JPH11148012A - Silicone emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject emulsion suppressed in foaming property and improved in mechanical stability without lowering surface tension by including a specific diorganopolysiloxane, a specific emulsifier, a polyhydric alcohol and water. SOLUTION: This emulsion is obtained by including (A) 10-60 wt.% diorganopolysiloxane having 100-1,000,000 cps viscosity (at 25 deg.C) and represented by the formula [R<1> is a 1-20C (un)saturated monofunctional hydrocarbon; R<2> is a 1-20C (un)saturated monofunctional hydrocarbon, a hydroxyl group of the formula OR<3> (R<3> is H or a 1-6C alkyl) or an alkoxy; (m) is 50-2,500], (B) 0.1-10 wt.% anionic emulsifier (e.g. sodium dodecylbenzenesulfonate), (C) 1-20 wt.% polyhydric alcohol (e.g. glycerol) and (D) the balance of water. The emulsion has >=45 dyne/cm surface tension (at 25 deg.C) obtained when diluted to 50 times by deionized water and the components A, B and D preferably form an anionic emulsified polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicone emulsion suitable as a mold release agent for molding synthetic resins, natural rubbers, synthetic rubbers and the like and a coating agent for synthetic resin films, sheets or paper surfaces.

[0002]

2. Description of the Related Art An emulsion of diorganopolysiloxane is applied to the surface of a mold when molding synthetic resin, natural rubber, synthetic rubber, or the like, or is applied to the surface of a synthetic resin film, sheet, or paper to obtain a release property. And is widely used to provide slipperiness. (See Japanese Patent Publication No. 52-40918 and No. 2507248)

[0003]

When these emulsions are industrially used as a mold release agent, they are diluted with water and applied by spraying, rolling, dipping or the like. Is often recovered and circulated for use with pumps and the like. At this time, if the surface tension of the emulsion is too low, a large amount of foam is generated, the applied amount becomes unstable, and the uniformity of the coated surface may be impaired. In addition, there is a problem that the stability of the emulsion is impaired during circulation, and the silicone oil in the emulsion is separated and precipitated, resulting in an uneven coating amount.

[0004]

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by controlling the amount of emulsifier in the silicone emulsion, the foaming property was suppressed,
Furthermore, they have found that by adding an appropriate amount of polyhydric alcohol, the mechanical stability can be improved without lowering the surface tension, and the present invention has been achieved. That is, the present invention comprises the following (A) to (D) as main components, and 50% deionized water.
This is a silicone emulsion having a surface tension at 25 ° C of 45 dyne / cm or more when diluted twice. (A) 10 to 60% by weight of a diorganopolysiloxane represented by the following formula [Chemical Formula 2] having a viscosity at 25 ° C of 100 to 1,000,000 centipoise.

Embedded image [Wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms and / or OR ³ (R ³ Is a hydroxyl group or an alkoxy group represented by hydrogen or an alkyl group having 1 to 6 carbon atoms), and m is a positive integer of 50 to 2,500.] (B) Anionic emulsifier 0.1 to 10% by weight (C) Polyhydric alcohol 1-20% by weight (D) Water balance

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The organopolysiloxane (A) used in the present invention is represented by the formula [Chemical Formula 2].
Examples of monovalent hydrocarbon groups R ¹ and R ² consisting of, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl,
Alkyl groups such as tetradecyl, hexadecyl, octadecyl, and eicosyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl and tolyl; alkenyl groups such as vinyl and allyl; And substituted groups. Among them, a methyl group, an ethyl group, a phenyl group and the like are preferable. Further, an alkyl group R having 1 to 6 carbon atoms
³ is methyl, ethyl, propyl, butyl, pentyl,
It is a hexyl group. In particular, it is preferable that 90 mol% or more of R ¹ and R ² is a methyl group.

The viscosity of this organopolysiloxane at 25 ° C. is 100 to 1,000,000 centipoise. this is
If the viscosity is lower than 100 centipoise, sufficient releasability cannot be imparted. If the viscosity is higher than 1,000,000 centipoise, the stability of the emulsion is reduced. More preferably, it is in the range of 1,000 to 100,000 centipoise. The compounding amount of the organopolysiloxane (A) is 10 to 60.
When the amount is less than 10% by weight, sufficient releasability cannot be imparted, and when the amount exceeds 60% by weight, the emulsion becomes unstable. More preferably, it is in the range of 20 to 40% by weight.

Examples of the anionic emulsifier (B) include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dialkylsulfosuccinate, potassium alkylphosphate, sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene lauryl ether sulfate. Examples thereof include sodium oxyethylene alkylphenyl ether sulfate and sodium polyoxyethylene tridecyl ether sulfate. These can be used alone or in combination of two or more. The amount of the anionic emulsifier (B) is from 0.1 to 10% by weight. If the amount is less than 0.1% by weight, the stability of the emulsion becomes insufficient. This is because the tension becomes small and foaming becomes remarkable.
More preferably, it is in the range of 1 to 5% by weight.

Examples of the polyhydric alcohol (C) include glycerin, diglycerin, polyglycerin, pentaerythritol, ethylene glycol, polyethylene glycol, trimethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butyl glycol. Butylene glycol, 1,4-butylene glycol, tetramethylene glycol, 2,3-butylene glycol, pentamethylene glycol, hexylene glycol, trimethylolpropane, 1,2,6-hexanetriol, xylitol, sorbitol, mannitol, diethylene glycol, Dipropylene glycol, tetraethylene glycol, triglycerin, tetraglycerin, ethylene glycol monooleyl ether, hexaglycerin, octaglycerin Decaglycerol, decaglycerol monolaurate, include decaglycerol dioleate. These can be used alone or in combination of two or more.

The compounding amount of the polyhydric alcohol (C) is from 1 to 20.
When the amount is less than 1% by weight, the effect of imparting stability is not sufficient, and when it exceeds 20% by weight, the effect of imparting releasability is impaired. More preferably, it is in the range of 3 to 10% by weight.

[0010] The silicone emulsion of the present invention is deionized water
Surface tension at 25 ° C when diluted 50 times is 45dyne / cm
It is necessary to be above. If the surface tension is lower than 45 dyne / cm, foaming is likely to occur. Preferably 50d
yne / cm or more. In the most preferred embodiment of the present invention, (A), (B) and (D) are obtained in a state of forming an anionic emulsion polymer. The anionic emulsion polymer can be produced by, for example, a method of polymerizing an organosiloxane in an aqueous medium using a strong acid or a strong alkali as a polymerization catalyst (Japanese Patent Publication No. 34-2041), alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid,
A method of polymerizing an organosiloxane in an aqueous medium using an aliphatic sulfonic acid, a silylalkyl sulfonic acid, an aliphatic substituted diphenyl ether sulfonic acid, an alkyl hydrogen sulfate or the like as a polymerization catalyst (Japanese Patent Publication No. 41-13995, Belgian Patent No. 686812, US Pat. No. 3,334,091) or 3 to 6 of diorganosiloxane in an aqueous solution of a salt type surfactant.
By emulsifying and dispersing the polymer, adding an ion-exchange resin to the dispersion, and performing ion exchange on the salt-type surfactant, and polymerizing the diorganosiloxane in an aqueous medium (Japanese Patent Publication No.
No. -19440). In the case (C), the compound may be added to the anionic emulsion polymer. Further, various additives such as an antifogging agent, an antistatic agent and a preservative can be added to the silicone emulsion of the present invention without departing from the scope of the present invention.

[0011]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. The viscosities in the examples are values at 25 ° C. The silicone emulsions obtained in Examples 1 to 7 and Comparative Examples 1 to 3 shown below were each diluted 50 times with deionized water, and the following characteristics were measured. The results are shown in Table 1. In addition, the compounding quantity in a table | surface is a weight%.

(1) Measurement of surface tension Sensa Dyne6000 liquid surface tensiometer (Chem-Dyne Research C)
Orporation) at 25 ° C. (2) Measurement of mechanical stability 1.2L juicer mixer [Hitachi Mixer (VA-W26)
500 g), stirred at 9,000 rpm for 30 seconds, and then transferred to a 1 L poly-jug. The mixture was allowed to stand at 25 ° C. for about 1 hour, and the state of the liquid surface after disappearance of the bubbles was visually observed. The judgment was made based on the following criteria. ：: No change from before test (before stirring). Δ: There is an oil spot. ×: Separated into two phases. (3) Measurement of foaming property Put 100 g into a 1 L measuring cylinder, air bubbling (1.0 L / min), and measure the time until the foam volume becomes 1,000 ml. The longer the time, the less likely it is to foam. (4) Measurement of releasability A polystyrene sheet was hand-coated with paper gauze, dried at room temperature for 3 hours, and then autographed (“DSC-500”).
Dynamic friction coefficient was measured by Shimadzu Corporation. (Vs. SB
R rubber / load 200g / pulling speed 100mm / min)

Example 1 100 g of a 10% aqueous solution of dodecylbenzenesulfonic acid was gradually added dropwise to a mixture of 300 g of octamethylcyclotetrasiloxane and 0.86 g of hexamethyldisiloxane while stirring at 1,000 rpm with a homomixer. After phase inversion and thickening, the stirring speed was increased to 5,000 rpm to 15
After stirring for minutes, the mixture was diluted by adding 50 g of a 10% aqueous solution of dodecylbenzenesulfonic acid and 454 g of deionized water. Next, this was treated twice with a high-pressure homogenizer at a pressure of 300 kg / cm ² , and then allowed to stand at 50 ° C. for 20 hours and further at 20 ° C. for 20 hours. Then add 46 g of 10% aqueous sodium carbonate solution and adjust the pH.
After adjusting to 7, glycerin (50 g) was added as (C), and the mixture was stirred at 1,000 rpm for 15 minutes with a homomixer to obtain a milky white emulsion. This emulsion did not show any phase separation even after being left at room temperature for one month, and showed excellent stability. 300 g of isopropyl alcohol was added to 200 g of this emulsion, oil was extracted, washed with water and dried, and the resulting dimethylpolysiloxane had a viscosity of 9,800 cP at 25 ° C.

Example 2 A mixture of 300 g of octamethylcyclotetrasiloxane and 2.2 g of hexamethyldisiloxane was mixed with 100 g of a 10% aqueous solution of lauryl sulfate using a homomixer for 1,000 r.
The mixture was gradually added dropwise while stirring at pm. After inverting the phase and increasing the viscosity, increase the stirring speed to 5,000 rpm and stir for 15 minutes.
100 g of an aqueous solution of lauryl sulfate and 368 g of deionized water were added for dilution. Next, this was subjected to 300 kg / cm ² with a high-pressure homogenizer.
After treating twice at a pressure of 20 ° C, let it stand at 50 ° C for 20 hours,
For 20 hours. Then a 10% aqueous sodium carbonate solution
After adjusting the pH to 7 by adding 80 g, 50 g of propylene glycol was added as (C), and the mixture was homogenized with a homomixer for 15 minutes at 1,000 ml.
By stirring at 0 rpm, a milky white emulsion was obtained. This emulsion did not show any phase separation even after being left at room temperature for one month, and showed excellent stability. 300 g of isopropyl alcohol was added to 200 g of this emulsion, oil was extracted, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane was 25.
It was 1,100 cP at ° C.

Example 3 To a mixture of 300 g of octamethylcyclotetrasiloxane and 0.86 g of hexamethyldisiloxane, 100 g of a 10% aqueous solution of dodecylbenzenesulfonic acid was gradually dropped with a homomixer at 1,000 rpm while stirring. After phase inversion and thickening, the stirring speed was increased to 5,000 rpm to 15
After stirring for minutes, 200 g of a 10% aqueous solution of dodecylbenzenesulfonic acid and 207 g of deionized water were added for dilution. Next, this was treated twice with a high-pressure homogenizer at a pressure of 300 kg / cm ² , and then allowed to stand at 50 ° C. for 20 hours and further at 20 ° C. for 20 hours. Then add 93g of 10% aqueous sodium carbonate solution
After the pH was adjusted to 7, 100 g of glycerin was added as (C), and the mixture was stirred with a homomixer at 1,000 rpm for 15 minutes to obtain a milky white emulsion. This emulsion did not show any phase separation even after being left at room temperature for one month, and showed excellent stability. Oil was extracted by adding 300 g of isopropyl alcohol to 200 g of this emulsion, washed with water and dried, and the viscosity of dimethylpolysiloxane obtained at 25 ° C. was 10,200 cP.

EXAMPLE 4 50 g of a 10% aqueous solution of dodecylbenzenesulfonic acid and 50 g of deionized water were gradually added to a mixture of 300 g of octamethylcyclotetrasiloxane and 0.86 g of hexamethyldisiloxane while stirring at 1,000 rpm with a homomixer. did. After phase inversion and thickening, the stirring speed was reduced.
After stirring at 5,000 rpm for 15 minutes, 575 g of deionized water was added for dilution. Then, this is mixed with a high-pressure homogenizer for 3 hours.
After treatment twice at a pressure of 00 kg / cm ^2, the mixture was allowed to stand at 50 ° C. for 20 hours,
Furthermore, it left still at 20 degreeC for 20 hours. Next, 15 g of a 10% aqueous sodium carbonate solution was added to adjust the pH to 7, and then 10 g of glycerin was added as (C), and the mixture was mixed with a homomixer for 15 minutes at 1,000 rpm.
The mixture was stirred at pm to obtain a milky white emulsion. This emulsion did not show any phase separation even after being left at room temperature for one month, and showed excellent stability. Add 200 g of this emulsion to isopropyl alcohol
The oil was extracted by adding 300 g, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane was 9,600 at 25 ° C.
cP.

Example 5 To a mixture of 400 g of octamethylcyclotetrasiloxane and 5.7 g of hexamethyldisiloxane, 100 g of a 10% aqueous solution of lauryl sulfuric acid was slowly dropped with a homomixer at low speed. After phase inversion and thickening,
Increase the stirring speed to 5,000rpm and then high-speed stirring for 15 minutes, then 10%
The solution was diluted by adding 100 g of an aqueous solution of lauryl sulfate and 264 g of deionized water. Next, this was subjected to 300 kg / cm ² with a high-pressure homogenizer.
After treating twice at a pressure of 50 ° C, let it stand at 50 ° C for 20 hours,
The mixture was allowed to stand at 200C for 20 hours. Next, 80 g of a 10% aqueous solution of sodium carbonate was added to adjust the pH to 7, and then (C) was 1,3.
-Add 50 g of butylene glycol and mix with a homomixer
The mixture was stirred at 1,000 rpm for 1 minute to obtain a milky white emulsion. Even if this emulsion was left at room temperature for one month, no layer separation was observed,
It showed excellent stability. Oil was extracted by adding 300 g of isopropyl alcohol to 200 g of this emulsion, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane was 320 cP at 25 ° C.

Example 6 A mixture of 400 g of octamethylcyclotetrasiloxane and 0.38 g of hexamethyldisiloxane was slowly dropped with 100 g of a 10% aqueous solution of lauryl sulfate while being stirred at a low speed with a homomixer. After phase inversion and thickening, after increasing the stirring speed to 5,000 rpm and high-speed stirring for 15 minutes
The mixture was diluted by adding 100 g of a 10% aqueous solution of lauryl sulfate and 270 g of deionized water. Then this is 300kg with high pressure homogenizer
After treating twice at a pressure of / cm ^2, the mixture was allowed to stand at 50 ° C. for 20 hours and further at 20 ° C. for 20 hours. Next, 80 g of a 10% aqueous sodium carbonate solution was added to adjust the pH to 7, then 50 g of ethylene glycol was added as (C), and the mixture was homogenized with a homomixer for 15 minutes.
The mixture was stirred at 1,000 rpm to obtain a milky white emulsion. This emulsion did not show any phase separation even after being left at room temperature for one month, and showed excellent stability. To 200 g of this emulsion, 300 g of isopropyl alcohol was added to extract the oil, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane was 25 ° C.
It was 102,000 cP.

Example 7 100 g of a 10% aqueous solution of dodecylbenzenesulfonic acid was gradually added dropwise to a mixture of 100 g of octamethylcyclotetrasiloxane and 2.2 g of hexamethyldisiloxane while stirring at a low speed with a homomixer. Phase inversion,
After thickening, the stirring speed was increased to 5,000 rpm, and the mixture was stirred for 15 minutes, and then diluted by adding 50 g of a 10% aqueous solution of dodecylbenzenesulfonic acid and 652 g of deionized water. Next, this was treated twice with a high-pressure homogenizer at 300 kg / cm ² ,
The mixture was allowed to stand for 20 hours and then at 20 ° C. for 20 hours. Next, after adjusting the pH to 7 by adding 46 g of a 10% aqueous sodium carbonate solution,
Add 50g of glycerin as (C) and use a homomixer
By stirring at a speed of 1,000 rpm for 15 minutes, a milky white emulsion was obtained. This emulsion did not show any phase separation even after being left at room temperature for one month, and showed excellent stability. Oil was extracted by adding 300 g of isopropyl alcohol to 200 g of this emulsion, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane was 950 cP at 25 ° C.

Comparative Example 1 A milky white emulsion was obtained in exactly the same manner as in Example 1 except that 504 g of deionized water was used and glycerin was not added. Even if this emulsion was allowed to stand at room temperature for one month, no phase separation was observed, and the emulsion was highly stable. Add 200 g of this emulsion to isopropyl alcohol
The oil was extracted by adding 300 g, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane was 9,800 at 25 ° C.
cP.

Comparative Example 2 100 g of a 30% aqueous solution of dodecylbenzenesulfonic acid was gradually added dropwise to a mixture of 300 g of octamethylcyclotetrasiloxane and 0.86 g of hexamethyldisiloxane while stirring at a low speed with a homomixer. After phase inversion and thickening, the stirring speed was increased to 5,000 rpm and the mixture was stirred for 15 minutes, and then 30% dodecylbenzenesulfonic acid aqueous solution 30
0 g and deionized water 126 g were added for dilution. Next, this was treated twice with a high-pressure homogenizer at a pressure of 300 kg / cm ² , and then allowed to stand at 50 ° C. for 20 hours and further at 20 ° C. for 20 hours. Then, 124 g of a 30% aqueous sodium carbonate solution was added to adjust the pH to 7, and 50 g of glycerin was added as (C), followed by stirring at 1,000 rpm for 15 minutes with a homomixer to obtain a milky white emulsion. Even if this emulsion was allowed to stand at room temperature for one month, no phase separation was observed, and the emulsion was highly stable. This emulsion 20
Oil was extracted by adding 300 g of isopropyl alcohol to 0 g, washed with water and dried, and the viscosity of the obtained dimethylpolysiloxane at 25 ° C. was 11,300 cP.

Comparative Example 3 A milky white emulsion was obtained in exactly the same manner as in Example 1 except that the amount of deionized water was changed to 254 g and the amount of glycerin was changed to 250 g. Even if this emulsion was allowed to stand at room temperature for one month, no phase separation was observed, and the emulsion was highly stable. Oil was extracted by adding 300 g of isopropyl alcohol to 200 g of this emulsion, washed with water and dried, and the viscosity of dimethylpolysiloxane obtained at 25 ° C. was 9,700 cP.

Comparative Example 4 To a mixture of 300 g of octamethylcyclotetrasiloxane and 0.86 g of hexamethyldisiloxane, 7 g of a 10% aqueous solution of dodecylbenzenesulfonic acid and 100 g of deionized water were gradually dropped with a homomixer at low speed while stirring. After phase inversion and thickening, the stirring speed is 5,000r
After raising to pm and stirring for 15 minutes, 587 g of deionized water was added for dilution. Next, this is 300 kg / c with a high-pressure homogenizer.
After treatment twice at a pressure of m ^2, the mixture was allowed to stand at 50 ° C for 20 hours,
The mixture was allowed to stand at 20 ° C. for 20 hours, but the experiment was stopped because two-layer separation occurred and oil precipitated.

In Examples 1 to 7, the surface tension of the 50-fold diluent was
Since it was at least 45 dyne / cm, the foaming test showed that the foamability was low for 2 minutes or more in all cases. Good stability was also exhibited in the mechanical stability test. Comparative Example 1 was inferior in mechanical stability because the polyhydric alcohol of (C) was not blended. In Comparative Example 2, since the amount of (B) is too large, the foaming amount is large, and troubles in the process are expected. In Comparative Example 3, it was found that the amount of (C) was too large, the dynamic friction coefficient was high, and the releasability was reduced.

[0025]

[Table 1]

[0026]

As described above, when the emulsion of the present invention is used as a release agent, foaming is low due to low foaming property, bubbling during circulation of the release agent by a pump is reduced, and the process can be made more efficient. Can be applied uniformly.

Claims (2)

[Claims] The present invention comprises the following components (A) to (D) as main components, and has a surface tension of 4 at 25 ° C. when diluted 50 times with deionized water.
A silicone emulsion having a viscosity of 5 dyne / cm or more. (A) 10 to 60% by weight of a diorganopolysiloxane represented by the following general formula [1] having a viscosity at 25 ° C. of 100 to 1,000,000 centipoise: [Wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms and / or OR ³ (R ³ Is a hydroxyl group or an alkoxy group represented by hydrogen or an alkyl group having 1 to 6 carbon atoms), m is a positive integer of 50 to 2,500] (B) Anionic emulsifier 0.1 to 10% by weight (C) Polyhydric alcohol 1-20% by weight (D) Water balance 2. The silicone emulsion according to claim 1, wherein (A), (B) and (D) form an anionic emulsion polymer.