JPS6013861A - Curable coating composition - Google Patents

Abstract

PURPOSE:To provide the titled composition containing a liquid monofunctional (meth)acrylate having cycloalkyl group, a rubber component, etc. at specific ratios, giving a coating film having uniform and easily controllable thickness, and capable of imparting various materials with heat resistance, electrical properties, etc. CONSTITUTION:The objective paint is obtained by compounding (A) 100pts.wt. of a liquid monofunctional (meth)acrylate of formula CH2=C(R)-COOR1(R is H or methyl; R1 is univalent group containing cycloalkyl group) with (B) 2-100pts.wt. of a rubber component, (C) 0-80pts.wt. of a monofunctional (meth)acrylate of formula CH2=C(R)-COOR2(R2 is 8-18C alkyl), (D) 5-150pts.wt. of a polyfunctional (meth)acrylate of formula [CH2=C(R)-COO]n-R3(R3 is n-valent organic group; n>=2) and (E) 0.5-40pts.wt. of a polymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid coating composition curable, in particular by radiation, such as ultraviolet radiation, containing a liquid monofunctional (meth)acrylate having a cycloalkyl group and a rubber component.

Virtually solvent-free curable compositions save resources.

Excellent in terms of energy saving, environmental health and safety,
In addition, when forming a film, it has many advantages over solution-type films, such as easier adjustment of the coating thickness and easier to obtain a film with a uniform thickness. It has been actively researched because it has the advantage of not having a thermal effect on coated objects, and is actually widely used as a surface coating for various materials, adhesives, and various other binders.

By the way, in addition to the above-mentioned advantages, this type of liquid composition is required to have a viscosity that can be easily adjusted to the desired viscosity in order to improve painting workability, while the cured product must have a desired elastic modulus. It is also required to have good elongation properties and satisfy film properties such as heat resistance and electrical properties.

However, conventional compositions of this type generally have the disadvantage that it is difficult to balance the above-mentioned viscosity characteristics with the properties of the cured product, and when it comes to the properties of the cured product, especially those that are photocurable, they generally have excellent flexibility. It has the disadvantage that it is inferior in general properties such as heat resistance and electrical properties, and conversely, those that are excellent in heat resistance and electrical properties are inferior in flexibility, making it difficult to satisfy both properties.

Therefore, it is easy to achieve a balance between these properties, that is, it is easy to adjust the desired viscosity to improve painting workability, and the cured product has the desired elastic modulus and good elongation properties. Liquid (contains no solvent) that satisfies all the basic properties such as heat resistance and electrical properties.
If a curable composition, especially a photocurable composition, can be found, further applications can be expected in various fields.

As a result of intensive studies from this perspective, the inventor discovered that (meth)acrylate with a specific structure dissolves rubber components to a high degree, and that a desired viscosity can be easily obtained by adjusting the amount of this rubber component. At the same time, the composition obtained by adding a polyfunctional (meth)acrylate and a polymerization initiator to the solution of the rubber component and, if necessary, an ordinary monofunctional (meth)acrylate, has curability, particularly photocurability, and After learning that the cured product exhibits a wide range of properties including improved flexibility due to the rubber component, the present invention was completed.

That is, this invention provides a) general formula; CH2=(J)-
10.0 parts by weight of liquid monofunctional (meth)acrylate represented by COOR, (R is hydrogen or a methyl group, RI is a monovalent group having a cycloalkyl group), b) Comb component 2
~100 parts by weight, C) General formula; CH2=C(RI-0
0 to 80 parts by weight of monofunctional (meth)acrylate represented by 00R2 (R is hydrogen or methyl group, R21-i: chain or branched alkyl group having 8 to 18 carbon atoms), d) General formula; [CH2 =C(R)-COO 5 to 150 parts by weight of polyfunctional (meth)acrylate represented by R3 (R is hydrogen or methyl group, R3r/'in valence organic group, n≧2) and e) polymerization initiator The present invention relates to a curable coating composition characterized in that it contains 0.5 to 40 M parts.

The above composition of the present invention uses a specific monofunctional (meth)acrylate as component a, which has the property of arbitrarily dissolving the rubber component as component b. The viscosity can be arbitrarily adjusted by adjusting the amount of the coating agent, and thereby good coating workability can be obtained depending on the purpose of use. Further, this composition can not only be easily cured by heat by using a thermal polymerization initiator as component e, but also can be more easily cured by radiation such as ultraviolet rays by using a photopolymerization initiator.

Moreover, it is possible to obtain the desired elastic modulus through the second curing process and to obtain good elongation properties through the use of rubber components.In particular, by appropriately selecting the type and blending amount of each component, it is easy to balance the two properties. However, as a result, it is possible to obtain a cured product that satisfies not only general properties such as heat resistance and electrical properties but also flexibility. Furthermore, this cured product has excellent water resistance and exhibits extremely suitable performance as a coating material.

In this invention, the liquid monofunctional (meth)acrylate having a cycloalkyl group used as component a is practically cyclohexyl (meth)acrylate, inbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, or these. Substituents on a cycloalkyl group, and (meth)acrylates and rylates in which these cycloalkyl groups are connected via a methylene or oxyethylene chain are included, and these may be used alone or in combination.

These (meth)acrylates having a cycloalkyl group highly dissolve various natural or synthetic rubbers or depolymerized products thereof as component b. Examples of this rubber component include natural rubber, imprene rubber, styrene-butadiene rubber (random or block), styrene-imprene rubber, butadiene rubber, chloroprene rubber, phthyl rubber, polyimbutylene, nitrile rubber, and ethylene-propylene rubber. However, for example, butadiene-based liquid rubber can also be used.The amount of these used should be appropriately selected to obtain the required viscosity. The amount is in the range of 2 to 100 parts by weight.If it is less than 2 parts by weight, the effect of modifying properties or improving flexibility will be insufficient unless a rubber component of a fairly high molecular weight type is used. On the other hand, if the amount exceeds 100 parts by weight, it is necessary to use a low-molecular rubber, and in this case, the effect of the rubber component on flexibility becomes smaller.

The composition of the present invention is prepared by dissolving the above-mentioned rubber component in a monofunctional (meth)acrylate as the above-mentioned C component, and further adding chain-like or branched alkyl monofunctional (meth)acrylate as the C component depending on the purpose. The acrylate can be blended in a proportion of 0 to 80 parts by weight per 1 part of 100 ml of the liquid monofunctional (meth)acrylate. This monofunctional (meth)acrylate preferably has a chain or branched alkino Q group with a carbon number in the range of 8 to 18, specific examples of which include 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate. , lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, etc. alone or in mixtures.

These C components are compatible with the solution consisting of the above components a and b, and do not need to be used if you want to obtain a hard cured product, but are necessary if you want to obtain a relatively soft product. However, if the amount exceeds 80 parts by weight, the improvement effect will hardly be recognized.

Component C used as an essential component in this invention is for maintaining the curing speed or imparting desired hardness to the cured product, and is a polyfunctional (meth)acrylic group having two or more (meth)acryloyl groups in the molecule. Various monomers or oligomers known as acrylates are used. Specifically, ethylene glycol di(meth)acrylate, 1,3-propanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,3-pentanediol di(meth)acrylate,
1,6-hexanethiol di(meth)acrylate, decamethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate (meth)acrylate, tripropylene glycol di(meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate,
1,4-Cyclohegysandiol di(meth)acrylate, 1,4-benzenediol di(meth)acrylate, 1,2,4-butanetriol tri(meth)acrylate, glycerol tri(meth)acrylate, trimethylolpropane tri( Examples include meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and other similar derivatives or oligomeric polyfunctional (meth)acrylates, which may be used alone or in combination. The amount of these used is the liquid monofunctional (
The proportion is 5 to 150 parts by weight per 100 parts by weight of meth)acrylate. If it is less than 51 parts by weight, the effect on maintaining the curing rate will be small, and if it exceeds 150 parts by weight, the cured product will become hard and loose or lose compatibility, so both are inappropriate.

By using a photopolymerization initiator as a polymerization initiator as component C, the composition of the present invention can be easily and quickly cured with radiation such as ultraviolet rays. As the above-mentioned photopolymerization initiator, various kinds of initiators and sensitizers that are generally used for ultraviolet curable coatings can be used. For example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, 2-methylbenzoin, benzophenone, Michler's ketone, benzyl, benzyl dimethyl ketal, benzyl diethyl ketal, anthraquinone, methylanthraquinone, diacetyl, acetophenone, diphenyl disulfide, anthracene. and the like, and those in which these are used in combination with small amounts of sensitizing aids such as amines.

Furthermore, the composition of the present invention can also be thermally cured by using a thermal polymerization initiator instead of or together with the photopolymerization initiator described in 2. Examples of the thermal polymerization initiator include peresters such as tertiary butyl peroctoate and tertiary butyl perpivalate, bis-(4-
Percarbonate esters such as tert-butylcyclohexyl)-peroxydicarbonate, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as di-tert-butyl peroxide and dicumyl peroxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, Examples include peroxide-based polymerization initiators such as hydroperoxides such as cumene hydroperoxide and combinations thereof with metal promoters such as cobalt-n salts of 2-ethylhexanoic acid and naphthenic acid, and other azo compounds. can also be used.

The amount of these photopolymerization initiators and thermal polymerization initiators used is as described in C.
It should be in the range of 05 to 40 parts by weight based on 100 parts by weight of liquid monofunctional (meth)acrylate component. 0.5
If it is less than 40 parts by weight, sufficient polymerization initiation cannot be carried out, whereas if it is used in excess of 40 parts by weight, no particular effect is observed and it lacks practicality, so both are inappropriate.

Polymerizable unsaturated compounds such as (meth)acrylates and other allyl compounds and vinyl compounds other than those mentioned above may be added to the composition of the present invention within the range permitted in terms of curing conditions and compatibility. . In addition, known thermal polymerization inhibitors are used to improve the thermal stability of the composition, known plasticizers are used to improve the flexibility of the cured product, and soluble agents are used to appropriately adjust the properties during coating. It is possible to add polymeric materials, known anti-aging agents to improve high temperature deterioration after curing, and improvers to improve adhesion to materials.

As detailed above, the curable coating composition of the present invention can be adjusted to any desired viscosity by adjusting the amount of the rubber component as component b, so that it can be coated well using an appropriate coating method. On the other hand, it can be easily cured by radiation such as ultraviolet rays or heat after coating, and the cured product can satisfy various properties such as heat resistance, electrical properties, flexibility, and water resistance. It has the characteristic of being able to

Examples of the present invention will be shown below in comparison with comparative examples.

Examples 1 to 6 and Comparative Example 1 In Examples 1 and 2, B was added to cyclohexyl acrylate (trade name Viscoat 155, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as component C at the blending ratio (parts by weight) shown in Table 1. After compounding and dissolving imprene rubber (synthetic isoprene rubber IR-10 manufactured by Clarei Soprene Chemical Co., Ltd.) as a component into small pieces, lauryl tridecyl acrylate (trade name manufactured by Osaka Organic Chemical Industry Co., Ltd.) as a component C was added. LTA
) and 1,6-hexanediol diacrylate as component C in the proportions (parts by weight) shown in Table 1, making the total blended amount 100 parts by weight, and to this was added benzyl dimethyl ketal (manufactured by Ciba Geigy) as component C. A photocurable coating composition of the present invention was prepared by adding 4 parts by weight of Irgacure 651 (trade name).

In Examples 3 to 6, cyclohexyl acrylate as component C and styrene-butadiene-styrene block copolymer (trade name: CARIFLEX TR-KX 65, manufactured by Shell Chemical Co., Ltd.) as component B were mixed in the proportions shown in Table 1 ( parts by weight)
After dissolving, lauryl tridecyl acrylate as component C and 1,6-hexanediol diacrylate as component C were added at the mixing ratio (parts by weight) listed in Table 1 in the same manner as in Example 1.2. Further, 4 parts by weight of benzyl dimethyl ketal as component C was added to the total blended amount of 100 parts by weight to obtain the photocurable coating composition of the present invention.

In Comparative Example 1, a comparative photocurable coating composition was prepared with the same formulation as in Examples 1 to 6, except that the rubber component as component b was not used.

The results of examining the viscosity and cured product properties of the compositions of these Examples and Comparative Examples are shown in Table 1 below.

Table 1 The physical properties of the cured product were determined as follows. That is, each composition was cast onto a glass plate to a thickness of about 0.3 fnm, a solution sample was prepared by closely covering it with a polyester film, and the solution sample was heated to a thickness of about 4.0 fnm under degassing using an ultraviolet exposure device equipped with a high-pressure mercury lamp. A cured sheet was prepared by exposing to light at mJ/cn1, and a test piece for a tensile test was punched out from this sheet, and a tensile test was conducted at a tensile speed of 50 mm/min.

As is clear from the results in "-", Comparative Example 1 consists of cyclohexyl acrylate, lauryl tridecyl acrylate, and 1,6-hexanediol diacrylate and does not contain a rubber component, so its viscosity is a simple mixture of acrylic monomers and is very low. Therefore, for example, it may be possible to apply it in a very thin layer, but in general applications, a desired viscosity is required, making it difficult to put such a composition into practical use in many fields.

On the other hand, in the composition of Example 1.2 in which impregnated rubber was used in combination, the viscosity was variable to [1] due to the rubber component, and the elastic modulus of the cured product was also the same as that of Comparative Example 1. It is almost the same, but the elongation is improved,
A cured product has been obtained that has good heat resistance, electrical properties, etc. and improved so-called toughness.

Furthermore, in Examples 3 to 6, a styrene-butadiene-styrene block copolymer was blended as a rubber component, and as in Examples 1 and 2, by increasing the amount of the rubber component,
11 Its viscosity properties can be widely controlled. At this time, as the amount of the rubber component increases, the elastic modulus decreases if the monomer types are the same (Example 4.5), but this is due to lauryl tridecyl acrylate and d
1,6-hexanethiol diacrylate 1 as a component
A desired value can be obtained by changing the blending ratio of (Example 6).

Thus, according to the compositions of Examples 1 to 6, desired viscosity characteristics and desired cured product characteristics can be easily obtained,
It can be seen that it has extremely high utility value as a coating composition.

Examples 7 to 10 and Comparative Example 2 Styrene-butadiene-styrene as component b was added to inbornyl acrylate (monomer QM-589 manufactured by Rohm and Half Co., Ltd.) as component a in the proportions (parts by weight) shown in Table 2. Block copolymer (same as in Examples 3-6)
After blending and dissolving, Table 2 shows the combination ratio of Nazuzu (
Add lau 4-nor tridecyl acrylate as component C and pentaerythritol triacrylate as component d to 00 parts by weight, add 4 parts by weight of benzyl dimethyl ketal as component C, and add 4 parts by weight of benzyl dimethyl ketal as component C. In addition, a photocurable coating composition of Komei was prepared.

In addition, Comparative Example 2 was a comparative photocurable coating composition having the same formulation as in "Examples 7 to 0" except that the rubber component as component b was not used. .

The results of examining the viscosity and cured product properties of the compositions of these Examples and Comparative Examples are as shown in Table 2 below.

Table 2 As is clear from Table 2 above, the compositions of Examples 7 to 10 can also modify the viscosity properties over a wide range as in Table 1, while achieving both these viscosity properties and the properties of the cured product. It can be seen that it is easy to achieve this.

In addition, although Examples 1 to 10 above are all about photocurable products, the thermal polymerization of this invention was performed using benzoyl peroxide as a thermal polymerization initiator instead of the photopolymerization initiator in each of the above-mentioned formulations. When a cured ml coating composition was used, the same results as above were obtained in this case as well.

Patent applicant: Nitto Electric Industry Co., Ltd.

Claims (2)

[Claims] (1)ω~ General formula; CH2=C(R)-COORI (
R is hydrogen or a methyl group;
00 parts by weight, C) General formula; CH2=C(R)-COO
R2 (R is hydrogen or methyl group, R2 has 8 to 18 carbon atoms)
monofunctional (chain or branched alkyl group)
meth)acrylate 0 to 80 parts by weight, d) General formula; [
5 to 150 parts by weight of polyfunctional (meth)acrylate represented by CH2=C(R)-COO circle R3 (R is hydrogen or methyl group, R3 is n-valent organic group, n≧2) and e) polymerization initiator A curable coating composition comprising 0.05 to 40 parts by weight. (2) The curable coating composition according to claim f1), wherein the polymerization initiator of component e is a photopolymerization initiator and is radiation curable.