JPH0319268B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides a silicone composition for release paper, which can be applied to the surfaces of paper, laminated paper, plastic film, metal foil, etc. without containing an organic solvent, and can be applied to the surfaces of paper, laminated paper, plastic film, metal foil, etc. The present invention relates to a silicone composition for release paper, which can be made sticky and have excellent release properties and slip properties. (Prior art) To prevent adhesion or adhesion between a base material such as paper or plastic film and an adhesive substance, or between paper and paper, between paper and plastic film, between plastic films, or between paper or plastic film and humans. Regarding silicone compositions for mold release, which are used to impart slipperiness between hands and hands, various types of silicone compositions based on organosiloxane solutions in organic solvents or aqueous emulsions have been proposed (Japanese Patent Publication No. 1973- No. 13709, Special Publication No. 36-1397,
(See Special Publication No. 46-26798). However, for this organic solvent solution type, various proposals have been made regarding its siloxane composition, additives, promoters, etc. in order to obtain excellent mold release properties, slip properties, wear resistance, and hardening properties. However, since the organopolysiloxane used here is rubber-like with a high molecular weight, a large amount of solvent is required for its use, which has the disadvantage of causing air pollution. In addition, there is the problem that it requires a large amount of money to recover this solvent, and although water-based emulsion type products have fewer pollution problems due to the use of solvents, there are concerns about secondary pollution due to the use of emulsifiers, and there is a problem with film formation. In addition to requiring heating at high temperatures for long periods of time, it is also difficult to use organopolysiloxanes with a high degree of polymerization as the main ingredient, so coatings with excellent physical properties and slipperiness are difficult to use. The disadvantage is that a film cannot be obtained. Therefore, the silicone composition for mold release must be a solvent-free type that does not contain organic solvents or water; A composition comprising an organohydrodiene polysiloxane having hydrogen atoms bonded to silicon atoms, c) a platinum-based catalyst, and d) an activity inhibitor has also been proposed (Japanese Patent Publication No. 52-47485
However, because the vinyl siloxane as its main component has a low degree of polymerization, the film obtained from this composition has poor physical properties such as mechanical strength and lacks slipperiness. , so there is a disadvantage that its use is limited. In other words, when this composition is used as a mold release agent for craft tape, the coating film has poor slip properties, so when it is actually pasted onto cardboard etc. by hand, the work is not smooth and the friction between the hands becomes significant. The pressure-sensitive adhesive may not stick to the cardboard completely and peel off due to insufficient pressure on the tape. Furthermore, when paper or plastic film treated with this process is used as a cassette tape mount, the slipperiness is poor, causing damage to the tape and the tape not rotating smoothly. Also, after coating this on paper or plastic film,
When curing and then winding onto a metal or plastic roll to produce release paper, this film has poor slip properties, so winding onto the roll cannot be done smoothly, causing damage to the silicone-treated surface. There is also the problem that variations in mold releasability occur depending on the conditions. Therefore, attempts have been made to add slipperiness imparting agents such as dimethylsiloxane oil, polyether modified oil, surfactants, wax, and metal soap to this type of solvent-free silicone mold release agent. However, most of these silicones have poor compatibility, resulting in unstable liquids and poor curing of the silicone.
Furthermore, since these particles migrate onto the cured silicone film, when an adhesive is applied thereon, they migrate to the surface of the adhesive and deteriorate its adhesion. (Structure of the Invention) The present invention relates to a solvent-free silicone composition for release paper that solves the above disadvantages.
1) vinyl groups bonded to at least two silicon atoms in one molecule (at least one of them
), the vinyl group accounts for 0.5 to 10.0 mol% of the total organic groups, and the viscosity at 25℃ is
100 parts by weight of a substantially linear organopolysiloxane having a viscosity of 50 to 10,000 cps; 2) a substantially linear organopolysiloxane having a hydroxyl group bonded to a silicon atom at the end of the molecular chain and having a viscosity of 100,000 cps or more at 25°C; 0.5 to 40 parts by weight of organopolysiloxane with a similar structure, 3) 1
Organohydrodiene polysiloxane containing at least two silicon-bonded hydrogen atoms in the molecule, 0.5 to 50 parts by weight, and 4) a catalytic amount of a platinum-based compound, substantially free of organic solvents25 It is characterized by a viscosity of 50 to 10,000 cps at °C. That is, as a result of various studies on silicone compositions for release paper that can impart excellent release properties and slip properties to paper, plastic films, etc., the present invention has developed a silicone composition for release paper that can impart excellent release properties and slip properties to paper, plastic films, etc. When an organosiloxane with a high degree of polymerization in which both ends of the molecular chain are blocked with hydroxyl groups is added to an addition reaction type composition consisting of a platinum-based catalyst, a reaction occurs between the vinyl group-containing siloxane with a low degree of polymerization and the organohydrodiene polysiloxane. The hardened network is well intertwined with the hardened network due to the reaction between the hydroxyl groups of the organosiloxane with a high degree of polymerization and the hydrogen atoms bonded to the silicon atoms (≡SiH bonds) of the organohydrodiene polysiloxane, resulting in slipping properties. In this case, it is possible to obtain a film with excellent mechanical properties and excellent mold releasability without migration. It was discovered that this slipperiness could not be achieved unless these components were combined with each other, and the present invention was completed by conducting research on the types and amounts of each of these components. The organopolysiloxane as the first component constituting the silicone composition of the present invention is of the so-called addition reaction type, which is caused by the reaction between a vinyl group and a hydrogen atom bonded to a silicon atom. It must have at least two vinyl groups bonded to silicon atoms in the molecule, and at least one of these vinyl groups
As mentioned above, it is necessary that the compound be bonded to the side chain of the polysiloxane. Since this organopolysiloxane is substantially linear,
This is the following formula R is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an alkenyl group such as a vinyl group or an allyl group, an aryl group such as a phenyl group or a tolyl group, a cycloalkyl group such as a cyclohexyl group, Or the same or different unsubstituted or substituted monovalent hydrocarbon groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc., where m and n are 1
Although the above is a positive number, from a practical standpoint, it is preferable that 80 mol% of R be a methyl group. Also, this product has a vinyl group contained therein.
If it is less than 0.5 mol, the curability will be poor, and if it is more than 10 mol%, the peel resistance of the cured film obtained from this composition will increase, making the adhesion with the adhesive unstable in practical use, so 0.5 to 10 mol%. This should preferably be in the range of 1.0 to 8.0 mol%.
Furthermore, in order to discover the effects of the present invention, the amount of vinyl groups bonded to the side chains of the polysiloxane should be greater than the amount of vinyl groups bonded to the ends. Good. This polysiloxane must have a low degree of polymerization, so it must have a low viscosity, but if it exceeds 10,000 cps, the effect of adding the second component will be lost, so this polysiloxane must have a viscosity of 50 to 10,000 cps. should be in the range of , preferably 100 to
It is said to be 8000cps. Next, the organopolysiloxane as the second component constituting this silicone composition has hydroxyl groups (≡SiOH groups) bonded to silicon atoms at both ends of the molecular chain.
It has a high degree of polymerization with a viscosity of 100,000 cps or more at 25°C. This means that the end of the molecular chain is ≡
Groups other than SiOH, such as trimethylsilyl

[Formula] Dimethylvinylsilyl group

【formula】 trivinylsilyl group

[Formula] Methylphenylvinylsilyl group

[Curability]

After applying a predetermined amount of the composition to the surface of a thin film or sheet-like base material, it is heated for a predetermined time in a hot air circulation drying oven at a predetermined temperature, and the resulting coating film is rubbed with a finger to remove it. and determine cloudiness. [Peel resistance] A predetermined amount of the composition is applied to the surface of a thin film or sheet-like base material, and a cured film is formed by heating for a predetermined time in a hot air circulation dryer maintained at a predetermined temperature. , the effect film surface is coated with an acrylic solvent-based adhesive Olivine BPS-5127 (product name manufactured by Toyo Ink Manufacturing Co., Ltd.), an acrylic emulsion-type adhesive Olivine BPW-3110H (product name manufactured by Toyo Ink Seizo Co., Ltd.), or a rubber-based adhesive. 100% by applying solvent-based adhesive Olivine BPS-2411 (trade name manufactured by the company)
Heat-treated at ℃ for 3 minutes, then laminated paper with a basis weight of 40 g/m ² was attached to this treated surface.
After aging at 25℃ under a load of cm ² for a specified period of time, cut into 5cm widths to make test pieces. Using a tensile tester, peel at an angle of 180° at a peel rate of 0.3m/min, 30m/min.
60 m/min and measure the force (g) required for peeling. [Slip property] After forming a cured film of the composition on the surface of the sheet-like base material in the same manner as in the peel resistance test, urethane rubber or styrene-butadiene rubber with a load of 200 g was placed on the surface, and this was Pull it parallel to the silicone surface at 0.3 m/min, measure the force (g) required, and calculate the force required for pulling / 200 as the coefficient of dynamic friction (ASTMD1894-
63). In addition, regarding this slippage, the relative slipperiness was determined by moving a hand over the surface of the cured film, and this was determined based on the following criteria. ◎...Extremely good, 〇...Good sliding, ×...No slipping, XX...no slipping at all. [Residual adhesion rate] After forming a cured film of the composition on the surface of the sheet-like base material using the same method as the peel resistance test, polyester tape Lumirror 31B [trade name manufactured by Nitto Electric Industry Co., Ltd.] was applied to the surface. After applying a load of 20 g/cm ² and heating at 70°C for 2 hours, the tape was peeled off and pasted on a stainless steel plate, and then this tape was peeled off at an angle of 180° and at a peeling speed of 300 mm/min. Measure the force (g) required to peel the untreated standard tape from the stainless steel plate, and measure the force (g) required to peel the untreated standard tape from the stainless steel plate. Expressed as a percentage of Example 1, Comparative Examples 1 to 5 Both ends of the molecular chain are blocked with dimethylvinylsilyl groups, and 6 vinyl groups are bonded to the side chain of polysiloxane. The vinyl group content is 4.0 mol% and the viscosity is 600 cps. 100 parts of a copolymer of dimethylsiloxane and methylvinylsiloxane, both ends of the molecular chain are blocked with dimethylhydroxysilyl groups,
5 parts of raw rubber-like dimethylpolysiloxane with a viscosity of 4,000,000 cps, both ends of the molecular chain are blocked with trimethylsilyl groups,

[Formula] 6 parts of methylhydrodiene polysiloxane with a unit of 90 mol% and a viscosity of 100 cps and the formula

Silicone composition A was prepared by adding 2 parts of a complex salt of platinum and vinylsiloxane (200 ppm in terms of platinum) to a mixture of 1 part of 3-methyl-1-butyne represented by the formula and stirring uniformly. I made it. For comparison, both ends of the molecular chain were blocked with dimethylhydroxysilyl groups instead of raw rubber dimethylpolysiloxane in the above, but the viscosity was
Adding 5 parts of dimethylpolysiloxane of 1000 cps, the silicone composition B was made into a viscosity in which both ends of the molecular chain were blocked with dimethylhydroxysilyl groups.
4000000 cps but containing 4.0 mol% of vinyl groups as 5 parts of silicone composition C
This dimethylpolysiloxane was converted into raw rubber-like methylvinylsiloxane with a viscosity of 4,000,000 cps containing 0.5 mol% of vinyl groups with both ends of the molecular chain capped with dimethylvinylsilyl groups, and 5 parts of this was added to form silicone composition D. , silicone composition E was prepared by converting this into 5 parts of a raw rubbery dimethylpolysiloxane with a viscosity of 4,000,000 cps that does not contain any vinyl groups and whose molecular chain ends are capped with trimethylsilyl groups, and further replacing the rubbery dimethylpolysiloxane with the formula Polyether modified silicone oil 5
Silicone composition F was prepared using Next, we investigated the curability of the silicone compositions A to F obtained as described above, and the peel resistance, slipperiness, and residual adhesion of the cured films obtained therefrom, and found that the results are shown in Tables 1 and 2. I got good results. This curability was determined by coating these compositions on polyethylene laminate paper at 0.8 g/m ² and heating them at 120°C.
These compositions were applied to polyethylene laminate paper at a concentration of 0.8 g/m ² and treated at 120°C for 60 seconds.
The measurement results for the samples treated for seconds are shown, and the results show that the samples of Example 1 had satisfactory curing properties, peel resistance, slip properties, and residual adhesion rate, but the samples of Comparative Examples Examples 1, 2, and 3 have poor slip properties, Comparative Example 4 has good slip properties but poor curing properties and residual adhesion, and Comparative Example 5 has good slip properties and good texture, but curing properties and residual adhesion properties. It was confirmed that this is bad.

【table】

[Table] Example 2, Comparative Example 6 Both ends of the molecular chain are blocked with dimethylvinylsilyl groups, and four vinyl groups are bonded to the side chains of polysiloxane. Vinyl group content is 2.0 mol% and viscosity 100 parts of a copolymer of dimethylsiloxane and methylvinylsiloxane with a viscosity of 2000 cps, with a vinyl group content of 0.15 mol% and a viscosity of
Two parts of a copolymer of dimethylsiloxane and methylvinylsiloxane with a yield of 1,000,000 cps, both ends of the molecular chain were blocked with trimethylsilyl groups.

[Formula] 6 parts of methylhydrodiene polysiloxane containing 95 mol% units and having a viscosity of 40 cps and 3-methyl-1 used in Example 1
- After adding 20 parts of butyne and mixing uniformly, a platinum-vinylsiloxane complex salt of 120 ppm in terms of platinum was added thereto and mixed well to prepare silicone composition G. For comparison, instead of the above copolymer of dimethylsiloxane and methylvinylsiloxane with a viscosity of 2000 cps, both ends of the molecular chain are blocked with dimethylvinyl groups, but vinyl groups are bonded to the side chains of polysiloxane. Silicone composition H was prepared in the same manner as described above, except that 100 parts of methylvinylsiloxane, which had a vinyl group content of 2.0 mole % and a viscosity of 220 cps, was used. Next, the curability of the silicone compositions G and H and the physical properties of the cured films obtained therefrom were examined, and the results shown in Table 3 were obtained.

[Table] Example 3, Comparative Example 7 Both ends of the molecular chain are blocked with methylvinylsilyl groups, and three vinyl groups are bonded to the side chain of polysiloxane. Vinyl group content is 7.0 mol% and viscosity 100 parts of a copolymer of dimethylsiloxane and methylvinylsiloxane with a viscosity of 200 cps, 15 parts of dimethylpolysiloxane with a viscosity of 500,000 cps, with both ends of the molecular chain blocked with dimethylhydroxysilyl groups,
Both ends of the molecular chain are blocked with trimethylsilyl groups,

[Formula] Methylhydrodiene polysiloxane with a viscosity of 20 cps containing 70 mol% of units
10 parts and 3-methyl-1- used in Example 1
To the mixture of 1.0 part of butyne and homogeneous stirring, 100 ppm of platinum-vinylsiloxane complex salt (in terms of platinum) was added and mixed well to form a silicone composition.
I made it. For comparison, instead of the above copolymer of dimethylsiloxane and methylvinylsiloxane with a viscosity of 200 cps, both ends of the molecular chain are blocked with dimethylvinylsilyl groups, and the side chains of the polysiloxane have 8 vinyl groups. A copolymer of dimethylpolysiloxane and methylvinylsiloxane with a vinyl group content of 12.0 mol% and a viscosity of 200 cps.
Silicone Composition J was prepared in the same manner as above except that 100 parts were used. Next, when this silicone composition J was examined for its curability and the physical properties of the cured film obtained from it, the results shown in Table 4 were obtained.

【table】

Claims (1)

[Claims] 1. Contains at least two silicon-bonded vinyl groups (at least one of which is in a side chain) in one molecule, and the vinyl group accounts for 0.5 of the total organic groups.
~10.0 mol%, and the viscosity at 25℃ is ~50
100 parts by weight of a substantially linear organopolysiloxane with a viscosity of 100,000 cps or more at 25°C, having a hydroxyl group bonded to a silicon atom at the end of the molecular chain; organopolysiloxane
0.5 to 40 parts by weight, 3 organohydrodiene polysiloxane containing at least two silicon-bonded hydrogen atoms per molecule, 0.5 to 50 parts by weight, and 4 a catalytic amount of a platinum-based compound. Contains no organic solvents at 25℃
1. A silicone composition for release paper, which has a viscosity of 50 to 10,000 cps.