JPH0618844B2 - Liquid radiation curable resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid radiation curable resin composition, and particularly to a liquid radiation curable resin composition suitable as a hard material for coating an optical fiber.

[Conventional technology]

As a material for coating an optical fiber, various radiation-curable resin compositions containing a urethane prepolymer terminated at both ends with an ethylenically unsaturated group as a main component and containing a monomer compound and a radiation polymerization initiator are known. ing.

[Problems to be Solved by the Invention] By the way, of the optical fiber coating materials, particularly hard materials, good coatability and high curing rate, high water absorption after curing, and high hydrolysis resistance In addition, the mechanical properties are required to have performances such as high Young's modulus and large elongation, but the conventional hard materials for optical fiber coating do not have these required characteristics in a well-balanced manner. Had.

Therefore, an object of the present invention is to solve the above problems and provide a liquid radiation-curable resin composition suitable for use as a hard material for coating an optical fiber, which has these characteristics in good balance.

[Means for solving problems]

According to the present invention, in the molecule (A) the formula (I): [Wherein, n is an integer of 2 to 7], and a urethane polymer having a number average molecular weight of 800 to 2000 and having (meth) acrylate groups at at least two terminals (hereinafter, referred to as "polymer A"). A polymer having one or more structures selected from a polyalkylene ether structure and a polyalkylene carbonate structure in the molecular chain (B) and having a (meth) acrylate group at least at two terminals (provided that (Excluding the polymer of component (A)) (hereinafter referred to as “polymer B”), (C) a monomer compound containing an ethylenically unsaturated compound having a crosslinked alicyclic hydrocarbon group, and (D) a radiation polymerization initiator. A liquid radiation curable resin composition comprising is provided.

At least two of the molecular chain terminals of the polymer A which is the component (A) and the polymer B which is the component (B) of the composition of the present invention are
Although it is stopped at the (meth) acrylate group,
Examples of such molecular ends include the following formulas (II) to
The thing represented by (V) can be mentioned.

(II) CH ₂ ═C (R ₁ ) —COO—R ₂ — [In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂
Is C _{2 to} C ₈ such as ethylene group, propylene group, tetraethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, preferably C ₂
To C ₃ alkylene groups are shown. ] (III) IN FORMULA, R < ₁ > IS THE SAME AS FORMULA (II). ] (IV) IN FORMULA, R < ₁ > IS THE SAME AS FORMULA (II). ] (V) IN FORMULA, R < ₁ > IS THE SAME AS FORMULA (II). The polymer A which is the component (A) is essential to have at least one structure represented by the above formula (I). In this polymer A, in the structure (I) contained in the molecular chain, n is 2 to 7, preferably 4 to 6, and the number average molecular weight is 800 to 2000, preferably 1000 to 1300. It is necessary to be. When n exceeds 7, the cured product of the obtained composition has low Young's modulus and anti-water absorption property. The molecular weight is 80
If it is less than 0, the Young's modulus will be high, but the toughness will be poor, and if the molecular weight exceeds 2000, the balance between Young's modulus and elongation will be reduced.

In the polymer A, the structure represented by the formula (I) is bonded to at least two molecular chain end groups having the (meth) acrylate group via a urethane bond (-NHCOO-). However, other structures other than the formula (I) may be contained as long as the above-mentioned molecular weight limitation is satisfied.

Examples of such other structure include structures represented by the following formulas (VI) to (IX).

(VI) Or [In the formula, R ₃ and R ₄ are an ethylene group, a propylene group,
Tetramethylene group, pentamethylene group, _C 2 -C ₆ such as a hexamethylene group, preferably an alkylene group of _C 2 -C _4, may be the same or different, l and m are each 0 to 50, It is preferably an integer of 5 to 20 and must not be 0 at the same time, and n is an integer of 0 to 50, preferably 1 to 10. ] (VII) Or [In formula, R < ₃ > is the same as Formula (VI), R < ₆ >, R <7>,
R ₈ and R ₉ are a hydrogen atom or a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group,
C ₁ -C ₈ alkyl group such as heptyl group, octyl group, phenyl group, cyclohexyl group, aryl group or cycloalkyl group, preferably C ₁ -C ₃ alkyl group, which may be the same or different Also, r and s are integers of 1 to 50, preferably 5 to 20, and q is an integer of 1 to 20, preferably 5 to 20. ] (VIII) [In the formula, R ₃ and R ₄ are the same as those in the formula (VI), and R ₅
Is the structural formula: Represents a C ₂ -C ₈ divalent aliphatic, alicyclic or aromatic hydrocarbon group, wherein l and m are the same as in formula (VI), p is 1 to 50, preferably It is an integer of 1 to 20. ] (IX) -R ₁₀ - wherein, R ₁₀ is an ethylene group, a propylene group, tetramethylene group, hexamethylene group, cyclohexylene group, methylene bis-cyclohexylene group, p- phenylene, methylene-bis-phenylene group or Structural formula: Divalent aliphatic C ₂ -C ₂₀ represented by like, an alicyclic or aromatic hydrocarbon group. The polymer A as the component (A) may contain a structure other than the formula (I) as described above, but the proportion of the structure of the formula (I) is 30% by weight or more, particularly 40% by weight or more of the polymer. Is preferred. When the structure of the formula (I) is less than 30% by weight, the Young's modulus of the resulting composition after curing may be lowered.

Next, a method for producing the polymer A will be illustrated.

[Production Method 1] An acrylic system having a hydroxyl group in the isocyanate group of a polymer having two isocyanate groups and obtained by reacting a diol having the structure of formula (I) with a diisocyanate compound Alternatively, a method of introducing a (meth) acrylate group via a urethane bond by reacting a methacrylic compound.

[Production Method 2] The isocyanate group of a polymer having an isocyanate group obtained by reacting a diisocyanate compound with an acrylic or methacrylic compound having a hydroxyl group and a (meth) acrylate group, and having an isocyanate group of a polymer bonded by a urethane bond, the formula A method of binding via a urethane bond by reacting a diol having the structure of (I).

In the above method, as the starting compound, the following compounds can be mentioned.

Examples of the diol having the structure of formula (I) include polycaprolactone diol represented by the following formula.

IN FORMULA, N IS THE SAME AS FORMULA (I). ] As the diisocyanate compound, 2,4-triene diisocyanate, 2,6-toluene diisocyanate,
1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4 ' -Diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, methylenebis (4-cyclohexyl isocyanate) and the like.

Examples of the acrylic or methacrylic compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyoctyl (meth) acrylate, pentaerythritol tri (meth) acrylate, and glycerin. Examples include di (meth) acrylate and dipentaerythritol monohydroxypenta (meth) acrylate.

Next, a preferred embodiment of the above production method 1 will be shown.

The amount of the diisocyanate compound used is about 1 mol per equivalent of the hydroxyl group of the diol having the structure of formula (I).
In this reaction, a catalyst such as copper naphthenate, cobalt naphthenate, zinc naphthenate, n-butyltin laurate, and triethylamine is usually used in an amount of 0.01 to 1.0 parts by weight based on 100 parts by weight of the total amount of the reactants. . The reaction temperature in this reaction is 30 to 80 ° C.

The isocyanate group of the intermediate product thus obtained is reacted with an acrylic or methacrylic compound having a hydroxyl group, and the amount of the acrylic or methacrylic compound having a hydroxyl group is the isocyanate of the intermediate product. It is about 1 mol per 1 equivalent of the group, and the reaction conditions are the same as the reaction conditions for producing the intermediate product.

Next, a preferred embodiment of the above production method 2 will be shown.

About 1 mol of an acrylic or methacrylic compound having a hydroxyl group is reacted with 1 mol of a diisocyanate compound under the same reaction conditions as in the production method 1. With respect to 1 equivalent of the isocyanate group of the resulting intermediate product, the diol having the structure of the formula (I) or, in some cases, the diol and the diamine are adjusted so that the total amount of the hydroxyl group or the hydroxyl group and the amino group is about 1 equivalent. And the reaction is performed under the same reaction conditions as the reaction between the diol and the diisocyanate compound in the production method 1.

The polymer B, which is the component (B) of the composition of the present invention, has at least one of a polyalkylene ether structure and a polyalkylene carbonate structure in the molecular chain. Examples of the polyalkylene ether structure here include the structure of the above formula (VI), and examples of the polyalkylene carbonate structure include the structure of the above formula (VII).

Of course, the polymer B may have a structure other than the polyalkylene ether structure and the polyalkylene carbonate structure, and as an example of such a structure, the above formula (I
The structure represented by X) and the structures represented by the following formulas (X) to (XII) may be mentioned. These structures and the (meth) acrylate group at the molecular end are urethanes as described for the polymer A. Although it is bonded via a bond, it may be bonded via a urea bond (-NH-CO-NH-) in some cases.

(X) [In the formula, R ₁₁ represents a C _{1 to} C ₈ alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a phenyl group, a cyclohexyl group, or an aryl group. Or a cycloalkyl group, preferably a C ₁ -C ₃ alkyl group, wherein R ₁₂ has the formula: An alkylene group represented by (wherein R ₁₃ and R ₁₄ are a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group,
Pentyl group, a hexyl group, a heptyl group, an octyl group, a phenyl group, an alkyl group of C ₁ -C _8, such as a cyclohexyl group, an aryl group or a cycloalkyl group, preferably represents a hydrogen atom or an alkyl group with C ₁ -C ₃ , W may be the same or different, and w is an integer of 1 to 20, preferably 1 to 6), a phenylene group, a cyclohexylene group, a methylenebiscyclohexylene group, or a p-phenylene group. And x is an integer of 1 to 1000, preferably 20 to 100. ] (XI) [Wherein, R ₁₁ and R ₁₂ are the same as those in formula (X), y is an integer of 1 to 1000, preferably 30 to 130, and z is an integer of 1 to 10, preferably 2 to 5. . ] (XII) [In the formula, t / (t + u) is 0.2 to 0.8, and v is 5 to
It represents an integer of 200, and any double bond in the formula may be cleaved by hydrogenation. The number average molecular weight of the polymer B as the component (B) is preferably 1000 to 3000, particularly preferably 1400 to 2400. By combining the polymer B with the polymer A as the component (A), it is possible to obtain a high elongation while maintaining a high Young's modulus after curing of the composition. However, if the molecular weight of the polymer B is less than 1000, the elongation may be low, and if it exceeds 3000, the balance between the Young's modulus and the elongation may be deteriorated.

Polymer B is 25 with
It is preferably used in an amount of from 400 to 400 parts by weight, particularly from 30 to 300 parts by weight.

Examples of the method for producing the polymer B include the following.

[Production method i]

An acrylic system having a hydroxyl group in the isocyanate group of a polymer having two isocyanate groups and bonded by a urethane bond, which is obtained by reacting one or more kinds of diols selected from polyether diols and polycarbonate diols with a diisocyanate compound. Alternatively, a method of introducing a (meth) acrylate group through a urethane bond by reacting a methacrylic compound.

[Production method ii]

Polyether diol, polycarbonate diol, obtained by reacting a diisocyanate compound with an acrylic or methacrylic compound having a hydroxyl group, the isocyanate group of a polymer having an isocyanate group and a (meth) acrylate group and bonded by a urethane bond. A method of reacting one or more diols selected from the above, or in some cases, a combination of diamines with the diols to bond them through a urethane bond and optionally a urea bond.

[Production method iii]

One or more diols selected from polyether diols and polycarbonate diols, or optionally a combination of the diols and diamines, is reacted with a diisocyanate compound and has two isocyanate groups, a urethane bond and, in some cases, Furthermore, a method of introducing a (meth) acrylate group through a urethane bond by reacting an acrylic or methacrylic compound having a hydroxyl group with an isocyanate group of a polymer bonded by a urea bond.

In the above production methods i to iii, the following compounds can be exemplified as the compounds used as the starting compounds.

Examples of the polyether diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like, and liquid polybutadiene having two hydroxyl groups in one molecule or a hydrogenated product of this compound.

Examples of the polycarbonate diol include polyethylene carbonate diol, polypropylene carbonate diol, and polytetramethylene carbonate diol.

Examples of the diamine optionally used in combination with the diol include, for example, ethylenediamine, tetramethylenediamine, hexamethylenediamine, p-phenylenediamine, 4,4′-diaminediphenylmethane and the like; diamines containing a hetero atom; polyether diamine. Etc.

Next, a preferred embodiment of the above production method i will be described.

Polymer B is produced under the same conditions as in Production Method 1, except that one or more diols selected from the above-mentioned polyether diol and polycarbonate diol are used instead of the diol used in Production Method 1 which is a production method of Polymer A. Method.

Next, a preferred embodiment of the above production method ii will be described.

About 1 mol of an acrylic or methacrylic compound having a hydroxyl group per 1 mol of a diisocyanate compound
React under the same reaction conditions as in. The amount of hydroxyl groups or hydroxyl groups or hydroxyl groups present in one or more diols selected from the above-mentioned polyether diols and polycarbonate diols or a combination of these diols and diamines, relative to 1 equivalent of isocyanate groups of the resulting intermediate product. Are used so that the total amount of the combined amine groups is about 1 equivalent, and the reaction is carried out under the same conditions as in the reaction of the diol and the diisocyanate compound in the above Production Method 1.

Next, a preferred embodiment of the above production method iii will be shown.

The amount of hydroxyl groups in one or more diols selected from the above-mentioned polyether diols and polycarbonate diols or a combination of the diols with at least one diamine, or the total amount of hydroxyl groups or amino groups optionally present in the hydroxyl groups is 1 equivalent. Approximately 1 mol of the diisocyanate compound is used, and the reaction is carried out in the same manner as in Production method 1. The resulting isocyanate group of the intermediate product is reacted with an acrylic or methacrylic compound having a hydroxyl group. The amount of the acrylic or methacrylic compound having a hydroxyl group is the isocyanate group 1 of the intermediate product.
It is about 1 mol per equivalent, and the reaction conditions are as follows:
Is the same as.

In carrying out the above-mentioned production methods 1-2 and production methods i-iii,
A polyol other than difunctional with a diol, a polyamine other than difunctional with a diamine, and a polyisocyanate other than difunctional with a diisocyanate compound can be used together to the extent that the product does not gel,
Usually, the combined amount is 5 to 30 parts by weight based on 100 parts by weight of the diol, diamine or diisocyanate compound. Examples of the non-bifunctional polyol here include, for example, an adduct of glycerin and propylene oxide, glycerin, 1,2,3-pentanetriol, 1,2,3.
-Butanetriol, tri (2-hydroxypolyoxypropyl) polysiloxane, polycaprolactone triol, polycaprolactone tetraol, 2 per molecule
Liquid polybutadiene having more than one hydroxyl group or a hydrogenated product of this compound may be mentioned. Examples of non-bifunctional polyamines include diethylenetriamine, 1,2,3-triaminopropane, and polyoxypropyleneamine. Examples of non-bifunctional polyisocyanates include polymethylene polyphenyl isocyanate and triphenyl. Methane-4,4 ',
4 ″ -triisocyanate and the like can be mentioned.

The monomer compound which is the component (C) used in the composition of the present invention includes an ethylenically unsaturated compound having a crosslinked alicyclic hydrocarbon group (hereinafter, abbreviated as "crosslinked ethylenically unsaturated compound"). Be done.

Specific examples of the crosslinked alicyclic hydrocarbon group include an isobornyl group, a dicyclopentenyl group, a bornyl group and the like. Examples of the cross-linked ethylenically unsaturated compound include acrylates, diacrylates, methacrylates, dimethacrylates, oxyethyl acrylates, and oxyethyl methacrylates of these cross-linked alicyclic hydrocarbon groups. Nyl acrylate, isobornyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, bornyl acrylate, bornyl methacrylate,
Examples thereof include isobornyloxyethyl acrylate, isobornyloxyethyl methacrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyl diacrylate, and dicyclopentenyloxydiacrylate. Among these, preferred crosslinked ethylenically unsaturated compounds include isobornyl acrylate, isobornyl methacrylate, dicyclopentenyl acrylate, and dicyclopentenyl methacrylate.

The monomer compound as the component (C) is, in addition to the above-mentioned crosslinked ethylenically unsaturated compound, other monomer compounds, if necessary, within a range that does not adversely affect the curing rate of the composition, the mechanical properties after curing, and the like. Can be used together. The other monomer compound that can be used in combination is a compound that has good compatibility with the crosslinked ethylenically unsaturated compound and has an ethylenically unsaturated group, and controls the viscosity of the composition of the present invention and the mechanical properties of the cured product. can do. As such other monomer compound, both a monofunctional compound and a polyfunctional compound are used. When a cured product having a relatively low elastic modulus is desired, a monofunctional compound is mainly used, but the elastic modulus of the cured product can be adjusted by using a polyfunctional compound in an appropriate ratio. Although these monofunctional compounds and polyfunctional compounds are not limited to these, the following can be mentioned as typical examples.

Monofunctional compound; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, butoxyethyl acrylate, ethyldiethylene glycol acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenoxyethyl acrylate, dicyclopentadiene acrylate, polyethylene glycol acrylate Acrylic compounds such as polypropylene glycol acrylate, methyltriethylene glycol acrylate, diethylaminoethyl acrylate, 7-amino-3,7-dimethyloctyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, polypropylene glycol methacrylate, diethyl Methacrylic compounds such as aminoethyl methacrylate, vinyl pyrrolidone, vinyl phenol, acrylamide, vinyl acetate, vinyl ethers, styrene.

Polyfunctional compounds; trimethylolpropane triacrylate, ethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, polyester diacrylate, diallyl Adipate, diallyl phthalate, triallyl isocyanurate, bisphenol A glycidyl ether adduct at both ends.

Among these, preferred are acrylates whose functional group is an acryloyl group, from the viewpoint of curing speed and compatibility.

The proportion of the crosslinked ethylenically unsaturated compound in the monomer compound as the component (C) is preferably 2% by weight or more, and particularly preferably 10% by weight or more. If this proportion is less than 2% by weight, the composition will have a poor balance of curing rate, mechanical properties after curing, anti-water absorption and the like.

Further, the total amount of all the monomer compounds as the component (C) used is preferably 20 to 80% by weight, and particularly preferably 30 to 60% by weight, based on the composition of the present invention.

As the radiation polymerization initiator which is the component (D), various ones known per se can be used, but specific examples include 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone, Fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,
4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, acetophenone diethyl ketal, benzoin ethyl ether, benzyl dimethyl ketal, 1-
(4-Isopropylphenyl) -2-hydroxy-2-
Methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one and the like can be mentioned, and these can be used alone or in combination of two or more. Further, if necessary, a sensitizer such as an amine compound (radiation polymerization accelerator) can be used together.

In the present invention, the amount of the radiation polymerization initiator as the component (D) used is usually 0.1 to 5% by weight, preferably 1 to 3% by weight.

The viscosity of the composition of the present invention prepared by uniformly mixing the above-mentioned components is usually 1,000 to 20,000 cp / 25 ° C, preferably 2,
It is 000 to 10,000 cp / 25 ° C.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples.
The present invention is not limited to these examples.

Example 1 (1) A reactor equipped with a stirrer was charged with 524 g of 4,4′-methylenebis (cyclohexyl isocyanate), 2 g of dibutyltin dilaurate and 1 g of 2,6-ditbutyl-4-methylphenol. In addition to this, polycaprolactone diol (Placcel 205A, manufactured by Daicel Chemical Industries, Ltd.)
L, number average molecular weight: 500) (500 g) was added over 3 hours while controlling the internal temperature to 60 to 70 ° C. After the addition was completed, stirring was continued at 60 to 70 ° C for about 1 hour. Thereafter, 232 g of 2-hydroxyethyl acrylate was added over 1 hour while keeping the internal temperature at 60 to 70 ° C. The obtained liquid polymer is referred to as polymer a.

(2) Instead of 500 g of the polycaprolactone diol,
A polymer was produced in the same manner as in (1) except that 650 g of polytetramethylene glycol having a molecular weight of 650 (Teracor 650 manufactured by DuPont) was used. Hereinafter this polymer is referred to as polymer b.

(3) To 100 parts by weight of the polymer a, 300 parts by weight of the polymer b was added so that the total amount would be 1000 g, and further 533 g of isobornyl acrylate, 107 g of vinylpyrrolidone,
27 g of trimethylolpropane triacrylate, 36 g of acetophenone diethyl ketal and 18 of benzophenone
g was mixed to obtain a radiation curable liquid resin composition.

Example 2 (1) A reactor equipped with a stirrer was charged with 348 g of 2,4-toluene diisocyanate, 2 g of dibutyltin dilaurate and 1 g of 2,6-ditbutyl-4-methylphenol. 2-hydroxyethyl acrylate 232g
Was added while controlling the internal temperature to 50 to 60 ° C. Then, 850 g of polycaprolactone diol having a molecular weight of 850 (Placcel 805AL, manufactured by Daicel Chemical Industries, Ltd.) was added over 3 hours while controlling the internal temperature to 60 to 70 ° C. After the addition yield, stirring was continued at 60 to 70 ° C. for about 1 hour. The obtained liquid polymer is referred to as polymer c.

(2) Same as Example 1- (3) except that 100 parts by weight of the polymer c was added to the polymer b obtained in Example 1- (2) in a proportion of 100 parts by weight so that the total amount was 1000 g. Thus, a radiation curable liquid resin composition was obtained.

Example 3 (1) In Example 1- (2), a polycarbonate diol having a number average molecular weight of 1000 (DN-981 manufactured by Nippon Polyurethane Industry Co., Ltd.) was used instead of polytetramethylene glycol.
A polymer was produced in the same manner as in Example 1- (2) except that 1250 g was used. The polymer obtained is called polymer d.

(2) 100 parts by weight of the polymer a obtained in Example 1- (1) was mixed with 35 parts by weight of the polymer d in a total amount of 1000 g, and dicyclopentenyl acrylate 533 was added.
g, vinylpyrrolidone 107 g, trimethylolpropane triacrylate 27 g, acetophenone diethyl ketal 36 g, benzophenone 18 g and diethylamine 17 g
To obtain a radiation curable liquid resin composition.

Comparative Example 1 A composition was prepared in the same manner as in Example 1- (3), except that only 1000 g of the polymer b was used instead of using the two types of polymers a and b in Example 1- (3).

Test Example Using the compositions obtained in the above Examples and Comparative Examples, test pieces were prepared as described below, and the following tests were conducted.

1. Preparation of test piece A glass plate was coated with the composition using an applicator having a thickness of 250 μm and irradiated with 1 J / cm ² (wavelength 350 nm) of ultraviolet rays to obtain a cured film. The cured film was peeled from the glass plate and conditioned for 24 hours at 23 ° C. and 50% relative humidity to prepare a test piece.

2. Measurement of Water Absorption Rate Using the above test piece, the water absorption rate was measured according to JIS K7301. The results are shown in Table-1.

3. Curing speed measurement Ultraviolet irradiation device (3.5KW output) manufactured by Oak Manufacturing Co., Ltd.
Using an optical fiber drawing apparatus equipped with, the optical fiber is drawn and coated with the composition at a drawing speed of 1 m / sec and 3 m / sec,
Cured.

The composition-coated and cured fiber was folded into a suitable length and subjected to Soxhlet extraction (methyl ethyl ketone, 12
Time), and obtain the extraction residual rate from the weight before and after extraction, 1
The extraction residual rate at a drawing speed of 3 m / sec was calculated with the extraction residual rate at a drawing speed of m / sec being 100, and the curing rate was evaluated. The results are shown in Table-1.

4. Tensile test A strip of test piece with a width of 6mm was cut out from the cured film, and after adjusting the same conditions, the distance between the marked lines was set to 25mm. The crosshead was 1mm / mm for Young's modulus measurement and the crosshead speed was 50mm for elongation measurement. Young's modulus and elongation were measured under the condition of / mm. The results are shown in Table-1.

[Effect of the invention] The liquid radiation-curable resin composition of the present invention has excellent coatability and is rapidly cured by irradiation with various radiations such as X-rays, electron beams, ultraviolet rays, and visible light.
A cured product having high water absorption and hydrolysis resistance, a high Young's modulus, and a large elongation is formed. Therefore, this composition is particularly excellent as a hard material for coating an optical fiber and also as a coating material for various other substrates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Otaka 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Inventor Kazuo Fuse 2-11-24 Tsukiji, Chuo-ku, Tokyo No. Japan Synthetic Rubber Co., Ltd. (72) Inventor TE Ebisuyopu Argon Quinn Riverwood Drive, Illinois, USA 1720 (56) References JP-A-61-207478 (JP, A)

Claims (1)

[Claims] 1. A formula in the molecule (A): [Wherein, n is an integer of 2 to 7], and a urethane polymer having a number average molecular weight of 800 to 2000, having a (meth) acrylate group at least at two terminals, (B) molecule A polymer having at least one structure selected from a polyalkylene ether structure and a polyalkylene carbonate structure in the chain and having (meth) acrylate groups at least at two terminals (however, the polymer of the component (A) is excluded) ), A liquid radiation curable resin composition comprising (C) a monomer compound containing an ethylenically unsaturated compound having a cross-linked alicyclic hydrocarbon group, and (D) a radiation polymerization initiator.