KR101078353B1 - Method of preparing sheet for absorbing impact and sealing comprising adhesive layer - Google Patents

Abstract

The present invention relates to a method for manufacturing a shock absorbing and sealing sheet, and more particularly, forming an adhesive layer having a thickness of 5 μm to 150 μm by applying an adhesive to one surface of a support film layer; And forming a shock absorbing foam layer having a thickness of 0.05 mm to 10 mm by coating the shock absorbing foam raw material on the other surface of the support film layer on which the pressure-sensitive adhesive layer is formed and curing the coated foam raw material. It relates to a method for producing a shock absorbing and sealing sheet.

In the manufacturing method of the present invention, unlike the previously known double-sided tape attachment method, a continuous process of forming a pressure-sensitive adhesive layer by applying an adhesive to one surface of the support film, and continuously forming a shock-absorbing foam layer on the other side of the support film Regarding, it is possible to simplify the manufacturing process has the advantage of high production efficiency. In addition, the manufacturing method according to the present invention, compared to the previous sheet manufacturing process, can efficiently produce a shock absorbing and sealing sheet having a thinner thickness and equivalent properties or more, and can reduce the loss of raw materials and the incidence of defects. It can be minimized.

Description

The manufacturing method of the sheet for impact absorption and sealing containing an adhesive layer {METHOD OF PREPARING SHEET FOR ABSORBING IMPACT AND SEALING COMPRISING ADHESIVE LAYER}

The present invention relates to a method for producing a shock absorbing and sealing sheet comprising an adhesive layer.

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 easily fail or break when a physical shock is applied from the outside. In addition, contaminants such as dust introduced from the outside may interfere with the air flow in the electronic device, causing overheating of the electronic device, thereby reducing the life of the electronic device.

In order to solve these problems, in general, electronic devices are provided with a sheet that acts as a sealing agent to absorb shocks from the outside and close the gap of the exterior.

For example, Korean Patent Laid-Open Publication No. 2002-0015239 prevents optical sheets from being damaged or wrinkled by a guide panel of a liquid crystal display device, maintains a gap between the panel guide and the light guide plate, and maintains a gap therebetween. It mentions the installation of a separate space keeping / heat blocking member to block the inflow of heat and foreign substances. In this case, a pad made of silicon is used as the gap maintaining / heat blocking member. In addition, Korean Laid-Open Patent Publication No. 2005-0058055 discloses forming a separate elastic layer between substrates in order to prevent gravity failure of the liquid crystal display device. In this case, the elastic layer is prepared by preparing a paste containing an aromatic diisocyanate, polyol and 1,4-butanediol, coating on a substrate, and then curing 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 provide elastic and high sealing effects 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, after preparing the elastic layer composition in the form of a paste, there is a process inconvenience in that coating must be performed according to a pattern. On the other hand, the silicon pad of the Patent Publication No. 2002-0015239 has the advantage that it is manufactured in the form of a sheet can be very easily applied to various home appliances and electronic devices. Sheets such as silicone pads are used by attaching a double-sided adhesive tape to one side of the pad, or by attaching an acrylic pressure-sensitive adhesive to one side of the pad and then attaching to the electronic device. However, in the case of the silicon sheet, since the surface tension of the silicon itself used as a raw material of the pad is low and the adhesive force to the adhesive tape or the adhesive is low, a problem arises that the silicon sheet is easily peeled off after being attached to the electronic device.

In order to solve this problem, a method of coating a separate primer on a silicon pad has been proposed. Although satisfactory adhesion can be obtained through the above method, the addition of a separate primer coating process complicates the process, increases manufacturing costs, and raises the environmental pollution problem due to the organic solvent contained in the primer coating composition. Thus, a method of using silicone as a material of the adhesive or the adhesive tape has been proposed as a method for increasing the adhesive force between the silicone and the adhesive without using a primer. However, this method not only lowers the adhesion but also raises the price.

In addition, a sheet of polyvinyl chloride (PVC) material has been proposed to replace silicon. However, in the case of the PVC, the resin itself is too high in order to have a large amount of plasticizer to have elasticity and sealing properties. These plasticizers are transferred to the surface of the electronic device over time, thereby contaminating the interior and parts of the electronic device, causing a malfunction of the device and shortening the lifespan. In addition, in the case of the silicone sheet, a pressure-sensitive adhesive tape or an adhesive tape is attached to the silicone pad, and the adhesion process is mainly performed by applying pressure by hand, which is a factor that greatly reduces the production speed in the continuous automation process. have.

In addition, in order to prevent the sheets from being separated during the process of assembling these sheets at the application portion of the electronic device and use, the double-sided tape is laminated and fixed. However, the use of such double-sided tape increases the thickness of the entire sheet, and when the thickness is limited, the thickness of the compressible portion is lowered. Due to the specific gravity of the non-compressed material, the compressibility of the entire sheet to be possessed by the sheet itself is lowered, and eventually, the demand for shock absorption and gap filling is not satisfied. In addition, the loss of product raw materials and the incidence of defects due to the addition of the double-sided tape application process are increased, and the productivity of the work is reduced.

In order to solve the above problems, the present invention is to reduce the number of the pressure-sensitive adhesive layer and the support film layer to be additionally applied by producing a sheet for absorbing shock and sealing using a support film layer comprising a pressure-sensitive adhesive layer during sheet production, By relatively increasing the thickness of the polyurethane layer having a high compressibility, the shock absorbing force and the sealing ability are improved, and the manufacturing technology of the shock absorbing and sealing sheet, which is simplified in the manufacturing process, has been developed to complete the present invention.

delete

Therefore, an object of the present invention is to provide a method for producing the above shock absorbing and silishing sheet.

delete

In order to achieve the above object, the present invention provides a method for producing a shock absorbing and sealing sheet as follows.

The manufacturing method of the present invention

Applying an adhesive to one surface of the support film layer to form an adhesive layer having a thickness of 5 μm to 150 μm; And

Forming a shock absorbing foam layer having a thickness of 0.05 mm to 10 mm by coating the shock absorbing foam raw material on one side of the support film layer on which the pressure-sensitive adhesive layer is formed and curing the coated foam raw material.

It may include.

In another example, the manufacturing method of the present invention

Coating a shock absorbing foam raw material on one surface of the support film layer and curing the coated foam raw material to form a shock absorbing foam layer having a thickness of 0.05 mm to 10 mm; And

Forming a pressure-sensitive adhesive layer having a thickness of 5 μm to 150 μm by applying an adhesive to a surface different from the surface of the support film layer on which the impact-absorbing foam is formed.

It may include.

The sheet manufacturing method according to the present invention may further include a step of forming a release film layer or a release paper layer by laminating a release film or release paper on the pressure-sensitive adhesive layer formed after the pressure-sensitive adhesive layer forming step.

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 5.

1 and 2 respectively show a conventional manufacturing and processing process of the shock-absorbing sheet and the manufacturing and processing process of the shock-absorbing sheet of the present invention in order. Conventional shock-absorbing sheet had to involve a process of laminating using double-sided tape to form a shock-absorbing foam layer and / or release film layer on the support film layer, according to the present invention, a support film layer with an adhesive layer formed By using, a separate lamination process is not required, and the process can be simplified, and raw material loss and defect occurrence rate can be lowered.

3 and 4 is a cross-sectional view of a conventional shock absorbing sheet laminated double-sided tape, the support film layer 10 / polyurethane layer 20 or the release film layer 40 / adhesive layer 30 The cross section comprised of the support film layer 10, the adhesive layer 30, the support film layer 10, and the polyurethane layer 20 is shown, respectively. As described above, the sheet on which the double-sided tape is laminated occupies a relatively large proportion of the thickness of the incompressible material, so that the total compression ratio of the sheet itself is low, and thus, the shock absorption rate and the sealing ability are poor.

On the other hand, Figure 5 is a cross-sectional view of the shock absorbing and sealing sheet comprising a support film layer with a pressure-sensitive adhesive layer according to the present invention, the release film layer 40 / adhesive layer 30 / support film layer 10 ) Shows a cross section composed of a polyurethane layer 20. The box indicated by the dotted red line in the figure indicates the thickness that will increase as a whole when using double-sided tape or the thickness of the polyurethane layer that will be relatively reduced when the overall thickness is constant. The sheet according to the present invention is not only excellent in the ability to prevent the damage of the component due to the external impact of the electronic device, to prevent the introduction of pollutants such as dust from the outside, and also to reduce the specific gravity of the unnecessary incompressible material layer. By minimizing, it has a relatively high thickness ratio of polyurethane on the same thickness, and thus, it has a high compression ratio, high impact absorption and excellent sealing function as compared to the product laminated the existing double-sided tape.

In the present invention, the support film layer 10 serves as a base material, and the material may be any material commonly used for shock absorbing and sealing sheets, and may be, for example, a transparent or white plastic film. Specifically, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester, polyamide, polycarbonate, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-propylene copolymer, poly It may be one or more selected from the group consisting of vinyl chloride and the like, but is not limited thereto. In order to improve the adhesiveness with respect to an adhesive layer and a polyurethane layer, you may perform a corona discharge treatment, a plasma treatment, a blast treatment, a chemical etching treatment, a primer treatment, etc. on the surface of a base film.

The support film layer 10 may give a proper support force to the sheet and when the adhesive layer is applied to the product, it is easy to control the shape to give excellent workability. In the present invention, the thickness of the support film layer 10 can be appropriately adjusted according to the product characteristics, in order to exhibit the support ability for maintaining the minimum shape is preferably 5 μm or more, the overall sheet thickness is too thick In order to prevent this, it is better to set it to 125 micrometers or less.

The pressure-sensitive adhesive layer 30 may be prepared from a pressure-sensitive adhesive material commonly used in the related art as long as it has a proper adhesive strength to other materials, for example, 1kgf or more per inch, and also has heat resistance of 60 ° C or more. Representative examples thereof include natural rubber adhesives; Styrene / butadiene latex base adhesives; ABA block copolymer type thermoplastic rubber (A is a thermoplastic polystyrene end block; B is a rubber intermediate block such as polyisoprene, polybutadiene or poly (ethylene / butylene)); Butyl rubber; Polyisobutylene; Acrylic adhesives such as polyacrylate and vinyl acetate / acrylic ester copolymer; And one or more selected from the group consisting of a vinyl ether copolymer such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, and the like, and may be used. As a preferred example, vinyl acetate, methyl methacrylic acid, ethyl aceto At least one selected from the group consisting of acrylates and sulfonated polystyrenes, but is not limited thereto. In the present invention, the pressure-sensitive adhesive layer 30 serves to prevent the sheet from being separated from the application position during the assembly process and use of the product, for this purpose, the peeling strength from the support film layer of the pressure-sensitive adhesive layer has passed a predetermined time. It is preferred that it will not be separated later, for example at least 200 gr / cm.

In addition, when applied to the mobile display assembly, in order to ensure the durability of the product, the pressure-sensitive adhesive layer may be used that possesses the adhesive strength of 500 gr / inch or more and heat resistance of 60 ℃ or more.

The pressure-sensitive adhesive layer 30 is obtained by applying the pressure-sensitive adhesive as described above on one surface of a transparent or white plastic support film base such as PET or PEN. That is, the coating method may be any method conventionally available in the art, for example, but may be a method such as gravure, micro gravure, comma, die, dip coating, but is not limited thereto. The thickness of the pressure-sensitive adhesive layer formed on one side of the support film layer 10 is preferably 5 μm or more in order to exhibit proper adhesive force, and the pressure-sensitive adhesive is pushed to the side during Thompson processing due to the thickness of the final product being too thick and the pressure of the excessive adhesive. In order to prevent contamination of the product and the processing machine, it is better to set it to 150 μm or less.

The shock absorbing and sealing sheet of the present invention may be a release film or a release paper is further laminated on the pressure-sensitive adhesive layer to form a release film or a release paper layer. The release film or the release paper layer may be a transparent or white plastic film, specifically, at least one selected from the group consisting of polyethylene (PE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and the like. However, it is not limited to this. At this time, the thickness of the release film layer or the release paper layer is preferably 5 μm to 125 μm. If the thickness of the release film layer or the release paper layer is too thin, it is difficult to remove the release film at the end of use, and if it is too thick, the release film or the release paper having the predetermined level of thickness is used because it affects the thickness of the entire product. good. In addition, the peel strength of the release film layer or the release paper layer from the pressure-sensitive adhesive layer is preferably at least 5 gr / cm. If the release strength of the release paper layer is too low, the release paper layer is separated from the pressure-sensitive adhesive layer during product molding, making it difficult to mold and move the product. If the release strength is too high, it is difficult to remove the release film layer at the end of use. It is good to keep.

The shock absorbing and sealing sheet of the present invention includes a shock absorbing foam layer coated with a shock absorbing foam on one surface and the other surface on which the pressure-sensitive adhesive layer of the support film layer is formed. The thickness of the coated foam layer is preferably 0.05mm or more in order to maintain a minimum shock absorption effect, and maintains the sealing effect even on the surface of the uneven electronic equipment, and prevents the final thickness from becoming too thick, the light thin end It should be less than 10mm to be able to extinguish.

The shock absorbing foam used in the present invention may be a polyurethane foam, and if necessary, antistatic treatment (ESD treatment) may be performed. The polyurethane foam is formed by the reaction of the polyol and polyisocyanate may have a specific gravity of 3 gr / cm ³ to 90 gr / cm ³ . The polyol may be one or more selected from the group consisting of polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyester polyols, caprolactone polyols, and the like. In addition, as an isocyanate which is a unit of the said polyisocyanate, methylene diphenyl diisocyanate, polymeric methylene diphenyl diisocyanate, modified methylene diphenyl diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, the said isocyanate of Carbodiimide modified bodies, dimers of the isocyanates, trimers of the isocyanates, prepolymers by reaction of the isocyanates with polyols, and the like, may be used.

A catalyst is usually used for the reaction of the polyol and polyisocyanate, and in this case, metal catalysts such as dibutyl tin dirorate, tetrabutyl titanate and red laurate, amines such as trimethylamine, triethylamine, and triethanolamine At least one selected from the group consisting of system catalysts and the like can be used. In order to foam the foam, it is possible to foam with a fluorine-based foaming agent, a chlorine-based foaming agent, a hydrocarbon-based foaming agent and an inert gas, foaming with water, and the like, and a small amount of silicon foam stabilizer can be used. Various additives such as polyol, polyisocyanate and catalyst as raw materials are uniformly mixed in an oak mixer or the like and then applied onto the support film layer. Polyurethane foam material applied to a constant thickness in the thickness range is then put into an oven which is designed continuously to be cured at a temperature of 120 ℃ or more to form a foam of a constant thickness.

At this time, it is preferable that the polyurethane foam used in the present invention has the following physical properties. First of all, it should have an appropriate impact absorbing force, and the repulsive force should be 15 to 50 in the ballistic test according to ASTM D3574. In addition, the shock-absorbing and sealing sheet of the present invention is applied to the product to be assembled in a slightly compressed state for sealing performance when assembling, when the compressive strength of the foam is too large, causing mechanical damage to the applied device, When assembling a large force is required, the efficiency of assembly work is reduced. Therefore, the compressive strength of the foam is required not to exceed an appropriate level and it is preferable to have a compressive strength of 5 kgf / cm ² or less, preferably 0.01 to 5 kgf / cm ² at 25% compression. In addition, in order to prevent the sheet from deforming even after a long time after being applied to the device, it is preferable that the permanent compressive strain is 0.5 to 10%, elongation is preferably 100% or more in order to be able to adhere to the device sufficiently. . In addition, the Shore A hardness is preferably 5 or more in order to prevent the mechanical properties from being excessively degraded, and in order to prevent excessively strong force from being applied to the electronics at the time of assembly so as to exhibit sufficient shock absorption performance. It is good that it is 80 or less. In addition, the tensile strength is preferably 2 to 3 kgf / cm ² for the same reason as in the hardness.

The present invention is basically not only excellent in the ability to prevent damage to the components due to the external impact of the electronic device, to prevent the introduction of contaminants such as dust from the outside, by minimizing the specific gravity of the unnecessary incompressible material layer, It has a relatively high polyurethane thickness ratio on the same thickness, it can provide a shock absorbing and silyl sheet having a high compression ratio, high impact absorption and excellent sealing function compared to the product laminated the existing double-sided tape. In addition, according to the sheet manufacturing method of the present invention, since the double-sided tape lamination process can be omitted, there is an advantage that the production process can be simplified, as well as to reduce the loss and failure rate of product raw materials.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, these examples are only for illustrating the present invention, and the scope of the present invention is not limited by these examples.

[Example]

Example 1 Preparation of Adhesive Substrate

HIDENOL SA-330A (Hansung Polymer) was coated on a 50 μm thick PET using a comma coater to a thickness of about 50 μm. The coated film was dried in an oven set at 120-140 ° C. for 5 minutes, dried immediately, after being laminated with a silicone treated release PET film and wound up in roll form.

Example 2: Preparation of Sheet with Shock Absorption Function

After mixing the components except the isonate 143L of the components in Table 2 in the composition ratio shown in advance and then mixing again using isonate 143L and Oaks mixer, using a comma coater on the PET film of the pressure-sensitive adhesive substrate obtained in Example 1 To 0.5 mm, 1 mm, and 2 mm thicknesses, respectively. The coated raw material was cured by staying in an oven set at 130 to 160 ° C. for 12 minutes, and continuously produced and wound up in roll form immediately after production.

 TABLE 2

Raw material Parts by weight YUKOL 3553 (polyethylene glycol, SKC company make) 100 Dipropylene glycol 15 Calcium carbonate 110 Niax L-5309 (Surfactant, manufactured by GE silicone) 0.5 Stannous octoate 0.005 Isonate 143L (Modified MDI, product made by Dow) 47

Example 3: Properties of the Sheet Having a Shock Absorbing Function

The sheet having the light shielding and shock absorbing functions completed in Example 2 has the following characteristics.

[Table 3]

Bollibound 25% compressive strength adhesiveness Adhesive Heat Resistance 0.5 mm thick 20% 0.07 kgf / cm2 1.3 kg / inch 1mm 1.0 mm thick 21% 0.11 kgf / cm2 1.3 kg / inch 1mm 2.0 mm thick 21% 0.11 kgf / cm2 1.3kg / inch 2 mm How to measure ASTM D3574 ASTM D3574 ASTM D2314 See note

Note) Adhesive heat resistance: After bonding to stainless steel specimens, measure the distance the sheet moved after storage at 85 degrees for one week after applying 500 gr / inch of load.

1 shows a manufacturing and processing process of a conventional shock absorbing sheet in order.

Figure 2 shows in order the manufacturing and processing of the shock absorbing sheet including the pressure-sensitive adhesive of the present invention.

3 shows a cross-sectional structure of a conventional shock absorbing sheet.

Figure 4 shows a cross-sectional structure of a shock-absorbing sheet in which a double-sided tape is laminated to a conventional shock-absorbing sheet.

Figure 5 shows a cross-sectional structure of the shock absorbing sheet including the pressure-sensitive adhesive layer of the present invention.

<Description of Drawing>

10: support film layer

20: polyurethane layer

30: adhesive layer

40: release film layer

Claims (20)

delete delete delete delete delete delete delete delete delete delete delete delete delete Forming an adhesive layer on one surface of the supporting film layer by applying one or more adhesives selected from the group consisting of vinyl acetate, methylmethacrylic acid, ethyl acetoacrylate and sulfonated polystyrene; Forming a release film layer or a release paper layer by laminating a release film or release paper on the pressure-sensitive adhesive layer; And Coating a polyurethane foam having a specific gravity of 3 to 90 gr / cm 3 on one surface of the support film layer on which the pressure-sensitive adhesive layer is formed, and curing the coated foam to form a shock-absorbing foam layer, The support film layer has a thickness of 5 ㎛ to 125 ㎛, The pressure-sensitive adhesive layer has a thickness of 5 ㎛ to 150 ㎛ and the peel strength from the supporting film is 200 gr / cm or more, The foam layer has a thickness of 0.05 mm to 10 mm and has a repulsive force of 15 to 50% in the ballistic test according to ASTM D3574 and a compressive strength of 0.01 to 5 kgf / cm 2 at 25% compression. Manufacturing method. delete Coating a polyurethane foam having a specific gravity of 3 to 90 gr / cm 3 on one surface of the support film layer and curing the coated foam raw material to form a shock absorbing foam layer; The pressure-sensitive adhesive layer is formed by applying one or more pressure-sensitive adhesives selected from the group consisting of vinyl acetate, methyl methacrylic acid, ethyl acetoacrylate and sulfonated polystyrene to the other surface of the support film layer on which the impact-absorbing foam layer is formed. Forming; And Forming a release film layer or a release paper layer by laminating the release film or release paper on the pressure-sensitive adhesive layer, The support film layer has a thickness of 5 ㎛ to 125 ㎛, The foam layer has a thickness of 0.05 mm to 10 mm and has a repulsive force of 15 to 50% in the ballistic test according to ASTM D3574 and a compressive strength of 0.01 to 5 kgf / cm 2 at 25% compression, The pressure-sensitive adhesive layer has a thickness of 5 ㎛ to 150 ㎛ and the peel strength from the support film 200 gr / cm or more of the method for producing a shock absorbing and sealing sheet. delete The method according to claim 14 or 16, The support film layer is polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester, polyamide, polycarbonate, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-propylene copolymer, and At least one selected from the group consisting of polyvinyl chloride. delete delete

Images