WO2018116130A1

WO2018116130A1 - Adhesive layer

Info

Publication number: WO2018116130A1
Application number: PCT/IB2017/058064
Authority: WO
Inventors: Xuan WU
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2016-12-22
Filing date: 2017-12-18
Publication date: 2018-06-28
Anticipated expiration: 2019-06-22
Also published as: CN206486463U

Abstract

An adhesive tape, comprising a base layer and a first adhesive layer located on one side of the base layer. The first adhesive layer comprises a first bonding region with a first binding property and a second bonding region with a second binding property, wherein the first binding property is different from the second binding property, the first bonding region is a hot melt adhesive region, and the second bonding region is a pressure sensitive adhesive region. Thus, bonding properties of different bonding regions can be taken full advantage of, and sufficiently high bonding strength is ensured while the thickness of the adhesive tape is significantly reduced.

Description

ADHESIVE LAYER

TECHNICAL FIELD

The present application relates to an adhesive tape, and more particularly to a double faced adhesive tape used in electronic devices.

BACKGROUND

In recent years, with the development in the manufacturing industry, many products, especially electronic products such as hand-held mobile devices and tablet computers undergo a development trend of making them thinner and lighter. Therfore, manufacturers of these products require that adhesive tapes used therein for bonding components and parts are also made thinner. However, common adhesives, for example, acrylate adhesives, fail to provide sufficient bonding strength when thickness is reduced. Therefore, adhesive tapes used at present fail to satisfy the requirement of making the products thinner and lighter. For double faced adhesive tapes, this problem is more prominent.

Therefore, requirements are elicited for adhesive tapes that are as thin as possible and at the same time can provide sufficient bonding strength.

SUMMARY

Objectives of the present application are two-fold: to provide an adhesive tape that can achieve a good balance between bonding strength and thinness, and to provide a double faced adhesive tape that can achieve a good balance between bonding strength and thinness. The adhesive tape according to the present application can achieve high-strength bonding while the thickness of the adhesive tape is reduced.

According to one aspect of the present application, an adhesive tape is provided, which may comprise a base layer, and a first adhesive layer located on one side of the base layer. The first adhesive layer comprises a first bonding with a first binding property and a second bonding region with a second binding property. The first binding property is different from the second binding property. The first bonding region is a hot melt adhesive region and the second bonding region is a pressure sensitive adhesive region. In one embodiment of the present application, the first bonding region and the second bonding region may be disposed along the base layer into one or more of the following configurations:

a) the first bonding region and the second bonding region are linear-type strip regions, and the first bonding region and the second bonding region are disposed alternately along the base layer in the width or length direction of the adhesive tape;

b) the first bonding region and the second bonding region are curve-type strip regions, and the first bonding region and the second bonding region are disposed alternately along the base layer in the width or length direction of the adhesive tape; and

c) the second bonding region is distributed in the spotted region within the first bonding region, and the lower surface of the spotted region is connected to the base layer.

In one embodiment of the present application, a gap may exist between the second bonding region and the first bonding region.

In one embodiment of the present application, the upper surface of the second bonding region may be flush with the upper surface of the first bonding region.

In one embodiment of the present application, the upper surface of the second bonding region may be higher than the upper surface of the first bonding region.

In one embodiment of the present application, the base layer may be a polyester film layer.

In one embodiment of the present application, the pressure sensitive adhesive region may comprise one or more of: an acrylate pressure sensitive adhesive region, a rubber pressure sensitive adhesive region and an organosilicon pressure sensitive adhesive region.

In one embodiment of the present application, the adhesive tape may further comprise a second adhesive layer located on the other side of the base layer, where the second adhesive layer may have a third binding property.

In one embodiment of the present application, the third binding property may be different from at least one of the first binding property and the second binding property.

In one embodiment of the present application, the second adhesive layer may comprise one or more of: an acrylate pressure sensitive adhesive layer, a rubber pressure sensitive adhesive layer and an organosilicon pressure sensitive adhesive layer. In one embodiment of the present application, the first adhesive layer may have a thickness equal to or less than 50 μπι, preferably equal to or less than 25 μπι, or even as low as 14 μπι.

In one embodiment of the present application, the first bonding region may have an area accounting for 30% to 70% based on the total area of the first adhesive layer.

In one embodiment of the present application, the first bonding region may have an area accounting for 40% to 60% based on the total area of the first adhesive layer. In some embodiments, the first bonding region may have an area equal to that of the second bonding region.

In one embodiment of the present application, the first bonding region may have a width that is 0.7 to 1.3 times that of the second bonding region.

In one embodiment of the present application, the first bonding region and the second bonding region may each have a width between 1 mm and 20 mm, for example, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm or 20 mm, or any size of a non-integer between the above integers. In particular, in some embodiments, the first bonding region and the second bonding region may each have a width between 1 mm and 4 mm or between 2 mm and 3 mm.

In one embodiment of the present application, the first adhesive layer is configured to adhere to a plastic or metal surface, and/or the second adhesive layer is configured to adhere to one or more of: a surface of an organosilicon material, a surface of a fluorine-containing material, and a surface of a nylon material.

According to exemplary embodiments of the present application, because first bonding regions and second bonding regions disposed alternately are employed in an adhesive layer of the adhesive tape, a balance can be formed between bonding properties of different bonding regions, different bonding properties can be taken full advantage of, and ,for example, a temporary or permanent bonding effect can be achieved.

In particular, in the adhesive tape according to exemplary embodiments of the present application, hot melt adhesive regions and pressure sensitive adhesive regions are disposed alternately in the adhesive layer, so that the problem of insufficient adhesion strength due to reduction in thickness of the pressure sensitive adhesive layer is overcome by high bonding strength of the hot melt adhesive; and at the same time, when the adhesive tape is mold-cut, a temporary bonding effect is provided by the stickiness of the pressure sensitive adhesive region and the mold-cutting problem of the hot melt adhesive is solved. Therefore, high-strength bonding is achieved while the thickness of the adhesive tape is significantly reduced.

The double faced adhesive tape according to exemplary embodiments of the present application can be applied to bond, for example, a silicone rubber surface to a plastic or metal surface.

Moreover, according to exemplary embodiments of the present application, by substituting a rubber pressure sensitive adhesive region or an organosilicon pressure sensitive adhesive region for an acrylate pressure sensitive adhesive region, the obtained double faced adhesive tape can be used to bond a silicone rubber surface to a surface of other materials.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic stereogram showing a structure of a double faced adhesive tape according to a first exemplary embodiment of the present application.

FIG. 2 is a schematic stereogram showing a structure of a double faced adhesive tape according to a second exemplary embodiment of the present application.

FIG. 3 is a schematic end view showing a structure of a double faced adhesive tape according to the second exemplary embodiment of the present application.

FIG. 4 is a schematic view showing a production process of a double faced adhesive tape according to exemplary embodiments of the present application.

DETAILED DESCRIPTION

Double faced adhesive tapes can be used in hand-held mobile devices such as cellphones and PDAs to assemble buttons formed from silicone rubber at the bottom to the body of the hand-held mobile device. A double faced adhesive tape commonly used at present comprise a base layer, an organosilicon pressure sensitive adhesive layer disposed on one side of the base layer, and an acrylate pressure sensitive adhesive layer disposed on the other side of the base layer. The organosilicon pressure sensitive adhesive layer of the double faced adhesive tape is bonded to silicone rubber at the bottom of the buttons, and the acrylate pressure sensitive adhesive layer of the double faced adhesive tape is bonded to a plastic or metal surface of the body of the hand-held mobile device. Such double faced adhesive tapes are, for example, double faced adhesive tapes of Models 9119, 4377, and 9731 commercially available from 3M Corporation at present.

In order to ensure firm connection between buttons of the hand-held mobile device with the body, it is required that proper bonding strength is present between the organosilicon pressure sensitive adhesive layer and the acrylate pressure sensitive adhesive layer of the existing double faced adhesive tape, and corresponding surfaces to be bonded. Thus it is required that the organosilicon pressure sensitive adhesive layer and the acrylate pressure sensitive adhesive layer have a certain thickness. However, in recent years, due to the development trend of making hand-held mobile devices thinner and lighter, hand-held mobile devices are required to be thinner and thinner. Therefore, hand-held mobile devices are also increasingly sensitive to the thickness of the adhesive tape used therein. For example, currently manufacturers of hand-held mobile devices expect the adhesive tapes to have a thickness equal to or less than 150 μπι. Regarding certain light and thin products, there still exists a trend of expecting further thinning of the adhesive tapes. However, at a reduced thickness of 50 μπι, a conventional acrylate pressure sensitive adhesive will fail to provide sufficient cohesive force on a plastic or metal surface. Thus the double faced adhesive tapes used at present fail to provide sufficient bonding strength at such a thinness. In order to satisfy the requirement for lighter and thinner products, the present application presents a novel adhesive tape. A good balance is achieved between bonding strength and thickness of the adhesive tape, thus high-strength bonding can be achieved while the thickness of the adhesive tape is reduced.

The present application will be described below in detail referring to accompanying drawings and based on exemplary embodiments. It is to be understood by those of skill in the art that, the accompanying drawings referred in the following description are provided for the convenience of understanding conceptions of the present application and are not necessarily drawn strictly to scale.

As an example, an embodiment of the present application presents a novel double faced adhesive tape 1. It can be understood by those of skill in the art that, the design conceptions of the present application are equally applicable to single faced adhesive tapes. FIG. 1 is a schematic stereogram showing a structure of the double faced adhesive tape 1 according to a first exemplary embodiment of the present application. Referring to FIG. 1, the double faced adhesive tape 1 generally comprises: a base layer 11, a first adhesive layer 12 located on one side of the base layer 11, and a second adhesive layer 13 located on the other side of the base layer 11.

It can be understood by those of skill in the art that, a single faced adhesive tape can comprise only a base layer and an adhesive layer located on one side of the base layer. In the embodiment of the present application, the base layer 11 may be a polyester film layer. It should be understood that the base layer 11 is not limited to a polyester film, but it can be constituted by a thin film having substantially the same properties as the polyester film to satisfy the requirement for the support strength of the adhesive layer in particular applications.

According to the embodiment of the present application, at least one of the first adhesive layer 12 and the second adhesive layer 13 may be an adhesive layer comprising multiple bonding regions having different bonding properties.

Referring to FIG. 1, in the exemplary embodiment, the first adhesive layer 12 may comprise one or more first bonding regions 121 with a first binding property, and one or more second bonding regions 122 with a second binding property, wherein the first binding property is different from the second binding property.

In the exemplary embodiment, the first bonding region 121 and the second bonding region 122 are disposed alternately along the base layer 11, to allow each second bonding region 122 to locate between two adjacent first bonding regions 121.

In the exemplary embodiment, the first bonding region 121 and the second bonding region 122 are disposed as linear-type strip regions.

It should be understood that, the first bonding region 121 and the second bonding region 122 in the first adhesive layer 12 are limited to linear-type strip regions. In the embodiment of the present application, the first bonding region and the second bonding region in the first adhesive layer 12 may be curve-type strip regions or any irregular-shaped regions with shapes matching each other disposed alternately along the base layer 11. In other words, in the embodiment of the present application, the adjacent first and second bonding regions have complementary shapes in a plane parallel to the base layer 11. In the exemplary embodiment, the first bonding region 121 and the second bonding region 122 in the first adhesive layer 12 are extended in the length direction of the double faced adhesive tape 1 and disposed alternately in the width direction of the double faced adhesive tape 1 along the base layer 11. It should be understood that, in the embodiment of the present application, the first bonding region and the second bonding region may be extended in the width direction of the double faced adhesive tape 1 and disposed alternately in the length direction of the double faced adhesive tape 1 along the base layer 11.

In the exemplary embodiment shown in FIG. 1, the first bonding region 121 and the second bonding region 122 in the first adhesive layer 12 are shown to have the same width w and the same thickness h. In other words, the first bonding region 121 and the second bonding region 122 with the same width can be disposed alternately in the width or length direction of the double faced adhesive tape 1 along the base layer 11, and the upper surface of the second bonding region 122 is flush with the upper surface of the first bonding region 121.

In the embodiment of the present application, the second bonding region may be a spotted region uniformly or non-uniformly distributed in the first bonding region. In some embodiments, the spotted region of the second bonding region is formed with its lower surface connected to the base layer 11 and its upper surface flush with the upper surface of the first bonding region. In some embodiments, the spotted region of the second bonding region may be formed with its upper surface higher than the upper surface of the first bonding region.

In the exemplary embodiment, the first bonding region 121 of the first adhesive layer 12 may be a hot melt adhesive region, and the second bonding region 122 may be a pressure sensitive adhesive region such as an acrylate pressure sensitive adhesive region, a rubber pressure sensitive adhesive region, or an organosilicon pressure sensitive adhesive region. According to the exemplary embodiment of the present application, the first bonding region 121 is constituted by a hot melt adhesive.

As stated above, in the face of a technical problem of reducing the thickness of a double faced adhesive tape, those of skill in the art will frequently expect to reduce the thickness of a double faced adhesive tape by reducing the thickness of an acrylate pressure sensitive adhesive layer, a rubber pressure sensitive adhesive layer or an organosilicon pressure sensitive adhesive layer and the like of, for example, a conventional double faced adhesive tape. However, the reduction in thickness of the acrylate pressure sensitive adhesive layer, the rubber pressure sensitive adhesive layer or the organosilicon pressure sensitive adhesive layer and the like will result in insufficient binding force.

With regard to this, provided herein is a technical solution in which a hot melt adhesive region constituted by a hot melt adhesive and a pressure sensitive adhesive region constituted by a conventional acrylate pressure sensitive adhesive, a rubber pressure sensitive adhesive or an organosilicon pressure sensitive adhesive are disposed alternately in the adhesive layer of an adhesive tape.

A hot melt adhesive is a meltable solid polymer, which is a solid at normal temperature and becomes a flowable liquid with a certain viscosity when heated and molten to a certain temperature. After coating and wetting a surface to be bonded and after being pressed and cooled, it can bond to the surface to be bonded in several seconds. A hot melt adhesive has advantages such as a high bonding strength and a high curing rate. However, because the hot melt adhesive is a solid at normal temperature, it cannot provide sufficient viscosity, and a problem of localization difficulty will arise in the mold-cutting process. Moreover, because the hot melt adhesive is highly influenced by the temperature, problems such as wiredrawing and backflowing of the adhesive also exist in the pre-attachment process. Therefore, currently in double faced adhesive tapes employed in, for example, hand-held mobile devices, if the adhesive layer of the adhesive tape is constituted by a hot melt adhesive alone, the effect thereof is not ideal.

In the double faced adhesive tape 1 according to the exemplary embodiment of the present application, by means of alternately disposing the hot melt adhesive regions and the pressure sensitive adhesive regions along the base layer 11, the problem of insufficient binding force due to reduction in the thickness of the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region is overcome by the high bonding strength of the hot melt adhesive constituting the hot melt adhesive region. At the same time, by means of disposing the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region with a reduced thickness, a proper binding force for temporary localization is provided and the problems of wiredrawing and backflowing of the adhesive and the like that may exist in the pre-attachment process required in the hot melt adhesive region. Therefore, as compared with a double faced adhesive tape in the prior art in which a first adhesive layer is wholly formed by an acrylate pressure sensitive adhesive, a rubber pressure sensitive adhesive or an organosilicon pressure sensitive adhesive, the same or even greater binding force can be obtained while the first adhesive layer 12 of the double faced adhesive tape 1 is significantly reduced in thickness. Thus the thickness of the double faced adhesive tape 1 is significantly reduced. For example, the first adhesive layer 12 of the double faced adhesive tape 1 according to the embodiment of the present application can be reduced to a thickness equal to or less than 50 μπι. In further preferred embodiments, the first adhesive layer 12 can be reduced to a thickness equal to or less than 25 μπι, or even as low as 14 μπι.

In the exemplary embodiment, multiple strip hot melt adhesive regions and multiple strip acrylate pressure sensitive adhesive regions may be disposed alternately along the base layer 11, where each strip acrylate pressure sensitive adhesive region is disposed between two adjacent strip hot melt adhesive regions, and thus an adhesive layer for bonding to a plastic or metal surface is formed.

In the exemplary embodiment, the first adhesive layer 12 may be constituted by a hot melt adhesive region as the first bonding region 121 and a rubber pressure sensitive adhesive region as the second bonding region 122 disposed alternately along the base layer 11.

Moreover, in the exemplary embodiment, the first adhesive layer 12 may be constituted by a hot melt adhesive region as the first bonding region 121 and an organosilicon pressure sensitive adhesive region as the second bonding region 122 disposed alternately along the base layer 11.

In the exemplary embodiment, the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region may be a spotted region uniformly or non-uniformly distributed in the hot melt adhesive region, wherein the lower surface of the spotted region is connected to the base layer 11.

In the embodiment of the present application, the first bonding region 121 may have an area accounting for 30% to 70% based on the total area of the first adhesive layer 12.

In the exemplary embodiment, the bonding strength of the first adhesive layer will increase with increase in the area of the hot melt adhesive region as the first bonding region 121. However, in consideration of the mold-cutting problem with the hot melt adhesive and ensuring a sufficient temporary binding force, preferably the hot melt adhesive region as the first bonding region 121 may have an area accounting for 30% to 70% based on the total area of the first adhesive layer 12. In some embodiments, the hot melt adhesive region as the first bonding region 121 may have an area accounting for 40% to 60% based on the total area of the first adhesive layer 12. In some embodiments, the hot melt adhesive region as the first bonding region 121 may have an area equal to that of the pressure sensitive adhesive region as the second bonding region 122.

In the embodiment where the hot melt adhesive region and the pressure sensitive adhesive regions such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region are disposed as alternant strip regions, the hot melt adhesive region as the first bonding region 121 may have a width 0.7 to 1.3 times that of the pressure sensitive adhesive region as the second bonding region 122.

In the embodiment of the present application, the first bonding region 121 and the second bonding region 122 in the first adhesive layer 12 of the double faced adhesive tape 1 may each have a width between 1 mm and 20 mm. As required in particular applications, the first bonding region 121 and the second bonding region 122 may each have a width between 1 mm and 40 mm and preferably between 2 mm and 3 mm.

It should be understood that, the first adhesive layer 12 is not limited to the inclusion of only two bonding regions with different binding properties. In the embodiment of the present application, the first adhesive layer 12 may further comprise one or more other bonding regions with a binding property different from the first binding property and the second binding property, and the one or more other bonding regions are disposed alternately with the first bonding region 121 and the second bonding region 122 along the base layer 11, to satisfy various application requirements for different bonding strength.

In the embodiment of the present application, the second adhesive layer 13 of the double faced adhesive tape 1 may have a third binding property different from at least one of: the first binding property of the first bonding region 121 and the second binding property of the second bonding region 122 of the first adhesive layer 12. The second adhesive layer 13 may be reduced to a thickness equal to or less than 50 μπι. In further preferred embodiments, the second adhesive layer 13 may be reduced to a thickness equal to or less than 25 μηι. Therefore, the minimum thickness of the whole double faced adhesive tape can be controlled at about 50 μιη.

In the exemplary embodiment, the second adhesive layer 13 of the double faced adhesive tape 1 may be an organosilicon pressure sensitive adhesive layer, configured to bond to a low-energy surface disposed at the bottom of buttons of, for example, hand-held mobile devices. In the present application, the low-energy surface refers to a surface with low surface energy and low viscosity, made of a material such as an organosilicon material, a fluorine-containing material and a nylon material.

In the exemplary embodiment, the organosilicon pressure sensitive adhesive layer as the second adhesive layer 13 is configured to bond to a surface made of silicone rubber at the bottom of buttons in the hand-held mobile devices.

It should be understood that, the second adhesive layer 13 of the double faced adhesive tape 1 is not limited to an organosilicon pressure sensitive adhesive layer, but it may be an adhesive layer designed to have other bonding properties as required in practical applications.

In addition, in the embodiment of the present application, the second adhesive layer 13 of the double faced adhesive tape 1 may be alternatively an adhesive layer including multiple bonding regions with different bonding properties, to enable the double faced adhesive tape 1 according to the present application to be used between surfaces with different material properties, for example, between a surface of a plastic material and a surface of a metal material, to perform bonding.

In the embodiment of the present application, the second adhesive layer 12 may comprise one or more of: an acrylate pressure sensitive adhesive layer, a rubber pressure sensitive adhesive layer and an organosilicon pressure sensitive adhesive layer.

In the embodiment of the present application, the second adhesive layer 13 of the double faced adhesive tape 1 may also comprise a first bonding region with a first binding property and a second bonding region with a second binding property. In particular, the second adhesive layer 13 of the double faced adhesive tape 1 may comprise hot melt adhesive regions and pressure sensitive adhesive regions such as acrylate pressure sensitive adhesive regions, rubber pressure sensitive adhesive regions or organosilicon pressure sensitive adhesive regions disposed alternately in the width or length direction of the double faced adhesive tape 1 along the base layer 11. In this case, the total thickness of the double faced adhesive tape 1 can be further reduced, thereby satisfying the increasingly stricter requirement for further reduction in the thickness of the double faced adhesive tape. The double faced adhesive tape 1 obtained thereby can be used between, for example, a plastic surface and a metal surface, between a plastic surface and a plastic surface, and between a metal surface and a metal surface, to perform bonding.

Next, a second exemplary embodiment according to the present application will be explained referring to FIG. 2 and FIG. 3. FIG. 2 is a schematic stereogram showing a structure of a double faced adhesive tape 10 according to a second exemplary embodiment of the present application. FIG. 3 is a schematic end view showing a structure of a double faced adhesive tape 10 according to the second exemplary embodiment of the present application. In both FIG. 2 and FIG. 3, the same reference numerals are employed to denote the same components in FIG. 1, therefore a detailed description thereof is omitted.

Referring to FIG. 2 and FIG. 3, the double faced adhesive tape 10 generally comprises: a base layer 11, a first adhesive layer 120 located on one side of the base layer 11, and a second adhesive layer 13 located on the other side of the base layer 11.

In the exemplary embodiment, the first adhesive layer 120 of the double faced adhesive tape 10 may comprise one or more first bonding regions 1210 with a first binding property and one or more second bonding regions 1220 with a second binding property, wherein the first binding property is different from the second binding property.

As is different from the first exemplary embodiment shown in FIG. 1, in the first adhesive layer 120 of the double faced adhesive tape 10 of the second exemplary embodiment shown in FIG. 2 and FIG. 3, a gap g is present between the first bonding region 1210 and the second bonding region 1220 disposed alternately along the base layer 11. In the exemplary embodiment as shown, the first bonding region 1210 in the first adhesive layer 120 has a thickness of hi, and the second bonding region 1220 has a thickness of h2. In addition, the first bonding region 1210 has a width of wl, and the second bonding region 1220 has a width of w2.

According to the embodiment of the present application, the thickness hi may be different from the thickness h2.

As an example, the thickness hi of the hot melt adhesive region as the first bonding region 1210 is less than the thickness h2 of the pressure sensitive adhesive region as the second bonding region 1220. In other words, the upper surface of the second bonding region 1220 is higher than the upper surface of the first bonding region 1210.

It should be understood that, in some embodiments, the thickness hi may be equal to the thickness h2.

In the embodiment of the present application, the width wl of the first bonding region 1210 in the first adhesive layer 120 may be different from the width w2 of the second bonding region 1220. It should be understood that, in some embodiments, the width wl may be equal to the width w2.

As an example, the first bonding region 1210 of the first adhesive layer 120 may be a hot melt adhesive region, and the second bonding region 1220 may be a pressure sensitive adhesive region such as an acrylate pressure sensitive adhesive region, a rubber pressure sensitive adhesive region or an organosilicon pressure sensitive adhesive region. The first bonding region 1210 may be constituted by a hot melt adhesive.

In the exemplary embodiment, similarly to the first exemplary embodiment, the hot melt adhesive region as the first bonding region 1210 may have a width 0.7 to 1.3 times that of the pressure sensitive adhesive region as the second bonding region 1220.

In the exemplary embodiment, the hot melt adhesive region as the first bonding region 1210 may have an area accounting for 30% to 70% based on the total area of the first adhesive layer 120. In some embodiments, the hot melt adhesive region as the first bonding region 1210 may have an area accounting for 40% to 60% based on the total area of the first adhesive layer 120. In some embodiments, the hot melt adhesive region as the first bonding region 1210 may have an area equal to that of the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region as the second bonding region 1220.

According to the embodiment of the present application, a gap g may be present between the hot melt adhesive region as the first bonding region 1210 and the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region as the second bonding region 1220.

The arrangement of the gap g between the bonding regions allows, for example, the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region as the second bonding region 1220 to deform moderately in the process of binding to a surface to be bonded, thereby to increase the bonding surface so as to enhance the binding force and further reduce thickness of the adhesive tape after bonding.

Referring to FIG. 3, the surface to be bonded is denoted by a dashed line P. In the process where the double faced adhesive tape 10 is bonded to the surface to be bonded P, when pressure is applied from the side of the second adhesive layer 13 of the double faced adhesive tape 10 toward the first adhesive layer 120 to allow the first adhesive layer 120 to bond to the surface to be bonded P, because the upper surface of the second bonding region 1220 is higher than the upper surface of the first bonding region 1210, the second bonding region 1220 will contact the surface to be bonded P prior to the first bonding region 1210. Then, pressure is further applied to the double faced adhesive tape 10 until the first bonding region 1210 such as the hot melt adhesive region contacts the surface to be bonded P. The second bonding region 1220 will get further closer to the surface to be bonded P under the action of the pressure and thus will deform. In FIG. 3, the deformation by force of the second bonding region 1220 is shown schematically with broken curves. The lateral deformation of the second bonding region 1220 will increase the contact area between the second bonding region 1220 and the surface to be bonded P, thereby increasing the bonding strength correspondingly. At the same time, the gap g disposed between the bonding regions will accommodate the lateral deformation of the second bonding region 1220 to allow the double faced adhesive tape 10 to be further pushed toward the surface to be bonded P. When the first bonding region 1210 such as the hot melt adhesive region contacts the surface to be bonded P, the first adhesive layer 120 that has been bonded will have a thickness substantially of hi . In other words, the gap g is disposed such that the thickness of the adhesive tape after bonding can be further reduced.

Next, the usage and operation of the double faced adhesive tape according to the present application will be explained through an example.

When the double faced adhesive tape 1 or 10 according to the exemplary embodiment of the present application is used for bonding, the double faced adhesive tape is firstly mold-cut according to the application requirement for the double faced adhesive tape, to allow the double faced adhesive tape to have a shape corresponding to the bonding surface of a member to be bonded. In the mold-cutting process, a temporary bonding effect is provided by, for example, the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region as the second bonding region, thereby achieving good localization. At the same time, the pressure sensitive adhesive region is disposed such that problems with the hot melt adhesive region such as wiredrawing and backflowing of the adhesive that may exist in the pre-attachment process are more effective. Subsequently, the second adhesive layer 13 such as the organosilicon pressure sensitive adhesive layer of the mold-cut double faced adhesive tape 1 or 10 is bonded to, for example, the bottom formed by silicone rubber, of buttons of the hand-held mobile devices.

Subsequently, the buttons with the double faced adhesive tape 1 or 10 stuck thereto are aligned with and pressured against the surface to be bonded of the body of the hand-held mobile device, to allow the first adhesive layer 12 of the double faced adhesive tape 1 or the first adhesive layer 120 of the double faced adhesive tape 10 to contact the plastic or metal surface to be bonded of the body of the hand-held mobile devices. Therefore, the buttons are temporarily fixed on the surface to be bonded, through the weak adhesiveness of, for example, the pressure sensitive adhesive region such as the acrylate pressure sensitive adhesive region, the rubber pressure sensitive adhesive region or the organosilicon pressure sensitive adhesive region as the second bonding region in the first adhesive layer.

Particularly, when a gap g is disposed between the first bonding region 1210 and the second bonding region 1220 of the first adhesive layer 120 of the double faced adhesive tape 10, the second bonding region 1220 deforms by force and thus fills in a portion of the gap g, thereby increasing the contact area between the second bonding region 1220 and the surface to be bonded P and thereby ensuring temporary fixture of buttons on the surface to be bonded P through the binding force between the second bonding region 1220 and the surface to be bonded P.

Subsequently, the bonded surface is heated, to melt the hot melt adhesive in the hot melt adhesive region as the first bonding region and wet the bonded surface. Particularly, when a gap g is disposed between the first bonding region 1210 and the second bonding region 1220 of the first adhesive layer 120 of the double faced adhesive tape 10, the hot melt adhesive that has been molten will flow to a portion of the gap g which is not filled due to deformation of the second bonding region 1220, to ensure high-quality bonding. Then, the overall structure of the hand-held mobile device is cooled, thereby achieving high-strength bonding between the silicone rubber surface at the bottom of the buttons of the hand-held mobile device and the plastic or metal surface to be bonded of the body of the hand-held mobile device by cooling and curing the hot melt adhesive.

An exemplary production process of the double faced adhesive tape 1 according to the present application will be explained below referring to FIG. 4. It is to be understood by those of skill in the art that, various parameters described hereinafter, for example, time, temperature and size, are all exemplary, and these parameters can be set reasonably as required.

According to the exemplary embodiments of the present application, a backing material can be coated onto a polyester film with a thickness of 0.0005 in (i.e., 12.5 μπι) as the base layer 11 of the double faced adhesive tape 1 that has been subjected to corona treatment, with a #3 Mayer stick. The polyester film coated with the backing material is dried in the atmosphere to remove the solvent, but not subjected to curing treatment.

Subsequently, an organosilicon pressure sensitive adhesive is coated onto the polyester film coated with the backing material, and the thickness of the organosilicon pressure sensitive adhesive is controlled at 25 μπι. The polyester film coated with the organosilicon pressure sensitive adhesive is dried for 2 min at 80°C, and then cured for 5 min at 150°C, so as to form an organosilicon pressure sensitive adhesive layer as the second adhesive layer 13 on the polyester film. Subsequently, a release film (not shown) is laminated onto the organosilicon pressure sensitive adhesive layer, to provide isolation when, for example, the double faced adhesive tape 1 is wound up. The release film is a commercially known available product, therefore a detailed description thereof is omitted herein.

Then, as shown in FIG. 4, on the other side opposite to one side coated with the organosilicon pressure sensitive adhesive of the polyester film as the base layer 11 of the double faced adhesive tape 1, the hot melt adhesive is directly coated, by an adhesive tape coating mold 161, onto a region on the polyester film designed for the first bonding region 121 of the first adhesive layer 12, and the thickness of the hot melt adhesive is controlled at 14 μπι. Subsequently, the structure coated with the strip hot melt adhesive is dried for 2 min at 80°C, and then dried for 2 min at 120°C, thereby forming the first bonding region 121 of the first adhesive layer 12 of the double faced adhesive tape 1 according to the embodiments of the present application. It should be understood that, the adhesive tape coating mold 161 can be set according to the design requirement for the double faced adhesive tape 1, so as to coat, for example, multiple tapes of hot melt adhesive spaced apart on the polyester film at the same time. The spacing between two adjacent hot melt adhesive tapes is equal to the width of the second bonding region 122 of the first adhesive layer 12.

Subsequently, an acrylate adhesive is coated by the adhesive tape coating mold 162 between the adjacent strip hot melt adhesive on the polyester film that has subjected to drying treatment, and the thickness of the acrylate adhesive is controlled at 14 μπι. It should be understood that, the adhesive tape coating mold 162 can be set according to the design requirement for the double faced adhesive tape 1, so as to coat, for example, multiple tapes of acrylate adhesive spaced apart on the polyester film at the same time. Subsequently, the structure coated with the acrylate adhesive is dried for 2 min at 80°C, and then dried for 2 min at 130°C, thereby to form the second bonding region 122 of the first adhesive layer 12 of the double faced adhesive tape 1 according to embodiments of the present application, and thus form the first adhesive layer 12 according to the present application comprising multiple first bonding regions 121 with the first binding property and multiple second bonding regions 122 with the second binding property disposed alternately. Subsequently, a release film (not shown) is laminated onto the first adhesive layer 12, thereby to achieve the production of the double faced adhesive tape 1 according to the exemplary embodiments of the present application.

It should be understood that, regarding the double faced adhesive tape 10 according to the second embodiment of the present application, the production process thereof is the same as that of the double faced adhesive tape 1, except that when the acrylate adhesive is coated, a gap g between the acrylate adhesive and an adjacent strip hot melt adhesives is required to be set aside, and/or the thickness of the acrylate adhesive can be controlled slightly greater than that of the hot melt adhesive. The detailed description thereof is omitted herein.

Next, the bonding strength of the double faced adhesive tape 1 according to the exemplary embodiment of the present application will be explained in combination with Table 1.

According to the testing standard ASTM 3330 for peel strength of pressure sensitive adhesive tapes, employing a testing method for 180° peel strength of pressure sensitive adhesive tapes, the bonding strength between a silicone rubber surface and a stainless steel surface as well as between a silicone rubber surface and an epoxy resin surface bonded together with the double faced adhesive tape 1 according to exemplary embodiments of the present application (wherein the base layer 11 (i.e., the polyester film layer) has a thickness of 12.5 μπι, the first adhesive layer 12 (i.e., the adhesive layer with acrylate pressure sensitive adhesive region/hot melt adhesive region disposed alternately) has a thickness of 14 μπι, and the second adhesive layer 13 (i.e., the organosilicon pressure sensitive adhesive layer) has a thickness of 23 μπι) after heated at a temperature condition of 120°C and subjected to a pressure for 10 s, is measured. Results of the measurement are summarized in Table 1 :

Table 1

As can be seen from the results of measurement in Table 1, very high bonding strength is obtained between the silicone rubber surface and the metal surface as well as the plastic surface, by using the double faced adhesive tape 1 reduced in the thickness according to exemplary embodiments of the present application.

The present application is explained above with reference to accompanying drawings and through description of embodiments, but the present application is not limited to the above embodiments. It can be understood by those of skill in the art, modifications and variations can be made without departing from technical ideas of the present application, which modifications and variations are equally comprehended within the protection scope of the present application.

Claims

1. An adhesive tape, comprising:

a base layer, and

a first adhesive layer located on one side of the base layer, wherein

the first adhesive layer comprises a first bonding region with a first binding property and a second bonding region with a second binding property, wherein the first binding property is different from the second binding property, and

the first bonding region is a hot melt adhesive region and the second bonding region is a pressure sensitive adhesive region.

2. The adhesive tape according to claim 1, wherein, the first bonding region and the second bonding region are disposed along the base layer into one or more of the following configurations:

c) the second bonding region is distributed in a spotted region within the first bonding region, and the lower surface of the spotted region is connected to the base layer.

3. The adhesive tape according to claim 1, wherein, a gap exists between the second bonding region and the first bonding region adjacent thereto.

4. The adhesive tape according to claim 1, wherein, the upper surface of the second bonding region is flush with the upper surface of the first bonding region, or

the upper surface of the second bonding region is higher than the upper surface of the first bonding region.

5. The adhesive tape according to claim 1, wherein, the base layer is a polyester film layer.

6. The adhesive tape according to claim 1, wherein, the pressure sensitive adhesive region comprises one or more of: an acrylate pressure sensitive adhesive region, a rubber pressure sensitive adhesive region and an organosilicon pressure sensitive adhesive region.

7. The adhesive tape according to any one of claims 1 to 6, wherein, the adhesive tape further comprises a second adhesive layer located on the other side of the base layer, wherein the second adhesive layer has a third binding property that is different from at least one of the first binding property and the second binding property.

8. The adhesive tape according to claim 7, wherein, the second adhesive layer comprises one or more of: an acrylate pressure sensitive adhesive layer, a rubber pressure sensitive adhesive layer and an organosilicon pressure sensitive adhesive layer.

9. The adhesive tape according to any one of claims 1 to 6, wherein, the first adhesive layer has a thickness equal to or less than 50 μπι.

10. The adhesive tape according to any one of claims 1 to 6, wherein, the first bonding region has an area accounting for 30% to 70% based on the total area of the first adhesive layer, or

the first bonding region has a width 0.7 to 1.3 times that of the second bonding region.

11. The adhesive tape according to any one of claims 1 to 6, wherein, the first bonding region and the second bonding region each have a width between 1 mm and 20 mm.

12. The adhesive tape according to claim 7, wherein, the first adhesive layer is configured to adhere to a plastic or metal surface, and/or the second adhesive layer is configured to adhere to one or more of: a surface of an organosilicon material, a surface of a fluorine-containing material, and a surface of a nylon material.