JPH07166131A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition giving a coating film free from interference fringe and exhibiting uniform reflection color when applied to a plastic lens having high refractive index by compounding a specific organic silicon compound and a specific composite sol. CONSTITUTION:This coating composition is produced by compounding (A) an organic silicon compound of formula (R<1> is a 4-14C organic group having functional group or unsaturated double bond; R<2> is a 1-6C organic group or a halogenated organic group; R<3> is a 1-4C alkyl an acyl, etc.; (a) and (b) each is 0 or 1; a+b is 1 or 2) or its hydrolyzed product (e.g. gamma- glycidoxypropyltrimethoxysilane and methyltrimethoxysilane) with (B) a titanium dioxide composite so (preferably having particle diameter of 5-100mum) produced by coating colloidal dispersed titanium dioxide with a composite sol of tin dioxide and tungsten trioxide and, as necessary, (C) a curing catalyst (preferably an Al chelate compound such as aluminum acetylacetate) and (D) a solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating composition for a plastic molding.

[0002]

2. Description of the Related Art Plastic moldings are widely used in various fields by taking advantage of their advantages such as light weight, easy workability and impact resistance, but on the other hand, they have insufficient hardness and are easily scratched. It has a drawback that it is charged with electricity, adsorbs dust, and has insufficient heat resistance, so it can be used as an inorganic glass molded product for use as a spectacle lens or window material that is expected to be used. In comparison, it is not always satisfactory in practical use.

Therefore, it has been proposed to apply a protective coat to the plastic molded article in order to compensate for such weak points. In this proposal, "a coating composition containing an organosilicon compound or a hydrolyzate thereof as a main component (resin component or film-forming component)" that is expected to give a hard coating film close to an inorganic system (for example, JP-A-52-11261), and this technology has been put to practical use for spectacle lenses.

However, in practice, even in the case of this coating composition, the scratch resistance (scratch resistance) is not yet sufficient, so that a silica sol dispersed in a colloidal form has been proposed (see, for example, Japanese Patent Application Laid-Open No. S60-18753). 53-111
No. 336), this technique is also put to practical use for spectacle lenses. By the way, in general, most of plastic spectacle lenses have been manufactured by casting polymerization of a monomer called diethylene glycol bisallyl carbonate. However, this lens has a refractive index of about 1.50. However, since the refractive index of the glass lens is lower than 1.52, the lens for nearsightedness has a drawback that the edge thickness is large, which is a main factor disliked by the wearer.

Therefore, development of a monomer having a higher refractive index than that of diethylene glycol bisallyl carbonate has been promoted, and for example, JP-A-55-13747 and JP-A-56.
Various monomers disclosed in JP-A-166214, JP-A-57-23611 and JP-A-57-54901 and polymers using the same have been proposed, and at present, n _e =
1.54 to 1.67 medium to high refractive index plastic lenses have been commercially available.

These lenses are also coated with the above coating composition containing silica sol.

[0007]

However, the conventional coating composition containing silica sol has a problem that interference fringes are visible in the coating film and the appearance of the lens is poor. Further, in general, an antireflection film (consisting of a multilayer structure film of an inorganic oxide coating film based on the optical interference theory) is often disposed on the coating film of the lens, and in this case, a reflection color (green However, there is also a problem in that the color tone varies depending on the position of the lens surface, resulting in uneven color tone.

Therefore, according to the present invention, n _e = 1.54 to 1.
It is an object of the present invention to provide a coating composition for a 67 medium to high refractive index plastic molded article, which solves the drawbacks of the prior art and gives a coating film in which no interference fringes are visible in the coating film and the reflection color is uniform. Has an aim.

[0009]

The present invention is intended to solve the above-mentioned problems by: (a) General formula: R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (wherein , R ¹ is a functional group or an organic group having 4 to 14 carbon atoms having an unsaturated double bond, R ² is an organic group having 1 to 6 carbon atoms or a halogenated organic group, and R ³ is a carbon number. 1 to 4 alkyl groups, alkoxyalkyl groups or acyl groups, a and b are each independently 0 or 1, and a + b is 1 or 2). A compound or a hydrolyzate thereof; (b) a colloidally dispersed titanium dioxide and a composite sol of tin dioxide and tungsten trioxide that coats it; (c) a curing catalyst; and (d) a solvent; Provided is a coating composition characterized by being blended.

The composition of the present invention will be described in more detail below. The compounds represented by (a) an organic silicon compound and hydrolyzate thereof above general formula include a wide range of things, but suitable one is used in the present invention, R ¹
Is a polyvalent or reactive functional group or unsaturated 2
Organic groups with heavy bonds come into consideration. In this case, the functional groups include appropriate groups such as oxygen-containing groups and nitrogen-containing groups.

Examples of R ¹ having an epoxy group as a functional group include the following.

[0012]

[Chemical 1]

(In the formula, R ⁴ is an alkyl group or alkoxyalkyl group having 1 to 4 carbon atoms or an acyl group, R ⁵ is a hydrocarbon group having 1 to 6 carbon atoms or a halogenated hydrocarbon group, R ⁵ is
⁶ is hydrogen or methyl group, m is 2 or 3, p is 1 to 6, q
Is 0 to 2. )

[0014]

[Chemical 2]

(R ⁷ is an alkyl group or alkoxyalkyl group having 1 to 4 carbon atoms or an acyl group, and R ⁸ is 1 carbon atom
~ 4 hydrocarbon groups or halogenated hydrocarbon groups, 1 is 2 or 3, and r is 1 to 4. ) All the compounds represented by the above general formula have an epoxy group, and thus are also called epoxysilane. Specific examples of this epoxysilane include, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyldimethoxyethoxysilane, γ-glycidoxypropyltriacetoxysilane. , Γ-glycidoxypropylmethyldimethoxysilane, γ-glycyloxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl)
Examples thereof include ethyltriethoxysilane.

Further, among the compounds represented by the above general formula, examples in which R ¹ has an epoxy group as a functional group (including those in which a = 0) include alkoxy group, vinyl group and acyl group. , Those having an amino group, a halogen atom, a mercapto group, and the like, for example, the following.
Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyldimethoxyethoxysilane, γ-methacryloxypropyltrimethoxysilane, aminomethyltrimethoxysilane, 3-aminopropyltrisilane Methoxysilane, 3-aminopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc. Of various trialkoxysilanes, triacyloxysilanes or trialkoxyalkoxysilane compounds.

All of the above exemplified compounds are examples of trifunctional (a + b = 1) having three OR ³ groups bonded to the Si atom, but bifunctional having two OR ³ groups (a + b = 2). Of course, the corresponding compounds of can also be used. Examples of difunctional corresponding compounds include dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, and dimethyldiethoxysilane.

These compounds may be used alone or in combination of two or more depending on the purpose.
Particularly, when a bifunctional compound is used, it is preferably used in combination with a trifunctional compound. When used together, 2> a + b> 1 on average. Further, it is also possible to use a compound corresponding to a tetrafunctional compound of a + b = 0. Examples of corresponding tetrafunctional compounds include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, t-butyl silicate, sec-butyl silicate and the like.

The above compounds may be used as they are, but it is also effective to use them as a hydrolyzate for the purpose of increasing the reaction rate and lowering the curing temperature. When two or more compounds having the same functional number are used in combination among two to four functional compounds, or when two or more compounds having different functional numbers are used in combination, they may be used in combination after hydrolysis, or Co-hydrolysis may be carried out in combination before. H by hydrolysis
The alcohol that becomes OR ³ is liberated and the above general formula (I)
Is a corresponding silanol: become. This silanol quickly undergoes dehydration condensation,
Become an oligomer. After the hydrolysis, the reaction may be left for 1 to 24 hours (curing) so that the reaction proceeds sufficiently. (B) Titanium dioxide composite sol In the present invention, a composite sol in which colloidally dispersed titanium dioxide and the periphery thereof are coated with a composite sol of tin dioxide and tungsten trioxide is used. The proportion of titanium dioxide and the composite sol of tin dioxide and tungsten trioxide is 2 to 100 parts by weight of the composite sol of tin dioxide and tungsten trioxide with respect to 100 parts by weight of titanium dioxide.

Titanium dioxide sol dispersed in colloidal form,
The tin dioxide sol, the tungsten trioxide sol, and the composite sol itself of titanium dioxide, tin dioxide and tungsten trioxide are known, and some of them are commercially available. Titanium dioxide sol has a high refractive index and is preferable, and it exists as a sol by itself, but as an essential property of the substance, it cannot stably exist with the organosilicon compound of component (a) or its hydrolyzate. Further, the coating composition formed of the component (a) and titanium dioxide sol has a problem in water resistance. On the other hand, the composite sol of tin dioxide and tungsten trioxide has a relatively high refractive index, exists as a sol by itself, and can stably exist with the component (a). However, the coating composition formed of the composite sol of the component (a), tin dioxide and tungsten trioxide is not sufficiently high in refractive index.

Therefore, in the present invention, titanium dioxide and
By using the composite sol of the composite sol of tin dioxide and tungsten trioxide, it is possible to compensate for the defects of both and to bring out the preferable properties. That is, it is possible to obtain a coating composition having a high refractive index, which is stable with the component (a), has no problem in water resistance. The ratio of titanium dioxide and the composite sol of tin dioxide and tungsten trioxide is 2-100 parts by weight of the composite sol of tin dioxide and tungsten trioxide with respect to 100 parts by weight of titanium dioxide in order to make the best use of their respective advantages and to make up for the drawbacks. , Preferably 5 to 50 parts by weight are used. If the ratio is smaller than this, the stability when mixed with the component (a) is insufficient, and if the ratio is larger than this, there is a problem in the refractive index of the coating composition.

The particle size of the sol is 1 to 200 mμ, and especially 5 to
It is preferably 100 mμ. If it is smaller than this, the production is difficult, the stability of the sol itself is poor, and the effect is small.
If it is larger than this, the stability of the coating composition, the transparency and smoothness of the coating film are deteriorated. The sol is a colloidal solution in which fine particles of titanium dioxide and a composite sol of tin dioxide and tungsten trioxide are dispersed in water or an organic solvent or a mixed solution of both, and by adding an appropriate alkali, particularly an organic amine. , Stabilized ones are useful. (C) Curing Catalyst The curing catalyst is used, if necessary, in order to shorten the time for polymerizing the component (a) to form a coating film having a three-dimensional network structure. However, those which impair the stability of the coating composition are not preferred. For example, the following is used as the curing catalyst. <Amines> Monoethanolamine, diethanolamine, isopropanolamine, ethylenediamine, isopropylamine, diisopropylamine, morpholine,
Triethanolamine, diaminopropane, aminoethylethanolamine, dicyandiamide, triethylenediamine, 2-ethyl-4-methylimidazole. <Various metal complex compound> general formula: AlX _n Y _3-n (wherein, X is OL (L is a lower alkyl group), Y is formula M ¹
COOCH ₂ COM ² (M ¹ and M ² are lower alkyl groups), and at least one selected from ligands derived from M ¹ COCH ₂ COOM ² , and n is 0 or 1 or 2. The aluminum chelate compound shown.

Particularly useful chelate compounds are aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate and aluminum-di-n from the viewpoint of solubility, stability and catalyst curing.
-Butoxide-monoethylacetoacetate, aluminum-di-iso-propoxide-monomethylacetoacetate and the like.

Besides, there are chromium acetylacetonate, titanyl acetylacetonate, cobalt acetylacetonate, iron (III) acetylacetonate, manganese acetylacetonate, nickel acetylacetonate, indium acetylacetonate and the like. Further, as other metal complex compounds, metal complex compounds represented by the general formula: M [CH ₂ N (CH ₂ COO) ₂ ] N a _c (wherein M is Zn, M
n, Mg, Fe, Cu, Co, Ca, Bi, Al, and c is 1 or 2) and the like. <Metal alkoxide> Aluminum triethoxide, aluminum tri-n-propoxide, aluminum tri-n-butoxide, tetraethoxytitanium, tetra-n
-Butoxy titanium, tetra-i-propoxy titanium. <Organic metal salt> Sodium acetate, zinc naphthenate, cobalt naphthenate, tin octylate. <Perchlorate> Magnesium perchlorate, ammonium perchlorate. <Organic acid or its anhydride> Malonic acid, succinic acid, tartaric acid, adibic acid, azelaic acid, maleic acid, O-phthalic acid, terephthalic acid, fumaric acid, itaconic acid, oxaloacetic acid, maleic anhydride, succinic anhydride , Itaconic anhydride, 1,2-dimethylmaleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, naphthalic anhydride. <Lewis acid> Ferric chloride, aluminum chloride. <Metal halide> Stannous chloride, stannic chloride, tin bromide, zinc chloride, zinc bromide, titanium bromide, titanium tetrachloride, thallium bromide, germanium chloride, hafnium chloride, lead chloride, lead bromide .

For example, the curing catalysts exemplified above may be used as a mixture of two or more kinds without being used alone. In particular, when the component (a) is an epoxy group, one that also serves as a ring-opening polymerization catalyst may be used. Above all, aluminum chelate compounds are one of the preferred catalysts. (D) Solvent The solvent is used as necessary to make the coating composition liquid or to reduce the viscosity. For example,
Water, lower alcohol, acetone, ether, ketone, ester and the like are used. In the coating composition of the present invention, the component (b) is used in an amount of 10 to 400 parts by weight (solid content), preferably 50 to 300 parts by weight (solid content) per 100 parts by weight of the component (a) (solid content). However, per 100 parts by weight (solid content) of the components (a) and (b),
It is suitable to use 0.00001 to 20 parts by weight of the component (c). The component (d) is used in an appropriate amount depending on the viscosity of the composition.

In addition to the above components (a) to (d), if necessary, for example, for the purpose of improving the adhesiveness with the plastic base material (molded product) on the coated side, improving weather resistance, and the like. Alternatively, various additives may be used in combination for the purpose of improving the stability of the coating composition. Examples of additives are pH adjusters, viscosity adjusters, leveling agents, matting agents, dyes, pigments, stabilizers, UV absorbers, and antioxidants.

In addition, an epoxy resin and other organic polymers may be used in combination for the purpose of improving the dyeability of the coating film. Epoxy resins are widely used for paints and casting, polyolefin-based epoxies, cyclopentadiene oxide, cyclohexene oxide, or alicyclic epoxy resins such as polyglycidyl ester, polyglycidyl ether, epoxidized vegetable oil, novolak type. There are epoxy novolacs composed of phenolic resin and epichlorohydrin, and further copolymers of glycidyl methacrylate and methyl methacrylate. Examples of other organic polymers include polyols, fiber resins, melamine resins and the like.

Various surfactants may be used in combination with the coating composition for the purpose of improving the flow during coating, improving the smoothness of the coating film, and lowering the coefficient of friction of the coating film surface. In particular, a block or graft copolymer of dimethyl siloxane and alkylene oxide, and a fluorine-based surfactant are effective. In some cases, an inorganic filler such as silica sol or diamond fine particles may be used in combination within the range not impairing the object of the present invention.

The composition of the present invention as described above is particularly applied to plastic moldings. As the molded product, for example, polymethyl methacrylate and its copolymer, acrylonitrile-styrene copolymer, polycarbonate,
The composition of the present invention is applicable to cellulose acetate, polyvinyl chloride, polyethylene terephthalate, epoxy resin, unsaturated polyester resin, polyurethane resin, CR-39 polymer and the like.

The shape of the molded product is not particularly limited, and the composition of the present invention can be applied to lumps, wires, films and the like. From the function of the molded product, the composition of the present invention is applied to optical products, particularly camera lenses, spectacle lenses, reflecting mirrors, prisms and the like. In particular, the compositions of this invention, n _e =
It is useful as a scratch-preventing film for a "glass lens" formed of a resin having a medium to high refractive index of 1.54 or more.

The composition of the present invention can be applied to not only plastic molded articles but also inorganic glass, wood, metal articles and the like. As a coating means, a usual coating method such as brush coating, dipping, roll coating, spray coating and flow coating can be used. Furthermore, after the composition of the present invention is applied to a mold, a raw material to be a base material molded product is cast-polymerized to mold a plastic molded product, or after the composition of the present invention is applied to a molded product, it is still cured. Adhere the surface of the coating film that is not in contact with the mold,
Then, the coating film can be cured.

After coating, the coating composition of the present invention is often heated and cured to obtain a hard coating film. A sufficient effect can be obtained at a heating temperature of about 50 to 200 ° C, preferably 80 to 140 ° C. The thickness of the coating film is generally 0.3 to 30 µ after drying, preferably 0.
It is sufficient if it is 5 to 10 μm.

[0033]

The coating composition of the present invention comprises a combination of specific components as described above, and the coating film produced is transparent and has excellent hardness, particularly scratch resistance, which is a problem of plastic molded articles. Since it does not cause deterioration of appearance due to scratches, and significantly suppresses the generation of interference fringes of the coating film and unevenness of reflected color, which was inevitable in the past, it has a remarkable commercial value as an eyeglass lens. It provides high moldings.

Hereinafter, the present invention will be described more specifically by way of examples. Of course, the present invention is not limited to the following examples.

[0035]

Example 1 (1) Preparation of Preliminary Composition A: A reaction vessel equipped with a rotor was charged with 248 parts by weight of γ-glycidoxypropylmethyldiethoxysilane and vigorously stirred using a magnetic stirrer. While stirring, 36 parts by weight of 0.05 N hydrochloric acid aqueous solution was added at once.

Immediately after the addition, the solution was a heterogeneous solution, but it became a uniform, colorless and transparent solution with heat generation in a few minutes. The stirring was continued for further 1 hour to obtain a hydrolyzate corresponding to the component (a). To the obtained hydrolyzate, after adding 56.6 parts by weight of ethanol and 53.4 parts by weight of ethylene glycol as the component (d), 4.7 parts by weight of aluminum acetylacetonate as the component (c) were added, A preliminary composition A was prepared. (2) Preparation of preliminary composition B: γ-glycidoxypropyltrimethoxysilane 21 was placed in a reaction vessel equipped with a rotor.
2.4 parts by weight were charged and the temperature inside the container was kept at 10 ° C.
While stirring vigorously using a magnetic stirrer,
48.6 parts by weight of 0.01N aqueous hydrochloric acid solution was gradually added dropwise. When the cooling was stopped immediately after completion of the dropping, a uniform, colorless and transparent solution-like hydrolyzate corresponding to the component (a) was obtained.

The resulting hydrolyzate contained 77.1 parts by weight of ethanol and 3 parts of ethylene glycol as the component (d).
After adding 7.7 parts by weight, 7.65 parts by weight of aluminum acetylacetonate as the component (c) was added and sufficiently mixed and dissolved to prepare a preliminary composition B. (3) Preparation of coating composition: Preliminary compositions A and B prepared in (1) and (2) above were placed in a glass container as shown in Table 1 below.
Weigh out the stated parts by weight (not solids), pour in
There, commercially available titanium dioxide and a composite sol of a composite sol of tin dioxide and tungsten trioxide (methanol dispersion sol,
Average particle size: 10 to 15 mμ, ratio of titanium dioxide and composite sol of tin dioxide and tungsten trioxide: 100 parts by weight / 40 parts by weight, solid content 20%, 200 parts by weight (not solid content), silicone type 0.45 parts by weight of a surfactant was added and sufficiently stirred and mixed to prepare a uniform, colorless and transparent solution-like coating composition. (4) Application: A commercially available polyurethane spectacle lens having a refractive index n _e = 1.67 is prepared, and a dipping method (pulling speed 1
0 cm / min) and apply the above coating composition at 10
Heat treatment was performed at 0 ° C. for 2 hours to make the coating film effective. (5) Evaluation: The lens with the cured coating film obtained in (4) above was subjected to the following test to evaluate the performance of the coating film. <Rubbing resistance test> The surface of the coating film was rubbed with steel wool # 0000 to evaluate scratch resistance. The evaluation was performed as follows.

◎ …… No scratches even when strongly rubbed. ○ …… Slightly scratched with strong friction. × …… Scratches even with weak friction. Incidentally, the evaluation of the lens without a coating film was x. <Appearance> A general-purpose antireflection film was formed on the coating film cured in the above (4) by a vacuum deposition method, and the unevenness of the reflection color was evaluated by visual observation as follows.

⊚: Uneven reflection color. ○: Some reflection color unevenness. ×: The reflection color is significantly uneven. <Adhesion> Make 100 squares on the coated surface of the lens having a cured coating with a knife to put a 1 mm-long cut line in the vertical and horizontal directions, and then make cellophane adhesive tape (trade name "Cellotape"). Nichiban Co., Ltd.) was strongly attached. By holding one end of the tape in the hand and rapidly peeling it in the direction of 90 degrees, it was examined how many squares of the coating film were peeled off. The number X of peeled squares is used as the numerator and expressed as X / 100. The smaller X, the better the adhesion. <Dyeability> A lens having a cured coating film is treated with a disperse dye (red,
(Yellow and blue three-color mixture) It was immersed in a bath at 90 ° C. for 30 minutes, and the degree of dyeing was measured by light transmittance.

The results of the above evaluations are shown in Table 1. As is clear from Table 1, the characteristics of the coating films of Examples were extremely excellent. Comparative Example 1 In Example, instead of a composite sol of titanium dioxide and a composite sol of tin dioxide and tungsten trioxide, a commercially available silica sol (methanol dispersion sol, average particle size: 13 ± 1) was used.
The coating composition of this example was prepared and evaluated in substantially the same manner as in the example except that mμ, solid content 20%) was used. Comparative Example 2 In Example, instead of the composite sol of titanium dioxide and the composite sol of tin dioxide and tungsten trioxide, a commercially available antimony pentoxide sol (average particle size: 15 mμ, solid content 2) was used.
The coating composition of this example was prepared and evaluated in substantially the same manner as the example except that 0%) was used.

The results of the above evaluations are shown in Table 1.

[0042]

[Table 1]

[0043]

As described above, according to the present invention, a coating composition having the following features can be obtained. (1) When a hard coating film is formed by applying it on a medium to high refractive index plastic spectacle lens, and an antireflection film is formed thereon, there is no unevenness in the reflection color.

(2) The coating film is excellent in scratch resistance, surface hardness, abrasion resistance, flexibility, transparency, heat resistance, water resistance and the like. (3) The elongation of the coating film is large, and the risk of cracking on the surface of the coating film is extremely small even if the substrate is bent. (4) Shrinkage during curing is small, and problems such as curling are small when applied to a thin film.

(5) The antistatic property of the coating film is excellent, and dirt is relatively hard to attach. (6) The coating film is dyed with a disperse dye. (7) The surface reflectance of the coating film is high. (8) The adhesion of the antireflection film, the metal vapor deposition film, etc. to the coating film is good. (9) The sliding property of the coating film surface is good (friction coefficient is low).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Konishi 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Inside Nikon Corporation (72) Inventor Toru Yatsushiro 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Stock company Nikon

Claims (1)

[Claims] 1. (a) General formula: R ¹ _a R ² _b Si (OR
³ ) _{4- (a + b)} (In the formula, R ¹ is a functional group or an organic group having an unsaturated double bond and having 4 to 14 carbon atoms, and R ² is an organic group having 1 to 6 carbon atoms or a halogen. Organic group, R ³ is an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group or an acyl group, a and b are each independently 0 or 1, and a + b
Is 1 or 2) or a hydrolyzate thereof; (b) a colloidally dispersed titanium dioxide and a composite sol of tin dioxide and tungsten trioxide which coats the titanium dioxide; A coating composition comprising (c) a curing catalyst; and (d) a solvent.