Double-sided adhesive tape for automobile rearview mirror heating sheet, acrylate pressure-sensitive adhesive and preparation method of acrylate pressure-sensitive adhesive

Abstract

The invention provides an acrylate pressure-sensitive adhesive for a double-sided tape for bonding an automobile rearview mirror heating sheet. The acrylate pressure-sensitive adhesive comprises the following components in parts by weight: 10-15 parts of a butyl acrylate monomer; 25 to 30 parts of an isooctyl acrylate monomer; 3.0 to 6.0 parts of a functional monomer; 2.5 to 5 parts of a hard monomer methyl methacrylate; 0.5 to 1.0 part of an initiator; and 43-59 parts of a solvent. The invention also provides a double-sided adhesive tape for bonding the heating sheet of the automobile rearview mirror, the double-sided adhesive tape is prepared from the acrylate pressure-sensitive adhesive and a polyester substrate PET, and the double-sided adhesive tape for the heating sheet of the automobile rearview mirror has the advantages of strong and stable viscosity, high temperature resistance, good adhesion with the heating sheet, small influence on the resistance of the heating sheet, and good adhesion with the heating sheet. The change rate of the resistance of the double-sided adhesive tape is within 8% under the normal temperature condition after the double-sided adhesive tape is bonded with the heating sheet, the change rate of the resistance of the heating sheet is within 25% after 1 hour under the high temperature condition, and the bonding requirement of the automobile rearview mirror heating sheet is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acrylate pressure-sensitive adhesive, in particular to a double-sided tape for automobile rearview mirror heating sheet, an acrylate pressure-sensitive adhesive for bonding automobile rearview mirror heating sheet double-sided tape and a preparation method thereof. BACKGROUND

[0002] In recent years, with the development of the automobile industry, the production and sales of automobiles have increased rapidly, and the popularity of automobiles has been increasing, driving the rapid development of the automobile manufacturing industry chain. The automobile rearview mirror is an important part of safe driving of the automobile, and the driver can master the road conditions in real time through observation of the rearview mirror, thereby improving the safety of driving. However, in rainy and foggy weather, alternating cold and hot climates, and winter, water droplets are easily condensed, frost is easily formed, and ice is easily formed on the surface of the automobile rearview mirror, which seriously affects the real-time mastery of the road conditions by the driver, thereby causing serious traffic safety hazards. In view of the above problems, the solution to the automobile rearview mirror is to increase the defrosting and demisting function, and this type of automobile rearview mirror mainly increases a heating sheet functional component, including a printed circuit heating sheet, a double-sided tape for bonding the heating sheet and the mirror surface. The resistance of the heating sheet printed circuit is constant, but the external conditions have a great influence on the change of the resistance. The double-sided tape for automobile rearview mirror heating sheet is used to bond and fix the heating sheet and the mirror surface of the rearview mirror, and directly contacts the heating sheet printed circuit. The conventional double-sided tape has a great influence on the resistance of the heating sheet printed circuit, so that the heating sheet works unstably, and even the heating function fails.

[0003] In order to solve the above problems, the present application provides a bonding scheme for the automobile rearview mirror heating sheet and the mirror surface with a simple preparation process, including an acrylate pressure-sensitive adhesive for automobile rearview mirror heating sheet double-sided tape and a preparation method of the double-sided tape. SUMMARY

[0004] The technical problem solved by the present application is to provide an acrylate pressure-sensitive adhesive for automobile rearview mirror heating sheet, a preparation method thereof and a double-sided tape for bonding automobile rearview mirror heating sheet.

[0005] To solve the above technical problems, the present application provides an acrylate pressure-sensitive adhesive for bonding automobile rearview mirror heating sheet double-sided tape, characterized in that it comprises the following components by weight:

[0006] 100 parts of acrylate polymer;

[0007] 0.4-1.2 parts of curing agent;

[0008] 5-15 parts of first solvent;

[0009] The acrylate polymer comprises the following components by mass:

[0010] 10-15 parts of butyl acrylate monomer;

[0011] Isobutyl acrylate monomer, 25-30 parts;

[0012] Functional monomer, 3.0-6.0 parts;

[0013] Methyl methacrylate hard monomer, 2.5-5.0 parts;

[0014] Initiator, 0.5-1.0 parts;

[0015] Second solvent, 43-59 parts.

[0016] Preferably, the functional monomer comprises a combination of one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate (GMA).

[0017] Preferably, the initiator is a combination of one or more of azobisisobutyronitrile, dibenzoyl peroxide, lauryl peroxide.

[0018] Preferably, the first solvent and the second solvent are each independently selected from a combination of one or more of ethyl acetate, toluene, butanone, isopropyl alcohol.

[0019] Preferably, the curing agent is selected from one of an isocyanate curing agent which is hexamethylene diisocyanate biuret, or an epoxy curing agent which is a tetrafunctional epoxy curing agent.

[0020] Preferably, the acrylic ester polymer has a solid content of 40-57 %, a viscosity of 4000-7000 CPS, and a weight average molecular weight Mw of 0.5-1 million.

[0021] The second aspect of the present application provides a preparation method of the acrylic ester pressure-sensitive adhesive for bonding the heating sheet of the automobile rearview mirror, characterized in that the method comprises the following steps:

[0022] (1) A certain amount of the second solvent, butyl acrylate monomer, isobutyl acrylate, functional monomer, and methyl methacrylate hard monomer are added to a reaction kettle equipped with a thermometer, condenser, and emulsifying tank, and stirred to mix uniformly; nitrogen is introduced into the reaction kettle, and part of the initiator is dissolved in an appropriate amount of the second solvent and added to the reaction kettle, and stirring and heating are started, and the temperature is raised to 80-83 ℃ and reacted for 1-3 h;

[0023] (2) Start by adding a mixed solution of butyl acrylate monomer, isooctyl acrylate, functional monomer, and methyl methacrylate hard monomer in a certain ratio, and dissolve part of the initiator in an appropriate amount of second solvent. Add the solution dropwise into the reaction vessel and finish the addition within 1-3 hours. Keep the reaction at 80-83 °C for 2-4 hours. Then add the remaining initiator dissolved in an appropriate amount of second solvent, finish the addition within 5-15 minutes, and continue to keep the reaction at 80-83 °C for 4-8 hours.

[0024] (3) Add the remaining second solvent to dilute to a solid content of 40-57% to obtain a pale yellow, transparent, viscous acrylate polymer;

[0025] (4) Stir the acrylate polymer, curing agent and first solvent prepared in step (3) evenly according to the proportion to obtain the finished pressure-sensitive adhesive.

[0026] The third aspect of the present invention provides a double-sided adhesive tape for automotive rearview mirror heating elements, comprising, in sequence, a pressure-sensitive adhesive layer, a substrate layer, and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive coating as described in the first aspect of the present invention, and / or is prepared according to the preparation method described in the second aspect of the present invention.

[0027] This invention also provides a method for preparing double-sided adhesive tape for automotive rearview mirror heating elements, comprising the following steps:

[0028] The pressure-sensitive adhesive prepared by the preparation method provided by the present invention is coated onto a PET substrate layer, and after curing and drying, a pressure-sensitive adhesive layer is obtained. Then, release paper is laminated to obtain a single-sided double-sided tape.

[0029] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then rolled up to obtain double-sided tape for bonding automotive rearview mirror heating elements.

[0030] Furthermore, the thickness of the pressure-sensitive adhesive monolayer is 25-40 μm, preferably 30-35 μm.

[0031] Furthermore, the thickness of the substrate layer is 20-40 μm, preferably 25-36 μm.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The acrylate pressure-sensitive adhesive for automotive rearview mirror heating elements prepared by the present invention uses soft monomers butyl acrylate, isooctyl acrylate, functional monomers, and hard monomers methyl methacrylate. Through formulation and process design, it has excellent anti-resistance properties, strong peel strength, high temperature resistance and aging resistance, and has little impact on the resistance of automotive rearview mirror heating elements. It meets the operating conditions of heating elements. The resistance change rate of heating elements is within 8% at room temperature and within 25% at high temperature.

[0034] (2) The double-sided tape for heating elements of car rearview mirrors provided by the present invention uses polyester substrate (PET) as the base material. The double-sided tape is used to fix the heating element and the mirror surface of the rearview mirror. It has excellent and reliable bonding performance, high temperature resistance, and is suitable for the actual application scenarios of heating elements of car rearview mirrors.

[0035] (3) This invention obtains an acrylic pressure-sensitive adhesive with excellent anti-resistance properties through a special formula and process design. It uses carboxyl-free acrylic functional monomers, which do not affect the resistance of the rearview mirror heating element. An external curing agent is used for post-crosslinking, forming a molecular structure with a suitable crosslinking density, thus enhancing the temperature resistance of the acrylic pressure-sensitive adhesive. The ultimate beneficial effect of the product is that the double-sided adhesive tape for automotive rearview mirror heating elements has minimal impact on the resistance change of the heating element under high temperature and high humidity conditions, exhibiting stable reliability and excellent adhesion performance, meeting the bonding application requirements of automotive rearview mirror heating elements. Attached Figure Description

[0036] Figure 1 The illustration shows a scenario where the resistance value of the resistor itself is tested.

[0037] Figure 2 The illustration shows a scenario where resistance is tested after tape is applied to a resistor sheet. Detailed Implementation

[0038] Example 1

[0039] I. Preparation of acrylate polymers

[0040] Raw material composition:

[0041] Butyl acrylate monomer: 10 parts;

[0042] Isooctyl acrylate monomer: 25 parts;

[0043] Acrylic functional monomer: hydroxyethyl acrylate, 3.0 parts;

[0044] Methyl methacrylate hard monomer: 2.5 parts;

[0045] Initiator: benzoyl peroxide, 0.4 parts; azobisisobutyronitrile, 0.1 parts;

[0046] Second solvent: ethyl acetate, 59 parts.

[0047] Preparation method:

[0048] (1) Add 35 parts of ethyl acetate, 6 parts of butyl acrylate monomer, 15 parts of isooctyl acrylate, 1.8 parts of hydroxyethyl acrylate, and 1.5 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.2 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 °C and react for 1.5 h;

[0049] (2) Start by adding a monomer initiator solution consisting of 4 parts butyl acrylate monomer, 10 parts isooctyl acrylate, 1.2 parts hydroxyethyl acrylate, 1.0 parts methyl methacrylate hard monomer, and 0.2 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and complete the addition within 1.5 h. Keep the reactor at 82 ℃ for 3 h. Then add 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate and complete the addition within 10 minutes. Continue to keep the reactor at 82 ℃ for 6 h.

[0050] (3) Add 18 parts of ethyl acetate to dilute to a solid content of 40.5±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 4000-5000 cps and a molecular weight of 500,000-600,000.

[0051] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0052] Raw material composition:

[0053] 100 parts of the acrylate polymer prepared in step one;

[0054] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.4 parts;

[0055] First solvent: ethyl acetate, 5 parts;

[0056] Substrate: PET substrate

[0057] Preparation method:

[0058] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0059] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0060] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0061] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0062] Example 2

[0063] I. Preparation of acrylate polymers

[0064] Raw material composition:

[0065] Butyl acrylate monomer: 15 parts;

[0066] Isooctyl acrylate monomer: 30 parts;

[0067] Acrylic functional monomer: hydroxyethyl acrylate, 6.0 parts;

[0068] Methyl methacrylate hard monomer: 5.0 parts;

[0069] Initiator: benzoyl peroxide, 0.8 parts; azobisisobutyronitrile, 0.2 parts;

[0070] Second solvent: ethyl acetate, 43 parts.

[0071] Preparation method:

[0072] (1) Add 30 parts of ethyl acetate, 9 parts of butyl acrylate monomer, 18 parts of isooctyl acrylate, 3.6 parts of hydroxyethyl acrylate, and 3 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.4 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 °C and react for 1.5 h;

[0073] (2) Start by adding a monomer initiator solution consisting of 6 parts butyl acrylate monomer, 12 parts isooctyl acrylate, 2.4 parts hydroxyethyl acrylate, 2.0 parts methyl methacrylate hard monomer, and 0.4 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and complete the addition within 1.5 h. Keep the reactor at 82 ℃ for 3 h. Then add 0.2 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate. Add the solution dropwise within 10 minutes and continue to keep the reactor at 82 ℃ for 4 h.

[0074] (3) Add 7 parts of ethyl acetate to dilute to a solid content of 56.5±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 6000-7000 cps and a molecular weight of 800,000-1,000,000.

[0075] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0076] Raw material composition:

[0077] 100 parts of the acrylate polymer prepared in step one;

[0078] Curing agent: Isocyanate curing agent (model: L-45, manufacturer: Covestro Polymers (China) Co., Ltd.), 1.2 parts;

[0079] First solvent: ethyl acetate, 15 parts;

[0080] Substrate: PET substrate

[0081] Preparation method:

[0082] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0083] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0084] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0085] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0086] Example 3

[0087] I. Preparation of acrylate polymers

[0088] Raw material composition:

[0089] Butyl acrylate monomer: 12.5 parts;

[0090] Isooctyl acrylate monomer: 27.5 parts;

[0091] Acrylic functional monomer: hydroxyethyl acrylate, 4.5 parts;

[0092] Methyl methacrylate hard monomer: 4.5 parts;

[0093] Initiator: benzoyl peroxide, 0.6 parts; azobisisobutyronitrile, 0.1 parts;

[0094] Second solvent: ethyl acetate, 50.3 parts.

[0095] Preparation method:

[0096] (1) Add 30 parts of ethyl acetate, 7.5 parts of butyl acrylate monomer, 16.5 parts of isooctyl acrylate, 2.7 parts of hydroxyethyl acrylate, and 2.7 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.3 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 ℃ and react for 1.5 h;

[0097] (2) Start by adding a monomer initiator solution consisting of 5 parts butyl acrylate monomer, 11 parts isooctyl acrylate, 1.8 parts hydroxyethyl acrylate, 1.8 parts methyl methacrylate hard monomer, and 0.3 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and complete the addition within 1.5 h. Keep the reaction at 82 ℃ for 3 h. Then add 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate. Add the solution dropwise within 10 minutes and continue the reaction at 82 ℃ for 5 h.

[0098] (3) Add 14.3 parts of ethyl acetate to dilute to a solid content of 49.2±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 5500-6000 cps and a molecular weight of 700,000-800,000.

[0099] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0100] Raw material composition:

[0101] 100 parts of the acrylate polymer prepared in step one;

[0102] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.7 parts;

[0103] First solvent: ethyl acetate, 10 parts;

[0104] Substrate: PET substrate

[0105] Preparation method:

[0106] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0107] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0108] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0109] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0110] Example 4a

[0111] I. Preparation of acrylate polymers

[0112] Raw material composition:

[0113] Butyl acrylate monomer: 12 parts;

[0114] Isooctyl acrylate monomer: 26 parts;

[0115] Acrylic functional monomer: hydroxyethyl acrylate, 4.0 parts;

[0116] Methyl methacrylate hard monomer: 4.0 parts;

[0117] Initiator: benzoyl peroxide, 0.5 parts; azobisisobutyronitrile, 0.1 parts;

[0118] Second solvent: ethyl acetate, 53.4 parts.

[0119] Preparation method:

[0120] (1) Add 35 parts of ethyl acetate, 7.2 parts of butyl acrylate monomer, 15.6 parts of isooctyl acrylate, 2.4 parts of hydroxyethyl acrylate, and 2.4 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.25 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 ℃ and react for 1.5 h;

[0121] (2) Start by adding a monomer initiator solution consisting of 4.8 parts butyl acrylate monomer, 10.4 parts isooctyl acrylate, 1.6 parts hydroxyethyl acrylate, 1.6 parts methyl methacrylate hard monomer, and 0.25 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and complete the addition within 1.5 h. Keep the reactor at 82 ℃ for 3 h. Then add 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate. Add the solution dropwise within 10 minutes and continue to keep the reactor at 82 ℃ for 4 h.

[0122] (3) Add 12.4 parts of ethyl acetate to dilute to a solid content of 46.1±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 5500-6000 cps and a molecular weight of 700,000-800,000.

[0123] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0124] Raw material composition:

[0125] 100 parts of the acrylate polymer prepared in step one;

[0126] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.6 parts;

[0127] First solvent: ethyl acetate, 10 parts;

[0128] Substrate: PET substrate

[0129] Preparation method:

[0130] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0131] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0132] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0133] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0134] Example 4b

[0135] I. Preparation of acrylate polymers

[0136] Raw material composition:

[0137] Butyl acrylate monomer: 12 parts;

[0138] Isooctyl acrylate monomer: 26 parts;

[0139] Acrylic functional monomers: hydroxyethyl acrylate, 2.0 parts; hydroxypropyl acrylate, 2.0 parts;

[0140] Methyl methacrylate hard monomer: 4.0 parts;

[0141] Initiator: benzoyl peroxide, 0.5 parts; azobisisobutyronitrile, 0.1 parts;

[0142] Second solvent: ethyl acetate, 53.4 parts.

[0143] Preparation method:

[0144] (1) Add 35 parts of ethyl acetate, 7.2 parts of butyl acrylate monomer, 15.6 parts of isooctyl acrylate, 1.2 parts of hydroxyethyl acrylate, 1.2 parts of hydroxypropyl acrylate, and 2.4 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.25 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 ℃ and react for 1.5 h;

[0145] (2) Start by adding a monomer initiator solution consisting of 4.8 parts butyl acrylate monomer, 10.4 parts isooctyl acrylate, 0.8 parts hydroxyethyl acrylate, 0.8 parts hydroxypropyl acrylate, and 1.6 parts methyl methacrylate hard monomer, and 0.25 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and finish the addition within 1.5 h. Keep the reactor at 82 ℃ for 3 h. Then add 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate, finish the addition within 10 minutes, and continue the reaction at 82 ℃ for 4 h.

[0146] (3) Add 12.4 parts of ethyl acetate to dilute to a solid content of 46.1±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 5500-6000 cps and a molecular weight of 700,000-800,000.

[0147] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0148] Raw material composition:

[0149] 100 parts of the acrylate polymer prepared in step one;

[0150] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.6 parts;

[0151] First solvent: ethyl acetate, 10 parts;

[0152] Substrate: PET substrate

[0153] Preparation method:

[0154] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0155] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0156] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0157] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0158] Example 5a

[0159] I. Preparation of acrylate polymers

[0160] Raw material composition:

[0161] Butyl acrylate monomer: 12 parts;

[0162] Isooctyl acrylate monomer: 26 parts;

[0163] Acrylic functional monomers: hydroxyethyl acrylate, 3.0 parts; glycidyl methacrylate, 1.0 part;

[0164] Methyl methacrylate hard monomer: 4.0 parts;

[0165] Initiator: benzoyl peroxide, 0.5 parts; azobisisobutyronitrile, 0.1 parts;

[0166] Second solvent: ethyl acetate, 53.4 parts.

[0167] Preparation method:

[0168] (1) Add 35 parts of ethyl acetate, 7.2 parts of butyl acrylate monomer, 15.6 parts of isooctyl acrylate, 1.8 parts of hydroxyethyl acrylate, 0.6 parts of glycidyl methacrylate, and 2.4 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.25 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 °C and react for 1.5 h;

[0169] (2) Start by adding a monomer initiator solution consisting of 4.8 parts butyl acrylate monomer, 10.4 parts isooctyl acrylate, 1.2 parts hydroxyethyl acrylate, 0.4 parts glycidyl methacrylate, and 1.6 parts methyl methacrylate hard monomer, and 0.25 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and finish the addition within 1.5 h. Keep the reactor at 82 °C for 3 h. Then add 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate, finish the addition within 10 minutes, and continue the reaction at 82 °C for 4 h.

[0170] (3) Add 12.4 parts of ethyl acetate to dilute to a solid content of 46.1±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 6000-6500 cps and a molecular weight of 700,000-800,000.

[0171] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0172] Raw material composition:

[0173] 100 parts of the acrylate polymer prepared in step one;

[0174] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.6 parts;

[0175] First solvent: ethyl acetate, 10 parts;

[0176] Substrate: PET substrate

[0177] Preparation method:

[0178] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0179] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0180] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0181] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0182] Example 5b

[0183] I. Preparation of acrylate polymers

[0184] Raw material composition:

[0185] Butyl acrylate monomer: 12 parts;

[0186] Isooctyl acrylate monomer: 26 parts;

[0187] Acrylic functional monomers: hydroxyethyl acrylate, 2.0 parts; glycidyl methacrylate, 2.0 parts;

[0188] Methyl methacrylate hard monomer: 4.0 parts;

[0189] Initiator: benzoyl peroxide, 0.5 parts; azobisisobutyronitrile, 0.1 parts;

[0190] Second solvent: ethyl acetate, 53.4 parts.

[0191] Preparation method:

[0192] (1) Add 35 parts of ethyl acetate, 7.2 parts of butyl acrylate monomer, 15.6 parts of isooctyl acrylate, 1.2 parts of hydroxyethyl acrylate, 1.2 parts of glycidyl methacrylate, and 2.4 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.25 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 ℃ and react for 1.5 h;

[0193] (2) Start by adding a monomer initiator solution consisting of 4.8 parts butyl acrylate monomer, 10.4 parts isooctyl acrylate, 0.8 parts hydroxyethyl acrylate, 0.8 parts glycidyl methacrylate, and 1.6 parts methyl methacrylate hard monomer, and 0.25 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and finish the addition within 1.5 h. Keep the reactor at 82 °C for 3 h. Then add 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate. Add the solution dropwise within 10 minutes and continue the reaction at 82 °C for 4 h.

[0194] (3) Add 12.4 parts of ethyl acetate to dilute to a solid content of 46.1±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 6500-7000 cps and a molecular weight of 800,000-900,000.

[0195] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0196] Raw material composition:

[0197] 100 parts of the acrylate polymer prepared in step one;

[0198] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.6 parts;

[0199] First solvent: ethyl acetate, 10 parts;

[0200] Substrate: PET substrate

[0201] Preparation method:

[0202] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0203] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0204] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0205] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0206] Example 6

[0207] I. Preparation of acrylate polymers

[0208] Raw material composition:

[0209] Butyl acrylate monomer: 12 parts;

[0210] Isooctyl acrylate monomer: 26 parts;

[0211] Acrylic functional monomers: hydroxyethyl acrylate, 2.0 parts; hydroxypropyl acrylate, 1.5 parts; glycidyl methacrylate, 0.6 parts;

[0212] Methyl methacrylate hard monomer: 4.0 parts;

[0213] Initiator: benzoyl peroxide, 0.5 parts; azobisisobutyronitrile, 0.1 parts;

[0214] Second solvent: ethyl acetate, 53.3 parts.

[0215] Preparation method:

[0216] (1) Add 35 parts of ethyl acetate, 7.2 parts of butyl acrylate monomer, 15.6 parts of isooctyl acrylate, 1.2 parts of hydroxyethyl acrylate, 0.9 parts of hydroxypropyl acrylate, 0.3 parts of glycidyl methacrylate, and 2.4 parts of methyl methacrylate hard monomer to a reactor equipped with a thermometer, condenser, and emulsification tank, and start stirring to mix evenly; introduce nitrogen into the reactor, dissolve 0.25 parts of benzoyl peroxide in 2 parts of ethyl acetate and add it to the reactor, start stirring and heating, heat to 80 ℃ and react for 1.5 h;

[0217] (2) Start by adding dropwise a monomer initiator solution consisting of 4.8 parts butyl acrylate monomer, 10.4 parts isooctyl acrylate, 0.8 parts hydroxyethyl acrylate, 0.6 parts hydroxypropyl acrylate, 0.3 parts glycidyl methacrylate, and 1.6 parts methyl methacrylate hard monomer, and 0.25 parts benzoyl peroxide dissolved in 2 parts ethyl acetate. Add the solution dropwise into the reactor and complete the addition within 1.5 h. Keep the reactor at 82 ℃ for 3 h. Then add dropwise 0.1 parts azobisisobutyronitrile dissolved in 2 parts ethyl acetate within 10 minutes. Continue to keep the reactor at 82 ℃ for 4 h.

[0218] (3) Add 12.3 parts of ethyl acetate to dilute to a solid content of 46.1±0.5% to obtain a light yellow transparent viscous acrylate polymer with a viscosity of 6000-6500 cps and a molecular weight of 700,000-800,000.

[0219] II. Preparation of Double-Sided Adhesive Tape for Car Rearview Mirror Heating Elements

[0220] Raw material composition:

[0221] 100 parts of the acrylate polymer prepared in step one;

[0222] Curing agent: Tetrafunctional epoxidized m-phenylenediamine curing agent (model: GA-240, manufacturer: Shenzhen Jiadida Chemical Co., Ltd.), 0.6 parts;

[0223] First solvent: ethyl acetate, 10 parts;

[0224] Substrate: PET substrate

[0225] Preparation method:

[0226] Preparation of pressure-sensitive adhesive: When preparing the adhesive, mix and stir the acrylate polymer, GA-240 and ethyl acetate prepared in step one according to the mass ratio to obtain the coating adhesive formulation;

[0227] Preparation of double-sided tape for heating element of car rearview mirror: The pressure-sensitive adhesive prepared in step (1) is coated on PET substrate layer, cured and dried to obtain pressure-sensitive adhesive layer, and then composited with release paper to obtain single side of double-sided tape;

[0228] The pressure-sensitive adhesive is then coated onto the other side of the PET substrate layer. After curing and drying, a pressure-sensitive adhesive layer is obtained. The layer is then wound up to obtain double-sided adhesive tape for automotive rearview mirror heating elements. The drying temperature is 110 ℃ and the drying time is 2 min.

[0229] The product structure is as follows: 35μm pressure-sensitive adhesive layer, 25μm substrate layer, 35μm pressure-sensitive adhesive layer, and a total thickness of 95μm.

[0230] Comparative Example 1

[0231] This comparative example is used to illustrate the effect of the combined application of carboxyl-containing acrylic functional monomers on product performance. This comparative example is based on Example 1. Except that the acrylic functional monomer is an acrylic monomer, the other components and their preparation methods are the same as in Example 1.

[0232] Comparative Example 2

[0233] This comparative example is used to illustrate the effect of the combined application of carboxyl-containing acrylic functional monomers on product performance. This comparative example is based on Example 2. Except that the acrylic functional monomer is an acrylic monomer, the other components and their preparation methods are the same as in Example 2.

[0234] Performance testing

[0235] The automotive rearview mirror heating elements prepared in Examples 1-6 and Comparative Examples 1 and 2 were subjected to performance testing using double-sided adhesive tape. The specific testing methods are as follows, and the results are shown in Table 1.

[0236] (1) 180° peel force: According to GB / T 2792—2014 "Test method for peel strength of adhesive tape", the peel force tensile tester was used to measure the peel force (the tape width is 25 mm, and a 25 μm PET substrate is used for backing reinforcement, and the peel rate is 300 mm / min).

[0237] (2) Initial tack: The initial tack of pressure-sensitive adhesive tape was tested using an initial tack tester (tilt angle of 30°) in accordance with GB / T 4852—2002 "Test method for initial tack of pressure-sensitive adhesive tape (rolling ball method)".

[0238] (3) Holding power: The holding power of the pressure-sensitive adhesive is determined according to GB / T 4851—2014 standard. The adhesive sample with the pressure-sensitive adhesive tape is vertically suspended on the test frame, and a weight of a specified mass is hung below. The amount of displacement of the adhesive sample sliding down over a certain period of time (or the time it takes for the adhesive sample to completely detach) is used to characterize the holding power of the pressure-sensitive adhesive.

[0239] (4) Resistance performance test (room temperature / high temperature):

[0240] Equipment: DC low resistance tester, power supply.

[0241] Materials: Double-sided adhesive tape sample for preparing rearview mirror heating element, rearview mirror heating element.

[0242] Test steps:

[0243] 1. Testing the resistance value of the resistor element itself.

[0244] Turn on the DC low resistance tester by pressing the "POWER" button. The instrument will then work normally and the resistance display will show "00000". Take a resistance piece and fix the two clips of the DC low resistance tester to the two ends of the electroplated silver without ink on the resistance piece. Read the resistance value displayed at this time.

[0245] 2. Resistance test of tape-bonded resistor sheet

[0246] Apply tape to the ink-covered side of the resistor sheet, press it with a small roller to remove air bubbles, exposing the silver-plated ends without tape. This is for clamp testing of resistance values. The properly tapered resistor sheet is used for resistance testing at room temperature / with applied voltage / with applied heat. When applying tape to the resistor sheet, air bubbles must be avoided, as they will affect the resistance change.

[0247] 3. Room temperature resistance test

[0248] Test records were kept for the following durations: 2 hours after tape was applied to the resistor sheet, 1 day after 1 day, 2 days after 2 days, 3 days after 3 days, 7 days after 7 days, and 15 days after 15 days. The rate of change in resistance value was calculated.

[0249] Rate of change of resistance = (R2 - R1) / R1 × 100%

[0250] Where R1 is the initial resistance value after the resistor sheet is attached with double-sided tape, and R2 is the test resistance value after the resistor sheet is attached with double-sided tape under various experimental conditions.

[0251] 4. High-temperature resistance test

[0252] After the resistive sheet is attached with tape, the test sample is laid flat in a 115℃ oven (without overlapping). After 1 hour, the work is stopped, the oven door is opened, and after cooling, the test sample is taken out and placed at room temperature. The resistance value is measured and recorded after 24 hours, and the rate of change of the resistance value is calculated.

[0253] (5) Residual adhesive performance test

[0254] Double-sided adhesive tape was applied to the heated rearview mirror of the car onto a clean, special stainless steel test plate. The tape was pressed firmly onto each bonding area and placed in a constant temperature and humidity test chamber set at 85°C and 85% humidity. After 24 hours, the sample was removed, allowed to cool completely, and then peeled off to observe whether there was any adhesive residue on the steel plate.

[0255] Table 1 - Performance Test Results of Double-Sided Adhesive Tape for Automotive Rearview Mirror Heating Elements

[0256]

[0257] The comparative examples show that each component in the embodiments has a specific function, thereby achieving the application effect of the product. Compared with embodiments using functional monomers containing carboxyl groups, the examples using non-carboxyl functional monomers show that the carboxyl-containing functional monomers have a significant impact on the resistance change of the rearview mirror heating element and cannot be used in the preparation of anti-resistance automotive rearview mirror heating element double-sided adhesive tape. However, pressure-sensitive adhesives prepared without carboxyl-containing acrylate monomers generally have lower adhesion and cohesion, failing to meet the requirements of product application. Therefore, this invention uses a special formula and process to solve the above problems, while adding a certain proportion of other multifunctional acrylate functional monomers to improve the influence of the double-sided adhesive tape on the resistance change rate of the heating element. The invention addresses the issue of residual adhesiveness by introducing multifunctional acrylate monomers to enhance the crosslinking properties of the molecular chains, thereby improving the high-temperature resistance of the pressure-sensitive adhesive. Simultaneously, the use of an external curing agent for post-crosslinking forms a molecular structure with a suitable crosslinking density, further enhancing the temperature resistance of the acrylate pressure-sensitive adhesive. The functional monomers hydroxyethyl acrylate, hydroxypropyl acrylate, and glycidyl methacrylate provide different functional group crosslinking points for the pressure-sensitive adhesive molecular chains. The absence of carboxyl functional groups minimizes the impact on the resistance change of the rearview mirror heating element and allows for post-crosslinking reactions with the curing agent to improve cohesion, thus improving residual adhesiveness and high-temperature resistance. This invention utilizes different carboxyl-free functional monomers, and the addition ratio must be within a suitable range. A single functional monomer or an unsuitable ratio cannot achieve the ideal resistance change and high-temperature resistance application effects. The ultimate beneficial effect of the product is that the double-sided adhesive tape exhibits stable adhesion performance under high-temperature conditions and possesses excellent resistance change resistance.

[0258] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure made using the contents of the present invention specification and drawings, or directly or indirectly applied to other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An acrylate pressure-sensitive adhesive for bonding double-coated tapes for automotive rearview mirror heating sheets, characterized by, The components include the following weight parts: acrylate polymer, 100 parts; curing agent, 0.4-1.2 parts; first solvent, 5-15 parts; The acrylate polymer includes the following mass parts of components: butyl acrylate monomer, 10-15 parts; isooctyl acrylate monomer, 25-30 parts; functional monomer, 3.0-6.0 parts; methyl methacrylate hard monomer, 2.5-5.0 parts; initiator, 0.5-1.0 parts; second solvent, 43-59 parts.

2. The acrylate pressure-sensitive adhesive for bonding double-coated tapes for automotive rearview mirror heating sheets according to claim 1, characterized in that, The functional monomer includes a combination of one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, and glycidyl methacrylate GMA.

3. The acrylate pressure-sensitive adhesive for bonding double-coated tapes for automotive rearview mirror heating sheets according to claim 1, characterized in that, The initiator is a combination of one or more of azobisisobutyronitrile, dibenzoyl peroxide, and lauryl peroxide.

4. The acrylate pressure-sensitive adhesive for bonding double-coated tapes for automotive rearview mirror heating sheets according to claim 1, characterized in that, The first solvent and the second solvent are each independently selected from a combination of one or more of ethyl acetate, toluene, butanone, and isopropyl alcohol.

5. The acrylate pressure-sensitive adhesive for bonding double-coated tapes for automotive rearview mirror heating sheets according to claim 1, characterized in that, The curing agent is selected from one of an isocyanate curing agent, which is hexamethylene diisocyanate biuret, or an epoxy curing agent, which is a tetrafunctional epoxy curing agent.

6. The acrylate pressure-sensitive adhesive for bonding double-coated tapes for automotive rearview mirror heating sheets according to claim 1, characterized in that, The acrylate polymer has a solid content of 40-57%, a viscosity of 4000-7000 CPS, and a weight average molecular weight Mw of 0.5-1 million.

7. The method for preparing an acrylate pressure-sensitive adhesive for double- sided tape of automobile rearview mirror heating sheet according to any one of claims 1 to 6, characterized in that, The method includes the following steps: (1) A certain amount of the second solvent, butyl acrylate monomer, isooctyl acrylate, functional monomer, and methyl methacrylate hard monomer are added to a reaction kettle equipped with a thermometer, condenser, and emulsifying tank, and stirred to mix uniformly. Nitrogen is introduced into the reaction kettle, and a portion of the initiator is dissolved in an appropriate amount of the second solvent and added to the reaction kettle. Stirring is started, and heating is performed to 80-83°C and continued for 1-3 h. (2) A mixed solution of a certain amount of butyl acrylate monomer, isooctyl acrylate, functional monomer, and methyl methacrylate hard monomer, in which a portion of the initiator is dissolved in an appropriate amount of the second solvent, is added dropwise into the reaction kettle and dropped completely within 1-3 h. The temperature is maintained at 80-83°C, and the reaction is continued for 2-4 h. The remaining initiator dissolved in an appropriate amount of the second solvent is added dropwise within 5-15 min, and the temperature is maintained for 4-8 h. (3) The remaining second solvent is added to dilute the solution to a solid content of 40-57%, and a light yellow transparent viscous acrylate polymer is obtained. (4) The acrylate polymer obtained in step (3), the curing agent, and the first solvent are stirred uniformly according to the proportions, and a coating finished product pressure-sensitive adhesive is obtained.

8. A double-coated tape for bonding an automobile rearview mirror heating sheet, characterized by, The adhesive tape sequentially includes a pressure-sensitive adhesive layer, a substrate layer, and a pressure-sensitive adhesive layer. The substrate layer is a polyester film PET, and the pressure-sensitive adhesive layer is composed of the acrylate pressure-sensitive adhesive for bonding an automobile rearview mirror heating sheet double-sided adhesive tape according to any one of claims 1-6, and / or prepared by the preparation method of the acrylate pressure-sensitive adhesive for bonding an automobile rearview mirror heating sheet double-sided adhesive tape according to claim 7.

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