Silicone-modified polyacrylate pressure-sensitive adhesive and preparation method thereof

Abstract

The present invention relates to an organosilicon-modified polyacrylic acid pressure-sensitive adhesive and a preparation method. The organosilicon-modified polyacrylic acid pressure-sensitive adhesive comprises, by weight, a polyacrylate pressure-sensitive adhesive, an organosilicon pressure-sensitive adhesive, and an organosilicon-modified acrylate copolymer. The present invention uses the organosilicon-modified acrylate copolymer as a phase stability compatibilizer, thereby significantly improving the performance stability of a blend of the organosilicon pressure-sensitive adhesive and the polyacrylate pressure-sensitive adhesive.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure-sensitive adhesives including MQ silicone resin, in particular to an organosilicon-modified polyacrylate pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] Acrylic and silicone pressure-sensitive adhesives are widely used in a variety of electronic, medical, and industrial products. However, each has distinct advantages and disadvantages. Acrylic pressure-sensitive adhesives have a relatively high polarity, strong bonding ability, and low material cost, but they suffer from poor high-temperature resistance. Silicone pressure-sensitive adhesives have a relatively low polarity and good high-temperature resistance, but they also suffer from lower bonding performance and a higher material cost. Blending silicone and acrylate pressure-sensitive adhesives to complement their respective strengths and weaknesses has important practical applications. However, blending silicone and acrylate pressure-sensitive adhesives is thermodynamically unstable. Therefore, adhesive tapes prepared using these blends will gradually separate during use, resulting in increasingly poor performance.

[0003] U.S. patent applications Nos. 5,474,783, 6,024,976, 6,221,383, 6,465,004, and 6,638,528 disclose various physical mixtures of acrylate pressure-sensitive adhesives and silicone pressure-sensitive adhesives for transdermal drug delivery systems. However, these two pressure-sensitive adhesives are completely incompatible thermodynamically, resulting in physical mixtures that not only severely degrade the performance of the pressure-sensitive adhesives but also exhibit extremely unstable properties, potentially leading to phase separation during production, transportation, and storage. This phase separation structure also changes over time, temperature, and other conditions, leading to instability in the quality and performance of the final product, severely limiting the practicality of these methods.

[0004] Japanese patent application JP60197780A also reports a physical blend of an acrylate pressure-sensitive adhesive and a silicone pressure-sensitive adhesive in an organic solvent to obtain a silicone-modified acrylate pressure-sensitive adhesive. However, the acrylate and silicone pressure-sensitive adhesive blend is also prone to phase separation, resulting in poor product stability.

[0005] JP 62-295982 describes a chemical blending method for crosslinking silicone and acrylate pressure-sensitive adhesives using polyurethane and / or polyisocyanate crosslinkers. The main drawbacks of this system are the short shelf life of the product formulation and poor product quality stability. The crosslinking reaction begins immediately after the crosslinker is added to the silicone and acrylate blends, causing the degree of phase separation between the silicone and acrylate blends to vary with storage time.

[0006] U.S. Patents 5,464,6659 and 5,624,763 disclose methods for preparing silicone-modified acrylate pressure-sensitive adhesive tapes for shock-absorbing applications. The method involves dissolving a solid silicone pressure-sensitive adhesive in a mixture of acrylic monomers, a photoinitiator, and a crosslinker, coating the adhesive on a substrate, and then subjecting the coating to UV radiation for polymerization or curing after drying. The main drawback of this method remains the short shelf life of the product formulation. The homogeneous mixture of the silicone pressure-sensitive adhesive, acrylic monomers, photoinitiator, and crosslinker undergoes phase separation after 12 hours at room temperature. Another significant drawback is that the UV radiation polymerization or curing process must be carried out in a substantially oxygen-free or nitrogen-free atmosphere, resulting in high production costs, more complex processes, and a limited shelf life for the formulated material.

[0007] As mentioned above, the existing preparation method of the blend of silicone pressure-sensitive adhesive and acrylate pressure-sensitive adhesive is prone to phase separation, resulting in instability of the final product, and needs further improvement. Summary of the Invention

[0008] The purpose of the present invention is to effectively improve the stability of the blend and facilitate large-scale industrial production.

[0009] In order to achieve the above object, the present invention provides a silicone-modified polyacrylate pressure-sensitive adhesive, which comprises the following components, calculated by weight:

[0010]

[0011] Preferably, the sum of the mass percentages of the components is 100%.

[0012] The organosilicon-modified polyacrylate pressure-sensitive adhesive of the present invention uses an organosilicon-modified acrylate copolymer as a compatibilizer for polyacrylate pressure-sensitive adhesive and organosilicon pressure-sensitive adhesive. The organosilicon-modified acrylate copolymer contains both acrylic acid and organosilicon, and compatibilizes the polyacrylate pressure-sensitive adhesive and the organosilicon pressure-sensitive adhesive together, plays a compatibilizing role, improves the compatibility of the polyacrylate pressure-sensitive adhesive and the organosilicon pressure-sensitive adhesive, and converts the incompatible polyacrylate pressure-sensitive adhesive and the organosilicon pressure-sensitive adhesive into a stable modified pressure-sensitive adhesive.

[0013] In some embodiments of the present invention, the silicone-modified polyacrylate pressure-sensitive adhesive comprises the following components, calculated in parts by mass:

[0014]

[0015] Preferably, the sum of the mass percentages of the components is 100%.

[0016] In some embodiments of the present invention, the silicone-modified polyacrylate pressure-sensitive adhesive comprises the following components, calculated in parts by mass:

[0017]

[0018] Preferably, the sum of the mass percentages of the components is 100%.

[0019] The silicone-modified acrylate copolymer in the silicone-modified polyacrylate pressure-sensitive adhesive of the present invention is a copolymer, which includes silicone that is compatible with the silicone pressure-sensitive adhesive and also includes acrylic monomer segments that are compatible with the polyacrylate pressure-sensitive adhesive. It microscopically compatibilizes the two incompatible silicone pressure-sensitive adhesives and polyacrylate pressure-sensitive adhesives together, acting as a compatibilizer to increase compatibility.

[0020] In some embodiments of the present invention, the organosilicon-modified acrylate copolymer comprises the following components, calculated in parts by mass:

[0021]

[0022] Preferably, the sum of the mass percentages of the components is 100%.

[0023] The polymerized silicone oil of the present invention increases compatibility with an organic silicone pressure-sensitive adhesive, and the (meth)acrylate alkyl ester and the monomer with a polar functional group increase compatibility with a polyacrylate pressure-sensitive adhesive. The polymerized silicone oil undergoes a copolymerization reaction with the (meth)acrylate alkyl ester and the monomer with a polar functional group through the polymerizable functional group at the chain end thereof to form a copolymer with a special structure of the polymerized silicone oil grafted with the polyacrylate, thereby increasing the compatibility between the organic silicone pressure-sensitive adhesive and the polyacrylate pressure-sensitive adhesive.

[0024] The present application utilizes the compatibilizing effect of graft copolymerization of polymerized silicone oil with (meth) alkyl acrylate and monomers with polar functional groups to increase the compatibility of polyacrylate pressure-sensitive adhesive and silicone pressure-sensitive adhesive, avoids phase separation of silicone-modified polyacrylate pressure-sensitive adhesive, and makes the silicone-modified polyacrylate pressure-sensitive adhesive resistant to high temperatures and has increased peel strength.

[0025] In some embodiments of the present invention, the polymerized silicone oil includes (meth)acrylic silicone oil and / or vinyl silicone oil. Preferably, the polymerized silicone oil is vinyl silicone oil, and its polydimethylsilane main chain has vinyl groups at both ends. The vinyl group reacts relatively slowly and cannot polymerize with itself, but can copolymerize with acrylic monomers.

[0026] Prior art typically uses vinyl silicone oil as the base material for silicone rubber, but the vinyl silicone oil of the present invention is compatible with silicone pressure-sensitive adhesives. The silicone pressure-sensitive adhesive is held in place by the same (meth)acrylate and polyacrylate pressure-sensitive adhesive segments. The polyacrylate pressure-sensitive adhesive is held in place by chemically grafting the vinyl silicone oil onto the copolymerized segments of the (meth)acrylate and a monomer with a polar functional group. Vinyl silicone oil is a commonly used silicone with low cost. (Meth)acrylate-based silicone oil can also be used, but it is very expensive. Furthermore, vinyl silicone oil has relatively low reactivity, making it easier to control the degree of crosslinking and avoid gel formation when synthesizing silicone-modified polyacrylate pressure-sensitive adhesives.

[0027] In some embodiments of the present invention, the organosilicon-modified acrylate copolymer comprises the following components, calculated in parts by mass:

[0028]

[0029] Preferably, the sum of the mass percentages of the components is 100%.

[0030] In some embodiments of the present invention, the number of carbon atoms of the alkyl group in the (meth)acrylate in the silicone-modified acrylate copolymer is indivual.

[0031] In some embodiments of the present invention, the alkyl (meth)acrylate and the monomer having a polar functional group include one or more of acrylic acid, 2-ethylhexyl acrylate, methyl methacrylate, and glycidyl methacrylate.

[0032] In some embodiments of the present invention, the thermal initiator in the organosilicon-modified acrylate copolymer is a peroxide initiator and / or an azo initiator.

[0033] The role of thermal initiators in silicone-modified acrylate copolymers is to promote the thermal polymerization of alkyl (meth)acrylates and monomers with polar functional groups. First, the thermal initiator decomposes to form primary free radicals, which then add to the monomers to form monomer free radicals. This monomer free radical then opens another double bond and adds to another monomer, forming new free radicals that form more structural units. This process continues, ultimately forming a high-molecular-weight copolymer. For example, peroxides generate free radicals at high temperatures, which initiate free radical polymerization of the monomers during the polymerization process.

[0034] In some embodiments of the present invention, the diluent in the organosilicon-modified acrylate copolymer is one or more organic solvents selected from aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons.

[0035] In some embodiments of the present invention, the viscosity of the vinyl silicone oil is The viscosity of the vinyl silicone oil is related to its molecular weight. If the molecular weight is too high, the chain segments of the vinyl silicone oil are very long, making it difficult to graft with acrylic acid during polymerization. If the molecular weight is too low, the chain segments are too short and cannot bind to the silicone pressure-sensitive adhesive. Vinyl silicone oil and acrylic acid are incompatible. Polymerization in solution chemically connects them together, resulting in short chains that easily bind to the acrylic medium but not to the silicone pressure-sensitive adhesive, resulting in poor compatibilization. If the molecular weight is too high, grafting is difficult during copolymerization.

[0036] In some embodiments of the present invention, the polyacrylate pressure-sensitive adhesive comprises the following components, calculated in parts by mass:

[0037]

[0038] Preferably, the sum of the mass percentages of the components is 100%.

[0039] In some embodiments of the present invention, the polyacrylate pressure-sensitive adhesive comprises the following components, calculated in parts by mass:

[0040]

[0041] Preferably, the sum of the mass percentages of the components is 100%.

[0042] In some embodiments of the present invention, the number of carbon atoms of the alkyl group in the (meth)acrylate monomer in the polyacrylate pressure-sensitive adhesive is

[0043] In some embodiments of the present invention, the thermal initiator in the polyacrylate pressure-sensitive adhesive is a peroxide initiator and / or an azo initiator.

[0044] In some embodiments of the present invention, the diluent in the polyacrylate pressure-sensitive adhesive is one or more of alkanes, alkyl esters, aromatics, and alkanols.

[0045] In some embodiments of the present invention, the silicone pressure-sensitive adhesive comprises the following components, calculated in parts by mass:

[0046]

[0047] Preferably, the sum of the mass percentages of the components is 100%.

[0048] In some embodiments of the present invention, the MQ resin is a copolymer composed of Q siloxy units (SiO3 / 2,) and M siloxy units ((CH3)3SiO2 / 2), preferably, the ratio of the Q siloxy units (SiO3 / 2,) and the M siloxy units ((CH3)3SiO2 / 2) is

[0049] In some embodiments of the present invention, the viscosity of the dimethyl silicone rubber at 25°C is viscosity.

[0050] In some embodiments of the present invention, the thermal crosslinking agent is a peroxide initiator.

[0051] Thermal crosslinkers work by abstracting hydrogen radicals to generate two free radicals, which then couple to produce crosslinks. For example, at high temperatures, BPO (benzoyl peroxide) first decomposes to produce a large number of free radicals. The free radicals remove hydrogen from the methyl groups of the silica gel chain, causing them to form new methyl radicals. The two new methyl radicals on the silica gel chain couple to form chemical crosslinks between the silica gel chains. Thermal crosslinkers can also use benzoyl dichloride or other peroxides, but their cost is higher than that of benzoyl peroxide.

[0052] In some embodiments of the present invention, the diluent is one or more of aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons.

[0053] The present invention also provides a method for preparing a silicone-modified polyacrylate pressure-sensitive adhesive, comprising:

[0054] Mixing polyacrylate pressure-sensitive adhesive, silicone pressure-sensitive adhesive and silicone-modified acrylate copolymer to obtain a mixed adhesive;

[0055] The mixed adhesive is coated on a substrate and dried to obtain an organosilicon-modified polyacrylate pressure-sensitive adhesive.

[0056] In the preparation method of the organosilicon-modified polyacrylate pressure-sensitive adhesive of the present invention, an organosilicon-modified acrylate copolymer is used as a compatibilizer, which significantly improves the phase stability and performance stability of the blend of the organosilicon pressure-sensitive adhesive and the polyacrylate pressure-sensitive adhesive. This preparation method not only has greater flexibility and a simpler application process, but also has lower technical implementation costs, facilitating large-scale industrial production.

[0057] In some embodiments of the present invention, the method for preparing the organosilicon-modified acrylate copolymer comprises:

[0058] Add the first batch of materials to the reaction device, stir and heat, the first batch of materials including the first part of diluent, the first part of polymerized silicone oil, the first part of (meth) acrylate and the monomer with polar functional group and the first part of thermal initiator; preferably, in the stirring and heating step, stir and heat to Preferably, the reaction time is

[0059] When the first batch of materials in the reaction device begins to reflux, the second batch of materials is added and the reflux temperature is maintained. The second batch of materials includes a second portion of alkyl (meth)acrylate and a monomer with a polar functional group, a second portion of polymerized silicone oil, a second portion of a thermal initiator, and a second portion of a diluent; preferably, the second batch of materials is added dropwise, and more preferably, the addition time is Preferably, maintain reflux temperature

[0060] Add the third batch of materials, and keep the reflux temperature set time again, cool down and discharge, and obtain the organosilicon modified acrylate copolymer, wherein the third batch of materials includes the third part of thermal initiator and the third part of diluent; preferably, keep the reflux temperature set time again

[0061] Among them, the first part of diluent accounts for % of the total diluent The second part of diluent accounts for the total amount of diluent The first part of the (meth) alkyl acrylate and the monomer with polar functional group accounts for the total amount of the (meth) alkyl acrylate and the monomer with polar functional group. The first part of thermal initiator accounts for the total amount of thermal initiator The second part of thermal initiator accounts for the total amount of thermal initiator The first part of polymerized silicone oil accounts for the total amount of vinyl silicone oil

[0062] The reaction device can be a three- or four-mouth polymerization reaction bottle or polymerization reaction kettle.

[0063] The first part of diluent accounts for the total amount of diluent Sufficient to dissolve vinyl silicone oil, the amount of diluent initially added and the total amount of diluent added during the preparation process mainly depend on the molecular weight of the silicone-modified acrylate copolymer. If the molecular weight is small, more diluent should be added.

[0064] The initial addition amount and total addition amount of the thermal initiator mainly depend on the viscosity of the organosilicon-modified acrylate copolymer. If the viscosity is low, more thermal initiator is added; if the viscosity is high, less thermal initiator is added. The initial addition amount and total addition amount of the diluent and thermal initiator have an impact on the viscosity and molecular weight of the organosilicon-modified acrylate copolymer. For example, if it is necessary to prepare an organosilicon-modified acrylate copolymer with low viscosity and high molecular weight, the initial addition amount of the diluent and thermal initiator is small. Finally, if the viscosity is high, diluent is added to dilute it to prepare an organosilicon-modified acrylate copolymer with low viscosity and high molecular weight.

[0065] In the preparation method of the above-mentioned organosilicon-modified acrylate copolymer, polymerized silicone oil is first added. Polymerized silicone oil reacts relatively slowly and is not easy to react. Adding it to the first batch of materials allows the polymerized silicone oil to have more opportunities to copolymerize.

[0066] In the preparation method of the organosilicon-modified acrylate copolymer of the present invention, the first batch of materials has the following heating conditions: the first condition is to add only a diluent and a polymerized silicone oil; the polymerized silicone oil reacts relatively slowly and is not easy to react, and its addition to the first batch of materials allows the polymerized silicone oil to have more opportunities for copolymerization; the second condition is to add a diluent, a polymerized silicone oil, an alkyl (meth)acrylate, and a monomer with a polar functional group; in order to increase the monomer, a portion of the alkyl (meth)acrylate and the monomer with a polar functional group are added; the reaction time of the polymerizable functional groups of the polymerized silicone oil and the monomer is the longest, which increases the possibility of copolymerization; the third condition is to add a diluent, a polymerized silicone oil, and a thermal initiator; during the heating process, the thermal initiator thermally decomposes, which plays a role in initiating and accelerating the polymerization reaction of the subsequently added polymerized silicone oil and monomer; the fourth condition is to add a diluent, a polymerized silicone oil, a thermal initiator, an alkyl (meth)acrylate, and a monomer with a polar functional group; the reaction time of the polymerizable functional groups of the polymerized silicone oil and the monomer is the longest, which increases the possibility of copolymerization and the thermal initiator decomposes to promote the polymerization reaction.

[0067] In some embodiments of the present invention, the step of cooling and discharging includes: adding a diluent to adjust the solid content of the organosilicon-modified acrylate copolymer after cooling, and discharging after stirring.

[0068] In some embodiments of the present invention, the method for preparing the polyacrylate pressure-sensitive adhesive includes:

[0069] Add the first batch of materials to the reaction device, stir and heat up, the first batch of materials including the first part of diluent, the first part of (meth) alkyl acrylate and the monomer with polar functional group and the first part of thermal initiator; preferably, in the step of stirring and heating up: stirring and heating to reaction

[0070] When the first batch of materials in the reaction device begins to reflux, the second batch of materials is added and the reflux temperature is maintained. The second batch of materials includes a second portion of alkyl (meth)acrylate and a monomer with a polar functional group, a second portion of a thermal initiator, and a second portion of a diluent; preferably, the second batch of materials is added dropwise, and more preferably, the addition time is Preferably, maintain reflux temperature

[0071] Cooling and discharging to obtain polyacrylate pressure-sensitive adhesive;

[0072] Among them, the first part of diluent accounts for % of the total diluent The first part of the (meth) alkyl acrylate and the monomer with polar functional group accounts for the total amount of the (meth) alkyl acrylate and the monomer with polar functional group. The first part of thermal initiator accounts for the total amount of thermal initiator The second part of thermal initiator accounts for the total amount of thermal initiator

[0073] In some embodiments of the present invention, before the step of cooling and discharging, the step further includes: adding a third batch of materials and maintaining the reflux temperature for a set time again, wherein the third batch of materials includes a third portion of thermal initiator and a third portion of diluent; preferably, maintaining the reflux temperature for a set time again

[0074] In some embodiments of the present invention, the step of cooling and discharging includes: adding a diluent to adjust the solid content of the organosilicon-modified acrylate copolymer after cooling, and discharging after stirring.

[0075] In some embodiments of the present invention, the method for preparing the silicone pressure-sensitive adhesive includes:

[0076] Add diluent, MQ resin and dimethyl silicone rubber to the reaction device, and heat while stirring until the MQ resin and dimethyl silicone rubber are completely dissolved in the diluent to form a homogeneous solution; preferably, heat to 100° C. while stirring;

[0077] Add the alkaline catalyst while stirring and heat to reflux;

[0078] Continue the reaction at reflux temperature for a set time, and add an acidic neutralizing agent; preferably, continue the reaction at reflux temperature for 4-10 hours;

[0079] The mixture is cooled to room temperature, a thermal crosslinking agent is added, and the mixture is stirred and then discharged to obtain a silicone pressure-sensitive adhesive; preferably, in the step of stirring and then discharging, the mixture is stirred for 15 minutes and then discharged.

[0080] In some embodiments of the present invention, in the step of adding a thermal crosslinking agent, 1.0-5.0% of the thermal crosslinking agent is added to the total weight of the reaction solution, and the reaction solution is a solution after the acidic neutralizing agent is added and reacted.

[0081] The present invention not only combines the advantages of both silicone pressure-sensitive adhesive and acrylic pressure-sensitive adhesive, but also more effectively improves the stability of the blend, thereby facilitating large-scale industrial production.

[0082] Compared with the prior art, the beneficial technical effects of the present invention include:

[0083] First, the present invention uses an organosilicon-modified acrylate copolymer as a phase stability compatibilizer, thereby significantly improving the performance stability of the blend of organosilicon pressure-sensitive adhesive and acrylic pressure-sensitive adhesive;

[0084] Second, adding silicone-modified acrylate copolymers to the blend of silicone pressure-sensitive adhesive and polyacrylate pressure-sensitive adhesive can significantly improve the peel strength;

[0085] Third, adding silicone-modified acrylate copolymers to the blend of silicone pressure-sensitive adhesive and polyacrylate pressure-sensitive adhesive can not only significantly increase the peel strength, but also significantly improve the high-temperature resistance.

[0086] Fourth, compared with single polyacrylate pressure-sensitive adhesives or organosilicon pressure-sensitive adhesives, the organosilicon-modified polyacrylate pressure-sensitive adhesive of the present invention has better compatibility with Western or traditional Chinese medicines, can be repeatedly peeled and applied, is non-sticky, and has the characteristics of no adhesive overflow at high temperatures.

[0087] Fifth, the preparation method of each component of the silicone-modified polyacrylate pressure-sensitive adhesive of the present invention not only has greater flexibility and a simpler application process, but also has lower technical implementation costs, facilitating large-scale industrial production. DETAILED DESCRIPTION

[0088] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0089] The various reaction components used in the examples, including vinyl silicone oil, are commercially available.

[0090] Example 1

[0091] The preparation method of the organosilicon-modified acrylate copolymer of this embodiment includes:

[0092] (1) 20 kg of vinyl silicone oil (viscosity of approximately 5000 cps) and 10 kg of ethyl acetate were added to a reaction kettle and heated to 82°C while stirring;

[0093] (2) A mixture of 4 kg of acrylic acid, 70 kg of 2-ethylhexyl acrylate, 76 kg of ethyl acetate, 24 kg of methyl methacrylate, 2 kg of glycidyl methacrylate (GMA), and 0.3 kg of azoisobutyronitrile was added dropwise to the above-mentioned reaction kettle over 3 hours. After the addition was completed, the temperature was maintained at 82° C. and the reaction was continued for 3 hours.

[0094] (3) 0.1 kg of azoisobutyronitrile and 10 kg of ethyl acetate solution were added dropwise to the reactor over 60 minutes and maintained at 82°C for 4 hours;

[0095] (4) The temperature of the reactor was lowered to 40° C., ethyl acetate was added to adjust the solid content of the final product to 20%, and the product was discharged after stirring for 5 minutes to obtain a silicone-modified acrylate copolymer.

[0096] Example 2

[0097] The preparation method of the polyacrylate pressure-sensitive adhesive of this embodiment includes:

[0098] (1) 1.0 kg acrylic acid, 14 kg 2-ethylhexyl acrylate, 30 kg ethyl acetate, and 0.05 kg azoisobutyronitrile were added to a reactor, and the mixture was slowly heated to 82°C while stirring;

[0099] (2) A mixture of 4.5 kg of acrylic acid, 42 kg of 2-ethylhexyl acrylate, 8.6 kg of vinyl acetate, and 0.3 kg of azoisobutyronitrile was added dropwise to the above-mentioned reaction kettle over 3 hours. After the addition was complete, the temperature was maintained at 82° C. and the reaction was continued for 3 hours.

[0100] (3) The temperature of the reactor was lowered to 40° C., ethyl acetate was added to adjust the solid content of the final product to 40%, and the product was discharged after stirring for 5 minutes to obtain a polyacrylate pressure-sensitive adhesive.

[0101] Example 3

[0102] The preparation method of the organosilicon pressure-sensitive adhesive of this embodiment includes:

[0103] (1) 34 kg MQ resin, 26 kg dimethyl silicone rubber and 40 kg toluene were added to a reactor and heated to 100 °C while stirring until the MQ resin and dimethyl silicone rubber were completely dissolved in the toluene to form a homogeneous solution;

[0104] (2) Add sodium hydroxide as a catalyst while stirring, and heat the solution to reflux (112°C);

[0105] (3) The solution was allowed to react at reflux temperature for 6 hours, and then phosphoric acid was added to neutralize the sodium hydroxide in the solution;

[0106] (4) adding toluene to adjust the solid content of the final product to 40% and cooling to room temperature;

[0107] (5) Add 2.0% benzoyl peroxide based on the total weight of the solution, stir for 15 minutes and then discharge the material to obtain a silicone pressure-sensitive adhesive.

[0108] In Example 4, Example 5, and Comparative Example 1, the components listed in Table 1 below, namely, the silicone-modified acrylate copolymer of Example 1, the polyacrylate pressure-sensitive adhesive of Example 2, and the silicone pressure-sensitive adhesive of Example 3, were uniformly mixed. The mixture was then coated onto a 50-μm-thick PET film and baked at 170°C for 5 minutes to obtain 25-μm-thick tape test samples. The 180° peel strength was measured using a desktop tensile testing machine according to GB / T 2792-1998. The test results are shown in Table 1.

[0109] Table 1

[0110]

[0111] The test results shown in the table above demonstrate that, compared to Comparative Example 1, the addition of the organosilicon-modified acrylate copolymer to a blend of an organosilicon pressure-sensitive adhesive and an acrylic pressure-sensitive adhesive significantly improves peel strength in Examples 4 and 5. Compared to existing methods, the present invention offers a simpler process, more flexible formulations, and lower formulation material and production costs.

[0112] Example 6

[0113] The preparation method of the polyacrylate pressure-sensitive adhesive of this embodiment includes:

[0114] (1) Add 0.1 kg of acrylic acid, 4.4 kg of n-butyl acrylate, 0.4 kg of methyl methacrylate, 0.1 kg of glycidyl methacrylate (GMA), 7.5 kg of ethyl acetate, and 0.01 kg of azoisobutyronitrile into a reactor, and slowly heat the mixture in the reactor to 82°C while stirring;

[0115] A mixture of 0.1 kg acrylic acid, 5.4 kg n-butyl acrylate, 0.5 kg methyl methacrylate, 0.1 kg glycidyl methacrylate (GMA), 7.6 kg ethyl acetate and 0.02 kg azoisobutyronitrile was added dropwise to the above reactor over 3 hours. After the addition was complete, the temperature was maintained at 82° C. and the reaction was continued for 5 hours.

[0116] (3) The temperature of the reactor was lowered to 40° C., ethyl acetate was added to adjust the solid content of the final product to 40%, and the product was discharged after stirring for 5 minutes to obtain a polyacrylate pressure-sensitive adhesive.

[0117] Example 7

[0118] The preparation method of the organosilicon-modified acrylate copolymer of this embodiment includes:

[0119] (1) 20 kg of vinyl silicone oil (viscosity of about 5000 cps), 1 kg of acrylic acid, 10 kg of 2-ethylhexyl acrylate, 26 kg of ethyl acetate, 4 kg of methyl methacrylate, 1 kg of glycidyl methacrylate (GMA), and 0.05 kg of azoisobutyronitrile were added to a reactor and heated to 82°C while stirring.

[0120] (2) A mixture of 5 kg of vinyl silicone oil (viscosity of about 3000 cps), 4 kg of acrylic acid, 60 kg of 2-ethylhexyl acrylate, 60 kg of ethyl acetate, 20 kg of methyl methacrylate, 1 kg of glycidyl methacrylate (GMA), and 0.25 kg of benzoyl peroxide was added dropwise to the above-mentioned reactor over 3 hours. After the addition was complete, the temperature was maintained at 82° C. and the reaction was continued for 5 hours.

[0121] (3) 0.1 kg of azoisobutyronitrile and 10 kg of ethyl acetate solution were added dropwise to the reactor over 60 minutes and maintained at 82°C for 4 hours;

[0122] (4) The temperature of the reactor was lowered to 40° C., ethyl acetate was added to adjust the solid content of the final product to 20%, and the product was discharged after stirring for 5 minutes to obtain a silicone-modified acrylate copolymer (C).

[0123] In Example 8, Example 9, and Comparative Example 2, the components of the silicone pressure-sensitive adhesive of Example 3, the polyacrylate pressure-sensitive adhesive of Example 6, and the silicone-modified acrylate copolymer of Example 7, listed in Table 2 below, were uniformly mixed and coated onto 50-μm-thick PET films. The films were then baked at 170°C for 5 minutes to produce tape test samples with a thickness of 25 μm. The high-temperature resistance test was tested according to the following test method: the tape test sample was affixed to a steel plate and irradiated twice with a 2-kg pressure irradiator. The tape was then placed in an oven at 220°C and allowed to stand for 30 minutes. The steel plate was then removed from the oven and cooled for 30 minutes. The test tape was then uniformly removed from the steel plate and observed for any residual adhesive or shrinkage. The absence of residual adhesive or shrinkage was defined as passing the high-temperature resistance test. The test results are shown in Table 2.

[0124] Table 2

[0125]

[0126] From the test results shown in the above table, it can be seen that compared with Comparative Example 2, adding silicone-modified acrylate copolymer to the blend of silicone pressure-sensitive adhesive and acrylic pressure-sensitive adhesive in Examples 8-9 can not only significantly improve the peel strength, but also improve the high temperature resistance.

[0127] In Example 10, Example 11, and Comparative Example 3, the components listed in Table 3 below, including the silicone-modified acrylate copolymer of Example 1, the polyacrylate pressure-sensitive adhesive of Example 2, and the silicone pressure-sensitive adhesive of Example 3, were uniformly mixed and coated onto 50-μm-thick PET films. The films were baked at 170°C for 5 minutes to obtain 25-μm-thick tape test samples. The 180° peel strength was measured using a desktop tensile testing machine according to GB / T 2792-1998. The test results are shown in Table 3.

[0128] Table 3

[0129]

[0130] From the comparison of the data of Comparative Example 3 and Comparative Example 1 in the above table, it can be seen that the addition amount of the silicone-modified acrylate copolymer is too large, which actually reduces the peel strength.

[0131] In Example 12, Example 13, and Comparative Example 4, the components of the silicone pressure-sensitive adhesive of Example 3, the polyacrylate pressure-sensitive adhesive of Example 6, and the silicone-modified acrylate copolymer of Example 7, listed in Table 4 below, were uniformly mixed and coated onto 50-μm-thick PET films. The films were then baked at 170°C for 5 minutes to produce tape test samples with a thickness of 25 μm. The high-temperature resistance test was tested according to the following test method: the tape test sample was affixed to a steel plate and irradiated twice with a 2-kg pressure irradiator. The tape was then placed in an oven at 220°C and allowed to stand for 30 minutes. The steel plate was then removed from the oven and cooled for 30 minutes. The test tape was then uniformly removed from the steel plate and observed for any residual adhesive or shrinkage. The absence of residual adhesive or shrinkage was defined as passing the high-temperature resistance test. The test results are shown in Table 4.

[0132] Table 4

[0133]

[0134]

[0135] From the comparison of the data of Comparative Example 4 and Comparative Example 2 in the above table, it can be seen that the addition amount of the silicone-modified acrylate copolymer is too large, which actually reduces the peel strength and high temperature resistance.

[0136] In Example 14, the mass of vinyl silicone oil added in step (2) of the preparation method of the silicone-modified acrylate copolymer relative to that in Example 7 is 10 kg; in Example 15, the mass of vinyl silicone oil added in step (1) of the preparation method of the silicone-modified acrylate copolymer relative to that in Example 7 is 10 kg; in Comparative Example 5, the mass of vinyl silicone oil added in step (1) of the preparation method of the silicone-modified acrylate copolymer relative to that in Example 7 is 0.9 kg, and no vinyl silicone oil is added in step (2); in Comparative Example 6, the mass of vinyl silicone oil added in step (1) of the preparation method of the silicone-modified acrylate copolymer relative to that in Example 7 is 290 kg.

[0137] In Examples 16, 17, 18, and 19, the silicone pressure-sensitive adhesive of Example 3, the polyacrylate pressure-sensitive adhesive of Example 6, and the silicone-modified acrylate copolymers of Examples 14, 15, Comparative Examples 5, and 6, respectively, listed in Table 4, were uniformly mixed. The mixture was then coated onto a 50-μm-thick PET film and baked at 170°C for 5 minutes to produce 25-μm-thick tape test samples. The test results for the samples are shown in Table 5.

[0138] Table 5

[0139]

[0140]

[0141] From the comparison in the above table, it can be seen that adding too much or too little vinyl silicone oil to the silicone-modified acrylate copolymer reduces the peel strength and high temperature resistance of the silicone-modified polyacrylate pressure-sensitive adhesive.

[0142] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0143] The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein.

[0144] Second-order terms are used to indicate names, not to indicate any particular order.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A silicone-modified polyacrylate pressure-sensitive adhesive, characterized in that: Calculated by mass, it includes the following components: 29-39 parts of polyacrylate pressure-sensitive adhesive; 57-62 parts of silicone pressure-sensitive adhesive; and 2-9 parts of silicone modified acrylate copolymer; The sum of the mass percentages of the polyacrylate pressure-sensitive adhesive, the silicone pressure-sensitive adhesive and the silicone-modified acrylate copolymer is 100%; The organosilicon-modified acrylate copolymer comprises the following components calculated in parts by mass: 44-47 parts of alkyl (meth)acrylate and monomer with polar functional group; Thermal initiator 0.1~0.2 parts; 42-45 parts of diluent; and 8-12 parts of polymerized silicone oil The sum of the mass percentages of the components of the organosilicon-modified acrylate copolymer is 100%; in, The polymeric silicone oil is a vinyl (CH2=CH-) silicone oil, and both ends of its polydimethylsilane main chain have vinyl groups; The (meth)acrylate alkyl ester and the monomer with polar functional group at least include glycidyl methacrylate; The preparation method of the organosilicon-modified acrylate copolymer comprises: Adding a first batch of materials to a reaction device, stirring and heating, wherein the first batch of materials includes a first portion of diluent, a first portion of polymerized silicone oil, a first portion of alkyl (meth)acrylate and a monomer with a polar functional group and a first portion of thermal initiator; When the first batch of materials in the reaction device begins to reflux, the second batch of materials is added and the reflux temperature is maintained, wherein the second batch of materials includes a second portion of alkyl (meth)acrylate and a monomer with a polar functional group, a second portion of polymerized silicone oil, a second portion of thermal initiator, and a second portion of diluent; Adding the third batch of materials, maintaining the reflux temperature for the set time again, cooling and discharging the materials to obtain an organosilicon-modified acrylate copolymer, wherein the third batch of materials includes a third portion of thermal initiator and a third portion of diluent; Among them, the first part of the diluent accounts for 20~85% of the total diluent, and the second part of the diluent accounts for 50~80% of the total diluent; the first part of the (meth)acrylate alkyl ester and the monomer with a polar functional group accounts for 0~50% of the total amount of the (meth)acrylate alkyl ester and the monomer with a polar functional group; the first part of the thermal initiator accounts for 0~50% of the total amount of the thermal initiator, and the second part of the thermal initiator accounts for 50~80% of the total amount of the thermal initiator; the first part of the polymerized silicone oil accounts for 50~100% of the total amount of the vinyl silicone oil.

2. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 1, characterized in that: The number of carbon atoms of the alkyl group in the (meth)acrylate in the organosilicon-modified acrylate copolymer is 1 to 22.

3. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 1, characterized in that: The (meth)acrylic acid alkyl ester and the monomer with polar functional group also include acrylic acid and / or 2-ethylhexyl acrylate and / or methyl methacrylate.

4. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 1, characterized in that The thermal initiator is a peroxide initiator and / or an azo initiator.

5. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 1, characterized in that: The diluent is one or more organic solvents selected from aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons.

6. The organosilicon-modified polyacrylate pressure-sensitive adhesive according to claim 1, wherein The viscosity of the vinyl silicone oil is 200-20,000 cps.

7. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 1, characterized in that: The polyacrylate pressure-sensitive adhesive comprises the following components, calculated in parts by mass: 40-70 parts of alkyl (meth)acrylate and monomer with polar functional group; 0.01 to 1.0 parts of thermal initiator; and 29~59 parts of diluent.

8. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 7, characterized in that: In the polyacrylate pressure-sensitive adhesive: The sum of the mass percentages of the (meth)acrylate alkyl ester, the monomer with a polar functional group, the thermal initiator, and the diluent is 100%.

9. The organosilicon-modified polyacrylate pressure-sensitive adhesive according to claim 7, characterized in that: The polyacrylate pressure-sensitive adhesive comprises the following components, calculated in parts by mass: 42-62 parts of alkyl (meth)acrylate and monomer with polar functional group; 0.1 to 0.4 parts of thermal initiator; and 37.9~57.9 parts of diluent.

10. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 9, characterized in that: In the polyacrylate pressure-sensitive adhesive: The sum of the mass percentages of the (meth)acrylate alkyl ester, the monomer with a polar functional group, the thermal initiator, and the diluent is 100%.

11. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 7, characterized in that: The number of carbon atoms of the alkyl group in the (meth)acrylate monomer is 1 to 22.

12. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 7, characterized in that: The thermal initiator is a peroxide initiator and / or an azo initiator.

13. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 1, characterized in that: The organosilicon pressure-sensitive adhesive comprises the following components calculated by weight: 10-40 parts of dimethyl silicone rubber; MQ resin 15-40 parts; 0.01~1.0 parts of basic catalyst; Acid neutralizer 0.01~1.0 part; 30-70 parts of diluent; and Thermal crosslinking agent 0.5~2.0 parts.

14. The silicone-modified polyacrylate pressure-sensitive adhesive according to claim 13, characterized in that: In the silicone pressure-sensitive adhesive: The sum of the mass percentages of the dimethyl silicone rubber, the MQ resin, the alkaline catalyst, the acidic neutralizer, the diluent, and the thermal crosslinking agent is 100%.

15. The organosilicon-modified polyacrylate pressure-sensitive adhesive according to claim 14, wherein: The viscosity of the dimethyl silicone rubber at 25° C. is 20,000 cps to 30,000,000 cps.

16. The organosilicon-modified polyacrylate pressure-sensitive adhesive according to claim 14, characterized in that: The thermal crosslinking agent is a peroxide initiator.

17. The organosilicon-modified polyacrylate pressure-sensitive adhesive according to claim 14, characterized in that: The diluent is one or more organic solvents selected from aromatic hydrocarbons, aliphatic hydrocarbons or alicyclic hydrocarbons.

18. A method for preparing the organosilicon-modified polyacrylate pressure-sensitive adhesive according to any one of claims 1 to 17, characterized in that: include: Mixing polyacrylate pressure-sensitive adhesive, silicone pressure-sensitive adhesive and silicone-modified acrylate copolymer to obtain a mixed adhesive; The mixed adhesive is coated on a substrate and dried to obtain an organosilicon-modified polyacrylate pressure-sensitive adhesive.

19. The method for preparing the silicone-modified polyacrylate pressure-sensitive adhesive according to claim 18, characterized in that: The step of cooling and discharging comprises: adding a diluent after cooling to adjust the solid content of the organosilicon-modified acrylate copolymer, stirring and then discharging.

20. The method for preparing the silicone-modified polyacrylate pressure-sensitive adhesive according to claim 18, wherein: The preparation method of the polyacrylate pressure-sensitive adhesive comprises: Adding the first batch of materials to the reaction device, stirring and heating, wherein the first batch of materials includes the first portion of diluent, the first portion of alkyl (meth)acrylate and the monomer with polar functional group and the first portion of thermal initiator; When the first batch of materials in the reaction device begins to reflux, the second batch of materials is added and the reflux temperature is maintained, wherein the second batch of materials includes a second portion of alkyl (meth)acrylate and a monomer with a polar functional group, a second portion of a thermal initiator, and a second portion of a diluent; Cooling and discharging to obtain polyacrylate pressure-sensitive adhesive; Among them, the first part of the diluent accounts for 20~85% of the total diluent; the first part of the (meth)acrylate alkyl ester and the monomer with a polar functional group accounts for 0~60% of the total amount of the (meth)acrylate alkyl ester and the monomer with a polar functional group; the first part of the thermal initiator accounts for 0~50% of the total amount of the thermal initiator; the second part of the thermal initiator accounts for 50~80% of the total amount of the thermal initiator.

21. The method for preparing the silicone-modified polyacrylate pressure-sensitive adhesive according to claim 20, characterized in that: Before the step of cooling and discharging, the method further includes: adding a third batch of materials and maintaining the reflux temperature for a set time again. The third batch of materials includes a third portion of thermal initiator and a third portion of diluent.

22. The method for preparing the silicone-modified polyacrylate pressure-sensitive adhesive according to claim 18, wherein: The preparation method of the organosilicon pressure-sensitive adhesive comprises: Add diluent, MQ resin and dimethyl silicone rubber to the reaction device, and heat while stirring until the MQ resin and dimethyl silicone rubber are completely dissolved in the diluent to form a homogeneous solution; Add the alkaline catalyst while stirring and heat to reflux; Continue the reaction at reflux temperature for a set time and add an acidic neutralizing agent; The mixture was cooled to room temperature, a thermal cross-linking agent was added, and the mixture was stirred and then discharged to obtain a silicone pressure-sensitive adhesive.

23. The method for preparing the silicone-modified polyacrylate pressure-sensitive adhesive according to claim 22, characterized in that: In the step of adding a thermal crosslinking agent, 1.0-5.0% of the total weight of the reaction solution is added as the thermal crosslinking agent, and the reaction solution is the solution after the acidic neutralizing agent is added and reacted.

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