JP3242555B2 - Curable silicone composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicone composition which is cured by short-time heating or ultraviolet irradiation, and more specifically, for example, a surface treatment agent for a release film or release paper, a back surface treatment agent for an adhesive tape, The present invention relates to a curable silicone composition useful as a mold agent, a protective coating agent, a water repellent, an oil repellent, and the like.

[0002]

2. Description of the Related Art Generally, an adhesive surface such as an adhesive tape is coated with a release paper to prevent the adhesive surface from being contaminated with dust or the like. This release paper is coated with a release agent on the surface of a base material such as paper, processed paper, resin film, etc., so that it can be easily released from the adhesive surface.If the adhesive tape is a wound tape, The back surface of the tape coated with a release agent also serves as this.
Conventionally, as a releasing agent, an addition reaction-curable silicone composition comprising an organopolysiloxane having an alkenyl group bonded to a silicon atom, an organopolysiloxane having a hydrogen atom bonded to a silicon atom, and a platinum group metal-based curing catalyst Also, a photocationic reaction-curable silicone composition containing an organopolysiloxane having an epoxy group and an onium salt-based photoacid generator (see JP-A-56-38350) is known. However, when an addition-reaction-curable silicone composition is used as a release agent, the unreacted SiH groups remain in the cured product, and the releasability from the adhesive surface of the tape decreases over time. is there. Further, when a photo-cationic reaction-curable silicone composition is used as a release agent, an organopolysiloxane having an epoxy group is used. Not enough.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a silicone composition which can be cured by heating for a short time or irradiating ultraviolet rays, and the cured product can be applied to various adhesive surfaces comprising various adhesives. Shows good peelability, can maintain excellent peelability without deterioration over time even under high temperature, for example, surface treatment agent for release film or release paper, back surface treatment agent for adhesive tape, release agent, An object of the present invention is to provide a curable silicone composition useful as a protective coating agent, a water repellent, an oil repellent, and the like.

[0004]

According to the present invention, there is provided (A) a compound represented by the following general formula (1) in one molecule: R _a X _b SiO _{(4-ab) / 2} (1) wherein R is unsubstituted Or a substituted monovalent hydrocarbon group,
X is the following general formula (2):

Embedded image (Wherein, R ¹ is a divalent hydrocarbon group or an oxygen atom;
e is a methyl group), and a is 0 to 2
B is an integer of 1 to 3, and 1 ≦ a +
b is an integer satisfying b ≦ 3].
A curable silicone composition containing 100 parts by weight of the organopolysiloxane having the above and (B) 0.01 to 30 parts by weight of a curing agent.

Hereinafter, the present invention will be described in detail. Component (A) Organopolysiloxane The component (A) used in the composition of the present invention has two or more units represented by the above general formula (1) in one molecule, and is linear or branched. Any organopolysiloxane, in the form of a ring or a ring, may be used. Representative examples of the unsubstituted or substituted monovalent hydrocarbon group represented by R in the general formula (1) include those having 1 to 10 carbon atoms, and specifically, for example, methyl Group, ethyl group, propyl group,
Isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, alkyl group such as decyl group; cyclopentyl group, cyclohexyl group, cycloheptyl group, etc. Cycloalkyl group; alkenyl group such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, hexenyl group, cyclohexenyl group; aryl group such as phenyl group, tolyl group, xylyl group; benzyl group, Aralkyl groups such as phenylethyl group, phenylpropyl group and methylbenzyl group; and part or all of hydrogen atoms bonded to carbon atoms of these groups are halogen atoms such as fluorine, chlorine and bromine, cyano group,
A group substituted with a hydroxy group or the like, for example, a chloromethyl group, a 2-bromoethyl group, a 3-chloropropyl group,
3,3,3-trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, 3,3
4,4,5,5,6,6,6-nonafluorohexyl group, hydroxypropyl group and the like.

The group represented by X in the general formula (1) is
A cyclotrisiloxane structure-containing group represented by the general formula (2). In the general formula (2), R ¹ is a divalent hydrocarbon group or an oxygen atom. Examples of the divalent hydrocarbon group include an alkylene group such as a methylene group, an ethylene group and a propylene group; and a cycloalkyl group such as a cyclohexylene group. arylene groups such as phenylene group; an alkylene group following formula: -R ² O- (wherein, R ² is a is an alkylene group similar to above) oxyalkylene group represented by; the following formula: - (R ² O A polyoxyalkylene group represented by _n- (wherein, R ² is independently the same alkylene group as described above, and n is an integer of 2 to 20); A group in which two groups are bonded through the oxyalkylene group; a group in which two alkylene groups are bonded through the polyoxyalkylene group; and the like.

Specific examples of the group represented by X include:
For example, those represented by the following formula can be mentioned.

Embedded image

[0008] The organopolysiloxane of the component (A) used in the present invention, in addition to the unit represented by the general formula _{^{(1), R 3 3 SiO}} 1/2, R 3 2 SiO, R 3 SiO 3 / _Two
And an SiO ₂ unit [where R ³ is a group similar to the unsubstituted or substituted monovalent hydrocarbon group exemplified as R in the general formula (1) or a methoxy group, an ethoxy group, a propoxy group, or a butoxy group] Or an alkoxy group having 1 to 10 carbon atoms (however, when there are a plurality of R ^{3 s} , they may be the same or different)].

The proportion of the unit represented by the general formula (1) in the organopolysiloxane as the component (A) is usually 0.5 to 70 mol%, preferably 0.5 to 70 mol%, because of the ease of synthesis of the component. 1 to 40 mol%. Examples of the organopolysiloxane of the component (A) include, for example, the following average composition formula (3): R ³ _i X _j SiO _{(4-ij) / 2} (3) (wherein X and R ³ are as defined above) And i and j are
0 ≦ i ≦ 1.999, 0.005 ≦ j ≦ 2.100, 0.015 ≦ i + j
Which satisfies .ltoreq.3.000). The organopolysiloxane of the component (A) is preferably oily at room temperature, and the viscosity is not particularly limited.
~ 1,000,000cP, especially 50 ~ 10,000c
P is preferred.

[0010] Specific examples of such organopolysiloxane, for example, the following general _{^{formula: R 3 3 SiO- [R 3}} XSiO] L - [R 3 2 SiO] M -Si R 3 3 ( wherein, R ³ And X are the same as described above, and L is 2 ≦ L ≦
Is an integer of 2100, those M is represented by 2 ≦ L + a M ≦ 3000 to become an integer of 0 or more), the following general _{^{formula: R 3 2 XSiO - [R}} 3 XSiO] L - [R 3 2 SiO] _M -SiR ³ in ₂ X (wherein, R ³ and X are as defined above, L is 2 ≦ L ≦
Is an integer of 2100, those M is represented by a is) an integer of 0 or more to be 1 ≦ L + M ≦ 3000, the following general _{^{formula: [R 3 3 SiO 1/2]}} P - [R 3 XSiO] Q - [R ³ ₂ SiO] _R- [R ³ SiO
_3/2 ] _S (wherein, R ³ and X are the same as above, and Q is 2 ≦ Q ≦
An integer of 2100, P, R, and S are integers of 0 or more with 3 ≦ P + Q + R + S ≦ 3000), and the following general formula:

[0011]

Embedded image (Wherein, R ³ and X are the same as above, and L is 2 ≦ L ≦
An integer of 5 and M is an integer of 3 ≦ L + M ≦ 20)
And the like. Representative examples of such organopolysiloxanes include, for example, the following formulas Me ₃ SiO- [MeXSiO] _2- [Me ₂ SiO] ₈ -SiMe ₃ , Me ₃ SiO- [MeXSiO] _3- [Me ₂ SiO] _{25 -SiMe 3, Me 2 XSiO- [MeXSiO} ] 8 - [Me 2 SiO] 90 -SiMe 2 X, Me 2 XSiO- [Me 2 SiO] 18 -SiMe 2 X, Me 2 XSiO- [Me 2 SiO] 20 - _{SiMe 2 X, Me 3 SiO- [} MeXSiO] 4 - [Me 2 SiO] 15 - [MePhSiO] -SiMe 3, [Me 2 XSiO 1/2] 4 - [MeXSiO] 2 - [Me 2 SiO] 30 - [ MeSiO _3/2 ] ₂ ,

Embedded image (Where Me is a methyl group, Ph is a phenyl group, and X is the same as described above).

(B) Curing Agent As the curing agent used in the composition of the present invention, at least one selected from acids and acid generators or at least one selected from bases and base generators can be used. . Examples of the acid include Bronsted acids such as sulfuric acid, hydrochloric acid, methanesulfonic acid, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid, acetic acid, and trifluoroacetic acid; aluminum trichloride;
Lewis acids such as boron trifluoride, titanium tetrachloride, iron (III) chloride, zinc chloride, tin chloride, trialkylaluminum, zinc octylate, tin octylate, dibutyltin dilaurate, aluminum triacetylacetonate, dibutyltin dimethoxide And the like.

Examples of the acid generator include onium salt photoacid generators, onium salt thermal acid generators, triazine photoacid generators, sulfonic ester photoacid generators, and disulfone photoacid generators. And the like. Among them, onium salt-based photoacid generators are preferable in that the pot life of the obtained composition is prolonged. As the onium salt photoacid generator, for example, the following _{^{formula: R 4 2 I + · X}} - ( wherein, R ⁴ is, for example, a phenyl group, a tolyl group, a xylyl group, butylphenyl group, dodecylphenyl group, butoxy An aryl group such as a phenyl group and an octyloxyphenyl group, and X ⁻ is, for example, CF ₃ SO ₃ ⁻ , SbF ₆ ⁻ , AsF _{6
^{-, PF 6 -, BF 4}} -, HSO 4 -, ClO 4 -, Cl - diaryliodonium salt represented by anion in a), such as,
_{^{Formula: R 4 3 S + · X}} - ( wherein, R ⁴ and X ^- is same as that defined above) triarylsulfonium salt represented by the following _{^{formula: R 4 R 5 2 S +}} · X - ( In the formula, R ⁴ and X ⁻ are the same as described above, and R ⁵ is, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group), a monoaryldialkylsulfonium salt represented by the following formula: _{^{: R 4 3 Se + · X}} - ( wherein, R ⁴ and X ^- is same as that defined above) triarylselenonium salt represented by the following _{^{formula: R 4 4 P + · X}} - ( wherein, R ⁴ and X ^- are tetraarylphosphonium salt represented by the same in a) and the following formula: R ⁴ N ₂ ⁺ · X ^- Table in the same as above) ^- (wherein, R ⁴ and X Aryldiazonium salts and the like.

Examples of the base include metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkyl metals such as butyl lithium; metal alkoxides such as sodium methoxide and potassium methoxide; lithium silanolate And metal silanolates such as potassium silanolate; triethylamine, ethylenediamine, diethylenetriamine, 1,8-diazabicyclo [5.
4.0] primary, secondary or tertiary amines such as undec-7-ene, 1,4-diazabicyclo [2.2.2] octane; triphenylphosphine, tri (4-methoxyphenyl) phosphine, tributylphosphine And the like.

[0015] As before Kishio base generator, photobase generating agent
Yes, for example

Embedded image Is mentioned.

Among such curing agents, onium salt photoacid generators and Lewis acids are preferred in that the pot life of the resulting composition is prolonged. Component (B) is used in an amount of generally 0.01 to 30 parts by weight, preferably 0.1 to 30 parts by weight, per 100 parts by weight of the organopolysiloxane of component (A).
20 parts by weight. If the amount is too small, the curability of the composition may be insufficient. If the amount is too large, the cured product may have poor physical properties such as mechanical strength.

Other Components In addition to the above components (A) and (B), the composition of the present invention may further contain other curable resins as required. As the curable resin, for example, epoxy resin,
Cationic curable resins such as epoxy group-containing organopolysiloxane and vinyl ether group-containing organopolysiloxane; and anionic curable resins such as acrylic resin. Further, the composition of the present invention, an epoxy diluent,
A diluent such as a vinyl ether-based diluent and other organic solvents; a filler; an agent for improving adhesion to a substrate; a leveling agent; an antistatic agent; an antifoaming agent;

Uses of the Composition The composition of the present invention has a cured product having excellent releasability from a pressure-sensitive adhesive and excellent stability over time. Therefore, the composition of the present invention comprises a back surface treatment agent for an adhesive tape; a release agent for rubber, plastic, ceramics, etc .; a protective coating agent for metals, plastics, etc .;
Oil repellent; Water repellent and oil repellent for food packaging paper; Heat and chemical resistant coating agent; Vehicle or additive for paint; Printing plate for printing; Sealant;

The composition of the present invention can be used as a cured product in the form of a sheet or a thin film. In order to form the composition of the present invention into a sheet, the composition may be poured into a mold and cured. Further, in order to use a cured product of the composition of the present invention as a thin film, the composition may be applied to a substrate and cured. Examples of the substrate include paper substrates such as glassine paper, kraft paper, and clay-coated paper; laminated paper such as polyethylene-laminated high-quality paper and polyethylene-laminated kraft paper; polyester, polypropylene, polyethylene, polyvinyl chloride, and polytetrafluorocarbon. Synthetic resin films or sheets such as ethylene, polycarbonate, and polyimide; metal plates such as aluminum plates and copper plates; and ceramic plates such as glass plates.

Examples of the method of applying the composition of the present invention to the substrate include a roll coater coating method, a gravure coating method, a wire doctor coating method, an air knife coating method, and the like.
A dipping coating method, a coating method by offset printing, and the like are included. The amount of the composition applied to the substrate can be appropriately adjusted, but is usually 0.1% in thickness after curing.
It may be about μm to 5 mm.

The method for curing the composition of the present invention can be appropriately selected depending on the type of the curing agent of the component (B) blended in the composition. For example, when using the photoacid generator or photobase generator as a curing agent, it can be cured by irradiating ultraviolet rays, when using the acid or base or thermal acid generator, It can be cured by heating. Examples of the light source for the ultraviolet irradiation include a mercury arc lamp, a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, and a metal halide lamp. The irradiation conditions of the ultraviolet ray cannot be unconditionally determined depending on the thickness of the composition or the like. For example, a high-pressure mercury lamp (80
(W / cm), ultraviolet rays may be irradiated from a distance of 8 cm from the substrate surface for about 0.01 seconds to 10 minutes. The heating conditions when the composition of the present invention is cured by heating cannot be unconditionally determined by the thickness of the composition or the like. When a hot air circulation type drying furnace is used, the heating may be usually performed at a temperature of 70 to 200 ° C. for about 1 to 120 minutes.

[0022]

The present invention will be described more specifically below with reference to examples and comparative examples. In this example, Me represents a methyl group. Example 1 The following formula (4): Me ₃ SiO- [MeXSiO] _3- [Me ₂ SiO] ₂₅ -SiMe ₃ (4) [where X is the following formula (5):

Embedded image Is mixed with 100 parts by weight of the organopolysiloxane represented by the formula and 5 parts by weight of dodecylbenzenesulfonic acid to prepare a silicone composition. The silicone composition was poured into an aluminum mold, and then heated at 150 ° C. for 10 minutes using a hot-air circulation drying oven to obtain a rubbery sheet having a thickness of 2 mm.

Next, the above silicone composition is coated on polyethylene-laminated paper (resin side, the same applies hereinafter) in an amount of 2%.
g / m ² was applied using a wire bar.
Then, the laminated paper was heated at 150 ° C. for 10 minutes using a hot air circulation type drying furnace to form a flexible cured film on the laminated paper.

Example 2 A rubbery sheet was obtained in the same manner as in Example 1, except that 5 parts by weight of dibutyltin dimethoxide was used instead of dodecylbenzenesulfonic acid.

Example 3 A rubbery sheet was obtained in the same manner as in Example 1, except that 2 parts by weight of a saturated solution of potassium hydroxide in butanol at 25 ° C. was used instead of dodecylbenzenesulfonic acid. Was.

Example 4 In Example 1, 1,8-diazabicyclo [5.4.0] undeca was used instead of dodecylbenzenesulfonic acid.
A rubber-like sheet was obtained in the same manner as in Example 1 except that 5 parts by weight of 7-ene was used.

Example 5 A silicone composition comprising 100 parts by weight of the organopolysiloxane represented by the formula (4) used in Example 1, 2 parts by weight of a diaryliodonium salt (photoacid generator) and 50 parts by weight of methyl isobutyl ketone Was prepared. This silicone composition is coated on polyethylene-laminated paper in an amount of 2
g / m ² was applied using a wire bar.
Then, the laminated paper was irradiated with ultraviolet rays from a distance of 8 cm from the laminated paper with a high-pressure mercury lamp (80 W / cm) using a conveyor-type ultraviolet irradiation device to form a flexible cured film on the laminated paper. . In addition, the conveyor speed of the used ultraviolet irradiation apparatus was set to 30 m / min.

Example 6 In Example 5, instead of the organopolysiloxane represented by the formula (4), the following formula: Me ₂ XSiO- [Me ₂ SiO] ₁₈ -SiMe ₂ X [where X is A flexible cured film was formed on polyethylene laminated paper in the same manner as in Example 5 except that 100 parts by weight of the organopolysiloxane represented by the formula (5) was used.

Comparative Example 1 In the formula (4), the group represented by X is a β- (3,4-epoxycyclohexyl) ethyl group, 100 parts by weight of an organopolysiloxane, a diaryliodonium salt (photoacid generator) 2 A silicone composition comprising 50 parts by weight of methyl isobutyl ketone and 50 parts by weight of methyl isobutyl ketone was prepared. This silicone composition was coated on polyethylene laminated paper at a coating amount of 2 g /
m ² was applied using an offset transfer machine.
Then, this laminated paper was subjected to ultraviolet irradiation using a conveyor type ultraviolet irradiation apparatus under the same conditions as in Example 5. [Distance from the laminated paper: 8 cm, light source: high-pressure mercury lamp (80 W / cm), conveyor Speed: 30 m / min],
The composition on the laminated paper did not cure, but cured when the conveyor speed was changed to 10 m / min.

The curability of the silicone composition obtained in each of the above examples, the peeling strength of the obtained cured film, and the residual adhesion were evaluated by the following methods. Table 1 shows the results. Curability: When the silicone composition is thermosetting, the shortest heating time required to cure the silicone composition applied to the surface of the polyethylene laminated paper in a hot air circulating drying oven at 150 ° C. was measured and evaluated. . When the silicone composition is ultraviolet-curable, the silicone composition applied to the surface of the polyethylene laminated paper is exposed to ultraviolet light using a conveyor-type ultraviolet irradiation device [light source: high-pressure mercury lamp (80 W / cm)]. Irradiation from a distance of 8 cm from, and the highest conveyor speed required for curing was measured and evaluated. The hardening was confirmed when the surface of the film was strongly rubbed with a fingertip, and when the surface became cloudy or the film did not fall off, the hardening was performed.

Peeling force: Acrylic solvent-type adhesive (SK-801B manufactured by Soken Chemical Co., Ltd.) on the surface of the cured silicone composition film formed on polyethylene laminated paper.
Was applied and heated at 100 ° C. for 3 minutes. Next, a high-quality paper having a basis weight of 64 g / cm ² was stuck to the coated surface, and then cut into a 50 mm wide tape.
A test piece was prepared by aging for 4 hours or 48 hours at 70 ° C. (in Table 1, the former was referred to as aging 1 and the latter as aging 2). Then, the laminated paper and the high-quality paper of the test piece were peeled off using a tensile tester, and the load (g / 50 mm) at the time of peeling was measured. The peeling was performed under conditions that the end portions of the laminated paper and the high-quality paper were fixed to a tensile tester and the angle between the laminated paper and the high-quality paper was 180 degrees (peeling speed: 0.3 m / min). ).

Residual adhesion: 25% width on the surface of the cured silicone composition film formed on polyethylene laminated paper
mm polyester adhesive tape (3 manufactured by Nitto Denko Corporation)
1B) and 20 g / cm from the back of the tape
Aging was performed at 70 ° C. for 20 hours under a load of ² . Next, the adhesive tape was peeled off from the polyethylene laminated paper, and the adhesive tape was attached to a polyester film. Then, the polyester film and the adhesive tape were peeled off using the above-mentioned tensile tester, and the load (hereinafter referred to as load 1) at the time of peeling (g / 25 mm) was measured. The peeling conditions are the same as in the peeling force test described above. Next, apart from this, using the same adhesive tape except that it was not bonded to the silicone cured film, the polyester film and the adhesive tape were peeled off in the same manner as described above, and the load at the time of peeling (hereinafter referred to as load 2) (G / 25 mm) was measured. Then, 100 · load 1 / load 2 (%) was defined as the residual adhesion rate.

[0033]

[Table 1]

[0034]

The composition of the present invention can be cured by heating for a short time or irradiating ultraviolet rays, and the cured product shows good peelability even on various adhesive surfaces made of various adhesives. . In addition, the cured product can maintain excellent releasability without deterioration over time even at high temperatures. Therefore, the composition of the present invention is useful as, for example, a surface treatment agent for a release film or release paper, a back surface treatment agent for an adhesive tape, a release agent, a protective coating agent, a water repellent, an oil repellent, and the like.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshio Ohba 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory (56) References JP-A-8-3450 JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 83/04 C08L 83/06 C08K 5/00 C08G 77/04

Claims (3)

(57) [Claims] (A) A molecule represented by the following general formula (1): R _a X _b SiO _{(4-ab) / 2} (1) wherein R is an unsubstituted or substituted monovalent hydrocarbon group And
X is the following general formula (2): (Wherein, R ¹ is a divalent hydrocarbon group or an oxygen atom;
e is a methyl group), and a is 0 to 2
B is an integer of 1 to 3, and 1 ≦ a +
b is an integer satisfying b ≦ 3].
A curable silicone composition comprising 100 parts by weight of the above-mentioned organopolysiloxane and (B) 0.01 to 30 parts by weight of a curing agent. 2. The method according to claim 1, wherein the curing agent (B) is at least one selected from acids and acid generators or at least one selected from bases and base generators . Curable silicone composition. 3. The curable silicone composition according to claim 2, wherein the acid generator is an onium-based photoacid generator.