JP7563100B2 - Curable composition for temporary fixing and method for temporary fixing - Google Patents

Description

The present invention relates to a curable composition for temporary fixation and a method for temporary fixation.

Curable compositions containing 2-cyanoacrylate compounds have a unique anionic polymerization property of the main component, 2-cyanoacrylate compounds, which allows them to initiate polymerization with weak anions such as traces of moisture adhering to the surface of the substrate, and to firmly bond various materials in a short time. For this reason, they are used as so-called instant adhesives in a wide range of fields, including industrial, medical, and household applications.

The curable composition containing the 2-cyanoacrylate compound has a hard cured product and excellent shear adhesive strength, but it has the disadvantage of lacking flexibility and low peel strength. In addition, the hard adhesive cured product does not deform in response to pressure and does not exhibit adhesion or re-adhesion after peeling. Therefore, it is difficult to peel and re-adhere an adherend that has been adhered for alignment, etc.

Conventional 2-cyanoacrylate compounds or curable compositions containing a 2-cyanoacrylate compound include those described in Patent Documents 1 to 5.
Patent Document 1 describes a curable composition containing a 2-cyanoacrylate compound having an alkoxyalkyl group as an ester chain, which gives a flexible cured product.

Patent document 2 describes a conformable coating composition that includes a polymerizable cyanoacrylate monomer, an elastomer, and a volatile liquid, in which the cyanoacrylate monomer is 0.1 to 65% by weight of the nonvolatile portion, the elastomer in the elastomer phase is at least 35% by weight of the nonvolatile portion, and the volatile liquid is at least 40% by weight of the total composition.

Patent Document 3 describes a novel 2-cyanoacrylate compound having a halogenated alkoxyalkyloxycarbonyl group as the ester group.

Patent document 4 describes a flexible cyanoacrylate composition consisting of 2-cyanoacrylate and dibutyl phthalate.

Patent document 5 describes (a) at least one cyanoacrylate monomer selected from compounds of formula (I)

wherein ^R1 is a divalent linking group containing 1 to 10 carbon atoms and A represents a _C5 - _C50 aryl group or a C2- _C50 heteroaryl group; and (b) at least one (co)polymer.

Special Publication No. 61-13702 Special Publication No. 2014-528280 JP 8-283225 A JP 8-48945 A Special table 2015-523426 publication

However, although the invention described in Patent Document 1 describes flexibility, no peel strength test or evaluation of adhesive performance was carried out.
Furthermore, although Patent Document 2 describes the absence of an irritating odor or whitening phenomenon and the flexibility of the cured product, it makes no mention of peel strength tests or adhesion.
Patent Document 3 describes the elongation and durability of the cured product, but makes no mention of peel strength.
Patent Document 4 only describes flexibility and brittleness, but makes no mention of adhesiveness.
In the technique described in Patent Document 5, the composition after curing does not exhibit tackiness, and there is no description regarding peel strength and re-adhesion.

The problem that the present invention aims to solve is to provide a curable composition for temporary fixation that provides excellent adhesion to the resulting cured product and that can be easily peeled off or removed after curing.

Means for solving the above problems include the following aspects.
<1> A curable composition for temporary fixing, comprising a 2-cyanoacrylate compound represented by the following formula (1), wherein the storage modulus of a cured product of the curable composition at 23° C. is 1.0×10 ⁴ Pa or more and 1.0×10 ⁸ Pa or less:

In formula (1), ^L1 each independently represents a linear or branched alkylene group having 2 to 6 carbon atoms which may have a substituent, p represents an integer of 2 to 8, and ^R1 represents a linear or branched alkyl group, aryl group, alkenyl group, or alkynyl group having 1 to 8 carbon atoms which may have a substituent.

<2> The curable composition for temporary fixing according to <1>, which is an instant adhesive.
<3> The curable composition for temporary fixing according to <1> or <2>, wherein a glass transition temperature of a cured product of the curable composition for temporary fixing is 60° C. or lower.
<4> The curable composition for temporary fixing according to any one of <1> to <3>, wherein a tack value of the cured product of the curable composition for temporary fixing in a probe tack test is 0.1 N/ ^cm2 or more and 100 N/ ^cm2 or less.
<5> The curable composition for temporary fixing according to any one of <1> to <4>, wherein an elongation percentage in a stress-strain curve of a cured product of the curable composition for temporary fixing is 350% or more.
<6> The curable composition for temporary fixing according to any one of <1> to <5>, wherein a 180° peel adhesion strength of an adhesion product obtained by curing the curable composition for temporary fixing to adhere glass to an easily adhesive polyethylene terephthalate base material, measured in accordance with JIS Z 0237 (2009), is 5 N/25 mm or more and 100 N/25 mm or less.
<7> The curable composition for temporary fixing according to any one of <1> to <6>, wherein a 180° peel adhesion strength of an adhesion product obtained by curing the curable composition for temporary fixing to bond aluminum base materials together, measured in accordance with JIS Z 0237 (2009), is 5 N/25 mm or more and 50 N/25 mm or less.
<8> The curable composition for temporary fixing according to any one of <1> to <7>, wherein each L ¹ is independently -CH ₂ CH ₂ -, -CH(R ² )CH ₂ - or -CH ₂ CH(R ² )-, and R ² is an alkyl group having 1 to 6 carbon atoms.
<9> The curable composition for temporary fixing according to any one of <1> to <8>, wherein the p is an integer of 2 to 6.
<10> The curable composition for temporary fixing according to any one of <1> to <9>, wherein R ¹ is a linear or branched alkyl group having 1 to 6 carbon atoms.
<11> The curable composition for temporary fixing according to any one of <1> to <10>, wherein the initial viscosity of the curable composition for temporary fixing at 25°C is 300 Pa·s or less, and the time from when 1 μL of a 5 volume % solution of triethanolamine in acetone is added to 0.1 g of the curable composition for temporary fixing under an environment of 25°C and 60% RH until the storage modulus of a cured product of the curable composition for temporary fixing becomes substantially constant in the range of 1.0 x 10 ⁴ Pa or more and 1.0 x 10 ⁸ Pa or less is 60 minutes or less.
<12> The curable composition for temporary fixing according to any one of <1> to <11>, further comprising at least one compound selected from the group consisting of a tackifier, a plasticizer, a rubber toughening agent, an antioxidant, and a polymer.
<13> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing a semiconductor wafer.
<14> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing of building materials.
<15> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing of wood.
<16> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing an optical member.
<17> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing a quartz crystal unit.
<18> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing of leather.
<19> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing of cloth.
<20> The curable composition for temporary fixing according to any one of <1> to <12>, which is for temporary fixing of paper.
<21> A temporary fixing method comprising: a step of forming a layer made of the curable composition for temporary fixing according to any one of <1> to <20> between at least two members; a step of curing the layer formed between the at least two members to form a cured product, and temporarily fixing the at least two members to each other by the cured product; and a step of peeling off the at least two members.

The present invention provides a curable composition for temporary fixation that provides excellent adhesion to the resulting cured product and can be easily peeled off or removed after curing.

1 shows the elongation percentage in the stress-strain curve of the cured products of the curable compositions of Examples 2 to 4 and Comparative Example 1.

The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, the word "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.
In the numerical ranges described in this specification, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in another stepwise manner. In addition, in the numerical ranges described in this specification, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
In the present invention, "mass %" and "weight %" are synonymous, and "parts by mass" and "parts by weight" are synonymous.
Also, in the present invention, a combination of two or more preferred embodiments is a more preferred embodiment.
The present invention will be described in detail below.

(Temporary fixing curable composition)
The curable composition for temporary fixing of the present invention (hereinafter also simply referred to as "curable composition") contains a 2-cyanoacrylate compound represented by the following formula (1), and the storage modulus of a cured product of the curable composition at 23°C is 1.0 x 10 ⁴ Pa or more and 1.0 x 10 ⁸ Pa or less.

In formula (1), ^L1 each independently represents a linear or branched alkylene group having 2 to 6 carbon atoms which may have a substituent, p represents an integer of 2 to 8, and ^R1 represents a linear or branched alkyl group, aryl group, alkenyl group, or alkynyl group having 1 to 8 carbon atoms which may have a substituent.

As a result of intensive research, the inventors have found that by adopting the above-mentioned configuration, it is possible to provide a curable composition for temporary fixing which has excellent adhesion to the resulting cured product and which can be easily peeled off or removed after curing.
The mechanism of action behind this excellent effect is not clear, but is presumed to be as follows.
By including the 2-cyanoacrylate compound represented by formula (1) having 2 to 8 alkyleneoxy structures and by controlling the storage modulus at 23°C of the cured product of the temporary fixing curable composition to be within the above range, it is presumed that the cured product has flexibility even after curing, has an appropriate adhesive strength on the surface, has excellent adhesiveness, and can be easily peeled off or removed after curing.

Furthermore, the temporary fixing curable composition of the present invention contains a 2-cyanoacrylate compound represented by formula (1) having 2 to 8 alkyleneoxy structures, and by setting the storage modulus at 23°C of the cured product of the temporary fixing curable composition within the above range, the rate at which the adhesive strength increases (curing speed) is excellent, and the adhesiveness of the resulting cured product is excellent, so that the temporary fixing curable composition can be suitably used as an instant adhesive for temporary fixing.

In the present invention, "temporary fixation" refers to fixing at least two components with a cured product made of the temporary fixing curable composition of the present invention and then being able to peel them off, and the at least two components may or may not actually be peeled off.
The material to be fixed (bonded) by the curable composition for temporary fixing of the present invention is not particularly limited, and may be an inorganic compound, an organic compound, or an inorganic-organic composite, and may have any shape, and may be made of the same material or different materials.
The curable composition for temporary fixing of the present invention can fix (adhere) the following adherends (members) of the same kind or different kinds.
Examples of materials to be adhered include various components such as electronic materials such as semiconductor wafers and chips, optical materials such as lenses, prisms, polarizers, optical fibers, and optical waveguides, quartz crystal oscillators, piezoelectric elements, building materials, wall materials, lumber, wooden boards, plywood, woodworking products, glass windows, decorative items, sensors, jigs such as polishing plates, teaching materials, pottery, porcelain, woven fabrics, nonwoven fabrics, paper, thread, fiber, ingots, and leather products.
The material of the material to be adhered is not particularly limited, and examples thereof include metals, minerals such as quartz, glass, ceramics, resins, low molecular weight organic compounds, wood, plants, leather, concrete, and the like.

The curable composition for temporary fixing of the present invention can be easily and quickly cured and fixed by moisture in the air, and further can be easily peeled off, for example, by an external mechanical force or the like, so that contamination of the adherend due to temporary fixing and peeling can be suppressed, and among the adherends, the composition can be particularly suitably used for temporary fixing of semiconductor wafers, optical materials, or quartz crystal oscillators.
In addition, the curable composition for temporary fixing of the present invention can be easily and quickly cured and fixed by the moisture in the air, and can also be easily peeled off, making it easy to readjust the fixing position. Therefore, the composition can be particularly suitably used for temporary fixing of building materials or wood, which are mainly used at construction sites, in homes where DIY is done, and the like.

<Storage modulus of cured product at 23° C.>
In the curable composition for temporary fixing of the present invention, the storage modulus of the cured product of the curable composition for temporary fixing at 23°C is 1.0 x 10 ⁴ Pa or more and 1.0 x 10 ⁸ Pa or less, and from the viewpoint of the adhesiveness of the obtained cured product, it is preferably 1.0 x 10 ⁴ Pa or more and 5.0 x 10 ⁷ Pa or less, more preferably 1.0 x 10 ⁴ Pa or more and 1.0 x 10 ⁶ Pa or less, and particularly preferably 5.0 x 10 ⁴ Pa or more and 5.0 x 10 ⁵ Pa or less.
Incidentally, the "cured product of the temporary fixing curable composition" in the present invention does not have to be a completely cured product so long as it is a cured product having adhesiveness and flexibility as described above.
Furthermore, the "curing" of the curable composition for temporary fixing of the present invention means that the anionic polymerization of the 2-cyanoacrylate compound represented by the formula (1) at least partially proceeds, and the viscosity of the composition increases compared to that of the initial composition.

<Glass Transition Temperature of Cured Product>
In the curable composition for temporary fixing of the present invention, the glass transition temperature (Tg) of the cured product of the curable composition for temporary fixing is, from the viewpoint of adhesion of the obtained cured product, preferably 60° C. or lower, more preferably 35° C. or lower, further preferably −20° C. or higher and 35° C. or lower, and particularly preferably −10° C. or higher and 10° C. or lower.

The storage modulus and glass transition temperature (Tg) of the cured product of the temporary fixing curable composition of the present invention are measured by the following method.
The temporary fixing curable composition is injected between the jigs for a dynamic viscoelasticity measuring device described below that have been coated with triethanolamine, and then the storage modulus is measured using a dynamic viscoelasticity measuring device (manufactured by Anton Paar, product name "MCR301") under conditions of a frequency of 1 Hz, a temperature of 25°C, and a thickness of 300 μm. The product in which it has been confirmed that there is no change in the storage modulus is regarded as a cured product. Using the cured product, the storage modulus (E'), loss modulus (E"), and loss tangent (tan δ = E"/E') due to shear are measured at a frequency of 1 Hz and a heating rate of 2°C/min in the range of -50°C to 100°C.
In the present invention, "there is no change in storage modulus" means that the rate of change in storage modulus per minute is 1% or less of the final storage modulus at 25°C.
The glass transition temperature (Tg) of the cured product of the curable composition is determined using the peak temperature of the loss tangent (tan δ) as an evaluation index. The storage modulus is a value at 23°C.

<Tack value of cured product in probe tack test>
In the curable composition for temporary fixing of the present invention, the tack value in a probe tack test of the cured product of the curable composition for temporary fixing is, from the viewpoint of adhesion of the obtained cured product, preferably from 0.1 N/ ^cm2 to 100 N/ ^cm2 , more preferably from 1 N/ ^cm2 to 100 N/ ^cm2 , even more preferably from 10 N/ ^cm2 to 100 N/ ^cm2 , and particularly preferably from 50 N/ ^cm2 to 100 N/ ^cm2 .

The tack value in a probe tack test of the cured product of the temporary fixing curable composition of the present invention is measured by the following method.
A 38 μm thick spacer (release polyethylene terephthalate (PET) film (manufactured by Toyobo Film Solutions Co., Ltd., product name "Purex A31")) with a cutout frame was placed on a 125 μm thick easy-adhesion PET film (manufactured by Toray Industries, Inc., product name "Lumirror 125U34"), and the temporary fixing curable composition was dropped into the spacer frame. Another release PET film coated with triethanolamine was placed on top of it and laminated, and the mixture was left to stand at room temperature (25°C, the same below) for 24 hours to completely cure. After curing, the mixture was cut to a width of 15 mm and a length of 15 mm, and the release PET film was peeled off to obtain a test specimen. The test specimen was measured according to ASTM D2979:2016 (partially compliant), Japanese Pharmacopoeia 6.12. (3.4.): In accordance with the 17th revised edition of the "Probe Tack Test Method," measurements are taken using a probe tack tester (manufactured by Tester Sangyo Co., Ltd., product name "TE-6002"), and the tack value (unit: N/cm ² ) is calculated.

<Elongation in the stress-strain curve of the cured product>
In the curable composition for temporary fixing of the present invention, the elongation percentage in a stress-strain curve of the cured product of the curable composition for temporary fixing is preferably 350% or more, more preferably 500% or more, further preferably 750% or more, and particularly preferably 900% or more, from the viewpoint of adhesion and flexibility of the obtained cured product. The upper limit is preferably 10,000% or less.

The elongation percentage in a stress-strain curve of the cured product of the temporary fixing curable composition of the present invention is measured by the following method.
1 μL of triethanolamine was added to 1 g of the temporary fixing curable composition and stirred, and then the mixture was poured into a 1 mm thick silicone rubber mold placed on a release PET film (product name "Purex A31" manufactured by Toyobo Film Solutions Co., Ltd.). The mixture was covered with a release film, sandwiched between glass plates, and left to stand at room temperature for 24 hours to completely cure. After curing, the mold and release film were removed to produce a cured product with a width of 5 mm, length of 50 mm, and thickness of 1 mm. The stress-strain curve of this cured product was measured using a tensile tester (product name "Strograph V20-C" manufactured by Toyo Seiki Seisakusho Co., Ltd.) and the elongation was calculated.

<180° peel adhesion of adhesive material>
The 180° peel adhesion of an adhesive obtained by bonding a glass and an easily adhesive polyethylene terephthalate (PET) substrate by curing the curable composition for temporary fixing of the present invention, which is measured in accordance with JIS Z 0237 (2009), is measured by the following method.
In the curable composition for temporary fixing of the present invention, the 180° peel adhesion strength of an adhesion product obtained by curing the curable composition for temporary fixing to adhere glass to an easily adhesive PET substrate, measured in accordance with JIS Z 0237 (2009), is, from the viewpoint of adhesion and flexibility of the obtained cured product, preferably from 5 N/25 mm to 100 N/25 mm, more preferably from 10 N/25 mm to 50 N/25 mm, even more preferably from 10 N/25 mm to 35 N/25 mm, and particularly preferably from 10 N/25 mm to 25 N/25 mm.
In addition, in the curable composition for temporary fixing of the present invention, the 180° peel adhesion strength of an adhesion product obtained by curing the curable composition for temporary fixing to adhere aluminum substrates to each other, measured in accordance with JIS Z 0237 (2009), is preferably 5 N/25 mm or more and 50 N/25 mm or less, more preferably 5 N/25 mm or more and 35 N/25 mm or more, and particularly preferably 5 N/25 mm or more and 25 N/25 mm or less, from the viewpoint of adhesion and flexibility of the obtained cured product.

In the present invention, "easy adhesion" means that the material is easily adhered to the curable composition, and once adhered, is unlikely to peel off.

- Preparation of bonded material between glass and highly adhesive PET substrate -
A 38 μm thick spacer (release PET film (manufactured by Toyobo Film Solutions Co., Ltd., product name "Purex A31")) with a width of 25 mm and a length of 150 mm is placed on a 1 mm thick glass plate (manufactured by AGC Fabritech Co., Ltd., product name "FL11AK"), and the obtained curable composition is dropped onto the glass in the spacer frame. A 125 μm thick easy-adhesive PET film (manufactured by Toray Industries, Inc., product name "Lumirror 125U34") coated with triethanolamine is placed on top of it and laminated, and the mixture is left at room temperature for 24 hours to be completely cured. After curing, the spacer is removed, and a test piece having an adhesive layer of 38 μm thickness, 25 mm width, and 150 mm length, one side of which is a glass substrate and the other side of which is an easy-adhesive PET substrate is prepared.

- Preparation of adhesion between aluminum substrates -
A 38 μm thick spacer (release PET film (product name "Purex A31" manufactured by Toyobo Film Solutions Co., Ltd.)) with a cutout frame of 90 mm width and 150 mm length is placed on an aluminum plate of 0.1 mm thickness (material specified in JIS A6061P), and the adhesive composition is dropped onto the aluminum plate within the spacer frame. A 1 mm thick aluminum plate coated with triethanolamine is placed on top of the spacer frame and laminated, and the mixture is left to stand at room temperature for 24 hours to completely cure. After curing, the spacer is removed and the plate is cut to a width of 25 mm to prepare a test piece having an adhesive layer of 38 μm thickness, 25 mm width, and 150 mm length, with aluminum substrate on both sides.

- Peel strength measurement -
For the test specimen prepared under the above conditions, an edge of one of the substrates (the easily adhesive PET substrate in the case of an adherend between glass and an easily adhesive PET substrate) is peeled in a peeling direction of 180° at a speed of 50 mm/min for aluminum substrates and 100 mm/min for glass and an easily adhesive PET substrate, and the adhesive strength (resistance) (unit: N/25 mm) to the adherend at this time is measured.

<Viscosity of Curable Composition>
The viscosity of the curable composition for temporary fixing of the present invention at 25°C is preferably 300 Pa·s or less, more preferably 100 Pa·s or less, even more preferably 50 Pa·s or less, and particularly preferably 10 Pa·s or more and 50 Pa·s or less, from the viewpoints of application property and adhesion of the obtained cured product.
The viscosity of the curable composition for temporary fixing of the present invention is measured using an E-type viscometer manufactured by Tokimec Co., Ltd. under conditions of 25° C. and 100 rpm.

<Curing time>
In the curable composition for temporary fixing of the present invention, the time from when 1 μL of a 5 volume % solution of triethanolamine in acetone is added to 0.1 g of the curable composition for temporary fixing under an environment of 25° C. and 60% RH until the storage modulus of the cured product of the curable composition for temporary fixing becomes approximately constant in the range of 1.0 × 10 ⁴ Pa or more and 1.0 × 10 ⁸ Pa or less is preferably 60 minutes or less, more preferably 30 minutes or less, even more preferably 20 minutes or less, and particularly preferably 10 minutes or less, from the viewpoints of application property and adhesion of the obtained cured product.
The storage modulus of the cured product becomes substantially constant when the rate of change in storage modulus per minute becomes 1% or less of the final storage modulus at 25°C.
The storage modulus of the cured product is measured by the method described above.

<2-Cyanoacrylate Compound Represented by Formula (1)>
The curable composition for temporary fixing of the present invention contains a 2-cyanoacrylate compound represented by the formula (1).
Examples of the substituent that L ¹ in formula (1) may have include an aryl group, a halogen atom, an alkoxy group, an aryloxy group, a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group, and an acyloxy group.
In formula (1), each L ¹ is preferably independently -CH ₂ CH ₂ -, -CH(R ² )CH ₂ - or -CH ₂ CH(R ² )-, and more preferably -CH(R ² )CH ₂ - or -CH ₂ CH(R ² )-, from the viewpoint of the adhesiveness of the obtained cured product.
The ^R2 represents an alkyl group having 1 to 6 carbon atoms, and from the viewpoint of the adhesiveness of the resulting cured product, is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.
In addition, all R ^{2 s} in formula (1) are preferably the same group.
Specific examples of L ¹ in formula (1) include an ethylene group, a 1,2-propylene group, a 1,3-propylene group, a 2,3-propylene group, a 1,2-butylene group, a 1,3-butylene group, a 1,4-butylene group, a 2,3-butylene group, a 2,4-butylene group, a 3,4-butylene group, a 1,2-pentylene group, a 1,3-pentylene group, a 1,4-pentylene group, a 2,3-pentylene group, a 2,4-pentylene group, a 2,5-pentylene group, a 3,4-pentylene group, a 3,5-pentylene group, and a 4,5-pentylene group.
Among these, from the viewpoint of adhesiveness of the obtained cured product, an ethylene group, a 1,2-propylene group, a 1,3-propylene group, a 2,3-propylene group, a 1,2-butylene group, a 1,3-butylene group, a 1,4-butylene group, a 2,3-butylene group, a 2,4-butylene group, or a 3,4-butylene group is preferable, a 1,2-propylene group, a 1,3-propylene group, a 2,3-propylene group, or a 1,2-butylene group is more preferable, and a 1,2-propylene group or a 2,3-propylene group is particularly preferable.

The substituent that R ¹ in formula (1) may have is the same as the substituent that L ¹ may have.
From the viewpoint of adhesion of the obtained cured product, R ¹ in formula (1) is preferably a linear or branched alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 8 carbon atoms, or an alkynyl group having 2 to 8 carbon atoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms, more preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and particularly preferably a linear or branched alkyl group having 1 to 4 carbon atoms. In addition, the alkyl group is preferably a linear alkyl group.
Specific examples of R ¹ in formula (1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, an n-hexyl group, a 2-ethylhexyl group, a 1-octyl group, a 2-octyl group, an allyl group, a phenyl group, and a benzyl group.
Among these, from the viewpoint of adhesiveness of the obtained cured product, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, or an n-hexyl group is preferable, and a methyl group, an ethyl group, an n-propyl group, or an n-butyl group is more preferable.

In formula (1), from the viewpoint of the adhesiveness of the resulting cured product, p is preferably an integer of 2 to 6, more preferably an integer of 2 to 4, even more preferably 3 or 4, and particularly preferably 3. In addition, from the viewpoint of the adhesiveness and flexibility of the resulting cured product, p is preferably 3 or more.

Specific examples of the 2-cyanoacrylate compound represented by the formula (1) include 2-cyanoacrylic acid 2-(2-methoxyethoxy)ethyl, 2-(2-ethoxyethoxy)ethyl, 2-(2-propyloxyethoxy)ethyl, 2-(2-butoxyethoxy)ethyl, 2-(2-pentyloxyethoxy)ethyl, 2-(2-hexyloxyethoxy)ethyl, 2-[2-(2-methoxyethoxy)ethoxy]ethyl, 2-[2-(2-ethoxyethoxy)ethoxy]ethyl, 2-[2-(2-propyloxyethoxy) )ethoxy]ethyl, 2-[2-(2-butyloxyethoxy)ethoxy]ethyl, 2-[2-(2-pentyloxyethoxy)ethoxy]ethyl, 2-[2-(2-hexyloxyethoxy)ethoxy]ethyl, 1-(2-methoxy-1-methylethoxy)propyl-2-yl, 1-(2-methoxy-2-methylethoxy)propyl-2-yl, 2-(2-methoxy-2-methylethoxy)propyl-1-yl, 2-(2-methoxy-1-methylethoxy)propyl-2-yl, 1-(2-ethoxy-1-methylethoxy)propy pyl-2-yl, 1-(2-ethoxy-2-methylethoxy)propyl-2-yl, 2-(2-ethoxy-2-methylethoxy)propyl-1-yl, 2-(2-ethoxy-1-methylethoxy)propyl-2-yl, 1-(2-propoxy-1-methylethoxy)propyl-2-yl, 1-(2-propoxy-2-methylethoxy)propyl-2-yl, 2-(2-propoxy-2-methylethoxy)propyl-1-yl, 2-(2-propoxy-1-methylethoxy)propyl-2-yl, 1-(2-butoxy-1-methyl ethoxy)propyl-2-yl, 1-(2-butoxy-2-methylethoxy)propyl-2-yl, 2-(2-butoxy-2-methylethoxy)propyl-1-yl, 2-(2-butoxy-1-methylethoxy)propyl-2-yl, 1-(2-hexyloxy-1-methylethoxy)propyl-2-yl, 1-(2-hexyloxy-2-methylethoxy)propyl-2-yl, 2-(2-hexyloxy-2-methylethoxy)propyl-1-yl, 2-(2-hexyloxy-1-methylethoxy)propyl-2-yl,

1-[2-(2-methoxy-1-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-methoxy-2-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-methoxy-1-methylethoxy)-2-methylethoxy]propyl-2-yl, 1-[2-(2-methoxy-2-methylethoxy)-2-methylethoxy]propyl-2-yl, 2-[2-(2-methoxy-1-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-methoxy-2-methylethoxy)-1-methylethoxy]propyl-1-yl, 2- [2-(2-methoxy-1-methylethoxy)-2-methylethoxy]propyl-1-yl, 2-[2-(2-methoxy-2-methylethoxy)-2-methylethoxy]propyl-1-yl, 1-[2-(2-ethoxy-1-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-ethoxy-2-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-ethoxy-1-methylethoxy)-2-methylethoxy]propyl-2-yl, 1-[2-(2-ethoxy-2-methylethoxy)-2-methylethoxy]propyl-2-yl, 2-[2 -(2-ethoxy-1-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-ethoxy-2-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-ethoxy-1-methylethoxy)-2-methylethoxy]propyl-1-yl, 2-[2-(2-ethoxy-2-methylethoxy)-2-methylethoxy]propyl-1-yl, 1-[2-(2-propoxy-1-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-propoxy-2-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2 -(2-propoxy-1-methylethoxy)-2-methylethoxy]propyl-2-yl, 1-[2-(2-propoxy-2-methylethoxy)-2-methylethoxy]propyl-2-yl, 2-[2-(2-propoxy-1-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-propoxy-2-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-propoxy-1-methylethoxy)-2-methylethoxy]propyl-1-yl, 2-[2-(2-propoxy-2-methylethoxy)-2-methylethoxy]propyl-1-yl,

1-[2-(2-butoxy-1-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-butoxy-2-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-butoxy-1-methylethoxy)-2-methylethoxy]propyl-2-yl, 1-[2-(2-butoxy-2-methylethoxy)-2-methylethoxy]propyl-2-yl, 2-[2-(2-butoxy-1-methylethoxy)-1-methylethoxy]propyl-1-yl, 2 -[2-(2-butoxy-2-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-butoxy-1-methylethoxy)-2-methylethoxy]propyl-1-yl, 2-[2-(2-butoxy-2-methylethoxy)-2-methylethoxy]propyl-1-yl, 1-[2-(2-hexyloxy-1-methylethoxy)-1-methylethoxy]propyl-2-yl, 1-[2-(2-hexyloxy-2-methylethoxy)-1-methylethoxy]propyl-2 -yl, 1-[2-(2-hexyloxy-1-methylethoxy)-2-methylethoxy]propyl-2-yl, 1-[2-(2-hexyloxy-2-methylethoxy)-2-methylethoxy]propyl-2-yl, 2-[2-(2-hexyloxy-1-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-hexyloxy-2-methylethoxy)-1-methylethoxy]propyl-1-yl, 2-[2-(2-hexyloxy-1-methylethoxy)-2-methylethoxy]propyl-2-yl, Preferred examples of such esters include 2-[2-(2-hexyloxy-2-methylethoxy)-2-methylethoxy]propyl-1-yl, 2-[2-(2-hexyloxy-2-methylethoxy)-2-methylethoxy]propyl-1-yl, tetrapropylene glycol monomethyl ether, tetrapropylene glycol monoethyl ether, tetrapropylene glycol monopropyl ether, tetrapropylene glycol monobutyl ether, tetrapropylene glycol monopentyl ether, and tetrapropylene glycol monohexyl ether.

The 2-cyanoacrylate compound represented by the formula (1) used in the curable composition of the present invention may be used alone or in combination of two or more kinds.
The content of the 2-cyanoacrylate compound represented by the formula (1) in the curable composition of the present invention is, from the viewpoints of ease of dismantling with water, adhesion, and curability, preferably from 40 mass% to 100 mass%, more preferably from 50 mass% to 99.5 mass%, even more preferably from 60 mass% to 90 mass%, and particularly preferably from 70 mass% to 85 mass%, relative to the total mass of the curable composition.

<Other ingredients>
The curable composition of the present invention may contain other components in addition to the 2-cyanoacrylate compound represented by the formula (1).
As other components, stabilizers, curing accelerators, photopolymerization initiators, plasticizers, thickeners, particles, colorants, fragrances, solvents, strength improvers, rubber reinforcements, antioxidants, polymers, and the like that have conventionally been blended into curable compositions containing a 2-cyanoacrylate compound can be blended in appropriate amounts depending on the purpose within a range that does not impair the curability of the curable composition and the adhesion of the obtained cured product, etc.
The content of the other components is preferably less than the content of the 2-cyanoacrylate compound, and is preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total mass of the curable composition.
In particular, it is preferred that the curable composition of the present invention further contains, as other components, at least one compound selected from the group consisting of a tackifier, a plasticizer, a rubber toughening agent, an antioxidant, and a polymer.

Examples of tackifiers include rosin derivatives such as rosin ester, gum rosin, tall oil rosin, hydrogenated rosin ester, maleated rosin, and disproportionated rosin ester; terpene-based resins mainly composed of terpene phenol resins, α-pinene, β-pinene, and limonene; (hydrogenated) petroleum resins; coumarone-indene resins; hydrogenated aromatic copolymers; styrene resins; xylene resins; and (meth)acrylic polymers.

Examples of plasticizers include triethyl acetyl citrate, tributyl acetyl citrate, dimethyl adipate, diethyl adipate, dimethyl sebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisodecyl phthalate, dihexyl phthalate, diheptyl phthalate, dioctyl phthalate, bis(2-ethylhexyl) phthalate, diisononyl phthalate, diisotridecyl phthalate, dipentadecyl phthalate, dioctyl terephthalate, diisononyl isophthalate, decyl toluate, bis(2-ethylhexyl) camphorate, 2-ethylhexyl cyclohexyl carboxylate, diisobutyl fumarate, diisobutyl maleate, triglyceride caproate, 2-ethylhexyl benzoate, and dipropylene glycol dibenzoate. Among these, acetyl tributyl citrate, dimethyl adipate, dimethyl phthalate, 2-ethylhexyl benzoate, and dipropylene glycol dibenzoate are preferred because they have good compatibility with 2-cyanoacrylate compounds and high plasticizing efficiency. These plasticizers may be used alone or in combination of two or more.

As the rubber toughening agent, a known rubber toughening agent can be used, among which an ethylene acrylic acid elastomer is preferred, for example, VAMAC elastomer manufactured by DuPont.
The amount of the rubber toughening agent is preferably from 1.5 to 20 mass %, more preferably from 5 to 15 mass %, and particularly preferably from 8 to 10 mass %, based on the total mass of the curable composition.

As the antioxidant, known antioxidants can be used, and among them, hindered phenol compounds are preferred.

The polymer may be a homopolymer or a copolymer, with the copolymer being preferred.
Specific examples of the polymer include poly(meth)acrylate, polyvinyl ether, natural rubber, polyisoprene, polybutadiene, polyisobutylene, polychloroprene, butadiene acrylonitrile polymer, thermoplastic elastomer, styrene-isoprene, styrene-isoprene-styrene block copolymer, ethylene-propylene-diene polymer, styrene-butadiene polymer, poly-α-olefin, silicone, ethylene-containing copolymer, ethylene vinyl acetate, and a polymer selected from the group consisting of combinations thereof. Among these, poly(meth)acrylate or ethylene vinyl acetate copolymer is preferable.

Examples of the stabilizer include (1) aliphatic sulfonic acids such as sulfur dioxide and methanesulfonic acid, aromatic sulfonic acids such as p-toluenesulfonic acid, boron trifluoride complexes such as boron trifluoride methanol and boron trifluoride diethyl ether, HBF ₄ , trialkyl borates, and other anionic polymerization inhibitors, and (2) radical polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, catechol, pyrogallol, and other. These stabilizers may be used alone or in combination of two or more.

Any curing accelerator can be used as long as it accelerates the anionic polymerization of the 2-cyanoacrylate-based curable composition. Examples of the curing accelerator include polyether compounds, calixarenes, thiacalixarenes, pyrogallolarenes, and onium salts. These curing accelerators may be used alone or in combination of two or more.

Examples of thickeners include polymethyl methacrylate, copolymers of methyl methacrylate and acrylic esters, copolymers of methyl methacrylate and other methacrylic esters, acrylic rubber, polyvinyl acetate, polyvinyl chloride, polyurethane resins, polyamide resins, polystyrene, cellulose esters, polyalkyl-2-cyanoacrylates, and ethylene-vinyl acetate copolymers. These thickeners may be used alone or in combination of two or more.

The particles that may be incorporated in the curable composition are intended to adjust the thickness of the adhesive layer when the curable composition is used.
The average particle size of the particles is preferably from 10 μm to 200 μm, more preferably from 15 μm to 200 μm, and even more preferably from 15 μm to 150 μm.
The material of the particles is not particularly limited as long as it is insoluble in the 2-cyanoacrylate compound used and does not cause deterioration such as polymerization. Examples of the material include thermoplastic resins such as polyethylene, polypropylene, polymethylpentene, acrylic resin, polyvinyl chloride, polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polysulfone, and polyphenylene oxide; crosslinked resins such as unsaturated polyester, divinylbenzene polymer, divinylbenzene-styrene copolymer, divinylbenzene-(meth)acrylic acid ester copolymer, and diallyl phthalate polymer; inorganic compounds such as spherical silica, glass beads, and glass fibers; silicone compounds; and organic-inorganic composite particles containing an organic polymer skeleton and a polysiloxane skeleton.
The content of the particles is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, and even more preferably 1 to 3 parts by mass, relative to 100 parts by mass of the 2-cyanoacrylate compound content. When the content is in the range of 0.1 to 10 parts by mass, the effect on the curing speed and adhesive strength can be reduced.
The average particle size of the particles in the present invention is a volume-based average value measured by a laser diffraction particle size distribution measuring device.

The curable composition for temporary fixing of the present invention can be used for various applications without any particular limitation.
Among them, the curable composition for temporary fixation of the present invention can be easily peeled or removed by mechanical external force or water from the curable composition for temporary fixation at the bonded portion or the curable composition attached and cured at the unnecessary portion. For example, it can be suitably used as a curable composition for teaching materials. The cured product of the curable composition for temporary fixation of the present invention can be peeled or removed by, for example, immersing it in water at a temperature range from room temperature (15°C to 25°C) to lukewarm water (30°C to 45°C). Therefore, even if the curable composition for temporary fixation of the present invention adheres to an unnecessary portion such as a finger and hardens, it can be easily peeled or removed by water. In addition, since it can be peeled or removed by water at a temperature range from room temperature to lukewarm water, when it is used for temporary fixation in industrial applications, the amount of heat required for peeling can be reduced, and costs can be reduced.
Here, examples of temporary fixation for industrial purposes include temporary fixation of various electronic materials such as semiconductor wafers, optical materials, etc., to various jigs such as polishing plates, etc.
The adherend to be bonded by the curable composition for temporary fixing of the present invention is not particularly limited, and may be an inorganic compound, an organic compound, or an inorganic-organic composite, and may be made of the same material or different materials. The curable composition of the present invention can bond solid objects of any shape.

<Method of curing the temporary fixing curable composition>
The curing method of the curable composition for temporary fixing of the present invention is not particularly limited as long as it is capable of polymerization curing by the 2-cyanoacrylate compound, and may be cured by moisture such as humidity or by light, but curing by moisture such as humidity is preferred. Also, from the viewpoint of curing speed, curing by light is preferred.
When the curable composition for temporary fixing of the present invention is cured by light, a photopolymerization initiator is blended, and the composition can be cured by irradiating ultraviolet light or visible light using a high-pressure mercury lamp, a halogen lamp, a xenon lamp, an LED (light-emitting diode) lamp, sunlight, or the like.

(Temporary fixing method)
The curable composition for temporary fixing of the present invention can also be suitably used in a temporary fixing method.
That is, the temporary fixing method of the present invention includes:
A step of forming a layer made of the curable composition for temporary fixing of the present invention between at least two members (hereinafter also referred to as a "layer forming step"); and
It is preferable that the method includes a step of curing the layer formed between the at least two members to form a cured product, and temporarily fixing the at least two members to each other by the cured product (hereinafter, also referred to as a "temporary fixing step");
It is more preferable that the method further includes a step of peeling off the at least two members (hereinafter, also referred to as a "peeling step").
The temporary fixing method of the present invention may further include a step of processing the temporarily bonded members into a desired shape (hereinafter, referred to as a "processing step") between the temporary bonding and fixing step and the separating step.
The temporary fixing method of the present invention may include a step of preparing the curable composition for temporary fixing of the present invention (hereinafter, also referred to as a "curable composition preparation step").
Each step of the temporary fixing method of the present invention will be described below.

The curable composition preparation step is preferably a step of mixing a 2-cyanoacrylate compound and a water-soluble compound to prepare the temporary fixing curable composition according to the present invention.
The 2-cyanoacrylate compound and the water-soluble compound that can be used in this step are as described above.
In this step, the 2-cyanoacrylate and the water-soluble compound are mixed and stirred to obtain a homogeneous liquid, thereby producing a curable composition for temporary fixing. The method for mixing the 2-cyanoacrylate and the water-soluble compound is not particularly limited, but the mixture can be left standing or mixed using a stirrer or the like at a temperature between room temperature and 60° C.

The layer forming step is a step of forming a layer made of the curable composition for temporary fixing of the present invention between at least two members.
The layer forming step can be, for example, a step of applying the curable composition for temporary fixing to the adherend surface of one or more members to be temporarily fixed, and then overlapping the other member on the applied portion. In this embodiment, in order to apply the composition, a dispenser, a coater, a roll, a brush, a spatula, a spray, a coating tool, or the like may be used according to the shape of the member to be used. Alternatively, a method of immersing a pre-laminated adherend material in the curable composition for temporary fixing and allowing the curable composition to permeate the gaps in the adherend can also be mentioned. The member to be used is preferably one that is not altered by the curable composition for temporary fixing and water at a temperature of from room temperature to about 60 ° C., and the above-mentioned adherend material can be suitably used.

The temporary fixing step is a step of curing the layer formed between the at least two members to form a cured product, and temporarily fixing the at least two members together by the cured product.
Since the curable composition for temporary fixing can be cured instantly with a small amount of moisture, a cured product can be obtained without the need for special equipment or special conditions. In order to promote the curing reaction, the composition may be cured by heating to a temperature within a range that does not affect the members to be temporarily fixed, for example, from about 40° C. to 60° C.

The peeling step is a step of peeling the at least two members.
The cured product of the curable composition for temporary fixing has appropriate adhesion, and therefore can not only sufficiently fix the components to each other, but also can be easily separated by, for example, applying a mechanical external force to at least one of the components, irradiating with ultrasonic waves, or contacting the cured product with a composition containing water.
Examples of the peeling step include a method of applying a mechanical external force to the temporarily fixed member, a method of irradiating ultrasonic waves, a method of contacting the cured product with a composition containing water, and a combination of these methods.
Examples of the method for contacting the cured product with the water-containing composition include immersing the cured product in the water-containing composition, exposing it to running water, and spraying the water-containing composition onto the temporarily fixed member. The treatment time depends on the contact method of the water-containing composition and the heating temperature, but is preferably in the range of 10 seconds to 12 hours, and more preferably in the range of 10 seconds to 30 minutes. In addition, when the temporarily fixed member comes into contact with water at a temperature of from room temperature to about 60° C., it is also preferable to apply a mechanical external force to the temporarily fixed member or irradiate it with ultrasonic waves to promote separation.

The processing step is a step of processing the at least two temporarily fixed members into a desired shape between the temporary fixing step and the peeling step. In the processing step, the members may be cut, ground, polished, etched, or otherwise processed into the desired shape.

The present invention will be specifically described below based on examples. Note that the present invention is not limited to these examples. In addition, in the following, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

(Examples 1 to 4 and Comparative Example 1)
The 2-cyanoacrylate compounds shown in Table 1 or Table 2 were used as curable compositions.
The following physical property measurements and evaluations were carried out using the obtained curable composition. The evaluation results are shown in Table 1 or Table 2.

<Measurement of glass transition temperature and storage modulus of cured product>
The glass transition temperature (Tg) and storage modulus of the cured product of the curable composition were measured by the following methods.
The curable composition was injected between the jigs for a dynamic viscoelasticity measuring device described below coated with triethanolamine, and then the storage modulus was measured using a dynamic viscoelasticity measuring device (manufactured by Anton Paar, product name "MCR301") under the conditions of a frequency of 1 Hz, a temperature of 25°C, and a thickness of 300 μm. The product in which it was confirmed that there was no change in the storage modulus was defined as a cured product. The cured product was used to measure the storage modulus (E'), loss modulus (E"), and loss tangent (tan δ = E"/E') due to shear at a frequency of 1 Hz and a heating rate of 2°C/min in the range of -50°C to 100°C. The glass transition temperature (Tg) was determined using the peak temperature of the loss tangent (tan δ) as an evaluation index. The value at 23°C was used as the storage modulus.

<Measurement of tack value in probe tack test of cured product>
A 38 μm thick spacer (release polyethylene terephthalate (PET) film (manufactured by Toyobo Film Solutions Co., Ltd., product name "Purex A31")) with a cutout frame was placed on a 125 μm thick easy-adhesion PET film (manufactured by Toray Industries, Inc., product name "Lumirror 125U34"), and the adhesive composition was dropped into the spacer frame. Another release PET film coated with triethanolamine was placed on top of it and laminated, and the mixture was left to stand at room temperature (25°C, the same below) for 24 hours to completely cure. After curing, the mixture was cut to a width of 15 mm and a length of 15 mm, and the release PET film was peeled off to prepare a test specimen. The test specimen was measured according to ASTM D2979:2016 (partially compliant), Japanese Pharmacopoeia 6.12. (3.4.): In accordance with the 17th revised edition "Probe Tack Test Method", measurements were made using a probe tack tester (manufactured by Tester Sangyo Co., Ltd., product name "TE-6002"), and the tack value (unit: N/cm ² ) was calculated.

<Measurement of elongation in the stress-strain curve of the cured product>
1 μL of triethanolamine was added to 1 g of the curable composition and stirred, and then the mixture was poured into a 1 mm thick silicone rubber mold placed on a release PET film (product name "Purex A31" manufactured by Toyobo Film Solutions Co., Ltd.). The mixture was covered with a release film, sandwiched between glass plates, and left to stand at room temperature for 24 hours to completely cure. After curing, the mold and release film were removed to produce a cured product with a width of 5 mm, length of 50 mm, and thickness of 1 mm. The stress-strain curve of this cured product was measured using a tensile tester (product name "Strograph V20-C" manufactured by Toyo Seiki Seisakusho Co., Ltd.) and the elongation was calculated.

<Viscosity of Curable Composition>
The measurement was carried out using an E-type viscometer manufactured by Tokimec Co., Ltd. under conditions of 25° C. and 100 rpm.

<180° Peel Strength Test of Adhesive>
- Preparation of bonded material between glass and easily adhesive PET substrate -
A 38 μm thick spacer (release PET film (manufactured by Toyobo Film Solutions Co., Ltd., product name "Purex A31")) with a width of 25 mm and a length of 150 mm was placed on a 1 mm thick glass plate (manufactured by AGC Fabritech Co., Ltd., product name "FL11AK"), and the obtained curable composition was dropped onto the glass in the spacer frame. A 125 μm thick easy-adhesion PET film (manufactured by Toray Industries, Inc., product name "Lumirror 125U34") coated with triethanolamine was placed on top of it, and the film was left at room temperature for 24 hours to completely cure. After curing, the spacer was removed, and a test piece having an adhesive layer of 38 μm thick, 25 mm wide, and 150 mm long, one side of which was a glass substrate and the other side of which was an easy-adhesion PET substrate, was prepared.

- Preparation of adhesion between aluminum substrates -
A 38 μm thick spacer (release PET film (manufactured by Toyo Cross Co., Ltd., product name "SP3091")) with a cutout frame of 90 mm width and 150 mm length was placed on an aluminum plate of 0.1 mm thickness (material specified in JIS A6061P), and the adhesive composition was dropped onto the aluminum plate within the spacer frame. A 1 mm thick aluminum plate coated with triethanolamine was placed on top of the spacer frame and laminated, and the resulting mixture was left to stand at room temperature for 24 hours to be completely cured. After curing, the spacer was removed and the plate was cut to a width of 25 mm to prepare a test piece having an adhesive layer of 38 μm thickness, 25 mm width and 150 mm length, with aluminum substrate on both sides.

- Peel strength measurement -
For the test pieces prepared under the above conditions, an edge of one of the substrates (the easily adhesive PET substrate in the case of an adherend between glass and an easily adhesive PET substrate) was peeled in a peeling direction of 180° at a speed of 50 mm/min for aluminum substrates and 100 mm/min for glass and an easily adhesive PET substrate, and the adhesive strength (resistance) (unit: N/25 mm) to the adherend at that time was measured.

In the chemical structural formulae in Tables 1 and 2, Me represents a methyl group, Bu represents an n-butyl group, and C ₃ H ₆ O represents a mixed group of -CH(CH ₃ )CH ₂ O- and -CH ₂ CH(CH ₃ )O-. The 2-cyanoacrylate compound used in Example 1 is a mixture of positional and optical isomers.
FIG. 1 also shows the elongation percentage in the stress-strain curves of the cured products of the curable compositions of Examples 2 to 4 and Comparative Example 1.
The vertical axis in FIG. 1 represents stress (unit: N/mm ² ), and the horizontal axis represents strain (unit: %).
The details of the abbreviations in FIG. 1 are as follows: ME3CA: methoxyethoxyethoxyethyl cyanoacrylate (Example 2)
MEECA: Methoxyethoxyethyl cyanoacrylate (Example 3)
BEECA: Butoxyethoxyethyl cyanoacrylate (Example 4)
EECA: Ethoxyethyl cyanoacrylate (Comparative Example 1)

As shown in Table 1, the curable compositions for temporary fixing of Examples 1 to 4 were superior in adhesion to the cured products obtained in comparison with the curable composition for temporary fixing of Comparative Example 1.
Furthermore, as shown in Tables 1 and 2, the temporary fixing curable compositions of Examples 1 to 4 were excellent in curing speed and the obtained cured products were also excellent in flexibility.

<Temporary Fixation and Peel Test of Semiconductor Wafer>
A drop of the obtained temporary fixing curable composition was dropped onto the center of a ground glass (limestone glass, 125 mm x 400 mm x 20 mmt, Ra: 5 μm), and immediately after that, a 125 mm x 125 mm x 400 mm Si (silicon) ingot (polycrystalline silicon ingot) was placed on top and cured. In this state, the glass was left to stand at 23°C and 60% RH for 24 hours. In all of the examples 1 to 4, temporary fixing was achieved without any problems.
Thereafter, the frosted glass was fixed and the Si ingot was moved by hand, and if the Si ingot and the frosted glass peeled off, it was rated as "A." Further, the temporarily fixed assembly of the Si ingot and the frosted glass was immersed in water at 40°C for 6 hours, and the frosted glass was fixed and the Si ingot was moved by hand, and if the Si ingot and the frosted glass peeled off, it was rated as "B." If the Si ingot and the frosted glass were not peeled off, it was rated as "C."
The evaluation results are shown in Table 3.

<Temporary Fixation and Peel Test of Optical Members>
A drop of the obtained curable composition for temporary fixing was dropped onto an aluminum plate, and immediately after that, a 1 cm square glass was placed on top of it and cured. In this state, it was left to stand at 23°C and 60% RH for 24 hours. In all of the examples described below, temporary fixing was achieved without any problems.
Thereafter, the aluminum plate was fixed and the glass was moved by hand, and if the aluminum plate and the glass peeled off, it was marked "A." Further, the temporarily fixed product of the aluminum plate and the glass was immersed in water at 23°C for 6 hours, and the aluminum plate was fixed and the glass was moved by hand, and if the aluminum plate and the glass peeled off, it was marked "B." If the aluminum plate and the glass did not peel off, it was marked "C."
The evaluation results are shown in Table 3.

<Quartz Oscillator Temporary Fixation and Peel Test>
A drop of the obtained curable composition for temporary fixing was dropped onto a quartz plate measuring 5 mm in length, 40 mm in width, and 0.4 mm in thickness, and immediately after that, another quartz plate measuring 5 mm in length, 40 mm in width, and 0.4 mm in thickness was placed on top of the plate and cured. In this state, the plate was left to stand at 23°C and 60% RH for 24 hours. In all of the examples described below, temporary fixing was achieved without any problems.
After that, one of the quartz plates was fixed and the other quartz plate was moved by hand, and if the quartz plates peeled off from each other, it was marked "A". Further, the temporarily fixed product of the quartz plates was immersed in water at 23°C for 6 hours, and one of the quartz plates was fixed and the other quartz plate was moved by hand, and if the quartz plates peeled off from each other, it was marked "B". If the quartz plates did not peel off from each other, it was marked "C".
The evaluation results are shown in Table 3.

The curable composition for temporary fixing of the present invention contains a 2-cyanoacrylate compound and can be used as an instant adhesive for temporary fixing in a wide range of products and technical fields in various industrial sectors, including general household use, educational materials, building materials, the medical field, etc. It is particularly useful for temporary fixing of semiconductor wafers, optical materials, quartz crystal oscillators, building materials, or wood.
Furthermore, the curable composition for temporary fixing of the present invention can be suitably used not only for bonding between adherends of the same kind, but particularly for bonding between adherends of different kinds (for example, between a metal and a resin).

Claims (20)

1. A curable composition comprising:
The present invention includes a 2-cyanoacrylate compound represented by the following formula (1):
A curable composition for temporary fixing, wherein the storage modulus of a cured product of the curable composition at 23° C. is 1.0×10 ⁴ Pa or more and 1.0×10 ⁸ Pa or less.

In formula (1), ^L1 each independently represents a linear or branched alkylene group having 2 to 6 carbon atoms which may have a substituent, p represents 3 or 4 , and ^R1 represents a linear or branched alkyl group, aryl group, alkenyl group, or alkynyl group having 1 to 8 carbon atoms which may have a substituent. The curable composition for temporary fixing according to claim 1, which is an instant adhesive. The curable composition for temporary fixing according to claim 1 or 2, wherein the glass transition temperature of the cured product of the curable composition for temporary fixing is 60°C or lower. The curable composition for temporary fixing according to any one of claims 1 to 3, wherein a tack value in a probe tack test of a cured product of the curable composition for temporary fixing is 0.1 N/cm2 or ^more and 100 N/ ^cm2 or less. The curable composition for temporary fixing according to any one of claims 1 to 4, wherein the elongation percentage in the stress-strain curve of the cured product of the curable composition for temporary fixing is 350% or more. The curable composition for temporary fixation according to any one of claims 1 to 5, wherein the 180° peel adhesion strength of an adhesion product obtained by curing the curable composition for temporary fixation to adhere glass to an easily adhesive polyethylene terephthalate substrate, measured in accordance with JIS Z 0237 (2009), is 5 N/25 mm or more and 100 N/25 mm or less. The curable composition for temporary fixation according to any one of claims 1 to 6, wherein the 180° peel adhesion strength of an adhesive formed by curing the curable composition for temporary fixation to bond aluminum substrates together, measured in accordance with JIS Z 0237 (2009), is 5 N/25 mm or more and 50 N/25 mm or less. The curable composition for temporary fixing according to any one of claims 1 to 7, wherein each L ¹ is independently -CH ₂ CH ₂ -, -CH(R ² )CH ₂ - or -CH ₂ CH(R ² )-, and R ² is an alkyl group having 1 to 6 carbon atoms. The curable composition for temporary fixing according to any one of claims 1 to 8 , wherein R ¹ is a linear or branched alkyl group having 1 to 6 carbon atoms. The initial viscosity of the temporary fixing curable composition at 25° C. is 300 Pa s or less,
The curable composition for temporary fixing according to any one of claims 1 to 9, wherein the time from when 1 µL of a 5 volume % triethanolamine solution in acetone is added to 0.1 g of the curable composition for temporary fixing until the storage modulus of the cured product of the curable composition for temporary fixing becomes substantially constant in the range of 1.0 x 10 ⁴ Pa or more and 1.0 x 10 ⁸ Pa or less is 60 minutes or less under an environment of 25°C and 60% RH. The curable composition for temporary fixing according to any one of claims 1 to 10 , further comprising at least one compound selected from the group consisting of a tackifier, a plasticizer, a rubber toughening agent, an antioxidant, and a polymer. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing a semiconductor wafer. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing of building materials. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing of wood. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing an optical member. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing a quartz crystal oscillator. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing of leather. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing of cloth. The curable composition for temporary fixing according to any one of claims 1 to 11 , which is for temporary fixing of paper. A step of forming a layer made of the curable composition for temporary fixing according to any one of claims 1 to 19 between at least two members;
A step of curing the layer formed between the at least two members to form a cured product, and temporarily fixing the at least two members to each other by the cured product; and
The temporary fixing method further comprises a step of peeling off the at least two members.