JPH0468010A - Ultraviolet-curable composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which is excellent in optical properties and the properties of a cured product and can easily form an optical molding by mixing a specified unrethane (meth)acrylate with a (meth)acrylate and a photopolymerization initiator in a specified ratio. CONSTITUTION:An ultraviolet-curable composition for molding an optical component comprising 100pts.wt. urethane (meth)acrylate (A) prepared from a polyol, a polyisocyanate and an active hydrogen-containing (meth)acrylate, wherein the polyol is present in the molecule in the form of a structural formula I (wherein (m) is 5-100), 50-200pts.wt. (meth)acrylate (B) of formula II (wherein R1 is H or CH3; R2 is H or 20 C or lower alkyl; A is an ethylene or propylene group; and (n) is 1-20) and 0.01-2.5pts.wt., per 100pts.wt. total of components A and B, photopolymerization initiator and having a viscosity of 300-3,000cp. This composition can easily form an optical component such as a Fresnel lens and is excellent in chemical resistance, heat resistance, cold resistance and toughness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultraviolet curable composition suitable for manufacturing optical components such as Fresnel lenses.

[Prior Art] It is known that ultraviolet curing resin is used to manufacture optical parts such as Fresnel lenses (Japanese Patent Laid-Open No. 16333/1983).
Publication No. 0). Furthermore, urethane acrylate using polytetramethylene glycol as one of the polyol components is known as a coating material for optical transmission glass fibers (Japanese Patent Application Laid-Open No. 642481).

[Problems to be Solved by the Invention] However, conventional products cannot meet all of the optical properties required for optical components and the physical properties of cured products such as toughness, chemical resistance, heat resistance, cold resistance, and moisture resistance. was not satisfactory. Furthermore, although the composition described in JP-A-64-2481 is useful as a coating material for glass fibers, it has a high viscosity and is unsuitable for molding optical parts.

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of studying ultraviolet curable compositions that have excellent optical properties and physical properties of cured products and are easy to mold into optical parts.

That is, the present invention provides a urethane (meth)acrylate made from a polyol (a), a polyisocyanate (b), and an active hydrogen-containing (meth)acrylate (c), wherein the polyol (a) is present in the molecule with -(○CH ,CH
Urethane (meth)acrylate having the structure 2CH2CH, ), - (where m is 5 to 100) [
A], general formula % formula % (1) (wherein, R3 is a hydrogen atom or a methyl group, R2 is a hydrogen atom or an alkyl group having 20 or less carbon atoms, A is an ethylene group or a propylene group, and n is a 1-20 The (meth)acrylate [B] and photopolymerization initiator [C] represented by (an integer) are essential components [based on 1100 parts by weight of
[B] is 50 to 200 parts by weight, [C] is 0.01 to 2.5 parts by weight with respect to a total of 100 parts by weight of [A] and [B], and the viscosity is 300 to 3000 cps. This is an ultraviolet curable composition for cast molding of optical parts.

In addition, the viscosity in the present invention was measured at 25°C using a B-type viscometer.
It was measured at

Furthermore, (meth)acrylate in the present invention refers to acrylate and/or methacrylate (the same applies below).

The polyol (a) in the present invention has (○CH
2CH, CH2CH2), - has the structure. m is 5~
100, preferably 10-50. If m is less than 5, the obtained cured product will have poor toughness, and if it exceeds 100, the viscosity of the composition will be high, making it difficult to cast when producing optical parts.

Examples of (a) include polytetramethylene glycol,
Alkylene oxides of polytetramethylene glycol [alkylene oxides having 2 to 4 carbon atoms, such as ethylene oxide (hereinafter abbreviated as EO under JJ), propylene oxide (hereinafter abbreviated as PO), and butylene oxide] and/or lactones (carbon atoms (usually 3 to 7) adducts, and ring-opening polymerization of tetrahydrofuran to polyalkylene polyols (polyethylene glycol, polypropylene glycol, etc.).

The molecular weight of (a) is usually 500 to 10,000, preferably 600 to 5,000. (a) In -(OC
The portion represented by the structure H2CH2CH2CH, ), - accounts for 50% or more, preferably 60% or more of [a] on a weight basis.

Note that if the polyol (a) according to the present invention is used together with a low molecular weight polyol such as ethylene glycol, 1,4-butanediol, or 16-hexanediol, the viscosity of the composition will become too high, making it difficult to mold optical parts. is not suitable.

Known polyisocyanates can be used as the polyisocyanate (b), including aliphatic polyisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate, and aromatic polyisocyanates such as tolylene diisocyanate and dimethyldiphenylmethane diisocyanate. Preferred are isophorone diisocyanate and dicyclohexylmethane diisocyanate.

As the active hydrogen-containing (meth)acrylate (c), hydroxyalkyl (the number of carbon atoms in the alkyl group is usually 2 to
4) (Meth)acrylate [Hydroxyethyl (
meth)acrylate, hydroxypropyl (meth)acrylate, etc.], alkylene oxide (alkylene oxide having 2 to 4 carbon atoms, such as EO, PO and butylene oxide) adducts (hereinafter abbreviated as AOA) of hydroxyalkyl (meth)acrylate; /or adducts of lactones (usually 3 to 7 carbon atoms) (the number of moles added is usually 1 to 20, preferably 1 to 10); and the like.

Urethane (meth)acrylate [A] from (a), (b) and (c) is obtained by reacting (a), (b) and (c). (a),
When reacting (b) and (c), usually (a)
For 1 mole (b) is 1.5 to 2 moles (c) is 1 to 2
molar used.

The reaction method includes a method in which (a), (b) and (c) are collectively charged into a reaction vessel and reacted;
(b) 'J6 and (c) are divided and reacted in multiple stages [For example, after reacting (a) and (b), (
c)).

The reaction temperature is usually 40-130°C, preferably 60-130°C.
The temperature is 20°C. In the reaction, catalysts used in ordinary urethane reactions (dibutyltin dilaurate, stannath octoate, etc.) can also be used to promote the reaction.

[The molecular weight of A is usually 600 to 12,000, preferably 1,000 to 6,000.

The (meth)acrylate [B] in the present invention is represented by the general formula (1), and R1 is a hydrogen atom or a methyl group. R2 is a hydrogen atom or an alkyl group having 20 or less carbon atoms, preferably 5 to 15 carbon atoms. A is an ethylene group or a propylene group, and n is 1 to 20, preferably 2 to 10. If n is less than 1, the toughness of the cured product will be poor, and if it exceeds 20, the refractive index of the cured product will be low.

In the composition of the present invention, [B] and known monofunctional, trifunctional, and polyfunctional (meth)acrylates may be used in combination, if necessary. The (meth)acrylate used in combination is not particularly limited, but examples of monofunctional (meth)acrylates include AO such as 2-ethylhexyl (meth)acrylate, 2-ethylhexanol, and phenol.
Examples include A (meth)acrylate. Also,
Trifunctional (meth)acrylates include glycols such as 1,4-butylene glycol, neopentyl glycol, and 1.6 hexane glycol, and bisphenol A1.
Examples include bisphenols such as bisphenol F, and trifunctional (meth)acrylates of these AOAs. Polyfunctional (meth)acrylates include polyhydric alcohols such as trimethylolpropane, pentaerythritol, dipentaerythritol, and these A
Examples include polyfunctional (meth)acrylate of OA. When using trifunctional (meth)acrylate together, [B
] 30B or less per 100 parts by weight, polyfunctional (meta)
When acrylate is used in combination, the amount is preferably 5 parts or less.

In addition, radically polymerizable polymers other than (meth)acrylate (for example, vinyl group- or allyl group-containing monomers) can be used in combination.

Examples of the photopolymerization initiator [C] in the present invention include benzoin alkyl ether, benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-
Hydroxy-2-methyl 1-phenylpropan-1-one, benzophenone, methyl benzoyl formate,
Examples include isopropylthioxanthone.

The weight ratio of [A, [B] and [C] is [Al2O
[B] is 50 to 200 parts per 2 parts, preferably 60 parts
~150 parts, and [C] is 0.01 to 2.5 parts, preferably 0.01 to 2.5 parts, with respect to 100 parts in total of [A] and [B].
05-2 parts.

When [B] is less than 50 parts, the viscosity of the composition becomes high,
It becomes difficult to mold optical parts. Moreover, if it exceeds 200 parts, the toughness of the cured product decreases. When [C] is less than 0.01 part, the curing time becomes long, and even if it is used in excess of 2.5 parts, the curing time is hardly shortened.

In addition, additives such as a thermal polymerization inhibitor, an antifoaming agent, a leveling agent, a coupling agent, etc. can be added to the composition of the present invention if necessary.

The composition of the present invention can be cured by irradiating it with ultraviolet light. There are no particular limitations on the ultraviolet irradiation device.
Any known material can be used.

[Example] The present invention will be explained below using Examples, but the present invention is not limited thereto. Parts in Examples indicate parts by weight.

Synthesis Example 1 Molecule! 2000 polytetramethylene glycol 20
0 parts, 44.4 parts of isophorone diisocyanate) and 0.0 parts of dibutyltin dilaurate were taken, and 90 to 100 parts of
℃ for 3 hours, then 2 parts of 23° hydroxyethyl acrylate and 0.2 parts of monoethylhydroquinone
The mixture was reacted at 85 to 95°C for 7 hours to obtain urethane acrylate rU-IJ.

Synthesis Example 2 Similarly to Synthesis Example 1, glycol obtained by adding P○ to polytetramethylene glycol with a molecular weight of 600 (molecule ji100
0) 100 parts, dicyclohexylmethane diisocyanate) 52.4 parts and dibutyltin dilaurate 0.00
5 parts were reacted at 90 to 100°C for 3 hours, then 23.2 parts of hydroxyethyl acrylate and 0.1 part of monomethylhydroquinone were added, and the mixture was reacted at 85 to 95°C for 7 hours to form urethane acrylate) rU-2J. Obtained.

Synthesis Example 3 Same as Synthesis Example 1, polytetramethylene glycol 100fi with a molecular weight of 1000, 44.4 parts of isophorone diisocyanate, and dibutyltin dilaure) 0.005
8 was reacted at 90 to 100°C for 3 hours, and then 23.2 parts of hydroxyethyl acrylate and 0.1 part of monomethylhydroquinone were added, and the mixture was reacted at 85 to 95°C for 7 hours to obtain urethane acrylate rU-3J.

Synthesis Example 4 As in Synthesis Example 1, 200 parts of polypropylene glycol with a molecular weight of 2000 and 44 parts of isophorone diisocyanate were added.
4 parts and 0.005 parts of dibutyl tin dilaure) to 9 parts
The mixture was reacted at 0 to 100°C for 3 hours, and then 232 parts of hydroxyethyl acrylate and 0.1 part of monomethylhydroquinone were added, and the mixture was reacted at 85 to 95°C for 7 hours to obtain urethane acrylate rU-4.

Synthesis Example 5 As in Synthesis Example 1, 100 parts of polytetraethylene glycol with a molecular weight of 2000, 4.5 parts of 1,4-butanediol
33.3 parts of isophorone diisocyanate and 0.005 parts of dibutyltin dilaurate at 90-100°C.
react for an hour, then hydroxyethyl acrylate) 1
1.6 parts and 0.1 part of monomethylhydroquinone were added, and the mixture was reacted at 85 to 95°C for 7 hours to obtain urethane acrylate rU-5J.

Example 1 Urethane acrylate rU-IJ 50 parts Monomer A [general formula (■) in which R1 is a hydrogen atom, R2 is a nonyl group, and n is 2] 40 parts Diacrylate of 2 moles of EO adduct of bisphenol A 10 parts 1- Contains 1 part of hydroxycyclohexylphenyl ketone,
The composition of the present invention was uniformly dissolved and had a viscosity of 1650 cps.

Example 2 Urethane acrylate "U-2J" 50 parts Monomer B [Formula (1) where R is a hydrogen atom, R2 is a nonyl group, and n is 4] 40 parts Diacrylate of 2 moles of EO adduct of bisphenol A 10 parts A composition of the present invention having a viscosity of 1050 cps was obtained using 1 part of 1-hydroxycyclohexyl phenyl ketone in the same manner as in Example].

Example 3 Urethane acrylate ~) rU-3J 5 parts Monomer C [general formula (I) where R R2 is a hydrogen atom and n is 2] 40 parts Diacrylate of E0 2 mole adduct of bisphenol A 10 parts 1 - Hydroxycyclohexylphenyl ketone 1 part was treated in the same manner as in Example 1 to obtain a composition of the present invention having a viscosity of 2050 cps.

Comparative Example 1 A viscosity of 900c was obtained in the same manner as in Example 1 using rU-4J instead of the urethane acrylate rU-IJ in Example 1.
A composition for comparison of ps was obtained.

Comparative Example 2 The urethane acrylate rU-IJ of Example 1 was replaced with rU-5J, and the viscosity was 4100 in the same manner as in Example 1.
A comparative composition of cps was obtained.

Test Example 1 30cm x 3 1-shaped groove cut concentrically
The compositions obtained in Examples 1 to 3 and Comparative Example 1 were applied to a Q cm resin mold to a thickness of 1 mm, covered with a polyester film, and exposed to ultraviolet rays at 100 mJ/cm from the polyester film surface. A Fresnel lens was produced by irradiating cm2.

The test results for chemical resistance are shown in Table 1, and the test results for toughness, heat resistance, and cold resistance are shown in Table 2.

Test Example 2 A Fresnel lens was prepared using the composition obtained in Comparative Example 2 in the same manner as in Test Example 1, but this lens had air bubbles and the transferability of the single-shaped groove was insufficient.

Table (Note 1) Acid resistance: After soaking in 1% sulfuric acid aqueous solution for 24 hours, washing with water and drying, check the appearance.

Alkali resistance: 24% in 1% sodium hydroxide aqueous solution
After soaking for an hour, wash and dry and check the appearance.

impregnated with 0% methanol Test by applying a load of 500g to the open air Go back and forth on one side 10 times.

Enduring Luko Table-2 (Note 2) Toughness: Check for scratches by rubbing with your fingernail.

Heat resistance: Check the appearance after leaving at 40℃ for 168 hours.

Cold resistance: Check the appearance after leaving at -20℃ for 168 hours.

[Effects of the Invention] The composition of the present invention can be easily molded into optical components such as Fresnel lenses, and has excellent chemical resistance, toughness, heat resistance, and cold resistance.

Patent applicant: Sony Corporation (Note 2)

Claims (1)

[Scope of Claims] 1. A urethane (meth)acrylate from polyol (a), polyisocyanate (b) and active hydrogen-containing (meth)acrylate (c), which comprises polyol (a)
is in the molecule -(OCH_2CH_2CH_2CH_2)
Urethane (meth)acrylate [A] having the structure __m- (where m is 5 to 100), general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, R_1 is a hydrogen atom or methyl group, R_2 is a hydrogen atom or an alkyl group having 20 or less carbon atoms, A is an ethylene group or a propylene group, n is an integer from 1 to 20)
(meth)acrylate [B] and photopolymerization initiator [C] shown as essential components, [B] is 50 to 200 parts by weight per 100 parts by weight of [A], [A] and [B]
[C] is 0.01 to 2.5 per 100 parts by weight of
An ultraviolet curable composition for molding optical parts having a viscosity of 300 to 3000 cps.