JP2915778B2 - Silicone composition for release paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be applied to the surface of a silicone composition for release paper, especially paper, laminated paper, plastic film, metal foil or the like without containing an organic solvent. While making it sticky,
The present invention relates to a release paper silicone composition which can impart excellent release properties and slipperiness.

[0002]

2. Description of the Related Art In order to prevent sticking or sticking between a substrate such as paper and plastic film and an adhesive substance, or between paper and paper, between paper and plastic film, between plastic films, between paper or plastic film and human. With respect to the release silicone composition used for imparting slipperiness between the hands, various types of organopolysiloxane solutions in organic solvents and aqueous emulsions have been proposed (Japanese Patent Publication No. No. 13,709, Tokiko Sho 36
-1,397, JP-B-46-26,798).

However, this type of organic solvent includes:
Various proposals have been made regarding the siloxane composition, additives, co-catalysts, etc. in order to obtain excellent release properties, slip properties, abrasion resistance, curing properties, etc. Since siloxane is of a rubbery high molecular weight, its use requires a large amount of organic solvent and therefore has the disadvantage of causing air pollution, and the recovery of this solvent is expensive. There is a problem that.

Although the above-mentioned problems due to the use of an organic solvent do not occur in this aqueous emulsion type, high-temperature and long-time heating is required to prevent secondary pollution due to the use of an emulsifier and to form a film. It is necessary, and since it is difficult to use a high molecular weight organopolysiloxane as a main agent, it has excellent physical properties and has a drawback that a slippery film cannot be formed.

[0005]

Therefore, a solvent-free composition containing no organic solvent or water has been proposed for the release paper silicone composition (Japanese Patent Publication No. Sho 52-182).
No. 47,485), however, because polyvinyl siloxane used as a base material thereof has a low molecular weight, a film obtained from this composition has poor physical properties such as mechanical strength and slip property. However, there is a disadvantage that the use is limited and its use is limited.

As for this solvent-free silicone release agent, it has been attempted to add a slipperiness imparting agent such as a polyether-modified oil, a surfactant, a wax, or a metallic soap to dimethylsiloxane oil. Most of them are poorly compatible with silicone and tend to separate or cause poor curing.In addition, since these bleed out on the cured silicone film, they were made using these. When a pressure-sensitive adhesive product is manufactured using a release paper, there is a problem that the product is transferred to the surface of the pressure-sensitive adhesive and the adhesive strength is reduced.

[0007] A method of adding a high-molecular-weight organopolysiloxane having a hydroxyl group bonded to a silicon atom at the molecular chain end of the solvent-free silicone release agent is also known (Japanese Patent Publication No. 3-19,268). However, although this has improved slipperiness and other properties, it has a problem that it is difficult to use it for coating at high speed because of its viscosity limitation.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a silicone composition for release paper which overcomes these disadvantages, drawbacks and problems, including: 1) bonding to at least two silicon atoms in the molecule; Having a vinyl group content of 0.5 to 10.0 mol% and a viscosity at 25 ° C. of 50 to 50 mol%.
~ 10,000 cps, 100 to 50 parts by weight of a linear or branched organopolysiloxane in which both ends of the molecular chain are blocked with a trialkylsilyl group, and at least two silicon atoms in the molecule. It has a vinyl group, the amount of the vinyl group is 0.5 to 10.0 mol%, and the viscosity at 25 ° C. is 50 to 10,000.
100 cps, 100 parts by weight of a mixture with 0 to 50 parts by weight of a linear or branched organopolysiloxane in which both terminals of the molecular chain are blocked with a triorganosilyl group, 2) at least a silicon atom in one molecule Wherein the structural unit is (CH ₃ ) _a H _b SiO _{(4-ab) / 2} (where a is an integer of 0 to 3, b is 0 or 1, and 1 ≦ a + b ≦ 3) 0.5 to 40 parts by weight of methyl hydrogen polysiloxane represented by 3)
A catalytic amount of a platinum compound, which is substantially free of an organic solvent and has a viscosity at 25 ° C. of 50 to 10,000 cps.

That is, the present inventors have conducted various studies to develop a solvent-free silicone composition for release paper that can impart excellent release properties and slipperiness to paper, plastic films, and the like. The vinyl group-containing polysiloxane and the methyl hydrogen polysiloxane are of an addition reaction type using a platinum compound as a catalyst, and the vinyl group-containing polysiloxane is of a low polymerization degree having no vinyl group at the molecular chain terminal. Then, in the network formed by the reaction between the vinyl group-containing polysiloxane and the methyl hydrogen polysiloxane, comb-like polysiloxy groups rise, and have excellent slipperiness and mechanical properties, and have a releasability with less bleed-out material. Research on the types and amounts of these components. Advanced has led to the completion of the present invention. This is described in more detail below.

[0010]

The present invention relates to a silicone composition for release paper, which cures a vinyl group-containing polysiloxane and methyl hydrogen polysiloxane by an addition reaction in the presence of a platinum compound catalyst. Assuming that the vinyl group-containing polysiloxane has a viscosity at 25 ° C. of 50 to 10,000 cps substantially free of an organic solvent mainly containing a vinyl group that is not present at a molecular chain terminal and having a viscosity of 50 to 10,000 cps. The addition of the vinyl group-containing polysiloxane and the methyl hydrogen polysiloxane provides the advantage of providing a film having excellent sliding properties and mechanical properties, a small amount of bleed-out substances, and excellent mold release properties.

The organopolysiloxane as the first component constituting the silicone composition for release paper of the present invention has a vinyl group bonded to at least two silicon atoms in one molecule. It is necessary that a vinyl group is not present at the terminal of a molecular chain as a main component, and it may be a compound obtained by adding an organopolysiloxane having at least one vinyl group at a terminal of a molecular chain as a subcomponent.

As the main component, the vinyl group-containing polysiloxane is a linear or branched one having at least two vinyl groups bonded to a silicon atom in the molecule. )

Embedded image Wherein R ¹ is an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, R ² is the same alkyl group as R ¹ , or an aryl group such as a phenyl group or a tolyl group, or a cycloalkyl group such as a cyclohexyl group Same or different selected from chloromethyl group, trifluoropropyl group, cyanoethyl group, etc., in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups or these groups are substituted with halogen atoms, cyano groups, etc. Unsubstituted or substituted 1
A valent hydrocarbon group, and

Embedded image (Where L is an integer), and for practical purposes, R ¹ and R ² are those in which 80 mol% are methyl groups, and m and n are integers of m ≧ 8 and n ≧ 2. It is assumed that the molecular chain end is blocked with a trialkylsilyl group.

The vinyl group-containing polysiloxane as an auxiliary component is also a linear or branched one having at least two vinyl groups bonded to silicon atoms in the molecule. (2)

Embedded image Wherein R ¹ and R ² are the same as above, a is an integer of 1 to 3, p and q are integers of p ≧ 10 and q ≧ 0, which are represented by the formula As described above, the molecular chain ends may be blocked with, for example, a dimethylvinylsilyl group.

Each of the main or sub-component vinyl group-containing polysiloxanes has a vinyl group content of all organic groups.
If it is less than 0.5 mol%, its curability will be poor,
If it exceeds mol%, the peeling resistance of the cured film obtained from this composition increases, and the adhesion to the pressure-sensitive adhesive becomes unstable in practical use. Required, preferably 1.0 to 8.0 mol%
It is good to be. In addition, since these are required to have a low degree of polymerization from the viewpoint of coatability, they are necessarily of low viscosity, but it is not practically preferable to use 10,000 cps or more. Therefore, it is necessary that the viscosity at 25 ° C. is in the range of 50 to 10,000 cps, and the preferable range is 100 to 5,000 cps.

The mixing ratio between the main component and the sub component is
Since the characteristics of the silicone composition of the present invention due to the use of the main component decrease as the mixing ratio of the sub-component increases, the amount of the sub-component is 0 to 100 to 50 parts by weight of the main component.
It is required to be in the range of 50 parts by weight.

Next, the methylhydrogenpolysiloxane as the second component constituting the release paper silicone composition may be a known one used in this kind of addition-reaction silicone composition, and it may comprise one molecule. It contains at least two, preferably two or more hydrogen atoms bonded to silicon atoms. Examples of this type of polysiloxane include (CH ₃ ) HSiO units, HSiO _3/2 units, (CH ₃ ) ₂ SiO units, and (C
Examples include polymers or copolymers consisting of H ₃ ) ₂ HSiO _1/2 units, CH ₃ SiO _3/2 units, and (CH ₃ ) ₃ SiO _1/2 units, which may be linear or cyclic. The viscosity at 25 ° C. may be 10 to 500 cps, but the blending amount may be in accordance with the amount of vinyl groups contained in the first component. From the viewpoint of the peeling performance, the amount may be in the range of 0.5 to 40 parts by weight with respect to 100 parts by weight of the first component.

Further, the platinum compound as the third component constituting the silicone composition for release paper of the present invention is used as a catalyst for carrying out an addition reaction between the above-mentioned first and second components. This may be a known catalyst of this type, and examples thereof include chloroplatinic acid, alcohol solutions of chloroplatinic acid, aldehyde solutions, complex salts of chloroplatinic acid with olefins, and vinylsiloxanes. You. The addition amount may be the catalyst amount, but in order to obtain a good cured film and from the economical viewpoint, the platinum amount may be in the range of 1 to 1,000 ppm based on 100 parts by weight of the first component.

The silicone composition for release paper of the present invention can be obtained by blending a predetermined amount of the above-mentioned first to third components. This is accomplished by mixing the first and second components uniformly beforehand. It is preferred to add a third component. In addition,
For the purpose of suppressing the activity of the platinum catalyst as the third component, an activity inhibitor such as an organic nitrogen compound, an organic phosphorus compound, an acetylene compound, an oxime compound, or an organic chloro compound is added as necessary. Is also good.

Although the silicone composition for release paper of the present invention thus obtained does not contain an organic solvent,
From the viewpoint of coatability, the viscosity at 25 ° C. is preferably in the range of 50 to 10,000 cps, and the specific viscosity value may be determined according to the type of the coating substrate used here.
For example, this coated base material is polyethylene laminated paper, OP
P film, aluminum foil, etc., and when it is applied with a known technology such as a roll coater, a gravure coater, an air coater, a curtain flow coater, and an offset transfer rotor at an application amount of 0.3 to 3 g / m ² , Low viscosity, such as 50 to 10,000 cps, and higher viscosity for highly permeable substrates such as glassine paper, kraft paper, clay-coated paper, etc. Is good.

The substrate treated with the silicone composition for release paper of the present invention may be heated at a temperature of 80 to 200 ° C. for 5 to 6 seconds or may be irradiated with an ultraviolet ray from a UV irradiator such as 80 w / cm. Is irradiated for 0.2 seconds or more, a cured film is formed on the surface, and the cured film has the advantage of exhibiting slipperiness and excellent releasability.

[0021]

EXAMPLES Examples of the present invention and comparative examples will now be described.
The parts in the examples are parts by weight, and the viscosities are values measured at 25 ° C., and the physical properties in the examples are values measured by the following methods. (Curability) After applying a predetermined amount of the composition to the surface of a thin film or sheet-like substrate, the composition is heated for a predetermined time in a hot air circulation dryer at a predetermined temperature, and the obtained cured film is rubbed with a finger. Detachment and clouding of the film are determined.

(Peeling Resistance) A predetermined amount of the composition is applied to the surface of a thin film or sheet substrate and heated for a predetermined time in a hot air circulating drier at a predetermined temperature. , Acrylic solvent-type adhesive, Olivain BPS-
5127 [trade name of Toyo Ink Mfg. Co., Ltd.] or acrylic emulsion-type pressure-sensitive adhesive, Olivain BPW-3110H
[Company name] is applied and heat-treated at 100 ° C for 3 minutes. Then, high-quality paper with a basis weight of 64 g / cm ² is attached to the treated surface,
It is pressed and reciprocated once with a 2 kg roller, aged at 25 ° C for a predetermined time, cut into 5 cm widths to form test specimens, and peeled at a 180 ° angle using a tensile tester at a speed of 0.3 m / min.
The laminated paper is pulled at m / min, and the force (g) required for peeling is measured.

(Slipperiness) After forming a cured film of the composition on the surface of the sheet-like substrate by the same method as the peel resistance test,
A urethane rubber or styrene-butadiene rubber with a load of 200 g is placed on the surface and pulled in a direction parallel to the surface of the cured silicone film at a rate of 0.3 m / min, and the required force (g) is measured. The required force / 200 is calculated as the dynamic friction coefficient (according to ASTM D1894-63). As for the slip property, the relative slip property was determined by moving a hand over the surface of the cured film, and the slip property was determined according to the following criteria. ◎… Slip very well 〇… Slip good ×…
Not slippery ×× ... Not slippery

(Residual Adhesion Rate) After forming a cured film of the composition on the surface of the sheet-like substrate by the same method as the peel resistance test, a polyester tape Lumirror 31B [trade name of Nitto Denko Corporation] is formed on the surface. And heat-treated at 70 ° C for 20 hours under a load of 20 g / cm ² , then peel off the tape and paste it on a stainless steel plate. Then, peel the tape at an angle of 180 ° and peeling speed of 0.3 m / min. And the force (g) required for the peeling is measured, and expressed as a percentage of the force (g) required for peeling the untreated standard tape.

Examples 1-2, Comparative Examples 1-2 Both ends of the molecular chain were blocked with a trimethylsilyl group,
Polysiloxane has four vinyl groups bonded to its side chain. The vinyl group content is 1.2 mol% and the viscosity is 600 cps.
100 parts of a copolymer of dimethylsiloxane and methylvinylsiloxane is blocked with trimethylsilyl groups at both ends of the molecular chain, containing 70 mol% methylhydrogensiloxy units in the molecule and having a viscosity of 50 cps. 3 parts of a certain methyl hydrogen polysiloxane and formula

Embedded image After adding 1 part of 3-methyl-1-butyn-3-ol represented by the formula (1) and uniformly stirring and mixing, 2 parts of a complex salt of chloroplatinic acid and vinylsiloxane (200 ppm in terms of platinum) is added thereto, and silicone is added. Composition A was made.

For comparison, instead of the above-mentioned copolymer of dimethylsiloxane and vinylsiloxane, both ends of the molecular chain are blocked with dimethylvinylsilyl groups, and two vinyl groups are added to the side chain of the polysiloxane. Group is linked, vinyl group content is 1.2mol%, viscosity is 600cps
A silicone composition B was prepared in the same manner as in the example except that a copolymer of dimethylsiloxane and methylvinylsiloxane was used.

Next, the silicone compositions A and B are
A silicone composition C was prepared by mixing at 60:40, and 5 parts of dimethyl silicone oil having a viscosity of 1,000 cps was added to the silicone composition B to prepare a silicone composition D. The curability of the silicone compositions A to D was determined. The peel resistance, slipperiness, and residual adhesion of the cured film formed from the cured film were examined. The results shown in Tables 1 and 2 were obtained. The curability shows the measurement results of those obtained by applying these compositions to polyethylene laminated paper at 0.7 g / m ² and treating them at 140 ° C. for 20 seconds. Comparative Example 1 had satisfactory curability, peel resistance, slipperiness, and residual adhesiveness.
Is poor in slipperiness, and that of Comparative Example 2 is slippery,
The hand was good, but it was confirmed that the residual adhesion rate was poor.

[0028]

[Table 1]

[Table 2]

[0029]

The present invention relates to a silicone composition for release paper, which is represented by the general formula (1) to which a vinyl group-containing polysiloxane represented by the general formula (2) is added as required. The vinyl group-containing polysiloxane shown does not contain an organic solvent composed of methyl hydrogen polysiloxane and a platinum compound catalyst, and has a viscosity of 50.
~ 10,000cps, which has the general formula (1)
Since the polysiloxane represented by does not have a vinyl group at the molecular chain end, the cured film has excellent slipperiness and mechanical properties, has less bleed-out substances, and has excellent mold release properties. Gives the advantage of becoming

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09D 183/07 C08L 83/05 C08L 83/07 C09D 183/05 C09J 7/02

Claims (1)

(57) [Claims] (1) A molecule having a vinyl group bonded to at least two silicon atoms in a side chain in a molecule, the amount of the vinyl group is 0.5 to 10.0 mol% of all organic groups, and the viscosity at 25 ° C. Is 50
~ 10,000 cps, 100 to 50 parts by weight of a linear or branched organopolysiloxane in which both ends of the molecular chain are blocked with a trialkylsilyl group, and at least two silicon atoms in the molecule. It has a vinyl group, the vinyl group content is 0.5 to 10.0 mol% of the total organic group, the viscosity at 25 ° C is 50 to 10,000 cps, and both ends of the molecular chain are blocked with a triorganosilyl group. 100 parts by weight of a mixture of 0 to 50 parts by weight of a branched or branched organopolysiloxane, 2) having at least two hydrogen atoms bonded to at least two silicon atoms in one molecule, and having a structural unit of (CH ₃ ) _{a H b SiO (4-ab} ) / 2 ( here a is an integer of 0 to 3, b is 1 ≦ a + b ≦ 0 or 1
Methyl hydrogen polysiloxane represented by 3)
0.5 to 40 parts by weight, 3) a catalytic amount of a platinum compound, substantially free of an organic solvent, having a viscosity at 25 ° C. of 50 to 10,000 cps. Stuff.