TWI496864B - Water-whitening resistant pressure sensitive adhesive composition and adhesive article - Google Patents

Description

Emulsified pressure-sensitive adhesive composition with water whitening resistance and use thereof

The present invention relates to an emulsion type pressure-sensitive adhesive having water whitening resistance, which can be applied to the preparation of a clear film label.

Generally used in the market as a label or tape adhesive, which is an acrylic pressure sensitive adhesive, usually divided into solvent type and emulsified type. However, as the environmental protection trend is rising, emulsified acrylic rubber (hereinafter referred to as latex) has become the mainstream, and the transparent film trademark made of latex is applied to the bottle, and its material is polyester (PET), low density. When polyethylene (LDPE), high-density polyethylene (HDPE) or glass, etc., it is desirable to remain transparent and not white under conditions of high humidity for a long time or immersion in water.

In fact, achieving this property is not an easy task because the latex is polymerized with many water-sensitive substances such as emulsifiers, hydrophilic monomers, initiators and buffers. Such materials still have an interface between the emulsion particles when the latex forms a transparent film upon drying. These interfaces provide a path for water molecules to diffuse into the film. As water diffuses into the film, the refractive index at the interface between the emulsion particles becomes larger, resulting in light scattering and whitening, resulting in reduced aesthetics and poor vision.

In order to solve the above problems, the present invention relates to an application of an emulsion type pressure-sensitive adhesive having water whitening resistance to a clear film label.

The invention relates to an emulsion type pressure-sensitive adhesive with water whitening resistance, which can be applied to a clear film label, and the composition thereof comprises: (a) an acrylate monomer having a C _4-12 alkyl group 75~ 95 phr (part per hundred); (b) having a hydrophilic copolymerizable monomer 4 to 20 phr; (c) an α , β unsaturated carboxylic acid group (carboxyl group) copolymerizable monomer 1 to 5 phr; The total amount of +(b)+(c) is 100 phr. Using (d) a reactive surfactant relative to (a) + (b) + (c) = 100 phr, the amount of which is 0.2 to 3.0 phr and (e) a bridging agent, the amount of which is 0.1 to 1.0 phr; Deionized water, initiator and buffer are manufactured by emulsion polymerization.

The emulsified pressure-sensitive adhesive having water whitening resistance obtained by the invention can be used for the transparent film label, and can obtain water whitening resistance, beautiful product appearance and good visual effect.

The invention relates to an emulsion type pressure-sensitive adhesive composition with water whitening resistance, and the composition thereof comprises:

(a) "C _4-12 alkyl acrylate monomer" means butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, decyl acrylate, isodecyl acrylate or lauric acid acrylate. Separately or in combination of two or more. In order to obtain a low glass transition temperature and good adhesion, butyl acrylate and 2-ethylhexyl acrylate are preferably used in an amount ranging from 75 to 95 phr.

(b) "having a hydrophilic copolymerizable monomer" means hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, methyl acrylate, acrylic acid Ethyl acetate, vinyl acetate; it can be used alone or in combination of two or more kinds, and its use amount ranges from 4 to 20 phr.

(c) "A copolymerizable monomer containing an α , β unsaturated carboxylic acid group" means acrylic acid, methacrylic acid, maleic acid, fumaric acid, itacon Itaconic acid, crotonic acid, monoalkyl maleic acid, monoalkyl fumaric acid; alone or in combination of two or more use. Preferred are acrylic acid and methacrylic acid, which are used in an amount ranging from 1 to 5 phr.

Used in the present invention (D) "reactive surfactant", which includes phosphate esters (phosphate ester functionalities), e.g. MAXEMUL ^TM 6112, MAXEMUL ^TM 5011 or MAXEMUL ^TM 5010, produced by the American company Uniquema; and polyoxyl vinyl alkyl phenyl ether sulfate ammonium salt (polyoxyethylene alkylphenyl ether ammonium sulfate), which may be ^{HITENOL BC-10 TM, HITENOL BC} -1025 TM, HITENOL BC-20 TM, HITENOL BC-2020 TM or HITENOL BC-30 ^TM , produced by Japan Dai-Ichi Kogyo Seiyaku company.

(e) "Bracement agent" used in the present invention, which includes allyl methacrylate, dially maleate, Triethylene glycol dimethacrylate, hexanediol diacrylate, 3-glycidoxypropyltrimethoxy silane, ring Glycidyl methacrylate or aceto acetoxy ethyl methacrylate.

An emulsified pressure-sensitive adhesive composition having water whitening resistance, in order to achieve emulsion stability during emulsion polymerization and water-whitening of the final product, different types can be used, and the amount used is 0.2-3.0 phr and ( e) The bridging agent is used in an amount of 0.1 to 1.0 phr. (d) The amount of the reactive surfactant or (e) bridging agent used is based on the total amount of (a) + (b) + (c) = 100 phr.

An emulsion-type pressure-sensitive adhesive composition having water whitening resistance, which can participate in a reaction by at least one initiator, a buffer, and deionized water. The initiator may be potassium persulfate, sodium persulfate, ammonium persulfate, benzoyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile (1, 2-azobisisobutyronitrile) and the like. It is used in an amount of 0.2 to 0.6 phr, relative to the total amount of (a) + (b) + (c) = 100 phr.

The buffer may be sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogencarbonate, sodium phosphate or calcium carbonate. It is used in an amount of from 0.2 to 0.6 phr, relative to the total amount of (a) + (b) + (c) = 100 phr.

An emulsion-type pressure-sensitive adhesive composition having water-resistant whitening, which is subjected to an emulsion polymerization reaction in a reaction tank, and the (a) acrylate monomer having a C _4-12 alkyl group and (b) having a hydrophilicity Polymerized monomer, (c) α , β unsaturated carboxylic acid group (carboxyl group) copolymerizable monomer (d) reactive surfactant and (e) bridging agent mixed, and added as appropriate deionization When water, an initiator and a buffer are present together, the reaction is initiated by heating and heating to form latex particles. The emulsion polymerization temperature is 70-85 ° C, and the reaction time is 5-10 hours. After cooling to room temperature, ammonia water is added to adjust the pH value to 7-8, thereby forming the water-resistant whitening emulsion type pressure-sensitive adhesive product of the present invention. The physical properties are as follows, the solid content is 40-60%, the viscosity is 100-400 cps, and the latex particle size is 100-150 nm.

The following examples are illustrative of the preparation of an emulsion-type pressure-sensitive adhesive composition having water-resistant whitening according to the present invention, and are not intended to limit the scope of protection of the present invention.

[Example 1]

First, 187.2 g of 2-ethylhexyl acrylate monomer [composition (a)], 28.6 g of butyl acrylate monomer [composition (a)], 31.2 g of methyl acrylate [composition (b)], 6.5 g Acrylic monomer [composition (c)], 6.5 g of methacrylic acid monomer [composition (c)], and hexanediol diacrylate [composition (e)] were uniformly stirred to prepare an A solution.

Another 95.4g of deionized water and 26.0g of MAXEMUL ^TM 6112 [Composition (d)] B uniformly stirred to prepare a solution.

Pour the solution A into the solution B and continue to stir to prepare a pre-emulsified C solution.

Another 98.4 g of deionized water was prepared to prepare a D solution.

Another 110.9 g of deionized water, 0.5 g of sodium hydrogencarbonate and 1.3 g of potassium persulfate were uniformly stirred to prepare an E solution.

The D solution was poured into an emulsion polymerization apparatus comprising: a stirrer, a thermometer, a heater, a reflux condenser, a five neck and a one liter round bottom bottle. When heated to 80 ° C, the E solution and the C solution were fed to the emulsion polymerization apparatus for 200 minutes, respectively. The temperature was then raised to 85 ° C, maintained for 90 minutes, then cooled to room temperature, and 3 g of 10% aqueous ammonia was added to adjust the pH to 7.5. The water-resistant whitening emulsion type pressure-sensitive adhesive product of the present invention can be formed, and the physical properties thereof are as follows: the solid content is 53.5%, the viscosity is 100 to 400 cps, and the latex particle diameter is 150 nm.

[Example 2]

First, 187.2 g of 2-ethylhexyl acrylate monomer [composition (a)], 28.6 g of butyl acrylate monomer [composition (a)], 31.2 g of methyl acrylate [composition (b)], 6.5 g Acrylic monomer [composition (c)], 6.5 g methacrylic acid monomer [composition (c)] and 3-glycidoxypropyltrimethoxy silane [composition (e)] uniform Stir to prepare the A solution.

Another 95.4g of deionized water and 26.0g of HITENOL BC-30 ^TM [Composition (d)] B uniformly stirred to prepare a solution.

Pour the solution A into the solution B and continue to stir to prepare a pre-emulsified C solution.

Another 98.4 g of deionized water was prepared to prepare a D solution.

Another 110.9 g of deionized water, 0.5 g of sodium hydrogencarbonate and 1.3 g of potassium persulfate were uniformly stirred to prepare an E solution.

The D solution was poured into an emulsion polymerization apparatus comprising: a stirrer, a thermometer, a heater, a reflux condenser, a five neck and a one liter round bottom bottle. When heated to 80 ° C, the E solution and the C solution were fed to the emulsion polymerization apparatus for 200 minutes, respectively. The temperature was then raised to 85 ° C, maintained for 90 minutes, then cooled to room temperature, and 3 g of 10% aqueous ammonia was added to adjust the pH to 7.5. The water-resistant whitening emulsified pressure-sensitive adhesive product of the present invention can be formed, and the physical properties thereof are as follows: the solid content is 53.5%, the viscosity is 100-400 cps, and the latex particle diameter is 120 nm.

[Comparative Example 1]

First, 187.2 g of 2-ethylhexyl acrylate monomer [composition (a)], 28.6 g of butyl acrylate monomer [composition (a)], 31.2 g of methyl acrylate [composition (b)], 6.5 g Acrylic monomer [composition (c)], 6.5 g methacrylic acid monomer [composition (c)] and 3-glycidoxypropyltrimethoxy silane [composition (e)] uniform Stir to prepare the A solution.

Another 100 g of deionized water was mixed with 1.8 g of polyethylene glycol alkyl phenol ether and 6.0 g of sulfonic acid-dodecyl phenyl ether disodium to prepare a B solution.

Pour the solution A into the solution B and continue to stir to prepare a pre-emulsified C solution.

Another 98.4 g of deionized water was prepared to prepare a D solution.

Another 110.9 g of deionized water, 0.5 g of sodium hydrogencarbonate and 1.3 g of potassium persulfate were uniformly stirred to prepare an E solution.

The D solution was poured into an emulsion polymerization apparatus comprising: a stirrer, a thermometer, a heater, a reflux condenser, a five neck and a one liter round bottom bottle. When heated to 80 ° C, the E solution and the C solution were fed to the emulsion polymerization apparatus for 200 minutes, respectively. The temperature was then raised to 85 ° C, maintained for 90 minutes, cooled to room temperature, and adjusted to pH 7 by adding 3 g of 10% aqueous ammonia. The physical properties produced are as follows, the solid content is 53.6%, and the viscosity is 40 cps. The latex has a particle size of 250 nm.

[Comparative Example 2]

First, 187.2 g of 2-ethylhexyl acrylate monomer [composition (a)], 28.6 g of butyl acrylate monomer [composition (a)], 31.2 g of methyl acrylate [composition (b)], 6.5 g The acrylic monomer [composition (c)] and 6.5 g of the methacrylic acid monomer [composition (c)] were uniformly stirred to prepare an A solution.

Another 100 g of deionized water was mixed with 1.8 g of polyethylene glycol alkyl phenol ether and 6.0 g of sulfonic acid-dodecyl phenyl ether disodium to prepare a B solution.

Pour the solution A into the solution B and continue to stir to prepare a pre-emulsified C solution.

Another 98.4 g of deionized water was prepared to prepare a D solution.

Another 110.9 g of deionized water, 0.5 g of sodium hydrogencarbonate and 1.3 g of potassium persulfate were uniformly stirred to prepare an E solution.

The D solution was poured into an emulsion polymerization apparatus comprising: a stirrer, a thermometer, a heater, a reflux condenser, a five neck and a one liter round bottom bottle. When heated to 80 ° C, the E solution and the C solution were fed to the emulsion polymerization apparatus for 200 minutes, respectively. Then, the temperature was raised to 85 ° C, maintained for 90 minutes, and then cooled to room temperature, and 3 g of 10% ammonia water was added to adjust the pH to 7-8. The physical properties produced were as follows, the solid content was 53.0%, the viscosity was 40 cps, and the latex particle size was 280 nm.

The monomer compositions (a) to (c) used in the examples 1-4 of the present invention and the reactive emulsifiers (d) were compared as shown in Table 1 below.

[Production of test samples]

The emulsified pressure-sensitive adhesives obtained in Examples 1 and 2 and Comparative Examples 1 and 2 of the present invention were respectively coated on one side of a 50 μm polyester (PET) release liner, and the coating layer thickness was 20 μm. Put it into an oven (80 ° C × 5 minutes), and then attach it to a transparent biaxially stretched polypropylene film (BOPP film) to form a transparent film trademark (clear Film label) product.

Water whitening (performance number 1) and glass adhesion (performance number 2) were respectively tested by the following test methods. The performance test results are shown in Table 2 below.

【testing method】

1. Water whitening: (performance number 1)

The sample size is 10cm×10cm, peeling off the release paper, and the rubber surface is directly immersed in the water bath. (25 ° C) immersion time is 24 hours, observe the water whitening level as follows:

◎: Transparent BOPP remains transparent

○: Transparent BOPP becomes transparent pale milk white

×: Transparent BOPP becomes opaque milky white

2. Glass adhesion: (performance number 2)

According to ASTM D-1000 standard.

【Test Results】

The physical properties of the first and second embodiments of the present invention and the comparative examples 1 and 2 are respectively performed according to the foregoing test methods, and the obtained results are shown in Table 2:

It can be seen that the transparent film trademark made by the emulsion-type pressure-sensitive adhesive having water whitening resistance has the effects of water whitening, beautiful product appearance and good vision. The above embodiments are only intended to illustrate the objects, technical contents, features and effects of the present invention, and are not intended to limit the scope of the present invention.

Claims (6)

One kind of water whitening of the emulsion type pressure-sensitive adhesive composition, comprising a: (a) having a C _{4 ~ 12} alkyl acrylate monomers 75 ~ 95phr; (b) having a hydrophilic copolymerizable monomer 4 ~ 20phr; (c) having 1 to 5 phr of a copolymerizable monomer containing an α,β unsaturated carboxyl group; (d) a reactive surfactant of 0.1 to 2.0 phr; (e) a bridging agent of 0.1 to 1.0 phr; (a), (b) and (c) total 100 phr, (d) and (e) are used in relation to (a), (b) and (c) = 100 phr, and an appropriate amount of deionized Water, an initiator and a buffer are obtained by emulsion polymerization; wherein (b) has a hydrophilic copolymerizable monomer, which is hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate , hydroxypropyl methacrylate, methyl acrylate or ethyl acrylate; wherein (d) reactive surfactant is a phosphate or polyoxy vinyl alkyl phenyl ether ammonium sulfate; wherein (e) bridging The agent is allyl methacrylate, dially maleate, triethylene glycol dimethacrylate, hexane Hexanediol diacrylate, 3-glycidoxypropyltrimethoxy silane, glycidyl methacrylate or acetoacetate methacrylate Aceto acetoxy ethyl methacrylate. The emulsified pressure-sensitive adhesive composition for water-whitening according to claim 1, wherein (a) an acrylate monomer having a C _4-12 alkyl group, which is butyl acrylate or 2-ethyl acrylate Hexyl ester, octyl acrylate, decyl acrylate, isodecyl acrylate or lauric acid acrylate. The emulsified pressure-sensitive adhesive composition resistant to water whitening according to claim 1, wherein (c) has a carboxyl group-containing copolymerizable monomer containing α,β, which is acrylic acid, Methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, monoalkyl maleic acid or single Monoalkyl fumaric acid. The water-resistant whitening emulsion pressure-sensitive adhesive composition according to claim 1, wherein the phosphate-based reactive surfactant is MAXEMUL ^TM 6112, MAXEMUL ^TM 5011 or MAXEMUL ^TM 5010 (produced by American Uniquema Co., Ltd.). ). The emulsified pressure-sensitive adhesive composition for water-whitening according to claim 1, wherein the polyoxy vinyl alkyl phenyl ether sulfate-type reactive surfactant is HITENOL BC-10 ^TM , ^{HITENOL BC-1025 TM, HITENOL BC} -20 TM, HITENOL BC-2020 TM or HITENOL BC-30 ^TM (produced by the Japanese company Dai-Ichi Kogyo Seiyaku). The water-resistant whitening emulsified pressure-sensitive adhesive composition according to any one of claims 1 to 5, which is used as a clear film label.