JPH0660298B2 - Silicone composition for coating - Google Patents

Description

TECHNICAL FIELD The present invention relates to a silicone composition for coating, and more particularly to a coating composition having an antistatic effect as well as releasability and lubricity.

<Prior art> A material such as paper or film coated with curable silicone tends to be charged with static electricity. Especially, films such as polyester and oriented polypropylene (OPP) are easily charged by friction, so that the coated surface is Dust adheres and the films block each other, which is an obstacle to handling, and causes troubles such as noise when the cured film is applied to electric parts.

Conventionally, in order to prevent these drawbacks, an undercoat layer having an antistatic property may be provided before applying silicone,
The same process had to be performed on the back side.
As such a treatment, for example, a method using a partial hydrolyzate of polysiloxane (JP-A-60-141553) is used.
No.), a method of applying a surfactant, and a method of applying a resin layer mixed with a conductive powder such as metal or carbon (Jitsuko Sho 62-18448).

<< Problems to be Solved by the Invention >> However, in order to obtain a silicone coating having antistatic properties by these methods, it is necessary to perform coating twice, which is disadvantageous in terms of productivity and cost. The provision of these undercoat layers has a drawback that the curability and adhesion of silicone are impaired.

The inventors of the present invention have conducted extensive studies to solve the above-mentioned drawbacks, and as a result, a known curing method comprising a terminal hydroxy group-containing organopolysiloxane, an organohydrogenpolysiloxane or an organoalkoxypolysiloxane, and a catalyst for condensation reaction. When a long-chain alkyl group-containing quaternary ammonium salt is used as an additive in a water-soluble organopolysiloxane composition, good results can be obtained by a single coating without undercoating or backside treatment. Heading, arrived at the present invention.

Therefore, an object of the present invention is to provide a silicone composition for coating, which is capable of imparting releasability and lubricity as well as an antistatic effect by a single application.

<< Means for Solving the Problems >> The above objects of the present invention are as follows: (1) Organopolysiloxane having hydroxyl groups bonded to silicon atoms at both ends of the molecular chain: 100 parts by weight (2) Silicon in one molecule At least one organohydrogenpolysiloxane having at least three hydrogen atoms bonded to elementary atoms and at least one organoalkoxypolysiloxane having at least three alkoxy groups in the silicon atom in one molecule. Polysiloxane: 1 to 100 parts by weight (3) Long chain alkyl group-containing quaternary ammonium salt 1 to 30 parts by weight (4) Condensation reaction catalyst: 0.5 to 50 parts by weight and (5)
Achieved by a coating silicone composition containing a volatile solvent.

The organopolysiloxane as the first component constituting the composition of the present invention has the general formula Which has a hydroxyl group bonded to a silicon atom at both ends of the molecular chain, and a substantially linear one is preferable. The organic groups R ¹ and R ² bonded to the silicon atom in the above general formula include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an aryl group such as a phenyl group and a tolyl group, a cyclopentyl group. Same or different unsubstituted or substituted monovalent group in which a part or all of the hydrogen atoms bonded to the carbon atoms of these groups, such as cycloalkyl groups and cyclohexyl groups, are substituted with halogen atoms, cyano groups, etc. Although a hydrocarbon group can be mentioned, it is preferable that 80 mol% or more of this organic group is a methyl group from the viewpoint of releasing property.

Further, n in the general formula is a number of 100 or more. n is 10
If it is less than 0, a repelling phenomenon occurs and the coatability becomes poor.

Next, the organohydrogenpolysiloxane and organoalkoxypolysiloxane as the second component constituting the silicone composition of the present invention are appropriately selected from those used in known condensation reaction type silicone compositions and used. be able to. Specifically, it is necessary to have at least three hydrogen atoms (≡SiH groups) or alkoxy groups bonded to a silicon atom in one molecule, but the other organic group has 60 moles thereof. % Or more is preferably a methyl group. This type of organohydrogenpolysiloxane has an average unit formula [Wherein R ³ is an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and amylhexyl; a cycloalkyl group such as cyclopentyl and cyclohexyl; an aryl group such as phenyl and naphthyl; tolyl, xylyl, ethylphenyl, mesityl An alkaryl group such as; a monovalent hydrocarbon group selected from aralkyl groups such as benzyl and phenylethyl; a is 0 ≦ a <3
, B is a number 0 <b ≦ 3, and 1.5 ≦ a + b ≦
It is 3. ] It is especially preferable that 80 mol% or more of R ³ is a methyl group from the viewpoint of compatibility and curability. Specifically, (CH ₃ ) HSiO unit, HSiO _1.5 unit, (CH ₃ ) ₂ SiO unit, CH ₃ S
Examples thereof include homopolymers or copolymers composed of iO _1.5 units, (CH ₃ ) ₂ HSiO _0.5 units, or (CH ₃ ) ₃ SiO _1.5 units, which may be linear, branched or cyclic. Good, viscosity at 25 ℃ is 10-50
The range of 0 cs is preferable.

Organoalkoxypolysiloxanes have the following average unit formula (II) [Wherein R ⁴ is an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl and amylhexyl; a cycloalkyl group such as cyclopentyl and cyclohexyl; an aryl group such as phenyl and naphthyl; tolyl, xylyl, ethylphenyl and mesityl; An alkaryl group such as; a monovalent hydrocarbon group selected from aralkyl groups such as benzyl and phenylethyl; R ⁵ is methyl;
An alkyl group such as ethyl, propyl, isopropyl, butyl, isobutyl, amyl and hexyl group; c is 0
≦ a <3, d is 0 <d ≦ 3, and 1 ≦ c +
d ≦ 3. ] And has at least 3 R ⁵ O groups in the molecule. The viscosity of this organoalkoxypolysiloxane is about 1-2 at 25 ° C.
It is preferably 0 cs.

Such an organoalkoxypolysiloxane can be produced by condensing an alkoxysilane mixture containing trialkoxysilane as a main component and, if necessary, dialkoxysilane, according to a known method.
Examples of the trialkoxysilane used here include CH ₃ Si (OCH ₃ ) ₃ , CH ₃ Si (OC ₂ H ₅ ) ₃ , C ₂ H ₅ Si (OCH ₃ ) ₃ , nC ₃ H ₇ Si ( _{OCH 3) 3, iso-C} 3 H 7 Si (OCH 3) 3, nC 4 H 9 Si (OCH 3) 3, iso-C 4 H 9 Si (OCH 3) 3, There are equal, and as the dialkoxysilane, for _{example, (CH 3) 2 Si (} OCH 3) 2, (CH 3) 2 Si (OC 2 H 5) 2, CH 3 (C 2 H 5) Si (OCH ₃ ) ₂ , (C ₂ H ₅ ) ₂ Si (OCH ₃ ) ₂ , Etc.

The organohydrogenpolysiloxane and the organoalkoxypolysiloxane which are the second components may be used alone or in combination of two or more kinds.

The compounding amount of the second component in the composition of the present invention is 1 to 100 parts by weight, preferably 5 to 50 parts by weight, relative to 100 parts by weight of the first component. If the compounding amount of the second component is less than 1 part by weight, curing will be poor and cause back migration to the silicone content. If it exceeds 100 parts by weight, properties such as slipperiness and peelability of the cured film will be adversely affected. .

The long-chain alkyl group-containing quaternary ammonium salt used as the third component in the composition of the present invention has, for example, the following chemical formula (III): [In the formula, R ⁶ represents an alkyl group having 10 to 18 carbon atoms, R ⁷
Is methyl, ethyl, propyl, isopropyl, butyl,
An alkyl group having 1 to 18 carbon atoms such as isobutyl, amyl and hexyl; a cycloalkyl group such as cyclopentyl and cyclohexyl; an aryl group such as phenyl and naphthyl; an alkaryl group such as tolyl, xylyl, ethylphenyl and mesityl; benzyl, A monovalent hydrocarbon group such as an aralkyl group appropriately selected from phenylethyl and the like]. These ammonium salts may be used alone or in combination of two or more.

The blending amount of the third component is about 1 to 30 parts by weight, preferably about 2 to 20 parts by weight, based on 100 parts by weight of the first component.

When the content of the third component is less than 1 part by weight, the effect of imparting antistatic property to the cured film formed from this composition is poor, and when it exceeds 30 parts by weight, the curability of the film is impaired and the silicone content is reduced. The physical property of the film is impaired by the migration to the back surface. In the range of 1 to 30 parts by weight, the antistatic property is controlled according to the addition amount, and the surface resistance value is 10 ⁶ to 10 ¹³
It can be Ω.

The condensation reaction catalyst, which is the fourth component in the composition of the present invention, is used for condensing the first component and the second component, and may be appropriately selected and used from known ones. it can. Examples of such a catalyst include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, tin oleate, tin stearate, zinc palmitate, and zinc octylate. The amount of the catalyst used varies depending on the curing conditions, the type of the treated substrate, etc., but is generally 0.5 to 50 parts by weight, preferably 1 to 20 parts by weight, relative to 100 parts by weight of the first component.

Examples of the volatile solvent which is the fifth component in the composition of the present invention include toluene, hexane, heptane, ethyl acetate, methyl ethyl ketone and the like. These volatile solvents may be used in the first, second, and third types according to the coating conditions.
It may be added in an appropriate ratio with respect to the fourth component and usually 100 to 10,000 parts by weight per 100 parts by weight of the first component.

The composition of the present invention is obtained by appropriately blending the first, second, third, fourth and fifth components, but the blending is such that the first, second, third and fifth components are homogeneous in advance. It is preferred to add the fourth component after use after mixing with the above.

The viscosity when using the composition of the present invention thus obtained, coating amount and coating method and the coating substrate to be treated,
For example, it may be determined depending on the type of polyester, polypropylene, vinyl chloride, etc., but from the viewpoint of workability during coating, it is preferable that the viscosity at 25 ° C. be approximately 1,000 cps or less.

In forming the film, a known technique such as a roll coater can be used. The film thickness after curing is 0.
It is preferably about 05 to 2 μm.

The substrate coated with the composition of the present invention is heat-treated at 80 ° C. or higher, preferably 100 ° C. or higher for 15 seconds or longer to form a film having a surface resistance value of 10 ¹³ Ω or less and releasability on the surface thereof. can do. This cured film has excellent adhesiveness to plastics and the like, and also has excellent abrasion resistance, so that it is suitable for application in medical tack paper, cassette tape free-cut sheets, and other fields related to the electronics industry.

<< Effects of the Invention >> By directly applying the composition of the present invention to an easily charged object such as a plastic film without providing a charge-treated layer in advance, it is possible to obtain a good release property on the coated object in one step. Moldability, lubricity and antistatic ability can be imparted.

<< Example >> Next, an example of the present invention will be described, but the present invention is not limited thereto. The parts in the examples are parts by weight,
The viscosity is a value measured at 25 ° C.

In addition, the measuring method of each physical property in an Example is as follows.

[Curability]

After applying a predetermined amount of the composition to the surface of a thin film or sheet-shaped substrate, heating for a predetermined time in a hot air circulation dryer at a predetermined temperature until a complete cured film is formed (seconds) Was measured.

In this case, the determination of the time of curing was made at the time when the coated surface did not fall off even if the obtained coated surface was lightly rubbed with a finger and the coated surface did not become cloudy.

[Peeling force]

A predetermined amount of the composition is applied to the surface of a thin film or sheet-like substrate, and a cured film is formed by heating for a predetermined time in a hot air circulation dryer held at a predetermined temperature, and then the cured film surface Acrylic adhesive Olivine BPS-8170
Apply [Product name of Toyo Ink Mfg. Co., Ltd.] to 100
Heat treatment at ℃ for 3 minutes, then weigh 64g on this treated surface
/ A bonded paper m ² adhered, 2 to under a load of 20g / m ²
Aging for 5 hours at 5 ℃, cut into 5cm width to make a test piece, and pull the laminated paper at a peeling speed of 0.3m / min at an angle of 180 ° using a tensile tester, and the force required for peeling. (G) was measured.

[Adhesion]

A predetermined amount of the composition is applied to the surface of a thin film or sheet-shaped substrate, and the composition is heated at a predetermined temperature for a predetermined time using a hot air circulation dryer to form a cured film, and then at 25 ° C. and relative humidity. It was placed in a constant temperature and humidity room of 60%, and the coated surface was rubbed with a finger every predetermined time, and it was judged whether or not the coated surface fell off.

[Surface resistance]

A predetermined amount of the composition is applied to the surface of a thin film or sheet-shaped substrate, and the composition is heated at a predetermined temperature for a predetermined time using a hot air circulation dryer to form a cured film, and then at 25 ° C. and relative humidity. It measured according to ASTMD-4854T in a 65% atmosphere.

[Transition]

A predetermined amount of the composition is applied to the surface of a thin film or sheet-shaped substrate, and heat-treated at a predetermined temperature for a predetermined time using a hot air circulation dryer to form a cured film, and then 25 μm polyethylene terephthalate ( After wrapping the PET film on the surface of the film and holding it at a pressure of 10 kg / cm ² for 1 day,
Wide velcro was applied to the silicone contact surface of the ET film and the ink repellency was observed.

Examples 1-4, Comparative Example 1. 100 parts of dimethylpolysiloxane having hydroxyl groups at both ends and a degree of polymerization of 5.000, and polymethoxymethylsiloxane having a viscosity of 5 cs blocked at both ends with trimethylsilyl groups 20
(A methoxy group content of 45% by weight) was dissolved in 230 parts of toluene to prepare a composition A.

To 10 parts of composition A, tetradecyldimethylbenzylammonium chloride was added in an amount of 0.05, 0.3,
After adding 0.6 and 0.9 parts and further diluting by adding 50 parts of toluene, 0.2 parts of dibutyltin diacetate was added and sufficiently stirred to prepare treatment liquids I to IV. Further, the treatment liquid V was prepared in exactly the same manner except that the tetradecyldimethylbenzylammonium chloride was not added.

These treatment solutions were applied to a PET film of 50 μm using a # 10 wire bar and heated at 140 ° C. for 30 seconds. The amount of silicone applied was 0.3 g / m ² . The results of measuring the above-mentioned various properties of these cured films are shown in Table 1.

The results in Table 1 demonstrate that by increasing the amount of tetradecyldimethylbenzylammonium chloride added, the surface resistance can be lowered while the peeling properties and other effects are reduced.

Example 5. 90 parts of dimethylpolysiloxane having hydroxyl groups at both ends and a degree of polymerization of 8,000, 10 parts of dimethylpolysiloxane having a degree of polymerization of 5,000 and having both ends blocked with trimethylsilyl groups,
A composition B was prepared by dissolving 3 parts of methylhydrogen polysiloxane having 20 degree of polymerization and blocked with trimethylsilyl groups at both ends and 20 parts of dodecyldimethylethylbenzylammonium chloride in 210 parts of toluene.

The results obtained by diluting 10 parts of the composition B with 50 parts of toluene as the treatment liquid VI and forming a cured film in the same manner as in Example 1 and measuring various properties were also shown in Table 1.

Claims (5)

[Claims] 1. A general formula An organopolysiloxane in which both ends of the molecular chain are capped with a (diorgano) hydroxy group (provided that R ¹ and R ² are an alkyl group, an aryl group, a cycloalkyl group,
Alternatively, an unsubstituted or substituted monovalent hydrocarbon group in which a part or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom or a cyano group, and R ¹ and R ² are the same. Or n may be different.
It is a number of 0 or more. ): 100 parts by weight 2. Average unit formula Organohydrogenpolysiloxane having at least 3 hydrogen atoms bonded to a silicon atom represented by the formula (R ³ is an alkyl group, a cycloalkyl group, an aryl group, an alkaryl group or an aralkyl group. A monovalent hydrocarbon group selected from the group, a is a number 0 ≦ a <3, b
Is 0 <b ≦ 3), and the average unit formula Of at least one organopolysiloxane selected from organoalkoxypolysiloxanes having at least three alkoxy groups bonded to a silicon atom in one molecule (provided that R ⁴ is the same as R ³ above). R ⁵ is an alkyl group, c is a number of 0 ≦ c <3, d is a number of 0 <d ≦ 3, and 1 ≦ c + d ≦ 3): 1 to 100 parts by weight 3. A long-chain alkyl group-containing quaternary ammonium salt: 1 to 25 parts by weight 4. A catalyst for condensation reaction: 0.5 to 50 parts by weight, and 5. A coating silicone composition containing a volatile solvent.