JPH027989B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a silicone composition for mold release, and particularly to a silicone composition for mold release that has easy peeling at low speeds and has a small tendency for the peeling force to increase even when the peeling speed increases. be. (Prior art) In order to prevent adhesion or adhesion between a base material such as paper, processed paper, or plastic film and an adhesive substance, a silicone film is formed on the surface of the base material to impart release properties. It is well known that the releasability of this silicone film varies greatly depending on the type of base material and the type of adhesive substance that is bonded to the silicone film, and that The force required for peeling (hereinafter referred to as peeling force) varies greatly depending on the peeling speed (hereinafter referred to as peeling speed), and generally the peeling force increases as the peeling speed increases. This increase in peel force is caused by a peel rate of 0.1
The smaller the peeling force at a low speed of ~10 m/min, the more significant it tends to be when the peeling speed is increased to a high speed of 30 to 300 m/min.
Although it is desirable for silicone compositions for mold release to have as small a peeling force as possible at both low and high peeling speeds, currently the peeling force at low peeling speeds is small but at high peeling speeds. These are either those with a high peeling force or those with a high peeling force at low peeling speeds and low peeling forces at high peeling speeds. (Structure of the Invention) The present invention relates to a silicone composition for mold release that solves these disadvantages and has a low peeling force at low peeling speeds and a relatively small peeling force at high peeling speeds. formula

[Formula] (where R ¹ is a monovalent aliphatic unsaturated hydrocarbon group, R ² is the same or different unsubstituted or substituted monovalent hydrocarbon group, a and b are positive numbers, and a
+b≦3) Organopolysiloxane
100 parts by weight, b) General formula

[Formula] (where R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group, c and d are positive numbers, and c+d≦3) organohydrodiene polysiloxane
0.1 to 10 parts by _weight , c) General formula (SiO ₂ ) _e (R ⁴ ₂ SiO) _f (R ⁴ R ⁵ SiO) _g (R ⁴ SiO _1.5 ) _h [Here, R ⁴ is the same or different An unsubstituted or substituted monovalent hydrocarbon group, R ⁵ is a polyoxyalkylene group of the formula -(CH ₂ ) _o O (C ₂ H ₄ O) _i (C ₃ H ₆ O) _j -R ⁶ (R ⁶ is hydrogen atom or monovalent organic group), e is 0-5, f is 0-200, g is 1-10, h is 1-20, i is 1-50, j is 0-50,
n is a positive number of 0 to 5] 0.1 to 10 parts by weight of an organopolysiloxane containing 3 to 50% by weight of a polyoxyalkylene group per molecule, and d) 0.001 to 1.0 parts by weight of platinum or a platinum compound. It is characterized by: To explain this, the present inventors have conducted various studies on obtaining a silicone composition for mold release in which the peeling force does not increase particularly even when the peeling speed is high, and as a result, the silicone composition for mold release is known as a silicone composition for mold release. An organosiloxane containing (R ⁴ SiO _{1 .5} ) units and a polyoxyalkylene group in the molecule in a so-called addition reaction type organosiloxane composition consisting of a vinyl group-containing siloxane, an organohydrodiene polysiloxane, and a platinum catalyst. It was discovered that the addition of organic siloxane can reduce the peeling force under high-speed peeling, and the present invention was completed by conducting research on the type and amount of organosiloxane to be added. The organopolysiloxane as component a) constituting the composition of the present invention has the general formula

[Formula], R ¹ is an aliphatic monovalent unsaturated hydrocarbon group such as a vinyl group, allyl group, or ethynyl group; R ² is an alkyl group such as a methyl group, ethyl group, propyl group, or butyl group; Cycloalkyl groups such as cyclohexyl groups, aryl groups such as phenyl, biphenyl, and naphthyl groups, alkaryl groups such as tolyl, xylyl, and ethyl phenyl groups, or some or all of the hydrogen atoms bonded to the carbon atoms of these groups. The same or different unsubstituted or substituted monovalent carbide selected from chloromethyl group substituted with halogen atom or cyano group, fluoromethyl group, 3,3,3-trifluoropropyl group, monochlorophenyl group, cyanomethyl group, etc. Hydrogen, a, and b are all positive numbers with a+b≦3, but there are no particular restrictions on the molecular structure of these molecules, which may be linear, branched, or partially cross-linked. It may be any of these or a mixture thereof. However, it is necessary that the molecule contains an aliphatic monounsaturated hydrocarbon group represented by ^R1 , and if this content is less than 0.05 mol%, the composition will have a slow curing speed. If it exceeds 15 mol%, the mold releasability will decrease, so 0.05 to 15 mol%
The unsaturated group is preferably in the range of 0.2 to 5.0 mol %, but this unsaturated group does not necessarily have to be at the end of the molecular chain. Furthermore, although there is no particular limit to the viscosity of this organopolysiloxane, since this composition is usually applied to a substrate as a diluted solution in a solvent, it is important to maintain good adhesion to the substrate and prevent repellency during coating. For this reason, it is desirable that the measured value at 25°C be 1000 centipoise or higher. Furthermore, the organohydride diene polysiloxane as component (b) constituting the composition of the present invention has the general formula

[Formula], R ³ is the same monovalent hydrocarbon group as R ² described above, c and d are both positive numbers, and c+d≦3, but there are no restrictions on the molecular structure. , linear, branched, cyclic, or partially cross-linked, or a mixture thereof. Next, the organopolysiloxane as the c) component constituting this composition is considered to be an essential component to achieve the object of the present invention, and it has the general formula (SiO ₂ ) _e (R ⁴ ₂ SiO) _f (R ₄ R ₅ SiO) _g (R ⁴ _{SiO 1.5} ) _h
R ⁴ is the same monovalent hydrocarbon group as R ² described above, and R ₅ is the formula -(CH ₂ ) _o O (C ₂ H ₄ O) _i (C ₃ H ₆ O) _j -R ⁶ , R ⁶ represents a hydrogen atom or a monovalent organic group,
Examples of this organic group include lower alkyl groups such as methyl group, ethyl group, propyl group, butyl group, and 2-ethylhexyl group, and acyl groups such as acetyl group and benzoyl group, where e is 0 to 5, and f is 0. ~
200, g is 1-10, h is 1-20, i is 1-50, j
is a positive number from 0 to 50, and n is a positive number from 0 to 5. In addition, this organosiloxane has a formula in its molecule.
If it does not contain _the siloxy group represented by R ⁴ SiO _1.5 , the peelability of the silicone film obtained from this composition will be high under high-speed peeling.
The adhesion between the silicone film and the base material also becomes poor, and the film tends to fall off from the base material. Also, this means that the polyoxyalkylene group present in this molecule is 3
If it is less than 50% by weight, the effect of reducing the peeling force under high-speed peeling of the silicone film obtained from this composition will be insufficient, and if it is more than 50% by weight, the adhesion between the silicone film and the base material will be poor, and the film will become a base material. Since it becomes easy to fall off from the material, it is necessary to contain the above-mentioned polyoxyalkylene group in an amount of 3 to 50% by weight. In addition, the platinum or platinum compound as the component (d) constituting the composition of the present invention is the above-mentioned (a) and (b).
It is a known catalyst component for addition reaction of components, and includes solid platinum supported on a carrier such as platinum black, alumina, or silica, chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid and olefin. Examples include a complex with chloroplatinic acid and a reaction product between chloroplatinic acid and an organosiloxane containing an unsaturated group. The composition of the present invention can be obtained by mixing predetermined amounts of the above-mentioned components (a) to (d), and the mixing ratio of these components is determined by If the molar ratio between the aliphatic unsaturated group bonded to an elementary atom and the hydrogen atom bonded to a silicon atom in component (b) is less than 0.2 or more than 20, the silicone component that does not participate in the reaction in these addition reactions will be excessive. Since this will hinder the curing reaction, the amount of component b) should be 0.2 to 20% per mole of component a).
It is preferable to set the amount in a mole range, preferably in a range of 0.5 to 5 moles. In addition, if component c) is less than 0.1% by weight of component a), the effect of adding it will be insufficient, and if it is more than 10% by weight, it will improve the curability of this composition, the adhesion to the substrate, and the residual adhesion of the silicone film to be made. 0.1 to 10 as the performance decreases.
in the range of % by weight, preferably in the range of 0.5 to 5.0;
If the component (d) is less than 0.001% by weight of the component (a), the catalytic effect will be insufficient, and if it is added more than 1.0% by weight, the catalytic effect will remain almost constant, which is economically disadvantageous. It may be a range. Furthermore, if necessary, an activity inhibitor may be added to this composition for the purpose of extending the pot life and suppressing the activation of platinum at room temperature. is exemplified. Further, this composition may be used after being diluted with an organic solvent if necessary, and examples of the organic solvent include toluene, xylene, trichloroethylene, perchloroethylene, hexane, ethyl acetate, and methyl ethyl ketone. The silicone composition of the present invention is said to be particularly useful as a release agent for release paper, and examples of base materials include kraft paper, polyethylene laminate paper, glassine paper, various other processed papers, and various plastic films. However, this composition may be applied to these substrates by a known method such as a roll coater, gravure coater, offset coater, or air coater, and the coating film thus obtained is coated at a temperature of 80°C or higher, preferably Heat treatment at 100° C. or higher for 10 seconds or more, preferably 20 seconds or more, provides a cured coating with excellent mold release properties, and this coating is particularly useful in that the peeling force does not increase even in high-speed peeling. Next, examples of the present invention will be given. Parts in the examples are parts by weight, viscosity is the value measured at 25°C, and the physical property values in the examples are the values measured by the following method. This is what is shown. (Peeling force) The silicone composition was applied to high-quality paper laminated with polyethylene using an offset coater to give a peel strength of 0.8
g/ ^m2 , heat cured for 20 seconds in a hot air circulation dryer at 150°C to form a silicone film, and left to stand at 25°C for 1 day.
This is an acrylic solvent-based adhesive, Olivine.
BPS-8170 [trade name manufactured by Toyo Ink Co., Ltd.] in solid content
After applying the coating at a density of 50g/ ^m2 and drying it at 100℃ for 3 minutes, it was pasted on a high-quality surface paper, pressed with a 2kg rubber roll once, and left at 25℃ for 1 day to form a 5cm wide sheet. A test piece was prepared, and the peeling force was measured when the surface paper was peeled off using a tensile tester (Shimadzu Autograph and Toyo Seiki High Speed Peeling Tester) at a peeling angle of 180°C and a peeling speed of 0.3, 60, and 180 m/min. . (Curability, adhesion) The heat curing conditions during the formation of the silicone film above were set to 100°C for 30 seconds, and the curability was judged by the presence or absence of clouding when the obtained silicone film was strongly rubbed with a finger 5 times. The adhesion was judged by whether or not the silicone film fell off at this time. (Residual adhesion rate) A commercially available kraft tape was pasted on the silicone-treated paper obtained using the peel force test method, and the adhesive was pressed at 70℃ for 20 hours under a load of 20g/ ^cm2 , and the standard adhesive strength was measured. In order to do this, a similar craft tape was attached to a Teflon plate and subjected to the same pressure bonding process, and the adhesive strength of each sample after this pressure bonding process was measured. The residual adhesion rate (%) of the sample was determined as follows. Examples 1 to 5, Comparative Examples 1 to 6 To 100 parts of dimethylpolysiloxane containing 1 mol% of vinyl groups and having a viscosity of 3000 centipoise (hereinafter abbreviated as CP), 1.0 parts of methylhydrodiene polysiloxane having a viscosity of 180CP was added. 1.0 part of polyoxyalkylene group-containing organosiloxane as shown in Table 1 and 1.0 part of a complex of chloroplatinic acid and vinylsiloxane (0.002 part of platinum equivalent) were added and stirred uniformly to form a silicone treatment bath. I made it. Next, this treatment solution was applied uniformly to high-quality paper laminated with polyethylene using an offset roll so that the amount of silicone was 0.8 g/ ^m2 , and the physical properties of the resulting silicone coating film were examined. The results shown in Table 2 were obtained. In addition, for comparison, one in which no polyoxyalkylene group-containing siloxane was added (Comparative Example 1), and one in which the polyoxyalkylene group-containing siloxane was contained in an amount of 53% by weight ( Comparative Example 2), Polyoxyalkylene group does not contain trifunctional siloxane group (Comparative Example 3), Polyoxyalkylene group content is 2% by weight (Comparative Example 4), Polyoxyalkylene One that does not contain any groups (Comparative Example 5), and one that does not contain any polyoxyalkylene group-containing siloxane, and 0.3
When we examined the physical properties of silicone films obtained from these compositions (Comparative Example 6) whose ingredients were adjusted so that the peeling force in m/min was the same as that of Example 1, we found that the second The results shown in the table were obtained.

【table】

【table】

【table】

Claims (1)

[Claims] 1 A General formula [Formula] (where R ¹ is a monovalent aliphatic unsaturated hydrocarbon group, R ² is the same or different unsubstituted or substituted monovalent hydrocarbon group, a, b is a positive number and a+b≦3)
100 parts by weight of organopolysiloxane represented by general formula [formula] (where R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group, c and d are positive numbers,
≦3) Organohydrodiene polysiloxane 0.1 to 10 parts by weight C General formula (SiO ₂ ) _e (R ⁴ ₂ SiO) _f (R ⁴ R ⁵ SiO) _g (R ⁴ SiO ₁ . ₅ )
_h [where R ⁴ is the same or different unsubstituted or substituted monovalent hydrocarbon group, R ⁵ is the formula -(CH ₂ ) _o O (C ₂ H ₄ O) _i (C ₃ H ₆ O) _j -R Polyoxyalkylene group represented by ⁶ (R ⁶ is a hydrogen atom or a monovalent organic group), e is 0 to 5, f
is 0-200, g is 1-10, h is 1-20, i is 1
~50, j is a positive number of 1 to 50, and n is a positive number of 0 to 5], containing 3 to 3 polyoxyalkylene groups in one molecule.
A mold release silicone composition comprising: 0.1 to 10 parts by weight of an organopolysiloxane containing 50% by weight; and 0.001 to 1.0 parts by weight of platinum or a platinum compound.