GB2178436A - Photosensitive polymer of rubber - Google Patents

Abstract

A photosensitive polymer which comprises soft segments of a dienic liquid rubber having hydroxyl groups with hard segments of the urethane bond derived from an ethylenically unsaturated monomer having hydroxyl groups, a dihydric alcohol of molecular weight less than 2,000, and diisocyanate compound, of the formula:- <IMAGE> wherein, R = an alkyl group having 1 SIMILAR 8 carbon atoms, R1 = H or CH3, R2 = a diisocyanate residue, R3 = a residue excluding hydroxyl group of dihydric alcohol, X is a dienic liquid rubber having hydroxyl groups removed, l = 1-4, n = a length of hard segments </=16, and m is a valence of hydroxyl groups of said liquid rubber and 1<m<4.

Description

SPECIFICATION Photosensitive polymer of rubber Field of the invention High Molecular Compound International Patent Class: CO8F Background of the invention The present invention relates to a photosensitive Polymer of rubber which particularizes desirably the character of the conventional photocured composition.

The conventional photocured products does not meet the needs of these days in which the polymer having essentials of high flexibility and high tensile strength is especially required because such conventional ones are, in general, physically brittle and low in elongation.

The object of the present invention is to get rid of the defect mentioned above.

Summary of the invention The photosensitive polymer of rubber pertaining to the present invention provides a dienic liquid rubber as an element of soft segments on the one hand and the other part as hard-segments formed by an urethane bond consisting of an ethylenically unsaturated monomer having hydroxyl groups, a dihydric alcohol having maximum molecular weight, and a diisocyanate compound. Each of these element is composed under the certain limitation and abovementioned both layers are minutely bonded.

Description of the preferred embodiment The present invention relates to the photosensitive polymer of rubber which particularizes desirably the character of the photocured composition.

The elements for the constitution of this invention are following materials forming so-called soft segments and hard segments, and such materials will be described first of all.

In soft segments, dienic liquid rubbers having hydroxyl groups in a molecule are undermentioned polymers having molecular weight of 1,000 - 10,000 and the position of the hydroxyl groups is arbitrary.

1,2-polybutadiene 1.4-polybutadiene 1,2-pentadiene styrene-butadiene acrylonitrile-butadiene Next, ethylenically unsaturated monomers in hard segments are already known, for example, 2-hydroxyethyl acrylate 2-hydroxyethyl methacrylate 2-hydroxylpropyl acrylate 2- hydroxylpropyl methacrylate polypropylene glycol monomethacrylate One of these materials can be selected.

And, dihydric alcohols having a limited molecular weight of less than 2,000 can be selected from the following table's one.

ethylene glycol diethylene glycol triethylene glycol 1,2-propylene glycol 1,3-propylene glycol 1,3-butanediol 1,4-butanediol 1,5-pentanediol 1,6-hexanediol dioxane glycol trimethylol propane monoacrylate trimethylol propane methacrylate glycerol-x-monoallyl ether Then, diisocyanate compounds can be also selected from the following.

tolylene diisocyanate xylylene diisocyanate napthalene diisocyanate hexamethylene diisocyanate isopholone di isocyanate 4,4'-diphenylmethane di isocyanate lysine diisocyanate hydrogenated tolylene diisocyanate Thus, in order to attain the object mentioned above of present invention, inventors executed the blend of above each material repeatedly and put a limitation as a result of the undermentioned test data.

That is, when the value of n, which is a length of a part forming the hard segment and is also a repeating unit number of urethane bond, is established as n = 1 and n = 2 - 16, the blending ratio of above materials in this pattern is set as next table.

Blending ratio of abovementioned each material at 40"C - 80"C Polymer of Soft segments: Hard segments: present invention limitation Dienic liquid rubber Ethylenically Dihydric alcohol Diisocyanate having hydroxyl unsaturated monomer (having a molecular compound groups of 2 valence having hydroxyl weight of less than (m = 2) groups 2,000) n = 1 1 mole 2 moles 2 moles 4 moles n = from 2 to 16 1 mole m moles mn moles m(n + 1) moles The reason why the valence of hydroxyl groups m should be set within the range of 1 < m < 4 is to prevent the photopolymerization density from lowering, in the addition, to prevent composition from over-hardening with attention so that physical character of composition does not become brittle.

However, the blending turn of the above is free and then, only the process must be carried out under preferable temperature (40"C--80"C).

Whereby a terminal isocyanate compound can be obtained.

And desirable rubber-like acryloyl compound and methacryloyl compound are obtained through the reaction process of adding 2 moles of abovementioned unsaturated monomer and 1 mole of abovementioned liquid rubber to the terminal isocyanate compound.

Thus, these rubber-like materials or the photosensitive polymer of rubber of present invention which is a compound of these can be formed.

Besides, in the process as is already described, the addition of a photosensitizer and/or a thermal polymerization inhibitor is allowable, and the means of adding such on-the-market chemicals are existing within the thought of this invention.

Meanwhile, the aforementioned value of n, the length of a part forming the hard segment is, as disclosed, the repeating unit number of urethane bond consisting of the diisocyanate compound, the dihydric alcohol having limited molecular weight, and the ethylenically unsaturated monomer; when the value of n increases, the polarity and cohesiveness of segment becomes relatively high and therefore, a phase separation from the rubber molecular chain having low polarity and cohesiveness is strongly caused.

According to the present invention, by the crosslinkage action provided to phto-polymerizable unsaturated monomers of the hard segment side through said separating action, the particular product of high strength and high-elongation in the essence, can be constituted.

The closeness of said crosslinkage is led by aftermentioned test (the embodiment) and will be described fully in said test.

In the disclosed embodiment (will be mentioned after), it can be understood that phase separation becomes weak and the rubber character of the polymer is spoiled considerably when increasing the molecular weight of the dihydric alcohol more than 2,000 and allowing the value of n to exceed 16.

Aforementioned construction of the rubber system bond of present invention belongs generally to the following formula pertaining to the functional acrylic monomer.

However, R of above formula upon the constitution of present invention is an alkyl group having 1 8 carbon atoms, then, e is within 1 4 and n is limited as n16 in X, a part where hydroxyl groups of the dienic liquid rubber having hydroxyl groups is removed.

In this pattern, R1 = H or CH3, R2 = a diisocyanate residue, and R3 = a residue excluding hydroxyl groups of dihydric alcohol.

Under the blending limitation of each basic materials, the constitution of this rubber-like polymer which provides two (2) layers (urethane bond and rubber molecular chain) of different cohesiveness in 1 < m < 4, having the novelty and inventive-step in the field.

In the abovementioned means of blend, however, optional introduction of one or more of various basic materials to compose two elements are allowable and then such blending know-how is known by a person with ordinary skill in the concerned art.

For the next discussion, many examples proving the constitution and the effect of present invention will be disclosed hereafter.

Comparative Example 1 A solution of 28.4 g of 2,4-tolylene diisocyanate (abbreviated as "TDI" hereinafter) in 85.2 g (three times as much as "TDI" weight) of dioxane was introduced into a reactor as 500 mf by volume and a solution of 21.2 g of 2-hydroxyethyl methacrylate (abbreviated as "HEMA" hereinafter) in 63.6 g (three times as much as "HEMA" weight) of dioxane was added dropwise thereto through a dropping funnel while stirring under an atmosphere of nitrogen. During the dropping, the reaction solution was maintained at 45-50"C. After completion of the dropwise addition, the solution was allowed to react at 45-50"C for 2 hours.Then, a solution of 100 g of poly bd LM-10 (polybutadiene rubber having terminal hydroxyl groups, the average molecular weight 1,120, hydroxyl groups content 1.63 meg/g, made by ldemitsu Sekiyu Kagaku Inc.), 0.15 g of hydroquinone and 0.075 g of triethylenediamine in 300 g (three times as much as the liquid rubber weight) of dioxane was introduced into a separate reactor of 1,000 me by volume and the above described reaction product was added to said separate reactor through a dropping funnel while stirring under an atmosphere of nitrogen. During the reaction material was added dropwise, the reaction solution was maintained at 75-80"C. After completion of the dropwise addition, the solution was allowed to react at 75-80"C for 8 hours.The disappearance of a peak of isocyanate groups was confirmed by the infrared spectrophotometer and the reaction was terminated.

The reaction solution was gradually introduced into a beaker containing 5,400 me (nine times as much as the reaction solution) of hexane while stirring the beaker to obtain a white precipitate. The precipitate purified by the use of hexane was allowed to dry for 2 days by a vacuum dryer. After the drying, liquid urethane acrylate was obtained. Irgacure 651 (a product of Nippon Ciba-Geigy Inc.) of 5% as a sensitizer was added to the urethane acrylate to prepare a photosensitive liquid. This photosensitive liquid was dropped on a glass plate and spread into 100 pm in thickness with an applicator and exposed to an ultra-high voltage mercury lamp of 3 KW placed at a distance of 50 cm from the plate for 5 minutes to obtain a cured film.The tensile strength and the elongation of the cured film were determined by a tension tester (the tension rate of 100 mm/min) to obtain the result of a tensile strength of 6 kg/cm2 and an elongation of 75%.

Comparative Examples 2-5 Urethane acrylates were obtained in the same manner in Comparative Example 1 by varying the kind of liquid rubber used in Comparative Example 1. The results are set forth in Table 1. The weight of a liquid rubber is 100 g.

TABLE 1 Compara- Dienic liquid rubbers having HEMA TDI Tensile Elongation tive hydroxyl groups (g) (g) strength ( /0) example Trade name Average Content of (kglcm2) molecular hydroxyl weight groups (meqig) 2 Poly bd R-45D') 2,800 0.83 12.1 14.5 20 73 3 Nisso-PBG-10002 1,350 1.18 15.4 20.6 16 50 4 Nisso-PB-6003 820 1.61 21.1 28.1 unable to measure for the brittleness 5 JSR-HTPB4 2,120 0.93 12.0 16.0 12 11 ') A product of Idemitsu Sekiyu Kagaku Inc., abbreviated as "R-45D".

2) A product of Nippon Soda Inc., abbreviated as "G-1 000".

3) A product of Nippon Soda Inc., abbreviated as "G-600".

4) A product of Nippon Gosei Gomu Inc., called as "JSR-HTPB".

Comparative Example 6 Irgacure 651 of 5% as a sensitizer was added to commercially available urethane acrylate "Poly bd R-45 ACR" (a product of ldemitsu Sekiyu Kagaku Inc.) and a tension test piece was prepared in the same manner as in Comparative Example 1 and the tensile strength and the elongation were dertermined.

Tensile strength: 44 kg/cm2 Elongation : 168% Test 1 A solution of 29.2 g of "TDI" in 87.6 g (three times as much as "TDI" weight) of dioxane was introduced into a reactor of 500 me and a solution of 7.5 g of 1,4-butanediol in 22.5 g (three times as much as 1,4-butanediol weight) of dioxane was added thereto through a dropping funnel while stirring under an atmosphere of nitrogen.

During the dropwise addition, the reaction solution was maintained at a temperature of 45-50"C. After completion of the dropwise addition, the solution was allowed to react at 45-50"C for 3 hours. Then, a solution of 10.8 g of "H EMA", 0.15 g of hydroquinone and 0.075 g of triethylenediamine in 33 g (three times as much as "HEMA" weight) of dioxane was added through a dropping funnel. During the dropwise addition, the reaction solution was maintained at 70-80"C. After completion of the addition, the solution was allowed to react at 75-80"C for 2 hours.Further, a solution of 100 g of a liquid rubber "R-45D" in 300 g (three times as much as the liquid rubber weight) of dioxane was introduced into another reactor of 1,000 me and the said reaction product was added through a dropping funnel while stirring under an atmosphere of nitrogen. During the dropwise addition, the reaction solution was maintained at 75-80"C. After completion of the addition, the solution was allowed to react at 75-80"C for 8 hours. The disappearance of a peak of isocyanate groups was confirmed by an infrared spectrum and the reaction was terminated.

5,400 me (nine times as much as the reaction solution) of hexane in a beaker was stirred while the reaction solution was added slowly into the beaker to obtain a white precipitate. The precipitate purified with the hexane was allowed to dry for 2 days by a vacuum dryer. After the drying, solid-like urethane acrylate was obtained. This urethane acrylate was dissolved in tetrahydrofuran and Irgacure 651 of 5% as a sensitizer was added and dissolved therein to prepare a photosensitive liquid. This photosensitive liquid was applied on a glass plate and tetrahydrofuran was evaporated to dryness. The thickness after the drying was 100 Rm and the film was exposed to an ultra-high voltage mercury lamp of 3 kw placed at a distance of 50 cm for 2 minutes, to obtain a cured film.

The tensile strength and the elongation of the cured film were dertermined by a tension tester (the tension rate of 100 mm/min) to obtain a tensile strength of 132 kg/cm2 and an elongation of 210%.

Tests 2-9 Urethane acrylate was obtained in the same manner as in Example 1 by varying the liquid rubber and dihydric alcohols having a molecular weight of less than 2,000 used in Example 1. The weight of a liquid rubber is 100 g.

TABLE 2 Example Dienic liquid rubber Dihydric alcohol having a molecular HEMA TDI Tensile Elonga having hydroxyl weight of less than 2,000 (g) (g) strength tion groups Kind weight {kg/cm) ( /0) (g) 2 JSR-HTPB dioxane glycol6) 20.4 12.0 32.3 130 412 3 JSR-HTPB glycerol-a-monoallylether 12.2 12.0 32.3 137 287 4 JSR-HTPB 1,2-propylene gycol 7.0 12.0 32.3 126 187 5 JSR-HTPB triethylene glycol 13.9 12.0 32.3 119 411 6 JSR-HTPB 1,4-butanediol 12.0 8.5 32.3 165 318 7 2M-10 1,4-butanediol 21.2 14.7 57.1 113 182 8 Poly bd LM-1 55) 1,4-butane diol 14.0 12.0 37.5 157 330 9 G-1000 1,4-butanediol 15.8 10.9 42.4 128 311 5)A A product of Idemitsu Sekiyu Kagaku Inc., average molecular weight of 1,560, hydroxyl groups content of 1.08 meg/g 6) A product of Mitsubishi Gasu Kagaku Inc.

Examples wherein the repeating unit number n of the above described hard segment is increased, are shown in the following Examples 10-12.

Test 10 This example is the repeating unit number of n = 2. A solution of 48.4 g of TDI in 145.2 g (three times as much as TDI weight) of dioxane was introduced into a reactor of 500 me. A solution of 16.6 g of 1 ,4-butanediol, 0.02 g of hydroquinone and 0.02 g of triethylenediamine in 49.8 g (three times as much as 1,4-butanediol weight) of dioxane was added thereto through a dropping funnel while stirring under an atmosphere of nitrogen.

During the addition, the reaction solution was maintained at 75-80"C and after the addition, the solution was allowed to react at 75-80"C for 2 hours. Then, a solution of 100 g of liquid rubber JSR-HTPB in 300 g (three times as much as the liquid rubber weight) of dioxane was introduced into another reactor of 1,000 me and the said reaction solution was added thereto by a dropping funnel while stirring under an atmosphere of nitrogen.

During the addition, the reaction solution was maintained at 75-80"C. After completion of the addition, the solution was allowed to react at 75-80"C for 6 hours. The disappearance of a peak of isocyanate groups was confirmed by the infrared spectrophotometer and the reaction was terminated.

The solution was purified with hexane and dried in the same manner as described in Example 1 to prepare a test piece, the cured film was determined with the physical properties and the tensile strength was 165 kg/cm2 and the elongation was 350%.

Tests 11 and 12 Then, these examples are the repeating unit numbers of n = 8 and 12 and the results are shown in Table 3.

The weight of a liquid rubber is 100 g.

TABLE 3 Example Number Dienic liquid rubber having HEMA TDI Tensile Elongation of n hydroxyl groups (g) (g) strength ( /0) Kind Weight (g) (kg/cm2) 11 8 1,4-butanediol 59.9 10.8 130.4 217 270 12 12 1,4-butanediol 89.6 10.8 188.0 267 430 Tests 13-17 An addition polymerizable monomer was added to and dissolved in the urethane acrylates obtained in Examples 1,4, and 11 and Irgacure 651 of 5% of the total weight was added thereto prepare photosensitive liquids. These photosensitive liquids were dropped on a glass plate and were spread to 100 m in thickness with the use of an applicator and exposed in the same manner as in Example 1. The tensile strength and the elongation of the cured films were determined. The results are shown in Table 4. The weight of the urethane acrylate is 100 g.

TABLE 4 Added addition Polymerizable Example Blend of urethane acrylate monomer Tensile strength Elongation NVP7) DEAMA8) (kglcm2) (o/0) (g) (g) 13 the same blend as Example 1 10 10 187 239 14 the same blend as Example 1 50 50 150 278 15 the same blend as Example 4 10 10 161 192 16 the same blend as Example 5 10 10 114 421 17 the same blend as Example 11 50 50 207 250 7) N-vinyl-2-pyrolidone is abbreviated as "NVP".

8) Diethylamino ethylmethacrylate is abbreviated as "DEAMA".

Test 18 A relief was made with using the photosensitizer blended in Example 14. The Photosensitizer blended in Example 14 was applied on a polyethylene terephthalate film on which the surface was treated with a sand setting and the surface was covered with a silicon surface treated polyethylene terephthalate film to adjust the photosensitizing layer to be 200 um thickness.

A negative film was adhered to the covered film and exposed to an ultra-high voltage mercury lamp of 3 KW placed at a distance of 30 cm from the film for 30 seconds. After the exposure, when the cover film was stripped off and a mixed solution of dioxane and ethanol (the mixed ratio was 1:2) was sprayed thereon, a non-exposed part began to dissolve easily and a relief wherein a contour of the negative film was reproduced, was obtained without swelling the exposed part.

Claims (3)

1. In a photocured composition upon the next formula of a), a photosensitive polymer of rubber which comprises bond-forming according to the following limitation of b) soft segments of a dienic liquid rubber having hydroxyl groups with hard segments of the urethane bond consisting of an ethylenically unsaturated monomer having hydroxyl groups, a dihydric alcohol of limited molecular weight of less than 2,000, and diisocyanate compound.

b) In said formula, R = an alkyl group having 1 8 carbon atoms, R, = H or CH3, R2 = a diisocyanate residue, R3 = a residue excluding hydroxyl group of dihydric alcohol, in X of a part where hydroxyl group of the dienic liquid rubber having hydroxyl groups is removed, t = 1 4, n = a length of hard segments < 16, and m is a valence of hydroxyl groups of said liquid rubber and 1 < m < 4.

2. In a photocured composition, a photosensitive polymer of rubber as in Claim 1 which comprises each limited layer of the rubber molecular chain and of the urethane bond having different cohesiveness, besides, bond-forming said two layers by a photo-crosslinked points provided to an ethylenically unsaturated monomer of said urethane bond having the value of n < =16.

3. A photosensitive polymer of rubber as in Claims 1 and 2 which can be formed in the order-free process at an optional temperature from 40"C to 80"C.