Boiling-resistant and heat-tackifying explosion-proof membrane for rear cover of mobile phone battery and preparation method thereof

Abstract

The invention discloses a boiling-resistant and heat-tackifying explosion-proof membrane for a rear cover of a mobile phone battery and a preparation method of the boiling-resistant and heat-tackifying explosion-proof membrane. The explosion-proof membrane comprises a base material layer, an acrylate pressure-sensitive adhesive layer and a release layer which are sequentially stacked, the preparation raw materials of the acrylate pressure-sensitive adhesive layer comprise a pressure-sensitive adhesive solution and tackifying resin, and the pressure-sensitive adhesive solution comprises the following raw material components in parts by weight: 30-45 parts of an acrylate soft monomer, 50-65 parts of an acrylate hard monomer, 2-10 parts of an acrylate functional monomer and 0.2-2 parts of an initiator. The explosion-proof membrane for the rear cover of the mobile phone battery, which is provided by the invention, has the advantages of high hardness, high elasticity, high temperature resistance, high humidity resistance and high steaming and boiling resistance; the explosion-proof membrane is low in initial viscosity, high in viscosity after high-temperature thermal activation and good in adhesive property, and has the advantages of reworking and easiness in bubble removal.

Description

Technical Field

[0001] The invention relates to the field of film materials, and in particular to a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover and a preparation method thereof. Background Art

[0002] With the increasing popularity of smart phones, they have developed and improved rapidly not only in function but also in appearance. People's daily lives are becoming more and more inseparable from smart phones, which have become an indispensable part of our daily lives. Based on this, the market for explosion-proof films that provide protection for smart phones has also developed rapidly. Mobile phone explosion-proof films can protect the mobile phone screen from damage when the phone falls or contacts with sharp objects. The price itself is low, but it can bring greater protection effect, so it is widely welcomed by people and has become a standard part of smart phones.

[0003] The explosion-proof film inside the back cover of the mobile phone is a PET protective film that can be used on the glass back cover of the mobile phone battery. Its function is to effectively prevent the back cover or screen of the mobile phone from bursting, and alleviate the glass panel from breaking when the mobile phone collides with other objects.

[0004] Currently, the explosion-proof films for mobile phone battery back covers on the market generally have good adhesive properties, but it is usually difficult to have both good boiling resistance and thermal adhesion performance. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover and a preparation method thereof in view of the deficiencies in the above-mentioned prior art.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover, comprising a substrate layer, an acrylic pressure-sensitive adhesive layer and a release layer stacked in sequence;

[0007] The raw materials for preparing the acrylic pressure-sensitive adhesive layer include a pressure-sensitive adhesive solution and a tackifying resin, wherein the pressure-sensitive adhesive solution includes the following raw material components in parts by weight: 30 to 45 parts by weight of an acrylic soft monomer, 50 to 65 parts by weight of an acrylic hard monomer, 2 to 10 parts by weight of an acrylic functional monomer, and 0.2 to 2 parts by weight of an initiator.

[0008] Preferably, the acrylic soft monomer is octadecyl acrylate.

[0009] Preferably, the acrylic hard monomer is a mixture of one or more of m-phenoxybenzyl acrylate, o-phenylphenoxyethyl acrylate, benzyl acrylate, and isobornyl acrylate.

[0010] Preferably, the acrylic ester functional monomer is one or both of β-acryloxypropionic acid and glycidyl methacrylate.

[0011] Preferably, the acrylic hard monomer is a mixture of m-phenoxybenzyl acrylate or o-phenylphenoxyethyl acrylate, benzyl acrylate and isobornyl acrylate;

[0012] The acrylic ester functional monomer is β-acryloxy propionic acid or a mixture of β-acryloxy propionic acid and glycidyl methacrylate.

[0013] Preferably, the raw materials for preparing the acrylic pressure-sensitive adhesive layer include 90-98 parts by weight of pressure-sensitive adhesive solution and 2-10 parts by weight of tackifying resin.

[0014] Preferably, the tackifying resin is Arakawa 803L terpene resin.

[0015] Preferably, the substrate layer is made of PET and has a thickness of 25-100 μm.

[0016] The present invention also provides a method for preparing the boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover as described above, comprising the following steps:

[0017] S1. Preparation of pressure-sensitive adhesive solution:

[0018] 30-45 parts by weight of acrylate soft monomer, 50-65 parts by weight of acrylate hard monomer, 2-10 parts by weight of acrylate functional monomer and 0.2-2 parts by weight of initiator are mixed, and free radical polymerization is performed at 60-85° C. to form a polymer to obtain a pressure-sensitive adhesive solution;

[0019] S2. Mix 90-98 parts by weight of a pressure-sensitive adhesive solution and 2-10 parts by weight of a tackifying resin, stir evenly, apply the resulting mixture on the surface of the substrate layer to form an acrylate pressure-sensitive adhesive layer, and finally adhere a release layer to the surface of the acrylate pressure-sensitive adhesive layer and dry it to obtain the boiling-resistant, heat-tackifying and explosion-proof film for the mobile phone battery back cover.

[0020] Preferably, the step S1 is specifically:

[0021] S1-1, add 30-45 parts by weight of acrylate soft monomer, 50-65 parts by weight of acrylate hard monomer, and 2-10 parts by weight of acrylate functional monomer into a reaction kettle, stir evenly, heat to above 50° C., and introduce nitrogen into the reaction kettle for 15-60 minutes;

[0022] S1-2, heating to 55-70°C, adding 0.1-0.4 parts by weight of initiator, and reacting for 1-5 hours;

[0023] S1-3, raise the temperature to 71-85°C within 15-60 minutes, add 0.15-0.6 parts by weight of initiator, and react for 1-4 hours;

[0024] S1-4, adding 0.2-0.8 parts by weight of an initiator, reacting at >78° C. for 1-5 hours to obtain the pressure-sensitive adhesive solution.

[0025] The beneficial effects of the present invention are:

[0026] The invention provides an explosion-proof film for a mobile phone battery back cover with thermal viscosity-increasing performance, which also has good hardness, elasticity, temperature and moisture resistance, and cooking resistance; the explosion-proof film of the invention has low initial viscosity, high viscosity after high-temperature thermal activation, good bonding performance, and has the advantages of being reworkable and easy to remove bubbles.

[0027] The explosion-proof film of the present invention has the characteristics of both high boiling resistance and thermal viscosity increase. The high boiling resistance is due to the selection of monomers with good high temperature and high humidity resistance and boiling resistance (meta-phenoxybenzyl methacrylate / o-phenylphenoxyethyl acrylate, benzyl acrylate, glycidyl methacrylate) in the acrylic masterbatch; the high Tg, high hardness, low shrinkage monomer (isobornyl acrylate) in the glue liquid gives the glue liquid a high modulus and high Tg, so that the adhesive has a lower initial viscosity and has the characteristic of thermal activation; the special functional monomer (β-acryloxypropionic acid) in the glue liquid provides the polymer with initial viscosity and helps to further improve the peeling performance after high-temperature thermal activation; further, by adding a small amount of tackifying resin and performing high-temperature thermal activation treatment on the glue layer through a hot pressing process, the product of the present invention has significant thermal viscosity increase characteristics.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a schematic structural diagram of the boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover.

[0030] Description of reference numerals:

[0031] 1—substrate layer; 2—acrylate pressure-sensitive adhesive layer; 3—release layer; DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0033] It should be understood that terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0034] The present invention provides a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover, comprising a substrate layer 1, an acrylate pressure-sensitive adhesive layer 2 and a release layer 3 which are stacked in sequence;

[0035] The raw materials for preparing the acrylic pressure-sensitive adhesive layer include a pressure-sensitive adhesive solution and a tackifying resin, wherein the pressure-sensitive adhesive solution includes the following raw material components in parts by weight: 30 to 45 parts by weight of an acrylic soft monomer, 50 to 65 parts by weight of an acrylic hard monomer, 2 to 10 parts by weight of an acrylic functional monomer, and 0.2 to 2 parts by weight of an initiator.

[0036] In a preferred embodiment, the acrylic soft monomer is octadecyl acrylate. The acrylic hard monomer is a mixture of one or more of m-phenoxybenzyl methacrylate, o-phenylphenoxyethyl acrylate, benzyl acrylate, and isobornyl acrylate. The acrylic functional monomer is one or both of β-acryloxypropionic acid and glycidyl methacrylate.

[0037] In a more preferred embodiment, the acrylate soft monomer is octadecyl acrylate, the acrylate hard monomer is a mixture of m-phenoxybenzyl acrylate or o-phenylphenoxyethyl acrylate, benzyl acrylate and isobornyl acrylate; the acrylate functional monomer is β-acryloxypropionic acid or a mixture of β-acryloxypropionic acid and glycidyl methacrylate.

[0038] In a preferred embodiment, the raw materials for preparing the acrylic pressure-sensitive adhesive layer include 90-98 parts by weight of pressure-sensitive adhesive solution and 2-10 parts by weight of tackifying resin.

[0039] In a preferred embodiment, the tackifying resin is Arakawa 803L terpene resin.

[0040] In a preferred embodiment, the substrate layer is made of PET and has a thickness of 25-100 μm.

[0041] In a preferred embodiment, the thickness of the acrylate pressure-sensitive adhesive layer is 10-50 μm, and the thickness of the release layer is 25-100 μm.

[0042] The present invention also provides a method for preparing the above-mentioned boiling-resistant, heat-adhesive explosion-proof film for the back cover of a mobile phone battery, comprising the following steps:

[0043] S1. Preparation of pressure-sensitive adhesive solution:

[0044] 30-45 parts by weight of acrylate soft monomer, 50-65 parts by weight of acrylate hard monomer, 2-10 parts by weight of acrylate functional monomer and 0.2-2 parts by weight of initiator are mixed, and free radical polymerization is performed at 60-85° C. to form a polymer to obtain a pressure-sensitive adhesive solution;

[0045] S2. Mix 90-98 parts by weight of a pressure-sensitive adhesive solution and 2-10 parts by weight of a tackifying resin, stir evenly, apply the resulting mixture on the surface of the substrate layer to form an acrylate pressure-sensitive adhesive layer, and finally adhere a release layer to the surface of the acrylate pressure-sensitive adhesive layer and dry it to obtain the boiling-resistant, heat-tackifying and explosion-proof film for the mobile phone battery back cover.

[0046] In a preferred embodiment, the step S1 is specifically as follows:

[0047] S1-1, add 30-45 parts by weight of acrylate soft monomer, 50-65 parts by weight of acrylate hard monomer, and 2-10 parts by weight of acrylate functional monomer into a reaction kettle, stir evenly, heat to above 50° C., and introduce nitrogen into the reaction kettle for 15-60 minutes;

[0048] S1-2, heating to 55-70°C, adding 0.1-0.4 parts by weight of initiator, and reacting for 1-5 hours;

[0049] S1-3, raise the temperature to 71-85°C within 15-60 minutes, add 0.15-0.6 parts by weight of initiator, and react for 1-4 hours;

[0050] S1-4, adding 0.2-0.8 parts by weight of an initiator, reacting at >78° C. for 1-5 hours to obtain the pressure-sensitive adhesive solution.

[0051] Detailed examples and comparative examples are provided below to further illustrate the present invention.

[0052] Example 1

[0053] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0054] S1. Preparation of pressure-sensitive adhesive solution:

[0055] S1-1, add 45 parts of octadecyl acrylate (SA, acrylate soft monomer), 20 parts of m-phenoxybenzyl acrylate (MPOBA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 5 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0056] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0057] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0058] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 7890 mPa.s, weight average molecular weight: 1058625.

[0059] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0060] Example 2

[0061] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0062] S1. Preparation of pressure-sensitive adhesive solution:

[0063] S1-1, add 40 parts of octadecyl acrylate (SA, acrylate soft monomer), 25 parts of m-phenoxybenzyl methacrylate (MPOBA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor and mix, stir at high speed to fully mix, and when heated to above 50°C, introduce nitrogen into the reactor for 30 minutes;

[0064] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0065] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0066] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 7431 mPa.s, weight average molecular weight: 985621.

[0067] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0068] Example 3

[0069] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0070] S1. Preparation of pressure-sensitive adhesive solution:

[0071] S1-1, add 35 parts of octadecyl acrylate (SA, acrylate soft monomer), 30 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0072] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0073] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0074] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 6982 mPa.s, weight average molecular weight: 898570.

[0075] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0076] Example 4

[0077] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0078] S1. Preparation of pressure-sensitive adhesive solution:

[0079] S1-1, add 30 parts of octadecyl acrylate (SA, acrylate soft monomer), 35 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0080] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0081] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0082] S1-4, add 0.4 parts by weight of initiator, react at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Test the adhesive solution, viscosity: 6273 mPa.s. Weight average molecular weight: 814147.

[0083] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0084] Example 5

[0085] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0086] S1. Preparation of pressure-sensitive adhesive solution:

[0087] S1-1, add 30 parts of octadecyl acrylate (SA, acrylate soft monomer), 35 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0088] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0089] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0090] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 6273 mPa.s, weight average molecular weight: 814147.

[0091] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0092] Example 6

[0093] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0094] S1. Preparation of pressure-sensitive adhesive solution:

[0095] S1-1, add 30 parts of octadecyl acrylate (SA, acrylate soft monomer), 35 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0096] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0097] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0098] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 6273 mPa.s, weight average molecular weight: 814147.

[0099] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0100] Example 7

[0101] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0102] S1. Preparation of pressure-sensitive adhesive solution:

[0103] S1-1, add 40 parts of octadecyl acrylate (SA, acrylate soft monomer), 25 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor and mix, stir at high speed to fully mix, and when heated to above 50°C, introduce nitrogen into the reactor for 30 minutes;

[0104] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0105] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0106] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 7149 mPa.s, weight average molecular weight: 927483.

[0107] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0108] Comparative Example 1

[0109] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0110] S1. Preparation of pressure-sensitive adhesive solution:

[0111] S1-1, add 65 parts of octadecyl acrylate (SA, acrylate soft monomer), 30 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0112] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0113] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0114] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 6860 mPa.s. Weight average molecular weight: 887543.

[0115] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0116] Comparative Example 2

[0117] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0118] S1. Preparation of pressure-sensitive adhesive solution:

[0119] S1-1, add 45 parts of octadecyl acrylate (SA, acrylate soft monomer), 20 parts of m-phenoxybenzyl methacrylate (MPOBA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 5 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0120] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0121] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0122] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 6542 mPa.s, weight average molecular weight: 844217.

[0123] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0124] Comparative Example 3

[0125] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0126] S1. Preparation of pressure-sensitive adhesive solution:

[0127] S1-1, add 45 parts of octadecyl acrylate (SA, acrylate soft monomer), 20 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 5 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0128] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0129] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0130] S1-4, add 0.4 parts by weight of initiator, react at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Test the adhesive solution, viscosity: 5943 mPa.s. Weight average molecular weight: 761926.

[0131] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0132] Comparative Example 4

[0133] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0134] S1. Preparation of pressure-sensitive adhesive solution:

[0135] S1-1, add 30 parts of octadecyl acrylate (SA, acrylate soft monomer), 35 parts of m-phenoxybenzyl methacrylate (MPOBA, acrylate hard monomer), 30 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0136] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0137] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0138] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 1072 mPa.s, weight average molecular weight: 239822.

[0139] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0140] Comparative Example 5

[0141] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0142] S1. Preparation of pressure-sensitive adhesive solution:

[0143] S1-1, add 30 parts of octadecyl acrylate (SA, acrylate soft monomer), 35 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 30 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor, mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0144] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0145] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0146] S1-4, adding 0.4 parts by weight of initiator, reacting at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Testing the adhesive solution, viscosity: 906 mPa.s, weight average molecular weight: 196209.

[0147] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0148] Comparative Example 6

[0149] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0150] S1. Preparation of pressure-sensitive adhesive solution:

[0151] S1-1, add 450 parts of octadecyl acrylate (SA, acrylate soft monomer), 30 parts of isobornyl acrylate (IBOA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 2 parts of β-acryloxypropionic acid (β-CEA, acrylate functional monomer), 3 parts of glycidyl methacrylate (GMA, acrylate functional monomer) into a reactor and mix, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reactor for 30 minutes;

[0152] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0153] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0154] S1-4, add 0.4 parts by weight of initiator, react at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Test the adhesive solution, viscosity: 4571 mPa.s, weight average molecular weight: 575001.

[0155] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0156] Comparative Example 7

[0157] A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover comprises the following steps:

[0158] S1. Preparation of pressure-sensitive adhesive solution:

[0159] S1-1, add 35 parts of octadecyl acrylate (SA, acrylate soft monomer), 35 parts of o-phenylphenoxyethyl acrylate (OPPEA, acrylate hard monomer), 15 parts of benzyl acrylate (BzA, acrylate hard monomer), 15 parts of isobornyl acrylate (IBOA, acrylate hard monomer) into a reaction kettle, stir at high speed to fully mix, heat to above 50°C, and introduce nitrogen into the reaction kettle for 30 minutes;

[0160] S1-2, heating to 65°C, adding 0.2 parts by weight of AIBN, and reacting for 2.5 hours;

[0161] S1-3, heating to 75°C within 30 minutes, adding 0.3 parts by weight of AIBN, and reacting for 2 hours;

[0162] S1-4, add 0.4 parts by weight of initiator, react at >78°C for 2.5 hours to obtain the pressure-sensitive adhesive solution. Test the adhesive solution, viscosity: 5562 mPa.s. Weight average molecular weight: 744722.

[0163] S2. Mix 97 parts by weight of pressure-sensitive adhesive liquid and 3 parts by weight of Arakawa 803L terpene resin (tackifying resin), stir evenly, and apply the resulting mixture on the surface of a substrate layer with a thickness of 50 μm to form a 25 μm thick acrylate pressure-sensitive adhesive layer. Finally, adhere a 50 μm thick release layer to the surface of the acrylate pressure-sensitive adhesive layer to obtain a sample, which is then dried and tested.

[0164] The samples prepared in Examples 1-7 and Comparative Examples 1-7 were subjected to the following tests:

[0165] Test content:

[0166] (1) 180° peel force test before and after hot pressing:

[0167] Object to be bonded: glass plate; Hot pressing treatment: 80℃, 1MPa, hot pressing for 5min;

[0168] (2) High temperature boiling water resistance test:

[0169] Object: glass plate; Boiling treatment: the sample after hot pressing treatment is boiled in 100℃ boiling water for 2h;

[0170] (3) 180° peel strength test of the sample after boiling in water.

[0171] The test results are shown in Table 1 and Table 2.

[0172] Table 1

[0173]

[0174] Table 2

[0175]

[0176]

[0177] It can be seen from the test results of Table 1 and Table 2 that the products of Examples 1-7 exhibit good resistance to water boiling and high temperature and humidity, and the product performance of Comparative Examples 1-7 has declined significantly, which is mainly attributed to the fact that Comparative Examples 1-7 do not use the solution of preparing the pressure-sensitive adhesive solution by compounding m-phenoxybenzyl acrylate / o-phenylphenoxyethyl acrylate, benzyl acrylate, and β-acryloxypropionic acid.

[0178] In the embodiment of the present invention, m-phenoxybenzyl methacrylate / o-phenylphenoxyethyl acrylate, benzyl acrylate, and β-acryloxy propionic acid are used to prepare a pressure-sensitive adhesive. O-phenylphenoxyethyl acrylate and benzyl acrylate contain a benzene ring structure. Since the π bond in the benzene ring has a stronger rigidity than the freely rotatable single bond, the benzene ring is more stable than the flexible ester bond structure, and the aromatic monomer usually has a stronger water resistance and high temperature and humidity resistance. By introducing o-phenylphenoxyethyl acrylate and benzyl acrylate into the polymer copolymerization unit, the boiling resistance of the polymer can be effectively improved. In addition, during the entanglement between the macromolecular chains, π-π interactions occur between the benzene ring structures in different polymer chains, further enhancing the water resistance and strength of the polymer. β-acryloxy propionic acid has a lower glass transition temperature and can effectively promote adhesion. It has a longer side carboxylic acid chain to give good flexibility, promote better interaction between the polymer and the substrate, thereby enhancing adhesion and peel strength. In the examples of the present invention, β-acryloxypropionic acid is introduced into the polymer unit to provide initial viscosity to the pressure-sensitive adhesive, and is also conducive to a huge increase in viscosity after high-temperature thermal activation, significantly improving the thermal tackification effect.

[0179] The explosion-proof film in the embodiment of the present invention has the characteristics of high boiling resistance and thermal tackification. Its high boiling resistance is due to the selection of monomers with good high temperature and humidity resistance and boiling resistance (meta-phenoxybenzyl methacrylate / o-phenylphenoxyethyl acrylate, benzyl acrylate, glycidyl methacrylate) in the acrylic masterbatch; and the high content of high Tg, high hardness, low shrinkage monomers (isobornyl acrylate) in the glue liquid gives the glue liquid high modulus and high Tg, so that the adhesive has a lower initial viscosity and thermal activation characteristics, and the special functional monomer (β-acryloxypropionic acid) in the glue liquid provides the polymer with initial viscosity and helps to further improve the peeling performance after high-temperature thermal activation. By matching a small amount of tackifying resin and using a hot pressing process to perform high-temperature thermal activation treatment on the adhesive layer, the product of the present invention has significant thermal tackification characteristics (at 80°C, which is higher than the Tg of the acrylic pressure-sensitive adhesive, the flow properties of the pressure-sensitive adhesive are greatly improved, thereby significantly improving the viscosity of the product).

[0180] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A boiling-resistant, heat-adhesive explosion-proof film for mobile phone battery back cover. It is characterized in that It comprises a substrate layer, an acrylate pressure-sensitive adhesive layer and a release layer which are stacked in sequence; The raw materials for preparing the acrylic pressure-sensitive adhesive layer include a pressure-sensitive adhesive solution and a tackifying resin, wherein the pressure-sensitive adhesive solution includes the following raw material components in parts by weight: 30 to 45 parts by weight of an acrylic soft monomer, 50 to 65 parts by weight of an acrylic hard monomer, 2 to 10 parts by weight of an acrylic functional monomer, and 0.2 to 2 parts by weight of an initiator.

2. The boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover according to claim 1, It is characterized in that The acrylic ester soft monomer is octadecyl acrylate.

3. The boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover according to claim 1, It is characterized in that The acrylic ester hard monomer is a mixture of one or more of m-phenoxybenzyl acrylate, o-phenylphenoxyethyl acrylate, benzyl acrylate and isobornyl acrylate.

4. The boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover according to claim 1, It is characterized in that The acrylic ester functional monomer is one or both of β-acryloxy propionic acid and glycidyl methacrylate.

5. The boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover according to claim 2, It is characterized in that The acrylic acid ester hard monomer is a mixture of m-phenoxybenzyl acrylate or o-phenylphenoxyethyl acrylate, benzyl acrylate and isobornyl acrylate; The acrylic ester functional monomer is β-acryloxy propionic acid or a mixture of β-acryloxy propionic acid and glycidyl methacrylate.

6. The boiling-resistant, heat-adhesive explosion-proof film for the back cover of a mobile phone battery according to claim 1, It is characterized in that The raw materials for preparing the acrylic ester pressure-sensitive adhesive layer include 90-98 parts by weight of pressure-sensitive adhesive solution and 2-10 parts by weight of tackifying resin.

7. The boiling-resistant, heat-adhesive explosion-proof film for the back cover of a mobile phone battery according to claim 6, It is characterized in that The tackifying resin is Arakawa 803L terpene resin.

8. The boiling-resistant, heat-adhesive explosion-proof film for the mobile phone battery back cover according to claim 1, It is characterized in that The substrate layer is made of PET and has a thickness of 25-100 μm.

9. A method for preparing a boiling-resistant, heat-adhesive explosion-proof film for a mobile phone battery back cover as claimed in any one of claims 1 to 8, It is characterized in that The following steps are involved: S1. Preparation of pressure-sensitive adhesive solution: 30-45 parts by weight of acrylate soft monomer, 50-65 parts by weight of acrylate hard monomer, 2-10 parts by weight of acrylate functional monomer and 0.2-2 parts by weight of initiator are mixed, and free radical polymerization is performed at 60-85° C. to form a polymer to obtain a pressure-sensitive adhesive solution; S2. Mix 90-98 parts by weight of a pressure-sensitive adhesive solution and 2-10 parts by weight of a tackifying resin, stir evenly, apply the resulting mixture on the surface of the substrate layer to form an acrylate pressure-sensitive adhesive layer, and finally adhere a release layer to the surface of the acrylate pressure-sensitive adhesive layer and dry it to obtain the boiling-resistant, heat-tackifying and explosion-proof film for the mobile phone battery back cover.

10. The method for preparing the boiling-resistant, heat-adhesive explosion-proof film for the back cover of a mobile phone battery according to claim 9, It is characterized in that The step S1 is specifically as follows: S1-1, add 30-45 parts by weight of acrylate soft monomer, 50-65 parts by weight of acrylate hard monomer, and 2-10 parts by weight of acrylate functional monomer into a reaction kettle, stir evenly, heat to above 50° C., and introduce nitrogen into the reaction kettle for 15-60 minutes; S1-2, heating to 55-70°C, adding 0.1-0.4 parts by weight of initiator, and reacting for 1-5 hours; S1-3, raise the temperature to 71-85°C within 15-60 minutes, add 0.15-0.6 parts by weight of initiator, and react for 1-4 hours; S1-4, adding 0.2-0.8 parts by weight of an initiator, reacting at >78° C. for 1-5 hours to obtain the pressure-sensitive adhesive solution.

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