JP2003048922A - Active energy ray-curable resin sheet formation agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray-curable resin sheet formation agent giving resin sheets which have excellent heat resistance, excellent transparency and low water absorption, are free from a problem of coloration, further have excellent solvent resistance, and are especially suitable for photoelectronic elements. SOLUTION: This active energy ray-curable resin sheet formation agent comprises a di(meth)acrylate represented by the general formula (1) [R<1> is an alkylene; R<2> is H or methyl; (a) and (b) are each independently an integer of 1 to 5].

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an active energy ray-curable resin sheet forming agent, and the resin sheet obtained by the present invention can be used in various applications such as optical lenses and various laminated sheet members. In particular, it can be suitably used for an optical resin sheet applied to optoelectronics.

[0002]

2. Description of the Related Art Conventionally, optoelectronic devices used for various purposes have been manufactured by forming devices on a glass substrate having a transparent conductive layer. However, with the recent rapid progress in electronics technology, portable devices such as mobile phones and notebook computers have become widespread, and it seems to be advantageous to carry even for a display unit using an optoelectronic element. Moreover, there is a growing demand for weight reduction and improved impact resistance. Therefore, in these display parts, "fragile" that the conventional glass substrate has,
The drawback of "large specific gravity" has become a problem, and it has been studied to use a resin sheet as a substrate material instead of the conventional glass substrate.

By the way, in the process of forming an optoelectronic element, heat resistance of at least 150 ° C. or higher is required. Polyimide resins, phenol resins, epoxy resins, and the like are widely known as heat-resistant polymers, but these resins have problems in transparency and the like and cannot be used for the above applications.

[0004]

On the other hand, a cured product obtained by radically polymerizing a composition comprising a polyfunctional (meth) acrylate such as di (meth) acrylate by heat or light is the above heat-resistant resin. Is more transparent than
Furthermore, it is excellent in solvent resistance and is being studied as a resin sheet for optoelectronic devices. However, in the case of a composition comprising a conventional polyfunctional (meth) acrylate, when the composition is an active energy ray-curable composition, the cured product is colored during photocuring in the presence of oxygen or in the heat treatment process after curing. There was a problem that it was easy. In addition, in such applications, since dimensional stability is required, it is also required that the water absorption of the resin sheet is low, but in the conventional polyfunctional (meth) acrylate composition, the water absorption is relatively high. Met. Further, as a composition having no coloring and low water absorption, there is a composition containing di (meth) acrylate of an alkylene oxide adduct of bisphenol A. In this case, on the contrary, heat resistance However, there is a problem in that

Further, in the active energy ray curing reaction utilizing radical polymerization, it is difficult to improve the reaction rate after curing to nearly 100%, which is not satisfactory in the field where higher physical properties are required. It was For example,
When the obtained cured product is to be applied to liquid crystal related fields, the temperature after forming the liquid crystal alignment film is usually 150 ° C. or higher in the step after the resin sheet is produced, and unreacted ethylene in the cured product is not reached. If there is a polyunsaturated group, there is a problem in that it reacts here, and the resin sheet may shrink and color, as well as deteriorate in solvent resistance.

Therefore, the present inventors have found that the obtained resin sheet is excellent in heat resistance and transparency, has a low water absorption rate, has no coloring problem, and has an active energy ray-curable resin sheet forming agent, and further has excellent solvent resistance. An intensive study was conducted to find an active energy ray-curable resin sheet forming agent, particularly an active energy ray-curable resin sheet forming agent for producing a resin sheet suitable for an optoelectronic element.

[0007]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a sheet forming agent containing di (meth) acrylate having a specific structure is
It has excellent heat resistance, is transparent, has no color after heat treatment, and can form a resin sheet with extremely low water absorption, and when solvent resistance is required, by incorporating a thermal polymerization initiator. The inventors have found that this problem can be solved and completed the present invention. Hereinafter, the present invention will be described in detail. still,
In the present specification, acrylate or methacrylate is referred to as (meth) acrylate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION (A) Di (meth) acrylate The sheet forming agent of the present invention contains di (meth) acrylate represented by the following general formula (1).

[0009]

[Chemical 2]

[In the formula (1), R ¹ is an alkylene group, R ^1
2 is a hydrogen atom or a methyl group, and a and b are each independently an integer of 1 to 5. R ¹ is an alkylene group, and an alkylene group having 1 to 4 carbon atoms such as a methylene group, an ethylene group and a propylene group is preferable.

As a specific example of the component (A), in the formula (1),
R ¹ is an ethylene group, R ² is a hydrogen atom, a and b are bisphenoxyethanol full orange acrylates each of 1, or R ¹ is an ethylene group, R ² is a methyl group, and a and b are each 1, Bisphenoxyethanol full orange acrylate, R ¹ is a propylene group, R ² is a hydrogen atom, and a and b are each 1, and bisphenoxyisopropanol full orange acrylate, R
Examples thereof include bisphenoxyisopropanol full orange methacrylate in which ¹ is a propylene group, R ² is a methyl group, and a and b are 1 each.

(B) Photopolymerization Initiator The sheet forming agent of the present invention is cured by irradiation with active energy rays such as electron rays, visible rays and ultraviolet rays, but a resin sheet having a large film thickness can be obtained. In order to be able to do so, it is preferable to use a visible light or ultraviolet ray curable type.
When the visible light or ultraviolet ray curable forming agent is used, the photopolymerization initiator of the component (B) is blended with the forming agent. In the case of using the electron beam curable forming agent, it is not always necessary to mix the component (B). Specific examples of the component (B) include benzoin such as benzoin, benzoin methyl ether and benzoin propyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1. -Acetophenone such as dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one and N, N-dimethylaminoacetophenone; 2-methyl Anthraquinones such as anthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,
Thioxanthones such as 4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone, methylbenzophenone, 4,4′-dichlorobenzophenone,
Benzophenones such as 4,4'-bisdiethylaminobenzophenone, Michler's ketone and 4-benzoyl-4'-methyldiphenyl sulfide; and 2,4,6
-Trimethylbenzoyldiphenylphosphine oxide and the like can be mentioned. The component (B) may be used alone or in combination of two or more kinds. If necessary, a photosensitizer can be used in combination with the component (B). As a photosensitizer,
N, N-dimethylaminobenzoic acid ethyl ester, N,
Examples include N-dimethylaminobenzoic acid isoamyl ester, triethylamine, triethanolamine and the like.

(C) Thermal Polymerization Initiator In the present invention, it is preferable to incorporate the thermal polymerization initiator as the component (C) in applications where the resin sheet is required to have solvent resistance. As the component (C), various compounds can be used, and specific examples thereof include organic peroxides and azo compounds. Specific examples of the organic peroxide include 1,
1-bis (t-butylperoxy) 2-methylcyclohexane, 1,1-bis (t-hexylperoxy)-
3,3,5-Trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-
Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (4,4-di-butylperoxycyclohexyl) propane , 1,1-bis (t-butylperoxy) cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,
5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-
Toluoyl peroxy) hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5
-Di (benzoylperoxy) hexane, t-butylperoxyacetate, 2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n
-Butyl-4,4-bis (t-butylperoxy) valerate, di-t-butylperoxyisophthalate,
α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t
-Butyl cumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,
5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, diisopropylbenzene hydroperoxide, t-butyltrimethylsilyl peroxide,
1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide and the like can be mentioned. Specific examples of the azo compound include 1,1′-azobis (cyclohexane-1-carbonitrile), 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile. , Azodi-t-octane, azodi-
Examples include t-butane and the like. These may be used alone or in combination of two or more. Further, the redox reaction can be carried out by combining the organic peroxide with a reducing agent.

(D) Other components The sheet forming agent of the present invention contains the component (A) as an essential component, but if necessary, a radical polymerizable monomer other than the component (A) (hereinafter Other monomers) can be blended. Other monomers include (meth) acrylates having one (meth) acryloyl group [hereinafter referred to as monofunctional (meth) acrylates] (meth) acrylates having two or more (meth) acryloyl groups [hereinafter referred to as Functional (meth) acrylate], epoxy (meth) acrylate, polyurethane (meth) acrylate, polyester (meth) acrylate, polybutadiene (meth) acrylate, and the like.

The monofunctional (meth) acrylate is 2
-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, tricyclodecane mono (meth) acrylate, isobornyl (meth) acrylate and the like can be mentioned. As the polyfunctional (meth) acrylate, hexanediol di (meth) acrylate,
Nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate and dipentaerythritol, and these Examples thereof include poly (meth) acrylates of alkylene oxide adducts of raw material alcohols of (meth) acrylate, and poly (meth) acrylates of alkylene oxide adducts of isocyanuric acid. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

As the epoxy (meth) acrylate,
(Meth) acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether and triglycidyl isocyanurate, and epoxy resins such as bisphenol A type epoxy resin, phenol novolac type epoxy resin and cresol novolac type epoxy resin (meta) ) Acrylate and the like.

Examples of polyurethane (meth) acrylates include reaction products of polyhydric alcohols, polyvalent isocyanate compounds, and hydroxyl group-containing (meth) acrylates. Examples of the polyhydric alcohol include polyether polyols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and polyester diols such as ethylene glycol adipate, butanediol adipate, butanediol phthalate and hexanediol phthalate. Examples of the polyvalent isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and hydrogenated diphenylmethane diisocyanate. As the hydroxyl group-containing (meth) acrylate, hydroxyethyl (meth) acrylate and hydroxypropyl (meth)
Examples thereof include hydroxyalkyl (meth) acrylates such as acrylates.

Examples of the polyester (meth) acrylate include a reaction product of a polyester type polyhydric alcohol and (meth) acrylic acid. Examples of polyester type polyhydric alcohols include polybasic acids such as succinic acid, maleic acid, adipic acid, sebacic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and trimellitic acid, and anhydrides thereof. Can be mentioned. The alcohol component, ethylene glycol, butanediol, hexanediol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylol propane, pentaerythritol, ethylene oxide of trimethylol propane, or triol of propylene oxide adduct, ethylene oxide of glycerin, Or triol of propylene oxide adduct, and ethylene oxide of pentaerythritol,
Alternatively, a polyester alcohol obtained by reacting propylene oxide adduct tetraol or the like may be used.

The amount of the other monomer used is 0 to 0 in the composition.
The amount is preferably 50% by mass, more preferably 15% by weight or less. When the use ratio of these is high, the water absorption of the obtained resin sheet may be extremely increased or the solvent resistance may be decreased.

Further, a mercapto compound having two or more thiol groups in the molecule may be added to the composition for the purpose of reducing the birefringence of the obtained resin sheet. Specific examples of the mercapto compound include pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (thioglycolate), trimethylolpropane tris (β-thiopropionate), trimethylolpropane tris (thioglycol). Rate), diethylene glycol bis (β-thiopropionate), diethylene glycol bis (thioglycolate), triethylene glycol bis (thioglycolate), dipentaerythritol hexakis (β-thiopropionate) and dipentaerythritol hexa Kiss (thioglycolate) and the like can be mentioned. The mercapto compounds may be used alone or in combination of two or more. The blending ratio of the mercapto compound is preferably 5% by mass or less. If it exceeds 5% by mass, the heat resistance of the obtained resin sheet may decrease.

(E) Method for Producing Sheet Forming Agent In the sheet forming agent of the present invention, in the case of curing with an electron beam, only the component (A) is required, and the component (B) or / and the component (C) and others. In the case of using the components described in 1 above, they can be obtained by mixing the components according to a conventional method. In the sheet forming agent of the present invention, when the other monomer is used, the proportion of the component (A) in the sheet forming agent is preferably 50% by mass or more. When the component (B) is blended, the proportion is preferably 0.05 to 12% by mass, and more preferably 0.1 to 2% by mass, relative to 100 parts by mass of the component (A). When the component (C) is blended, the proportion is 0.01 to 100 parts by mass of the component (A).
It is preferably 10% by mass, more preferably 0.1 to 2% by mass. If this ratio is less than 0.01% by mass, the sufficient effect of thermosetting may not be obtained, while 1
If it exceeds 0% by mass, internal stress may be accumulated in the sheet due to a rapid reaction, or the obtained resin sheet may be colored.

(F) Method for producing resin sheet As a method for producing a resin sheet using the sheet forming agent of the present invention, a conventional method may be used. For example, two flat plates that can transmit active energy rays are used, and a space portion is formed by using resin plates or the like on four sides of the flat plate, and the peripheral portion is sealed as necessary, and then the composition is placed in the space portion. And the active energy ray is transmitted through the flat plate to irradiate and cure. After curing, the two flat plates are removed to obtain a resin sheet. When using a mixture of the component (C) as a sheet forming agent, after irradiating with the active energy ray,
Heating.

Examples of active energy rays include electron rays, visible rays and ultraviolet rays. The light source for irradiation with visible light and ultraviolet light may be appropriately selected according to the photopolymerization initiator used, and examples thereof include a high pressure mercury lamp and a metal halide lamp.

When the heating step is performed after irradiation with active energy rays, the cured product obtained by irradiation with active energy rays may be heated after removing the two flat plates, or may be heated continuously without removing the flat plates. . A conventionally used dryer can be used for heating. The dryer is preferably one capable of passing an inert gas such as nitrogen or argon, and the shape and specifications are not limited. The gas flow rate is not particularly limited as long as the inside of the dryer is sufficiently replaced with the inert gas. The heating temperature is preferably 60 to 250 ° C, more preferably 180 to 230 ° C. If the heating temperature is lower than 60 ° C, the component (B) may not be sufficiently decomposed, or the heat-curing rate of the cured product after irradiation with active energy rays may be insufficient, while if it exceeds 250 ° C. In some cases, the main chain skeleton of the resin sheet or the ester portion may be decomposed. If the heating time is too short, a sufficient effect may not be obtained, and if it is too long, productivity and work efficiency may be significantly reduced. Usually 10 minutes
It is preferably 2 hours, more preferably 30 minutes to 1 hour. However, the time can be shortened when the desired reaction rate does not have to be close to 100%, and the time can be lengthened when the purpose is to alleviate strain of the cured product. Cooling after heat-curing is preferably lowered gradually to room temperature, because a sheet having a higher glass transition temperature (Tg) of the cured product tends to be broken by rapid cooling.

The flat plate is preferably one that does not hinder the transmission of light and is not deformed by the heat generated by the lamp or the heat of polymerization. Suitable examples include hard glass, and those having equivalent performance to hard glass,
It is also possible to use a resin plate or the like. If necessary, in order to easily remove the resin sheet obtained in the space, various release agents may be applied to the flat plate or a release layer may be provided. These are not particularly limited as long as they do not hinder the transmission of light and do not cause deformation by heat during light irradiation.

[0026]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1 to 4 ○ Production of sheet forming agent A sheet forming agent was produced by mixing the components (A) and (B) shown in Table 1 below.

Production of Resin Sheet A resin plate was placed on each side of a glass flat plate to form a space having a thickness of 0.4 mm. After filling the space with the obtained forming agent, a glass flat plate was placed thereon. This was irradiated with ultraviolet rays under a condition of 0.8 J / cm ² with a high-pressure mercury lamp having a conveyor speed of 5 m / min and an output of 160 W / cm, 5 times for each of the front and back surfaces of the glass plate. After curing, the glass flat plate was removed to obtain a resin sheet having a thickness of 0.4 mm. The obtained resin sheet was used and evaluated according to the methods described below. The results obtained are shown in Table 1.

○ Evaluation / Coloring The obtained resin sheet was heated at 210 ° C. for 1 hour and cooled, and then the transparency of the material was visually confirmed, and JIS K 5
Accelerated yellowness was measured according to 400 and evaluated. As the color difference meter, SZ optical sensor manufactured by Nippon Denshoku Industries Co., Ltd. was used.

Heat resistance The viscoelastic spectrum of the obtained resin sheet is measured,
The obtained tan δmax value was taken as the glass transition point (hereinafter referred to as Tg) to evaluate the heat resistance.

Water absorption The obtained resin sheet was cut into a piece of 5 cm × 5 cm and used as a test piece. The test piece was heated in nitrogen at 210 ° C. for 1 hour to completely dry the cured product, and then allowed to cool in a desiccator, and the test piece was weighed (W1). Then, the test piece was immersed in distilled water at 80 ° C. for 20 hours, taken out, and then water on the surface of the test piece was wiped off and weighed (W2), and the water absorption rate was calculated from the following formula.

[0032]

[Formula 1] Water absorption rate (%) = 100 × (W2-W1) / W1

[0033]

[Table 1]

The abbreviations in Table 1 have the following meanings. 1) BPEFDA: bisphenoxyethanol full orange acrylate 2) BPPFDA: bisphenoxyisopropanol full orange acrylate 3) HCCP: 1-hydroxycyclohexyl phenyl ketone 4) BDKM: benzyl dimethyl ketal

Comparative Examples 1 to 3 Using the compounds shown in Table 2 below as raw materials, a forming agent was produced in the same manner as in Examples, and resin sheets obtained in the same manner as in Examples were evaluated. . The obtained results are shown in Table 2.

[0036]

[Table 2]

The abbreviations in Table 2 are the same as those in Table 1 except for the following.
Has the same meaning as. 1) IBA: isobornyl acrylate 2) TPDA: tripropylene glycol diacrylate 3) M-211B: Aronix M- manufactured by Toagosei Co., Ltd.
211B, diacrylate of bisphenol A ethylene oxide 4 mol adduct

Examples 5 to 8 Using the compounds shown in Table 3 below as raw materials, a forming agent was produced in the same manner as in the above Examples. Using the obtained sheet forming agent, ultraviolet irradiation in the same manner as in the above example,
The cured product after ultraviolet curing was allowed to stand for 1 hour in a dryer that had been previously purged with nitrogen and heated. Using the obtained resin sheet, the following evaluation was performed in addition to the same evaluations as in the above-mentioned examples. The obtained results are shown in Tables 3 and 4.

Measurement of reaction rate The reaction rate was measured by Raman spectrum measurement.
The reaction rate was calculated by absorption of carbonyl in di (meth) acrylate before and after curing (approximately 1690 to 1770).
cm ^-1 ) and ethylenic double bond (approximately 1620-16
It was determined from the intensity ratio of 60 cm ^-1 ). That is, the absorption intensity of carbonyl remains unchanged before and after curing, but the absorption intensity of the double bond decreases with the progress of the reaction, so the reaction rate can be known.

Solvent resistance The obtained resin sheet was cut into 1 cm × 1 cm and used as a test piece. After measuring the weight of the test piece, it was immersed in methyl ethyl ketone (hereinafter referred to as MEK) and refluxed for 3 hours. After refluxing, the test piece was taken out, the surface MEK was wiped off with paper, and then the weight was measured to obtain the weight reduction rate before and after the reflux.

[0041]

[Table 3]

The abbreviations in Table 3 are the same as those in Table 1 except for the following.
Has the same meaning as. 1) PB-D: Perbutyl D, di-t manufactured by NOF CORPORATION
-Butyl peroxide 2) PO-D: Perocta H, 1, manufactured by NOF CORPORATION
1,3,3-Tetrabutyl hydroperoxide

[0043]

[Table 4]

Reference Examples 1 to 3 For reference, the sheet forming agents of Examples 1 to 3 were used,
In the same manner as in Examples 5 to 8, UV irradiation was performed and heat treatment was performed. Example 5 using the obtained resin sheet
~ Evaluated in the same manner as in 8 above. The obtained results are shown in Tables 5 and 6. By comparing Examples 5 to 8 and Reference Example,
It can be seen that when the component (C) is blended, the resin sheet becomes more excellent in solvent resistance.

[0045]

[Table 5]

[0046]

[Table 6]

[0047]

EFFECTS OF THE INVENTION The sheet forming agent of the present invention is such that the resin sheet obtained is excellent in heat resistance, is transparent and has no color, and has a very low water absorption rate. Is also excellent. Further, the obtained resin sheet is lighter in weight and more excellent in impact resistance than a glass substrate, and is used as an optical resin sheet such as an alternative sheet component for a glass substrate such as a liquid crystal display, a polarizing film for a liquid crystal display and a laminated sheet for a touch panel. It is particularly useful and has a great industrial utility value.

Continued front page    (72) Inventor Yutaka Matsuda             5 residences, 1-1 Muroya, Nishi-ku, Kobe City, Hyogo Prefecture             Tomo Bakelite Co., Ltd. Kobe Basic Research Center (72) Inventor Junji Tanaka             5 residences, 1-1 Muroya, Nishi-ku, Kobe City, Hyogo Prefecture             Tomo Bakelite Co., Ltd. Kobe Basic Research Center F-term (reference) 4J027 AC02 AC06 AJ08 BA08 BA09                       BA19 BA24 BA27 CC03 CD04                 4J100 AL08P BA07P BC43P BC48P                       CA01 CA04 JA32 JA33

Claims (3)

[Claims] 1. An active energy ray curable resin sheet forming agent comprising (A) a di (meth) acrylate represented by the following general formula (1). [Chemical 1] [In Formula (1), R ¹ is an alkylene group, R ² is a hydrogen atom or a methyl group, and a and b are each independently an integer of 1 to 5. ] 2. The active energy ray-curable resin sheet forming agent according to claim 1, further comprising (B) a photopolymerization initiator. 3. The active energy ray-curable resin sheet forming agent according to claim 1, further comprising (C) a thermal polymerization initiator.