JPH0553183B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides an organopolysiloxane composition for release paper, in particular, which exhibits little change in release force due to changes over time.
The present invention relates to an organopolysiloxane composition for release paper that has excellent adhesion and can further change this peeling force as desired. (Prior art) Regarding organopolysiloxanes for release paper, so-called addition reaction type organopolysiloxanes consisting of alkenyl group-containing organopolysiloxanes, organohydrodiene polysiloxanes, and platinum catalysts are widely used, and these are Although it is suitable for products with relatively low peeling force, such as labels, tapes, wallpaper, and decals, there are significant restrictions on its use in fields that require large peeling force, such as engineering paper and asphalt wrapping paper. received,
There are practical difficulties. Therefore, for this type of use, products based on condensation reaction type organopolysiloxanes with various types of organic groups bonded to silicon atoms and various blending ratios of each component have been proposed, but these In addition to poor curing properties, the resulting cured film has poor residual adhesion and blocking resistance. Attempts have also been made to improve releasability by adding fillers such as ethyl cellulose, silica, etc., but these tend to cause unevenness and increased viscosity of the coating solution and have poor coating properties. Not practical. In addition, it is difficult to blend resins and fillers other than siloxane into the addition reaction type organopolysiloxane compositions described above, as in the condensation reaction type compositions, and the mixing ratio of each component constituting the composition is difficult. Also, when the radical species of organosiloxane as the main component is changed, the peeling force changes significantly over time, _making it inconvenient to _use . A method has also been proposed in which a toluene-soluble copolymer consisting of a siloxane unit represented by _SiO2 and a toluene unit is added (see JP-A-52-86985), but most of this copolymer does not harden. Therefore, there is a disadvantage that the adhesive strength and tack of the pressure-sensitive adhesive are greatly reduced. According to this method, the change in peel force over time due to bonding with adhesive can be considerably reduced, but the peel force over time of the base material itself treated with this organopolysiloxane is It has the disadvantage that it is extremely large and difficult to maintain the initial peeling force or other peeling forces. (Structure of the Invention) The present invention relates to an organopolysiloxane composition for release paper that solves the above-mentioned disadvantages. 100
Parts by weight, (2) Liquid organohydrodiene polysiloxane containing at least two hydrogen atoms directly bonded to silicon atoms (≡SiH bonds) in one molecule
0.1 to 20 parts by weight, (3) 25 to 75% by weight of a solvent-soluble polysiloxane consisting of siloxane units represented by the formula (CH ³ ) ₃ SiO _0.5 and SiO ₂ and the formula (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂
Solvent-soluble polysiloxane 75~ consisting of siloxane units denoted by ( _CH2 =CH) _SiO0.5 and _SiO5
5 to 100 parts by weight of a mixture with 25% by weight, (4) (1) to
(3) A catalyst for addition reaction in an amount of 5 to 1000 ppm based on the total amount of components. In other words, the present inventors have conducted various studies in order to develop an organosiloxane composition for release paper that shows little change in peeling force over time, has excellent adhesion, and can also change this peeling force arbitrarily. , an organosiloxane consisting of a siloxane unit represented by the formula (CH ₃ ) ₃ SiO _0.5 and a siloxane unit represented by the formula SiO ₂ in a conventionally known addition reaction type organopolysiloxane composition, and this formula (CH ₃ ) ₃ When a mixture of SiO _0.5 and an organosiloxane consisting of a siloxane unit represented by SiO ₂ and a siloxane unit represented by the formula (CH ₃ ) ₂ (CH ₂ =CH)SiO _0.5 is added, peeling occurs over time. Small force change and good adhesion.
It has been discovered that an organopolysiloxane for release paper with a good residual adhesion rate can be obtained, and that the peeling force of this organosiloxane mixture can be freely adjusted by changing the mixing ratio of two types of organosiloxanes. Check and
The present invention was completed by conducting research on the types and amounts of each component to be used. Each component constituting the organopolysiloxane for release paper of the present invention and their blending amounts will be described in detail below. The organopolysiloxane as the first component constituting the composition of the present invention is said to contain an alkenyl group bonded to a silicon atom, and from the viewpoint of curability, at least two of these alkenyl groups are present in one molecule. It must be included. In addition, since this organopolysiloxane is substantially linear, for example, the following formula R is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an aryl group such as a phenyl group or a tolyl group, a cycloalkyl group such as a cyclohexyl group, or a carbon atom of these groups. The same or different unsubstituted or substituted monovalent hydrocarbon groups in which part or all of the hydrogen atoms in the group are substituted with halogen atoms, cyano groups, etc., m,
n is assumed to be a positive number of 1 or more, but from a practical standpoint, 60 mol% of this R is often a methyl group, and this also has a viscosity at 25°C.
It is preferable to have a molecular weight of 50 cS or more, but the molecular chain terminal may be capped with a methyl group, a vinyl group, a phenyl group, a hydroxyl group, an alkoxy group, or the like. Next, the organohydrodiene polysiloxane as the second component constituting the silicone composition of the present invention may be a known organohydrodiene polysiloxane used in this type of addition reaction type silicone composition, and at least two organohydrodiene polysiloxanes are used in one molecule. It is necessary to have a hydrogen atom (≡SiH group) bonded to a silicon atom, but it is preferable that 90 mol% or more of other organic groups are methyl groups. Various conventionally known polysiloxanes can be cited as this type of polysiloxane, and regardless of whether they are linear, branched, or cyclic, they can be expressed by the following formula: A cohydrolysis condensate whose average compositional formula is [CH ₃ SiO _1.5 ] _i [H ₃ HSiO] _j [(CH ₃ ) ₃ SiO _0.5 ] _k (where a, g are integers of 2 or more, b, e, f, h
is 0 or a positive integer, c, d, i, j, k are positive integers, and g+h=3 to 8 are exemplified, but these viscosities at 25°C are several cS
It can be in a wide range from hundreds of thousands of cS to hundreds of thousands of cS.
The amount of this substance used varies slightly depending on the purpose and use of the composition of the present invention, but in general, the above-mentioned organopolysiloxane as the first component is used.
The amount may be in the range of 0.1 to 20 parts by weight per 100 parts by weight. The polysiloxane mixture as the third component constituting the composition of the present invention is composed of siloxane units represented by the formula (CH ₃ ) ₃ SiO _0.5 (hereinafter abbreviated as M units) and siloxane units represented by the formula SiO ₂ (hereinafter abbreviated as M units). (hereinafter referred to as Q units), a solvent-soluble polysiloxane A consisting of these M units, Q units, and the formula (CH ₃ ) ₂
It is said to be a mixture with solvent-soluble polysiloxane B consisting of siloxane units (hereinafter abbreviated as dimethylvinyl units) represented by (CH ₂ = CH) SiO _0.5 , but this polysiloxane A consists of M units and Q units. The molar ratio of M units is in the range of 1Q unit = 0.65 to 1.3, and the content of hydroxyl groups bonded to silicon atoms is 6.
This polysiloxane B has a molar ratio of M units, dimethylvinyl units, and Q units equal to or less than M/Q in polysiloxane A.
Similarly, M units + dimethylvinyl units / Q units = 0.65 to 1.3, and the amount of hydroxyl groups bonded to silicon atoms can also be 6% by weight or less, similar to polysiloxane A. Good, but this one has a vinyl group content of 0.05 to 0.15 mol/
It is best to use 100g. In addition, the mixing ratio of polysiloxane A and polysiloxane B constituting this mixture is such that if the amount of polysiloxane A is less than 25% by weight, the stability over time of the peeling force of the film obtained from this composition will deteriorate. Polysiloxane A25 to 75% by weight, Polysiloxane B75 as the adhesion of this cured film deteriorates if it exceeds 25% by weight.
~25% by weight is required. Note that if the amount of the mixture of polysiloxane A and polysiloxane B used is 5 parts by weight or less based on 100 parts by weight of the organopolysiloxane as the first component, the effect of controlling the release force in this composition can be improved. If the amount is 100 parts by weight or more, the curability produced from this composition will be impaired, so the amount must be in the range of 5 to 100 parts by weight.
This preferred range is 10 to 50 parts by weight. The addition reaction catalyst as the fourth component constituting the composition of the present invention may be any known catalyst, and examples thereof include platinum black, chloroplatinic acid, complex salts of chloroplatinic acid and various olefins and vinylsiloxanes, Examples include chloroplatinic acid-alcohol coordination compounds, rhodium, rhodium-olefin complex salts, etc., and the amount of these added is approximately 5 to 1000 ppm of platinum or rhodium (based on the total amount of the first to third components). The weight ratio may be adjusted within this range depending on the reactivity of the first to third components and the desired curing speed. The composition of the present invention can be obtained by uniformly mixing predetermined amounts of the first to fourth components described above. It is optional to add activity inhibitors such as various organic nitrogen compounds, organic phosphorus compounds, acetylene compounds, oxime compounds, and organic chromium compounds as necessary, and inorganic fillers such as silica and pigments. It is also optional to do so. The thus obtained composition of the present invention can be used as it is, or after diluting it with an appropriate organic solvent such as toluene, xylene, hexane, methyl ethyl ketone, etc., using a roll coater or reverse coating. Apply to the base material using a coater, gravure coater, etc., and
By heating for 60 seconds, it is possible to provide a cured film having the desired peeling force, residual adhesive strength, etc. on the surface of the substrate, but the coating amount is approximately 0.2 to 2.0 g/m ² in terms of siloxane. It may be within the range of . (Effects) The composition of the present invention is said to be useful for producing release paper, and this composition is applied to the surface of paper, plastic paper, etc. as a base material for producing release paper, and is heated and cured to form the base material. When a cured film is formed on the surface, this cured film exhibits excellent releasability, but this releasability does not change over time, and its adhesion and residual adhesive strength are also excellent. By changing the mixing ratio of polysiloxane A and polysiloxane B in the third component, the release force can be freely adjusted, which has the advantage that a release paper with a desired release force can be easily obtained. Therefore, it is useful as a material that imparts releasability to processing paper, asphalt wrapping paper, etc., which have been difficult to treat with conventional products. (Example) Next, examples of the present invention will be given. Parts in the examples are parts by weight, and viscosity is the measured value at 25°C. The ratio and adhesion are the results measured by the following method. () Peeling Resistance-1 Initial Peeling Force A predetermined amount of the composition is applied to the surface of a thin film or sheet base material, and heated for a predetermined time in a hot air circulation dryer maintained at a predetermined temperature to form a cured film. After leaving this in a room at 25℃ for 24 hours, apply an acrylic solvent-based adhesive, Olivine BPS, to the cured film surface.
-5127 [trade name manufactured by Toyo Ink Mfg. Co., Ltd.] using an applicator to a wet thickness of 130 μm.
Apply it evenly so that it has a thickness of 64 mm, heat treat it at 100℃ for 3 minutes, and then apply a weight of 64 mm to the treated surface.
After g/ ^m2 high-quality paper is laminated and left in a room at 25℃, the laminated paper is pulled at a peeling speed of 0.3 m/min at an angle of 180° using a tensile testing machine to determine the force required for peeling. (g) was measured and used as the initial peeling force. -2 Silicone release paper Aging peel resistance The base material on which the cured film has been formed is allowed to age by leaving it at room temperature or in a constant temperature bath at 50℃ for a predetermined period of time, then apply the same adhesive as in -1 above to the surface of this film. Then, the same treatment as in -1 above was carried out, and the force required for peeling was measured, which was determined as aging peel resistance of the silicone release paper. () Residual adhesion The substrate on which the cured film has been formed is heated to room temperature of 25℃ for 24 hours.
After leaving it for a while, affix Nitto Polyester Tape No. 31B (trade name manufactured by Nitto Electric Industry Co., Ltd.) to this film surface and apply it in an atmosphere of 70℃.
After aging for 20 hours under a load of 20 g/cm ² , the tape was peeled off and applied to a stainless steel plate. A tape roller weighing 2 kg was made to reciprocate once on this plate, and the tape was left in a room at 25°C for 30 minutes. Thereafter, the peeling force was measured using the same method as in method-1 above. In addition, the same Nittsu polyester tape No. 31B as above was adhered to a Teflon plate, and it was treated in the same manner as above to establish the peeling force of this material, and this was used as a blank value. The force ratio was expressed as a percentage, and this was taken as the residual adhesive strength. () Adhesion After applying a predetermined amount of the composition prepared in each example to polyethylene laminate paper, heat treatment was performed at 100°C for a predetermined time (seconds) to form a hardened film, and then this film was rubbed with a finger. The state of the silicone film was observed, and the adhesion was determined based on the following criteria. 〇...No falling off or clouding occurs, △...No falling off but clouding occurs, ×... Falling off. Examples 1 to 3, Comparative Examples 1 to 7 Vinyl group content is 1.5 mol%, viscosity is
To 30 parts of methyl vinyl polysiloxane of 10000000 cS, 0.5 part of methylhydrodiene polysiloxane with a viscosity of 20 cS and 4-methyl-1-butyne-
Composition A was prepared by uniformly dissolving 0.5 parts of 3-ol in 69 parts of toluene.
Sample 1 was prepared by uniformly dissolving 10 parts of A in 50 parts of toluene. Also, M units where M units/Q units (molar ratio) = 0.7
A toluene-soluble polysiloxane consisting of units and Q units, M units + dimethyl vinyl units/Q units (mole ratio) = 1.2, and the vinyl group content is 0.1 mol/100
A 30% toluene solution was prepared by mixing g of toluene-soluble polysiloxane consisting of M units, dimethylvinyl units, and Q units at a weight ratio of 1:1, and the mixture was added to 1 part per 10 parts of the above composition A. ,
Added 1.5 parts, 2 parts, toluene 49 parts, 48.5 parts, 48
Samples 2, 3, and 4 were prepared by uniformly dissolving the mixture in the following parts. Next, chloroplatinic acid-olefin complex salt was added to these samples 1 to 4 in an amount of 20 ppm of platinum, and the mixture was stirred and mixed until homogeneous to prepare treatment solutions 1 to 4. Next, these treatment solutions 1 to 4 are applied to high-quality paper laminated with polyethylene at a concentration of 0.8 g/m ² (solid content), and heated at 100°C for 30 seconds to form a cured film. When the physical properties of the film were examined using the method described above, the results shown in Table 1 were obtained. On the other hand, for comparison, the polysiloxane mixture used above was mixed with M units/Q units (molar ratio) =
A toluene-soluble polysiloxane consisting of M units and Q units of 0.7 was added to 10 parts of the composition A obtained above at 1 part, 1.5 parts, and 2 parts to produce 49 parts, 48.5 parts, and 48 parts of toluene. Samples 5, 6, and 7 were prepared by uniformly dissolving chlorinated platinic acid-olefin complex salt in an amount of 20 ppm of platinum, and the mixture was stirred and mixed until the mixture became uniform to prepare processing solutions 5 to 7. When the physical properties of the cured film obtained by the same treatment were examined, the results shown in Table 1 were obtained. In addition, for comparison, the polysiloxane mixture used above was prepared using a toluene-soluble siloxane consisting of M units, dimethyl vinyl units, and Q units, where M units + dimethyl vinyl units/Q units (molar ratio) = 1.2. Samples 8 to 11 and treatment liquids 8 to 11 were prepared using polysiloxane and treated in the same manner as in the above comparative example.
When the physical properties of the film obtained using the same were investigated, the results shown in Table 1 were obtained.

[Table] Examples 4 to 6, Comparative Examples 8 to 9 60 parts of methylvinyl polysiloxane with a viscosity of 100 cS, in which both ends of the molecular chain are blocked with dimethylvinylsilyl groups, was added at a ratio of M units/Q units (molar ratio) of 0.7. Some M
After mixing 80 parts of a 50% toluene solution of polysiloxane consisting of units and Q units, the toluene was distilled off under reduced pressure, and 7 parts of methylhydrodiene polysiloxane with a viscosity of 20 cS and 3-methyl-1-butyne were mixed. Composition B was prepared by uniformly mixing 1 part of -3-ol.
I made it. In addition, the above-mentioned methylvinylpolysiloxane 60
part, M unit + dimethylvinyl unit / Q unit (mole ratio) = 1.2, vinyl group content is 0.10 mol / 100g
After mixing a 50% toluene solution of polysiloxane consisting of M units, dimethyl vinyl units, and Q units, the toluene was distilled off under reduced pressure, and 7 parts of methylhydrodiene polysiloxane with a viscosity of 20 cS and 3 Composition C was prepared by uniformly mixing 1 part of -methyl-1-butyn-3-ol. Then, this composition B and composition C were mixed at 100/0,
Sample 11 was prepared by adding 20 ppm of platinum of chloroplatinic acid-olefin complex salt to 10 parts of a mixture of weight ratios of 75/25, 50/50, 10/90, and 0/100 and stirring until uniform. , 12, 13, 14, and 15 were made. Next, these samples were placed on glassine paper at 1.5 g/m ²
(solid content) at 110℃ or 170℃.
A cured film was formed by heat treatment at ℃ for 1 minute, and its physical properties were examined using the method described above.
The results shown in Table 2 were obtained.

【table】

Claims (1)

[Scope of Claims] 1 (1) 100 parts by weight of an alkenyl group-containing diorganopolysilosane having at least two alkenyl groups directly bonded to silicon atoms in one molecule; Liquid organohydrodiene polysiloxane containing at least two directly bonded hydrogen atoms (≡SiH bonds)
0.1-20 parts by weight, (3) Solvent-soluble polysilosane 25-25 consisting of siloxane units represented by the formula (CH ₃ ) ₃ SiO _0.5 and SiO ₂
75% by weight and the formula (CH ₃ ) ₃ SiO _0.5 , (CH ₃ ) ₂ (CH ₂
=CH) Solvent-soluble polysiloxane 75~ consisting of siloxane units denoted by SiO _0.5 and SiO ₂
Mixture with 25% by weight 5-100 parts by weight, (4) 5-1000 ppm based on the total amount of components (1) to (3) above
An organopolysiloxane composition for release paper, comprising: an addition reaction catalyst;