiol groups. In this invention, the thiol content refers to the ratio of the weight of thiol groups to the weight of the product (the antifungal polysulfide with thiol-terminated ends).

[0041] Thirdly, the present invention provides an anti-mildew sealant comprising separately packaged component A and component B;

[0042] Component A is a base paste, which includes a polysulfide matrix, anti-mildew polysulfide, filler and catalyst, wherein the anti-mildew polysulfide is the anti-mildew polysulfide of the first aspect of the present invention or the anti-mildew polysulfide obtained by the preparation method of the second aspect of the present invention.

[0043] Component B is a curing agent.

[0044] In some embodiments, the polysulfide matrix is ​​a mercapto-terminated liquid polysulfide rubber with the molecular formula: HS-R1-S-[CH2-CH(R2)-S-R1-S] n -H, where R1 = -[(-CH2-)] a -O-] b -(CH2) c -; a=1~6; b=1~6; c=1~8; R2=-R3-SH; R3=C 3-10Branched n-alkylene groups; n is a positive integer from 1 to 50, the number average molecular weight is from 2000 to 6000, and the thiol content is from 1.5% to 3%. The thiol content can be determined by titration.

[0045] In some embodiments, the filler may include one or more of calcium carbonate, bentonite, titanium dioxide, kaolin, fumed silica, and precipitated silica.

[0046] In some embodiments, the catalyst may include one or more organic tertiary amines. For example, the catalyst may be triethylenediamine.

[0047] In some embodiments, the curing agent may be an epoxy resin curing agent. The epoxy resin curing agent may include one or more bisphenol A type epoxy resins such as E44, E51, and F44.

[0048] In some embodiments, the weight ratio of the polysulfide matrix to the anti-mildew polysulfide is 100:(1-5), for example, it can be 100:1, 100:2, 100:3, 100:4 or 100:5.

[0049] In some embodiments, the weight ratio of the polysulfide matrix to the filler may be 100:(5-30), for example, 100:5, 100:10, 100:15, 100:20, 100:25 or 100:30.

[0050] In some embodiments, the weight ratio of the polysulfide matrix to the catalyst may be 100:(0.1-1), for example, 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9 or 100:1.

[0051] In some embodiments, the weight ratio of the base paste to the curing agent may be 100:(6-8), for example, 100:6, 100:6.5, 100:7, 100:7.5, or 100:8. By controlling the weight ratio of the base paste to the curing agent, it is beneficial to form a better elastomer and improve sealing and anti-mildew properties.

[0052] When using the anti-mildew sealant of the present invention, the base paste and the curing agent can be mixed evenly according to the above weight ratio, and then the sealant can be cured under the conditions of temperature 20-30℃ and humidity 40%-60%.

[0053] In some embodiments, the base paste and the curing agent are mixed in the above weight ratio and stirred evenly within half an hour.

[0054] In some embodiments, the curing temperature may be 21°C, 22°C, 23°C, 24°C, or 25°C. The humidity may be 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55%.

[0055] By controlling the curing temperature and humidity, the cross-linking curing time can be controlled within 1 to 12 hours, thereby effectively providing the uniformity of the cross-linking network, improving the toughness and strength of the sealant, and ensuring good resistance to mold.

[0056] If the curing temperature and humidity are not within the above-mentioned range, it will have an uncontrollable impact on the cross-linking curing, thereby affecting the curing time and adversely affecting the cross-linking results, reducing the toughness and strength of the sealant, and adversely affecting the sealant's anti-mildew properties. Attached Figure Description

[0057] Figure 1 This is a diagram illustrating the long-term anti-mold effect of the anti-mold sealant in Example 1-1.

[0058] Figure 2 This is a diagram illustrating the long-term anti-mold effect of the anti-mold sealant in Example 2-1.

[0059] Figure 3 This is a diagram illustrating the long-term anti-mold effect of the anti-mold sealant in Comparative Example 1-1.

[0060] Figure 4 This is a diagram illustrating the long-term anti-mold effect of the anti-mold sealant in Comparative Example 2.

[0061] Figure 5 The NMR spectrum of the antifungal polysulfide with thiol-terminated capping prepared in Example 1 is shown. Detailed Implementation

[0062] The technical solution of the present invention will be further described in detail below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0063] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or through existing methods; unless otherwise specified, the amounts of experimental reagents used are the amounts used in conventional experimental operations; unless otherwise specified, the experimental methods are all conventional methods.

[0064] This invention aims to provide a polysulfide with anti-mildew properties. Sealant made using this anti-mildew polysulfide can be given effective anti-mildew functionality.

[0065] Preparation of anti-mildew polysulfide

[0066] Example 1

[0067] Nitrogen gas was bubbled into a round-bottom flask, and 14.56 g (0.08 mol) of 1,8-dimercapto-3,6-dioxaoctane and 11.1 g (0.04 mol) of 3-iodo-2-propynyl butylcarbamate (IPBC) were added. The mixture was stirred thoroughly at room temperature, then heated to 70 °C, and 15 mg of the initiator azobisisovalerate was added. The reaction mixture was maintained at 70 °C for 8 h to generate a thiol-terminated antifungal polysulfide. The NMR spectrum is shown below. Figure 5 As shown in the figure. The thiol content of the product was determined by titration, and the final thiol content was determined to be 8.5%.

[0068] Example 2

[0069] A thiol-terminated antifungal polysulfide was prepared according to the method described in Example 1, except that 11.1 g (0.04 mol) of 3-iodo-2-propynyl butylcarbamate was replaced with 10.9 g (0.04 mol) of 3-iodo-2-propynyl methylcarbamate. The thiol content of the product was determined by titration, and the final thiol content was determined to be 8.5%.

[0070] Example 3

[0071] The antifungal polysulfide with thiol-terminated ends was prepared according to the method described in Example 1, except that 13.10 g (0.072 mol) of 1,8-dimercapto-3,6-dioxane was used.

[0072] Example 4

[0073] The antifungal polysulfide with thiol-terminated ends was prepared according to the method described in Example 1, except that 16.02 g (0.088 mol) of 1,8-dimercapto-3,6-dioxane was used.

[0074] Example 5

[0075] The antifungal polysulfide with thiol-terminated ends was prepared according to the method described in Example 1, except that the reaction mixture was kept at 60°C for 9 hours.

[0076] Example 6

[0077] The antifungal polysulfide with thiol-terminated ends was prepared according to the method described in Example 1, except that the reaction mixture was kept at 80°C for 7 hours.

[0078] Comparative Example 1

[0079] Nitrogen gas was bubbled into a round-bottom flask, and 14.56 g of 1,8-dimercapto-3,6-dioxaoctane and 6.2 g (0.04 mol) of 2-benzisothiazolin-3-one (BIT) were added. The mixture was stirred thoroughly at room temperature, then heated to 70 °C, and 15 mg of the initiator azobisisovalerate was added. The mixture was maintained at 70 °C for 8 h to obtain the product (2-benzisothiazolin-3-one is a conventional antifungal agent and does not undergo an addition reaction with 1,8-dimercapto-3,6-dioxaoctane). The thiol content of the product was determined by titration, and the final thiol content was determined to be 14.7%.

[0080] Preparation of anti-mildew sealant

[0081] Example 1-1

[0082] Weigh 100g of polysulfide raw rubber, add 10g of calcium carbonate and 20g of kaolin, mix well, then add 0.5g of triethylenediamine as a catalyst, and add 1.37g of the anti-mildew polysulfide synthesized in Example 1, mix well to prepare a base paste. Separately package the base paste and the curing agent epoxy resin E44 at a ratio of 100:6.5 to obtain the anti-mildew sealant.

[0083] Examples 1-2

[0084] The anti-mildew sealant was prepared according to the method described in Example 1-1, except that 1g of the anti-mildew polysulfide synthesized in Example 1 was added.

[0085] Examples 1-3

[0086] The anti-mildew sealant was prepared according to the method described in Example 1-1, except that 5g of the anti-mildew polysulfide synthesized in Example 1 was added.

[0087] Example 2-1

[0088] The anti-mildew sealant was prepared according to the method described in Examples 1-1, except that the anti-mildew polysulfide synthesized in Example 2 was used instead of the anti-mildew polysulfide synthesized in Example 1.

[0089] Example 3-1

[0090] The anti-mildew sealant was prepared according to the method described in Examples 1-1, except that the anti-mildew polysulfide synthesized in Example 3 was used instead of the anti-mildew polysulfide synthesized in Example 1.

[0091] Example 4-1

[0092] The anti-mildew sealant was prepared according to the method described in Examples 1-1, except that the anti-mildew polysulfide synthesized in Example 4 was used instead of the anti-mildew polysulfide synthesized in Example 1.

[0093] Example 5-1

[0094] The anti-mildew sealant was prepared according to the method described in Examples 1-1, except that the anti-mildew polysulfide synthesized in Example 5 was used instead of the anti-mildew polysulfide synthesized in Example 1.

[0095] Example 6-1

[0096] The anti-mildew sealant was prepared according to the method described in Examples 1-1, except that the anti-mildew polysulfide synthesized in Example 6 was used instead of the anti-mildew polysulfide synthesized in Example 1.

[0097] Comparative Example 1-1

[0098] The anti-mildew sealant was prepared according to the method described in Examples 1-1, except that the product synthesized in Comparative Example 1 was used instead of the anti-mildew polysulfide synthesized in Example 1.

[0099] Comparative Example 2

[0100] The anti-mildew sealant was prepared according to the method described in Example 1-1, except that no anti-mildew polysulfide was added to the base paste.

[0101] Comparative Example 3

[0102] Weigh 100g of polysulfide raw rubber, add 10g of calcium carbonate and 20g of kaolin, mix well, then add 0.5g of triethylenediamine as a catalyst, and add 1.37g of 2-benzisothiazolin-3-one (BIT), mix well to prepare a base paste. Separately package the base paste and the curing agent epoxy resin E44 at a ratio of 100:6.5 to obtain an anti-mildew sealant.

[0103] Performance testing

[0104] The curing agent and base paste, packaged separately in the anti-mold sealant, were mixed evenly. The sealant was cured in a mold at 23°C and 50% humidity. After immersion in No. 3 aviation kerosene at 69°C for 14 days, the long-term anti-mold rating of the sealant was tested. Specific test results are shown in the table below. Figure 1-4 As shown, Figure 1-4 The results were obtained using a mold test chamber and tested according to the rubber anti-mold performance test method HG / T 4301-2012.

[0105] Table 1

[0106] serial number Long-term mildew resistance Long-term anti-mildew effect Example 1-1 Level 0 like Figure 1 As shown Examples 1-2 Level 0 / Examples 1-3 Level 0 / Example 2-1 Level 0 like Figure 2 As shown Example 3-1 Level 0 / Example 4-1 Level 0 / Example 5-1 Level 0 / Example 6-1 Level 0 / Comparative Example 1-1 Level 4 like Figure 3 As shown Comparative Example 2 Level 4 like Figure 4 As shown Comparative Example 3 Level 4 /

[0107] By comparing the embodiments and comparative examples, it can be seen that the anti-mildew sealant of this application has a long-term effective anti-mildew function.

[0108] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A mildew-resistant polysulfide, characterized in that, The anti-mildew polysulfide has the following structural formula: ， in, R1 is methyl, ethyl, propyl, or butyl; R2 has the following structure: wherein represents a bond to the other group.

2. The mildew-proof polysulfide according to claim 1, characterized by, The anti-mildew polysulfide has the following structural formula: 。 3. A method for producing the mildew-proof polysulfide according to claim 1 or 2, characterized by, Includes the following steps: In the presence of an initiator, 1,8-dimercapto-3,6-dioxaoctane undergoes an addition reaction with 3-iodo-2-propynyl alkyl carbamate to obtain antifungal polysulfide.

4. The production method according to claim 3, characterized by, The 3-iodo-2-propynyl alkyl carbamate is a 3-iodo-2-propynyl C1-C 12 Alkyl carbamate.

5. The preparation method according to claim 4, characterized in that, The 3-iodo-2-propynyl alkyl carbamate includes one or more of 3-iodo-2-propynyl butyl carbamate, 3-iodo-2-propynyl methyl carbamate, 3-iodo-2-propynyl ethyl carbamate, and 3-iodo-2-propynyl propyl carbamate.

6. The preparation method according to claim 3, characterized in that, The molar ratio of 1,8-dimercapto-3,6-dioxaoctane to 3-iodo-2-propynyl alkyl carbamate is (1.8-2.2):

1.

7. The preparation method according to claim 3, characterized in that, The addition reaction is carried out at a temperature of 60-80°C for 7-9 hours.

8. The preparation method according to claim 3, characterized in that, The initiator is one or more of azobisisovalerate (AMBN), azobisisoheptanenitrile (ABVN), azobisisobutyronitrile (AIBN), and dimethyl azobisisobutyrate (AIBME).

9. A mildew resistant sealant characterized by, Includes separately packaged components A and B; Component A is a base paste, which includes a polysulfide matrix, anti-mildew polysulfide, filler and catalyst, wherein the anti-mildew polysulfide is the anti-mildew polysulfide according to claim 1 or 2 or the anti-mildew polysulfide obtained by the preparation method according to any one of claims 3-8. Component B is a curing agent.

10. The mildew resistant sealant of claim 9, wherein The weight ratio of the polysulfide matrix to the anti-mildew polysulfide is 100:(1-5).

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