Silicon-based rubber bonding method

Abstract

The invention discloses a silicon-based rubber bonding method, which is used for bonding silicon-based rubber to a substrate, and comprises the following steps: coating a bonding surface of the silicon-based rubber with isopropanol, and drying for preset time; coating adhesive glue on the adhesive surface of the silicon-based rubber, and drying until the adhesive glue is in a semi-solid state; the adhesive glue comprises ethyl cyanoacrylate and epoxy resin; bonding the bonding surface of the silicon-based rubber with the bonded surface of the substrate, applying pressure to the bonding surface of the silicon-based rubber and the bonded surface of the substrate, and keeping pressure to complete bonding of the silicon-based rubber. According to the bonding method, the problems that the bonding strength is low when the silicon-based rubber is bonded, and the softness and the rebound resilience of the bonded silicon-based rubber are reduced can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of silicone-based rubber bonding, and in particular to a silicone-based rubber bonding method. Background Art

[0002] Silicone rubber usually refers to a rubber material with silicon-oxygen bonds (—Si—O—) as the main structural unit, that is, organic silicone rubber. Due to the excellent performance of silicone rubber itself, this material is partially applied in some footwear products. Generally, the silicone rubber is fixed to the base by bonding. The base here can be the sole or upper of the footwear product. However, due to the material structure characteristics of silicone rubber itself, when bonding silicone rubber to the base, there are problems such as low bonding strength, reduced softness and resilience of silicone rubber after bonding. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology and to provide a silicone-based rubber bonding method, which can improve the problems of low bonding strength during silicone-based rubber bonding and decreased softness and resilience of the silicone-based rubber after bonding.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] Technical solution 1: A silicone-based rubber bonding method, which is used to bond the silicone-based rubber to a substrate, comprising: applying isopropyl alcohol to the bonding surface of the silicone-based rubber and drying it for a preset time; applying adhesive to the bonding surface of the silicone-based rubber and drying it until the adhesive is semi-solid; the adhesive comprises ethyl cyanoacrylate and epoxy resin; and fitting the bonding surface of the silicone-based rubber to the bonded surface of the substrate, applying and maintaining pressure on the two, and completing the bonding of the silicone-based rubber.

[0006] Technical Solution 2 based on Technical Solution 1: After brushing the adhesive surface of the silicone-based rubber with isopropyl alcohol, the preset drying period is 90s-150s in an environment of 5-35°C, and the drying time decreases as the ambient temperature rises.

[0007] Technical solution three based on technical solution two: after applying adhesive on the bonding surface of the silicone-based rubber, dry it at 5-35°C for 20-30s until the adhesive becomes semi-solid.

[0008] Technical solution 4 based on technical solution 3: the mass proportion of ethyl cyanoacrylate in the adhesive is 85%-87%, and the mass proportion of epoxy resin is 9%-11%.

[0009] Technical Solution 5 based on Technical Solution 1: After the adhesive surface of the silicone rubber is attached to the bonded surface of the substrate, the adhesive surface is bonded to the substrate at a pressure of 30-35 kg / cm 2 Apply pressure to both and maintain it for 20-25 seconds.

[0010] Technical solution 6 based on technical solution 1: before the bonded surface of the substrate is bonded to the bonding surface of the silicone camera, the bonded surface is coated with polyurethane adhesive and dried at 50-55° C. for 120-150 seconds.

[0011] Technical solution seven based on technical solution six: the polyurethane adhesive includes 5%-8% butanone, 10%-15% dimethyl carbonate, 25%-30% acetone, 20%-25% ethyl acetate, 15%-20% methyl acetate, and 14%-16% polyurethane resin in a mass ratio.

[0012] Technical solution eight based on technical solution six: the substrate is made of ethylene vinyl acetate copolymer material, and before applying the polyurethane adhesive, a reagent cleaning step and an ultraviolet irradiation treatment step are performed in sequence; the reagent cleaning step includes cleaning the bonded surface with alkaline liquid, neutral liquid, and acidic liquid in sequence; the ultraviolet irradiation treatment step includes drying the bonded surface after applying the ultraviolet irradiation treatment agent, and irradiating the bonded surface with ultraviolet light.

[0013] Technical solution nine based on technical solution eight: in the reagent cleaning step, the alkaline liquid is water with a pH range of 11-12 and a temperature of 50-55°C, the neutral liquid is water with a pH range of 7-9 and a temperature of 50-55°C, and the acidic liquid is an oxalic acid aqueous solution with a pH range of 3-4 and a temperature of 50-55°C.

[0014] Technical Solution 10 based on Technical Solution 9: In the ultraviolet irradiation treatment step, the ultraviolet irradiation treatment agent includes 25-30% by weight of butanone, 35-40% by weight of methylcyclohexane, 30-35% by weight of ethyl acetate and 3-5% by weight of polymethyl methacrylate resin; the ultraviolet irradiation energy is 0.55-0.65 J / cm 2 .

[0015] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following beneficial effects:

[0016] During the research process, the inventors found that the reason why the bonding strength is low and the softness and resilience of the silicone rubber after bonding are reduced when the silicone rubber is bonded to the substrate is that the silicone rubber itself has a low polarity, and conventional treatment agents have a poor effect on its surface treatment, which affects the bonding strength; at the same time, the silicone rubber itself has a high cross-linking density, which limits the mobility of the polymer chain segments and hinders the effective diffusion of the adhesive inside the silicone rubber material, thereby further affecting the bonding strength; at the same time, during the bonding process, conventional adhesives are also prone to destroy the structure of the silicone rubber, resulting in a decrease in its softness and resilience.

[0017] In the silicone rubber bonding method provided by the present invention, firstly, the bonding surface of the silicone rubber is brushed with isopropyl alcohol and dried for a preset time. The isopropyl alcohol can clean the bonding surface of the silicone rubber, keep the bonding surface clean, and improve the hydrophobicity of the bonding surface. The isopropyl alcohol has no swelling property on the silicone rubber, which can reduce the damage of the organic solvent to the silicone rubber, so that the silicone rubber can still maintain its physical properties after bonding. Then, an adhesive is brushed on the bonding surface of the silicone rubber and disturbed until the adhesive is semi-solid. The adhesive adopts a product including ethyl cyanoacrylate and epoxy resin, which can be cured by reacting with water. Since the hydrophobicity of the bonding surface of the silicone rubber has been improved by isopropyl alcohol, The bonding surface of the silicone-based rubber can retain more moisture, thereby improving the curing effect of the adhesive; and the ethyl cyanoacrylate mainly included in the adhesive contains highly active functional groups such as cyano and ester groups, which can interact with the microstructure of the silicone-based rubber to achieve bonding, thereby reducing the influence of the low polarity of the silicone-based rubber on the bonding strength; and the adhesive has a fast curing speed. When it is in a semi-solid state and adhered to the bonded surface of the substrate, the curing time of the adhesive between the bonding surface and the bonded surface can be reduced, thereby reducing the impact on the silicone-based rubber during the bonding process, thereby improving the overall bonding effect, and can also retain the softness and resilience of the silicone-based rubber.

[0018] In addition, polyurethane adhesive is also applied on the bonded surface of the substrate, which can form a strong intermolecular force with the substrate, and infiltrate and adhere to the substrate, thereby providing a more solid foundation for bonding with the silicone-based rubber, further improving the bonding strength of the silicone-based rubber. In addition, polyurethane adhesive has a certain degree of flexibility and elasticity after curing, and can be combined with the adhesive of silicone-based rubber to improve the softness and resilience of silicone-based rubber after bonding, and avoid cracks in silicone-based rubber when it is bent after bonding.

[0019] Among them, when the substrate is made of ethylene vinyl acetate copolymer, the polyurethane adhesive can interweave and entangle with the molecular chains on the bonded surface of the substrate to form an interpenetrating network structure, which can make the bond between the polyurethane adhesive and the substrate tighter. At the same time, when the silicone-based rubber coated with adhesive is attached to the bonded surface of the substrate, this network structure can further interact with the adhesive to form a chemical bond, thereby further enhancing the bonding strength between the silicone-based rubber and the substrate.

[0020] When the substrate is made of ethylene vinyl acetate copolymer, a reagent cleaning step and an ultraviolet irradiation treatment step are performed in sequence before applying the polyurethane adhesive. The reagent cleaning step uses alkaline liquid, neutral liquid, and acidic liquid for cleaning in sequence, which can effectively remove impurities, oil stains and other pollutants on the surface of the substrate, improve the activity and cleanliness of the substrate surface, provide good surface conditions for subsequent ultraviolet irradiation treatment and application of polyurethane adhesive, enhance the bonding force between the polyurethane adhesive and the substrate, and indirectly improve the bonding strength between the silicone-based rubber and the substrate; the ultraviolet irradiation treatment step (drying and irradiating after applying the ultraviolet irradiation treatment agent) can further activate the substrate surface, change the molecular structure of the substrate surface, increase the surface energy, and improve the chemical reaction activity between the substrate and the polyurethane adhesive, which is conducive to forming a more solid bonding interface and further improving the performance of the entire bonding system. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the claims and description of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0023] The present invention provides a silicone-based rubber bonding method, which is used to bond the silicone-based rubber to a substrate, wherein the substrate may be made of EVA material, TPU material, rubber material, etc.

[0024] In the silicone-based rubber bonding method, the following steps are mainly included:

[0025] Step 1: Use isopropyl alcohol to brush the adhesive surface of the silicone rubber and dry it for a preset time;

[0026] Step 2: Apply adhesive to the adhesive surface of the silicone rubber and dry until the adhesive is semi-solid; the adhesive includes ethyl cyanoacrylate and epoxy resin;

[0027] Step 3: Lay the adhesive surface of the silicone-based rubber on the bonded surface of the substrate, apply and maintain pressure on the two, and complete the bonding of the silicone-based rubber.

[0028] Among them, in step one, after brushing the adhesive surface of the silicone-based rubber with isopropyl alcohol, the preset drying period in an environment of 5-35°C is 90s-150s, and the drying time decreases as the ambient temperature increases.

[0029] In step 2, after applying adhesive to the adhesive surface of the silicone rubber, the adhesive is dried at 5-35° C. for 20-30 seconds until the adhesive is semi-solid. In addition, the mass proportion of ethyl cyanoacrylate in the adhesive is 85%-87%, and the mass proportion of epoxy resin is 9%-11%.

[0030] In step 3, after the adhesive surface of the silicone rubber is attached to the adhesive surface of the substrate, the adhesive surface is pressed at 30-35 kg / cm 2 Apply pressure to both and maintain it for 20-25 seconds.

[0031] In addition, before step three, that is, before the bonded surface of the substrate is attached to the bonding surface of the silicone camera, a polyurethane adhesive is applied to the bonded surface of the substrate and dried at 50-55°C for 120-150s; the polyurethane adhesive includes 5%-8% butanone, 10%-15% dimethyl carbonate, 25%-30% acetone, 20%-25% ethyl acetate, 15%-20% methyl acetate, and 14%-16% polyurethane resin in a mass ratio.

[0032] As a preferred embodiment, the material of the substrate is preferably ethylene vinyl acetate copolymer. Before applying the polyurethane adhesive, the bonding surface of the substrate made of ethylene vinyl acetate copolymer is sequentially subjected to a reagent cleaning step and an ultraviolet irradiation treatment step; the reagent cleaning step includes sequentially cleaning the bonding surface with an alkaline liquid, a neutral liquid, and an acidic liquid; the ultraviolet irradiation treatment step includes drying the bonding surface after applying the ultraviolet irradiation treatment agent, and irradiating the bonding surface with ultraviolet light.

[0033] In the reagent cleaning step, the alkaline liquid is water with a pH value of 11-12 and a temperature of 50-55° C., the neutral liquid is water with a pH value of 7-9 and a temperature of 50-55° C., and the acidic liquid is an oxalic acid aqueous solution with a pH value of 3-4 and a temperature of 50-55° C. Moreover, the cleaning time of each liquid is preferably 90-120 seconds.

[0034] In the ultraviolet irradiation treatment step, the ultraviolet irradiation treatment agent includes 25-30% by weight of butanone, 35-40% by weight of methylcyclohexane, 30-35% by weight of ethyl acetate and 3-5% by weight of polymethyl methacrylate resin; the ultraviolet irradiation energy is 0.55-0.65 J / cm 2 .

[0035] In the silicone rubber bonding method provided by the present invention, firstly, the bonding surface of the silicone rubber is brushed with isopropyl alcohol and dried for a preset time. The isopropyl alcohol can clean the bonding surface of the silicone rubber, keep the bonding surface clean, and improve the hydrophobicity of the bonding surface. The isopropyl alcohol has no swelling property on the silicone rubber, which can reduce the damage of the organic solvent to the silicone rubber, so that the silicone rubber can still maintain its physical properties after bonding. Then, an adhesive is brushed on the bonding surface of the silicone rubber and disturbed until the adhesive is semi-solid. The adhesive adopts a product including ethyl cyanoacrylate and epoxy resin, which can be cured by reacting with water. Since the hydrophobicity of the bonding surface of the silicone rubber has been improved by isopropyl alcohol, The bonding surface of the silicone-based rubber can retain more moisture, thereby improving the curing effect of the adhesive; and the ethyl cyanoacrylate mainly included in the adhesive contains highly active functional groups such as cyano and ester groups, which can interact with the microstructure of the silicone-based rubber to achieve bonding, thereby reducing the influence of the low polarity of the silicone-based rubber on the bonding strength; and the adhesive has a fast curing speed. When it is in a semi-solid state and adhered to the bonded surface of the substrate, the curing time of the adhesive between the bonding surface and the bonded surface can be reduced, thereby reducing the impact on the silicone-based rubber during the bonding process, thereby improving the overall bonding effect, and can also retain the softness and resilience of the silicone-based rubber.

[0036] In addition, polyurethane adhesive is also applied on the bonded surface of the substrate, which can form a strong intermolecular force with the substrate, and infiltrate and adhere to the substrate, thereby providing a more solid foundation for bonding with the silicone-based rubber, further improving the bonding strength of the silicone-based rubber. In addition, polyurethane adhesive has a certain degree of flexibility and elasticity after curing, and can be combined with the adhesive of silicone-based rubber to improve the softness and resilience of silicone-based rubber after bonding, and avoid cracks in silicone-based rubber when it is bent after bonding.

[0037] Among them, when the substrate is made of ethylene vinyl acetate copolymer, the polyurethane adhesive can interweave and entangle with the molecular chains on the bonded surface of the substrate to form an interpenetrating network structure, which can make the bond between the polyurethane adhesive and the substrate tighter. At the same time, when the silicone-based rubber coated with adhesive is attached to the bonded surface of the substrate, this network structure can further interact with the adhesive to form a chemical bond, thereby further enhancing the bonding strength between the silicone-based rubber and the substrate.

[0038] When the substrate is made of ethylene vinyl acetate copolymer, a reagent cleaning step and an ultraviolet irradiation treatment step are performed in sequence before applying the polyurethane adhesive. The reagent cleaning step uses alkaline liquid, neutral liquid, and acidic liquid for cleaning in sequence, which can effectively remove impurities, oil stains and other pollutants on the surface of the substrate, improve the activity and cleanliness of the substrate surface, provide good surface conditions for subsequent ultraviolet irradiation treatment and application of polyurethane adhesive, enhance the bonding force between the polyurethane adhesive and the substrate, and indirectly improve the bonding strength between the silicone-based rubber and the substrate; the ultraviolet irradiation treatment step (drying and irradiating after applying the ultraviolet irradiation treatment agent) can further activate the substrate surface, change the molecular structure of the substrate surface, increase the surface energy, and improve the chemical reaction activity between the substrate and the polyurethane adhesive, which is conducive to forming a more solid bonding interface and further improving the performance of the entire bonding system.

[0039] To further illustrate the technical effects of the silicone-based rubber bonding method provided by the present invention, the present specification provides the following examples and comparative examples.

[0040] Example 1

[0041] Use the following steps to bond silicone rubber to EVAA substrates:

[0042] S10: Apply 99% isopropyl alcohol to the adhesive surface of the silicone rubber and dry it at 25°C for 100 seconds;

[0043] S20: Apply adhesive to the adhesive surface of the silicone rubber and dry at 25°C for 25 seconds until the adhesive is semi-solid;

[0044] S31: performing a reagent cleaning step on the bonded surface of the substrate;

[0045] S32: performing an ultraviolet irradiation step on the bonding surface of the substrate;

[0046] S33: applying polyurethane adhesive on the bonded surface of the substrate and drying at 50°C for 120s;

[0047] S40: Lay the adhesive surface of the silicone rubber to the bonded surface of the substrate at 32kg / cm 2 The pressure is applied to both and maintained for 25 seconds.

[0048] Among them, in step S20, the mass proportion of ethyl cyanoacrylate in the adhesive is 86%, and the mass proportion of epoxy resin is 10%. In step S31, the alkaline liquid is water with a pH range of 11-12 and a temperature of 50°C, the neutral liquid is water with a pH range of 7-9 and a temperature of 50°C, and the acidic liquid is an oxalic acid aqueous solution with a pH range of 3-4 and a temperature of 50°C. The cleaning time of the liquid is 90s. In step S32, the ultraviolet irradiation treatment agent includes 25% butanone, 35% methylcyclohexane, 35% ethyl acetate and 5% polymethyl methacrylate resin by mass; the ultraviolet irradiation energy is 0.6J / cm 2 In step S33, the polyurethane adhesive includes 6% by weight of butanone, 12% by weight of dimethyl carbonate, 28% by weight of acetone, 22% by weight of ethyl acetate, 18% by weight of methyl acetate, and 14% by weight of polyurethane resin.

[0049] Comparative Example 1

[0050] Comparative Example 1 is based on Example 1, except that the substrate is not processed by steps S31-S33.

[0051] Comparative Example 2

[0052] Comparative Example 2 is based on Example 1, except that in step S20, the adhesive used is a polyurethane adhesive.

[0053] Comparative Example 3

[0054] Comparative Example 3 is based on Example 1, except that dimethyl sulfoxide is used for cleaning in step S10.

[0055] The adhesive strength and other physical properties of Example 1 and Comparative Examples 1-3 were tested, and the results were as follows:

[0056]

[0057] It can be seen from the above test results that the silicone-based rubber after bonding in Example 1 has a higher bonding strength, and is not easy to debond or crack after bending, indicating that the silicone-based rubber after bonding can still maintain good physical properties; although the bonding strength of the silicone-based rubber in Comparative Example 1 can meet the requirements, it is easy to debond and crack after bending, indicating that this bonding method has caused damage to the structure of the silicone-based rubber; in Comparative Example 2, there is basically no bonding ability, indicating that the silicone-based rubber cannot be bonded using this adhesive; in Comparative Example 3, the bonding strength decreases, indicating that the use of isopropyl alcohol to brush the bonding surface of the silicone-based rubber has a certain effect on improving the bonding strength of the silicone-based rubber.

[0058] The description of the above specification and embodiments is used to explain the protection scope of the present invention, but does not constitute a limitation on the protection scope of the present invention. Through the enlightenment of the present invention or the above embodiments, ordinary technicians in this field can obtain modifications, equivalent substitutions or other improvements to the embodiments of the present invention or part of the technical features thereof through logical analysis, reasoning or limited experiments, which should be included in the protection scope of the present invention.

Claims

1. A method for bonding a silicone-based rubber to a substrate, characterized in that: include: Use isopropyl alcohol to brush the adhesive surface of the silicone rubber and let it dry for a preset time; Apply adhesive to the bonding surface of the silicone rubber and dry until the adhesive becomes semi-solid; The adhesive comprises ethyl cyanoacrylate and epoxy resin; The bonding surface of the silicone-based rubber is placed on the bonded surface of the substrate, and pressure is applied and maintained to the two to complete the bonding of the silicone-based rubber.

2. A silicone-based rubber bonding method as claimed in claim 1, characterized in that: After brushing the adhesive surface of the silicone rubber with isopropyl alcohol, the preset drying period is 90s-150s in an environment of 5-35°C, and the drying time decreases as the ambient temperature increases.

3. A silicone-based rubber bonding method as claimed in claim 1, characterized in that: After applying adhesive to the adhesive surface of the silicone rubber, dry it at 5-35℃ for 20-30s until the adhesive becomes semi-solid.

4. A silicone-based rubber bonding method as claimed in claim 3, characterized in that: In the adhesive, the mass proportion of ethyl cyanoacrylate is 85%-87%, and the mass proportion of epoxy resin is 9%-11%.

5. A silicone-based rubber bonding method as claimed in claim 1, characterized in that: After the adhesive surface of the silicone rubber is attached to the adhesive surface of the substrate, the pressure is 30-35 kg / cm 2 Apply pressure to both and maintain it for 20-25 seconds.

6. A silicone-based rubber bonding method as claimed in claim 1, characterized in that: Before being attached to the adhesive surface of the silicone camera, the bonded surface of the substrate is coated with polyurethane adhesive and dried at 50-55° C. for 120-150 seconds.

7. A silicone-based rubber bonding method as claimed in claim 6, characterized in that: The polyurethane adhesive comprises 5%-8% of butanone, 10%-15% of dimethyl carbonate, 25%-30% of acetone, 20%-25% of ethyl acetate, 15%-20% of methyl acetate, and 14%-16% of polyurethane resin in a mass proportion.

8. A silicone-based rubber bonding method as claimed in claim 6, characterized in that: The substrate is made of ethylene vinyl acetate copolymer. Before applying the polyurethane adhesive, a reagent cleaning step and an ultraviolet irradiation treatment step are performed in sequence; the reagent cleaning step includes sequentially cleaning the bonded surface with an alkaline liquid, a neutral liquid, and an acidic liquid; the ultraviolet irradiation treatment step includes drying the bonded surface after applying the ultraviolet irradiation treatment agent, and irradiating the bonded surface with ultraviolet rays.

9. A silicone-based rubber bonding method as claimed in claim 8, characterized in that: In the reagent cleaning step, the alkaline liquid is water with a pH range of 11-12 and a temperature of 50-55°C, the neutral liquid is water with a pH range of 7-9 and a temperature of 50-55°C, and the acidic liquid is an oxalic acid aqueous solution with a pH range of 3-4 and a temperature of 50-55°C.

10. A silicone-based rubber bonding method as claimed in claim 9, characterized in that: In the ultraviolet irradiation treatment step, the ultraviolet irradiation treatment agent includes 25-30% by weight of butanone, 35-40% by weight of methylcyclohexane, 30-35% by weight of ethyl acetate and 3-5% by weight of polymethyl methacrylate resin; the ultraviolet irradiation energy is 0.55-0.65 J / cm 2 .

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