JP2003327664A - Ultraviolet-curable organopolysiloxane composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ultraviolet-curable organopolysiloxane composition which quickly cures by irradiation with ultraviolet rays, and can form a cured film having reduced peeling force. <P>SOLUTION: The ultraviolet-curable organopolysiloxane composition comprises (A) a resinous organopolysiloxane which is represented by the average composition formula (1): (ER<SB>2</SB>SiO<SB>1/2</SB>)<SB>a</SB>(R<SB>2</SB>SiO<SB>2/2</SB>)<SB>b</SB>(SiO<SB>4/2</SB>)<SB>c</SB>(wherein E is an epoxy group-containing organic group; R is a 1-10C monovalent hydrocarbon group; and (a), (b), and (c) are each a number of 1 or more, a/c is 3 or 4, and b/c is a number of 4 or more) and has a viscosity at 25°C, of 10-10,000 mPas, (B) a linear diorganopolysiloxane having, as the main skeleton, a siloxane unit represented by the formula: ERSiO<SB>2/2</SB>(wherein E and R are the same as defined above), and (C) an onium salt photoinitiator. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet-curable organopolysiloxane composition, and more specifically, it is an ultraviolet-curable composition which can be cured rapidly by irradiation with ultraviolet rays to form a cured film excellent in releasability from an adhesive substance. Organopolysiloxane composition.

[0002]

2. Description of the Related Art Organopolysiloxane compositions which can be cured by irradiation with ultraviolet rays to form a peelable cured film have been known. For example, Japanese Patent Application Laid-Open No. 56-38350 proposes an ultraviolet-curable organopolysiloxane composition comprising a linear diorganopolysiloxane having an epoxy group in the molecule and an onium salt-based initiator. However, in order to cure this composition promptly, it is necessary to contain an epoxy group in a high concentration, and as a result, there is a problem that the releasability of the cured film decreases.
In particular, there has been a problem that the peeling force at the time of high-speed peeling (peeling speed 100 m / min or more) becomes large. Also, 3
A composition comprising a branched epoxy group-containing organopolysiloxane having a functional siloxane unit and an onium salt photoinitiator has been proposed (see JP-A-4-159322). However, this composition also has a problem that the peeling force at the time of high-speed peeling (peeling speed 100 m / min or more) becomes large. Further, there are problems such as difficulty in synthesizing a branched epoxy group-containing organopolysiloxane having a homogeneous trifunctional siloxane unit, which is not sufficiently satisfactory depending on the application.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies in order to solve the above problems, and as a result, have a specific epoxy-functional organopolysiloxane having a tetrafunctional siloxane unit (Q unit) as a main component. The present inventors have found that the composition solves the above-mentioned problems, has a good curability, and forms a cured film having a small peeling force at the time of high-speed peeling, and thus reached the present invention. That is, the object of the present invention, by irradiation of ultraviolet rays,
An object of the present invention is to provide an ultraviolet-curable organopolysiloxane composition that can be rapidly cured to form a cured film having excellent releasability from an adhesive substance.

[0004]

According to the present invention, "(A) average composition formula (1): (ER ₂ SiO _1/2 ) _a (R ₂ SiO _2/2 ) _b (SiO _4/2 ) _c (1) (wherein, E is an epoxy group-containing organic group, R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, and a, b and c
Is a number of 1 or more, a / c is 3 or 4, b /
c is a number of 4 or more. ), And a resinous organopolysiloxane having a viscosity at 25 ° C. of 10 to 10,000 mPa · s (100 parts by weight), (B) Formula: (ERSiO _2/2 ) (wherein E and R are as described above). From the linear diorganopolysiloxane (0 to 99 parts by weight) having a siloxane unit as a main skeleton and the (C) onium salt photoinitiator (0.01 to 20 parts by weight). Which is a UV-curable organopolysiloxane composition. Regarding

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION To explain this, the component (A) is a component which is a feature of the present invention. The average composition formula (1): (ER ₂ SiO _1/2 ) _a (R ₂ SiO _{2 / 2} ) _b (SiO _4/2 ) _c ··· (1) (In the formula, E is an epoxy group-containing organic group, R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, and a, b and c
Is a number of 1 or more, a / c is 3 or 4, b /
c is a number of 4 or more. ) Is a resin-like organopolysiloxane represented by the formula (1). In the above formula, as the epoxy group-containing organic group of E, 3-glycidoxypropyl group, 2-glycidoxyethyl group, 2,3-epoxypropyl group,
3,4-epoxybutyl group, 4,5-epoxypentyl group, 5,6-epoxyhexyl group, 2- (3,4-epoxycyclohexyl) ethyl group, 2- (4-methyl-
The 3,4-epoxycyclohexyl) propyl group is exemplified. Examples of the monovalent hydrocarbon group for R include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group and octyl group; cycloalkyl groups such as cyclohexyl group, vinyl group, allyl group, 5 Examples include alkenyl groups such as hexenyl group; aryl groups such as phenyl group and tolyl group. Of these, a methyl group is preferable. The viscosity of this component is 10 to 10 at 25 ° C.
It is necessary to be 000 mPa · s, and 50 to 3,
It is preferably 000 mPa · s.

The component (A) is a monofunctional siloxane unit (ER ₂ SiO _1/2 ) having an epoxy group as described above.
Unit), an epoxy group-free difunctional siloxane unit (R ₂ SiO _2/2 ) and a tetrafunctional siloxane unit (SiO 2
It is a resin-like organopolysiloxane composed of _4/2 units), but these siloxane units may be connected in any form.

The component (B) is a component to be blended as needed, and the component (B) is represented by the general formula: (ERSiO _2/2 ) (wherein E
And R are the same as above. ) Is a linear diorganopolysiloxane having a siloxane unit as a main skeleton. In the above formula, the epoxy group-containing organic group of E and the monovalent hydrocarbon group of R are the same as those mentioned above.

The component (B) is represented by the general formula:
_{R 3 SiO- (R 2 SiO)} d (ERSiO) e -SiR 3
(In the formula, R and E are the same as described above, and d and e are positive numbers.) A linear diorganopolysiloxane having an epoxy-containing organic group in a side chain, a general formula: ER
₂ SiO- (R ₂ SiO) _f —SiR ₂ E (wherein R and E are the same as above, and f is a positive number) and has an epoxy-containing organic group at both ends. Linear diorganopolysiloxane, general formula: ER ₂ SiO— (R ₂
During _{SiO) g (RESiO) h -SiR} 2 E ( wherein, R and E is as defined above, g and h are positive numbers.)
A linear diorganopolysiloxane having epoxy-containing organic groups at both ends of the molecular chain and side chains, represented by the general formula: {R ₃ SiO (R ₂ SiO) _i (ERSiO) _j } ₂
-SiR-X-SiR- {O ( R 2 SiO) k (ERSi
O) ₁ -SiR ₃ } ₂ (wherein R and E are the same as defined above, i, j, k and l are positive numbers, and X is a divalent hydrocarbon group). A linear diorganopolysiloxane having a containing organic group is exemplified. The blending amount of the component (B) is 0 to 99 parts by weight, preferably 0 to 95, relative to 100 parts by weight of the component (A).
Parts by weight.

The composition of the present invention comprises the above-mentioned component (A), component (B) and component (C) or component (A) and component (C). In addition, branched organopolysiloxanes, such as the general formula:
_{RSi- {O (R 2 SiO)} m (ERSiO) n -Si
Compounding an organopolysiloxane containing R ₃ } ₃ (wherein R and E are the same as above, and m and n are positive numbers) may be used unless the object of the present invention is impaired. .

The (C) onium salt-based photoinitiator is
Generates an acid upon irradiation, causing the ring-opening polymerization reaction of the epoxy group
It is a catalyst for rubbing, and conventionally known catalysts can be used
Is. One of such onium salt photoinitiators is
General formula; R¹ ₂I⁺X^-, R¹ ₃S⁺ X^-, R¹ ₃Se⁺X^-, R¹ _FourP
⁺X^-, R¹N₂ ⁺X^-(In the above formula, R¹Is an aryl group,
X^-Is SbF₆ ^-, AsF₆ ^-, PF₆ ^-, BF_Four ^-, HS
O_Four ^-, ClO_Four ^-Non-nucleophilic and non-basic anions such as
is there. ) Iodonium salt, sulfonium salt,
Examples include selenonium salts, phosphonium salts, and diazonium salts
Shown. The amount of component (C) is 10
The amount is 0.01 to 20 parts by weight with respect to 0 parts by weight.
The amount is preferably 0.5 to 10 parts by weight.

The ultraviolet-curable organopolysiloxane composition of the present invention has the above-mentioned components (A), (B) and (C), or (A) and (C) in a predetermined amount. It can be easily produced by mixing, but in addition to these components, if necessary, photosensitizers, reactive diluents such as epoxy functional monomers, thickeners, and improved adhesion to substrates. Agent, leveling agent, antistatic agent, defoaming agent, dye,
Addition of a pigment, an organic solvent, etc. may be carried out without impairing the object of the present invention.

The above-mentioned ultraviolet-curable organopolysiloxane composition of the present invention has the characteristic that it is rapidly cured by irradiation with ultraviolet rays to form a cured film having excellent releasability. By making the best use of it, it is preferably used as a composition for a release liner of an adhesive. As a method of using it as a composition for a release liner, for example, the composition of the present invention may be applied on the surface of paper, plastic film, metal foil or the like in an amount of 0.1 to 200 μm.
A general method is to apply a thin film of a certain degree and irradiate the applied surface with ultraviolet rays to cure it. Examples of the method of applying the composition of the present invention include a method of applying using a bar coater, a gravure coater, a reverse coater and the like, and a method of applying by spraying. A mercury arc lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, or the like can be used as the light source for irradiating the method ultraviolet rays.

[0013]

EXAMPLES The present invention will be described below with reference to examples. In addition,
In the examples, “parts” means “parts by weight”, and the viscosity is 2
It is a value measured at 5 ° C. Further, the peeling resistance value of the cured film of the ultraviolet curable organopolysiloxane composition and the residual adhesion rate of the adhesive substance were measured according to the following methods.

Measurement of Peeling Resistance Value A predetermined amount of the UV-curable organopolysiloxane composition was coated on the surface of paper and irradiated with UV rays to form a cured film. An acrylic pressure-sensitive adhesive [manufactured by Toyo Ink Co., Ltd., trade name: Olivine BPS5127] was applied on this film, and this was dried under heating at a temperature of 70 ° C. for a heating time of 2 minutes. Then, attach a piece of laminating paper to it,
With a load of 20 g / cm ² , a temperature of 25 ° C and a humidity of 60
% Condition for 24 hours. Then, using a high-speed peel tester, angle 180 at each speed of 100 m / min.
The strength required for peeling the laminated paper at that time (g
f) was measured. All sample widths were 5 cm.

Residual Adhesion Rate A predetermined amount of the ultraviolet-curable organopolysiloxane composition was applied to the surface of paper and irradiated with ultraviolet rays to form a cured film. Adhesive tape [Nitto Denko Co., Ltd.,
Product name: Knit-polyester pressure-sensitive adhesive tape 31B] was laminated and aged at 70 ° C. for 20 hours while applying a load of 20 g / cm ² . Then, the adhesive tape was peeled off, and the peeled adhesive tape was attached to a stainless steel plate to give 20 g /
A load of cm ² was applied and the mixture was left for 30 minutes at 25 ° C. Then, the pressure-sensitive adhesive tape was pulled under the conditions of an angle of 180 degrees and a speed of 0.3 m / min, and the force (gf ¹ ) required for peeling at that time was measured. Further, as a blank test, the above-mentioned adhesive tape was laminated on a Teflon (R) sheet in the same manner as above,
The force (gf ² ) required for peeling the adhesive tape was measured in the same manner as above. From these values, the residual adhesion rate (%) was calculated according to the following formula. Residual adhesion rate (%) = (gf ¹ /
gf ² ) x 100

[0016]

[Synthesis Example 1] In a 300 ml flask equipped with a stirrer,
131.5 g of 4-vinylcyclohexene oxide and 127 μl of a 10% toluene solution of platinum-1,3-dimethyl 1,1,3,3-tetravinyldisiloxane complex were added and heated to 95 ° C. with stirring. Thereto, a mixed solution of 60.0 g of tetrakis (dimethylsiloxy) silane and 6.9 g of dimethylacetoxysilane was added from a dropping funnel for 30
It dripped over minutes. Then, this reaction solution was heated at 100 ° C. for 1 hour.
The reaction was completed by stirring for a period of time. Then, after cooling to 50 ° C., 20.5 g of methanol was added, and the mixture was heated again and refluxed for 1 hour. Then, the low-boiling substance was distilled off under reduced pressure to obtain 162.3 g of a yellow liquid (reaction product). As a result of nuclear magnetic resonance spectrum analysis, this reaction product was found to be an epoxy group-containing organosilicon compound represented by the following chemical structural formula (Formula 1). The viscosity of this reaction product was 250 mPa · s. When the reaction product was analyzed by gel permeation chromatography, it did not contain a high molecular weight substance having a molecular weight of 3000 or more, which is considered to be polymerized by ring opening of the epoxy group.

[0017]

[Chemical 1]

[0018]

[Synthesis example 2] In a 200 ml flask equipped with a cooling tube and a thermometer, 20.0 g of the epoxy group-containing organosilicon compound obtained in the above synthesis example 1, 67.4 g of octamethylcyclotetrasiloxane, N, N-dimethylformamide. 4.4
g and 0.3 g of potassium hydroxide were added, and the mixture was stirred at 110 to 120 ° C. for 5 hours. Then, the mixture was cooled to room temperature, 0.73 g of acetic acid was added to neutralize the mixture, and filtration was performed. Then, low-boiling substances were distilled off under reduced pressure to give a slightly yellow liquid (reaction product) 78. 5 g was obtained. Analysis of this reaction product (polymer 1) revealed that it had an average compositional formula: (EMe ₂ SiO _1/2 ) ₄ (Me ₂ SiO _2/2 ).
₃₅ (SiO _4/2 ) _0.75 {In the formula, E is a 2- (3,4-epoxycyclohexyl) ethyl group, and Me is a methyl group. } It was the resin-like organopolysiloxane shown by these. The polystyrene-reduced number average molecular weight (Mn) of this organopolysiloxane was 3700, the viscosity was 60 mPa · s, and the epoxy equivalent was 10
It was 40.

[0019]

[Synthesis example 3] 200 ml flask equipped with a cooling tube and a thermometer
The epoxy group-containing organosilicon obtained in Synthesis Example 1 above
Compound 15.1 g, octamethylcyclotetrasiloxa
101.8 g, N, N-dimethylformamide 5.9
g, potassium hydroxide 0.35 g, 110-1
The mixture was stirred at 20 ° C for 5 hours. The mixture is then allowed to reach room temperature.
It was cooled with, neutralized with 0.73 g of acetic acid, and filtered.
After that, the low-boiling substance was distilled off under reduced pressure to give a slightly yellow liquid (reaction formation
The product) 104.2 g was obtained. This reaction product (polymer
2) was analyzed and found to have an average composition formula; (E
Me₂SiO_1/2)_Four (Me₂SiO_2/2)₇₁(SiO_4/2)
_0.67(In the formula, E is 2- (3,4-epoxycyclohexyl)
Ru) is an ethyl group and Me is a methyl group. )
It was a resin-like organopolysiloxane. Well
Also, in terms of polystyrene of this organopolysiloxane
Has a number average molecular weight (Mn) of 5,300 and a viscosity of 90.
It was mPa · s and the epoxy equivalent was 1710.

[0020]

[Synthesis Example 4] In a 300 ml flask equipped with a stirrer,
Blocking trimethylsiloxy groups at both ends with a viscosity of 60 mPa · s
Methyl hydrogen siloxane / dimethyl siloxane
163.1 g of copolymer and platinum-1,3-dimethyl 1,
10% of 1,3,3-tetravinyldisiloxane complex
Luene solution 4.7 μl, xylene 105.0 g and t
-Add 60 mg of butylpyrocatechol and stir it while stirring.
And heated to 120 ° C. 4-vinyl cyclohex
31.9 g of senoxide was added from the dropping funnel over 30 minutes
Dropped. Continuously, this reaction solution was refluxed with xylene at 2:00.
It was stirred for a while. After the reaction is complete, cool to 100 ° C. and reduce the pressure.
The low-boiling substance and xylene were distilled off with a yellow liquid (reaction product).
170.0 g of the product) was obtained. This reaction product (polymer
As a result of analysis of 3), the average composition formula: (Me₃SiO_1/2)₂  (EMeSiO_2/2)_6.8  (M
e₂SiO_2/2)_52.1 {In the formula, Me is a methyl group and E is 2- (3,4-epoxy)
Xycyclohexyl) ethyl group. },
Methyl blocked at both ends with trimethylsiloxy groups {2- (3,4
-Epoxycyclohexyl) ethyl} siloxane dime
It was a chill siloxane copolymer. In addition, this straight chain
Number average molecular weight (Mn) of the polymer in terms of polystyrene
Is 8400, the viscosity is 244 mPa · s,
The epoxy equivalent was 880.

[0021]

Example 1 Bisdodecylphenyliodonium hexafluoroantimonate (2 parts) and hexane (567 parts) were added to Polymer 1 (98 parts) obtained in Synthesis Example 2 and mixed uniformly to obtain an ultraviolet-curable organopolyene. A siloxane composition was prepared. This composition was coated on polyethylene laminated paper using a coater bar. After the hexane was dried with cold air, it was irradiated with ultraviolet rays using a conveyor type ultraviolet irradiation device (model: Fusion 120 W / cm ² ) to cure the coating film. At this time, the curability was judged by rubbing the coating film with a finger three times strongly and curing the film without smear and rub-off. The peel resistance and residual adhesion of this cured film were measured, and the results are shown in Table 1.

[0022]

Example 2 Bisdodecylphenyliodonium hexafluoroantimonate (2 parts) and hexane (567 parts) were added to Polymer 2 (98 parts) obtained in Synthesis Example 3 and mixed uniformly to prepare an ultraviolet-curable organopolyene. A siloxane composition was prepared. The properties of this composition were measured in the same manner as in Example 1 and the results are shown in Table 1.

[0023]

Example 3 Polymer 2 (10 parts) obtained in Synthesis Example 3 and polymer 3 (88 parts) obtained in Synthesis Example 4 were mixed, and bisdodecylphenyliodonium hexafluoroantimonate (2 parts) and hexane were mixed. (567 parts) was added and uniformly mixed to prepare an ultraviolet-curable organopolysiloxane composition. The characteristics of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0024]

Comparative Example 1 Polymer 3 (98 parts) obtained in Synthesis Example 4
Iodonium-based photoinitiator (2 parts), hexane (567
Part) and mixed uniformly to prepare an ultraviolet-curable organopolysiloxane composition. The characteristics of this composition were measured in the same manner as in Example 1. The results are shown in Table 1. From this result, tetrafunctional siloxane unit (Q unit)
A composition of the present invention using an epoxy functional organopolysiloxane containing (Polymer 1, Polymer 2) is
Compared to the composition of Comparative Example 1 consisting only of linear epoxy-functional organopolysiloxane (Polymer 3) without tetrafunctional siloxane units (Q units), curability despite high epoxy equivalent, It was confirmed that the residual adhesiveness was the same and the peeling property was excellent.

[0025]

[Table 1]

[0026]

The UV-curable organopolysiloxane composition of the present invention comprises a tetrafunctional siloxane unit (SiO _4/2
Since the main component is a specific epoxy-functional organopolysiloxane containing a unit, it has a feature that it can be rapidly cured by irradiation of ultraviolet rays to form a cured film having a small peeling force from an adhesive substance.

Continued front page    (72) Inventor Haruna Mizuno             2-2 Chikusaigan, Ichihara-shi, Chiba Toray Dow             Corning Silicon Co., Ltd. R & D             In headquarters (72) Inventor Makoto Yoshitake             2-2 Chikusaigan, Ichihara-shi, Chiba Toray Dow             Corning Silicon Co., Ltd. R & D             In headquarters F term (reference) 4J002 CP051 CP052 EB116 FD206                       GH01                 4J036 AK17 GA01 GA24 HA02 JA01

Claims (4)

[Claims] 1. (A) Average composition formula (1): (ER ₂ SiO _1/2 ) _a (R ₂ SiO _2/2 ) _b (SiO _4/2 ) _c (1) (wherein , E is an epoxy group-containing organic group, R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, a, b and c
Is a number of 1 or more, a / c is 3 or 4, b /
c is a number of 4 or more. ), And a resinous organopolysiloxane having a viscosity at 25 ° C. of 10 to 10,000 mPa · s (100 parts by weight), (B) Formula: (ERSiO _2/2 ) (wherein E and R are as described above). From the linear diorganopolysiloxane (0 to 99 parts by weight) having a siloxane unit as a main skeleton and the (C) onium salt photoinitiator (0.01 to 20 parts by weight). Which is a UV-curable organopolysiloxane composition. 2. The UV-curable organopolysiloxane composition according to claim 1, wherein R in the component (A) is a methyl group. 3. The ultraviolet-curable organopolysiloxane composition according to claim 1, wherein E of the component (A) is a 2- (3,4-epoxycyclohexyl) ethyl group. 4. The component (B) has the general formula: R ₃ SiO—.
A linear diorganopolysiloxane represented by (R ₂ SiO) _d (ERSiO) _e —SiR ₃ (wherein R and E are the same as defined above, and d and e are positive numbers). The ultraviolet-curable organopolysiloxane composition according to claim 1.