CN115232566A

CN115232566A - Multi-layer adhesive tape and preparation method thereof

Info

Publication number: CN115232566A
Application number: CN202110436103.2A
Authority: CN
Inventors: 殷冠南
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2022-10-25
Also published as: WO2022224083A1

Abstract

The invention relates to a multilayer structure adhesive tape with a carbon nano tube antistatic layer and a preparation method thereof. The multilayer structure adhesive tape comprises an adhesive tape base material layer, and an antistatic layer and an adhesive layer which are positioned on two opposite sides of the adhesive tape base material layer, wherein the antistatic layer comprises single-wall or double-wall carbon nanotubes. The multilayer structure adhesive tape has excellent antistatic ability and optical performance, and the antistatic ability is not easy to be deteriorated with time due to conditions of ultraviolet exposure, oxidation, humidity or high temperature and the like.

Description

Multi-layer adhesive tape and preparation method thereof

Technical Field

The present invention relates to an antistatic device. More particularly, the present invention relates to a multilayered adhesive tape having a carbon nanotube antistatic layer and a method for preparing the same.

Background

Optical films with antistatic layers are widely used, for example, on the surfaces of electronic devices and electronic devices, such as OLED liquid crystal display surfaces, etc., to protect the surfaces of electronic devices during processing and prevent damage to electronic circuits due to the generation of static electricity. It is generally desirable that such optical films have both excellent antistatic properties and optical properties (at least excellent optical clarity) and that the properties do not degrade over time due to conditions such as uv exposure, oxidation, moisture or high temperature.

Two types of conventional coatings are currently used to impart antistatic properties to film surfaces, one based on ionic liquid materials and the other based on conductive polymers. These two coatings each have advantages and limitations. Most of the ionic liquid is colorless, so that the ionic liquid has better optical transparency, and the performance of the ionic liquid is more stable and is not easy to deteriorate. However, carriers of ionic liquids are ions, and thus it is difficult to achieve high conductivity or low surface resistance, and relatively large surface resistance does not provide a sufficient antistatic effect. The carrier of a conductive polymer is a p electron, and the conductivity depends on the conjugated structure of the polymer. Therefore, the conductive polymer may exhibit lower surface resistance and higher conductivity compared to the ionic liquid, and thus provide excellent antistatic ability. In contrast, ionic liquids with mass concentrations as high as 1% typically only achieve surface resistances of 10 < SP > 9 </SP > hm/sq, while conductive polymers typically achieve surface resistances of 10 < SP > 3 </SP > hm/sq. However, the conductive polymer is sensitive to ultraviolet rays, oxygen, or high temperature, and its physicochemical properties are easily deteriorated.

In contrast, carbon nanomaterials (such as carbon nanotubes, graphene, etc.) combine the advantages of both materials, i.e., excellent conductivity based on conjugated structures and stable physicochemical properties. Therefore, the carbon nanomaterial naturally becomes one of ideal choices for eliminating static electricity. At present, the challenges in applying carbon nanomaterials to applications such as OLED liquid crystal displays are mainly how to uniformly disperse the carbon nanomaterials in a certain solvent, how to uniformly apply a coating, and how to minimize the influence of the darker color of the carbon nanomaterials themselves on the optical performance. The invention aims to overcome the challenges in the prior art and apply the carbon nano material to the antistatic optical film on the surface of the electronic equipment.

Disclosure of Invention

The invention aims to provide a multi-layer adhesive tape which has excellent antistatic capability and optical performance, has stable performance and is not easy to deteriorate. It is another object of the present invention to overcome the above-mentioned challenges in the prior art in applying carbon nanomaterials to antistatic optical films.

According to one aspect of the present invention, there is provided a multilayered structure tape including a tape base layer, and an antistatic layer and an adhesive layer on opposite sides of the tape base layer, wherein the antistatic layer includes single-wall or double-wall carbon nanotubes.

The carbon nanotube has low surface resistance and stable physicochemical properties, thereby providing excellent and stable antistatic ability. In addition, unlike multi-walled carbon nanotubes, single-walled or double-walled carbon nanotubes can minimize the influence of the color of the carbon nanotubes themselves on the optical properties of the multilayer structure tape while ensuring excellent antistatic ability.

In one embodiment, the antistatic layer is formed by coating an aqueous dispersion solution comprising single-or double-walled carbon nanotubes and a water-soluble or water-dispersible binder on one side of a tape substrate layer and drying. The water-soluble or water-dispersible binder helps the carbon nanotubes to be uniformly dispersed in the aqueous dispersion solution.

In one embodiment, the thickness of the antistatic layer is less than 80nm to ensure good optical performance.

In one embodiment, the adhesive layer comprises a polyurethane adhesive.

In one embodiment, the adhesive layer has a peel force of less than 15g/inch. The lower peel force can protect the surface to which the multilayer structure tape is adhered (e.g., the surface of an OLED liquid crystal display) and the multilayer structure tape itself from damage when peeled.

In one embodiment, the adhesive layer comprises a plasticizer. The addition of the plasticizer can further reduce the peel force of the adhesive layer to achieve the desired viscosity.

In one embodiment, the multi-layered structure adhesive tape further includes a release film covering the adhesive layer to protect the adhesive layer before use.

According to another aspect of the present invention, there is provided a method of preparing a multilayer-structured adhesive tape including an adhesive tape base layer. The method comprises the following steps: preparing a binder solution; preparing an aqueous dispersion solution comprising single-walled or double-walled carbon nanotubes; coating the aqueous dispersion solution on one side of the adhesive tape base material layer and drying to form an antistatic layer; coating the adhesive solution on the other side of the adhesive tape base material layer, and drying and curing to form an adhesive layer; and post-curing the adhesive layer.

In one embodiment, the aqueous dispersion solution comprises a water-soluble or water-dispersible binder.

In one embodiment, the antistatic layer is formed to a thickness of less than 80nm.

In one embodiment, the adhesive layer is formed using a polyurethane adhesive.

In one embodiment, the adhesive layer is formed to have a peel force of less than 15g/inch.

In one embodiment, further comprising laminating a release film on the adhesive layer.

As described above, the present invention realizes a multilayered adhesive tape having both excellent antistatic ability and optical performance and stable performance without deterioration by forming an antistatic layer with single-walled or double-walled carbon nanotubes, and achieves superior performance to conventional ionic liquid antistatic layers and conductive polymer antistatic layers. In addition, the present invention can achieve uniform dispersion and coating of carbon nanotubes by forming an antistatic layer by a method of coating with an aqueous dispersion solution, thereby forming a uniform antistatic layer.

Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings. In the drawings, like features or components are denoted by like reference numerals, and the drawings are not necessarily drawn to scale. In the drawings:

fig. 1 shows a schematic cross-sectional view of a multilayer-structured adhesive tape according to the present invention.

Fig. 2 shows a schematic cross-sectional view of a multi-layered structure adhesive tape with a release film according to the present invention.

Fig. 3 shows a schematic flow diagram of a method for producing a multilayer-structured adhesive tape according to the present invention.

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, like reference numerals indicate like or similar parts and features. The drawings are only schematic representations of the concepts and principles of embodiments of the present invention, and do not necessarily show the specific dimensions and proportions of the various embodiments of the invention. Certain features that are part of a particular figure may be used in an exaggerated manner to illustrate relevant details or structures of embodiments of the present invention.

In the description of the embodiments of the present invention, the directional terms used in connection with "up", "down", "left" and "right" are used in the description of the upper, lower, left and right positions of the views shown in the drawings. In practical applications, the positional relationships of "up", "down", "left" and "right" used herein may be defined according to practical situations, and these relationships may be reversed.

The performance indicators described herein as "optical clarity", "haze", "peel force", "surface resistance", and the like, conform to the general definitions in the art and can be measured by testing techniques commonly used in the art.

Fig. 1 shows a schematic cross-sectional view of a multilayer-structured adhesive tape according to the present invention. According to fig. 1, the multilayer structure tape 1 includes a tape base layer 10 and an antistatic layer 20 and an adhesive layer 30 respectively located on opposite sides of the tape base layer 10. The tape base material layer 10 may be a PET film or any other suitable optical film, and the thickness thereof is usually 50 to 75 μm; the antistatic layer 20 is a coating layer coated by an aqueous solution containing single-wall or double-wall carbon nanotubes; the adhesive layer 30 is for adhering to a surface of an electronic device, such as a surface of an OLED liquid crystal display.

The antistatic layer 20 comprises single-walled or double-walled carbon nanotubes. The single-wall or double-wall structure avoids the darker color of the multi-wall carbon nanotubes from adversely affecting the color, transparency, and other optical properties of the tape. By way of example and not limitation, single-walled carbon nanotubes may be produced using JCST-75-1.5-20, manufactured by Nanjing GmbH nanotechnology, inc., and having an average length of about 75nm and an average diameter of about 1.5nm; the double-walled carbon nanotube may be JCST-60-3-50 manufactured by Nanjing Ginko nanotechnology Co., ltd., and has an average length of about 60nm and an average diameter of about 3nm. A water-soluble or water-dispersible binder (binder), such as DSM986 binder manufactured by DSM corporation, is further included in the antistatic layer 20 for uniformly dispersing the carbon nanotubes in an aqueous solution and uniformly coating the carbon nanotubes during the process of forming the antistatic layer 20. Commercially available premixes of carbon nanotubes and binders, such as JCGMT-999-11-30-COOH, manufactured by Nanjing Ginko nanotechnology, inc., can also be used directly. The thickness of the antistatic layer 20 is preferably less than 80nm to ensure good optical performance. The specific preparation process will be described in detail hereinafter.

The adhesive layer 30 is preferably a low viscosity adhesive, such as a polyurethane adhesive, so as not to damage the OLED liquid crystal display and the multi-layer structure tape 1 during the process of peeling the multi-layer structure tape 1 from the OLED liquid crystal display. The preferred viscosity is a peel force of less than 15g/inch. Commercially available polyurethane adhesives include, for example, CYABINE SP205 manufactured by Toyo ink corporation and PA-67-2 manufactured by New chemical corporation. The polyurethane adhesive is mixed with a suitable crosslinking agent and an organic solvent so as to be coated on one side of the tape base material layer 10. An antistatic ionic liquid, such as HQ115 from 3M company, is also included in the adhesive layer 30 to provide some antistatic function to the adhesive layer 30. Optionally, a plasticizer or the like for further reducing the viscosity may also be included in the adhesive layer 30.

As shown in fig. 2, in other embodiments, the outer surface of the adhesive layer 30 may also be covered with a peelable release film 40 to protect the adhesive layer 30 before use. The release film 40 can also be made of PET film.

Next, a method for producing the multilayer-structured adhesive tape 1 will be described in detail with reference to fig. 3.

In step S1, a binder solution is prepared. In the present embodiment, a polyurethane binder, an organic solvent (such as methyl ethyl ketone), and an antistatic ionic liquid are mixed in an appropriate ratio. Alternatively, a suitable plasticizer may be added according to the desired target viscosity. Wherein the viscosity is such that the peel force is less than 15g/inch.

In step S2, a single-wall or double-wall carbon nanotube aqueous dispersion solution is prepared. Single-wall or double-wall carbon nanotubes and a water-soluble or water-dispersible binder are mixed and dispersed in deionized water in a suitable ratio to form an aqueous dispersion solution, the mass concentration of which is, for example, about 1%. An appropriate amount of carboxyl or similar functional groups may be added to the aqueous dispersion solution of carbon nanotubes to improve the hydrophilicity of the carbon nanotubes, so that the carbon nanotubes are more easily uniformly dispersed in the aqueous solution.

In step S3, an antistatic layer 20 is formed from the single-walled or double-walled carbon nanotube aqueous dispersion solution prepared in step S2. The antistatic layer 20 is formed by uniformly coating the carbon nanotube aqueous dispersion solution on one side of the tape base layer 10 using a mesh roller, and drying the carbon nanotube aqueous dispersion solution by natural air drying or baking in an oven. The thickness of the coating after drying is calculated from the weight and mass concentration of the applied aqueous dispersion of carbon nanotubes, and preferably less than 80nm to ensure good optical properties. The temperature and time of natural air drying or oven drying depend on the weight and mass concentration of the coated aqueous dispersion solution of carbon nanotubes. For example, in the present embodiment, the coating layer is heated in an oven at a temperature of 100 ℃ for 5 minutes to form the antistatic layer 20.

In step S4, the adhesive layer 30 is formed from the adhesive solution prepared in step S1. The urethane adhesive solution is uniformly applied to the other side of the tape base material layer 10 to form a coating layer having a thickness of about 20 to 25 μm, and the coated tape base material layer 10 is heated in an oven to dry the urethane adhesive solution and cure the urethane adhesive. The time and temperature of drying and curing depends on the composition of the polyurethane adhesive solution and the coating thickness, for example, in this embodiment the adhesive layer 30 is heated in an oven at a temperature of 100 ℃ for 10 minutes.

Optionally, in step S5, a PET release film 40 is laminated on the formed adhesive layer 30. The thickness of the release film 40 may be generally about 50 μm.

In step S6, post-curing treatment is performed. In the present embodiment, the multilayer-structured adhesive tape 1 formed by the above steps is placed in an oven at 60 ℃ for two days to complete the post-curing of the adhesive layer 30. The time and temperature of the post-curing treatment can be adaptively adjusted according to the composition and thickness of the adhesive layer 30.

The order of some of the above-described steps may be interchanged without explicitly indicating or implying any order of operation. For example, it is apparent that the steps S1 and S2 of preparing the binder solution or the carbon nanotube aqueous dispersion solution in advance may be performed in an interchangeable order or simultaneously, and the steps S3 and S4 of forming the antistatic layer 20 and the binder layer 30 by coating and drying, respectively, may be performed in an interchangeable order.

By the above preparation method, the multilayered structure tape 1 having excellent optical transparency, excellent and stable antistatic properties, and low viscosity can be formed. The use of single-walled or double-walled carbon nanotubes rather than multi-walled carbon nanotubes can provide the antistatic layer 20 with a clear, blackish appearance and excellent optical transparency and haze, for example, optical transparency can be up to 86% or more and haze can be less than 4.5%. Meanwhile, the antistatic layer 20 containing single-wall or double-wall carbon nanotubes can achieve a surface resistance of the order of 10^6ohm/sq and can maintain a surface resistance of the order of 10^6ohm/sq after long-term exposure to ultraviolet rays, which means that the antistatic layer 20 has excellent antistatic properties that are not easily deteriorated. The carbon nanotubes are dispersed in the aqueous solution by the water-soluble or water-dispersible binder to form a uniform aqueous dispersion solution of the carbon nanotubes, thereby facilitating the uniform coating of the carbon nanotubes on the tape base material layer 10. The adhesive layer 30 having a peel force of less than 15g/inch formed using a low viscosity adhesive can protect the OLED liquid crystal display and the multilayer structure tape 1 from damage during peeling.

Here, exemplary embodiments of the multilayered structure tape having a carbon nanotube antistatic layer and the method for preparing the same according to the present invention have been described in detail, but it should be understood that the present invention is not limited to the specific embodiments described and illustrated in detail above. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention. All such variations and modifications are intended to be within the scope of the present invention. Moreover, all the components described herein can be replaced by other technically equivalent components.

Claims

1. A multilayer structure adhesive tape comprises an adhesive tape base material layer, an antistatic layer and an adhesive layer, wherein the antistatic layer and the adhesive layer are positioned on two opposite sides of the adhesive tape base material layer, and the antistatic layer contains single-wall or double-wall carbon nano tubes.

2. The tape of claim 1, wherein the antistatic layer is formed by coating an aqueous dispersion solution comprising the single-or double-walled carbon nanotubes and a water-soluble or water-dispersible binder on one side of the tape base layer and drying.

3. The multilayer structure tape of claim 1, wherein the antistatic layer has a thickness of less than 80nm.

4. The multilayer structured tape of claim 1 wherein the adhesive layer comprises a polyurethane adhesive.

5. The multilayer structured tape of claim 4 wherein the peel force of the adhesive layer is less than 15g/inch.

6. The multilayer structure tape of claim 4 wherein the adhesive layer comprises a plasticizer.

7. The multilayer structure tape of claim 1 further comprising a release film overlying the adhesive layer.

8. A method of making a multilayer construction tape comprising a tape substrate layer, the method comprising:

preparing a binder solution;

preparing an aqueous dispersion solution comprising single-walled or double-walled carbon nanotubes;

coating the aqueous dispersion solution on one side of the adhesive tape base material layer and drying to form an antistatic layer;

coating the adhesive solution on the other side of the adhesive tape base material layer, and drying and curing to form an adhesive layer; and

and carrying out post-curing treatment on the adhesive layer.

9. The method of claim 8, wherein the aqueous dispersion solution comprises a water-soluble or water-dispersible binder.

10. The method of claim 8, wherein the antistatic layer is formed to a thickness of less than 80nm.

11. The method of claim 8, wherein the adhesive layer is formed using a polyurethane adhesive.

12. The method of claim 11, wherein the adhesive layer is formed to have a peel force of less than 15g/inch.

13. The method of claim 8, further comprising laminating a release film on the adhesive layer.