JPH0211611B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photosensitive coating composition, and particularly to a photosensitive coating composition that is tough, flexible, has good adhesion, and has excellent photocurability. In recent years, photosensitive compositions have attracted attention as materials with new curing systems in response to progress in environmental pollution, increased energy costs, and restrictions on energy use. Such photosensitive compositions are often made of polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin, etc., but they generally do not contain volatile organic solvents, so they are not suitable for environmental protection. It is very desirable, and it is also excellent in terms of overall economic efficiency, taking into account various factors such as energy saving and shortening of curing time, so paints,
It is widely applied in printing inks, adhesives, flexible circuit overlays and other coating materials, solder resists for printed circuit boards, etching resists, plating resists, and inks for printed circuits. However, the curing reaction of such photosensitive compositions due to light irradiation such as ultraviolet rays or electron beam irradiation occurs rapidly in an extremely short period of time, which causes distortion inside the cured product and remains as it is. Poor adhesion compared to mold and thermosetting varnishes. On the other hand, adhesion can be improved by sufficiently slowing down the curing speed, but in this case the original feature of shortening the curing time is lost. Furthermore, adhesion is significantly affected by the type of substrate, but commercially available solvent-containing oxidative polymerization ink coatings,
Very few materials have yet been found that have excellent curability and adhesion to metals, glass, synthetic resins, etc., and for this reason, their use is often restricted in the practical application of photosensitive coating materials. Ta. In view of this, attempts have been made to modify the materials of photosensitive compositions, improve the composition, and even add thermoplastic resins and thermosetting resins that do not directly participate in the photocuring reaction. In many cases, the intended purpose cannot be achieved. An object of the present invention is to provide a photosensitive coating composition that is strong, flexible, and has excellent adhesion while maintaining fast curing properties. The present invention provides a photosensitive coating composition comprising an unsaturated urethane prepolymer having two or more terminal groups having a polymerizable ethylenic double bond and a photopolymerization initiator, wherein the prepolymer is an organic polyisocyanate (A), Ethylenically unsaturated compound (B) with active hydrogen, general formula (R ¹ , R ² and R ³ are each an alkylene group having 2 to 4 carbon atoms, l, m and n are each an integer of 1 or more, and the total is 3 to 12) The present invention relates to a photosensitive coating composition characterized in that it contains a prepolymer formed from a compound (C) and, if necessary, a polyol (D). The photosensitive coating composition of the present invention can be used in various applications, such as paints, varnishes, coating materials,
It is useful as a film-forming agent, a textile/leather/wood processing agent, etc. Organic polyisocyanate (A) used in the present invention
Examples include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), tolidine diisocyanate (TODI), xylylene diisocyanate (XDI), naphthylene diisocyanate (NDI), isophorone diisocyanate ( IPDI),
Hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI)
and polyisocyanates such as triphenylmethane triisocyanate and polymethylene polyphenyl isocyanate (PAPI). In the present invention, various types of ethylenically unsaturated compounds (B) having active hydrogen can be used, but representative examples include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, Mono(meth)acrylates of dihydric alcohols such as 1,4-butanediol, diethylene glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol; mono(meth)acrylates of trihydric alcohols such as trimethylolethane, trimethylolpropane, and glycerin; ) acrylate, and di- and tri(meth)acrylates of alcohols having a valence of 4 or more, such as pentaerythritol. Compound (C) of the present invention is tris(2-hydroxyalkyl)isocyanurate and a derivative obtained by reacting this with alkylene oxide. Representative examples of tris(2-hydroxyalkyl)isocyanurate include tris(2-hydroxyethyl)isocyanurate, tris(2-hydroxypropyl)isocyanurate, and the like.
In addition, its derivatives are obtained by reacting alkylene oxides such as ethylene oxide and propylene oxide, and alkylene oxides may be reacted all at once.
One type or two or more types may be reacted in stages.
In the general formula (1), the sum of l, m and n is the sum of 3 to the number of moles of alkylene oxide reacted with the hydroxyl group of tris(2-hydroxyalkyl)isocyanurate. As the number of moles of alkylene oxide added increases, the flexibility and elongation of the resin are further improved. In the present invention, polyol (D) can be used if necessary. As the polyol (D), various polyester polyols, polyether polyols, and other polyols can be used. Examples of polyester polyols include aliphatic dicarboxylic acids having 4 to 20 carbon atoms such as adipic acid, suberic acid, sebacic acid, and brassylic acid, terephthalic acid, and isophthalic acid as acid components, and ethylene glycol, propylene glycol, neopentyl glycol, 1 or more carbon atoms such as hexamethylene glycol
6 aliphatic diols, ether glycols such as diethylene glycol, dipropylene glycol,
Polyester polyols or polycaprolactone polyols containing spiroglycols, N-alkyl dialkanolamines such as N-methyldiethanolamine, etc. as polyol components can be used, and specific examples include polyethylene adipate polyol, polybutylene adipate polyol, and polyethylene. Adipate polyols such as propylene adipate polyol, terephthalic acid polyols (e.g., Toyobo Co., Ltd., product names Vylon RUX, Vylon RV-200L), polycaprolactone polyols (e.g., Daicel Chemical, product names Plaxel 212, Plaxel 220), etc. I can give an example. Specific examples of polyether polyols include polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene polyol, and the like. In addition, other polyols include polycarbonate polyols (e.g., West Germany, Bayer AG, product name Desmofene 2020E), polybutadiene polyols (e.g., Nippon Soda, product names G-1000, G-
2000, G-3000, Idemitsu Petrochemical, product name Poly
bdR-45HT), polypentadiene polyol,
Examples include castor oil-based polyols. The prepolymer in the present invention can be synthesized by various known methods. Typical examples of synthesis are a one-stage reaction method or a stepwise reaction method in which two components are first reacted, followed by a third component. That is, for example, by reacting compounds (A) and (B),
Synthesize a prepolymer of NCO, then compound (C)
and a method of reacting compound (D) if necessary, synthesizing a prepolymer with terminal NCO from compounds (A) and (D),
Next, compound (B) is added and reacted, and then compound (C)
A method in which NCO-terminated prepolymers are synthesized from compounds (A) and (B) and compounds (A) and (D), respectively, and compound (C) is reacted with a mixture of these two types of prepolymers. Examples of how to do this can be given. In addition, since the compound (C) of the present invention has three active hydrogen atoms, it is desirable to employ a stepwise reaction method in order to prevent gelation during synthesis. In producing the prepolymer of the present invention, the proportions of each component can be appropriately determined from a wide range depending on the desired photosensitive coating composition, but usually the ethylenically unsaturated compound (B) having active hydrogen, the general formula (1 ) compounds
The reaction should be carried out in a range where the chemical equivalent ratio of the active hydrogen groups contained in (C) and polyol (D) and the NCO group of compound (A) is 0.9 to 1.4, preferably 0.95 to 1.2. Usually 30-130℃, preferably 40-120℃
It is better to do it with In the present invention, the prepolymer can be synthesized without a solvent, in the presence of an organic solvent, or in the presence of an ethylenically unsaturated compound used as a crosslinking agent, which will be described later. Examples of organic solvents include ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and methyl propionate, ethers such as dioxane and cellosolve acetate,
Other examples include dimethylformamide and dimethyl sulfoxide. In the photosensitive coating composition of the present invention, known prepolymers formed from organic polyisocyanates, polyols, and ethylenically unsaturated compounds having active hydrogen can also be used in combination. However, the compound represented by general formula (1) used in the present invention
The number average molecular weight of the total prepolymer per 1 mole of compound (C) is 800 to 15,000, in particular
It is preferable to set it in the range of 900 to 12,000, and within this range, the above-mentioned properties can be sufficiently exhibited while preventing the possibility of gelation during synthesis. In the present invention, an ethylenically unsaturated compound can be used as a crosslinking agent if necessary when curing the above prepolymer. Various known compounds can be used as the ethylenically unsaturated compound, but representative examples include styrene, vinyltoluene, chlorostyrene, t-butylstyrene,
α-methylstyrene, divinylbenzene, acrylic acid, methacrylic acid, methyl, ethyl, isopropyl, n-butyl, t-butyl, α-ethylhexyl, n-nonyl, n-decyl, lauryl, stearyl ester of acrylic acid or methacrylate etc., n-butoxyethyl, cyclohexyl, phenoxyethyl, tetrahydrofurfuryl, glycidyl, allyl, benzyl, tribromophenyl, 2,3-dichloropropyl, 3-chloro-2-hydroxypropyl, N, etc. of acrylic acid or methacrylic acid. N-dimethylaminoethyl, N,N
- Diethylaminoethyl, Nt-butylaminoethyl ester, etc., ethylene glycol mono(meth)acrylate, propylene glycol mono(meth)acrylate, diethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, molecular weight (hereinafter MW)
) 200-1000 polyethylene glycol mono(meth)acrylate, MW200-1000 polyethylene glycol monomethyl ether mono(meth)acrylate, MW200-1000 polypropylene glycol mono(meth)acrylate,
Polypropylene glycol monomethyl ether mono(meth)acrylate with MW200~1000,
Polyethylene glycol monoethyl ether mono(meth)acrylate with MW200~1000,
MW200-1000 polypropylene glycol monoethyl ether mono(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,3
-propanediol di(meth)acrylate,
1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, glycerin di(meth)acrylate, glycerin tri(meth)acrylate,
trimethylolethane di(meth)acrylate,
Trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide,
Examples include ethylene bisacrylamide, diallyl phthalate, triallyl isocyanurate, dibutyl fumarate, and vinyl acetate. However, if present during the urethanization reaction, ethylenically unsaturated compounds having active hydrogen should be excluded from the above. In the present invention, the ratio of the prepolymer to the ethylenically unsaturated compound is 30:70 by weight.
to 95:5 is preferred, and 50:50 to 80:20 is more preferred. In the present invention, various known compounds can be used as the photopolymerization initiator, such as benzophenone,
Ketone compounds such as p-methylbenzophenone, p-chlorobenzophenone, Michler's ketone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, α-allylbenzoin, α
-Benzoins such as chlorobenzoin, anthraquinone, 2-methylanthraquinone, 1-chloroanthraquinone, p-benzoquinone, 1,4-
Quinones such as naphthoquinone, sulfides such as phenyl disulfide and tetramethylthiuram monosulfide, sulfonyl chlorides such as β-naphthalenesulfonyl chloride and p-chlorobenzenesulfonyl chloride, 2-nitrofluorene, 5-nitroacetic acid Examples include nitro compounds such as naphthene, halogenated hydrocarbons such as tetrabromomethane, thioxanthone such as 2-chlorothioxanthone, and azo compounds such as azobisisobutyronitrile. These photoinitiators are used in an amount of 0.001 to 10% by weight, preferably 0.01 to 5% by weight based on the total amount of the prepolymer and crosslinking agent.
It can be used within the range of A known thermal polymerization inhibitor may be added for the purpose of stably storing the photosensitive coating composition of the present invention. For example, hydroquinone, mono-tert
-Butylhydroquinone, 2,5-di-tert-butylhydroquinone, hydroquinone monomethyl ether, catechol, p-tert-butylcatechol, benzoquinone, 2,5-di-tert-butylbenzoquinone, 2,5-diphenyl-p-benzoquinone , 2,6-di-tert-butyl-p-cresol, and picric acid. It is desirable that these thermal polymerization inhibitors prevent only the thermal polymerization reaction (dark reaction) without inhibiting the photocuring reaction, and therefore the amount added is 0.001% of the total amount of the prepolymer and crosslinking agent. A range of 2.5% by weight, preferably 0.005% to 1% by weight is desirable. The photosensitive coating composition of the present invention can be cured by a known method, for example, at a wavelength of 200 to 700 nm.
It is appropriate to use an active light source of . The active light source may be appropriately selected depending on the type of photopolymerization initiator, and for example, sunlight, low pressure, high pressure or ultra-high pressure mercury lamp, carbon arc lamp, xenon lamp, tungsten lamp, etc. can be used. Further, in the present invention, other curing means may be employed, such as heat curing, that is, curing using radiation mainly consisting of thermal energy such as infrared rays, high frequency waves, or microwaves, or curing using ionizing radiation such as electron beams or gamma rays. can. Suitable polymerization initiators in such cases include, for example, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, hydroperoxides such as cumene hydroperoxide and tert-butyl peroxide, di-
Dialkyl peroxides such as tert-butyl peroxide and dicumyl peroxide, tert
Examples include peroxy esters such as -butyl peroxylaurate and tert-butyl peroxybenzoate, and azo compounds such as azobisisobutyronitrile. Further, polymerization accelerators such as metal soaps such as cobalt and manganese for the above-mentioned ketone peroxides, or reducing amines for the above-mentioned hydroperoxides can also be used. Furthermore, when using high-energy ionizing radiation that has the effect of being absorbed by substances such as the above-mentioned electron beams and γ-rays and emitting secondary electrons, it may be used alone or in combination with irradiation from the active light source. does not require the addition of an initiator, but may contain a photopolymerization initiator or a thermal polymerization initiator as described above. Furthermore, the compositions of the invention may contain colorants and other additives commonly used in photosensitive coating compositions of this type. By introducing an isocyanurate ring into the molecule, the photosensitive coating composition of the present invention not only significantly improves curability and adhesion, but also has excellent toughness and flexibility, and improved heat resistance. Provides a coating that A detailed explanation will be given below with reference to synthesis examples and examples. Synthesis Example 1 138g of 2,4-TDI was placed in a reactor equipped with a stirrer and heated to 80°C, and a mixture of 396.5g of polyethylene adipate polyol with a molecular weight of 1000 and 0.57g of dibutyltin dilaurate was gradually added, and the mixture was heated to 90°C.
2-hydroxyethyl acrylate (ethylene glycol monoacrylate), 0.07 g of dibutyltin dilaurate, and hydroquinone.
0.12 g of the mixture was gradually added dropwise, and the mixture was reacted for 2 hours and 30 minutes while maintaining the same temperature. Tris here (2-
Hydroxyethyl) isocyanurate/3PO (propylene oxide 3 mole adduct, same description below)
After heating 57.5 g to 50°C, it was gradually added dropwise to obtain urethane prepolymer (1). Synthesis Example 2 IPDI instead of 2,4-TDI in Synthesis Example 1
A urethane prepolymer (2) was obtained in the same manner as in Synthesis Example 1, except that polybutylene adipate polyol having a molecular weight of 1000 was used instead of polyethylene adipate polyol. Synthesis Example 3 In Synthesis Example 1, 2-hydroxypropyl methacrylate was used instead of 2-hydroxyethyl acrylate, and tris(2-hydroxyethyl)
Urethane prepolymer (3) was obtained in the same manner as in Synthesis Example 1 except that tris(2-hydroxyethyl)isocyanurate 3EO was used instead of isocyanurate 3PO. Synthesis example 4 130.1g of 2,4-TDI in a reactor equipped with a stirring device
Pour in and warm to 70℃, and add 97.2g of 2-hydroxypropyl acrylate and 0.33g of dibutyltin dilaurate.
After gradually dropping a mixture of 0.24 g of tris(2-hydroxyethyl)isocyanurate and 0.24 g of hydroquinone and reacting for 3 hours, 108.4 g of tris(2-hydroxyethyl)isocyanurate.
g and reacted for 2 hours to form a urethane prepolymer.
(4) was obtained. Example 1 To 100 parts by weight of the prepolymer (1) obtained in Synthesis Example 1, 2.5 parts by weight of benzoin isopropyl ether, 20 parts by weight of styrene, 18 parts by weight of 2-hydroxypropyl methacrylate, and 8 parts by weight of tetraethylene glycol diacrylate. was added to obtain a photosensitive composition. Thickness after surface degreasing of this photosensitive composition
After applying it to a thickness of 10μ on a 50μ steel plate using an applicator, it was irradiated with ultraviolet light from a distance of 15cm using a 1KW high-pressure mercury lamp to obtain a test piece. curing time,
The physical properties of the coating film are shown in Table 1. The physical properties of the coating film are JIS
Measured in accordance with 5400. Example 2 To 100 parts by weight of the prepolymer (2) obtained in Synthesis Example 2, 2.2 parts by weight of benzoin methyl ether,
A photosensitive composition was obtained by adding 22 parts by weight of styrene, 15 parts by weight of 2-hydroxyethyl acrylate, and 7 parts by weight of diethylene glycol diacrylate. A coating film was formed in the same manner as in Example 1 using this photosensitive composition. The curing time and physical properties of the coating film are shown in Table 1. Example 3 To 80 parts by weight of the prepolymer (3) obtained in Synthesis Example 3 and 20 parts by weight of the prepolymer (4) obtained in Synthesis Example 4, 2 parts by weight of benzoin methyl ether,
A photosensitive composition was obtained by adding 20 parts by weight of styrene, 12 parts by weight of diethylene glycol monomethacrylate, and 5 parts by weight of nonaethylene glycol diacrylate. A coating film was formed in the same manner as in Example 1 using this photosensitive composition. The curing time and physical properties of the coating film are shown in Table 1. Comparative Example 1 128.9g of 2,4-TDI in a reactor equipped with a stirring device
After heating to 80℃ and gradually adding a mixture of 370.4g of polyethylene adipate polyol with a molecular weight of 1000 and 0.47g of dibutyltin dilaurate,
℃ and reacted for 3 hours, then cooled to 70℃ and added 96.3 g of 2-hydroxyethyl methacrylate.
A mixture of 0.12 g of dibutyltin dilaurate and 0.24 g of hydroquinone was gradually added dropwise and reacted for 3 hours while maintaining the same temperature to obtain urethane prepolymer (5). The thus obtained urethane prepolymer (5) 100
Benzoin methyl ether 2.5 parts by weight
25 parts by weight of styrene, 15 parts by weight of 2-hydroxypropyl methacrylate, and 10 parts by weight of diethylene glycol diacrylate were added to obtain a photosensitive composition. A coating film was formed in the same manner as in Example 1 using this photosensitive composition. The curing time and physical properties of the coating film are shown in Table 1. Comparative Example 2 IPDI instead of 2,4-TDI in Comparative Example 1
A urethane prepolymer (6) was obtained in the same manner except that polypropylene glycol (molecular weight 700) was used instead of polyethylene adipate polyol. Urethane prepolymer (6) thus obtained 100
A photosensitive composition was obtained by adding 2.3 parts by weight of benzoin methyl ether, 22 parts by weight of styrene, 18 parts by weight of 2-hydroxyethyl methacrylate, and 5 parts by weight of tetraethylene glycol diacrylate. A coating film was formed in the same manner as in Example 1 using this photosensitive composition. The curing time and physical properties of the coating film are shown in Table 1.

【table】

[Table] Shows the extrusion depth.

Claims (1)

[Scope of Claims] 1. A photosensitive coating composition comprising an unsaturated urethane prepolymer having two or more terminal groups having a polymerizable ethylenic double bond and a photopolymerization initiator, wherein the prepolymer is an organic polyisocyanate.
(A), ethylenically unsaturated compound with active hydrogen
(B), general formula (R ¹ , R ² and R ³ are each an alkylene group having 2 to 4 carbon atoms, l, m and n are each an integer of 1 or more, and the total is 3 to 12) A photosensitive coating composition comprising a prepolymer formed from a compound (C) and optionally a polyol (D). 2 n of total prepolymer per mol of compound (C)
800 to 15,000. 3. The composition according to claim 1, wherein l, m and n are each integers of 2 to 3.