KR20200064738A - Acrylic emulsion pressure snsitive adhesive composition - Google Patents

Abstract

The present invention relates to an acrylic emulsion adhesive composition, comprising an emulsion polymer and, more specifically, to an acrylic emulsion adhesive composition which implements excellent adhesive properties, has no separate color, and is advantageous for bonding transparent materials and the like by not causing yellowing.

Description

Acrylic emulsion adhesive composition {ACRYLIC EMULSION PRESSURE SNSITIVE ADHESIVE COMPOSITION}

The present invention relates to an acrylic emulsion pressure-sensitive adhesive composition.

Pressure-Sensitive Adhesive (PSA) is a material that has the property of adhering to an adhesive under a small pressure. It is a viscoelastic material different from the adhesive, and has the basic properties of initial adhesion, adhesion, and cohesion, and is used in various industries such as printing, chemicals, pharmaceuticals, home appliances, automobiles, and stationery.

The pressure-sensitive adhesive can be classified into acrylic, rubber, silicone, EVA, etc. according to the monomer used in production, and can be classified into solvent type, emulsion type, and hot melt type depending on the type.

In the past, most rubber-based adhesives or solvent-based adhesives have been used for adhesive tapes and adhesive labels, but as demand for eco-friendly adhesives has increased, interest in solvent-free adhesives has increased, and technology development has progressed. Currently, the use and production of solvent-free adhesives has increased significantly and is expected to continue to increase in the future.

Solvent-free pressure-sensitive adhesives are typically produced by water-based emulsion polymerization, and in terms of improving economic efficiency and processability, there are few aggregates and characteristics that can stably implement excellent adhesive properties are required.

In order for the adhesive properties to be stably implemented, there must be no significant change in the viscosity of the pressure-sensitive adhesive, but the viscosity is changed under the influence of the environment to which the pressure-sensitive adhesive is exposed, such as temperature, humidity, and acidity.

In particular, in recent years, such solvent-free pressure-sensitive adhesives have been widely used for bonding transparent films, etc. Under the influence of the environment, the physical properties of the pressure-sensitive adhesive may change, which may impair the optical properties of the film.

Therefore, even if exposed to various environments, the change in physical properties is not large, and there is a continuing need for an adhesive capable of stably realizing adhesive properties.

The present specification is intended to provide an acrylic emulsion pressure-sensitive adhesive composition capable of stably realizing the adhesion properties, even if exposed to various environments, the property properties are not large.

According to one aspect of the invention,

For the entire repeating unit derived from the monomer constituting the emulsifying polymer,

A) 90 to 98 mol% of repeating units derived from the (meth)acrylic ester-based first monomer containing a chain alkyl group having 1 to 10 carbon atoms; And

B) b1) an acrylic emulsion pressure sensitive adhesive composition comprising an emulsifying polymer composed of 2 to 10 mol% of repeating units derived from at least one monomer selected from the group consisting of unsaturated carboxylic acid-based second monomers and b2) aromatic vinyl-based third monomers Is provided.

The first monomer is methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl ( 1 selected from the group consisting of meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, and lauryl (meth)acrylate It may be more than a species.

In addition, the second monomer may be at least one selected from the group consisting of maleic anhydride, fumaric acid, crotanic acid, itaconic acid, and (meth)acrylic acid.

And, the third monomer is selected from the group consisting of styrene, methyl styrene, methyl styrene, butyl styrene, chloro styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloro methyl styrene, hydroxy methyl styrene and divinyl benzene 1 It may be more than a species.

According to one embodiment of the invention, the acrylic emulsion pressure-sensitive adhesive composition, with respect to the entire repeating unit derived from the monomer constituting the emulsion polymer;

A) a repeating unit derived from the (meth)acrylic ester-based first monomer containing a chain alkyl group having 1 to 10 carbon atoms is about 94 to about 97 mol%;

It is more preferable to include an emulsifying polymer composed of about 3 to about 6 mol% of repeating units derived from one or more monomers selected from the group consisting of B) b1) a second monomer of unsaturated carboxylic acid and b2) a third monomer of aromatic vinyl. can do.

Meanwhile, according to another aspect of the invention,

With respect to the whole monomer component, A) 90 to 98 mol% of (meth)acrylic ester-based first monomers containing a chain alkyl group having 1 to 10 carbon atoms; B) a monomer mixture of 2 to 10 mol% of one or more monomers selected from the group consisting of b1) a second monomer of an unsaturated carboxylic acid and b2) a third monomer of an aromatic vinyl; Polymerization initiators; And it provides a method for producing an acrylic emulsion pressure-sensitive adhesive composition comprising the step of emulsion polymerization of a polymerization composition comprising an emulsifier.

The emulsifier may include one or more selected from the group consisting of anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers.

At this time, the anionic emulsifier, sodium alkyl diphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene aryl ether sulfate, sodium alkyl sulfate, sodium alkyl benzene sulfonate, and dialkyl sodium sulfostone It may include one or more selected from the group consisting of sinate.

In addition, the nonionic emulsifier may include at least one selected from the group consisting of polyethylene oxide alkyl aryl ether, polyethylene oxide alkyl amine, and polyethylene oxide alkyl ester.

The emulsifier may be preferably used in an amount of about 0.01 to about 10 parts by weight, or about 0.1 to about 5 parts by weight based on 100 parts by weight of the monomer component.

And, the composition for polymerization may further include an aqueous solvent.

On the other hand, according to another aspect of the invention, the transparent substrate; An adhesive member is provided on at least one surface of the transparent substrate, which includes an adhesive layer formed by the above-described adhesive composition.

In the adhesive member, the adhesive layer formed by the acrylic emulsion adhesive composition has a b value measured according to CIE 1976 L*a*b* standards of about 0.1 or less, or about 0 to about 0.1, preferably about 0.03 to about 0.1, or about 0.03 to about 0.09.

And, in the adhesive member, the adhesive layer formed by the acrylic emulsion pressure-sensitive adhesive composition, after being exposed for about 3 hours at about 70 ℃, b value measured according to the CIE 1976 L*a*b* standard is about 0.25 or less , Or, about 0 to 0.25, preferably about 0.04 to 0.25, or about 0.04 to about 0.23.

And, the adhesive member, FINAT TEST METHOD NO. 2 The 90 degree peel strength measured according to the standard may be about 5 N/in or more, preferably about 7.5 to about 10 N/in.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another component.

In addition, the terms used herein are only used to describe exemplary embodiments, and are not intended to limit the present invention.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In addition, in this specification, when each layer or element is referred to as being formed “on” or “above” each layer or element, it means that each layer or element is directly formed on each layer or element, or It means that another layer or element can be additionally formed between each layer, on the object or the substrate.

The present invention can be applied to various changes and may have various forms, and specific embodiments will be illustrated and described in detail below. However, it should be understood that the present invention is not limited to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in detail.

According to one aspect of the invention,

For the entire repeating unit derived from the monomer constituting the emulsifying polymer,

A) 90 to 98 mol% of repeating units derived from the (meth)acrylic ester-based first monomer containing a chain alkyl group having 1 to 10 carbon atoms;

B) b1) an acrylic emulsion pressure sensitive adhesive composition comprising an emulsifying polymer composed of 2 to 10 mol% of repeating units derived from at least one monomer selected from the group consisting of unsaturated carboxylic acid-based second monomers and b2) aromatic vinyl-based third monomers Is provided.

In the present specification, that the emulsifying polymer is composed of the repeating units derived from the monomer means that all repeating units derived from the monomer contained in the emulsifying polymer are repeating units derived from the first, second, and third monomers. It is configured, and means that the repeating units derived from other monomers are not included at all. In particular, if any one or more of the repeating units derived from the first monomer and the second and third monomers is added, a total of 100 It means that it is made in mol%.

The inventors of the present invention, in the case of the acrylic emulsion pressure-sensitive adhesive composition containing an emulsion of latex particles prepared by emulsion polymerization of an acrylate-based monomer, etc., in the case of producing latex particles only with a combination of specific monomers, has excellent adhesion, Particularly, even when exposed to an external environment, there was no change in adhesion retention power or color, and the fact that the physical properties can be realized very stably was completed.

First, the acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention includes emulsifying polymer particles of a specific monomer, that is, latex particles, and each monomer is present in the form of repeating units derived from monomers in the latex particles. Can be.

Monomer

First, in the emulsion polymerization for preparing the latex particles, a (meth)acrylic ester-based monomer containing a chain alkyl group having 1 to 10 carbon atoms may be used, which may be referred to as a first monomer. Accordingly, the latex particles may include a repeating unit derived from a (meth)acrylic ester-based monomer containing a chain alkyl group having 1 to 10 carbon atoms, which may be referred to as a first repeating unit.

The first monomer is methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl ( 1 selected from the group consisting of meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, and lauryl (meth)acrylate It may be a species or more, or may be used alone or in combination of two or more.

And, in the emulsion polymerization for producing the latex particles, an unsaturated carboxylic acid-based monomer may be further used, which may be referred to as a second monomer. Accordingly, the latex particles may include a repeating unit derived from an unsaturated carboxylic acid-based monomer, which may be referred to as a second repeating unit.

The second monomer may be at least one selected from the group consisting of maleic anhydride, fumaric acid, crotanic acid, itaconic acid, and (meth)acrylic acid, and may be used alone or in combination of two or more.

And, in the emulsion polymerization for producing the latex particles, an aromatic vinyl-based monomer may be further used, which may be referred to as a third monomer. Accordingly, the latex particles may include a repeating unit derived from an aromatic vinyl monomer, which may be referred to as a third repeating unit.

In addition, the aromatic vinyl-based monomer is selected from the group consisting of styrene, methylstyrene, methylstyrene, butylstyrene, chlorostyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, hydroxymethylstyrene and divinylbenzene. 1 or more types are mentioned.

As described above, the latex particles used in the acrylic emulsion pressure-sensitive adhesive composition according to an aspect of the present invention include: A) a first alkyl (meth)acrylic monomer comprising a chain alkyl group having 1 to 10 carbon atoms and B) b1) Including only the repeating units derived from one or more monomers selected from the group consisting of unsaturated carboxylic acid-based second monomers and b2) aromatic vinyl-based third monomers, it is possible to exhibit excellent adhesion, even when exposed to an external environment, adhesion properties and Optical properties such as color do not change.

In the case of emulsion adhesives using previously used vinyl acetate or other functional group-containing monomers, under the conditions of exposure to the external environment after drying or adhesion, the adhesive properties are deteriorated or the color changes due to yellowing. Can occur.

However, the acrylic emulsion pressure-sensitive adhesive composition according to an aspect of the present invention uses only the above-described first monomer, and second and/or third monomer, and in particular, contains only these monomers in a specific content to realize excellent initial adhesion. In addition, even if exposed to the external environment, there is an advantage that hardly yellowing occurs.

In this respect, the acrylic emulsion pressure-sensitive adhesive composition, A) a repeating unit derived from a (meth)acrylic ester-based first monomer comprising a chain alkyl group having 1 to 10 carbon atoms, about 94 to about 97 mol%; And B) b1) an unsaturated carboxylic acid-based second monomer and b2) an aromatic vinyl-based third monomer. It may be desirable.

If the content exceeds the above range, or other monomers are used, the point of the acrylic emulsion pressure-sensitive adhesive composition to be produced may cause a problem that the adhesive strength is lowered or the adhesive strength is lowered. In particular, the acrylic emulsion pressure-sensitive adhesive composition After the adhesive layer formed by exposure to the external environment, a problem that yellowing may occur may occur.

Acrylic emulsion pressure-sensitive adhesive composition according to an embodiment of the present invention, due to the above-described composition characteristics, the b value measured according to CIE 1976 L*a*b* standards is about 0.1 or less, or about 0 to about 0.1, preferably Is from about 0.03 to about 0.1, or from about 0.03 to about 0.09, and may have little color.

And, the acrylic emulsion pressure-sensitive adhesive composition is exposed for about 3 hours at about 70 ℃, even after drying is complete, the b value measured according to CIE 1976 L*a*b* standards is about 0.25 or less, or from about 0 to 0.25, preferably from about 0.04 to 0.25, or from about 0.04 to about 0.23, the effect of yellowing may be very small.

Emulsion polymerization

Emulsifying polymer particles, that is, latex particles included in the composition according to an embodiment of the present invention;

For the entire monomer component,

A) 90 to 98 mol% of a (meth)acrylic ester-based first monomer comprising a chain alkyl group having 1 to 10 carbon atoms;

B) a monomer mixture of 2 to 10 mol% of one or more monomers selected from the group consisting of b1) a second monomer of an unsaturated carboxylic acid and b2) a third monomer of an aromatic vinyl;

Polymerization initiators; And

Comprising the step of emulsion polymerization of a polymerization composition comprising an emulsifier,

It can be prepared by an emulsion polymerization method.

At this time, the polymerization temperature and polymerization time can be appropriately determined in some cases. For example, the polymerization temperature may be from about 50 °C to about 200 °C, and the polymerization time may be from about 0.5 hour to about 20 hours.

As the polymerization initiator usable in the emulsion polymerization, an inorganic or organic peroxide may be used, for example, a water-soluble polymerization initiator including potassium persulfate, sodium persulfate, ammonium persulfate, and cumene hydroperoxide, Oil-soluble polymerization initiators including benzoyl peroxide and the like can be used.

In addition, an activator may be further included to promote the reaction initiation of the peroxide together with the polymerization initiator, and such activators include sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, and dextrose One or more selected from the group consisting of can be used.

The polymerization initiator may be included in an amount of about 0.1 to about 10 parts by weight based on 100 parts by weight of the monomer mixture on a dry weight basis, preferably about 0.1 to about 5 parts by weight.

According to an embodiment of the present invention, the acrylic emulsion pressure-sensitive adhesive composition may include other additives without particular limitations within a range that does not lower the desired effect of the invention in addition to the above-described components.

Specifically, in order to adjust the pH in the polymerization reaction and to impart polymerization stability, an electrolyte may be further included, for example, sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium phosphate, sodium sulfate, sodium chloride, etc. However, it is not limited to this. Further, these may be used alone or in combination of two or more.

Emulsion polymerization may be specifically carried out through the following steps.

Dispersing the emulsifier in a solvent to prepare an emulsion, the first step;

A second step of mixing a monomer mixture containing each monomer component, an emulsifier, and the like to prepare a free emulsion;

In the presence of a polymerization initiator, the third step of mixing the emulsion of the first step and the pre-emulsion of the second step and proceeding with emulsion polymerization.

In a specific embodiment of the present invention, the above-described acrylic emulsion pressure-sensitive adhesive composition, specifically, may be prepared by the following method, but is not limited thereto.

First, in the first step, an emulsion containing an emulsifier is prepared. This is separate from the following pre-emulsion manufacturing process. Emulsifiers, anionic emulsifiers can be used alone, or anionic emulsifiers, cationic emulsifiers and the nonionic emulsifiers described above can be used together, and these emulsifier components and solvents such as water can be mixed to prepare emulsions. .

In the process of preparing the emulsion, initial micelles of several nanometers in size may be stably formed.

Then, as a second step, a process for preparing a pre-emulsion containing the above-described monomer mixture, a pre-emulsion is prepared by mixing each of the above-described monomers, emulsifiers, etc. with water.

At this time, also as an emulsifier, anionic emulsifiers may be used alone, or anionic emulsifiers and the above-described nonionic emulsifiers may be used together. In this process, nano-sized latex particles may be formed in the pre-emulsion.

That is, the above-described emulsifier can be used in any one or more of the emulsion production step, and pre-emulsion production step.

Then, as a third step, after the polymerization initiator is added to the emulsion prepared above, the pre-emulsion and the polymerization initiator are continuously added for a predetermined time in an equal ratio.

In a non-limiting example of the present invention, the content of the polymerization initiator to be added to the emulsion may be about 0 to about 1 part by weight relative to 100 parts by weight of the monomer mixture, and the content of the polymerization initiator to be added together with the pre-emulsion is The monomer mixture may be about 0.1 to about 2 parts by weight relative to 100 parts by weight of the monomer mixture, and the continuous injection time may be about 3 hours to about 7 hours.

Through this process, suspended monomers or polymers in the free emulsion can be introduced into the initial particles produced in the emulsion.

The results of this reaction may then be subjected to a warm polymerization process in the presence of an additional polymerization initiator, through which polymerization of the remaining monomers is achieved.

At this time, the polymerization initiator may be added from about 0.1 to about 10 parts by weight based on 100 parts by weight of the monomer mixture, and the warm polymerization may be performed at a temperature of about 75 to about 85° C., about 40 minutes to about 80 minutes. .

The method for preparing the acrylic emulsion pressure-sensitive adhesive composition is dualized into an emulsion preparation process and a pre-emulsion manufacturing process, and then can be performed by a simple method of mixing the free emulsion in the emulsion, so that a conventional high solid content, low viscosity acrylic emulsion adhesive Process stability and productivity can be improved compared to methods of preparing the composition.

On the other hand, in the above-described pre-emulsion manufacturing process, a chain transfer agent may be used. The chain transfer agent serves to introduce homopolymers, which are polymers composed of only one type of monomer, into micelles, and may include sodium carbonate, sodium methylallyl sulfonate, n-dodecyl mercaptan, and the like. It is not necessarily limited to this.

And, in one embodiment of the present invention, after the polymerization step, it is possible to further perform the step of adjusting the pH.

The method of adjusting the pH of the acrylic emulsion resin can be used without any particular limitation on the method commonly used in the art, for example, an inorganic substance such as hydroxide, chloride, carbonate of an alkali metal monovalent metal or divalent metal, ammonia Or an organic amine or the like can be used.

Emulsifier

In addition, the emulsifier used in the emulsion polymerization may include one or more selected from the group consisting of anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers.

The emulsifier is a material having a hydrophilic group and a hydrophobic group at the same time. During the emulsion polymerization process, a micelle structure is formed, and polymerization of each monomer can occur within the micelle structure.

Emulsifiers generally used in emulsion polymerization may be divided into anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers, and two or more of them may be mixed with each other in terms of polymerization stability in emulsion polymerization.

Specifically, the nonionic emulsifier may include one or more selected from the group consisting of polyethylene oxide alkyl aryl ether, polyethylene oxide alkyl amine, and polyethylene oxide alkyl ester.

And, the anionic emulsifier, sodium alkyl diphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene aryl ether sulfate, sodium alkyl sulfate, sodium alkyl benzene sulfonate, and dialkyl sodium sulfosuccinate It may include one or more selected from the group consisting of nate.

These may be used alone or in combination of two or more, and may be more effective in the case of mixing and using anionic emulsifiers and nonionic emulsifiers, but the present invention is not necessarily limited to these types of emulsifiers.

In addition, the emulsifier may be used in an amount of about 0.1 to about 10 parts by weight, or about 1 to about 5 parts by weight, for example, with respect to 100 parts by weight of the monomer component used in the preparation of the latex particles.

When the amount of the emulsifier used is too large, the particle diameter of the latex particles becomes small, which may cause a problem that the point and the adhesive strength are lowered. When too little emulsifier is used, the stability of polymerization in the emulsion polymerization reaction decreases, Stability of the resulting latex particles may also be deteriorated.

menstruum

According to one embodiment of the invention, the composition for polymerization may further include an aqueous solvent such as water, in addition to the above-described emulsifier or monomer component.

At this time, the aqueous solvent, in terms of stability and viscosity control of latex particles, with respect to 100 parts by weight of the latex particles, may be used in about 10 to about 1,000 parts by weight, for example, based on the total amount of the composition, the total The solid content (total solid content, TSC) can be used to be adjusted to about 10 to about 60% by weight.

When too little solvent is used, viscosity may increase in the acrylic emulsion pressure-sensitive adhesive composition, and during emulsion polymerization, stability problems of the latex particles may be lowered. When too much solvent is used, the viscosity decreases, resulting in coating properties. This deterioration may occur.

Adhesive member

The acrylic emulsion pressure-sensitive adhesive composition of the present invention prepared according to the above-described method may be applied to an adhesive member such as a pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet may be a film or sheet for the construction interior and exterior materials, interior materials, advertising films, or labels. , The present invention is not necessarily limited to these.

Such a sheet includes a transparent substrate; And an adhesive layer formed on one side or both sides of the transparent substrate, and the adhesive layer may be formed by the above-described acrylic emulsion adhesive composition.

According to one embodiment of the invention, the adhesive member, FINAT TEST METHOD NO. The 90 degree peel strength measured according to the criteria of 2 may be about 5 N/in or more, preferably about 7.5 N/in or more, and the upper limit has no great meaning, but is about 15 N/in or less, or about 10 N/in or less.

As described above, the acrylic emulsion pressure-sensitive adhesive composition according to one embodiment of the present invention, while being able to implement excellent adhesion, especially when exposed to the external environment, the color change is not large, when used for bonding transparent materials, etc. It does not harm its own optical properties.

Hereinafter, the operation and effects of the invention will be described in more detail through specific examples of the invention. However, these examples are only presented as examples of the invention, and the scope of the invention is not thereby determined.

Preparation of acrylic emulsion adhesive composition

Example 1

In a 3 L glass reactor equipped with a thermometer, agitator, dropping funnel, nitrogen gas introduction tube and reflux cooler, 220 g of water and 10 g of sodium polyoxyethylene aryl ether sulfate at a concentration of 26% by weight were added and stirred. After replacing the inside of the reactor with nitrogen, the temperature was raised to 80° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, 4 L of 2-ethyl hexyl acrylate, 90 g of methyl methacrylate, 12 g of styrene, and 6 g of acrylic acid were added to a 2 L beaker, followed by stirring for 30 minutes to prepare a monomer mixture.

Here, a solution comprising 20 g of sodium polyoxyethylene lauryl ether sulfate at a concentration of 26% by weight, 10 g of sodium alkyldiphenyl oxide disulfonate solution at a concentration of 45% by weight, 2 g of sodium carbonate, and 180 g of water is added. And stirred to prepare a cloudy white emulsion.

To the glass reactor containing the emulsion, 3 g of ammonium persulfate at a concentration of 20% by weight was added and dissolved by stirring for 10 minutes.

To the glass reactor, the pre-emulsion and 25 g of ammonium persulfate at a concentration of 7% by weight were continuously and uniformly added for 5 hours, followed by polymerization at 80°C for 1 hour.

This was cooled to room temperature, and the pH was adjusted to 5-7 by adding an aqueous sodium hydroxide solution having a concentration of 10% by weight to prepare an acrylic emulsion pressure-sensitive adhesive composition.

Examples 2 to 6

Acrylic emulsion adhesive in the same manner as in Example 1, except that the type of the monomer and the content of each component of the monomer are different and the content of ammonium persulfate at a concentration of 7% by weight added with the free emulsion is changed. The composition was prepared.

The contents are summarized in Table 1 below.

unit
(g) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 2-EHA 494 374 314 404 349 0 BA 0 120 180 120 180 577 MMA 90 90 90 60 60 12 SM 12 12 12 12 0 0 AA 6 6 6 6 15 15 7% APS 25 25 25 25 102 25

* 2-EHA: 2-ethyl hexyl acrylate; BA: butyl acrylate; MMA: methyl methacrylate; SM: styrene; AA: acrylic acid; 7% APS: Ammonium persulfate at a concentration of 7% by weight

Comparative Example 1

In a 3 L glass reactor equipped with a thermometer, agitator, dropping funnel, nitrogen gas introduction tube and reflux cooler, 220 g of water and 10 g of sodium polyoxyethylene aryl ether sulfate at a concentration of 26% by weight were added and stirred. After replacing the inside of the reactor with nitrogen, the temperature was raised to 80° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, in a 2 L beaker, 379 g of 2-ethyl hexylacrylate, 90 g of butyl acrylate, 60 g of methyl methacrylate, 61 g of vinyl acetate, 15 g of acrylic acid, and 0.6 g of normal-dodecylmercaptan as a molecular weight modifier After the addition, the mixture was stirred for 30 minutes to prepare a monomer mixture.

Here, a solution comprising 20 g of sodium polyoxyethylene lauryl ether sulfate at a concentration of 26% by weight, 10 g of sodium alkyldiphenyl oxide disulfonate solution at a concentration of 45% by weight, 2 g of sodium carbonate, and 180 g of water is added. And stirred to prepare a cloudy white emulsion.

To the glass reactor containing the emulsion, 3 g of ammonium persulfate at a concentration of 20% by weight was added and dissolved by stirring for 10 minutes.

To the glass reactor, the pre-emulsion and 102 g of ammonium persulfate at a concentration of 7% by weight were uniformly continuously added for 5 hours, followed by polymerization at 80°C for 1 hour.

This was cooled to room temperature, and the pH was adjusted to 5-7 by adding an aqueous sodium hydroxide solution having a concentration of 10% by weight to prepare an acrylic emulsion pressure-sensitive adhesive composition.

Comparative Example 2

An acrylic emulsion pressure-sensitive adhesive composition was prepared in the same manner as in Comparative Example 1, except that the content of ammonium persulfate at a concentration of 7% by weight added with the free emulsion was changed.

The contents are summarized in Table 2 below.

unit
(g) Comparative Example 1 Comparative Example 2 2-EHA 379 379 Vac 61 61 BA 90 90 MMA 60 60 AA 15 15 n-DDM 0.6 0.6 7% APS 102 25

* 2-EHA: 2-ethyl hexyl acrylate; Vac: vinyl acetate; BA: butyl acrylate; MMA: methyl methacrylate; AA: acrylic acid; n-DDM: n-dodecylmercaptan; 7% APS: Ammonium persulfate at a concentration of 7% by weight

Adhesive member manufacturing

The acrylic emulsion pressure-sensitive adhesive composition prepared above was coated on a release paper with a thickness of 20 μm, dried at 120° C. for 1 minute, and laminated to a polypropylene film to prepare an adhesive member.

The physical properties of the adhesive member were measured as follows.

Adhesive property measurement

1) 90 degree peel strength measurement

For the adhesive member prepared above, measured according to FTM 2 of the FINAT test method, prepared a specimen with a size of 1 inch x 20 cm, attached to a stainless steel plate (SUS), and 300 mm/ with a 2 kg roller It was compressed by reciprocating twice at a speed of min. After aging at room temperature for 20 minutes, it was measured while peeling at a rate of 300 mm/min using a TA Texture Analyzer instrument for 5 seconds.

2) How to measure the shear force

For the adhesive member prepared above, measured in accordance with FTM 8 of the FINAT test method, prepare a specimen with a size of 1 inch x 20 cm, and attach it so that the stainless steel surface and the attachment surface are 1 inch x 0.5 inch. , Compressed by reciprocating twice with a 2 kg roller. After 10 minutes, the attached sheet was attached to an inclined wall surface about 2 degrees, and a weight of 1000 g was applied at the bottom, and the time when the sheet fell from the attached surface was measured in a measurement environment of 23° C. and 50% humidity.

Color measurement

For the adhesive member prepared above, the value of b measured according to CIE 1976 L*a*b* standards was measured using Color-Eye 7000A of X-rite, and here, the polypropylene film used as the substrate By subtracting the b value of, the b value of the acrylic emulsion pressure-sensitive adhesive composition itself was obtained. (b1)

After exposing the adhesive member at 70° C. for 3 hours, the b value of the acrylic emulsion pressure-sensitive adhesive composition itself was measured again in the same manner, and the change was examined. (b2)

The adhesive properties and color values measured above are summarized in Table 3 below.

Peel strength
(N/in) retention
(1 in *0.5 in, 1 kg)
(Hr) Color, △b b1 b2 Example 1 8 > 100 0.046 0.051 Example 2 7.6 > 100 0.064 0.094 Example 3 7.3 > 100 0.068 0.1 Example 4 6.7 > 100 0.065 0.093 Example 5 5.7 > 100 0.083 0.13 Example 6 5.1 > 100 0.077 0.217 Comparative Example 1 7.7 > 100 0.587 0.669 Comparative Example 2 6.2 > 100 0.268 0.351

Referring to Table 3, it can be seen that the acrylic emulsion pressure-sensitive adhesive composition according to the embodiment of the present application has excellent peel strength and excellent adhesion retention as well as colorlessness and transparency.

In particular, in the case of the comparative example, it can be seen that the b values according to the CIE 1976 L*a*b* standards are about 0.27, and about 0.59, and the index values are high from the initial stage and greatly increase after exposure to the external environment.

However, in the case of the embodiment, it can be seen that the initial values are all 0.1 or less, and even after being exposed to the external environment, values of 0.1 or less are maintained except for a part.

Claims (15)

For the entire repeating unit derived from the monomer constituting the emulsifying polymer,
A) 90 to 98 mol% of repeating units derived from the (meth)acrylic ester-based first monomer containing a chain alkyl group having 1 to 10 carbon atoms; And
B) b1) 2 to 10 mol% of repeat units derived from one or more monomers selected from the group consisting of unsaturated carboxylic acid-based second monomers and b2) aromatic vinyl-based third monomers;
Acrylic emulsion pressure-sensitive adhesive composition comprising an emulsion polymer.
According to claim 1,
The first monomer is methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl ( 1 selected from the group consisting of meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, and lauryl (meth)acrylate Acrylic emulsion pressure-sensitive adhesive composition of more than one species.
According to claim 1,
The second monomer is at least one selected from the group consisting of maleic anhydride, fumaric acid, crotanic acid, itaconic acid, and (meth)acrylic acid, acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
The third monomer is at least one selected from the group consisting of styrene, methyl styrene, methyl styrene, butyl styrene, chloro styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloro methyl styrene, hydroxy methyl styrene and divinylbenzene , Acrylic emulsion pressure-sensitive adhesive composition.
According to claim 1,
A) 94 to 97 mol% of repeating units derived from a (meth)acrylic ester-based first monomer containing a chain alkyl group having 1 to 10 carbon atoms; And
B) b1) an acrylic emulsion pressure-sensitive adhesive composition comprising an emulsifying polymer composed of 3 to 6 mol% of repeat units derived from one or more monomers selected from the group consisting of unsaturated carboxylic acid-based second monomers and b2) aromatic vinyl-based third monomers .
For the entire monomer component,
A) 90 to 98 mol% of a (meth)acrylic ester-based first monomer comprising a chain alkyl group having 1 to 10 carbon atoms;
B) a monomer mixture of 2 to 10 mol% of one or more monomers selected from the group consisting of b1) a second monomer of an unsaturated carboxylic acid and b2) a third monomer of an aromatic vinyl;
Polymerization initiators; And
Comprising the step of emulsion polymerization of a polymerization composition comprising an emulsifier,
Method for producing acrylic emulsion pressure-sensitive adhesive composition.
The method of claim 6,
The emulsifier, an anionic emulsifier, a cationic emulsifier, and a method for producing an acrylic emulsion pressure sensitive adhesive composition comprising at least one selected from the group consisting of nonionic emulsifiers.
The method of claim 7,
The anionic emulsifiers include sodium alkyl diphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene aryl ether sulfate, sodium alkyl sulfate, sodium alkyl benzene sulfonate, and dialkyl sodium sulfosuccinate. Method for producing an acrylic emulsion pressure-sensitive adhesive composition comprising at least one selected from the group consisting of.
The method of claim 7,
The nonionic emulsifier, polyethylene oxide alkyl aryl ether, polyethylene oxide alkyl amine, and polyethylene oxide containing at least one member selected from the group consisting of alkyl ester, a method for producing an acrylic emulsion pressure-sensitive adhesive composition.
The method of claim 6,
The emulsifier is a method for producing an acrylic emulsion pressure sensitive adhesive composition, which is used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the monomer component.
The method of claim 6,
The polymerization composition further comprises an aqueous solvent, a method for producing an acrylic emulsion pressure-sensitive adhesive composition.
Transparent substrates;
On at least one side on the transparent substrate, comprising an adhesive layer formed by the acrylic emulsion pressure-sensitive adhesive composition according to claim 1,
Adhesive member.
The method of claim 12,
The adhesive layer is an adhesive member having a b value of 0.1 or less measured according to CIE 1976 L*a*b* standards.
The method of claim 12,
The adhesive layer, after being exposed at 70° C. for 3 hours, an adhesive member having a b value of 0.25 or less measured according to CIE 1976 L*a*b* standards.
The method of claim 12,
FINAT TEST METHOD NO. 2 An adhesive member having a 90 degree peel strength, measured according to the standard, of 5 N/in or more.