CN103455191A - Composite film structure and touch panel with same - Google Patents

Abstract

The invention discloses a composite film structure and a touch panel with the composite film structure. The composite film structure includes resistive adhesive layers and capacitive adhesive layers stacked up and down. The touch panel of the present invention includes at least one Conductive layer, at least one composite film and a cover plate, so that the cover plate is adhered to the resistive adhesive layer of the composite film, so that the capacitive adhesive layer of the composite film is bonded to the conductive layer to prevent resistive The acidic glue of the adhesive layer diffuses into the conductive layer to protect the conductive layer from being corroded by the acidic glue; at the same time, the composite film of the present invention can also avoid remaining air bubbles and maintain the optical characteristics of the touch panel.

Description

Composite film structure and touch panel with composite film structure

technical field

The invention relates to a composite film structure and a touch panel with the composite film structure.

Background technique

A touch panel is a device attached to a liquid crystal panel. It uses a finger or a stylus as an operation interface to perform operations such as selecting items, inputting or moving them by light touch. It is an intuitive human-machine interface. In recent years, touch panels have been widely used in consumer electronics products, and have expanded to mainstream 3C electronic products, including mobile phones, GPS, PDAs, tablet computers, e-books, etc., all have a large market, and its future growth is possible expected.

Touch panels can be mainly divided into resistive, capacitive, acoustic, optical and electromagnetic touch panels, and resistive and capacitive touch panels account for 95% of the market.

The structure of the capacitive touch panel can be divided into film-type and glass-type capacitive touch panels. The thin-film capacitive touch panel is made of a polyester (PET) substrate surface treated with ITO (Indium Tin Oxide, indium tin oxide) coating, and then processed into a yellow light process to make a touch sensor (stick two pieces of ITO film or stick a piece of ITO film) and the protective layer (glass/PMMA (polymethyl methacrylate)/PC (polycarbonate)) and TFT-LCD (thin film transistor-liquid crystal display) liquid crystal panel are laminated to form a touch panel module. The glass-type capacitive touch panel is made of a glass substrate after processing, ITO coating, and then a yellow light process to make a touch sensor, and then bond it with a protective layer (glass/PMMA/PC) and a TFT-LCD liquid crystal panel. Make a touch panel module. The capacitive touch panel uses the capacitance change generated by the electrostatic combination between the transparent electrode and the human body, and detects its coordinates from the induced current generated.

However, currently in the capacitive touch panel, ITO conductive material is sputtered on the plastic plate or glass plate. Since ITO is sensitive to acidic substances and is easily corroded by acid, a pressure-sensitive adhesive sheet is attached to the capacitive touch panel. At the same time, it is hoped that the adhesive of the capacitive pressure-sensitive adhesive sheet has a neutral pH, but its adhesive force and glue overflow are not good.

In view of this, there is a need for a touch panel for a display device, which can protect the conductive material from being corroded by acid glue, so as to maintain the optical properties of the touch panel.

Contents of the invention

In order to overcome the above defects, the present invention provides a composite film structure and a touch panel with the composite film structure, which can protect conductive materials from being corroded by acid glue, thereby maintaining the optical properties of the touch panel.

The technical scheme that the present invention adopts in order to solve its technical problem is:

A touch panel with a composite film structure, provided with at least one conductive layer, at least one composite film and a cover plate, the composite film has a resistive adhesive layer and a capacitive adhesive layer stacked up and down, And the composite film is attached to the conductive layer at its capacitive adhesive layer; the cover plate is attached to the resistive adhesive layer of the outermost composite film.

The thickness of the resistive adhesive layer is 12 to 200 microns.

The thickness of the capacitive adhesive layer is 12 to 200 microns.

It also includes a light-transmitting layer formed between the resistive adhesive layer and the capacitive adhesive layer of the composite film.

The thickness of the transparent layer is 25 to 300 microns.

There are several conductive layers and composite films, and each conductive layer is laminated by the composite film, wherein each conductive layer has a base material and a conductive material layer formed on the base material , and the capacitive adhesive layer of the composite film is pasted on the conductive material layer of the conductive layer.

It also includes a liquid crystal display module, and there are several composite films, and the liquid crystal display module and the conductive layer are laminated by the composite film.

A composite film structure is provided with a resistive adhesive layer and a capacitive adhesive layer stacked up and down, wherein the thicknesses of the resistive adhesive layer and the capacitive adhesive layer are respectively 12 to 200 microns.

It also includes a light-transmitting layer formed between the resistive adhesive layer and the capacitive adhesive layer.

The thickness of the transparent layer is 25 to 300 microns.

The beneficial effect of the present invention is that: the present invention utilizes the composite film with resistive adhesive layer and capacitive adhesive layer stacked up and down, so that the capacitive adhesive layer and the conductive layer of the composite film are bonded to prevent The acidic glue of the resistive adhesive layer diffuses into the conductive layer to protect the conductive layer from being corroded by the acidic glue; at the same time, the composite film of the present invention can also avoid remaining air bubbles and maintain the optical characteristics of the touch panel.

Description of drawings

Fig. 1 is the structural schematic diagram of the composite film of embodiment 1 of the present invention;

Fig. 2 is a schematic structural diagram of a composite film according to Embodiment 2 of the present invention;

3 is a schematic structural view of a touch panel with a composite film structure according to Embodiment 3 of the present invention;

FIG. 4 is a schematic structural diagram of a touch panel with a composite film structure according to Embodiment 4 of the present invention.

Detailed ways

The specific implementation of the present invention is described below through specific examples, and those skilled in the art can easily understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented in other different ways, that is, various modifications and changes can be made without departing from the disclosed scope of the present invention.

Embodiment 1: A composite film structure, as shown in Figure 1, the composite film 100 is composed of a resistive adhesive layer 110 and a capacitive adhesive layer 120 formed on the resistive adhesive layer 110, wherein , the thicknesses of the resistive adhesive layer 110 and the capacitive adhesive layer 120 are respectively between 12 and 200 microns.

Embodiment 2: A composite film structure, as shown in Figure 2, the composite film 200 includes a resistive adhesive layer 210 and a capacitive adhesive layer 220 formed on the resistive adhesive layer 210, and Including a transparent layer 230 formed between the resistive adhesive layer 210 and the capacitive adhesive layer 220, the transparent layer 230 is used to further prevent the acid glue of the resistive adhesive layer 210 from diffusing into the capacitive adhesive layer 220 , and also due to the sufficient thickness, during the subsequent manufacturing of the touch panel, the air bubbles between the cover plate and the composite film are avoided during the process of laminating the cover plate.

Examples of the light-transmitting layer 230 include a light-transmitting layer made of polycarbonate, a light-transmitting layer made of acrylic resin, a light-transmitting layer made of polyester, or a light-transmitting layer made of triacetyl cellulose. The light-transmitting layer is preferably made of polycarbonate.

The light-transmitting layer can be a single-sublayer or multi-sub-layer light-transmitting layer made of a single material or a combination of two or more materials.

Preferably, the thickness of the transparent layer is 25-300 microns, and the thicknesses of the resistive adhesive layer and the capacitive adhesive layer are respectively between 12-200 microns.

The resistive adhesive layer of the composite film of the present invention may be formed by reacting an acrylic polymer and an oligomer with an isocyanate compound, wherein the weight average molecular weight of the acrylic polymer is 500,000 to 900,000, and the polymer has an The monomer contains at least one (meth)acrylic acid alkyl ester (wherein, the alkyl group contains 4 to 12 carbon atoms) as the main monomer component (for example: methyl (meth)acrylate, ethyl (meth)acrylate , n-butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate) and at least one A carboxyl-containing monomer. The weight average molecular weight of the oligomer is 3000 to 6000, and the monomer of the oligomer contains at least one ethylenically unsaturated monomer as a main monomer component, and the monomer of the oligomer used is not particularly limited, as long as It is an ethylenically unsaturated monomer, and a homopolymer with a glass transition temperature ( _Tg ) of 60 to 190°C and a ring structure can be obtained, such as a ring-containing olefin with a _Tg of 60 to 190°C Unsaturated monomers, examples of which are (but not limited to): (meth)acrylates containing non-aromatic rings, such as cycloalkyl (meth)acrylates, such as cyclohexyl (meth)acrylate and (meth)acrylate base) isobornyl acrylate; (meth)acrylates containing aromatic rings, such as aryl (meth)acrylates, such as phenyl (meth)acrylates, aryloxyalkyl (meth)acrylates, Such as phenoxyethyl (meth)acrylate, and arylalkyl (meth)acrylates, such as benzyl (meth)acrylate; and styrene monomers, such as styrene and α-methylstyrene.

The capacitive adhesive layer of the composite film of the present invention can be formed by the reaction of acrylic polymers and oligomers with isocyanate compounds, but a catalyst needs to be added during the reaction process, and the acrylic polymers and oligomers cannot contain acid groups .

For example, the acrylic polymer used in the present invention can be (but not limited to): polymethyl (meth)acrylate, polyethyl (meth)acrylate, poly-n-butyl (meth)acrylate, Polyisobutyl (meth)acrylate, polytert-butyl (meth)acrylate, poly-n-octyl (meth)acrylate, polyisooctyl (meth)acrylate.

The oligomer used in the present invention can be, for example (but not limited to): oligomers of vinyl esters such as vinyl acetate; oligomers containing cyano groups, such as (meth)acrylonitrile; Oligomers, such as (meth)acrylamide and N,N-dimethyl (meth)acrylamide; oligomers containing glycidyl groups, such as: glycidyl (meth)acrylate, ( 3,4-epoxycyclohexyl methyl methacrylate, epoxypropyl vinyl ether, 3,4-epoxycyclohexyl vinyl ether, epoxypropyl (methyl) allyl ether, 3,4 - Epoxy cyclohexyl (methyl) allyl ether and the like.

The isocyanate used in the present invention can be, for example (but not limited to): xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate tolylmethane diisocyanate and other aromatic polyisocyanates.

In addition, the catalyst used may be (but not limited to): ethyleneimine compounds such as N,N-hexamethylenebis(1-ethyleneimine carboxamide), methylenebis[N-(1-ethyleneimine (pyridylcarbonyl)-4-aniline], tetramethylolmethane-tris(β-aziridinylpropionate), trimethylolpropane-tris(β-aziridinylpropionate), etc., or , commercially available products such as TAZO or TAZM available from Mutual Pharmaceutical Co., Ltd.; CHEMITITE PZ-33 available from Nippon Shokubai Co., Ltd. can also be used appropriately.

Embodiment 3: A touch panel with a composite film structure, as shown in FIG. The composite film 300 of the layer 350 has a resistive adhesive layer 310 and a capacitive adhesive layer 320 stacked up and down, and the capacitive adhesive layer 320 is bonded to the conductive layer 350 . Specifically, the conductive layer of the present invention has a base material and a conductive material layer formed on the base material, such as ITO, and the capacitive adhesive layer is bonded on the conductive material layer. The touch panel of the present invention further includes a cover plate 340 attached to the resistive adhesive layer 310 of the outermost composite film 300 ; the touch panel of the present invention further includes a liquid crystal display module 360 . In this embodiment, multiple composite films 300 are provided, so as to overlap the liquid crystal display module 360 and the conductive layer 350 through the composite films 300 .

Embodiment 4: A touch panel with a composite film structure, as shown in FIG. The film 400 has a resistive adhesive layer 410 and a capacitive adhesive layer 420 stacked up and down, and the capacitive adhesive layer 420 is attached to the conductive layer 450. Specifically, the conductive layer of the present invention has a base material And a conductive material layer formed on the base material, such as ITO, the capacitive adhesive layer is attached to the conductive material layer; the touch panel also includes a cover plate 440, and the cover plate 440 is attached to the On the resistive adhesive layer 410 of the outermost composite film 400; the touch panel also includes a liquid crystal display module 460, and the liquid crystal display module 460 is attached to the innermost conductive layer 450 through the composite film 400, The composite film 400 is laminated to the liquid crystal display module 460 and the conductive layer 450 .

Preferably, the touch panel of the present invention further includes a light-transmitting layer, and the light-transmitting layer is formed between the resistive adhesive layer and the capacitive adhesive layer of the composite film, wherein the resistive adhesive layer and the capacitive The thicknesses of the adhesive layers are respectively between 12 and 200 microns, and the thickness of the transparent layer is between 25 and 300 microns.

The cover plate of the present invention is used to be in contact with a finger or a stylus, and its material can be glass, polymethyl methacrylate (PMMA), polycarbonate (PC) or polyethylene terephthalate (PET). The conductive layer has a base material and a conductive material layer formed on the base material. Preferably, the conductive layer used can be a conductive glass substrate and a conductive plastic substrate such as ITO conductive material formed on one side surface, and its example is (but not limited to): polymethyl methacrylate is made of plastic substrate, The plastic substrate made of polycarbonate or polyethylene terephthalate is made of plastic substrate, and the plastic substrate made of polyethylene terephthalate is best sputtered with ITO palladium material.

In the present invention, because of the good adhesion of the resistive adhesive layer to the covering plate, the covering plate is adhered to the resistive adhesive layer of the composite film; and because the ITO conductive material of the conductive layer is afraid of acid, the composite The capacitive adhesive layer of the type film is bonded to the conductive material layer of the conductive layer to protect the conductive layer from being corroded by acid glue.

Preparation Example 1: The preparation method of the composite film of Embodiment 1 of the present invention is as follows:

Mix 75.5 % (weight) of poly(n-butyl) acrylate, poly(meth) isobutyl acrylate and poly(meth) tert-butyl acrylate and 24 % (weight) of (meth) Resistive glue formed by reacting a mixture of acrylates, isobornyl (meth)acrylate and benzyl (meth)acrylate with 0.5% by weight of a mixture of xylylene diisocyanate and diphenylmethane diisocyanate Apply evenly on the release film, dry at 70 to 100°C for 8 minutes, then stick the release film and roll it with a roller. During the rolling process, check to confirm that the resistive film has no obvious air bubbles, and then cure it at room temperature for 3 to 7 days.

Next, 80 % (weight) of polyethyl (meth)acrylate, poly (meth) n-butyl acrylate and poly (meth) isobutyl acrylate mixture and 19 % (weight) of vinyl acetate, (Meth) acrylate and (meth) isobornyl acrylate mixed solution with 0.5% (weight) of butylene diisocyanate and cyclohexylene diisocyanate mixed solution with 0.5% (weight) of di-n-butylbis(acetyl The capacitive glue formed by the reaction of acetonyl) tin catalyst is evenly applied on the release film, dried at 70 to 100°C for 8 minutes, and then the release film is pasted and then rolled with a roller. During the rolling process, it is necessary to check to confirm that the capacitive film is free of glue. Visible bubbles, followed by aging at room temperature for 3 to 7 days.

After that, take the cut resistive film and capacitive film, tear off the release film, align the torn ends of the resistive film and capacitive film, and use the roller to roll. The rolling process needs to be checked and confirmed. The composite film test piece has no obvious air bubbles.

Preparation Example 2: The preparation method of the composite film of Embodiment 2 of the present invention is as follows:

Mix 75.5 % (weight) of poly(n-butyl) acrylate, poly(meth) isobutyl acrylate and poly(meth) tert-butyl acrylate and 24 % (weight) of (meth) Resistive glue formed by reacting a mixture of acrylates, isobornyl (meth)acrylate and benzyl (meth)acrylate with 0.5% by weight of a mixture of xylylene diisocyanate and diphenylmethane diisocyanate Apply evenly on the release film, dry at 70 to 100°C for 8 minutes, then stick the release film and roll it with a roller. During the rolling process, check to confirm that the capacitive film has no obvious air bubbles, and then cure it at room temperature for 3 to 7 days.

Next, 80% (weight) of polyethyl (meth)acrylate, poly(meth)acrylate n-butyl and poly(meth)acrylate isobutyl mixed solution and 19% (weight) of vinyl acetate , (meth) acrylate and (meth) isobornyl acrylate mixed solution with 0.5% (weight) of butylene diisocyanate and cyclohexylene diisocyanate mixed solution with 0.5% (weight) of di-n-butylbis( The capacitive glue formed by the reaction of acetylacetonate-tin catalase is evenly applied on the release film, dried at 100°C for 8 minutes, and then the release film is pasted and then rolled with a roller. During the rolling process, the capacitive glue must be checked and confirmed. The films were free of obvious air bubbles, and then aged at room temperature for 3 to 7 days.

After that, take the cut resistive film, capacitive film and transparent plastic substrate made of polyethylene terephthalate, tear off the release film, and align the torn ends of the resistive film and capacitive film. Roll on both sides of the transparent plastic substrate and use rollers. During the rolling process, check to confirm that there are no obvious air bubbles on the composite film test piece.

Test example: The composite film prepared according to the structure of Examples 1 and 2 and the method of Preparation Examples 1 and 2 was used as a test piece, and the test piece was tested for peel strength, glue overflow, weather resistance and optical properties , and the test results are recorded in Table 2.

1. Peel strength test

According to ASTM-D3330, use composite film test pieces with different thicknesses from test pieces 1 to 4 in Table 2. After tearing off the release film, stick them on glass (cover plate and ITO-coated conductive glass) or steel plate ( Fix it on the side of the touch panel), carefully avoid air bubbles when laminating, and then maintain the temperature at 23°C and the relative humidity at 50% for 30 minutes, use a universal tensile testing machine (JIA-802-PC), at a peeling angle of Peel strength was measured at 180° and a peel rate of 300 mm/min.

2. Glue overflow test

Use the composite film test pieces with different thicknesses from test pieces 1 to 4 in Table 2. After tearing off one side of the release film, use a roller to roll to cover 1 mil polyimide PI (purchased from Damai) to punch Punch holes (1/2, 1/16 inches) with a hole machine (JZ-918CQ), cover and paste 1Oz ED copper foil (purchased from Rikuang), and perform rapid pressing at 180°C at 100kgf/cm ² (pre-pressing time 10 seconds, pressing time 60 seconds). Before testing, use a spiral micrometer to measure its thickness, and its test piece size is 100mm×100mm. Here, the amount of glue overflow refers to the length (mm) measured from the edge side of the hole inwards to the extent of the glue overflow hole of the composite film after lamination.

3. Weather resistance test

Place the composite film test pieces with different thicknesses of test pieces 1 to 4 in Table 2 in a constant temperature and humidity machine (THS-C). Place it at a high temperature of 80°C for 240 hours, at a low temperature of -20°C for 240 hours, and at a high temperature and high humidity of 60°C/90%RH, check the appearance for yellowing, large bubbles, small bubbles, and Stratification occurs.

4. Optical test

Use the composite film test pieces with different thicknesses from test pieces 1 to 4 in Table 2. After tearing off the ultra-light release film, test the haze, light transmittance and chromaticity respectively.

The evaluation methods of optical properties and weather resistance are shown in Table 1 below.

Haze: H=「Td/Tt」×100%; Td: Diffuse transmittance, Tt: Total transmittance.

Light transmittance: T(Transmittance%)=I ₀ /I ₁ ; I ₀ : Intensity of incident light, I ₁ : Intensity of all transmitted light.

Chromaticity: The b value measurement is less than 0.5%, and the b value is based on the data of yellow and blue light (measured according to ASTM E308 standard).

Table I

Table II

A single-layer resistive or capacitive adhesive layer (taken from Asia Electric Materials Co., Ltd.) was tested in the same way as a comparative example, and the results are recorded in Table 3.

Table three

According to the test results in Table 2 and Table 3, it can be seen that the composite film of the present invention has a large amount of glue overflow, can reduce the phenomenon of air bubbles in the process of laminating the covering board, and has excellent optical properties, and is suitable for using fingers or The stylus is used as the LCD panel of the operation interface.

The above-mentioned embodiments are only illustrative to illustrate the principles and effects of the present invention, but are not intended to limit the present invention. The protection scope of the present invention should be listed in the claims.

Claims (10)

1. A touch panel with a composite film structure, characterized in that: at least one conductive layer, at least one composite film and a cover plate are provided, and the composite film has resistive adhesive layers stacked up and down and a capacitive adhesive layer, and the composite film is attached to the conductive layer at the capacitive adhesive layer; the cover plate is attached to the resistive adhesive layer of the outermost composite film. 2 . The touch panel with composite film structure as claimed in claim 1 , wherein the resistive adhesive layer has a thickness of 12 to 200 microns. 3 . The touch panel with composite film structure as claimed in claim 1 , wherein the capacitive adhesive layer has a thickness of 12 to 200 microns. 4 . 4. The touch panel with a composite film structure according to claim 1, further comprising a light-transmitting layer formed on the resistive adhesive layer and the capacitive adhesive layer of the composite film. between the adhesive layers. 5 . The touch panel with composite film structure as claimed in claim 4 , wherein the thickness of the transparent layer is 25 to 300 microns. 6. The touch panel with composite film structure as claimed in claim 1, characterized in that: there are several conductive layers and composite films, and each conductive layer is laminated by the composite film , wherein each of the conductive layers has a substrate and a conductive material layer formed on the substrate, and the capacitive adhesive layer of the composite film is attached to the conductive material layer of the conductive layer. 7. The touch panel with composite film structure as claimed in claim 1, characterized in that: it also includes a liquid crystal display module, and the composite film is provided with several, and the liquid crystal display module and the conductive layer are composed of The composite films are spliced. 8. A composite film structure, characterized in that: a resistive adhesive layer and a capacitive adhesive layer stacked up and down are provided, wherein the thicknesses of the resistive adhesive layer and the capacitive adhesive layer are respectively 12 to 200 microns. 9. The composite film structure as claimed in claim 8, further comprising a light-transmitting layer formed between the resistive adhesive layer and the capacitive adhesive layer. 10. The composite film structure as claimed in claim 9, wherein the thickness of the transparent layer is 25 to 300 microns.

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