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CURABLE COMPOSITION, PROTECTIVE FILM, OPTICAL ELEMENT, AND LIQUID CRYSTAL DISPLAY DEVICE

20250101225 · 2025-03-27

    Inventors

    Cpc classification

    International classification

    Abstract

    A curable composition is provided. The curable composition comprises a polyorganosiloxane component and a redox catalyst, and is capable of curing a pressure-sensitive adhesive composition without a curing process by heat or energy rays so as to form a pressure-sensitive adhesive layer having appropriate release peel force and residual bond ratio.

    Claims

    1. A curable composition comprising: a polyorganosiloxane component and a redox catalyst, wherein the curable composition is capable of curing an acrylic composition and satisfies an unreacted material content (T.sub.1) according to General Equation 2 of 60% or less, and a cured product of the acrylic composition satisfies a release peel force at 25 C. of 50 gf/inch or less as measured at an interface of a PET film with a peel angle of 180 degrees and a peel rate of 0.3 m/min: TABLE-US-00005 [General Equation 2] T.sub.1 = 100 (W.sub.A W.sub.B)/W.sub.A wherein W.sub.A, an initial weight, is a weight of the cured product of the acrylic composition obtained by curing the acrylic composition at 25 C. for 12 hours or 20 hours, and W.sub.B, a later weight, is a weight of the cured product of the acrylic composition, of which the initial weight has been measured, after storing the cured product of the acrylic composition in an oven at 150 C. for 1 hour.

    2. The curable composition according to claim 1, wherein the polyorganosiloxane component comprises a first polyorganosiloxane component represented by Formula 1: ##STR00006## wherein, R.sub.1, R.sub.7 and R.sub.10 are each independently an alkenyl group of 2 to 20 carbon atoms, an isocyanate group, or an amine group, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.8 and R.sub.9 are each independently an alkyl group of 1 to 20 carbon atoms, an alkenyl group of 2 to 20 carbon atoms, an isocyanate group, or an amine group, and m and n are each independently a number in a range of 1 to 10,000.

    3. The curable composition according to claim 2, wherein the first polyorganosiloxane component is included in an amount of 70 wt % or more relative to the total weight of the polyorganosiloxane component, and the first polyorganosiloxane component has a weight average molecular weight (Mw) in a range of 100,000 to 1,000,000 g/mol.

    4. The curable composition according to claim 1, wherein the polyorganosiloxane component comprises a second polyorganosiloxane component represented by Formula 2: ##STR00007## wherein, R.sub.11 to R.sub.19 are each independently an alkyl group of 1 to 20 carbon atoms, and a and b are each independently a number in a range of 1 to 10,000.

    5. The curable composition according to claim 4, wherein the second polyorganosiloxane component has a weight average molecular weight (Mw) in a range of 1,000 to 50,000 g/mol.

    6. The curable composition according to claim 1, wherein the redox catalyst comprises one or more selected from the group consisting of a naphthenate metal salt, an acetate hydrate metal salt, an alkanoate metal salt, a sulfate hydrate metal salt, an acetylacetonate metal salt, a halogenide metal salt, and an alkoxide metal salt.

    7. The curable composition according to claim 1, wherein the redox catalyst is included in a range of 0.01 to 80 parts by weight relative to 100 parts by weight of the polyorganosiloxane component.

    8. The curable composition according to claim 1, wherein the curable composition further comprises a platinum catalyst.

    9. The curable composition according to claim 2, wherein the redox catalyst is included in a range of 0.01 to 80 parts by weight relative to 100 parts by weight of the first polyorganosiloxane component.

    10. The curable composition according to claim 1, wherein the curable composition forms the cured product of the acrylic composition cured without heat or energy ray irradiation.

    11. The curable composition according to claim 10, wherein the acrylic composition comprises an acrylic compound, and the acrylic compound comprises a (meth)acrylate containing an alkyl group and a (meth)acrylate containing a hydroxyl group.

    12. The curable composition according to claim 1, wherein the cured product of the acrylic composition has a residual bond ratio (A.sub.d) of 80% or more according to General Equation 1 below: Residual bond ratio ( A d ) = A f / A i 100 ( % ) [ General Equation 1 ] wherein A.sub.i is the release peel force at 25 C. of the cured product of the acrylic composition as measured at the interface of the PET (polyethylene terephthalate) film with a peel angle of 180 degrees and a peel rate of 0.3 m/min, and A.sub.f is a release peel force at 25 C. of the cured product of the acrylic composition which is reattached to the interface of the PET film after measuring A.sub.i, as measured with a peel angle of 180 degrees and a peel rate of 0.3 m/min.

    13. A protective film comprising a base film, a pressure-sensitive adhesive layer, and a release layer, wherein the release layer comprises a cured product of the curable composition of claim 1.

    14. An optical element comprising the protective film according to claim 13 attached to one or both sides thereof.

    15. A liquid crystal display device comprising a liquid crystal panel, wherein the optical element according to claim 14 is attached to one or both sides of the liquid crystal panel.

    Description

    MODE FOR INVENTION

    [0138] Hereinafter, the present application will be described with reference to Examples and Comparative Examples, but the scope of the present application is not limited by the contents presented below.

    <Preparation of Curable Composition>

    Example 1

    [0139] As a first polyorganosiloxane component, a compound (Shin-Etsu Silicone's KS-847H) represented by Formula 1A below was used, and the weight average molecular weight (Mw) of the first polyorganosiloxane component was in a range of about 300,000 to 400,000 g/mol.

    ##STR00004##

    [0140] In Formula 1A, m is 1,000 to 2,000 or so, and n is 5 to 20 or so.

    [0141] As a second polyorganosiloxane component, a compound (Shin-Etsu Silicone's X-92-122) represented by Formula 2A below was used, and the weight average molecular weight (Mw) of the second polyorganosiloxane component was in a range of about 8,000 to 12,000 g/mol.

    ##STR00005##

    [0142] In Formula 2A, a is 25 to 45 or so, and b is 25 to 45 or so.

    [0143] The first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), a platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L) and a redox catalyst (Rc, iron (III) acetylacetonate, Sigma-Aldrich) were added to an organic solvent in a weight ratio of 5:0.1:0.15:2 (PS1:PS2:Ptc:Rc) to prepare a curable composition dispersed in the organic solvent.

    [0144] As the organic solvent, a mixture of tetrahydrofuran (THF), methylethyl ketone (MEK), toluene (T) and n-heptane (H) was used, and it was used in an amount sufficient to properly disperse the curable composition.

    Example 2

    [0145] In Example 2, a curable composition dispersed in the organic solvent was prepared in the same manner as in Example 1 above, except that the first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), the platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L) and the redox catalyst (Rc, iron(III) acetylacetonate, Sigma-Aldrich), which were used in Example 1, were added to the organic solvent in a weight ratio of 5:0.1:0.15:0.04 (PS1:PS2:Ptc:Rc).

    Example 3

    [0146] In Example 3, a curable composition dispersed in the organic solvent was prepared in the same manner as in Example 1 above, except that the first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), the platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L) and the redox catalyst (Rc, iron(III) acetylacetonate, Sigma-Aldrich), which were used in Example 1, were added to the organic solvent in a weight ratio of 5:0.1:0.15:0.2 (PS1:PS2:Ptc:Rc).

    Example 4

    [0147] In Example 4, a curable composition dispersed in the organic solvent was prepared in the same manner as in Example 1 above, except that the first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), the platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L) and the redox catalyst (Rc, iron(III) acetylacetonate, Sigma-Aldrich), which were used in Example 1, were added to the organic solvent in a weight ratio of 5:0.1:0.15:1 (PS1:PS2:Ptc:Rc).

    Comparative Example 1

    [0148] In Comparative Example 1, a curable composition dispersed in the organic solvent was prepared in the same manner as in Example 1 above, except that the first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), and the platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L), which were used in Example 1, were added to the organic solvent in a weight ratio of 5:0.1:0.15 (PS1:PS2:Ptc).

    Comparative Example 2

    [0149] In Comparative Example 2, a curable composition dispersed in the organic solvent was prepared in the same manner as in Example 1 above, except that the first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), the platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L) and the redox catalyst (Rc, iron(III) acetylacetonate, Sigma-Aldrich), which were used in Example 1, were added to the organic solvent in a weight ratio of 5:0.1:0.15:5 (PS1:PS2:Ptc:Rc).

    Example 5

    [0150] In Example 5, a curable composition dispersed in the organic solvent was prepared in the same manner as in Example 1 above, except that the first polyorganosiloxane component (PS1), the second polyorganosiloxane component (PS2), the platinum catalyst (Ptc, Shin-Etsu Silicone's PL-50L) and the redox catalyst (Rc, cobalt (III) naphtenate), which were used in Example 1, were added to the organic solvent in a weight ratio of 5:0.1:0.15:2 (PS1:PS2:Ptc:Rc).

    <Production of Protective Film>

    [0151] A protective film was produced by using each of the curable compositions prepared in Examples 1 to 5 and Comparative Examples 1 and 2 above.

    [0152] Each of the curable compositions prepared in Examples 1 to 5 and Comparative Examples 1 and 2 above was applied to one side of each base film, and cured at 150 C. for 3 minutes to form a release layer on the base film. At this time, the thickness of the release layer was about 50 to 80 nm or so, and a PET (polyethylene terephthalate) film having a thickness of about 50 m or so was used as the base film.

    [0153] Hereinafter, an acrylic composition was applied to a thickness of 20 to 30 m or so on the release layer, and the acrylic composition was cured to prepare a protective film having a pressure-sensitive adhesive layer formed thereon. At this time, as the acrylic composition, Acrylic Composition A or Acrylic Composition B was used.

    [0154] Acrylic Composition A above was prepared by mixing an acrylic polymer component (AP), in which 2-ethylhexyl acrylate (2-EHA) and hydroxyethyl acrylate (HEA) were mixed in a weight ratio of 6:4 (2-EHA:HEA) and then polymerized, an acrylic monomer component (AM), in which hydroxyethyl acrylate (HEA) and butyl acrylate (BA) were mixed in a weight ratio of 3:1 (HEA:BA), and 1,6-hexanediol diacrylate (HDD) as a curing agent in a weight ratio of 10:85:1 (AP:AM:HDDA) to obtain a mixture, adding an initiator (cumene hydroperoxide, CHP) to the mixture in an amount of about 1 part by weight relative to the total weight of the mixture, and adding a reducing agent (N,N-dimethyl-p-toluidine, DMPT) thereto in an amount of about 0.6 parts by weight relative to the total weight of the mixture.

    [0155] In addition, Acrylic Composition B above was prepared by mixing an acrylic polymer component (AP), in which 2-ethylhexyl acrylate (2-EHA) and hydroxyethyl acrylate (HEA) were mixed in a weight ratio of 6:4 (2-EHA:HEA) and then polymerized, an acrylic monomer component (AM), in which hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA) were mixed in a weight ratio of 3:1 (HEA:GMA), and a urethane acrylate curing agent (Shin A&C, SUO-1000) as a curing agent in a weight ratio of 10:85:5 (AP:AM:SUO-1000) to obtain a mixture, adding an initiator (methyl ethyl ketone peroxide, MEKP) to the mixture in an amount of about 2 parts by weight relative to the total weight of the mixture, and adding a reducing agent (N,N-dimethyl-p-toluidine, DMPT) thereto in an amount of about 0.6 parts by weight relative to the total weight of the mixture.

    [0156] Table 1 below shows examples of the respective protective films using the curable compositions. Here, the curable composition becomes the release layer of the protective film, and the acrylic composition becomes the pressure-sensitive adhesive layer of the protective film.

    TABLE-US-00001 TABLE 1 Protective Curable Acrylic film composition composition Example 6 Example 1 Acrylic composition A Example 7 Example 2 Acrylic composition A Example 8 Example 3 Acrylic composition A Example 9 Example 4 Acrylic composition A Comparative Comparative Acrylic Example 3 Example 1 composition A Comparative Comparative Acrylic Example 4 Example 2 composition A Example 10 Example 5 Acrylic composition B Comparative Comparative Acrylic Example 5 Example 1 composition B

    <Physical Property Measurement Method>

    Method of Measuring Unreacted Material Content (TML, Total Mass Loss) Ratio

    25 C. Curing Conditions

    [0157] Here, when preparing the protective film, the acrylic composition applied on the release layer was left at 25 C. for 12 hours or 20 hours to form a pressure-sensitive adhesive layer. A portion of the formed pressure-sensitive adhesive layer was appropriately cut, and a PET (polyethylene terephthalate) film was attached to both sides of the cut pressure-sensitive adhesive layer to prepare a measurement sample.

    [0158] The weight (W.sub.A) of the measurement sample was measured and the measurement sample was left in an oven at 150 C. for 1 hour. The weight (W.sub.B) of the measurement sample after being left in the oven was measured. Hereinafter, the unreacted material content (T.sub.1) was measured according to General Equation 2 below.


    T.sub.1=100(W.sub.AW.sub.B)/W.sub.A[General Equation 2]

    [0159] In each of Examples 6 to 9 and Comparative Examples 3 and 4, the unreacted material content (T.sub.1) was measured by leaving the acrylic composition applied on the release layer at 25 C. for 12 hours, and in each of Example 10 and Comparative Example 5, the unreacted material content (T.sub.1) was measured by leaving the acrylic composition applied on the release layer at 25 C. for 20 hours.

    50 C. Curing Conditions

    [0160] Here, when preparing the protective film, the acrylic composition applied on the release layer was left at 50 C. for 20 hours to form a pressure-sensitive adhesive layer. A portion of the formed pressure-sensitive adhesive layer was appropriately cut, and a PET (polyethylene terephthalate) film was attached to both sides of the cut pressure-sensitive adhesive layer to prepare a measurement sample.

    [0161] The weight (W.sub.C) of the measurement sample was measured, and the measurement sample was left in an oven at 150 C. for 1 hour. The weight (W.sub.D) of the measurement sample after being left in the oven was measured. Hereinafter, the unreacted material content (T.sub.2) was measured according to General Equation 3 below.

    [00007] T 2 = 1 0 0 ( W C - W D ) / W C [ General Equation 3 ]

    [0162] The results thereof are shown in Tables 2 and 3 below.

    TABLE-US-00002 TABLE 2 Unreacted material Classification content (T.sub.1, %) Example 6 5.73 Example 7 44.54 Example 8 11.44 Example 9 10.02 Comparative Example 3 89.51 Comparative Example 4 5.24

    TABLE-US-00003 TABLE 3 Unreacted Unreacted material content material content Classification (T.sub.1, %) (T.sub.2, %) Example 10 7.04 5.86 Comparative 94.13 94.18 Example 5

    Method of Measuring Release Peel Force and Residual Bond Ratio

    [0163] A standard tape (TESA, TESA7475) having a PET (polyethylene terephthalate) interface was laminated on the pressure-sensitive adhesive layer of the protective film as prepared above, and stored at 70 C. for 24 hours or so, and then the release peel force (A.sub.i) was measured while peeling the standard tape at 25 C. with a peel angle of 180 degrees and a peel rate of 0.3 m/min using a physical property measuring device (Cheminstruments, AR-1000). Here, the measured release peel force (A.sub.i) was summarized in Table 4 below.

    [0164] In addition, after measuring the release peel force, a standard tape (TESA, TESA7475) having a PET (polyethylene terephthalate) interface was laminated on the pressure-sensitive adhesive layer, and stored at 70 C. for 24 hours or so, and then the later release peel force (A.sub.f) was measured while peeling the standard tape at 25 C. with a peel angle of 180 degrees and a peel rate of 0.3 m/min using a physical property measurement device (Cheminstruments, AR-1000).

    [0165] The residual bond ratio was measured according to General Equation 1 below.

    [00008] Residual bond ratio ( A d ) = A f / A i 100 ( % ) [ General Equation 1 ]

    [0166] In General Equation 1, A.sub.i means the above-described release peel force (A.sub.i), and A.sub.f means the above-described later release peel force (A.sub.f).

    [0167] The results thereof were shown in Table 4 below.

    TABLE-US-00004 TABLE 4 Release peel force Residual bond ratio Classification (gf/inch) (A.sub.d, %) Example 6 31.9 85.97 Example 7 16.5 93.41 Example 8 21.5 91.56 Example 9 22.3 87.32 Comparative 13.5 97.10 Example 3 Comparative 995.4 63.25 Example 4 Example 10 155.3 77.46