TWI642753B - Optical adhesive product and touch display module and adhering method thereof - Google Patents

Abstract

An optical tape product, a touch display device and a bonding method thereof. Optical tape products are made by the following methods. First, a soft monomer and a hard monomer are blended to form a main agent. Then, a hardener is added to the main agent to blend into an adhesive, wherein the weight percentage of the hardener is between 0.08% and 0.18% of the main agent. Then, an adhesive is applied to a first release film. Then, the adhesive is heated to cure the adhesive. Then, a cured adhesive is attached to a second release film, wherein the cured adhesive is located between the first release film and the second release film.

Description

Optical tape product, touch display device and bonding method thereof

The invention relates to an optical tape product and a touch display device and a method for bonding the same, and in particular to an optical tape product with a hardener and a touch display device and a method for bonding the same.

The traditional method of bonding touch display devices is to use a liquid optical adhesive to bond the touch module and the display module, and then solidify the liquid optical adhesive to fix the touch module and the display module. However, if a bubble problem occurs in the liquid optical adhesive, since the liquid optical adhesive has been cured, after the touch module and the display module are separated, there will be residual glue on the touch module and the display module. It takes a lot of time to remove these glues, resulting in poor reworkability.

Therefore, there is an urgent need to propose a new bonding mechanism for a touch display device that can increase reworkability.

Therefore, the present invention proposes an optical tape product, an optical tape, and a touch display device and a method for bonding the same, which can increase the reworkability of the touch display device.

According to an embodiment of the present invention, an optical tape product is provided. Optical tape products are prepared by the following methods: blending a soft monomer and a hard monomer to form a main agent; adding a first hardener to the main agent to blend into an adhesive, wherein the first hardener The weight percentage is between 0.08% and 0.18% of the main agent; and, coating the adhesive on a first release film; heating the adhesive to cure the adhesive.

According to another embodiment of the present invention, a touch display device is provided. The touch display device includes a touch module, a display module and an adhesive. An adhesive is formed between the touch module and the display module to adhere the touch module and the display module. The adhesive includes a main agent and a first hardener. The main agent includes a soft monomer and a hard monomer. The weight percentage of the first hardener is between 0.08% and 0.18% of the main agent.

According to another embodiment of the present invention, a method for bonding a touch display device is provided. The bonding method includes the following steps. Provide an optical tape product as described above; remove the first release film from the cured adhesive to expose the cured adhesive; adhere the display module and a touch mold with the cured adhesive Group; and, the cured adhesive is irradiated with light, and the cured adhesive is hardened.

In order to have a better understanding of the above and other aspects of the present invention, preferred embodiments are described below in detail with the accompanying drawings, as follows:

10‧‧‧Touch display device

11‧‧‧Display Module

12‧‧‧Touch Module

100‧‧‧chemical tape products

110‧‧‧Adhesive

120‧‧‧The first release film

130‧‧‧Second Release Film

t‧‧‧thickness

Figures 1A to 1C show the manufacturing process of an optical tape product according to an embodiment of the present invention. Cheng Tu

2A and 2D are diagrams illustrating a manufacturing process of a touch display device according to an embodiment of the present invention.

1A to 1C are diagrams illustrating a manufacturing process of an optical tape product according to an embodiment of the present invention.

As shown in FIG. 1A, after the main agent, the first hardener, the second hardener, and the additives are blended, an adhesive 110 is formed. Then, the adhesive 110 is coated on the first release film 120. Hereinafter, the main agent, the first hardener, the second hardener, and additives will be described in detail.

The main agent can be prepared from soft monomers, hard monomers, functional monomers, thermal initiators and photoinitiators.

The soft monomer may be a viscous monomer. The soft monomer is, for example, a polymer which can generate a lower glass transition temperature (Tg) and has an initial viscosity. For example, the soft monomer may be ethyl acrylate, butyl acrylate, isooctyl acrylate, or a combination thereof.

The hard monomer may be a cohesive monomer. The hard monomer is, for example, a homopolymer that can generate a higher glass transition temperature, and the soft monomer can be copolymerized to improve the cohesive strength of the soft monomer and help improve water resistance and adhesion strength. For example, the hard monomer may be vinyl acetate, acryl, acrylamide, styrene, methyl methacrylate, methyl acrylate, or a combination thereof. In an embodiment, the weight percentage of the hard monomer Can account for about 60% of the main agent or adhesive.

The embodiment of the present invention is a double-sided adhesive. In one embodiment, the main agent composition is an acrylic copolymer, and it is difficult to adjust the temperature during the intense exothermic reaction of polymerization. Therefore, some solvents are used as the transfer agent. The heat medium can improve the heat transfer, and the polymerization temperature is easy to control. In one embodiment, the solvent is particularly preferably a toluene having a weight percentage of about 5% to 15% of the main agent or an adhesive and a low boiling point EAC solvent having a weight percentage of about 30% to 60% of the main agent or the adhesive. However, the embodiment of the present invention is not limited thereto.

Functional monomers can be copolymerized with soft monomers and hard monomers to form acrylic acid copolymers with functional groups, and the copolymers can be chemically crosslinked to improve heat resistance and aging resistance. The functional group monomer is, for example, methacrylic acid, acrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, or diaminoethyl hydroxypropyl methacrylate. In one embodiment, the functional monomer may account for more than about 60% by weight of the main agent or the adhesive, but may also be less than 60%.

The thermal initiator is, for example, azobisisobutyronitrile (AIBN) or benzamidine peroxide (BPO). These two thermal initiators are thermally decomposable. After the temperature is increased to reach the decomposition temperature, a molecular initiator will be decomposed into free radical molecules each carrying an electron to start the reaction. Free radicals can attack double bonds on acrylate monomers, and then combine with them to generate free radicals, and then attack the double bonds on an acrylate monomer. This chain reaction continues to make the molecular weight of the polymer continue to increase Until the monomer is consumed, the reaction set is terminated.

The photoinitiator is, for example, an organic peroxide or an azo compound, preferably Aromatic carbonyl compounds, such as phenyl ketone compounds, such as 1,2-diphenylethylene diketone (BenZil), benzophenone (Benzophenone), benzoin (Benzoin), and ether derivatives thereof. The weight percentage of the photoinitiator may be 0.1% to 3% of the main agent.

After the main agent is blended, a first hardener may be added to the main agent, wherein the weight percentage of the first hardener is between 0.08% and 0.18% of the main agent. The first hardener is, for example, a cross-linking hardener. The first hardener can dissolve well in organic solvents and contain highly polar N-HCO-groups, which can wet the substrate or form strong hydrogen bonds and dipolar attractive forces. The first hardener is, for example, a polyisocyanate. As the first hardener, the chemical structure C1 shown below can be used.

In addition, a second hardener and / or an additive may be optionally added to the main agent.

The second hardener has the characteristics of long life, small performance deviation, less yellowing, and good heat resistance. For example, the second hardener is an epoxy compound. Second hardener Examples are compounds such as polyamines or polyanhydrides. The second hardener may be crosslinked with the first hardener. The second hardener has the advantages of an epoxy compound having a long life, small variation in performance, less yellowing, and excellent heat resistance to increase its cohesion (retention). The addition amount of the second hardener is particularly preferably 0 to 1.5 times that of the first hardener. In one embodiment, the second hardener may have a chemical structure C2 as shown below.

The additive can be an organic silicon compound, such as a silane coupling agent, which has a unique bifunctionality, which can promote the combination of organic polymers and the surface of inorganic minerals, so that the composite material retains a certain strength under long-term use. In one embodiment, the weight percentage of the additive may be between 0 and 1 times the first hardener. Additives can use the chemical structure C3 shown below.

As shown in FIG. 1A, an adhesive 110 can be applied on the first release film 120. The coating thickness t of the adhesive 110 may be between 20 micrometers and 350 micrometers.

As shown in FIG. 1B, the adhesive 110 is heated at, for example, about 90 degrees Celsius. About 3 minutes to cure the adhesive 110. Due to the composition of the adhesive 110 described above, the cured adhesive 110 is not completely hardened and still has tackiness, so it can be adhered to a substrate, such as a touch module and / or a display module. In addition, the glass transition temperature of the cured adhesive 110 is in an appropriate range, and therefore has appropriate viscosity. Further, if the glass transition temperature is too low, the adhesiveness is too sticky, which may cause uneven adhesive surface problems after the application; if the glass transition temperature is too high, the adhesiveness is poor. The glass transition temperature of the cured adhesive 110 according to the embodiment of the present invention is between -50 ° C and -40 ° C, and preferably between -48 ° C and -43 ° C. Therefore, it has proper viscosity to make the coating Adhesive surface is uniform and qualified.

As shown in FIG. 1C, the second release film 130 is bonded with the cured adhesive 110, so that the first release film 120, the second release film 130, and the cured adhesive 110 form a chemical tape product 100, The cured adhesive 110 is located between the first release film 120 and the second release film 130. Since the two opposite sides of the adhesive 110 are protected by the first release film 120 and the second release film 130, respectively, the viscosity of the adhesive 110 is not easily affected by the negative external environment, such as moisture or impurities. In one embodiment, a material of the first release film 120 and the second release film 130 may be polyethylene terephthalate (PET).

2A and 2D are diagrams illustrating a manufacturing process of a touch display device 10 according to an embodiment of the present invention.

As shown in FIG. 2A, an optical tape product 100 is provided. The optical tape product 100 includes a cured adhesive 110, a first release film 120 and a second release film 130.

As shown in FIG. 2B, the first release film 120 and the second release film 130 are removed from the cured adhesive 110 to expose the adhesive 110.

As shown in FIG. 2C, the display module 11 and the touch module 12 are adhered with an adhesive 110. In one embodiment, the display module 11 and / or the touch module 12 may include a transparent conductive layer (not shown), such as indium tin oxide (ITO), indium zinc oxide (IZO), and indium gallium zinc oxide. (IGZO) and / or aluminum zinc oxide (AZO), and the adhesive 110 may directly contact the transparent conductive layer.

The embodiment of the present invention is a double-sided adhesive, which has characteristics such as strong initial adhesion, maintaining flexibility in a low-temperature environment, and / or good adhesion at a step. Since the cured adhesive 110 is sticky, the relative position between the display module 11 and the touch module 12 can be fixed. In addition, since the cured adhesive 110 is in a solid state, it is convenient to observe whether the adhesive 110 has a bubble problem. The adhesive 110 at this stage has not been hardened, and therefore has excellent reworkability. In detail, when a poor adhesion is found (such as air bubbles remaining in the adhesive 110), since the adhesive 110 has not been hardened, the display module 11 and the touch module 12 can be easily separated. In addition, since the adhesive 110 has not been hardened, there is little or no residual adhesive on the separated display module 11 and the touch module 12.

As shown in FIG. 2D, the cured adhesive 110 is irradiated with light such as ultraviolet light (UV) to harden the adhesive 110. The adhesive 110 is hardened after being irradiated with ultraviolet light, so the display module 11 and the touch module 12 can be more firmly bonded. The glass transition temperature of the adhesive 110 after UV irradiation is in the range of about -40 ° C to -30 ° C, and the glass transition temperature is particularly preferably in the range of about -35 ° C to -30 ° C.

Please refer to the following tables 1-1 to 1-7, which list the experimental results of the first hardener, the second hardener and the additives in different proportions. For example, the first hardener, second hardener, and The value of the additive is the weight percentage of the main agent. For experimental group 8, the first hardener accounted for 0.08% of the main agent, the second hardener accounted for 0.27% of the main agent, and the additive accounted for 0.18% of the main agent. In addition, the main agent, the first hardener, the second hardener and the additives of the experimental group are described by taking the acrylic pressure-sensitive adhesive, the chemical structures C1, C2, and C3 as examples.

From the results of experimental groups 1 to 8, it can be known that the weight percentage of the first hardener is between 0.08% and 0.18% of the main hardener, and the weight percentage of the second hardener is between 0 and 1.5 times the first hardener. The weight percentage of the additive is between 0 and 1 times of the first hardener. Therefore, the reworkability of the adhesive 110, the letter of trust test, the initial retention force, and the retention force after light exposure (in the table, it is expressed as "retention force after UV") , Adhesion at the beginning, Adhesion after exposure to light (indicated by "Adhesion after UV" in the table), Polarizer compatibility test was passed (determined as "OK").

According to the heavy industry test, the cured adhesive 110 is stuck between the two glasses and rolled back and forth twice with a 2 kg roller to make the adhesive 110 and the glass tightly adhere. After that, the adhesive 110 between the two glasses was separated by a thin line, and then wiped with an EAC solvent to observe the residual gelatinous degree on the glass surface. Due to the composition of the adhesive 110 in this case, the glass hardly has a residue or an amount of residue within an acceptable range (indicated by "OK").

According to the reliability test, after 500 hours of baking at 95 ° C, the adhesive 110 still has qualified optical characteristics (light transmittance is greater than 99% and the degree of fogging is less than 0.5). Between the adhesive 110 and the substrate No peeling phenomenon (indicated by "◎") and no foaming phenomenon.

Table 1-1

According to the reliability test, the adhesive 110 still has qualified optical characteristics (transmittance greater than 99% and fogging degree less than 0.5) after baking for 500 hours under the environment of 80% humidity and 95 degrees Celsius, There is no peeling phenomenon (indicated by “◎”) and no foaming phenomenon (indicated by “◎”) between the adhesive 110 and the substrate.

In terms of initial retention, due to the composition of the adhesive 110, Holding power can exceed 20 minutes. The test method of the initial holding force is tested according to JISZ0237.

In terms of holding power after light irradiation, the holding power after light irradiation exceeds 10,000 minutes due to the composition of the adhesive 110. The test method of the holding force after light irradiation can be the same as that of the initial holding force.

In terms of initial adhesion, due to the composition of the adhesive 110, the initial adhesion can exceed 25 Newtons (N). The initial adhesion test method is based on JIS Z0237.

In terms of adhesion after light irradiation, due to the composition of the adhesive 110, the adhesion force after light irradiation exceeds 40N. The test method for the adhesion after irradiation can be the same as the test method for the initial adhesion.

According to the polarizing plate matching test, the two polarizing films were actually bonded with the adhesive 110 and cured by ultraviolet light, and then baked at 90 degrees Celsius for 500 hours. After baking, it was observed that the adhesive 110 was not foamed (indicated by "◎"), not peeled (indicated by "◎"), and not yellowed (indicated by "◎").

In addition, as can be seen from the above table, the glass transition temperature of the cured adhesive 110 (such as the "normal temperature" column in the table) is between -50 ° C and -40 ° C. After the adhesive 110 is cured by UV, the glass transition temperature decreases to between -40 ° C and -30 ° C. It can be seen that, due to the composition of the adhesive 110 in the embodiment of the present invention, the adhesive 110 does achieve a hardening effect after being irradiated with light. In addition, the effect of hardening after light irradiation can also suppress the occurrence of air bubbles.

In summary, although the present invention has been disclosed as above with preferred embodiments, However, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims (16)

An optical tape product is prepared by the following methods: blending a soft monomer, a hard monomer and a functional monomer to form a main agent, wherein the functional monomer includes diaminoethyl methacrylic acid Hydroxypropyl ester; adding a first curing agent to the main agent to blend into an adhesive; coating the adhesive on a first release film; and heating the adhesive to cure the adhesive. The optical tape product according to item 1 of the scope of patent application, wherein the glass transition temperature of the adhesive after curing is between -50 ° C and -40 ° C. The optical tape product described in item 1 of the scope of patent application, further comprises: bonding the adhesive of a second release film after curing, wherein the adhesive after curing is located between the first release film and the first adhesive film. Between two release films. The optical tape product according to item 1 of the patent application scope, wherein the soft single system ethyl acrylate, butyl acrylate, isooctyl acrylate, or a combination thereof. The optical tape product according to item 1 of the patent application scope, wherein the hard single system vinyl acetate, acrylonitrile, acrylamide, styrene, methyl methacrylate, methyl acrylate, or a combination thereof. The optical tape product according to item 1 of the application, wherein the weight percentage of the first hardener is between 0.08% and 0.18% of the main agent, and / or the first hardener is a polyisocyanate. The optical tape product according to item 1 of the patent application scope, wherein the step of blending the soft monomer and the hard monomer further includes: adding a second hardener to the main agent, wherein the weight of the second hardener is The percentage is between 0 and 1.5 times the first hardener, wherein the second hardener is an epoxy compound. The optical tape product according to item 1 of the patent application scope, wherein the functional group monomer further includes methacrylic acid, acrylic acid, hydroxyethyl methacrylate or hydroxypropyl methacrylate and / or the functional group monomer accounts for The weight percentage of the main agent or the adhesive is more than 60%. The optical tape product described in item 1 of the patent application scope further includes: adding an additive to the main agent, wherein the weight percentage of the additive is between 0 and 1 times the first hardener, wherein the additive is organic Silicon compounds. The optical tape product described in item 1 of the scope of patent application, further includes: adding at least one of a thermal initiator and a light initiator to the main agent. According to the optical tape product described in item 1 of the patent application scope, in the step of applying the adhesive to the first release film, the coating thickness of the adhesive is between 20 micrometers and 350 micrometers. A touch display device includes: a touch module; a display module; and an adhesive formed between the touch module and the display module to adhere the touch module and the display module. Group; wherein the adhesive includes a main agent and a first hardener, the main agent includes a soft monomer, a hard monomer, and a functional monomer, wherein the functional monomer includes a diaminoethyl group Hydroxypropyl methacrylate. The touch display device according to item 12 of the application, wherein the glass transition temperature of the adhesive after curing is between -40 ° C and -30 ° C and / or the thickness of the adhesive is between 20 microns and Between 350 microns. The touch display device according to item 12 of the application, wherein the display module or the touch module further includes a transparent conductive layer, and the adhesive directly contacts the transparent conductive layer. A method for bonding a touch display device includes: providing an optical tape product as described in item 1 of the scope of patent application; removing the first release film from the adhesive after curing to expose the cured film. The adhesive; a display module and a touch module are bonded with the cured adhesive; and the cured adhesive is irradiated with a light to harden the cured adhesive. According to the method for bonding a touch display device according to item 15 of the patent application, wherein the glass transition temperature of the adhesive after curing is between -40 ° C and -30 ° C.