JP2001172568A - Primer composition and silicone laminate - Google Patents

Abstract

(A) An organohydrogenpolysiloxane having at least three hydrogen atoms bonded to a silicon atom in one molecule as a main component, and (B) an amount required for curing a transition metal catalyst (C) Reaction control agent A primer composition characterized by containing an amount necessary for reaction control as a main component. The primer composition of the present invention can provide a primer layer having excellent adhesion to a plastic substrate and having little deterioration with time of adhesion. In the silicone laminate of the present invention, the base material and the cured silicone layer are in good contact with each other, and there is little deterioration over time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer composition used for improving the adhesion between a substrate and a silicone cured layer by coating on a substrate, and a substrate using the primer composition. And a silicone laminate comprising a silicone cured layer.

[0002]

2. Description of the Related Art
A silicone cured film layer is formed on a substrate such as plastic, glass, metal, etc. for the purpose of protective coating, hard coating, heat and chemical resistance coating, etc. In addition, it has been practiced that a substrate is treated with a primer with a silane coupling agent or the like to improve the adhesion between the substrate and the silicone layer.

When such a primer layer is provided,
Apply an organic solvent solution of a silane coupling agent to the substrate,
It is a common method to heat and bake, but this method emits a gas containing an organic solvent, and there is a problem unfavorable in environmental hygiene, and this method is not effective for substrates without heat resistance . There are various methods for curing the silicone composition. In particular, the addition-curable silicone composition is inferior in adhesion to a substrate, especially a plastic. It was difficult to form a silicone cured film of a mold with good adhesion to plastic.

On the other hand, in order to prevent adhesion and sticking between a substrate such as paper, processed paper, and plastic film and a pressure-sensitive adhesive substance, heat, ultraviolet rays,
Forming a silicone cured film with an electron beam-curable silicone composition has been performed, and paper, plastic films, and the like on which such a releasable cured film has been formed are generally called release paper.

[0005] As a release composition (release agent) for forming such a release silicone cured film, it can be applied at a low temperature and in a short time in order to improve productivity and save energy and to be applied to a substrate having poor heat resistance. Is required to be cured. Generally, as the peelable composition, a thermosetting silicone composition, particularly an addition reaction-curable silicone composition, is widely used because of its excellent peeling properties and excellent low-temperature curability. A cured film of the composition has poor adhesion to a plastic film and may easily fall off when rubbed with a finger or the like.

In order to improve the adhesion, a method of applying a silane coupling agent on a substrate and providing a primer layer is known (Japanese Patent Publication No. 5-83074). However, there were still problems such as the use of an organic solvent for application of the agent, the decrease in adhesion over time, and the effect obtained was insufficient.

[0007] The present invention has been made in view of the above circumstances,
A primer composition that provides a primer layer that has good adhesion to a silicone cured layer such as an addition-reaction-curable type to a substrate such as a plastic, and that does not deteriorate in adhesion over time, and a substrate using the primer composition It is an object of the present invention to provide a silicone laminate in which a silicone cured layer is in good contact with a silicone cured layer.

[0008]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, have formed a primer layer on the surface of a substrate on which a silicone cured layer is to be formed. As a means, it has been found that a method of curing an organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule with a transition metal catalyst is very effective.

In other words, such a curing method can be applied to a substrate without using a solvent, and a primer layer can be formed by heating for a short time after the application. A primer layer can be formed on such a base material, and the obtained primer layer has excellent adhesion to an addition-curable silicone cured layer, and its change with time is small. Therefore, for example, a plastic film substrate having a primer layer formed from the composition of the present invention,
The present invention has been found that when an addition reaction-curable silicone cured layer is laminated, the silicone cured layer adheres well to the substrate and gives an excellent silicone laminate which does not detach from the substrate over time. It is what led to.

Accordingly, the present invention provides: [I] (A) an organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule as a main component, and (B) curing of a transition metal catalyst. Required amount (C) Reaction control agent Primer composition characterized by having the necessary amount for reaction control as a main component, and [II] a cured film of the primer composition is formed on a base, and Provided is a silicone laminate having a silicone cured layer formed thereon.

Hereinafter, the present invention will be described in more detail. In the primer composition of the present invention, the organohydrogenpolysiloxane as the component (A) is a main component of the composition of the present invention. Therefore, it is necessary that one molecule has at least three hydrogen atoms bonded to silicon atoms in one molecule.

Here, as the above-mentioned organohydrogenpolysiloxane, those represented by the following general formula (1) are preferable. ^{_{(SiO 2) p (R 1}} SiO 3/2) q (R 1 2 SiO) r (R 1 3 SiO 1/2) s (1)

In the above formula, R ¹ is a different or the same type of hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10, preferably 1 to 8 carbon atoms.
Alkyl groups such as methyl group, ethyl group, propyl group and butyl group, cycloalkyl groups such as cyclohexyl group, aryl groups such as phenyl group and tolyl group, or part of hydrogen atoms bonded to carbon atoms of these groups Or a hydroxypropyl group, a cyanoethyl group, a 1-chloropropyl group, a 3,3,3-trioxy group, all of which are substituted with a hydroxy group, a cyano group, a halogen atom, an epoxy group, a (meth) acryl group, a (meth) acryloyl group, or the like. It is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms such as a fluoropropyl group.
p, q, and s are each an integer of 0 or more, r is an integer of 3 or more, and preferably p is 0 to 5, q is 0 to 10, and s is 0.
-50, r is 3-1,000, more preferably p
Is 0 to 2, q is 0 to 5, s is 0 to 10, r is 3 to 500.
It is.

In the present invention, it is considered that the adhesion to the substrate is exhibited by hydrogen atoms bonded to silicon atoms. Therefore, in the above-mentioned organohydrogenpolysiloxane, the ratio of silicon atoms to which hydrogen atoms are directly bonded is reduced. It is preferably at least 50% (% by weight, hereinafter the same) of the whole, more preferably at least 70%. The ratio of silicon atoms to which hydrogen atoms are directly connected is 100
%. In the present invention, since the proportion of silicon atoms having hydrogen atoms in the component (A) contributes to the development of adhesion, if the proportion of silicon atoms having hydrogen atoms is too small, the primer effect may decrease. There is.

More generally, among the substituents R ¹ , those in which 90% by mole or more of all organic groups other than hydrogen atoms are methyl groups are advantageous in terms of cost, but depending on the required characteristics, What contains an appropriate organic group may be used. For example, if the silicone to be laminated contains a polar functional group, the silicone layer and the primer layer can be laminated by using an organohydrogenpolysiloxane containing an epoxy group, a (meth) acrylate group and the like in the molecule. Adhesion is improved. In this case, the organic group in the organohydrogenpolysiloxane must be one that does not hinder any curing reaction of the primer layer and the silicone layer to be laminated.

The molecular structure of the organohydrogenpolysiloxane is not particularly limited, and may be any of a chain, a branch, and a ring. From the viewpoints of workability and coating properties, the viscosity at 25 ° C. is 5%. It is preferably from 〜 to 50,000 centipoise (cP), particularly preferably from 10 to 5,000 cP. An example of such an organohydrogenpolysiloxane is shown below.

[0017]

Embedded image (In the above formula, Me = CH ₃ , Ph = C ₆ H ₅ , p and s are 3 or more, q, r, t are integers of 0 or more, and s + t is an integer of 3 or more.)

As the transition metal catalyst of the component (B),
Any component can be used without particular limitation as long as it promotes the dehydrogenation reaction of the hydrogen atom bonded to the silicon atom of the organohydrogenpolysiloxane of the component (A). Specifically, platinum-based catalysts such as chloroplatinic acid, an alcohol solution of chloroplatinic acid, a reaction product of chloroplatinic acid with an alcohol or an aldehyde, a complex of chloroplatinic acid with various olefins, and a vinyl group-containing siloxane are preferable. In addition, it is also possible to use a transition metal catalyst used in a general addition reaction such as a palladium catalyst, a rhodium catalyst, and a ruthenium catalyst.

The amount of these catalysts added is not particularly limited as long as it is an amount necessary for curing the composition, but the transition metal catalyst is added to the organohydrogenpolysiloxane of the component (A) in an amount of 1 to metal equivalent weight. 1,000 ppm, especially 10-2
It is desirable to add in the range of 50 ppm. If the amount is too small, poor curing may occur. If the amount is too large, the dehydrogenation reaction may occur rapidly, making the curing reaction uncontrollable and economically disadvantageous.

The reaction control agent used in the present invention suppresses the reaction of the composition at around room temperature. Specifically, a alkenyl group-containing organopolysiloxane and an organohydrogen are generally prepared using a transition metal catalyst. The same compounds as those used for the addition reaction with the polysiloxane can be used.

Examples of the reaction control agent include acetylene alcohols (JP-B-44-31476, JP-A-6-3-3).
29917), silylated acetylene alcohols (JP-A-61-261) and JP-A-9-1433.
No. 71, Japanese Patent Application No. 10-253454, and the like using two or more reaction control agents are effective. Specifically, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol,
3-methyl-1-penten-3-ol, 1-ethynylcyclohexanol, 1,1,3,3-tetramethyl-
Examples thereof include 1,3-divinyldisiloxane, methylvinylcyclotetrasiloxane, and 3-methyl-3-trimethylsiloxy-1-pentyne. Of these, 1
A combination of -ethynylcyclohexanol and 3-methyl-3-trimethylsiloxy-1-pentyne is preferred from the viewpoint of pot life and curability.

The amount of the reaction control agent is not particularly limited as long as it can control the dehydrogenation reaction of the component (A).
(A) Component organohydrogenpolysiloxane 1
It is preferably 0.1 to 5 parts by weight based on 00 parts by weight.

The composition of the present invention may further include a leveling agent, an antistatic agent,
An antifoaming agent, a pigment and the like may be added. The feature of the primer composition of the present invention is that it can be used without a solvent, and it is recommended that the primer composition be used without a solvent from the viewpoint of environmental hygiene.However, the primer composition may be diluted with a solvent as necessary for the purpose of adjusting a coating amount. May be. Examples of the solvent include aliphatic or aromatic hydrocarbons such as hexane, heptane, toluene, and xylene; esters such as ethyl acetate and butyl acetate; and carbonyl compounds such as methyl ethyl ketone and methyl isobutyl ketone. In this case, the concentration of the silicone as the component (A) is preferably about 0.01 to 20%.

The substrate on which the primer composition of the present invention can be coated includes polyester, polypropylene,
Plastic films and sheets obtained from synthetic resins such as polyethylene, polyvinyl chloride, polytetrafluoroethylene, and polyimide, or composite materials of these synthetic resins with synthetic fibers, inorganic fibers, nonwoven fabrics, etc., glassine paper, clay-coated paper, etc. Paper base, laminated paper such as polyethylene laminated paper, metals such as aluminum, iron and copper, ceramics, glass, etc., and are particularly useful in plastic films.

To apply the present composition to a substrate, known methods such as roll coating, gravure coating, wire doctor coating, air knife coating, and dipping coating can be used. 0.0005 to 2.0 g /
m ² , preferably 0.001 to 0.5 g / m ² .
If the coating amount is less than 0.0005 g / m ² , a sufficient primer effect may not be obtained. Thereafter, the primer layer can be formed by heating in a conventional manner. The heating temperature is appropriately selected, but is preferably 50 to 1
It can be about 50 ° C.

The composition of the silicone cured layer to be laminated after the primer treatment may be of any type, such as an addition reaction type using a platinum catalyst, a condensation reaction type using a tin catalyst, and a radical reaction using a radical polymerization initiator. And a cationic curing type using a cationic polymerization initiator, and a composite curing type thereof. In the present invention, a known composition containing an organopolysiloxane containing two or more alkenyl groups in one molecule, an organohydrogenpolysiloxane containing two or more SiH groups in one molecule, and a platinum-based catalyst Is particularly effective.

The form may be any of a solvent type, a non-solvent type and an emulsion type. In addition, as a method of coating on the primer layer, known methods such as roll coating, gravure coating, wire doctor coating, air knife coating, dipping coating can be used, and a general laminating method is not limited to these. can do. The curing method may be any of heat curing, ultraviolet curing, and electron beam curing.

This silicone laminate is suitably used as a release paper, particularly when the cured silicone layer has releasability.

[0029]

Industrial Applicability The primer composition of the present invention can provide a primer layer having excellent adhesion to a plastic substrate and having little deterioration with time of adhesion. In the silicone laminate of the present invention, the base material and the cured silicone layer are in good contact with each other, and there is little deterioration over time.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In addition, the viscosity in each example is a value at 25 ° C., and all parts represent parts by weight.

Examples 1 to 3 100 parts of the organohydrogenpolysiloxane shown in Table 1, 0.24 parts of 1-ethynylcyclohexanol, and 1.35 parts of 3-methyl-3-trimethylsiloxy-1-pentyne were used. Mix uniformly and add 5.0 parts (0.025 part in terms of platinum weight) of a toluene solution of a complex of chloroplatinic acid and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane. A silicone coating solution was prepared by mixing uniformly, and was applied on a substrate shown in Table 1 using an offset printing machine so that the coating amount was 0.3 g / m ^{2, and} was applied with a hot air drier. C. for 30 seconds to form a primer layer.

On this substrate, an addition reaction type solvent-free silicone release agent (KNS-320, manufactured by Shin-Etsu Chemical Co., Ltd.)
A) 100 parts of platinum-based catalyst (Shin-Etsu Chemical Co., Ltd.
CAT-PL-56) A mixture of 2 parts was applied using an offset printing machine so that the coating amount became 0.6 g / m ^2, and heated at 140 ° C. for 30 seconds with a hot air dryer to form a silicone release film. Was formed.

In order to evaluate the adhesiveness of the silicone release film to the substrate, immediately after the film was formed and after 30 days, the coated surface was strongly rubbed with a finger, and a rub-off test was performed to determine whether or not the film came off. The results are also shown in Table 1.

Comparative Example 1 Addition-reaction type solvent-free silicone release agent (KNS-320A, manufactured by Shin-Etsu Chemical Co., Ltd.) 100 directly on a substrate without performing the above-mentioned primer treatment.
Part is a platinum-based catalyst (CAT-P manufactured by Shin-Etsu Chemical Co., Ltd.)
L-56) A mixture of 2 parts was coated at a coating amount of 0.6 g / m.
^The composition was applied using an offset printing machine so as to be ^2, and heated at 140 ° C. for 30 seconds with a hot air drier to form a silicone release film.

Similarly, in order to evaluate the adhesion of the silicone release film to the substrate, immediately after the film was formed and 30 days later, the coated surface was strongly rubbed with a finger, and a rub-off test was performed to determine whether or not the film came off. The results are also shown in Table 1.

[0036]

[Table 1]

Claims (5)

[Claims] (A) An organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule as a main component, and (B) a necessary amount for curing a transition metal catalyst (C) Reaction control A primer composition characterized by having a necessary amount for controlling the reaction as a main component. 2. The primer according to claim 1, wherein the component (A) is an organohydrogenpolysiloxane represented by the following general formula (1) and having at least three hydrogen atoms bonded to silicon atoms in one molecule. Composition. ^{_{(SiO 2) p (R 1}} SiO 3/2) q (R 1 2 SiO) r (R 1 3 SiO 1/2) s (1) ( wherein R ¹ is 1 to 10 hydrogen atoms or carbon atoms Is an unsubstituted or substituted monovalent hydrocarbon group. P, q, and s are each an integer of 0 or more, and r is an integer of 3 or more.) 3. A silicone laminate comprising a cured film of the primer composition according to claim 1 formed on a base material and a cured silicone layer formed thereon. 4. The silicone laminate according to claim 3, wherein the cured silicone layer is a cured layer of an addition-curable silicone composition. 5. The silicone laminate according to claim 3, which is a release paper.