JP2630179B2 - Organopolysiloxane composition for release paper and release paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organopolysiloxane composition for release paper capable of forming a uniform film without defects such as pinholes, and a release paper coated with the composition and cured.

[0002]

2. Description of the Related Art Conventionally, release paper having a silicone cured film having excellent releasability formed on the surface of paper or plastic film has been widely applied to pressure-sensitive adhesive products.

As an organopolysiloxane composition capable of forming such a cured silicone film, an addition reaction type composition containing a vinyl group-containing organopolysiloxane, an organohydrogenpolysiloxane and an addition reaction catalyst is well known. Yes (Japanese Patent Publication 52-40918)
No., JP-B-61-53383).

[0004] However, this addition-reactive organopolysiloxane composition is suitable for those having a relatively small peeling force such as adhesive labels, tapes, and wallpaper, but is not suitable for process paper or double-sided tape. In fields requiring a large peeling force (heavy peeling force), such as those described above, its use is significantly restricted, and there is a problem in practicality.

[0005] In order to solve this problem, as a heavy release adjuster for adjusting the release force, a toluene soluble agent comprising R ₃ SiO _1/2 (R is a monovalent hydrocarbon group) and a unit represented by SiO ₂ is used. A method of adding a copolymer has been proposed (JP-A-52-86985).

However, when the organopolysiloxane composition using this release force adjusting component is applied to a base material, cissing or pinholes are generated, and the coating cannot be applied uniformly. After laminating the agents, there was a problem that heavy peeling or peeling failure occurred partially.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an organopolysiloxane composition for release paper which has excellent coatability and can be applied thinly and uniformly without forming pinholes or the like on a substrate. An object of the present invention is to provide a release paper on which a cured film of the composition is formed.

[0008]

Means for Solving the Problems and Action The present inventors have conducted intensive studies to achieve the above object, and as a result, (A) an alkenyl having at least two alkenyl groups directly bonded to a silicon atom in one molecule. 100 parts by weight of a group-containing diorganopolysiloxane; (B) 0.1 to 20 parts by weight of a liquid organohydrogenpolysiloxane containing at least two hydrogen atoms directly bonded to a silicon atom in one molecule; wherein _R 3 _{SiO 1/2} (wherein, R is methyl and / or vinyl group)及beauty solvent-soluble organopolysiloxane emissions 5-100 parts by weight of a siloxane unit represented by SiO _2, (D) For release paper containing 0.001 to 10 parts by weight of a perfluoroalkyl group-containing organopolysiloxane represented by the following formula (1), and (E) a catalyst amount of an addition reaction catalyst. It has been found that it is effective to use an organopolysiloxane composition.

[0009]

Embedded image Wherein R ¹ is an alkyl group, an aryl group or an aralkyl group having 1 to 18 carbon atoms, and R ² is C ₂ H ₄ C _n F
A perfluoroalkyl group represented by _{2n + 1} (n is an integer of 1 to 8), k is an integer of 1 or more, and m is 0 or an integer of 1 or more. ]

That is, the addition reaction type organopolysiloxane composition comprising the components (A), (B) and (E) and the release force modifier (C) are blended as described above. When applied to a material, there was a problem that defects such as pinholes occurred and the coating could not be applied uniformly. However, as a result of studying the cause, the present inventor found that the component (C) was used as a release control agent. When blended, the organopolysiloxane composition is easily foamed, and the foam is hard to disappear, and when coated on paper or a plastic film substrate in that state, the foam becomes a nucleus, thereby causing repelling, It was found that pinholes occurred. Therefore, as a result of further study to solve the problem that occurs when the component (C) is blended, the foaming is effectively suppressed when the perfluoroalkyl group-containing organopolysiloxane of the component (D) is blended. , Uniform coating without defects such as cissing and pinholes, and the compounding of the component (D) solves the problem of the compounding of the component (C) of the release force adjusting agent. The effect of the adjuster is effectively exhibited, and the release force can be adjusted without lowering the adhesive strength of the adhesive.The release paper on which a uniform cured film is formed has no pinholes, etc. The present invention has been found to have good peeling properties without causing heavy peeling or poor peeling, and has led to the present invention.

Accordingly, the present invention provides an organopolysiloxane composition for release paper, which contains the components (A) to (E), and a release paper obtained by applying and curing the composition. provide.

Hereinafter, the present invention will be described in more detail. As described above, the organopolysiloxane composition for release paper of the present invention contains the above components (A) to (E) as essential components.

The alkenyl group-containing diorganopolysiloxane as the component (A) constituting the composition of the present invention must contain at least two alkenyl groups directly bonded to silicon atoms in one molecule, and are preferably used. Those containing 0.002 to 0.15 mol of alkenyl groups in 100 g of diorganopolysiloxane are preferred. The organopolysiloxane may be linear or branched, and may be a mixture thereof. Examples of the organic group directly bonded to a silicon atom other than the alkenyl group include an alkyl group such as a methyl group, a propyl group, a butyl group and a hexyl group; an aryl group such as a phenyl group and a tolyl group; a β-phenylethyl group; Aralkyl groups such as phenylpropyl group; substituted or unsubstituted monovalent hydrocarbon groups such as halogen-substituted hydrocarbon groups such as chloromethyl group; among them, ease of synthesis and releasability from adhesive substances. A methyl group is preferred from the viewpoint that a cured film having excellent resistance can be obtained.
The viscosity of the organopolysiloxane (A) is not particularly limited, but is preferably 60 cs or more from the viewpoint of curability. In addition, it is possible to use a high-viscosity material of 50,000 cs or more, but when using such a high-viscosity material, it is necessary to dissolve it in an organic solvent to form a coating film of several μm or less. Is good.

As the organohydrogenpolysiloxane as the component (B), one having at least two hydrogen atoms (≡SiH) directly bonded to silicon atoms in one molecule is used. This organohydrogenpolysiloxane is
It may be linear, branched, or cyclic, but it needs to be liquid at room temperature. Specifically, the viscosity at 25 ° C. is preferably in the range of 10 to 300 cs. Further, as the organic group other than the hydrogen atom directly bonded to the silicon atom, the organic groups exemplified for the organopolysiloxane of the above-mentioned component (A) can be similarly exemplified.

Examples of such an organohydrogenpolysiloxane include α, ω-bis (dimethylhydrogensilyl) polydimethylsiloxane and α, ω-
Bis (trimethylsilyl) polymethylhydrogensiloxane, α, ω-bis (trimethylsilyl) poly (methylhydrogen) (dimethyl) siloxane copolymer and the like can be mentioned.

Component (B) is used in an amount of 0.1 to 20 parts, especially 2 to 1 part, per 100 parts (parts by weight, hereinafter the same) of the alkenyl group-containing organopolysiloxane of component (A).
A range of 5 parts is preferred. If the amount is less than 0.1 part, the curability of the obtained release paper composition may be poor. If the amount is more than 20 parts, the adhesive substance of the cured film obtained from the release paper composition may be used. May become unstable. The molar ratio of the ≡SiH group in the component (B) to the alkenyl group in the components (A) and (C) is preferably in the range of 0.5 to 10 for alkenyl group / ≡SiH group. .

Next, the solvent-soluble organopolysiloxane (C) constituting the composition of the present invention is a component for adjusting the heavy release property of the present release paper composition.
₃ SiO _1/2 (wherein R is a methyl group and / or a vinyl group) and a siloxane unit represented by SiO ₂ . In this case, the molar ratio between the R ₃ SiO _1/2 unit and the SiO ₂ unit is R ₃ SiO _1/2 unit / SiO ₂ unit = 0.6 to
1.3 is preferable, and the content of the vinyl group is
The range of 0 to 0.2 mol / 100 g is preferred. The organopolysiloxane of the component (C) must be soluble in a solvent, and examples of such a solvent include toluene, xylene, and n-hexane.

The amount of the component (C) is preferably 5 to 100 parts, more preferably 10 to 50 parts, per 100 parts of the alkenyl group-containing organopolysiloxane of the component (A). If the amount is less than 5 parts, the intended release force may not be controlled, while if it is more than 100 parts, the curability of the present release paper composition may be poor.

The perfluoroalkyl group-containing organopolysiloxane as the component (D) constituting the composition of the present invention controls the foaming property of a processing solution when a thin film, for example, a thin film of about 1 μm is formed on a substrate, In addition, it is a component for improving the leveling property and preventing generation of an uncoated portion on the base material, and is represented by the following formula (1).

[0020]

Embedded image

In the formula (1), R ¹ is a substituted or unsubstituted alkyl group, aryl group or aralkyl group having 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl and the like. An aryl group such as a phenyl group and a tolyl group; an aralkyl group such as a benzyl group; among them, a methyl group is preferable because of ease of synthesis. R ₂ is C ₂ H ₄ C _{nF
2n +} 1 (n is an integer of 1 to 8) are perfluoroalkyl groups represented by, for example, _{-C 2 H 4 CF 3, -C} 2 H 4
C ₄ F _9, and the like _{-C 2 H 4 C 8 F 17} . k
Is an integer of 1 or more, and m is 0 or an integer of 1 or more, and is not particularly limited, but 50 ≦ k + m ≦ 1000 and 20 ≦ k / (k + m) from the viewpoint of solubility in an organic solvent, defoaming property, and leveling property.
Preferably, the number satisfies ≦ 60.

The amount of the component (D) is 0.001 to 10 parts, preferably 0.01 to 100 parts of the component (A).
A range of ~ 5 parts is preferred. If the amount is less than 0.001 part, foaming is large when the present composition is applied to a substrate, and the leveling property may be insufficient.
If the amount is more than the number of parts, the cured film applied to the substrate and cured may reduce the adhesiveness of the adhesive.

The addition reaction catalyst constituting the component (E) of the present invention is a catalyst for reacting an alkenyl group with a hydrosilyl group (≡SiH), and employs a known catalyst used in such a reaction. Can be, for example, platinum black,
Chloroplatinic acid, chloroplatinic acid-olefin complex, rhodium-
Noble metal catalysts such as olefin complexes and chloroplatinic acid-vinylsiloxane complexes can be suitably used. The amount of the component (E) is a catalytic amount, and
The metal is usually 5 to 100 based on the total amount of the component (D).
Although it can be used in the range of 0 ppm, it can be appropriately adjusted according to the reactivity, economy, or desired reaction rate of these components (A) to (D).

The organopolysiloxane composition for release paper of the present invention can be obtained by uniformly mixing the above-mentioned components (A) to (E) in a predetermined amount. If necessary, a reaction inhibitor and silica may be used. Inorganic fillers, pigments and the like.

The thus obtained organopolysiloxane composition for release paper of the present invention can be used as it is without solvent.
Alternatively, it is diluted with an appropriate solvent such as toluene, xylene, n-hexane, or the like, and is coated on paper, a plastic film, or the like using a coating method such as roll coating, reverse coating, or gravure coating, and cured by heating. Thereby, a release paper can be manufactured. In this case, the coating amount is generally in the range of 0.05 to 50 g / m ² , and the heating condition is generally in the range of 80 to 180 ° C. for 4 to 60 seconds.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, parts are parts by weight, and viscosity is a value measured at 25 ° C.

Example 1 As a component (A), a vinyl group-containing dimethyl having a vinyl group content of 0.015 mol / 100 g and a degree of polymerization of about 8000, in which both ends of the branched chain were blocked with dimethylvinylsilyl groups. 100 parts of diphenylpolysiloxane (phenyl group content: 5 mol%), as component (B): {SiH whose both ends of the branched chain are blocked with trimethylsilyl groups
5 parts of methylhydrogenpolysiloxane having a base amount of 1.6 mol / 100 g and a viscosity of 20 cs. As the component (C), the formula (CH ₃ ) ₂ SiO _0.5 and the formula (CH ₃ ) (CH ₂
ＣＨCH) SiO _0.5 and xylene-soluble organopolysiloxane resin consisting of siloxane units of formula SiO ₂ (molar ratio 1.0: 0.05: 1.0) at a solid content of 25
In addition, 2 parts of acetylene alcohol was further added, and the mixture was diluted and dissolved with toluene so that the total weight became 2500 parts, to thereby obtain composition A.

This composition A was placed in five 100 ml lidded bottles, each 30 parts. As the component (D), a perfluoroalkyl group-containing organopolysiloxane represented by the following formula (1-a) was added to the vinyl group-containing organopolysiloxane of the component (A) in the composition A in an amount of 20: 1.
Samples 1 to 4 were added so as to be 00, 1000 and 10000 ppm, and samples 5 were not added for comparison.

[0029]

Embedded image

To each of these samples 1 to 5, 50 ppm of chloroplatinic acid-tetramethyldivinyldisiloxane complex as platinum was added as a component (E) to prepare a composition for release paper.

Next, the foamability of the obtained release paper composition was evaluated by the following method, and the composition was applied to the surface of polyethylene laminated paper using a wire bar at a coating amount of about 0.5 g / m ^2. Coated to become 140
A heat treatment was performed for 30 seconds in a hot air circulating drier at ℃ to obtain a release paper.

With respect to the cured film of the release paper, the peeling force and the residual adhesion were measured according to the following methods, and pinholes on the cured film surface were visually observed. Table 1 shows the above results.
Shown in 30 g of each of the above samples 1 to 5 was placed in a 100 ml glass bottle with a transparent lid having a foaming diameter of 4 cm, shaken with a shaker for 30 minutes, allowed to stand for 2 minutes, measured for the liquid level, and shaken according to the following formula. Foamability was evaluated based on the ratio to the height of the liquid level before. Foaming property = H / H ₀ × 100 (%) (H: height to the liquid surface after shaking, H ₀ : height of the liquid surface before shaking) Peeling force Acrylic solvent on the surface of the cured film of glassine paper piece Type Adhesive (Orivine BPS-512, manufactured by Toyo Ink Co., Ltd.)
7) Alternatively, an acrylic emulsion-type pressure-sensitive adhesive (manufactured by Toyo Ink Co., Ltd., trade name: Olivine BPW-3110H) was applied, followed by heat treatment at 100 ° C. for 3 minutes to prepare a paper piece having a pressure-sensitive adhesive layer on the cured film. Next, a bonding paper having a basis weight of 64 g / m ³ was bonded to the pressure-sensitive adhesive layer of the paper piece and aged at room temperature for 20 hours. After aging, a piece of paper was cut into a piece having a width of 5 cm and a length of 10 cm to prepare a test piece.
The force (g / 5 cm width) required for the cured film to peel from the pressure-sensitive adhesive layer was measured. Residual Adhesion Rate A polyester adhesive tape (trade name: Lumirror 31B, manufactured by Nitto Denko Corporation) is adhered to the surface of the cured film of the release paper, and a pressure of 20 g / cm ² is applied at 70 ° C.
Heated for hours. After the heat treatment, the polyester pressure-sensitive adhesive tape was peeled off from the cured film and attached to the surface of a stainless steel plate.

Next, the heat-treated polyester pressure-sensitive adhesive tape was peeled off from the stainless steel plate in a direction of 180 ° at a peeling speed of 300 mm / min, and a force W required for peeling was obtained.
(G / 2.5 cm width) was measured. On the other hand, a polyester adhesive tape not subjected to the heat treatment was applied to a stainless steel plate, and the force W ₀ (g / 2.5c) required to peel the tape from the stainless steel plate under the same conditions as above.
m width) was measured, the ratio of W to the W ₀ (W / W ₀₎
(Percentage) was determined and defined as the residual adhesion rate.

[0034]

[Table 1]

Example 2, Comparative Example As the component (A),
With respect to 60 parts of dimethylpolysiloxane having a polymerization degree of 60, both ends of the molecular chain being blocked with a dimethylvinylsilyl group,
As the component (C), toluene-soluble formula (CH ₃ ) ₂ Si
After adding an organic polysiloxane resin consisting of O _0.5 and a siloxane unit represented by the formula SiO ₂ (molar ratio: 0.8: 1.0) in an amount of 40 parts by solid content, the solvent was distilled off, and as a component (B), a molecule was obtained. Both ends of the chain are blocked with trimethylsilyl groups. The amount of SiH groups is 1.6 mol / 100 g and the viscosity is 20 c.
3 parts of methylhydrogenpolysiloxane and 1 part of acetylene alcohol were added to prepare a solventless composition B for release paper.

Sample 6 obtained by adding 100, 1000, and 10000 ppm of the perfluoroalkyl group-containing organopolysiloxane represented by the formula (1-a) used in the above-mentioned Examples as the component (D) to 10 parts of the composition B, respectively. , 7, and 8 were prepared, and as a comparison, Sample 9 to which the organopolysiloxane was not added was obtained.

To each of these samples 6 to 9, 50 ppm of a chloroplatinic acid-tetramethylvinyldisiloxane complex was added as a component (E), and the mixture was thoroughly mixed. The foamability was evaluated in the same manner as described above. Further, these compositions were applied to the surface of polyethylene laminated paper using a printability tester so that the amount of silicone applied was about 0.5 g / m ² . At this time, it was recognized that the leveling of the coated surface was better when samples 6 to 8 were applied than when sample 9 was applied. Next, heat treatment was performed in a hot air circulating dryer at 150 ° C. for 20 seconds, and the obtained film was measured for peeling force and residual adhesive force in the same manner as in Example 1. Table 2 shows the results. The peeling force was 1 at 70 ° C. and a pressure of 20 g / cm ² after laminating No. 502 tape manufactured by Nitto Denko Corporation.
The measurement was performed after the day pressing.

[0038]

[Table 2]

[0039]

The organopolysiloxane composition for release paper of the present invention is capable of forming a uniform release film on a substrate, and the release paper obtained by coating and curing the composition is a pinhole or the like. A good film having no peeling was formed, and had good peeling properties.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location D21H 19/32 D21H 1/34 P

Claims (2)

(57) [Claims] (A) 100 parts by weight of an alkenyl group-containing diorganopolysiloxane having at least two alkenyl groups directly bonded to silicon atoms in one molecule; (B) direct bonding to silicon atoms in one molecule 0.1 to 20 parts by weight of a liquid organohydrogenpolysiloxane containing at least two hydrogen atoms, represented by the formula (C): R ₃ SiO _1/2 (wherein R is a methyl group and / or a vinyl group) And 5 to 100 parts by weight of a solvent-soluble organopolysiloxane having a siloxane unit represented by SiO ₂ , and (D) a perfluoroalkyl group-containing organopolysiloxane represented by the following formula (1) 0.001 to 10: Parts by weight, Wherein R ¹ is an alkyl group, an aryl group or an aralkyl group having 1 to 18 carbon atoms, and R ² is C ₂ H ₄ C _n F
A perfluoroalkyl group represented by _{2n + 1} (n is an integer of 1 to 8), k is an integer of 1 or more, and m is 0 or an integer of 1 or more. ] (E) an addition reaction catalyst, an organopolysiloxane composition for release paper, comprising a catalytic amount of: 2. A release paper obtained by applying and curing the organopolysiloxane composition for release paper according to claim 1 onto a substrate.