JP7257815B2 - Urethane (meth)acrylate, active energy ray-curable composition containing the same, and cured product thereof - Google Patents

Description

The present invention provides a urethane (meth)acrylate and an active energy ray-curable composition (OCR: Optical Clear Resin) that can be used as an interlayer filler for base materials for displays such as personal computers, televisions, and mobile phones. and a cured product of the active energy ray-curable composition.

The displays used in personal computers, car navigation systems, televisions, mobile phones, etc. show images with light from backlights. Displays use glass substrates such as glass plates and transparent substrates such as plastic substrates such as plastic films. may reduce the amount of light received. If the decrease in the amount of light becomes large, the screen becomes dark and the visibility deteriorates.

Methods for improving the visibility include increasing the light scattering prevention property of the display surface layer, increasing the amount of light from the light source, and the like. As one of the specific methods, there is a method of replacing an air layer between transparent substrates such as glass substrates and plastic substrates with a resin layer (cured resin layer). By replacing the air layer with a resin layer, light scattering at the interface between the air and the transparent substrate can be prevented, so it is possible to prevent a decrease in the amount of light output from the light source to the outside of the display, thereby improving visibility.

The performance required for the resin used between the layers of the transparent base material is high adhesion to the base material, deformation resistance, and flexibility, as well as high transparency, specifically, a light transmittance of 95% at 400 nm. or more. In addition, it is required to have high heat resistance, specifically, to exhibit little change in shape and hue when exposed to 95°C. Various urethane (meth)acrylates have been proposed for the purpose of imparting such properties to cured products.

Japanese Patent No. 1041553 Japanese Patent No. 2582575 Japanese Patent Application Laid-Open No. 2002-069138 Japanese Patent Application Laid-Open No. 2002-309185 JP 2003-155455 A Japanese Patent Application Laid-Open No. 2010-144000 JP 2010-254890 A JP 2010-254891 A JP 2010-265402 A JP 2011-116965 A JP 2013-129812 A

For example, urethane (meth)acrylates containing hydrogenated polyolefin polyols as constituents and active energy ray-curable compositions containing these have been reported (Patent Documents 1 to 10). Using a hydrogenated polyolefin polyol as a component of urethane (meth)acrylate is very effective from the viewpoint of preventing deterioration of the cured product due to oxidation. However, since such urethane (meth)acrylates have high hydrophobicity, they tend to have poor compatibility with other components that may be contained in the composition. It has been difficult to impart the desired properties (for example, flexibility, heat resistance, etc.). In addition, since the hydrogenated polyolefin polyols described above are expensive and have high viscosity, there are problems such as difficulty in producing urethane (meth)acrylates on a large scale and poor handling. rice field.

In order to overcome such drawbacks, it is known to adjust the viscosity by adding a low-viscosity monofunctional (meth)acrylate as a compatibilizer or diluent during the production of urethane (meth)acrylate. (Patent Document 11). However, the monofunctional (meth)acrylate that can be used and the amount thereof are limited, and depending on the amount, it may become a shape that part of it melts out when cured (hereinafter referred to as such shape change (sometimes referred to as "melt"). Furthermore, the above-mentioned urethane (meth)acrylate has a problem that the heat resistance of the cured product is low, and specifically, the shape and hue of the cured product are likely to change when the cured product is subjected to high temperatures. .

In addition to hydrogenated polyolefin polyols, polypropylene glycol and the like are also used as constituents of urethane (meth)acrylates. Polypropylene glycol is obtained by addition polymerization of propylene oxide (PO) to a polyhydric alcohol such as propylene glycol. In polypropylene glycol obtained by such a polymerization reaction, most of the terminal hydroxyl groups (about 95 mol %) are generally secondary hydroxyl groups. Since such polypropylene glycol is inferior in reactivity, when it is used in the urethanization reaction, it is common to add ethylene oxide (EO) to primaryize the terminal hydroxyl groups. However, since ethylene oxide has a high affinity for water, the resulting urethane resin tends to be highly hydrophilic. As a result, the cured product of urethane (meth)acrylate containing such polypropylene glycol as a component tends to decompose the urethane bond after long-term use, resulting in a large decrease in water resistance and insufficient heat resistance. There is

Therefore, an object of the present invention is to provide a urethane (meth)acrylate that imparts high flexibility and heat resistance while imparting high adhesion and transparency to a cured product, and an active energy ray-curable composition containing the same It is about providing things. Another object of the present invention is to provide a cured product having high flexibility and heat resistance while providing high adhesion and transparency, and a laminate containing the cured product.

As a result of intensive studies to achieve the above object, the present inventors have found that a cured product of urethane (meth)acrylate having a specific configuration exhibits high flexibility and heat resistance, and thus contains the urethane (meth)acrylate. The inventors have found that an active energy ray-curable composition is useful as an interlayer filling curable composition for transparent substrates such as glass substrates and plastic substrates, and completed the present invention.

That is, the present invention provides a urethane (meth)acrylate containing polypropylene glycol (A), polyisocyanate (B), and hydroxyl group-containing (meth)acrylate (C) as structural units, wherein the polypropylene glycol (A) is Provided is a urethane (meth)acrylate characterized by being polypropylene glycol (excluding ethylene oxide adducts of polypropylene glycol) having a ratio of primary hydroxyl groups in terminal hydroxyl groups of 20 mol % or more.

The weight average molecular weight of the polypropylene glycol (A) is preferably 1500 or more.

The present invention also provides an active energy ray-curable composition containing the urethane (meth)acrylate and a photopolymerization initiator.

The active energy ray-curable composition is preferably for interlayer filling.

The present invention also provides a cured product of the active energy ray-curable composition.

In the present invention, a laminate having a cured product layer of the active energy ray-curable composition between a first transparent substrate selected from glass and plastic and a second transparent substrate selected from glass and plastic. We also provide

By incorporating the urethane (meth)acrylate of the present invention into the active energy ray-curable composition, it is possible to impart good flexibility and heat resistance to the cured product. In addition, the active energy ray-curable composition of the present invention exhibits good flexibility and heat resistance in its cured product.

In addition, by filling the active energy ray-curable composition of the present invention between the transparent substrates and curing, it is possible to prevent light scattering at the interface between the air and the transparent substrate, and furthermore, change in hue and shape during the heat resistance test. It is possible to obtain a flexible laminate that is less likely to cause sagging. Therefore, the active energy ray-curable composition of the present invention is useful as an interlayer filler for displays used in personal computers, car navigation systems, televisions, mobile phones (smartphones, etc.), tablets, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows one aspect|mode of the laminated body of this invention. It is a schematic diagram showing the mode of the test piece A used in the present example. It is a schematic diagram showing the mode of test piece B used in the present example. In the figure, (A) is a top view of the glass laminate, and (B) is a side view of the glass laminate.

<Urethane (meth)acrylate (X)>
The urethane (meth)acrylate (X) of the present invention is a urethane (meth)acrylate containing polypropylene glycol (A), polyisocyanate (B), and hydroxyl group-containing (meth)acrylate (C) as structural units, The polypropylene glycol (A) is characterized by being a polypropylene glycol having a ratio of primary hydroxyl groups in the terminal hydroxyl groups of 20 mol % or more (excluding ethylene oxide adducts of polypropylene glycol). That is, the urethane (meth)acrylate (X) of the present invention is a polypropylene glycol having a primary hydroxyl group ratio of 20 mol% or more in the terminal hydroxyl group, and is not an ethylene oxide adduct of polypropylene glycol ( A) (hereinafter sometimes simply referred to as "polypropylene glycol (A)"), a polyisocyanate (B), and a urethane (meth)acrylate obtained by reacting a hydroxyl group-containing (meth)acrylate (C) be.

Urethane (meth)acrylate (X) may further contain structural units other than polypropylene glycol (A), polyisocyanate (B), and hydroxyl group-containing (meth)acrylate (C). An alcohol (D) having a hydroxyl group may be included as a structural unit. That is, urethane (meth)acrylate (X) is obtained by reacting polypropylene glycol (A), polyisocyanate (B), hydroxyl group-containing (meth)acrylate (C), and alcohol (D) having one hydroxyl group. It may be a urethane (meth)acrylate obtained by

The urethane (meth)acrylate (X) may contain a urethane prepolymer containing polypropylene glycol (A) and polyisocyanate (B) as structural units, and a hydroxyl group-containing (meth)acrylate (C) as structural units. That is, urethane (meth)acrylate (X) is formed by reacting polypropylene glycol (A) and polyisocyanate (B) to form a urethane prepolymer, and then combining the urethane prepolymer with hydroxyl group-containing (meth)acrylate (C). Urethane (meth)acrylate obtained by reacting may be used.

The urethane prepolymer having the isocyanate group is called "urethane prepolymer", the polypropylene glycol (A) is called "(A)", the polyisocyanate (B) is called "(B)", and the hydroxyl group is The contained (meth)acrylate (C) is referred to as "(meth)acrylate (C)" or "(C)", and the alcohol (D) having one hydroxyl group is referred to as "alcohol (D)" or "(D)". Sometimes.

The viscosity of the urethane (meth)acrylate (X) at 60° C. is not particularly limited, but for example, it is preferably from 100 to 300000 mPa·s, more preferably from 500 to 200000 mPa·s, still more preferably from 1000 to 100000 mPa·s. be. When the viscosity of the urethane (meth)acrylate (X) at 60°C is within the above range, the handleability tends to be improved. The viscosity of the urethane (meth)acrylate (X) can be measured at 60° C. using, for example, an E-type viscometer (Toki Sangyo, Model TV-25).

Although the weight average molecular weight (Mw) of the urethane (meth)acrylate (X) is not particularly limited, it is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, still more preferably 8,000 to 200,000. When the weight-average molecular weight is within the above range, the cured product tends to exhibit good flexibility and the appearance of the resin is good. In particular, when the weight-average molecular weight (Mw) of the urethane (meth)acrylate (X) is less than 2,000, the flexibility tends to decrease, the appearance of the resin deteriorates, and the amount of by-products tends to increase. On the other hand, if it exceeds 500,000, the crosslink density tends to decrease, resulting in deterioration of curability. The "weight-average molecular weight" in the present invention can be expressed as a polystyrene-equivalent value obtained by GPC measurement, and can be measured, for example, by the method described in Examples below.

[Polypropylene glycol (A)]
Polypropylene glycol (A) is not particularly limited as long as the ratio of primary hydroxyl groups in terminal hydroxyl groups is 20 mol % or more and it does not correspond to ethylene oxide adducts of polypropylene glycol. Polypropylene glycol (A) may be used alone or in combination of two or more.

Polypropylene glycol (A) excludes ethylene oxide adducts of polypropylene glycol (ethylene oxide-modified polypropylene glycol). That is, it is characterized in that it is not obtained by addition polymerization of ethylene oxide to polypropylene glycol. As described above, polypropylene glycol is obtained by addition polymerization of propylene oxide to a polyhydric alcohol such as propylene glycol, and generally most of its terminal hydroxyl groups (about 95 mol%) are secondary hydroxyl groups. However, since such polypropylene glycol is inferior in reactivity, ethylene oxide is added to convert the terminal hydroxyl groups to primary groups, which are used in the urethanization reaction. However, since ethylene oxide has a high affinity for water, a cured product of urethane (meth)acrylate containing polypropylene glycol as a structural unit tends to have significantly lower water resistance and insufficient heat resistance. Tend. On the other hand, the polypropylene glycol (A) of the present invention improves the reactivity in the urethanization reaction by adjusting the ratio of the primary hydroxyl group in the terminal hydroxyl group to a specific value without adding ethylene oxide, and the resulting urethane It imparts heat resistance to the cured product of (meth)acrylate.

The ratio of primary hydroxyl groups in the terminal hydroxyl groups of polypropylene glycol (A) is not particularly limited as long as it is 20 mol% or more, but for example, it is preferably 20 to 95 mol%, more preferably 30 to 90 mol%, and further Preferably 40 to 80 mol %, particularly preferably 50 to 70 mol %, most preferably 60 to 65 mol %. When the ratio is within the above range, the resulting urethane (meth)acrylate cured product tends to have improved heat resistance and exhibits appropriate flexibility.

Although the weight average molecular weight (Mw) of polypropylene glycol (A) is not particularly limited, for example, it is preferably 1500 or more, more preferably 1600 to 3000, still more preferably 1700 to 2500, and particularly preferably 1800 to 2000. . When the weight-average molecular weight is within the above range, the obtained urethane (meth)acrylate cured product tends to have improved flexibility and heat resistance. In particular, when the weight average molecular weight (Mw) of the polypropylene glycol (A) is less than 1500, the flexibility of the resulting urethane (meth)acrylate cured product tends to decrease and the appearance of the resin tends to deteriorate.

Polypropylene glycol (A) may be a commercially available product such as "Primepol FF2202" manufactured by Sanyo Chemical Industries, Ltd., and the like.

The urethane (meth)acrylate (X) of the present invention may contain a polyol other than polypropylene glycol (A) as a constituent component. That is, the urethane (meth)acrylate (X) of the present invention is a reaction of polypropylene glycol (A) and a polyol other than polypropylene glycol (A), polyisocyanate (B), and hydroxyl group-containing (meth)acrylate (C). It can be a thing.

Polyols other than polypropylene glycol (A) include, for example, polyalkylene glycols other than polypropylene glycol (A), polyolefin polyols, hydrogenated polyolefin polyols, polyester polyols, trimethylolpropane, pentaerythritol, glycerin, butylethylpropanediol, and These modified substances etc. are mentioned.

Commercially available polyols other than polypropylene glycol (A) may be used, for example, "Trimethylolpropane (TMP)" manufactured by Mitsubishi Gas Chemical Co., Ltd., "Butylethylpropanediol (BEPD)" manufactured by KH Neochem Co., Ltd. , Sanyo Chemical Industries, Ltd. "Sannics HD-402 (polypropylene glycol modified product of pentaerythritol)", "Sannics HD-250 (polypropylene glycol modified glycerin)", Idemitsu Kosan Co., Ltd. "Epol" , "GI-2000", "GI-3000" and "G-3000" manufactured by Nippon Soda Co., Ltd., and "KRASOL HLBH P3000" and "KRASOL LBH-P2000" manufactured by Nagase & Co., Ltd., and the like.

[Polyisocyanate (B)]
Polyisocyanate (B) is not particularly limited, and examples thereof include aliphatic polyisocyanate and aromatic polyisocyanate. Among these, aliphatic polyisocyanates are preferable from the viewpoint of heat resistance (color change). That is, when an aromatic polyisocyanate is used, the cured product tends to yellow at high temperatures compared to when an aliphatic polyisocyanate is used. preferable. One type of polyisocyanate may be used alone, or two or more types may be used in combination.

Aliphatic polyisocyanates include, for example, cycloaliphatic polyisocyanates and linear or branched aliphatic polyisocyanates. Examples of alicyclic polyisocyanates include alicyclic diisocyanates such as isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate (dicyclohexylmethane 4,4′-diisocyanate), and aromatic polyisocyanates such as hydrogenated xylylene diisocyanate ( alicyclic polyisocyanates obtained by hydrogenation). Examples of aliphatic polyisocyanates include linear aliphatic diisocyanates such as hexamethylene diisocyanate, branched aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate. is mentioned.

Examples of aromatic polyisocyanates include aromatic diisocyanates such as diphenylmethane diisocyanate, aromatic triisocyanates, and aromatic tetraisocyanates.

Polyisocyanate (B) may be a commercially available product, for example, Evonik Co., Ltd. "VESTANAT IPDI (isophorone diisocyanate)", "TMDI (2,2,4-trimethylhexamethylene diisocyanate)", Sumika Bayer ( "Hydrogenated MDI (HMDI, dicyclohexylmethane 4,4'-diisocyanate)" manufactured by Nippon Polyurethane Co., Ltd. "HDI (hexamethylene diisocyanate)", "MDI (diphenylmethane diisocyanate)" manufactured by Evonik Co., Ltd. TMHDI (a mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate)” and the like.

[(Meth)acrylate (C)]
(Meth)acrylate (C) is not particularly limited as long as it is a hydroxyl group-containing (meth)acrylate, but examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate (2-hydroxy ) acrylate), 4-hydroxybutyl (meth) acrylate, etc. (meth) acrylates having one (meth) acryloyl group and further containing one hydroxyl group; two or more (meth) acryloyl groups such as pentaerythritol triacrylate (Meth)acrylates which have a group and additionally contain one hydroxyl group are preferred. (Meth)acrylate (C) may be used alone or in combination of two or more.

(Meth)acrylate (C) may be a commercially available product, for example, Nippon Shokubai Co., Ltd. "β-HEA 2-hydroxyethyl acrylate (HEA)", "2-hydroxypropyl acrylate (HPA)" etc.

[Alcohol (D)]
Alcohol (D) is not particularly limited as long as it is an alcohol having one hydroxyl group. A primary alcohol is preferred. (Meth)acrylate (C) is not included in alcohol (D). If the molecular weight of the alcohol is less than 70 or the number of carbon atoms is less than 3, the alcohol may volatilize during production of the urethane (meth)acrylate, which is not preferable. On the other hand, if the molecular weight exceeds 400, the reactivity with the isocyanate group tends to decrease and the reaction time tends to become long, which is not preferable. Also, alcohols having an aromatic ring are not preferable because the cured product tends to yellow due to heat. Alcohol (D) may be used individually by 1 type, and may use 2 or more types together.

Examples of alcohol (D) include 1-butanol, 1-heptanol, 1-hexanol, normal octyl alcohol, 2-ethylhexyl alcohol, cyclohexanemethanol, capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol (cetanol), and stearyl alcohol. is mentioned. Among these, 2-ethylhexyl alcohol is preferred from the viewpoint of boiling point, price, and availability.

[Method for producing urethane (meth)acrylate (X)]
The method for producing urethane (meth)acrylate (X) of the present invention (hereinafter sometimes referred to as “the production method of the present invention”) comprises polypropylene glycol (A), polyisocyanate (B), and (meth)acrylate (C) is reacted (urethanization reaction).

The production method of the present invention is not particularly limited, but after forming a urethane prepolymer by reacting polypropylene glycol (A) and polyisocyanate (B), the urethane prepolymer and (meth)acrylate (C ) to produce a urethane (meth)acrylate. When reacting the urethane prepolymer and the (meth)acrylate (C), the alcohol (D) may be used together with the (meth)acrylate (C).

When forming the urethane prepolymer (that is, when subjecting the polypropylene glycol (A) and the polyisocyanate (B) to the reaction), the monofunctional (meth)acrylate (Y) (hereinafter referred to as "(meth)acrylate (Y )”) may be used as a compatibilizer or diluent. (Meth)acrylate (Y) acts as a compatibilizer or diluent for polypropylene glycol (A) and polyisocyanate (B), so that the reaction of the above components tends to proceed smoothly. (Meth)acrylate (Y) may also act as a compatibilizer or diluent between the urethane prepolymer and (meth)acrylate (C). The reaction process tends to proceed smoothly.

Moreover, the viscosity of the reaction liquid may increase when forming the urethane prepolymer, but the use of (meth)acrylate (Y) can mitigate the increase in the viscosity of the reaction liquid. Furthermore, the viscosity of the reaction solution may increase during the reaction between the urethane prepolymer and the (meth)acrylate (C). An increase in the viscosity of the liquid can be mitigated.

The above production method, that is, "method of reacting (A) and (B) and then reacting (C)" is "mixing (A), (B), and (C) together Compared to the "method of reacting with (B) and (C) and then further reacting (A)", prevention of viscosity increase of the reaction product, suppression of by-products, curing of the cured product It is preferable from the viewpoint of improving transparency and heat resistance.

Specifically, the urethane (meth)acrylate obtained by the "method of mixing and reacting (A), (B), and (C) together" tends to have high viscosity. Moreover, since the reaction progresses unevenly, there is a tendency for partial gelation. Furthermore, urethane (meth)acrylate (that is, a by-product) that does not contain polypropylene glycol (A) in its skeleton is produced, which tends to cause a decrease in the light transmittance and flexibility of the cured product. And since various urethane (meth)acrylates are obtained, quality control tends to be difficult.

Further, in the "method of reacting (B) and (C) and then further reacting (A)", all the isocyanate groups of the polyisocyanate (B) reacted with the hydroxyl groups of the (meth)acrylate (C). Urethane (meth)acrylates (ie, by-products) tend to form. This by-product tends to exhibit crystallinity because it does not contain a polypropylene glycol (A) skeleton, which not only leads to a decrease in light transmittance at 400 nm, but also causes gelation of urethane (meth)acrylate. be.

Methods for forming the urethane prepolymer include the following methods 1 to 3.
[Method 1] A method in which polypropylene glycol (A) and polyisocyanate (B) are collectively mixed and reacted.
[Method 2] A method in which polypropylene glycol (A) is added dropwise into polyisocyanate (B) for reaction.
[Method 3] A method of reacting polyisocyanate (B) dropwise into polypropylene glycol (A).

In the case of [Method 1], polypropylene glycol (A) and polyisocyanate (B) are charged into a reactor and stirred until uniform. Thereafter, it is desirable to use a method in which the temperature is raised as necessary while stirring, and then a urethanization catalyst is added to initiate the reaction. After charging the urethanization catalyst, the temperature may be raised as necessary.

In [Method 1], (meth)acrylate (Y) may be used as a compatibilizer or diluent. In this case, polypropylene glycol (A) is charged into a reactor together with (meth)acrylate (Y), stirred until uniform, and then polyisocyanate (B) is charged and homogenized. As a result, the viscosity of the reaction solution can be further reduced. Thereafter, it is desirable to use a method in which the temperature is raised as necessary while stirring, and then a urethanization catalyst is added to initiate the reaction. After charging the urethanization catalyst, the temperature may be raised as necessary.

If the urethanization catalyst is added before the polypropylene glycol (A) and the polyisocyanate (B) are uniformly stirred, the reaction proceeds unevenly, causing problems such as gelation of the resulting urethane prepolymer. Tend. Furthermore, the reaction may be terminated with unreacted polyisocyanate (B) remaining in the system. In this case, it is not preferable because the light transmittance at 400 nm is lowered by a by-product obtained by reacting the (meth)acrylate (C) to be reacted later with the remaining polyisocyanate (B).

The content of by-products is preferably less than 7% by weight relative to the target urethane prepolymer. If it is 7% by weight or more, the light transmittance at 400 nm is remarkably lowered.

[Method 1] is industrially superior in that even if the polypropylene glycol (A) has a high viscosity, it can be charged into the reactor as it is, and in that the urethane prepolymer can be produced in one pot. Moreover, since the reaction is initiated in a state in which the polypropylene glycol (A) and the polyisocyanate (B) are uniformly mixed, the reaction progresses according to stoichiometry, which is excellent. Furthermore, it is effective in that a uniform urethane prepolymer can be obtained (for example, a urethane prepolymer with a narrow molecular weight distribution can be obtained) and that production reproducibility is high. On the other hand, in methods such as [Method 2] and [Method 3] described later, in which either one of polypropylene glycol (A) and polyisocyanate (B) is dropped and reacted, the reaction species in the system depends on the dropping time. Since the ratios are different, it is disadvantageous that a uniform urethane prepolymer cannot be obtained, that is, the obtained urethane prepolymer has a wide molecular weight distribution.

In the case of [Method 2], the reactor is charged with the polyisocyanate (B) and the urethanization catalyst, stirred until uniform, the temperature is raised as necessary, and the reaction is performed while dropping the polypropylene glycol (A). Characterized by

In [Method 2], (meth)acrylate (Y) may be used as a compatibilizer or diluent. Specifically, the polyisocyanate (B), the urethanization catalyst, and the (meth)acrylate (Y) are charged and stirred until uniform. Thereafter, the temperature is raised as necessary, and the reaction is carried out while dripping polypropylene glycol (A) or a homogeneous mixture of polypropylene glycol (A) and (meth)acrylate (Y).

In the case of [Method 3], the polypropylene glycol (A) and the urethanization catalyst are charged into the reactor, stirred until uniform, the temperature is raised as necessary, and the polyisocyanate (B) is added dropwise to react. Characterized by

In [Method 3], (meth)acrylate (Y) may be used as a compatibilizer or diluent. Specifically, polypropylene glycol (A), a urethanization catalyst, and (meth)acrylate (Y) are charged and stirred until uniform. Thereafter, the temperature is raised as necessary, and the polyisocyanate (B) or the homogeneous mixture of the polyisocyanate (B) and the (meth)acrylate (Y) is added dropwise for reaction.

In the case of [Method 3], the polyisocyanate (B) is added dropwise to a large amount of polypropylene glycol (A) for reaction, so that the isocyanate groups of the polyisocyanate (B) are urethanized with the hydroxyl groups of the polypropylene glycol (A). . When the polypropylene glycol (A) is a diol and the polyisocyanate (B) is a diisocyanate, schematically speaking, a diol of type ABA having hydroxyl groups at both ends is by-produced, and furthermore, 2 mol The polyisocyanate (B) (diisocyanate) of reacts, and when schematically written, a compound having isocyanate groups at both ends of BABABAB type is by-produced, and the same reaction is repeated, Schematically, a large amount of a compound having the following structure may be produced as a by-product.
B-[A-B] _n -A-B (n=an integer of 1 or more)

When a large amount of by-products are produced, the acrylic density of the urethane (meth)acrylate obtained by reacting the urethane prepolymer and (meth)acrylate (C) becomes low, so that the cured product cannot obtain sufficient crosslink density. and the hardness of the cured product is lowered.

Although the by-product described in [Method 3] may be produced in [Method 2], the amount tends to be small. Moreover, in the case of [Method 2], the resulting urethane prepolymer tends to have a low viscosity.

Accordingly, [Method 1] and [Method 2] are preferably used, and [Method 1] is particularly preferably used, in order to obtain the desired urethane prepolymer in good yield.

In any method, when forming a urethane prepolymer by reacting polypropylene glycol (A) and polyisocyanate (B), it is preferable to carry out the reaction until all hydroxyl groups in the reaction solution are urethanized.

The end point of the reaction is when the isocyanate group concentration in the reaction solution is measured, and when all the hydroxyl groups charged in the system are below the isocyanate group concentration when urethanized, or when the isocyanate group concentration stops changing. can be confirmed by

The molar ratio of the hydroxyl groups of the polypropylene glycol (A) and the isocyanate groups of the polyisocyanate (B) is not particularly limited. 1 to 1.8 mol, more preferably 1.2 to 1.6 mol can be used.

When a urethane prepolymer and (meth)acrylate (C) are reacted to produce the desired urethane (meth)acrylate (X), if a large amount of unreacted isocyanate groups remain, the urethane (meth)acrylate Problems such as gelation and poor curing of the coating film may occur. To avoid these drawbacks, an alcohol (D) may be used in addition to the (meth)acrylate (C) in the reaction.

In order to avoid these problems, in the reaction, the number of moles of hydroxyl groups in (meth)acrylate (C) is excessive with respect to the number of moles of isocyanate groups in the urethane prepolymer, and It is necessary to continue the reaction until the residual isocyanate group concentration of reaches 0.05% by weight or less. In the above reaction, the number of moles of hydroxyl groups in (meth)acrylate (C) is 1.0 to 1.2 moles, preferably 1.0 to 1.0 moles, per 1 mole of isocyanate groups in the urethane prepolymer. It can be 1.1 mol. When alcohol (D) is used, the total number of moles of hydroxyl groups of (meth)acrylate (C) and alcohol (D) is preferably within the above range.

In the method for producing urethane (meth)acrylate (X), it is preferable to carry out in the presence of a polymerization inhibitor such as dibutylhydroxytoluene, hydroquinone, hydroquinone monomethyl ether, phenothiazine, etc. for the purpose of preventing polymerization. The amount of these polymerization inhibitors added is not particularly limited, but is preferably, for example, 1 to 10000 ppm (by weight), more preferably 100 to 5000 ppm, and still more preferably 200 to 1000 ppm. If the amount of the polymerization inhibitor added is less than 1 ppm relative to the urethane (meth)acrylate (X), a sufficient polymerization inhibition effect may not be obtained, and if it exceeds 10,000 ppm, the physical properties of the reaction product may be adversely affected. be.

The production method of the present invention is preferably carried out in a molecular oxygen-containing gas atmosphere. The oxygen concentration is appropriately selected in consideration of safety.

In the production method of the present invention, a catalyst (urethanization catalyst) may be used in order to obtain a sufficient reaction rate. Dibutyltin dilaurate, tin octylate, tin chloride, and the like can be used as the catalyst, but dibutyltin dilaurate is preferred in terms of reaction rate. The amount of these catalysts added is not particularly limited, but is preferably 1 to 3000 ppm (by weight), more preferably 10 to 1000 ppm, relative to the obtained urethane (meth)acrylate (X). If the amount of catalyst added is less than 1 ppm, a sufficient reaction rate may not be obtained, and if the amount is more than 3000 ppm, various physical properties of the product may be adversely affected, such as a decrease in light resistance.

The production method of the present invention can be carried out in the presence of a known volatile organic solvent. The volatile organic solvent can be distilled off under reduced pressure after the production of urethane (meth)acrylate (X). Alternatively, the volatile organic solvent remaining in the active energy ray-curable composition can be removed by applying pressure to the transparent substrate (drying). Note that the volatile organic solvent includes, for example, an organic solvent whose boiling point does not exceed 200° C. at 1.0 atmospheric pressure.

However, for systems that require hermetic curing, it is preferable to prepare the active energy ray-curable composition without the use of volatile organic solvents. In other words, it is preferable that the production method of the present invention does not contain a volatile organic solvent. For the same reason, the active energy ray-curable composition of the present invention preferably does not substantially contain a volatile organic solvent. Here, "substantially free" means that the proportion of active energy ray-curable composition is, for example, 1% by weight or less, preferably 0.1% by weight or less. , 0.01% by weight or less.

Although the reaction temperature in the production method of the present invention is not particularly limited, it is preferably carried out at 130°C or lower, more preferably 30 to 100°C, for example. When the temperature is lower than 30°C, a practically sufficient reaction rate may not be obtained, and when the temperature is higher than 130°C, the double bonds may be cross-linked by thermal radical polymerization, resulting in gelation.

In the production method of the present invention, when forming a urethane prepolymer, the reaction is allowed to proceed until the concentration of isocyanate groups in the reaction solution is equal to or less than the concentration of isocyanate groups remaining when all the hydroxyl groups subjected to the reaction are urethanized. to form a urethane prepolymer. The residual isocyanate group concentration can be analyzed by gas chromatography, titration method, or the like.

When producing urethane (meth)acrylate (X) from a urethane prepolymer, the concentration of isocyanate groups in the reaction solution is generally adjusted to 0.5% by weight or less of residual isocyanate groups. The residual isocyanate group concentration is analyzed by gas chromatography, titration, or the like.

<Active energy ray-curable composition>
The active energy ray-curable composition of the present invention is characterized by containing urethane (meth)acrylate (X) and a photopolymerization initiator (Z). The active energy ray-curable composition of the present invention may further contain a monofunctional (meth)acrylate (Y).

[Photoinitiator (Z)]
The photopolymerization initiator (Z) may vary depending on the type of active energy ray and the type of urethane (meth)acrylate (X), and is not particularly limited. 2-methyl-1-phenylpropan-1-one, diethoxyacetophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2- Hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propane-1, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin phenyl ether, benzyl dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, Acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone , isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, methylphenylglyoxy rate, benzyl, camphorquinone, and the like. In addition, a photoinitiator (Z) may be used individually by 1 type, and may use 2 or more types together.

The amount of the photopolymerization initiator (Z) used is not particularly limited, but for example, it is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 20 parts by weight based on 100 parts by weight of the total resin content of the active energy ray-curable composition. is 1 to 5 parts by weight. If the amount of photopolymerization initiator (Z) used is less than 0.1 parts by weight, there is a risk of curing failure. Odor derived from the photopolymerization initiator may remain from the coating film. In addition, the "resin component" means a curable resin contained in the active energy ray-curable composition, for example, urethane (meth)acrylate (X), monofunctional (meth)acrylate (Y), refers to polyfunctional (meth)acrylates, etc. Note that the photopolymerization initiator (Z) and the solvent do not correspond to the resin component.

[Monofunctional (meth)acrylate (Y)]
The active energy ray-curable composition of the present invention contains a monofunctional (meth)acrylate (Y), thereby adjusting the viscosity and increasing the Tg of the cured coating film in producing the urethane (meth)acrylate (X). The adjustment is performed accurately, and effects such as prevention of increase in viscosity, appearance of the resin, suppression of by-products, transparency of the cured product, heat resistance, and the like are exhibited. In addition, a monofunctional (meth)acrylate refers to a (meth)acrylate having one (meth)acryloyl group in the molecule.

As described above, (meth)acrylate (Y) may be used as a compatibilizer when forming urethane (meth)acrylate (X) (especially urethane prepolymer). By using (meth)acrylate (Y) as a compatibilizer, raw materials (for example, polypropylene glycol (A) and polyisocyanate (B)) can be compatibilized. In addition, the viscosity of the reaction solution may increase during the formation of urethane (meth)acrylate (X), and it may be used as a so-called diluent to mitigate the increase in viscosity. Furthermore, by using it when forming urethane (meth)acrylate (X), the work of adding (meth)acrylate (Y) to urethane (meth)acrylate (X) can be omitted, resulting in work efficiency. improves.

The amount of (meth)acrylate (Y) is not particularly limited. %, more preferably 4 to 96% by weight.

(Meth) acrylate (Y) is not particularly limited, for example, methyl (meth) acrylate, ethyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, dicyclopentenyl (meth) acrylate, n- Butyl (meth)acrylate, β-carboxyethyl (meth)acrylate, isobornyl (meth)acrylate, octyl/decyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl acrylate, isobutyl (meth)acrylate, tert-butyl (meth) acrylate, isodecyl (meth) acrylate, n-lauryl (meth) acrylate, n-stearyl (meth) acrylate, cyclohexyl (meth) acrylate, other alkyl (meth) acrylates, 2-hydroxyethyl (meth) acrylate, 2 -hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like, but n-octyl (meth)acrylate, isobornyl (meth)acrylate and octyl/decyl (meth)acrylate are preferred, and n-octyl ( A meth)acrylate (normal octyl (meth)acrylate) is particularly preferred. In addition, monofunctional (meth)acrylate (Y) may be used individually by 1 type, and may use 2 or more types together.

Commercially available (meth)acrylates (Y) may be used. Co., Ltd., isobornyl acrylate), product name "ODA-N" (manufactured by Daicel Ornex Co., Ltd., octyl/decyl acrylate), product name "NOA" (manufactured by Osaka Organic Chemical Co., Ltd., normal octyl acrylate ) and the like.

The active energy ray-curable composition of the present invention may further contain resins other than urethane (meth)acrylate (X) and monofunctional (meth)acrylate (Y) (for example, polyfunctional (meth)acrylate) or , various additives and solvents can be blended.

Polyfunctional (meth)acrylate is a compound having two or more (meth)acryloyl groups, and is not particularly limited as long as it is other than urethane (meth)acrylate (X). Compounds having two or more (meth)acryloyl groups in the molecule, such as acrylate, trimethylolpropane triacrylate, and tricyclodecanedimethanol diacrylate, can be mentioned. The content of the bifunctional or higher (meth)acrylate is not particularly limited, but is preferably, for example, 0.1 to 50 parts by weight, more preferably 1 to 30 parts by weight, more preferably 5 to 20 parts by weight.

Examples of additives include fillers, dyes and pigments, leveling agents, ultraviolet absorbers, light stabilizers, antifoaming agents, dispersants, and thixotropy-imparting agents. Although the amount of these additives to be added is not particularly limited, it is preferably, for example, 0 to 10 parts by weight, more preferably 0.1 part by weight, with respect to 100 parts by weight of the total resin content of the active energy ray-curable composition. 05 to 5 parts by weight.

As the solvent, for example, the volatile organic solvent described in the manufacturing method of the present invention can be used.

The active energy ray-curable composition of the present invention can be used as an interlayer filler (interlayer-filling curable composition), and can also be used as a pressure-sensitive adhesive composition or a coating agent composition, particularly an optical member or optical film. It can be used as a composition for pressure-sensitive adhesives and a composition for coating agents used in.

<Cured product>
The cured product of the present invention preferably has a surface hardness (A hardness) measured using a type A durometer based on JIS K 6253 of 70 or less, more preferably 10 to 68, and still more preferably 20. ~65. The cured product for hardness measurement is not particularly limited. For example, the hardness may be measured using a cured product produced by the method described in Examples.

<Laminate>
The laminate of the present invention includes a cured product layer of the active energy ray-curable composition between a first transparent substrate selected from glass and plastic and a second transparent substrate selected from glass and plastic. It is not particularly limited as long as it has a laminate. Preferably, the active energy ray-curable composition is applied onto a first transparent substrate to form a resin layer, a second transparent substrate is adhered onto the resin layer, and then the transparent substrate is applied. For example, by irradiating active energy rays such as ultraviolet rays or electron beams through the material, the active energy ray-curable composition is cured in an extremely short time to form a cured product layer to obtain a laminate. can be done. FIG. 1 shows one mode of the laminate.

[Transparent substrate]
As the transparent substrate, a plastic substrate such as a transparent plastic film can be used in addition to a glass substrate such as a transparent glass plate.

As the plastic substrate, it is possible to use an existing transparent material, and it is not particularly limited. Examples include polyester resins such as polyethylene naphthalate and polybutylene terephthalate, acrylic resins, and polycarbonate resins. Among these, polycarbonate resins and acrylic resins are particularly preferably used.

[Method of applying, injecting, and curing to a transparent substrate]
When the active energy ray-curable composition of the present invention is applied to a transparent substrate (for example, a glass substrate such as a glass plate or a plastic substrate such as a plastic film), the coating method is not particularly limited. method, airless spray method, air spray method, roll coating method, bar coating method, gravure method and the like can be used. Among these, the roll coating method is most preferably used from the viewpoint of beauty, cost, workability and the like. The coating may be performed by a so-called in-line coating method performed during the manufacturing process of the plastic film or the like, or may be a so-called offline coating method in which coating is performed on an already manufactured transparent base material in a separate process. From the viewpoint of production efficiency, offline coating is preferred. Also, when injecting, it is preferable to use a cartridge in order to prevent the generation of air bubbles.

Although the thickness of the cured product layer in the laminate of the present invention is not particularly limited, it is, for example, preferably 30 to 300 μm, more preferably 50 to 200 μm. When the layer thickness exceeds 300 μm, the amount of the resin composition to be applied becomes large, which tends to increase the cost and reduce the uniformity of the film thickness. On the other hand, when the thickness is less than 30 μm, there is a tendency that the flexible properties of the curable resin cannot be exhibited.

A light source for ultraviolet irradiation is not particularly limited, but for example, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, or the like is used. The irradiation time varies depending on the type of light source, the distance between the light source and the coated surface, and other conditions, but it is several tens of seconds at the longest, and usually several seconds. Usually, an irradiation source with a lamp output of about 80 to 300 W/cm is used. In the case of electron beam irradiation, it is preferable to use an electron beam having energy in the range of 50 to 1000 KeV and to set the dose to 2 to 5 Mrad. After the active energy ray irradiation, heating may be performed as necessary to promote curing.

EXAMPLES The present invention will be described in more detail below based on Synthesis Examples and Examples, but the present invention is not limited to these Examples.

Synthesis examples and comparative synthesis examples are described below. Unless otherwise specified, "ppm" and "% by weight" in the concentration notation are concentrations based on the theoretically obtained urethane (meth)acrylate. Also, the method for measuring the isocyanate group concentration, the method for measuring the viscosity, and the method for measuring the weight average molecular weight will be described.

The polyols, polyisocyanates, and hydroxyl group-containing (meth)acrylates used in Synthesis Examples and Comparative Synthesis Examples are described below. A method for determining the primary hydroxyl group ratio of the PPG-based polyol component will also be described.

[Polyol]
(PPG-based polyol component)
"FF2202" Product name: Primepol FF2202 Sanyo Chemical Industries, Ltd. Compound name: polypropylene glycol, Mw: 1992.9, hydroxyl value: 56.3 mgKOH/g Primary hydroxyl group ratio: 65 mol%, no ethylene oxide modification "PP2000" Product name: Sannics PP2000 Sanyo Chemical Industries, Ltd. Compound name: Polypropylene glycol, Mw 2028.9, hydroxyl value 55.3 mgKOH/g Primary hydroxyl group ratio: 100 mol% modified with ethylene oxide "PP4000" product Name: Sannics PP4000 Sanyo Chemical Industries, Ltd. Compound name: Polypropylene glycol, Mw 4155.5, hydroxyl value 27.0 mgKOH/g Primary hydroxyl group ratio: 100 mol% Modified with ethylene oxide “PT2001” Product name: San Nicks PT2001 Sanyo Chemical Industries, Ltd. Compound name: Polypropylene glycol, Mw 1964.9, hydroxyl value 57.1 mgKOH/g Primary hydroxyl group ratio: 100 mol% Ethylene oxide modified "PN2002" Product name: Sannics PN2002 Sanyo Kasei Kogyo Co., Ltd. Compound name: polypropylene glycol, Mw 2021.6, hydroxyl value 55.5 mgKOH/g Primary hydroxyl group ratio: 100 mol% Modified with ethylene oxide (PTMG-based polyol)
“PTMG2000” Product name: PTMG2000 manufactured by Mitsubishi Chemical Corporation Compound name: Polytetramethylene ether glycol, Mw 1965, hydroxyl value 57.1 mgKOH/g
(PC-based polyol)
“T-5652” Product name: DURANOL T-5652 Asahi Kasei Chemical Co., Ltd. Compound name: polycarbonate polyol, Mw: 2007, hydroxyl value 55.9 mgKOH/g
(PE-based polyol)
“Priplast 3199” Product name: Priplast 3199, manufactured by Croda Japan Compound name: Polyester polyol, Mw 2000, hydroxyl value 56.1 mgKOH/g
(others)
“TMP” Product name: Trimethylolpropane (TMP) Mw 134, manufactured by Mitsubishi Gas Chemical Co., Ltd., white solid “BEPD” Product name: Butylethylpropanediol, manufactured by KH Neochem [polyisocyanate]
“IPDI” Product name “VESTANAT IPDI” Evonik Co., Ltd. Compound name: isophorone diisocyanate “HDI” Product name: HDI Nippon Polyurethane Co., Ltd. Compound name: Hexamethylene diisocyanate “HMDI” Product name “HMDI” Sumika Bayer ( Co., Ltd. Compound name: Dicyclohexylmethane 4,4′-diisocyanate “TMHDI” Product name “TMHDI” Evonik Co., Ltd. Compound name: 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene Mixture with diisocyanate [hydroxy group-containing (meth)acrylate]
“HEA” Product name “β-HEA 2-hydroxyethyl acrylate” manufactured by Nippon Shokubai Co., Ltd. Compound name: 2-hydroxyethyl acrylate “HPA” Product name “2-hydroxypropyl acrylate” manufactured by Nippon Shokubai Co., Ltd. Compound Name: Hydroxypropyl acrylate [monool]
“2-EH” Product name “2-EH” Sankyo Chemical Co., Ltd. Compound name: 2-ethylhexyl alcohol [monofunctional (meth)acrylate]
“NOA” Product name “NOAA” Manufactured by Osaka Organic Chemical Co., Ltd. Compound name: normal octyl acrylate “IBOA” Product name “IBOA” Manufactured by Kyoei Co., Ltd. Compound name: isobornyl acrylate

(Synthesis example 1)
A separable flask equipped with a thermometer and stirrer was charged with 326.3 g of FF2202, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, it was cooled to 50° C. and 54.5 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

The completion of the reaction means that the isocyanate group concentration in the reaction solution is the remaining isocyanate group concentration when all the hydroxyl groups subjected to the reaction are urethanized (hereinafter sometimes referred to as "theoretical end point isocyanate group concentration") or less. I confirmed that it was. In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (1.81% by weight), the next operation was performed.

Then, 19.2 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (X-1). The molar ratio of FF2202, IPDI and HEA used in this reaction was 2.0:3.0:2.02.

(Synthesis example 2)
A separable flask equipped with a thermometer and stirrer was charged with 345.5 g of FF2202, 800 ppm of dibutylhydroxytoluene (BHT). The internal temperature was brought to 70° C., and the system was homogenized by stirring for 1 hour, then cooled to 50° C., and 45.7 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (0.91% by weight), the next operation was performed.

After that, 8.8 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated to obtain urethane (meth)acrylate (X-2). The molar ratio of FF2202, IPDI and HEA used in this reaction was 4.5:5.5:2.02.

(Synthesis Example 3)
A separable flask equipped with a thermometer and a stirrer was charged with 340.3 g of FF2202, 2.2 g of trimethylolpropane (TMP), and 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, it was cooled to 50° C. and 49.7 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (0.81% by weight), the next operation was performed.

After that, 7.8 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated to obtain urethane (meth)acrylate (X-3). The molar ratio of FF2202, TMP, IPDI and HEA used in this reaction was 5.0:0.5:6.75:2.02.

(Synthesis Example 4)
A separable flask equipped with a thermometer and stirrer was charged with 335.5 g of FF2202, 2.7 g of TMP, and 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 52.2 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (0.88% by weight), the next operation was performed.

After that, 9.6 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated to obtain urethane (meth)acrylate (X-4). The molar ratio of FF2202, TMP, IPDI and HEA used in this reaction was 4.0:0.5:5.75:2.02.

(Synthesis Example 5)
A separable flask equipped with a thermometer and stirrer was charged with 335.5 g of FF2202, 2.7 g of TMP, and 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 52.2 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (0.88% by weight), the next operation was performed.

Then 1.6 g of 2-ethylhexyl acrylate (2-EH) was charged. Furthermore, after the internal temperature was raised to 70°C and stirred for 1 hour, 8.2 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated. ) Acrylate (X-5) was obtained. The molar ratio of FF2202, TMP, IPDI, 2-EH and HEA used in this reaction was 4.0:0.5:5.75:0.3:1.72.

(Synthesis Example 6)
A separable flask equipped with a thermometer and stirrer was charged with 253.1 g of FF2202, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 32.0 g of hexamethylene diisocyanate (HDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (1.87% by weight), the next operation was performed.

After that, 14.9 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated to obtain urethane (meth)acrylate (X-6). The molar ratio of FF2202, HDI and HEA used in this reaction was 2.0:3.0:2.02.

(Synthesis Example 7)
A separable flask equipped with a thermometer and stirrer was charged with 238.9 g of FF2202, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, it was cooled to 50° C. and 47.1 g of dicyclohexylmethane 4,4′-diisocyanate (HMDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (1.76% by weight), the next operation was performed.

After that, 14.0 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated to obtain urethane (meth)acrylate (X-7). The molar ratio of FF2202, HMDI and HEA used in this reaction was 2.0:3.0:2.02.

(Synthesis Example 8)
A separable flask equipped with a thermometer and stirrer was charged with 246.5 g of FF2202, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70°C and the system was homogenized by stirring for 1 hour, it was cooled to 50°C and 39.0 g of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexa A mixture with methylene diisocyanate (TMHDI) was charged. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (1.82% by weight), the next operation was performed.

After that, 14.5 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by weight or less, the reaction was terminated to obtain urethane (meth)acrylate (X-8). The molar ratio of FF2202, TMHDI and HEA used in this reaction was 2.0:3.0:2.02.

(Synthesis Example 9)
A separable flask equipped with a thermometer and stirrer was charged with 243.3 g of FF2202, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, it was cooled to 50° C. and 40.7 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was equal to or lower than the theoretical end-point isocyanate group concentration (1.81% by weight), the next operation was performed.

After that, 16.0 g of 2-hydroxypropyl acrylate (HPA) was added, the reaction was terminated after confirming that the isocyanate group concentration was 0.05% by weight or less, and urethane (meth) acrylate (X-9 ). The molar ratio of FF2202, IPDI and HPA used in this reaction was 2.0:3.0:2.02.

(Comparative Synthesis Example 1)
A separable flask equipped with a thermometer and stirrer was charged with 420 g of PTMG2000, 333.3 g (40% by weight) of isobornyl acrylate (IBOA), and 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 63.3 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 0.73% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 16.7 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-1). The molar ratio of PTMG2000, IPDI and HEA used in this reaction was 3.0:4.0:2.02.

(Comparative Synthesis Example 2)
A separable flask equipped with a thermometer and stirrer was charged with 289.9 g DURANOL T-5652, 46.52 g BEPD, 214.29 g butyl acetate, 800 ppm dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 128.3 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 1.8% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 35.19 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-2). The molar ratio of DURANOL T-5652, BEPD, IPDI and HEA used in this reaction was 1.0:2.0:4.0:2.02.

(Comparative Synthesis Example 3)
A separable flask equipped with a thermometer and stirrer was charged with 421.2 g of Priplast 3199, 214.3 g (30 wt % min) of NOA, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 62.3 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 0.85% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 16.4 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-3). The molar ratio of Priplast 3199, IPDI and HEA used in this reaction was 3.0:4.0:2.02.

(Comparative Synthesis Example 4)
A separable flask equipped with a thermometer and stirrer was charged with 429.1 g of PP2000, 800 ppm of dibutylhydroxytoluene (BHT). The internal temperature was brought to 70° C., and the system was homogenized by stirring for 1 hour, then cooled to 50° C., and 58.6 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 0.91% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 12.4 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-4). The molar ratio of PP2000, IPDI and HEA used in this reaction was 4.0:5.0:2.02.

(Comparative Synthesis Example 5)
A separable flask equipped with a thermometer and stirrer was charged with 458.8 g of PP4000, 800 ppm dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, it was cooled to 50° C. and 32.6 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 0.63% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 8.6 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-5). The molar ratio of PP4000, IPDI and HEA used in this reaction was 3.0:4.0:2.02.

(Comparative Synthesis Example 6)
A separable flask equipped with a thermometer and stirrer was charged with 395.1 g of PT2001, 800 ppm of dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the system was homogenized by stirring for 1 hour, the system was cooled to 50° C. and 77.6 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 1.83% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 27.3 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-6). The molar ratio of PT2000, IPDI and HEA used in this reaction was 2.0:3.0:2.02.

(Comparative Synthesis Example 7)
A separable flask equipped with a thermometer and stirrer was charged with 408.1 g of PN2002, 800 ppm dibutylhydroxytoluene (BHT). After the internal temperature was brought to 70° C. and the inside of the system was homogenized by stirring for 1 hour, it was cooled to 50° C. and 68.0 g of isophorone diisocyanate (IPDI) was added. After homogenizing the system, 100 ppm of dibutyltin dilaurate (DBTDL) was added and stirred for 1 hour (the reaction temperature rose slightly during this time). Thereafter, the temperature was raised to 70°C while stirring was continued, and the reaction was continued at 70°C.

In this example, after confirming that the isocyanate group concentration in the reaction solution was 1.80% by weight or less at the theoretical end point isocyanate group concentration, the next operation was performed.

After that, 23.9 g of HEA was added, and after confirming that the isocyanate group concentration was 0.05% by concentration or less, the reaction was terminated to obtain urethane (meth)acrylate (CX-7). The molar ratio of PN2002, IPDI and HEA used in this reaction was 2.0:3.0:2.02.

[Measurement of isocyanate group concentration]
The isocyanate group concentration was measured as follows. The measurement was performed in a 100 mL glass flask under stirring with a stirrer.

(Blank value measurement)
To 15 mL of THF, add 15 mL of a THF solution of dibutylamine (0.1 N), and add 3 drops of bromophenol blue (1% methanol diluted solution) to color it blue, after which the normality is 0.1 N was titrated with an aqueous HCl solution. The amount of HCl aqueous solution titrated at the time when discoloration was observed was defined as V _b (mL).

(Measurement of actual isocyanate group concentration)
A sample W _s (g) was weighed, dissolved in 15 mL of THF, and 15 mL of a THF solution of dibutylamine (0.1N) was added. After confirming that the solution was dissolved, 3 drops of bromophenol blue (1% methanol diluted solution) were added to color the solution blue, followed by titration with an HCl aqueous solution having a normality of 0.1N. The titration amount of the HCl aqueous solution at the time when discoloration was observed was defined as V _s (mL).

The isocyanate group concentration in the sample was calculated by the following formula.
Isocyanate group concentration (% by weight) = (V _b - V _s ) x 1.005 x 0.42/W _s

[Measurement of viscosity]
The viscosity of the urethane (meth)acrylate was measured at 60° C. using an E-type viscometer (Toki Sangyo, Model TV-25), and the results are shown in Tables 1 and 2.

[Measurement of weight average molecular weight]
The weight-average molecular weight of the urethane (meth)acrylate was determined by GPC (gel permeation gas chromatography) under the following measurement conditions based on standard polystyrene, and the results are shown in Tables 1 and 2. Weight-average molecular weights in Tables 1 and 2 are shown in two significant digits.
Equipment used: TOSO HLC-8220GPC
Pump: DP-8020
Detector: RI-8020
Column type: Super HZM-M, Super HZ4000, Super HZ3000, Super HZ2000
Solvent: Tetrahydrofuran phase Flow rate: 1 mL/min Column internal pressure: 5.0 MPa
Column temperature: 40°C
Sample injection volume: 10 μL
Sample concentration: 0.2 mg/mL

[Method for calculating primary hydroxyl group ratio of polypropylene glycol]
(Sample preparation)
30 mg of polypropylene glycol was placed in a screw tube, and 0.5 mL of deuterated chloroform and 0.1 mL of trifluoroacetic anhydride were added and dissolved. By this treatment, the terminal hydroxyl group of polypropylene glycol reacts with trifluoroacetic anhydride to form a trifluoroacetate. As a result, in ¹ H-NMR measurement, a signal derived from a methylene group to which a primary hydroxyl group is bonded is observed at around 4.3 ppm, and a signal derived from a methine group to which a secondary hydroxyl group is bonded is observed at around 5.2 ppm. It will happen. The resulting solution was transferred to an NMR test tube with an inner diameter of 5 mm to prepare a sample.

( ¹ H-NMR measurement equipment and conditions)
¹ H-NMR spectra were measured using the following equipment and conditions.
Measuring device: trade name “JNM-ECA500NMR” (manufactured by JEOL Ltd.)
Solvent: deuterated chloroform Number of accumulations: 1800 Measurement temperature: 25°C

(Calculation method of primary hydroxyl group ratio)
The primary hydroxyl group ratio is calculated by the following formula.
Primary hydroxyl group ratio (mol%) = [p / (p + 2 x q)] x 100
(p: integrated value of signal derived from methylene group to which primary hydroxyl group is bonded near 4.3 ppm q: integrated value of signal derived from methine group to which secondary hydroxyl group is bonded near 5.2 ppm)

Examples and comparative examples are described below.

[Preparation of active energy ray-curable composition]
3 parts by weight of Irg184 (compound name 1 -Hydroxycyclohexylphenyl ketone, manufactured by BASF Japan Ltd.) was added to prepare an active energy ray-curable composition.

[Measurement of A hardness of cured product]
On a glass plate (dimensions: 2 x 100 x 200 mm), a square frame was made with silicon rubber (inner dimensions: 7 x 40 x 40 mm), and the preheated active energy ray-curable material was placed in the frame. The composition was added slowly so as not to generate air bubbles as much as possible. When air bubbles were conspicuous, they were removed by placing in an oven at 80°C. After that, it was heated at 80° C., and when the surface became smooth, it was irradiated with ultraviolet rays under the following conditions. FIG. 2 is a top view of the test piece A. FIG.

(Ultraviolet irradiation conditions)
Irradiation intensity: 120 W/cm
Irradiation distance: 10cm
Conveyor speed: 3.5 m/min Irradiation times: 5 times

Using an automatic constant pressure loader (GS-610, manufactured by Teclock Co., Ltd.), the A hardness of the test piece A was measured according to JIS K 6253, and the results are shown in the A hardness column of Table 3. The load at the time of measurement was 500 g, and the load descending speed was 9 mm/s.

[Evaluation of heat resistance of cured product]
The glass laminate (specimen B) was stored under the following heat-resistant conditions, and changes in the shape of the specimen B were observed.

(Preparation of test piece B)
0.2 g (±0.005 g) of the active energy ray-curable composition was accurately weighed and put on the center of a glass plate (thickness 1 mm, 5 cm square). Further, a glass plate having the same shape was placed thereon, and the resin layer was spread in a circular shape (diameter of 4 cm) to obtain a glass laminate. Thereafter, using a high-pressure mercury lamp (manufactured by Eye Graphics Co., Ltd.), the glass surface of the glass laminate was irradiated with ultraviolet rays under the following conditions to obtain a test piece B. FIG. 3A is a top view of the glass laminate, and FIG. 3B is a side view of the glass laminate.

(Ultraviolet irradiation conditions)
Irradiation intensity: 120 W/cm
Irradiation distance: 10cm
Conveyor speed: 5m/min Irradiation times: 8 times (4 times on each side)

(Storage under high temperature conditions)
Using a small environmental tester (product name SH-641, manufactured by ESPEC Co., Ltd.), test piece B was stored at a temperature of 95° C. for 1000 hours.

[Evaluation of heat resistance of cured product (shape change)]
The presence or absence of shape change of the test piece B after storage under high temperature conditions was visually measured and evaluated according to the following criteria.

If no change in shape (warpage, wrinkles, misalignment of the glass plate, etc.) can be visually observed, the heat resistance is considered to be good from the viewpoint of shape, and "○" is indicated in the heat resistance column of Table 3. On the other hand, when a change in shape was confirmed by visual observation, the heat resistance was considered to be poor from the viewpoint of shape, and "x" was entered in the heat resistance column of Table 3.

It was revealed that the cured product obtained by curing the curable composition of the present invention has high heat resistance, that is, has the property of not changing shape during the heat resistance test (Examples 1 to 9 ). On the other hand, it has become clear that a composition containing urethane (meth)acrylate obtained by using a polyol other than polypropylene glycol such as polytetramethylene ether glycol has poor flexibility and heat resistance as a cured product. (Comparative Examples 1 to 3). Furthermore, it has been clarified that a composition containing urethane (meth)acrylate obtained by addition of polypropylene glycol to ethylene oxide has poor heat resistance as a cured product, and undergoes shape change during the above heat resistance test. (Comparative Examples 4 to 7).

By incorporating the urethane (meth)acrylate of the present invention into the active energy ray-curable composition, it is possible to impart good flexibility and heat resistance to the cured product. In addition, the active energy ray-curable composition of the present invention exhibits good flexibility and heat resistance in its cured product. Therefore, the urethane (meth)acrylate of the present invention and the active energy ray-curable composition containing the same are filled between transparent substrates of displays used in personal computers, car navigation systems, televisions, mobile phones (smartphones, etc.), tablets, etc. By curing the resin, it is possible to prevent light scattering at the interface between the air and the transparent substrate, and to obtain a laminate that is less prone to change in hue and shape during the heat resistance test. In particular, it is useful even in applications where the use environment required is severe.

DESCRIPTION OF SYMBOLS 1 Cured material layer of active energy ray-curable composition 2 Transparent substrate 3 Transparent substrate 4 Silicon rubber 11 Resin 21 Glass plate 31 Resin 41 Glass plate

Claims (6)

A urethane (meth)acrylate containing polypropylene glycol (A), polyisocyanate (B), and hydroxyl group-containing (meth)acrylate (C) as structural units,
The polypropylene glycol (A) is a polypropylene glycol having a ratio of primary hydroxyl groups in terminal hydroxyl groups of 50 to 65 mol% (excluding ethylene oxide adducts of polypropylene glycol),
The urethane (meth)acrylate is a reaction product of a urethane prepolymer and the hydroxyl group-containing (meth)acrylate (C),
The urethane prepolymer is a reaction product of only polypropylene glycol (A) and polyisocyanate (B), or
Selected from the group consisting of polypropylene glycol (A), polyalkylene glycols other than polypropylene glycol (A), polyolefin polyols, hydrogenated polyolefin polyols, polyester polyols, trimethylolpropane, pentaerythritol, glycerin, and butylethylpropanediol at least one and a reactant of only the polyisocyanate (B),
In the reactant related to the urethane prepolymer, the molar ratio of the isocyanate groups of the polyisocyanate (B) to 1 mol of the hydroxyl groups of the polypropylene glycol (A) is 1.05 to 1.8 mol,
A urethane (meth)acrylate characterized by having a weight average molecular weight (Mw) of 8,000 to 500,000 . The urethane (meth)acrylate according to claim 1, wherein the polypropylene glycol (A) has a weight average molecular weight of 1,500 or more. An active energy ray-curable composition comprising the urethane (meth)acrylate according to claim 1 or 2 and a photopolymerization initiator. The active energy ray-curable composition according to claim 3, which is for interlayer filling. A cured product of the active energy ray-curable composition according to claim 3 or 4. Lamination having a cured product layer of the active energy ray-curable composition according to claim 5 between a first transparent substrate selected from glass and plastic and a second transparent substrate selected from glass and plastic body.

Images