JPH0253859A - Silicone composition for mold release paper - Google Patents

Abstract

PURPOSE:To obtain a silicone composition for mold release paper having excellent shelf stability before coating, excellent curing properties after coating and improved workability free from flammability and smell by blending a specific organosiloxane with a specific amount of a specific methylhydrogen polysiloxane, etc. CONSTITUTION:(A) 100 pts.wt. organopolysiloxane of straight-chain structure containing two or more vinyl-silicon bonds in one molecule and vinyldimethylsilyl groups or trimethylsilyl groups at both ends is blended with (B) 2-30 pts.wt. methylhydrogen polysiloxane containing two or more hydrogen- silicon bonds in one molecule, (C) 0.1-10 pts.wt. silylated maleic ester compound shown by the formula (R<1>, R<2> and R<3> are 1-10C aliphatic hydrocarbon and one of R<1>, R<2> and R<3> are olefinic unsaturated group) and (D) 2-50ppm calculated as platinum of a platinum-based compound.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a silicone composition for release paper.

More specifically, the present invention has excellent storage stability at room temperature after adding a catalyst until application, while curing at low temperatures and in a short time after being applied to various types of paper, plastic films, and other substrates. The present invention relates to a silicone composition for release paper.

(Prior art) Conventionally, an organopolysiloxane containing an aliphatic unsaturated group bonded to a silicon atom and an organohydrodienepolysiloxane having a hydrogen atom (-3iH bond) bonded to a silicon atom are combined in the presence of a noble metal catalyst. So-called addition reaction type silicone compositions, which are reacted in the following manner, are widely used for various purposes and are also used for release paper. however,
In order to use this addition reaction type silicone composition for release paper, it is usually heated at 100°C to 150°C, 110 seconds to 30
It is necessary to form a cured film in a short period of time, such as seconds.
Therefore, there were problems in that the pot life was short and it was difficult to balance the hardening properties. Methods to solve this problem include those in which CCL is added as an addition reaction control agent (Japanese Patent Publication No. 47-6111), acetylene alcohol is added (Japanese Patent Publication No. 4131476), and acrylonitrile is added (Japanese Patent Publication No. 4131476). Special Public Service 1977
-22018), 1,3-dichloropropene added (Japanese Unexamined Patent Publication No. 61-238851), maleates added (US Patent Publication No. 4,256,
No. 807, No. 4゜530.989, No. 4,562,0
No. 96) etc. have been proposed.

However, when CCZ4 is added as a control agent, there is no effect of suppressing the addition reaction unless it is used in large quantities. Therefore, the difference between the effect as a solvent in solvent dilution and the effect as a solvent is not clear, and it is impossible to obtain a substantially solvent-free coating liquid. Furthermore, when acetylene alcohols are added, since they are reactive with hydrogen-silicon bonds, the hydrogen-silicon bonds as curing functional groups contained in the composition are consumed over time, resulting in hardening. Not only does it have the disadvantage of reduced properties, but it is also volatile and has a low flash point, so if it is used as a solvent-free coating solution, there is a limit to the amount it can be added due to safety concerns.

Furthermore, in the case of acrylonitrile, the addition reaction inhibitory effect is weak and adding a small amount is ineffective, so if a large amount is added to exert the inhibitory effect, a composition containing a large amount of acrylonitrile will not cure properly, and acrylonitrile Environmental problems also arise because they emit a peculiar odor.

The above-mentioned drawbacks can be improved by using diallyl maleate esters, maleimides, hydrocarboxymalates, etc. as addition reaction inhibitors, but these all have low solubility in organopolysiloxanes, so the composition cannot be made uniform. There is a limit to the amount of addition when curing a thin film, and it was not satisfactory.

The inventors of the present invention have made intensive studies to solve the drawbacks of the conventional methods, and have found that silylated maleic ester compounds have an excellent effect of suppressing the addition reaction, have good compatibility with organopolysiloxanes, and have a boiling point of 200°C or higher. The present invention was completed by discovering that there is no occurrence of a high or unusual depth.

Therefore, a first object of the present invention is to provide a silicone composition for release paper that has a longer pot life before application without impairing the curability of the silicone composition after application.

A second object of the present invention is to provide a silicone composition for release paper that is not flammable, does not generate any particular odor, and has good workability.

A third object of the present invention is to provide an addition reaction inhibitor that can relatively lengthen the pot life of an addition reaction-curing silicone composition after addition of a platinum catalyst.

(Means for Solving the Problems) The above aspects of the present invention include (1) at least 2 in one molecule;
(
2) 2 to 30 parts by weight of methylhydrodiene polysiloxane having at least two hydrogen-silicon bonds in one molecule, (3) a silylated maleic ester compound represented by the general formula (in the formula R', , R2 , R3 are the same or different aliphatic hydrocarbon groups having 1 to 10 carbon atoms, R1, R2
, Ril is an olefinically unsaturated group. ): 0.1 to 10 parts by weight, (4) The amount of platinum is 2 to 500 ppm of platinum based compound based on the component (1), and the number of vinyl groups in one molecule of the component (1) This was achieved by a silicone composition for release paper characterized in that the total number of hydrogen-silicon bonds in one molecule of component (2) is at least 5.

Each component used in the present invention will be explained in detail below.

Component (1) is a substantially linear diorganopolysiloxane having vinyldimethylsilyl or trimethylsilyl groups at both ends of its molecular chain, and is represented by the following formula, for example.

Σ In the above formula, R, R' and R'' represent an organic group, and Me represents a methyl group, of which at least 50 mol% is a methyl group, and the remaining organic groups exclude aliphatic unsaturated bonds. It is an organic group. Examples of organic groups excluding such aliphatic unsaturated bonds include alkyl groups such as ethyl group, propyl group, butyl group, aryl groups such as phenyl group, and halogen substituted products thereof. Can be done.

In the case of a diorganopolysiloxane in which both ends of the molecular chain are vinyldimethylsilyl groups, n is 〇 or a positive integer, and in the case of a diorganopolysiloxane in which both ends of the molecular chain are trimethylsilyl groups, n is It is an integer greater than or equal to 2.

These organopolysiloxanes contain vinyl in one molecule.
As long as it has at least two silicon bonds, it may be used alone or in combination.

Moreover, the viscosity range is 50 cs or more at 25° C. to a gum-like viscosity range. Note that the term "substantially linear shaft" means a linear structure having a linear or partially branched portion.

The methylhydrodiene polysiloxane as component (2) is a methylhydrodiene polysiloxane having at least two hydrogen-silicon bonds in one molecule. However, the number of vinyl groups in one molecule of component (1) and component (2)
The total number of hydrogen-silicon bonds in one molecule of is at least 5
It is necessary that the number of Examples of the methylhydrodiene polysiloxane include CH3HS i O units, H3iO+, s units, (CH3)zsio units, CH
35iO,.

, units, (CHa)z R3iOo, 5 units, or
(CH3)3 S I Oo, homopolymers or copolymers consisting of units are exemplified. This polymer may be a linear polymer, a cyclic polymer or a branched polymer, but is preferably a methylhydrodiene polysiloxane or a dimethyl-methylhydrodiene polysiloxane having a viscosity of 0 to 500 cs at 25°C.

The amount of component (2) added is usually 2 to 30 parts by weight per 100 parts by weight of component (1), considering the formation of a cured film and the peeling performance.
Parts by weight.

Component (3) is a silylated maleic ester compound represented by the general formula,
While imparting storage stability at room temperature (generally room temperature) to the composition of the present invention, the addition reaction suppressing effect is immediately released after coating on paper, plastic, film, etc.
It is a reaction control agent that enables curing in a short time at low temperatures of 0° C. or lower, and is an important component in the composition of the present invention.

In the above general formula, R1, Rz and R3 are methyl groups,
1 to 1 carbon atoms such as alkyl groups such as ethyl group, propyl group, butyl group, alkenyl group such as vinyl group and allyl group
0 aliphatic hydrocarbon group, and at least one of R1, R2 and R3 is an alkenyl group. R1, R2
, Rff contains no alkenyl group, the effect of suppressing the reaction is poor.

R'-3l As a group (silyl group), For example, the following can be mentioned.

CR3 CHz = CHS i- Hz 2 R5 G Hz = CHS i CR3 CH=CH2 CR2=CHS i CH.

CHt CH=CHt CR2=　CHCHz　S　i CH.

CH.

CHz = CHCHt S 1-CH.

CH=CH2 CH2=CH31 CH=CH.

Among these, especially CH3 CH2=CH3i CH3 CH3 CH2-=CHCH2S 1- CH.

CH=CH.

CH2=CHS i CH=　CH2 is preferable, Among them, CH3 CH2=CH3i- HI is most preferred.

The above-mentioned reaction inhibitor dissolves well in the present organopolysiloxane composition for release paper, especially in the solvent-free organopolysiloxane composition, is colorless and transparent, has no odor, and is nonvolatile, so it is suitable for use in solvent-free organopolysiloxane compositions. It is safe and has good workability when applied as a polysiloxane composition to paper, plastic, film, etc.

As mentioned above, since the reaction inhibitor and the organopolysiloxane have good compatibility, the reaction control effect in this composition is stable and the reproducibility of the film curing characteristics is also good.

The curability by heating after applying this composition to the surface of a thin film substrate such as paper or film is determined by the reaction inhibitor component (3).
), but it is appropriate to add 0.1 to 10 parts by weight per 100 parts by weight of component (1).

If it is less than 0.1 part by weight, the storage stability of the composition at room temperature will be poor and the viscosity will increase in a short period of time. If the amount is 10 parts by weight or more, the storage stability at room temperature is very good, and the viscosity of the treatment bath hardly changes even after a long period of time, but the curability after application is significantly reduced, so the curing time must be lengthened or the curing time must be increased. This is not preferred because the temperature must be increased and the characteristics of the composition will be lost.

The platinum compound as component (4) used in the present invention is:
Catalysts for the addition reaction of components (1) and (2) can be appropriately selected from known catalysts. Examples of these catalysts include chloroplatinic acids such as monochloroplatinic acid and dichloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds, and complex salts of chloroplatinic acid and various olefins. In order to obtain a good cured film and from an economical point of view, the amount of these catalysts to be added is 1 to 1. A range of 000 ppm, particularly a range of 2 to 500 ppm is preferred.

The composition of the present invention can be obtained by blending predetermined amounts of the above components (1) to (4), and the blending method is to uniformly mix the components (1) to (3) in advance, and then It is desirable to add (4). In addition, this composition may include fumed silica, wet silica,
Dyes, pigments, etc. may be added, and the addition of silica has effects such as improving film strength, controlling slipperiness, improving adhesion, and controlling printability.

The composition of the present invention thus obtained has a viscosity of 50 to 10.0 OOcs at 25°C from the viewpoint of workability during application.
It is preferable to use a solvent-free type in the range of .

The viscosity of the composition may be appropriately determined depending on the amount of coating, the coating method, and the type of substrate to be coated. coater,
0.3~ using known techniques such as air coater, curtain flow coater, offset transfer roll coater, etc.
50 to 3,00 when applying with a coating amount of 3g/m2
It is preferable to use a material with a low to medium viscosity such as 0 cps, and to use a material with a higher viscosity than this for substrates that easily soak in, such as glassine paper, kraft paper, and tarley undercoated paper.

The Syrian corn composition for release paper of the present invention prepared as described above has good storage stability at room temperature, and has a 1.
A cured film can be formed in a short period of time under low temperature curing conditions of 00° C. or lower, and does not have an adverse effect on adhesive substances. Note that the composition of the present invention can also form a cured film by irradiation with ultraviolet rays. for example,
By irradiating with an ultraviolet ray irradiator such as 80 W/cm for 1.0 seconds or more, it is possible to provide the same characteristics as in the case of forming a cured film by heat.

(Effects of the Invention) The composition of the present invention uses a silylated maleic ester compound that is highly compatible with organopolysiloxane and has a boiling point of 200°C or higher as a reaction control agent, thereby lowering the flash point of the composition. It is particularly advantageous for solvent-free coating for release paper because it has no odor and no odor, and has good workability because the pot life before coating is stable.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

In addition, all "parts" in the examples represent parts by weight,
Viscosity represents the measured value at 25°C.

(Example 1 and Comparative Examples 1 to 3) Both ends of the molecular chain were blocked with dimethylvinylsilyl groups,
100g of dimethylpolysiloxane with a viscosity of 1.0OOcs
5.0XIO-'' moles of various compounds shown in Table 1 were added to 102 g of a mixture of 2.0 g of methylhydrodiene polysiloxane having a viscosity of 40 cs and having both ends of the molecular chain capped with trimethylsilyl groups and having a viscosity of 40 cs. A silicone composition was prepared and examined for appearance, odor, and flammability.

Next, 1.0 g of platinum vinyl siloxane complex (platinum amount: 0.5%) was added to the above composition to prepare a silicone composition, and the pot life of these was examined, and a polyethylene laminate was prepared using a wire doctor #0. When it was coated on paper to a thickness of 1.0 g/m'' and its curability, peeling force, and residual adhesion rate were examined, the results shown in Table 1 were obtained.

As is clear from the results in Table 1, Comparative Example 1 has a short pot life of 1/2 day or less, and Comparative Example 2 has a flash point of 12
It was demonstrated that the present invention was able to solve all of the problems of these comparative examples, whereas Comparative Example 3 was opaque and had insufficient uniformity. has been done.

In addition, the appearance was visually observed, and the flash point was determined using the sealed method (JISK2
265), and the curing property is 120'C in a hot air circulation dryer.
Evaluation was made based on the state of the cured film after curing for 30 seconds.

The evaluation was rated O if there was no clouding or falling off when rubbed with fingers. In addition, pot life represents the time it takes to gel when left standing at 25"C, and the degree of peeling is 120°C x 30".
An acrylic solvent-based adhesive Olivine BPS 5127 (trade name manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied to the surface of the film cured by s e c, and after heating for 100 x 30 seconds, Paste the adhesive paper together,
Using a tensile tester, the force (g
).

In addition, the residual adhesion rate was calculated by forming a cured film in the same way as in the case of peeling force, and then laminating polyester Cheeve Lumirror 31B (manufactured by Nitto Electric Industry Co., Ltd.) on the surface.
After aging the tape at 70'C x 20 hours under a load of 200cm/cm'', the tape was peeled off and attached to a stainless steel plate, and the peeling force was measured in the same manner as in the case of the peeling force described above.The numerical value is the peeling force of an untreated standard tape. It is a percentage of the force.

Example 2 Curable properties were obtained in the same manner as in Example 1, except that allyldimethylsilyl, trivinylsilyl, and trimethylsilylated products were used in place of the vinyldimethylsilyl group of the maleic acid silylated product used in Example 1. When the pot life was investigated, good results as shown in Table 2 were obtained.

The results in Table 2 demonstrate the effectiveness of the silicone composition for release paper of the present invention in all cases.

Claims (1)

[Scope of Claims] 1) (1) Organos having a substantially linear structure having at least two vinyl-silicon bonds in one molecule and having vinyldimethylsilyl or trimethylsilyl groups at both ends of the molecular chain. Polysiloxane: 100 parts by weight (2) Methylhydrodiene polysiloxane having at least two hydrogen-silicon bonds in one molecule: 2 to 30 parts by weight (3) General formula ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ The silylated maleic ester compound (in the formula R
^1, R^2, and R^3 are the same or different aliphatic hydrocarbon groups having 1 to 10 carbon atoms, and at least one of R^1, R^2, and R^3 is olefinically unsaturated. It is the basis. )
: 0.1 to 10 parts by weight (4) The amount of platinum is 2 to 50 parts by weight based on the above component (1).
0 ppm of a platinum-based compound, and the total number of vinyl groups in one molecule of component (1) and the number of hydrogen-silicon bonds in one molecule of component (2) is at least 5. A silicone composition for release paper. 2) Viscosity at 25°C is 50-10,00
The silicone composition for release paper according to claim 1, which has a silicone composition of 0 cs. 3) The silicone composition for release paper according to claim 1 or 2, wherein at least one of R^1, R^2, and R^3 is a vinyl group or an allyl group, and the remaining groups are methyl groups.