WO2018021351A1

WO2018021351A1 - Method for forming easily-peeled protective resin thin film, and composition for forming easily-peeled protective resin thin film

Info

Publication number: WO2018021351A1
Application number: PCT/JP2017/026930
Authority: WO
Inventors: 佐藤　哲夫
Original assignee: 日産化学工業株式会社
Priority date: 2016-07-26
Filing date: 2017-07-25
Publication date: 2018-02-01
Also published as: TW201817824A; JPWO2018021351A1

Abstract

An easily-peeled protective resin thin film is formed by performing: a step in which a composition for forming the easily-peeled protective resin thin film is prepared which includes a urethane (meth)acrylate compound, a (meth)acrylate including at least a monofunctional (meth)acrylate, and either a radical polymerization initiator which does not have a hydroxyl group at a molecule terminal, or a radical polymerization initiator which has a hydroxyl group at a molecule terminal and a hindered structure; and a step in which the composition for forming the easily-peeled protective resin thin film is applied to a glass substrate to form the easily-peeled protective resin thin film.

Description

Method for forming easy-peelable protective resin thin film and easy-peelable protective resin thin film forming composition

The present invention relates to a method for forming an easily peelable protective resin thin film and an easily peelable protective resin thin film forming composition.

In order to temporarily protect the surface of an article (hereinafter also referred to as “applied object”) from abrasion and corrosion, a film is formed by applying to the surface, and the applied object is damaged when the necessary period has passed. A paint that can be peeled off without being generally called strippable paint.

As this strippable paint, as a composition for forming a temporary protective coating film on the surface of an object to be coated, a copolymer of (meth) acrylic acid and (meth) acrylic acid ester can be polymerized. A photocurable resin composition comprising an unsaturated compound having a double bond, for example, an acrylic acid adduct of phenyl glycidyl ether, and a radical curing photopolymerization initiator (hereinafter also referred to as “radical polymerization initiator”). It has been proposed (see, for example, Patent Documents 1 to 3).

Such a photo-curable resin composition is cured by light irradiation and / or heating for a short time (about 1 to 5 minutes) after coating to form a tough film, thereby improving workability. In addition, since it can be prepared without using an organic solvent, an effect of suppressing erosion of the surface of the coated body is also expected.

By the way, when the object to be coated is a glass substrate such as soda glass, the adhesive strength is such that it does not peel off from the object to be coated at the time of coating and can be easily peeled off from the object to be coated by hand after a necessary period of time has passed. There is a need for strippable paints having:

However, although many proposals have been made to use a photocurable resin composition containing a resin component and a radical polymerization initiator as an adhesive for an object to be coated which is a glass substrate (see, for example, Patent Documents 4 to 9). ), It has not been proposed as a strippable paint with excellent peelability.

Japanese Patent Laid-Open No. 04-41190 JP 2005-15594 A Japanese Patent Laid-Open No. 05-301935 JP 2012-251136 A Japanese Patent Laid-Open No. 10-25453 International Publication No. 2010/140360 JP 2000-191710 A JP 2008-7694 A JP 2008-106345 A

The present invention has been proposed in view of the above circumstances, and provides a method for forming an easily peelable protective resin thin film excellent in peelability suitable as a strippable paint and an easily peelable protective resin thin film forming composition. The purpose is to do.

Therefore, the present inventor focused on the radical polymerization initiator of the photocurable resin composition in order to achieve the above object, and conducted extensive studies to develop a strippable paint excellent in peelability. It came to acquire the knowledge of 1) and (2).

(1) When a radical polymerization initiator having no hydroxyl group at the molecular end (for example, IRGACURE (registered trademark) 907 or IRGACURE (registered trademark) 379EG) is used, the adhesion to glass decreases.
(2) Even when a radical polymerization initiator having a hydroxyl group at the molecular terminal has a hindered structure (steric hindrance structure) or the like (for example, IRGACURE (registered trademark) 184), adhesion to glass Decreases.

And this inventor makes a urethane (meth) acrylate compound (meth) acrylate containing a monofunctional (meth) acrylate of a predetermined ratio at least or a monofunctional (meth) acrylate of a predetermined ratio and a bifunctional or higher (meta) By mixing with acrylate, a radical polymerization initiator having no hydroxyl group at the molecular terminal or a radical polymerization initiator having a hydroxyl group at the molecular terminal and having a hindered structure, an easily peelable protective resin thin film forming composition is obtained. It has been found that the composition can be prepared uniformly and easily. Furthermore, the present inventor obtained a cured product from the easily peelable protective resin thin film forming composition, and the cured product was not peeled off from the glass substrate as the coated body at the time of coating, and the necessary period passed. The present invention was completed by finding that it has an adhesive force that can be easily peeled from the substrate later by hand.

That is, the present invention
1. Urethane (meth) acrylate compound, (meth) acrylate containing at least monofunctional (meth) acrylate, radical polymerization initiator having no hydroxyl group at the molecular end or radical polymerization initiator having a hydroxyl group at the molecular end and a hindered structure A step of preparing an easily peelable protective resin thin film forming composition, and a step of applying the easily peelable protective resin thin film forming composition on a glass substrate to form an easily peelable protective resin thin film; A method for forming an easily peelable protective resin thin film characterized by comprising:
2. The radical polymerization initiator having no hydroxyl group at the molecular end is diacetyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, thioxanthone, 2,4-diethylthioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4, 4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, acetophenone, p-dimethylaminoacetophenone, α, α-dimethoxy-α-acetoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone P-methoxyacetophenone, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 1- (2-methyl-4-methylthiophenyl) -2-morpholino-1-propyl Panone, α, α-dimethoxy-α- (4-morpholinomethylthiophenyl) acetophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-dimethylamino-1- ( 4-morpholinophenyl) -2- (p-tolylmethyl) butan-1-one, anthraquinone, 1,4-naphthoquinone, phenacyl chloride, tribromomethylphenylsulfone, tris (trichloromethyl) -s-triazine, [1, 2′-bisimidazole] -3,3 ′, 4,4′-tetraphenyl, [1,2′-bisimidazole] -1,2′-dichlorophenyl-3,3 ′, 4,4′-tetraphenyl, Di-tert-butyl peroxide, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, p-dimethylamino Ethyl benzoate, tert-butyl (3,5,5-trimethylhexanoyl) peroxide, tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxyoctanoate, tert-butyl peroxyneodecanoate, peroxyisobutyric acid tert-butyl, lauroyl peroxide, tert-amyl peroxypivalate, tert-butyl peroxypivalate, dicumyl peroxide, benzoyl peroxide, potassium persulfate, ammonium persulfate, 2,2'-azobis (2-methylpropion) Acid) dimethyl, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-butanenitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2- (tert-butylazo)- 2-cyanopropane, 2, '-Azobis (N, N'-dimethyleneisobutylamidine) dichloride, 2,2'-azobis (2-amidinopropane) dichloride, 2,2'-azobis (N, N-dimethyleneisobutyramide), 2,2 '-Azobis (isobutyramide) dihydrate; hydrogen peroxide, alkyl peroxide, peroxide ester or percarbonate with iron salt, first titanium salt, zinc formaldehyde sulfoxylate, sodium formaldehyde sulfoxylate or reduction Mixtures with sugars; mixtures of persulfuric acid, perboric acid or perchloric acid alkali metal salts or ammonium perchloric acid with bisulfite alkali metal salts or reducing sugars; persulfate alkali metal salts and benzenephosphonic acid Or any one selected from the group consisting of mixtures with reducing sugars, or a mixture of two or more. The method forming one of the easily peelable protective resin thin film characterized,
3. The method for forming an easily peelable protective resin thin film according to 1, wherein the radical polymerization initiator having a hydroxyl group at the molecular terminal and having a hindered structure is 1-hydroxycyclohexyl = phenyl = ketone,
4). The easily peelable protective resin thin film according to any one of 1 to 3, wherein the urethane (meth) acrylate compound is a urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as a main skeleton. Forming method,
5. 4. The method for forming an easily peelable protective resin thin film according to any one of 1 to 4, wherein the content of the monofunctional (meth) acrylate is 50% by mass or more based on the total amount of the (meth) acrylate ,
6). The method for forming an easily peelable protective resin thin film according to any one of 1 to 5, wherein the (meth) acrylate comprises the monofunctional (meth) acrylate and a bifunctional or higher (meth) acrylate,
7). The method for forming an easily peelable protective resin thin film according to any one of 1 to 6, wherein the monofunctional (meth) acrylate includes a monofunctional (meth) acrylate having a cyclic structure,
8). The easily peelable protective resin thin film according to any one of 1 to 7, wherein the content of the urethane (meth) acrylate compound in the easily peelable protective resin thin film forming composition is less than 80% by mass. Forming method,
9. The easily peelable protective resin thin film according to any one of 1 to 8, wherein the urethane (meth) acrylate compound content in the easily peelable protective resin thin film forming composition is 10% by mass or more. Forming method,
10. The method for forming an easily peelable protective resin thin film according to any one of 1 to 9, wherein the easily peelable protective resin thin film is a cured product of the easily peelable protective resin thin film forming composition,
11. A urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as a main skeleton, a (meth) acrylate containing at least a monofunctional (meth) acrylate, and a radical polymerization initiator or molecule having no hydroxyl group at the molecular end An easily peelable protective resin thin film forming composition comprising a radical polymerization initiator having a hydroxyl group at a terminal and a hindered structure is provided.

By using the method for forming an easily peelable protective resin thin film of the present invention, a uniform easily peelable protective resin thin film forming composition can be easily prepared, and the prepared composition can be peeled from a glass substrate. An excellent easily peelable protective resin thin film can be formed. That is, the resin thin film does not peel from the glass substrate even when immersed in warm water, for example, but has an adhesive force that can be easily peeled from the glass substrate by hand. Since the resin thin film has such characteristics, in order to temporarily protect the surface of the substrate from corrosion, abrasion, dirt, etc. when polishing or cutting the glass substrate or storing the glass substrate. It can be used as a strippable paint.

The method for forming an easily peelable protective resin thin film according to an embodiment of the present invention includes a urethane (meth) acrylate compound, a (meth) acrylate containing at least a monofunctional (meth) acrylate, and a radical having no hydroxyl group at the molecular end. A step of preparing a resin film forming composition for easily peelable protection comprising a polymerization initiator or a radical polymerization initiator having a hydroxyl group at the molecular terminal and a hindered structure; and a resin thin film forming composition for easily peelable protective glass And a step of forming an easily peelable protective resin thin film on a substrate.

First, a process for preparing an easily peelable protective resin thin film forming composition (hereinafter also referred to as “composition”) will be described. The composition of the present embodiment includes a urethane (meth) acrylate compound, a monofunctional (meth) acrylate, a bifunctional or higher (meth) acrylate as necessary, a radical polymerization initiator having no hydroxyl group at the molecular end, or a molecular end. It can be prepared by mixing each component such as a radical polymerization initiator having a hydroxyl group and a hindered structure.

For example, a predetermined amount of each component is put into a SUS preparation tank having a stirring blade, and stirred at room temperature (approximately 25 ° C.) or under heating until uniform. Moreover, you may filter the composition obtained by mixing each component with a mesh, a membrane filter, etc. as needed. The composition thus obtained is liquid and is also called a resin liquid. In addition, when a certain component which comprises the composition of this embodiment has the function of another component, it is necessary to determine the quantity of each component in consideration of the point.

Next, the raw material of each component of the composition of this embodiment will be described. This composition contains a urethane (meth) acrylate compound, and preferably contains a urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as a main skeleton.

The urethane (meth) acrylate compound having a polycaprolactone skeleton as a main skeleton is not particularly limited as long as it has a polycaprolactone skeleton that is a ring-opening polymer of caprolactone as a main skeleton, and a commercially available product may be used. Alternatively, those manufactured by a known method may be used. As a urethane (meth) acrylate compound having such a polycaprolactone skeleton, for example, a polycaprolactone polyol (such as Placel Cell series manufactured by Daicel Corporation), a polyisocyanate compound, and a (meth) acrylate compound having a hydroxyl group A reactant can be used. Examples of commercially available products include Art Resin UN-352 (manufactured by Negami Kogyo Co., Ltd.), but are not limited thereto.

The urethane (meth) acrylate compound having a polytetramethylene glycol skeleton as a main skeleton is not particularly limited, and a commercially available product may be used or a product produced by a known method may be used. As a urethane (meth) acrylate compound having such a polytetramethylene glycol skeleton, for example, a reaction product of a bifunctional polytetramethylene glycol, a polyisocyanate compound, and a (meth) acrylate compound having a hydroxyl group is used. be able to. Examples of commercially available products include, but are not limited to, Shikou (registered trademark) UV-2750B, UV-7000B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and the like.

The weight average molecular weight of the urethane (meth) acrylate compound is usually about 500 to 100,000, but from the viewpoint of toughness of the resulting easily peelable protective resin thin film (hereinafter also referred to as “resin thin film”). , Preferably it is 1,000 or more, More preferably, it is 2,000 or more. Further, from the viewpoint of securing the coatability by suppressing an excessive increase in the viscosity of the composition of the present embodiment, it is preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 8,000 or less. More preferably, it is 5,000 or less. In addition, a weight average molecular weight is a polystyrene conversion measured value by gel permeation chromatography (GPC) (hereinafter the same).

The content of the urethane (meth) acrylate compound with respect to the entire composition (resin liquid) of this embodiment is preferably 10% by mass or more and less than 80% by mass, or 10% by mass or more and less than 70% by mass, or 20% by mass or more and 70% by mass. It is less than mass%, or 30 mass% or more and less than 60 mass%. By setting the content of the compound to less than 80% by mass, the viscosity of the composition is prevented from excessively rising and not only the coating property of the composition is easily maintained, but also relatively ethylenic. The amount of the unsaturated monomer is increased, and the adjustment of the adhesion force to the glass substrate is facilitated. On the other hand, it becomes easy to ensure the peelability of the resin thin film of this embodiment by making content of the said compound into 10 mass% or more.

The composition of the present embodiment contains at least a monofunctional (meth) acrylate as an ethylenically unsaturated monomer for the purpose of improving the adhesion of the resulting resin thin film and reducing the viscosity of the composition (meth). Contains acrylate. The (meth) acrylate may contain a monofunctional (meth) acrylate and a bifunctional or higher (meth) acrylate. The ethylenically unsaturated monomer is a compound having at least one ethylenically unsaturated double bond.

As the monofunctional (meth) acrylate, an alkyl monofunctional (meth) acrylate is preferable, and an alkyl monofunctional (meth) acrylate having 6 or more carbon atoms in the alkyl group is more preferable.

The alkyl group may be linear, branched, or cyclic. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl A linear or branched alkyl group having 1 to 20 carbon atoms such as a group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group and n-decyl group; Group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, bicyclobutyl group, bicyclopentyl group, bicyclohexyl group, bicycloheptyl group, bicyclooctyl group, bicyclononyl group, bicyclo Examples thereof include cyclic alkyl groups having 3 to 20 carbon atoms such as decyl group.

Further, as the monofunctional (meth) acrylate, those having a ring structure (also referred to as “cyclic structure”) in the molecule are preferable from the viewpoint of improving the toughness of the resin thin film of the present embodiment. A polymer of (meth) acrylate having a ring structure has a glass transition temperature (Tg) higher than that having a linear substituent, and a hard film is easily obtained. On the other hand, a substituent having a ring structure has a smaller free volume than a linear substituent and is difficult to inhibit the entanglement of (meth) acrylate main chains necessary for the toughness of the resin thin film. Therefore, a resin thin film containing a monofunctional (meth) acrylate having a ring structure is considered to be a hard but tough film.

Specific examples of the monofunctional alkyl (meth) acrylate having 6 or more carbon atoms in the alkyl group include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 6- Methylheptyl (meth) acrylate, nonyl (meth) acrylate, 7-methyloctyl (meth) acrylate, decyl (meth) acrylate, 8-methylnonyl (meth) acrylate, lauryl (meth) acrylate, 10-methylundecyl (meth) Acrylate, stearyl (meth) acrylate, 16-methylheptadecyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl Meth) acrylate.

Specific examples of (meth) acrylates other than monofunctional alkyl (meth) acrylates having 6 or more carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, and phenoxyethyl (meth). Acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, n-butyl (meth) acrylate, benzyl (meth) acrylate, ethylene oxide modified (n = 2) phenol (meth) acrylate, propylene oxide modified (n = 2. 5) Nonylphenol (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, furfuryl (meth) acrylate, carbitol (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) acrylate 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (Meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate and the like can be mentioned. Among them, those not containing a hydroxyl group are preferable, and the molecular weight is preferably about 100 to 300.

Of these, 8-methylnonyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, 16-methylheptadecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isobornyl (meth) acrylate are preferable.

Monofunctional (meth) acrylates can be used singly or in combination of two or more.

Examples of the bifunctional or higher functional (meth) acrylate include bifunctional (meth) acrylate and trifunctional or higher functional (meth) acrylate.

Examples of the bifunctional (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. , Dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythrine Ritol di (meth) acrylate, ethylene glycol diglycidyl ether (meth) acrylic acid adduct, diethylene glycol diglycidyl ether (meth) acrylic acid adduct, phthalic acid diglycidyl ester (meth) acrylic acid adduct, hydroxypivalic acid modified neopentyl Examples include glycol di (meth) acrylate.

Examples of the trifunctional or higher functional (meth) acrylate include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol. Examples include hexa (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and glycerin polyglycidyl ether (meth) acrylic acid adduct.

Among these, bifunctional (meth) acrylate or trifunctional or higher (meth) acrylate is preferable, and bifunctional (meth) acrylate is more preferable.

Bifunctional or higher (meth) acrylates can be used singly or in combination of two or more.

The content of (meth) acrylate, that is, monofunctional (meth) acrylate and bifunctional or higher (meth) acrylate with respect to the entire composition of the present embodiment is usually from the viewpoint of reducing the viscosity of the composition and improving workability. It is 10% by mass or more, preferably 20% by mass or more, and more preferably 30% by mass or more, preferably from the viewpoint of controlling the toughness and adhesion of the resin thin film (cured product) of the composition to be described later. It is 35% by mass or more, more preferably 40% by mass or more.

When using bifunctional or higher functional (meth) acrylate in combination with monofunctional (meth) acrylate, from the viewpoint of ensuring the toughness of the resin thin film to the extent that it can be used as a strippable paint, the content of monofunctional (meth) acrylate, More than the content of the bifunctional or higher (meth) acrylate. When the content of the bifunctional or higher (meth) acrylate is higher than the content of the monofunctional (meth) acrylate, the resin thin film becomes hard, but becomes brittle and the toughness decreases.

The content ratio between the content of monofunctional (meth) acrylate (W _s ) and the content of bifunctional or higher (meth) acrylate (W _m ) is [W _m / (W _s + W _m )] × 100 <50 The mass% (in other words, [W _s / (W _s + W _m )] × 100 ≧ 50 mass%) is satisfied. From the viewpoint of the toughness of the resin thin film, the content is preferably 40% by mass or less, more preferably 30% by mass or less, and from the viewpoint of improving the water resistance of the resulting resin thin film, preferably 1% by mass or more. More preferably, it is 5 mass% or more, More preferably, it is 10 mass% or more, More preferably, it is 15 mass% or more.

The composition of the present embodiment has a polarity that can be copolymerized with the above-mentioned monofunctional (meth) acrylate and bifunctional or higher (meth) acrylate for the purpose of improving the adhesion of the resin thin film to the base material, heat resistance, etc. A group-containing monomer may be included.

Examples of the polar group-containing monomer include (meth) acrylic acid, (meth) acrylamide, (meth) acryloylmorpholine, (meth) acrylonitrile and the like.

When the composition of this embodiment contains a polar group-containing monomer, the content does not exceed the total content of monofunctional (meth) acrylate and bifunctional or higher (meth) acrylate. If the ratio of the polar group-containing monomer is increased, the water resistance of the resulting resin thin film is lowered, and as a result, peelability and the like may be lowered.

The composition of the present embodiment includes a radical polymerization initiator such as a radiation radical polymerization initiator and a thermal radical polymerization initiator, and these radical polymerization initiators have no hydroxyl groups at the molecular ends. An initiator or a radical polymerization initiator having a hydroxyl group at the molecular end and a hindered structure can be applied.

Here, the radical polymerization initiator having no hydroxyl group at the molecular terminal is, for example, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one represented by the following formula (1), Like 2-dimethylamino-1- (4-morpholinophenyl) -2- (p-tolylmethyl) butan-1-one represented by the following formula (2), it does not have a hydroxyl group in the structure. On the other hand, a radical polymerization initiator having a hydroxyl group at the molecular terminal and having a hindered structure is a compound in which the hydroxyl group in the structure is tert-butyl, such as 1-hydroxycyclohexyl = phenyl ketone represented by the following formula (3). It is adjacent to a bulky substituent such as a group or a cyclohexyl group, and the reactivity of the hydroxyl group is reduced.

The composition of this embodiment can impart excellent peelability to the glass substrate by including a radical polymerization initiator having no hydroxyl group at the molecular end or a radical polymerization initiator having a hydroxyl group at the molecular end and a hindered structure. . In addition, although the mechanism by which excellent peelability is not inhibited by using these radical polymerization initiators is not clarified, it is considered that the glass substrate and the composition of the present embodiment do not form hydrogen bonds. .

Specific examples of the radical polymerization initiator that is a radiation radical polymerization initiator and does not have a hydroxyl group at the molecular end include α-diketones such as diacetyl; acyloins such as benzoin; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl Acyloin ethers such as ether; thioxanthone, 2,4-diethylthioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, etc. Benzophenones; acetophenone, p-dimethylaminoacetophenone, α, α-dimethoxy-α-acetoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, p-methoxyacetophenone, 2-methyl-1- ( -Methylthiophenyl) -2-morpholinopropan-1-one, 1- (2-methyl-4-methylthiophenyl) -2-morpholino-1-propanone, α, α-dimethoxy-α- (4-morpholinomethylthiophenyl) Acetophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-dimethylamino-1- (4-morpholinophenyl) -2- (p-tolylmethyl) butane-1- Acetophenones such as ON; quinones such as anthraquinone and 1,4-naphthoquinone; halogen compounds such as phenacyl chloride, tribromomethylphenylsulfone, tris (trichloromethyl) -s-triazine; [1,2'-bisimidazole ] -3,3 ′, 4,4′-tetraphenyl, [1,2′-bisimidazole] ] -1,2'-dichlorophenyl-3,3 ', 4,4'-tetraphenyl and other bisimidazoles; di-tert-butyl peroxide and other peroxides; diphenyl (2,4,6-trimethylbenzoyl) ) Acylphosphine oxides such as phosphine oxide; p-dimethylaminobenzoate such as ethyl p-dimethylaminobenzoate.

Commercially available radical polymerization initiators that are radiation radical polymerization initiators that do not have a hydroxyl group at the molecular end include IRGACURE (registered trademark) 651, 907, 369, 379EG, 819, TPO, and MBF. (Above, manufactured by BASF Japan Co., Ltd.), KAYACURE DETX-S, EPA (above, manufactured by Nippon Kayaku Co., Ltd.), and the like, but are not limited thereto.

Examples of radiation radical polymerization initiators having a hydroxyl group at the molecular end and having a hindered structure include 1-hydroxycyclohexyl = phenyl = ketone and the like.

IRGACURE (registered trademark) 184 (manufactured by BASF Japan Ltd.) and the like can be mentioned as a commercial product of a radical polymerization initiator which is a radiation radical polymerization initiator and has a hydroxyl group at the molecular end and a hindered structure. However, it is not limited to these.

Examples of thermal radical polymerization initiators include hydrogen peroxides, azo compounds, and redox initiators.

Specific examples of radical polymerization initiators that are hydrogen peroxides and do not have a hydroxyl group at the molecular end include tert-butyl (3,5,5-trimethylhexanoyl) peroxide, tert-butyl peroxyacetate, peroxybenzoic acid tert-butyl, tert-butyl peroxyoctanoate, tert-butyl peroxyneodecanoate, tert-butyl peroxyisobutyrate, lauroyl peroxide, tert-amyl peroxypivalate, tert-butyl peroxypivalate, dicumyl peroxide, Examples include benzoyl oxide, potassium persulfate, and ammonium persulfate.

Specific examples of the radical polymerization initiator that is an azo compound and does not have a hydroxyl group at the molecular end include 2,2′-azobis (2-methylpropionic acid) dimethyl and 2,2′-azobis (isobutyronitrile). 2,2′-azobis (2-butanenitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2- (tert-butylazo) -2-cyanopropane, 2,2′-azobis (N, N ′) -Dimethyleneisobutylamidine) dichloride, 2,2'-azobis (2-amidinopropane) dichloride, 2,2'-azobis (N, N-dimethyleneisobutyramide), 2,2'-azobis (isobutylamide) A hydrate etc. are mentioned.

The radical polymerization initiator that is a redox initiator and does not have a hydroxyl group at the molecular end includes hydrogen peroxide, alkyl peroxide, peroxide ester, percarbonate, etc., iron salt, first titanium salt, zinc formaldehyde A mixture with a sulfoxylate, sodium formaldehyde sulfoxylate, etc. is mentioned. Moreover, the mixture of persulfuric acid, perboric acid, the alkali metal salt of perchloric acid, the ammonium salt of perchloric acid, etc. and alkali metal bisulfite, such as sodium metabisulfite, is mentioned. Furthermore, a mixture of an alkali metal persulfate and other similar acids such as arylphosphonic acid such as benzenephosphonic acid can be exemplified.

Commercial products of radical polymerization initiators that are thermal radical polymerization initiators and do not have a hydroxyl group at the molecular end include Perhexa (registered trademark) HC (manufactured by NOF Corporation), MAIB (manufactured by Otsuka Chemical Co., Ltd.) Is mentioned.

The radical polymerization initiator having no hydroxyl group at the molecular terminal or the radical polymerization initiator having a hydroxyl group at the molecular terminal and having a hindered structure may be used singly or in combination of two or more. Moreover, the composition of this embodiment may contain a compound having hydrogen donating properties such as mercaptobenzothiazole and mercaptobenzoxazole, and a radiosensitizer together with a radical polymerization initiator. In addition, mercaptobenzothiazole and mercaptobenzoxazole do not have a hydroxyl group in their chemical structural formula.

In addition, when the composition of this embodiment contains a radical polymerization initiator having a hydroxyl group at the molecular end and not having a hindered structure, it is not preferable because the peelability to the glass substrate is inhibited.

On the other hand, a radical polymerization initiator having a hydroxyl group at the molecular end and not having a hindered structure is, for example, 2-hydroxy-1- (4- (2-hydroxyethoxy) phenyl) -2- represented by the following formula (4): Like methylpropan-1-one, the substituent adjacent to the hydroxyl group is a small substituent such as a hydrogen atom or a methyl group, and the reactivity of the hydroxyl group is not limited.

Specific examples of the radical polymerization initiator having a hydroxyl group at the molecular terminal and not having a hindered structure include the above-mentioned 2-hydroxy-1- (4- (2-hydroxyethoxy) phenyl) -2-methylpropan-1-one In addition, 2-hydroxy-2-methyl-1-phenylpropan-1-one, tert-butyl hydroperoxide, cumene hydroperoxide, 4,4′-azobis (4-pentanoic acid), 2,2′-azobis ( 2-methyl-N- (1,1-bis (hydroxymethyl) -2-hydroxyethyl) propionamide), 2,2′-azobis (2-methyl-N- (1,1-bis (hydroxymethyl) ethyl) ) Propionamide), 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) propionamide) and the like.

Moreover, as a commercial item of the radical polymerization initiator which has a hydroxyl group in a molecular terminal and does not have a hindered structure, IRGACURE (registered trademark) 2959, 127, DAROCUR (registered trademark) 1173 (above, manufactured by BASF Japan Ltd.) Etc.

The content of the radical polymerization initiator with respect to the entire composition of the present embodiment is a urethane (meth) acrylate compound, (meth) acrylate, from the viewpoint of suppressing the effect of radical deactivation due to oxygen, ensuring storage stability, and the like. (Monofunctional (meth) acrylate or monofunctional (meth) acrylate and bifunctional or higher (meth) acrylate)) The total amount is 100 parts by mass, preferably 0.1 to 50 parts by mass, more preferably 1 part by mass To 30 parts by mass, and more preferably 2 to 30 parts by mass.

The composition of this embodiment may contain a solvent. As the solvent, a solvent that can uniformly dissolve each component of the composition and does not react with these components is used.

Specific examples of such solvents include carbonates such as ethylene carbonate and propylene carbonate; fatty acids such as caproic acid and caprylic acid; alcohols such as 1-octanol, 1-nonanol and benzyl alcohol; ethylene glycol monoethyl ether Alkyl ethers of polyhydric alcohols such as diethylene glycol monomethyl ether and propylene glycol monomethyl ether (PGME); alkyl ether acetates of polyhydric alcohols such as ethylene glycol ethyl ether acetate and propylene glycol monomethyl ether acetate (PGMEA); phenyl cellosolve acetate Aryl ether acetates of polyhydric alcohols such as: ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-hydroxy Propionic acid ethyl, ethyl lactate, esters such as γ- butyrolactone; ketols diacetone alcohol and the like. In addition, a solvent can be used individually by 1 type or in combination of 2 or more types.

When the composition of the present embodiment contains a solvent, the content thereof is about 5% by mass to 30% by mass with respect to the entire composition.

The composition of the present embodiment may contain a surfactant for the purpose of improving applicability, defoaming property, leveling property and the like.

Specific examples of the surfactant include BM-1000, BM-1100 (above, manufactured by BM Chemie), MegaFace (registered trademark) F142D, F172, F173, F183, F183 (above, DIC Corporation) ), Fluorad FC-135, FC-170C, FC-430, FC-431 (above, manufactured by 3M Japan), Surflon S-112, S-113, S-131, S-141, S-145 (above, manufactured by AGC Seimi Chemical Co., Ltd.), SH-28PA, -190, -193, SZ-6032, SF-8428 (above, manufactured by Toray Dow Corning Co., Ltd.) ) And the like, and commercially available fluorine-based surfactants and silicone-based surfactants.

When the composition of this embodiment contains a surfactant, the content is preferably 5% by mass or less of the entire composition from the viewpoint of preventing precipitation from the resin thin film.

The composition of the present embodiment may contain a thermal polymerization inhibitor.

Specific examples of thermal polymerization inhibitors include pyrogallol, benzoquinone, hydroquinone, methylene blue, tert-butylcatechol, hydroquinone monobenzyl ether, methylhydroquinone, amyloxyhydroquinone, n-butylphenol, phenol, hydroquinone monopropyl ether, 4,4 ′ -(1-methylethylidene) bis (2-methylphenol), 4,4 '-(1-methylethylidene) bis (2,6-dimethylphenol), 4,4'-(1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bisphenol, 4,4 ′, 4 ″ -ethylidenetris (2-methylphenol), 4,4 ′, 4 ″ -ethylidenetrisphenol, 1 , 1,3-Tris (2,5-dimethyl-4-hydro Shifeniru) -3-phenylpropane, and the like.

When the composition of the present embodiment contains a thermal polymerization inhibitor, the content thereof is 5% by mass or less of the entire composition from the viewpoint of preventing an excessive decrease in radical polymerizability and ensuring appropriate radical polymerizability. preferable.

The composition of this embodiment may contain a release agent for the purpose of improving the peeling peelability.

As the release agent, any of wax compounds, silicone compounds, and fluorine compounds can be used. Among them, silicone compounds (silicones having a siloxane bond as the main skeleton from the viewpoints of heat resistance, moisture resistance, and stability over time) Oils, emulsions, etc.) are preferred.

The release agent is available as a commercial product. Examples of such commercially available products include Shin-Etsu Silicone (registered trademark) KF-96-10CS, KF-6012, X-22-2426, X-22-164E (manufactured by Shin-Etsu Chemical Co., Ltd.), TEGO (registered trademark) RAD 2200N, 2700 (above, manufactured by Evonik Japan Co., Ltd.), BYK-333 (above, produced by Big Chemie Japan Co., Ltd.) and the like.

When the composition of this embodiment contains a release agent, the content thereof is preferably 5% by mass or less with respect to the entire composition from the viewpoint of preventing precipitation from the resin thin film.

In addition, the composition of the present embodiment may contain other components such as a leveling agent and an antifoaming agent.

Through the process of preparing the composition as described above, the easily peelable protective resin thin film forming composition according to the embodiment of the present invention is obtained. The composition of the present embodiment comprises a urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as a main skeleton, a (meth) acrylate containing at least a monofunctional (meth) acrylate, and a hydroxyl group at the molecular end. And a radical polymerization initiator having a hindered structure having a hydroxyl group at a molecular terminal. In particular, such a composition uses a urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as the main skeleton as the urethane (meth) acrylate compound, and has a hydroxyl group at the molecular end as a radical polymerization initiator. A resin film for easy-peeling protection with excellent releasability from a glass substrate, which will be described later, using a radical polymerization initiator or a radical polymerization initiator having a hydroxyl group at the molecular terminal and a hindered structure. Can be formed. In addition, since it is as having mentioned above about details, such as each component of the composition of this embodiment, its compounding ratio, description is abbreviate | omitted.

Next, the process of forming an easily peelable protective resin thin film will be described. In this step, the composition (resin liquid) obtained in the step of preparing the above-described composition is applied to a glass substrate (for example, soda glass), and cured by light irradiation and / or heating to thereby form a resin. A thin film can be formed. That is, the obtained resin thin film is made of a cured product of the composition.

Examples of the coating method of the composition (resin liquid) include, but are not limited to, spin coating, slit coating, roll coating, screen printing, applicator, and dispenser.

The film thickness of the resin thin film is preferably 5 μm to 250 μm, 5 μm to 150 μm, or 10 μm to 50 μm from the viewpoint of realizing each characteristic such as water resistance and peelability with good reproducibility.

As a method for changing the film thickness of the resin thin film, for example, there is a method of changing the concentration of solid content in the composition or changing the coating amount on the glass substrate.

The method of forming the easily peelable protective resin thin film according to the present embodiment includes a step of preparing an easily peelable protective resin thin film forming composition and a step of forming the easily peelable protective resin thin film, thereby forming glass. An easily peelable protective resin thin film can be formed on the substrate. In such a forming method, by using the radical polymerization initiator described above, the obtained easily peelable protective resin thin film is excellent in peelability to the glass substrate, and does not peel from the glass substrate when the resin thin film is formed. After the necessary period, it can be easily peeled from the glass substrate by hand. Such an easily peelable protective resin thin film is suitable as a strippable paint.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the following examples. In addition, the abbreviation used in the Example represents the following meaning.

UN-352: Polycaprolactone-based urethane acrylate [Art Resin UN-352 manufactured by Negami Kogyo Co., Ltd.]
IBXA: Isobornyl acrylate [manufactured by Tokyo Chemical Industry Co., Ltd.]
A-TMPT: trimethylolpropane triacrylate [NK Nakamura Chemical Co., Ltd. NK ester A-TMPT]
Irg. 907: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one [IRGACURE (registered trademark) 907 manufactured by BASF Japan Ltd.]
DETX-S: 2,4-diethylthioxanthone [manufactured by Nippon Kayaku Co., Ltd. KAYACURE DETX-S]
Irg. 184: 1-hydroxycyclohexyl = phenyl = ketone [IRGACURE (registered trademark) 184, manufactured by BASF Japan Ltd.]
Irg. 2959: 2-hydroxy-1- (4- (2-hydroxyethoxy) phenyl) -2-methylpropan-1-one [IRGACURE (registered trademark) 2959, manufactured by BASF Japan Ltd.]

(1) Preparation of easy-peelable protective resin film-forming composition Using UN-352 as a urethane (meth) acrylate compound having polycaprolactone as the main skeleton, the mass ratio (mass%) shown in Table 1 below is: Each raw material is weighed into a glass sample bottle, mixed with stirring using a magnetic stirrer while heating to about 50 ° C., and used for easy peel protection in Examples 1 and 2 and Comparative Example 1. Each resin thin film forming composition (hereinafter referred to as “composition”) was prepared.

UN-352 has a polycaprolactone skeleton as a main skeleton, a urethane moiety at both ends thereof, a cyclohexyl ring in the molecule, and two acrylate groups in the molecule by structural analysis. It was recognized as a thing.

(2) Preparation and evaluation of easy-peeling protective resin thin film (2-1) Preparation of easy-peeling protective resin thin film The compositions of Examples 1 and 2 and Comparative Example 1 were each placed on a glass substrate (soda glass). By using an applicator (baker applicator YBA-3 type manufactured by Yoshimitsu Seiki Co., Ltd., wet film thickness 125 μm setting), followed by UV exposure (illuminance 50 mW / cm ² , irradiation amount 500 mJ / cm ² ), An easily peelable protective resin thin film (hereinafter referred to as “cured product”) having a thickness of about 90 μm was obtained. All were easily curable, and each cured product was in close contact without naturally falling off from the glass substrate. In addition, when it was confirmed whether or not the obtained cured product could be peeled from the glass substrate by hand, all cured products could be peeled, but the cured product obtained from the compositions of Examples 1 and 2 Was easy to peel off.

(2-2) Evaluation of peelability Each of the obtained cured products was cut into strips having a length of 10 cm and a width of 3 cm without peeling from the glass substrate. A glass substrate was fixed horizontally to a testing machine, one end of a cured product cut into a strip shape was slightly peeled off, and this was held with a chuck. By moving the chuck upward at a speed of 1 cm / sec, the resistance (N) when the cured product was peeled from the glass substrate at a peeling angle of 90 ° was measured. The peel force (N / cm) was calculated by dividing the resistance force by the width (3 cm) of the cured product, and the results are shown in Table 2 below. For the measurement, a desktop precision universal testing machine Autograph AGS-500NX manufactured by Shimadzu Corporation was used.

As shown in Table 2, when the cured product obtained from the compositions of Examples 1 and 2 and the cured product obtained from the composition of Comparative Example 1 were compared, Examples 1 and 2 were more glass. The good peelability to the substrate was maintained.

That is, Example 1 is a radical polymerization initiator that does not have a hydroxyl group at the molecular terminal, and Example 2 is a radical polymerization initiator that has a hydroxyl group at the molecular terminal and has a hindered structure. Since a cured product was formed using both, the peel force from the glass substrate was as low as 0.04 N / cm in both cases. On the other hand, in Comparative Example 1, since a cured product was formed using a radical polymerization initiator having a hydroxyl group at the molecular end, the peel force from the glass substrate was a relatively high value of 0.08 N / cm. In general, the lower the peel force, the better. The practical use is likely to cause a problem when it exceeds 0.10 N / cm. Therefore, in Comparative Example 1, the high peel force may be a problem depending on the application. There is sex.

Claims

A urethane (meth) acrylate compound,
(Meth) acrylate containing at least a monofunctional (meth) acrylate;
A step of preparing an easily peelable protective resin thin film forming composition comprising a radical polymerization initiator having no hydroxyl group at a molecular end or a radical polymerization initiator having a hydroxyl group at a molecular end and a hindered structure;
And a step of applying the easily peelable protective resin thin film forming composition on a glass substrate to form an easily peelable protective resin thin film.
The radical polymerization initiator having no hydroxyl group at the molecular end is diacetyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, thioxanthone, 2,4-diethylthioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4, 4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, acetophenone, p-dimethylaminoacetophenone, α, α-dimethoxy-α-acetoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone P-methoxyacetophenone, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 1- (2-methyl-4-methylthiophenyl) -2-morpholino-1 Propanone, α, α-dimethoxy-α- (4-morpholinomethylthiophenyl) acetophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-dimethylamino-1- ( 4-morpholinophenyl) -2- (p-tolylmethyl) butan-1-one, anthraquinone, 1,4-naphthoquinone, phenacyl chloride, tribromomethylphenylsulfone, tris (trichloromethyl) -s-triazine, [1, 2′-bisimidazole] -3,3 ′, 4,4′-tetraphenyl, [1,2′-bisimidazole] -1,2′-dichlorophenyl-3,3 ′, 4,4′-tetraphenyl, Di-tert-butyl peroxide, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, p Ethyl dimethylaminobenzoate, tert-butyl (3,5,5-trimethylhexanoyl) peroxide, tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxyoctanoate, tert-butyl peroxyneodecanoate, peroxy Tert-butyl isobutyrate, lauroyl peroxide, tert-amyl peroxypivalate, tert-butyl peroxypivalate, dicumyl peroxide, benzoyl peroxide, potassium persulfate, ammonium persulfate, 2,2'-azobis (2- Dimethyl methylpropionate), 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-butanenitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2- (tert-butylazo) -2-Si Anopropane, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dichloride, 2,2'-azobis (2-amidinopropane) dichloride, 2,2'-azobis (N, N-dimethyleneisobutyramide) ), 2,2′-azobis (isobutyramide) dihydrate; hydrogen peroxide, alkyl peroxide, peroxide ester or percarbonate, iron salt, first titanium salt, zinc formaldehyde sulfoxylate, sodium formaldehyde Mixtures of sulfoxylate or reducing sugar; alkali metal salts of persulfuric acid, perboric acid or perchloric acid or ammonium salts of perchloric acid and alkali metal bisulfite or reducing sugar; alkali metal persulfate And any one selected from the group consisting of a mixture of benzenephosphonic acid or reducing sugar, or a combination of two or more. The method of forming the easily peelable protective resin thin film according to claim 1, characterized in that the combined mixture.
2. The method for forming an easily peelable protective resin thin film according to claim 1, wherein the radical polymerization initiator having a hydroxyl group at the molecular terminal and having a hindered structure is 1-hydroxycyclohexyl = phenyl = ketone.
The urethane (meth) acrylate compound according to any one of claims 1 to 3, wherein the urethane (meth) acrylate compound is a urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as a main skeleton. Of forming an easily peelable protective resin thin film.
The easy peeling according to any one of claims 1 to 4, wherein the content of the monofunctional (meth) acrylate is 50% by mass or more based on the total amount of the (meth) acrylate. Of forming a protective resin thin film.
The (meth) acrylate is the monofunctional (meth) acrylate,
The method for forming an easily peelable protective resin thin film according to any one of claims 1 to 5, comprising a bifunctional or higher functional (meth) acrylate.
The easily peelable protective resin thin film according to any one of claims 1 to 6, wherein the monofunctional (meth) acrylate includes a monofunctional (meth) acrylate having a cyclic structure. Method.
The content of the urethane (meth) acrylate compound in the resin film forming composition for easily peelable protection is less than 80% by mass, according to any one of claims 1 to 7. Of forming an easily peelable protective resin thin film.
The content of the urethane (meth) acrylate compound in the easy-peelable protective resin thin film forming composition is 10% by mass or more, wherein the content of the urethane (meth) acrylate compound is 10% by mass or more. Of forming an easily peelable protective resin thin film.
The easily peelable protective film according to any one of claims 1 to 9, wherein the easily peelable protective resin thin film is a cured product of the easily peelable protective resin thin film forming composition. Of forming a resin thin film.
A urethane (meth) acrylate compound having a polycaprolactone skeleton or a polytetramethylene glycol skeleton as a main skeleton,
(Meth) acrylate containing at least a monofunctional (meth) acrylate;
An easily peelable protective resin thin film forming composition comprising: a radical polymerization initiator having no hydroxyl group at a molecular terminal or a radical polymerization initiator having a hydroxyl group at a molecular terminal and a hindered structure.