A halogen-free flame-retardant organic silicone adhesive and a preparation method thereof

Abstract

The technical field of organic silicone adhesives of the present invention specifically relates to a halogen-free flame retardant organic silicone adhesive and a preparation method thereof. The halogen-free flame retardant organic silicone adhesive comprises, by weight, 150 to 200 parts of halogen-free silicone rubber; 10 to 15 parts of flame retardant; 4 to 8 parts of glass microbeads; 8 to 12 parts of surfactant; 20 to 30 parts of silane cross-linking agent; 10 to 20 parts of thickener; and 1 to 5 parts of coupling agent. The halogen-free flame retardant organic silicone adhesive of the present invention has a good flame retardant effect, and the flame retardant effect of the halogen-free flame retardant organic silicone adhesive is significantly improved by the use of a combined flame retardant. The halogen-free flame retardant organic silicone adhesive of the present application has a good flame retardant effect and a high bonding strength, and exhibits good high temperature resistance.

Description

Technical Field

[0001] The invention relates to the technical field of organic silicone adhesives, and in particular to a halogen-free flame-retardant organic silicone adhesive and a preparation method thereof. Background Art

[0002] Organic silicone adhesive is an adhesive made of organic silicon compounds, which has excellent properties such as heat resistance, weather resistance, and chemical corrosion resistance. Organic silicone adhesive is widely used in the following fields: Construction industry: used for sealing, caulking, and bonding building materials such as glass, metal, and tiles. Automobile manufacturing industry: used for sealants and adhesives in automobile assembly, as well as bonding and sealing of automobile parts. Electronics industry: used for sealing and fixing electronic products, such as the assembly of mobile phones, computers and other electronic equipment. Aerospace field: used for sealing, bonding, and waterproofing of aircraft and spacecraft.

[0003] For industries such as construction, electronic appliances, and automobile manufacturing, there are flame retardant requirements for organic silicone adhesives. In the prior art, in order to improve the flame retardant properties of organic silicone adhesives, flame retardant components are often added to the organic silicone adhesives. However, the addition of many flame retardant components will affect the bonding strength of the organic silicone adhesives, so the bonding strength and flame retardant properties of the organic silicone adhesives cannot be guaranteed at the same time. Summary of the invention

[0004] Based on the problems existing in the prior art, the present invention proposes a halogen-free flame retardant organic silicone adhesive and a preparation method thereof. The halogen-free flame retardant organic silicone adhesive provided by the present invention not only has good flame retardant properties, but also has good bonding strength and heat resistance.

[0005] Specifically, the technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, a halogen-free flame-retardant organic silicone adhesive is provided, which comprises, in parts by weight:

[0007] Halogen-free silicone rubber: 150-200 parts;

[0008] Flame retardant: 10-15 parts;

[0009] Glass beads: 4-8 parts;

[0010] Surfactant: 8-12 parts;

[0011] Silane crosslinking agent: 20-30 parts;

[0012] Thickener: 10-20 parts;

[0013] Coupling agent: 1-5 parts;

[0014] In a specific embodiment, the flame retardant includes dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate, wherein the ratio of dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate is 1:1-2:0.5-1:0.5-1.

[0015] The flame retardant selected in the present invention plays a role on different flame retardant paths, forms a coordinated flame retardant effect, dimethyl methylphosphonate can prevent the progress of the combustion chain reaction, effectively improves the flame retardant property of the material, and melamine can release nitrogen at high temperature, form an inert atmosphere, and slow down the burning speed. Melamine then releases nitrogen when burning, dilutes oxygen, slows down the burning speed, and can also generate inert nitrogen compounds at high temperature, form a carbonization layer, isolate heat and oxygen, reduce the temperature of combustion, dimethyl methylphosphonate and melamine cooperate with each other, form a more effective flame retardant barrier, further improve flame retardant property on this basis, add aluminum hydroxide and zinc borate to cooperate with dimethyl methylphosphonate and melamine, form an inorganic expansion layer at high temperature, combustibles are diluted, the volatilization of volatile combustibles can also be prevented, and smoke is reduced while further playing a flame retardant effect, so, the coordination between dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate can improve the flame retardant property of the material, making the material safer and more reliable.

[0016] In a specific embodiment, the surfactant is selected from one or both of sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS).

[0017] In a specific embodiment, the thickener is selected from one or both of polyvinyl alcohol and polymethacrylate.

[0018] When a lot of flame retardants are added to the halogen-free flame retardant organic silicone adhesive, the addition of the flame retardant will affect the bonding strength of the organic silicone adhesive. In order to solve this problem, in the present application, glass beads, surfactants and thickeners are added to jointly improve the bonding strength of the organic silicone adhesive, reduce the effect of the addition of flame retardants on the bonding strength of the organic silicone adhesive and further improve the bonding strength of the organic silicone adhesive, wherein the thickener can increase the viscosity of the adhesive and improve the bonding strength, the glass beads can increase the surface roughness of the organic silicone adhesive and improve the bonding strength, and the surfactant is selected from one or both of sodium dodecylbenzene sulfonate and sodium dodecyl sulfate, which can improve the wettability of the organic silicone adhesive with the surface and improve the bonding strength. Moreover, the glass beads, surfactants and thickeners are indispensable, and combined with the silane cross-linking agent and the coupling agent, they can jointly offset the negative effect of the addition of flame retardants on the bonding strength of the organic silicone adhesive and improve the bonding strength of the organic silicone adhesive.

[0019] In a specific embodiment, the silane crosslinking agent is selected from one or both of methyltriacetoxysilane and ethyltriacetoxysilane.

[0020] In a specific embodiment, the coupling agent is selected from one or more of 3-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane and methacryloxypropyltrimethoxysilane.

[0021] The coupling agent selected in the present invention can react with the hydroxyl group in the organic silicone adhesive to form a siloxane bond, thereby enhancing the bonding performance. The cross-linking agent selected can enhance the network structure of the organic silicone adhesive and improve its bonding performance.

[0022] Preferably, the halogen-free silicone rubber is methyl vinyl silicone rubber, wherein the vinyl content is 0.01% to 1% and the molecular weight is 600,000 to 700,000;

[0023] In a specific embodiment, the halogen-free flame retardant organic silicone adhesive comprises, in parts by weight:

[0024] Halogen-free silicone rubber: 150 parts;

[0025] Flame retardant: 10 parts;

[0026] Glass beads: 4 parts;

[0027] Surfactant: 8 parts;

[0028] Silane crosslinking agent: 20 parts;

[0029] Thickener: 10 parts;

[0030] Coupling agent: 1 part.

[0031] In a specific embodiment, the halogen-free flame retardant organic silicone adhesive comprises, in parts by weight:

[0032] Halogen-free silicone rubber: 200 parts;

[0033] Flame retardant: 15 parts;

[0034] Glass beads: 8 parts;

[0035] Surfactant: 12 parts;

[0036] Silane crosslinking agent: 30 parts;

[0037] Thickener: 20 parts;

[0038] Coupling agent: 5 parts.

[0039] In a second aspect of the present invention, a method for preparing the halogen-free flame-retardant organic silicone adhesive according to the first aspect is provided, comprising:

[0040] (1) Blending and kneading halogen-free silicone rubber, glass microbeads, a thickener and a surfactant to prepare a base material;

[0041] (2) Add the silane crosslinking agent, flame retardant and coupling agent to the base material prepared above, mix well, and obtain the product.

[0042] In a specific embodiment, in step (1), the temperature of the blending and kneading is 100-150° C., the vacuum degree is 0.08-0.10 MPa, and the time is 120-240 min.

[0043] In a specific embodiment, in step (2), the uniform mixing is performed by stirring at 200 to 600 rpm for 180 to 480 min.

[0044] In a third aspect of the present invention, there is provided a use of the halogen-free flame-retardant organic silicone adhesive described in the first aspect in the construction, electronic appliances, and automobile manufacturing industries.

[0045] The present invention has the following beneficial effects:

[0046] The halogen-free flame retardant organic silicone adhesive in the present invention has a good flame retardant effect, and the flame retardant effect of the halogen-free flame retardant organic silicone adhesive is significantly improved by using a combined flame retardant. The halogen-free flame retardant organic silicone adhesive of the present application has a good flame retardant effect and high bonding strength, and exhibits good high temperature resistance. DETAILED DESCRIPTION

[0047] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0049] The following examples are only used to illustrate the embodiments of the present invention and do not constitute any limitation to the present invention. Those skilled in the art will appreciate that various modifications may be made without departing from the spirit and scope of the present invention, and these modifications all fall within the scope of protection of the present invention.

[0050] Example 1

[0051] In this embodiment, the halogen-free flame-retardant organic silicone adhesive comprises, by weight:

[0052] Halogen-free silicone rubber: methyl vinyl silicone rubber, 150 parts, of which the vinyl content is 0.01%, and the molecular weight is 600,000;

[0053] Flame retardant: dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate: 10 parts; wherein the proportion of dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate is 1:1:0.5:0.5;

[0054] Glass beads: 4 parts;

[0055] Surfactant: sodium dodecylbenzene sulfonate, 8 parts;

[0056] Silane crosslinker: methyltriacetoxysilane, 20 parts;

[0057] Thickener: 10 parts of polymethacrylate;

[0058] Coupling agent: 3-aminopropyltrimethoxysilane, 1 part.

[0059] Preparation method:

[0060] (1) halogen-free silicone rubber, glass beads, a thickener and a surfactant are mixed and kneaded at a temperature of 100° C. and a vacuum degree of 0.08 MPa for 120 min to prepare a base material;

[0061] (2) Add the silane crosslinking agent, flame retardant and coupling agent to the base material prepared above, mix well, and obtain the product.

[0062] Example 2

[0063] In this embodiment, the halogen-free flame-retardant organic silicone adhesive comprises, by weight:

[0064] Halogen-free silicone rubber: methyl vinyl silicone rubber: 160 parts, of which the vinyl content is 0.01% and the molecular weight is 600,000;

[0065] Flame retardant: dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate: 12 parts; wherein the proportion of dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate is 1:1.5:0.6:0.6;

[0066] Glass beads: 5 parts;

[0067] Surfactant: sodium lauryl sulfate, 10 parts;

[0068] Silane crosslinker: ethyl triacetoxysilane, 25 parts;

[0069] Thickener: polyvinyl alcohol, 15 parts;

[0070] Coupling agent: γ-aminopropyltrimethoxysilane, 2 parts.

[0071] Preparation method:

[0072] (1) halogen-free silicone rubber, glass microbeads, a thickener and a surfactant are mixed and kneaded at a temperature of 120° C. and a vacuum degree of 0.09 MPa for 160 min to prepare a base material;

[0073] (2) Add the silane crosslinking agent, flame retardant and coupling agent to the base material prepared above, mix well, and obtain the product.

[0074] Example 3

[0075] In this embodiment, the halogen-free flame-retardant organic silicone adhesive comprises, by weight:

[0076] Halogen-free silicone rubber: methyl vinyl silicone rubber: 180 parts, of which the vinyl content is 0.01% and the molecular weight is 600,000;

[0077] Flame retardant: dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate: 14 parts; wherein the proportion of dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate is 1:1.8:0.8:0.8;

[0078] Glass beads: 6 parts;

[0079] Surfactant: sodium dodecylbenzene sulfonate, 10 parts;

[0080] Silane crosslinker: methyltriacetoxysilane, 28 parts;

[0081] Thickener: polyvinyl alcohol, 18 parts;

[0082] Coupling agent: methacryloxypropyltrimethoxysilane, 4 parts.

[0083] Preparation method:

[0084] (1) halogen-free silicone rubber, glass microbeads, a thickener and a surfactant are mixed and kneaded at a temperature of 140° C., a vacuum degree of 0.09 MPa, and a time of 200 min to prepare a base material;

[0085] (2) Add the silane crosslinking agent, flame retardant and coupling agent to the base material prepared above, mix well, and obtain the product.

[0086] Example 4

[0087] In this embodiment, the halogen-free flame-retardant organic silicone adhesive comprises, by weight:

[0088] Halogen-free silicone rubber: methyl vinyl silicone rubber, 200 parts, of which the vinyl content is 0.01%, and the molecular weight is 600,000;

[0089] Flame retardant: dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate: 15 parts; wherein the proportion of dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate is 1:2:1:1;

[0090] Glass beads: 8 parts;

[0091] Surfactant: sodium dodecylbenzene sulfonate, 12 parts;

[0092] Silane crosslinker: methyltriacetoxysilane, 30 parts;

[0093] Thickener: polyvinyl alcohol, 20 parts;

[0094] Coupling agent: 3-aminopropyltrimethoxysilane, 5 parts.

[0095] Preparation method:

[0096] (1) halogen-free silicone rubber, glass microbeads, a thickener and a surfactant are mixed and kneaded at a temperature of 150° C. and a vacuum degree of 0.10 MPa for 240 min to prepare a base material;

[0097] (2) Add the silane crosslinking agent, flame retardant and coupling agent to the base material prepared above, mix well, and obtain the product.

[0098] Comparative Example 1

[0099] The flame retardant is dimethyl methylphosphonate and 10 parts of melamine, and the ratio of dimethyl methylphosphonate to melamine is 1:1. The other prescription components and dosages, as well as the preparation method are the same as those in Example 1.

[0100] Comparative Example 2

[0101] The flame retardant is 10 parts of aluminum hydroxide and zinc borate, the ratio of aluminum hydroxide to zinc borate is 1:1, and the other prescription components and dosages, as well as the preparation method are the same as Example 1.

[0102] Comparative Example 3

[0103] The invention does not contain glass microspheres, and the other prescription components, dosages, and preparation methods are the same as those in Example 1.

[0104] Comparative Example 4

[0105] No surfactant is included, and the remaining prescription components and dosages, as well as the preparation method are the same as those in Example 1.

[0106] Comparative Example 5

[0107] The invention does not contain a thickener, and the other prescription components and dosages, as well as the preparation method are the same as those in Example 1.

[0108] Test example:

[0109] The performance test results of the halogen-free flame-retardant organic silicone adhesives prepared in the above Examples 1-4 and Comparative Examples 1-5 are as follows:

[0110] (1) The bonding strength of the halogen-free flame-retardant organic silicone adhesive was measured according to the standard GB / T 7124-2008; the bonding strength of the halogen-free flame-retardant organic silicone adhesive prepared in Examples 1-4 and Comparative Examples 1-5 was measured after heating at 200°C for 1 hour and after aging at 200°C, and the bonding strength of the halogen-free flame-retardant organic silicone adhesive after heating at 250°C for 1 hour and after aging at 250°C was measured; the results are shown in Table 1;

[0111] (2) The flame retardancy level of the halogen-free flame retardant silicone adhesive was tested in accordance with GB / T10707-2008. The results are shown in Table 1.

[0112] Table 1. Flame retardant grade and bonding strength of halogen-free flame retardant silicone adhesive

[0113]

[0114]

[0115] As can be seen from Table 1, the halogen-free flame retardant organic silicone adhesives prepared in Examples 1-4 exhibited better flame retardant effects, while the halogen-free flame retardant organic silicone adhesives prepared in Comparative Examples 1 and 2 had poor flame retardant effects, indicating that the flame retardant effect achieved by using only a combination of dimethyl methylphosphonate and melamine or only a combination of aluminum hydroxide and zinc borate is poor. In the embodiments of the present application, the flame retardants dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate are used in combination, which can significantly improve the flame retardant effect of the halogen-free flame retardant organic silicone adhesive. The halogen-free flame retardant organic silicone adhesives prepared in Examples 1-4 also exhibit excellent bonding strength, and after aging at 200°C and 250°C, the bonding strength of the halogen-free flame retardant organic silicone adhesives prepared in Examples 1-4 decreases less, showing good high temperature resistance, while the bonding strength of the halogen-free flame retardant organic silicone adhesives prepared in Comparative Examples 3, 4 and 5 is poorer than that of Examples 1-4, and after aging at 200°C and 250°C, the bonding strength decreases more, and the heat resistance is poor, indicating that the combination of glass beads, surfactants and thickeners can jointly improve the bonding strength of organic silicone adhesives and play a good synergistic role, and none of the three is dispensable.

[0116] In summary, the halogen-free flame-retardant organic silicone adhesive prepared by the present invention has good flame-retardant effect and bonding strength, slow aging speed and strong heat resistance.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A halogen-free flame-retardant organic silicone adhesive, characterized in that: It comprises, by weight: Halogen-free silicone rubber: 150~200 parts; Flame retardant: 10~15 parts; Glass beads: 4~8 parts; Surfactant: 8-12 parts; Silane crosslinking agent: 20-30 parts; Thickener: 10~20 parts; Coupling agent: 1~5 parts; The flame retardant comprises dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate, wherein the proportion of the dimethyl methylphosphonate, melamine, aluminum hydroxide and zinc borate is 1:1-2:0.5-1:0.5-1.

2. The halogen-free flame-retardant organic silicone adhesive according to claim 1, characterized in that: The silane crosslinking agent is selected from one or both of methyltriacetoxysilane and ethyltriacetoxysilane.

3. The halogen-free flame-retardant organic silicone adhesive according to claim 1, characterized in that: The surfactant is selected from one or both of sodium dodecylbenzene sulfonate and sodium dodecyl sulfate.

4. The halogen-free flame-retardant organic silicone adhesive according to claim 1, characterized in that: The thickener is selected from one or both of polyvinyl alcohol and polymethacrylate.

5. The halogen-free flame-retardant organic silicone adhesive according to claim 1, characterized in that: The coupling agent is selected from one or more of 3-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane and methacryloxypropyltrimethoxysilane.

6. The halogen-free flame-retardant organic silicone adhesive according to claim 1, characterized in that: The halogen-free silicone rubber is methyl vinyl silicone rubber, wherein the vinyl content is 0.01% to 1% and the molecular weight is 600,000 to 700,000.

7. A method for preparing the halogen-free flame-retardant organic silicone adhesive according to any one of claims 1 to 6, comprising the following steps: (1) Blending and kneading halogen-free silicone rubber, glass microbeads, a thickener and a surfactant to prepare a base material; (2) Add the silane crosslinking agent, flame retardant and coupling agent to the base material prepared above and mix well to obtain the product.

8. The preparation method according to claim 7, characterized in that: In step (1), the temperature of the blending and kneading is 100-150° C., the vacuum degree is 0.08-0.10 MPa, and the time is 120-240 min.

9. Application of the halogen-free flame-retardant organic silicone adhesive according to any one of claims 1 to 6 in the construction, electronic appliances, and automobile manufacturing industries.

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