KR101989614B1 - Impact-absorbing adhesive tape having improved durability in an environment with a high temperature and a high humidity - Google Patents

Abstract

The disclosed shock absorbing adhesive tape includes an impact resistant foam structure comprising expanded impact resistant particles and crosslinked binder resin bonded to the impact resistant particles and an adhesive layer bonded to at least one side of the impact resistant foam structure. The crosslinked binder resin is formed by crosslinking of acrylic binder resin. The acrylic binder resin may include 15 wt% to 35 wt% of ethyl acrylate (EA), 15 wt% to 35 wt% of methyl methacrylate (MMA), and n-butyl acrylate (n-butyl). acrylate, n-BA) 15% to 30% by weight, 10% to 20% by weight of methoxy polyethylene glycol methacrylate (MPEGMA) and 1% to 5% by weight of acrylamide It is formed by the addition reaction of the monomer mixture containing, and has a glass transition temperature of -50 ° C to 10 ° C.

Description

IMPACT-ABSORBING ADHESIVE TAPE HAVING IMPROVED DURABILITY IN AN ENVIRONMENT WITH A HIGH TEMPERATURE AND A HIGH HUMIDITY}

The present invention relates to a shock absorbing adhesive tape and a method for producing the same. More specifically, the present invention relates to a shock absorbing adhesive tape having an impact resistant foam structure and a method of manufacturing the same.

Recently, in electronic devices such as mobile phones, displays, and touch screen panels (TSPs), adhesive tapes including a pressure sensitive adhesive (PSA) have been used for bonding or laminating components.

When the adhesive tape is used in the electronic device, physical properties for absorbing external shocks with improved adhesion are required. Accordingly, efforts have been made to optimize the composition and structure of the adhesive layer included in the adhesive tape to improve the impact resistance of the adhesive tape.

However, a problem may occur in that the durability of the adhesive tape is lowered due to use environment, for example, heat generation of the electronic device to which the adhesive tape is attached.

One object of the present invention is to provide an impact absorbing adhesive tape having excellent mechanical reliability and having high durability in a high temperature / high humidity environment.

One object of the present invention is to provide a method for producing the shock absorbing adhesive tape.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, and may be variously expanded within a range without departing from the spirit and scope of the present invention.

Shock-absorbing adhesive tape according to exemplary embodiments of the present invention for achieving the above object of the present invention, the impact-resistant foam structure including the impact particles expanded foam particles and the crosslinked binder resin bonded to the impact particles And an adhesive layer bonded to at least one surface of the impact resistant foam structure. The crosslinked binder resin is formed by crosslinking of acrylic binder resin. The acrylic binder resin may include 15 wt% to 35 wt% of ethyl acrylate (EA), 15 wt% to 35 wt% of methyl methacrylate (MMA), and n-butyl acrylate (n-butyl). acrylate, n-BA) 15% to 30% by weight, 10% to 20% by weight of methoxy polyethylene glycol methacrylate (MPEGMA) and 1% to 5% by weight of acrylamide It is formed by the addition reaction of the monomer mixture containing, and has a glass transition temperature of -50 ° C to 10 ° C.

According to one embodiment, the monomer mixture further comprises 1% to 3% by weight of styrene.

According to one embodiment, the monomer mixture, 20% to 25% by weight of ethyl acrylate, 25% to 30% by weight of methyl methacrylate, 15% to 25% by weight of n-butyl acrylate, methoxypolyethylene 10 wt% to 20 wt% of glycol methacrylate, 1 wt% to 5 wt% of acrylamide, and 1 wt% to 3 wt% of styrene, and the glass transition temperature of the acrylic binder resin is -20 ° C to 0 ° C. .

According to one embodiment, the pressure-sensitive adhesive layer includes an acrylic pressure-sensitive adhesive.

According to one embodiment, the shock-absorbing adhesive tape further includes an embossed release sheet attached to the adhesive layer. The embossed release sheet has an embossed pattern formed on an attachment surface bonded to the adhesive layer, and the embossed pattern has protrusions extending along a direction perpendicular to each other on a plan view.

According to one embodiment, in the embossed sheet, the height of the protrusions is 5 to 10 μm, the width of the protrusions is 15 to 30 μm, and the distance between adjacent protrusions is 130 to 180 μm.

Method for producing a shock-absorbing adhesive tape according to an exemplary embodiment of the present invention, applying a foam composition comprising an acrylic binder resin, pre-expanded particles, a curing agent and a solvent on a substrate, onto the applied foam composition Forming a preliminary foam by performing a preliminary heat treatment, converting the preliminary foam into an impact resistant foam structure including the impact resistant particles in which the preliminary foam particles are expanded through heat treatment, and an adhesive layer on at least one surface of the impact resistant foam structure Forming a step.

According to exemplary embodiments of the present invention as described above, according to the present invention, after forming a preliminary foam from a foam composition comprising pre-expanded particles, the pre-expanded foam to expand the pre-expanded particles, including impact-resistant foam The structure may be formed, and after pre-expanding or pre-expansion, the pre-expanded particles are mixed with the binder composition in advance to form the preliminary foam, and then a foaming process or an expansion process may be performed. Therefore, mechanical properties such as bonding strength between the impact resistant particles and the binder layer are improved, and the impact resistance of the impact resistant particles may also be stably maintained.

In addition, through the combination of the monomers constituting the acrylic binder resin of the foam composition, not only can improve the shock absorption performance, but also increase the bonding strength with the adhesive layer in a high temperature / high humidity environment, thereby improving the reliability of the adhesive tape Can be.

1 is a flowchart illustrating a method of manufacturing an impact absorbing adhesive tape according to an embodiment of the present invention.
2 to 4 are cross-sectional views illustrating a method of manufacturing an impact absorbing adhesive tape according to an embodiment of the present invention.
5 is a cross-sectional view showing an adhesive tape according to another embodiment of the present invention.
6 is a cross-sectional view showing an adhesive tape according to another embodiment of the present invention.
7A is an enlarged cross-sectional view of an embossed adhesive layer and an embossed release sheet of the adhesive tape of FIG. 6.
FIG. 7B is a plan view partially showing the embossed adhesive layer of FIG. 6.
8A and 8B are cross-sectional views illustrating a process of attaching an adhesive tape having an embossed adhesive layer according to an embodiment of the present invention.
9 is a graph showing a stress-strain curve of the impact resistant foam structure obtained using the acrylic copolymer (indicated by the glass transition temperature) obtained in Synthesis Examples 1 to 4. FIG.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. As the inventive concept allows for various changes and numerous modifications, particular embodiments will be illustrated and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, or a combination thereof described in the specification, but one or more other features or numbers. It is to be understood that the present invention does not exclude in advance the possibility of the presence or the addition of steps, actions, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

1 is a flowchart illustrating a method of manufacturing an impact absorbing adhesive tape according to an embodiment of the present invention. 2 to 4 are cross-sectional views illustrating a method of manufacturing an impact absorbing adhesive tape according to an embodiment of the present invention.

Referring to FIG. 1, for example, in step S12, a foaming composition may be prepared.

The foaming composition may include pre-expanded particles (eg, denoted by reference numeral 120 of FIG. 2), an acryl-based binder resin, a curing agent, and a solvent.

According to one embodiment, the pre-expanded particles may have a microsphere form. For example, the pre-expanded particles can have a microsphere shape in the range of about 5 micrometers (μm) to about 15 μm.

As shown in FIG. 2, the pre-expanded particles may include a foamed seed 123 and an elastic shell 125 that coats the foamed seed 123 surface.

According to an embodiment, the foamed seed 123 may include a hydrocarbon-based material such as butane or pentane. In one embodiment, the foamed seed 123 may include the hydrocarbon-based material in a liquid phase. Elastic shell 125 may comprise a polymeric material such as, for example, an acrylonitrile copolymer.

According to one embodiment, the pre-expanded particles 120 may consist substantially of the foamed seed 123 and the elastic shell 125. In this case, for example, an additional coating layer including an inorganic material such as calcium carbonate may not be formed on the surface of the elastic shell 125. Accordingly, problems such as cracking or poor expansion of the inorganic material may be prevented by a subsequent foaming process or an expansion process.

The acrylic binder resin is obtained by addition polymerization of monomers. The monomer mixture forming the acrylic resin may include ethyl acrylate (EA), methyl methacrylate (MMA), n-butyl acrylate (n-BA), and methoxy polyethylene. Glycol methacrylate (MPEGMA) and acrylamide.

The ethyl acrylate increases the softness of the foam structure formed from the foam composition, thereby increasing the shock absorbing performance at room temperature. However, when the content of the ethyl acrylate is excessive, the foam structure reliability at high temperature may be lowered. For example, the content of the ethyl acrylate is preferably 15% to 35% by weight of the total weight of the monomer mixture.

The methyl methacrylate can increase the hardness of the foam structure, thereby increasing the foam structure reliability at high temperatures. However, when the content of the methyl methacrylate is excessive, the shock absorbing performance of the foam structure may be lowered. For example, the content of the methyl methacrylate is preferably 15% to 35% by weight of the total weight of the monomer mixture.

The n-butyl acrylate may increase the flexibility of the foam structure, and increase the binding force between the binder and the foam. However, when the content of the n-butyl acrylate is excessive, high temperature adhesion of the foam structure and the adhesive layer may be lowered. For example, the content of n-butyl acrylate is preferably 15% to 30% by weight of the total weight of the monomer mixture.

The methoxy polyethylene glycol methacrylate, may increase the resilience and restoring force to the impact of the foam structure. However, when the content of the methoxy polyethylene glycol methacrylate is excessive, the impact absorption performance of the foam structure and the bonding force with the adhesive layer at room temperature may be lowered. For example, the content of the methoxy polyethylene glycol methacrylate is preferably 10% to 20% by weight of the total weight of the monomer mixture. The methoxy polyethylene glycol methacrylate is a polymer monomer, when the molecular weight is excessively large, the high temperature adhesion of the foam structure and the adhesive layer may be lowered, if less than, the shock absorption performance of the foam structure and at room temperature Adhesion with the adhesive layer may be lowered. Preferably, the weight average molecular weight of the methoxy polyethylene glycol methacrylate may be about 30,000 to 50,000.

The acrylamide may increase the elasticity of the foam structure, but when the content is excessive, the impact absorption performance and adhesion at room temperature of the foam structure may be reduced. For example, the content of acrylamide is preferably 1% to 5% by weight of the total weight of the monomer mixture.

According to one embodiment, the monomer mixture may further comprise styrene (styrene). The styrene may increase the high temperature / high humidity reliability of the foam structure, but when the content is excessive, the impact absorption performance of the foam structure and the bonding force with the adhesive layer at room temperature may be reduced. For example, the content of the styrene is preferably 1% to 3% by weight of the total weight of the monomer mixture.

Thus, according to one embodiment, the monomer mixture, 15% to 35% by weight of ethyl acrylate, 15% to 35% by weight of methyl methacrylate, 15% to 30% by weight of n-butyl acrylate, meth 10 wt% to 20 wt% of oxypolyethylene glycol methacrylate, 1 wt% to 5 wt% of acrylamide, and 1 wt% to 3 wt% of styrene.

The molecular weight of the acrylic binder resin may be controlled by polymerization temperature and reaction time. For example, the weight average molecular weight of the acrylic binder resin is preferably 200,000 to 300,000. When the weight average molecular weight of the acrylic binder resin exceeds 200,000, the viscosity is excessively increased, the processability is lowered, if less than 300,000, mechanical properties may be lowered.

For example, the acrylic binder resin may have a glass transition temperature of about -50 ° C to 10 ° C, depending on the composition. When the glass transition temperature of the acrylic binder resin is excessively low, the compressive load is reduced, the restoring force may be lowered, and the high temperature adhesion with the adhesive layer may be lowered. If the glass binder is excessively high, the shock absorption performance is lowered, At room temperature adhesion may be lowered. Preferably, the glass transition temperature of the acrylic binder resin may be -30 ℃ to 0 ℃, more preferably, may be -20 ℃ to 0 ℃. For example, the monomer mixture for obtaining a glass transition temperature of -20 ° C to 0 ° C, 20% to 30% by weight of ethyl acrylate, 25% to 30% by weight of methyl methacrylate, n-butyl acryl 15 wt% to 25 wt%, 10 wt% to 20 wt% methoxypolyethylene glycol methacrylate, 1 wt% to 5 wt% acrylamide, and 1 wt% to 3 wt% styrene.

An epoxy compound, a melamine compound, an isocyanate compound, a metal salt, or an amine compound may be used as the curing agent. These may be used alone or in combination of two or more. In one embodiment, an isocyanate compound may be used as the curing agent.

The solvent may be an organic solvent such as toluene, methyl ethyl ketone (MEK), ethyl acrylate (EA) and the like. The foaming composition may be adjusted to have a suitable viscosity by the solvent, for example, the foaming composition may have a viscosity of about 1,600 cps to about 2,400 cps.

According to one embodiment, the foaming composition is based on 100 parts by weight of the acrylic binder resin, 1 part by weight to 3 parts by weight of the pre-expanded particles, 0.5 parts by weight to 5 parts by weight of the curing agent and 20 parts by weight to 30 parts by weight of the solvent It may include wealth.

According to one embodiment, the foaming composition may further include a pigment material such as carbon black, graphite powder. For example, the pigment may be mixed in an amount of 1 part by weight to 5 parts by weight based on 100 parts by weight of the acrylic binder resin.

In addition, the foam composition may further include additional components for improving the mechanical and physical reliability of the preform 110 and / or the impact resistant foam structure 140, such as a silane coupling agent, an antifoaming agent, and the like.

For example, the foaming composition may be obtained by mixing the pre-expanded particles and the binder. For example, the foaming composition may be obtained by preparing a binder composition including the binder, the curing agent, the solvent, and the like, and preliminarily adding the pre-expanded particles to the binder composition to stir slowly.

1 and 2, for example, the foaming composition may be applied to the substrate in step S14. Thereafter, for example, a preliminary heat treatment may be performed on the foam composition applied in step S16 to form a preliminary foam 110.

As shown in FIG. 2, the pre-expanded particles 120 may include a foamed seed 123 and an elastic shell 125, according to one embodiment, to the foamed seed 123 and the elastic shell 125. Can be configured. In one embodiment, the pre-expanded particles 120 may not include an inorganic material.

The substrate 100 may be, for example, a polymer film including a polymer such as polyester-based, polycarbonate-based, polyimide-based, or the like such as (polyethylene terephthalate: PET).

According to exemplary embodiments, the preliminary heat treatment may be performed at a temperature lower than the expansion start temperature of the foamed seed 123 included in the pre-expanded particles 120. For example, the preliminary heat treatment may be performed at a temperature in the range of about 40 ℃ to about 100 ℃. According to an embodiment, the preliminary heat treatment may be performed by dividing into a plurality of temperature sections.

For example, the thickness of the preform 110 may be adjusted to range from about 20 μm to about 50 μm.

1 and 3, for example, in step S18, the preliminary foam particles 120 may be expanded through heat treatment to convert the preliminary foam 110 into an impact resistant foam structure 140.

According to exemplary embodiments, the heat treatment may be performed at a temperature range between the expansion start temperature and the maximum expansion temperature of the foamed seed 123.

According to one embodiment, the expansion initiation temperature may range from about 110 ° C. to about 130 ° C., and the maximum expansion temperature may range from about 130 ° C. to about 190 ° C. According to one embodiment, the maximum expansion temperature may range from about 130 ° C to about 165 ° C.

In some exemplary embodiments, the heat treatment may be performed at a temperature in the range of about 110 ° C to about 180 ° C. According to one embodiment, the heat treatment may be performed at a temperature in the range of about 130 ℃ to about 160 ℃. According to one embodiment, the heat treatment may be performed divided into a plurality of temperature intervals.

The pre-expanded particles 120 may be converted into impact resistant particles 130 by the heat treatment. The impact resistant particle 130 may include a hollow portion 133 formed by expanding or expanding the foamed seed 123 and an expanded elastic shell 135 formed by expanding the elastic shell 125. In addition, in the heat treatment process, the acrylic binder resin may be cured to form a crosslinked structure that surrounds the impact resistant particles 130 and is bonded thereto.

Impact-resistant particles 130 may be expanded by about 1.2 times to about 5 times the diameter of the pre-expanded particles (120). In addition, the thickness of the impact resistant foam structure 140 may also be increased by about 1.2 times to about 5 times the thickness of the initial preform 110. According to one embodiment, the diameter of the impact resistant particles 130 and the thickness of the impact resistant foam structure 140 may be expanded about 2 times to about 5 times. For example, the impact resistant foam structure 140 may be expanded to a thickness of about 50 μm to about 200 μm.

As described above, the preliminary heat treatment and heat treatment process may be divided into a plurality of temperature intervals, respectively, for example, the substrate 100 on which the preliminary foam 110 shown in FIG. The foaming process may be performed while sequentially passing through a plurality of chambers on a furnace conveyor.

According to one embodiment, some of the chambers may have an internal temperature set to a temperature lower than the expansion start temperature of the foamed seed 123, and the other part may be a temperature between the expansion start temperature and the maximum expansion temperature. Internal temperature can be set. In addition, each of the chambers may be set such that the internal temperature is sequentially increased along the moving direction of the conveyor.

According to the exemplary embodiments as described above, the bonding strength with the pre-expanded particles 120 can be improved while pre-curing the binder resin of the pre-form 110 through pre-heating before the foaming or expansion start. In addition, structural defects such as cracks and voids of the binder layer and impact-resistant particles 130 due to rapid foaming or expansion may be prevented.

In addition, the foaming or expansion process can also be performed through the chamber divided according to the temperature to improve the foaming stability for the impact-resistant particles 130 formed.

1 and 4, for example, in step S22, the adhesive layer 150 is formed on one surface of the impact resistant foam structure 140. The adhesive layer 150 may be formed on another surface to which the substrate 100 is not attached.

For example, the adhesive layer 150 may be formed by applying a pressure sensitive adhesive (PSA). As the pressure-sensitive adhesive, those known in the art may be used. For example, the pressure-sensitive adhesive may be an acrylic adhesive, and specifically, may include a pressure-sensitive adhesive including an acrylic copolymer-based material. More specifically, the pressure-sensitive adhesive may include an acrylic copolymer, a crosslinking agent and a solvent. The crosslinking agent may include an epoxy-based compound, a melamine-based compound, an isocyanate compound, and the like. The solvent may include acetone, toluene, methyl ethyl ketone and the like.

For example, the pressure-sensitive adhesive may be cured to form an adhesive layer 150 including a crosslinked structure of the acrylic resin.

According to one embodiment, the substrate 100 on which the impact resistant foam structure 140 is formed may be aged. According to one embodiment, the impact resistant foam structure 140 is aged at a temperature lower than the expansion initiation temperature, for example, in a range of about 110 ° C. to about 180 ° C. to stabilize the expansion structure of the impact resistant particles 130. You can. By the aging process, the shape of the hollow part 133 and the expandable elastic shell 135 may be maintained as it is.

The aging step, after forming the adhesive layer 150, or before forming the adhesive layer 150, all possible, but proceeds after forming the adhesive layer 150, the adhesive layer ( 150) and may be advantageous to increase the bonding strength of the impact resistant foam structure 140.

Although not shown, a release sheet may be coupled to one surface of the adhesive layer 150. In addition, the base material 100 may be separated from the impact resistant foam structure 140, but the present invention is not limited thereto, and the base material 100 and the impact resistant foam structure 140 are bonded to each other with an adhesive tape. May be used.

According to the present invention, after forming the preliminary foam from the foaming composition including the preliminary expanded particles, the preliminary expanded particles may be expanded to form an impact resistant foam structure including the impact resistant particles, and the prefoamed particles before or before expansion After mixing with the binder composition in advance to form in the form of the preform, the foaming process or expansion process may be performed. Therefore, mechanical properties such as bonding strength between the impact resistant particles and the binder layer are improved, and the impact resistance of the impact resistant particles may also be stably maintained.

In addition, through the combination of the monomers constituting the acrylic binder resin of the foam composition, not only can improve the shock absorption performance, but also increase the bonding strength with the adhesive layer in a high temperature / high humidity environment, thereby improving the reliability of the adhesive tape Can be.

The adhesive tape according to the present invention may have various configurations including an impact resistant foam structure and an adhesive layer.

5 is a cross-sectional view showing an adhesive tape according to another embodiment of the present invention.

Referring to Figure 5, the adhesive tape according to an embodiment of the present invention, the impact-resistant foam structure 140, including the impact-resistant particles 130 dispersed in the cross-linked structure of the acrylic binder, the agent of the impact-resistant foam structure 140 The first adhesive layer 150a attached to one surface, the second adhesive layer 150b attached to the second surface of the impact resistant foam structure, and the first release sheet 102a bonded to the first adhesive layer 150a. And a second release sheet 102b coupled to the second adhesive layer 150b. The impact resistant foam structure 140, the first adhesive layer 150a, and the second adhesive layer 150b may be combined with each other. ) May have the same configuration as the impact resistant foam structure and the adhesive layer described above. In addition, the first release sheet 102a and the second release sheet 102b may be a polymer film including a polymer such as polyethylene terephthalate, polycarbonate, or the like.

According to the embodiment, by placing the impact-resistant foam structure 140 including the impact-resistant particles 130 between the adhesive layers (150a, 150b), it is possible to provide a stable impact resistance without weakening the adhesion, double-sided adhesion Can be used as a tape

6 is a cross-sectional view showing an adhesive tape according to another embodiment of the present invention. 7A is an enlarged cross-sectional view of an embossed adhesive layer and an embossed release sheet of the adhesive tape of FIG. 6. FIG. 7B is a plan view partially showing the embossed adhesive layer of FIG. 6.

6, the pressure-sensitive adhesive tape according to an embodiment of the present invention, an impact resistant foam structure 140 including impact resistant particles 130 dispersed in a crosslinked structure of an acrylic binder, one surface of the impact resistant foam structure 140 It may include an embossed adhesive layer 152 attached to the embossed release sheet 160 coupled to the embossed adhesive layer 152.

The embossed release sheet 160 has an embossed pattern formed on an attachment surface bonded to the embossed adhesive layer 152. Therefore, an embossed pattern corresponding to the reverse of the embossed pattern of the embossed release sheet 160 is formed on the embossed adhesive layer 152.

For example, the embossed sheet 160 may have protrusions extending along a first direction D1 and a second direction D2 perpendicular to the first direction D1 on a plan view. The height H1 of the protrusion may be about 5 to 10 μm, and the width W1 of the protrusion may be about 15 to 30 μm. In addition, the distance between adjacent protrusions along the first direction D1 or the second direction D2 may be about 130 to 180 μm.

The embossed adhesive layer 152 may have an embossed pattern corresponding to the inverse of the embossed pattern of the embossed release sheet 160. Therefore, it may have a channel 154 corresponding to the protrusion of the embossed sheet 160. Through the channel 154, a discharge passage of bubbles that may be generated during the adhesive tape manufacturing process may be provided.

In addition, the embossed adhesive layer 152 may have a high profile reliability within the numerical range. Therefore, when provided in a display device or the like, the shock absorbing performance and reliability thereof of the adhesive tape can be improved.

For example, as illustrated in FIGS. 8A and 8B, after removing the embossed sheet 160, the embossed adhesive layer 152 may be bonded to the display device 200. The display device 200 may include a liquid crystal display, an organic light emitting display, or the like, and may be improved in impact resistance by a thin adhesive tape.

For example, the embossed adhesive layer 152 may be formed of the acrylic adhesive described above.

Hereinafter, the characteristics of the impact resistant foam structure according to the exemplary embodiments will be described in more detail with reference to specific experimental examples.

Experimental Example

Synthesis Example 1

Ethyl acrylate about 30% by weight, methyl methacrylate about 20% by weight, n-butyl acrylate about 30% by weight, methoxypolyethylene glycol methacrylate (weight average molecular weight: about 40,000) about 15% by weight, acrylamide about 3% by weight and about 2% by weight of styrene were mixed, using azo-bis-isobutyrylnitrile (AIBN) as an initiator (about 0.002 parts by weight relative to 100 parts by weight of the mixture), at about 40 ° C. for about 1 hour, The reaction was carried out at about 55 ° C. for about 6 hours to obtain an acrylic copolymer having a glass transition temperature of about −30 ° C.

Synthesis Example 2

About 30% ethyl acrylate, about 25% methyl methacrylate, about 25% n-butyl acrylate, about 15% methoxypolyethylene glycol methacrylate, about 3% acrylamide and about 2% styrene % Is mixed and reacted with azo-bis-isobutyrylnitrile (AIBN) as an initiator (about 0.002 parts by weight based on 100 parts by weight of the mixture) at about 40 ° C for about 1 hour and at about 55 ° C for about 6 hours It proceeded and the acrylic copolymer whose glass transition temperature is about -20 degreeC was obtained.

Synthesis Example 3

About 30% ethyl acrylate, about 30% methyl methacrylate, about 20% n-butyl acrylate, about 15% methoxypolyethylene glycol methacrylate, about 3% acrylamide and about 2% styrene % Is mixed and reacted with azo-bis-isobutyrylnitrile (AIBN) as an initiator (about 0.002 parts by weight based on 100 parts by weight of the mixture) at about 40 ° C for about 1 hour and at about 55 ° C for about 6 hours It proceeded and the acrylic copolymer whose glass transition temperature is about -10 degreeC was obtained.

Synthesis Example 4

About 25% ethyl acrylate, about 35% methyl methacrylate, about 20% n-butyl acrylate, about 15% methoxypolyethylene glycol methacrylate, about 3% acrylamide and about 2% styrene % Is mixed and reacted with azo-bis-isobutyrylnitrile (AIBN) as an initiator (about 0.002 parts by weight based on 100 parts by weight of the mixture) at about 40 ° C for about 1 hour and at about 55 ° C for about 6 hours It proceeded and the acrylic copolymer whose glass transition temperature is about 0 degreeC was obtained.

Example

For each 100 parts by weight of the acrylic copolymers of Synthesis Examples 1 to 4, 2.6 parts by weight of isocyanate curing agent, 3 parts by weight of black pigment, 0.5 part by weight of silane coupling agent (product name: KBM-403) and antifoaming agent (product name: BYK-333 ) 0.5 parts by weight and 25 parts by weight of toluene were mixed to prepare a foaming composition, and 2 parts by weight of the pre-expanded particles were mixed with the foaming composition with agitation to prepare a foaming composition.

After applying the foam composition on the PET substrate to form a preform, using a foam line of the temperature conditions shown in Table 1 was carried out a pre-heat treatment and heat treatment process while moving the preform at a speed of 12m / min. Accordingly, an impact resistant foam structure including impact resistant particles was obtained, and then a aging process was performed for 48 hours at a temperature of 60 ° C.

Table 1

9 is a graph showing a stress-strain curve of the impact resistant foam structure obtained using the acrylic copolymer (indicated by the glass transition temperature) obtained in Synthesis Examples 1 to 4. FIG. 9, it can be seen that as the glass transition temperature of the acrylic copolymer increases, the compressive load increases.

Experiment 1  -Measurement of general physical properties

General physical properties (thickness, density, tensile strength, elongation, compressive load, impact absorption) of the impact-resistant foam structure obtained using the acrylic copolymer of Synthesis Example 3 were measured and shown in Table 2 below. In Table 1 below, MD and TD refer to the machine direction and the transverse direction, respectively, and 25% and 50% of the compressive load represent the deformation amount, respectively. It is divided by the amount of impact alone.

TABLE 2

Experiment 2-Adhesion Measurement

The impact resistant foam structure obtained using the acrylic copolymer of Synthesis Example 3 was fixed to the SUS plate, and the PI tape (SKCKOLONPI-GF100) was attached to the inner surface of the impact resistant foam structure, and then pressurized with a roller, respectively, at room temperature and 85 ° C. After leaving for 30 minutes, the adhesive force at the time of peeling (300 mm / min) was measured.

Similarly to the above, the impact resistant foam structure obtained by Example 1 was fixed to the SUS plate, and the embossed tape (SLS-BEPM040D-C) was attached to the outer surface of the impact resistant foam structure (PET release sheet), and then pressurized with a roller. After leaving for 30 minutes at room temperature and 85 ° C., respectively, the adhesion force at the time of peeling (300 mm / min) was measured. The adhesion force measurement results are shown in Table 3 below.

TABLE 3

Referring to Table 2 and Table 3, the adhesive tape according to the present invention may have excellent impact resistance properties, it can be seen that high temperature / high humidity reliability can be improved by maintaining a high adhesion even at room temperature and high temperature.

The shock-absorbing adhesive tape according to the above-described exemplary embodiments may be combined with, for example, a display device such as a mobile phone, an OLED device, or an LCD device, a TSP, or the like, to improve characteristics such as impact resistance and repulsion resistance. .

Although the above has been described with reference to the embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated.

100: base material 110: preform
120: pre-expanded particles 123: foamed seed
125: elastic shell 130: impact particles
133: hollow part 135: intumescent elastic shell
150: adhesive layer 150a: first adhesive layer
150b: second adhesive layer 152: embossed adhesive layer

Claims (13)

An impact resistant foam structure including expanded impact resistant particles and crosslinked binder resin bonded to the impact resistant particles; And
An adhesive layer bonded to at least one surface of the impact resistant foam structure,
The crosslinked binder resin is formed by crosslinking of an acrylic binder resin, and the acrylic binder resin may include 15 wt% to 35 wt% of ethyl acrylate (EA), methyl methacrylate (MMA) 15 % To 35% by weight, 15% to 30% by weight of n-butyl acrylate (n-BA), 10% to 20% by weight of methoxy polyethylene glycol methacrylate (MPEGMA) Formed by the addition reaction of a monomer mixture comprising, by weight, from 1% to 3% by weight of styrene and from 1% to 5% by weight of acrylamide, and having a glass transition temperature of -50 ° C to 10 ° C. Shock absorption adhesive tape characterized by the above-mentioned. delete According to claim 1, wherein the monomer mixture, 20% to 30% by weight of ethyl acrylate, 25% to 30% by weight of methyl methacrylate, 15% to 25% by weight of n-butyl acrylate, methoxypolyethylene 10 to 20 weight percent of glycol methacrylate, 1 to 5 weight percent of acrylamide and 1 to 3 weight percent of styrene,
The glass transition temperature of the acrylic binder resin is -20 ° C to 0 ° C shock-absorbing adhesive tape, characterized in that. The shock absorbing adhesive tape according to claim 1, wherein the adhesive layer comprises an acrylic adhesive. The method of claim 1, further comprising an embossed release sheet attached to the adhesive layer,
The embossed release sheet has an embossed pattern formed on an attachment surface bonded to the adhesive layer, wherein the embossed pattern has protrusions extending along a direction perpendicular to each other on a plan view. The shock absorbing adhesive tape according to claim 5, wherein the height of the protrusions is 5 to 10 mu m, the width of the protrusions is 15 to 30 mu m, and the distance between adjacent protrusions is 130 to 180 mu m. Applying a foaming composition comprising an acrylic binder resin, pre-expanded particles, a curing agent and a solvent on a substrate;
Performing a preliminary heat treatment on the applied foam composition to form a preform;
Converting the preliminary foam into an impact resistant foam structure comprising impact resistant particles in which the prefoamed particles are expanded through heat treatment; And
Forming an adhesive layer on at least one surface of the impact resistant foam structure,
The foaming composition, based on 100 parts by weight of the acrylic binder resin, 1 part to 3 parts by weight of the pre-expanded particles, 0.5 parts to 5 parts by weight of the curing agent and 20 parts to 30 parts by weight of the solvent,
The acrylic binder resin may include 15 wt% to 35 wt% of ethyl acrylate (EA), 15 wt% to 35 wt% of methyl methacrylate (MMA), and n-butyl acrylate (n-butyl). acrylate, n-BA) 15% to 30% by weight, 10% to 20% by weight of methoxy polyethylene glycol methacrylate (MPEGMA), 1% to 3% by weight of styrene and acrylamide A method for producing an impact-absorbing pressure-sensitive adhesive tape formed by addition reaction of a monomer mixture comprising 1% by weight to 5% by weight, and having a glass transition temperature of -50 ° C to 10 ° C. According to claim 7, wherein the monomer mixture, 20% to 25% by weight of ethyl acrylate, 25% to 30% by weight of methyl methacrylate, 20% to 30% by weight of n-butyl acrylate, methoxypolyethylene 10 to 20 weight percent of glycol methacrylate, 1 to 5 weight percent of acrylamide and 1 to 3 weight percent of styrene,
The glass transition temperature of the acrylic binder resin is -20 ℃ to 0 ℃ manufacturing method of the impact-absorbing adhesive tape, characterized in that. 8. The method of claim 7, wherein the pre-expanded particles include a foamed seed comprising a liquid hydrocarbon-based material and an elastic shell surrounding the foamed seed. 10. The method of claim 9, wherein the pre-expanded particles are composed of the foamed seed and the elastic shell and do not contain an inorganic material. 10. The method of claim 9, wherein the preliminary heat treatment is carried out at a temperature lower than the expansion start temperature of the foamed seed, the heat treatment is carried out at a temperature lower than the maximum expansion temperature of the foamed seed of the shock-absorbing adhesive tape Way. The method of claim 7, wherein the curing agent of the shock-absorbing pressure-sensitive adhesive tape, characterized in that at least one selected from epoxy-based compound, melamine-based compound, isocyanate compound, metal salt and amine-based compound Manufacturing method. The method of manufacturing a shock absorbing adhesive tape according to claim 7, further comprising, after the adhesive layer is formed, aging the impact resistant foam structure at a temperature lower than the expansion start temperature of the pre-expanded particles.

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