Solvent-free organic silicon pressure-sensitive adhesive and preparation method thereof

Abstract

The invention relates to the field of machines, in particular to a solvent-free organic silicon pressure-sensitive adhesive and preparation thereof.The solvent-free organic silicon pressure-sensitive adhesive is composed of 100 parts of methyl MQ silicon resin, 30-150 parts of linear polysiloxane, 10-180 parts of branched chain polysiloxane, 1-5 parts of an additive, 1-10 parts of a cross-linking agent and 0.1-1 part of an inhibitor. The pressure-sensitive adhesive does not contain an organic solvent, is environment-friendly, and can well infiltrate a pasted object.

Description

Technical Field

[0001] The present invention relates to the field of organic silicon, and more specifically, to a solvent-free organic silicon pressure-sensitive adhesive and its preparation. Background Art

[0002] Silicone pressure-sensitive adhesive is generally composed of elastic and flexible silicone rubber and silicone resin. Compared with rubber and acrylate pressure-sensitive adhesives, silicone pressure-sensitive adhesive has higher moisture resistance, chemical resistance, high and low temperature resistance, as well as excellent biocompatibility and dielectric properties. Its operating temperature range is -75 to 260°C, and the short-term operating temperature can even reach 300°C. It has broad market application prospects in the fields of electronics, medical care, aerospace, etc. In addition, it can also bond a variety of difficult-to-bond materials, such as polyolefins, fluoroplastics, polyimides, and polycarbonates that have not been surface-treated. Especially when there are certain requirements for high temperature resistance and service life, silicone pressure-sensitive adhesive has irreplaceable advantages and has broad market application prospects. With the development requirements of new processes and new technologies, the viscosity range of protective films is required to expand in the direction of a very narrow viscosity range and low climbing. Silicone protective films are widely used in the process shipment protection of electronic products, but general protective films are not resistant to high temperatures. Even if they are resistant to high temperatures, they will produce peeling force climbing, silicon migration or residual glue after high temperatures, which seriously affects customers' product experience.

[0003] Organic silicon pressure-sensitive adhesives require suitable viscosity during preparation, and generally need to be diluted with a large amount of organic solvents such as benzene and toluene, but these solvents can cause a lot of environmental pollution. Therefore, in order to meet environmental protection requirements and market demand for low-climbing and low-migration pressure-sensitive adhesives, the present invention provides a solvent-free organic silicon pressure-sensitive adhesive that is easy to apply and has low migration and low-climbing properties, and a preparation method thereof. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a solvent-free silicone pressure-sensitive adhesive, which is composed, by weight, of 100 parts of methyl MQ silicone resin, 30 to 150 parts of linear polysiloxane, 10 to 180 parts of branched polysiloxane, 1 to 5 parts of additives, 1 to 10 parts of cross-linking agents and 0.1 to 1 part of inhibitors.

[0005] Furthermore, the linear polysiloxane is a polysiloxane whose terminal group is an alkenyl group and the side group is a methyl group;

[0006] Furthermore, the branched polysiloxane is a polysiloxane whose terminal group is an alkenyl group and whose side groups are methyl and alkenyl groups.

[0007] Furthermore, the viscosity of the linear polysiloxane is 100 mPa·s to 100000 mPa·s at 25°C.

[0008] Furthermore, the molecular formula of the linear polysiloxane is (R 1 2R 2 SiO)-((CH3)2SiO) a -(OSiR 1 2R 2 ), where each R 1 Each R is independently selected from vinyl, phenyl, hydroxyl, hydrogen, alkoxy or hydrocarbon groups having 1 to 10 carbon atoms. 2 The present invention is selected from alkenyl groups having 1 to 10 carbon atoms, and a is an integer from 1 to 2500; preferably, a is an integer from 500 to 2500.

[0009] Furthermore, the viscosity of the branched polysiloxane is 100 mPa·s to 100000 mPa·s at 25°C.

[0010] Furthermore, the molecular formula of the branched polysiloxane is (R 1 2R 2 SiO)-((CH3)2SiO) a -(CH3R 2 SiO) b -(OSiR 1 2R 2 ), wherein each R1 is independently selected from vinyl, phenyl, hydroxyl, hydrogen, alkoxy or hydrocarbon groups having 1 to 10 carbon atoms, and each R 2 The present invention is selected from alkenyl groups having 1 to 10 carbon atoms, and a and b are integers in the range of 1 to 2500.

[0011] Preferably, the R 1 is selected from methyl or vinyl, R 2 Selected from vinyl, wherein the vinyl content is 0.05% to 0.31%.

[0012] Furthermore, the additive is at least one of nano silicon dioxide, nano titanium dioxide or nano aluminum oxide.

[0013] Furthermore, the BET specific surface area of ​​the additive is 50 to 500 m 2 / g.

[0014] Furthermore, the MQ resin molecular formula is (R 1 3SiO 1 / 2 ) m (SiO 4 / 2 ) n , where the ratio of m:n is 0.6 to 1.2.

[0015] Furthermore, the ratio of m:n is 0.6 to 0.9.

[0016] Preferably, the weight average molecular weight of the MQ resin is 1,000 to 20,000.

[0017] More preferably, the weight average molecular weight of the MQ resin is 3000-9000.

[0018] Further, the MQ resin has a silanol content of 0.01% to 5%.

[0019] More preferably, the MQ resin has a silanol content of 0.05% to 3.5%.

[0020] Furthermore, the crosslinking agent is at least one of linear, branched or cyclic hydrogen-containing polysiloxane.

[0021] Furthermore, each molecule of the cross-linking agent contains at least two or three Si-H groups, and the content of Si-H is 0.01-1.60%.

[0022] Furthermore, the viscosity of the cross-linking agent at 25° C. is 10 mPa·s to 1000 mPa·s; preferably, the viscosity is 20 mPa·s to 300 mPa·s.

[0023] Furthermore, the inhibitor is at least one of 3-methyl-2-butynol, 1-ethynyl-cyclohexanol, diallyl maleate, and 3,5-dimethyl-1-hexyn-3-ol.

[0024] The present invention also provides a method for preparing a solvent-free silicone pressure-sensitive adhesive, comprising:

[0025] Add 100 parts of methyl MQ silicone resin, 30-150 parts of linear polysiloxane, 10-180 parts of branched polysiloxane and 1-5 parts of additives and mix evenly, increase the temperature, and reduce the pressure to remove low molecular weight;

[0026] 1 to 10 parts of a cross-linking agent are added, and after cooling, 0.1 to 1 part of an inhibitor is added, and mixed evenly to obtain the pressure-sensitive adhesive.

[0027] Furthermore, the temperature rising condition is 90°C to 180°C, the time for removing low molecular weight is 1h to 5h, and the decompression pressure is -0.09 to -0.1MPa.

[0028] Beneficial effects of this patent:

[0029] 1. This patent uses polysiloxane structures of different structures, and constructs a special network structure of silicone pressure-sensitive adhesive through the structural combination of linear polymers and branched polymers, so that the product has the characteristics of low climbing. Traditional silicone pressure-sensitive adhesives mostly use linear polysiloxane structures, which makes the cross-linking degree of the pressure-sensitive adhesive after curing too small, the peeling force stability of the pressure-sensitive adhesive is poor, and the aging climbing is serious. Using branched polysiloxane polymers alone makes the cross-linking degree of the pressure-sensitive adhesive too large after curing, the hardness of the pressure-sensitive adhesive is too large, the initial viscosity decreases, and it cannot be well infiltrated into the adhered object.

[0030] 2. By increasing the temperature and reducing the pressure to remove the low-molecular steps during the preparation process, most of the volatile small molecules in the system can be removed. At the same time, the introduction of high surface energy fillers (i.e. additives) can construct a physical cross-linking network and physically adsorb the residual small molecules, effectively fix the residual small molecules in the cured pressure-sensitive adhesive, and solve the ghosting caused by the transfer of the pressure-sensitive adhesive to the adhered object under high temperature and high humidity environment.

[0031] 3. The reaction system does not contain organic solvents, which can avoid the damage of solvents to people and the environment. The silicone resin and polysiloxane are dispersed and mixed by hot-melt dispersion technology, and there is no need to add solvents to the system to prepare green and environmentally friendly pressure-sensitive adhesives.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims, etc. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the appendix of the specific embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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.

[0034] The embodiment of the present invention provides a solvent-free silicone pressure-sensitive adhesive, which is composed of 100 parts of methyl MQ silicone resin, 30-150 parts of linear polysiloxane, 10-180 parts of branched polysiloxane, 1-5 parts of additives, 1-10 parts of cross-linking agent and 0.1-1 part of inhibitor, in parts by weight.

[0035] The present invention constructs a special network structure of an organic silicone pressure-sensitive adhesive through a structural combination of long-chain structural components and short-chain structural components, linear polymers and branched polymers. The structure has the characteristics of no need for solvents, stable peeling force and less silicon migration. The structure solves the problems of existing organic silicone pressure-sensitive adhesives being prepared into protective films, tapes and other materials, such as ghosting after high temperature and unstable peeling force after high-humidity aging.

[0036] In another embodiment of the present invention, the linear polysiloxane is a polysiloxane having an alkenyl terminal group and a methyl side group.

[0037] In another embodiment of the present invention, the branched polysiloxane is a polysiloxane whose terminal group is an alkenyl group and whose side groups are methyl and alkenyl groups.

[0038] In another embodiment of the present invention, the viscosity of the linear polysiloxane is 100 mPa·s to 100000 mPa·s at 25°C.

[0039] In another embodiment of the present invention, the molecular formula of the linear polysiloxane is (R 1 2R 2 SiO)-((CH3)2SiO) a -(OSiR 1 2R 2 ), wherein each R1 is independently selected from vinyl, phenyl, hydroxyl, hydrogen, alkoxy or hydrocarbon groups having 1 to 10 carbon atoms, and each R 2 is selected from alkenyl groups having 1 to 10 carbon atoms, and a is an integer from 1 to 2500.

[0040] In another embodiment of the present invention, the viscosity of the branched polysiloxane is 100 mPa·s to 100000 mPa·s at 25°C.

[0041] In another embodiment of the present invention, the molecular formula of the branched polysiloxane is (R 1 2R 2 SiO)-((CH3)2SiO) a -(CH3R 2 SiO) b -(OSiR 1 2R 2 ), where each R 1 Each R is independently selected from vinyl, phenyl, hydroxyl, hydrogen, alkoxy or hydrocarbon groups having 1 to 10 carbon atoms. 2 The present invention is selected from alkenyl groups having 1 to 10 carbon atoms, and a and b are integers in the range of 1 to 2500.

[0042] In a preferred embodiment of the present invention, the molecular formula of the branched polysiloxane is (R 1 2R2 SiO)-((CH3)2SiO) a -(CH3R 2 SiO) b -(OSiR 1 2R 2 ), wherein the R 1 is selected from methyl or vinyl, R 2 Selected from vinyl, a, b is an integer from 1 to 2500, wherein the vinyl content is 0.05% to 0.31%.

[0043] In another embodiment of the present invention, the additive is at least one of nano-silicon dioxide, nano-titanium dioxide or nano-aluminum oxide.

[0044] Additives can be used to physically adsorb residual small molecules and construct a physical cross-linking network to avoid transfer to the adhered object in a high temperature and high humidity environment.

[0045] In another embodiment of the present invention, the BET specific surface area of ​​the additive is 50 to 500 m 2 / g.

[0046] This specific surface area range is selected to achieve the best physical adsorption effect on small pairs.

[0047] In another embodiment of the present invention, the molecular formula of the MQ resin is (R 1 3SiO 1 / 2 ) m (SiO 4 / 2 ) n , where the ratio of m:n is 0.6 to 1.2.

[0048] In another embodiment of the present invention, the ratio of m:n is 0.6-0.9.

[0049] In another embodiment of the present invention, the weight average molecular weight of the MQ resin is 1,000 to 20,000.

[0050] In another embodiment of the present invention, the weight average molecular weight of the MQ resin is 3000-9000.

[0051] In another embodiment of the present invention, the MQ resin has a silanol content of 0.01% to 5% (mass fraction).

[0052] In another embodiment of the present invention, the MQ resin has a silanol content of 0.05% to 3.5% (mass fraction).

[0053] In another embodiment of the present invention, the MQ resin is solid powder.

[0054] By selecting the above MQ resin, the peeling strength of the pressure-sensitive adhesive is higher.

[0055] In another embodiment of the present invention, the cross-linking agent is at least one of linear, branched or cyclic hydrogen-containing polyorganohydrogensiloxane.

[0056] In another embodiment of the present invention, each molecular chain of the cross-linking agent contains at least two or three silicon-bonded hydrogen atoms (ie, Si-H), and the content of Si-H (ie, hydrogen content) is 0.01%-1.60%.

[0057] In another embodiment of the present invention, the viscosity of the cross-linking agent at 25° C. is 10 mPa·s to 1000 mPa·s; preferably, the viscosity is 20 mPa·s to 300 mPa·s.

[0058] In another embodiment of the present invention, the inhibitor is at least one of 3-methyl-2-butynol, 1-ethynyl-cyclohexanol, diallyl maleate, and 3,5-dimethyl-1-hexyn-3-ol.

[0059] In another embodiment of the present invention, a method for preparing the above-mentioned solvent-free silicone pressure-sensitive adhesive is also provided, comprising:

[0060] Add 100 parts of methyl MQ silicone resin, 30-150 parts of linear polysiloxane, 10-180 parts of branched polysiloxane and 1-5 parts of additives and mix evenly, increase the temperature, and reduce the pressure to remove low molecular weight;

[0061] 1 to 10 parts of a cross-linking agent are added, and after cooling, 0.1 to 1 part of an inhibitor is added, and mixed evenly to obtain the pressure-sensitive adhesive.

[0062] The invention can control the amount of small molecular weight in the system by mixing silicone resin, polysiloxane and additives at high temperature and performing vacuum degassing treatment, thereby solving the problem of ghosting caused by the transfer of pressure-sensitive adhesive to adhered objects under high temperature and high humidity environment.

[0063] In another embodiment of the present invention, the temperature rising condition is 90° C. to 180° C., the time for removing low molecular weight is 1 h to 5 h, and the decompression pressure is -0.09 to -0.1 MPa.

[0064] In another embodiment of the present invention, a method for preparing a solvent-free silicone pressure-sensitive adhesive product is provided, comprising uniformly mixing the prepared silicone pressure-sensitive adhesive with an anchoring agent and a catalyst, coating the mixture on a substrate and curing the mixture to obtain the silicone pressure-sensitive adhesive product.

[0065] In another embodiment of the present invention, the catalyst is a platinum metal catalyst.

[0066] In another embodiment of the present invention, the coating thickness is 10 μm to 50 μm.

[0067] In another embodiment of the present invention, the curing conditions are: temperature 110° C. to 150° C., time 2 to 5 min.

[0068] The product prepared by the pressure-sensitive adhesive of the present invention has a transparent appearance, high colloid cohesive strength, good peeling force stability, no residual adhesive and ghosting under high temperature and high humidity, and can be applied to the manufacturing process and shipment protection process of electronic products. Specific implementation method:

[0070] Example 1

[0071] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.75 (SiO 4 / 2 ), Mw is 5000, silanol content is 0.05%), 100 parts of polydimethylsiloxane with a viscosity of 1000mPa·s and an alkenyl terminal group and 40 parts of polysiloxane with a viscosity of 5000mPa·s, an alkenyl terminal group and a methyl and alkenyl side group with a vinyl content of 0.25%, are uniformly stirred with 2 parts of nano-silica with a BET surface area of ​​200, heated to 120°C, and then reduced to -0.1MPa for 3h to remove the solvent to prepare the mixture, and then 4 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content (Si-H) of 0.8% and a viscosity of 30mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol are added to obtain the main silicone pressure-sensitive adhesive.

[0072] Example 2

[0073] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.8 (SiO 4 / 2 ), Mw is 4500, silanol content is 0.5%)), 150 parts of polydimethylsiloxane with a viscosity of 2000mPa·s and an alkenyl terminal group and 10 parts of polysiloxane with a viscosity of 100000mPa·s, an alkenyl terminal group and a methyl and alkenyl side group with a vinyl content of 0.065%, are stirred evenly with 1 part of silica with a BET surface area of ​​300, heated to 160°C, and then reduced to -0.1MPa for 5h to remove the solvent to prepare the mixture, and then 3 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 1.56% and a viscosity of 20mPa·s, 0.2 parts of 3-methyl-2-butynol and 0.1 parts of 1-ethynyl-cyclohexanol are added to obtain the main silicone pressure-sensitive adhesive.

[0074] Example 3

[0075] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.6 (SiO 4 / 2 ), Mw is 8000, silanol content is 1%), 30 parts of polydimethylsiloxane with a viscosity of 100000mPa·s and an alkenyl terminal group and 180 parts of polysiloxane with a viscosity of 1000mPa·s and an alkenyl terminal group and a vinyl content of 0.3%, are mixed evenly with 1 part of silicon dioxide with a BET surface area of ​​300 and 2 parts of nano titanium dioxide with a BET surface area of ​​50, heated to 90°C, reduced pressure to -0.1MPa and removed for 2h to remove the solvent to prepare the mixture, and then 5 parts of a crosslinking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 1.2% and a viscosity of 80mPa·s, 0.2 parts of methyl butynol and 0.1 parts of diallyl maleate are added to obtain a main silicone pressure-sensitive adhesive.

[0076] Example 4

[0077] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.9 (SiO 4 / 2 ), Mw is 3000, silanol content is 0.03%), 120 parts of polydimethylsiloxane with a viscosity of 500mPa·s and alkenyl terminal groups, and 25 parts of polysiloxane with a viscosity of 50000mPa·s, alkenyl terminal groups, methyl and alkenyl side groups, with a vinyl content of 0.1%, are mixed evenly with 3 parts of silicon dioxide with a BET surface area of ​​300 and 2 parts of nano titanium dioxide with a BET surface area of ​​50, and heated to 100 ℃, and then reduce the pressure to -0.1 MPa for 1h to remove the prepared mixture of the solvent, and then add 2 parts of a cross-linking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 1.56% and a viscosity of 20 mPa·s and 8 parts of a cross-linking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 0.05% and a viscosity of 300 mPa·s, as well as 0.3 parts of diallyl maleate and 0.1 parts of 3,5-dimethyl-1-hexyn-3-ol to obtain a silicone pressure-sensitive adhesive main adhesive.

[0078] Example 5

[0079] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.9 (SiO 4 / 2), Mw is 3000, silanol content is 0.03%), 120 parts of polydimethylsiloxane with a viscosity of 500mPa·s and alkenyl terminal groups, and 25 parts of polysiloxane with a viscosity of 50000mPa·s and alkenyl terminal groups and methyl and alkenyl side groups with a vinyl content of 0.1%, are mixed with 1 part of silicon dioxide with a BET surface area of ​​300 and 2 parts of nano-alumina with a BET surface area of ​​200, and heated to 100 ℃, and then reduce the pressure to -0.08 MPa for 1 hour to remove the prepared mixture of the solvent, and then add 2 parts of a cross-linking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 1.56% and a viscosity of 20 mPa·s and 3 parts of a cross-linking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 0.05% and a viscosity of 300 mPa·s, as well as 0.3 parts of diallyl maleate and 0.1 parts of 3,5-dimethyl-1-hexyn-3-ol to obtain a silicone pressure-sensitive adhesive main adhesive.

[0080] Example 6

[0081] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.75 (SiO 4 / 2 ), Mw is 5000, silanol content is 0.05%), 130 parts of polydimethylsiloxane with a viscosity of 1000mPa·s and alkenyl terminal groups, and 25 parts of polysiloxane with a viscosity of 10000mPa·s, alkenyl terminal groups, methyl and alkenyl side groups, with a vinyl content of 0.15%, are stirred evenly with 0.5 parts of silicon dioxide with a BET surface area of ​​300 and 0.5 parts of nano-alumina with a BET surface area of ​​200, After heating to 180°C, the pressure was reduced to -0.1MPa for 5h to remove the solvent to prepare the mixture, and then 3 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 1.56% and a viscosity of 20mPa·s and 5 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 0.1% and a viscosity of 100mPa·s were added, as well as 0.5 parts of methylbutynol and 0.5 parts of 1-ethynyl-cyclohexanol to obtain the silicone pressure-sensitive adhesive main adhesive.

[0082] Example 7

[0083] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 1.2 (SiO 4 / 2), Mw is 9000, silanol content is 3.5%), 100 parts of polydimethylsiloxane with a viscosity of 100mPa·s and an alkenyl terminal group and 40 parts of polysiloxane with a viscosity of 100mPa·s, an alkenyl terminal group and a methyl and alkenyl side group with a vinyl content of 0.05%, are stirred evenly with 2 parts of nano-silica with a BET surface area of ​​500, heated to 120°C, and then reduced to -0.1MPa for 3h to remove the solvent to prepare the mixture, and then 4 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 0.01% and a viscosity of 1000mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol are added to obtain the main silicone pressure-sensitive adhesive.

[0084] Comparative Example 1

[0085] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.75 (SiO 4 / 2 ), Mw is 5000, silanol content is 0.05%), 100 parts of polydimethylsiloxane with a viscosity of 1000mPa·s and an alkenyl terminal group and 40 parts of polysiloxane with a viscosity of 5000mPa·s, an alkenyl terminal group and a methyl and alkenyl side group and a vinyl content of 0.25%, after heating to 120°C, reducing the pressure to -0.1MPa for 3h to remove the solvent to prepare the mixture, and then adding 4 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 0.8% and a viscosity of 30mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol to obtain the main silicone pressure-sensitive adhesive.

[0086] Comparative Example 2

[0087] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.75 (SiO 4 / 2 ), Mw is 5000, silanol content is 0.05%), 140 parts of polydimethylsiloxane with a viscosity of 1000mPa·s and an alkenyl terminal group are uniformly stirred with 2 parts of nano-silica with a BET surface area of ​​200, heated to 120°C, and then reduced to -0.1MPa for 3h to remove the prepared mixture of the solvent, and then 4 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 0.8% and a viscosity of 30mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol are added to obtain the main silicone pressure-sensitive adhesive.

[0088] Comparative Example 3

[0089] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.75 (SiO 4 / 2 ), Mw is 5000, silanol content is 0.05%), 140 parts of polysiloxane with a vinyl content of 0.25%, a viscosity of 5000mPa·s, an alkenyl terminal group, and a methyl and alkenyl side group, are mixed evenly with 2 parts of nano-silica with a BET surface area of ​​200, heated to 120°C, and then reduced to -0.1MPa for 3h to remove the solvent to prepare the mixture, and then 4 parts of a cross-linking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 0.8% and a viscosity of 30mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol are added to obtain the main silicone pressure-sensitive adhesive.

[0090] Comparative Example 4

[0091] Preparation of the main adhesive of the silicone pressure-sensitive adhesive: In a 500mL open reactor, add 100 parts of MQ silicone resin ((CH3)3SiO1 / 2)0.75(SiO4 / 2), Mw of 5000, silanol content of 0.05%), 100 parts of polydimethylsiloxane with a viscosity of 1000mPa·s and an alkenyl terminal group, and 40 parts of polysiloxane with a viscosity of 5000mPa·s, an alkenyl terminal group, and a methyl and alkenyl side group, and stir evenly with 2 parts of silicon dioxide with a BET surface area of ​​200. After heating to 120°C and keeping warm for 3h, add 4 parts of a cross-linking agent (straight-chain polymethyl hydrogen siloxane) with a hydrogen content of 0.8% and a viscosity of 30mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol to obtain the main adhesive of the silicone pressure-sensitive adhesive.

[0092] Comparative Example 5

[0093] Preparation of silicone pressure-sensitive adhesive master: Add 100 parts of MQ silicone resin ((CH3)3SiO 1 / 2 ) 0.75 (SiO 4 / 2 ), Mw is 5000, silanol content is 0.05%), 20 parts of polydimethylsiloxane with a viscosity of 1000mPa·s and an alkenyl terminal group and 190 parts of polysiloxane with a viscosity of 5000mPa·s, an alkenyl terminal group and a methyl and alkenyl side group with a vinyl content of 0.25%, are stirred evenly with 7 parts of silica with a BET surface area of ​​200, heated to 120°C, and then reduced to -0.1MPa for 3h to remove the solvent to prepare the mixture, and then 4 parts of a cross-linking agent (straight-chain polymethylhydrogensiloxane) with a hydrogen content of 0.8% and a viscosity of 30mPa·s and 0.5 parts of 1-ethynyl-cyclohexanol are added to obtain the main silicone pressure-sensitive adhesive.

[0094] Comparative Example 6

[0095] 100 parts of conventional silicone pressure-sensitive adhesive (commercially available product) were added to a four-necked flask and fully dispersed and mixed, and then a crosslinking agent, an anchoring agent and a catalyst were added in sequence at intervals of 5 minutes, and the dispersion was continued for 20 minutes.

[0096] The silicone pressure-sensitive adhesive obtained in the embodiments and comparative examples was used to prepare a silicone protective film. The specific preparation process was as follows: 100 parts of the pressure-sensitive adhesive obtained in the embodiments and comparative examples were evenly mixed with 1 part of Custer platinum catalyst (platinum concentration was 5000 ppm), and coated on a PET film with a coater to a thickness of 20 μm. The adhesive layer was cured at 150° C. for 2 min to finally obtain a pressure-sensitive adhesive product.

[0097] The main adhesives and pressure-sensitive adhesive products obtained in the embodiments and comparative examples were subjected to various tests, as follows:

[0098] 1) The main adhesive obtained in the embodiment and the comparative example was subjected to a viscosity test, specifically, the viscosity at 25° C. was tested using a viscometer from BROOKFIELD, USA, and the change in viscosity after 15 days was observed.

[0099] 2) The adhesive properties of pressure-sensitive adhesive products were tested using the test method for adhesive tape peel strength of GBT2792-1998. The results were expressed in N / 25mm, and the data changes after aging at 80°C for 24 hours were tested.

[0100] 3) 100-grid test: apply the protective film, tear off the composite film, boil in boiling water for 2 hours, then use a 100-grid knife to cut 100 grids, and use an eraser to wipe 20 times back and forth. Debonding is NG;

[0101] 4) Silicon migration test: the protective film is removed and the composite film is attached to the copper foil. It is stored under double 85 conditions (85°C / 85%RH) for 3 days, and the change of dyne value on the copper foil surface is tested with a dyne pen.

[0102] The above test results are shown in Table 1.

[0103] Table 1 Test results of embodiments and comparative examples

[0104]

[0105]

[0106] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A solvent-free silicone pressure-sensitive adhesive, characterized in that: The invention comprises, by weight, 100 parts of methyl MQ silicone resin, 30 to 150 parts of linear polysiloxane, 10 to 180 parts of branched polysiloxane, 1 to 5 parts of additives, 1 to 10 parts of crosslinking agents and 0.1 to 1 part of inhibitors.

2. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The linear polysiloxane is: a polysiloxane whose terminal group is an alkenyl group and the side group is a methyl group; And / or the branched polysiloxane is a polysiloxane whose terminal group is an alkenyl group and whose side groups are methyl and alkenyl groups.

3. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The linear polysiloxane has a viscosity of 100 mPa·s to 100000 mPa·s at 25° C.; And / or the molecular formula of the linear polysiloxane is (R 1 2R 2 SiO)-((CH3)2SiO) a -(OSiR 1 2R 2 ), where each R 1 Each R is independently selected from vinyl, phenyl, hydroxyl, hydrogen, alkoxy or hydrocarbon groups having 1 to 10 carbon atoms. 2 The present invention is selected from alkenyl groups having 1 to 10 carbon atoms, and a is an integer from 1 to 2500; preferably, a is an integer from 500 to 2500.

4. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The viscosity of the branched polysiloxane is 100 mPa·s to 100000 mPa·s at 25° C.; And / or the molecular formula of the branched polysiloxane is (R 1 2R 2 SiO)-((CH3)2SiO) a -(CH3R 2 SiO) b -(OSiR 1 2R 2 ), where each R 1 Each R is independently selected from vinyl, phenyl, hydroxyl, hydrogen, alkoxy or hydrocarbon groups having 1 to 10 carbon atoms. 2 is selected from alkenyl groups having 1 to 10 carbon atoms, a, b is an integer from 1 to 2500; Preferably, the R 1 is selected from methyl or vinyl, R 2 Selected from vinyl, wherein the vinyl content is 0.05% to 0.31%.

5. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The additive is at least one of nano silicon dioxide, nano titanium dioxide or nano aluminum oxide; Preferably, the BET specific surface area of ​​the additive is 50 to 500 m 2 / g.

6. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The molecular formula of the MQ resin is (R 1 3SiO 1 / 2 ) m (SiO 4 / 2 ) n , where the ratio of m:n is 0.6 to 1.2; More preferably, the ratio of m:n is 0.6 to 0.9; Preferably, the weight average molecular weight of the MQ resin is 1000 to 20000. More preferably, the weight average molecular weight of the MQ resin is 3000-9000.

7. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The MQ resin has a silanol content of 0.01% to 5%; More preferably, the MQ resin has a silanol content of 0.05% to 3.5%.

8. The solvent-free silicone pressure-sensitive adhesive according to claim 1, characterized in that: The cross-linking agent is at least one of linear, branched or cyclic hydrogen-containing polysiloxane; And / or each molecular chain of the cross-linking agent contains at least two or three Si-H groups, and the hydrogen content is 0.01-1.60%. And / or the viscosity of the cross-linking agent at 25° C. is 10 mPa·s to 1000 mPa·s; preferably, the viscosity is 20 mPa·s to 300 mPa·s. And / or the inhibitor is at least one of 3-methyl-2-butynol, 1-ethynyl-cyclohexanol, diallyl maleate, and 3,5-dimethyl-1-hexyn-3-ol.

9. A method for preparing the solvent-free organosilicon pressure-sensitive adhesive according to any one of claims 1 to 8, characterized in that: include: Add 100 parts of methyl MQ silicone resin, 30-150 parts of linear polysiloxane, 10-180 parts of branched polysiloxane and 1-5 parts of additives and mix evenly, increase the temperature, and reduce the pressure to remove low molecular weight; 1 to 10 parts of a cross-linking agent are added, and after cooling, 0.1 to 1 part of an inhibitor is added, and mixed evenly to obtain the pressure-sensitive adhesive.

10. The preparation method according to claim 9, characterized in that: The temperature rising condition is 90° C. to 180° C., the time for removing low molecular weight is 1 h to 5 h, and the decompression pressure is -0.09 to -0.1 MPa.

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