CN116445107A - Adhesive composition, preparation method thereof and display device - Google Patents
Adhesive composition, preparation method thereof and display device Download PDFInfo
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- CN116445107A CN116445107A CN202310454642.8A CN202310454642A CN116445107A CN 116445107 A CN116445107 A CN 116445107A CN 202310454642 A CN202310454642 A CN 202310454642A CN 116445107 A CN116445107 A CN 116445107A
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- 230000001070 adhesive effect Effects 0.000 title claims abstract description 97
- 239000000853 adhesive Substances 0.000 title claims abstract description 95
- 239000000203 mixture Substances 0.000 title claims abstract description 48
- 238000002360 preparation method Methods 0.000 title abstract description 9
- 239000000178 monomer Substances 0.000 claims abstract description 52
- 229920001577 copolymer Polymers 0.000 claims abstract description 40
- 239000012790 adhesive layer Substances 0.000 claims abstract description 38
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 claims abstract description 18
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims abstract description 14
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims abstract description 12
- GOXQRTZXKQZDDN-UHFFFAOYSA-N 2-Ethylhexyl acrylate Chemical compound CCCCC(CC)COC(=O)C=C GOXQRTZXKQZDDN-UHFFFAOYSA-N 0.000 claims abstract description 12
- LNMQRPPRQDGUDR-UHFFFAOYSA-N hexyl prop-2-enoate Chemical compound CCCCCCOC(=O)C=C LNMQRPPRQDGUDR-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000006116 polymerization reaction Methods 0.000 claims description 49
- 238000000034 method Methods 0.000 claims description 24
- 239000003999 initiator Substances 0.000 claims description 22
- 239000010410 layer Substances 0.000 claims description 15
- 239000002904 solvent Substances 0.000 claims description 15
- 238000010438 heat treatment Methods 0.000 claims description 10
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical group N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 claims description 9
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 claims description 6
- 239000004815 dispersion polymer Substances 0.000 claims description 6
- 239000003292 glue Substances 0.000 claims description 6
- 239000011261 inert gas Substances 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 4
- KVILQFSLJDTWPU-UHFFFAOYSA-N heptadecyl prop-2-enoate Chemical compound CCCCCCCCCCCCCCCCCOC(=O)C=C KVILQFSLJDTWPU-UHFFFAOYSA-N 0.000 abstract description 8
- 230000000052 comparative effect Effects 0.000 description 24
- 239000000463 material Substances 0.000 description 14
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 12
- 102200015136 rs398122975 Human genes 0.000 description 12
- 238000012360 testing method Methods 0.000 description 10
- OMIGHNLMNHATMP-UHFFFAOYSA-N 2-hydroxyethyl prop-2-enoate Chemical compound OCCOC(=O)C=C OMIGHNLMNHATMP-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 238000003860 storage Methods 0.000 description 5
- FJKROLUGYXJWQN-UHFFFAOYSA-N 4-hydroxybenzoic acid Chemical compound OC(=O)C1=CC=C(O)C=C1 FJKROLUGYXJWQN-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 3
- -1 acrylic ester Chemical class 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000004132 cross linking Methods 0.000 description 3
- 238000001723 curing Methods 0.000 description 3
- 229920000058 polyacrylate Polymers 0.000 description 3
- 229920000139 polyethylene terephthalate Polymers 0.000 description 3
- 239000005020 polyethylene terephthalate Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 125000005396 acrylic acid ester group Chemical group 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000007870 radical polymerization initiator Substances 0.000 description 2
- 150000003384 small molecules Chemical class 0.000 description 2
- 230000000930 thermomechanical effect Effects 0.000 description 2
- RXQKKPDQYISKHD-UHFFFAOYSA-N 2-ethylhexyl prop-2-enoate;prop-2-enoic acid Chemical compound OC(=O)C=C.CCCCC(CC)COC(=O)C=C RXQKKPDQYISKHD-UHFFFAOYSA-N 0.000 description 1
- OZAIFHULBGXAKX-VAWYXSNFSA-N AIBN Substances N#CC(C)(C)\N=N\C(C)(C)C#N OZAIFHULBGXAKX-VAWYXSNFSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005411 Van der Waals force Methods 0.000 description 1
- 229920006243 acrylic copolymer Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052756 noble gas Inorganic materials 0.000 description 1
- 150000002835 noble gases Chemical class 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000013557 residual solvent Substances 0.000 description 1
- 238000005464 sample preparation method Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J133/04—Homopolymers or copolymers of esters
- C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09J133/062—Copolymers with monomers not covered by C09J133/06
- C09J133/064—Copolymers with monomers not covered by C09J133/06 containing anhydride, COOH or COOM groups, with M being metal or onium-cation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
- C08F220/1808—C8-(meth)acrylate, e.g. isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
- G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
- G09F9/301—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements flexible foldable or roll-able electronic displays, e.g. thin LCD, OLED
Abstract
The present application relates to an adhesive composition comprising a copolymer, the monomer molecules forming the copolymer comprising: 2-ethylhexyl acrylate, n-hexyl acrylate, seventeen branched acrylate, acrylic acid. According to the preparation method, the branched-chain acrylic heptadecyl ester is introduced into monomer molecules forming the adhesive composition, the Tg of the branched-chain acrylic heptadecyl ester is-40 ℃, and the branched-chain acrylic heptadecyl ester is introduced, so that the adhesive force of the adhesive is increased, meanwhile, the lower modulus of an adhesive layer formed by the adhesive can be kept at a low temperature, and the adhesive force and the low-temperature modulus of the adhesive are both in a more ideal state.
Description
Technical Field
The application relates to the field of display, in particular to an adhesive for a display screen.
Background
Currently, with the demand for product diversification, flexible display devices are receiving more and more attention due to their deformable and bendable characteristics. An adhesive layer may be used in a flexible display device to adhere two adjacent materials. The adhesive layer is important as a stress buffer layer, which can help reduce stress in the multilayer film. In order to reduce the stress of the thin film layer, an optical adhesive with a low Young's modulus at a low temperature is used instead of an optical adhesive with a high Young's modulus. The performance of the solvent type acrylic ester pressure-sensitive adhesive is related to the rigidity of the molecular chain of the adhesive, and the stronger the rigidity of the molecular chain of the adhesive is, the better adhesive force and cohesive strength can be shown, thus being beneficial to improving the adhesive force of the adhesive; however, the molecular chain of the adhesive has weak rigidity and strong flexibility, and the adhesive can only show lower Young modulus at low temperature. The compatibility problem of both adhesion and low temperature modulus is not yet solved.
Disclosure of Invention
The embodiment of the application provides an adhesive composition, a preparation method thereof and a display device, so as to solve the compatibility problem of both adhesive force and low-temperature modulus.
In a first aspect, embodiments herein provide an adhesive composition comprising a copolymer, the monomer molecules forming the copolymer comprising: 2-ethylhexyl acrylate, n-hexyl acrylate, seventeen branched acrylate, acrylic acid.
In some embodiments of the present application, the monomer molecules forming the copolymer further comprise: butyl acrylate.
In some embodiments of the present application, the monomer molecules forming the copolymer, in mass percent of the copolymer, include:
in some embodiments of the present application, the monomer molecules forming the copolymer, in mass percent of the copolymer, include:
in a second aspect, embodiments of the present application provide a method for preparing the adhesive composition according to any one of the embodiments of the first aspect, the method comprising the steps of:
providing the monomer molecules, and dissolving the monomer molecules into a solvent to form a pre-polymerization solution;
adding an initiator into the prepolymerization solution to carry out polymerization reaction to obtain polymer dispersion liquid;
removing the solvent of the polymer dispersion to obtain the adhesive composition.
In some embodiments of the present application, the adding an initiator to the pre-polymerization solution for polymerization comprises the steps of:
heating the pre-polymerization solution to a first temperature, adding an initiator into the pre-polymerization solution, and performing constant temperature treatment for a first time after the pre-polymerization solution reaches the first temperature;
and heating the pre-polymerization solution subjected to the constant temperature treatment for a first time to a second temperature and carrying out the constant temperature treatment for a second time.
In some embodiments of the present application, the adding an initiator to the pre-polymerization solution to perform the polymerization reaction before heating the pre-polymerization solution to the first temperature further comprises the steps of:
and introducing inert gas into the prepolymerization solution.
In some embodiments of the present application, the first temperature is 63-67 ℃; and/or the number of the groups of groups,
the first time is 3-5h; and/or the number of the groups of groups,
the second temperature is 73-77 ℃; and/or the number of the groups of groups,
the second time is 2-4h; and/or the number of the groups of groups,
the initiator is azobisisobutyronitrile.
In a third aspect, embodiments of the present application provide an adhesive layer formed by curing the adhesive composition of any of the embodiments of the first aspect.
In some embodiments of the present application, the adhesive layer has a thickness of 40-60um.
In a fourth aspect, embodiments of the present application provide a display device including the adhesive layer according to any one of the embodiments of the third aspect.
In some embodiments of the present application, the display device includes:
a support layer;
a glue layer;
a display screen;
the adhesive layer;
a first cover plate;
the adhesive layer;
and a second cover plate.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the adhesive composition, the preparation method and the display device thereof, the branched seventeen acrylate is introduced into the monomer molecules forming the adhesive composition, the Tg of the branched seventeen acrylate is-40 ℃, and the introduction of the branched seventeen acrylate can enable the adhesive layer formed by the adhesive to keep lower modulus at low temperature while increasing the adhesive force of the adhesive, so that the adhesive force and the low-temperature modulus of the adhesive can reach ideal states.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a schematic flow chart of a method for preparing an adhesive composition according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a display device according to an embodiment of the present application;
FIG. 3 is a FT-IR test chart of example 4 of the application;
fig. 4 is a dynamic thermo-mechanical analysis test chart of example 4 and comparative example 1 of the present application.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.
Unless specifically stated otherwise, the terms used herein should be understood as meaning as commonly used in the art. Thus, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, the present specification will control.
Unless specifically indicated otherwise, the various raw materials, reagents, instruments, equipment, and the like used in this application are commercially available or may be prepared by existing methods.
The meaning of the english abbreviations referred to in this application is as follows:
EHA 2-ethylhexyl acrylate
HA n-hexyl acrylate
BA butyl acrylate
C17A branched heptadecyl acrylate
4-HBA hydroxyethyl acrylate
AA acrylic acid
AIBN azo-bis-isobutyronitrile
There are problems with the compatibility of adhesion and low temperature modulus in adhesives for flexible display devices.
The technical scheme provided by the embodiment of the application aims to solve the technical problems, and the overall thought is as follows:
in a first aspect, embodiments herein provide an adhesive composition comprising a copolymer, the monomer molecules forming the copolymer comprising: 2-ethylhexyl acrylate, n-hexyl acrylate, seventeen branched acrylate, acrylic acid.
As will be appreciated by those skilled in the art, the major component of the flexible screen adhesive may be selected from the group consisting of polyacrylate copolymers. The copolymer is polyacrylate copolymer. For polyacrylate copolymers, the molecular chain stiffness tends to have a better positive correlation with the glass transition temperature (Tg), with higher Tg indicating better adhesive molecular chain stiffness.
The Tg of the monomer of the 2-ethylhexyl acrylate is-70 ℃, the flexibility is high, and the 2-ethylhexyl acrylate can provide initial fluidity and wettability for the flexible screen adhesive as a monomer.
The Tg of the monomer of the n-hexyl acrylate is-50 ℃, the flexibility is higher, and the branched chain is shorter, so that the low-temperature modulus is reduced.
Acrylic acid belongs to a functional monomer, and has carboxyl groups, wherein the carboxyl groups can provide crosslinking sites, so that the adhesive force of the flexible screen adhesive is improved.
It will be appreciated by those skilled in the art that the monomer molecules of the copolymer generally include an adhesion-increasing component in addition to 2-ethylhexyl acrylate, n-hexyl acrylate, acrylic acid. The usual component is typically hydroxyethyl acrylate. The surface of the hydroxyethyl acrylate contains polar functional groups, so that the polarity of the copolymer can be increased, the van der Waals force between the adhesive and the surface to be bonded can be increased, and the adhesive force of the adhesive can be increased.
Hydroxyethyl acrylate is not selected, but branched seventeen acrylate is selected. The branched seventeen acrylate has long molecular chain, can regulate the crosslinking degree of the copolymer, is favorable for increasing the fluidity of the adhesive, and thus increases the contact area between the adhesive and the surface to be bonded, and has the function of increasing the adhesion of the adhesive.
In addition, the Tg of the branched seventeen acrylate is-40 ℃, and the introduction of the branched seventeen acrylate can ensure that the adhesive layer formed by the adhesive can keep lower modulus at low temperature while increasing the adhesive force of the adhesive.
The adhesive composition described herein may contain only the copolymer; the copolymer and a small amount of other auxiliary agents can also be contained; may also contain a solvent.
In the case where the adhesive composition contains a solvent, as an example, the polymerization of the copolymer may be performed in a solution, and after the completion of the polymerization in a solution, the solvent is removed to obtain a substance which may contain a small amount of residual solvent small molecules in addition to the copolymer; as another example, the adhesive composition may be a mixture of the copolymer and an ester solvent.
In addition, in the case where the adhesive composition is a mixture of the copolymer and an ester solvent, some of the embodiments may be used as an adhesive. As an example, the copolymer was combined with ethyl acetate according to 1: after being mixed according to the mass ratio of 1, the obtained mixed liquid can be directly applied to the surface of a material to be solidified to form an adhesive layer, so that an adhesive effect is achieved.
According to the preparation method, the branched-chain acrylic heptadecyl ester is introduced into monomer molecules forming the adhesive composition, the Tg of the branched-chain acrylic heptadecyl ester is-40 ℃, and the branched-chain acrylic heptadecyl ester is introduced, so that the adhesive force of the adhesive is increased, meanwhile, the lower modulus of an adhesive layer formed by the adhesive can be kept at a low temperature, and the adhesive force and the low-temperature modulus of the adhesive are both in a more ideal state.
In some embodiments of the present application, the monomer molecules forming the copolymer further comprise: butyl acrylate.
In the copolymer, structural units formed by butyl acrylate have shorter branched chains, and the branched chains are less entangled, so that the low-temperature modulus of the copolymer is reduced.
In some embodiments of the present application, the monomer molecules forming the copolymer, in mass percent of the copolymer, include:
the molecular chain segment formed after polymerization of the 2-ethylhexyl acrylate has high flexibility and longer branched chain, which is beneficial to
In some embodiments of the present application, the monomer molecules forming the copolymer, in mass percent of the copolymer, include:
in a second aspect, embodiments of the present application provide a method for preparing the adhesive composition according to any one of the embodiments of the first aspect, referring to fig. 1, the method includes the following steps:
s1: providing the monomer molecules, and dissolving the monomer molecules into a solvent to form a pre-polymerization solution;
s2: adding an initiator into the prepolymerization solution to carry out polymerization reaction to obtain polymer dispersion liquid;
s3: removing the solvent of the polymer dispersion to obtain the adhesive composition.
It will be appreciated that the preparation method described is carried out in dependence on the embodiments of the first aspect. The provision of the monomer molecules described in step S1, the kind and the ratio of the monomer molecules are the same as those of the limitations in the first aspect.
It will be appreciated by those skilled in the art that in step S2, the initiator is typically a radical polymerization initiator. One skilled in the art can select a suitable radical polymerization initiator based on the knowledge known in the art. In step S2, one skilled in the art can select known methods and conditions for polymerization of the acrylic copolymer.
It will be appreciated by those skilled in the art that in step S3, the method for removing the solvent may be a conventional method in the art, such as drying, evaporating, centrifugal filtration, etc.
It will be appreciated by those skilled in the art that when the adhesive composition is a mixture of the copolymer and a solvent, the adhesive composition prepared in step S3 may be mixed with a solvent to obtain a mixture of the copolymer and a solvent.
It will be appreciated that the preparation method described may be used to prepare the adhesive composition described in any of the embodiments of the first aspect of the present application, but is not the only method of preparing the adhesive composition. Other methods of preparation may also be selected by those skilled in the art according to conventional techniques in the art.
In some embodiments of the present application, in step S2, the adding an initiator to the pre-polymerization solution to perform a polymerization reaction includes the steps of:
s21: heating the pre-polymerization solution to a first temperature, adding an initiator into the pre-polymerization solution, and performing constant temperature treatment for a first time after the pre-polymerization solution reaches the first temperature;
s22: and heating the pre-polymerization solution subjected to the constant temperature treatment for a first time to a second temperature and carrying out the constant temperature treatment for a second time.
The above scheme controls the temperature in the polymerization process to be a first temperature and a second temperature respectively in time sequence. In step S21, the initiator is newly added into the prepolymerization solution, and a large amount of monomers exist in the prepolymerization solution, so that the active sites of polymerization reaction are more, and the reaction rate is faster, therefore, the temperature of the prepolymerization solution needs to be controlled in a reasonable range, and the reaction rate is prevented from being too fast, and even the explosion polymerization phenomenon occurs. In step S22, the initiator is not increased any more, and the pre-polymerization solution, in which a large number of long-chain copolymer macromolecules have been present and small molecules are present in the form of multimers, has been subjected to a first time at the first temperature, the active sites of the polymerization reaction are greatly reduced compared to when step S21 is performed, and the reaction rate is thus greatly slowed down. Heating the pre-polymerization solution from the first temperature to the second temperature is therefore advantageous for increasing the reaction rate.
In some embodiments of the present application, the adding an initiator to the pre-polymerization solution to perform the polymerization reaction before heating the pre-polymerization solution to the first temperature further comprises the steps of:
s210: and introducing inert gas into the prepolymerization solution.
The purpose of introducing an inert gas into the prepolymerization solution is to prevent oxygen from interfering with the polymerization reaction. The inert gas may be any gas that does not affect the polymerization reaction, such as nitrogen, noble gases.
In some embodiments of the present application, the first temperature is 63-67 ℃; and/or the number of the groups of groups,
the first time is 3-5h; and/or the number of the groups of groups,
the second temperature is 73-77 ℃; and/or the number of the groups of groups,
the second time is 2-4h; and/or the number of the groups of groups,
the initiator is azobisisobutyronitrile.
In step S21, an initiator is newly added into the pre-polymerization solution, and a large amount of monomers exist in the pre-polymerization solution, so that the active sites of polymerization reaction are more, and the reaction rate is faster, and therefore, the temperature of the pre-polymerization solution needs to be controlled in the range of 63-67 ℃; in step S22, although the increase in temperature is advantageous in increasing the reaction rate, the second temperature is controlled in the range of 73 to 77 ℃ because the adhesive composition to be prepared needs to be further cured to exert the adhesive effect when it is used for the adhesive of the flexible display panel later, and thus the degree of crosslinking is not too high.
In a third aspect, embodiments of the present application provide an adhesive layer formed by curing the adhesive composition of any of the embodiments of the first aspect.
It will be readily appreciated that in forming the adhesive layer with the adhesive composition, it is necessary to formulate the adhesive composition into an adhesive and then form the adhesive layer with the adhesive. The method for preparing the adhesive composition into the adhesive is generally to mix the adhesive composition with a solvent, apply the obtained adhesive on the surface of a material, and then cure and dry the material to obtain the adhesive layer.
In some embodiments of the present application, the adhesive layer has a thickness of 40-60um.
The thickness of the adhesive layer is a conventional parameter in the art and is typically set based on the area of the flexible display screen and the thickness of the other layers of the flexible display screen. The above thickness ranges are generally applicable to more common flexible screens, such as flexible cell phone screens; in the case of unconventional flexible screen application, such as a large-area display screen that can be attached to an arc wall, the thickness of the adhesive layer is not limited to the above parameter range, but a reasonable thickness range should be selected according to practical application needs.
In a fourth aspect, embodiments of the present application provide a display device including the adhesive layer according to any one of the embodiments of the third aspect.
The display device comprises a flexible display device; it will be readily appreciated that the adhesive layers described herein are not only suitable for flexible display devices, nor do their lower modulus at low temperatures provide a good result in flexible display devices. As an example, a display screen used in severe cold weather may have a large difference in expansion coefficient between materials of layers, and may easily generate high interlayer stress at an extremely low temperature. Such high interlayer stresses are advantageously relieved by the use of the adhesive layer described herein.
In some embodiments of the present application, referring to fig. 2, the display device includes:
a support layer 1;
a glue layer 2;
a display screen 3;
the adhesive layer 4;
a first cover plate 5;
the adhesive layer 6;
a second cover plate 7.
As will be appreciated by those skilled in the art, the support layer 1 is used to provide support for the display screen, and the support layer 1 is connected with the display screen through the adhesive layer 2; the second cover plate 7 is arranged on the display screen, the first cover plate 5 is arranged between the second cover plate 7 and the display screen 3, and the first cover plate 5 is connected with the display screen 3 and the second cover plate 7 through the adhesive layer 4. The first cover plate 5 serves to protect the display screen 3.
In some embodiments of the present application, the material of the support layer 1 may be one of etched steel plate and carbon fiber plate.
In some embodiments of the present application, the material of the glue layer 2 may be optically transparent glue.
In some embodiments of the present application, the material of the first cover plate 5 and the second cover plate 7 may be one of CPI, PET, UTG, TPU and the like.
The present application is further illustrated below in conjunction with specific embodiments. It should be understood that these examples are illustrative only of the present application and are not intended to limit the scope of the present application. The experimental procedures, which are not specified in the following examples, are generally determined according to national standards. If the corresponding national standard does not exist, the method is carried out according to the general international standard, the conventional condition or the condition recommended by the manufacturer.
Example 1
The present example provides an adhesive composition prepared by the following method:
adding an acrylic monomer and ethyl acetate into a four-necked flask, mechanically stirring, and introducing nitrogen;
dissolving an initiator in an ethyl acetate solution to obtain an initiator solution;
raising the temperature of the four-neck flask to 65 ℃, dropwise adding the initiator solution into the flask by using a constant pressure funnel, and keeping the temperature of the four-neck flask at 65 ℃ for 4 hours;
raising the temperature of the four-neck flask to 75 ℃, keeping the constant temperature for 3 hours, cooling to room temperature, and pouring out the product;
the obtained product was put in a vacuum oven for 12 hours to obtain an adhesive composition.
In this embodiment, the acrylate monomers are: the mass percentages of the acrylic acid-2-ethylhexyl acrylate, n-hexyl acrylate, branched seventeen acrylate and acrylic acid based on the total mass of the acrylic acid ester monomers are shown in table 1.
Example 2
This embodiment differs from embodiment 1 only in that:
the mass percentages of each monomer are different and are shown in Table 1.
Example 3
This embodiment differs from embodiment 1 only in that:
the mass percentages of each monomer are different and are shown in Table 1.
Example 4
This embodiment differs from embodiment 1 only in that:
in this embodiment, the acrylate monomers are: 2-ethylhexyl acrylate, n-hexyl acrylate, seventeen branched acrylate, and acrylic acid, wherein the mass percentages of each monomer are shown in Table 1.
Example 5
This embodiment differs from embodiment 4 only in that:
the mass percentages of each monomer are different and are shown in Table 1.
Example 6
This embodiment differs from embodiment 4 only in that:
the mass percentages of each monomer are different and are shown in Table 1.
Comparative example 1
This comparative example differs from example 1 only in that:
in this comparative example, the acrylate monomers were: 2-ethylhexyl acrylate, n-hexyl acrylate, hydroxyethyl acrylate, branched seventeen acrylate and acrylic acid, wherein the mass percent of each monomer is shown in table 1.
Comparative example 2
This comparative example differs from comparative example 1 only in that:
the mass percentages of each monomer are different and are shown in Table 1.
Comparative example 3
This comparative example differs from comparative example 1 only in that:
the mass percentages of each monomer are different and are shown in Table 1.
Related experiment and effect data:
first, table 1 is provided. Table 1 records the mass percentages of each monomer in examples 1 to 6 and comparative examples 1 to 3, based on the total mass of the acrylic monomers.
TABLE 1
The present application also conducted FT-IR tests on the adhesive composition in example 4. Referring to fig. 3, fig. 3 shows the test result of the FT-IR test.
As can be seen from FIG. 3, about 2959cm-1 and 2933cm-1 are the asymmetric telescopic vibration absorption peaks of methyl and methylene C-H, about 2874cm-1 is the reversely symmetric telescopic vibration absorption peak of methyl C-H, the telescopic vibration peak of C=O appears at 1733cm-1, the absorption of the peak is sharp, the intensity is large, the 1458cm-1 and 1380cm-1 are the telescopic vibration absorption peaks of methyl, and 1244cm-1 and 1165cm-1 are the characteristic absorption peaks of C-O-C. There is a broad peak at 3200cm-1 to 3600cm-1, which is formed by overlapping N-H stretching vibration peak in acrylamide and O-H stretching vibration peak in acrylic acid. In view of the above, it is considered that the acrylic acid ester undergoes copolymerization to form a copolymer.
The adhesive compositions obtained in examples 1 to 6 and comparative examples 1 to 3 were also tested for adhesion and storage modulus of elasticity. In order to perform the above-described test on the adhesive composition, the adhesive composition is first prepared.
The sample preparation method comprises the following steps:
the adhesive compositions of the examples or comparative examples were mixed with ethyl acetate according to a ratio of 1:1, the mass ratio is fully and uniformly mixed, the glue solution is coated on the polyethylene terephthalate film, a flat plate coater is used for coating, and curing and drying are carried out in an oven for 3min, so that an adhesive layer is formed on the polyethylene terephthalate film, and the thickness of the adhesive layer is controlled at 50um; and then taking out the sample, sticking an anti-sticking film, and cutting the sample into standard sample strips to be tested.
The test was carried out according to the national standard GB 2792-1998. The data obtained are shown in Table 2.
TABLE 2
In tables 1 and 2, the respective english abbreviations correspond to the following components:
EHA 2-ethylhexyl acrylate
HA n-hexyl acrylate
BA butyl acrylate
C17A branched heptadecyl acrylate
4-HBA hydroxyethyl acrylate
AA acrylic acid
From tables 1 and 2, it can be seen that:
for example 1, the mass percent of C17A was 5%. In comparative example 1, component C17A was not selected, the mass percentage of 4-HBA selected was 5%, and the mass percentages of the other components were exactly the same as in example 1. Comparative example 2 and example 2, comparative example 3 and example 3 are also 4-HBA replaced C17A in the same mass percent. From the results, the adhesion was improved in each of examples 1 to 3 compared with comparative examples 1 to 3, which is apparently due to the choice of component C17A for examples 1 to 3. This is probably because C17A has better wettability, and the contact area with the material can be increased at the time of bonding, thereby increasing the peeling force between the cover plate material and the adhesive. In addition, examples 1-3 were also reduced in storage modulus in one-to-one comparison with comparative examples 1-3, and the magnitude of the reduction was greater with reduced test temperature, probably because the C17A monomer had a lower Tg point and therefore a lower modulus at low temperatures than the 4 HBA. The magnitude of the decrease in storage modulus of elasticity also showed a tendency to increase with the increase in mass percent of C17A, which also demonstrates that the content of C17A has a significant effect on the storage modulus of elasticity of the adhesive layer at low temperatures.
For example 4, the mass percent of BA was 20% and the mass percent of 2-EHA was 54%. Whereas in example 1 no BA component was added, the mass percentage of 2-EHA was 74%. Example 4 thus corresponds to 20% of the 2-EHA replaced by 20% of BA as compared to example 1. Similarly, example 5 also replaced 20% of the 2-EHA with 20% of BA as compared to example 2 and example 6 as compared to example 3. Examples 4-6 are compared with examples 1-3 one by one, and the adhesion is also improved to some extent. Examples 4 to 6 are compared with examples 1 to 3 one by one, and the storage modulus of elasticity is lowered at-30℃and-20℃and raised at 25℃and 65 ℃. This is probably because BA belongs to short chain acrylate monomers with less side chain entanglement at low temperature and lower low temperature modulus than long chain monomers. The long side chain monomer slides more easily than the short linear monomer under high temperature conditions, resulting in greater loss of high temperature modulus of the long side chain monomer.
From the above, it is known that the addition of C17A can reduce the low-temperature modulus while increasing the adhesion of the adhesive layer. Further addition of BA again can further increase the adhesion of the adhesive layer and reduce the low temperature modulus.
The present application also conducted dynamic thermo-mechanical analysis tests on example 4 and comparative example 1, and the test results are shown in fig. 4.
In fig. 4, G' is the elastic modulus, and Tan σ is the loss factor. As is clear from fig. 4, the elastic modulus of example 4 is significantly lower than that of comparative example 1 at low temperature, and shows a tendency that the difference between the elastic moduli of example 4 and comparative example 1 is increased as the temperature is lowered. This illustrates that example 4, when C17A and BA were added, has a lower elastic modulus at low temperature and is more suitable for flexible screens than comparative example 1.
The magnitude of the loss factor represents the viscoelasticity performance of the material, and the smaller the loss factor is, the larger the elasticity of the material is, the stronger the elastic deformation resistance of the material against external force is, and the material is not easy to deform and lose efficacy. As can be seen from fig. 4, the loss factor of example 4 is slightly lower than that of comparative example 1 at low temperature, but the loss factor of example 4 is significantly higher than that of comparative example 1 at normal temperature and high temperature, and the viscoelastic properties of example 4 are more suitable for flexible screens as a whole.
Various embodiments of the present application may exist in a range format; it should be understood that the description in a range format is merely for convenience and brevity and should not be interpreted as a rigid limitation on the scope of the application. It is therefore to be understood that the range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, wherever applicable. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.
In this application, unless otherwise indicated, terms of orientation such as "upper" and "lower" are used specifically to refer to the orientation of the drawing in the figures. In addition, in the description of the present application, the terms "include", "comprise", "comprising" and the like mean "including but not limited to". Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element. Relational terms such as "first" and "second", and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Herein, "and/or" describing an association relationship of an association object means that there may be three relationships, for example, a and/or B, may mean: a alone, a and B together, and B alone. For the association relation of more than three association objects described by the "and/or", it means that any one of the three association objects may exist alone or any at least two of the three association objects exist simultaneously, for example, for a, and/or B, and/or C, any one of the A, B, C items may exist alone or any two of the A, B, C items exist simultaneously or three of the three items exist simultaneously. Herein, "at least one" means one or more, and "a plurality" means two or more. "at least one", "at least one" or the like refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.
The foregoing is merely a specific embodiment of the application to enable one skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (12)
1. An adhesive composition comprising a copolymer, wherein monomer molecules forming the copolymer comprise: 2-ethylhexyl acrylate, n-hexyl acrylate, seventeen branched acrylate, acrylic acid.
2. The adhesive composition of claim 1, wherein the monomer molecules forming the copolymer further comprise: butyl acrylate.
3. The adhesive composition of claim 1, wherein the monomer molecules forming the copolymer, in mass percent of the copolymer, comprise:
4. the adhesive composition of claim 3, wherein the monomer molecules forming the copolymer, in mass percent of the copolymer, comprise:
5. the method of preparing an adhesive composition according to any one of claims 1 to 4, wherein the method comprises the steps of:
providing the monomer molecules, and dissolving the monomer molecules into a solvent to form a pre-polymerization solution;
adding an initiator into the prepolymerization solution to carry out polymerization reaction to obtain polymer dispersion liquid;
removing the solvent of the polymer dispersion to obtain the adhesive composition.
6. The method of preparing an adhesive according to claim 5, wherein the adding an initiator to the pre-polymerization solution for polymerization comprises the steps of:
heating the pre-polymerization solution to a first temperature, adding an initiator into the pre-polymerization solution, and performing constant temperature treatment for a first time after the pre-polymerization solution reaches the first temperature;
and heating the pre-polymerization solution subjected to the constant temperature treatment for a first time to a second temperature and carrying out the constant temperature treatment for a second time.
7. The method of preparing an adhesive according to claim 6, wherein said adding an initiator to said pre-polymerization solution for polymerization reaction before heating said pre-polymerization solution to a first temperature, further comprises the steps of:
and introducing inert gas into the prepolymerization solution.
8. The method of preparing an adhesive according to claim 6, wherein the first temperature is 63-67 ℃; and/or the number of the groups of groups,
the first time is 3-5h; and/or the number of the groups of groups,
the second temperature is 73-77 ℃; and/or the number of the groups of groups,
the second time is 2-4h; and/or the number of the groups of groups,
the initiator is azobisisobutyronitrile.
9. An adhesive layer, characterized in that the adhesive layer is formed by curing the adhesive composition according to any one of claims 1 to 4.
10. The adhesive layer of claim 9, wherein the adhesive layer has a thickness of 40-60um.
11. A display device comprising the adhesive layer of claim 10.
12. The display device according to claim 11, wherein the display device comprises a bottom-up stack arrangement:
a support layer;
a glue layer;
a display screen;
the adhesive layer;
a functional film layer;
the adhesive layer;
and a cover plate.
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| CN202310454642.8A CN116445107A (en) | 2023-04-25 | 2023-04-25 | Adhesive composition, preparation method thereof and display device |
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