JP2543903B2 - Active energy ray curable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an active energy ray-curable composition.

[Prior Art] The method of coating a paint to give a special function such as surface protection or water / oil repellency of various base materials such as metallic inorganic materials, plastics, wood and paper is old. Used from. As a method for curing a coating film, a curing method by heating and a curing method by irradiation with active energy rays have been conventionally known. Compared with the former, the latter has the advantages that the time required for curing is shorter, the coating line occupies a smaller area, and there is no limitation on the substrate because heating is not required. It is widely used for coating various base materials, and its application is also being actively investigated in the fields of optical fiber coating, electronic parts, and special coatings such as electric wires.

The conventionally used active energy ray-curable composition has a main chain structure such as polyester, acrylic copolymer, polyurethane, epoxy polymer, silicone polymer or polyamide as an oligomer component forming the skeleton of the coating film. As a polymerizable cross-linking site, an α, β-olefinic unsaturated bond at the terminal or side chain is used as a main component, and if necessary, a low-viscosity unsaturated monofunctional or polyfunctional compound that is compatible with it. It is composed of a functional monomer. These conventionally used active energy ray cured product compositions have a problem particularly in weather resistance, and none of them can withstand outdoor use sufficiently.

It is generally known that the performance of a coating film formed from a coating composition greatly differs depending on the structure of the skeleton-forming oligomer which is the main component. Therefore, it is considered that when the skeleton-forming oligomer has a structure having good weather resistance, an active energy ray-curable composition having good weather resistance can be obtained.

As a coating composition having good weather resistance, a solvent-soluble fluoropolymer as found in JP-A-57-3417, JP-A-59-189108, JP-A-60-67518 and the like is used in the above polymer. A heat-curable coating composition is known in which a hydroxyl group contained therein is used to crosslink with an isocyanate or a melamine-based curing agent.

Further, JP-A-61-36374, JP-A-61-296073, JP-A-62-62
As seen in -25104, an isocyanate group having reactivity with a hydroxyl group contained in the fluoropolymer,
A method of reacting a compound having an α, β-olefinic unsaturated group to produce an active energy ray-curable fluoropolymer is also known.

[Problems to be Solved by the Invention] An active energy ray-curable fluoropolymer obtained by reacting a conventional hydroxyl group-containing fluoropolymer with a compound having an isocyanate group and an α, β-unsaturated group is Due to its high viscosity, there is a problem that a relatively large amount of diluent is required when used for applications such as paints. Normally, a system that performs active energy ray curing does not include a solvent removal step by heat for the purpose of shortening the step. Therefore, a reactive diluent (for example, a polyfunctional acrylate) is used as a diluent for the active energy ray-curable coating material. When a large amount of this reactive diluent is used, there has been a problem that the weather resistance and the elongation of the coating film, the adhesion to the substrate, etc. are reduced.

[Means for Solving Problems] The present invention has been made to solve the above problems, and is characterized by including the following (a), (b), (c) and (d): It is an active energy ray-curable composition.

(A) An unsaturated group-containing fluoropolymer obtained by reacting a hydroxyl group-containing fluoropolymer with an α, β-unsaturated carboxylic acid or a derivative thereof.

(B) (Meth) acrylate-based monomer.

(C) Fluoroalkyl group-containing (meth) acrylate-based monomer.

(D) An active energy ray curing initiator.

In the present invention, as the fluoropolymer, a copolymer of a fluoroolefin and another copolymerizable ethylenically unsaturated compound (hereinafter referred to as a copolymerizable monomer) is preferably used. As the fluoroolefin, a fluoroolefin having 2 to 3 carbon atoms such as tetrafluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, and hexafluoropropylene is preferable, and tetrafluoroethylene and chlorotrifluoroethylene are particularly preferably used.
The copolymerization ratio of this fluoroolefin is preferably about 30 to 70 mol%. When the proportion of fluoroolefin is larger than the above range, the solubility in a solvent or a diluent is deteriorated, which is not preferable. On the other hand, when it is small, sufficient weather resistance cannot be obtained, which is not preferable. Copolymer monomers include vinyl ethers, allyl ethers, vinyl esters, and (meth) acrylic monomers (the term "(meth) acrylic monomer" used herein has an acryloyl group or a methacryloyl group). The term "(meth) acrylate" refers to a compound, and the term "(meth) acrylate" refers to an acrylic acid ester or a methacrylic acid ester), olphins, and the like. At least a part of these copolymerizable monomers needs to have a hydroxyl group or a group that can be converted into a hydroxyl group (hereinafter, collectively referred to as a functional group). In particular, it is preferable to use the copolymerizable monomer having the functional group and the copolymerizable monomer having no functional group in combination. The copolymerization ratio of the copolymerizable monomer is 70 per copolymer.
It is preferably about 30 to 30 mol%. When the proportion of the copolymerizable monomer is larger than the above range, the proportion of the fluoroolefin becomes small and sufficient weather resistance cannot be obtained, which is not preferable. Further, when the proportion of the copolymerizable monomer is small, the solubility in a solvent or a diluent becomes small, which is not preferable. The copolymerization ratio of the copolymerizable monomer having the functional group and the copolymerizable monomer having no functional group is about 1 to 45 mol% and 0 to 69 mol% based on the copolymer, respectively. preferable.

Here, examples of the copolymerizable monomer having no functional group include vinyl ethers, allyl ethers, vinyl esters, or (meth) acrylates having a linear, branched or alicyclic alkyl group or a fluoroalkyl group. Examples include roots and olefins. Preferably, at least one kind of vinyl ether having a linear, branched or alicyclic alkyl group having 1 to 10 carbon atoms, particularly 2 to 6 carbon atoms, or at least one kind of this vinyl ether and another functional group is contained. It is a combined use with a non-copolymerizable monomer. Here, as preferable vinyl ethers,
Examples thereof include ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, cyclohexyl vinyl ether, and 2,2,3,3-tetrafluoropropyl vinyl ether.

Further, as the copolymerizable monomer having a functional group, a hydroxyalkyl vinyl ether having a hydroxy group, a hydroxyalkyl vinyl ester, a hydroxyalkyl (meth) acrylate, a carboxyalkyl vinyl ether having a carboxyl group, a carboxyalkyl vinyl ester, a carboxyalkyl ( (Meth) acrylate, etc., epoxy group-containing glycidyl vinyl ether, glycidyl vinyl ester, glycidyl (meth) acrylate, etc. isocyanate group-containing isocyanate alkyl vinyl ether, isocyanate alkyl vinyl ester, isocyanate alkyl (meth) acrylate, etc. Alkyl vinyl ether, aminoalkyl vinyl ester, aminoalkyl (meth) a Such relations are exemplified.
Further, the copolymerizable monomer may be a compound having a high molecular weight side chain as described later. Specifically, for example, there is a hydroxyl group-containing monomer obtained by adding a lactone compound or an alkylene oxide to the above-mentioned monomer having a hydroxyalkyl group. When only a copolymerizable monomer having a functional group other than a hydroxyl group is used as a monomer having a functional group, a hydroxyl group is introduced by an appropriate method (for example, reacting a polyhydric alcohol with a carboxyl group). There is a need.

An unsaturated group-containing fluoropolymer can be obtained by reacting the hydroxyl group-containing fluoropolymer obtained as described above with an α, β-unsaturated carboxylic acid or a derivative thereof. Examples of the α, β-unsaturated carboxylic acid or its derivative include maleic anhydride, acrylic acid, meacrylic acid, acrylic acid anhydride, methacrylic acid anhydride, and acid chlorides thereof. In particular, α,
The use of β-unsaturated carboxylic acid chloride is preferable because it has the advantages that the reaction can be carried out at room temperature and the polymer formed does not gel.

The α, β-unsaturated carboxylic acid chloride used here has the following structure.

[R is hydrogen or an alkyl group] Specific examples thereof include methacrylic acid chloride and acryl acid chloride.

The reaction ratio between the hydroxyl group-containing fluoropolymer and the α, β-unsaturated carboxylic acid chloride is α,
It is necessary that the ratio is 0.01 to 1.0 expressed as the ratio of the number of β-unsaturated carboxylic acid chlorides / the number of hydroxyl groups. When the number of α, β-unsaturated carboxylic acid chlorides is less than this ratio, a fluoropolymer having a sufficient number of unsaturated groups cannot be obtained, and when the number is more than this ratio, unreacted α is unreacted. The .beta.-unsaturated carboxylic acid chloride compound remains, and when the amount thereof increases, there is a possibility that the physical properties of the coating film after curing may be deteriorated. In addition, unreacted α, β
-Distillation action of unsaturated carboxylic acid chloride compound may be required, which is not preferable.

The method for reacting the hydroxyl group-containing fluoropolymer with α, β-unsaturated carboxylic acid chloride is not particularly limited. However, usually, the hydroxyl group-containing fluoropolymer is dissolved in a solvent, to which the α, β-unsaturated carboxylic acid chloride compound is added, and the reaction is performed under stirring at a temperature of about 20 to 30 ° C. for about 10 to 40 minutes. Done by.
In this reaction, it is preferable to add a suitable base for the purpose of capturing HCl generated as a by-product of the reaction. Examples of the base include pyridine, N, N-dimethylaniline, tetramethylurea, triethylamine, magnesium metal and the like. In addition, an inhibitor may be allowed to coexist in the reaction in order to inhibit the polymerization reaction of the unsaturated group, but in the case of this reaction, the necessity thereof is not particularly recognized.

As the specific fluoropolymer in the present invention, a polymer having an intrinsic viscosity of 0.01 to 2.0 dl / g measured at 30 ° C. in terahydrofuran in an uncured state is preferably adopted.

The composition of the present invention contains an active energy ray curing initiator in addition to the above specific fluoropolymer. Examples of the active energy ray curing initiator include photocuring initiators, specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-methyl vesoin, benzophenone, Michler's ketone, benzyl, benzyl dimethyl ketal, benzyl diethyl ketal, anthraquinone, methyl anthraminone, 2,2
-Diethoxyacetophenone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, anthracene, 1,1-dichloroacetophenone, methylorthobenzoylbenzoate and the like.

The compounding amount of the active energy ray curing initiator is about 0.1 to 10 parts by weight, particularly 0.5 to 7 parts by weight, relative to 100 parts by weight of the cured body forming component.
About parts by weight is preferably adopted. If the amount of the active energy ray curing initiator is too small, the curing time becomes long, which is not preferable, and if it is too large, problems such as yellowing of the cured product may occur, which is not preferable.
Further, the cured body-forming component here is a component that gives a cured body by the action of active energy rays, such as an unsaturated group-containing fluoropolymer, a reactive diluent described later, and a fluoroalkyl group-containing (meth) acrylate monomer. When it contains, these are also included in the cured body forming component. However, a substance that does not form a cured product due to the action of active energy rays, such as a solvent, is not included in the cured product forming component.

In addition, the composition of the present invention may contain a solvent or the like to reduce the viscosity depending on its use. As such a solvent, xylene, aromatic hydrocarbons such as toluene,
Esters such as ethyl acetate and butyl acetate, acetone,
Examples thereof include ketones such as methyl ethyl ketone and methyl isobutyl ketone, and glycol ethers such as ethyl cellosolve. The composition of the present invention contains a (meth) acrylate-based monomer and a fluoroalkyl group-containing (meth) acrylate-based monomer that imparts water / oil repellency, a low refractive index and the like. Examples of the (meth) acrylate-based monomer include monofunctional and polyfunctional ones. As the polyfunctional (meth) acrylate monomer, a compound in which a hydroxyl group of a compound such as diol or triol is replaced with a (meth) acrylate group is generally known. Specifically, 1,3-butanediol di (meth) acrylate, 1,4
-Butanediol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, diethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri Examples thereof include (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. Among these, those having a low viscosity are particularly preferable.

The fluoroalkyl group-containing (meth) acrylate-based monomer has a general formula, (In the formula, R ₁ is a hydrogen atom or a methyl group, m is an integer of 1 to 10, n is an integer of 1 to 21, and X is a hydrogen atom or a fluorine atom). Is _{CH 2 = CH-COOCH 2 -} (CF 2) 6 H, can indicate the like. Each of the above can be used alone or in combination of two or more.

The ratio of each component of the composition of the present invention is such that the specific fluoropolymer, the monofunctional or polyfunctional (meth) acrylic monomer, and the fluoroalkyl group-containing (meth) acrylate are 1 to 98/1 to 98/1 to respectively. 98% (parts by weight), especially 20-60
/ 10-40 It is preferable to mix in the ratio of 10-40 (polymerization part).

Further, the composition of the present invention may contain various additives in addition to the compounds described above. Examples of such additives include leveling agents, viscosity modifiers, light stabilizers, moisture absorbers, pigments, dyes and reinforcing agents. The blending amount of these additives is appropriately determined according to the purpose.

The composition of the present invention can be cured by active energy rays (eg, ultraviolet rays, electron rays, γ rays, etc.).

[Example] Synthesis Example 1 [Synthesis of Fluoropolymer Containing Hydroxyl Group] According to the method described in Example 1 of JP-A-57-34107,
From the monomer composition shown in Table 1 below, polymers A-1, A-2, A
-3 and A-4 were produced. The hydroxyl value (OHV) and number average molecular weight ( _Mn ) of the polymer are shown in Table 1.

However, CTFF is chlorotrifluoroethylene, HBVE is hydroxybutyl vinyl ether, CHVE is cyclohexyl vinyl ether, EVE is ethyl vinyl ether, and TFE is tetrafluoroethylene.

Synthesis Example 2 [Synthesis of lactone-modified hydroxyl group-containing fluoropolymer] A mixture of the polymer produced by Synthesis Example 1 and the amounts of ε-caprolactone, dibutyltin dilaurate, and xylene shown in Table 2 was stirred at 145 ° C for 6 hours. After that, the reaction was stopped and cooled to room temperature to obtain a lactone-modified hydroxyl group-containing fluoropolymer B1, B-2, B-3, B-4. The hydroxyl value (OHV) and number average molecular weight ( _Mn ) of each polymer are second
Shown in the table.

Synthesis Example 3 [Synthesis of Fluoropolymer Containing Unsaturated Group] Using the benzene solution of the above polymers A-1 to A-4 and B-1 to B-4 as a base, N, N-dimethylaniline ll [mol%
/ Monomer], dissolved, acrylic acid chloride was added dropwise and reacted at 30 ° C. for 10 to 30 minutes. The reaction was pursued by gas chromatography, and the end of the reaction was confirmed by the disappearance of the residual monomer peak. An unsaturated group-containing fluoropolymer C shown in Table 3 was prepared by changing the amount of acrylic acid chloride used.
-1 to C-10 were synthesized. Table 3 shows the kinds of the above-mentioned hydroxy group-containing fluoropolymer, the number of acrylic acid chloride monomers / the number of hydroxyl groups (monomer / OH), and the intrinsic viscosity at 30 ° C. in tetrahydrofuran.

Examples 1 to 10 By using the C-1 to C-10 unsaturated group-containing fluoropolymers synthesized in Synthesis Example 3, coating compositions having the following compositions were obtained.

(A) Unsaturated group-containing fluoropolymer 50 parts by weight (b) Hexamethylene diacrylate 30 parts by weight (c) Pentaerythritol triacrylate 15 parts by weight 5 parts by weight (e) 5 parts by weight of a photopolymerization initiator (Irgacure 184 manufactured by Ciba-Geigy Co., Ltd.) This coating composition was applied on a glass plate with a film applicator and left at room temperature for 1 minute, followed by a 2kW high pressure mercury lamp It was irradiated with ultraviolet rays at room temperature from a height of 20 cm. The results of the following evaluations of the coating film after ultraviolet irradiation are shown in Table 4.

Touch dryness: Presence or absence of stickiness after 90 seconds of UV irradiation according to JIS K4500.

Judgment ○: None, ×; Yes Weather resistance: Presence or absence of abnormal appearance of the coating film 90 seconds after UV irradiation after exposure to the sunshine weatherometer for 2000 hours.

Judgment ○: None, ×; Yes Chemical resistance: Xylol Raching test of coating film 90 seconds after UV irradiation Judgment ○: 200 times or more passed ×; 200 times or less Comparative Examples 1 to 3 unsaturated group-containing fluoropolymer Table 4 shows the evaluation results of coating films obtained in the same manner as in Examples 1 to 10 except that the commercially available acrylate oligomer shown in Table 4 was used.

Example 11, Comparative Example 4 C-9 unsaturated group-containing fluoropolymer obtained in Synthesis Example 3 or a commercially available acrylic oligomer (biscoat 54
0) 40 parts by weight, 5 parts by weight of a photopolymerization initiator (Irgacure 651) and the amount of hexamethylene diacrylate shown in Table 5, Were mixed to obtain a coating composition. This coating composition was applied on a glass plate with a film applicator, left at room temperature for 1 minute, and then irradiated with ultraviolet rays from a height of 20 cm with a high pressure mercury lamp of 2 kW for 60 seconds at room temperature. Table 5 shows the results of evaluation of the coating film thus obtained, the refractive index, the dryness to the touch, the water / oil repellency and the compatibility of the coating composition. In addition,
The refractive index was measured at 25 ° C using an Abbe type refractometer. The touch dryness was according to JIS K5400. The water / oil repellency was measured by measuring the contact angle of n-hexadecane and water at room temperature. The compatibility was evaluated as × when the coating solution composition was cloudy, and as ○ when it was not cloudy.

[Effects of the Invention] The composition of the present invention is extremely excellent in curability due to active energy rays, and also has a monofunctional or polyfunctional (meth) acrylic monomer and a (meth) acrylic monomer having a fluoroalkyl group. Is well dissolved,
Further, it has effects such as giving a cured product having excellent weather resistance and chemical resistance. Further, the unsaturated group-containing fluoropolymer in the present invention has a relatively low viscosity, so that when it is used as a coating composition, it has excellent coatability and a small amount of diluent can be used. It is particularly excellent in weather resistance, adhesion to a substrate, and elongation.

Since the composition of the present invention having these excellent effects can be cured in an extremely short time, it is possible to reduce the size of the cured product production line, and mass production in a short time. Further, a cured product that is stable for a long time even when exposed to chemicals or outdoors is obtained. Further, since the (meth) acrylate-based monomer having a fluoroalkyl group is well dissolved, a large amount of the fluoroalkyl group-containing (meth) acrylate-based monomer is used even in applications where a low refractive index and water / oil repellency are required. There is an effect that a monomer can be mixed and a good cured product can be obtained at that time.

Claims (2)

(57) [Claims] 1. The following (a), (b), (c) and (d):
An active energy ray-curable composition comprising: (A) An unsaturated group-containing fluoropolymer obtained by reacting a hydroxyl group-containing fluoropolymer with an α, β-unsaturated carboxylic acid or a derivative thereof. (B) (Meth) acrylate-based monomer. (C) Fluoroalkyl group-containing (meth) acrylate-based monomer. (D) An active energy ray curing initiator. 2. The composition according to claim 1, wherein the unsaturated group-containing fluoropolymer is obtained by reacting a hydroxyl group-containing fluoropolymer with an α, β-unsaturated carboxylic acid chloride.