Curable silicone composition, cured product thereof, and optical display

Abstract

Disclosed is a curable silicone composition. The composition comprises: (A) an organopolysiloxane having at least two alkenyl groups and at least one aryl group in each molecule; (B) a polyoxyalkylene compound represented by the general formula: XO(C.sub.2H.sub.4O).sub.p(C.sub.nH.sub.2nO).sub.q(YO).sub.rX, wherein, each X represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an acryl group, or a methacryl group, provided that at least one X in each molecule is the alkenyl group, the acryl group, or the methacryl group, Y represents a divalent hydrocarbon group, n represents an integer of 3 to 6, p and q are integers satisfying: 2p100 and 0q50, and r represents 0 or 1; (C) an organopolysiloxane having at least two silicon bonded hydrogen atoms in each molecule; and (D) a catalyst for a hydrosilylation reaction. The composition forms a cured product having improved properties.

Claims

1. A curable silicone composition comprising: (A) an organopolysiloxane having at least two alkenyl groups with 2 to 12 carbon atoms and at least one aryl group with 6 to 20 carbon atoms in each molecule; (B) a polyoxyalkylene compound represented by the general formula:
XO(C.sub.2H.sub.4O).sub.p(C.sub.nH.sub.2nO).sub.q(YO).sub.rX wherein, each X represents the same or different hydrogen atom, alkyl group with 1 to 12 carbon atoms, alkenyl group with 1 to 12 carbon atoms, aryl group with 6 to 20 carbon atoms, acryl group, or methacryl group, provided that at least one X in each molecule is the alkenyl group, the acryl group, or the methacryl group, Y represents a divalent hydrocarbon group with 2 to 20 carbon atoms, n represents an integer of 3 to 6, p and q are integers satisfying: 2p100 and 0q50, and r represents 0 or 1; (C) an organopolysiloxane having at least two silicon bonded hydrogen atoms in each molecule; (D) a catalyst for a hydrosilylation reaction; and (E) a diorganosiloxane oligomer having at least one aryl group with 6 to 20 carbon atoms and not having a hydrosilylation reactive functional group in each molecule, in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the total of components (A) to (D); wherein the content of component (B) is an amount such that the total amount of units represented by the formula: C.sub.2H.sub.4O in component (B) is 0.4 to 40 mass % with respect to the total amount of components (A) to (D); wherein the content of component (C) is an amount such that the silicon bonded hydrogen atoms in component (C) are 0.1 to 5 mol per 1 mol of the total aliphatic unsaturated carbon-carbon bonds in components (A) and (B); wherein the content of component (D) is a sufficient amount to promote curing of the composition; and wherein component (E) is a diorganosiloxane oligomer represented by the general formula: ##STR00004## where each R is the same or different monovalent hydrocarbon group with 1 to 12 carbon atoms not having an aliphatic unsaturated bond, provided that at least one R in each molecule is an aryl group with 6 to 20 carbon atoms, while x is an integer of 3 to 10.

2. The curable silicone composition according to claim 1, wherein the viscosity at 25 C. of component (A) is 50 to 100,000 mPa.Math.s.

3. The curable liquid silicone composition according to claim 1, wherein the content of aryl groups with respect to all silicon atom bonded organic groups in component (A) is at least 30 mol %.

4. The curable silicone composition according to claim 1, wherein the viscosity at 25 C. of component (C) is 1 to 10,000 mPa.Math.s.

5. The curable silicone composition according to claim 1, wherein the viscosity at 25 C. of component (E) is 1 to 500 mPa.Math.s.

6. The curable silicone composition according to claim 1, wherein component (E) is a diorganosiloxane oligomer having an aryl group of 5 to 60 mol % of all Rs in each molecule.

7. The curable silicone composition according to claim 1, which is an optical adhesive or pressure sensitive adhesive.

8. A cured product obtained by curing the curable silicone composition according to claim 1.

9. A laminate comprising: the cured product according to claim 8; and an optical member.

10. An optical display obtained using the curable silicone composition according to claim 1.

11. A laminate comprising: a cured product; and an optical member; wherein the cured product is obtained by curing a curable silicone composition; and wherein the curable silicone composition comprises: (A) an organopolysiloxane having at least two alkenyl groups with 2 to 12 carbon atoms and at least one aryl group with 6 to 20 carbon atoms in each molecule; (B) a polyoxyalkylene compound represented by the general formula:
XO(C.sub.2H.sub.4O).sub.p(C.sub.nH.sub.2nO).sub.q(YO).sub.rX wherein, each X represents the same or different hydrogen atom, alkyl group with 1 to 12 carbon atoms, alkenyl group with 1 to 12 carbon atoms, aryl group with 6 to 20 carbon atoms, acryl group, or methacryl group, provided that at least one X in each molecule is the alkenyl group, the acryl group, or the methacryl group, Y represents a divalent hydrocarbon group with 2 to 20 carbon atoms, n represents an integer of 3 to 6, p and q are integers satisfying: 2p100 and 0q50, and r represents 0 or 1; (C) an organopolysiloxane having at least two silicon bonded hydrogen atoms in each molecule; and (D) a catalyst for a hydrosilylation reaction; wherein the content of component (B) is an amount such that the total amount of units represented by the formula: C.sub.2H.sub.4O in component (B) is 0.4 to 40 mass % with respect to the total amount of components (A) to (D); wherein the content of component (C) is an amount such that the silicon bonded hydrogen atoms in component (C) are 0.1 to 5 mol per 1 mol of the total aliphatic unsaturated carbon-carbon bonds in components (A) and (B); and wherein the content of component (D) is a sufficient amount to promote curing of the composition.

12. An optical display obtained using a curable silicone composition, wherein the curable silicone composition comprises: (A) an organopolysiloxane having at least two alkenyl groups with 2 to 12 carbon atoms and at least one aryl group with 6 to 20 carbon atoms in each molecule; (B) a polyoxyalkylene compound represented by the general formula:
XO(C.sub.2H.sub.4O).sub.p(C.sub.nH.sub.2nO).sub.q(YO).sub.rX wherein, each X represents the same or different hydrogen atom, alkyl group with 1 to 12 carbon atoms, alkenyl group with 1 to 12 carbon atoms, aryl group with 6 to 20 carbon atoms, acryl group, or methacryl group, provided that at least one X in each molecule is the alkenyl group, the acryl group, or the methacryl group, Y represents a divalent hydrocarbon group with 2 to 20 carbon atoms, n represents an integer of 3 to 6, p and q are integers satisfying: 2p100 and 0q50, and r represents 0 or 1; (C) an organopolysiloxane having at least two silicon bonded hydrogen atoms in each molecule; and (D) a catalyst for a hydrosilylation reaction; wherein the content of component (B) is an amount such that the total amount of units represented by the formula: C.sub.2H.sub.4O in component (B) is 0.4 to 40 mass % with respect to the total amount of components (A) to (D); wherein the content of component (C) is an amount such that the silicon bonded hydrogen atoms in component (C) are 0.1 to 5 mol per 1 mol of the total aliphatic unsaturated carbon-carbon bonds in components (A) and (B); and wherein the content of component (D) is a sufficient amount to promote curing of the composition.

Description

EXAMPLES

(1) The curable silicone composition, cured product thereof, and display device according to the present invention will be described in detail by way of examples. Note that in the formulae, Me, Vi, Ph, and Gly represent a methyl group, vinyl group, phenyl group, and 3-glycidoxypropyl group, respectively. Furthermore, in the examples, measurements and evaluations were carried out as described below.

(2) [Viscosity of Organopolysiloxane and Curable Silicone Composition]

(3) The viscosity (mPa.Math.s) at 25 C. was measured using a rotary viscometer (E type viscometer VISCONIC EMD produced by TOKIMEC CORPORATION).

(4) [Refractive Index of Organopolysiloxane and Cured Product]

(5) Using a refractometer (RX-7000a produced by Atago Co., Ltd.; wavelength of light source: 589 nm), the refractive index at 25 C. was measured.

(6) [Curing Properties of Curable Silicone Composition]

(7) A test piece filled with a curable silicone composition was heated in an oven at 40 C. so that the dimensions of the cured silicone cured product were a length of 25 mmwidth of 25 mmthickness of 200 m between the two glass plates (length of 75 mmwidth of 25 mmthickness of 2 mm). The test piece was removed every 15 minutes, the properties of the curable silicone composition were observed, and the curability thereof was evaluated by the time (minutes) until the composition lost fluidity.

(8) [Transparency of Cured Product]

(9) A curable silicone composition was filled and heated in an oven at 40 C. for one hour so that the dimensions of the cured silicone cured product were a length of 25 mmwidth of 25 mmthickness of 200 m between the two glass plates (length of 75 mmwidth of 25 mmthickness of 2 mm), to cure the abovementioned composition so as to produce a test piece containing a cured product sandwiched between two glass plates. Regarding this test piece, the transmittance of the cured product was measured using a spectrophotometer (UV-3100PC produced by Shimadzu Corporation; wavelength: 450 nm).

(10) [Cloudiness of Cured Product]

(11) A curable silicone composition was filled and heated in an oven at 40 C. for one hour so that the dimensions of the cured silicone cured product were a length of 25 mmwidth of 25 mmthickness of 200 m between the two glass plates (length of 75 mmwidth of 25 mmthickness of 2 mm), to cure the abovementioned composition so as to produce a test piece containing a cured product sandwiched between two glass plates. After this test sample was left to stand for 16 hours in a high temperature and high humidity environment of 85 C. and 85% RH, the clouding of the cured product was measured in accordance with the method stipulated in ASTM D1003.

(12) [Mode of Adhesion of Cured Product]

(13) A curable silicone composition was filled and heated in an oven at 40 C. for one hour so that the dimensions of the cured silicone cured product were a length of 25 mmwidth of 25 mmthickness of 200 m between the two glass plates (length of 75 mmwidth of 25 mmthickness of 2 mm), to cure the abovementioned composition so as to produce a test piece containing a cured product sandwiched between two glass plates. This test piece was subjected to shear adhesion testing in accordance with the method stipulated in JIS K6850 to observe the mode of adhesion of the cured product.

Examples 1 to 5 and Comparative Examples 1 to 2

(14) The curable silicone compositions were prepared at the compositions (parts by mass) shown in Table 1 using the following components. Note that the liquid curable silicone composition was prepared in portions of liquids A and B for mixing at a mass ratio of 1:1. That is, the following components (b-1), (b-3), (d-1), and (e-1) were blended in liquid A, the following components (c-1) and (c-2) were blended in liquid B, and liquids A and B were dispensed in components (a-1), (a-2), and (b-2). The thus prepared liquids A and B were mixed at a mass ratio of 1:1 using a static mixer to prepare a curable silicone composition. Note that in the table, the ratio of the SiH/alkenyl groups represents the value of the total number of moles of silicon atom bonded hydrogen atoms in components (c-1) to (c-2) to 1 mol of the total of vinyl groups in components (a-1) to (a-2) and methallyl groups in components (b-1) to (b-2) in the composition. Moreover, in the table, the proportion of EO represents the ratio of the number of moles of units represented by the formula: C.sub.2H.sub.4O with respect to the total number of moles of units represented by the formula: C.sub.2H.sub.4O and units represented by the formula: CH.sub.2CH(Me)O in components (b-1) to (b-3). Moreover, in the table, the EO content represents the proportion (mass %) of the total amount of units represented by formula: C.sub.2H.sub.4O in components (b-1) to (b-3) with respect to the total amount of components (a-1) to (a-2), (b-1) to (b-3), (c-1) to (c-2), and (d-1).

(15) The following components were used as component (A). (a-1): a methylphenylpolysiloxane blocked with dimethylvinylsiloxy groups at both molecular chain terminals and having a viscosity of 3,000 mPa.Math.s (content of phenyl groups: 45 mol %, refractive index: 1.53) (a-2): a methylphenylpolysiloxane blocked with dimethylvinylsiloxy groups at both molecular chain terminals and having a viscosity of 40,000 mPa.Math.s (content of phenyl groups: 48 mol %, refractive index: 1.54) (a-3): a methylphenylpolysiloxane blocked with dimethylvinylsiloxy groups at both molecular chain terminals and having a viscosity of 2,800 mPa.Math.s (content of phenyl groups: 43 mol %, refractive index: 1.53)

(16) The following components were used as component (B). (b-1): a polyoxyethylene blocked with dimetallyl groups at both molecular chain terminals and represented by the average unit formula:
CH.sub.2C(Me)CH.sub.2O(C.sub.2H.sub.4O).sub.14CH.sub.2C(Me)=CH.sub.2 (b-2): a random copolymer of polyoxyethylene and polyoxypropylene blocked with dimetallyl groups at both molecular chain terminals and represented by the average unit formula:
CH.sub.2C(Me)CH.sub.2O(C.sub.2H.sub.4O).sub.34[CH.sub.2CH(Me)O].sub.26CH.sub.2C(Me)=CH.sub.2 (b-3): a polyethylene glycol mono-4-octylphenyl ether represented by the average unit formula:
HO(C.sub.2H.sub.4O).sub.10-para-C.sub.6H.sub.4C.sub.8H.sub.17 (b-4): a polyoxypropylene blocked with dimetallyl groups at both molecular chain terminals and represented by the average unit formula:
CH.sub.2C(Me)CH.sub.2O[CH.sub.2CH(Me)O].sub.21CH.sub.2C(Me)=CH.sub.2

(17) The following components were used as component (C). (c-1): 1,1,5,5-tetramethyl-3,3-diphenyl trisiloxane (c-2): an organopolysiloxane represented by the average unit formula:
(Me.sub.2HSiO.sub.1/2).sub.0.6(PhSiO.sub.3/2).sub.0.4
having a viscosity of 20 mPa.Math.s

(18) The following component was used as component (D). (d-1): a phenyltrisdimethylvinylsiloxysilane solution of a platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex having a platinum content of 0.49% by mass.

(19) The following component was used as component (E). (e-1): a mixture of methylphenyl cyclosiloxane represented by the formula:

(20) ##STR00003##
(wherein, x is an integer of 3 to 10) having a viscosity of 50 mPa.Math.s

(21) The following components were used as an adhesion imparting agent. (f-1): an organopolysiloxane represented by the average unit formula:
(Me.sub.2ViSiO.sub.1/2).sub.0.18(GlyMeSiO.sub.2/2).sub.0.29(PhSiO.sub.3/2).sub.0.53
and represented by the average composition formula:
Gly.sub.0.29Me.sub.0.65Vi.sub.0.8Ph.sub.0.53SiO.sub.1.18
having a viscosity of 18,000 mPas (f-2): a silicon-containing compound represented by the formula:
(MeO).sub.3SiC.sub.6H.sub.12Si(OMe).sub.3

(22) TABLE-US-00001 TABLE 1 Comparative Example Present invention Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 1 Example 2 Curable silicone (a-1) 43.9 42.5 41.3 45.8 45.1 composition (a-2) 43.9 42.5 41.3 67.3 62.6 45.8 45.1 (parts by mass) (b-1) 3.0 5.0 7.0 1.0 5.0 (b-2) 25.1 25.1 (b-3) 3.0 (c-1) 6.1 6.7 7.1 2.2 2.6 5.3 1.9 (c-2) 1.0 1.1 1.1 2.0 2.3 0.9 2.6 (d-1) 0.2 0.2 0.2 0.3 0.3 0.2 0.2 (f-1) 2.0 2.0 2.0 2.0 2.0 2.0 2.0 (f-2) SiH/alkenyl group 1.1 1.1 1.0 0.8 0.7 1.1 0.9 Proportion of EO 1.00 1.00 1.00 0.58 0.64 1.00 EO content (mass %) 2.5 4.2 5.9 13.1 16.5 2.1 Viscosity (mPa .Math. s) 3720 2830 2290 3880 2720 6060 6830 Curability (minutes) 15 30 30 15 30 15 30 Transparency (%) >99 >99 >99 >99 >99 >99 >99 Refractive index 1.546 1.544 1.543 1.524 1.521 1.549 1.548 Cloudiness 0.5 0.0 0.0 0.0 0.0 10.0 6.0 Mode of adhesion Cohesive Cohesive Cohesive Cohesive Interfacial failure failure failure failure peeling

(23) It was confirmed from the results of Examples 1 to 5 that in the curable silicone composition of the present invention, the initial transparency of the cured product was high and tended not to cause clouding even after being exposed to high temperatures and high humidity. It was confirmed from the results of Comparative Example 1 that in the curable silicone composition free from component (B), the initial transparency of the cured product was high, but significantly caused clouding if exposed to high temperatures and high humidity.

Example 6

(24) 2.5 g of the curable silicone composition prepared in Example 2 was placed on a float glass having a thickness of 2 mm and lengths of the long side and short side of 165 mm and 105 mm, respectively, the gap was adjusted to 130 microns, a polycarbonate panel as a cover lens (thickness of 1 mm; lengths of the long side and short side of 210 mm and 160 mm; MRS-58T produced by Mitsubishi Gas Chemical, Inc.) was placed, and lamination under reduced pressure was carried out to obtain a laminate panel of glass-curable silicone composition-polycarbonate. The obtained laminate panel was placed in an oven set at 40 C. and heated for one hour to obtain a laminate panel containing a glass-silicone cured product-polycarbonate.

(25) The obtained laminate panel was aged for 24 hours at 90 C., with neither crack generation nor panel peeling observed.

(26) Similarly, the obtained laminate panel was subjected to durability testing in a thermal shock tester at 40 C./85 C. (retention time of 2 hours at 40 C. and 85 C.), with neither crack generation nor panel peeling observed after 40 cycles of the testing.

Examples 7 to 11 and Comparative Example 3

(27) The curable silicone compositions were prepared at the compositions (parts by mass) shown in Table 2 using the abovementioned components. Note that the liquid curable silicone composition was prepared in portions of liquids A and B for mixing at a mass ratio of 1:1. That is, the following components (b-1), (d-1), and (e-1) were blended in liquid A, the following components (c-1) and (c-2) were blended in liquid B, and liquids A and B were dispensed in components (a-1), (a-2), and (b-2). The thus prepared liquids A and B were mixed at a mass ratio of 1:1 using a static mixer to prepare a curable silicone composition. Note that in the table, the ratio of the SiH/alkenyl groups represents the value of the total number of moles of silicon atom bonded hydrogen atoms in components (c-1) to (c-2) to 1 mol of the total of vinyl groups in components (a-1) to (a-3) and methallyl groups in components (b-1) to (b-2) in the composition. Moreover, in the table, the proportion of EO represents the ratio of the number of moles of units represented by the formula: C.sub.2H.sub.4O with respect to the total number of moles of units represented by the formula: C.sub.2H.sub.4O and units represented by the formula: CH.sub.2CH(Me)O in components (b-1) to (b-2). Moreover, in the table, the EO content represents the proportion (mass %) of the total amount of units represented by formula: C.sub.2H.sub.4O in components (b-1) to (b-2) with respect to the total amount of components (a-1) to (a-3), (b-1) to (b-2), (c-1) to (c-2), and (d-1).

(28) TABLE-US-00002 TABLE 2 Comparative Present invention Example Example Example Comparative Example 7 Example 8 Example 9 10 11 Example 3 Curable silicone (a-1) 47.5 49.8 47.2 composition (a-2) 28.2 41.7 34.7 27.5 29.6 28.0 (parts by mass) (a-3) 35.2 29.3 46.4 (b-1) 5.0 5.0 5.0 (b-2) 5.0 1.0 (b-4) 5.0 (c-1) 7.1 7.8 6.9 8.9 7.1 7.8 (c-2) 0.5 1.0 1.0 0.8 0.4 0.4 (d-1) 0.2 0.3 0.3 0.3 0.2 0.2 (e-1) 1.0 6.6 20.5 8.6 9.4 8.9 (f-1) 2.0 2.0 2.0 2.0 2.0 2.0 (f-2) 0.5 0.5 0.5 0.5 0.5 0.5 SiH/alkenyl group 1.0 1.0 1.0 1.0 1.0 1.0 Proportion of EO 0.57 1.00 1.00 1.00 0.57 0 EO content (mass %) 2.4 4.1 4.1 4.1 0.5 0 Viscosity (mPa .Math. s) 1580 1780 1280 1010 1800 1340 Curability (minutes) 15 30 30 30 15 15 Transparency (%) >99 >99 >99 >99 >99 >99 Refractive index 1.541 1.543 1.542 1.543 1.545 1.541 Cloudiness 0.4 0.1 0.3 0.0 1.0 15.0 Mode of adhesion Cohesive Cohesive Cohesive Cohesive Cohesive Cohesive failure failure failure failure failure failure

(29) It was confirmed from the results of Examples 7 to 11 that in the curable silicone composition of the present invention, the viscosity was low, the initial transparency of the cured product was high, and it tended not to cause clouding even after being exposed to high temperatures and high humidity.

Example 12

(30) 2.5 g of the curable silicone composition prepared in Example 10 was placed on a float glass having a thickness of 2 mm and lengths of the long side and short side of 165 mm and 105 mm, respectively, the gap was adjusted to 130 microns, a polycarbonate panel as a cover lens (thickness of 1 mm; lengths of the long side and short side of 210 mm and 160 mm; MRS-58T produced by Mitsubishi Gas Chemical, Inc.) was placed, and lamination under reduced pressure was carried out to obtain a laminate panel of glass-curable silicone composition-polycarbonate. The obtained laminate panel was placed in an oven set at 40 C. and heated for one hour to obtain a laminate panel containing a glass-silicone cured product-polycarbonate.

(31) The obtained laminate panel was aged for 24 hours at 90 C., with neither crack generation nor panel peeling observed.

(32) Similarly, the obtained laminate panel was subjected to durability testing in a thermal shock tester at 40 C./85 C. (retention time of 2 hours at 40 C. and 85 C.), with neither crack generation nor panel peeling observed.

INDUSTRIAL APPLICABILITY

(33) Because the curable silicone composition of the present invention rapidly cures at relatively low temperatures and forms a cured product which maintains transparency and tends not to cause clouding and discoloration even if exposed to high temperatures and high humidity, the curable silicone composition is useful as an adhesive or pressure sensitive adhesive for optical displays.