Acryl-silicone-based hybrid emulsion adhesive composition and method of preparing the same

Abstract

Disclosed are an acryl-silicone-based hybrid emulsion adhesive composition and a method of preparing the same. Particularly, an acryl-silicone-based hybrid emulsion adhesive composition that includes an acrylic emulsion resin prepared by emulsion polymerization of an acrylic monomer mixture and a seed formed of a reactive silicone resin and thus has high weather resistance and heat resistance and a method of preparing the same are provided.

Claims

1. A composition comprising: a seed formed of a reactive silicone resin, and an acrylic monomer mixture consisting of: i) 60 wt % to 90 wt % of a (meth)acrylic acid ester monomer having a C1-C14 alkyl group; ii) 5 wt % to 35 wt % of at least one monomer selected from the group consisting of allyl esters, vinyl esters, unsaturated acetates, and unsaturated nitriles; iii) 0.5 wt % to 5 wt % of at least one monomer selected from the group consisting of unsaturated carbonic acids and hydroxyl group-containing unsaturated monomers; and iv) 0.1 wt % to 3 wt % of a crosslinking agent, based on a total weight of the acrylic monomer mixture, wherein the reactive silicone resin comprises polyalkylsiloxane having a functional group, wherein the functional group is a hexenyl group, and wherein an amount of the seed is 10 parts by weight to 20 parts by weight based on 100 parts by weight of the acrylic monomer mixture.

2. The composition according to claim 1, wherein the reactive silicone resin has a molecular weight of 500,000 g/mol or less.

3. The composition according to claim 1, wherein the monomer of i) is at least one selected from the group consisting of methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, butyl(meth)acrylate, isobutyl acrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl acrylate, isooctyl acrylate, octyl methacrylate, 2-ethylhexyl(meth)acrylate, isodecyl acrylate, decyl methacrylate, dodecyl methacrylate, isobornyl methacrylate, and lauryl(meth)acrylate.

4. The composition according to claim 1, wherein the monomer of i) comprises a mixture of 20 wt % to 40 wt % of 2-ethylhexyl acrylate and 60 wt % to 80 wt % of butyl acrylate based on a total weight of the (meth)acrylic acid ester monomer.

5. The composition according to claim 1, wherein the at least one monomer of ii) is at least one selected from the group consisting of vinyl acetate, vinyl butyrate, vinyl propionate, vinyl laurate, vinyl pyrrolidone, acrylonitrile, and methacrylonitrile.

6. The composition according to claim 1, wherein the at least one monomer of iii) is at least one selected from the group consisting of acrylic acid, itaconic acid, fumaric acid, crotonic acid, methacrylic acid, hydroxymethyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, hydroxyhexyl(meth)acrylate, hydroxyoctyl(meth)acrylate, hydroxylauryl(meth)acrylate, and hydroxypropyleneglycol(meth)acrylate.

7. The composition according to claim 1, wherein the crosslinking agent has 5 to 15 alkylene oxide groups and is a compound having an acrylate group or a vinyl group.

8. The composition according to claim 7, wherein the crosslinking agent comprises at least one selected from the group consisting of polyethylene glycol diacrylate and polypropylene glycol diacrylate.

9. The composition according to claim 1, wherein the reactive silicone resin has a particle size of 50 nm to 200 nm.

10. A method of preparing an acryl-silicone-based hybrid emulsion adhesive using the composition of claim 1, the method comprising: preparing an emulsion comprising the seed formed of the reactive silicone resin; preparing a pre-emulsion comprising acrylic monomer mixture consisting of, based on a total weight of the acrylic monomer mixture, 60 wt % to 90 wt % of the (meth)acrylic acid ester monomer having a C1-C14 alkyl group, 5 wt % to 35 wt % of the at least one monomer selected from the group consisting of allyl esters, vinyl esters, unsaturated acetates, and unsaturated nitriles, 0.5 wt % to 5 wt % of the at least one monomer selected from the group consisting of unsaturated carbonic acids and hydroxyl group-containing unsaturated monomers, and 0.1 wt % to 3 wt % of the crosslinking agent; and preparing the acryl-silicone-based hybrid emulsion adhesive through polymerization by adding an initiator and the pre-emulsion to the emulsion.

11. The method according to claim 10, wherein the initiator comprises at least one selected from the group consisting of a persulfate of ammonium or an alkali metal, hydrogen peroxide, a peroxide, and a hydroperoxide.

12. An adhesive sheet comprising an adhesive layer formed by polymerizing the composition according to claim 1, and applying the polymerized composition on an adhesive film or sheet.

Description

BEST MODE

(1) Now, the present invention will be described in more detail with reference to the following examples. These examples are provided only for illustration of the present invention and should not be construed as limiting the scope and spirit of the present invention.

Example 1

(2) To a 3 L glass reactor equipped with a thermostat, a stirrer, a dropping funnel, a nitrogen gas injection tube, and a reflux condenser were added 60 g of distilled water and 166 g of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution). Air inside of the reactor was replaced with nitrogen while stirring the resulting solution and the temperature therein was raised to 80 C. in nitrogen atmosphere and maintained for 60 minutes, thereby completing preparation of an emulsion.

(3) Separate from the preparation of the emulsion in the reactor, to prepare a pre-emulsion of acrylic monomers, a solution consisting of a monomer mixture of 500 g of butylacrylate, 330 g of 2-ethylhexylacrylate, 100 g of vinyl acetate, 50 g of acrylonitrile, 20 g of acrylic acid, and 2 g of polyethylene glycol diacrylate, 15 g of a 60% sodium dioctyl sulfosuccinate solution, 50 g of a 30% sodium polyoxyethylene lauryl ether sulfate solution, 2 g of sodium carbonate, 2 g of sodium methylallyl sulfonate, and 270 g of distilled water was added to a beaker and stirred using a stirrer to prepare a milky pre-emulsion.

(4) Subsequently, 5 g of a 10% ammonium persulfate solution was added to the glass reactor containing the emulsion and dissolved therein by stirring for 10 minutes.

(5) The pre-emulsion and 120 g of a 10% ammonium persulfate solution were continuously added in an equal ratio to the glass reactor containing the emulsion for 4 hours, followed by further addition of 5 g of a 10% ammonium persulfate solution, the temperature in the glass reactor was raised to 80 C. for 30 minutes and maintained at 80 C. for 1 hour and cooled to room temperature to prepare an acrylic emulsion resin.

(6) Thereafter, a 28% aqueous ammonia solution was added to the acrylic emulsion resin to adjust pH to 7.5.

Example 2

(7) An acrylic emulsion resin was prepared in the same manner as in Example 1, except that 332 g of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was added to the glass reactor.

Example 3

(8) An acrylic emulsion resin was prepared in the same manner as in Example 1, except that 498 g of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was added to the glass reactor.

Example 4

(9) An acrylic emulsion resin was prepared in the same manner as in Example 1, except that 664 g of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was added to the glass reactor.

Comparative Example 1

(10) An acrylic emulsion resin was prepared in the same manner as in Example 1, except that 200 g of distilled water was added to the glass reactor and vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was not added thereto.

Comparative Example 2

(11) An acrylic emulsion resin was prepared in the same manner as in Example 1, except that 83 g of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was added to the glass reactor.

Comparative Example 3

(12) 100 g (63% solid content) of the acrylic emulsion resin prepared according to Comparative Example 1 was added to a 500 ml beaker, 20 g of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was added thereto, and the resulting solution was stirred for 1 hour to prepare an acryl-silicone-based blend resin.

Comparative Example 4

(13) An acryl-silicone-based blend resin was prepared in the same manner as in Comparative Example 3, except that twice the amount of vinyl terminated polydimethylsiloxane (Mw=5000 g/mol, 30% solution) was used.

Comparative Example 5

(14) 100 g (63% solid content) of the acrylic emulsion resin of Comparative Example 1 was added to a 500 ml beaker, 20 g of silica sol (or colloidal silica, pH: 9.5 to 10.5, 30% solution) was added thereto, and the resulting solution was stirred for 1 hour to prepare an acryl-silica sol blend resin.

Comparative Example 6

(15) An acryl-silica sol blend resin was prepared in the same manner as in Comparative Example 5, except that twice the amount of silica sol (or colloidal silica, pH: 9.5 to 10.5, 30% solution) was used.

Experimental Example 1

(16) Preparation of Paper Label Coated with Adhesive

(17) Each of the resins prepared according to Examples 1 to 4 and Comparative Examples 1 to 6 was coated onto silicone-coated release paper and the coated release paper was dried in an oven at 120 C. for 1 minute to form an adhesive layer having a thickness of 20 m. The resultant release paper was laminated with paper or a film to form a paper or film label and the paper or film label was cut to a size of 25 mm100 mm, thereby completing fabrication of a paper or film label specimen, and adhesive physical properties of each specimen were evaluated. In this regard, glossy paper or thermal paper was used as the paper and PVC, BOPP, PE, or PET was used as the film. In this experiment, the label was prepared using glossy paper and PET as bases.

(18) Adhesion characteristics of the adhesives of Examples 1 to 4 and Comparative Examples 1 to 6 were evaluated using the following methods and evaluation results are shown in Table 1 below. Peel Strength Test: Adhesive strengths of the adhesive label specimens were measured in accordance with FINAT TEST METHOD NO. 2. Accordingly, each adhesive label specimen was attached to a glass plate by reciprocating a 2 kg roller over a surface of the adhesive label specimen at a rate of 300 mm/min and aged at room temperature for 20 minutes, and the aged adhesive label specimen was subjected to 180 peeling at a rate of 300 mm/min using a TA Texture Analyzer. Holding Power Test: Each adhesive label specimen (width: 25 mm) was cut to a size of 25 mm25 mm and attached to an SUS plate (SUS#304, thickness: 1.5 t). In this regard, attachment was performed by reciprocating a 2 kg roller over a surface of the adhesive label specimen at a rate of 300 mm/min, the SUS plate attached by the adhesive label specimen was maintained at room temperature for 30 minutes and then 1 kg of a weight was hung on the adhesive label specimen, and time at which the adhesive label specimen is separated from the SUS plate was measured. In addition, time at which the adhesive label specimen is separated from the SUS plate was measured using the same method at 80. Aging/Hygrothermal Resistance Test: Each adhesive label specimen was exposed to high temperature and high humidity conditions by being placed in an oven at a temperature of 65 C. and a relative humidity of 80%, which are conditions for measuring deterioration of adhesive physical properties, for 4 days, the adhesive label specimen was maintained at room temperature for 1 day, and then peel strength thereof was measured.

(19) TABLE-US-00001 TABLE 1 Paper PET film 180 peel 180 peel strength (N/in) Holding power (hr) strength (N/in) Holding power (hr) normal aging normal 80 C. normal aging normal 80 C. Example 1 15.3 13.5 30 25 10.4 8.2 40 27 Example 2 16.6 14.2 33 23 11.6 10.1 43 33 Example 3 15.5 13.6 37 30 11.3 10.5 42 33 Example 4 14.7 12.7 38 31 12.4 11.2 38 34 Comparative 12.1 6.4 25 2 10.3 8.4 27 3 Example 1 Comparative 11.6 9.3 23 5 12.8 10.4 23 5 Example 2 Comparative 7.5 6.2 10 7 9.5 8.3 17 10 Example 3 Comparative 8.3 7.4 15 8 9.4 8.5 18 13 Example 4 Comparative 7.7 6.3 30 20 8.5 7.1 14 10 Example 5 Comparative 6.2 5.6 33 23 7.8 5.8 15 11 Example 6 * normal: 23 C., RH = 50%, aging: oven 65 C., RH = 80%, 4days

(20) As shown in Table 1 above, it can be confirmed that both the paper and film bases including the resins of Examples 1 to 4 exhibit excellent peel strength and holding power and, in particular, the paper bases exhibit higher peel strength and the film bases exhibit higher holding power, than those of paper and film bases including the resins of Comparative Examples 1 to 6.

(21) Meanwhile, when compared with the paper and film bases including the resins of Comparative Examples 5 and 6 including silica sol, the paper bases including the resins of Examples 1 and 2 have similar holding power while exhibiting significantly enhanced peel strength and the film bases including the resins of Examples 1 and 2 exhibit significantly enhanced peel strength and holding power.

(22) In addition, it can be confirmed that, when compared to the paper and film bases including the resins of Comparative Examples 1 and 2, the film bases including the resins of Examples 1 to 4 exhibit similar peel strength while exhibiting significantly increased holding power and the paper bases including the resins of Examples 1 to 4 exhibit significantly enhanced peel strength and holding power.

(23) That is, it can be confirmed that both the paper and film bases including the resins of Examples 1 to 4 have high peel strength and holding power both at room temperature and under high temperature and high humidity conditions and, accordingly, have excellent weather resistance and heat resistance.

(24) Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

INDUSTRIAL APPLICABILITY

(25) As described above, according to the present invention, an acryl-silicone-based hybrid emulsion adhesive composition is prepared by copolymerizing a reactive silicone resin as a seed and an acrylic monomer mixture through emulsion polymerization and thus exhibits advantages of existing acrylic adhesives and characteristics of silicones, i.e., weather resistance and heat resistance. Thus, a paper or film label including the adhesive composition maintains high peel strength and cohesive strength even at high temperature and high humidity.