JPS63314226A - Photopolymerizable rubber composition - Google Patents

Abstract

PURPOSE:To obtain a photopolymerizable rubber composition which can give a flexible solvent-insoluble cured product excellent in both tensile strength and elongation, by mixing a specified photopolymerizable rubber with a photosensitizer, an addition-polymerizable monomer and a thermal polymerization inhibitor and reacting the mixture. CONSTITUTION:A rubber composition obtained by homogeneously mixing 100pts. wt. composition (i) based on a component of the formula (wherein R is a 2-8C alkylene group, R1 is H or CH3, R2 is a diisocyanate residue, R3 is a residue derived by removing the hydroxyl groups from a dihydric alcohol, X is a part derived by removing the hydroxyl group from a hydroxylated liquid diene rubber, l is 1-4, 1<m<4, and n=1-16) with 1-10pts.wt. photosensitizer (ii), 10-300pts.wt. addition-polymerizable monomer (iii) and 0.01-0.1wt.%, based on the total of components (ii) and (iii), thermal polymerization inhibitor and reacting the mixture. This photopolymerizable rubber composition can be used as a material for high-elasticity inks, high-elasticity paints, flexographic plate materials, etc.

Description

[Detailed description of the invention] The present invention relates to photopolymerizable rubber compositions.

Photopolymerizable rubber compositions obtained by reacting diene liquid rubbers having hydroxyl groups, ethylenically unsaturated monomers having hydroxyl groups, and isocyanate compounds are already known. It is also known to add a photosensitizer or the like to the composition to increase photocurability, or to add a thermal polymerization inhibitor or the like to prevent gelation during storage.

(Unexamined Japanese Patent Publication No. 56-86903).

However, the photocured product of the above composition has low tensile strength, is brittle, and has a low elongation rate. Therefore, there were many disadvantages in applications requiring a flexible cured product.

In order to eliminate such drawbacks, the present inventors used a dihydric alcohol with a molecular weight of 12,000 or less in the above formulation, and the tensile strength of the photocured product was significantly improved by 4 to 10 times. It was discovered that a photocured product can be obtained. In addition, a photocured product with surprisingly improved properties, showing elongation rates of 2 to 20 times or more, could be obtained.

The rubber that constitutes the main component of the present invention is obtained by reacting a diene liquid rubber having a hydroxyl group, an ethylenically unsaturated monomer having a hydroxyl group, a dihydric alcohol having a molecular weight of 12,000 or less, and further a diisocyanate compound. It is a photopolymerizable rubber with a hard segment having a urethane bond consisting of a dihydric alcohol with a molecular weight of 12,000 or less and a diisocyanate compound, and a photocrosslinking point from an ethylenically unsaturated monomer having a hydroxyl group bonded to the hard segment and the rubber. It has a structure consisting of soft segments consisting of molecular chains.

The photopolymerizable rubber composition of the present invention has a general formula;
or CH,, R, is a diisocyanate residue, R, l is 2
The residue of the alcohol after removing the hydroxyl group,
．． 1<m<4. 1 to 1 parts by weight of the photosensitizer per 100 parts by weight of the present composition mainly consisting of components represented by n=1 to 16).
0 parts by weight and 0.01 to 0.1% by weight of a thermal polymerization inhibitor based on the total weight of the mixture of 10 to 300 parts by weight of an addition polymerizable monomer and reacted. A photopolymerizable rubber composition characterized in that it is a photopolymerizable rubber composition.

Examples of the diene liquid rubber having a hydroxyl group used in the present invention include 1,2-polybutadiene, 1,4-polybutadiene, 1,2-pentadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and acrylonitrile-butadiene copolymer. Number average molecules such as gen copolymers 1100
It is a polymer of about 0 to 10,000, and the position of the hydroxyl group is arbitrary. In addition, the number of hydroxyl groups in the molecule (m) is 1<m<
It is 4. When m≦1, the photopolymerization density becomes low and the photocured product becomes brittle.

Furthermore, when m≧4, the material becomes hard and the elasticity decreases, which is not good.

To produce the photopolymerizable rubber which is the main component of the present invention, one or more diene liquid rubbers having hydroxyl groups are blended.

Examples of the ethylenically unsaturated monomer having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,
Examples include polypropylene glycol monomethacrylate, and in the present invention, one or more ethylenically unsaturated monomers having hydroxyl groups are required to be used in an amount of 2 to 25 parts by weight per 100 parts by weight of liquid rubber.

Examples of diisocyanate compounds include tolylene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, lysine diisocyanate, and hydrogenated tolylene diisocyanate. Or two or more types of liquid rubber 10
It is necessary to distribute 5 to 190 parts by weight relative to 0 parts by weight.

Further, dihydric alcohols with molecules of 12,000 or less used in the present invention include ethylene glycol, diethylene glycol, triethylene glycol, 1°2-propylene glycol, 1,3-propylene glycol, 1,3-
Butanediol, 1,4-butanediol, 1,5-bentanediol, 1,6-hexanediol, dioxane glycol (trade name: manufactured by Mitsubishi Gas Chemical Co., Ltd.),
As the dihydric alcohol having a molecular weight of 2000 or less, a dihydric alcohol having an ethylenically unsaturated monomer can be used.

As a dihydric alcohol having an ethylenically unsaturated group,
There are trimethylolpropane monoacrylate, trimethylolpropane monomethacrylate, glycerol α-monoallyl ether, etc., and it is necessary to use one or more of these in an amount of 1 to 90 parts by weight per 100 parts by weight of liquid rubber.

The blending ratio of the above components is, for example, when the repeating unit n (n is explained below) is 1, the molecule ff is 12,000 or less per mole of diene liquid rubber having a hydroxyl group with a valence of 2 in one molecule. 2 moles of a dihydric alcohol, 4 moles of a diisocyanate compound, and 2 moles of an ethylenically unsaturated monomer having a hydroxyl group. Also, n=2~
In the case of 16, the molecule ff120 per mole of diene liquid rubber having a hydroxyl group with the valency (m) of the hydroxyl group in one molecule.
00 or less, preferably 300 or less dihydric alcohol mX
n moles, mX (n+1) moles of the diisocyanate compound, and m moles of the ethylenically unsaturated monomer having a hydroxyl group.

Taking all of the above into consideration, it is necessary to produce the photopolymerizable rubber which is the main component of the present invention.
), an ethylenically unsaturated monomer B having a hydroxyl group, a dihydric alcohol C having a molecular weight of 12,000 or less, and a diisocyanate compound in a blending ratio A:B:C:D of 1 : m : m x n : m

The blending ratio for producing the photopolymerizable rubber of the present invention is within the range of the above-mentioned blending ratio of the photopolymerizable rubber composition, and specifically, it is preferable to blend the following weight ratios.

A, 100 parts by weight of diene liquid rubber having a hydroxyl group B, 2 to 25 parts by weight of an ethylenically unsaturated monomer having a hydroxyl group C0 molecule 1t 1 to 90 parts by weight of a dihydric alcohol having a mass of 2000 or less, a diisocyanate compound 5 to 190 parts by weight! To explain the synthesis outline for producing the photopolymerizable rubber which is the main component of the composition of the present invention, the molecule ff120
00 or less in a ratio of 16 moles of dihydric alcohol to 18 moles of diisocyanate, and if necessary, dibutyltinlaurate, stanasoftate, triethylamine,
Add a urethane catalyst such as triethylene diamine. In this case, the temperature during the reaction is 0 to 120°C, preferably 4°C.
It should be between 0 and 80''C. In this way, a compound having isocyanate groups at both ends is obtained.

Subsequently, the compound thus obtained was reacted with 2 moles of an ethylenically unsaturated monomer having at least one hydroxyl group to form a compound having isocyanate-t4 at one end, and this was then reacted with a diene compound having a divalent hydroxyl group. liquid rubber 1
Add moles. The above reaction can also be carried out in a suitable solvent.

To make the rubber composition of the present invention, hydroquinone, t
-Butylcatechol, 0-dinitrobenzene, 0-dinitrophenol, m-nitrophenol, p-nitrophenol, 2.4-dinitrophenol, 2.4.6-
) A thermal polymerization inhibitor such as dinitrophenol or ferric chloride is added in an amount of 0.05 to 1% by weight based on the total weight of the mixture and reacted. The temperature at this time is 0 to 90°C, preferably 40 to 80°C.
It should be C. Through the above reaction, a photopolymerizable rubber composition that is an acryloyl rubber, a methacryloyl rubber, or a mixture thereof is synthesized.

The main components of the composition of the present invention can be represented by the following formula.

......(I) However, R is an alkylene group having 2 to 8 carbon atoms, R is H or CH3, Rt is a diisocyanate residue, R3 is a residue of a dihydric alcohol excluding the hydroxyl group, X is the part of the diene liquid rubber having hydroxyl groups from which hydroxyl groups have been removed, f is 1 to 4, m
is the valence of the hydroxyl group of the diene liquid rubber having a hydroxyl group, m
is l<m<4, n=1 to 16°, where n is the diisocyanate compound and the molecule 1200
It is the number of repeating units of urethane bond consisting of 0 or less dihydric alcohol, and means the length of the part forming the hard segment with respect to the rubber molecular chain (soft segment). The long hard segment is formed by a series of urethane bonds with high polarity and cohesiveness, and causes microscopic phase separation from the rubber molecular chains with low polarity and low cohesiveness. Further, it provides dense crosslinking through the photopolymerizable ethylenically unsaturated monomer attached to the hard segment. As a result, the photopolymerizable rubber composition of the present invention can be photocured with high strength and high elongation upon irradiation with light. When using a dihydric alcohol with a molecular ff of 12,000 or more,
This is not preferable because it becomes difficult to cause phase separation between the hard segment and the soft segment, and the intended purpose of the present invention cannot be achieved. The preferred molecular weight is 2000 or less, particularly 300 or less.

In addition, in the case of a formulation where the number of repeating units n is n>16,
It does not lose its rubber-like properties, which is not desirable.

The photopolymerizable rubber that is the main component of the present invention is expressed by the following formula (
It is characterized by being composed of two segments: a hard segment (n) and a soft segment consisting of X in formula (1), that is, a diene liquid rubber skeleton.

・・・・・・・・・(II) Here, R2 is a diisocyanate residue, R3 is a residue of dihydric alcohol excluding the hydroxyl group, n = 1 to 16°, where the molecular weight is 12,000 or less, preferably 300 or less is introduced into the backbone of the hard segment component of formula (n).

The hard segment consists of a continuous chain length of urethane bonds, and is a factor that causes physical bonds such as hydrogen bonds and van der Waals forces. In contrast, soft segments do not have these binding forces and are amorphous.

The intermolecular arrangement of the hard segments of the photopolymerizable rubber, which is the main component of the present invention, is illustrated in FIG. 1. The parts in the figure indicate physical bonding forces such as urethane bonds, dihydric alcohol residues, ethylenically unsaturated monomers, diene liquid rubber, etc., such as hydrogen bonds.

In addition, in the production of the photopolymerizable rubber composition of the present invention, a photosensitizer and an addition polymerizable monomer are appropriately added alone or in combination to the photopolymerizable rubber described above. Add the above-mentioned thermal polymerization inhibitor in an amount of 0.05 to 1% by weight based on the total blended amount, and react at 0 to 90°C, preferably 40 to 80°C, to form a rubber acroyl, methacryloyl, or these. A photopolymerizable rubber composition which is a mixture of It is appropriate to add 0.01 to 1% by weight of the total amount of the thermal polymerization inhibitor to the composition of 10 to 300 parts by weight.

Here, as the photosensitizer, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin butyl ether, benzophenone, Michler's ketone, 1-naphthalenesulfonylchloride l', 2.5
-Naphthalene disulfonyl chloride, 2-naphthalene sulfonyl chloride, azoisobutyronitrile, 1-
arabis-1-cyclohexanecarbonitrile, benzyl dimethyl ketal, 2-methylanthraquinone, biimidazole, thioxanthone, 2,4-diisopropylthioxanthone, 2,2-jethoxyacetophenone,
Examples include benzoyl peroxide and 2,4-dichlorobenzoyl peroxide.

In addition, addition polymerizable monomers include the ethylenically unsaturated monomers having a hydroxyl group, methyl methacrylate, ethyl methacrylate, butyl methacrylate, glycidyl methacrylate, 1,4-butylene dimethacrylate, ethylene glycol dimethacrylate, diethylamino Methacrylates such as ethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, lauryl acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, 1,6-
Acrylates such as hexanediol diacrylate and diethylaminoethyl acrylate, methacrylic acid, acrylic acid, acrylonitrile, acrylamide, N-methylolacrylamide, styrene, vinyltoluene,
Divinylbenzene, α-methylstyrene, vinyl acetate,
Examples include N-vinyl-2-pyrrolidone and diallyl phthalate.

The photopolymerizable rubber composition of the present invention is characterized in that the photocured product is rubber-like and exhibits high tensile strength and high elongation.

According to the photopolymerizable rubber composition of the present invention, a flexible, solvent-insoluble photocured product with excellent tensile strength and elongation can be obtained, and can be used as high elastic ink, high elastic paint, flexo plate material, etc. be able to.

Next, the present invention will be explained in detail with reference to examples.

XUL example - 29.2g of rTD I J to 87.6g of dioxane
CrTDT.

A solution of 3 times the amount by weight) was put into a 500 mp reactor, and while stirring under a nitrogen atmosphere, 1.4
-butanediol 7.5g dioxane 22.5g (1
, 3 times the weight of 4-butanediol) was added dropwise, the temperature of the reaction solution was kept at 45 to 50° C. during the dropwise addition, and even after the dropwise addition was completed, the reaction was continued at the same temperature for 8 hours. Then rHEMAJ 10.8g, hydroquinone 0.15
g, a solution of 0.075 g of triethylenediamine dissolved in 33 g of dioxane (3 times the amount based on the weight of HEMAJ) was added dropwise, while the temperature of the reaction solution was kept at 75-80°.
The reaction temperature was maintained at 40° C., and the reaction was continued for 2 hours at the same temperature after the completion of the dropwise addition. Furthermore, 100g of liquid rubber rR-45DJ was added to dioxane 3
00 g (3 times the amount based on the weight of the liquid rubber) was placed in another 10100 O capacity reactor, and the reactant was added dropwise while stirring under a nitrogen atmosphere, during which time the temperature of the reaction solution was kept at 75. The temperature was maintained at ~80°C, and after the completion of the dropwise addition, the reaction was allowed to proceed at the same temperature for 8 hours, and it was confirmed that the absorption of isocyanate groups had disappeared using an infrared absorption spectrum, and the reaction was completed.
n-hexane 540Qij! (About 9 times the volume of the reaction solution)
While stirring, the reaction solution was gradually dropped into a beaker containing 100 ml of water, and a white precipitate was obtained. The thus obtained precipitate was dried in a vacuum dryer for 2 days after removing the solvent layer by a decanting method. After drying, solid urethane acrylate was obtained. This urethane acrylate corresponds to the photopolymerizable rubber composition described in claim 1 of the present invention. (The same applies in the following examples) Dissolve this urethane acrylate in tetrahydrofuran,
Add 5% Irgacure 651 as a sensitizer and add Te'lf1.
%1 to prepare a photosensitive solution. This photosensitive solution was applied to a glass plate, and the tetrahydrofuran was evaporated to dryness.

The thickness after drying was 100 μm. Ultra high pressure mercury lamp 3K
W (manufactured by Oak Co., Ltd.) was placed at a distance of 50 cm and exposed for 2 minutes to obtain a cured film. The tensile strength and elongation of the cured film were determined using a tensile tester (tensile speed: 100 mm/min). The measurement result was a tensile strength of 132 kg/cm.
, the degree of elongation was 210%.

Urethane acrylate was obtained in the same manner as in Example 1, except that the liquid rubber used in Example 1 and the type of dihydric alcohol having a molecular weight of 12,000 or less were changed. Examples 2 to 9 are collectively shown in Table 1. Here, the weight of the liquid rubber is 100 g.

Examples 10 to 12 of formulations in which the number n of repeating units of the hard segment described above is increased are shown below.

Implementation U An example of the number of repeating units n-2 is shown. 48.4 g of TDI was mixed with 145.2 g of dioxane (3 to 1 weight of TD).
A solution of 1.4 butanediol 16
．． 6 g of dioxane, 0.02 g of hydroquinone, and 0.02 g of triethylenediamine, and 49.8 g of dioxane (
A solution of 3 times the weight of 1,4-butanediol was added dropwise, and the temperature of the reaction solution was kept at 75 to 80"C.
After the completion of the dropwise addition, the reaction was continued at the same temperature for 2 hours. Next, a solution of 10.8 g of 2-hydroxyethyl methacrylate 1-1 dissolved in 32.4 g of dioxane was added to the same reactor, and the mixture was reacted at 75 to 80'C for 2 hours with stirring under a nitrogen atmosphere. Furthermore, liquid rubber JSR-HTPB100g
A solution of 300 g of dioxane (3 times the amount based on the weight of the liquid rubber) was placed in another 1000 d reactor.
While stirring in a nitrogen atmosphere, the reaction solution was kept at 75 to 80°C during the dropwise addition of the pre-reactant through the dropping funnel, and after the completion of the dropwise addition, the reaction was continued at the same temperature for 6 hours. (7) The reaction was terminated after confirming that absorption had disappeared.

The reaction solution was purified with hexane and dried in the same manner as in Example 1, and a tensile test piece was prepared. The physical properties of the cured film were measured to have a tensile strength of 165 kg/c+w'' and an elongation of 350%.

Next, Table 2 shows examples where the number of repeating units n=8 and 12. Here, the weight of liquid rubber is ioo g.

1 Yu'' ■ Souji U Addition polymerizable monomers were added and dissolved in the urethane acrylate obtained in Examples 1, 4, and 5.11, and 5% of the total weight of Irgacure 651 was added as an exacerbating agent to form a photosensitive solution. adjusted. This photosensitive solution was dropped onto a glass plate, spread to a thickness of 100 μm using an applicator, and exposed in the same manner as in Example 1 to determine the tensile strength and elongation of the cured product. This is Example 13
It is shown in Table 3 as ~17. Here, the weight of the urethane acrylate is 100 g.

Table 3 7) N-vinyl-2-pyrrolidone was abbreviated as rNVPJ.

8) Diethylaminoethyl methacrylate as rDEAM
It was abbreviated as AJ.

A relief was created using the photosensitive liquid formulated in Example 14 of the JJ Soil Rule. The photosensitive solution formulated in Example 14 was dropped onto a polyethylene terephthalate film whose surface had been grained, and the film was covered with a silicone-treated polyethylene terephthalate film to adjust the thickness of the photosensitive layer to 200 μm. Place a negative film on top of the cover film and apply 3KW of ultra-high pressure mercury lamp (newly manufactured by Oak Seisaku Co., Ltd.) for 30 minutes.
It was placed at a distance of cm and exposed for 30 seconds. After exposure, the cover film was peeled off and sprayed with a mixed solution of dioxane and ethanol (mixing ratio -1 = 2).The unexposed areas were easily eluted, and the exposed areas did not swell and the image lines on the negative film were removed. We were able to create a relief that reproduced the

2.4-) 28.4 g of lylene diisocyanate (hereinafter abbreviated as rTD1°) was mixed with 85.2 g of dioxane (rTD1°).
50% of the solution dissolved in 3 times the weight of the TD IJ type
2-hydroxyethyl methacrylate (rHE
It is abbreviated as "MA". ) 21.2g to dioxane 63.6g
g (3 times the volume relative to the weight of r HEMAJ) was added dropwise, while the temperature of the reaction solution was kept at 45~50''C.
After the dropwise addition was completed, the reaction was continued at the same temperature for 2 hours. After that, Poly bdLM-10 (hydroxyl group-terminated polybutadiene rubber, average molecular weight 1120, hydroxyl group content 1.68
meq/g Idemitsu Petrochemical Co., Ltd. 100 g, hydroquinone 0.15 g and triethylenediamine 0.0
75 g to 300 g of dioxane (300 g of liquid rubber weight)
Put the solution dissolved in 1000 d volume) into another 1000 d reactor, and dropwise add the above reactant while stirring under nitrogen atmosphere. During this time, keep the temperature of the reaction solution at 75-80°C, and after the completion of the dropwise addition, was also reacted at the same temperature for 8 hours, and it was confirmed that the absorption of isocyanate groups disappeared in the infrared absorption spectrum.
The reaction has ended.

n-hexane 5400mj! (About 9 times the volume of the reaction solution)
While stirring, the reaction solution was gradually dropped into a beaker containing 100 ml of water, and a white precipitate was obtained. The thus obtained precipitate was dried in a vacuum dryer for 2 days after removing the solvent layer by a decanting method. After drying, liquid urethane acrylate was obtained. Irgacure 651 (manufactured by Nippon Ciba Geigy Co., Ltd.) is used as a sensitizer in this urethane acrylate.
A 5% solution was prepared by adding and dissolving it. Drop this liquid on the glass plate and apply 100p with an applicator.
It was rolled out to m thickness. A 3KW ultra-high pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd.) was placed at a distance of 50 am, and exposed for 5 minutes to obtain a cured film. Tensile testing machine (tensile speed 100mm/min
) was used to determine the tensile strength and elongation of the cured film.

The measurement results were a tensile strength of 6 kg/(m2) and an elongation of 75%.

Comparative Example 1 by changing the type of liquid rubber used in Comparative Example 1
Urethane acrylate was obtained in the same manner as above. They are shown in Table 4 as Comparative Examples 2 to 5. Here, the liquid rubber weight is 10
Set to 0g.

↓Note Commercially available urethane acrylate rPoly bdR-45
A tensile test piece was prepared in the same manner as in Comparative Example 1 by adding 5% of the aggravating agent Irgacure 651 to ACRJ (manufactured by Idemitsu Petrochemical Co., Ltd.), and the tensile strength and degree of elongation were determined. The results were a tensile strength of 44 kg/cm'' and an elongation of 168%.

As explained above, the photopolymerizable rubber composition of the present invention is composed of a diene liquid rubber having a hydroxyl group, an ethylenically unsaturated monomer having a hydroxyl group, a dihydric alcohol having a molecular weight of 2000 or less, and a diisocyanate compound. [Has a hard segment with a urethane bond consisting of a dihydric alcohol of 2000 or less and a diisocyanate compound, and a soft segment consisting of a rubber molecular chain and a photocrosslinking point from an ethylenically unsaturated monomer having a hydroxyl group bonded thereto. Has a structure. In addition, the photocured product is rubber-like and exhibits high tensile strength and elongation, and can be used as a new material for high elastic inks, high elastic paints, flexographic printing materials, etc.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the arrangement of hard segments in the photopolymerizable rubber composition of the present invention.

Claims (1)

[Claims] 1. General formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R is an alkylene group having 2 to 8 carbon atoms, R_1 is H or CH_3, R_2 is a diisocyanate residue, R_
3 is the residue of the dihydric alcohol with the hydroxyl group removed, X is the part of the diene liquid rubber having the hydroxyl group with the hydroxyl group removed, l is 1 to 4, 1<m<4, n=1 to 16) 1 to 10 parts by weight of photosensitizer per 100 parts by weight of the composition mainly consisting of
0.01 to 0.1% by weight of thermal polymerization inhibitor based on the total weight of the mixture of 10 to 300 parts by weight of addition polymerizable monomer
1. A photopolymerizable rubber composition obtained by uniformly mixing and reacting.