JP2965231B2 - Silicone composition for release paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a silicone composition for release paper, in particular, it can be applied to the surface of paper, laminated paper, plastic film, etc. without containing an organic solvent. The present invention relates to a silicone composition for release paper capable of imparting non-adhesiveness to paper.

[0002]

2. Description of the Related Art Conventionally, various types of solvent-free silicone compositions for release have been known which are used to prevent sticking or sticking between a substrate such as paper and plastic and an adhesive substance. (JP-A-49-47426, JP-A-50-14
No. 1591, JP-B-52-39791 and JP-A-57-77395).

[0003] However, these materials have good adhesion to paper, laminated paper, etc., but when cured at low temperature to prevent shrinkage of plastic films, especially polyethylene terephthalate and polypropylene films, the adhesion becomes insufficient. In particular, when the cured silicone film is held in a humid condition, there is a drawback that the cured silicone film peels off when rubbed with a finger for about one day.

[0004]

Therefore, in order to improve the adhesion to a plastic film, this type of organosiloxane composition must be blended with a certain type of silane or siloxane to impart self-adhesion. (See JP-B-46-2187 and JP-B-52-9469), all of which are cured by a condensation reaction and require high temperature for curing. There is also known a composition in which this siloxane contains an epoxy group at its terminal or side chain and is cured by an addition reaction (JP-A-52-24258). JP-A-52-147657,
However, this was also unsatisfactory in the non-adhesiveness of the cured film. In order to improve the adhesiveness, there is a method in which the surface of the adherend is treated with a primer in advance. However, this increases the number of steps by one step, and is a negative factor in terms of working time, labor, and cost. Is not preferred.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a silicone composition for release paper which solves such disadvantages. 1) The average composition formula is represented by the following formula (1).

Embedded image (Where R ¹ is an alkenyl group, R ² , R ³ and R ⁴ are the same or different monovalent organic groups, e is 3 ≦ e ≦ 100, f is 10
And an organopolysiloxane having a viscosity at 25 ° C. of 50 to 10,000 cp.
999.9 parts by weight 2) The average composition formula is the following formula (2)

Embedded image (Where R ⁵ is an alkenyl group, R ⁶ is the same or different monovalent hydrocarbon group , a is a positive number of 1 to 3, p ≧ 0, q ≧ 1)
And 99.9 to 0.1 parts by weight of an organopolysiloxane having a viscosity at 25 ° C of 50 to 10,000 cp; 3) 1.0 to 100 parts by weight of an organohydrogenpolysiloxane; and 4) a catalytic amount of platinum or a platinum-based compound. It is characterized by the following.

That is, the present inventors have conducted various studies on a solvent-free type silicone composition for releasing, which gives excellent release properties to paper, plastic films and the like. As a result, the organopolysiloxane containing an alkenyl group, which is the main component, has been studied. Assuming that the siloxane is represented by the above formulas (1) and (2) and a composition obtained by blending the organohydrogenpolysiloxane and the platinum-based catalyst with the siloxane,
A cured film is easily formed on the surface of the object to be treated by a heat treatment at a temperature of 70 to 200 ° C. for 1 to 30 seconds, and the cured film thus obtained has good adhesion to a substrate, particularly a plastic film, It has excellent mold releasability, and it has been found that the adhesion does not decrease even under conditions of high temperature and high humidity, and this composition can be applied to a substrate without solvent even if it is not diluted with an organic solvent. Yes, its curing is low temperature,
Since it can be carried out in a short time, the film treated with this does not shrink and does not adversely affect the adhesive substance even if it is in contact with the adhesive substance for a long time,
Further, it was confirmed that the present invention was excellent in peelability, and the present invention was completed.

[0007]

The silicone composition for release paper of the present invention comprises 1) an organopolysiloxane represented by the formula (1)
9) parts by weight of the organopolysiloxane represented by the formula (2) and 9) to 0.1 parts by weight of the organopolysiloxane represented by the above formula (2); Is an addition-reaction type organosiloxane composition characterized by comprising platinum or a platinum compound, which can be adhered to the surface of paper, laminated paper, plastic film, etc. without containing an organic solvent. Can,
This has the advantage that non-stickiness can be imparted to these substrate surfaces.

The organopolysiloxane as the first component constituting the peelable silicone composition of the present invention has an average composition formula represented by the following formula (1).

Embedded image Wherein R ¹ is an alkenyl group such as a vinyl group, an allyl group, or a hexenyl group; R ² , R ³ , and R ⁴ are each an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, or a cyclohexyl group; Alkenyl groups such as cycloalkyl group, vinyl group and allyl group; aryl groups such as phenyl group and tolyl group; or chloro in which part or all of the hydrogen atoms bonded to these carbon atoms are substituted with halogen atoms, cyano groups, etc. Unsubstituted or substituted 1 such as methyl group, trifluoropropyl group, cyanoethyl group, etc.
An atom or group selected from an alkoxy group such as a valent hydrocarbon group, a methoxy group, an ethoxy group, a propoxy group and a methoxyethoxy group, a hydroxyl group, an epoxy group, and the like; e
Is an organosiloxane in which 3 ≦ e ≦ 100, f is an integer of 10 to 1,000, and g is an integer of 1 to 50. It is preferable that at least 80% of all the organic groups are methyl groups.

[0009] Si in the organopolysiloxane
If the amount of the alkenyl group bonded to is less than 0.1 mol%, the curability is poor, and if the amount is more than 20 mol%, the cured film obtained from this composition has a large peeling resistance, so that the pressure-sensitive adhesive is practically used. Since the release from the mold becomes unstable, it is desirable to set the range of 0.1 to 20 mol%.

The organopolysiloxane as the second component constituting the release silicone composition of the present invention has an average composition formula represented by the following formula (2):

Embedded image Wherein R ⁵ is an alkenyl group such as a vinyl group, an allyl group or a hexenyl group, preferably a vinyl group, and R ⁶ is an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, or a cycloalkyl group such as a cyclohexyl group. Groups, phenyl groups, aryl groups such as tolyl groups, and chloromethyl groups and trifluoropropyl groups in which part or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with halogen atoms, cyano groups, etc. , A non-substituted or substituted monovalent hydrocarbon group selected from a cyanoethyl group and the like, and it is desirable that 80% or more of all organic groups be a methyl group from the viewpoint of releasability, and p is p ≧ 0, preferably Is p = 0
And q is such that q ≧ 1, but this may be any value as long as the viscosity at 25 ° C. falls within the range of 50 to 10,000 cp. The viscosity is preferably 100 to 400 cp from the viewpoint of coatability and the like.

This organopolysiloxane exhibits excellent curability by having an alkenyl group at the end of the molecular chain. This effect is greater as the content of the alkenyl group in the molecule is smaller. A plurality of alkenyl groups are more excellent in curing speed than one. Note that the organosiloxane as the first component and the organopolysiloxane as the second component generally have a thickness of 5 μm on the surface to be treated.
m or less, but if the viscosity at 25 ° C. is less than 50 cp or greater than 10,000 cp, the thin film coatability becomes inferior.
It is preferably in the range of 0,000 cp, preferably in the range of 100-3,000 cp, and more preferably in the range of 100-300 cp.

Next, the organohydrogenpolysiloxane as the third component constituting the peelable silicone composition of the present invention may be a known one used in this kind of addition-reaction type silicone composition. The organic group may have at least two, preferably at least three, hydrogen atoms bonded to silicon atoms, and the other organic groups preferably have at least 80 mol% of methyl groups. .

As this kind of polysiloxane, (CH ₃ ) HSi
O units, HSiO _1.5 units, (CH ₃ ) ₂ SiO units, CH ₃ SiO _1.5 units, (CH ₃ ) ₂ HSiO _0.5 units or homopolymers or copolymers composed of (CH ₃ ) ₃ SiO _0.5 units are exemplified, It may be linear, branched or cyclic,
Those having a viscosity at 10 ° C. in the range of 10 to 10,000 cp are preferred.

The amount of the polysiloxane may be determined according to the amount of the alkenyl group contained in the first component, the second component, and the third component. The molar ratio of C may be in the range of 1 to 10, but usually in the range of 1.0 to 100 parts by weight based on 100 parts by weight of the mixture of the first and second components from the viewpoint of cured film formation and release performance. And it is sufficient.

The fourth component in the peelable silicone composition of the present invention is used as a catalyst for causing the above-mentioned first to third components to undergo an addition reaction. This is known as a reaction catalyst of this type. Examples thereof include chloroplatinic acid, an alcohol solution of chloroplatinic acid, an aldehyde solution, a complex salt of chloroplatinic acid with various olefins, and vinyl siloxane. May be carried. In addition, this addition amount may be a catalyst amount, and in order to obtain a good cured film, and from an economical point of view, as a platinum amount with respect to 100 parts by weight of the blend of the first component, the second component, and the third component. The range may be 1 to 1,000 ppm.

The releasable silicone composition of the present invention can be obtained by blending a predetermined amount of the above-mentioned first to fourth components. It is preferable to add various organic nitrogen compounds, organic phosphorus compounds, acetylene compounds, and the like for the purpose of suppressing the activity of the platinum catalyst as the fourth component.
An activity inhibitor such as an oxime compound or an organic chloro compound may be added as necessary.

When the composition of the present invention is applied to an object to be treated, it may be applied as it is, and may be used by diluting it with a solvent as necessary. Depending on the conditions, r-glycidoxypropyltrimethoxysilane, r-methacryloxypropyltrimethoxysilane or a co-hydrolysate thereof may be added as an auxiliary agent for improving the adhesion to the substrate, Inorganic fillers such as dry process silica such as silica, wet process silica, titanium oxide, potassium oxide, carbon black, and mica;
A pigment or the like may be added.

The composition of the present invention may be applied to, for example, polyethylene laminated paper or various plastic films by a known technique such as a roll coater, a gravure coater, an air coater, a curtain flow coater, and an offset transfer roll coater.

The substrate treated with the composition of the present invention
A cured film may be formed on the surface by heating at a temperature of ~ 200 ° C for 1 to 30 seconds, but this composition can be thinly coated on a substrate without being diluted with an organic solvent. It is energy-saving, safe, and pollution-free, and can be applied to plastic films and the like without shrinking because this curing can be performed at a low temperature and in a short time as described above. It adheres well to substrates, especially plastic films, etc. and exhibits excellent release properties and abrasion resistance. Therefore, it is particularly useful for release treatment of plastic films.

[0020]

EXAMPLES Next, synthetic examples, examples and comparative examples of the first component used in the examples of the present invention will be described. In the examples, parts are parts by weight, and viscosities are measured values at 25 ° C. It is a thing. The methods for measuring various physical properties in the examples are described below.

[Curability] A predetermined amount of the composition is applied to the surface of a thin film or sheet substrate, and then heated for a predetermined time in a hot air circulating drying oven at a predetermined temperature to completely cure the coating. Measure the time to do so. However, this hardening was judged when the coated surface did not fall off even when the coated surface was rubbed with a finger and was not cloudy. [Adhesion] The thin film on which the cured film was formed by the above method was stored in a constant temperature / humidity bath at 40 ° C x 95% RH for a predetermined number of days, and the cured film was rubbed with a finger ten times vigorously until whitening and falling off. The degree of adhesion is indicated by the time (days).

[Release Force] The silicone composition was applied to an OPP film (40 μm) so that the coating amount was 0.5 g / m ^2, and heat-treated at 120 ° C. for 30 seconds in a hot-air circulation drying oven. After curing the coating, the substrate is allowed to stand at 25 ° C for 1 day,
Then, a rubber-based solvent-based adhesive BPS-3942 [trade name of Toyo Ink Mfg. Co., Ltd.] is applied to this surface so that the solid content becomes 25 g / m ^2, and dried at 100 ° C. for 3 minutes. (40 μm), and after one reciprocating pressure bonding with a 2 kg rubber roll, allowed to stand at 25 ° C. for 1 day and a test piece for peel force measurement (width 5 c
m) was prepared and the peeling force was measured using an autograph at a peeling angle of 180 ° and a peeling speed of 0.3 m / min. Similarly, the peeling sound when peeling at a peeling speed of 30 m / min was evaluated. [Residual adhesion rate] Lumirror 31B tape [trade name, manufactured by Nitto Denko Corporation] is bonded to the silicone-treated film obtained above, and a pressure of 20 g / cm ² is applied at 70 ° C for 20 hours. In order to measure the adhesive strength, a similar lumirror 31B was bonded to a Teflon plate and subjected to the same pressure bonding process.
After one reciprocation of the rubber roller, the adhesive force was measured, and the residual adhesive ratio of each sample was expressed as a percentage, with the adhesive force of Lumirror 31B as a reference being 100.

Synthesis Example After 68 parts of methyltrimethoxysilane and 444 parts of octamethylcyclotetrasiloxane were polymerized for 5 hours in the presence of an alkali catalyst, unreacted substances were distilled off under reduced pressure.
Since 300 parts of a polymer of 20 cp was obtained, 140 parts of tetramethyldivinyldisiloxane was added to 300 parts of the polymer,
These were hydrolyzed and condensed in hydrochloric acid water, and the low-boiling components were distilled off under reduced pressure.

Embedded image And 320 parts of a polyvinylsiloxane having a viscosity of 70 cp (hereinafter abbreviated as component A).

Example 1 50 parts of the component A obtained in the above synthesis example, both ends of the molecular chain were blocked with a trivinylsilyl group, the polymerization degree was 150, and the viscosity was 600.
cp dimethylpolysiloxane (hereinafter abbreviated as component B)
50 parts, 20 parts of methyl hydrogen polysiloxane (hereinafter abbreviated as component C) having 90 mol% of CH ₃ HSiO units and a viscosity of 100 cps, the molecular chain end of which is blocked with a trimethylsilyl group, and 20 parts of 3-methyl-1 1 part of butyne (hereinafter abbreviated as component D) is uniformly mixed and stirred, and 3 parts of a complex of chloroplatinic acid and vinylsiloxane (80 ppm in terms of platinum) (hereinafter abbreviated as component E) is added to the silicone composition. Thing (I)
made.

Next, this composition was applied to a polypropylene film having a thickness of 40 μm by using an offset transfer machine at 0.5 g / m ^2.
After coating and heating at 100 ° C to cure, the curability of this coating film, the adhesion of the resulting cured film,
When the peeling force and the residual adhesive ratio were examined, the results as shown in Table 1 below were obtained.

Example 2 50 parts of component A, 50 parts of polyvinylmethylsiloxane having a viscosity of 5,000 cps (hereinafter abbreviated as component F), both ends of which are blocked with a vinyldimethylsilyl group, 20 parts of component C, and 1 part of component D After uniformly mixing and stirring, 3 parts of Component E was added to prepare a silicone composition (II), which was treated and cured in the same manner as in Example 1 to a polypropylene film, and the physical properties of the cured film were examined. The results were as shown in Table 1 below.

Comparative Example 1 100 parts of component A, 20 parts of component C, and 1 part of component D were uniformly mixed and stirred, and 3 parts of component E was added thereto.
I) was prepared and processed into a polypropylene film in the same manner as in Example 1, cured, and the physical properties of the cured film were examined. The results shown in Table 1 below were obtained.

Comparative Example 2 After uniformly mixing and stirring 100 parts of the component B, 20 parts of the component C, and 1 part of the component D, 3 parts of the component E were added thereto to prepare a silicone composition (IV). The film was treated with a polypropylene film and cured, and the physical properties of the cured film were examined. The results were as shown in Table 1 below.

Comparative Example 3 100 parts of Component F, 20 parts of Component C and 1 part of Component D were uniformly mixed and stirred, and then 3 parts of Component E was added thereto to prepare a silicone composition (V). The film was treated with a polypropylene film and cured, and the physical properties of the cured film were examined. The results shown in the following Table 1 were obtained.

[0030]

[Table 1]

[0031]

The present invention relates to a releasable silicone composition comprising, as described above, 1) 0.1 to 99.9 parts by weight of an organopolysiloxane represented by the formula (1);
99.9 to 0.1 of the organopolysiloxane represented by the formula (2)
Parts by weight, 3) organohydrogenpolysiloxane
1.0 to 100 parts by weight, 4) a catalyst comprising platinum or a platinum compound in a catalytic amount.
It has the advantage that it can be applied in close contact with the surface of a plastic film or the like, and can impart non-adhesion to the surface of these substrates.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-181357 (JP, A) JP-A-60-88068 (JP, A) JP-A-50-141591 (JP, A)

Claims (1)

(57) [Claims] (1) The average composition formula is: (Where R ¹ is an alkenyl group, R ² , R ³ , and R ⁴ are the same or different monovalent organic groups, e is 3 ≦ e ≦ 100, and f is 10 to
1,000, g is an integer of 1 to 50) and an organopolysiloxane having a viscosity at 25 ° C. of 50 to 10,000 cp is 0.1 to 0.1 g.
99.9 parts by weight, 2) The average composition formula is (Where R ⁵ is an alkenyl group, R ⁶ is the same or different monovalent hydrocarbon group , a is a positive number of 1 to 3, p ≧ 0, q ≧ 1)
99.9 to 0.1 parts by weight of an organopolysiloxane having a viscosity at 25 ° C of 50 to 10,000 cp; 3) 1.0 to 100 parts by weight of an organohydrogenpolysiloxane; 4) a catalytic amount of platinum or a platinum-based compound. A silicone composition for release paper, comprising: