Preparation method for porous pressure sensitive adhesive article

Abstract

There is provided a preparation method for a porous pressure sensitive adhesive article, a porous pressure sensitive adhesive article, and an abrasive pad. According to an example of the present application, as a porous pressure sensitive adhesive article including a pressure sensitive adhesive layer formed on a porous article, an article having excellent resistance to an external shear strength and to peeling can be provided. Further, according to the above method, the porous article can be attached firmly to a large-area adherent. In an example, the porous article may be an abrasive pad.

Claims

1. A preparation method for a porous pressure sensitive adhesive article, comprising: forming a hot melt adhesive layer on an adhered surface on which pores are formed; and forming a pressure sensitive adhesive layer on the hot melt adhesive layer, wherein the pressure sensitive adhesive layer comprises an acryl polymer having a carboxyl group, wherein the acryl polymer comprises a (meth)acrylic acid ester monomer in an amount of 75 parts by weight to 99 parts by weight, and a carboxyl group-containing copolymeric monomer in an amount of 1 part by weight to 15 parts by weight as polymerization units, wherein the pressure sensitive adhesive layer has a gel fraction of 30% or less, and wherein the adhered surface is a surface of an abrasive pad.

2. The preparation method of claim 1, wherein a ratio of an area where the pores are formed on the adhered surface is 5% or more with respect to the whole adhered surface area.

3. The preparation method of claim 1, wherein the hot melt adhesive layer is formed by using a urethane hot melt adhesive agent, a polyamide hot melt adhesive agent, a polyester hot melt adhesive agent, a polyolefin hot melt adhesive agent, a polycaprolactame hot melt adhesive agent, or a silicon hot melt adhesive agent.

4. The preparation method of claim 1, wherein the hot melt adhesive layer is formed by forming a hot melt adhesive agent on the adhered surface and maintaining the hot melt adhesive agent at 60 C. to 100 C. for 30 minutes to 300 minutes.

5. The preparation method of claim 1, wherein the acryl polymer has a weight average molecular weight of 300,000 to 2,500,000.

6. The preparation method of claim 1, wherein the acryl polymer is in a cross-linked state by a multifunctional cross-linking agent.

7. The preparation method of claim 1, wherein the pressure sensitive adhesive layer further comprises a tackifier.

8. The preparation method of claim 7, wherein the tackifier includes a rosin ester-based tackifier or a styrene-based tackifier.

9. The preparation method of claim 7, wherein the pressure sensitive adhesive layer comprises the tackifier in an amount of 1 part by weight to 25 parts by weight with respect to 100 parts by weight of the acryl polymer.

Description

DESCRIPTION OF DRAWINGS

(1) FIGS. 1 and 2 are cross-sectional views illustrating an example of a porous pressure sensitive adhesive article.

(2) FIG. 3 is a photograph of fibrils formed on an interface between a hot melt adhesive layer and a pressure sensitive adhesive layer of a porous pressure sensitive adhesive article prepared in an Example.

BEST MODE

(3) Hereinafter, the above-descried method will be explained in detail with reference to Examples and Comparative Examples, but the scope of the above method is not limited to the Examples provided below.

(4) Properties of Examples and Comparative Examples were evaluated by the following method.

(5) 1. Measurement of Molecular Weight

(6) A molecular weight of an acryl polymer was measured by using a GPC under the following conditions. Measurement results were converted to prepare a calibration curve by using standard polystyrenes of Agilent system.

(7) <Weight Average Molecular Weight Measurement Conditions>

(8) Measurement apparatus: Agilent GPC (Agilent 1200 series, U.S.A.) Column: Two-connected PL Mixed B Column temperature: 40 C. Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min Concentration: 2 mg/mL (100 L injection)

(9) 2. Measurement of Gel Fraction

(10) About 0.3 g of a pressure sensitive adhesive agent prepared in an Example or Comparative Example was collected and put into a 200 mesh stainless steel sieve. Then, the pressure sensitive adhesive agent was deposited in ethyl acetate and kept in a darkroom at room temperature for 3 days. Thereafter, the adhesive agent (insolubles) which was not dissolved in the ethyl acetate was collected and dried in an oven at 70 C. for 4 hours. Then, a weight (a dry weight in units of g) thereof was measured and substituted into General Formula 1 below so as to measure a gel fraction.
Gel fraction (%)=(Measured dry weight)/0.3100[General Formula 1]

(11) 3. Measurement of Peeling Strength

(12) A peeling strength was evaluated after a porous pressure sensitive adhesive article prepared in an Example or Comparative Example was maintained at room temperature for 3 days. The peeling strength was measured by peeling an outermost PET film of the porous pressure sensitive adhesive article of an Example or Comparative Example at a peeling rate of 5 mm/sec at a peeling angle of 180 degrees by using a tensile tester at room temperature.

(13) 4. Measurement of Shear Resistance Strength

(14) After a porous pressure sensitive adhesive article prepared in an Example or Comparative Example was cut out into a circle having a diameter of about 20 cm, an abrasive pad of the porous pressure sensitive adhesive article was rotated at 200 rpm for 3 days while being in contact with glass. It was observed whether the outermost PET film of the porous pressure sensitive adhesive article separated from the pad or whether a gap formed therebetween, and evaluation thereof was conducted based on the following criteria.

(15) <Shear Resistance Strength Evaluation Criteria>

(16) : A case where peeling of the abrasive pad from the PET film or a gap therebetween were not observed

(17) X: A case where peeling of the abrasive pad from the PET film or a gap therebetween were observed

Preparation Example 1

Preparation of Acryl Pressure Sensitive Adhesive Agent (A)

(18) 2-ethylhexyl acrylate in an amount of 80 parts by weight, butyl acrylate in an amount of 17 parts by weight, and an acrylic acid in an amount of 3 parts by weight were put into a reactor in which a nitrogen gas was refluxed and a cooling device was provided so as to easily control a temperature, and ethyl acetate (EAc) was added thereto as a solvent. Then, the reactor was purged with the nitrogen gas for 20 minutes in order to remove oxygen and a temperature was maintained at 60 C. While a mixture was uniformalized, azobisisobutyronitrile (AIBN) diluted in ethyl acetate at an adequate concentration was added thereto as a reaction initiator and reacted for 8 hours, thereby preparing an acryl polymer (A) having a molecular weight of 600,000. A tetrafunctional epoxy-based cross-linking agent (Tetrad X, Mitsubishi Gas Chemical Company) was input in an amount of 1.0 part by weight with respect to 100 parts by weight of the prepared polymer (A) so as to prepare a pressure sensitive adhesive composition (A). The prepared pressure sensitive adhesive composition (A) was coated on one side of a PET (poly(ethylene terephthalate)) film having a thickness of about 100 m so as to have a thickness of about 50 m after a dry process and aged under adequate conditions, thereby preparing an acryl pressure sensitive adhesive agent (A). The prepared pressure sensitive adhesive agent (A) had a gel fraction of about 90%.

Preparation Examples 2 to 6

Preparation of Acryl Pressure Sensitive Adhesive Agents (A) to (F)

(19) Acryl pressure sensitive adhesive agents were prepared in the same manner as Preparation Example 1 except that the composition of monomers was changed as shown in Table 1 below during a preparation process of an acryl polymer, and reaction conditions or ratios of cross-linking agents were adjusted so as to change molecular weights of polymers and gel fractions of pressure sensitive adhesive agents as shown in Table 1.

(20) However, in Preparation Example 3, a tolylene diisocyanate addition of trimethylolpropane was used as an isocyanate cross-linking agent instead of the epoxy-based cross-linking agent to prepare an pressure sensitive adhesive agent (C) having a gel content as required.

(21) Further, in Preparation Examples 5 and 6, tackifiers listed in Table 1 were added to pressure sensitive adhesive compositions and then stirred at about 200 rpm for about 20 minutes. The resultant pressure sensitive adhesive compositions were used to prepare pressure sensitive adhesive agents (E) and (F).

(22) TABLE-US-00001 TABLE 1 Preparation Example 1 2 3 4 5 6 (A) (B) (C) (D) (E) (F) Composition of EHA 80 80 80 80 80 monomers BA 17 17 13 97 17 17 (Content unit: AA 3 3 3 3 3 Parts by weight) HEA 7 Molecular weight of polymer 60 60 60 75 60 60 (unit: ten thousand) Rosin ester-based tackifier 25 Styrene-based tackifier 3 Gel fraction of pressure sensitive 90 15 15 22 15 15 adhesive agent (unit: %) EHA: 2-ethylhexyl acrylate BA: butyl acrylate AA: acrylic acid HEA: 2-hydroxyethyl acrylate

Example 1

(23) A urethane-based hot melt adhesive agent was coated to a thickness of about 20 m on a release-treated surface of a release-treated PET film. The coated adhesive agent was laminated on a urethane-based abrasive pad typically used for abrading glass for display devices. Then, the abrasive pad on which the adhesive agent was laminated was kept in an oven at 80 C. for about 2 hours so as to form a hot melt adhesive layer. Thereafter, the release-treated PET film was peeled from the formed hot melt adhesive layer and an acryl pressure sensitive adhesive agent (B) prepared in Preparation Example 2 was coated to a thickness of 50 m on one side of the peeling surface as an pressure sensitive adhesive surface of the PET film, and then the pressure sensitive adhesive surface of the PET film was laminated by a laminator, thereby preparing an abrasive pad as a porous pressure sensitive adhesive article attached to the PET film. FIG. 3 is a photograph of fibrils formed on an interface between a hot melt adhesive layer and a pressure sensitive adhesive layer of the porous pressure sensitive adhesive article prepared in Example 1 when the PET film was peeled from the porous pressure sensitive adhesive article.

Example 2

(24) A porous pressure sensitive adhesive article was prepared in the same manner as Example 1 except that a pressure sensitive adhesive agent (D) was used instead of the pressure sensitive adhesive agent (B).

Example 3

(25) A porous pressure sensitive adhesive article was prepared in the same manner as Example 1 except that a polyamide-based hot melt adhesive agent was used as the hot melt adhesive agent.

Example 4

(26) A porous pressure sensitive adhesive article was prepared in the same manner as Example 1 except that a pressure sensitive adhesive agent (E) was used instead of the pressure sensitive adhesive agent (B).

Example 5

(27) A porous pressure sensitive adhesive article was prepared in the same manner as Example 1 except that a pressure sensitive adhesive agent (F) was used instead of the pressure sensitive adhesive agent (B).

Example 6

(28) A porous pressure sensitive adhesive article was prepared in the same manner as Example 1 except that a pressure sensitive adhesive agent (A) was used instead of the pressure sensitive adhesive agent (B).

Example 7

(29) A porous pressure sensitive adhesive article was prepared in the same manner as Example 1 except that a pressure sensitive adhesive agent (C) was used instead of the pressure sensitive adhesive agent (B).

Comparative Example 1

(30) A porous pressure sensitive adhesive article attached to a PET film was prepared by laminating a pressure sensitive adhesive (B) surface of the PET film whose one side was coated with the pressure sensitive adhesive agent (B) prepared in Preparation Example 1 to a thickness of 50 m without forming a hot melt adhesive layer on one side of the same abrasive pad as used in Example 1.

Comparative Example 2

(31) The same hot melt adhesive agent as used in Example 1 was coated on one side of a release-treated PET film in the same manner as Example 1, and the hot melt adhesive agent coated on the release-treated PET film was laminated on the same abrasive pad as used in Example 1 by a laminator. Then, the release-treated PET film was peeled, and only a PET film was attached to the peeling surface without a pressure sensitive adhesive layer and maintained in an oven at 80 C. for 2 hours, thereby preparing a porous pressure sensitive adhesive article with the PET film attached.

(32) Properties of the Examples and Comparative Examples were compared as shown in Table 2 below.

(33) TABLE-US-00002 TABLE 2 Comparative Example Example 1 2 3 4 5 6 7 1 2 Peeling 3500 3400 3200 4500 4700 1800 2100 Failed Failed strength (unit: g/inch) Shear X X resistance strength Fibril Observed Observed Observed Observed Observed Not Not observed observed Failed: An adhesive strength between an abrasive pad and a PET film was too small to be measured.

DESCRIPTION OF MAIN REFERENCE NUMERALS OF DRAWINGS

(34) 10: Porous pressure sensitive adhesive article 20: Porous article 21: Pores 30: Hot melt adhesive layer 40: Pressure sensitive adhesive layer 50: Fibril