JP2013100396A - Silicone coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicone coating composition, which has excellent storage stability of coating liquid, and can form a coating film, particularly a laminate film, the film having high hardness, excellent scratch resistance, good adhesiveness and high toughness, and never causing cracks even when subjected to a sudden temperature change.SOLUTION: The silicone coating composition forms a silicone hard coat film directly on a surface of a silicone resin film which is formed by curing a silicone resin composition including a basic catalyst and a curable silicone having an alkoxysilyl group and/or silanol group. The composition includes: (i) a co-(partial) hydrolyzate or co-(partial) hydrolytic condensate of a hydrolyzable silicon compound and silicon dioxide fine particles; (ii) a curing catalyst higher in curing activity than the basic catalyst of the silicone resin composition; and (iii) an organic solvent. According to this, a heat-curable silicone coating composition which satisfies both wear resistance and adhesiveness in a balanced manner, and has excellent storage stability of the coating film can be obtained. A cured film of the composition can have excellent scratch resistance since it can be laminated to form a thick film.

Description

  The present invention relates to a silicone coating composition. Specifically, a silicone hard coat that coats the surface of a silicone resin film and heat cures to give a coating film with high hardness, excellent scratch resistance and crack resistance, and excellent storage stability of the coating liquid Relates to the composition.

  Conventionally, hydrolyzable organosilane has been hydrolyzed or partially hydrolyzed as a coating agent that forms a surface protective coating for the purpose of imparting high hardness and scratch resistance to the surface of organic resin substrates such as plastics. A coating agent comprising the resulting composition, or a coating agent obtained by mixing colloidal silica with the composition is known.

  For example, JP-A-51-2736 (Patent Document 1), JP-A-53-130732 (Patent Document 2), and JP-A-63-168470 (Patent Document 3) include organoalkoxysilanes, There has been proposed a coating agent comprising the hydrolyzate of organoorganosilane and / or its partial condensate and colloidal silica, wherein an alkoxy group is converted into silanol with an excess of water.

  The coatings obtained with these coating agents have high hardness and are excellent for protecting the base material, but have poor toughness. For thick coatings, use them outdoors during heating and curing, when taking them out of a curing furnace. Cracks are easily generated when a sudden temperature change occurs. In particular, when a non-buffered basic compound as a curing catalyst, for example, an amine such as triethylamine, benzyltrimethylamine or pyridine, an alkali metal hydroxide such as sodium hydroxide or sodium methoxide, or an alkoxide is used. Although the hardness of the resulting coating film is very excellent, coating film cracks are likely to occur, and the storage stability of the coating liquid is also significantly reduced.

  Buffered basic compounds such as alkali metal salts of carboxylic acids such as potassium formate, sodium acetate, potassium propionate, acetic acid as curing catalysts for achieving both high hardness of the coating and storage stability of the coating liquid Amine carboxylates such as ammonium, dimethylamine acetate, ethanolamine acetate, and dimethylaniline formate, and quaternary ammonium carboxylates such as tetramethylammonium acetate, benzyltrimethylammonium acetate, and tetraethylammonium benzoate are used. -71654 (Patent Document 4).

  However, in view of storage stability as a curing catalyst, these coating compositions are relatively low in alkoxysilane hydrolysates / condensates despite the use of buffered basic catalysts. The main component is a molecular weight, and the reactivity of silanol contained in these is very high, and the content thereof is large, so that their condensation reaction occurs gradually even at room temperature, resulting in a high molecular weight over time. The hardness of the coating film may be reduced or gelled, and the problem that it cannot be used as a coating agent still remains.

  In particular, in order to form a thick film with a silicone coating agent, a silicone layer is directly laminated on a silicone layer, and a silicone layer that is crosslinked with the same basic catalyst on the surface of the silicone film once cured with the basic curing catalyst. Since it is difficult to form a film with good adhesion, the laminated top film has a defect that it easily cracks when it undergoes a rapid temperature change during heat curing or outdoor use. It was.

JP-A 51-2736 JP-A-53-130732 JP 63-168470 A Japanese Patent Laid-Open No. 9-71654

  The present invention has been made in view of the above circumstances, and has excellent storage stability of the coating liquid, high hardness, excellent scratch resistance, good adhesion, high toughness, and rapid temperature change. However, it aims at providing the silicone coating composition which can form the coating film which does not generate | occur | produce a crack, especially a laminated film.

  As a result of diligent studies to achieve the above object, the inventors of the present invention have excellent storage stability of the coating liquid, and as a silicone coating composition capable of forming a silicone hard coat film laminated on the surface of the silicone resin film, It has been found that a composition containing i) a hydrolyzable silicon compound and silicon dioxide fine particles, <ii> a curing catalyst, and <iii> an organic solvent is effective. In this case, the curing catalyst used in this composition is stronger in curing activity than the curing catalyst used for forming the lower silicone resin cured film on which the silicone hard coat film is laminated by this composition, that is, is basic. By using a high curing catalyst and preferably combining it with an appropriate control agent, the coating solution has excellent storage stability, high hardness and scratch resistance, good adhesion, and high toughness. The inventors have found that a thick film that does not generate cracks can be formed even when there is an abrupt temperature change.

  The curing catalyst in the silicone coating composition for forming the silicone hard coat film is an acidic control agent that imparts storage stability, and promotes the condensation reaction of silanol groups and alkoxysilyl groups of the silicon compound by crosslinking. It is preferably formed from a basic curing agent that advances the curing and also develops the hardness of the hard coat layer and the adhesion to the substrate. A weakly active curing system can be made from a weakly active catalyst and a highly active control agent, or with a small amount of catalyst and a large amount of a controlling agent. It can be made from a control agent system or from a large amount of catalyst and a small amount of control agent system.

  In the present invention, the curing catalyst used in this composition is a curing catalyst having a curing activity stronger than the curing catalyst used in the silicone resin cured film, and preferably an appropriate control agent is combined therewith. Therefore, it is possible to form a thick film that has excellent storage stability, high hardness, excellent scratch resistance, good adhesion, high toughness, and no cracks even when there is a sudden temperature change. .

In this case, the curing catalyst of the silicone coating composition forming the silicone hard coat film is composed of a curing agent of a basic organic compound and a control agent of an acidic organic compound, and the basic organic compound is an ammonium compound of the following general formula (1) It is preferable that The curing activity of this basic organic compound can be controlled by selecting the substituents R ¹ , R ² , R ³ and R ⁴ , and the catalyst having a weak curing activity may be an alkylammonium compound other than methyl. A strong catalyst may be a methyl alkylammonium compound. Although it accelerates the condensation reaction and cures by crosslinking, there is a risk of gelation during storage with this alone, so condensing silanol groups and alkoxysilyl groups during storage by using an acidic control agent together It is preferable to control the reaction to develop appropriate storage stability of the coating liquid and formation of a cured film.

Accordingly, the present invention provides the following silicone coating composition.
<1> Silicone directly forming a silicone hard coat film on the surface of a silicone resin film formed by curing a silicone resin composition containing a base catalyst and a curable silicone having an alkoxysilyl group and / or a silanol group A coating composition comprising:
<I> Co (partial) hydrolyzate or co (partial) hydrolyzed condensate of hydrolyzable silicon compound and silicon dioxide fine particles,
<Ii> A silicone coating composition comprising a curing catalyst having a curing activity stronger than that of the base catalyst of the silicone resin composition, and <iii> an organic solvent.
<2> The curing catalyst of the above <ii> component comprises a curing agent of a basic organic compound and a control agent of an acidic organic compound, and the basic organic compound is an ammonium compound represented by the following general formula (1). <1> The silicone coating composition according to <1>.
[(R ¹ ) (R ² ) (R ³ ) (R ⁴ ) N] ⁺ X ⁻ (1)
Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or a halogenated alkyl group, and X ⁻ represents a hydroxide anion or an organic carboxylic acid. Anion.)
<3> The curing catalyst of the above <ii> component comprises a curing agent in which at least one of R ^{1 to} R ⁴ in formula (1) is a methyl group and a control agent for an acidic organic compound, <2> The silicone coating composition according to <2>, wherein the base catalyst comprises a curing agent in which all of R ^{1 to} R ⁴ in formula (1) are alkyl groups having 2 or more carbon atoms and a control agent for an acidic organic compound.
<4> Curing of the base catalyst of the silicone resin composition, wherein the curing agent of the curing catalyst of the <ii> component is a compound selected from tetramethylammonium hydroxide, tetramethylammonium acetate, and tetramethylammonium formate. <3> The silicone coating composition according to <3>, wherein the agent is tetrabutylammonium hydroxide.

  According to the present invention, there can be obtained a heat-curable silicone coating composition that is free from cracks in the coating film, can balance both wear resistance and adhesiveness, and is excellent in storage stability of the coating film. Since the cured coating can be laminated to form a thick film, it can be excellent in scratch resistance.

  The silicone coating composition of the present invention is a composition capable of forming a silicone hard coat film laminated on the surface of a silicone resin film, comprising: <i> a co-hydrolyzed product of a hydrolyzable silicon compound and silicon dioxide fine particles Or a cohydrolyzed condensate, <ii> a curing catalyst, and <iii> an organic solvent, characterized in that a curing catalyst having a curing activity stronger than that of the curing catalyst used in the silicone resin cured film is used. A silicone coating composition.

The curing catalyst that embodies the present invention is preferably composed of a curing agent of a basic organic compound and a control agent of an acidic organic compound, and the basic organic compound is preferably an ammonium compound represented by the following general formula (1).
[(R ¹ ) (R ² ) (R ³ ) (R ⁴ ) N] ⁺ X ⁻ (1)
Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or a halogenated alkyl group, and X ⁻ represents a hydroxide anion or an organic carboxylic acid. Anion.)

Below, each component of this invention is demonstrated in detail.
1) <i> Component The <i> component of the composition of the present invention is a co- (partial) hydrolyzate of at least one hydrolyzable silicon compound represented by the following general formula (A) and silicon dioxide fine particles or It is a co- (partial) hydrolysis condensate.
R ' _a Si (OR ") _(4-a) (A)
(In the formula, R ′ represents an organic group having 1 to 18 carbon atoms, R ″ represents the same or different organic group having 1 to 6 carbon atoms, and a is an integer of 0 ≦ a ≦ 2.)

  R 'is an organic group having 1 to 18 carbon atoms, and an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms is particularly preferable. As these monovalent hydrocarbon groups, linear, branched or cyclic such as methyl, ethyl, propyl, butyl, hexyl, decyl, cyclohexyl, 1,1,2-trimethylpropyl, etc. An alkyl group, an allyl group such as a phenyl group and a tolyl group, an aralkyl group such as a benzyl group and a phenylethyl group, an alkenyl group such as a vinyl group, an allyl group, a propenyl group and a butenyl group. Among these, an alkyl group is preferable, and a methyl group is most preferable when used for applications requiring particularly scratch resistance and weather resistance.

  (OR ″) is a hydrolyzable group, and examples thereof include a hydrolyzable group having 1 to 6 carbon atoms. Specific examples include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a phenoxy group, and an isopropenoxy group. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable from the viewpoint of operability, ease of distilling off byproducts, and stability, and a methoxy group and an ethoxy group are particularly preferable. From the viewpoint of the hardness, wear resistance, and adhesion of the agent, it is preferable that the trifunctional hydrolyzable silane (a = 1 silane) is contained in an amount of 40 mol% or more, particularly 50 mol% or more, preferably 100 mol%. May be.

  Specific silicon compounds include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyl Examples include trimethoxysilane, phenyltrimethoxysilane, cyclohexyltrimethoxysilane, and the like.

  When the silicon compound is co-hydrolyzed with silicon dioxide fine particles to be described later, the upper limit of the amount of water is not limited, but is usually 10 mol or less, particularly 5 mol or less with respect to 1 mol of the silicon compound. Further, the lower limit is preferably 1 mol or more, particularly 1.2 mol or more.

  It is preferable to add a polar organic solvent to the water used for the hydrolysis. Examples of the polar organic solvent include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, t-butanol, diacetone alcohol and the like, ethylene Examples include glycol, monoethylene glycol monoether, propylene glycol, and propylene glycol monoether.

  The <i> component can be prepared by adding an ultraviolet absorber as the other component. As this ultraviolet absorber, a compound having a benzophenone-based skeleton in the molecule and contributing to the absorption of ultraviolet rays can be used.

  The silicon dioxide fine particles cohydrolyzed with the hydrolyzable silicon compound have a role of a filler that gives the coating film hardness and abrasion resistance, and a bond with the silanol group in the <i> component as a binder on the particle surface. In order to form, it is thought to play a role as a crosslinking agent. That is, the surface of the fine particles has a hydroxyl group (Si—OH), and bond formation (Si—O—Si) is possible with the <i> component. As the silicon dioxide fine particles, it is particularly preferable to use a colloidal silicon oxide dispersion, that is, colloidal silica, dispersed in a dispersion medium (oxide sol). The dispersion medium is preferably a polar solvent such as water or alcohol.

  The particle diameter of the silicon dioxide fine particles can be used as long as the transparency of the coating film can be maintained, but is preferably in the range of 1 to 300 nm, particularly 1 to 100 nm. For the purpose of increasing the dispersion stability of the particles, a silane coupling agent, a tetraalkoxysilane such as tetraethoxysilane, a titanium coupling agent, a carboxyl group-containing organic polymer, or the like may be used. However, the main component here is inorganic silicon dioxide, which is added for stabilization, and the organic content used for coating is preferably 10% by mass or less.

  The compounding amount of the silicon dioxide fine particles is preferably 5 to 300 parts by mass, more preferably 5 to 100 parts by mass with respect to 100 parts by mass of the hydrolyzable silicon compound.

  The <i> component is preferably prepared by adding the above aqueous dispersion of silicon dioxide fine particles to the hydrolyzable silicon compound as a raw material. This means that the <i> component is produced in the presence of silicon dioxide fine particles. This method is an efficient production method when an acidic or alkaline water-dispersed silicon dioxide sol is used. In the present invention, it is particularly preferable to use an acidic water-dispersed silicon dioxide sol. Even when this preparation method is used, the amount of water in the water-dispersed silicon dioxide sol is 1 mol or more, preferably 1.2 mol or more, with respect to 1 mol of the hydrolyzable group (OR ″). If the amount is less than 1, the hydrolyzable group remains, resulting in a decrease in hardness and adhesion due to a decrease in crosslink density, although the upper limit of the amount of water is not limited, but is usually 10 mol or less, particularly 5 mol or less. It is.

  A hydrolysis catalyst may be used for the co-hydrolysis. As the hydrolysis catalyst, conventionally known catalysts can be used, and particularly acidic hydrogen halides, carboxylic acids, sulfonic acids, acidic or weakly acidic oxides and inorganic salts, solid acids such as ion exchange resins, etc. Can be used. As these examples, an organic acid typified by acetic acid and maleic acid, a cation exchange resin having a sulfonic acid group or a carboxylic acid group on the surface, and the like can be suitably used. The amount of the hydrolysis catalyst is preferably 0.001 to 10 mol% with respect to 1 mol of the hydrolyzable group (OR ″). The hydrolysis is preferably performed under weakly acidic conditions, and the pH is particularly high. It is preferable to make it react in the range of 2 to 7. When hydrolysis is not performed under weak acidity, the silanol group to produce | generate becomes unstable, a condensation reaction advances, and molecular weight may become large too much.

  In particular, in order to obtain a high hardness of the top film, it is preferable to perform condensation after the hydrolysis. Condensation may be performed continuously following hydrolysis, and is usually performed under heating at a liquid temperature of room temperature or 100 ° C. Gelation may occur at temperatures higher than 100 ° C. Furthermore, condensation can be accelerated | stimulated by distilling off the alcohol produced | generated by hydrolysis under 80 degreeC or more and a normal pressure or pressure reduction. Furthermore, for the purpose of promoting condensation, a condensation catalyst such as a basic compound, an acidic compound, or a metal chelate compound may be added. Before or during the condensation step, an organic solvent may be added for the purpose of adjusting the degree and concentration of condensation, and metal oxide fine particles such as silicon dioxide sol are dispersed in water or an organic solvent. May be added. In general, silicone resin undergoes condensation, increases in molecular weight, and decreases in solubility in water and produced alcohol. Therefore, as an organic solvent to be added, the product is well dissolved and has a boiling point of 80 ° C. or higher. The organic solvent having relatively high polarity is preferred. Specific examples of such organic solvents include alcohols such as isopropyl alcohol, n-butanol, isobutanol, t-butanol, diacetone alcohol; methylpropyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, and the like. Ketones; ethers such as dipropyl ether, dibutyl ether, anisole, dioxane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate; propyl acetate, butyl acetate, cyclohexyl acetate, etc. Examples include esters.

  The number average molecular weight in terms of polystyrene in GPC (gel permeation chromatography) analysis of the silicone product obtained by this condensation is preferably 1,500 or more, more preferably 1,500 to 50,000. More preferably, it is 2,000-20,000. If the molecular weight is lower than this range, the toughness of the coating film is low and cracks tend to occur. On the other hand, if the molecular weight is too high, the hardness tends to be low, and the resin in the coating film is phase-separated. May cause whitening of the coating film.

Moreover, the siloxane resin shown by the following average compositional formula (D) can coexist for the purpose of improving the flexibility of the silicone hard coat film.
R ′ ″ _b Si (OR ″ ″) _c (OH) _d O _{(4-bcd) / 2} (D)
(Wherein R ′ ″ represents the same or different organic group having 1 to 18 carbon atoms, R ″ ″ represents the same or different organic group having 1 to 4 carbon atoms, b, c and d) Is a number satisfying 0.8 ≦ b ≦ 1.5, 0 ≦ c ≦ 0.3, 0.001 ≦ d ≦ 0.5, and 0.801 ≦ b + c + d <2.
It is a component that gives flexibility and prevents cracks while maintaining the high hardness of the hard top coat film.

  This action has a relatively small amount of terminal groups (OR ″ ″ and OH) of the siloxane resin of the formula (D) and is only limitedly involved in the cross-linking reaction of the hard top coating agent. This is probably because it plays a role like a cushioning material. In this case, if the amount of the terminal group is too small, it is not firmly fixed in the film, which may be disadvantageous in terms of solvent resistance. Therefore, the siloxane resin should have a relatively small amount of terminal groups, but can be bonded to the <i> component only to be fixed within the hard topcoat film. It is.

  R ′ ″ is the same or different organic group having 1 to 18 carbon atoms, particularly 1 to 10 carbon atoms, and an unsubstituted or substituted monovalent hydrocarbon group such as an alkyl group, an aryl group, an aralkyl group, an alkenyl group, Examples thereof include a halogen-substituted alkyl group, and an alkyl group and an aryl group are preferable. Examples include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, cyclopentyl, cyclohexyl, phenyl, vinyl, trifluoropropyl, and the like.

  R ″ ″ is the same or different organic group having 1 to 4 carbon atoms, and particularly includes an alkyl group or an alkenyl group. (OR ″ ″) represents a portion other than the silanol group (Si—OH) in the terminal group of the siloxane resin, and specific examples include methoxy group, ethoxy group, propoxy group, butoxy group, etc. A methoxy group and an ethoxy group that are easily available are preferred.

  b, c and d are numbers satisfying 0.8 ≦ b ≦ 1.5, 0 ≦ c ≦ 0.3, 0.001 ≦ d ≦ 0.5, and 0.801 ≦ b + c + d <2. When the content b of R ′ ″ is less than 0.8, the crack preventing property is lowered, and when it exceeds 1.5, the organic group is increased and the hydrophobicity is increased. Therefore, compatibility with the hard top coat layer is increased. Is reduced and bleeding occurs from within the film, so that not only the crack prevention effect is lost, but also appearance defects such as repellency occur. When the content c of OR ″ ″ exceeds 0.3, the amount of terminal groups is large, the ratio involved in the condensation reaction with the <i> component is increased, and crack prevention performance is not exhibited. These alkoxy groups and the like can be quantified by infrared absorption spectrum (IR), alcohol quantification by alkali cracking, or the like.

  When the OH content d exceeds 0.5, the ratio involved in the condensation reaction with the <i> and <ii> components at the time of heat curing increases, resulting in poor hardness and crack resistance. When d is less than 0.001, bond formation with the <i> component is completely eliminated and the film is not fixed in the film, resulting in a decrease in hardness and a decrease in solvent resistance. More preferably, 0.9 ≦ b ≦ 1.3, 0.001 ≦ c ≦ 0.2, 0.01 ≦ d ≦ 0.3, and 0.911 ≦ b + c + d ≦ 1.8.

  The siloxane resin is solid at 40 ° C. or lower. If it is liquid at 40 ° C. or lower, even if a bond is formed between the siloxane resin and the <i> component during heat curing, the hardness and solvent resistance of the coating film are lowered. Moreover, it is preferable that the volatile matter contained in the said siloxane resin is 2 mass% or less by drying at 105 degreeC for 3 hours. If it exceeds 2% by mass, the workability may be deteriorated due to the solid flowing or fusing even at 40 ° C. or lower. The siloxane resin preferably has a softening point of 60 to 90 ° C. When the temperature is lower than 60 ° C., the hardness and wear resistance of the hard top coat film may be lowered. When the temperature is higher than 90 ° C., compatibility with the <i> component and crack resistance may be lowered. The softening point is a value measured by the ring and ball method according to JIS K2207.

  The molecular weight of the siloxane resin can be measured by GPC (gel permeation chromatography). The siloxane resin of the present invention has a weight average molecular weight of 2,000 or more, preferably 2,000 to 10,000, as converted by polystyrene standard measured by GPC. If the molecular weight is less than 2,000, the amount of terminal groups is too large and is involved in crosslinking, resulting in poor crack prevention. If the molecular weight is too large, the compatibility with the <i> component and the like decreases, The film may become opaque.

  The following conventionally known resin production methods can be applied to the production method of the siloxane resin. That is, one or more kinds of hydrolyzable silane compounds, or a mixed solution of these and an organic solvent, are added with water and stirred to cause hydrolysis reaction by bringing the hydrolyzable silane compound and water into contact with each other. This is a method for producing a polymer by reacting silanol groups generated by a decomposition reaction with each other or with other hydrolyzable groups to form a siloxane bond (—Si—O—Si—), followed by condensation polymerization. After the polymerization, neutralization is performed, and finally the organic solvent is distilled off to obtain a solid siloxane resin. This solid resin is different from a solvent-insoluble gel and is dissolved again in an organic solvent. As an advantageous production method particularly for use in the present invention, the hydrolysis is preferably carried out under strongly acidic conditions (particularly, the pH is preferably smaller than 2). Under such strongly acidic conditions, the silanol group contributing to the polycondensation reaction is unstable compared to when weakly acidic, and the reaction proceeds rapidly one after another, resulting in a high molecular weight product.

  The preferred amount of water used for hydrolysis depends on the type of hydrolyzable group of the silane used as the raw material, but when alkoxysilane is used as the raw material, it is less than 1.5 mol with respect to 1 mol of the hydrolyzable group OR ″ ″, Particularly preferred is 0.6 to 1.0 mol. In the condensation polymerization reaction under strongly acidic conditions as in this case, if the amount of hydrolyzed water is 1.5 mol or more, three-dimensional condensation proceeds rapidly and gelation is not suitable. Further, when the raw material is chlorosilane, the amount of hydrolysis water is not particularly limited.

  An organic solvent may be used for hydrolysis, and the organic solvent is preferably a nonpolar solvent having low solubility in water. Specifically, hydrocarbon solvents such as toluene, xylene, and hexane are mainly preferably used. However, if the miscibility with water is too low, the hydrolysis reaction is difficult to proceed. It doesn't matter.

  Specifically, the hydrolyzable silane compound used as a raw material is vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldichlorosilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, tetrachlorosilane, tetra Methoxysilane, tetraethoxysilane, methyltrichlorosilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, propyltrichlorosilane, propyltrimethoxysilane, propyltriethoxysilane, hexyltrichlorosilane, hexyl Trimethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, diphenyldimethoxysilane and the like are preferable. In particular, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and phenyltrimethoxysilane are preferable.

  It is preferable that the compounding quantity of the said siloxane resin is 0-100 mass parts, especially 3-80 mass parts of siloxane resin with respect to a total of 100 mass parts of <i> component. When a siloxane resin is not blended, cracks may occur depending on the thermosetting conditions, and when it exceeds 100 parts by mass, the hardness and wear resistance as a hard top coat may be extremely lowered.

  When the siloxane resin is blended, an organic solvent solution of the siloxane resin may be prepared in advance and mixed with the above components. This is because heating may be required when the siloxane resin is dissolved in a solvent. As the solvent, ethanol, isopropanol, isobutanol, propylene glycol monoalkyl ether, diacetone alcohol or the like can be preferably used, but the solvent is not limited thereto.

2) <ii> Component The <ii> component is a curing catalyst for the co-hydrolyzate or co-hydrolyzed condensate of the above-mentioned <i> component for forming a silicone hard coat film, and a basic curing agent and What consists of an acidic control agent is preferable. The basic curing agent promotes the condensation reaction of silanol groups and alkoxysilyl groups of the silicon compound to promote curing by crosslinking, and also develops the hardness of the hard coat layer and the adhesion between the substrate and the acidic control agent is It has the role of controlling the gelation and imparting storage stability of the solution.

  The present invention uses a curing catalyst having a curing activity stronger, that is, a higher basicity than the curing catalyst used in the silicone resin cured film, and preferably appropriate control. Combined with the agent, the coating solution has excellent storage stability, high hardness, excellent scratch resistance, good adhesion, high toughness, and thickness that does not generate cracks even when there is a sudden change in temperature. It has been found that a film can be formed.

  The curing catalyst for the silicone coating composition accelerates the condensation reaction and proceeds with curing by crosslinking, but this alone has a risk of causing gelation during storage. In combination with an acidic control agent, the condensation reaction of silanol groups and alkoxysilyl groups during storage is controlled, and appropriate storage stability of the coating liquid and formation of a cured film are exhibited.

The most prominent strong bases in aqueous solution are alkali metal and tetraalkylammonium hydroxides. The base dissociation constant of the conjugate base A ⁻ from which the acid HA released a proton in an aqueous solution has the following relationship with the acid dissociation constant. The weaker the acid, the stronger the conjugate base.

The base strength of the metal hydroxide is such that the smaller the charge of the metal ion and the larger the ion radius, the weaker the electrostatic force with the hydroxide ion, the stronger the base, and the higher the solubility and solubility product in water. In addition, the base strength increases as the metal electronegativity decreases and the ionic bond strength increases. Therefore, the acid dissociation constant pKa of a metal aqua ion is approximately linear with (e ² / r) where the charge is e and the ion radius is r, and the higher the pKa of the metal aqua ion is, the more difficult it is to hydrolyze. The hydroxide will be a strong base. A strong base refers to a base having a large base dissociation constant. In a narrow sense, a strong base has a degree of ionization close to 1 in an aqueous solution and quantitatively generates hydroxide ions, and has a base dissociation constant of about pKb <0. Those which are water-soluble and are strong bases in an aqueous solution are also called strong alkalis.

The quaternary ammonium cation is a polyatomic ion having a positive charge represented by the molecular formula NR ⁴⁺ . R represents an alkyl group or an aryl group. Unlike ammonium ion NH ⁴⁺ and primary / secondary / tertiary ammonium cations, quaternary ammonium cations are always charged and do not depend on the pH of the solution. Quaternary ammonium salts and quaternary ammonium compounds are salts of quaternary ammonium cations and other anions. Quaternary ammonium compounds are synthesized by alkylation of tertiary amines and this process is called quaternization.

  The curing agent is preferably a basic compound, especially the organic ammonium compound, and is preferably a tetraalkylammonium compound represented by the following general formula (1).

  A characteristic of quaternary ammonium hydroxides is that, unlike alkali metal hydroxides, when they are exposed to a temperature of 100 to 300 ° C., they are easily decomposed into low-boiling amines and alcohols and the basicity disappears. This is considered to contribute to the improvement of the durability of the hard coat film after curing.

[(R ¹ ) (R ² ) (R ³ ) (R ⁴ ) N] ⁺ X ⁻ (1)
Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or a halogenated alkyl group, and X ⁻ represents a hydroxide anion or an organic carboxylic acid. Anion.)

In the above formula, the alkyl group having 1 to 18, preferably 1 to 12 carbon atoms which may be substituted with a halogen atom of R ¹ , R ² , R ³ or R ⁴ includes a methyl group, an ethyl group, and a propyl group. , Butyl group, pentyl group, hexyl group, heptyl group, octyl group, cyclopentyl group, cyclohexyl group and other linear, branched or cyclic alkyl groups, chloromethyl group, γ-chloropropyl group, 3, 3, 3 -Halogenated alkyl groups such as a trifluoropropyl group. Examples of the organic carboxylate anion include formate anion, acetate anion, propionate anion, butyrate anion, valerate anion, and caproate anion.

  Specific examples of such components include, for example, tetra n-propyl ammonium hydroxide, tetra n-butyl ammonium hydroxide, tetra n-pentyl ammonium hydroxide, tetra n-hexyl ammonium hydroxide, tetracyclohexyl ammonium hydroxide, Examples thereof include hydroxides such as tetrakis (trifluoromethyl) ammonium hydroxide, trimethylcyclohexylammonium hydroxide, trimethyl (trifluoromethyl) ammonium hydroxide, and trimethylt-butylammonium hydroxide.

  The basic strength is inversely proportional to the size of the substituent. For example, the basic strength in the case of an alkyl group, that is, the strength of curing activity is methyl group> ethyl group> propyl group> butyl group> Pentyl group> hexyl group> heptyl group> octyl group.

  The curing catalyst of the composition capable of forming a silicone hard coat film laminated with a silicone resin film cured with a base catalyst and an alkoxysilyl group is different, and the base of the latter curing catalyst is different from the basicity of the former curing catalyst. It is necessary to select such an alkyl group for this purpose. Also, generally a weakly active curing system can be made with a weakly curable catalyst and a highly active control agent system, and a small amount of catalyst and a large amount of a control agent system. It can be made with a strong catalyst and a weakly active control agent system, and a large amount of catalyst and a small amount of control agent system. The catalyst having weak curing activity may be an alkylammonium compound other than methyl, and the catalyst having strong curing activity may be a methyl alkylammonium compound. For example, the former basic curing catalyst is tetrabutylammonium acetate, and the latter basic curing catalyst is preferably a compound selected from tetramethylammonium hydroxide, tetramethylammonium acetate, and tetramethylammonium formate. it can.

The control agent having a weak control activity may be a carboxylic acid compound having a high molecular weight, and the control agent having a high activity may be a carboxylic acid compound having a low molecular weight. Carboxylic acid has a carboxyl group and is acidic. Carboxylic acids vary in size, from the smallest carbon formic acid to 16 carbonic palmitic acids, but carboxylic acids without substituents decrease the dissociation of hydrogen ions as the molecular weight increases. That is, the strength as an acid is reduced. The reason for this depends on whether the electron density of the carboxyl group is high or low. The alkyl group is an electron donating group, and the atom or substituent to which the alkyl group is bonded has an electron density increased because the electrons are pressed from the alkyl group. As a result, the electron density of oxygen in the carboxyl group is increased, so that the bond with hydrogen becomes robust. As a result, hydrogen becomes difficult to leave from the carboxyl group, and the acidity decreases. This tendency becomes more conspicuous as the number of carbons constituting the alkyl group increases. Conversely, when an electron withdrawing group is bonded to the carbon adjacent to the carboxyl group of the carboxylic acid, the acidity is increased. For example, chloroacetic acid (CH ₂ Cl-COOH) is stronger than acetic acid. As the number of electron withdrawing groups increases, the acidity becomes stronger.

  Specifically, formic acid, acetic acid, propionic acid, oxalic acid, lactic acid, citric acid, succinic acid, malonic acid, tartaric acid, butyric acid, etc., weak acids that can have a buffering action can be preferably used. desirable.

  The blending amount of the <ii> component is not particularly limited as long as it is an amount effective for curing the silicone of the <i> component. Specifically, the <i> and <ii> components It is preferable that it is 0.0001-30 mass% with respect to solid content of this, More preferably, it is 0.001-10 mass%. If it is less than 0.0001% by mass, curing may be insufficient and the hardness may decrease, and if it is more than 30% by mass, cracks may easily occur in the coating film, and water resistance may decrease. In addition, it is preferable that the quantity ratio of a hardening | curing agent and a control agent is 0.3-3 mol of hardening | curing agents with respect to 1 mol of control agents. If the curing agent is too much, the storage stability may be lowered, and if it is too little, the curability may be lowered.

3) <iii> Organic solvent <iii> The solvent is not particularly limited as long as it dissolves <i> and <ii> components excluding silicon dioxide fine particles, but a highly polar organic solvent is the main solvent. It is preferable that Specific examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol, isobutanol, t-butanol, diacetone alcohol; methyl propyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol Ketones such as dipropyl ether, dibutyl ether, anisole, dioxane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc .; ethyl acetate, propyl acetate, butyl acetate And esters such as cyclohexyl acetate, and one or a mixture of two or more selected from the group consisting of these It can be used.

  As the addition amount of the solvent, it is preferable to use an amount which makes the solid content concentration of the silicone coating composition of the present invention 1-30% by mass, particularly 5-25% by mass. Outside this range, defects may occur in the coating film coated and cured with the composition. If the concentration is less than the above range, sagging, twisting, and spotting are likely to occur in the coating film, and the desired hardness and scratch resistance may not be obtained. If the concentration exceeds the above range, the coating film may be easily brushed, whitened or cracked.

Here, the silicone coating composition of the present invention is formed on the surface of a silicone resin film formed by curing a silicone resin composition containing a base catalyst and a curable silicone having an alkoxysilyl group and / or a silanol group. It is used for the purpose of directly forming a silicone hard coat film. In this case, any silicone resin composition may be used as long as it has an alkoxysilyl group and / or silanol group, and the alkoxysilyl group and / or silanol group undergoes a crosslinking reaction by the action of a base catalyst and cures. A known or commercially available product may be used, and typically, a material containing the <i> and <iii> components described in the above silicone coating composition and a curing catalyst may be used. As the catalyst, a curing catalyst having a curing activity weaker than that of the <ii> component curing catalyst used in the silicone coating composition is used. Particularly, as the curing catalyst, if the curing agent of the curing catalyst of the silicone coating composition is at least one methyl group of R ¹ to R ⁴ in the above formula (1), R ¹ as a curing agent to R Any of ⁴ is an alkyl group having 2 or more carbon atoms. More preferably, the curing agent of the curing catalyst of the silicone coating composition is a compound selected from tetramethylammonium hydroxide, tetramethylammonium acetate, and tetramethylammonium formate, and the base catalyst of the silicone resin composition. The curing agent is tetrabutylammonium hydroxide.

  The silicone coating composition of this invention can obtain the coated article which formed the film by apply | coating and hardening on the silicone resin film by the said silicone resin composition.

  As a method for applying the coating composition, the substrate can be coated by a normal application method. For example, various coatings such as brush coating, spraying, dipping, flow coating, roll coating, curtain coating, spin coating, knife coating, etc. A method can be selected.

  The method for forming the coating film preferably comprises the following steps. A step of applying a conventionally known undercoat layer (silicone resin film of the above-mentioned silicone resin composition) to the substrate as a first layer via a primer layer, if necessary, a step of curing the applied film by air drying or heat curing This is achieved by sequentially performing the step of applying the silicone coating composition of the present invention on the undercoat layer, drying at room temperature, or heating to form the second layer by forming a hard coat layer.

  Moreover, as a base material used here, a plastic molded object or a composite of plastic and ceramics, glass or metal, etc. are mentioned, and it is suitably used for various plastic materials (organic resin base materials), such as polycarbonate, polystyrene, Acrylic resin, ABS resin, vinyl chloride resin and the like are preferable, and polycarbonate resin and the like are particularly preferable.

  Curing after applying the composition of the present invention may be left in the air and air-dried, or may be heated. Although the curing temperature and the curing time are not limited, it is preferable to heat at a temperature lower than the heat resistant temperature of the substrate for 10 minutes to 2 hours. Specifically, it is more preferable to heat at 80 to 145 ° C. for 10 minutes to 2 hours.

  The thickness of each coating film is not particularly limited and may be 0.01 to 100 μm, particularly 0.5 to 60 μm. However, the hardness of the coating film, scratch resistance, long-term stable adhesion, and cracks In order to satisfy that it does not occur, 1 to 30 μm is preferable. The above operation may be repeated to perform overcoating. In particular, the thickness of the undercoat layer is important for protecting the plastic material from ultraviolet rays, and is preferably 5 to 20 μm. If it is less than 0.1 μm, the adhesion to the top layer may not be sufficient, and if it exceeds 100 μm, foaming is likely to occur and the hardness may not be sufficient. Further, in the top layer, if it is less than 0.1 μm, the hardness may not be sufficient, and if it exceeds 100 μm, cracks are likely to occur.

  EXAMPLES Hereinafter, although a synthesis example, a manufacture example, a reference example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following examples, a part shows a mass part and% shows the mass%.

First, a synthesis example of a primer hard coating and a silicone hard coat coating not containing a curing agent is shown below.
1) Production of primer paint [Synthesis Example 1]
<I> Polymer synthesis example 1: Synthesis of primer polymer A 2 liter flask equipped with a stirrer, a condenser and a thermometer was charged with 248 g of diacetone alcohol as a solvent and heated to 80 ° C. under a nitrogen stream.
A monomer mixed solution (2- [2′-hydroxy-5 ′-(2-methacryloxyethyl) phenyl] -2H-benzotriazole (abbreviated as RUVA-93, manufactured by Otsuka Chemical Co., Ltd.) ) 72 g, γ-methacryloxypropyltrimethoxysilane (abbreviated as KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) 80 g, methyl methacrylate (abbreviated as MMA) 248 g, diacetone alcohol (abbreviated as DAA) 600 g) 150 g of a solution prepared by dissolving 3 g of 2,2′-azobis (2-methylbutyronitrile) (abbreviated as V59) as a polymerization initiator in 200 g of diacetone alcohol was added in order.
After reacting at 80 ° C. for 30 minutes, the remaining monomer mixed solution and the remaining polymerization initiator solution were simultaneously added dropwise at 80 to 90 ° C. over 1.5 hours. Furthermore, it stirred at 80-90 degreeC for 5 hours, and obtained the copolymer containing an alkoxy silyl group and an ultraviolet absorptive group.
The content of the ultraviolet-absorbing group unit in this copolymer solution was 18%, and the content of the alkoxysilyl group unit was 20%, but this viscosity was 5,370 mPa · s. Moreover, the weight average molecular weight by GPC analysis on the basis of standard polystyrene was 27,600, and the other solution physical properties are summarized in Table 1. This copolymer solution is designated as UV polymer 1.
(Note) KBM-503: γ-methacryloxypropyltrimethoxysilane RUVA-93: 2- [2′-hydroxy-5 ′-(2-methacryloxyethyl)
Phenyl] -2H-benzotriazole (Otsuka Chemical Co., Ltd.)
MMA: Methyl methacrylate

Composition and physical properties of raw material polymer and paint (1) Synthesis composition and solution physical properties of polymer for primer

[Synthesis Example 2]
<Ii> Primer Synthesis Example 1 Synthesis of Primer Composition A UV polymer 1 was mixed with solvent (DAA, MFDG, EA) and silica sol solution (colloidal silica dispersed in PGMAC (propylene glycol monomethyl ether acetate), trade name: PMA -ST, solid content concentration of 30%, primary particle size of 10 to 15 nm, manufactured by Nissan Chemical Industries, Ltd.) and triethyl orthoformate (OFE) were added to obtain primer composition A. Table 2 summarizes the types and blending amounts of the solvent and the physical properties of the primer composition A solution.
(Note) DAA: diacetone alcohol MFDG: di (propylene glycol) monomethyl ether PGMAC: propylene glycol monomethyl ether acetate EA: ethyl acetate OFE: triethyl orthoformate

(2) Composition composition and solution physical properties of primer composition A

2) Production of silicone hard coat paint [Synthesis Example 3]
<Iii> Synthesis Example 1 Production of Flexibility-Providing Polysiloxane (C) A 2 L three-necked flask equipped with a thermometer, a stirrer, and a cooler was charged with 408 parts of methyltrimethoxysilane and 400 parts of toluene, and 98% methanesulfone. 11 parts of acid was added as a catalyst, and 146 parts of water was added dropwise while keeping the internal temperature at 30 ° C. or lower to hydrolyze methyltrimethoxysilane. After completion of the dropwise addition, the reaction was completed by stirring at room temperature for 2 hours.
Then, the acidic component was neutralized and the produced methanol was distilled off under reduced pressure. After completely removing the neutralized salt by washing twice with water, solvent components such as toluene are removed by removing the solvent component at 105 ° C. under reduced pressure again until the mass loss before and after drying for 3 hours becomes 1.1%. 210 parts of a transparent solid siloxane resin was obtained.
The weight average molecular weight obtained from GPC of this resin was 7.5 × 10 ³ . Moreover, from the results of ²⁹ Si-NMR and IR spectrum of this resin, the average composition formula of this siloxane resin was the following formula (C).
MeSi (OMe) _0.06 (OH) _0.12 (O) _1.41 (C)
(In the formula, Me represents a methyl group.)
It was 75 degreeC when the softening point of this transparent solid resin was measured with the ring and ball type automatic softening point tester based on JISK2207. The physical properties are summarized in Table 3.
This siloxane resin 283 parts was made into siloxane resin solution C of solid content concentration 28% by adding and dissolving 717 parts of isopropanol.

(3) Physical properties of flexible polysiloxane C

2) Synthesis of silicone hard coat paint B [Synthesis Example 4]
Top synthesis example 1
Into a 2 liter flask equipped with a stirrer, a condenser and a thermometer, 381 g of methyltrimethoxysilane was charged and maintained at 20 ° C. while stirring. Here, water-dispersed colloidal silica (Snowtex O (average particle size 15 to 20 nm), A mixed solution of 108 g of Nissan Chemical Industries, Ltd. (containing 20% SiO ₂ ) and 252 g of 0.25N acetic acid aqueous solution was added and stirred at high speed.
Next, after stirring at 60 ° C. for 3 hours, 330 g of cyclohexanone was added, and then methanol and a part of water by-produced at normal pressure were distilled off.
After cooling to room temperature with stirring, 205 g of isopropanol, 400 g of a 28% flexible siloxane resin solution C, and 0.6 g of polyether-modified silicone KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) were added.
The organopolysiloxane solution thus obtained had a viscosity of 6.39 mm ² / s and a weight average molecular weight of 2,500 as determined by GPC analysis. This is designated as silicone hard coat composition B (top agent base).
These physical properties are summarized in Table 4.

(4) Solution physical properties of silicone hard coat paint B

3) Production of curing agent Curing agents having different curing activities were produced by using different basic catalysts, control agents and solvents in the following manner.
(1) Tetrabutylammonium curing agent (low activity)
[Production Example 1]
<I> Production of tetrabutylammonium-acetic acid-based curing agent (TBAH / Ac)
Into a 100 ml flask is charged 54.5 g of isopropyl alcohol (IPA), and 44 g of an aqueous solution of 10% tetrabutylammonium hydroxide is added as a curing catalyst and maintained at 20 ° C. with stirring. The mixture was added and stirred at high speed for 30 minutes.
The clear solution thus obtained had a viscosity of 3.92 mm ² / s, a pH of 6.36, and a remaining heating amount at 150 ° C. for 30 minutes was 2.39%. This is a tetrabutylammonium curing agent (TBAH / Ac).

(2) Production of tetramethylammonium curing agent (high activity)
[Production Example 2]
<I> Production of tetramethylammonium curing agent (TMAH)
A 100 ml flask was charged with 56 g of isopropyl alcohol (IPA), and 44 g of an aqueous solution of 20% tetramethylammonium hydroxide was added as a curing catalyst and stirred.
The clear solution thus obtained had a viscosity of 1.39 mm ² / s, a pH of 14 <, 150 ° C., and a residual heating amount of 30 minutes at 6.15%. This is a tetramethylammonium curing agent (TMAH).

[Production Example 3]
<Ii> Production of tetramethylammonium-acetic acid curing agent (TMAH / Ac) (TMAH / Ac-2)
A 100 ml flask was charged with 50 g of isopropyl alcohol (IPA), 44 g of 20% tetramethylammonium hydroxide aqueous solution was added as a curing catalyst, and maintained at 20 ° C. with stirring. Stir at high speed for minutes.
The clear solution thus obtained had a viscosity of 4.86 mm ² / s, a pH of 8.07, and a remaining heating amount at 150 ° C. for 30 minutes was 14.87%. This shall be tetramethylammonium-acetic acid curing agent (TMAH / Ac). Similarly, the viscosity of a solution containing 3 g of acetic acid was 3.86 mm ² / s, the pH was 14 or more, and the remaining amount of heat at 150 ° C. for 30 minutes was 10.27%. This shall be (TMAH / Ac-2).

[Production Example 4]
<Iii> Manufacture of tetramethylammonium acetate curing agent (TMAH · Ac)
Into a 100 ml flask was charged 14.3 g of isopropyl alcohol (IPA), and 85.7 g of a 15% tetramethylammonium acetate aqueous solution was added as a curing catalyst and control agent.
The transparent solution thus obtained had a viscosity of 2.53 mm ² / s, a pH of 8.77, a residual heating amount of 15.42% at 150 ° C. for 30 minutes. This is a tetramethylammonium acetate curing agent (TMAH · Ac).

[Production Example 5]
<Iv> Production of tetramethylammonium formic acid curing agent (TMAH / Fo)
A 100 ml flask was charged with 52 g of isopropyl alcohol (IPA), 44 g of an aqueous solution of 20% tetramethylammonium hydroxide was added as a curing catalyst and maintained at 20 ° C. with stirring, and 4 g of formic acid was added thereto as a control agent to add 30 g. Stir at high speed for minutes.
The clear solution thus obtained had a viscosity of 4.40 mm ² / s, a pH of 14 or more, and a remaining heating amount at 150 ° C. for 30 minutes was 13.1%. This shall be the top curing agent (TMAH / Fo).
These physical properties are summarized in Table 5.

Physical properties of curing agents

4) Production of liquid composition for coating film [Production Example 6]
The primer composition A of the primer paint was used as an undercoat for the examples. The silicone hard coat paint B was prepared by adding 2.0 g of a curing agent for top (TBAH / Ac, TMAH / Ac) to 100 g of the paint B, respectively, to obtain a base silicone resin composition of Examples and Comparative Examples.
Also, 2.0 g of curing agent for each top (TBAH / Ac, TMAH / Ac, TMAH, TMAH · Ac, TMAH / Fo) is added to 100 g of silicone hard coat paint B, and the silicone coating for lamination of Examples and Comparative Examples is added. A composition was obtained.

[Examples 1-4, Comparative Examples 1-4]
(1) Preparation of base silicone layer coating film A base silicone resin film for laminating a silicone hard coat film was prepared by the following method.
After applying primer composition A to a 0.5 mm polycarbonate resin plate (Iupilon sheet, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) as a cured coating film by a flow coating method and air-drying at room temperature for 20 minutes. And cured at 120 ° C. for 60 minutes.
A silicone resin composition to which a curing agent is added is applied by a flow coating method so as to have a cured coating film thickness of 5 μm, air-dried at room temperature for 20 minutes, and then cured at 120 ° C. for 60 minutes to form a silicone resin film. Formed (underlying silicone layer).

(2) Examples, Reference Examples and Comparative Examples [Examples 1 to 3, Comparative Examples 1 to 3, Reference Example 1]
On the underlying silicone resin film, a silicone coating composition added with a curing agent was applied as a cured coating film to a thickness of 5 μm by a flow coating method, air-dried at room temperature for 20 minutes, and then cured at 120 ° C. for 60 minutes. (Laminated silicone layer).
The coating film thus obtained was evaluated by the following evaluation method. The results of various physical property evaluations are shown in Table 6.

保存安定性評価：○：実用上合格、×：実用上不合格、△条件により使用可能
外観（初期Ｈｚ）評価：◎：０．３より小さい、○：１．５より小さい、
△：３より小さい、×：３以上
密着性評価：○：初期と煮沸ともに１００％、×：初期のみ１００％、
××：初期も１００％でない
硬度（ΔＨｚ）評価：◎：２より小さい、○：１０より小さい、×：１０以上
総合評価：◎：非常に良い、○：実用上合格、×：実用上不合格、△：条件により使用可能

Storage stability evaluation: ○: Practical pass, ×: Practical reject, Δ Applicable appearance (initial Hz) evaluation: ◎: Less than 0.3, ○: Less than 1.5,
Δ: smaller than 3, x: 3 or more Adhesion evaluation: ○: 100% for both initial and boiling, x: 100% for initial only,
XX: Hardness (ΔHz) which is not 100% even at the beginning: A: Less than 2, B: Less than 10, B: More than 10 Overall evaluation: A: Very good, B: Practical pass, X: Practical failure Pass, △: Can be used depending on conditions

As for the reference example, a good coating film could be formed immediately after mixing, but gelation occurred after 1 day at 40 ° C., and the coating film could not be formed. Therefore, this system can be used depending on conditions as in the two-component type.
On the other hand, as in Comparative Example 1, in the absence of a control agent, gelation occurred immediately after mixing, and the coating film properties could not be evaluated.
The plastic polycarbonate resin having the base silicone resin film and the silicone hard coat film (top coat layer) according to the present invention has an excellent appearance, adhesion, and hardness, and is an excellent film as a comprehensive evaluation. .

Evaluation Examples Various physical properties in the examples were measured and evaluated by the following methods.
1) Method of evaluation Evaluation was performed about the film | membrane characteristic (film forming property, external appearance, adhesiveness, hardness) about the polycarbonate resin which has a silicone hard coat film | membrane.

(1) Evaluation of film forming property The appearance of a coating film of a polycarbonate resin film test piece obtained by sequentially curing and laminating a primer layer, a silicone resin film, and a silicone hard coat film was visually observed for cracks.

(2) Evaluation of film appearance The coating film appearance of the laminated test piece is haze meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.), and the haze (denoted as haze, Hz) is less than 0.3. ◎ (very good), when 0.3 or more and less than 1.5 ○ (can be used practically), when 1.5 or more and less than 3 △ (can be used depending on applications and conditions), 3 or more Was evaluated as x (practically unusable).

(3) Evaluation of adhesion characteristics of the membrane to the polycarbonate resin film Initial adhesion is based on JIS K5400, and the test piece is cut with 6 razor blades at intervals of 2 mm vertically and horizontally to make 25 grids, When the commercially available cellophane adhesive tape was closely adhered and then peeled off 90 degrees toward the front, the number of squares (X) remaining without peeling off the coating was examined by X / 25 and expressed as%. Further, as an evaluation of boiling adhesiveness, after immersing the test piece in boiling water for 4 hours, the appearance was visually observed and the adhesiveness test was performed in the same manner as described above.
As the evaluation of adhesion, the results of the initial adhesion test and the boiling adhesion test are both 100% (can be used practically), the initial adhesion test is 100%, but the result of the boiling adhesion test is 100. A case in which the results of the initial adhesion test and the boiling adhesion test were both less than 100% was evaluated as x (not practically usable).

(4) Evaluation of film hardness As a scratch resistance test, a wear wheel CS-10F was attached with a Taber abrasion tester (Taber 5130 Abraser manufactured by Toyo Seiki Co., Ltd.) in accordance with ASTM 1044, under a load of 500 g. The haze value after 500 rotations was measured.
Scratch resistance (%) ΔHz was expressed as (cloudiness value after test) − (cloudiness value before test).
The evaluation of film hardness is
◎ (very good): ΔHz <2.0
○ (Practically usable): 2.0 ≦ ΔHz <10.0
× (Not practically usable): 10.0 ≦ ΔHz

Claims (4)

Silicone coating composition for directly forming a silicone hard coat film on the surface of a silicone resin film formed by curing a silicone resin composition comprising a base catalyst and a curable silicone having an alkoxysilyl group and / or silanol group Because
<I> Co (partial) hydrolyzate or co (partial) hydrolyzed condensate of hydrolyzable silicon compound and silicon dioxide fine particles,
<Ii> A silicone coating composition comprising a curing catalyst having a curing activity stronger than that of the base catalyst of the silicone resin composition, and <iii> an organic solvent. The <ii> component curing catalyst comprises a curing agent of a basic organic compound and a control agent of an acidic organic compound, and the basic organic compound is an ammonium compound represented by the following general formula (1). The silicone coating composition of claim 1.
[(R ¹ ) (R ² ) (R ³ ) (R ⁴ ) N] ⁺ X ⁻ (1)
Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or a halogenated alkyl group, and X ⁻ represents a hydroxide anion or an organic carboxylic acid. Anion.) The curing catalyst of <ii> component comprises a curing agent in which at least one of R ^{1 to} R ⁴ in formula (1) is a methyl group and a control agent for an acidic organic compound, and the base catalyst of the silicone resin composition is The silicone coating composition according to claim 2, comprising a curing agent in which all of R ^{1 to} R ⁴ in formula (1) are alkyl groups having 2 or more carbon atoms and a control agent for an acidic organic compound.   The curing agent of the curing catalyst of the <ii> component is a compound selected from tetramethylammonium hydroxide, tetramethylammonium acetate, and tetramethylammonium formate, and the curing agent of the base catalyst of the silicone resin composition is The silicone coating composition of claim 3 which is tetrabutylammonium hydroxide.