Adhesive silicone composition and an adhesive film or tape

Abstract

An adhesive silicone composition having (A) a linear or branched organopolysiloxane having at least two alkenyl groups in a molecule (B) an organopolysiloxane comprising R.sup.2.sub.3SiO.sub.1/2 units and SiO.sub.4/2 units, wherein R.sup.2 is, independently of each other, a substituted or unsubstituted, monovalent hydrocarbon group having 1 to 10 carbon atoms, (C) an organohydrogenpolysiloxane having at least three hydrogen atoms each bonded to a silicon atom in a molecule and having no aryl group, and (E) an organohydrogenpolysiloxane having at least three hydrogen atoms each bonded to a silicon atom in a molecule and having an aryl group-containing organic group.

Claims

1. An adhesive silicone composition comprising the following components (A) through (E): (A) a linear or branched organopolysiloxane having at least two alkenyl groups in a molecule in an alkenyl group content of at least 0.0005 mol/100g and less than 0.15 mol/100g, in an amount of 40 to 100 parts by mass, (B) an organopolysiloxane comprising R.sup.2.sub.3 SiO.sub.1/2 units and SiO.sub.4/2 units, wherein R.sup.2 is, independently of each other, a substituted or unsubstituted, monovalent hydrocarbon group having 1 to 10 carbon atoms, having a mole ratio of the R.sup.2.sub.3 SiO.sub.1/2 units to the SiO.sub.4/2 units being 0.5 to 1.5, and optionally having a hydroxyl or alkoxy group bonded to a silicon atom, in an amount of 60 to 0 parts by mass, provided that a total amount of components (A) and (B) is 100 parts by mass, (C) an organohydrogenpolysiloxane having at least three hydrogen atoms each bonded to a silicon atom in a molecule and having no aryl group, in such an amount that a ratio of the number of the SiH groups in component (C) to the number of the alkenyl groups in component (A) is 0.5 to 15, (D) a platinum group metal catalyst in a catalytic amount, and (E) an organohydrogenpolysiloxane having at least three hydrogen atoms each bonded to a silicon atom in a molecule and having an aryl group-containing organic group, wherein a ratio of the number of the aryl group-containing organic group to a total of the number of the hydrogen atoms each bonded to a silicon atom and the number of groups each bonded to a silicon atom is 0.05 to 0.40, in an amount of 0.01 to 10 parts by mass per total 100 parts by mass of component (A) and component (B), provided that a ratio of the number of the SiH groups in component (E) to the number of the alkenyl groups in component (A) is 0.1 to 15.

2. The adhesive silicone composition according to claim 1, further comprising (F) an addition reaction control agent in an amount of 0.05 to 8 parts by mass per total 100 parts by mass of component (A) and component (B).

3. The adhesive silicone composition according to claim 1, wherein component (A) is represented by the following formula (1) ##STR00046## wherein R.sup.1 is, independently of each other, a hydroxyl group or a substituted or unsubstituted, monovalent hydrocarbon group having 1 to 10 carbon atoms, provided that at least two R.sup.1 are an alkenyl group-containing hydrocarbon group having 2 to 10 carbon atoms, a is an integer of 2 or more, b is an integer of 1 or more, c is an integer of 0 or more, d is an integer of 0 or more, and 100 a+b+c+d 20,000.

4. The adhesive silicone composition according to claim 1, wherein component (C) is represented by the following average compositional formula (2):
R.sup.3.sub.eH.sub.fSiO.sub.(4-e-f)/2  (2) wherein R.sup.3 is, independently of each other, a hydroxyl group or a substituted or unsubstituted, monovalent hydrocarbon group having no aliphatic unsaturated bond, provided that R.sup.3 is not an aryl group-containing organic group, e and f are a positive number, and e+f≤3.

5. The adhesive silicone composition according to claim 3, wherein component (A) is represented by the following formula (3) or (4) ##STR00047## wherein R.sup.4 is, independently of each other, a substituted or unsubstituted, monovalent hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bond, X is an alkenyl group-containing hydrocarbon group having 2 to 10 carbon atoms, g is an integer of 0 to 3, h is an integer of 0 or more, h′ is an integer of 2 or more, i is an integer of 100 or more, 2g+h ≥2, 102 h+i+2≤20,000, and 104 ≤h′+i+2≤20,000.

6. The adhesive silicone composition according to claim 1, wherein component (E)has an average degree of polymerization of 500 or less.

7. The adhesive silicone composition according to claim 6, wherein component (E) is represented by the following formula (5) ##STR00048## wherein R.sup.5 is, independently of each other, a substituted or unsubstituted, monovalent hydrocarbon group having 1 to 10 carbon atoms and having no aliphatic unsaturated bond, provided that at least one R.sup.5 is an aryl group-containing organic group having 6 to 10 carbon atoms, j is 0 or 1, k and m are an integer satisfying the following equations: 1≤k≤400, 0 ≤400, 3≤2j+k≤400, and 3 ≤k+m≤498.

8. The adhesive silicone composition according to claim 1, wherein in component (E), a ratio of the number of the aryl group-containing organic groups each bonded to a silicon atom to a total of the number of the hydrogen atoms each bonded to a silicon atom and the number of the groups each bonded to a silicon atom is 0.08 to 0.30.

9. The adhesive silicone composition according to claim 1, further comprising (G) an organo(poly)siloxane or other organic compound having at least two alkenyl groups in a molecule with an alkenyl group content of 0.15 to 2.5 mol/100g, in an amount of 0.01 to 10 parts by mass per total 100 parts by mass of component (A) and component (B).

10. The adhesive silicone composition according to claim 1, further comprising (H) an α-silyl aliphatic ester represented by the following formula (6) in an amount of 0.01 to 5 parts by mass per total 100 parts by mass of component (A) and component (B) ##STR00049## wherein R.sup.6 is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R.sup.7 is a hydrogen atom or a methyl group, R.sup.8 is, independently of each other, an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms, R.sup.9 is, independently of each other, an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms, and n is an integer of 1 to 3.

11. A cured product obtained by curing the adhesive silicone composition according to claim 1.

12. An adhesive film or tape comprising a base material and an adhesive layer provided on at least one surface of the base material, wherein the adhesive layer is the cured product according to claim 11.

13. The adhesive film or tape according to claim 12, wherein the base material is a plastic film.

Description

EXAMPLES

(1) The present invention will be explained below in further detail with reference to a series of the Examples and the Comparative Examples. However, the present invention is in no way limited by these Examples.

(2) In the following, the viscosity is such at 25 degrees C., “part” is in mass, and the characteristics were determined according to the following test methods. Me means a methyl group and Vi means a vinyl group.

Adhesive Silicone Base Composition I

Preparation Example 1

(3) Component (A) was dimethylpolysiloxane (90.0 parts by mass) of which both ends of the molecular chain were blocked by a vinyl group, and which had an alkenyl group content of 0.002 mol/100 g and was represented by the following formula.

(4) ##STR00034##
Component (B) was a 60% by mass solution in toluene (16.67 parts by mass) of a polysiloxane consisting of Me.sub.3SiO.sub.0.5 units and SiO.sub.2 units in a mole ratio of Me.sub.3SiO.sub.0.5 units/SiO.sub.2 units of 0.85, and having hydroxyl groups each bonded to a silicon atom of the SiO.sub.2 units in a hydroxyl group content of 1.2% by mass, and having a weight-average molecular weight of 4,000.
Component (C) was a polyorganohydrogensiloxane (0.29 part by mass) represented by the following formula (C-1):

(5) ##STR00035##
and a polyorganohydrogensiloxane (0.41 part by mass) represented by the following formula (C-2):

(6) ##STR00036##
Component (F) was ethynylcyclohexanol (0.20 part by mass). Components (A), (B), (C) and (F) were mixed together, to which toluene was then added to obtain an adhesive silicone base composition I having a content of the effective components of about 60% by mass.

Adhesive Silicone Base Composition II without Component (B)

Preparation Example 2

(7) Component (A) was a dimethylpolysiloxane (30.0 parts by mass) of which both ends of the molecular chain were blocked by a vinyl group and which had an alkenyl group content of 0.002 mol/100 g and was represented by the following formula:

(8) ##STR00037##
This component (A), the aforesaid component (C-1) (0.38 part by mass), and component (F) (0.20 part by mass) were mixed together, to which toluene was then added to obtain an adhesive silicone base composition II having a content of the effective components of about 30% by mass.

Solvent-Free Adhesive Silicone Base Composition III

Preparation Example 3

(9) Component (A) was a dimethylpolysiloxane (100.0 parts by mass) of which both ends of the molecular chain blocked were by a vinyl group and which had an alkenyl group content of 0.004 mol/100 g and was represented by the following formula:

(10) ##STR00038##
This component (A), the aforesaid component (C-1) (0.45 part by mass), and component (F) (0.10 part by mass) were mixed together to obtain an adhesive silicone base composition III.
Components (D) to (G) and comparative component (E2-1) used in the preparation of the adhesive silicone compositions were as follows.
Component (D)

(11) (D-1) a solution of a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum (0) complex in toluene, containing 0.5% by mass of platinum

(12) (D-2) a solution of a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum (0) complex in silicone containing 0.5% by mass of platinum

(13) Component (E)

(14) (E-1) methyl hydrogenpolysiloxane, represented by the following formula and having a ratio of the number of the aryl group-containing organic group of 0.096.

(15) ##STR00039##

(16) (E-2) methyl hydrogenpolysiloxane represented by the following formula and having a ratio of the number of the aryl group-containing organic group of 0.197.

(17) ##STR00040##

(18) (E-3) methyl hydrogenpolysiloxane represented by the following formula and having a ratio of the number of the aryl group-containing organic group of 0.199

(19) ##STR00041##

(20) (E2-1) methyl hydrogenpolysiloxane represented by the following formula and having a ratio of the number of the aryl group-containing organic group of 0.000 (for comparison)

(21) ##STR00042##
Component (G)

(22) (G-1) organopolysiloxane represented by the following average compositional formula and having a viscosity at 25 degrees C. of 0.03 Pa.Math.s and an alkenyl group content of 0.53 mol/100 g

(23) ##STR00043##

(24) (G-2) organopolysiloxane represented by the following formula and having an alkenyl group content of 0.22 mol/100 g

(25) ##STR00044##
Component (H): ethyl α-trimethoxysilylpropionate

(I) Manufacture of Additives for the Comparative Examples

(26) Adherence improver (I-1), as described in Patent Literature 6 (WO2015/194389) and Patent Literature 7 (JP Application Laid-Open 2015-178584

(27) In a one-liter separable flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser tube, were placed 288.6 g (1.2 mol) of 1,3,5,7-tetramethylcyclotetrasiloxane, 300.0 g of toluene, and 0.06 g of a toluene solution (platinum content, 0.5% by mass) of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum (0) complex, and mixed, and heated to about 70 degrees C. To this, was then added dropwise 123.4 g (0.4 mol) of 2,2-bis(4-allyloxyphenyl)propane from the dropping funnel, and heated to about 80 to 85 degrees C. after completion of the dropping, and allowed to react at this temperature for 1 hour. Then, 0.6 g of activated carbon was added to remove the catalyst platinum, mixed for 2 hours, and then the activated carbon was removed by filtration. The resulting liquid was subjected to a vacuum concentration at 90 degrees C. for 8 hours to obtain a colorless transparent liquid. Analysis showed that the liquid was a mixture of the compounds represented by the following formula, wherein r is of from 0 to 4, and the compound with r=2 was a major component.

(28) ##STR00045##

(29) Adherence improver (I-2) as described in Patent Literature 5 (JP Application Laid-Open 2015-074741))

(30) In a 500-mL separable flask equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser tube, were placed 33.2 g (0.14 mol, 9.5 mol %) of 3-glycidoxypropyltrimethoxysilane, 63.6 g (0.48 mol, 32.5 mol %) of methylvinyldimethoxysilane, 103.2 g (0.86 mol, 58.0 mol %) of dimethyldimethoxysilane, and 16.0 g of methanol, to which a solution consisting of 39.2 g of water, 50.6 g of methanol, and 1.4 g of 28% ammonia water was added dropwise at room temperature, and mixed at room temperature for 16 hours. Thereafter, the mixture was concentrated under reduced pressure at 60 degrees C. for 4 hours and subjected to filtration to obtain a colorless, transparent and oily adherence improver having a weight average molecular weight of 1,200.

Examples 1˜7 and Comparative Examples 1-6

(31) The adhesive silicone base composition I, component (E) or comparative component (E2-1), component (G), component (H), and component (I) were placed in a flask in the amounts shown in Tables 1 and 2, to which 50 parts by mass of toluene was added and stirred to dissolve them. To the resulting solution, 0.5 part by mass of component (D-1) was added and stirred to obtain an adhesive silicone composition. An adhesive tape was prepared using this adhesive silicone composition and its adhesion strength and adherence were determined with time in the manner described below. The results are as seen in Tables 1 and 2.

Examples 8 and 9 and Comparative Example 7

(32) The adhesive silicone base composition II, component (E), and component (G) were placed in a flask in the amounts shown in Table 3 and stirred to dissolve them. To the resulting solution, 0.2 part by mass of component (D-1) was added and mixed to prepare an adhesive silicone composition. An adhesive tape was prepared using this adhesive silicone composition and its adhesion strength and adherence were determined with time in the manner described below. The results are as seen in Table 3.

Examples 10 and 11 and Comparative Examples 8 to 10

(33) The adhesive silicone base composition III, component (E), component (G), component (H), and component (I) were placed in a flask in the amounts shown in Table 3 and stirred to dissolve them. To the resulting solution, 0.5 part by mass of component (D-2) was added and mixed to prepare an adhesive silicone composition. An adhesive tape was prepared using this adhesive silicone composition and its adhesion strength and adherence were determined with time in the manner described below. The results are as seen in Table 3.

(34) Adhesion Strength Test

(35) Each of the adhesive silicone compositions obtained was applied, using an applicator, on a polyethylene terephthalate (PET) film having a thickness of 23 μm and a width of 25 mm so as to have a coating thickness of 30 μm after cured, and then heated to cure at 130 degrees C. for one minute to prepare an adhesive tape. The adhesive tape was adhered on a glass plate, and pressed by two cycles of motion of a 2 kg-weight roller covered with a rubber layer. The glass plate to which the adhesive tape was adhered was left at room temperature (25 degrees C., 50% RH) or at 60 degrees C., 90% RH for predetermined days, and then taken out. A force (in N/25 mm) required to peel the tape off from the glass plate at 1800 in a rate of 0.3 m per minute was determined with a tensile tester.

(36) Adherence Test

(37) An adhesive tape was prepared as described above. After the adhesive tape was left at room temperature (25 degrees C., 50% RH) or at 60 degrees C., 90% RH, a part of the cured adhesive layer was scratched with a projection such as a nail or a cutter, and this part was rubbed with a finger abdomen to see if the cured adhesive layer was peeled off from the base material to evaluate adherence. The results are rated as follows.

(38) G: The cured adhesive layer is not peeled off from the base material.

(39) M: The cured adhesive layer is partially peeled off from the base material.

(40) B: The cured adhesive layer is entirely peeled off from the base material.

(41) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 Adhesive silicone base I, part by mass 100 100 100 100 100 100 100 Component (E), (E-1) 0.2 0.2 0.4 0.2 part by mass (E-2) 0.2 0.2 (E-3) 0.2 (E2-1) for comparison Component (G), (G-1) 0.2 0.4 0.2 part by mass (G-2) 0.2 Component (H), (H) 0.2 part by mass Additive (I) for (I-1) comparison, (I-2) part by mass Ratio of the numbers, H/Vi 5.0 5.0 5.0 5.0 5.0 5.0 5.0 [(C)]/[(A)] Ratio of the numbers, H/Vi 2.2 1.6 1.7 2.2 4.5 2.2 1.6 [(E)]/[(A)] Adhesion room temp., 0.04 0.05 0.05 0.04 0.06 0.04 0.05 strength, after one day N/25 mm room temp., 0.06 0.04 0.04 0.05 0.06 0.05 0.05 after seven days 60 degrees C., 90% RH, 0.08 0.10 0.10 0.07 0.08 0.07 0.05 after one day 60 degrees C., 90% RH, 0.16 0.17 0.15 0.12 0.12 0.13 0.11 after seven days Adherence room temp., G G G G G G G after one day room temp., G G G G G G G after seven days 60 degrees C., 90% RH, G G G G G G G after one day 60 degrees C., 90% RH, G G G G G G G after seven days

(42) TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 4 5 6 Adhesive silicone base I, part by mass 100 100 100 100 100 100 Component (E), (E-1) part by mass (E-2) (E-3) (E2-1) for comparison 0.2 Component (G,) (G-1) 0.2 0.2 part by mass (G-2) Component (H), (H) part by mass Additive (I) for (I-1) 0.2 0.2 comparison, (I-2) 0.5 part by mass Ratio of the numbers, H/Vi 5.0 5.0 5.0 5.0 5.0 5.0 [(C)]/[(A)] Ratio of the numbers, H/Vi — 2.9 — — — — [(E)]/[(A)] Adhesion strength, room temp., 0.04 0.04 0.05 0.08 0.06 0.05 N/25 mm after one day room temp., 0.06 0.04 0.06 0.09 0.08 0.05 after seven days 60 degrees C., 90% RH, 0.09 0.07 0.18 0.16 0.14 0.06 after one day 60 degrees C., 90% RH, 0.13 *1 *1 *1 *1 0.23 after seven days Adherence room temp., G G G G G G after one day room temp., M M M G G B after seven days 60 degrees C., 90% RH, B B B G G B after one day 60 degrees C., 90% RH, B B B G G G after seven days ※1: The adhesive layer remained on the glass plate.

(43) As seen in Table 2, the composition of Comparative Example 1 containing no adherence improver and the composition of Comparative Example 2 containing component (E2) having no aryl group, and the composition of Comparative Example 3 containing component (G) without component (E) failed to have good adherence over time. The compositions of Comparative Examples 4 and 5 containing the comparative adherence improver (I-1) showed the good adherence, but their adhesion strengths increased with time so that after 7 days at 60 degrees C., 90% RH, the adhesive layer remained on the glass surface. The composition of Comparative Example 6 containing the comparative adherence improver (I-2) showed the good initial adherence and the good adherence after 7 days at 60 degrees C., 90% RH, but the adherence after 7 days at room temperature and after one day at 60 degrees C., 90% RH was bad.

(44) On the other hand, as seen in Table 1, the adhesive silicone compositions of the present invention (Examples 1 to 7) containing component (E) which was an adherence-improving agent exhibited good adherence at room temperature and at 60 degrees C., 90% RH, even applied in one coating step. Increase in adhesion strength with time was suppressed.

(45) TABLE-US-00003 TABLE 3 Example Comparative Example 8 9 10 11 7 8 9 10 Adhesive silicone base II, 100 100 100 part by mass Adhesive silicone base III, 100 100 100 100 100 part by mass Component (E), (E-1) 0.2 0.2 0.8 0.8 part by mass Component (G), (G-1) 0.2 0.8 0.8 0.8 part by mass Component (H), (H) 0.4 part by mass Additive (I) for (I-1) 0.8 0.8 comparison, part by mass Ratio of the numbers, H/Vi 10.0 10.0 2.0 2.0 10.0 2.0 2.0 2.0 [(C)]/[(A)] Ratio of the numbers, H/Vi 4.0 4.0 2.7 2.7 — — — — [(E)]/[(A)] Adhesion room temp., 0.07 0.06 0.03 0.04 0.10 0.05 1.19 0.03 strength, after one day N/25 mm room temp., 0.09 0.06 0.05 0.05 0.09 0.12 *2 0.09 after seven days 60 degrees C., 0.14 0.11 0.16 0.15 0.17 0.14 *2 0.10 90% RH, after one day 60 degrees C., 0.25 0.23 0.31 0.29 0.29 *1 *1 0.76 90% RH, after seven days Adherence room temp., G G G G G G G G after one day room temp., G G G G G M G G after seven days 60 degrees C., G G G G M B G M 90% RH, after one day 60 degrees C., G G G G B B M B 90% RH, after seven days ※1: The adhesive layer remained on the glass plate. ※2: The adhesive layer caused cohesive failure.

(46) As seen in Table 3, even the adhesive silicone compositions (Examples 8 and 9) and the solvent-free adhesive silicone compositions (Examples 10 and 11), all of which did not contain component (B), showed the good adherence on account of component (E), and the suppressed increase in the adhesion strength with time. On the other hand, the adhesive silicone compositions of Comparative Examples 7 and 8 which did not contain the adherence-improving component (E) failed to have good adherence at 60 degrees C., 90%. In Comparative Examples 9 and 10 where the comparative adherence improver (I-1), the adherence was improved, but the adhesion strength increased with time.

INDUSTRIAL APPLICABILITY

(47) The cured product formed by curing the adhesive silicone composition of the present invention has the excellent adherence to a base material and the suppressed increase in adhesion strength with time. This makes it possible to provide an adhesive film or tape having excellent stability.