KR20190140892A - Double-sided adhesive tape - Google Patents

Abstract

The present invention relates to a double-sided adhesive tape, which comprises: a substrate layer; and an adhesive layer laminated on both sides of the substrate layer and, more specifically, to a double-sided adhesive tape comprising a cured product of a (meth)acrylic syrup including a (meth)acrylic polymer having an adhesive layer polydispersity index (PDI) of greater than 5 and not more than 10, and to a manufacturing method thereof.

Description

Double-sided adhesive tape {DOUBLE-SIDED ADHESIVE TAPE}

It is related with a double-sided adhesive tape.

In general, the acrylic syrup has transparency, and the cured product cured therein is easy to control adhesion to various substrates, and is used in various applications such as adhesive sheets, adhesive films, protective coatings, foams, and adhesives.

Polymerization methods for producing such acrylic syrups include, for example, solution polymerization and emulsion polymerization.

In the case of solution polymerization, the organic solvent may remain in the acrylic syrup and may cause odors, fires, explosions, and the like, and if it is removed by evaporation into the atmosphere, air pollution may be harmful to the environment.

In addition, in the case of emulsion polymerization, organic solvents are not used, but the polymers may not be used as they are, but additives such as neutralizers, wetting agents, thickeners, and fungicides should be added in a large amount. Since a large amount of water is used in the process of washing the reactor is generated a lot of waste water.

For this reason, bulk polymerization can be used for eco-friendliness, high yield, and economic efficiency. Such bulk polymerization includes thermal thermal polymerization or bulk photopolymerization initiated by light.

In the case of bulk thermal polymerization, since the reaction rate is relatively small, the productivity is smaller, and even after the temperature is lowered, the polymerization may continue to some extent at room temperature, thereby changing physical properties.

On the other hand, in the case of using the bulk photopolymerization, the reaction rate is fast, and the productivity is high, but when the light is blocked, the polymerization is no longer performed at room temperature, so the storage stability against temperature is excellent, but the reaction may occur explosively and control the reaction. There is a problem that it is difficult to uniformly prepare acrylic syrup having a desired level of conversion.

Accordingly, in the case of the adhesive tape manufactured using such an acrylic syrup, various physical properties thereof, for example, impact resistance, deformation resistance, strength and tackiness are difficult to appropriately match.

In one embodiment of the present invention, it provides a double-sided adhesive tape that can simultaneously implement excellent adhesion, excellent deformation resistance and excellent impact resistance.

In another embodiment of the present invention, there is provided a method for producing a double-sided adhesive tape that can simultaneously realize excellent adhesion, excellent deformation resistance and excellent impact resistance.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

In one embodiment of the invention, the substrate layer; And a pressure-sensitive adhesive layer laminated on both sides of the base layer, wherein the pressure-sensitive adhesive layer has a polydispersity index (PDI) of greater than 5 and less than or equal to 10 or less. It provides a double-sided adhesive tape comprising a.

The double-sided adhesive tape has excellent adhesion, excellent deformation resistance by using the adhesive layer comprising a cured product formed of a (meth) acrylic syrup having a polydispersity index of, for example, greater than 5, specifically, greater than 5 and less than 10, and Excellent impact resistance can be realized at the same time.

The adhesive layer may have an adhesive force of about 1,000 gf / in to about 4,000 gf / in. By having an adhesive force within the above range it is possible to effectively prevent the sliding or falling phenomenon by implementing excellent adhesiveness when removing from a predetermined substrate, it is possible to prevent more damage to the substrate, such as, for example, window panel of a television It is possible to more stably fix heavy parts and the like.

Impact strength of the double-sided adhesive tape may be about 720mJ to about 1,500mJ. By having an impact strength within the above range it can effectively absorb the external shock to implement excellent impact resistance, for example, is used for fixing the window panel of a mobile device such as a mobile phone, such as broken or dropped mobile It can effectively prevent damage or deterioration of equipment.

In another embodiment of the present invention, (a) a bulk polymerization is initiated by irradiation of light to a composition comprising a (meth) acrylic monomer and a photoinitiator, and from 5 ° C. to the temperature of the composition at the time when the bulk polymerization is initiated. Stopping the bulk polymerization at a time point of 50 ° C. increase; (b) further mixing the chain transfer agent and the photoinitiator with the composition after stopping the bulk polymerization; (c) the bulk polymerization is initiated by irradiation with light of the composition further mixed with the chain transfer agent and the photoinitiator, and the time is increased from 5 ° C to 50 ° C from the temperature of the composition at the time when the bulk polymerization is started; Stopping the bulk polymerization; (d) performing the step (b) and the step (c) once or repeatedly, and the (meth) acrylic system comprising a (meth) acrylic polymer having a polydispersity index (PDI) of 3 to 10; Forming a syrup; And (e) forming a pressure-sensitive adhesive layer formed by curing the (meth) acrylic syrup on both sides of the base material layer, thereby preparing a double-sided adhesive tape.

The double-sided pressure-sensitive adhesive tape and its manufacturing method can be realized at the same time excellent adhesion, excellent deformation resistance and excellent impact resistance.

1 is a schematic cross-sectional view of a double-sided adhesive tape according to an embodiment of the present invention.
2 is a schematic process flowchart of a double-sided adhesive tape according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. In the drawings, the thicknesses of layers and regions are exaggerated for clarity.

In the following, any configuration is formed on the top (or bottom) of the substrate or on the top (or bottom) of the substrate, not only means that the arbitrary configuration is formed in contact with the top (or bottom) of the substrate, but also the substrate It is not limited to not including other configurations between and any configuration formed on (or under) the substrate.

In one embodiment of the invention, the substrate layer; And a pressure-sensitive adhesive layer laminated on both sides of the base layer, wherein the pressure-sensitive adhesive layer has a polydispersity index (PDI) of greater than 5 and less than or equal to 10 or less. It provides a double-sided adhesive tape comprising a. The said (meth) acrylic-type syrup can also be called a (meth) acrylic-type composition or a (meth) acrylic-type syrup composition.

In general, bulk polymerization can be used to achieve eco-friendliness, high yield and economical efficiency, such as bulk thermal polymerization initiated by heat or bulk photopolymerization initiated by light.

In the case of bulk thermal polymerization, since the reaction rate is relatively small, the productivity is smaller, and even after the temperature is lowered, the polymerization may continue to some extent at room temperature, thereby changing physical properties.

On the other hand, in the case of using the bulk photopolymerization, the reaction rate is fast, and the productivity is high, but when the light is blocked, the polymerization is no longer performed at room temperature, so the storage stability against temperature is excellent, but the reaction may occur explosively and control the reaction. There is a problem that it is difficult to uniformly prepare acrylic syrup having a desired level of conversion.

In addition, in the case of using such a bulk photopolymerization, it is difficult to control the reaction, and thus an acrylic syrup is usually manufactured in a one-step reaction, whereby the range of the polydispersity index is narrow.

In addition, when the acrylic syrup having a wide polydispersity index is used, including polymers having different weight average molecular weights as necessary, acrylic syrups containing polymers having a large weight average molecular weight and polymers having a small weight average molecular weight may be used. Each of the acryl-based syrups must be separately prepared, and then a mixing process of mixing them is additionally applied. At this time, polymers having a low weight average molecular weight are not easily mixed between polymers having a high weight average molecular weight, and thus have low compatibility. Characteristics can be difficult to implement. The polydispersity index (PDI) may be defined as a value obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn) (Mw / Mn).

Thus, in one embodiment of the present invention, the double-sided adhesive tape is a pressure-sensitive adhesive layer containing a cured product formed of a (meth) acrylic syrup having a polydispersity index of, for example, more than 5, specifically, more than 5 and less than 10. By using the excellent adhesion, excellent deformation resistance and excellent impact resistance can be realized at the same time.

Specifically, the (meth) acrylic syrup is a bulk polymerization that is initiated by irradiation of light by appropriately controlling the amount of temperature change from the time of starting the bulk polymerization through a manufacturing method according to another embodiment to be described later so that the reaction does not explode. It can be easily formed using, the double-sided adhesive tape including a cured product thereof can implement excellent productivity and excellent storage stability.

In addition, the (meth) acrylic syrup is formed by performing the bulk polymerization in a multistage rather than a one-step reaction to have a low conversion rate and a high polydispersity index, thereby controlling the physical properties of the cured product in a wider range. Physical properties of the double-sided adhesive tape including a cargo can be appropriately adjusted according to the purpose and use of the invention can be applied to more various applications.

In addition, since the (meth) acrylic syrup is formed in one process as a whole, it is possible to omit an additional mixing process of separately preparing polymers having different chain lengths or molecular weights and then mixing them, and at the same time, Since different (meth) acrylic polymers can be more uniformly mixed and compatibility can be effectively improved, their complementary properties such as adhesion; and deformation resistance and impact resistance; There is an advantage that can be implemented at a level.

In one embodiment, the substrate layer may include a film or a foam of a thermoplastic resin material.

The thermoplastic resin film is, for example, urethane resin, acrylic resin, polyamide resin, polyester resin, polyether resin, polypropylene-polyethylene resin, polypropylene resin, polyethylene terephthalate resin, polybutylene terephthalate resin , Polystyrene resins, acrylonitrile-styrene resins, acrylonitrile-butadiene-styrene resins, polyphenylene sulfide resins, nylon resins, polyether imide resins, and combinations thereof. However, the present invention is not limited thereto.

In addition, the thickness of the thermoplastic resin film may be, for example, about 15㎛ to about 180㎛. By having a thickness within the above range can be achieved sufficient mechanical properties and adhesiveness without excessively increasing the total thickness of the double-sided adhesive tape.

The foam may include, for example, at least one selected from the group consisting of olefin foam, polyurethane foam, polyisocyanurate foam, acrylic foam, rubber foam, and combinations thereof. Specifically, it may include an acrylic foam.

The foam may be formed by foaming and curing the foaming composition including at least one selected from the group consisting of an olefin polymer, a polyurethane polymer, a polyisocyanurate polymer, an acrylic polymer, and a combination thereof.

For example, the foam is formed by performing any one of UV irradiation and heat treatment, or sequentially UV irradiation and heat treatment for the foam composition when the foaming composition further comprises a filler for forming pores. When the foaming composition does not further include a pore-forming filler, the foaming composition may be formed by performing UV irradiation while injecting gas into the foaming composition.

The pore-forming filler may include, for example, at least one selected from the group consisting of a polymer micro-hollow sphere, a glass bubble, a glass macro balloon, and a combination thereof.

In addition, the pore-forming filler may include pre-expanded foam particles, non-foamed foam particles, or both.

The UV irradiation may be performed, for example, for about 3 minutes to about 8 minutes at a UV irradiation amount of about 3 W / cm ² to about 10 W / cm ² , but is not limited thereto. In addition, the heat treatment may be performed at, for example, about 80 ° C. to about 200 ° C. for about 3 minutes to about 10 minutes, but is not limited thereto.

For example, the foam may have an average diameter of about 10 μm to about 100 μm. In addition, the foam may have a density of about 0.1 kg / m ³ to about 1.0 kg / m ³ , for example.

The foam may have a thickness of, for example, about 80 μm to about 2,500 μm. By having a thickness within the above range can be achieved sufficient mechanical properties and adhesiveness without excessively increasing the total thickness of the double-sided adhesive tape.

The adhesive layer may include a cured product of a (meth) acrylic syrup including a (meth) acrylic polymer having a polydispersity index (PDI) of greater than about 5 and about 10 or less. As such, the (meth) acrylic syrup having a high polydispersity index has a wider degree of distribution of the chain length or molecular weight of the (meth) acrylic polymer included therein, so that the cured product formed by curing it has a different chain length or molecular weight. Complementary properties of the (meth) acrylic polymer can be suitably harmonized, whereby the adhesive layer realizes excellent adhesiveness, excellent deformation resistance and excellent impact resistance at the same time, so that the double-sided adhesive tape can be applied to more various applications.

The (meth) acrylic syrup may include, for example, about 10% to about 30% by weight of the (meth) acrylic polymer having a polydispersity index of greater than about 5 and about 10 or less.

The (meth) acrylic polymer may be formed by carrying out a bulk polymerization reaction by irradiation of light to a composition containing a (meth) acrylic monomer and a photoinitiator, and the (meth) acrylic polymer may have a polymerization conversion. For example, it may be formed from about 6% to about 50%, specifically about 6% to about 30% by weight. That is, the (meth) acrylic monomer may have a polymerization conversion rate of, for example, about 6% to about 50%, specifically, about 6% to about 30% by weight of the (meth) acrylic polymer.

As described above, the (meth) acrylic polymer in the (meth) acrylic syrup is formed to have a high polydispersity index and has a low polymerization conversion, so that photocuring proceeds in the process of applying the (meth) acrylic syrup to a predetermined product. It can be controlled in a wider range, and accordingly, the conditions of the photocuring process for applying the (meth) acrylic syrup to the product can be controlled within a wide range according to the purpose and use of the invention to more various physical properties It can be given.

The (meth) acrylic syrup may have a viscosity of about 1,000 cps to about 100,000 cps at about 20 ° C. By having a viscosity in the above range can be more uniformly mixed with other other additives and the like in a subsequent process for applying it to a product, for example, it can be more easily processed into a film, coating, foam or the like.

In addition, the (meth) acrylic syrup does not contain an organic solvent, it can implement excellent environmental friendliness.

The adhesive layer may have an adhesive force of about 1,000 gf / in to about 4,000 gf / in, for example, about 2,500 gf / in to about 3,500 gf / in. The adhesive force may mean adhesive force measured on the plastic substrate. By having an adhesive force within the above range it is possible to effectively prevent the sliding or falling phenomenon by implementing excellent adhesiveness when removing from a predetermined substrate, it is possible to prevent more damage to the substrate, such as, for example, window panel of a television It is possible to more stably fix heavy parts and the like.

The adhesive layer may have a thickness of, for example, about 10 μm to about 100 μm, and specifically about 50 μm to about 75 μm. By having a thickness within the above range, the impact resistance, deformation resistance, strength and tack can be sufficiently achieved without increasing the total thickness of the double-sided adhesive tape excessively.

In one embodiment, the impact strength of the double-sided adhesive tape may be about 720mJ to about 1500mJ. By having an impact strength within the above range it can effectively absorb the external shock to implement excellent impact resistance, for example, is used for fixing the window panel of a mobile device such as a mobile phone, such as broken or dropped mobile It can effectively prevent damage or deterioration of equipment.

The double-sided adhesive tape may be applied to, for example, a double-sided adhesive tape for fixing the window panel of the display device, and the display device may be, for example, a TV or a mobile device. As described above, the double-sided adhesive tape can be realized at an excellent level by appropriately combining adhesiveness, deformation resistance, and impact resistance, so that it is light, but external impact such as touch is less applied, as well as mobile devices to which external shock such as touch is applied. However, each window panel of a heavy TV can be fixed more securely.

In addition, the double-sided adhesive tape may be applied for fixing automobile parts, fixing cells inside a battery, fixing lights or signs, but the use thereof is not limited thereto.

In another embodiment of the present invention, (a) a bulk polymerization is initiated by irradiation of light to a composition comprising a (meth) acrylic monomer and a photoinitiator, and from 5 ° C. to the temperature of the composition at the time when the bulk polymerization is initiated. Stopping the bulk polymerization at a time point of 50 ° C. increase; (b) further mixing the chain transfer agent and the photoinitiator with the composition after stopping the bulk polymerization; (c) the bulk polymerization is initiated by irradiation with light of the composition further mixed with the chain transfer agent and the photoinitiator, and the time is increased from 5 ° C to 50 ° C from the temperature of the composition at the time when the bulk polymerization is started; Stopping the bulk polymerization; (d) performing the step (b) and the step (c) once or repeatedly, and the (meth) acrylic system comprising a (meth) acrylic polymer having a polydispersity index (PDI) of 3 to 10; Forming a syrup; And (e) forming a pressure-sensitive adhesive layer formed by curing the (meth) acrylic syrup on both sides of the base material layer, thereby preparing a double-sided adhesive tape. By the above production method, the double-sided adhesive tape described above may be manufactured in one embodiment.

The production method is suitable for controlling the temperature change amount, specifically, the temperature increase amount from the start of the bulk polymerization so that the reaction does not occur explosively and can easily use the bulk polymerization initiated by the irradiation of light, so that excellent productivity and excellent storage Stability can be achieved.

By forming the bulk polymerization in a multistage rather than a one-step reaction, it has a low conversion rate and a high polydispersity index so that the physical properties of the cured product can be controlled in a wider range. Physical properties can be appropriately adjusted according to the purpose and use of the invention can be applied to more various applications.

In addition, since the (meth) acrylic syrup is formed in one process as a whole, it is possible to omit an additional mixing process of separately preparing polymers having different chain lengths or molecular weights and then mixing them, and at the same time, Since different (meth) acrylic polymers can be more uniformly mixed and compatibility can be effectively improved, their complementary properties such as adhesion; and deformation resistance and impact resistance; There is an advantage that can be implemented at a level.

In the above production method, (a) a bulk polymerization is initiated by irradiation of light to a composition containing a (meth) acrylic monomer and a photoinitiator, and 5 ° C to 50 ° C is set from the temperature of the composition at the time when the bulk polymerization is started. Terminating the bulk polymerization at an increased time point. That is, in the step (a), the bulk polymerization may be stopped at a time when the temperature of the composition is increased by, for example, 5 ° C. to 50 ° C. from the temperature at which the bulk polymerization starts. Can be stopped at the time point increased by 5-20 ° C.

In this way, the bulk photopolymerization is used to emit volatile organic solvents and the like, which is environmentally friendly and the reaction rate is faster than the bulk thermal polymerization, and thus the manufacturing efficiency is high, thereby improving productivity. In addition, since the polymerization reaction no longer proceeds from the point at which the bulk polymerization is stopped by the irradiation of ultraviolet rays, the physical properties of the prepared (meth) acrylic syrup can be maintained at a more uniform level, thereby effectively improving the storage stability with respect to temperature. Can be.

In addition, as described above, the above-mentioned (meth) acrylic monomer may be controlled by appropriately controlling the temperature change amount from 5 ° C. to 50 ° C. as described above, from the time point at which the bulk polymerization is started, as described above. The conversion rate of can be adjusted to an appropriately low level.

In addition, according to the step (a), the composition may not include a chain transfer agent, and nevertheless, a (meth) acrylic polymer having an appropriate weight average molecular weight may be formed by controlling the temperature change amount of the composition.

The method may further include preparing the composition including the same by mixing about 0.001 part by weight to about 1 part by weight of the photoinitiator based on about 100 parts by weight of the (meth) acrylic monomer.

By including a photoinitiator in an amount within the above range, it is possible to appropriately generate radicals necessary for bulk photopolymerization to easily control the conversion rate of the acryl crab monomer.

The (meth) acrylic monomers include, for example, (meth) acrylic acid ester monomers including alkyl groups having about 1 to about 20 carbon atoms; (Meth) acrylic acid ester monomers including a hydroxy group, a carboxyl group, or an amine group; And at least one selected from the group comprising a combination thereof.

Specifically, the (meth) acrylic monomer is methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-octyl (meth ) Acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydrate Hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) Acrylate or 2-hydroxypropylene glycol ( L) acrylate, can include methacrylic acid, at least one selected from the group including acrylic acid, and combinations thereof, but is not limited to this.

In addition, the composition may be prepared by further mixing the vinyl monomer. The vinyl monomers are, for example, vinyl acetate, ethyl acetate, methyl methacrylate, styrene, (meth) acrylic acid, hydroxyl ethyl acrylate, (meth) acrylamide, N-methyl acrylamide, N-ethyl acrylamide , N-hydroxyethyl acrylamide, diacetone acrylamide, N, N-dimethyl acrylamide, N, N-diethyl acrylamide, N-ethyl-N-aminoethyl acrylamide, N-ethyl-N-hydroxy Oxyethyl acrylamide, N, N-dihydroxyethyl acrylamide, t-butyl acrylamide, N, N-dimethylaminoethyl acrylamide and N-octyl acrylamide, itaconic acid, crotonic acid, maleic acid, fumaric acid, 2,2- (diethoxy) ethyl acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, methyl (meth) acrylate, isobornyl acrylate, 2- (Phenoxy) Methyl (meth) acrylate, biphenylyl acrylate, t-butylphenyl acrylate, cyclohexyl acrylate, dimethyladamantyl acrylate, 2-naphthyl acrylate, phenyl acrylate, N-vinyl formamide, It may include, but is not limited to, at least one selected from the group consisting of N-vinyl acetamide, N-vinyl pyrrolidone, and combinations thereof.

The photoinitiator may absorb light in a wavelength of about 100 nm to about 400 nm. By absorbing light having a wavelength in the above range, the radicals can be easily formed by irradiation of ultraviolet rays so that polymerization can proceed effectively.

Such photoinitiators are, for example, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, diphenyl- (2,4,6-trimethylbenzoyl) -force Pin oxide, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1-hydroxy-cyclohexylphenyl-ketone, benzophenone, 4-benzoyl-4'-methyldiphenyl Sulfide, methyl-2-benzoyl benzoate, isopropyl thioxanthone, ethyl-4- (dimethylamino) benzoate, 2-ethylhexyl-4-dimethylaminobenzoate, hydroxy dimethyl acetophenone, 2,4-diethyl It may include, but is not limited to, at least one selected from the group consisting of thioxanthone, 4-phenylbenzophenone, and combinations thereof.

In the step (a), the weight average molecular weight of the (meth) acrylic polymer formed to the point of stopping the bulk polymerization is about 1,000,000g / mol to about 10,000,000g / mol, polydispersity index is about 2 to about 2.7 days Can be.

As described above, the step (a) may not include a chain transfer agent, thereby forming (meth) acrylic polymers having a range of high levels of weight average molecular weight, thereby forming a range of small levels of weight average molecular weight. Almost no (meth) acrylic polymers are formed, so the polydispersity index may be at a low level within this range.

 In the above production method, nitrogen purging may be performed on the composition before the bulk polymerization is initiated by irradiation with light. Accordingly, since the oxygen present in the composition is replaced by nitrogen, radicals generated from the photoinitiator by irradiation of light cannot react with oxygen and are not consumed, so that the polymerization reaction can proceed efficiently.

In addition, for example, stirring may be performed on the composition while performing the nitrogen purge. As such, by carrying out the stirring together, the oxygen in the composition can be replaced with nitrogen more easily, so that the polymerization reaction can proceed more efficiently.

Nitrogen purging and stirring of the composition can be carried out continuously until the final (meth) acrylic syrup is prepared, that is, until the final end of the reaction, and may be carried out thereafter as necessary.

In the step (a), the temperature of the composition at the time when the bulk polymerization is initiated by the irradiation of light may be formed to about 15 ℃ to about 60 ℃.

As the temperature of the composition is lowered, the weight average molecular weight of the acrylic polymer formed by the bulk photopolymerization can be formed at a relatively higher level. The weight of the acrylic polymer formed by the bulk photopolymerization by forming at a temperature within the above range is achieved. The average molecular weight can be appropriately adjusted to the desired level.

In one embodiment, (b) further mixing a chain transfer agent and a photoinitiator with the composition after stopping the bulk polymerization; And (c) initiating bulk polymerization by irradiation of light to the composition further mixed with the chain transfer agent and the photoinitiator, and at a time when 5 ° C to 50 ° C is increased from the temperature of the composition at the time when the bulk polymerization is started. The bulk polymerization may be stopped. Specifically, the bulk polymerization may be stopped at a time when 5 ° C to 20 ° C is increased.

At this time, the (meth) acrylic polymer formed in step (a) no longer contains an unsaturated bond capable of initiating bulk polymerization by light, so even if the step (b) and the step (c) are applied, the weight average The range of molecular weights can be maintained as is.

(Meth) acrylic syrup comprising a (meth) acrylic polymer having a polydispersity index (PDI) of about 3 to about 10 by performing step (b) and step (c) once or repeatedly. Can be prepared.

As such, by further mixing the chain transfer agent to advance the bulk photopolymerization, the range of the weight average molecular weight of the (meth) acrylic polymer formed in the step (c) may be lower than that of the (meth) acrylic polymer formed in the step (a), Accordingly, the degree of distribution of the molecular weight of the (meth) acrylic polymer finally present in the (meth) acrylic syrup can be further widened, thereby realizing a polydispersity index at a high level of about 3 or more.

That is, the manufacturing method is different from the conventional method of producing an acrylic syrup by separately forming (meth) acrylic polymers having different ranges of weight average molecular weight from each other and then mixing them by an additional mixing process. By repeating the steps (b) and (c) according to the range of the weight-average molecular weight of the (meth) acrylic polymer formed every time to the (meth) acrylic polymer of the (meth) acrylic polymer contained in the (meth) acrylic syrup Not only can the distribution degree of the molecular weight be increased, but also they can be mixed more uniformly.

As a result, the polydispersity index of the (meth) acrylic polymer included in one (meth) acrylic syrup to be finally manufactured can be controlled to a high level, so that the complementary properties can be effectively harmonized and applied to more diverse applications. have.

When repeating steps (b) and (c), from about 0.0001 parts by weight to 100 parts by weight of the total of the (meth) acrylic monomers using the chain transfer agent in step (b) in step (b) And about 1.0 part by weight.

In this case, about 30% to about 40% by weight of the chain transfer agent is used for the bulk photopolymerization based on the total content of the mixed chain transfer agent during the step (c). The weight percent may remain as unreacted compound.

Therefore, when the steps (b) and (c) are repeated one more time, even if the same amount of chain transfer agent is mixed in step (b), the total content of the chain transfer agent present in the composition is not reacted. Since the content of the chain transfer agent remaining as a compound is also included, the total content of the chain transfer agent present in the composition may be different each time when the steps (b) and (c) are repeated.

In the above production method, for example, as the content of the chain transfer agent present in the composition increases before starting the bulk polymerization in the step (c), it is formed until the point at which the bulk polymerization is stopped in the step (c). The (meth) acrylic polymer may have a reduced range of its weight average molecular weight as a whole.

Specifically, the step (b) and the step (c) can be performed once to three times, thereby implementing the polydispersity index of the (meth) acrylic polymer at a high level as described above and bulk The polymerization can be carried out in multiple stages to achieve good compatibility.

For example, when the step (b) and the step (c) is performed once, the entire (meth) acrylic type formed in the composition until the point at which the bulk polymerization is stopped in the first step (c). The weight average molecular weight of the polymer may be from about 100,000 g / mol to about 3,000,000 g / mol and the polydispersity index may be greater than about 2.7 to about 3.5. At this time, in the present specification, the entire (meth) acrylic polymer formed in the composition is not only the (meth) acrylic polymer formed by the step (b) and the step (c), but also the (meth) formed in the step (a) It may be meant to include all acrylic polymers.

In addition, for example, when the step (b) and the step (c) is performed a second time, the total (meta) formed in the composition until the point at which the bulk polymerization is stopped in the second step (c) The acrylic polymer may have a weight average molecular weight of about 10,000 g / mol to about 1,000,000 g / mol and a polydispersity index of greater than about 3.5 to about 5.0.

Further, for example, when the step (b) and the step (c) is performed for the third time, the (meth) acrylic polymer of the (meth) acrylic polymer formed until the point at which the bulk polymerization is stopped in the third step (c) The weight average molecular weight may be about 5,000 g / mol to about 20,000 g / mol and the polydispersity index may be greater than about 5.0 to about 10.0.

The chain transfer agent may include, for example, at least one selected from the group consisting of alkyl mercaptan having 2 to 18 carbon atoms, benzyl mercaptan, mercapto acid, alpha methyl styrene dimer, and combinations thereof. However, the present invention is not limited thereto.

In addition, the (meth) acrylic syrup that is finally formed may be formed to include, for example, about 10% by weight to about 30% by weight of the (meth) acrylic polymer.

In addition, the (meth) acryl-based polymer in the (meth) acrylic-based syrup that is finally formed may have a polymerization conversion of, for example, about 6% to about 50%, specifically about 6 Weight percent to about 30 weight percent. That is, the (meth) acrylic monomer may have a polymerization conversion rate of, for example, about 6% to about 50% to the (meth) acrylic polymer, and specifically, about 6% to about 30% by weight. Can be formed.

As described above, the (meth) acrylic polymer in the (meth) acrylic syrup is formed to have a high polydispersity index and has a low polymerization conversion, so that photocuring proceeds in the process of applying the (meth) acrylic syrup to a predetermined product. It can be controlled in a wider range, and accordingly, the conditions of the photocuring process for applying the (meth) acrylic syrup to the product can be controlled within a wide range according to the purpose and use of the invention to more various physical properties It can be given.

In addition, the (meth) acrylic syrup may have a viscosity of about 1000 cps to 100,000 cps at about 20 ° C. By having a viscosity in the above range can be more uniformly mixed with other other additives and the like in a subsequent process for applying it to a product, for example, it can be more easily processed into a film, coating, foam or the like.

In one embodiment, after the (meth) acrylic-based syrup is finally formed, performing the purging with an oxygen-containing inert gas for the composition; may further include.

Accordingly, oxygen may be dissolved in and included in the (meth) acrylic syrup formed by the manufacturing method. Accordingly, after the production is completed, a small amount of oxygen remaining in the (meth) acrylic syrup is exposed to light such as ultraviolet rays. Even if radicals are generated from the photoinitiator, the radicals can be consumed by reacting with dissolved oxygen.

Accordingly, the (meth) acrylic syrup can sufficiently consume radicals generated by dissolved oxygen even when exposed to light, so that a bulk polymerization reaction is not initiated, thereby achieving excellent storage stability for light, and at the same time, As described above, since the bulk polymerization reaction is not started even by heat treatment or the like, excellent storage stability with respect to temperature can be realized.

As such, the (meth) acrylic syrup has excellent storage stability not only for temperature but also for light, so that even after distribution, the (meth) acrylic syrup can maintain uniform physical properties before being applied to an actual product regardless of temperature change and exposure to light. have.

The oxygen containing inert gas may contain about 10% by volume to about 30% by volume of oxygen. By including the content within the above range can shorten the time to perform the purging to reduce the time and cost, while preventing the explosiveness can be realized at the same time excellent economy and excellent stability.

In addition, the oxygen-containing inert gas may include at least one selected from the group consisting of nitrogen, argon, helium, neon, and combinations thereof.

While purging with the oxygen-containing inert gas, stirring may be performed on the composition together. Therefore, when oxygen is fully dissolved in the (meth) acrylic syrup and exposed to light, the progress of the polymerization reaction can be effectively suppressed.

Purging may be carried out with an oxygen-containing inert gas to the composition until the temperature of the composition reaches at least about 20 ° C. to about 50 ° C., after which it may be purged with an oxygen-containing inert gas.

The bulk photopolymerization, which is an exothermic reaction, is stopped from the time point at which the irradiation of the light is stopped, so that the temperature is lowered in the process of purging the composition. It can be sufficiently dissolved in the composition without leaving it.

In another embodiment, (e) by forming a pressure-sensitive adhesive layer formed by curing the (meth) acrylic syrup on both sides of the base layer, it is possible to manufacture a double-sided adhesive tape. The substrate layer and the adhesive layer are as described above in one embodiment.

The adhesive layer may be formed by performing thermal curing, photocuring, or both of the (meth) acrylic syrup, and the thermal curing may be, for example, a temperature of about 85 ° C to about 120 ° C and about 3 minutes to It may be carried out under a time condition of about 5 minutes, the photocuring is carried out under the conditions of UV irradiation amount of about 4.0W / cm ² to about 5.5W / cm ² and time of about 4 minutes to about 6 minutes, for example. It may be, but is not limited to these, and may be appropriately changed according to methods known in the art.

The adhesive layer may be formed such that the adhesive force is, for example, about 1,000 gf / in to about 4,000 gf / in, and specifically, may be formed to about 2,500 gf / in to about 3,500 gf / in. By forming to have an adhesive force within the above range it is possible to effectively prevent the sliding or falling phenomenon by implementing excellent adhesiveness when removing from a predetermined substrate, it is possible to further prevent the damage of the substrate, etc., for example, the window of the television Heavy parts, such as a panel, can be fixed more stably.

In addition, the adhesive layer may have a thickness of, for example, about 10 μm to about 100 μm, and specifically, about 50 μm to about 75 μm. By having a thickness within the above range, the impact resistance, deformation resistance, strength and tack can be sufficiently achieved without sacrificing the total thickness of the double-sided adhesive tape.

In the manufacturing method, a step of preparing the base layer, including a film or a foam of a thermoplastic resin material may be further included.

The substrate layer may be prepared by extruding a thermoplastic resin to form a film or by foaming and curing the foaming composition.

Extrusion of the thermoplastic resin may be performed according to a method known in the art, for example, a calendering process and the like may be used, but is not limited thereto.

The foaming composition is the same as described above in one embodiment, the foaming and curing thereof can be carried out according to methods known in the art, for example, to be carried out using heat treatment, UV irradiation or both Can be. Specifically, when the foaming composition further comprises a filler for forming a pore, the foaming composition may be formed by performing any one of UV irradiation and heat treatment, or sequentially performing both UV irradiation and heat treatment. When the foaming composition does not further include a pore-forming filler, the foaming composition may be formed by performing UV irradiation while injecting gas into the foaming composition. The UV irradiation and the heat treatment are as described above in one embodiment.

For example, the foam may be formed so that the average diameter of the foam cells thereof is about 10 μm to about 100 μm. In addition, the foam may be formed to have a density of about 0.1 kg / m ³ to about 1.0 kg / m ³ , for example.

The thickness of the thermoplastic resin film may be, for example, about 15 μm to about 180 μm. By forming a thickness within the above range can be achieved sufficient mechanical properties and adhesiveness without excessively increasing the total thickness of the double-sided adhesive tape.

In addition, the foam may have a thickness of, for example, about 80 μm to about 2,500 μm. By forming a thickness within the above range can be achieved sufficient mechanical properties and adhesiveness without excessively increasing the total thickness of the double-sided adhesive tape.

In another embodiment, the impact strength of the double-sided adhesive tape may be formed to be about 720mJ to about 1,500mJ. By forming to have an impact strength within the above range can effectively absorb the external shock to implement excellent impact resistance, for example, is used for fixing the window panel of a mobile device such as a mobile phone damage or performance The fall can be prevented effectively.

The following presents specific embodiments of the present invention. However, the embodiments described below are merely for illustrating or explaining the present invention in detail, and the present invention is not limited thereto.

Example

Example  One

<step (a)>

The composition was prepared by mixing 100 parts by weight of an acrylic monomer including EHA (ethylhexylacrylate), MA (metacrylic acid) and AA (acrylic acid), and 0.05 parts by weight of the photoinitiator IRG 184.

Nitrogen purging was carried out for 30 minutes with nitrogen while stirring the composition, and then the composition was irradiated with UV light at 40 mW / cm ² using a metal halide lamp while continuing stirring and nitrogen purging. Bulk polymerization was initiated and the temperature of the composition at the time of starting the bulk polymerization was 30 ° C.

The bulk polymerization was interrupted by stopping the irradiation of the ultraviolet rays when the temperature of the composition was increased 15 ° C. from the temperature at which the bulk polymerization was initiated while the temperature of the composition was continuously measured.

<step (b)>

Then, 0.03 parts by weight of a chain transfer agent (n-dodecyl mercaptan, n-DDM) based on a total of 100 parts by weight of the (meth) acrylic monomers included in the step of preparing the composition in the composition while stirring and nitrogen purging are continued. 0.05 parts by weight of photoinitiator (IRG 184) was further mixed.

<step (c)> and <step (d)>

Subsequently, bulk polymerization is initiated by irradiation of light to the composition further mixed with the chain transfer agent and the photoinitiator while stirring and nitrogen purging are continued, and the temperature of the composition is 15 from the time point at which the bulk polymerization is started. The bulk polymerization was stopped at the time point increased to 占 폚. At this time, the composition was irradiated with ultraviolet rays at 40 mW / cm ² using a metal halide lamp to initiate bulk polymerization, and the temperature of the composition at the time of starting the bulk polymerization was 35 ° C.

Further, the nitrogen purging was then stopped while the stirring of the composition was continued, and purging with an oxygen-containing inert gas (oxygen: 15% by volume, 85% by volume of nitrogen) was performed at the point where the temperature of the composition reached 30 ° C. (Meta) acrylic syrup was formed by stopping after

<(e) step>

The base material layer was prepared by the 150-micrometer-thick acryl-type foam.

Subsequently, the double-sided adhesive tape was prepared by applying the (meth) acrylic syrup on both sides of the substrate layer and irradiating a total of 5.5 W / cm ² UV for 5 minutes to form an adhesive layer having a thickness of 50 μm.

Example  2

Steps (a), (b), (c), (b) and (c) were sequentially performed under the same conditions and methods as in Example 1.

Further, the nitrogen purging was then stopped while the stirring of the composition was continued, and purging with an oxygen-containing inert gas (oxygen: 15% by volume, 85% by volume of nitrogen) was performed at the point where the temperature of the composition reached 30 ° C. (Meta) acrylic syrup was formed by stopping after

<(e) step>

The base material layer was prepared by the 150-micrometer-thick acryl-type foam.

Subsequently, the double-sided adhesive tape was prepared by applying the (meth) acrylic syrup on both sides of the base layer and performing heat treatment at 85 ° C. to 115 ° C. for 3 minutes to form a 50 μm adhesive layer, respectively.

Comparative Example 1 (When Bulk Thermal Polymerization was Used)

Prepare a composition by mixing 100 parts by weight of the acrylic monomer containing EHA (ethylhexylacrylate), MA (metacrylic acid), AA (acrylic acid) and 0.005 parts by weight of AIBN of the thermal initiator, and heat treatment at 70 ℃ for 1 hour to bulk heat A double-sided pressure-sensitive adhesive tape was manufactured under the same conditions and methods as in Example 1 except that the (meth) acrylic syrup was prepared by polymerization.

Comparative Example 2 (When the heat treatment time is longer than Comparative Example 1)

Prepare the composition by mixing 100 parts by weight of the acrylic monomer containing EHA (ethylhexylacrylate), MA (metacrylic acid), AA (acrylic acid) and 0.005 parts by weight of AIBN of the thermal initiator, and heat treatment at 70 ℃ for 2 hours A double-sided pressure-sensitive adhesive tape was manufactured under the same conditions and methods as in Example 1 except that the (meth) acrylic syrup was prepared by polymerization.

Comparative Example 3 (When bulk photopolymerization was used but the temperature change was less than)

<step (a)>

The composition was prepared by mixing 100 parts by weight of an acrylic monomer including EHA (ethylhexylacrylate), MA (metacrylic acid) and AA (acrylic acid), and 0.05 parts by weight of the photoinitiator IRG 184.

Nitrogen purging was carried out for 30 minutes with nitrogen while stirring the composition, and then the composition was irradiated with UV light at 40 mW / cm ² using a metal halide lamp while continuing stirring and nitrogen purging. Bulk polymerization was initiated and the temperature of the composition at the time of starting the bulk polymerization was 30 ° C.

The bulk polymerization was interrupted by stopping the irradiation of the ultraviolet rays when the temperature of the composition was increased 4 ° C. from the temperature at which the bulk polymerization was initiated while the temperature of the composition was continuously measured.

<step (b)>

Then, 0.03 parts by weight of a chain transfer agent (n-dodecyl mercaptan, n-DDM) based on a total of 100 parts by weight of the (meth) acrylic monomers included in the step of preparing the composition in the composition while stirring and nitrogen purging are continued. 0.05 parts by weight of photoinitiator (IRG 184) was further mixed.

<(c) step>

Subsequently, bulk polymerization is initiated by irradiation of light to the composition further mixed with the chain transfer agent and the photoinitiator while stirring and nitrogen purging are continued, and the temperature of the composition is 15 from the time point at which the bulk polymerization is started. The bulk polymerization was stopped at the time point increased to 占 폚. At this time, the composition was irradiated with ultraviolet rays at 40 mW / cm ² using a metal halide lamp to initiate bulk polymerization, and the temperature of the composition at the time of starting the bulk polymerization was 35 ° C.

In addition, Example 1, except that (meth) acrylic syrup was prepared by continuing the agitation of the composition while stopping the nitrogen purging until the temperature of the composition reached 30 ℃ and then stopped. The double-sided adhesive tape was prepared under the same conditions and methods.

Comparative Example 4 (When bulk photopolymerization was used, but the temperature change amount was exceeded)

In the step (a), the same conditions and methods as in Comparative Example 3 were performed except that the irradiation of the ultraviolet rays was stopped when the temperature of the composition was increased by 55 ° C from the temperature at which the bulk polymerization was started. A double-sided adhesive tape was prepared.

evaluation

The weight average molecular weight and the polydispersity index of the (meth) acrylic polymers contained in each of the (meth) acrylic syrups used in Examples 1 and 2 and Comparative Examples 1-4 were measured and described in Table 1 below. Various physical properties of each (meth) acrylic syrup were evaluated and described together in Table 1 below.

In addition, the physical properties of the double-sided pressure-sensitive adhesive tape according to Examples 1, 2 and Comparative Examples 1-4 and each of the pressure-sensitive adhesive layers contained therein were evaluated and described in Table 2 below.

Experimental Example

Experimental Example  1: weight average molecular weight and Polydispersion  Indices

Measuring method: The solids of each of the (meth) acrylic syrups according to Examples 1 and 2 and Comparative Examples 1-4 were dissolved in Chloroform at a concentration of 0.25% by weight, and gel permeation chromatography (manufacturer: Agilent 1200, Column ): Mixed-A * 2ea, PLgel 10㎛ Guard * 1ea, Detector: RID) was used to determine the weight average molecular weight and number average molecular weight. Next, the polydispersity index (Mw / Mn) was calculated by dividing the measured weight average molecular weight (Mw) by the measured number average molecular weight (Mn).

Flow rate: 1.0 mL / min, solvent: THF, standard: polystyrene.

Experimental Example  2: conversion rate

Measuring method: 10.000 g of the (meth) acrylic syrup according to Examples 1 and 2 and Comparative Examples 1-4 was added dropwise to methanol, and the acrylic polymer precipitated in the methanol was filtered and then heated to 60 ° C. and 24 in a vacuum oven. It dried on the conditions of time, and then the mass of the solid content formed by drying was measured. The conversion rate was calculated according to the following equation 1 using the mass of the solid content.

[Equation 1]

% Conversion = M ₂ / M ₁ Ⅹ 100

In the above formula _1, M 1 is the mass of the acrylate syrup was added dropwise to methanol, M2 is the mass of the dried solid formed.

Experimental Example  3: viscosity

Measurement method: Under the conditions of 20 ℃, it was measured using a viscometer (Brookfield, DV-II + Pro).

Experimental Example  4: Storage stability over temperature

Measuring method: (meth) acrylic syrup according to Examples 1 and 2 and Comparative Examples 1-4 were maintained at 60 ° C. for 24 hours in a high-temperature chamber (Zeotech, ON-22), respectively, and whether the conversion rate was changed In the case of no change in conversion rate, the storage stability with respect to temperature was evaluated as "○", and when the conversion rate was increased, the storage stability with respect to temperature was evaluated as "Ⅹ".

Experimental Example  5: Storage stability against light

Measuring method: After measuring the (meth) acrylic syrup according to Examples 1, 2 and Comparative Examples 1-4 to sunlight (10mw / cm ² or more based on UVA) for 10 minutes, the change of the conversion rate was measured. In the case of no change in the conversion rate, the storage stability for light was evaluated as "○", and when the conversion rate was increased, the storage stability for light was evaluated as inferior.

Experimental Example  6: high temperature shear direction retention

Measuring method: Two SUS 304 1 / 2H blocks of 30 mm × 50 mm were prepared, which were washed once with IPA and three times with heptane, and also double-sided adhesive according to Examples 1, 2 and Comparative Examples 1-4. Each specimen was prepared by cutting a 25 mm × 25 mm tape.

Subsequently, one of the blocks is attached to one surface of each of the specimens, and the other of the blocks is attached to the other surface of each of the specimens, and the blocks are attached to protrude slightly in the opposite directions to each other, followed by a 7 kg roller. Press and reciprocate twice at 25 mm / sec rate using, and then left for 1 hour under conditions of RT 23 ℃ and RH 50% to prepare each sample.

Subsequently, one of each of the blocks protruding from both ends of the sample is fixed to a predetermined upper surface (upper surface), and the other is suspended at a weight of 500 grams so that a force is applied in the direction of gravity and the temperature of RH is 85 ° C. The time until dropping was also measured while measuring the pushed distance (mm) of the weight which was placed in a high temperature and high humidity chamber at 85% humidity condition and left for 3 hours.

Experimental Example  7: adhesion

Measuring method: Peel strength was measured using a universal testing machine (UTM) (Texture Analyzer XT Plus, Stable micro systems), and the adhesion was evaluated through this.

Specifically, a polycarbonate base material was prepared in a size of 30 mm × 300 mm and washed once with IPA and three times with heptane, and the double-sided adhesive tapes according to Examples 1 and 2 and Comparative Examples 1-4 were prepared. The specimens were prepared by cutting into 25 mm × 200 mm sizes.

Subsequently, each specimen was attached to the substrate, and then pressed back and forth twice at a speed of 25 mm / sec using a 2 kg roller, and a 50 μm-thick PET film was attached to the opposite side of the double-sided adhesive tape as a backing film. After pressing and reciprocating twice at a rate of 25mm / sec using a 2kg roller, and then left for 24 hours under conditions of RT 23 ℃ and RH 50% to prepare each sample.

Subsequently, a PET film (30 × 150 mm × 0.1 mm) was attached to one end of the backing film of each sample so as to protrude slightly, and thus the peeling force was peeled off by flipping the protruding portion to 180 ° and peeling off the substrate of the polycarbonate material. Specifically, the peel force was measured at a peel rate of 300 mm / min and a peel angle of 180 ° at room temperature, and the maximum value of the forces measured from the time point at which peeling was started to the time point at which the peeling was completed was performed as the peel force. Evaluated.

Experimental Example  8: Deformation resistance

Measuring method: 155mmX30mmX0.5mm sized aluminum? The substrate and a polycarbonate substrate having a size of 170 mm × 35 mm × 2 mm were prepared and washed once with IPA and three times with heptane, and the double-sided adhesive tapes according to Examples 1 and 2 and Comparative Examples 1-4 were cut into 150 mm × 25 mm sizes, respectively. Prepared specimens.

Subsequently, the specimen is attached to the aluminum substrate such that one edge portion of the aluminum substrate and one edge portion of the specimen coincide with each other, and pressed back and forth twice with a 7 kg roller, and then the opposite side to the surface on which the aluminum substrate of the specimen is attached. Attach the polycarbonate substrate to the edge of the polycarbonate substrate, while one edge portion of the aluminum substrate is aligned so that the aluminum substrate is attached to the center of the polycarbonate substrate and press the reciprocating twice with a 7kg roller Then, each sample was prepared by standing for 24 hours under conditions of RT 23 ° C. and RH 50%.

In addition, each sample was fitted to both ends of the test jig (Al material, 210mmX165mmX5mm) of the universal testing machine, and then placed in a high temperature and high humidity chamber at a temperature of 85 ° C. and a humidity of RH 85%. The peeling time of the specimen attached between the carbonate substrates was observed to determine the time at which the peeling started.

Experimental Example  9: impact resistance

Measuring method: The double-sided adhesive tapes according to Examples 1 and 2 and Comparative Examples 1-4 were measured using a Dupont type impact tester.

Specifically, each of the two-sided adhesive according to the Examples 1, 2 and Comparative Examples 1-4 on a polycarbonate (PC) substrate having a size of 50 mm x 50 mm x 2 mm with a hole having a diameter of 10 mm in the center Attach the glass of 20mmx20mmx3mm through the tape, attach it with the hole in the center, and then press for 1 minute with 3kg force, and leave it for 24 hours under RT 23 ℃ and 50% RH. Ready.

The dropping impact test was performed by observing whether the glass and the double-sided adhesive tape were dropped while dropping the weight of 100 g with respect to the glass surface of the laminate specimen in a position of 50 mm in height from 50 mm to 500 mm in sequence.

In this case, when the glass and the double-sided adhesive tape did not fall off, the dropping impact test was performed while increasing the weight of the weight to 150g, 200g, 300g and 400g until they were dropped, and the weight of the weight was 150g 350 In the case of ~ 500mm, 200g, in the case of 400 ~ 500mm, 300g and 400g, the drop was dropped from the raised position by 50mm sequentially within the height of 350 ~ 500mm.

Accordingly, the weight and height of the weight when the glass and the double-sided adhesive tape were dropped for each of the double-sided adhesive tapes for display according to Examples 1 and 2 and Comparative Examples 1 and 2 were measured, and these techniques were measured. Impact strength was calculated according to physical laws known in the art.

Weight average molecular weight
(g / mol) Polydispersity Conversion rate
(%) Viscosity
(cps) Storage stability against temperature Storage stability for light Example 1 1,850,000 5.82 8.94 4,200 ○ ○ Example 2 1,210,000 7.88 11.42 5,000 ○ ○ Comparative Example 1 420,000 3.15 20.40 2,500 Ⅹ Ⅹ Comparative Example 2 390,000 3.52 24.42 4,000 Ⅹ Ⅹ Comparative Example 3 3,510,000 2.05 4.74 600 ○ Ⅹ Comparative Example 4 3,210,000 3.28 31.15 Not measurable ○ Ⅹ

High temperature shear direction holding force
(Dropout time / back distance) Adhesive force (gf / in) Deformation resistance (min) Impact resistance (mJ) Example 1 More than 10,000 minutes
2 mm 2,800 720 minutes 1,240 mJ Example 2 More than 10,000 minutes
2 mm 3,000 1,500 minutes 1,480 mJ Comparative Example 1 360 minutes left 3,200 720 minutes 980 mJ Comparative Example 2 240 minutes left 3,200 600 minutes 860 mJ Comparative Example 3 More than 10,000 minutes
2 mm 1,800 30 minutes 520 mJ Comparative Example 4 More than 10,000 minutes
2 mm 2,000 102 minutes 640 mJ

As shown in Table 1, the (meth) acrylic syrups used in the adhesive layer formation of the double-sided adhesive tapes according to Examples 1 and 2 all have a polydispersity index of 5.00 or more, and at the same time a wider degree of molecular weight distribution, It was clearly confirmed that the lower than 20%, it can be clearly expected that the excellent workability due to the appropriate viscosity. In addition, all of them have excellent storage stability not only for temperature but also for light, so it can be clearly predicted that even during distribution, uniform physical properties can be maintained until they are applied to the actual product regardless of temperature change and exposure to light. On the other hand, the (meth) acrylic syrups used to form the adhesive layer of the double-sided adhesive tapes according to Comparative Examples 1 and 2, although not shown in Table 1 by using a bulk thermal polymerization reaction, the productivity was too low, especially the storage stability against temperature Inferior and storage stability against light is clearly inferred that there is a problem that physical properties can be easily changed by temperature change or exposure to light until it is applied to the actual product.

In addition, the (meth) acrylic syrup used to form the pressure-sensitive adhesive layer of the double-sided adhesive tape according to Comparative Example 3 has a remarkably low polydispersity index of less than 3.00, so that the molecular weight distribution is very narrow, and the viscosity is too low, so that the workability is inferior. In addition, the storage stability against light was inferior.

In addition, the (meth) acrylic syrup according to Comparative Example 4 was so high that the viscosity could not be measured, the workability was remarkably low, and the storage stability to light was also inferior.

In addition, as shown in Table 2, the double-sided adhesive tapes according to Examples 1 and 2 can be confirmed that both the excellent high-temperature shear direction holding force and adhesion, but also excellent deformation resistance and impact resistance.

On the other hand, the double-sided adhesive tapes according to Comparative Examples 1 and 2 can be clearly expected that they cannot be used for fixing a panel such as a television that must withstand high load due to inferior high temperature shear direction holding force, and Comparative Examples 3 and 4 Double-sided adhesive tape according to it can be seen that the deformation resistance and impact resistance is very inferior.

100: double sided adhesive tape
110: substrate layer
120: adhesive layer

Claims (6)

Base layer; And a pressure-sensitive adhesive layer laminated on both sides of the substrate layer.
A double-sided adhesive tape comprising a cured product of a (meth) acrylic syrup containing a (meth) acrylic polymer having an adhesive layer polydispersity index (PDI) of more than 5 and less than 10.
The method of claim 1,
Impact strength of the double-sided adhesive tape is 720mJ to 1500mJ
Double sided adhesive tape.
The method of claim 1,
Adhesive force of the adhesive layer is 1,000 gf / in to 4,000 gf / in
Double sided adhesive tape.
The method of claim 1,
The base layer includes a thermoplastic resin film or foam
Double sided adhesive tape.
The method of claim 1,
The (meth) acrylic polymer has a polymerization conversion of 6% to 50%.
Double sided adhesive tape.
The method of claim 1,
The (meth) acrylic syrup has a viscosity of 1,000 cps to 100,000 cps at 20 ° C.
Double sided adhesive tape.

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