Flame-retardant cyanoacrylate adhesive

Abstract

The present application relates to the technical field of cyano acrylate adhesive, and particularly discloses a flame-retardant cyano acrylate adhesive. The flame-retardant cyano acrylate adhesive comprises component A and component B; the component A comprises cyano acrylate and reinforcing aids; the component B comprises flame retardants and other aids; and the reinforcing aids are hydroxy acrylate compounds or hydroxy methacrylate compounds. The cyano acrylate adhesive provided by the present application not only has high strength and toughness, good machinability, but also has excellent flame retardancy, greatly improving the safety of cyano acrylate adhesive application, and has small volume shrinkage after curing, and is suitable for bonding porous materials or parts with large gaps and complex shapes. The cyano acrylate adhesive has very important significance for expanding the application field of cyano acrylate and has extremely high popularization and application value.

Description

Technical Field

[0001] This invention relates to the field of cyanoacrylate adhesives, and more particularly to a flame-retardant cyanoacrylate adhesive. Background Technology

[0002] Cyanoacrylate adhesives, also known as instant adhesives, are a type of single-component, fast-curing adhesive. They have advantages such as rapid curing at room temperature, wide range of bonding materials, low viscosity, and thin adhesive layer, and have been widely used in electronics, machinery, medical and wood industries.

[0003] Because cyanoacrylate adhesives are brittle after curing and have poor machinability, they are rarely used in engineering applications. In recent years, research into expanding the applications of cyanoacrylate adhesives has increased and made significant progress. For example, Bostik has launched two-component structural adhesives with high strength and hardness, as well as two-component structural adhesives with high elasticity and toughness, suitable for conventional machining and engineering caulking. Henkel has also been researching ways to improve the strength, toughness, and resistance to damp heat of these adhesives. However, there are no reports on flame-retardant cyanoacrylate adhesives, limiting the further expansion of their applications. Summary of the Invention

[0004] In view of this, the present invention provides a flame-retardant cyanoacrylate adhesive.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0006] A flame-retardant cyanoacrylate adhesive, comprising component A and component B;

[0007] Component A includes cyanoacrylate and reinforcing agents;

[0008] Component B includes flame retardants and other additives;

[0009] The reinforcing agent is a hydroxy acrylate compound or a hydroxy methacrylate compound.

[0010] In this invention, the adhesives mentioned above mainly refer to α-cyanoacrylate adhesives, especially α-cyanoacrylate low alkyl ester adhesives.

[0011] The polymerization mechanism of cyanoacrylate adhesives is anionic polymerization and free radical polymerization. The challenges in improving flame retardant performance in this system include: 1. Inorganic solid flame retardants have better flame retardant effects than organic flame retardants. However, inorganic solid flame retardants have poor dispersibility in cyanoacrylate systems. Since inorganic solid flame retardants are generally neutral or slightly alkaline inorganic substances, directly adding these flame retardants to cyanoacrylate systems can cause localized agglomeration, affecting the normal use of cyanoacrylate adhesives; 2. Organic flame retardants are generally liquid flame retardants. To ensure good flame retardant performance, a large amount is added, which dilutes the concentration of cyanoacrylate and reduces the strength of the system.

[0012] Through creative thinking, the inventors discovered that in a two-component cyanoacrylate system, adding hydroxyl-containing acrylate compounds or methacrylates to component A (containing cyanoacrylate) can enhance the affinity between solid flame retardants in components A and B, reduce the surface tension of the solid flame retardants, and ensure uniform dispersion of the solid flame retardants in component A, thus maximizing their flame-retardant effect. Furthermore, the selected acrylate compounds or methacrylates contain unsaturated double bonds, which can act as internal crosslinking agents, increasing the strength of the cured cyanoacrylate adhesive. This allows for the smooth integration of inorganic solid flame retardants and organic liquid flame retardants into the cyanoacrylate adhesive system. The cured adhesive also exhibits high machinability, low curing shrinkage, and high flame retardancy, significantly improving the safety of cyanoacrylate adhesive applications. This is of great significance for further expanding the application areas of cyanoacrylate adhesives.

[0013] Furthermore, component A also includes stabilizers, thickeners, and accelerators; the other additives include diluents, thixotropic agents, fillers, and initiators.

[0014] Further, component A comprises: 85-99 parts of cyanoacrylate, 5-10 parts of reinforcing agent, 0.035-0.33 parts of stabilizer, 3-15 parts of thickener and 0.01-0.2 parts of accelerator;

[0015] Component B comprises: 5-40 parts flame retardant, 50-90 parts diluent, 3-5 parts thixotropic agent, 2-6 parts filler, and 0.003-0.01 parts initiator.

[0016] Furthermore, the reinforcing agent is hydroxyethyl acrylate or hydroxyethyl methacrylate.

[0017] The selected reinforcing additives can improve the dispersion uniformity of inorganic flame retardants in the cyanoacrylate system, thereby fully leveraging the flame-retardant effect of the inorganic flame retardants. At the same time, they can also compensate for the strength reduction problem caused by the addition of liquid flame retardants to the cyanoacrylate system. As a result, the prepared cyanoacrylate adhesives not only have high strength and toughness, but also high flame retardancy, which can effectively expand the application fields of cyanoacrylate adhesives and is of great significance for improving the market competitiveness of products.

[0018] Preferably, the stabilizer comprises 0.005-0.03 parts of anionic stabilizer and 0.03-0.3 parts of free radical stabilizer.

[0019] Preferably, the anionic stabilizer is at least one of methanesulfonic acid, p-toluenesulfonic acid, boron trifluoride diethyl ether complex, boron fluoride, sulfur dioxide, or citric acid.

[0020] Preferably, the free radical stabilizer is at least one of 4-methoxyphenol, hydroquinone, or hydroxyanisole.

[0021] More preferably, the stabilizer comprises: 0.001-0.002 parts of boron trifluoride diethyl ether complex, 0.004-0.01 parts of boron fluoride, and 0.03-0.3 parts of 4-methoxyphenol.

[0022] Preferred stabilizers can improve the storage stability of cyanoacrylate adhesives.

[0023] Preferably, the thickener is one or both of polymethyl methacrylate or acrylate rubber.

[0024] Preferred thickeners can increase the viscosity of cyanoacrylate adhesives, which is beneficial for bonding porous materials or parts with large gaps and complex shapes. They can also improve the strength of cyanoacrylate adhesives to a certain extent.

[0025] Preferably, the accelerator is one or both of 18-crown-6-ether or dibenzo-18-crown-6-ether.

[0026] Preferred accelerators can speed up the curing of adhesives without affecting their storage stability.

[0027] It should be noted that other additives such as antioxidants, pigments, colorants, and toughening agents may also be added to component A.

[0028] Preferably, the diluent is triacetin.

[0029] It should be noted that the flame retardant described in this invention may be an inorganic solid flame retardant or an organic flame retardant.

[0030] Preferably, the flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, alkyl phosphate esters, or aliphatic halogenated hydrocarbons.

[0031] Furthermore, the inorganic flame retardant is nano-magnesium hydroxide, and the organic flame retardant is tricresyl phosphate.

[0032] Preferably, the nano-magnesium hydroxide has a particle size of 40nm-60nm, which is beneficial to improving its dispersion uniformity in cyanoacrylate adhesive systems.

[0033] For example, if an inorganic flame retardant is chosen, the amount added is 5-10 parts; if an organic liquid flame retardant is chosen, the amount added is 30-40 parts.

[0034] Preferably, the thixotropic agent is hydrophobic silicon dioxide.

[0035] Preferably, the filler is hydrated calcium silicate.

[0036] The hydrated calcium silicate consists of spherical porous particles with an average particle size of 35μm-65μm. Adding hydrated calcium silicate reduces the volume shrinkage of cyanoacrylate adhesives during curing, making them more convenient for repairing pits, cracks, or holes.

[0037] Preferably, the initiator is at least one of N,N-dimethyl-p-toluidine, 5-chloro-2-methylbenzothiazole, or dibutyltin dilaurate.

[0038] Preferably, the cyanoacrylate is at least one of the compounds shown in Formula 1.

[0039]

[0040] Wherein, R is a C1-C8 alkyl, C3-C5 alkoxyethyl, C4-C8 cycloalkyl, or C7-C10 aryl.

[0041] More preferably, R is ethyl, methoxyethyl, or ethoxyethyl.

[0042] More preferably, R is ethyl.

[0043] The aforementioned cyanoacrylates can be prepared by methods well known to those skilled in the art, such as the method described in patent US2467927, or commercially available raw materials can be used directly.

[0044] The preparation method of the flame-retardant cyanoacrylate adhesive described in this invention is as follows: after mixing the raw materials of component A and component B in proportion, stir at room temperature until the solid is completely dissolved. If it contains a tackifier, the temperature can be appropriately increased and stirred until the mixture is uniform.

[0045] For example, the preparation method of component A includes the following steps: mixing cyanoacrylate with stabilizer, accelerator and reinforcing agent, stirring until the solid material is dissolved, heating to 60℃-70℃, slowly adding thickener under stirring, mixing evenly, cooling down to obtain component A.

[0046] The preparation method of component B includes the following steps: adding flame retardant, diluent, thixotropic agent, filler and initiator into a container, shearing and emulsifying to obtain component B.

[0047] When using, simply mix component A and component B at a mass ratio of 3:1 until homogeneous.

[0048] The cyanoacrylate adhesive provided by this invention not only has high strength and toughness and good machinability, but also excellent flame retardancy and low volume shrinkage after curing. It is suitable for bonding porous materials or parts with large gaps and complex shapes, and has higher application safety. It is of great significance for expanding the application field of cyanoacrylate and has extremely high promotion and application value. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0050] To better illustrate the present invention, further examples are provided below.

[0051] Example

[0052] This invention provides a flame-retardant cyanoacrylate adhesive, comprising component A and component B, wherein the raw material composition of component A is shown in the table below:

[0053]

[0054]

[0055] The raw material composition of component B is shown in the table below:

[0056] Component B1 share Component B2 share Component B3 share Nano magnesium hydroxide 5 Aluminum hydroxide 10 Trimethyl phosphate 40 Triacetylglycerol 82 Triacetylglycerol 90 Triacetylglycerol 50 Hydrophobic silica 4 Hydrophobic silica 3 Hydrophobic silica 5 hydrated calcium silicate 6 hydrated calcium silicate 2 hydrated calcium silicate 3 N,N-Dimethyl-p-toluidine 0.003 5-Chloro-2-methylbenzothiazole 0.01 Dibutyltin dilaurate 0.005

[0057] The preparation method of the above-mentioned flame-retardant cyanoacrylate adhesive includes the following steps:

[0058] Preparation of component A: Mix cyanoacrylate with stabilizer, accelerator and reinforcing agent, stir until solid material is dissolved, heat to 60℃-70℃, slowly add thickener under stirring, and after the thickener is completely dissolved, cool down to obtain component A;

[0059] Preparation of component B: Flame retardant, diluent, thixotropic agent, filler and initiator are added to a container and dispersed at room temperature using a high-shear emulsifying dispersant for 1 hour intermittently to obtain component B.

[0060] Comparative Example

[0061] This comparative example provides a cyanoacrylate adhesive, comprising component A and component B, wherein the raw material composition of component A is shown in the table below:

[0062]

[0063]

[0064] The raw material composition of component B is shown in the table below:

[0065]

[0066] The preparation method of the above-mentioned cyanoacrylate adhesive is the same as that in the examples, and will not be repeated here.

[0067] Compared with the above comparative examples, the embodiments have the following differences:

[0068] Comparative Example a1 has no reinforcing additives compared to Example A1;

[0069] Compared to Example A1, Comparative Example a2 uses an acrylate material that does not contain hydroxyl groups;

[0070] Comparative Example b1 contains no flame retardant compared to Example B1;

[0071] Comparative Example b2 contains no filler compared to Example B1;

[0072] Comparative Example b3 contains no flame retardant compared to Example B2;

[0073] Comparative Example b4 contains no filler compared to Example B2;

[0074] Comparative Example b5 contains no flame retardant or filler compared to Example 1.

[0075] Performance testing

[0076] Before testing, component A and component B were mixed evenly at a mass ratio of 3:1 to obtain cyanoacrylate adhesive.

[0077] Performance testing includes:

[0078] Tensile strength: Tested according to GB 7124-1986, the method for determining the tensile shear strength of adhesives (metal to metal);

[0079] Flammability: Tested according to UL-94 vertical flammability test standard;

[0080] Elongation at break: Tested in accordance with GB / T 528-1998 standard for determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber;

[0081] Appearance: Visually inspect the adhesive for any obvious shrinkage after curing.

[0082] The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085] Note: V1 - indicates that the flammability is between HB and V1.

[0086] The comparative examples a1-B1, a1-B2, a2-B1, and a2-B2 show that the flame retardant was unevenly dispersed and agglomerated after mixing components A and B, making it impossible to conduct tensile strength, elongation at break, and flame retardancy tests.

[0087] Replacing the flame retardant, anionic stabilizer, and free radical stabilizer in the embodiments with other substances defined in this invention can achieve technical effects that are substantially equivalent to those in the corresponding embodiments.

[0088] In summary, the cyanoacrylate adhesive prepared by this invention can not only effectively improve the flame retardancy of cyanoacrylate adhesives, but also ensure that cyanoacrylate adhesives have the advantages of high strength, high toughness, and low shrinkage after curing. Moreover, the production cost is low, the preparation process is simple, and there are no special requirements for the application environment. This effectively expands the application field of cyanoacrylate adhesives and has broad application prospects.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flame-retardant cyanoacrylate adhesive, characterized by, consisting of component A and component B; wherein the component A is: cyano acrylate 85-99 parts, reinforcing aid 5-10 parts, stabilizer 0.035-0.33 parts, thickening agent 3-15 parts and speed-up agent 0.01-0.2 parts; the component B is: flame retardant 5-40 parts, diluent 50-90 parts, thixotropic agent 3-5 parts, filler 2-6 parts and initiator 0.003-0.01 parts; the reinforcing aid is hydroxy acrylate compound or hydroxy methacrylate compound.

2. The flame retardant cyanoacrylate adhesive of claim 1, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant effect and a high adhesive strength. the reinforcing aid is hydroxy ethyl acrylate or hydroxy ethyl methacrylate.

3. The flame retardant cyanoacrylate adhesive of claim 1, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant effect of 5 mm or less in a vertical flame test according to UL 94. the stabilizer consists of 0.005-0.03 parts of anionic stabilizer and 0.03-0.3 parts of free radical stabilizer.

4. The flame retardant cyanoacrylate adhesive of claim 3, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant effect of 5 mm or less in a vertical flame test according to UL 94. the anionic stabilizer is at least one of methyl sulfonic acid, p-toluene sulfonic acid, boron trifluoride diethyl ether complex, boron fluoride, sulfur dioxide or citric acid; and / or the free radical stabilizer is at least one of 4-methoxy phenol, hydroquinone or hydroxy anisyl butyl ether.

5. The flame retardant cyanoacrylate adhesive of claim 4, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant additive of 0.1 to 5 wt% of the total weight of the cyanoacrylate adhesive. the stabilizer is: boron trifluoride diethyl ether complex 0.001-0.002 parts, boron fluoride 0.004-0.01 parts, 4-methoxy phenol 0.03-0.3 parts.

6. The flame retardant cyanoacrylate adhesive of claim 1, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant additive. the thickening agent is one or both of polymethyl methacrylate or acrylate rubber; and / or the speed-up agent is one or both of 18-crown-6-ether or dibenzo-18-crown-6-ether.

7. The flame retardant cyanoacrylate adhesive of claim 1, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant additive. the diluent is glyceryl triacetate; and / or the flame retardant is at least one of aluminum hydroxide, magnesium hydroxide, alkyl phosphate compound or aliphatic halogenated hydrocarbon compound; and / or the thixotropic agent is hydrophobic silicon dioxide; and / or the filler is hydrated calcium silicate; and / or the initiator is at least one of N,N-dimethyl-p-toluidine, 5-chloro-2-methyl benzothiazole or dibutyl tin dilaurate.

8. The flame retardant cyanoacrylate adhesive of claim 1, wherein the flame retardant cyanoacrylate adhesive is a flame retardant cyanoacrylate adhesive having a flame retardant additive of a phosphorus compound. the cyano acrylate is at least one of the compounds shown in formula 1, formula 1 wherein R3 is C1-C8 alkyl, C3-C5 alkoxy ethyl, C4-C8 cycloalkyl or C7-C10 aralkyl.

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