JPS59113075A - Photo-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:To prepare the titled composition having rapid curability and high adhesivity, and giving tough and flexible cured product, by using a urethane prepolymer composed of an organic polyisocyanate, an ethylenic unsaturated compound having active hydrogen, and a specific compound, in combination with a photo-polymerization initiator. CONSTITUTION:The objective composition contains (A) a urethane prepolymer having two or more terminal groups having polymerizable ethylenic double bond, and containing (i) an organic polyisocyanate (e.g. tolylene diisocyanate), (ii) an ethylenic unsaturated compound having active hydrogen (e.g. ethylene glycol monoacrylate), (iii) the compound of formula (R<1>-R<3> are 2-4C alkylene; l, m and n are >=1; l+m+n is 3-12) [e.g. tris(2-hydroxyalkyl)isocyanurate], and if necessary (iv) a polyol, and (B) a photo-polymerization initiator. The component is preferably reacted in a manner to attain the equivalent ratio of (the active hydrogen group of the components ii, iii and iv) to (the NCO group of the component i) of 0.9-1.4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive adhesive composition, and particularly to an excellent photosensitive adhesive composition that has fast curing properties and high adhesive properties, and also has both toughness and flexibility.

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.
Generally, it does not contain volatile organic solvents, which is very desirable from the point of view of environmental conservation, 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. It has begun to be put to practical use in a wide range of fields, including paints, printing inks, adhesives, overlays and other coating materials for flexible circuits, solder resists for printed circuit boards, etching resists, and inks for printed circuits.

Adhesives are required to have various performances depending on the type of adherend and application, and in particular, in the assembly of precision parts, etc., it is required to prevent deformation and distortion due to thermosetting. Therefore, there has been a demand for the development of an adhesive that can be quickly bonded to non-absorbent adherends that do not like heat curing and has excellent adhesive strength.

Photocurable resins are attracting attention as new adhesives that meet these demands, but conventional photosensitive adhesives using photocurable resins as a pace vehicle do not simultaneously cure quickly and have high adhesive strength. It wasn't satisfying. For example, a photosensitive adhesive whose main component is an adduct of epoxy resin and β-unsaturated acid is rapidly cured by ultraviolet irradiation, but has the drawback of low adhesive strength. Furthermore, although photosensitive adhesives mainly composed of liquid polybutadiene or liquid polyisoprene and acrylic ester have excellent adhesive strength when irradiated with ultraviolet rays, they require a relatively long time for complete curing. 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 adhesive composition that simultaneously has fast curing properties and high adhesive properties, and is also tough and flexible.

The present invention provides a photosensitive adhesive 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 (3). , ethylenically unsaturated metal compound (B) having active hydrogen, general formula ゛(R0)6H (R1, R2 and R3 are each an alkylene group having 2 to 4 carbon atoms. 1. Hydrogen contained in the alkylene group At least one of them may be substituted with halogen, l,
m and n are each integers of 1 or more, and the total is 3 to
It is 12. The present invention relates to a photosensitive adhesive composition comprising a prepolymer formed from a compound (C) represented by (C) and optionally an optional polyol Q)).

Various types of organic polyisocyanate can be used in the present invention, such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TD), and tolidine diisocyanate (TODI).
, xylylene diisocyanate (XDI), naphthylene diisocyanate (NDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (
HDI), dicyclohexylmethane diisocyanate (
Examples include diisocyanates such as HMDI), polyisocyanates such as triphenylmethane triisocyanate, and polymethylene polyphenylisocyanate (PAPI).

In the present invention, various compounds can be used as the ethylenically unsaturated compound B) having active hydrogen, but representative examples include ethylene glycol, propylene gellicol, 1,3-propanediol, and 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; 4 such as meth)acrylate, pentaerythritol, etc.
Examples include di- and tri(meth)acrylates of alcohols with higher valences.

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.

Further, the derivatives thereof are obtained by reacting alkylene oxides such as ethylene oxide and propylene oxide, and the alkylene oxides may be reacted all at once, or one or more kinds may be reacted stepwise. In general formula (1), β, m
The sum of n 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 sinterability and elongation of the resin are further improved.

In the present invention, polyol [)) can be used if necessary. As polyol 10+, various polyester polyonyls, polyether polyols, and other polyols can be used. Examples of polyester polyols include adi, pinic acid, superric acid, sebacic acid,
The acid component is an aliphatic dicarboxylic acid having 4 to 20 carbon atoms such as brassylic acid, terephthalic acid, isophthalic acid, etc., and an acid component having 1 to 20 carbon atoms such as ethylene glycol, propylene glycol, neopentyl glycol, hexamethylene glycol, etc.
Use polyester polyols or polycaprolactone polyols whose polyol components include aliphatic diols of No. 6, ether glycols such as diethylene glycol and dipropylene glycol, spiroglycols, and N-alkyl dialkanolamines such as N-methyljetanolamine. Specific examples include adipate polyols such as polyethylene adipate polyol, polybutylene adipate polyol, and polyethylene propylene adipate polyol, and terephthalic acid polyols (e.g., Toyobo Co., Ltd., trade name: Vylon RU
%PiC1:/RV-200L), polycaprolactone polyol (eg, Daicel Chemical, trade name Plaxel 212, Plaxel 22o), and the like. - Specific examples of polyether polyols include polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene polyol, and the like.

Other polyols include polycarbonate polyols (e.g., Bayer AG, West Germany, trade name Desmofene 2020E), polybutadiene polyols (e.g., Nippon Soda, trade names G-1000, G-2000, G-300).
,0, Idemitsu Petrochemical, trade name Poly bd R-45
HT), polypentadiene polyol, castor oil polyol, and the like.

The prepolymer in the present invention can be synthesized by various known methods. - Typical synthesis examples are one-step reaction method or
This is a stepwise reaction method in which two components are first reacted, and then a third component is reacted.

That is, for example, by reacting compound (1) with (13+'), the terminal NC
A method of synthesizing a prepolymer of O, and then reacting all of compound C) and, if necessary, compound (D), compound cost and [)
) A method of synthesizing a prepolymer of terminal NCO, then adding compound fB)k and reacting, and further adding and reacting compound CI, to compound (B), and from compound (3) and (1)) Examples include a method in which a terminal NCO prepolymer is completely synthesized and a mixture of these two types of prepolymers is reacted with the compound (C).

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 adhesive composition, but usually the ethylenically unsaturated compound (B) having active hydrogen, the general formula ( Compound (C) of 1) and the polyol (the chemical equivalent ratio of the active hydrogen group contained in D+ to the NCO group of compound (5) is 09 to 4), preferably 0.
95 ~], 2, and the reaction is usually carried out at 30 to 130°C, preferably 40 to 120'C.
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. Examples include esters such as ethyl acetate and methyl propionate, ethers such as dioxane and cellosolve acetate, and dimethylformamide and dimethyl sulfoxide.

In the photosensitive adhesive 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 fast curing property due to the compound (C) represented by the general formula (1) used in the present invention,
The above compound C has properties such as excellent adhesiveness.
The number average molecular weight of the total prepolymer per mole is 800
-15,000, particularly preferably in the range of 900-12,000, and within this range the above-mentioned properties can be sufficiently exhibited while preventing the possibility of gelation during synthesis. The proportion of the prepolymer containing the compound (C) can be appropriately determined depending on the intended performance of the adhesive, but a preferred proportion of the entire prepolymer is on a 30-weight plate.

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 ethylenically unsaturated compounds, but typical examples include styrene, vinyltoluene, chlorostyrene, l-butylstyrene, α-methylstyrene, divinylbenzene, acrylic acid, methacrylic acid, and queacrylic acid. or methyl, ethyl, isopropyl, n-butyl, l methacrylate
-butyl, two-ethylhexyl, n-nonyl, n-tecyl, lauryl, stearyl ester, etc., n-butoxyethyl acrylic acid or methacrylic acid, cyclohexyl, phenoxyethyl, tetrahydrofurfuryl, glycidyl, allyl, benzyl, tribromophenyl, 2,
3-dichloropropyl, 3-chloro-2-hydroxypropyl, N,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, polyethylene glycol mono(meth)acrylate with a molecular weight (hereinafter referred to as MW) of 200 to 1000, MW 200 to 100o
Polyethylene glycol monomethyl ether mono(meth)acrylate of MW200-1000, polypropylene glycol mono(meth)acrylate of MW2oo
~1000 polypropylene glycol monomethyl ether mono(meth)acrylate, MW2oo~1000
Polyethylene glycol monoethyl ether mono(meth)acrylate of MW 200 to 1000, 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-hexanethiol di(meth)acrylate, polyprolene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, glycerin di(meth)acrylate, ) acrylate, glycerin tri(meth)acrylate, trimethylolethane di(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, acrylamide, N
, N-dimethylacrylamide, N,N-diethylacrylamide, ethylene vinylacrylamide, diallyl phthalate, triallyl isocyanurate, dibutyl fumarate, vinyl acetate, and the like.

However, if present during the urethanization reaction, the ethylenically unsaturated compounds having active water ice should be excluded from the above.

In the present invention, the ratio of the prepolymer to the ethylenically unsaturated compound is 30 to 95 by weight.
:5 is preferable, 50:50 to 80:20
I really like it.

In the present invention, various known compounds can be used as the photopolymerization initiator, such as ketone compounds such as benzophenone, p-methylbenzophemene, p-chlorobenzophenone, Michler's ketone, and acetophenone, benzoin, benzoin methyl ether, and benzoin ethyl Ether, benzoins such as benzoin butyl ether, α-allyl benzoin, αr chlorobenzoin, quinones such as anthraquinone, 2T methylanthraquinone, 1-chloroanthraquinone, p-benzoquinone, 1,4-naphthoquinone, phenyl disulfide, tetramethylthiuram mono Sulfides such as sulfide, sulfonyl chlorides such as β-naphthalenesulfonyl chloride, p-T-chlorobenzenesulfonyl chloride,
Nitro compounds such as 2-bifluorene and 5-nitroacenaphthene, halogenated hydrocarbons such as tetrabromomethane, thioxanthone such as 2-chlorothioxanthone, azo compounds such as azobisisobutyronitrile, etc. Can be mentioned. These photopolymerization initiators can be used in an amount of 0.001 to 10 weight percent, preferably 0.01 to 5 weight percent, based on the total amount of prepolymer and crosslinking agent.

A known thermal polymerization inhibitor may be added for the purpose of stably storing the photosensitive adhesive composition of the present invention.

For example, hydroquinone, mono-tert-butylhydroquinone, 2,5-di/ert-butylhydroquinone, hydroquinone monomethyl ether, catechol, p-tert-butylcatechol, benzoquinone,
, 5-di-tert-butylbenzoquinone, 2,5-diphenyl-p-benzoquinone, 2,6-di-tert-
Examples include butyl-p-cresol and picric acid. It is desirable that these thermal polymerization inhibitors completely prevent only the thermal polymerization reaction (dark reaction) without inhibiting the photocuring reaction, and therefore, the amount added is 0.000% relative to the total amount of the prepolymer and crosslinking agent. 001-25 weight, good weight or 0
．． It is desirable that the weight is in the range of 0.005 to 1.00% by weight.

The photosensitive adhesive composition of the present invention can be cured by a known method, and it is suitable to use, for example, an active light source with a wavelength of 200 to 700 nm. 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.

In addition, in the present invention, other curing means may be used, such as heat curing, that is, curing by radiation mainly consisting of thermal energy such as infrared rays, high frequency waves, or microwaves, or curing by electron beam or gamma radiation.
Curing with ionizing radiation such as a wire can also be employed. 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 1-tert-butyl peroxide, and
Dialkyl peroxides such as -butyl peroxide and dicumyl peroxide, peroxy esters such as ter/-butyl peroxylaurate and terl-butyl peroxybenzoate, and azo compounds such as azobisisobutyronitrile. Can be mentioned.

Cobalt for the above ketone peroxides,
Polymerization accelerators such as metal soaps such as manganese or reducing amines for the above-mentioned hydroperoxides may also be used. Furthermore, although it may be used alone or in combination with the irradiation of the active light source, the electron beam or
When using high-energy ionizing radiation that has the effect of emitting secondary electrons when absorbed by a substance such as a wire, it is not necessary to add an initiator, but a photopolymerization initiator such as the one described above or It may also contain a thermal polymerization initiator.

Furthermore, the composition of the present invention may contain colorants and other additives commonly used in photosensitive compositions of this type.

By introducing an isocyanurate ring into the molecule, the photosensitive adhesive composition of the present invention not only has fast curing properties and high adhesive properties, but also has excellent toughness and flexibility, and improved heat resistance. Provides an adhesive coating. Furthermore, the adhesive composition of the present invention can also be used as a sealant or the like.

A detailed explanation will be given below with reference to synthesis examples and examples.

Synthesis Example 1 524.4y of 2.4-TI)I in a reactor equipped with a stirring device
The mixture was heated to 80°C, and a mixture of 1506.9gI of polyethylene adipate with a molecular weight of 1000 and 1.94y of dibutyltin dilaurate was gradually added, heated to 90°C and reacted for 3 hours, and then cooled at 70°C. death,
2-Hydroxyethyl acrylate (:[-tylene glycol monoacrylate, hereinafter abbreviated as HEA) 1
74.8gl, dibutyltin dilaurate 0.23
A mixture of Y and 0.449% of hydroquinone was gradually added dropwise, and the mixture was reacted for 2 hours and 30 minutes while maintaining the same temperature. Here, tris (2-hydroxyethyl) isocyanurate 0
3PO (propylene oxide 3 mole adduct, hereinafter the same description) 218.4M't After heating to 50°C, the mixture was gradually added dropwise to obtain urethane prepolymer (1).

Synthesis Example 2 In Synthesis Example 1, polybutylene adipate (molecular weight 1000) was used instead of polyethylene adipate, and HEA
2-hydroxypropyl acrylate (hereinafter H
Urethane prepolymer (2) was obtained in the same manner as in Synthesis Example 1 except that urethane prepolymer (abbreviated as PA) was used.

Synthesis Example 3 In Synthesis Example 1, polytetramethylene glycol (molecular weight 1000) was used instead of polyethylene adipate,
Tris(2-hydroxyethyl)isocyanurate 3
Urethane prepolymer (3) was obtained in the same manner as in Synthesis Example 1, except that tris(2-hydroxyethyl)isocyanurate.aEO was used instead of PO.

Synthesis Example 4 203.4y- of 2.4-TDI in a reactor equipped with a stirring device
Pour at 70°C with heating port, HPA 1520y, dibutyltin dilaurate 0.42y and hydroquinone 0.3
After gradually dropping a mixture of 8y and reacting for 3 hours, tris(2-hydroxyethyl)isocyanurate 3P0
1.69.5 yk was added and reacted for 2 hours to obtain urethane prepolymer (4).

Synthesis Example 5 Urethane prepolymer (5) was prepared in the same manner as in Synthesis Example 1 except that trimethylolpropane was used instead of tris(2-hydroxyethyl)isocyanurate/3POO.
I got it.

Synthesis Example 6 Urethane prepolymer (6) was prepared in the same manner as in Synthesis Example 3 except that trimethylolpropane was used instead of tris(2-hydroxyethyl)isocyanurate 3EOO.
I got it.

Examples 1 to 5 and Comparative Examples 1 to 3 Using the prepolymers obtained in each synthesis example, each component was mixed in the proportions shown in Table 1 and thoroughly stirred to prepare a photosensitive composition. Using each of the photosensitive compositions thus obtained, the curing time and adhesive strength were measured by the following methods, and the results are also shown in Table 1.

<Measurement of curing time> A test in which a photosensitive composition was applied onto a clean polyester film with a thickness of 0.12 mm, a similar polyester film was layered on top of it, and a liquid layer with a thickness of 50 μm was formed using a spacer. Got a piece. This test piece was irradiated with ultraviolet rays from a distance of 15 (:!7+1) using an IKW high-pressure mercury lamp, and the curing time was measured.

<Measurement of adhesive strength> A photosensitive composition is applied onto a clean glass plate with a thickness of 5 mm that has been thoroughly washed and completely dried, and a similar glass plate is placed on top of it using a spacer to increase the adhesive layer thickness. After confirming that the adhesive layer was uniform, a test piece was obtained by irradiating ultraviolet rays in the same manner as in measuring the curing time. The tensile shear strength of the obtained test piece was measured using an automatic tensile testing machine at a tensile rate of 50 am/min, and the average value of the five test pieces was taken as the measured value. In addition, as a non-irradiation side adherend, a steel plate (5m + x thickness) was used instead of glass.
A similar test was conducted using a methacrylic plate (3 mm thick), and the results are shown in Table 1.

As can be seen from the results in Table 1, the adhesive of the present invention has excellent curability and 1. It has excellent adhesion to optically transparent materials such as glass and transparent plastics, as well as solid metals, plastics, water phases, etc., and is useful in a wide range of fields.

Claims (4)

[Claims] (1) Terminal fund 2 with polymerizable ethylenic double bond
In the photosensitive adhesive composition containing an unsaturated urethane prepolymer having at least 10% of the total number of unsaturated urethane prepolymers and a photopolymerization initiator, the prepolymer is an organic polyisocyanate (1), an ethylenically unsaturated compound having active hydrogen [F]), and a general formula of %. %) (R1, R2 and R3 are each an alkylene group having 2 to 4 carbon atoms, at least one of the hydrogens contained in the alkylene group may be substituted with a halogen, and β5m and n are each an alkylene group having 1 or more carbon atoms. An integer whose sum is 3 to 12
It is. 1. A photosensitive adhesive composition comprising a prepolymer formed from a compound C) represented by the following formula and optionally a polyol D). (2) M of total prepolymer per 1 mole of compound (C)
The composition according to claim 1, wherein n is in the range of 800 to 15,000. (3) The composition according to claim 1, wherein the proportion of the prepolymer containing compound (C) k in all the prepolymers is 30% by weight or more. (4) The composition according to any one of claims 1 to 3, wherein l, m, and n are each integers of 2 to 3.