KR100352560B1 - Silicone Composition For Release Agent - Google Patents

Abstract

The present invention relates to diorganopolysiloxane containing 0.15 to 3 mol% of vinyl groups in one molecule of (A), and having a viscosity at 25 ° C of 30 wt% toluene solution at 1,000 to 100,000 centipoise,

(B) contains at least three hydrogen atoms bonded to silicon atoms in one molecule, and contains 10 to 50 mol% of R ₂ SiO units, wherein R is a homogeneous or heterogeneous monovalent hydrocarbon group, and (A Organohydrogenpolysiloxane in which the amount of SiH groups to the vinyl groups of the component) is from 2 to 5 in a molar ratio,

(C) platinum group metal catalysts

It contains, and the rubber hardness after hardening is 55-85 with an Asuka-hardness meter, The silicone composition for releasing agents is provided.

The silicone composition of this invention is excellent in sclerosis | hardenability, provides the silicone hardened | cured film excellent in the fall of residual adhesive rate, and excellent in air exposure resistance, and has the outstanding performance as a peeling agent.

Description

Silicone composition for release agent

The present invention relates to a silicone composition for release agent of an addition-reactive solvent type that provides a peelable silicone cured coating that is excellent in curability, has a low drop in residual adhesion, and is excellent in air exposure resistance.

The adhesive label, adhesive tape, etc. before use are protected by release paper, and at the time of use, the release paper is peeled off and used. As the release agent used for the release paper, there are mainly three kinds of silicone-based, polyolefin-based and paraffin-based resins, and the fluorine-based resin also becomes an excellent release agent. The release agent was strongly fixed to one side of the substrate, and the treated solid surface was oriented with -CH ₃ , -CH _2- , -CF ₃ , -CF ₂ -segments, so that the surface energy of the solid was about 20 dyn / cm or It becomes less than that and becomes difficult to peel off. A release agent is mainly used for adhesive products, such as adhesive labels and double-sided tapes, and is also used for the packaging of asphalt, rubber | gum, confectionery, food, etc., process papers, such as manufacture of synthetic leather, baking of food, etc.

As described above, one of the methods of preventing adhesion or adhesion between a base material such as paper or a plastic film and an adhesive substance has been conventionally performed to form a cured coating film of a silicone composition on the base material surface to impart peeling properties.

In this case, as a method of forming a silicon film on the surface of a base material,

(1) a method of forming a peelable film by further reacting an organopolysiloxane containing an aliphatic unsaturated group with an organohydrogen polysiloxane using a platinum compound as a catalyst;

(2) A method of forming a peelable film by condensing an organopolysiloxane using an organic acid metal salt catalyst such as an organic tin compound

Etc. are known.

Any silicone composition used in these methods is called a thermosetting type for forming a film by heating, and is a type dissolved in an organic solvent such as toluene, and a solvent-free type composed of only emulsion-type silicone that is emulsified according to its properties. Are classified.

In terms of productivity, the peelable film formed by the first method having a faster curing rate than the second method is widely used. However, when the substrate on which the silicon cured film has been formed is exposed to air, peeling between the adhesive product and the substrate becomes difficult and extreme. In this case, there is a problem that the adhesive product does not peel off from the substrate. This is presumed to be caused by the adhesion of dust in the air to the silicone cured film, and the air exposure resistance is also important for the stable production of the adhesive product and the repeated use of the silicone cured film-forming substrate.

In general, the cured coating made of an addition-reactive silicone composition is inferior in air exposure resistance compared to the cured coating made of a condensation-responsive silicone composition, and the cured coating made of a solvent-type silicone composition has an emulsion type or a solvent-free composition. The air exposure resistance is lower than the film made of.

Therefore, in the silicone composition of the addition-response solvent type, silicone curing is performed by excessively adding a component (so-called transition component) that does not contain a reactive substituent and bringing in dust attached to the cured film formed of this composition into the transition component. Although the method of improving the air exposure resistance of a film is also employ | adopted, in this case, there exists a problem of generating disadvantages, such as a migration problem, such as roll contamination and a printing defect, or an extreme fall of the adhesive force of an adhesive.

This invention is made | formed in view of the said situation, The silicone composition for the peeling agent of the addition reaction type | mold solvent type which provides the peelable silicone cured film which is excellent in sclerosis | hardenability, there is little fall of residual adhesive rate, and is excellent in air exposure resistance. It aims to provide.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, (A) it contains 0.15-3 mol% of vinyl groups with respect to the whole organic group in 1 molecule, and the conductivity in 25 of a 30 weight% toluene solution is 1,000-100,000 centipoise. Phosphorous diorganopolysiloxane, (B) contains at least three hydrogen atoms bonded to silicon atoms in one molecule, and contains 10 to 50 mol% of R ₂ SiO units (where R is the same or different monovalent hydrocarbon group). And adding an organohydrogenpolysiloxane having an amount of SiH groups to a vinyl group of component (A) of 2 to 5 in a molar ratio, and (C) a platinum group metal catalyst, compared with conventional silicone composition of the addition reaction type solvent type. Since the reactivity is excellent, the amount of functional groups (vinyl group) remaining in the elapsed coating film obtained by this composition can be reduced, and thus the possibility of dust adhesion due to the charging of the vinyl group is small. Since the cured film is hard (rubber hardness of 55 to 85 by the Asuka-Hardometer), it is possible to prevent dust from infiltrating into the cured film and to provide a cured film with greatly improved air exposure resistance. Therefore, the present inventors have found that heavy peeling trouble due to air exposure of a substrate on which a silicone cured film is formed during adhesion processing can be prevented, and productivity and quality control can be improved.

Therefore, the present invention

(A) Diorganopolysiloxane containing 0.15 to 3 mol% of vinyl groups relative to the entire organic group in one molecule, and having a viscosity at 25 to 30% by weight of a toluene solution of 1,000 to 100,000 centipoise,

(B) contains at least three hydrogen atoms bonded to silicon atoms in one molecule, contains 10 to 50 mol% of R ₂ SiO units (where R is the same or different monovalent hydrocarbon group), and (A) Organohydrogenpolysiloxane in which the amount of SiH groups to the vinyl group of the component is 2 to 5 in a molar ratio,

(C) platinum group metal catalysts

And a rubber hardness after curing is 55 to 85 in an Asuka-hardness meter, to provide a silicone composition for release agent.

Hereinafter, the present invention will be described in more detail, the diorganopolysiloxane of component (A) contains from 0.15 to 3 mol%, particularly preferably from 0.2 to 2% by weight of vinyl groups, 30 wt% toluene, based on the total organic groups in one molecule. The viscosity at 25 of the solution is 1,000 to 100,000 centipoise (cp).

When the diorganopolysiloxane has a vinyl group content of less than 0.15 mol%, the curability is poor, and the obtained cured film is relatively soft. Therefore, the desired excellent air exposure resistance is not obtained. When the vinyl group content exceeds 3 mol%, Peeling resistance becomes large and it becomes impossible to obtain the outstanding peeling performance. If the viscosity at 25 of the 30% by weight toluene solution is lower than 1,000 cp, an operational closure of dissolving the organopolysiloxane in toluene occurs. If the viscosity is higher than 100,000 cp, the synthesis of such organopolysiloxane becomes difficult.

In the organopolysiloxane of the said (A) component, although organic groups other than a vinyl group are mentioned, alkyl groups, such as a methyl group, an ethyl group, and a propyl group, aryl groups, such as a phenyl group and a tolyl group, etc. are mentioned, In terms of sclerosis | hardenability and peelability improvement It is preferable that 80 mol% or more is a methyl group. In addition, the terminal of the molecule of the diorganopolysiloxane may be any of a hydroxyl group, an alkyl group, a vinyl group, and the like, but in terms of curability, the vinyl group is preferable, and the molecular shape is preferably linear, but even in a branched state. good.

The organohydrogenpolysiloxane of component (B) contains at least three or more hydrogen atoms bonded to silicon atoms in one molecule, and contains 10 to 50 moles of R ₂ SiO units (R is a homogeneous or heterogeneous monovalent hydrocarbon group). % Is contained, and this SiH group and the vinyl group in (4) component add-react and a hardened film is formed.

Here, as said R, alkyl groups, such as a methyl group, an ethyl group, and a propyl group, aryl groups, such as a phenyl group and a tolyl group, etc. are mentioned, It is preferable that it is a methyl group from a point of improving an addition reaction rate.

Moreover, although other organic groups other than the hydrogen atom couple | bonded with the silicon atom are the same as said R, it is preferable that 90 mol% or more is a methyl group.

As such organohydrogenpolysiloxane, what is represented by following formula (1), (2) is mentioned.

(Wherein m and n are integers and m ≥ 3)

(Wherein p and q are integers and p ≧ 1)

In the above formula, n / (m + n) and q / (p + q) are each preferably in the range of 0.1 to 0.5, particularly 0.2 to 0.5. When n / (m + n) and q / (p + q) are less than 0.1, it is difficult for the organopolysiloxane to react effectively with vinyl groups, so that excellent air exposure resistance, which is an object of the present invention, is not obtained, and n If / (m + n) and q / (p + q) are more than 0.5, air exposure resistance is good, but there is a disadvantage that the adhesion to the substrate is deteriorated.

The organohydrogenpolysiloxane of component (B) may be linear or branched, and the viscosity at 25 is preferably 10 to 1,000 cp.

(B) but as long as according to the vinyl group amount by which the amount of the component contained in the component (A), curing the coating to form, as seen from the peeling performance point of view, the ratio of SiH / SiCH = CH ₂ is it is necessary to from 2 to 5 Especially, it is preferable to set it as 2.5-4.5. When this ratio is less than 2, since the cured film becomes relatively soft, air exposure resistance deteriorates, and when it exceeds 5, peeling resistance becomes large.

The platinum group metal catalyst of the component (C) is a catalyst for promoting the addition reaction of the component (A) and the component (B), and a known one is used as the addition reaction catalyst. As such a platinum group metal catalyst, catalysts, such as a platinum type, a palladium type, a rhodium type, are mentioned, for example, A platinum type catalyst is especially preferable among these. As such a platinum-type catalyst, complexes with the chloroplatinic acid, the alcohol solution of chloroplatinic acid, an aldehyde solution, various olefins of chloroplatinic acid, or vinylsiloxane, etc. are mentioned, for example.

Although the addition amount of these platinum group metal catalysts is a catalytic amount, it is good to obtain a favorable hardened film and, from an economical viewpoint, to set it as the amount of platinum group metals with respect to 100 parts (weight part or less) of (A) component in the range of 1-1,000 ppm. desirable.

Although the composition of this invention is obtained by mix | blending the predetermined amount of said (A)-(C) component, in addition to each said component, in order to suppress the catalytic activity of the following arbitrary components, for example, a platinum group metal type catalyst, various organic nitrogen Activity inhibitors, such as a compound, an organophosphorus compound, an acetylene type compound, an oxime compound, and an organic chloro compound, the diorganopolysiloxane which does not contain the hydrogen atom or vinyl group couple | bonded with the silicon atom for the purpose of controlling peeling force, etc. are added as needed. can do. In addition, the addition amount of an optional component can be used as a normal amount in the range which does not prevent the effect of this invention.

In preparation of the silicone composition of this invention, it is preferable to mix (A), (B) component, and arbitrary components beforehand, and then add (C) component, and each component is used individually or 2 types You may use the above together. Moreover, you may melt | dissolve in organic solvents, such as toluene, xylene, and n-hexane, as needed.

The silicone composition thus prepared is applied to a substrate, such as paper or plastic film, for example, and then heat cured by a conventional method. Asuka-C hardness of the cured film formed according to heat-hardening is 55-85, and the base material with a cured film of the composition of this invention is used suitably as a release paper.

The silicone composition of this invention is excellent in sclerosis | hardenability, the fall of the residual adhesive rate is small, and it is providing the silicone cured film excellent in the air exposure resistance, and has the outstanding performance as a peeling agent.

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example. In addition, all the parts in each case are a weight part, and a viscosity is a value in 25.

Moreover, curability, peeling force, residual adhesiveness, air exposure resistance, and cured film hardness of the silicone composition were measured by the following method.

Curable

The silicone composition was applied to a thin film or sheet-like substrate surface by a predetermined amount, and the cured film formed by heating in a hot air dryer at a predetermined temperature was rubbed several times with a finger, and the time until a state without blur and dropout was measured. .

Peel force

The silicone composition is applied to a thin film or sheet-like substrate surface in a predetermined amount and heated in a hot air dryer at a predetermined temperature to form a cured film. The cured film is then coated with an acrylic solvent-type adhesive oline BPS-5 / 27 [ Toyo Inki Seijo Co., Ltd.] was applied and heated at 100 to 3 minutes. Next, a good weight paper having a basis weight of 64 g / m ² is pasted to this treated surface, aged for 25 to 20 hours, the sample is cut to a width of 5 cm, and the peel rate is 0.3 m / at a 180 degree angle using a tensile tester. The force (g) required to pull off and peel off the pasted paper at minutes and 60 m / min was measured.

Residual adhesion

A polyester tape (trade name: Lumiler 31B, manufactured by Nendodo Co., Ltd.) was attached to the surface of the cured coating film of the silicone composition formed on the surface of the substrate in the same manner as in the case of the peel force measurement, and 20 g / cm ^After aging at 70 to 20 hours with a load of ² , the tape was peeled off and attached to the stainless plate Next, the tape was peeled off at a 180 degree angle from the stainless plate at a peel rate of 0.3 m / min and needed to peel off. The force (g) was also measured, and the force (g) necessary for attaching the tape to the Teflon plate and peeling the treated tape from the stainless plate in the same manner was also measured.

Air exposure

As in the case of peeling force measurement, the cured film of the silicone composition formed on the surface of the substrate was exposed in the air for 3 to 16 hours in the room, and then the force required to peel each peeling rate at 0.3 m / min in the same manner as the peeling force measurement. (g) was measured and the peel force change by air exposure was investigated.

Cured Film Hardness

The silicone composition was heated in a hot air dryer at a predetermined temperature for a predetermined time to form a rubber cured film having a predetermined thickness, and then cured by using an Asuka-C rubber hardness meter (manufactured by Kobunshi Gauge Co., Ltd.). The hardness was measured.

Example 1

Dimethylpolysiloxane (blocked at both ends of the molecular chain with dimethylvinylsiloxy groups, containing 3 mol% of methylvinylsiloxane units and having a 30% toluene melt viscosity of 5,000 cp) (content of vinyl groups relative to the total organic group of 1.5 mol%) 100 Parts are dissolved in 2,000 parts of toluene, and 9.2 parts of methylhydrogenpolysiloxane having a viscosity of 45 cp (SiH / SiCH = CH ₂₎ containing 25 mol% of dimethylsiloxane units at both ends of the molecular chain and sealed with a trimethylsiloxy group. = 2.5), then 3 parts of 1,1-dimethyl-2-propenyloxytrimethylsilane was added and stirred until uniform, and then the complex of platinum and vinyl siloxane was converted to 200 ppm in terms of platinum to the dimethylpolysiloxane. The silicone composition was prepared by adding as much as possible.

Next, 0.7-0.8 g / m <^{2> is} apply | coated to the polyethylene laminated paper (Basic weight 100 g / m <^2> ) as a solid content, and the peeling force, residual adhesiveness, and air exposure property are set at 100 with respect to the sample for a hardenability test. The test sample was heat-treated for 140 to 30 seconds to form a cured film. Furthermore, after toluene was air-dried over 25 to 20 hours so that thickness might be 12 mm, it heat-processed for 120 to 20 minutes, the rubber sheet was produced, it was set as the sample for hardened film hardness measurement, and Asuka-C hardness was measured. These measurement results are shown in Table 1.

Example 2

Instead of the dimethylpolysiloxane used in Example 1, the dimethylpolysiloxane having a molecular chain terminal blockade of dimethylvinylsiloxy groups, containing 0.5 mol% of methylvinylsiloxane units, and 10,000 cp of 30% toluene dissolving viscosity (vinyl group to all organic groups) Was prepared in the same manner as in Example 1 except that the compounding rate of 0.25 mol%) was 100 parts and the amount of the methylhydrogenpolysiloxane used in Example 1 was 5.5 parts (SiH / SiCH = CH ₂ = 4.5). In the same manner as in Example 1, the physical properties were tested. The results are written together in Table 1.

Example 3

In place of the dimethylpolysiloxane used in Example 1, the dimethylpolysiloxane having a molecular chain terminal sealed with a dimethylvinylsiloxy group and containing 1.2 mol% of methylvinylsiloxane units and having a 30% toluene dissolution viscosity of 4,500 cp The compounding quantity of the methylhydrogenpolysiloxane used in Example 1 using 85 parts of content rates of 0.6 mol%), and 15 parts of dimethyl polysiloxane whose both ends of a molecular chain are sealed by the trimethylsiloxy group, and 30% toluene melt viscosity is 20,000cp. A silicone composition was prepared in the same manner as in Example 1 except that the amount thereof was 4.4 parts (SiH / SiCH = CH ₂ = 3.5), and the same physical properties test as in Example 1 were performed. The results are written together in Table 1.

Comparative Example 1

A silicone composition was prepared in the same manner as in Example 1 except that the compounding amount of methylhydrogenpolysiloxane used in Example 1 was 5.5 parts (SiH / SiCH = CH ₂ = 1.5).

Comparative Example 2

Instead of the methylhydrogenpolysiloxane used in Example 1, except that both ends of the molecular chain were sealed with a trimethylsiloxy group, and 6.4 parts (SiH / SiCH = CH ₂ = 2.5) of methylhydrogenpolysiloxane having a viscosity of 20 cp was added. In the same manner as in Example 1, a silicone composition was prepared, and the same physical properties test as in Example 1 were performed. The results are written together in Table 1.

Comparative Example 3

Instead of methylhydrogenpolysiloxane used in Example 1, 16.0 parts of methylhydrogenpolysiloxane having both ends of the molecular chain are sealed with trimethylsiloxy group, containing 60 mol% of dimethylsiloxane units, and having a viscosity of 150 cp (SiH / SiCH = CH ₂ = 2.5) A silicone composition was prepared in the same manner as in Example 1 except for blending, and the same physical properties tests as in Example 1 were performed. The results are written together in Table 1.

Comparative Example 4

A silicone composition was prepared in the same manner as in Example 1 except that the compounding amount of methylhydrogenpolysiloxane used in Example 1 was 22.1 parts (SiH / SiCH = CH ₂ = 6), and the same physical properties test as in Example 1 were performed. It was. The results are written together in Table 1.

Table 1

Claims (1)

(A) Diorganopolysiloxane which contains 0.15 to 3 mol% of vinyl groups with respect to the whole organic group in 1 molecule, and whose viscosity at 25 of a 30 weight% toluene solution is 1,000 to 100,000 centipoise, (B) contains at least three hydrogen atoms bonded to silicon atoms in one molecule, and contains 10 to 50 mol% of R ₂ SiO units, wherein R is a homogeneous or heterogeneous monovalent hydrocarbon group, and (A Organohydrogenpolysiloxane in which the amount of SiH groups to the vinyl groups of the component) is from 2 to 5 in a molar ratio, (C) platinum group metal catalysts And the rubber hardness after curing is 55 to 85 in an Asuka-hardness meter.