JPS6348901B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a silicone composition for mold release, and particularly to a silicone composition for mold release that does not deteriorate in mold release properties even when the coating amount is reduced and has a light peeling force. Conventionally, for the purpose of preventing adhesion or sticking between a base material such as paper, processed paper, or plastic film and an adhesive substance, a film of a silicone composition is formed on the surface of the base material, and then mold release is performed. The method of imparting gender is commonly used. Methods for forming this silicone film include (1) a method of forming a release film by a polycondensation reaction of organopolysiloxane using an organic acid metal salt catalyst such as an organotin compound; (2) a method of forming a release film using platinum or A method is known in which a release film is formed by adding an organohydrodiene polysiloxane and an organopolysiloxane containing an aliphatic unsaturated group using a platinum compound as a catalyst. This is called a heat cure type that forms a film, but depending on the properties of this silicone composition, it can also be a solvent type that is dissolved in an organic solvent such as toluene, an emulsion type that is made into an emulsion, and even It is classified as a solvent-free type made only of silicone. Formation of a releasable film using these silicone compositions is usually done by reverse roll coating, gravure roll coating, or air knife coating on the surface of the substrate such as paper or plastic film. This is done by applying a coating using a method such as a coating method, and although the amount of coating varies slightly depending on the type of substrate,
For example, for high-quality paper laminated with polyethylene, the silicone content is set to be 0.5 g/m ² or more. However, for this 0.5g/m ²
If the amount is less than that, the uncoated area of the silicone component will increase and its mold release properties will deteriorate rapidly, so it is industrially customary to apply a coating amount of around 0.8 g/ ^m2 . However, measures to reduce this amount of application are required from an economic standpoint.
There is a demand for a method to reduce this to 0.3 g/m ² , and industrially to 0.5 g/m ² . The present invention relates to a releasable silicone composition that can meet this demand, and includes (a) a unit formula in the molecular chain;

[Formula] (where R ¹ is an unsubstituted or substituted monovalent saturated hydrocarbon group, a and b are both integers of 1 or more and a+b≦3); ) unit formula in the molecular chain

[Formula] (where R ² is a monovalent aliphatic unsaturated hydrocarbon group, R ³ is an unsubstituted or substituted monovalent hydrocarbon group, c and d are both integers of 1 or more, and c
+d≦3) an aliphatic unsaturated group-containing organopolysiloxane having a siloxane unit, (c) one or more compounds having a perfluoroalkyl group having 4 to 20 carbon atoms, (d) platinum Alternatively, it is characterized by comprising one or more platinum compounds. To explain this, the present inventors have conducted various studies on ways to reduce the coating amount of the silicone composition for mold release described above, and found that, in particular, the addition reaction type silicone composition has a compound having a perfluoroalkyl group in its molecule. It has been found that the wettability of this composition to the substrate surface is improved by adding the composition, and as a result, even if the amount of the composition is reduced, the degree of deterioration of the mold releasability can be reduced. Through further research, it was discovered that if this perfluoroalkyl group has 4 to 20 carbon atoms, the effect will be particularly remarkable, and the lower limit of the coating amount can be lowered to 0.3 g/ ^m2 . After confirming this, the present invention was completed. The main ingredient of the silicone composition of the present invention may be a conventionally known addition-reaction type silicone composition, and therefore, it may contain the above-mentioned organohydrodiene polysiloxane as the component (a) and the aliphatic acid as the component (b). It consists of an organopolysiloxane containing an unsaturated hydrocarbon group and platinum or a platinum compound as component (d). This organohydrodiene polysiloxane as component (a) has the above unit formula in its molecular chain.

It is required to have a siloxane unit represented by the formula, but this
^R1 group is an alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, amyl group, aryl group such as phenyl group, biphenyl group, naphthyl group, alkaryl group such as tolyl group, xylyl group, ethyl phenyl group, etc. group, chloromethyl group,
Examples include halogenated alkyl groups and halogenated aryl groups such as chloroethyl group, chloropropyl group, fluoromethyl group, fluoroethyl group, fluoropropyl group, trifluoropropyl group, and monochlorophenyl group, where a, b is an integer greater than or equal to 1 and satisfies a+b≦3. In addition,
The molecular structure of this organohydrodiene polysiloxane is not particularly limited as long as it has a siloxane unit represented by the above unit formula in its molecular chain, and this may be a linear structure or a branched structure. It may be present, it may be partially cross-linked, or it may be a mixture of these. Next, the aliphatic unsaturated hydrocarbon group-containing organopolysiloxane as component (b) has the above-mentioned unit formula in its molecular chain.

It is required to have the unit formula shown by [formula], and this
R ² is an aliphatic unsaturated hydrocarbon group having a double bond or triple bond such as a vinyl group, allyl group, ethynyl group, etc., and R ³ is a saturated 1 group similar to R ¹ described above.
In the valent hydrocarbon group, c and d are each an integer of 1 or more, and c+d≦3. Furthermore, this aliphatic unsaturated hydrocarbon group-containing organopolysiloxane is not limited in its molecular structure as long as it contains a siloxane unit represented by the above unit formula in its molecular chain; , a branched structure, a partially cross-linked structure, or a mixture thereof. In addition, the molecular chain terminal of this substance may be either a hydroxyl group or a triorganosilyl group, but
This is preferably a dimethylvinylsilyl group due to its reactivity. This platinum or platinum compound as component (d) is
It is a known catalyst for promoting the addition reaction between component (a) and component (b), and includes platinum, chloroplatinic acid, a complex of chloroplatinic acid and olefin, chloroplatinic acid and vinyl Examples include reactants with group-containing organosilicon compounds. On the other hand, the perfluoroalkyl group-containing compound as component (c) constituting the composition of the present invention is essential for achieving the object of the present invention, and this is because the perfluoroalkyl group has 3 or less carbon atoms. , the effect of the addition is poor, and the number of carbon atoms is 21
If it is more than that, it will be difficult to synthesize it, and
Since the residual adhesion of the cured film obtained by applying a silicone composition containing this substance is reduced, it is necessary that the number of carbon atoms is 4 to 20, and this is due to its physical properties and synthetic surface. It is preferable to use a carbon atom having 8 to 12 carbon atoms. This perfluoroalkyl group may be linear or branched, and includes perfluorobutyl group, perfluorooctyl group, perfluoro-2-ethylhexyl group, perfluorodecyl group, perfluorododecyl group, Examples include perfluorotetradecyl group, perfluorohexadecyl group, and perfluorooctadecyl group. Although there is no particular restriction on the group that binds to this perfluoroalkyl group, it is believed that the silicone composition of the present invention to which this component (c) is added is of the addition reaction type using a platinum catalyst as described above. Therefore, it is preferable that this bonding group is an organic group that does not contain nitrogen, sulfur, phosphorus, etc. that poison the platinum catalyst. Therefore, this organic group may generally be a hydrocarbon group, including alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and amyl groups, phenyl groups, and biphenyl groups. Examples include unsaturated hydrocarbon groups such as aryl groups, vinyl groups, and allyl groups;
This organic group may be modified with silane or siloxane in order to improve the compatibility with the organosiloxane as component (a) and component (b). In addition to being able to achieve even easier peeling, it is also advantageous in that it is possible to prevent a decrease in residual adhesiveness and a decrease in peelability due to changes over time. The composition of the present invention is made by blending the above-described components (a) to (d), and the blending ratio of these components (a) and (b) is (a) If the molar ratio between the ≡SiH bond in the component and the aliphatic unsaturated hydrocarbon group in the component (b) is 0.2 or less or 20 or more, the silicone component that does not participate in these addition reactions becomes excessive and hinders the curing reaction. Therefore, it is best to keep the molar ratio in the range of 0.2 to 20, and the amount of component (c) should be 0.01% or less based on the total amount of components (a) and (b). If it is more than 10%, the residual adhesion of this cured film will deteriorate, so this should be 0.01 to 10%, preferably 0.01 to 10%, based on the total amount of components (a) and (b). 0.1~5%
And it is sufficient. The amount of the platinum-based catalyst as component (d) may be within the known range, and this is within the range mentioned above.
If the amount of Pt is less than 0.001% of the total amount of components (a) and (b), the catalytic effect will be insufficient, and adding more than 0.1% will only increase the cost. The amount may be 0.001 to 0.1%. The composition of the present invention is usually applied to a substrate in a diluted form with an organic solvent such as toluene, xylene, trichloroethylene, perchloroethylene, hexane, ethyl acetate, or methyl ethyl ketone, but the From the viewpoint of adhesion to the material and prevention of repelling, the viscosity of the treatment bath liquid when diluting components (a) and (b) with the organic solvent is 5 to 100,000 cS at 25°C, preferably 10 to 10,000 cS.
The organic group bonded to the perfluoroalkyl group constituting component (c) is preferably lipophilic. The composition of the present invention thus produced is coated onto a substrate such as paper, various processed papers, or plastic film using a known coating method such as a roll coater, gravure coater, or air coater. , then at 100℃ or higher, preferably 120℃ or higher.
A cured film with mold release properties is formed on the substrate by heat treatment for 10 seconds or more, preferably 20 seconds or more, and the above-mentioned component (c) is added to this composition. This improves the wettability to the substrate, and the leveling effect during coating provides a uniform coating film, so even if the coating amount is around 0.3g/ ^m2 , the uncoated This has the advantage that there is no risk of increasing the coating area and therefore the amount of coating can be significantly reduced compared to conventional methods, which also reduces the residual adhesion of the cured film. Therefore, it is considered to be industrially useful as a silicone composition with excellent mold release properties. In addition, in the composition of the present invention, a diorganopolysiloxane such as dimethylpolysiloxane may be added to the above-mentioned components (a) to (d) for the purpose of making the composition easy to peel. For the purpose of suppressing the activity of the platinum-based catalyst as a component, various known activity suppressors, such as organic nitrogen compounds, organic phosphorus compounds, sulfur-containing compounds, acetylene compounds, etc., are used within a very small amount that does not poison the catalyst. It may be added with Next, examples of the present invention will be given, in which parts are parts by weight, and viscosity is a value measured at 25°C. Example 1, Comparative Example 1 Methylhydrodiene polysiloxane with a viscosity of 25 cS and whose terminals were blocked with trimethylsilyl groups [(a)
component] and 1.0 mol% of the total organic groups are vinyl groups,
Viscosity is 12000cS when diluted to 30% with toluene
A methylvinylpolysiloxane [component b] whose terminal end is capped with a dimethylvinylsilyl group is combined with the ≡SiH bond of the component (a) and the ≡Si-CH= of the component (b).
Mix at a compounding ratio such that the molar ratio with CH ₂ group is 1.0, and per 100 parts of this mixture, 0.5 part of perfluorooctylethylene (C ₈ F ₁₇ CH=CH ₂ ) [component (c)] and platinum chloride. Complex of acid and vinyl siloxane (Pt
2% concentration) [component (d)] (2.0 parts) was added, and this was diluted with toluene to prepare a treatment liquid with a silicone content of 5%. Next, this treatment solution was applied to high-quality paper laminated with polyethylene using a wire parser of various counts so that the amount of silicone applied was as shown in Table 1, and a hot air circulation method was applied at 150°C. in the dryer
Heat treatment was performed for 20 seconds, and the silicone-treated paper thus obtained was allowed to stand at room temperature for one day.
Co., Ltd., trade name] to a solid content of 50 g/m ² , dried at 100°C for 3 minutes, bonded to high-quality surface paper, and crimped once with a 2 kg rubber roll. A test piece for measuring peeling force was prepared by leaving it to stand for one day, and the peeling force was measured using an autograph at a peeling angle of 180° and a peeling speed of 0.3 m/min. The results are shown in Table 1. Similar results were obtained. In addition, for comparison, we measured the peel force of a test piece obtained in the same manner as above except that perfluorooctylethylene as component (c) was not added, and this is also listed in Table 1. The results were as follows.

[Table] In other words, when perfluorooctylethylene is added as component (c), the peeling force does not suddenly increase even if the silicone coating amount becomes 0.4 g/ ^m2 , whereas in the comparative example At 0.4 g/m ² , this tendency was already noticeable. In addition, no significant difference was observed between Example 1 and Comparative Example 1 in the curability, residual adhesiveness, and other physical properties of this composition. Examples 2 and 3 Perfluorooctylethylene and trimethoxysilane are reacted using a heat-treated product of chloroplatinic acid and butyl alcohol as a catalyst to produce 1-perfluorooctyl-2-trimethoxysilylethane [hereinafter (c )-2], and further this (c)-2
The cyclic body obtained by hydrolyzing was reacted with octamethylcyclotetrasiloxane and hexamethyldisiloxane using trifluoroacetic acid as a catalyst to produce a compound represented by the following formula [hereinafter abbreviated as (c)-3]. . Next, in place of perfluorooctylethylene in Example 1, (c)-2 and (c)-3 obtained above were used.
was added to components (a), (b), and (d) in Example 1 to make a silicone composition, which was treated in the same manner as in Example 1 to create a test piece for peel force measurement. When the peeling force was measured, the results shown in Table 2 below were obtained.

[Table] Examples 4 to 7, Comparative Example 2 Methylhydrodiene polysiloxane [component (a)] having a viscosity of 90 cS and containing 60 mol% of methylhydrodiene siloxane units whose terminals are capped with dimethylhydrodienesilyl groups , total organic groups
2.0 mol% of the total organic groups are vinyl groups, and the viscosity is 6000 cS when diluted to 30% with toluene. Methylvinyl polysiloxane is terminal-capped with dimethylvinylsilyl groups, and 0.5 mol% of the total organic groups are vinyl groups. A mixture of equal amounts of methylvinylpolysiloxane terminal-capped with dimethylvinylsilyl groups [component (b)], which has a viscosity of 3000cS when diluted to 30% with toluene, is added to the ≡ in component (a). A perfluoroalkyl _group -containing compound [(c) Component] was added in the amount shown in the same table, and to this was further added 3.0 parts of a complex compound of chloroplatinic acid and vinylsiloxane (Pt concentration 1.0%), and these were diluted with toluene to give a silicone content of 5%. A processing solution was prepared, and for comparison, a processing solution containing the same formulation except that this perfluoroalkyl group-containing compound was not added was also prepared. Next, using these treatment solutions, silicone-treated paper and a test piece for measuring peeling force were made using the same in the same manner as in Example 1, and a peeling force test was conducted on the paper, as shown in Table 4. The results shown were obtained.

【table】

[Table] When examining the changes in residual adhesive strength (%) and peeling force over time for the above-mentioned Examples 6 and 7, the results shown in Table 5 below were obtained. It was confirmed that the product in which the organic group bonded to the perfluoroalkyl group was modified with siloxane (Example 6) was superior to the product without this modification (Example 7).

【table】

Claims (1)

[Claims] 1 (a) Unit formula [Formula] in the molecular chain (where R ¹ is an unsubstituted or substituted monovalent saturated hydrocarbon group, a and b are both 1
Organohydrodiene polysiloxane (b) having a siloxane unit represented by the above integer a+b≦3) In the molecular chain, the unit formula [formula] (where R ² is a monovalent aliphatic unsaturated hydrocarbon group, R ³ is an unsubstituted or substituted monovalent saturated hydrocarbon group, c and d are both integers of 1 or more, and an aliphatic unsaturated hydrocarbon group-containing organopolysiloxane (c) having a siloxane unit represented by c+d≦3) 1. A silicone composition for mold release, comprising: (d) one or more compounds having a perfluoroalkyl group having 4 to 20 carbon atoms; and (d) one or more platinum or platinum compounds.