Surface-protecting composition and surface protective film

Abstract

This surface-protecting composition includes a polymer (A) including a structural unit (a) derived from a (meth)acrylate (a) having an alkyl group as a protective group, and an acid generator (B) including at least one generator selected from a photoacid generator and a thermal acid generator. A product other than the acid after acid generation of the acid generator (B) includes one or more chemicals selected from the group consisting of gases and water-soluble compounds.

Description

Surface protection composition and surface protection film

[0001] The present invention relates to a surface protective composition and a surface protective film.

[0002] Techniques relating to surface protection films used in the manufacture of electronic devices include those described in Patent Documents 1 and 2, for example.

[0003] Patent Document 1 describes a semiconductor processing tape that is a laminate of a water-soluble film containing a polymer compound with a weight-average molecular weight of 200,000 or more and a low-molecular compound with a molecular weight of 800 or less, and a surface protection tape that protects the circuit surface of a semiconductor wafer. Patent Document 1 also describes that it is possible to provide a semiconductor processing tape that can be removed by washing with unheated water while achieving both grooving resistance and wafer adhesion.

[0004] Patent Document 2 describes a surface protection composition for protecting at least one surface of a substrate, the surface protection composition including a polymer having a hydrophilic group in the molecule and a compound that generates an acid or a base upon at least one of heating and irradiation with active energy rays. Patent Document 2 also describes that a surface protection composition can be provided for forming a protective layer that covers and protects at least one surface of a substrate in an electronic component device to be manufactured, and then is relatively easily removed upon contact with a liquid containing water.

[0005] JP 2023-043723 A International Publication No. 2023 / 195445 A

[0006] The present invention provides a surface protection composition that is water-resistant and capable of forming a water-washable protective film after at least one treatment selected from light irradiation and heating.

[0007] The present inventors conducted extensive research to solve the above-mentioned problems, and as a result, found that a surface protecting composition can form a protective film that is water-resistant and can be washed with water after at least one treatment selected from the group consisting of light irradiation and heating, by combining a polymer that includes a structural unit derived from a (meth)acrylate having an alkyl group as a protecting group with an acid generator that generates an acid in the form of one or more compounds selected from the group consisting of gases and water-soluble compounds.

[0008] That is, according to the present invention, there are provided the following surface protection composition and surface protection film.

[0009] [1] A surface-protecting composition comprising: a polymer (A) containing a structural unit (a) derived from a (meth)acrylate (a) having an alkyl group as a protecting group; and an acid generator (B) containing at least one selected from a photoacid generator and a thermal acid generator, wherein the acid generator (B) generates an acid and the non-acid product is one or more selected from the group consisting of a gas and a water-soluble compound. [2] The surface-protecting composition according to [1], wherein the acid generator (B) contains a photoacid generator. [3] The surface-protecting composition according to [1] or [2], wherein a film formed from the surface-protecting composition does not peel off from a glass plate, does not become cloudy, or does not dissolve when the following <Method 1> is performed. <Method 1> A film having a thickness of 10±5 μm formed from the surface-protecting composition is formed on a glass plate, and the glass plate and the film are then immersed in water for 10 minutes, and then the glass plate and the film are removed from the water. [4] The surface protecting composition according to any one of [1] to [3], wherein the (meth)acrylate (a) comprises an acrylate. [5] The surface protecting composition according to any one of [1] to [4], wherein the alkyl group in the (meth)acrylate (a) comprises at least one selected from the group consisting of a tert-butyl group and an isobornyl group. [6] The surface protecting composition according to any one of [1] to [5], wherein the alkyl group in the (meth)acrylate (a) comprises a tert-butyl group. [7] The surface protecting composition according to any one of [1] to [6], wherein the polymer (A) further comprises a structural unit (b) derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid, N-isopropylacrylamide, and acryloylmorpholine. [8] The surface protecting composition according to any one of [1] to [7], wherein the polymer (A) has a weight average molecular weight (Mw) of 10,000 or more and 10,000,000 or less in terms of polystyrene, as measured by gel permeation chromatography. [9] The surface protecting composition according to any one of [2] to [8], wherein the photoacid generator includes a non-ionic photoacid generator.

[10] The surface protecting composition according to [9], wherein the nonionic photoacid generator includes a nonionic photoacid generator having a diazomethane structure.

[11] The surface protecting composition according to any one of [1] to

[10] , wherein the content of the acid generator (B) is 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the polymer (A).

[12] A surface protecting film comprising the surface protecting composition according to any one of [1] to

[11] .

[0010] According to the present invention, it is possible to provide a surface protection composition that is water-resistant and capable of forming a protective film that can be washed off with water after at least one treatment selected from light irradiation and heating.

[0011] Hereinafter, embodiments of the present invention will be described. In this specification, unless otherwise specified, "A to B" indicating a range of numerical values ​​means A or more and B or less.

[0012] <Surface Protecting Composition> The surface protecting composition of this embodiment includes a polymer (A) including a structural unit (a) derived from a (meth)acrylate (a) having an alkyl group as a protecting group, and an acid generator (B) including at least one selected from a photoacid generator and a thermal acid generator, and the acid generator (B) generates products other than an acid after acid generation that include one or more compounds selected from the group consisting of gases and water-soluble compounds.

[0013] The surface-protective composition of this embodiment contains a polymer (A) containing a structural unit (a) derived from a (meth)acrylate (a) having an alkyl group as a protecting group, thereby providing a film made from the surface-protective composition with water resistance. Furthermore, since the surface-protective composition contains the polymer (A) and the acid generator (B), when the film made from the surface-protective composition is subjected to at least one treatment selected from light irradiation and heating, the acid generator (B) generates an acid, which deprotects the alkyl group of the (meth)acrylate (a) in the polymer (A). Furthermore, since the products other than the acid of the acid generator (B) include one or more selected from the group consisting of gases and water-soluble compounds, the film made from the surface-protective composition is peeled off or dissolved from the substrate, etc., and the surface-protective film can be washed with water.

[0014] (Polymer (A)) The polymer (A) in the surface protective composition of this embodiment contains a structural unit (a) derived from a (meth)acrylate (a) having an alkyl group as a protecting group. The polymer (A) contains the structural unit (a) derived from a (meth)acrylate (a), which improves the water resistance of a film made from the surface protective composition. Furthermore, the structural unit (a) derived from a (meth)acrylate (a) has an alkyl group as a protecting group, so that when the acid generator (B) generates an acid after at least one treatment selected from light irradiation and heating, the alkyl group of the polymer (A) is deprotected by the acid, and the film made from the surface protective composition is peeled off or dissolved from the substrate, etc., making it possible to wash the film with water.

[0015] The (meth)acrylate (a) in the polymer (A) preferably contains an acrylate, which can further improve the water washability of the resulting film while maintaining the water resistance.

[0016] From the viewpoint of further improving the water washability of the resulting film, the alkyl group in the (meth)acrylate (a) in the polymer (A) preferably contains at least one selected from the group consisting of a tert-butyl group and an isobornyl group, and more preferably contains a tert-butyl group. When the alkyl group in the (meth)acrylate (a) in the polymer (A) contains a tert-butyl group, the water washability of the resulting film is further improved. Specifically, when the alkyl group in the (meth)acrylate (a) in the polymer (A) contains a tert-butyl group, the acid generator (B) generates an acid by performing at least one treatment selected from light irradiation and heating, and then the acid deprotects the tert-butyl group, and butylene (CH ２ =CH-CH ２ -CH ３ Here, butylene is a gas at room temperature, so it evaporates from the membrane and does not affect the subsequent water solubility, i.e., water washability, of the membrane. This further improves the water washability of the resulting membrane.

[0017] In addition to the structural unit (a), the polymer (A) preferably further contains structural units (b) derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid, N-isopropylacrylamide, and acryloylmorpholine, more preferably from one or more monomers (b) selected from the group consisting of (meth)acrylic acid and N-isopropylacrylamide, and even more preferably from one or two monomers (b) selected from the group consisting of acrylic acid and N-isopropylacrylamide. When the polymer (A) further contains the structural unit (b), the resulting film has improved adhesion to substrates and water resistance, and the coatability of the surface protection composition is also improved. When the polymer (A) further contains the structural unit (b), the content of the structural unit (b) is preferably 40% by mass or less, more preferably 30% by mass or less, and may be 0% by mass or more, based on the total amount of the polymer (A) taken as 100% by mass. By ensuring that the content of the structural unit (b) is within the above range, the water resistance of the resulting film can be maintained while further improving the balance of film-forming properties and adhesion.

[0018] The weight average molecular weight (Mw) of the polymer (A) measured by gel permeation chromatography in terms of polystyrene is preferably 10,000 to 10,000,000, more preferably 30,000 to 5,000,000, even more preferably 50,000 to 1,800,000, even more preferably 100,000 to 1,000,000, even more preferably 120,000 to 500,000, and even more preferably 150,000 to 300,000. When the weight average molecular weight (Mw) of the polymer (A) measured by gel permeation chromatography in terms of polystyrene is within the above range, the water washability of the resulting membrane can be further improved.

[0019] The Mw / Mn calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography of the polymer (A) is preferably 2.0 or more and 300 or less, more preferably 3.0 or more and 250 or less, even more preferably 3.5 or more and 200 or less, even more preferably 4.0 or more and 100 or less, even more preferably 4.5 or more and 30 or less, and even more preferably 5.0 or more and 23 or less. When the Mw / Mn calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography of the polymer (A) is within the above range, the water washability of the obtained membrane can be further improved.

[0020] The weight average molecular weight (Mw) and Mw / Mn of the polymer (A) in terms of polystyrene, measured by gel permeation chromatography, can be adjusted by appropriately adjusting conditions such as the type of catalyst, polymerization temperature, polymerization pressure, and polymerization time in the synthesis of the polymer (A) described below.

[0021] (Method for Synthesizing Polymer (A)) The polymer (A) of this embodiment can be synthesized by an appropriate known method. For example, the polymer (A) can be obtained by polymerizing the (meth)acrylate (a) having the alkyl group and the monomer (b) described above in the presence of an appropriate known polymerization catalyst. The polymerization catalyst can be, for example, one or more selected from the group consisting of azo compounds, organic peroxides, and photopolymerization initiators. Examples of azo compounds that can be used include 2,2'-azobis(isobutyronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile). When an azo compound is used as the polymerization catalyst, the monomers can be polymerized by, for example, heating a solution containing the (meth)acrylate (a), the monomer (b), and the azo compound at 50 to 80°C for 1 hour to 20 hours. Examples of photopolymerization initiators that can be used include 1-hydroxycyclohexyl phenyl ketone and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. When a photopolymerization initiator is used as the polymerization catalyst, for example, a solution containing (meth)acrylate (a), monomer (b) and the photopolymerization initiator is irradiated with UVA light at a UV intensity of 20 to 50 mW / cm ２ The monomer can be polymerized by irradiating the solution with UV light at a temperature of about 10 to 60 minutes. As a commercially available organic peroxide, Perbutyl (registered trademark) O (manufactured by NOF Corporation) can be used.

[0022] (Acid Generator (B)) The acid generator (B) in the surface protecting composition of this embodiment includes at least one selected from a photoacid generator and a thermal acid generator, and from the viewpoint of further improving the water washability of the resulting film, the acid generator (B) preferably includes a photoacid generator.

[0023] The photoacid generator preferably includes a nonionic photoacid generator, from the viewpoint of further improving the water resistance of the resulting film and further improving the water washability of the film after at least one treatment selected from light irradiation and heating, and more preferably the nonionic photoacid generator includes a nonionic photoacid generator having a diazomethane structure.

[0024] Examples of the thermal acid generator include aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, and boron trifluoride amine complexes.

[0025] Furthermore, in order to improve the water washability of the resulting film, the acid generator (B) in the surface protection composition of this embodiment contains one or more non-acid products selected from the group consisting of gases and water-soluble compounds. Here, the non-acid products produced by the acid generator (B) after acid generation preferably have a molecular weight of 20 to 1,200, more preferably 30 to 1,000, even more preferably 50 to 800, even more preferably 100 to 500, even more preferably 150 to 350, and even more preferably 200 to 300. More preferably, the non-acid products produced by the acid generator (B) after acid generation contain a hydrophilic group. The hydrophilic group may be, for example, one or more selected from the group consisting of a hydroxy group, an amino group, a carboxyl group, a cyano group, a sulfonic acid group, a phosphate group, a sulfonyl group, and an amide group. In this embodiment, the water-soluble compound refers to a compound that has a solubility of 1% by mass or more in water at 25°C. By selecting an appropriate type of acid generator as described above as the acid generator (B), it is possible to make the product other than the acid generated by the acid generator (B) include one or more compounds selected from the group consisting of gases and water-soluble compounds.

[0026] The content of the acid generator (B) in the surface protecting composition is preferably 5 parts by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 45 parts by mass or less, even more preferably 20 parts by mass or more and 40 parts by mass or less, even more preferably 25 parts by mass or more and 40 parts by mass or less, and even more preferably 30 parts by mass or more and 35 parts by mass or less, relative to 100 parts by mass of the polymer (A). When the content of the acid generator (B) in the surface protecting composition is within the above range, the water washability of the obtained film can be further improved.

[0027] (Method for Producing the Surface Protective Composition) The method for producing the surface protective composition of this embodiment can be carried out by any known method. For example, the composition can be produced by mixing the polymer (A), acid generator (B), and solvent described above using a mixer rotor or the like until homogeneous. The solvent can be one or more selected from the group consisting of acetone, ethyl acetate, toluene, ethanol, and propylene glycol monomethyl ether acetate. Only one solvent may be used, or two or more solvents may be used in combination.

[0028] (Formation of a film from the surface protective composition) The surface protective composition of this embodiment can be formed into a film by any known method. For example, the surface protective composition can be applied to a substrate such as a silicon wafer to a film thickness of about 10 to 120 μm, and then dried to form a film. Drying conditions are preferably at a temperature of 50° C. or higher and 130° C. or lower, more preferably at a temperature of 60° C. or higher and 100° C. or lower, and for a period of preferably 1 minute to 1 hour, more preferably 3 minutes to 30 minutes.

[0029] (Method for cleaning a film made of the surface protective composition) Cleaning of a film made of the surface protective composition of this embodiment (i.e., a surface protective film) is carried out as follows. When the acid generator (B) contains a photoacid generator, it is preferable to irradiate light onto the film made of the surface protective composition of this embodiment formed on a substrate or the like. By irradiating light, the film made of the surface protective composition can be peeled off or dissolved from the substrate or the like, and water cleanability can be further improved. The light irradiation is specifically UV irradiation, and the illuminance is preferably 20 mW / cm. ２ More than 9000mW / cm ２ More preferably, the illuminance is 500 mW / cm or less. ２ More than 9000mW / cm ２ More preferably, the illuminance is 3000 mW / cm or less. ２ More than 9000mW / cm ２ More preferably, the illuminance is 5000 mW / cm or less. ２ More than 9000mW / cm ２The irradiation time is preferably 10 seconds or more and 120 seconds or less, more preferably 20 seconds or more and 100 seconds or less, and the integrated light amount is preferably 2000 mJ / cm ２ More than 300J / cm ２ or less, more preferably 100 J / cm ２ More than 300J / cm ２ More preferably, 200 J / cm or less ２ More than 300J / cm ２Hereinafter, the ultraviolet irradiation conditions are preferably 200 nm to 400 nm, more preferably 250 nm to 380 nm, in terms of wavelength. Light irradiation can be performed using, for example, LED lighting or a high-pressure mercury lamp. As an LED lighting, for example, Hololite Kaku manufactured by Pi Photonics Inc. can be used. As a high-pressure mercury lamp, for example, UVC-408 manufactured by Technovision Co., Ltd. can be used. Furthermore, when irradiating light under the above-described light irradiation conditions, it is preferable to place a film made of the surface protective composition of this embodiment formed on a substrate or the like on a black resin plate or the like. By placing it on a black resin plate, the heat generated by light irradiation is not removed, and the film made of the surface protective composition is heated simultaneously with light irradiation. This allows the film made of the surface protective composition to dissolve in water, further improving water washability. Furthermore, it is more preferable to heat the film made of the surface protective composition of this embodiment formed on a substrate or the like in addition to light irradiation. By heating in addition to light irradiation, the film made of the surface protective composition can dissolve in water, further improving water washability. From the viewpoint of further improving the dissolution rate of the film made of the surface protective composition, the heating temperature is preferably 100°C or higher and 200°C or lower, more preferably 120°C or higher and 180°C or lower, and even more preferably 140°C or higher and 160°C or lower. The heating time is preferably 1 minute or higher and 30 minutes or lower, and more preferably 2 minutes or higher and 15 minutes or lower. Light irradiation and heating may be performed simultaneously, or heating may be performed after light irradiation. When the acid generator (B) contains a thermal acid generator, it is preferable to heat the film made of the surface protective composition of this embodiment formed on a substrate or the like. The heating temperature is preferably 100°C or higher and 200°C or lower, more preferably 120°C or higher and 180°C or lower, and even more preferably 140°C or higher and 160°C or lower. The heating time is preferably 1 minute or higher and 30 minutes or lower, and more preferably 2 minutes or higher and 15 minutes or lower. When performing water washing, it is preferable to immerse the film made of the surface protective composition and the substrate or the like in water after heating, light irradiation, or heating and light irradiation.In addition, the film made of the surface protection composition can also be water-washed by subjecting it to one or more cleaning methods selected from the group consisting of jet cleaning, two-fluid cleaning, spray cleaning, shower cleaning, and ultrasonic cleaning.

[0030] After water washing under the above conditions, it is preferable that the entire film made of the surface protective composition is peeled off from the substrate, etc., and it is more preferable that the entire film made of the surface protective composition is dissolved. By completely dissolving the film made of the surface protective composition, it is possible to further prevent the film made of the surface protective composition from remaining on the substrate, etc. after water washing. In addition, it becomes easier to treat wastewater when the film made of the surface protective composition is washed with water.

[0031] The water resistance of the surface-protective composition of this embodiment is evaluated, for example, according to the following <Method 1>. <Method 1> A film of 10±5 μm thickness made of the surface-protective composition of this embodiment is formed on a glass plate, and then the glass plate and the film are immersed in water for 10 minutes. When the glass plate and the film are then removed from the water, it is preferable that the film made of the surface-protective composition does not peel off from the glass plate, does not become cloudy, or does not dissolve. This can further improve the water resistance of the film made of the surface-protective composition.

[0032] The cleaning properties of the surface protecting composition of this embodiment can be evaluated, for example, according to the following <Method 2> or <Method 3>.

[0033] <Method 2> A film having a thickness of 10±5 μm and made of the surface protection composition of this embodiment is formed on a glass plate. Then, the substrate with the film is placed on a black resin plate, and an illuminance of 7705 mW / cm is applied. ２ , irradiation time 30 seconds, cumulative light amount 230 J / cm ２Under the conditions, ultraviolet light having a wavelength of 365 nm is irradiated onto the film-side surface of the substrate. Next, the glass plate and the film are immersed in water, and the time until the entire film is peeled off from the glass plate is taken as the peeling time (minutes). When the above <Method 2> is performed, the peeling time of the surface protective composition is preferably 30 minutes or less, more preferably 25 minutes or less, even more preferably 20 minutes or less, even more preferably 15 minutes or less, and even more preferably 10 minutes or less, from the viewpoint of further improving water washability. There is no lower limit for the peeling time of the surface protective composition, but it may be, for example, 10 seconds or more, or 30 seconds or more.

[0034] <Method 3> A film having a thickness of 10±5 μm and made of the surface protection composition of this embodiment is formed on a glass plate. Then, the substrate with the film is placed on a black resin plate, and an illuminance of 7705 mW / cm is applied. ２ , irradiation time 30 seconds, cumulative light amount 230 J / cm ２ Under the conditions, ultraviolet light having a wavelength of 365 nm is irradiated onto the film-side surface of the substrate. Next, the glass plate and the film are immersed in water, and the time until the entire film dissolves in water is taken as the dissolution time (minutes). From the viewpoint of further improving water washability, the dissolution time of the surface protective composition when the above <Method 3> is performed is preferably 30 minutes or less, more preferably 20 minutes or less, even more preferably 15 minutes or less, even more preferably 10 minutes or less, even more preferably 5 minutes or less, even more preferably 2 minutes or less, and even more preferably 1 minute or less. There is no lower limit for the dissolution time of the surface protective composition, but it may be, for example, 10 seconds or more, or 20 seconds or more.

[0035] <Surface protective film> The surface protective film of this embodiment includes the surface protective composition of this embodiment. The surface protective film of this embodiment may be formed by applying the surface protective composition of this embodiment onto a substrate or the like to form a membrane, or may be formed as a film.

[0036] The surface protection film of this embodiment can be used as a surface protection film that protects the surface of electronic components and is ultimately removed in the manufacturing process of electronic devices. Examples of electronic components include semiconductor chips such as ICs, LSIs, discrete devices, light-emitting diodes, and light-receiving elements, as well as semiconductor panels, semiconductor packages, and wafers.

[0037] The thickness of the surface protective film of this embodiment is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, from the viewpoint of further improving the performance balance between water resistance and surface protectiveness, and is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less, from the viewpoint of further improving water washability.

[0038] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0039] The present invention is not limited to the above-described embodiment, and any modifications and improvements that can achieve the object of the present invention are included in the present invention.

[0040] The present embodiment will be described in detail below with reference to examples and comparative examples, but the present embodiment is not limited to the descriptions of these examples.

[0041] <Raw Materials> The raw materials used in the Examples and Comparative Examples are as follows: (Polymer (A)) ((Meth)acrylate (a) having an alkyl group (structural unit (a))) t-Butyl acrylate: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. t-Butyl methacrylate: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Isobornyl acrylate: manufactured by Tokyo Chemical Industry Co., Ltd. (Monomer (b) (structural unit (b))) N-Isopropylacrylamide Acrylic acid

[0042] (Acid Generator (B)) Non-ionic photoacid generator: Bis(tert-butylsulfonyl)diazomethane, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., WPAG-170 Sulfonium salt photoacid generator: CPI-110B, manufactured by San-Apro Co., Ltd. Iodonium salt photoacid generator: 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, manufactured by Tokyo Chemical Industry Co., Ltd.

[0043] <Synthesis of Polymer (A)> Polymer solutions for each example were synthesized according to the formulations in Table 1 and by the following method. (Preparation of Polymer Solution 1) 0.06 g of 1-hydroxycyclohexyl phenyl ketone was added to 3.0 g of t-butyl acrylate to obtain a monomer solution. This was irradiated with light for 10 minutes in a nitrogen atmosphere while stirring and ice-cooling, according to the light irradiation method described below, to obtain a polymer. Next, 12 g of acetone was added to the polymer, and the mixture was heated at 50°C for 3 hours while stirring, to obtain Polymer Solution 1 containing an acrylic polymer. A mercury-xenon lamp illumination device (LC8:L9588, manufactured by Hamamatsu Photonics KK) was used for light irradiation. The illumination intensity of the panel display was set to 23%, and irradiation was performed from a condenser lens 7 cm away from the monomer solution. The intensity of the light irradiated onto the monomer solution was measured using an illuminance meter (UV PowerPuck II, manufactured by EIT Co., Ltd.). When the illuminance meter and a mercury xenon lamp lighting device were placed at a distance of 7 cm, the UVA intensity was 28 mW / cm. ２ It was.

[0044] (Preparation of Polymer Solution 2) A monomer solution was obtained by mixing 4.0 g of t-butyl acrylate and 7.7 g of ethyl acetate. Furthermore, 0.30 g of 2,2'-azobis(isobutyronitrile) (AIBN, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 6.0 g of ethyl acetate to obtain an initiator solution. Next, 0.93 mL of the initiator solution was added to the monomer solution heated to 65°C under a nitrogen atmosphere. This was heated for 1 hour under a nitrogen atmosphere with stirring, and then 0.93 mL of the initiator solution was added again, followed by heating for an additional 7 hours. This was allowed to cool to room temperature, allowed to stand for 14 hours or more, and then heated again for 7 hours at 65°C under a nitrogen atmosphere with stirring to obtain Polymer Solution 2 containing an acrylic polymer.

[0045] (Preparation of Polymer Solution 3) 2.7 g of t-butyl acrylate and 0.80 g of N-isopropylacrylamide were mixed, and 0.07 g of 1-hydroxycyclohexyl phenyl ketone was added to obtain a monomer solution. This was irradiated with light for 15 minutes in a nitrogen atmosphere while being cooled on ice and stirred, in the same manner as for Polymer Solution 1, to obtain a polymer. 28 g of acetone was then added to the polymer, and the mixture was heated to 50°C for 3 hours while being stirred, to obtain Polymer Solution 3 containing an acrylic polymer.

[0046] (Preparation of Polymer Solution 4) 8.0 g of t-butyl acrylate, 1.5 g of acrylic acid, and 18 g of ethyl acetate were mixed to obtain a monomer solution. Furthermore, 0.30 g of 2,2'-azobis(isobutyronitrile) (AIBN, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 6.0 g of ethyl acetate to obtain an initiator solution. Next, 2.2 mL of the initiator solution was added to the monomer solution heated to 65°C under a nitrogen atmosphere. This was heated for 1 hour under a nitrogen atmosphere with stirring, and then 2.2 mL of the initiator solution was added again, followed by heating for an additional 7 hours. This was allowed to cool to room temperature, allowed to stand for 14 hours or more, and then heated again for 7 hours under a nitrogen atmosphere with stirring at 65°C to obtain Polymer Solution 4 containing an acrylic polymer.

[0047] (Preparation of Polymer Solution 5) Polymer solution 5 containing an acrylic polymer was obtained in the same manner as polymer solution 1, except that the t-butyl acrylate in the monomer solution was changed to 3.0 g of t-butyl methacrylate, the light irradiation time was changed to 30 minutes, and the amount of acetone added was changed to 9.0 g.

[0048] (Preparation of Polymer Solution 6) Polymer solution 6 containing an acrylic polymer was obtained in the same manner as polymer solution 1, except that t-butyl acrylate in the monomer solution was changed to 3.0 g of isobornyl acrylate and 12 g of acetone was changed to 9 g of toluene.

[0049] <Weight Average Molecular Weight (Mw), Number Average Molecular Weight (Mn), and Mw / Mn> The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer (A) in each example were measured by gel permeation chromatography (GPC) under the following conditions. Automatic injection device: 717plus, manufactured by Nihon Waters Pump: KP-22-13S dual pump, manufactured by Fromm Column: PLgel 10μ MIXED-B, inner diameter 7.5 mm x 300 mm (3 columns), manufactured by Agilent Technologies Differential refractive index detector: Shodex RI-101, manufactured by Resonac Corporation Column calibration: EasiCal PS-1 polystyrene, manufactured by Agilent Technologies Eluent: tetrahydrofuran for HPLC, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Column temperature: 40°C Flow rate: 1.0 mL / min Mw / Mn was calculated from the obtained values. Mw and Mw / Mn are shown in Table 1.

[0050]

[0051] <Method for manufacturing surface protection composition> The obtained polymer (A), acid generator (B), and acetone, ethyl acetate, and toluene as solvents were mixed using a mix rotor in the proportions shown in Table 2 until homogeneous, thereby obtaining a surface protection composition for each example.

[0052] <Evaluation of cleaning properties> The surface protection compositions shown in Table 2 were applied to a glass substrate (water slide glass, S7213, manufactured by Matsunami Glass Industrial Co., Ltd.) using a non-wire bar coater OSP-80-L60 (film thickness 80 μm / wet), and dried in an oven at 100°C for 5 minutes to obtain a film coated on the substrate. The thickness of the film after drying was within the range of 10±5 μm. The obtained film was subjected to light irradiation or light irradiation and heating under the following conditions A to D. (Conditions for light irradiation or light irradiation and heating) (Condition A) The substrate with the film was placed on a SUS stand, and the illuminance was 7705 mW / cm. ２ , irradiation time 30 seconds, cumulative light amount 230 J / cm ２Under the conditions, ultraviolet light with a wavelength of 365 nm was irradiated onto the film-side surface of the substrate using an LED light source (manufactured by Pi Photonics Co., Ltd., product name: Hololite Kaku). The temperature of the film surface on the SUS stand during light irradiation was measured using a radiation thermometer and found to be approximately 30°C. (Condition B) Light irradiation was carried out in the same manner as condition A, except that the film-coated substrate was placed on a black resin plate (manufactured by Oriental Giken Kogyo Co., Ltd.). The temperature of the film surface on the black resin plate during light irradiation was measured using a radiation thermometer and found to be approximately 100°C. (Condition C) Light irradiation was carried out in the same manner as condition A, except that after light irradiation, the film-coated substrate was heated on a hot plate heated to 120°C for 10 minutes. (Condition D) Light irradiation was carried out in the same manner as condition A, except that after light irradiation, the film-coated substrate was heated on a hot plate heated to 150°C for 5 minutes.

[0053] Next, the substrate and the film were immersed in water, and the time until the entire film peeled off from the substrate (peeling time (min)) or the time until the entire film dissolved in water (dissolution time (min)) was measured. Cleanability was also evaluated according to the following criteria. A or B was considered acceptable. The results are shown in Table 2. (Criteria) A: The film was completely dissolved within 10 minutes. B: The film was completely peeled off from the substrate within 10 minutes. C: Some of the film remained on the substrate within 10 minutes. D: The film neither dissolved nor peeled off within 10 minutes.

[0054] <Evaluation of Water Resistance> The surface protection composition shown in Table 2 was applied to a glass substrate (water slide glass, S7213, manufactured by Matsunami Glass Industrial Co., Ltd.) using a non-wire bar coater OSP-80-L60 (film thickness 80 μm / wet), and dried in an oven at 100°C for 5 minutes to obtain a film coated on the substrate. The thickness of the film after drying was within the range of 10±5 μm. Next, the substrate and the film were immersed in water for 10 minutes, and then removed from the water. The state of the substrate and the film was observed, and water resistance was evaluated according to the following criteria. A was considered to be acceptable. The results are shown in Table 2. (Criteria) A: The film did not dissolve and was adhered to the substrate. B: The film peeled off from the substrate. C: The film became cloudy or dissolved.

[0055]

[0056] This application claims priority based on Japanese Patent Application No. 2024-055762, filed March 29, 2024, the disclosure of which is incorporated herein in its entirety by reference.

Claims

1. A surface protection composition comprising: a polymer (A) containing a structural unit (a) derived from a (meth)acrylate (a) having an alkyl group as a protecting group; and an acid generator (B) containing at least one selected from a photoacid generator and a thermal acid generator, wherein the acid generator (B) generates an acid and the product other than the acid is one or more selected from the group consisting of a gas and a water-soluble compound.

2. The surface protecting composition according to claim 1, wherein the acid generator (B) includes a photoacid generator.

3. The surface protective composition according to claim 1 or 2, wherein a film made of the surface protective composition does not peel off from a glass plate, does not become cloudy, or does not dissolve when the following <Method 1> is carried out: <Method 1> A film made of the surface protective composition and having a thickness of 10±5 μm is formed on a glass plate, and then the glass plate and the film are immersed in water for 10 minutes, and then the glass plate and the film are removed from the water.

4. The surface protecting composition according to any one of claims 1 to 3, wherein the (meth)acrylate (a) comprises an acrylate.

5. The surface protecting composition according to any one of claims 1 to 4, wherein the alkyl group in the (meth)acrylate (a) includes at least one selected from the group consisting of a tert-butyl group and an isobornyl group.

6. The surface protecting composition according to any one of claims 1 to 5, wherein the alkyl group in the (meth)acrylate (a) includes a tert-butyl group.

7. The surface protecting composition according to any one of claims 1 to 6, wherein the polymer (A) further contains structural units (b) derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid, N-isopropylacrylamide, and acryloylmorpholine.

8. The surface protecting composition according to any one of claims 1 to 7, wherein the weight average molecular weight (Mw) of the polymer (A) measured by gel permeation chromatography in terms of polystyrene is 10,000 or more and 10,000,000 or less.

9. The surface protecting composition according to any one of claims 2 to 8, wherein the photoacid generator includes a nonionic photoacid generator.

10. The surface protecting composition according to claim 9, wherein the non-ionic photoacid generator comprises a non-ionic photoacid generator having a diazomethane structure.

11. A surface protecting composition according to any one of claims 1 to 10, wherein the content of the acid generator (B) is 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the polymer (A).

12. A surface protective film comprising the surface protective composition according to any one of claims 1 to 11.

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