JPH0247119A - Photo-curable composition - Google Patents

Abstract

PURPOSE:To get rid of reaction inhibition caused by oxygen, to decrease skin irritation and to improve curing speed by compounding a specified vinyl ether with a specified polythiol compd. CONSTITUTION:A vinyl ether compd. (A) of formula I [wherein m and n are each 0 or larger and m+n is at least 2; R is a structure of (i)-(iii), wherein (i) is a structure of formula II-V or a structure wherein part of H atoms on the arom. rings of formula II-V are substd. with halogen atoms or 4C or lower alkyls (wherein R' is -SO2-, -CO-, -S-, -CR<1>R<2>-; R<1-2> are each H, CH3, C2H5 or phenyl); (ii) is formula VI (wherein p is at least 1; R<3> is H, a halogen or 4C or lower alkyl; (iii) is formula VII (wherein q is at least 2)] is compounded with a polythiol compd. (B) of formula VIII (wherein R<4> is a polyvalent org. group; r is at least 2) having an equivalent ratio of the thiol group of the component B of 0.3-1.8, pref. 0.8-1.2 based on the vinyl ether group of the component A.

Description

Detailed Description of the Invention "Industrial Application Field" The composition of the present invention is a raw material composition that reacts and cures with ultraviolet rays to become a resinous or elastomer-like polymer, and this curing method is applicable to paints, coating materials. It is used in fields such as ink, molded products, adhesives, and image formation.

``Prior art'' So-called photocurable photosensitive resins can be classified into radical type and cation type depending on the ionicity of the reactive species, but cation type has been developed recently, and radical type is the mainstream. there were.

Among the radical types, the so-called acrylic type, in which an acrylic acid derivative is used as a photosensitive group and is polymerized and cured by photoradical polymerization, is still widely used. Since this material uses radical chain polymerization as its curing mechanism, it is susceptible to the inhibiting effect of oxygen in the air, and moreover, it is common to use a relatively low molecular weight compound that is a reactive diluent with the prepolymer. The unavoidable problems are skin irritation and toxicity of the drug.

On the other hand, even if it is a radical type, there are known photosensitive resins whose curing mechanism is not chain polymerization but polymer formation through an addition reaction using a photosensitizer as a radical generation catalyst. An example of this is the so-called ene-thiol type, which utilizes a photo-Michael addition reaction between a thiol group and a carbon-carbon double bond.

Prior art of this type is disclosed in U.S. Pat. No. 3,661,744 and U.S. Pat. No. 3,697,402. A detailed examination of these contents reveals that compounds with allyl groups (-CH, -CH=CH,) are disclosed as polyene compounds, and if these are used, the above-mentioned reaction inhibition by oxygen and skin irritation can be avoided. However, since the curing speed is slower than that of the acrylic type, a very important and unavoidable problem arises, especially the reduction in productivity. Ta.

Incidentally, the claims of the above-mentioned US Pat. No. 3,697,402 mention vinyl ether, but as far as the specification is concerned, only divinyl ether of diols, especially diethylene glycol, is specifically mentioned as vinyl ether. Regarding vinyl ethers with an aromatic ring, only one example (vinyl phenyl ether) is listed, and there are no concerns regarding the reactivity, such as photocuring properties, when using vinyl ethers with an aromatic ring. There is no description that suggests anything.

``Problem to be solved by the invention'' Based on the above technical knowledge, the curing speed is equivalent to that of the acrylic type, and therefore there is no need to consider restrictions on the film thickness after curing, and it may be possible to If a composition for a photocurable resin can be obtained that has no deterioration in productivity, is not inhibited by oxygen, and has low skin irritation, the above-mentioned problems will be solved at once.

"Means for Solving the Problems" Results 1. The present inventors found that there was no reaction inhibition by oxygen,
After intensive study on compositions with low skin irritation and high curing speed, we found that certain aromatic rings and certain vinyls, the usefulness of which is not specifically disclosed in the above-mentioned US patent, were used as polyene components. If ether compounds and mercaptans with a structure are used, a photocurable composition can be obtained that can be cured simply by irradiation with ultraviolet light, regardless of whether or not a photosensitizer is added.If a sensitizer is further added, the above-mentioned The present invention has been achieved by discovering that the composition can be cured at a much faster rate than the prior art using allyl compounds such as the following.

That is, the present invention uses the following components (a) and (b) (a) of the general formula [I], where m and n are O or a positive integer, and man is 2 or more. ] A vinyl ether compound represented by the following, in which R has the structure of any one of the following (1), (2), or (3).

Or a structure in which some of the hydrogen atoms of these aromatic rings are substituted with a halogen atom or an alkyl group having 4 or less carbon atoms.

[Here, R' is -CR1R"--3O, -5-CO-
or -8-, and R1 and R2 are a hydrogen atom, a methyl group, an ethyl group, or a phenyl group. ] [Here, p is a positive number of 1 or more, 9 is a positive number of 2 or more,
R3 represents a hydrogen atom, a halogen atom, or an alkyl group having 4 or less carbon atoms.] (b) A polythiol compound represented by the general formula R'-(SH)r.

[Here, R4 represents a polyvalent organic group, and r represents an integer of 2 or more. ] It is a photocurable composition characterized by consisting of the following.

The vinyl ether compound constituting the present composition is represented by the above general formula [1], and a compound in which R has the structure (1) is CH,=CH0C2H40be◇published by H,0CH= CI(
2CH,=CH0C,H,o@9oc,+(40CH=
CH.

CH2=C)IOC,H4o@-s-OocmH,0C
)I=(,H□CH2=CH0C,H,O@-5@-Q
C, H4QC) I=CH.

can be exemplified, and as a compound where R has the structure (2),
An example is a condensate produced by a dehydrochlorination reaction between a phenol resin and 2-chloroethyl vinyl ether.

Further, as the compound having the structure (3) as the above-mentioned R, for example, a condensate obtained by a dehydrochlorination reaction of poly(paravinylphenol) or brominated poly(paravinylphenol) and 2-chloroethyl vinyl ether. I can list them.

On the other hand, the polythiol compound shown in (b) has the general formula R
'-(SH)r [where R4 and r are the same as above. ] However, it is preferable that the vinyl ether compound is substantially soluble together with the vinyl ether compound at room temperature or in a heated state, either as it is or in a solvent or plasticizer that is inert to both.

Examples of these are: (1) SotL Soh R11J Number 2-10 (7)
SH-R'-COOH organic acid and R” (Of()s
Esters from polyhydric alcohols or phenols (H
3R'Coo)sR'(2)(H9R' 0)sR
'[RG is an aliphatic residue having 2 to 20 carbon atoms and may contain a petro atom, R7 is an aliphatic residue having 1 to 20 carbon atoms,
S represents a natural number from 2 to 20. ] etc. Specific examples of these include pentaerythritol tetrakis (thioglycolate), pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), ethylene glycol bis(thioglycolate), 1 ,2-dimercaptoethane,1,
Examples include 8-dimercapto-3,6-thioxaoctane, trimercaptobenzenes, tri(2-lcaptoethyl)benzenes, and the like.

The ratio of the vinyl ether compound to the polythiol compound constituting the composition of the present invention is such that the equivalent ratio of the latter thiol group to the former vinyl ether group is preferably 0.3 to 1.8, more preferably 0.8 to 1.2. . This equivalence ratio is 0.
If it is less than 3 or more than 1.8, the curing speed, which is one of the characteristics of the present invention, will be low, and the strength of the cured product will be insufficient, so both are not preferred.

Furthermore, when using a photosensitizer, it is usually sufficient to use it in an amount of 10% by weight or less based on the weight of the vinyl ether compound.

As mentioned above, the composition of the present invention essentially comprises the vinyl ether compound represented by the general formula [I] and the polythiol compound represented by the general formula [II], but in addition to these compounds, the composition It goes without saying that other components may be added during or after curing unless they have an undue adverse effect; for example, vinyl ether compounds with other structures may be added for reasons such as further improvement of workability. Antioxidants, hardening accelerators, fillers, etc. can also be added as necessary.

"Example" Examples and comparative examples are given below to explain the composition of the present invention in more detail. In the following examples, the ambient temperature during ultraviolet irradiation is room temperature.

Example 1 (Production example of vinyl ether compound (A)) 343 g of 2.2-bis(4-hydroxyphenyl)propane, 600 g of toluene, 151 g of sodium hydroxide, 600 g of 2-chloroethyl vinyl ether and 33.8 g of tetraethylammonium bromide were added. The reaction was carried out at 90-95°C.

After separating the catalyst and salt from the produced solid, the product was purified by recrystallization using n-hebutane, and the melting point was 56-57.
480 g of white crystalline material was obtained.

The infrared spectrum and NMR spectrum revealed that this crystalline substance was vinyl ether (A) having the following structure.

The purity of this product was 99.5% based on gel permeation chromatogram (GPC).

(Example of curing of compound (A)) 7.3 g of this compound (A) and 4.7 g of pentaerythritol tetrakis (3-mercaptopropionate) are mixed and heated at 50 to 60°C and stirred to form a homogeneous liquid. This composition was obtained.

When this liquid was applied to a thickness of about 10μ on a copper-clad laminate and a glass plate and irradiated with a 500V high-pressure mercury lamp from a distance of 25 al, it cured in a few seconds even though no sensitizer was added. A reaction occurred.

When we measured the shortest time (tack-free time) until the surface no longer felt sticky by changing the irradiation time, we found that the tack-free time was almost the same for both copper-clad laminates and glass plates, which was 5 seconds. .

Example 2 Adding benzophenone to the composition of Example 1.

The method described in Example 1 was repeated to measure the tack-free time.

The amount of benzophenone added is 2% by weight (0% by weight) based on the composition.
, 24g), the tack-free time is 2 seconds, 5% by weight (
0.6g), the time was less than 1 second.

Comparative Example 1 Diethylene glycol divinyl ether (boiling point 94°C/6mmHg) was used in place of the compound (A) used in Example 1.
3. Ig was irradiated with ultraviolet rays under the same conditions as in Example 2, and the tack-free time was measured.

Approximately 7 seconds when adding 2% by weight of benzophenone, 5% by weight
In the case of , it was about 4 seconds.

Comparative Example 2 In place of the vinyl ether compound (A) of Example 1, 6.2 g of the following compound was used and irradiated with ultraviolet rays under the same conditions as in Example 2, and the tack-free time was measured.

When using pensive enone 2-weight stone as a sensitizer, about 8
It was as long as 4 seconds even when 5% by weight was used.

Example 3 Pentaerythritol tetrakis (3
Example 1 or 2: 3.6 g of trimethylolpropane tris(thioglycolate) (Michler's ketone was used as the sensitizer) in place of mercaptopropionate)
The tack-free time was measured by irradiating ultraviolet light under the same conditions as above. The time was about 6 seconds when no sensitizer was used, about 2 seconds when 2% by weight of the sensitizer was used, and about 1 second when 5% by weight of the sensitizer was used.

Example 4 (Production example of vinyl ether compound (B)) The following compound (B) was produced in the same manner as in Example 1 using bis(4-hydroxyphenyl)sulfone.

The melting point is 119°C and the purity determined by GPC is 9
It was 9.7%.

(B) (Example of curing of compound (B)) 7.8 g of compound (B) and 3.8 g of trimethylolpropane tris(3-mercaptopropionate) were mixed,
After heating and dissolving at 110 to 120°C, tack-free time was measured by irradiating ultraviolet rays under the conditions described in Examples 1 and 2. It takes 5 seconds when no sensitizer is added, and about 2 seconds when 2% by weight of benzophenone is added.

When 5 parts by weight were added, the time was about 1 second.

Example 5 (Production Example of Vinyl Ether Compounds C) Using a method similar to Example 1, the compounds shown in Table 1 were produced. However, depending on the compound, a polar solvent such as DMS○ was used as the solvent, and when the compound was an acid, a potassium salt was used.

(Example of curing of compound (C)-(I)) The above compound and pentaerythritol tetrakis (3-
Mercaptopropionate) was mixed so that vinyl ether groups and thiol groups were equivalent, heated in some cases to make it liquid, applied in the same manner as in Example 1 or 2, irradiated with ultraviolet rays, and measured the tack-free time. did. The results are shown in Table 2.

Table 2 Example 6 (Production example of vinyl ether compound (J)) Using N,N'-diacetylacetamide as a solvent and tetraammonium bromide as a catalyst, a novolak type phenol resin (BRG-555 manufactured by Showa Kobunshi Co., Ltd.) .Molecular weight 415, OHV1
03) 200g, z-'7ooz chill vinyl ether 4
The reaction was carried out using 27 g of sodium hydroxide and 104 g of sodium hydroxide at a reaction temperature of about 80-90°C. After the generated sodium chloride was filtered off, 2-chloroethyl vinyl ether that had not reacted with the solvent was distilled off and collected.

The residue was washed with water and hexane and dried to obtain 340 g of a product that was liquid at room temperature. Almost no absorption based on hydroxyl groups is seen in the infrared spectrum of this product, and 980-
11 and 1610-”a++ have absorption based on vinyl groups,
Absorption based on ether bonds was observed at 1200'''1 cm i and 1240''1 cm i.

Furthermore, in GPC analysis of this product, three peaks of those used as raw materials were shifted to the polymer side, and the number average molecular weight was measured to be 550.

From the above results, it was found that in this product, the hydroxyl groups of the phenolic resin used as a raw material were almost quantitatively converted to vinyloxyethyl groups. or.

The average equivalent weight of this product per mole of vinyloxyethyl groups was calculated to be about 170.

(Example of curing of compound (J)) 17 g of the above product and 9.7 g of 1,8-dimercapto-3,5-dioxaoctane were mixed and irradiated with ultraviolet rays according to the method described in Example 1 or 2. When measured, the time was 4 to 5 seconds without a sensitizer, about 2 seconds when using 2d@wt% of benzophenone, and 1 second or less when using 5% by weight of benzophenone.

Example 7 (Production example of vinyl ether compound (K)) p-ethylphenol 65%, p-cresol 4%, phenol 1%
and p-vinylphenol 30% mixture 150
g, 2-chloroethyl vinyl ether 325g Residue obtained by treating the reaction product as in Example 6 with 120g of sodium hydroxide and a catalytic amount of tetrabutylammonium bromide in a toluene solvent at 50-60°C. The product was dissolved and purified in methanol to obtain 81 g of an insoluble portion with a melting point of about 40°C.

GPC analysis of this solid showed one peak and a molecular weight of 5,530. Infrared analysis also revealed that the peaks based on hydroxyl groups disappeared and peaks based on vinyl groups and ether groups appeared, and from these it was determined that this solid was poly(4-vinyloxyethoxy)styrene.

(Example of curing of compound (K)) Poly(4-vinyloxyethoxy)styrene 19.
5 g of 1,8-dimercapto-3,5-dioxaoctane and 9.7 g of 1,8-dimercapto-3,5-dioxaoctane were mixed and the method described in Example 7 was repeated.

The tack-free time was about 4 seconds when no sensitizer was used, about 1 second when using 2% by weight of benzophenone, and less than 1 second when using 5% by weight of benzophenone.

Claims (1)

[Scope of Claims] 1. A photocurable composition comprising the following components (a) and (b). (a) General formula [ I ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ −−−−−− [ I
] [Here, m and n are 0 or a positive integer, and m+n is 2 or more. ] A vinyl ether compound represented by the following, in which R has the structure of any one of the following (1), (2), or (3). (1) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [m, n is a natural number, and m+n indicates 2 or more. ] Or a structure in which some of the hydrogen atoms of these aromatic rings are substituted with a halogen atom or an alkyl group having 4 or less carbon atoms. [Here, R' is -CR^1R^2-, -SO_2-,
-CO- or -S-, and R^1 and R^2 are a hydrogen atom, a methyl group, an ethyl group, or a phenyl group. ] (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (3) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [Here, p is a positive number of 1 or more, q is a positive number of 2 or more,
R^3 represents a hydrogen atom, a halogen atom, or an alkyl group having 4 or less carbon atoms. ] (b) A polythiol compound represented by the general formula R^4-(SH)_r. [Here, R^4 represents a polyvalent organic group, and r represents an integer of 2 or more. ]