Organopolysiloxane composition and method for producing same, and silicone composition for mist suppressor as well as solvent-free release paper or release film

Abstract

An organopolysiloxane composition obtained by dissolving in a solvent an organopolysiloxane crosslinked product obtained by repeating one or more times a process of again introducing an organopolysiloxane and an organohydrogenpolysiloxane to a product, obtained by conducting an addition reaction of an organopolysiloxane of a specific structure and an organohydrogenpolysiloxane of a specific structure using a platinum group metal-based compound in 10-50 times the total mass of these polysiloxanes, and conducting an addition reaction using a platinum group metal-based compound.

Claims

1. A method for preparing an organopolysiloxane composition comprising the steps of: effecting addition reaction of an organopolysiloxane of structure having the formula (1) and an organohydrogenpolysiloxane of structure having the formula (2) in a solvent in the presence of a platinum group metal base compound, the amount of the solvent being 10 to 50 times the total weight of the polysiloxanes of formulae (1) and (2), to form a product, adding the organopolysiloxane of structure having the formula (1) and the organohydrogenpolysiloxane of structure having the formula (2) again to the product, effecting addition reaction in the presence of the platinum group metal base compound, repeating at least one time the addition and reaction steps, thereby yielding an organopolysiloxane crosslinked product,
M.sub.αM.sup.Vi.sub.βD.sub.γD.sup.Vi.sub.δT.sub.εT.sup.Vi.sub.ζQ.sub.η  (1)
M.sub.θM.sup.H.sub.lD.sub.κD.sup.H.sub.λT.sub.μT.sup.H.sub.νQ.sub.η  (1) wherein M is R.sub.3SiO.sub.1/2, M.sup.Vi is R.sub.2PsiO.sub.1/2, D is R.sub.2SiO.sub.2/2, D.sup.Vi is RPSiO.sub.2/2, T is RSiO.sub.3/2, T.sup.Vi is PSiO.sub.3/2, M.sup.H is R.sub.2HSiO.sub.1/2, D.sup.H is RHSiO.sub.2/2, T.sup.H is HSiO.sub.3/2, Q is SiO.sub.4/2, R is each independently a substituted or unsubstituted C.sub.1-C.sub.12 monovalent hydrocarbon group free of aliphatic unsaturation, P is an alkenyl group: —(CH.sub.2).sub.a—CH═CH.sub.2 wherein a is 0 or an integer of 1 to 6, α, β, γ, δ, ε, ζ, η, θ, l, κ, λ, μ, and ν are each independently 0 or a positive number, β, δ and ζ are not equal to 0 at the same time, β+δ+ζ≥2, l, λ, and ν are not equal to 0 at the same time, l+λ+ν≥2, β+δ+ζ and l+λ+ν are not equal to 2 at the same time.

2. The method of claim 1 wherein the addition reaction of first stage has a conversion rate of at least 90%.

3. The method of claim 1 wherein a solvent having a boiling point of 50° C. to 200° C. is used as the solvent in the amount of 10 to 50 times the total weight of the polysiloxanes of formulae (1) and (2), addition reaction is effected plural divided times, and after the organopolysiloxane crosslinked product is obtained, vinylmethylpolysiloxane is added thereto and the solvent is then removed.

4. The method of claim 2 wherein a solvent having a boiling point of 50° C. to 200° C. is used as the solvent in the amount of 10 to 50 times the total weight of the polysiloxanes of formulae (1) and (2), addition reaction is effected plural divided times, and after the organopolysiloxane crosslinked product is obtained, vinylmethylpolysiloxane is added thereto and the solvent is then removed.

Description

EXAMPLE

(1) Synthesis Examples, Examples, and Comparative Examples are given below by way of illustration and not by way of limitation. The viscosity reported below is as measured at 25° C. by an Ostwald viscometer.

(2) In the Examples below, symbols indicative of the composition of siloxanes designate the following units.
M=(CH.sub.3).sub.3SiO.sub.1/2
M.sup.Vi=(CH.sub.2═CH)(CH.sub.3).sub.2SiO.sub.1/2
D=(CH.sub.3).sub.2SiO.sub.2/2
D.sup.H=(CH.sub.3)HSiO.sub.2/2
T=(CH.sub.3)SiO.sub.3/2

[Synthesis Example 1] Synthesis of Mist Suppressant Used in Examples 1 and 2

(3) Linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2, 10 g, and 48 g (SiH groups:vinyl groups=1 mol:1.097 mol) of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4D.sub.147.7T.sub.0.4 were mixed in 911 g (corresponding to 15.7 times the total weight of linear methylhydrogenpolysiloxane and branched vinylmethylpolysiloxane) of dimethylpolysiloxane having a viscosity at 25° C. of 20 mm.sup.2/s. A platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The system was heated whereupon reaction was run at a temperature of 80° C. for 5 hours. The reaction product thus obtained was present in the solution in a concentration of 5% by weight and was an oil having a viscosity of 42 mm.sup.2/s, a hydrogen gas evolution of 0.12 ml/100 g and a conversion rate of 99.5%.

(4) To the composition of the reaction product in dimethylpolysiloxane, 10 g of linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2 and 48 g of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4 D.sub.147.7T.sub.0.4 were added again. With stirring, a platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The reaction was run at a temperature of 80° C. for 5 hours. The organopolysiloxane crosslinked product thus obtained was present in the solution in a concentration of 11.29% by weight and was an oil having a viscosity of 135 mm.sup.2/s, a hydrogen gas evolution of 0.08 ml/100 g and a conversion rate of 99.8%. It had 13.3 mol of silethylene bond per 1,000 mol of siloxane units as computed from .sup.1H-NMR analysis.

(5) To 10 g of the composition of the organopolysiloxane crosslinked product in dimethylpolysiloxane, 90 g of toluene was added and mixed. The solution contained the organopolysiloxane crosslinked product in a concentration of 1.1% by weight, and could be filtered through a cellulose acetate cartridge filter DISMIC-13CP (Advantec Group). The organopolysiloxane crosslinked product as filtered had a weight average molecular weight of 3.5×10.sup.6. The Mw was determined by GPC-MALS under the following conditions: GPC HLC-8120 (Tosoh Corp.), column TSKgel GMHHR-H(30)×2 (Tosoh Corp.), eluent toluene, detector MALS DAWN HELEOS (Wyatt Technology).

[Synthesis Example 2] Synthesis of Mist Suppressant Used in Example 3

(6) Linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2, 10 g, and 48 g (SiH groups:vinyl groups=1 mol:1.097 mol) of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4 D.sub.147.7T.sub.0.4 were mixed in 911 g (corresponding to 15.7 times the total weight of linear methylhydrogenpolysiloxane and branched vinylmethylpolysiloxane) of toluene. A platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The system was heated whereupon reaction was run at a temperature of 80° C. for 5 hours. The reaction product thus obtained was present in the solution in a concentration of 11% by weight and had a viscosity of 1.7 mm.sup.2/s, a hydrogen gas evolution of 0.12 ml/100 g and a conversion rate of 99.5%.

(7) To the composition of the reaction product in toluene, 10 g of linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2 and 48 g of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4 D.sub.147.7T.sub.0.4 were added again. With stirring, a platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The reaction was run at a temperature of 80° C. for 5 hours. The solution of the organopolysiloxane crosslinked product thus obtained had a viscosity of 5.4 mm.sup.2/s, and the organopolysiloxane crosslinked product had a hydrogen gas evolution of 0.07 ml/100 g and a conversion rate of 99.8%. It had 13 mol of silethylene bond per 1,000 mol of siloxane units as computed from .sup.1H-NMR analysis.

(8) To 10 g of the composition of the organopolysiloxane crosslinked product in toluene, 90 g of toluene was added and mixed. The solution contained the organopolysiloxane crosslinked product in a concentration of 1.1% by weight, and could be filtered through a cellulose acetate cartridge filter DISMIC-13CP (Advantec Group). The organopolysiloxane crosslinked product as filtered had a Mw of 3.3×10.sup.6.

(9) To the composition of the organopolysiloxane crosslinked product in toluene, 58 g of dimethylpolysiloxane having vinyl groups at both ends, represented by M.sup.Vi.sub.2D.sub.66.8 was added. Under nitrogen bubbling, this was distilled at 150° C. for 2 hours and under a vacuum of 10 mmHg or below, obtaining a 100% siloxane composition. The composition had a viscosity of 2,495 mm.sup.2/s.

[Synthesis Example 3] Synthesis of Mist Suppressant Used in Example 4

(10) Side chain methylhydrogenpolysiloxane represented by M.sub.2D.sub.24D.sup.H.sub.4, 10 g, and 109.3 g (SiH groups:vinyl groups=1 mol:1.097 mol) of dual terminated vinylmethylpolysiloxane represented by M.sup.Vi.sub.2D.sub.144 were mixed in 2,386 g (corresponding to 20 times the total weight of side chain methylhydrogenpolysiloxane and dual terminated vinylmethylpolysiloxane) of dimethylpolysiloxane having a viscosity at 25° C. of 20 mm.sup.2/s. A platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The system was heated whereupon reaction was run at a temperature of 80° C. for 5 hours. The reaction product thus obtained was present in the solution in a concentration of 4.76% by weight and was an oil having a viscosity of 780 mm.sup.2/s, a hydrogen gas evolution of 0.0 ml/100 g and a conversion rate of 100%.

(11) To the composition of the reaction product in dimethylpolysiloxane, 10 g of side chain methylhydrogenpolysiloxane represented by M.sub.2D.sub.24D.sup.H.sub.4 and 109.3 g of dual terminated vinylmethylpolysiloxane represented by M.sup.Vi.sub.2D.sub.144 were added again. With stirring, a platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The system was heated whereupon reaction was run at a temperature of 80° C. for 5 hours. The organopolysiloxane crosslinked product thus obtained was present in the solution in a concentration of 9% by weight and was an oil having a viscosity of 2,507 mm.sup.2/s, a hydrogen gas evolution of 0.006 ml/100 g and a conversion rate of 98.0%. It had 15.2 mol of silethylene bond per 1,000 mol of siloxane units as computed from .sup.1H-NMR analysis.

(12) To 10 g of the composition of the organopolysiloxane crosslinked product in dimethylpolysiloxane, 90 g of toluene was added and mixed. The solution contained the organopolysiloxane crosslinked product in a concentration of 0.9% by weight, and could be filtered through a cellulose acetate cartridge filter DISMIC-13CP (Advantec Group). The organopolysiloxane crosslinked product as filtered had a Mw of 3.3×10.sup.6.

[Synthesis Example 4] Synthesis of Mist Suppressant Used in Comparative Example 1

(13) Linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2, 20 g, and 96 g (SiH groups:vinyl groups=1 mol:1.097 mol) of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4 D.sub.147.77T.sub.0.4 were mixed in 1,044 g (corresponding to 9 times the total weight of linear methylhydrogenpolysiloxane and branched vinylmethylpolysiloxane) of toluene. A platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. On heating, the system gelled when the temperature reached about 70° C.

[Synthesis Example 5] Synthesis of Mist Suppressant Used in Comparative Example 2

(14) Linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2, 20 g, and 96 g (SiH groups:vinyl groups=1 mol:1.097 mol) of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4 D.sub.147.7T.sub.0.4 were mixed in 1,044 g (corresponding to 9 times the total weight of linear methylhydrogenpolysiloxane and branched vinylmethylpolysiloxane) of dimethylpolysiloxane represented by M.sub.2D.sub.27. A platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. On heating, the system gelled when the temperature reached about 70° C.

[Synthesis Example 6] Synthesis of Mist Suppressant Used in Comparative Example 3

(15) Linear methylhydrogenpolysiloxane represented by M.sub.2D.sub.24.6D.sup.H.sub.2, 10 g, and 48 g (SiH groups:vinyl groups=1 mol:1.097 mol) of branched vinylmethylpolysiloxane represented by M.sup.Vi.sub.2.4 D.sub.147.7T.sub.0.4 were mixed in 911 g (corresponding to 15.7 times the total weight of linear methylhydrogenpolysiloxane and branched vinylmethylpolysiloxane) of dimethylpolysiloxane having a viscosity at 25° C. of 20 mm.sup.2/s. A platinum catalyst having vinylmethylpolysiloxane coordinated was added in an amount to give 2 ppm of platinum based on the total weight of the reaction system. The system was heated whereupon reaction was run at a temperature of 80° C. for 5 hours. The reaction product thus obtained was present in the solution in a concentration of 5% by weight and was an oil having a viscosity of 42 mm.sup.2/s, a hydrogen gas evolution of 0.12 ml/100 g and a conversion rate of 99.5%. It had 7.4 mol of silethylene bond per 1,000 mol of siloxane units as computed from .sup.1H-NMR analysis.

Examples 1 to 4 and Comparative Examples 1 to 4

(16) A silicone composition was prepared according to the procedure shown below by blending each of the mist suppressants prepared in the above Synthesis Examples in the basic composition described below, and cured.

(17) Notably, the viscosity of the silicone composition was measured by the aforementioned method. The amount of mist generated from the silicone composition, the release force of a cured coating of the silicone composition and residual adhesion were measured by the following test methods. All the silicone compositions cured without any problems.

(18) <Preparation of Silicone Composition>

(19) Silicone compositions were prepared by combining 100 parts by weight of dimethylpolysiloxane having vinyldimethylsiloxy groups at both ends, represented by the formula (7):

(20) ##STR00004##
2.7 parts by weight of methylhydrogenpolysiloxane represented by the formula (8):

(21) ##STR00005##
0.4 part by weight of ethynyl cyclohexanol, and 2 parts by weight (100 ppm on platinum weight basis) of a complex salt of chloroplatinic acid with vinylsiloxane to form a base compound, blending 1 or 2 parts by weight of the mist suppressants prepared in the above Synthesis Examples in the base compound, and thoroughly mixing the ingredients. The formulation is shown in Tables 1 and 2.
<Method of Measuring Misting Amount>

(22) The misting amount was measured by coating 1.6 g of the silicone composition on the roller at the top of Misting Tester (Toyo Seiki Ltd.), rotating three rollers at 1,400 rpm, and measuring the amount of generated mist by Dusttrak Aerosol Monitor Model 8520 (TSI Inc.). One opening of a vinyl tube having an inner diameter of 7 mm was placed 15 cm straight above the top roller while the other opening was coupled to the suction site of Dusttrak Aerosol Monitor. While mist measurement was continued for 180 seconds, the maximum was recorded. The maximum detection limit of Dusttrak Aerosol Monitor is 150 mg/m.sup.3. The results are shown in Tables 1 and 2.

(23) <Method of Curing Silicone Composition>

(24) The silicone composition prepared above was coated onto a polyethylene-laminated paper substrate in a coating weight of 0.9 to 1.1 g/m.sup.2 by RI coater (IHI Machine System), to and heated in a hot air dryer at 140° C. for 30 seconds. The coated substrate designated as silicone separator was used in the following measurements.

(25) <Surface State of Coated Sample>

(26) The silicone separator obtained by the above method was visually observed on its surface and rated “0” for satisfactory coating, “Δ” for coating with an acceptable level of slight asperities or foreign particles, and “X” for coating with asperities or foreign particles. The results are shown in Tables 1 and 2.

(27) <Method of Measuring Release Force>

(28) A sample was prepared by holding the silicone separator obtained by the above method at 25° C. for 20 hours, then attaching TESA-7475 tape thereto, and holding the assembly under a load of 20 g/m.sup.2 in a dryer at 70° C. for 20 hours. Using a tensile tester, the TESA-7475 tape was peed from the sample at an angle of 180° and a rate of 0.3 m/min. The force required for peeling is reported as release force (gf/25 mm). The results are shown in Tables 1 and 2.

(29) <Method of Measuring Residual Adhesion>

(30) The TESA-7475 tape after the peel test was rested on a stainless steel plate and press bonded thereto by moving a tape roller of 2 kg over one back-and-forth stroke. Using a tensile tester, the TESA-7475 tape was peeled from the plate at an angle of 180° and a rate of 0.3 m/min. The (re-release) force required for peeling again was measured, from which a residual adhesion was computed according to the following formula. The results are shown in Tables 1 and 2.
Residual adhesion (%)=(re-release force)/(release force)×100

(31) TABLE-US-00001 TABLE 1 Silicone composition, Example amount (pbw) 1 2 3 4 Mist suppressant Synthesis Example 1 1 2 — — Synthesis Example 2 — — 2 — Synthesis Example 3 — — — 2 Divinyldimethylpolysiloxane 100 100 100 100 Methylhydrogenpolysiloxane 2.7 2.7 2.7 2.7 Ethynyl cyclohexanol 0.4 0.4 0.4 0.4 Complex salt of chloroplatinic acid/vinyl 2 2 2 2 siloxane Evaluation results Silicone composition viscosity (mm.sup.2/s) 370 362 392 381 Misting (max over 180 sec, mg/m.sup.3) 27 12 14 10 Surface state of coated sample ◯ ◯ ◯ ◯ Release force (gf/25 mm) 12 11 11 11 Residual adhesion (%) 97 96 97 96

(32) TABLE-US-00002 TABLE 2 Silicone composition, Comparative Example amount (pbw) 1 2 3 4 Mist suppressant Synthesis Example 4 2 — — — Synthesis Example 5 — 2 — — Synthesis Example 6 — — 2 — Divinyldimethylpolysiloxane 100 100 100 100 Methylhydrogenpolysiloxane 2.7 2.7 2.7 2.7 Ethynyl cyclohexanol 0.4 0.4 0.4 0.4 Complex salt of chloroplatinic acid/vinyl 2 2 2 2 siloxane Evaluation results Silicone composition viscosity (mm.sup.2/s) 375 378 361 377 Misting (max over 180 sec, mg/m.sup.3) 135 110 52 150 Surface state of coated sample X X Δ-◯ X Release force (gf/25 mm) 14 14 12 15 Residual adhesion (%) 97 96 97 96