KR102343797B1 - Pressure sensetive adhesive composition - Google Patents

Abstract

The present invention relates to pressure sensitive adhesive compositions. The pressure-sensitive adhesive composition according to the present invention contains a base resin and a tackifying resin having different weight average molecular weight values at the same time, and while having excellent points, adhesive properties and excellent processability, does not show a special color, so transparency is important It can be used for a variety of purposes in industrial fields that require

Description

Pressure-sensitive adhesive composition {PRESSURE SENSETIVE ADHESIVE COMPOSITION}

The present invention relates to pressure sensitive adhesive compositions.

Pressure-sensitive adhesives generally include polymers prepared from various monomers containing unsaturated double bonds, such as vinyl-based monomers or (meth)acrylate-based monomers.

The pressure-sensitive adhesive may contain various types of monomers to improve adhesive properties, such as cohesive strength of the adhesive composition and shear adhesion during bonding. Adhesive force may fall.

At this time, rosin-based compounds such as rosin esters are used for the purpose of imparting adhesive force to the adhesive. The rosin-based compounds contain various impurities in the form of a mixture using rosin as a raw material, and abietic acid, the main component, is Since it has a double bond in the molecule, it can cause polymerization inhibition in the polymerization reaction of the adhesive, and has a unique color according to the light absorption of the double bond, and then deterioration or yellowing by light can occur.

Accordingly, a method of improving the light resistance of a polymer resin by adding a separate ultraviolet absorber or light stabilizer has been proposed. However, when a sufficient amount of the light stabilizer is used to obtain the light stabilization effect, there is a problem in that the stability of the polymerization reaction is greatly reduced during the polymerization of the monomer, and the adhesion and adhesion properties of the polymer to be prepared are rather adversely affected. do.

Accordingly, it is necessary to study a pressure-sensitive adhesive or a tackifying resin used therein that can implement excellent adhesion and adhesive properties, and also have excellent optical properties, such as color.

The present invention, including a base resin and a tackifying resin having different weight average molecular weight values at the same time, while having excellent points, adhesive properties, and excellent processability, does not show a special color, which can implement excellent transparency, reduced pressure An object is to provide an adhesive composition.

the present invention

A)

a1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and

a2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;

a3) a crosslink formed by a crosslinking agent between the repeating units;

a4) a weight average molecular weight value of 80,000 to 250,000 g/mol,

base resin; and

B)

b1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and

b2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;

b3) a crosslink formed by a crosslinking agent between the repeating units;

b4) a weight average molecular weight value of from 1,000 to 12,000 g/mol;

comprising a tackifying resin;

A pressure sensitive adhesive composition is provided.

In addition, the present invention,

write; and

Formed on at least one surface of the substrate, comprising an adhesive layer formed by the pressure-sensitive adhesive composition described above,

An adhesive member is provided.

The pressure-sensitive adhesive composition of the present invention can maintain low-viscosity properties by simultaneously including a base resin and a tackifying resin having different weight average molecular weight values, and thus, excellent processability, points, and adhesive properties while being able to implement , it has excellent transparency and can be used in various industrial fields.

According to one aspect of the present invention,

A)

a1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and

a2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;

a3) a crosslink formed by a crosslinking agent between the repeating units;

a4) a weight average molecular weight value of 80,000 to 250,000 g/mol,

base resin; and

B)

b1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and

b2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;

b3) a crosslink formed by a crosslinking agent between the repeating units;

b4) a weight average molecular weight value of from 1,000 to 12,000 g/mol;

comprising a tackifying resin;

A pressure sensitive adhesive composition is provided.

In this case, the base resin may have a viscosity value (LV#3, 12rpm) of 500 cPs to 2,000 cPs measured at 25° C. according to the ISO 2555 standard according to the above-described characteristics.

In addition, the tackifying resin may have a viscosity value (LV#3, 12rpm) of 100cPs to 400cPs measured at 25° C. according to the ISO 2555 standard.

In addition, the pressure-sensitive adhesive composition may have a viscosity value (LV#3, 12rpm) of 400cps to 1700cps measured at 25°C according to the ISO 2555 standard.

At this time, the tackifying resin may be included in an amount of about 1 to about 30 parts by weight, preferably about 5 to about 30 parts by weight, and most preferably about 15 to about 25 parts by weight based on 100 parts by weight of the base resin. .

According to an embodiment of the present invention, the molecular weight distribution (PDI) of the base resin may be about 4 to about 6, and the molecular weight distribution (PDI) of the tackifying resin may be about 1 to about 3.

And, according to another embodiment of the invention, in the pressure-sensitive adhesive composition, a1) a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group used in the base resin is b1) C1 used in the tackifying resin -C14 is the same as the (meth)acrylic acid ester-based monomer having an alkyl group,

The a2) unsaturated carboxylic acid monomer having a C1-C14 alkyl group used in the base resin may be the same as b2) the unsaturated carboxylic acid monomer having a C1-C14 alkyl group used in the tackifying resin.

The above-described pressure-sensitive adhesive composition, due to the above characteristic composition, when coated to a thickness of about 20 μm, when exposed to a condition of about 100 ° C. for about 2 hours, the color index change, expressed by the following Equation 1, is about 0.2 to about 1.0, almost no color change, and excellent optical properties can be implemented.

[Equation 1]

|b2-b1|

In Equation 1 above,

b1 is the b* color index value, according to CIELAB 1976 criteria, before exposure to 100 °C conditions,

b2 is the b* color index value according to the CIELAB 1976 standard after exposure to 100° C. conditions for 2 hours.

On the other hand, according to another aspect of the present invention,

write; and

Formed on at least one surface of the substrate, comprising an adhesive layer formed by the pressure-sensitive adhesive composition according to claim 1,

An adhesive member is provided.

At this time,

The thickness of the adhesive layer may be about 10 to about 100 μm.

And, the adhesive member, according to FINAT TEST FTM 11 standard, 180degree-peel strength value of 7N/in or more, preferably about 9N/in or more, or about 9 to about 10N/in, have excellent adhesive properties can

In addition, the terminology used herein is used only to describe exemplary embodiments, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as "comprise", "comprising" or "have" are intended to designate the existence of an embodied feature, number, step, element, or a combination thereof, but one or more other features or It should be understood that the existence or addition of numbers, steps, elements, or combinations thereof, is not precluded in advance.

Also in the present invention, when it is said that each layer or element is formed "on" or "over" each layer or element, it means that each layer or element is formed directly on each layer or element, or other It means that a layer or element may additionally be formed between each layer, on the object, on the substrate.

Since the present invention may have various changes and may have various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

In the present specification, pressure sensitive adhesive (PSA) is a concept as opposed to structural adhesive, and includes all adhesives that generate adhesive force when pressure is applied after the adhesive is applied to the target surface of the adherend. , solvent-type, solvent-free type, hot-melt type, etc. It is used to encompass all adhesives or pressure-sensitive adhesives whose adhesion generation is affected by pressure, regardless of whether or not a solvent or solvent is used or heated in the manufacturing process.

In general, it is very important for a pressure-sensitive adhesive composition to secure adhesion-related physical properties, such as adhesiveness, adhesion retention, and peel strength, depending on its use and properties.

These physical properties can be significantly changed not only by the thermoplastic resin and the base resin component included in the pressure-sensitive adhesive composition, but also by the tackifier, which imparts tackiness to the base resin, thereby increasing the applicability to adherends of various properties.

As the tackifier, rosin-based compounds such as rosin esters, dicyclopentadiene-based (DCPD) polymerized petroleum resins, and the like have conventionally been generally used.

Here, the rosin refers to abietic acid, dehydro-abietic acid in which hydrogen is removed from abietic acid, and dihydro, or tetrahydroabiet in which two or four hydrogens are added. As a mixed composition containing both acids (Dihydro-, Tetrahydro-), abietic acid and dihydroabietic acid to which two hydrogens are added, depending on the position of the double bond, is used as a concept including all of the various isomers.

In the case of dehydroabietic acid, it may be represented by the following formula.

That is, dehydroabietic acid has the most stable form among the rosin compounds by removing two hydrogens from the abietic acid structure including two double bonds and forming an aromatic ring.

And, in the case of abietic acid, which can be seen as a basic form of rosin compounds, it may be represented by the following formula (2).

That is, abietic acid has a stable form by conjugation of two double bonds in a triple-ring compound, and a characteristic color is expressed by this conjugation double bond. In addition, abietic acid, in the above structure, can easily change the position of the double bond, and thus has various forms of isomers. Most of these isomers also have a conjugated double bond, resulting in a characteristic color will have

In the case of dihydroabietic acid, two hydrogens are added to the above isomer of abietic acid, and there is only one double bond in the molecule, and the position of the double bond depends on the isomer structure of abietic acid before hydrogenation. may vary.

In addition, in the case of tetrahydroabietic acid in which 4 hydrogens are added to abietic acid, hydrogen is added to all double bonds to have a saturated aliphatic triple ring form, and thus abietic acid having a double bond Compared to derivatives, it has high stability and no color appearance.

That is, dehydroabietic acid has the most stable form among the rosin compounds by removing two hydrogens from the abietic acid structure including two double bonds and forming an aromatic ring.

And, in the case of abietic acid, which can be seen as a basic form of rosin compounds, it may be represented by the following formula.

That is, abietic acid may have a stable form by conjugating two double bonds in a triple ring compound. The position of such a double bond can be easily changed, and accordingly, it has various forms of isomers. Most of these isomers also have a conjugated double bond.

In the case of dihydroabietic acid, two hydrogens are added to the above isomer of abietic acid, and there is only one double bond in the molecule, and the position of the double bond depends on the isomer structure of abietic acid before hydrogenation. may vary.

In addition, in the case of tetrahydroabietic acid in which 4 hydrogens are added to abietic acid, hydrogen is added to all double bonds to have a saturated aliphatic triple ring form, and thus abietic acid having a double bond Compared to derivatives, it has high stability and no color appearance.

In addition, the rosin ester-based compound mentioned above is esterified by reacting the carboxyl group of abietic acid with the OH group of alcohol or polyol based on the above-described abietic acid or hydrogenated abietic acid structure, Again, this includes both natural rosin or esterified rosin modified. The alcohol or polyol is, for example, an aliphatic alcohol having 1 to 20 carbon atoms, and may be in the form of a monoalcohol, diol, triol, tetraol, or pentaol, and more specifically, for example, methanol, ethanol, glycerol, ethylene glycol, diethylene glycol, or pentaerythritol, and the like. When a polyol is used, abietic acid may undergo an esterification reaction with all or part of the hydroxyl groups of the polyol, so that polyvalent esters, such as monoesters, diesters, ternary esters, or quaternary esters, are can be formed.

However, these rosin-based compounds have a triple ring structure in which three hexagonal rings are connected; And due to the presence of a conjugating double bond, which delocalizes the electron distribution inside the triple ring, it has a characteristic yellow color.

In addition, when such a rosin-based compound is used in a pressure-sensitive adhesive for high adhesion, a relatively large amount is added compared to the base resin. Since the rosin-based compound is a natural material and its unit price is high, can also be a factor.

In addition, the dicyclopentadiene-based polymerized petroleum resin is produced from C5, that is, cyclopentadiene fraction, produced as a by-product in the naphtha cracking process, in which naphtha obtained by refining crude oil is decomposed at a high temperature. It means a petroleum resin containing cyclopentadiene.

Cyclopentadiene generated in the naphtha cracking process, in most cases, is dimerized and exists in a dicyclopentadiene structure. Interconversion is possible by the reaction, in particular cyclopentadiene can be polymerized to dicyclopentadiene by thermal polymerization or catalytic polymerization.

As the tackifier, the above-mentioned dicyclopentadiene-based polymerized petroleum resin, hydrogenated petroleum resin in which hydrogen is added to at least a part of dicyclopentadiene-based compound contained therein, etc. was used

However, this dicyclopentadiene-based polymerized petroleum resin also has a characteristic color and odor, so it is difficult for a pressure-sensitive adhesive containing the same to be used in fields requiring excellent optical properties, especially compatibility with an acrylic-based water-based pressure-sensitive adhesive I had this bad problem.

Accordingly, according to one aspect of the present invention, the pressure-sensitive adhesive composition,

A)

a1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and

a2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;

a3) a crosslink formed by a crosslinking agent between the repeating units;

a4) a weight average molecular weight value of 80,000 to 250,000 g/mol,

base resin; and

B)

b1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and

b2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;

b3) a crosslink formed by a crosslinking agent between the repeating units;

b4) a weight average molecular weight value of from 1,000 to 12,000 g/mol;

A tackifying resin is included.

That is, the pressure-sensitive adhesive composition according to one aspect of the present invention is characterized in that it does not include a rosin-based compound and a dicyclopentadiene-based polymerized petroleum resin, which have been generally used as a tackifier component.

The (meth)acrylic acid ester-based monomer having an alkyl group of C1-C14, that is, the (meth)acrylic acid ester-based monomer having an alkyl group having 1 to 14 carbon atoms, is a material generally used in the technical field to which the present invention belongs. No, specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylic Rate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl ( Meth) acrylate, t-octyl (meth) acrylate, n-ethylhexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, tri Decyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, dodecyl (meth) acrylate, and cyclohexyl ( It may be at least one selected from the group consisting of meth) acrylate, lauryl (meth) acrylate, seryl (meth) acrylate, glycidyl (meth) acrylate, and stearyl (meth) acrylate, and at least two can be used in combination. Specifically, one or two or more selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate may be used.

And, the unsaturated carboxylic acid monomer having the C1-C14 alkyl group is also not particularly limited as long as it is a material generally used in the technical field to which the present invention belongs, and specifically, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, One or two or more selected from the group consisting of glutaric acid, itaconic acid, tetrahydrophthalic acid, corotonic acid, isocrotonic acid and nadic acid may be used.

The base resin may have a weight average molecular weight of 80,000 to 250,000 g/mol, preferably, about 80,000 to about 200,000 g/mol, or about 100,000 to about 200,000.

In addition, the tackifying resin may have a weight average molecular weight of 1,000 to 12,000 g/mol, preferably, about 4,000 to about 11,000 g/mol, or about 4,000 to about 7,000 g/mol.

That is, when the base resin and the tackifying resin used in the pressure-sensitive adhesive composition of the present invention have the weight average molecular weight value as described above, they may have excellent viscosity properties, and accordingly, the pressure-sensitive adhesive composition produced is , it is possible to implement excellent adhesive properties for various adherends.

When the above range is not satisfied, when the base resin and the tackifying resin are mixed, the cohesive force of the adhesive component is lowered, so that the adhesion-related physical properties may be lowered, and further, the processability of the pressure-sensitive adhesive composition may be lowered. .

And, according to an embodiment of the invention, the molecular weight distribution (PDI) of the base resin may be about 4 to about 6, and the molecular weight distribution (PDI) of the tackifying resin is about 1 to about 3, preferably about 1.5 to about 2.5.

That is, as the base resin and the tackifying resin have one molecular weight distribution characteristic, it is possible to implement roles as the base resin and the tackifying resin, respectively, in the adhesive composition using the same.

At this time, and the base resin, according to the above-described characteristics, according to the ISO 2555 standard, at 25 ° C., Brookfield viscometer, according to LV # 3, the viscosity value measured at 12 rpm (LV # 3, 12 rpm) It may be from about 500 to about 2,000 cPs, preferably from about 1,000 to about 1,500 cPs.

As the viscosity of the base resin falls within the above range, the flowability of the pressure-sensitive adhesive composition is improved, and adhesion and cohesive force are improved, so that it can have excellent processability even at a relatively low temperature.

In addition, the tackifying resin has a viscosity value (LV#3, 12rpm) of about 100 to about 400 cPs, preferably about 100 to about 200 cPs, measured according to the same method, to the base resin, excellent adhesion and coatability can be given

Accordingly, the pressure-sensitive adhesive composition may have a viscosity value (LV#3, 12rpm) of about 400 to about 1700 cPs measured according to the same method.

At this time, the tackifying resin may be included in an amount of about 1 to about 30 parts by weight, preferably about 5 to about 30 parts by weight, and most preferably about 15 to about 25 parts by weight based on 100 parts by weight of the base resin. .

In conventional pressure-sensitive adhesive compositions, rosin-based compounds used for tackifying, dicyclopentadiene-based polymerized petroleum resins, etc. have a problem in that the optical properties of the base resin are greatly reduced, and the unit price is increased.

However, in the case of the pressure-sensitive adhesive composition according to an aspect of the present invention, even without using a rosin-based compound or a dicyclopentadiene-based polymerized petroleum resin, equivalent or better adhesive properties can be implemented than before, and when using an adhesive, Since there is no special color, excellent optical properties such as transparency can be realized, and the unit price is lower than that of rosin, which is a natural material, so it can have economic advantages.

And, according to another embodiment of the invention, in the pressure-sensitive adhesive composition, a1) a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group used in the base resin is b1) C1 used in the tackifying resin -C14 is the same as the (meth)acrylic acid ester-based monomer having an alkyl group,

The a2) unsaturated carboxylic acid monomer having a C1-C14 alkyl group used in the base resin may be the same as b2) the unsaturated carboxylic acid monomer having a C1-C14 alkyl group used in the tackifying resin.

That is, as the base resin and the tackifying resin, as a copolymer of the same component is used, there may be no particular problem in compatibility, etc., and optical-related physical properties may be more easily adjusted, and the pressure-sensitive adhesive prepared accordingly It is possible to simultaneously implement excellent adhesion and excellent transparency in the composition.

The pressure-sensitive adhesive composition described above, due to the above characteristic composition, when coated to a thickness of about 20 μm, when exposed to a condition of about 100° C. for about 2 hours, the color index change rate, expressed by the following Equation 1, is about 0.2 to about 1.0, almost no color change, and excellent optical properties can be implemented.

[Equation 1]

|b2-b1|

In Equation 1 above,

b1 is the b* color index value, according to CIELAB 1976 criteria, before exposure to 100 °C conditions,

b2 is the b* color index value according to the CIELAB 1976 standard after exposure to 100° C. conditions for 2 hours.

In addition, the pressure-sensitive adhesive composition according to an embodiment of the present invention, if necessary, may further include known additives such as light stabilizers, fillers, antioxidants, ultraviolet absorbers.

These additives may be included in an amount of about 0.1 to about 10 wt%, preferably about 0.1 to about 1 wt%, based on the total composition, in terms of preventing deterioration of adhesion properties, processability, and mechanical properties after adhesion.

On the other hand, according to another aspect of the present invention,

write; and

Formed on at least one surface of the substrate, comprising an adhesive layer formed by the pressure-sensitive adhesive composition according to claim 1,

An adhesive member is provided.

The adhesive member may be in the form of a film or tape, and the substrate may be a film having a laminated structure of one layer or two or more layers.

The base film may be made of paper, glass, or non-woven fabric, but is preferably made of a plastic material. Although it does not specifically limit as such a plastic material, For example, Polyester, such as a polyethylene terephthalate, a polyethylene naphthalate, a polybutylene terephthalate, and a polybutylene naphthalate; polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyvinyl alcohol; polyvinylidene chloride; polyvinyl chloride; vinyl chloride-vinyl acetate copolymer; polyvinyl acetate; polyamide; polyimide; celluloses such as triacetyl cellulose and diacetyl cellulose; fluorine-based resin; polyether; polyetheramides; polyether ether ketone; polyphenylene sulfide; polystyrene-based resins such as polystyrene; polycarbonate; polyether sulfone; Acrylic resins, such as polymethyl methacrylate, etc. are mentioned. In addition, the said material can be used individually or in combination of 2 or more types.

Among them, polyester, cellulose, acrylic resin, etc. may be preferable in consideration of the plastic strength, handleability, cost, dimensional stability, optical properties, and the like.

The thickness of the adhesive layer may be from about 10 to about 100 μm, preferably from about 10 to about 50 μm.

And, the adhesive member, according to the FINAT TEST FTM 11 standard, 180degree-peel strength value of 7N/in or more, preferably about 9N/in or more, or about 9 to about 10N/in, have excellent adhesive properties can

Hereinafter, through specific examples of the invention, the operation and effect of the invention will be described in more detail. However, these embodiments are merely presented as an example of the invention, and the scope of the invention is not defined thereby.

<Example>

base resin manufacturing

preparation example One

In a 3L glass reactor equipped with a thermometer, stirrer, dropping funnel, nitrogen gas inlet tube, and reflux condenser, 220 g of water and 10 g of sodium polyoxyethylene aryl ether sulfate with a concentration of 26 wt% of surfactant are placed, and the inside of the reactor is replaced with nitrogen while stirring. Then, the temperature was raised to 80° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, in a 2L beaker, 250 g of butyl acrylate (BA), 538 g of 2-ethylhexyl acrylate (2-EHA), 100 g of methyl methacrylate (MMA), 10 g of acrylic acid (AA), 1 g of polyethyl glycol 400 diacrylate, And 1 g of normal dodecyl mercaptan (n-DDM) was added, and then to 1000 g of the monomer mixture mixed for 30 minutes, 20 g of sodium polyoxyethylene lauryl ether sulfate at a concentration of 26 wt%, sodium alkyldiphenyl oxide disulfo at a concentration of 45 wt% A solution consisting of 10 g of nate solution, 2 g of sodium carbonate, and 300 g of water was added and mixed with a stirrer to prepare a cloudy free emulsion.

5 g of ammonium persulfate having a concentration of 10 wt% was added to the glass reactor and dissolved by stirring for 10 minutes.

In the glass reactor, the pre-emulsion and 140 g of 10 wt% ammonium persulfate were evenly and continuously added for 4 hours, and then 5 g of 10 wt% ammonium persulfate aqueous solution was further added, and then maintained at 80 ° C. for 1 hour. After maintaining the temperature, it was cooled to room temperature to prepare an acrylic emulsion copolymer, a base resin.

The pH was adjusted to 7-8 by adding an aqueous solution of sodium hydroxide at a concentration of 10 wt% to the acrylic emulsion adhesive.

As a result of measuring the prepared base resin by GPC, the weight average molecular weight was 130,000, and the molecular weight distribution was 5.

Manufacture of tackifying resin

preparation example 2

In a 3L glass reactor equipped with a thermometer, stirrer, dropping funnel, nitrogen gas inlet pipe and reflux condenser, 210 g of water and 2 g of sodium polyoxyethylene aryl ether sulfate with a concentration of 26 wt% of a surfactant were placed and the inside of the reactor was replaced with nitrogen while stirring. Then, the temperature was raised to 85° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, 190 g of butyl acrylate (BA), 492 g of methyl methacrylate (MMA), 14 g of acrylic acid (AA), and 21 g of normal dodecyl mercaptan (n-DDM) were added to a 2L beaker, and then the monomer mixture was mixed for 30 minutes. A solution consisting of 7 g of 26 wt% sodium polyoxyethylene lauryl ether sulfate, 14 g of 26 wt% sodium polyoxyethylene aryl ether sulfate solution, 2 g sodium carbonate, and 210 g of water was added and mixed with a stirrer to obtain a cloudy free emulsion was prepared.

5 g of ammonium persulfate having a concentration of 10 wt% was added to the glass reactor and dissolved by stirring for 10 minutes.

In the glass reactor, the pre-emulsion and 90 g of 10 wt% ammonium persulfate were evenly and continuously added for 4 hours, and then 5 g of 10 wt% ammonium persulfate aqueous solution was further added, and then maintained at 85 ° C. and maintained at 85 ° C. for 1 hour. After maintaining the temperature, it was cooled to room temperature to prepare an acrylic emulsion copolymer, gradually imparting resin.

As a result of measuring the prepared tackifying resin by GPC, the weight average molecular weight was 5,000 g/mol, and molecular weight distribution was 1.8.

preparation example 3

In a 3L glass reactor equipped with a thermometer, stirrer, dropping funnel, nitrogen gas inlet pipe and reflux condenser, 210 g of water and 2 g of sodium polyoxyethylene aryl ether sulfate with a concentration of 26 wt% of a surfactant were placed and the inside of the reactor was replaced with nitrogen while stirring. Then, the temperature was raised to 85° C. under a nitrogen atmosphere and maintained for 60 minutes.

Separately, 190 g of butyl acrylate (BA), 492 g of methyl methacrylate (MMA), 14 g of acrylic acid (AA), and 17 g of normal dodecyl mercaptan (n-DDM) were added to a 2L beaker, and then the monomer mixture was mixed for 30 minutes. A solution consisting of 7 g of 26 wt% sodium polyoxyethylene lauryl ether sulfate, 14 g of 26 wt% sodium polyoxyethylene aryl ether sulfate solution, 2 g sodium carbonate, and 210 g of water was added and mixed with a stirrer to obtain a cloudy free emulsion was prepared.

5 g of ammonium persulfate having a concentration of 10 wt% was added to the glass reactor and dissolved by stirring for 10 minutes.

In the glass reactor, the pre-emulsion and 90 g of 10 wt% ammonium persulfate were evenly and continuously added for 4 hours, and then 5 g of 10 wt% ammonium persulfate aqueous solution was further added, and then maintained at 85 ° C. and maintained at 85 ° C. for 1 hour. After maintaining the temperature, it was cooled to room temperature to prepare an acrylic emulsion copolymer, gradually imparting resin.

As a result of measuring the prepared tackifying resin by GPC, the weight average molecular weight was 10,000 g/mol, and molecular weight distribution was 2.0.

preparation example 4

As the rosin ester, a tackifying resin having a weight average molecular weight of 5,000 g/mol and a molecular weight distribution value of 1.5 was prepared.

viscosity measurement

For the base resin and tackifying resin of the preparation example, the viscosity was measured using a Brookfield viscometer (DV-II + Pro Model, Spindle Number LV#3) at 25° C. according to ISO 2555 standards.

The characteristics of the base resin and the tackifying resin are summarized in Table 1 below.

weight average molecular weight
(g/mol) molecular weight distribution viscosity (cps)
(LV#3,12rpm) Preparation Example 1 130,000 5.0 1,100 Preparation Example 2 5,000 1.8 130 Preparation example 3 10,000 2.0 150 Preparation example 4
(Rosin Ester) 5,000 1.5 -

Pressure-sensitive adhesive composition preparation

Based on 100 parts by weight of the base resin, 20 parts by weight of a tackifying resin was mixed (based on solid content), and mixed at a speed of 100 rpm for 2 hours to prepare a pressure-sensitive adhesive composition. The composition of the pressure-sensitive adhesive composition is shown in Table 2 below.

ingredient
(Unit: parts by weight) Example 1 Example 2 Comparative Example 1 Comparative Example 2 base resin Preparation example 1/100 Preparation example 1/100 Preparation example 1/100 Preparation example 1/100 tackifying resin Preparation Example 2/ 20 Preparation example 3/ 20 not added Preparation example 4/ 20

Adhesive member manufacturing

The pressure-sensitive adhesive compositions prepared in Examples and Comparative Examples were respectively applied on silicone-coated release paper, and dried in an oven at 120° C. for 5 minutes so that the adhesive resin coating layer had a thickness of 20 μm. The adhesive resin applied on the silicone release paper was laminated with a PET base film to make an adhesive sheet. The adhesive sheet was cut to a size of 25 mm × 175 mm to prepare an adhesive tape specimen. (Related standards: FINAT Test)

Experimental example

Viscosity measurement

For the darkening adhesive composition, the viscosity was measured using a Brookfield viscometer (DV-II + Pro Model, Spindle Number LV#3) at 25° C. according to ISO 2555 standards.

180 degree peel strength measurement

For the pressure-sensitive adhesive sheet prepared above, in a 180 degree-peel method, the adhesive force was measured. The adhesive member sample was cut to a width of 1 inch and a length of 100 mm, and was measured at room temperature at a speed of 0.3 m/min. (Related standard: FINAT TEST FTM 11)

retention (shear) measurement

Prepare a specimen with a size of 1 inch in width and 0.5 inch in length, attach it so that the stainless steel surface and the attachment surface are 1 inch x 1 inch, and press it by reciprocating it twice with a 2 kg roller. After 10 minutes, the attached sheet was attached to the wall inclined by 2 degrees, a weight of 1 kg was applied to the bottom, and the time for the sheet to fall from the attachment surface was measured in a measurement environment of 23 degrees and 50% humidity. (Related standard: FINAT TEST FTM 8)

color measurement

For the pressure-sensitive adhesive sheet prepared above, with X-rite Color-Eye 7000A equipment, according to the CIELAB 1976 standard, the b* color index value was measured, and the b* color index value of the PET film as the substrate was subtracted, The b* color index value of the composition was obtained. (b1)

After the adhesive sheet was aged at 100° C. for 24 hours, the b* color index value of the composition was obtained by the same method again. (b2)

The rate of change of the color index was measured by the following equation.

[Equation 1]

|b2-b1|

The measured values are summarized in Table 3 below.

unit Example 1 Example 2 Comparative Example 1 Comparative Example 2 peel strength N/in 9.2 8.8 6.9 9.6 retention hour 4 5 14 4 color index rate of change - 0.36 0.36 0.33 1.23

Referring to Table 3 above, the pressure-sensitive adhesive composition according to an embodiment of the present invention has a relatively small b value on the Lab color index while having the same adhesion-related physical properties compared to the case of using a conventional tackifier, It was confirmed that the optical properties could be almost similar to those in the case where the imparting agent was not used, and in particular, even after aging, this value did not change significantly, and it was clearly confirmed that excellent optical transparency could be implemented.

Claims (10)

A)
a1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and
a2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;
a3) a crosslink formed by a crosslinking agent between the repeating units;
a4) a weight average molecular weight value of 80,000 to 250,000 g/mol,
base resin; and
B)
b1) a repeating unit derived from a (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group; and
b2) a repeating unit derived from an unsaturated carboxylic acid monomer having a C1-C14 alkyl group;
b3) a crosslink formed by a crosslinking agent between the repeating units;
b4) a weight average molecular weight value of from 1,000 to 12,000 g/mol;
comprising a tackifying resin;
pressure sensitive adhesive composition.
According to claim 1,
The molecular weight distribution (PDI) of the base resin is 4 to 6,
The molecular weight distribution (PDI) of the tackifying resin is 1 to 3, the pressure-sensitive adhesive composition.
According to claim 1,
The base resin has a viscosity value of 500 to 2,000 cPs measured at 25° C. according to ISO 2555 standards, pressure-sensitive adhesive composition.
According to claim 1,
The pressure-sensitive adhesive composition, wherein the tackifying resin has a viscosity value of 100 to 400 cPs measured at 25° C. according to the ISO 2555 standard.
According to claim 1,
The pressure-sensitive adhesive composition, wherein the tackifying resin is included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the base resin.
According to claim 1,
a1) the (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group used in the base resin is the same as b1) the (meth)acrylic acid ester-based monomer having a C1-C14 alkyl group used in the tackifying resin,
a2) the unsaturated carboxylic acid monomer having a C1-C14 alkyl group used in the base resin is the same as b2) the unsaturated carboxylic acid monomer having a C1-C14 alkyl group used in the tackifying resin,
pressure sensitive adhesive composition.
According to claim 1,
When coated to a thickness of 20 μm, when exposed to 100° C. conditions for 2 hours, the color index change rate is 0.2 to 1, which is represented by the following Equation 1, pressure-sensitive adhesive composition:
[Equation 1]
|b2-b1|
In Equation 1 above,
b1 is the b* color index value, according to CIELAB 1976 criteria, before exposure to 100°C conditions,
b2 is the b* color index value according to the CIELAB 1976 standard after exposure to 100° C. conditions for 2 hours.
write; and
Formed on at least one surface of the substrate, comprising an adhesive layer formed by the pressure-sensitive adhesive composition according to claim 1,
no adhesive.
9. The method of claim 8,
The thickness of the adhesive layer is 10 to 100㎛, the adhesive member.
9. The method of claim 8,
Adhesive member having a 180degree-peel strength value of 7N/in or higher according to FINAT TEST FTM 11 standards.