A foamed silicone pressure sensitive adhesive and a method of making the same

Abstract

The application belongs to the technical field of organic materials, and particularly relates to a foamed organic silicon pressure-sensitive adhesive and a preparation method thereof. The addition reaction of silicon hydrogen bonds between a vinyl group and hydrogen-containing silicone oil forms a dense crosslinked network structure, and a hydroxyl nano reinforcing agent is added to react with the silicon hydrogen bonds to generate hydrogen, so that micro-bubbles are formed in the network structure, the cavity in the network structure is increased, and the strength of the network structure is enhanced. The application has the beneficial effect that the purpose of the application is to further reduce the film thickness of the pressure-sensitive adhesive for the display module, and the buffer performance requirement of the prior art can still be met; the foamed organic silicon pressure-sensitive adhesive provides good buffer performance by virtue of the microporous structure and the crosslinked network structure. When the OLED screen is impacted, the microporous structure and the cavity of the crosslinked network structure are deformed, so that the impact force is dispersed, and the OLED screen is prevented from being severely deformed and damaged.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic materials, and particularly relates to a foamed organic silicon pressure-sensitive adhesive and a preparation method thereof. BACKGROUND

[0002] In recent years, screen display technology has developed rapidly, and the upgrading of display technology has also promoted the technological innovation of screen-related auxiliary materials. Among them, OLED screens are developing towards lightweight and bendable, and the performance requirements for pressure-sensitive adhesive films used in display modules are more stringent. The current domestic mainstream pressure-sensitive adhesive film is acrylic foam double-sided tape, which has the disadvantages of complex assembly process, poor impact energy buffering effect, and the need to increase the thickness of the adhesive film to meet the use requirements, which is contrary to the development trend of reducing the overall thickness of OLED screens. Under the condition of the same thickness, the buffering performance of organic silicon material is stronger, which can effectively reduce the thickness of the display module.

[0003] CN117757266A discloses a silicon gel composition, a silicon gel and its application. The invention realizes the improvement of indentation and the improvement of buffering effect of the silicon gel by adding a controlled amount of high-pigment carbon black and modified multi-walled carbon nanotubes, and also endows the silicon gel with good conductive performance. Since the buffering performance of the silicon gel relies on the high-density network structure of the cross-linked silicon gel itself, it still needs to reach 130 microns or more to meet the impact resistance of the OLED screen.

[0004] In order to make the colloid have better impact resistance, some existing technologies sacrifice the strength of the colloid, resulting in insufficient adhesion to glass and steel plates. At the same time, due to the lower limit requirement of the adhesion of the pressure-sensitive adhesive used in the OLED screen display module, the existing technology cannot further increase the impact resistance by reducing the adhesion strength, ultimately resulting in the inability to reduce the thickness of the pressure-sensitive adhesive used in the OLED screen display module.

[0005] Therefore, in order to solve the defects of the prior art, the present application proposes a foamed organic silicon pressure-sensitive adhesive which has stronger adhesion to glass and steel plates and stronger impact resistance under the same thickness. SUMMARY

[0006] In order to solve the above-mentioned deficiencies in the field, a glue that meets the current packaging requirements of OLED screens has been invented, which can not only reduce the thickness, but also provide adhesion strength and impact resistance.

[0007] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0008] The application provides a foamed organic silicone pressure-sensitive adhesive, which is formed by addition reaction of silicon hydrogen bonds between vinyl groups and hydrogen-containing silicone oil to form a dense crosslinked network structure, and addition of a hydroxyl nano reinforcing agent to react with the silicon hydrogen bonds to generate hydrogen, form micro-bubbles in the network structure, increase the cavities in the network structure to provide impact resistance, and meanwhile, the nano reinforcing agent has high mechanical strength and can compensate for the reduced cohesive strength caused by the cavities due to hydrogen, and the components thereof include, by weight fraction:

[0009] vinyl raw rubber 30-70 parts

[0010] hydroxyl nano reinforcing agent 5-10 parts

[0011] hydroxyl silicone oil 15-30 parts

[0012] methyl MQ resin 15-85 parts

[0013] hydroxyl MQ resin 15-40 parts

[0014] inhibitor 0.01-0.5 parts

[0015] hydrogen-containing silicone oil 0.2-2 parts

[0016] catalyst 0.3-2 parts

[0017] organic solvent 100-200 parts

[0018] The vinyl raw rubber is methyl vinyl polysiloxane, and the molecular weight is 500-800,000, and the vinyl content is 0.01-0.09wt%.

[0019] The hydroxyl nano reinforcing agent is one or more of nano cellulose, hydroxyl nanotube and silicon hydroxyl silicon dioxide.

[0020] The hydroxyl silicone oil is end hydroxyl methyl polysiloxane, and the viscosity is 10-100 mPa·s; the hydroxyl content of the end hydroxyl methyl polysiloxane is 1-15%.

[0021] As a preferred technical solution of the application, the diameter of the nano cellulose is 3-5nm, and the fiber length is 500-1000nm.

[0022] As a preferred technical solution of the application, the M / Q value of the methyl MQ resin is 0.6-0.9, the relative molecular mass is 3500-6000g / mol, and the hydroxyl content is less than 0.5wt%.

[0023] As a preferred technical solution of the application, the M / Q value of the hydroxyl MQ resin is 0.5-0.9, the relative molecular mass is 3000-6500g / mol, and the hydroxyl content is 0.5-2.5wt%.

[0024] As a preferred technical solution of the present application, the inhibitor is one or more of ethynylcyclohexanol, maleic acid diallyl ester, 2-methyl-3-butyn-2-ol, tetramethyldivinyl disiloxane, tetramethyltetraethenylcyclotetrasiloxane, and 3-methyl-1-dodecyn-3-ol.

[0025] As a preferred technical solution of the present application, the hydrogen-containing silicone oil is one or more of hydrogen-containing silicone oils containing terminal hydrogen groups and side hydrogen groups, with a viscosity of 5-100 mPa·s and a total hydrogen content of 0.1-2.0%.

[0026] As a preferred technical solution of the present application, the catalyst is a platinum-gold catalyst with a platinum content of 0.25-0.6%.

[0027] As a preferred technical solution of the present application, the organic solvent is one or more of toluene, xylene, ethyl acetate, butyl acetate, cyclohexane, and n-hexane.

[0028] In another aspect, the present application provides a preparation method of the above-mentioned foamed silicone pressure-sensitive adhesive, which comprises the following steps:

[0029] (1) mixing 30-70 parts of vinyl raw rubber, 5-10 parts of a hydroxyl nano reinforcing agent, 15-30 parts of a hydroxyl silicone oil, 15-85 parts of a methyl MQ resin, 15-40 parts of a hydroxyl MQ resin, 0.01-0.5 parts of an inhibitor, and an appropriate amount of a solvent, and heating to react, to obtain a silicone pressure-sensitive adhesive main agent;

[0030] (2) adding an appropriate amount of a solvent to the silicone pressure-sensitive adhesive main agent obtained in step (1) and stirring thoroughly, then adding 0.2-2 parts of a hydrogen-containing silicone oil and stirring thoroughly, and adding an appropriate amount of a catalyst and stirring thoroughly, to obtain a silicone pressure-sensitive adhesive coating liquid;

[0031] (3) coating the silicone pressure-sensitive adhesive coating liquid on a first fluorine release film with a thickness of 50 μm, placing it in an oven for curing and taking it out, with a dry adhesive thickness of 100 μm, and laminating a second fluorine release film with a thickness of 50 μm on the upper surface of the dry adhesive, to obtain the foamed silicone pressure-sensitive adhesive.

[0032] As a preferred technical solution of the present application, the solvent is one or more of anhydrous ethanol, xylene, and chloroform.

[0033] As a preferred technical solution of the present application, the heating reaction temperature in step (1) is 120°C, and the curing method in step (3) is placing the first fluorine release film coated with the silicone pressure-sensitive adhesive coating liquid in an oven at 100°C for 1 min, then placing it in an oven at 150°C for 2 min, and taking it out.

[0034] By adopting the technical scheme, the present application has the beneficial effects that:

[0035] The present application forms a dense crosslinked structure by addition reaction of the vinyl group and the silicon hydrogen bond of the hydrogen-containing silicone oil, adds a hydroxyl nano reinforcing agent, makes it react with the silicon hydrogen bond to generate hydrogen, makes the micro-bubbles full of hydrogen in the crosslinked structure, thereby forms a dense crosslinked structure similar to a sponge, the structure has good impact resistance, and since the nano reinforcing agent has high mechanical strength, it can make up for the reduced cohesive strength caused by the cavities of hydrogen, and further reduce the cohesive strength, therefore, compared with the prior art, the present application can effectively reduce the thickness of the pressure-sensitive adhesive film for display modules, and still meet the buffering performance requirements of the prior art.

[0036] The foamed silicone pressure-sensitive adhesive of the present application provides good buffering performance by virtue of its microporous structure and crosslinked network structure, when the OLED screen is impacted, the microporous structure and the cavities of the crosslinked network structure will be deformed, thereby dispersing the impact force and avoiding serious deformation damage to the OLED screen. BRIEF DESCRIPTION OF DRAWINGS

[0037] The accompanying drawings, which form a part of this application, are used to provide further understanding of the application, and the schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitations on the present application.

[0038] Figure 1 Structure schematic diagram of the silicone pressure-sensitive adhesive prepared for example 1, example 2, example 3 and example 4 of the present application.

[0039] In the figure: 1, silicone pressure-sensitive adhesive coating solution; 2, first fluorine release film; 3, second fluorine release film. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed description is all exemplary, and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs.

[0041] It should be noted that the terms used herein are only for the purpose of 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 intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component and / or their combinations.

[0042] The present application will be further illustrated below in conjunction with the accompanying drawings and examples.

[0043] Example 1

[0044] Raw materials include:

[0045] First vinyl gum 35 g

[0046] Second vinyl gum 5 g

[0047] Hydroxyl silicone oil 15 g

[0048] Xylene 150 g

[0049] Hydroxyl nano-reinforcing agent 5 g

[0050] Methyl MQ resin 40 g

[0051] Hydroxyl MQ resin 12 g

[0052] Inhibitor 0.01 g

[0053] Hydrogen-containing silicone oil 0.3 g

[0054] Catalyst 0.8 g

[0055] wherein,

[0056] The first vinyl gum is a methyl vinyl polysiloxane: weight average molecular weight 650,000, vinyl content 0.06 wt%;

[0057] The second vinyl gum is a methyl vinyl polysiloxane: weight average molecular weight 800,000, vinyl content 0.09 wt%;

[0058] The nano-reinforcing agent is a nanocellulose: fiber diameter 3-5 nm, fiber length 500-1000 nm.

[0059] The methyl MQ resin: M / Q is 0.75, molar mass 5000 g / mol, hydroxyl content 0.3 wt%.

[0060] The hydroxyl MQ resin: M / Q is 0.75, molar mass 3000 g / mol, hydroxyl content 3.0 wt%.

[0061] The inhibitor is ethynylcyclohexanol.

[0062] The hydrogen-containing silicone oil is a hydrogen-containing silicone oil with a side hydrogen group: viscosity 9 mpa.s, hydrogen content 1.6%.

[0063] The catalyst is a platinum gold catalyst: platinum content 5000 ppm.

[0064] Into a three-necked flask were added 35 g of a first vinyl gum, 5 g of a second vinyl gum, 15 g of a hydroxyl silicone oil, 5 g of a nanocellulose, 40 g of a methyl MQ resin, 5 g of a hydroxyl MQ resin, 0.01 g of an inhibitor, and 80 g of xylene, and the mixture was stirred at 120°C for 4 hours, and refluxed twice to obtain a silicone pressure-sensitive adhesive main agent. To the silicone pressure-sensitive adhesive main agent were added 70 g of xylene, and the mixture was stirred with an electric mixer for 5 minutes, followed by dropwise addition of 0.3 g of a hydrogen-containing silicone oil, and the mixture was stirred with an electric mixer for 5 minutes, followed by dropwise addition of 0.8 g of a catalyst, and the mixture was stirred with an electric mixer for 5 minutes to obtain a silicone pressure-sensitive adhesive coating solution. The silicone pressure-sensitive adhesive coating solution was coated on a 50-μm-thick first fluorine release film, and the coated film was placed in an oven at 100°C for 1 minute, and then placed in an oven at 150°C for 2 minutes, and then taken out, and the dry gum thickness was 100 μm, and a 50-μm-thick second fluorine release film was attached to the dry gum. A foamed silicone pressure-sensitive adhesive sample film was prepared.

[0065] Example 2

[0066] The raw materials included:

[0067] 35 g of a first vinyl gum

[0068] 5 g of a second vinyl gum

[0069] 20 g of a hydroxyl silicone oil

[0070] 150 g of xylene

[0071] 5 g of a hydroxyl nanoreinforcing agent

[0072] 40 g of a methyl MQ resin

[0073] 12 g of a hydroxyl MQ resin

[0074] 0.01 g of an inhibitor

[0075] 0.3 g of a first hydrogen-containing silicone oil

[0076] 0.3 g of a second hydrogen-containing silicone oil

[0077] 0.8 g of a catalyst

[0078] wherein,

[0079] the first vinyl gum is a methyl vinyl polysiloxane having a weight average molecular weight of 650,000 and a vinyl content of 0.06 wt%,

[0080] the second vinyl gum is a methyl vinyl polysiloxane having a weight average molecular weight of 800,000 and a vinyl content of 0.09 wt%,

[0081] the nanoreinforcing agent is a nanocellulose having a fiber diameter of 3-5 nm and a fiber length of 500-1000 nm.

[0082] The methyl MQ resin: M / Q is 0.75, the molar mass is 5000 g / mol, and the hydroxyl content is 0.3 wt%.

[0083] The hydroxyl MQ resin: M / Q is 0.75, the molar mass is 3000 g / mol, and the hydroxyl content is 3.0 wt%.

[0084] The inhibitor is ethynylcyclohexanol.

[0085] The first hydrogen-containing silicone oil is a side-hydrogen-containing silicone oil: viscosity 9 mpa.s, hydrogen content 1.4%.

[0086] The second hydrogen-containing silicone oil is an end-hydrogen-containing silicone oil: viscosity 15 mpa.s, hydrogen content 0.2%.

[0087] The catalyst is a platinum-gold catalyst: platinum content 5000 ppm.

[0088] The preparation method is the same as that of Example 1.

[0089] Example 3

[0090] The raw materials include:

[0091] Vinyl gum 40 g

[0092] Hydroxyl silicone oil 30 g

[0093] Xylene 150 g

[0094] Nano reinforcing agent 8 g

[0095] Methyl MQ resin 44 g

[0096] Hydroxyl MQ resin 8 g

[0097] Inhibitor 0.01 g

[0098] Hydrogen-containing silicone oil 0.3 g;

[0099] Catalyst 0.8 g.

[0100] Among them,

[0101] The vinyl gum is a methyl vinyl polysiloxane: weight average molecular weight 650,000, vinyl content 0.06 wt%.

[0102] The nano reinforcing agent is a nanocellulose: fiber diameter 3-5 nm, fiber length 500-1000 nm.

[0103] The methyl MQ resin: M / Q is 0.75, the molar mass is 5000 g / mol, and the hydroxyl content is 0.3 wt%.

[0104] The hydroxyl MQ resin: M / Q is 0.75, the molar mass is 3000 g / mol, and the hydroxyl content is 3.0 wt%.

[0105] The inhibitor is ethynylcyclohexanol.

[0106] The hydrogen-containing silicone oil is a side hydrogen-containing silicone oil: viscosity 9 mpa.s, hydrogen content 1.6%.

[0107] The catalyst is a platinum gold catalyst: platinum content 5000 ppm.

[0108] The preparation method is the same as that of Example 1. Example

[0109] The raw materials include:

[0110] Vinyl gum 40 g

[0111] Hydroxyl silicone oil 25 g

[0112] Xylene 150 g

[0113] Nano reinforcing agent 8 g

[0114] Methyl MQ resin 44 g

[0115] Hydroxyl MQ resin 8 g

[0116] Inhibitor 0.01 g

[0117] Hydrogen-containing silicone oil 0.3 g;

[0118] Catalyst 0.8 g.

[0119] Among them,

[0120] The vinyl gum is a methyl vinyl polysiloxane: weight average molecular weight 650,000, vinyl content 0.06 wt%;

[0121] The nano reinforcing agent is a mixture of silicon hydroxyl silica and nanocellulose in a mass ratio of 1:1.

[0122] The methyl MQ resin: M / Q is 0.75, the molar mass is 5000 g / mol, and the hydroxyl content is 0.3 wt%.

[0123] The hydroxyl MQ resin: M / Q is 0.75, the molar mass is 3000 g / mol, and the hydroxyl content is 3.0 wt%.

[0124] The inhibitor is ethynylcyclohexanol.

[0125] The hydrogen-containing silicone oil is a side hydrogen-containing silicone oil: viscosity 9 mpa.s, hydrogen content 1.6%.

[0126] The catalyst is a platinum gold catalyst: platinum content 5000 ppm.

[0127] The preparation method is the same as that of Example 1.

[0128] To verify the technical effect of the present application, comparative tests were carried out to prepare the following comparative examples using the common glue agent in the prior art.

[0129] Comparative Example 1

[0130] The raw materials include:

[0131] Vinyl raw rubber 51 g

[0132] Methyl MQ resin 74 g

[0133] Xylene 150 g

[0134] Inhibitor 0.01 g

[0135] First hydrogen-containing silicone oil 0.15 g

[0136] Second hydrogen-containing silicone oil 0.15 g

[0137] Catalyst 0.8 g

[0138] Among them,

[0139] The vinyl raw rubber is methyl vinyl polysiloxane: weight average molecular weight 650,000, vinyl content 0.06 wt.%;

[0140] The methyl MQ resin: M / Q is 0.75, molar mass is 5000 g / mol, and the hydroxyl content is 0.3 wt.%.

[0141] The inhibitor is ethynylcyclohexanol.

[0142] The first hydrogen-containing silicone oil is a hydrogen-containing silicone oil with side hydrogen groups: viscosity 9 mpa.s, hydrogen content 1.4%.

[0143] The second hydrogen-containing silicone oil is a hydrogen-containing silicone oil with end hydrogen groups: viscosity 15 mpa.s, hydrogen content 0.2%.

[0144] The catalyst is a platinum gold catalyst: platinum content 5000 ppm.

[0145] Preparation method

[0146] Take 51 g of vinyl gum, 74 g of methyl MQ resin, 0.01 g of inhibitor, mix, add 150 g of xylene, stir with an electric mixer for 5 minutes, then add 0.15 g of the first hydrogen-containing silicone oil, stir with an electric mixer for 5 minutes, then add 0.15 g of the second hydrogen-containing silicone oil, stir with an electric mixer for 5 minutes, and finally add 0.8 g of catalyst, stir with an electric mixer for 5 minutes, to obtain a silicone pressure-sensitive adhesive coating solution. The silicone pressure-sensitive adhesive coating solution is coated on a 50 μm thick first fluorine release film, which is placed in an oven at 100°C for 1 min, then placed in an oven at 150°C for 2 min, taken out, the dry adhesive thickness is 100 μm, and a 50 μm thick second fluorine release film is attached. A foamed silicone pressure-sensitive adhesive sample film is prepared.

[0147] Comparative Example 2

[0148] The raw materials include:

[0149] First vinyl gum 35 g

[0150] Second vinyl gum 25 g

[0151] Xylene 150 g

[0152] Methyl MQ resin 40 g

[0153] Hydroxyl MQ resin 12 g

[0154] Inhibitor 0.01 g

[0155] Hydrogen-containing silicone oil 0.3 g

[0156] Catalyst 0.8 g

[0157] Among them,

[0158] The first vinyl gum is a methyl vinyl polysiloxane: weight average molecular weight 650,000, vinyl content 0.06 wt%;

[0159] The second vinyl gum is a methyl vinyl polysiloxane: weight average molecular weight 800,000, vinyl content 0.09 wt%;

[0160] The methyl MQ resin: M / Q is 0.75, the molar mass is 5000 g / mol, and the hydroxyl content is 0.3 wt%.

[0161] The hydroxyl MQ resin: M / Q is 0.75, the molar mass is 3000 g / mol, and the hydroxyl content is 3.0 wt%.

[0162] The inhibitor is ethynylcyclohexanol.

[0163] The hydrogen-containing silicone oil is a side hydrogen-containing silicone oil: viscosity 9 mpa.s, hydrogen content 1.4%.

[0164] The catalyst is a platinum gold catalyst: platinum content 5000 ppm.

[0165] Preparation method:

[0166] Take 35 g of the first vinyl raw rubber, 25 g of the second vinyl raw rubber, 40 g of the methyl MQ resin, 12 g of the hydroxyl MQ resin, 0.01 g of the inhibitor, mix them, add 150 g of xylene, stir with an electric mixer for 5 minutes, then add 0.3 g of hydrogen-containing silicone oil dropwise, stir with an electric mixer for 5 minutes, finally add 0.8 g of catalyst dropwise, stir with an electric mixer for 5 minutes, and obtain a silicone pressure-sensitive adhesive coating solution. The silicone pressure-sensitive adhesive coating solution is coated on a 50 μm thick first fluorine release film, which is placed in an oven at 100°C for 1 min for curing, then placed in an oven at 150°C for 2 min for curing, taken out, the dry adhesive thickness is 100 μm, and a 50 μm thick second fluorine release film is attached. A foamed silicone pressure-sensitive adhesive sample film is prepared and tested.

[0167] Comparative Example 3

[0168] Raw materials include:

[0169] Vinyl raw rubber 35 g

[0170] Xylene 81 g

[0171] Hydroxyl silicone oil 30 g

[0172] Methyl MQ resin 35 g

[0173] Inhibitor 0.01 g

[0174] Hydrogen-containing silicone oil 0.09 g

[0175] Catalyst 0.24 g

[0176] Preparation method:

[0177] Into a three-necked flask were added 35 g of vinyl raw rubber, 30 g of hydroxyl silicone oil, 35 g of methyl MQ resin, 0.01 g of inhibitor, 66 g of xylene, and the mixture was stirred at 120°C for 4 hours, and refluxed twice to obtain a silicone pressure-sensitive adhesive main agent. 30 g of the silicone pressure-sensitive adhesive main agent was taken, 15 g of xylene was added, and the mixture was stirred with an electric mixer for 5 minutes. Then, 0.09 g of hydrogen-containing silicone oil was added dropwise, and the mixture was stirred with an electric mixer for 5 minutes. Finally, 0.24 g of catalyst was added dropwise, and the mixture was stirred with an electric mixer for 5 minutes to obtain a silicone pressure-sensitive adhesive coating liquid. The silicone pressure-sensitive adhesive coating liquid was coated on a first fluorine release film with a thickness of 50 μm, and the coated film was placed in an oven at 100°C for 1 minute and then in an oven at 150°C for 2 minutes to obtain a dried film with a thickness of 100 μm. A second fluorine release film with a thickness of 50 μm was attached to the dried film. A foamed silicone pressure-sensitive adhesive sample film was prepared.

[0178] The samples prepared in each of the above examples and comparative examples were tested by the following test methods.

[0179] (1) 180° peeling force test: The test was performed according to GB / T 2792-2014 "Test method for peel strength of adhesive tape". The sample was cut to a width of 25 mm, the second fluorine release film was peeled off, and the 25 μm PET original film was peeled off. The other side was attached to a SUS standard test plate, and the 180° peeling force of the adhesive tape was tested.

[0180] (2) 85°C high-temperature 180° peeling force test: The test was performed according to GB / T 2792-2014 "Test method for peel strength of adhesive tape". The sample was cut to a width of 25 mm, the second fluorine release film was peeled off, and the 25 μm PET original film was peeled off. The other side was attached to a SUS standard test plate, and the 180° peeling force was tested immediately after the sample was placed in an oven at 85°C for 5 minutes.

[0181] (3) Anti-point impact rate: The first fluorine release film and the second fluorine release film were peeled off the sample, and the sample was fixed on a device base. The device base had a force sensor. A steel ball of a certain size was placed at a height of 150 mm, and the steel ball was dropped vertically using an electromagnetic valve. The force value F1 of the steel ball falling on the sample film was recorded. The sample film was removed, and the test was repeated. The force value F0 of the steel ball falling directly on the base was recorded. The point impact rate was (F0-F1) / F0, and the anti-point impact rate was required to be > 65%.

[0182] Test results: (100 μm adhesive thickness)

[0183] ;

[0184] It can be seen that the peel strength of Example 1 and Example 3 belong to the first echelon, but the point impact resistance of Example 3 is not as good as that of Example 1, and the overall technical performance of Example 1 is the best. Example 2 uses a compound hydrogen-containing silicone oil, adds a hydrogen-terminated hydrogen-containing silicone oil, and increases the length of the silicon-hydrogen crosslinking segment, so that the gel modulus is lower, the point impact resistance is higher, but the strength is reduced, resulting in a decrease in the bonding strength. Example 3 increases the amount of low molecular weight vinyl gum, methyl MQ resin and hydroxyl nano reinforcing agent. The gel cohesive strength of Example 3 is higher than that of Example 1, but the micro-bubble is reduced, and the point impact resistance is reduced. Example 4 uses a compound nano reinforcing agent scheme compared to Example 3, and Example 4 is more resistant to high temperature, but the bonding strength and point impact resistance are reduced.

[0185] Comparative Example 1 does not add a hydroxyl nano reinforcing agent, but only adds a hydrogen-terminated hydrogen-containing silicone oil to make the gel modulus lower, but because the bonding strength is greatly reduced, the point impact resistance is also the lowest among all the experimental examples. Comparative Example 2 uses a compound of vinyl gum and MQ resin to improve the cohesive strength, and the bonding strength and point impact resistance are improved compared to Comparative Example 1, but there is still a big gap compared to the examples. Comparative Example 3 uses a hydroxyl silicone oil to foam, and does not add a hydroxyl nano reinforcing agent, so it can be seen that Comparative Example 3 has better point impact resistance than the examples, but the bonding strength is lower.

[0186] Finally, it can be seen that the foamed silicone pressure-sensitive adhesive of the present application has the performance of bonding strength and point impact resistance.

[0187] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A foamed silicone pressure-sensitive adhesive, characterized in that: Through the addition reaction of vinyl groups and the silicon-hydrogen bonds of hydrogen-containing silicone oil, a dense cross-linked network structure is formed. Hydroxyl nano-reinforcement agents are added to react with the silicon-hydrogen bonds to generate hydrogen, forming microbubbles in the network structure and increasing the cavities in the network structure to provide impact resistance. At the same time, the nano-reinforcement agent has high mechanical strength and can compensate for the reduced cohesive strength caused by the cavities caused by hydrogen. Its components, by weight, include: 30-70 parts of vinyl rubber 5-10 parts of hydroxy nano-reinforcement agent 15-30 parts of hydroxy silicone oil 15-85 parts of methyl MQ resin 15-40 parts of hydroxy MQ resin 0.01-0.5 parts of inhibitor 0.2-2 parts of hydrogen silicone oil 0.3-2 parts of catalyst 100-200 parts of organic solvent Wherein, the vinyl raw rubber is methyl vinyl polysiloxane, and its molecular weight is 500,000 to 800,000, and the vinyl content is 0.01 to 0.09 wt%; The hydroxy nano reinforcing agent is one or more of nanocellulose, hydroxy carbon nanotubes, and silanol silica; The hydroxy silicone oil is terminal hydroxymethyl polysiloxane with a viscosity of 10 to 100 mPa·s; the hydroxyl content of the terminal hydroxymethyl polysiloxane is 1 to 15%.

2. The pressure-sensitive adhesive according to claim 1, characterized in that The diameter of the nanocellulose is 3-5 nm, and the fiber length is 500-1000 nm.

3. The pressure-sensitive adhesive according to claim 1, characterized in that The methyl MQ resin has an M / Q value of 0.6 to 0.9, a relative molecular mass of 3500 to 6000 g / mol, and a hydroxyl content of less than 0.5 wt %.

4. The pressure-sensitive adhesive according to claim 1, characterized in that The hydroxy MQ resin has an M / Q value of 0.5 to 0.9, a relative molecular mass of 3000 to 6500 g / mol, and a hydroxyl content of 0.5 to 2.5 wt %.

5. The pressure-sensitive adhesive according to claim 1, characterized in that The inhibitor is one or more of ethynylcyclohexanol, diallyl maleate, 2-methyl-3-butyn-2-ol, tetramethyldivinyldisiloxane, tetramethyltetravinylcyclotetrasiloxane, and 3-methyl-1-dodecyn-3-ol.

6. The pressure-sensitive adhesive according to claim 1, characterized in that The hydrogen-containing silicone oil is one or more hydrogen-containing silicone oils containing terminal hydrogen groups and pendant hydrogen groups, has a viscosity of 5 to 100 mPa·s, and a total hydrogen content of 0.1 to 2.0%.

7. The pressure-sensitive adhesive according to claim 1, characterized in that The catalyst is a platinum catalyst with a platinum content of 0.25-0.6%.

8. The pressure-sensitive adhesive according to claim 1, characterized in that The organic solvent is one or more of toluene, xylene, ethyl acetate, butyl acetate, cyclohexane, and n-hexane.

9. A method for preparing a foamed silicone pressure-sensitive adhesive according to any one of claims 1 to 7, characterized in that: The preparation method is: (1) In parts by weight, 30 to 70 parts of vinyl rubber, 5 to 10 parts of hydroxy nano-reinforcement agent, 15 to 30 parts of hydroxy silicone oil, 15 to 85 parts of methyl MQ resin, 15 to 40 parts of hydroxy MQ resin, 0.01 to 0.5 parts of inhibitor, and 100 to 200 parts of organic solvent are mixed and heated to react to obtain a silicone pressure-sensitive adhesive main agent; (2) adding an appropriate amount of organic solvent to the organic silicone pressure-sensitive adhesive main agent obtained in step (1) and stirring thoroughly, then adding 0.2-2 parts of hydrogenated silicone oil and stirring thoroughly, and adding 0.3-2 parts of catalyst and stirring thoroughly to obtain an organic silicone pressure-sensitive adhesive coating liquid; (3) The silicone pressure-sensitive adhesive coating liquid is coated on a first fluorocarbon release film with a thickness of 50 μm, which is placed in an oven for curing and taken out. The thickness of the dry adhesive is 100 μm. A second fluorocarbon release film with a thickness of 50 μm is attached to the upper surface of the dry adhesive to obtain the foamed silicone pressure-sensitive adhesive.

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