Solventless composition and method for preparing the same

Abstract

Provided are a solventless composition and a method of preparing the same. Here, the solventless composition may effectively manufacture a film that is uniform without substantial deviation in thickness and has a large but uniform thickness or an excellent physical property such as thermal resistance during manufacture of a film. In addition, the composition of the present invention does not induce contamination during the manufacture of the film. Furthermore, by preventing gelation or phase separation of components of the composition, the composition capable of manufacturing a substrate film having an excellent physical property such as optical transparency, thermal resistance and dimension stability may be provided.

Claims

1. A solventless composition for manufacturing a film, comprising: a (meth)acrylic polymer component including a (meth)acrylic acid ester-based monomer as a polymerization unit, and having a photoreactive group on a side chain or terminal end thereof; and a monomer component having a glass transition temperature in a range from 20° C. to 100° C., wherein the (meth)acrylic polymer component comprises: a bulk polymerization product of a monomer mixture comprising a (meth)acrylic acid ester-based monomer and a copolymerizable monomer having a first reactive group; and a compound providing the photoreactive group, wherein the compound providing the photoreactive group is not present in the bulk polymerization product of a monomer mixture; wherein the first reactive group is selected from the group consisting of a hydroxyl group, a carboxyl group, an isocyanate group, an amino group and an epoxy group; wherein the (meth)acrylic polymer component has a glass transition temperature in a range from −-50° C. to 0° C.; and wherein as a solventless composition for manufacturing a film in a partially polymerized state, the solventless composition for manufacturing a film provides a cured product having a glass transition temperature of −20 ° C. (250K) or more after curing.

2. The solventless composition for manufacturing a film of claim 1, wherein the photoreactive group is a (meth)acryloyl group.

3. The solventless composition for manufacturing a film of claim 1, wherein the (meth)acrylic acid ester-based monomer comprises a (meth)acrylic acid alkyl ester.

4. The solventless composition for manufacturing a film of claim 1, wherein monomer mixture comprises 70 to 99 parts by weight of the (meth)acrylic acid ester-based monomer and 1 to 30 parts by weight of the copolymerizable monomer having a first reactive group.

5. The solventless composition for manufacturing a film of claim 1, wherein the compound providing a photoreactive group is at least one compound selected from the group consisting of a compound of Formula 1; a compound of Formula 2; a compound of Formula 3; a reaction product of a multifunctional isocyanate compound and a compound of Formula 4; and a reaction product of a multifunctional isocyanate compound, a polyol compound and the compound of Formula 4: ##STR00002## where R.sub.1 is an alkyl group substituted with a (meth)acryloxy group, a (meth)acryloxyalkyl group or an alkenylphenyl group; a (meth)acryloyl group; a (meth)acryloxy group; or an alkenyl group, R.sub.2 is hydrogen or an alkyl group, R.sub.3 is hydrogen or a glycidyl group, R.sub.4 is a (meth)acryloxyalkyl group, R.sub.5 is a halogen atom, R.sub.6 is an alkyl group, n+m+1 is 4, n and m are each independently 1 to 3, and R.sub.7 is a hydroxyalkyl group.

6. The solventless composition for manufacturing a film of claim 1, wherein the compound providing a photoreactive group is comprised at 1 to 200equivalent weight, relative to 100 equivalent weight of the reactive group in the polymerization product.

7. The solventless composition for manufacturing a film of claim 1, wherein the monomer component having a glass transition temperature in a range from 20° C. to 100° C. is isobornyl acrylate, methylmethacrylate or styrene.

8. The solventless composition for manufacturing a film of claim 1, wherein the monomer component having a glass transition temperature in a range from 20° C. to 100° C. is comprised of 35 to 300 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer component.

9. The solventless composition for manufacturing a film of claim 1, further comprising: a multifunctional acrylate or an acrylate-based oligomer.

10. The solventless composition for manufacturing a film of claim 9, wherein the multifunctional acrylate or the acrylate-based oligomer is comprised at 500 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer component.

11. The solventless composition for manufacturing a film of claim 1, further comprising: a photoinitiator.

12. The solventless composition for manufacturing a film of claim 1, which has a viscosity of 500 to 30,000 cps at 25° C.

13. The solventless composition for manufacturing a film of claim 1, which has a gel fraction of 80% to 100% after curing.

14. A method of preparing the solventless composition for manufacturing a film of claim 1, comprising: (a) preparing a bulk polymerization product comprising a (meth)acrylic acid ester-based monomer as a polymerization unit, and also comprising a (meth)acrylic polymer component having a first reactive group on a side chain or terminal end thereof and a monomer component; (b) introducing a photoreactive group to the bulk polymerization product by mixing the bulk polymerization product and a compound having a second reactive group capable of reacting with the first reactive group and the photoreactive group; and (c) mixing further a monomer component having a glass transition temperature in a range from 20° C. to 100° C. with the bulk polymerization product obtained from step (b).

15. The method of preparing a solventless composition for manufacturing a film of claim 14, wherein the operation of preparing a bulk polymerization product comprises partially polymerizing a monomer mixture comprising a (meth)acrylic acid ester-based monomer and a copolymerizable monomer having a first reactive group.

16. A method of manufacturing a film, comprising: coating the solventless composition according to claim 1; and curing the coated composition.

17. A pressure-sensitive adhesive film, comprising: a substrate film; and a pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer formed on the substrate film, wherein the substrate film comprises the composition according to claim 1 in a cured state.

Description

MODES FOR INVENTION

(1) Hereinafter, exemplary embodiments of the present invention will be described in detail. However, the present invention is not limited to the exemplary embodiments disclosed below, but can be implemented in various forms. The exemplary embodiments are provided for complete disclosure of the present invention and to enable those of ordinary skill in the art to embody and practice the present invention.

EXAMPLE 1

(2) Preparation of Solventless Composition

(3) 75 parts by weight of ethylhexyl acrylate (EHA), 20 parts by weight of isobornyl acrylate (IBOA), and 5 parts by weight of hydroxyethyl acrylate (HEA) were input as monomers into a 4-neck glass reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a temperature sensor and a condenser. Subsequently, 120 ppm of n-dodecyl mercaptan (n-DDM) as a chain transfer agent (CTA) and 180 ppm of 2,4-diphenyl-4-methyl-1-pentene (AMSD) were input based on 100 parts by weight of the monomer mixture, and sufficiently mixed at 30° C. for 30 minutes or more while nitrogen was injected into the reaction vessel. Subsequently, a temperature in the reaction vessel was increased to 62° C., and an initiator such as di(2-ethylhexyl)peroxydicarbonate (EHPDC) was input at a concentration of 150 ppm to initiate a reaction. Afterward, when a temperature of a reaction system increased to 80° C. due to heat generated by the reaction, oxygen was input, 20 parts by weight of the monomer mixture (EHA:IBOA:HEA=75:20:5) formed in the same composition as described above was further input based on 100 parts by weight of the monomer mixture initially input thereto, and the temperature was decreased to 30° C. to terminate the reaction, thereby obtaining a first reaction product. The first reaction product included 34% of a high molecular weight product, which had a weight average molecular weight of 600,000 and a glass transition temperature of −43° C.

(4) Subsequently, 1 equivalent weight of 2-methacryloyloxy ethyl isocyanate (MOI) based on 1 equivalent weight of hydroxyethyl acrylate included in the first reaction product and 1 wt % of a catalyst (dibutyl tin dilaurate; DBTDL) based on the weight of the hydroxyethyl acrylate were blended into the first reaction product and reacted at 40° C. for 24 hours to introduce a photoreactive group to a side chain of the polymer in the first reaction product, thereby obtaining a second reaction product.

(5) Then, 50 parts by weight of an isobornyl acrylate monomer (glass transition temperature: 94° C.) and 1 part by weight of a photoinitiator (Irgacure 819), relative to 100 parts by weight of the monomer mixture initially input were blended, thereby obtaining a solventless composition.

(6) Manufacture of Substrate Film

(7) The solventless composition prepared as described above was coated on a carrier film such as poly(ethylene terephthalate) (PET) to have a thickness of 150 nm using a bar coater, and the PET film was laminated again on the coating layer. Afterward, UV rays (1,000 mJ/cm.sup.2) were radiated onto the coating layer using a metal halide lamp while supply of oxygen was interrupted to cure the coating layer, and the PET films on the top and bottom of the coating layer were removed, thereby obtaining a substrate film.

EXAMPLE 2

(8) A process was performed as described in Example 1, except that 100 parts by weight of isobornyl acrylate monomer was blended based on 100 parts by weight of the monomer mixture initially input in Example 1.

EXAMPLE 3

(9) A process was performed as described in Example 1, except that 200 parts by weight of a cyclo hexyl acrylate monomer (glass transition temperature: 18° C.) was blended with respect to 100 parts by weight of the monomer mixture initially input, instead of the isobornyl acrylate monomer in Example 1.

EXAMPLE 4

(10) A process was performed as described in Example 1, except that a reaction amount of MOI was changed into 0.5 equivalent weight during mixing of the secondary reaction product in Example 1.

EXAMPLE 5

(11) A process was performed as described in Example 4, except that a monomer mixture of 73 parts by weight of EHA, 25 parts by weight of IBOA and 2 parts by weight of HEA was used as a monomer mixture of the primary reaction product in Example 4.

EXAMPLE 6

(12) A process was performed as described in Example 5, except that 3 parts by weight of hexanediol diacrylate (HDDA), relative to 100 parts by weight of the composition was further blended into the solventless composition prepared in Example 5.

COMPARATIVE EXAMPLE 1

(13) A process was performed as described in Example 1, except that a solventless composition was prepared by directly mixing an isobornyl acrylate monomer and a photoinitiator without performing an operation of reacting the primary reaction product prepared in Example 1 with MOI.

COMPARATIVE EXAMPLE 2

(14) A process was performed as described in Example 1, except that a solventless composition was prepared by only mixing a photoinitiator without an isobornyl acrylate monomer after the secondary reaction product was prepared in Example 1.

COMPARATIVE EXAMPLE 3

(15) A process was performed as described in Example 1, except that 13 parts by weight of an isobornyl acrylate monomer was blended, relative to 100 parts by weight of the monomer mixture initially input thereto in Example 1.

COMPARATIVE EXAMPLE 4

(16) A process was performed as described in Example 1, except that a monomer mixture of 85 parts by weight of ethylhexyl acrylate (EHA) and 15 parts by weight of hydroxyethyl acrylate (HEA) was used as a monomer mixture of the primary reaction product in Example 1, and 33 parts by weight of an isobornyl acrylate monomer, relative to 100 parts by weight of the monomer mixture initially input was blended.

COMPARATIVE EXAMPLE 5

(17) A process was performed as described in Example 1, except that 50 parts by weight of a 2-ethylhexylacrylate monomer (glass transition temperature: −65° C.) with respect to 100 parts by weight of the monomer mixture initially input was blended, instead of the isobornyl acrylate monomer in Example 1.

COMPARATIVE EXAMPLE 6

(18) A process was performed as described in Comparative Example 1, except that 3 parts by weight of hexanediol diacrylate (HDDA), relative to 100 parts by weight of the composition were further blended into the solventless composition prepared in Comparative Example 1.

COMPARATIVE EXAMPLE 7

(19) Preparation of Solvent-Type Composition

(20) 75 parts by weight of EHA, 20 parts by weight of IBOA and 5 parts by weight of HEA were mixed in an ethyl acetate solvent to have a concentration of the monomer mixture of 40 wt %. Subsequently, 400 ppm of a CTA such as n-DDM was further blended and sufficiently mixed at 30° C. for 30 minutes while nitrogen was injected into a 4-neck glass reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a temperature sensor and a condenser. Afterward, a temperature in the reaction vessel was increased to 62° C., an initiator such as azobisisobutyronitrile (V-60) was input at a concentration of 300 ppm, and polymerization was performed for 5 hours, thereby obtaining a composition.

(21) Manufacture of Substrate Film

(22) A substrate film was manufactured to have a thickness of 150 nm by blending 3 parts by weight of a TDI-based isocyanate curing agent, relative to 100 parts by weight of the solvent-type composition prepared above, coating the resulting mixture on a carrier film, which was a PET film, using a bar coater, and drying the coating layer at 110° C. for 3 minutes.

EXPERIMENTAL EXAMPLE

(23) 1. Measurement of Coatability

(24) The presence of linear patterns or bubbles on the surface of the substrate film manufactured in one of Examples 1 to 6 and Comparative Examples 1 to 7 was observed with the naked eye, and the results are shown in Tables 1 and 2.

(25) ∘: no linear patterns or bubbles (excellent coatability)

(26) x: linear patterns or bubbles (poor coatability)

(27) 2. Measurement of Haze

(28) The substrate films manufactured according to Examples 1 to 6 and Comparative Examples 1 to 7 were observed with the naked eye to determine the presence of a haze, and results are shown in Tables 1 and 2.

(29) ∘: the film was transparent

(30) x: the film was not transparent

(31) 3. Measurement of Glass Transition Temperature (Tg)

(32) A glass transition temperature of each of the substrate films manufactured according to Examples 1 to 6 and Comparative Examples 1 to 7 was measured using a DSC thermogravimetric system, and results are shown in Tables 1 and 2.

(33) 4. Measurement of Gel Fraction

(34) A gel fraction of each of the substrate films manufactured according to Examples 1 to 6 and Comparative Examples 1 to 7 was measured by the following method. The manufactured substrate film was cut into a size of 4 cm×4 cm to measure a weight (A of Equation 1), and immersed in ethyl acetate at room temperature (approximately 25° C.) for 24 hours. Afterward, an insoluble substrate was taken and dried at 150° C. for 30 minutes, and ethyl acetate present in the insoluble content was removed. Then, a weight of the resulting material (B of Equation 1) was measured. Subsequently, the measured weight was assigned to Equation 1, and results are shown in Tables 1 and 2.

(35) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 Monomer EHA 75 75 75 75 73 73 composition of IBOA 20 20 20 20 25 25 primary reaction HEA 5 5 5 5 2 2 product Equivalent weight of 1 1 1 0.5 0.5 0.5 photoreactive group High Tg Kind IBOA IBOA CHA IBOA IBOA IBOA monomer Content 50 100 200 50 50 50 HDDA — — — — — 3 Coatability ∘ ∘ ∘ ∘ ∘ ∘ Haze ∘ ∘ ∘ ∘ ∘ ∘ Gel fraction (%) 95 93 93 93 92 97 Glass transition temperature (° C.) −11 18 −5 −11 −11 −7 EHA: 2-ethylhexylacrylate, IBOA: isobornyl acrylate, CHA: cyclohexyl acrylate, HEA: 2-hydroxyethylacrylate, equivalent weight of photoreactive group: an equivalent weight ratio based on an equivalent weight of a copolymerizable monomer (HEA) having a reactive group, HDDA: parts by weight of hexane diol diacrylate based on 100 parts by weight of the composition

(36) TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 4 5 6 7 Monomer EHA 75 75 75 85 75 75 75 composition of IBOA 20 20 20 — 20 20 20 primary HEA 5 5 5 15 5 5 5 reaction product Equivalent weight of — 1 1 1 1 — — photoreactive group High Tg monomer IBOA — IBOA IBOA — IBOA — (content) (50) (13) (33) (50) Low Tg monomer — — — — EHA — — (content) (50) TDI curing agent — — — — — — 3 HDDA — — — — — 3 — Coatability ∘ ∘ ∘ ∘ ∘ ∘ x Haze x ∘ ∘ ∘ ∘ x ∘ Gel fraction (%) 2 93 93 93 94 78 91 Glass transition temperature −11 −43 −34 −30 −49 −11 −43 (° C.)

(37) As seen from the results of Tables 1 and 2, all of the substrate films of Examples according to the present invention had excellent coatability and film formability, and particularly, even though a film having a large thickness of 150 μm was manufactured, the film had excellent coatability and did not have a haze.

(38) In contrast, in Comparative Examples 1 and 6, since a photoreactive group was not present, a haze was generated in the film due to phase separation in the manufacture of the film, and in Comparative Examples 2 to 5, due to a low glass transition temperature, the film did not have satisfactory physical properties, and could not be used as a substrate film. In addition, in Comparative Example 7, when the composition was coated to a large thickness of 150 μm, it was confirmed that bubbles were generated in the coating layer.

(39) In addition, the substrate film according to Examples had a high gel fraction of 80% or more, thereby having excellent thermal resistance, was optically transparent, and could sufficiently serve as a substrate. However, in the Comparative Examples, since the film could not have a high gel fraction, the thermal resistance was significantly decreased, and thus the film was difficult to use as a substrate, or even though the film had a high gel fraction, due to a low glass transition temperature, the film could not serve as a substrate.

(40) While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.