KR20090070652A - Conductive sheet for absorbing impact and sealing - Google Patents

Abstract

A conductive sheet for impact absorption and sealing is provided to prevent damage of components due to external shock which is mounted on internal and external wall of electronic devices, and to prevent inflow of contaminants. A conductive sheet(10) for impact absorption and sealing includes an adhesive layer(2), a polyurethane layer(4), and a conductive coating layer(6). Thickness of the sheet is 0.1 -2.0 mm. A surface resistance value of the sheet is 106-1011ohm/sq. Tensile strength of the sheet is 500 kgf/cm^2. An extension rate of the sheet is 100 - 600 %. The adhesive layer is formed one or more selected from a group consisting of acrylic oligomer, acrylic monomer, an acetate-based polymer and a styrene-based polymer.

Description

Conductive Sheet for Shock Absorption and Sealing {CONDUCTIVE SHEET FOR ABSORBING IMPACT AND SEALING}

The present invention relates to a shock absorbing and sealing conductive sheet, and more particularly, to be introduced into the interior and exterior of various electronic devices to prevent damage to components caused by external shocks, and to prevent contamination such as dust from being introduced from the outside. The present invention relates to a conductive sheet for shock absorption and sealing that prevents interference in static and dynamic states by charging and protects electronic devices.

Electronic devices such as mobile phones, hard disk drives (HDDs), televisions and liquid crystal displays are made up of precise mechanical components and electronic devices. The electronic devices are easily broken or broken when a physical shock is applied from the outside, and contaminants such as dust are introduced from the outside, disrupting air flow in the electronic device, causing overheating of the electronic device, and shortening the lifespan. . In addition, various harmful electromagnetic waves or electromagnetic waves generated by the devices in the electronic device may disrupt the functions of the surrounding electric and electronic devices, reduce performance, shorten the lifespan, and cause the generation of defective products.

In order to solve these problems, in general, electronic devices are provided with a sheet that serves as a sealing (sealing) that can absorb the impact from the outside and close the gap of the exterior.

Korean Patent Laid-Open Publication No. 2002-0015239 maintains a gap between the panel guide and the light guide plate in order to prevent the optical sheets from being damaged or wrinkled by the guide panel of the liquid crystal display device. It is mentioned to install a separate spacing / heat blocking member to block inflow. In this case, a pad made of silicon is used as a material of the gap maintaining / heat blocking member.

Korean Patent Laid-Open Publication No. 2005-0058055 discloses forming a separate elastic layer between substrates in order to prevent gravity failure of the liquid crystal display device. At this time, the elastic layer is prepared by preparing a paste containing an aromatic diisocyanate, polyol and 1,4-butanediol, and then coated on a substrate to form a polyurethane rubber layer.

The gap retaining / heat-blocking member or elastic layer formed in the above-described Patent Publication Nos. 2002-0015239 and 2005-0058055 give elasticity and high sealing effect to home appliances and electronics by using silicone or polyurethane rubber, respectively. Doing.

However, in order to form an elastic layer as described in Korean Patent Laid-Open Publication No. 2005-0058055, there is a process inconvenience in that a coating is performed according to a pattern after manufacture in a paste form. On the other hand, the silicon pad of the Patent Publication No. 2002-0015239 has the advantage that it can be very easily applied to various home appliances and electronic devices are manufactured in the form of a sheet.

Sheets such as silicone pads are used by attaching a double-sided adhesive tape on one side of the pad to an electronic device or by coating an acrylic pressure-sensitive adhesive on one side of the pad and then attaching it to a home appliance or an electronic device. However, in the case of the silicon sheet, since the silicon itself used as a raw material of the pad has a low surface tension and low adhesive force to an adhesive tape or an adhesive, a problem arises that the silicon sheet is easily peeled off after being attached to the electronic device.

In order to solve this problem, it is required to prevent the malfunction of the device due to the charging phenomenon, and to develop a material having excellent adhesive strength, dispersing the impact applied from the outside, and excellent sealing effect.

Another object of the present invention is to be introduced into the interior and exterior of various electronic devices to prevent damage to the components due to external impact, to prevent the introduction of pollutants such as dust from the outside and to prevent the product from various electromagnetic waves or electromagnetic waves in the electronic device It is to provide a conductive sheet for shock absorption and sealing to protect the.

In order to achieve the above object, the present invention

Provided is a conductive sheet for shock absorption and sealing in which an adhesive layer, a polyurethane layer, and a surface coating layer are sequentially stacked.

The conductive sheet for shock absorption and sealing according to the present invention has physical properties of 0.1 to 2.0 mm in thickness, surface resistance of 10 ⁶ to 10 ¹¹ ohm / sq, tensile strength of 500 kgf / cm 2 or less, and elongation rate of 100 to 600%.

In addition, the shock absorbing and sealing conductive sheet may further include an adhesive auxiliary layer for improving adhesion between the polyurethane layer and the adhesive layer.

In yet another aspect, the present invention provides a method for producing a shock absorbing and sealing conductive sheet as described above.

The manufacturing method of the present invention

Preparing a polyurethane layer;

Forming an adhesive layer on one surface of the polyurethane layer; And

Forming a conductive coating layer on one surface different from the surface on which the adhesive layer of the polyurethane layer is formed

Hereinafter, the present invention will be described in detail with reference to FIGS.

The conductive sheet for shock absorbing and sealing of the present invention has properties equal to or higher than those of the conventional sealing sheet, and is inexpensive, and is easily introduced into an automated process, thereby being introduced into the interior and exterior of various electronic devices to provide external impact. It is characterized by preventing the damage of parts by, preventing the inflow of pollutants such as dust from the outside, and protecting the product from various electromagnetic waves or electromagnetic waves in the electronic equipment.

1 is a cross-sectional view of a conductive sheet for shock absorption and sealing according to an embodiment of the present invention.

Referring to FIG. 1, the shock absorbing and sealing conductive sheet 10 has a structure in which an adhesive layer 2, a polyurethane layer 4, and a conductive coating layer 6 are sequentially stacked.

The adhesive layer 2 included in the conductive sheet 10 of the present invention provides adhesiveness to the sheet so that the sheet can be attached to the interior and exterior of the electronic device.

The material of the adhesive layer 2 may be a pressure-sensitive adhesive composition commonly used in this field, and is not particularly limited in the present invention. Representative examples thereof may be one selected from the group consisting of acrylic monomers, acrylic oligomers, acrylic polymers, acetate polymers, styrene polymers, and the like, preferably vinyl acetate, methyl methacrylate, ethyl acetoacrylate, and the like. At least one selected from the group consisting of sulfonated polystyrene can be used.

At this time, the adhesive layer 2 should have physical properties that the conductive sheet 10 can be attached to the electronic device with sufficient adhesive strength. That is, the peel strength of the adhesive layer 2 is preferably at least 150 gr / cm to prevent the conductive sheet 10 from being released from its original position during the assembling and use of the product. In addition, the thickness of the adhesive layer (2) can be adjusted according to the adhesive properties of the material, but in order to maintain a minimum adhesive force is preferably 5 ㎛ or more, 120 ㎛ to prevent the conductive sheet 10 is too thick It is preferable that it is the following.

The adhesive layer 2 of the conductive sheet 10 according to the present invention is formed directly on the polyurethane layer 4 to be described later, or made by laminating after the production in a separate film form. In the case of forming directly, conventional methods such as a screen printing method, a spray coating method or a coating method using a doctor blade may be used depending on the viscosity of the adhesive composition. In addition, formation by lamination is performed by forming the adhesion layer 2 by the above application | coating or spraying on another film, and laminating | stacking with the polyurethane layer 4, and removing a film.

In particular, the polyurethane layer 4 directly absorbs and disperses the impact applied from the outside when the conductive sheet 10 is installed on the inside and the outside of the electronic device to protect the electronic device, and suppresses the inflow of external pollutants. It acts as a sealant.

As the material of the polyurethane layer 4, a soft polyurethane, a semi-hard polyurethane or a hard polyurethane may be used, and among these, a soft polyurethane is most preferable. Specifically, the polyurethane layer 4 includes methylene diphenyl isocyanate (MDI), toluene diisocyanate (TDI), methylene diphenyl isocyanate (MDI) oligomer, toluene diisocyanate (TDI) oligomer, and carbodiimide modified methylene diisocyanate. It can be prepared by reacting at least one diisocyanate selected from the group consisting of, and at least one polyol mixture selected from the group consisting of polypropylene glycol, polytetramethylene glycol, and polyethylene glycol. The polyurethane layer preferably has a density of 0.1 gr / cm ³ to 0.6 gr / cm ³ in order to act as a sealant to absorb and disperse the impact to protect electronic devices and to suppress the influx of external pollutants.

In addition, a crosslinking agent may be additionally used in order to increase the crosslinking rate of the polyol compound and the prepolymer and to sufficiently cause crosslinking, wherein the content thereof is used in an amount of 0 to 100 parts by weight based on 100 parts by weight of the prepolymer.

The crosslinking agent may be a conventional one, but is not limited in the present invention, preferably trimethylolpropane, triethanolamine, pentaerythritol, toluenediamine, toluene diamine, ethylenediamine (ethylenediamine), glycerine, oxypropylated ethylene diamine, hexamethylene diamine, m-phenylene diamine, diethanolamine and triethanolamine (triethanolamine) can be used a compound selected from the group consisting of.

In addition, the polyurethane layer (4) is preferably installed in the product to prevent permanent deformation of the conductive sheet 10 after a long time elapsed is preferably a compression compression rate of 0.1 to 20%, and adheres enough to the electronic device In order to ensure that the elongation is preferably from 100 to 600%.

At this time, the thickness of the polyurethane layer 4 may vary depending on the applied electronic device, but in order to maintain a minimum shock absorption effect is preferably at least 0.1 mm, and maintains the sealing effect even on the surface of the uneven electronic device, It is preferable that it is 2.0 mm or less in order to be able to make light and thin the electronic device.

Polyurethane layer (4) according to the present invention is manufactured in the form of a sheet, which is commonly used in this field by extrusion, injection molding, calendering (calendering), inflation (inflation) or casting (casting) processing method It can manufacture.

For example, the polyurethane layer 4 may be manufactured by a two-component mixing process by a casting process. In the two-component mixing process, at least one polyol mixture selected from the group consisting of polypropylene glycol, polytetramethylene glycol, and polyethylene glycol, methylene diphenyl isocyanate (MDI), toluene diisocyanate (TDI), and methylene diphenyl isocyanate The main raw material is at least one diisocyanate prepolymer selected from the group consisting of (MDI) oligomers, toluene diisocyanate (TDI) oligomers, and carbodiimide-modified methylene diisocyanates.

The raw material may be injected into a mold after being metered and mixed in a batch or continuous manner, or coated on a base film to cure to form a polyurethane layer.

When using such a casting method, there is no solvent or volatile substance, there is an advantage that can be made by a single product of a certain thickness. In addition, since the polyurethane resin produced by the casting process has a three-dimensional network structure, it is possible to secure a low hardness and sufficient tensile strength at the same time without using an additive such as a plasticizer, and also by applying the casting process continuously. It is possible to mass-produce the conductive sheet 10 according to the roll form.

Meanwhile, the conductive coating layer 6 included in the conductive sheet 10 of the present invention is formed on the polyurethane layer 4 and is positioned at the outermost portion of the conductive sheet 10 so as to be in a static and dynamic state due to electrification. In addition to the role of a sealing agent to prevent obstacles in the electronic device, and to prevent the introduction of contaminants into the electronic device, to protect the surface of the conductive sheet 10 and give the appropriate frictional resistance to the surface of the sheet in the form of rolls and sheets Makes it possible.

The material of the conductive coating layer 6 is to form a coating layer by blending the conductive filler to the coating material commonly used in this field. As a representative conductive filler, at least one selected from the group consisting of copper, nickel, aluminum, carbon black, graphite, silver, and the like may be used. Representative examples of coating materials used with conductive fillers include acrylic polymers prepared from acrylic monomers or oligomers including silicon acrylate, silicon methacrylate, acrylic acid, methacrylic acid, methyl methacrylate, and methyl methacrylate. ; Urethane-acrylate copolymers or blends; Or one or more selected from the group consisting of polyethylene-based polymers including polypropylene, polyvinylidene fluoride, and teflon. In order to protect the product from various electromagnetic waves or electromagnetic waves in the electronic device and to prevent appearance defects of the coating layer and cracking during assembly, the content of the conductive filler is preferably 5 to 50 parts by weight based on 100 parts by weight of the coating material.

In this case, the conductive coating layer 6 preferably has a peel strength of at least 50 gr / cm in order to prevent peeling from the polyurethane layer 4. In addition, when the conductive sheet 10 of the present invention is manually assembled to an electronic device, in order to apply a uniform and constant force to the surface of the conductive sheet 10, the surface coating layer 6 is measured with the glass relative surface. It is preferable that the calculated friction coefficient is 2 to 20. The thickness of the conductive coating layer 6 can be adjusted according to the properties of the material, and in order to prevent the appearance of the conductive sheet 10 from deteriorating and to maintain a uniform coefficient of friction, the thickness of the conductive coating layer 6 is preferably 0.5 µm or more and cracks during assembly. It is preferable that it is 10 micrometers or less in order to prevent this from occurring.

The conductive coating layer 6 according to the present invention is formed on the polyurethane layer 4 in the same manner as the adhesive layer 2 or made of a separate film and then laminated. In the case of forming directly, conventional methods such as a screen printing method, a spray coating method or a coating method using a doctor blade may be used depending on the viscosity of the surface coating composition. In addition, the formation by lamination is performed by forming a surface coating layer by coating or spraying as described above on a separate release film, then laminating with the polyurethane layer 4 to remove the release film.

Such a shock-absorbing and sealing conductive sheet 10 of the present invention is composed of a pressure-sensitive adhesive layer (2), a polyurethane layer (4) and a conductive coating layer (6) can be introduced into a variety of electronic devices. In this case, the conductive sheet 10 may further include a separate layer as needed, and preferably further include an adhesive auxiliary layer 8 between the adhesive layer 2 and the polyurethane layer 4. .

2 is a cross-sectional view of the conductive sheet 20 for shock absorption and sealing according to another embodiment of the present invention.

Referring to FIG. 2, the shock absorbing and sealing conductive sheet 20 of the present invention includes an adhesive layer 2, an adhesive auxiliary layer 8, a polyurethane layer 4, and a conductive coating layer 6. At this time, the adhesive layer 2, the polyurethane layer 4 and the conductive coating layer 6 follows the above.

In addition, the adhesive auxiliary layer 8 is used to provide more stable adhesive force to the conductive sheet 20, and is made of a composition having excellent compatibility with the materials of the polyurethane layer 4 and the adhesive layer 2.

Specifically, at least one adhesive auxiliary layer 8 is selected from the group consisting of urethane acrylate having a vinyl group introduced into the terminal of the low molecular weight oligourethane, a copolymer of urethane acrylate and an acrylic monomer, and a mixture of urethane and acrylic. Can be used. In addition, it is preferable that the adhesion auxiliary layer 8 is formed to a thickness of 0.5 to 10 μm, and the peel strength to the polyurethane layer 4 is preferably at least 300 gr / cm.

The conductive sheet for shock absorption and sealing according to the present invention having the above configuration has a thickness of 0.1 to 2.0 mm, a surface resistance of 10 ⁶ to 10 ¹¹ ohm / sq, a tensile strength of 500 kgf / cm 2 or less, and an elongation rate. It has a physical property of 100 to 600%.

Specifically, the conductive sheet according to the present invention may vary in thickness depending on the applied electronic device, but preferably 0.1 mm or more in order to maintain a minimum shock absorption effect, and the sealing effect on the surface of the uneven electronic device is severe. It is preferable that the thickness be 2.0 mm or less in order to maintain the thickness of the electronic device and to make the electronic device light and simple. In addition, the conductive sheet according to the present invention preferably has a surface resistance of 10 ⁶ to 10 ¹¹ ohm / sq in order to prevent charging in a dynamic and static state generated in the electronic device. In addition, the conductive sheet according to the present invention has a tensile strength of 500 kgf / cm 2 or less, preferably 50 kgf / cm 2 to 500 kgf / in order to exhibit sufficient shock absorption performance while preventing excessive force from being applied to the electronic device. It is good that it is cm <2>. In addition, the conductive sheet according to the present invention is preferably 100 to 600% elongation in order to be attached in close contact with the electronic device sufficiently.

On the other hand, the conductive sheet for shock absorption and sealing according to the present invention can be applied to a conventional sheet process. Specifically, a polyurethane layer is manufactured using a raw material of polyurethane, a surface conductive coating composition is coated on the sheet to form a conductive coating layer, and an adhesive layer is formed on the other side of the polyurethane layer on which the surface coating layer is not formed. Form and manufacture.

In particular, the conductive sheet according to the present invention can be produced by using a polyurethane material, the sheet can be manufactured in an automated process, and the process of assembling the sheet in an electronic device can also be automated to increase the production speed.

As described above, the shock-absorbing and sealing conductive sheet prepared according to the present invention exhibits the same or better performance as the shock-absorbing and sealing properties compared to the existing sheet by using the conductive coating layer, and prevents the obstacles caused by the charging phenomenon. There is an advantage.

Hereinafter, preferred examples and comparative examples are presented to aid in understanding the present invention. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto.

[ Example  1 to 3]

100 parts by weight of polypropylene glycol (BASF, trade name LUPRANOL L1100, molecular weight 1,100) and 600 parts by weight of methylene diphenyl diisocyanate (TCI) were stirred under a nitrogen atmosphere at 80 ° C. for 4 hours to prepare a prepolymer.

220 parts by weight of polypropylene glycol (BASF, trade name LUPRANOL L1100, molecular weight 1,100), 620 parts by weight of polypropylene glycol (BASF company, trade name LUPRANOL L2030, molecular weight 3,100), 1,4-butanediol (1,4-Butanediol) (Acros G) 90 parts by weight and 0.3 parts by weight of a catalyst, dibutyl tin dilaurate (Air product, trade name T-12,) were added thereto, followed by stirring at 50 ° C. for 4 hours under reduced pressure to obtain a polyol mixture.

90 parts by weight of the prepolymer was added to 100 parts by weight of the polyol mixture, stirred at 25 ° C. for 10 seconds, and then coated on a release paper and cured at 90 ° C. for 6 hours to prepare a polyurethane layer having a thickness of 1 mm.

Subsequently, 100 parts by weight of urethane acrylate (Sartome, trade name CN962) and 3 parts by weight of silica (Fuji-Silysia, trade name Silisya SY-161) on the polyurethane layer, 10 to 25 parts by weight of graphite (Example 1 : 10 parts by weight, Example 2: 18 parts by weight, Example 3: 25 parts by weight) was applied, and then UV cured to form a conductive coating layer of 3 ㎛ thickness.

Next, an acrylic double-sided adhesive tape [Three (3M), trade name EAD 217] having a peel strength of 450 gf / cm and a thickness of 120 μm was laminated on the other side of the polyurethane layer on which the conductive coating layer was not formed. The sealing sheet was manufactured.

[ Comparative example ]

An acrylic double-sided adhesive tape (Three (3M), trade name EAD 217) having a thickness of 120 µm was laminated on a polyurethane sheet (trade name esorba SEC050SD, SK utis).

[ Experimental Example ]

For the sheets prepared through Examples and Comparative Examples, surface resistance, tensile strength, elongation rate, peeling strength were measured as follows, and the results are shown in Table 1 below.

Experimental Example  1: surface resistance

After leaving a sample for 24 hours at 23 ° C. and 50% RH, the surface resistance of the sample was measured according to ASTM D257.

Experimental Example  2: The tensile strength

Samples cut to a width of 20 mm and a length of 130 mm were left for 24 hours at 23 ° C. and 50% RH, and then tensioned using an Instron Universal Testing Machine according to ASTM D 3574. Tensile strength was measured at a speed of 500 mm / min.

Experimental Example  3: Elongation

After leaving the sample at 23 ° C. and 50% RH for 24 hours, the elongation at the point where the specimen was cut was measured according to ASTM D 3574.

Experimental Example  4: Peel strength

Samples cut to a width of 20 mm and a length of 150 mm are allowed to stand at 23 ° C. and 50% RH for 24 hours, then peeled off at a tensile rate of 500 mm / min using an Instron Universal Testing Machine. Intensity was measured. The result was the average of the measurements.

division Surface resistance (ohm / sq) Tensile Strength (kgf / ㎠) Elongation (%) Peel Strength (gf / cm) Example 1 10 ^ 11 2.9 120 450 Example 2 10 ^ 9 ↑ ↑ ↑ Example 3 10 ^ 8 ↑ ↑ ↑ Comparative example 10 ^ 12 2.3 150 450

1 is a cross-sectional view of a conductive sheet for shock absorption and sealing according to an embodiment of the present invention,

2 is a cross-sectional view of a conductive sheet for shock absorption and sealing according to another embodiment of the present invention.

<Description of Drawing>

10 and 20: conductive sheet

2: adhesive layer

4: polyurethane layer

6: conductive coating layer

8: adhesive auxiliary layer

Claims (18)

A conductive sheet for shock absorption and sealing in which an adhesive layer, a polyurethane layer, and a conductive coating layer are sequentially stacked. The method of claim 1, The sheet has a thickness of 0.1 to 2.0 mm shock absorbing and sealing conductive sheet.         The method of claim 1 The sheet has a surface resistance value of 10 ⁶ to 10 ¹¹ ohm / sq, the shock absorbing and sealing conductive sheet The method of claim 1, The sheet is a conductive sheet for shock absorption and sealing having a tensile strength of 500 kgf / ㎠ or less The method of claim 1, The sheet is 100 to 600% elongation of the shock absorbing and sealing conductive sheet. The method of claim 1, The adhesive layer is a shock absorbing and sealing conductive sheet formed from one or more selected from the group consisting of an acrylic monomer, an acrylic oligomer, an acrylic polymer, an acetate polymer and a styrene polymer. The method of claim 1, The adhesive layer is a shock absorbing and sealing conductive sheet having a peel strength of 150 gr / ㎝ or more. The method of claim 1, The adhesive layer is a shock absorbing and sealing conductive sheet having a thickness of 5 to 120 ㎛. The method of claim 1, The polyurethane layer is selected from the group consisting of methylene diphenyl isocyanate (MDI), toluene diisocyanate (TDI), methylene diphenyl isocyanate (MDI) oligomer, toluene diisocyanate (TDI) oligomer, and carbodiimide modified methylene diisocyanate A conductive sheet for shock absorption and sealing, which is prepared by reacting at least one diisocyanate with at least one polyol mixture selected from the group consisting of polypropylene glycol, polytetramethylene glycol, and polyethylene glycol. The method of claim 1, The polyurethane layer is a shock absorbing and sealing conductive sheet is 0.1 to 2.0 mm in thickness. The method of claim 1, The conductive coating layer At least one conductive filler selected from the group consisting of copper, nickel, aluminum, carbon black, graphite and silver, At least one coating material selected from the group consisting of acrylic polymers, urethane-acrylate copolymers or blends, and vinyl polymers Formed by mixing, the shock absorbing and sealing conductive sheet. The method of claim 1, The conductive coating layer is a shock absorbing and sealing conductive sheet having a friction coefficient of 2 to 20 to the glass relative surface. The method of claim 1, The conductive coating layer is 0.5 ~ 10 ㎛ thickness of the shock absorbing and sealing dosite. The method of claim 1, The conductive sheet for shock absorption and sealing further comprising an adhesive auxiliary layer laminated between the polyurethane layer and the adhesive layer. The method of claim 14, The pressure-sensitive adhesive auxiliary layer is a shock absorbing and sealing conductive sheet is one or more selected from the group consisting of urethane acrylates, copolymers of urethane acrylates and acrylic monomers, and a mixture of urethane and acrylic. The method of claim 14, The adhesive auxiliary layer is a shock absorbing and sealing conductive sheet having a peel strength of 300 gr / ㎝ or more with respect to the polyurethane layer. The method of claim 14, The adhesive auxiliary layer has a thickness of 0.5 to 10 ㎛ shock absorbing and sealing conductive sheet. Preparing a polyurethane layer; Forming an adhesive layer on one surface of the polyurethane layer; And Forming a conductive coating layer on the other surface and the adhesive layer of the polyurethane layer is formed from one or more selected from the group consisting of an acrylic monomer, an acrylic oligomer, an acrylic polymer, an acetate polymer and a styrene polymer, The conductive coating layer is one or more conductive fillers selected from the group consisting of copper, nickel, aluminum, carbon black, graphite and silver, At least one coating material selected from the group consisting of acrylic polymers, urethane-acrylate copolymers or blends, and vinyl polymers Formed by mixing, Method for producing a conductive sheet for shock absorption and sealing.

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