Sealing method

Abstract

A sealing method using a photocurable sealant sheet is provided. The provided sealing method sequentially comprises: a step of preparing a photocurable sealant sheet; a step of subjecting the sealant sheet to light irradiation treatment; and a step of attaching the sealant sheet to a sealed object.

Description

Technical Field

[0001] The present invention relates to a sealing method, and more particularly to a sealing method using a photocurable sealant sheet.

[0002] This application claims priority based on Japanese Patent Application No. 2019-235155 filed on December 25, 2019, the entire contents of which are incorporated into this specification by reference. Background Art

[0003] Sealants (also called sealants or sealing agents) are widely used in various applications. For example, Patent Documents 1 and 2 disclose a liquid curable composition used as a sealant for aircraft and aerospace. As a raw material for the sealant for aircraft use as described above, liquid polysulfide polymers are known. Liquid polysulfide polymers contain -SS- bonds in the molecule, so by curing them, a rubber-like cured product with excellent resistance to oils such as jet fuel and working oil can be formed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Publication No. 2006-526693

[0007] Patent Document 2: Japanese Patent Publication No. 2008-530270 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] However, the liquid sealant disclosed in the above-mentioned prior art documents is in liquid form, and therefore it is difficult to apply it to a desired range of an object with a desired thickness and good accuracy. Therefore, even for skilled operators, there is a limit to shortening the time required for the application of the liquid sealant. In addition, there are concerns about the increase in manufacturing costs, the decrease in productivity, and the decrease in sealing quality caused by the difficulty in training and securing operators.

[0010] Therefore, the inventors did not research and develop the above-mentioned liquid sealant, but researched and developed a sealant sheet having a sheet shape before curing, and as a result, created a photocurable sealant sheet, further embodied its practical use, and completed the present invention. That is, the purpose of the present invention is to provide a sealing method using a photocurable sealant sheet.

[0011] Solutions for solving problems

[0012] The sealing method provided by the specification includes, in order: a step of preparing a photocurable sealant sheet; a step of subjecting the sealant sheet to light irradiation treatment; and a step of attaching the sealant sheet to a sealed object. The photocurable sealant sheet used in the sealing method is pre-formed into a sheet shape, so it is easy to handle. In addition, according to the sealing method, the sealant sheet is subjected to light irradiation treatment before being attached to the sealed object, so that the sealant sheet can be easily photocured well without unevenness.

[0013] As the photocurable sealant sheet used in the method disclosed herein, a delayed curing type photocurable sealant sheet can be preferably used. By using a delayed curing type photocurable sealant sheet, the degree of freedom in process design from the time the sealant sheet is subjected to light irradiation treatment to the time it is attached to the sealed object becomes higher. This can contribute to the efficiency and high precision of the sealing operation.

[0014] As the photocurable sealant sheet used in the method disclosed herein, a photoanion-curable sealant sheet can be preferably selected. Here, the photoanion-curable sealant sheet refers to a sealant sheet that is formed in a manner that utilizes anions generated by light irradiation to perform a curing reaction. Generally, anion reactions proceed more slowly than free radical reactions. Therefore, by using a photoanion-curable sealant sheet, the degree of freedom of process design during the period from the sealant sheet being subjected to light irradiation treatment to the attachment to the sealed object becomes higher. This can contribute to the efficiency and high precision of the sealing operation.

[0015] The step of attaching the light-irradiated sealant sheet to the object to be sealed is preferably performed before the 25°C storage modulus of the sealant sheet exceeds 0.7 MPa. By attaching the sealant sheet to the object to be sealed after the light-irradiation treatment and before the photocuring is performed to the extent that the 25°C storage modulus exceeds 0.7 MPa, the sealant sheet can be easily attached to the object to be sealed.

[0016] As the photocurable sealant sheet used in the method disclosed herein, it is preferable to select a photocurable sealant sheet in which the exposed surface of the sealant sheet is subjected to a 2000 mJ / cm 2 The storage modulus at 25°C after 1 hour of light irradiation (hereinafter, also referred to as "storage modulus 1 hour after light irradiation") is 0.7 MPa or less. As a result, it is easy to ensure the retention time of the softness suitable for the sealant sheet after light irradiation to be attached to the sealed object (hereinafter, also referred to as "usable time"), and the desired operation and manipulation can be performed using this time. This can contribute to the efficiency and high precision of the sealing operation.

[0017] The method disclosed herein can be preferably implemented using a photocurable sealant sheet that forms a sealant cured product having a tensile breaking strength of 0.7 MPa or more. By using such a sealant sheet, the reliability of sealing can be improved.

[0018] The photocurable sealant sheet used in the method disclosed herein preferably has a storage modulus of 0.005 MPa or more and 0.6 MPa or less at 25°C before the light irradiation treatment. By using such a photocurable sealant sheet, it is possible to achieve a good balance between the sheet shape maintenance and the adhesion to the sealed object when the sheet is attached to the sealed object after the light irradiation treatment.

[0019] The photocurable sealant sheet used in the method disclosed herein is preferably formed of a polysulfide-based sealant. The sealant sheet can exhibit excellent oil resistance by having a polysulfide structure.

[0020] The photocurable sealant sheet used in the method disclosed herein preferably contains a photobase generator. The sealant sheet containing the photobase generator is configured in such a way that a base is generated by the photobase generator by light irradiation, thereby promoting the curing reaction. Therefore, by storing it in an environment where the generation of a base by the above-mentioned photobase generator is suppressed, good storage properties can be exhibited. As the above-mentioned photobase generator, for example, a compound containing a biguanide-type cation (biguanide-based ionic photobase generator) can be preferably used. Using the photobase generator, a sealant sheet that has a good balance between good storage properties before use and good curability (photoanion curability) during use can be appropriately realized.

[0021] According to the specification, a photocurable sealant sheet used in any method disclosed herein is provided. The photocurable sealant sheet is preferably a delayed curing type photocurable sealant sheet (for example, a photoanion curable sealant sheet). The method disclosed herein can be preferably implemented using such a photocurable sealant sheet.

[0022] It should be noted that solutions obtained by appropriately combining the above-mentioned elements and solutions obtained by partially separating the elements may also be included in the scope of the invention for which patent protection is requested through this patent application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a cross-sectional view schematically showing a configuration example of a sealant sheet.

[0024] Figure 2 This is a cross-sectional view schematically showing another configuration example of the sealant sheet.

[0025] Figure 3 This is an explanatory diagram showing a sealing method according to one embodiment.

[0026] Figure 4This is an explanatory diagram showing a sealing method according to one embodiment.

[0027] Figure 5 It is an explanatory diagram showing a sealing structure formed by a sealing method according to an embodiment.

[0028] Figure 6 This is an explanatory diagram showing a sealing method according to another embodiment.

[0029] Figure 7 This is an explanatory diagram showing a sealing method according to another embodiment.

[0030] Figure 8 This is an explanatory diagram showing a sealing method according to another embodiment.

[0031] Fig. 9 It is an explanatory diagram showing a sealing structure formed by a sealing method according to another embodiment.

[0032] Fig.10 This is an explanatory diagram showing a sealing method according to another embodiment. DETAILED DESCRIPTION

[0033] The following describes a suitable embodiment of the present invention. It should be noted that, for matters necessary for the implementation of the present invention other than matters specifically mentioned in this specification, those skilled in the art can understand based on the teachings on the implementation of the invention recorded in this specification and the common knowledge at the time of application. The present invention can be implemented based on the contents disclosed in this specification and the common knowledge in the art. In addition, in the following drawings, the same symbols are sometimes used to mark components and parts that play the same role, and repeated descriptions are sometimes omitted or simplified. In addition, the embodiments described in the drawings are schematically illustrated in order to clearly illustrate the present invention, and do not necessarily accurately represent the size and scale of the actual product provided.

[0034] <Configuration Example of Sealant Sheet with Release Liner>

[0035] As the sealant sheet in the method disclosed herein (including a sealing method, a method for forming a sealant cured product, a method for manufacturing a sealed object sealed with a sealant cured product, etc., the same applies hereinafter), a photocurable sealant sheet is used. In some embodiments, the above-mentioned photocurable sealant sheet is used in the form of a sealant sheet with a release liner including a release liner having a release surface abutting at least one surface of the sealant sheet. Therefore, the process of preparing a photocurable sealant sheet in the sealing method disclosed herein can be a process of preparing a sealant sheet with a release liner including the photocurable sealant sheet as a constituent element. By using the sealing method using a sealant sheet with a release liner, the sealant sheet can be handled in a state stacked on the release liner, so the handleability (for example, dimensional stability, transportability, processability, etc.) of the sealant sheet is good. In addition, the surface of the sealant sheet is protected by the release liner, so that deformation caused by external force, dust adhesion and other contamination can be prevented.

[0036] The configuration of the sealant sheet with a release liner that can be used in the method disclosed herein is shown in Figure 1 , 2 .

[0037] Figure 1 The sealant sheet 100 with release liner shown in the figure comprises: a photocurable sealant sheet 21, and release liners 31, 32 arranged on both sides of the sealant sheet 21. More specifically, one surface (first surface) 21A and the other surface (second surface) 21B of the sealant sheet 21 are protected by release liners 31, 32, respectively, at least the sealant sheet 21 side being a release surface. The two release liners 31, 32 are in contact with each side of the sealant sheet 21 in a state where they can be peeled off from the sealant sheet 21, and can be peeled off with a light peeling force at an appropriate time.

[0038] Each of the release liners 31 and 32 can be light-transmissive or light-shielding. That is, the release liners 31 and 32 can be both light-transmissive, both light-shielding, or one light-transmissive and the other light-shielding. The sealant sheet 21 in which at least one of the release liners 31 and 32 is light-transmissive can be cured by irradiating light across its light-transmissive release liner. It is preferred to irradiate light across the light-transmissive release liner from the viewpoints of preventing dust adhesion and other contamination on the surface of the sealant sheet 21 and improving the handleability of the sealant sheet 21. In addition, the sealant sheet 21 can be cured by irradiating light to the surface (exposed surface) that is not protected by the release liner. It is advantageous to irradiate light to the exposed surface of the sealant sheet 21 from the viewpoints of the utilization efficiency of light energy. For example, the sealant sheet 21 in which both the release liners 31 and 32 are light-shielding can be cured by exposing the surface of the sealant sheet 21 by peeling off one or both release liners and irradiating light to the exposed surface. The sealant sheet 21 may be irradiated with light from either the first surface 21A or the second surface 21B, or from both sides.

[0039] Figure 2 The sealant sheet 200 with a release liner shown in the figure comprises: a photocurable sealant sheet 21, and a release liner 31 disposed on one surface 21A of the sealant sheet 21. More specifically, the sealant sheet 21 can be formed as follows: one surface 21A thereof is protected by a release liner 31 having two release surfaces, and when the sealant sheet 21 is rolled up, the other surface 21B of the sealant sheet 21 abuts against the back surface of the release liner 31, whereby the surface 21B is also protected by the release liner 31. The release liner 31 abuts against the surface 21A of the sealant sheet 21 in a state that it can be peeled off from the sealant sheet 21, and can be peeled off and removed with a light peeling force at an appropriate time. The release liner 31 can be light-transmissive or light-shielding.

[0040] <Sealing agent sheet>

[0041] The sealant sheet used in the method disclosed herein is preformed into a sheet shape and can be processed in the form of the sheet shape (for example, light irradiation is implemented, and it is arranged to the sealing object part, etc.). In this regard, the above-mentioned sealant sheet is clearly distinguished from the liquid sealant applied to the sealing object part in a liquid form (for example, a liquid sealant prepared by mixing A liquid containing a liquid polysulfide polymer and B liquid containing a curing agent of the polysulfide polymer just before construction). In addition, the sealant sheet used in the method disclosed herein is a light-curable sealant sheet that is cured by light irradiation. In terms of having the above-mentioned curability, the light-curable sealant sheet used in the method disclosed herein is clearly distinguished from the cured sealant (sealant cured product). Here, "light-curable" means that it can be cured by light irradiation. Therefore, the light-curable sealant sheet is a term referring to the state before complete curing. The method disclosed herein is preferably implemented in a manner that the light-curable sealant sheet is attached to the sealing object after being subjected to light irradiation treatment and before the sealant sheet is completely cured. The photocurable sealant sheet after the light irradiation treatment and before complete curing can be understood as a sealant sheet in a semi-cured state that can be further cured after being arranged at a sealing target site.

[0042] As the sealant sheet used in the method disclosed herein, a delayed curing type photocurable sealant sheet can be preferably used. Here, the delayed curing type photocurable sealant sheet refers to a sealant sheet that is subjected to a 2000 mJ / cm2 radiation on the exposed surface using a black light lamp at 25°C. 2 The time from the light irradiation to the time when the 25°C storage modulus of the sealant sheet rises to twice the 25°C storage modulus before the light irradiation (i.e., the initial storage modulus described later) (hereinafter also referred to as "curing delay time") is 1 hour or more. By using such a light-curing sealant sheet, it is easy to ensure that the usable time of the sealant sheet after the light irradiation treatment is a certain length, and using this time, it is possible to implement, for example, desired operations, operations (for example, the transportation, processing, cleaning of the attachment object, pretreatment, etc. of the sealant sheet), or adjust the operation period. The above-mentioned curing delay time can be more than 2 hours, more than 3 hours, more than 6 hours, more than 12 hours, or more than 24 hours. For the above-mentioned curing delay time, from the viewpoint of shortening the aging space occupation period until the formation of the sealed cured product, shortening the waiting time when waiting for the formation of the sealed cured product and performing the subsequent process, it is usually appropriate to be less than 14 days, preferably less than 7 days, less than 5 days, or less than 72 hours.

[0043] The sealant sheet used in the method disclosed herein (i.e., the sealant sheet before the light irradiation treatment) preferably has a shape retention to the extent that the sheet shape can be stably maintained at room temperature (e.g., around 25°C). The above-mentioned shape retention can also be understood as resistance to plastic deformation such as flow. The 25°C storage modulus of the sealant sheet used in the method disclosed herein (i.e., the storage modulus at 25°C of the sealant sheet before the light irradiation treatment. Hereinafter, also referred to as the "initial storage modulus") may, for example, exceed 0.005MPa, preferably exceed 0.01MPa. If the initial storage modulus of the sealant sheet is high, the handleability and processability (e.g., cutting property, anti-blocking property, reprocessability, etc.) of the sealant sheet tend to be improved. In some embodiments, it is appropriate for the initial storage modulus of the sealant sheet to be 0.02MPa or more, for example, it may be 0.05MPa or more, 0.1MPa or more, or 0.2MPa or more. The upper limit of the initial storage modulus is not particularly limited, and may be, for example, 1 MPa or less. From the viewpoint of widening the range of options for the time until the sealant sheet after the light irradiation treatment is attached to the sealed object, in some embodiments, the initial storage modulus of the sealant sheet is appropriately 0.8 MPa or less, preferably 0.6 MPa or less, more preferably 0.5 MPa or less, and may be 0.4 MPa or less, 0.3 MPa or less, 0.2 MPa or less, or 0.1 MPa or less.

[0044] The sealant sheet after light irradiation treatment is preferably attached to the sealed object before excessive photocuring is performed. The method disclosed herein can be implemented, for example, in a manner that the sealant sheet after light irradiation treatment is attached to the sealed object before the 25°C storage modulus of the sealant sheet exceeds 1 MPa. Hereinafter, the 25°C storage modulus of the sealant sheet when attached to the sealed object is also referred to as "storage modulus when attached". From the viewpoint of the tightness to the sealed object, the storage modulus of the sealant sheet when attached is, for example, less than 1 MPa, 0.9 MPa or less is advantageous, 0.7 MPa or less is appropriate, preferably 0.6 MPa or less, more preferably 0.5 MPa or less, 4 MPa or less, 0.3 MPa or less, or 0.2 MPa or less. In addition, from the viewpoint of the handling property and processability (for example, cutting property, anti-blocking property, reprocessability, etc.) of the sealant sheet during the period from the light irradiation treatment to the attachment to the sealed object, the storage elastic modulus of the sealant sheet during attachment is usually more than 0.01 MPa, preferably 0.02 MPa or more, and may be 0.05 MPa or more, 0.1 MPa or more, or 0.2 MPa or more.

[0045] It is appropriate that the storage modulus of the photocurable sealant sheet used in the method disclosed herein is less than 1 MPa one hour after light irradiation, preferably less than 0.7 MPa. Thus, it is easy to ensure that the usable time of the sealant sheet after light irradiation is a certain length, and with this time, it is possible to implement, for example, desired operations, operations (for example, the conveying, processing, cleaning of the attachment object part, pretreatment, etc. of the sealant sheet), or adjust the operation period. In some embodiments, from the viewpoint of improving the adhesion of the sealed object or extending the usable time, the storage modulus of the sealant sheet one hour after light irradiation can be, for example, less than 0.6 MPa, less than 0.5 MPa, less than 0.4 MPa, less than 0.3 MPa, or less than 0.2 MPa. In addition, from the viewpoint of the handling property and processability (for example, cutting property, anti-blocking property, reprocessability, etc.) of the sealant sheet from the time of light irradiation until the sealant sheet is attached to the sealed object, the storage elastic modulus 1 hour after light irradiation is usually more than 0.01 MPa, preferably 0.02 MPa or more, and may be 0.05 MPa or more, 0.1 MPa or more, or 0.2 MPa or more.

[0046] As the photocurable sealant sheet used in the method disclosed herein, it is preferred that the sealant cured product formed by the sealant sheet has a 25°C storage modulus of 0.8 MPa or more. By using such a sealant sheet, the reliability of the seal can be improved. In some embodiments, the 25°C storage modulus of the sealant cured product may be greater than 1.0 MPa, greater than 1.2 MPa, or greater than 1.5 MPa. There is no particular limit on the upper limit of the 25°C storage modulus of the sealant cured product. The 25°C storage modulus of the sealant cured product may be, for example, less than 5.0 MPa, less than 3.0 MPa, or less than 2.0 MPa.

[0047] It should be noted that in this specification, each of the above storage moduli is measured using a viscoelasticity tester in a measurement environment of 25°C, under the conditions of a frequency of 1 Hz and a strain of 0.5%. As a viscoelasticity tester, a model "ARES G2" manufactured by TA Instruments Japan Inc. or its equivalent can be used. The storage modulus is measured in more detail by the method described in the examples described later.

[0048] The sealant sheet used in the method disclosed herein was subjected to a 2000 mJ / cm2 radiation on the exposed surface of the sealant sheet using a black light lamp in an environment of 25°C. 2The time until the 25°C storage modulus of the sealant sheet reaches 0.7MPa after light irradiation (hereinafter also referred to as "delay time") is appropriately 5 minutes or more, preferably 10 minutes or more, more preferably 15 minutes or more, and further preferably 30 minutes or more. The sealant sheet with a longer delay time tends to have a longer usable time in the method disclosed herein. As a result, the range of choice of time from the step of subjecting the sealant sheet to light irradiation to the step of attaching the sealant sheet to the sealed object becomes wider, which can improve the flexibility of process design. From this point of view, in some embodiments, the delay time can be more than 1 hour, more than 3 hours, more than 6 hours, more than 12 hours, or more than 24 hours. There is no particular limit to the upper limit of the delay time, for example, it can be less than 60 days, less than 30 days, or less than 20 days. From the viewpoints of shortening the period of aging space occupation until the sealed cured product is formed, shortening the waiting time when waiting for the formation of the sealed cured product and carrying out subsequent steps, in some embodiments, it is appropriate for the above-mentioned delay time to be less than 14 days, preferably less than 7 days, less than 5 days, or less than 72 hours.

[0049] The thickness of the photocurable sealant sheet used in the method disclosed herein is not particularly limited and can be selected according to the thickness of the target sealant cured product. From the perspective of the reliability of the seal, in some methods, the thickness of the sealant sheet can be, for example, 0.01 mm or more, 0.03 mm or more, 0.05 mm or more, 0.1 mm or more, or 0.15 mm or more. The method disclosed herein can also be appropriately implemented in a manner using a sealant sheet having a thickness of, for example, more than 0.3 mm, more than 0.5 mm, more than 1 mm, or more than 1.5 mm. In addition, in some methods, the thickness of the sealant sheet can be, for example, less than 10 mm, less than 5 mm, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, or less than 0.3 mm. If the thickness of the sealant sheet becomes smaller, there is a tendency for the photocurability to be improved. For reducing the thickness of the sealant sheet, it is advantageous from the perspectives of followability to the surface shape of the sealing object part and lightweight.

[0050] <Example of Implementation of Sealing Method>

[0051] Hereinafter, some specific embodiments and modified examples of the sealing method disclosed herein are illustrated with reference to the drawings, but the sealing method disclosed herein is not intended to be limited to the contents shown in these specific examples.

[0052] (First Embodiment)

[0053] The sealing method of this embodiment is performed as follows.

[0054] First, prepare Figure 1 The sealant sheet 100 with a release liner of the structure shown (step S10, preparation process). In the sealant sheet 100 with a release liner used in the present embodiment, the release liners 31 and 32 are both light-shielding. As a result, the sealant sheet 21 is kept away from light during the storage of the sealant sheet 21 (before light irradiation treatment in the sealing method disclosed herein), and the storage stability (quality stability) of the sealant sheet 21 can be improved. As the sealant sheet 21, for example, a sealant sheet having an initial storage modulus in the range of 0.02MPa to 0.1MPa is used. It should be noted that when preparing the sealant sheet 100 with a release liner, in order to make it into an appropriate size for easy handling, or in order to conform to the shape and size of the sealed object, the sealant sheet 100 with a release liner may be cut into a desired shape (for example, punching using a Thomson knife, cutting based on a tape cutter, etc.).

[0055] Next, the release liner 31 is peeled off from the sealant sheet 21 to expose the first surface 21A. Figure 3 As shown, a light irradiation treatment is performed on the sealant sheet 21 from the exposed first surface 21A side (step S14, light irradiation process). The light irradiation treatment can be performed on a workbench of an exposure device (not shown) by placing the sealant sheet 100 with a release liner (the release liner 31 is peeled off) on the workbench. The type and irradiation amount of the light source are determined according to the composition and structure of the sealant sheet 21 so that the light curing of the sealant sheet 21 is appropriately performed.

[0056] Then, if Figure 4 As shown, the sealant sheet 21 subjected to the light irradiation treatment is attached to the sealing target portion of the sealing target 10 (step S16, attaching step). Figure 4 In the example shown, the sealing object 10 includes a member 12 and a member 14 partially arranged thereon, and the sealant sheet 21 is attached to the portion from the outer edge of the member 14 to the upper surface of the member 12 in a manner that covers the end of the member 14 and blocks the joint with the member 12. The process of attaching the sealant sheet 21 to the sealing object 10 is performed before the photocuring of the sealant sheet 21 is completed, for example, before the 25°C storage modulus of the sealant sheet 21 exceeds 0.2 MPa. In the present embodiment, the sealing sheet 21 is attached to the sealing object 10 in a state where the release liner 32 is laminated on the second surface 21B. As a result, the first surface 21A of the sealant sheet 21 can be easily and accurately pressed against the sealing object 10.

[0057] As a modified example, the sealant sheet 21 may be attached to the sealing object 10 after the release liner 32 is removed from the second surface 21B. This can improve the followability of the sealant sheet 21 to the surface shape of the sealing object 10. The operation of pressing the sealant sheet 21 to the sealing object 10 after removing the release liner 32 can be performed using a jig, a film, a glove, etc. having a releasable surface as needed.

[0058] The time until the sealant sheet 21 is attached to the sealing object 10 after the above-mentioned light irradiation treatment can be set within the range in which the attachment can be appropriately performed, for example, it can be set to within 24 hours or within 12 hours just after the irradiation. During this period, the sealant sheet 21 can be operated as required in the state where the release liner 32 is stacked on the second surface 21B: transportation from the exposure device to the place where the sealing object is attached, shape processing (for example, punching processing using a Thomson knife), etc., and can be temporarily stored in order to cope with the interruption of the operation caused by time adjustment until the preparation of the sealing object 10 is complete (for example, the implementation of the previous process of the sealing object, transportation, cleaning of the sealing object part, pretreatment, etc.), machine inspection, operator's instructions, etc. Alternatively, the method disclosed herein can also be implemented in a manner that the sealant sheet 21 after the light irradiation treatment is immediately attached to the sealing object 10.

[0059] After the sealant sheet 21 is attached to the sealed object 10, the release liner 32 is removed from the second surface 21B (see Figure 5 ), so that the curing of the sealant sheet 21 proceeds to form a sealant cured product (step S18, curing process). In this way, the sealed object 10 is sealed by the sealant cured product. The removal of the release liner 32 can be performed immediately after the sealant sheet 21 is attached to the sealed object 10, can be performed after the sealant cured product is formed, or can be performed at any time in between. Removing the release liner 32 at an early stage after the sealant sheet 21 is attached is advantageous from the perspective of the tightness of the sealant sheet 21 to the sealed object 10 and the shape accuracy. Removing the release liner 32 after the sealant sheet 21 has been cured to a considerable extent (which can be after the sealant cured product is formed) is advantageous from the perspective of preventing dust from adhering to the second surface 21B.

[0060] It should be noted that in the sealing method disclosed herein, the sealant sheet 21 treated with light irradiation can be cured by placing the sealant sheet 21 attached to the sealing object 10 at room temperature (e.g., 20°C to 30°C, typically around 25°C) to form a sealant cured product, so there is no need to perform additional curing treatment (e.g., light irradiation, heating, etc.) on the sealant sheet 21 after attaching to the sealing object 10. However, the sealant sheet 21 can be appropriately subjected to additional curing treatment on the sealing object 10 within the limit that no special inconvenience is caused, and the scheme of performing such additional curing treatment can also be included in the concept of the sealing method disclosed herein.

[0061] (Second Embodiment)

[0062] The sealing method of this embodiment is performed as follows.

[0063] As in the first embodiment, prepare Figure 1 The sealant sheet 100 with a release liner having the structure shown (step S10, preparation step). In the sealant sheet 100 with a release liner used in the present embodiment, the release liner 31 is light-transmissive. The release liner 32 may be light-transmissive or light-shielding.

[0064] Next, a light irradiation treatment is performed to irradiate the sealant sheet 21 with light over the release liner 31 (step S14, light irradiation step). The light irradiation treatment can be performed in the same manner as the light irradiation in the first embodiment, except that the sealant sheet 21 is irradiated with light from at least the first surface 21A side over the release liner 31. In addition, when the release liner 32 is light-transmissive, for example, Figure 6 As shown, the sealant sheet 21 is irradiated with light from both sides of the sealant sheet 21 over the release liners 31 and 32. Thus, the time required for the light irradiation treatment can be shortened.

[0065] The release liner 31 is peeled off from the light-irradiated sealant sheet 21 to expose the first surface 21A. Figure 4 As shown, the sealant sheet 21 is attached to the sealing target portion of the sealing target object 10 (step S16, attaching process), and the sealant sheet 21 is cured at room temperature to form a sealant cured product (step S18, curing process). The above-mentioned attaching process and curing process can be implemented in the same manner as the attaching process and curing process in the first embodiment.

[0066] (Third Embodiment)

[0067] The sealing method of this embodiment is performed as follows.

[0068] As in the second embodiment, prepare Figure 1Sealant sheet 100 with release liner having the structure shown (step S10, preparation step) In the sealant sheet 100 with release liner used in the present embodiment, both the release liners 31 and 32 are light-transmissive.

[0069] like Figure 6 As shown, the sealant sheet 21 is irradiated with light from both sides of the sealant sheet 21 via the release liners 31 and 32 (step S14 , light irradiation step).

[0070] The first surface 21A exposed by peeling off the release liner 31 from the sealant sheet 21 subjected to light irradiation treatment is as follows: Figure 7 Attached to the member 12 as shown, then, as Fig. 9 As shown, the member 16 is attached to the second surface 21B ( Figure 8 ) (Step S16, attaching process). Thus, the sealed object 10 in the present embodiment includes the component 12 and the component 16, and the sealant sheet 21 is arranged between the component 12 and the component 16. The arrangement of the sealant sheet 21 between the components 12 and 16 (i.e., the attachment of the components 12 and 16 to the sealant sheet 21) is performed before the photocuring is completed, for example, before the 25°C storage modulus of the sealant sheet 21 exceeds 0.2 MPa.

[0071] Thereafter, the sealant sheet 21 is allowed to cure by being left at room temperature, thereby forming a sealant cured product (step S18, curing step). In this way, the gaps between the members 12 and 16 constituting the sealed object 10 are sealed by the sealant cured product.

[0072] It should be noted that, as a modified example, light irradiation can be performed from one side (e.g., the first surface 21A side) of the sealant sheet 21 over the release liner. In addition, light-shielding release liners 31 and 32 can be used in the same manner as in the first embodiment, and the first surface 21A exposed by peeling off the release liner 31 can be irradiated with light.

[0073] (Fourth Embodiment)

[0074] The sealing method of this embodiment is performed as follows.

[0075] As in the first embodiment, prepare Figure 1 Sealant sheet 100 with release liner having the structure shown (step S10, preparation step) In the sealant sheet 100 with release liner used in the present embodiment, both the release liners 31 and 32 are light-shielding.

[0076] The release liner 32 is peeled off from the sealant sheet 21 to expose the second surface 21B, and the exposed second surface 21B is attached to the member 16 ( Fig.10 ).

[0077] Next, the release liner 31 is peeled off from the sealant sheet 21 to expose the first surface 21A, and the sealant sheet 21 is irradiated with light from the exposed first surface 21A side (step S14 , light irradiation step).

[0078] Afterwards, if Fig. 9 As shown, the first surface 21A side of the sealant sheet 21 treated with light irradiation is attached to the component 12 (step S16, attaching process). In this way, the sealed object 10 in this embodiment includes the component 12 and the component 16, and the sealant sheet 21 is arranged between the component 12 and the component 16, as in the third embodiment. The arrangement of the sealant sheet 21 between the components 12 and 16 (that is, the attachment of the components 12 and 16 to the sealant sheet 21) is performed before the photocuring is completed, for example, before the 25°C storage modulus of the sealant sheet 21 exceeds 0.2 MPa.

[0079] <Constitutional Materials of Sealant Sheet>

[0080] The sealant sheet that can be used in the method disclosed herein is described in more detail below. The material of the sealant sheet disclosed herein is not particularly limited, and various photocurable materials can be used. For example, silicone-based, modified silicone-based, silylated acrylate-based, acrylic acid-based, acrylic urethane-based, polyurethane-based, polysulfide-based, polyisobutylene-based, butyl rubber-based and other sealant materials can be used. Among them, polysulfide-based sealant materials with excellent oil resistance are preferred. The polysulfide-based sealant material is described below as an appropriate example, but the constituent material of the sealant sheet disclosed herein is not limited to the polysulfide-based sealant material.

[0081] <Polysulfide polymer (A)>

[0082] In some preferred embodiments, as the photocurable sealant sheet, a photocurable sealant sheet containing a polysulfide polymer (A) is used. The polysulfide polymer (A) is a polymer having a repeating unit containing a disulfide structure represented by -SS-, and contributes to improving the oil resistance of the cured product formed by the sealant sheet. In the sealant sheet of type (I) disclosed herein, as the polysulfide polymer (A), the epoxy-containing polysulfide polymer (AB) is included. In the sealant sheet of type (II) disclosed herein, as the polysulfide polymer (A), the thiol-containing polysulfide polymer (AC) is included.

[0083] The number of disulfide structures contained in one molecule of the polysulfide polymer (A) may be 1 or more than 2. From the viewpoint of oil resistance of the cured product, a polysulfide polymer (A) containing an average of 3 or more disulfide structures per molecule may be preferably used. The average value of the number of disulfide structures per molecule of the polysulfide polymer (A) (hereinafter also referred to as the average disulfide base number) may be, for example, 5 or more, 10 or more, 15 or more, or 20 or more. The upper limit of the average disulfide base number is not particularly limited, and from the viewpoint of ease of manufacture of the sealant sheet (for example, ease of forming into a sheet shape), for example, it may be 100 or less, 70 or less, or 50 or less.

[0084] The disulfide structure is preferably contained in the main chain of the polysulfide polymer (A). When the disulfide structure is contained in the main chain, a cured product having good elongation tends to be formed.

[0085] In some embodiments, the polysulfide polymer (A) preferably includes a repeating unit represented by the following general formula (1).

[0086] -R 1 -OR 2 -OR 3 -SS- (1)

[0087] Here, in the general formula (1), R 1 , R 2 , R 3 Each is independently an alkylene group having 1 to 4 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms, and more preferably an alkylene group having 1 to 2 carbon atoms. The repeating unit (1) has a structure in which an ether structure and a disulfide structure are linked. The polysulfide polymer (A) having such a repeating unit (1) tends to form a cured product having excellent oil resistance and flexibility. The average value of the number of the repeating units (1) contained in one molecule of the polysulfide polymer (A) may be, for example, 5 or more, 10 or more, 15 or more, or 20 or more. In addition, the average value may be, for example, 100 or less, 70 or less, or 50 or less. The polysulfide polymer (A) may have only one region in which the repeating unit (1) is continuous, or may have two or more regions.

[0088] In some embodiments, the polysulfide polymer (A) may include at least one of the structure represented by the following general formula (2a) and the structure represented by the following general formula (2b).

[0089] -CH 2 -S-CH 2 CHOH-R' (2a)

[0090] -CH 2 -S-CH(CH 2 OH)-R' (2b)

[0091] Here, R' in the general formula (2a) and (2b) is an organic group having at least one (e.g., about 1 to 5) epoxy group. The structures of the general formula (2a) and (2b) are, for example, 2 The number of structures represented by the general formula (2a) or (2b) (when both the structure represented by the general formula (2a) and the structure represented by the general formula (2b) are included, the total number thereof) may be, for example, 1.1 or more, 1.3 or more, 1.5 or more, 1.8 or more, 2.0 or more, or more than 2.0, based on the average value per molecule of the polysulfide polymer (A). In addition, the above average value may be, for example, 15 or less, 10 or less, 7.0 or less, or 5.0 or less.

[0092] The structures represented by the general formulae (2a) and (2b) can be formed by an addition reaction between a thiol group and an epoxy group. The polysulfide polymer (A) comprising the structures represented by the general formulae (2a) and (2b) can be, for example, a reaction product of a thiol-containing polysulfide having a disulfide structure and a thiol group in one molecule and an epoxy compound having two or more epoxy groups in one molecule, or a modified product thereof.

[0093] The weight average molecular weight (Mw) of the thiol group-containing polysulfide as a precursor of the polysulfide polymer (A) is not particularly limited, and may be, for example, 500 or more, 800 or more, 1000 or more, more than 1000, or more than 2000. If a thiol group-containing polysulfide having a higher Mw is used, there is a tendency to form a sealant sheet that provides a cured product with better elongation. In some embodiments, the Mw of the thiol group-containing polysulfide may be, for example, more than 2500, more than 3000, or more than 3500. In addition, the Mw of the thiol group-containing polysulfide may be, for example, less than 30000, or less than 10000. From the viewpoint of handling properties and reactivity with the epoxy compound, in some embodiments, the Mw of the thiol group-containing polysulfide may be, for example, less than 9000, less than 8000, less than 7500, less than 7000, or less than 6500.

[0094] It should be noted that in this specification, the Mw of polymers such as thiol group-containing polysulfide, epoxy group-containing polysulfide described later, and polysulfide polymer (A) can be obtained by polyethylene glycol conversion by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a mobile phase. Alternatively, the nominal value described in catalogs, documents, etc. can be used.

[0095] The above-mentioned thiol group-containing polysulfide preferably contains the above-mentioned disulfide structure in the main chain. If a sealant sheet containing a polysulfide polymer (A) which is a reaction product of a thiol group-containing polysulfide containing a disulfide structure in the main chain and an epoxy compound having two or more epoxy groups in one molecule or a modified product thereof is used, there is a tendency to form a cured product with good elongation. The number of disulfide structures contained in one molecule of the thiol group-containing polysulfide can be, for example, 3 or more, 5 or more, 10 or more, 15 or more, or 20 or more, based on the average value (average number of disulfide groups) of the entire thiol group-containing polysulfide used. The upper limit of the average number of disulfide groups is not particularly limited, and from the viewpoint of the ease of manufacturing the sealant sheet (for example, the ease of forming into a sheet shape), for example, it can be 100 or less, 70 or less, or 50 or less.

[0096] The number of thiol groups contained in the thiol group-containing polysulfide as a precursor of the polysulfide polymer (A) may be 1 or 2 or more per molecule of the thiol group-containing polysulfide. From the viewpoint of easily realizing a sealant sheet suitable for improving the strength of a cured product and shortening the curing time, a thiol group-containing polysulfide having an average number of thiol groups contained in one molecule of greater than 1 is preferred. The average number of thiol groups per molecule of the thiol group-containing polysulfide used (average number of thiol groups) may be, for example, 1.1 or more, 1.3 or more, 1.5 or more, 1.8 or more, 2 or more, or more than 2. The upper limit of the average number of thiol groups is not particularly limited, and from the viewpoint of the flexibility of the cured product, for example, it may be 15 or less, 10 or less, 7 or less, or 5 or less. It should be noted that a polysulfide having an average number of thiol groups of 2 or more may also be understood as a thiol compound (C) having 2 or more thiol groups per molecule.

[0097] The above-mentioned thiol group is preferably arranged at the end of the thiol group-containing polysulfide. By reacting such a thiol group-containing polysulfide with an epoxy compound having two or more epoxy groups in one molecule, an epoxy group-containing polysulfide polymer having an epoxy group at the end can be appropriately formed. The thiol group-containing polysulfide used may be one having a thiol group at one end of the main chain, one having a thiol group at both ends of the main chain, one having a thiol group at a position other than the end of the main chain, or a mixture of any combination thereof. It is particularly preferred to use a thiol group-containing polysulfide having a thiol group at both ends of the main chain, i.e., a two-terminal thiol polysulfide. If a sealant sheet containing a polysulfide polymer (A) synthesized using a two-terminal thiol polysulfide is used, there is a tendency to form a cured product that balances strength and elongation well. In some embodiments, the proportion of the terminal thiol polysulfide in the total thiol group-containing polysulfide used can be, for example, more than 50%, more than 70%, more than 90%, more than 95%, more than 98%, or substantially 100% by weight.

[0098] The double-terminal thiol polysulfide is preferably represented by the following general formula (3).

[0099] HS-(R 1 -OR 2 -OR 3 -SS) n R 1 -OR 2 -OR 3 -SH (3)

[0100] In the general formula (3), R 1 , R 2 , R 3 Each independently represents an alkylene group having 1 to 4 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms, and more preferably an alkylene group having 1 to 2 carbon atoms. n in the general formula (3) may be an integer selected so that the formula weight of the compound of the general formula (3) is, for example, 500 or more and 10,000 or less, or 800 or more and less than 9,000, or 1,000 or more and less than 8,000, or more than 1,000 and less than 8,000, or more than 2,000 and less than 7,500.

[0101] In some embodiments, as the compound represented by the general formula (3), for example, R 1 C 2 H 4 , R 2 CH 2 , R 3 C 2 H 4In this embodiment, n in the general formula (3) may be, for example, 3 to 70, 5 to 60, 7 to 50, or 10 to 50.

[0102] (Epoxy-containing polysulfide polymer (AB))

[0103] In the sealant sheet disclosed herein, the sealant sheet of type (I) above may be a sealant sheet comprising an epoxy-containing polysulfide polymer (AB) having two or more epoxy groups in one molecule as the polysulfide polymer (A), and further comprising a thiol compound (C) having two or more thiol groups in one molecule. In some preferred embodiments, the sealant sheet may further comprise a photobase generator (D). The sealant sheet of the above form may further comprise a polysulfide polymer (A) that is not an epoxy-containing polysulfide polymer (AB), or it may not comprise it. In addition, the sealant sheet of the above embodiment may further comprise an epoxy compound (B) that is not an epoxy-containing polysulfide polymer (AB), or it may not comprise it.

[0104] The average value of the number of epoxy groups per molecule of the epoxy-containing polysulfide polymer (AB) (hereinafter, also referred to as the average number of epoxy groups) may be, for example, about 2 or more and about 20 or less. From the viewpoint of the flexibility of the cured product, the average number of epoxy groups may be, for example, 15 or less, 10 or less, 7 or less, or 5 or less. In some embodiments, the average number of epoxy groups may be 4 or less, or 3 or less. In addition, the average number of epoxy groups is typically 2 or more, and from the viewpoint of curability and the strength of the cured product, it may exceed 2, or may be 2.5 or more. In some embodiments, the average number of epoxy groups may be, for example, 3 or more, or 4 or more.

[0105] The epoxy group contained in the epoxy-containing polysulfide polymer (AB) is preferably arranged at the end of the epoxy-containing polysulfide polymer (AB). With such an epoxy-containing polysulfide polymer (AB), there is a tendency to form a cured product with good elongation. The sealant sheet disclosed herein may include an epoxy-containing polysulfide polymer (AB) having two or more epoxy groups at one end of the main chain, may include an epoxy-containing polysulfide polymer (AB) having one or more epoxy groups at both ends of the main chain, or may include both. The epoxy-containing polysulfide polymer (AB) having an epoxy group at one end of the main chain may have a functional group other than an epoxy group at a terminal different from the terminal having the epoxy group. The functional group other than the epoxy group may be, for example, a thiol group, an amino group, a hydroxyl group, etc. The sealant sheet disclosed herein preferably includes at least an epoxy-containing polysulfide polymer (AB) having an epoxy group at both ends of the main chain. By including the epoxy-containing polysulfide polymer (AB) of the structure, there is a tendency to form a cured product that balances strength and elongation in a good balance. For example, an epoxy-group-containing polysulfide polymer (AB) having one epoxy group at each of the two ends of the main chain can be preferably used.

[0106] The epoxy group-containing polysulfide polymer (AB) can be obtained, for example, by reacting the above-mentioned thiol group-containing polysulfide with an epoxy compound having two or more epoxy groups in one molecule in such a manner that the amount of epoxy groups becomes excessive. The above-mentioned epoxy compound may be a bifunctional epoxy compound having two epoxy groups in one molecule, or may be a multifunctional epoxy compound having three or more epoxy groups in one molecule. The epoxy compound may be used alone or in combination of two or more. From the viewpoint of operability when reacting with the thiol group-containing polysulfide, in some embodiments, an epoxy compound that is liquid at room temperature may be preferably used.

[0107] Examples of the bifunctional epoxy compound include bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin (i.e., an epoxy compound having a structure in which the aromatic ring of the bisphenol A epoxy resin is converted into a cycloalkyl ring by hydrogenation), hydrogenated bisphenol F epoxy resin, biphenyl epoxy resin, aliphatic epoxy resin (e.g., polypropylene glycol epoxy resin, etc.), 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, etc., but are not limited to these.

[0108] As the polyfunctional epoxy compound, there can be cited novolac epoxy resin, glycidylamine epoxy resin, biphenyl epoxy resin, triphenylmethane epoxy resin, dicyclopentadiene epoxy resin, glycerol epoxy resin, trimethylolpropane epoxy resin, N,N,N',N'-tetraglycidyl metaphenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, polyglycerol polyglycidyl ether, etc., but it is not limited to these. The number of epoxy groups contained in one molecule of the polyfunctional epoxy compound is at least 3 or more, and can be 4 or more, or 5 or more. In addition, the number of epoxy groups contained in one molecule of the polyfunctional epoxy compound is usually 10 or less, which is appropriate, and can be 8 or less, or 6 or less.

[0109] In some embodiments, a bifunctional epoxy compound can be preferably used as the epoxy compound. The use of a bifunctional epoxy compound is advantageous for obtaining a sealant sheet that provides a cured product showing appropriate elongation. The bifunctional epoxy compound can be used alone or in combination of two or more.

[0110] In some embodiments, as the above-mentioned bifunctional epoxy compound, an epoxy compound containing a carbon ring structure of more than 5-membered rings in the molecule can be preferably used. The sealant sheet formed by using the bifunctional epoxy compound of the structure tends to form a cured product with high strength and good elongation. The above-mentioned carbon ring structure of more than 5-membered rings can be, for example, a benzene ring, a naphthalene ring, a cyclohexyl ring, etc. Examples of epoxy compounds containing the carbon ring structure include bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, biphenyl epoxy resin, etc. In some preferred embodiments, bisphenol F epoxy resin can be used as the above-mentioned bifunctional epoxy compound.

[0111] As the epoxy compound, one or more polyfunctional epoxy compounds may be used in combination with a bifunctional epoxy compound or in place of a bifunctional epoxy resin. By using a polyfunctional epoxy compound, the strength of the cured product can be increased. By using a bifunctional epoxy compound and a polyfunctional epoxy compound in combination, a sealant sheet having a cured product having both strength and elongation at a higher level can be provided.

[0112] In some embodiments, as the above-mentioned multifunctional epoxy compound, a multifunctional epoxy compound having a repeating unit containing an epoxy group (i.e., a polymer type) can be used, for example, a novolac type epoxy resin can be preferably used. Examples of the above-mentioned novolac type epoxy resin include phenol novolac type epoxy resin and o-cresol novolac type epoxy resin. The use of a novolac type epoxy resin is advantageous for obtaining a sealant sheet that provides a cured product with high strength and good elongation. By using a novolac type epoxy resin with a lower molecular weight, there is a tendency for the elongation of the cured product to increase. For example, a phenol novolac type epoxy resin that is liquid at room temperature can be preferably used.

[0113] When the thiol group-containing polysulfide reacts with an epoxy compound having two or more epoxy groups in one molecule, any appropriate catalyst may be used within the range that does not significantly impair the effects obtained by the technology disclosed herein. For example, a known basic catalyst such as 2,4,6-triaminomethylphenol, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene may be appropriately selected and used.

[0114] The amount of alkaline catalyst used is not particularly limited, and can be set in a manner that appropriately exerts the catalytic function. In some embodiments, the amount of alkaline catalyst used, relative to the total amount of 100 parts by weight of thiol-containing polysulfide and epoxy compounds having two or more epoxy groups in one molecule, can be set to, for example, 1 part by weight or less, and it is usually appropriate to set it to 0.5 parts by weight or less, and it can be set to 0.2 parts by weight or less, and it can be set to 0.1 parts by weight or less, and it can also be set to 0.08 parts by weight or less. From the viewpoint of improving the preservation of the sealant sheet, it is advantageous that the amount of alkaline catalyst is not too much. From the viewpoint of the above, the amount of alkaline catalyst relative to the above-mentioned total amount of 100 parts by weight can be set to, for example, 0.07 parts by weight or less, 0.05 parts by weight or less, 0.03 parts by weight or less, or 0.02 parts by weight or less. The lower limit of the amount of alkaline catalyst relative to the above-mentioned total amount of 100 parts by weight is not particularly limited, for example, it can be set to more than 0.001 parts by weight, and it can also be set to more than 0.005 parts by weight.

[0115] The above reaction can be carried out by mixing a thiol-containing polysulfide, an epoxy compound having two or more epoxy groups in one molecule, and a catalyst used as needed in a suitable reaction vessel. In some preferred embodiments, a thiol-containing polysulfide, a bifunctional epoxy compound, a multifunctional epoxy compound, and a catalyst (e.g., a basic catalyst) are mixed in a suitable reaction vessel. The supply method and mixing order of each material to the reaction vessel are not particularly limited and can be selected in a manner to form a suitable reaction product. The conditions of the above reaction can be appropriately set within the range that does not significantly impair the effect obtained by the technology disclosed herein. In some embodiments, the above reaction can be carried out at a reaction temperature of, for example, 0°C to 120°C, preferably 5°C to 120°C, and more preferably 10°C to 120°C. Considering the controllability and reaction efficiency of the reaction, in some embodiments, the above reaction temperature can be, for example, 20°C to 100°C, 30°C to 100°C, 40°C to 100°C, or 60°C to 100°C. The reaction time is not particularly limited, and can be selected from the range of, for example, 10 minutes to 720 hours (preferably 1 hour to 240 hours).

[0116] In some embodiments, the above reaction can be carried out by, for example, sequentially carrying out a first heating step at a temperature of 60°C to 120°C (preferably 70°C to 110°C) and a second heating step at a temperature of 40°C to 80°C (preferably 50°C to 70°C). By carrying out the heating steps in stages like this, it is possible to suppress the elastic modulus of the polysulfide reaction product from becoming too high, and the mixing (e.g., kneading) step of the above reaction product with the additive components such as fillers can be carried out efficiently. The second heating step is preferably carried out at a temperature lower than that of the first heating step. The heating time in the first heating step can be set to, for example, 10 minutes or more, usually 30 minutes or more is appropriate, and can also be set to 1 hour or more. In some preferred embodiments, the heating time in the first heating step can be selected from the range of 10 minutes to 24 hours (preferably 30 minutes to 12 hours, more preferably 1 hour to 6 hours). The heating time in the second heating step can be set to, for example, 3 hours or more, usually 6 hours or more is appropriate, and can also be set to 24 hours or more. In some preferred embodiments, the heating time in the second heating process can be selected from the range of 3 hours to 720 hours (preferably 48 hours to 500 hours, more preferably 72 hours to 300 hours). The heating time in the second heating process is preferably longer than the heating time in the first heating process. It should be noted that the heating process can be divided into three or more stages to be carried out in stages.

[0117] In the synthesis of the epoxy-containing polysulfide polymer (AB) based on the above reaction, the ratio of the thiol-containing polysulfide to the epoxy compound can be set so that the ratio of the total number of epoxy groups contained in the epoxy compound to the total number of thiol groups contained in the thiol-containing polysulfide, that is, the equivalent ratio of epoxy groups / thiol groups (hereinafter also referred to as epoxy / thiol ratio) is greater than 1. In some embodiments, the epoxy / thiol ratio can be, for example, 1.05 or more, or 1.1 or more. From the viewpoint of improving the strength of the cured product, in some embodiments, the epoxy / thiol ratio can be, for example, more than 1.2, more than 1.4, more than 1.5, or more than 1.7. In addition, the epoxy / thiol ratio can be, for example, less than 7.0, less than 5.0, less than 4.5, or less than 4.0. In some embodiments, from the viewpoint of improving the elongation of the cured product, the epoxy / thiol ratio may be, for example, less than 3.5, less than 3.2, less than 3.0, less than 2.5, less than 2.0, or less than 1.8.

[0118] In the synthesis of the epoxy-containing polysulfide polymer (AB) based on the above reaction, the amount of the epoxy compound having two or more epoxy groups in one molecule is not particularly limited. The amount of the epoxy compound can be set, for example, in a manner to achieve the above-mentioned arbitrary epoxy / thiol ratio. In some embodiments, the amount of the epoxy compound can be set to, for example, 1 part by weight or more, and it is usually appropriate to set it to 3 parts by weight or more, and it can be 5 parts by weight or more, or it can be 7 parts by weight or more. In addition, the amount of the epoxy compound can be set to, for example, 50 parts by weight or less, and it is usually appropriate to set it to 30 parts by weight or less, and it can be 20 parts by weight or less, or it can be 15 parts by weight or less, relative to 100 parts by weight of the thiol-containing polysulfide.

[0119] (Thiol group-containing polysulfide polymer (AC))

[0120] In the sealant sheet disclosed herein, the sealant sheet of type (II) may be a sealant sheet comprising a thiol group-containing polysulfide polymer (AC) having two or more thiol groups in one molecule as the polysulfide polymer (A), and further comprising an epoxy compound (B) having two or more thiol groups in one molecule. In some preferred embodiments, the sealant sheet may further comprise a photobase generator (D). The sealant sheet of the above form may further comprise a polysulfide polymer (A) that is not a thiol group-containing polysulfide polymer (AC), or it may not comprise it. In addition, the sealant sheet of the above embodiment may further comprise a thiol compound (C) that is not a thiol group-containing polysulfide polymer (AC), or it may not comprise it.

[0121] The average number of thiol groups of the thiol group-containing polysulfide polymer (AC) is typically 2 or more, and may exceed 2. The upper limit of the average number of thiol groups is not particularly limited, but from the viewpoint of the flexibility of the cured product, it is usually appropriately 10 or less, and may be 7 or less, 5 or less, 4 or less, 3 or less, 2.8 or less, or 2.4 or less.

[0122] The thiol group contained in the thiol group-containing polysulfide polymer (AC) is preferably arranged at the terminal of the thiol group-containing polysulfide polymer (AC). Such a thiol group-containing polysulfide polymer (AC) tends to form a cured product with good elongation. Preferably, the thiol group-containing polysulfide polymer (AC) has one or more thiol groups at both ends of the main chain, and more preferably, the thiol group-containing polysulfide polymer (AC) has one thiol group at both ends of the main chain. By including the thiol group-containing polysulfide polymer (AC) of the above structure, there is a tendency to form a cured product that has both strength and elongation in a good balance.

[0123] As the above-mentioned thiol group-containing polysulfide polymer (AC), for example, a thiol compound having two or more thiol groups in one molecule can be used, which is obtained by reacting the above-mentioned epoxy-containing polysulfide polymer (AB) with a thiol compound having two or more thiol groups in one molecule in such a way that the amount of thiol groups becomes excessive. The above-mentioned thiol compound can be a bifunctional thiol compound having two thiol groups in one molecule, or a polyfunctional thiol compound having three or more thiol groups in one molecule. The thiol compound can be used alone or in combination of two or more. From the viewpoint of obtaining a sealant sheet that provides a cured product showing appropriate elongation, a bifunctional thiol compound can be preferably used. For example, among the thiol compounds reacted with the epoxy group of the epoxy-containing polysulfide polymer (AB), 50% by weight or more, 70% by weight or more, or 90% by weight or more can be a bifunctional thiol compound. Only a bifunctional thiol compound can be used as the above-mentioned thiol compound.

[0124] As the thiol compound to be reacted with the epoxy group-containing polysulfide polymer (AB), for example, one or more selected from the materials that can be used as the thiol compound (C) described later can be used. The reaction of the epoxy group-containing polysulfide polymer (AB) and the thiol compound can be carried out in the same manner as the reaction of the thiol group-containing polysulfide and the epoxy compound described above.

[0125] In the synthesis of the thiol-containing polysulfide polymer (AC) based on the above reaction, the ratio of the epoxy-containing polysulfide used to the thiol compound can be set so that the total number of thiol groups contained in the thiol compound relative to the total number of epoxy groups contained in the epoxy-containing polysulfide, that is, the epoxy / thiol ratio is less than 1. From the viewpoint of improving the strength of the cured product, in some embodiments, the epoxy / thiol ratio can be, for example, 0.95 or less, 0.9 or less, or 0.85 or less. In addition, the epoxy / thiol ratio can be, for example, 0.1 or more, and it is generally appropriate to set it to 0.2 or more. In some embodiments, from the viewpoint of improving the elongation of the cured product, the epoxy / thiol ratio can be, for example, 0.3 or more, 0.5 or more, or 0.6 or more, or 0.7 or more.

[0126] In the synthesis of the thiol-containing polysulfide polymer (AC) based on the above reaction, the amount of the thiol compound having two or more thiol groups in one molecule is not particularly limited. The amount of the thiol compound can be set, for example, in a manner to achieve the above-mentioned arbitrary epoxy / thiol ratio. In some embodiments, the amount of the thiol compound can be set to, for example, 1 part by weight or more, usually 3 parts by weight or more is appropriate, and can be 5 parts by weight or more, or 7 parts by weight or more, relative to 100 parts by weight of the epoxy-containing polysulfide. In addition, the amount of the thiol compound can be set to, for example, 50 parts by weight or less, usually 30 parts by weight or less is appropriate, and can be 20 parts by weight or less, or 15 parts by weight or less, relative to 100 parts by weight of the epoxy-containing polysulfide.

[0127] As the thiol group-containing polysulfide polymer (AC) in the type (II) sealant sheet, for example, the thiol group-containing polysulfide (preferably a polysulfide containing thiol groups at both ends) described above as a material usable as a precursor of the polysulfide polymer (A) can be used.

[0128] <Epoxy Compound (B)>

[0129] In some embodiments, the sealant sheet contains an epoxy compound (B). As the epoxy compound (B) contained in the sealant sheet, a compound having two or more epoxy groups in one molecule can be used without particular limitation. For example, one or more selected from the group consisting of various bifunctional epoxy compounds and polyfunctional epoxy compounds exemplified as materials that can be used in the preparation of the epoxy-containing polysulfide polymer (AB) can be used.

[0130] Considering the balance between the storage property of the sealant sheet before use and the curability during use, it is preferred to use an epoxy compound (B) having an epoxy equivalent in the range of 50 g / eq or more and 600 g / eq or less. The epoxy equivalent may be, for example, 100 g / eq or more, 120 g / eq or more, or 150 g / eq or more, or, for example, 400 g / eq or less, 300 g / eq or less, or 200 g / eq or less. As the epoxy equivalent increases, the storage property before use increases, while the curability during use tends to decrease. When using two or more epoxy compounds (B), it is preferred that the sum of the products of the epoxy equivalent and the weight fraction of each epoxy compound (B) is within the above range. It should be noted that the epoxy equivalent refers to the number of grams of a compound containing 1 equivalent of an epoxy group, which can be measured according to JIS K7236:2001. Alternatively, the nominal values ​​described in catalogs, documents, etc. can be used.

[0131] The average number of epoxy groups of the epoxy compound (B) may be, for example, about 2 or more and about 10 or less. From the viewpoint of the flexibility of the cured product, the average number of epoxy groups may be, for example, 7 or less, 5 or less, 4 or less, or less than 4. In some embodiments, the average number of epoxy groups may be 3 or less, 2.5 or less, or 2.2 or less. As the epoxy compound (B), only one or more bifunctional epoxy compounds may be used. With the above-described configuration, it is easy to obtain a sealant sheet that provides a cured product that exhibits appropriate elongation.

[0132] <Thiol compound (C)>

[0133] In some embodiments, the sealant sheet contains a thiol compound (C). As the thiol compound (C) contained in the sealant sheet, a compound having two or more thiol groups in one molecule can be used without particular limitation. For example, trimethylolpropane trithiopropionate (also known as trimethylolpropane tris (3-mercaptopropionate)), pentaerythritol tetrathiopropionate, ethylene glycol bisthioacetate, 1,4-butanediol bisthioacetate, trimethylolpropane trimercaptoacetate, pentaerythritol tetrathioacetate, di (2-mercaptoethyl) ether, 1,4-butanedithiol, 1,5-dimercapto-3-thiopentane, 1 ,8-dimercapto-3,6-dioxaoctane, 1,3,5-trimercaptomethylbenzene, 4,4'-thiodiphenylthiol, 1,3,5-trimercaptomethyl-2,4,6-trimethylbenzene, 2,4,6-trimercapto-s-triazine, 2-dibutylamino-4,6-dimercapto-s-triazine, pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexa-3-mercaptopropionate, etc., but are not limited to these.

[0134] Commercially available products of the thiol compound (C) include, for example, JER Metal QX11, QX12, JER Cure QX30, QX40, QX60, QX900, and Capcure CP3-800 manufactured by Mitsubishi Chemical Corporation; OTG, EGTG, TMTG, PETG, 3-MPA, TMTP, and PETP manufactured by Yodo Chemical Co., Ltd.; TEMPIC, TMMP, PEMP, PEMP-II-20P, and DPMP manufactured by Sakai Chemical Co., Ltd.; Karenz MTPE1, Karenz MTBD1, Karenz MTNR1, TPMB, and TEMB manufactured by Showa Denko K.K., etc., but are not limited thereto. Each of these compounds may be used alone, or two or more thereof may be used in combination.

[0135] The average number of thiol groups of the thiol compound (C) may be, for example, about 2 or more and about 10 or less. From the viewpoint of the flexibility of the cured product, the average number of thiol groups may be, for example, 7 or less, 5 or less, 4 or less, or less than 4. In some embodiments, the average number of thiol groups may be 3 or less, 2.5 or less, or 2.2 or less. As the thiol compound (C), only one or two or more bifunctional thiol compounds may be used. With the above-mentioned configuration, it is easy to obtain a sealant sheet that provides a cured product that exhibits appropriate elongation.

[0136] As the thiol compound (C), a compound having a primary thiol group (hereinafter, also referred to as a primary thiol compound), a compound having a secondary thiol group (secondary thiol compound), and a compound having a tertiary thiol group (tertiary thiol compound) can be used. From the viewpoint of curability during use of the sealant sheet, a primary thiol compound can be preferably used. In addition, from the viewpoint of controlling the curing speed of the sealant sheet before use and preservability, a secondary or higher thiol compound (i.e., a secondary thiol compound and / or a tertiary thiol compound) can be preferably used. It should be noted that, hereinafter, a thiol compound having two primary thiol groups in one molecule is sometimes referred to as a primary bifunctional thiol compound, and a thiol compound having two secondary thiol groups in one molecule is sometimes referred to as a secondary bifunctional thiol compound.

[0137] In some embodiments, as the thiol compound (C), a primary thiol compound and a secondary or higher thiol compound (for example, a secondary thiol compound) can be used in combination. According to the embodiment, the storage property of the sealant sheet before use and the curability during use can be appropriately taken into account. The weight ratio of the primary thiol compound in the total weight of the primary thiol compound and the secondary or higher thiol compound is not particularly limited, and can be, for example, 5% by weight or more, preferably 15% by weight or more, more preferably 25% by weight or more, and can be 35% by weight or more. In addition, for example, it can be 95% by weight or less, preferably 75% by weight or less, and can be 60% by weight or less, and can also be 45% by weight or less.

[0138] As a thiol compound (C), considering the balance between the storage property of the sealant sheet before use and the curability during use, it is preferred to use a thiol equivalent in the range of 45g / eq or more and 450g / eq or less. The above-mentioned thiol equivalent can be, for example, 60g / eq or more, 70g / eq or more, or 80g / eq or more. In addition, for example, it can be 350g / eq or less, 250g / eq or less, 200g / eq or less, or 150g / eq or less. There is a tendency that the storage property before use is improved and the curability during use is reduced as the thiol equivalent becomes larger. When using two or more thiol compounds (C), it is preferred that the sum of the product of the thiol equivalent and the weight fraction of each thiol compound (C) is in the above range. It should be noted that the thiol equivalent refers to the number of grams of a compound containing 1 equivalent of a thiol group, which can be measured by iodine titration. Alternatively, the nominal value recorded in a catalog, literature, etc. can be used.

[0139] In each of the sealant sheets of type (I) and type (II) disclosed herein, the ratio of the equivalent of the epoxy group that can be contained in the sealant sheet to the equivalent of the thiol group, that is, the epoxy / thiol ratio of the sealant sheet is not particularly limited. The epoxy / thiol ratio of the sealant sheet can be, for example, about 0.1 or more and 10 or less, 0.2 or more and 5 or less, 0.3 or more and 3 or less, or 0.5 or more and 2 or less. By making the epoxy / thiol ratio above any lower limit and below the upper limit, there is a tendency to form a cured product that balances strength and elongation well. In some embodiments, the epoxy / thiol ratio can be, for example, 0.6 or more, 0.7 or more, or 0.8 or more, and can be 1.7 or less, 1.5 or less, or 1.2 or less.

[0140] In the sealant sheet of type (I), the amount of the thiol compound (C) that can be contained in the sealant sheet is not particularly limited. The amount of the thiol compound (C) contained in the sealant sheet can be set, for example, in a manner to achieve the above-mentioned arbitrary epoxy / thiol ratio. In some embodiments, the amount of the thiol compound (C) relative to 100 parts by weight of the epoxy-containing polysulfide polymer (AB) can be, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.3 parts by weight or more, or 0.5 parts by weight or more, and, for example, can be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight or less.

[0141] In the sealant sheet of type (II), the amount of the epoxy compound (B) that can be contained in the sealant sheet is not particularly limited. The amount of the epoxy compound (B) contained in the sealant sheet can be set, for example, in a manner to achieve the above-mentioned arbitrary epoxy / thiol ratio. In some embodiments, the amount of the epoxy compound (B) relative to 100 parts by weight of the thiol group-containing polysulfide polymer (AC) can be, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, or 1 part by weight or more, and, for example, can be 15 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less.

[0142] <Photoreaction catalyst>

[0143] The photocurable sealant sheet disclosed herein preferably contains one or more photoreaction catalysts that can initiate and promote the curing reaction based on light irradiation. Such photoreaction catalysts can be called photoreaction initiators or photopolymerization initiators. As a suitable example of the photoreaction catalyst, a photobase generator (D) can be cited.

[0144] <Photobase Generator (D)>

[0145] In some preferred embodiments, the sealant sheet contains a photobase generator (D). As the photobase generator (D), a substance that generates a base by light irradiation is used. Examples of the photobase generator include α-aminoacetophenone compounds; oxime ester compounds; compounds having substituents such as acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, nitrobenzyl carbamates, and alkoxybenzyl carbamates; compounds having biguanide-type cations; and the like. As the α-aminoacetophenone compound, one having two or more nitrogen atoms is particularly preferred. The photobase generator may be used alone or in combination of two or more.

[0146] As the photobase generator, a commercially available product can be used. Examples of commercially available photobase generators include WPBG-018 (9-anthrylmethyl N,N'-diethylcarbamate), WPBG-027 ((E)-1-[3-(2-hydroxyphenyl)-2-acryloyl]piperidine), WPBG-082 (2-(3-benzoylphenyl)guanidine propionate), WPBG-140 (1-(anthraquinone-2-yl)ethyl)pyrrolidone, and WPBG-141 (1-(anthraquinone-2-yl)ethyl)pyrrolidone. imidazole carboxylate), WPBG-266 (2-(3-benzoylphenyl) propionic acid 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidine), WPBG-300 (n-butyltriphenylboronic acid 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanide), WPBG-345 (tetrakis(3-fluorophenyl)boronic acid 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanide), etc.

[0147] Among these, ionic photobase generators having biguanide-type cations are preferred from the perspective that the base generated by light irradiation can effectively promote the anion addition reaction of epoxy groups and thiol groups. Examples of biguanide-type cations include alkylbiguanides, cycloalkylbiguanides, cycloalkyl-alkylbiguanides, and the like. The anions paired with the biguanide-type cations in the photobase generator may be, for example, borate-based anions. Commercially available products of such photobase generators include the above-mentioned WPBG-300, WPBG-345, and the like. Other examples of anions paired with biguanide-type cations in the photobase generator include carboxylate-based anions. Commercially available products of such photobase generators include, for example, the above-mentioned WPBG-266.

[0148] The amount of the photobase generator used can be set so as to obtain the desired effect. In some embodiments, the amount of the photobase generator used can be, for example, 0.01 parts by weight or more, and preferably 0.03 parts by weight or more, 0.07 parts by weight or more, or 0.1 parts by weight or more, based on 100 parts by weight of the total amount of the epoxy-containing polysulfide polymer (AB) and the thiol compound (C) (in the case of the (I) type sealant sheet) or the total amount of the thiol-containing polysulfide polymer (AC) and the epoxy compound (B) (in the case of the (II) type sealant sheet). In addition, from the viewpoint of raw material cost, the amount of the photobase generator used is usually preferably 3 parts by weight or less, more preferably 2 parts by weight or less, and can be 1 part by weight or less, 0.7 parts by weight or less, 0.5 parts by weight or less, or 0.3 parts by weight or less, based on 100 parts by weight of the total amount.

[0149] <Photosensitizer>

[0150] The sealant sheet disclosed herein may contain a sensitizer. By using a sensitizer, the utilization efficiency of the irradiated light and the sensitivity of the photoreaction catalyst (such as a photobase generator (D)) can be improved. The photosensitizer can be appropriately selected from known materials for use. Non-limiting examples of photosensitizers include benzophenone, 4-methylbenzophenone, 3-benzoylbiphenyl, 4-(4-methylphenylthio)benzophenone, methyl 2-benzoylbenzoate, 4-phenylbenzophenone, 4,4'-bis(dimethoxy)benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 2-benzoylbenzoic acid methyl ester, 2-methyl Benzophenone derivatives such as benzoyl benzophenone, 3-methylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone; thioxanthone, xanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 1-chloro-4-propoxythioxanthone, 2,4-diethylthioxanthone 9-one and other thioxanthone derivatives; 2-hydroxy-9-fluorenone and other fluorene compounds; anthraquinone derivatives such as anthraquinone, dibenzocycloheptenone, 2-amino-9-fluorenone; anthraquinone derivatives such as anthraquinone, 2-ethylanthraquinone, 2-hydroxyanthraquinone, 2-aminoanthraquinone; 1-methylnaphthalene, 2-methylnaphthalene, 1-fluoronaphthalene, 1-chloronaphthalene, 2-chloronaphthalene, 1-bromonaphthalene, 2-bromonaphthalene, 1-iodonaphthalene, 2-iodonaphthalene, 1-naphthol, 2-naphthol, 1- Naphthalene derivatives such as methoxynaphthalene, 2-methoxynaphthalene, 1,4-dicyanonaphthalene, and methyl 3-hydroxy-2-naphthoate; anthracene derivatives such as anthracene, 1,2-benzanthracene, 9,10-dichloroanthracene, 9,10-dibromoanthracene, 9,10-diphenylanthracene, 9-cyanoanthracene, 9,10-dicyanoanthracene, and 2,6,9,10-tetracyanoanthracene; nitro compounds such as nitrobenzoic acid and nitroaniline; various pigments; etc., but are not limited to these.

[0151] The amount of photosensitizer used can be set in a manner to obtain the desired sensitization effect. In some embodiments, the amount of photosensitizer used can be, for example, 0.001 parts by weight or more, 0.005 parts by weight or more, 0.01 parts by weight or more, or 0.05 parts by weight or more relative to 100 parts by weight of the total amount of epoxy compound (B) and thiol compound (C). There is no particular limit on the upper limit of the amount of photosensitizer used. From the perspective of controlling the curing speed and storage of the sealant sheet, it is usually appropriate to be less than 10 parts by weight, and it can be less than 5 parts by weight, less than 1 part by weight, less than 0.5 parts by weight, or less than 0.3 parts by weight.

[0152] <Storage Stabilizer>

[0153] The sealant sheet disclosed herein may also contain any compound that can contribute to the inhibition of the photocuring reaction within the limit that other characteristics are not greatly impaired. By using the compound, the preservation of the sealant sheet before use can be improved. The storage stabilizer can be, for example, an organic acid, an inorganic acid, and an oligomer, a polymer, a borate ester, or a phosphate ester that is liquid or solid at room temperature, and contains an acidic group in the molecule, and may have a functional group other than the acidic group. For example, sulfuric acid, acetic acid, adipic acid, tartaric acid, fumaric acid, barbituric acid, boric acid, pyrogallol, phenolic resin, carboxylic anhydride, etc. can be cited, but are not limited to these. The storage stabilizer can be used alone or in combination of two or more. The amount of the storage stabilizer is not particularly limited and can be set in a manner to obtain the desired effect.

[0154] Preferred examples of the storage stabilizer include borate esters and phosphoric acid esters.

[0155] Borates are borate esters that are liquid or solid at room temperature. Examples include trimethyl borate, triethyl borate, tri-n-propyl borate, tri-isopropyl borate, tri-n-butyl borate, tripentyl borate, triallyl borate, trihexyl borate, tricyclohexyl borate, trioctyl borate, trinonyl borate, tridecyl borate, tridodecyl borate, trihexadecyl borate, trioctadecyl borate, tri(2-ethylhexyloxy)borane, bis(1,4,7,10-tetraoxyundecyl)(1,4,7,10,13-pentaoxytetradecyl)(1,4,7-trioxyundecyl)borane, tribenzyl borate, triphenyl borate, tri-o-tolyl borate, tri-m-tolyl borate, triethanolamine borate, etc., but are not limited to these.

[0156] Examples of the phosphoric acid esters include ethyl phosphate, butyl phosphate, propyl phosphate, 2-ethylhexyl phosphate, dibutyl phosphate, di(2-ethylhexyl) phosphate, oleyl phosphate, and ethyl diethyl phosphate, but are not limited thereto.

[0157] <Packing>

[0158] The sealant sheet disclosed herein may be blended with a filler as required. Thus, one or both of the fracture strength and elongation at break of the cured product may be improved. The filler may also contribute to the regulation of the storage modulus of the sealant sheet. In addition, by the appropriate use of the filler, the shape retention and processability of the sealant sheet may be improved. The filler used is not particularly limited, and any appropriate filler may be used within the range that does not significantly impair the effect obtained by the technology disclosed herein. The filler may be used alone or in combination of two or more.

[0159] Examples of materials constituting the filler include, but are not limited to, talc, silica, glass, carbon black, alumina, clay, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, barium sulfate, titanium dioxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, boron nitride, aluminum borate, barium zirconate, calcium zirconate, etc. Among them, preferred examples include talc, silica, glass and calcium carbonate.

[0160] The content of the filler is not particularly limited and can be selected in a manner to obtain appropriate characteristics. The content of the filler can be, for example, 1% or more of the total weight of the sealant sheet, or 5% or more of the total weight. From the perspective of obtaining a higher use effect, it can be 10% or more of the total weight, 15% or more of the total weight, 20% or more of the total weight, or 25% or more of the total weight. In addition, the content of the filler can be, for example, less than 50% by weight of the total weight of the sealant sheet. From the perspective of improving the formability of the sheet shape and the elongation of the cured product, it is usually appropriate to set it to less than 40% by weight, or less than 35% by weight. In some embodiments, the content of the filler can be less than 30% by weight or less than 25% by weight.

[0161] The average particle size of the filler is not particularly limited. It is appropriate that the above average particle size is usually 100 μm or less, preferably 50 μm or less. If the average particle size is small, there is a tendency to improve the effect of improving one or both of the fracture strength and elongation at break of the cured product. In some embodiments, the average particle size of the filler can be, for example, 30 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, or 5 μm or less. In addition, the average particle size of the filler can be, for example, 0.1 μm or more, 0.2 μm or more, 0.5 μm or more, or 1 μm or more. It is advantageous that the average particle size is not too small from the viewpoint of the handleability and dispersibility of the filler.

[0162] In this specification, the average particle size of the filler refers to the particle size at which the cumulative particle size on a volume basis is 50% in a particle size distribution measured by a laser diffraction / scattering method, that is, the 50% volume average particle size (50% median particle size).

[0163] In some embodiments, a filler formed of a material having a refractive index in the range of 1.56 or more and less than 1.62 may be preferably used. For example, a glass filler having a refractive index in the above range may be used. The above refractive index range is a range that is equal to or similar to the refractive index of the polysulfide polymer (A) (typically about 1.60). Therefore, if a filler having a refractive index in the above range is used, there is a tendency that the reduction in the transmittance of the sealant sheet caused by the blending of the filler is suppressed compared to a filler having a refractive index outside the above range. By making the sealant sheet have a certain degree of transmittance, it is easy to observe the sealed object portion through the sealant sheet. This is advantageous from the perspective of positioning when the sealant sheet is arranged at a predetermined position.

[0164] The sealant sheet disclosed herein can be used in combination with a filler (such as a glass filler) having a refractive index in the range of more than 1.56 and less than 1.62 and a filler (such as talc) having a refractive index outside the above range. In this case, the proportion of the filler whose refractive index is in the above range in the total amount of the filler contained in the sealant sheet can be set to, for example, more than 10% by weight, more than 25% by weight, preferably more than 45% by weight, more than 60% by weight, more than 85% by weight, or 100% by weight. In some embodiments, a filler formed by a material having a refractive index in the range of more than 1.56 and less than 1.61 or more than 1.57 and less than 1.60 can be more preferably used. The refractive index can be measured using methods such as the commonly known minimum deflection angle method, the critical angle method, and the V-block method. The determination can be carried out using, for example, a multi-wavelength Abbe refractometer DR-M4 (manufactured by ATAGO Co., Ltd.). Alternatively, the nominal values ​​recorded in the catalog, literature, etc. can be used.

[0165] The sealant sheet disclosed herein may contain other optional components within the range that does not significantly impair the effects obtained by the technology disclosed herein. Examples of such optional components include, but are not limited to, colorants such as dyes and pigments, dispersants, plasticizers, softeners, flame retardants, antioxidants, ultraviolet absorbers, antioxidants, light stabilizers, and the like.

[0166] The sealant sheet disclosed herein may further contain polymers or oligomers other than the above (hereinafter also referred to as arbitrary polymers) for the purpose of improving the adhesion to the sealed object, for example. From the viewpoint of oil resistance of the cured product, the content of the arbitrary polymer is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and further preferably 1 part by weight or less relative to 100 parts by weight of the polysulfide polymer (A). The sealant sheet may be substantially free of the arbitrary polymer. It should be noted that, in this specification, substantially free of a certain component means that at least the component is not intentionally contained unless otherwise specified.

[0167] In the sealant sheet disclosed herein, the content of the organic solvent may be, for example, 5% or less, 2% or less, 1% or less, or 0.5% or less by weight of the sealant sheet, or may be substantially free of the organic solvent. The content of the organic solvent may also be 0%. The organic solvent herein refers to a component that is not intended to react with other components in the sealant sheet (particularly epoxy-containing polysulfide and a curing agent that may be used as needed), such as toluene, cyclohexanone, and trichloroethane.

[0168] The sealant sheet of type (I) may contain a thiol compound (C) (hereinafter also referred to as a low molecular weight thiol compound) having an Mw of 1000 or less, preferably 600 or less, and more preferably 400 or less. The content of the low molecular weight thiol compound may be, for example, 0.1% by weight or more, 0.3% by weight or more, or 0.5% by weight or more of the total amount of the thiol compound (C) and the epoxy-containing polysulfide polymer (AB) on a weight basis. The low molecular weight thiol compound may exhibit a function of increasing the viscosity of the sealant sheet disclosed herein. By increasing the viscosity of the sealant sheet, for example, the temporary fixation of the sealant sheet disposed at the sealing object portion to the sealing object portion is improved. The temporary fixation refers to the property of suppressing the floating and positional displacement of the sealant sheet from the sealing object portion until the sealant sheet disposed at the sealing object portion is cured. The low molecular weight thiol compound reacts by light irradiation and is incorporated into the cured product. In some embodiments, the content of the low molecular weight thiol compound may be less than 0.1% by weight, less than 0.05% by weight, or substantially free of the total amount of the thiol compound (C) and the epoxy-containing polysulfide polymer (AB) on a weight basis. In such an embodiment, the sealant sheet disclosed herein may have adhesiveness on the surface and may be temporarily fixed to the sealing target portion.

[0169] The sealant sheet of type (II) may contain an epoxy compound (B) (hereinafter also referred to as a low molecular weight epoxy compound) having a Mw of 1000 or less, preferably 600 or less, and more preferably 400 or less. The content of the low molecular weight epoxy compound may be, for example, 0.1% by weight or more, 0.3% by weight or more, or 0.5% by weight or more of the total amount of the epoxy compound (B) and the thiol group-containing polysulfide polymer (AC) on a weight basis. The low molecular weight epoxy compound, like the low molecular weight thiol compound, may exhibit a function of improving the viscosity of the sealant sheet disclosed herein. In some embodiments, the content of the low molecular weight epoxy compound may be less than 0.1% by weight, less than 0.05% by weight, or substantially free of the total amount of the epoxy compound (B) and the thiol group-containing polysulfide polymer (AC) on a weight basis. The sealant sheet disclosed herein may also have viscosity on the surface in such an embodiment and may be temporarily fixed to the sealing object.

[0170] <Supporting substrate>

[0171] The sealant sheet disclosed herein may include a supporting substrate. Such a sealant sheet includes: a supporting substrate and a sealing layer disposed on at least one surface (e.g., both surfaces) of the supporting substrate. The sealing layer is composed of a material that can form the above-mentioned sealant sheet. Such a sealant sheet with a supporting substrate tends to have excellent adhesion to the sealed object, excellent processability, and excellent handling properties.

[0172] As non-limiting examples of the material of the supporting substrate, there can be cited various resin films such as polyolefin films formed by polyethylene (PE), polypropylene (PP), etc., polyester films formed by polyethylene terephthalate (PET), fluororesin films formed by polytetrafluoroethylene (PTFE), etc., polyvinyl chloride films, etc.; woven fabrics and non-woven fabrics of various fibrous materials (which can be natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, etc.) alone or based on blends, etc.; etc. It can also be a layered body composed of them. As a supporting substrate, it is preferred to use a supporting substrate containing a resin film that can maintain its shape independently (self-supporting or non-dependent) as a base film. Among them, polyester films such as PET films are preferred. It should be noted that the "resin film" is a non-porous structure, typically referring to a resin film that is substantially free of bubbles (voids). Therefore, the above-mentioned resin film is a concept that is distinguished from foam films and non-woven fabrics. The above-mentioned resin film can be a single-layer structure or a multilayer structure with more than two layers. The resin film may be unstretched or stretched (for example, uniaxially stretched or biaxially stretched).

[0173] The supporting substrate (e.g., resin film) may be mixed with known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, anti-blocking agents, etc. as needed. The amount of the additives is not particularly limited and can be appropriately set according to the application, etc.

[0174] In the structure with a supporting substrate, the transmittance of the supporting substrate may be, for example, more than 5%, more than 10%, more than 15%, or more than 20%. From the viewpoint of curability based on light irradiation, 50% or more is appropriate, preferably more than 70%, and may be more than 90%. The upper limit of the transmittance of the supporting substrate is not particularly limited, and may be 100%. From a practical point of view, it may be less than 80%, less than 60%, or less than 40%. The supporting substrate disclosed herein may also be implemented in a manner with a transmittance of less than 30%, less than 20%, or less than 15%. The above transmittance is measured by the same method as the transmittance measurement method of the sealant sheet.

[0175] The thickness of the supporting substrate is not particularly limited and can be selected according to the purpose of use, the mode of use, etc. The thickness of the supporting substrate can be, for example, about 1000 μm or less, or about 300 μm or less. From the perspective of curability based on light irradiation, about 100 μm or less is appropriate, preferably about 80 μm or less, about 50 μm or less, about 30 μm or less, or 15 μm or less. If the thickness of the supporting substrate becomes smaller, there is a tendency to improve the softness of the sealant sheet and the followability of the surface shape of the sealing object. In addition, from the perspectives of handling and processing, the thickness of the supporting substrate can be, for example, more than 1 μm, more than 2 μm, more than 5 μm, or more than 10 μm. In some ways, the thickness of the supporting substrate is preferably more than 20 μm (for example, more than 25 μm), more preferably more than 30 μm, more than 50 μm, or more than 70 μm.

[0176] <Method for producing sealant sheet>

[0177] Some methods of manufacturing the sealant sheet disclosed herein are described below. However, the following description is for illustrative purposes and does not limit the manufacturing method of the sealant sheet disclosed herein. For example, for ease of description, the following mainly describes the method of using a photobase generator and a filler, but the sealant sheet disclosed herein is not limited to the method containing these components.

[0178] The sealant sheet combination of type (I) comprises an epoxy-containing polysulfide polymer (AB) and a thiol compound (C) (for example, the above-mentioned low molecular weight thiol compound). The sealant sheet of the composition can be produced, for example, by a method comprising the following steps: preparing an epoxy-containing polysulfide polymer (AB); adding a thiol compound (C), a photobase generator (D) and a filler to the above-mentioned epoxy-containing polysulfide polymer (AB) and mixing; and forming the obtained mixture into a sheet shape. In the case where the above-mentioned epoxy-containing polysulfide polymer (AB) is a reaction product of a thiol-containing polysulfide, a bifunctional epoxy compound and a multifunctional epoxy compound, preparing the above-mentioned mixture may sequentially include: preparing a reaction product of a thiol-containing polysulfide, a bifunctional epoxy compound and a multifunctional epoxy compound; and adding a thiol compound (C), a photobase generator (D) and a filler to the reaction product and mixing. Alternatively, the filler may be mixed together when preparing the above-mentioned reaction product.

[0179] The sealant sheet combination of type (II) comprises a thiol group-containing polysulfide polymer (AC) and an epoxy compound (B) (for example, the above-mentioned low molecular weight epoxy compound). The sealant sheet of the composition can be produced, for example, by a method comprising the following steps: preparing a thiol group-containing polysulfide polymer (AC); adding an epoxy compound (B), a photobase generator (D) and a filler to the above-mentioned thiol group-containing polysulfide polymer (AC) and mixing; and forming the obtained mixture into a sheet shape. In the case where the above-mentioned thiol group-containing polysulfide polymer (AC) is a thiol-modified product of an epoxy group-containing polysulfide polymer, preparing the above-mentioned mixture may sequentially include: reacting a thiol group of a compound having two or more thiol groups in one molecule with an epoxy group of the above-mentioned epoxy group-containing polysulfide polymer (AB) to prepare a thiol group-containing polysulfide polymer (AC); adding an epoxy compound (B), a photobase generator (D) and a filler to the above-mentioned thiol group-containing polysulfide polymer (AC) and mixing. Alternatively, the filler may be mixed together when preparing the above-mentioned reaction product.

[0180] Regarding the preparation of the above-mentioned reaction product, the description already described can be applied, and repeated description is omitted. As the device that can be used in the mixing of the above-mentioned reaction product and the added components, for example, closed mixing devices or batch mixing devices such as Banbury mixer, kneader, two-roll mill, three-roll mill can be cited; continuous mixing devices such as single screw extruder, twin screw extruder, but are not limited to these.

[0181] As a method for forming the above-mentioned mixture into a sheet, known sheet forming methods such as press forming, calendaring, and melt extrusion can be used alone or in appropriate combination. The above-mentioned press forming can be normal pressure pressing or vacuum pressing. From the viewpoint of preventing air bubbles from entering the sheet and inhibiting the thermal modification of the above-mentioned mixture, vacuum press forming or calendaring can be preferably applied in some embodiments. The obtained sealant sheet can be formed, for example, by laminating it on a release liner. Figure 1 or Figure 2 Alternatively, the mixture can be coated on a release liner and a supporting substrate using a conventional coating machine such as a gravure roll coater to form a sheet. The sealant sheet with a supporting substrate can be formed into a sealant sheet with a release liner by laminating a release liner on its surface. Thereafter, the sealant sheet can be stored, processed (e.g., cut to a specified width, processed from a roll to a sheet, punched to a specified shape, etc.), and transported in the above-mentioned form.

[0182] <Release liner>

[0183] The photocurable sealant sheet used in the method disclosed herein may be in the form of a sealant sheet with a release liner laminated on its surface. Thus, the surface of the sealant sheet is protected by the release liner, thereby preventing deformation caused by external forces, dust adhesion, and other contamination. In addition, the sealant sheet can be handled in a state laminated on the release liner, and can be attached to the sealed object in a state laminated on the release liner. Such a sealant sheet with a release liner has excellent handling properties and quality retention, and can be easily and accurately arranged at a desired location.

[0184] The release liner is not particularly limited, and includes, for example, a release liner having a release treatment layer on the surface of the release liner substrate; and a release liner formed of a low-adhesive resin film (polyolefin resin film, fluororesin film) such as a fluorine-based polymer (PTFE, etc.) and a polyolefin-based resin (PE, PP, etc.).

[0185] As the release liner disclosed herein, one having a release treatment layer on a release liner substrate can be preferably used. The above-mentioned release treatment layer can be formed by surface treating the release liner substrate with a release treatment agent. The release treatment agent can be a well-known release treatment agent such as a silicone-based release treatment agent, a long-chain alkyl-based release treatment agent, a fluorine-based release treatment agent, and molybdenum (IV) sulfide. In some embodiments, a release liner having a release treatment layer based on a silicone-based release treatment agent can be preferably used. The thickness and formation method of the release treatment layer are not particularly limited, and can be set in a manner that the release surface of the release liner exerts appropriate release properties.

[0186] As the release liner substrate, various plastic films can be preferably used. In this specification, the plastic film is typically a non-porous sheet, and is a concept distinguished from, for example, a non-woven fabric (that is, does not include a non-woven fabric).

[0187] As the material of the above-mentioned plastic film, for example, polyester resins such as PET, polyolefin resins such as PE and PP, etc. can be mentioned. A release liner substrate formed of one of these resins or a mixture of two or more thereof can be used. Among them, as a preferred release liner substrate, a polyester resin film (such as PET film) formed of a polyester resin can be mentioned.

[0188] The plastic film used as the release liner substrate may be any of an unstretched film, a uniaxially stretched film, and a biaxially stretched film. In addition, the plastic film may be a single-layer structure or a multilayer structure including two or more sublayers. The plastic film may be mixed with known additives that can be used in release liner substrates, such as antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, colorants such as pigments and dyes, lubricants, fillers, antistatic agents, and nucleating agents. In the plastic film with a multilayer structure, each additive may be mixed in all sublayers or only in a part of the sublayers.

[0189] In the embodiment in which the first and second release liners are provided on each surface of the sealant sheet, the first release liner and the second release liner may have the same material and configuration, or may have different materials and configurations.

[0190] In the sealant sheet with release liner disclosed herein, the release liner and the sealant sheet are laminated in a releasable manner. Therefore, the release force of the release liner relative to the sealant sheet is preferably limited to a specified value or less. In some preferred embodiments, the release force of the release liner is about 3N / 50mm or less, more preferably 1N / 50mm or less, can be 0.70N / 50mm or less, or can be 0.50N / 50mm or less. It is appropriate that the lower limit of the release force of the release liner is more than 0.01N / 50mm, and from the perspective of protecting the release liner and preventing floating, it can be more than 0.05N / 50mm. The release force of the release liner can be adjusted by stripping the surface of the release liner, etc. In the embodiment in which each side of the sealant sheet has the first and second release liners, the release force of each release liner is preferably different from the perspective of stripping workability, or can also be designed to the same degree.

[0191] The release force of the release liner was measured by preparing a sealant with a release liner cut into a length of 150 mm and a width of 50 mm at 23° C. and 50% RH at a tensile speed of 300 mm / min and a peeling angle of 180°.

[0192] The thickness of the release liner is not particularly limited, and can be, for example, about 10 μm to 500 μm. From the viewpoint of the strength and handling of the release liner, it is appropriate that the thickness of the release liner is 20 μm or more (for example, 25 μm or more), preferably 30 μm or more, 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, or 70 μm or more. A large thickness of the release liner is also advantageous from the viewpoint of preventing deformation of the sealant sheet attached to the sealed object. In addition, from the viewpoint of the handling of the release liner (for example, ease of winding), it is appropriate that the thickness of the release liner is 300 μm or less, preferably 200 μm or less, more preferably 150 μm or less, further preferably 100 μm or less, particularly preferably 80 μm or less, 50 μm or less, or 30 μm or less. When the sealant sheet is attached to the object to be sealed in a state of being laminated on the release liner, the sealant sheet tends to have excellent followability to the surface shape of the sealing object. In the embodiment in which the first and second release liners are provided on each surface of the sealant sheet, the thickness of the first release liner and the second release liner are preferably different from the viewpoint of the peeling workability, or they may be the same.

[0193] The preferred thickness of the release liner can also be defined by the relationship with the thickness of the sealant sheet. R Relative to the thickness T of the sealant sheet S The ratio (T R / T S ), from the viewpoint of efficient photocuring of the sealant sheet, for example, about 1 or less is appropriate, preferably about 0.5 or less, and can be about 0.3 or less. R / T S ) has a tendency to have excellent followability to the surface shape of the sealing object when the sealant sheet is attached to the sealing object in a state of being laminated on the release liner. R / T S The lower limit of ) is, for example, appropriately about 0.01 or more, and is preferably about 0.05 or more from the viewpoint of handling properties, and may be about 0.1 or more, or may be about 0.15 or more.

[0194] The release liner constituting the sealant sheet with release liner used in the method disclosed herein may be light-transmissive or light-shielding. Here, "light-transmissive" in this specification, unless otherwise specified, means that the light transmittance in the wavelength range of 350 to 450 nm is 20% or more, for example, 50% or more. In addition, "light-shielding" in this specification, unless otherwise specified, means that the light transmittance in the wavelength range of 350 to 450 nm is less than 20%, preferably less than 10%. In the embodiment in which each surface of the sealant sheet is provided with the first and second release liners, the light transmittance of the first release liner and the light transmittance of the second release liner may be the same or different.

[0195] The light transmittance of the release liner in the wavelength range of 350 to 450 nm is measured by the method described in Examples below. In this specification, for convenience, the value at a wavelength of 365 nm may be referred to as the light transmittance (wavelength 365 nm) of the release liner.

[0196] The light transmittance of the release liner can be adjusted by the selection of the material (resin material) of the release liner base material, the type and amount of additives (for example, colorants such as pigments), the selection of a release treatment agent, and the like.

[0197] Assuming that the sealant sheet is irradiated with light through the release liner, the transmittance of the release liner in the wavelength region of 350 to 450 nm is preferably 25% or more, more preferably 30% or more, and further preferably 35% or more, and may be 50% or more, 70% or more, 90% or more, 95% or more, or 99% or more, from the viewpoint of the curability of the sealant sheet based on the light irradiation through the release liner. In some embodiments, at least the release liner disposed on the light irradiation side may be one having the above-mentioned transmittance. In a configuration in which each side of the sealant sheet has two release liners, the two release liners may have the above-mentioned transmittance, or only one (the light irradiation side) may have the above-mentioned transmittance. The upper limit of the above-mentioned transmittance is 100%, and it may be less than 100% in practical use.

[0198] In some embodiments, from the viewpoint of visual recognition, it is preferable to use a release liner having a light transmittance of 80% or less. Such a release liner can easily confirm the presence or absence of the release liner on the sealant sheet, for example, and can prevent forgetting to remove the release liner after the sealant sheet is attached to the sealed object. From such a viewpoint, the light transmittance can be, for example, 75% or less, 70% or less, or 65% or less.

[0199] It should be noted that, in this specification, the release liner having the above-mentioned transmittance above the prescribed value means that the main area (more than 50% of the whole, for example, more than 70%) of the whole area laminated with the sealant sheet has the above-mentioned transmittance. Assuming that the sealant sheet is irradiated with light across the release liner, from the viewpoint of uniform and efficient photocuring of the above-mentioned sealant sheet, the release liner preferably has a transmittance above the prescribed value in substantially all areas of the release liner surface. Here, "substantially all areas of the release liner surface" means that, in the surface of the release liner, when the area of ​​the whole area laminated with the sealant sheet is set to 100%, the area ratio of the area that does not have the above-mentioned transmittance due to configurations such as printing is less than 5% of the above-mentioned whole. The area ratio of the area that does not have such the above-mentioned transmittance may be less than 3% or less than 1%. In other embodiments, the ratio of the area of ​​the release liner surface without the above light transmittance to the total area of ​​the area laminated with the sealant sheet can be appropriately set within a range that does not impair the curing of the photocurable sealant sheet (e.g., about 30% or less, and further about 10% or less).

[0200] The sealant sheet with release liner disclosed herein may include a light-shielding release liner as its constituent element. This helps to improve the storage stability of the sealant sheet when it is stored in the form of a sealant sheet with release liner (for example, the inhibition of curing caused by irradiation with light during storage). As the light-shielding release liner, a release liner having a light transmittance in the wavelength range of 350 to 450 nm that is preferably less than 10%, more preferably less than 5%, and further preferably less than 1% can be used. The lower limit of the light transmittance of the light-shielding release liner is 0%, and from a practical point of view, it can be, for example, 0.1% or more.

[0201] When the sealant sheet with a release liner disclosed herein includes a light-transmitting release liner, the release liner preferably has a uniform light transmittance over substantially the entire surface of the release liner in order to uniformly cure the sealant sheet when the sealant sheet is irradiated with light through the release liner. For example, the light transmittance of the entire surface of the release liner in the region laminated with the sealant sheet is preferably within a range of ±10% (e.g., ±5%). Thus, a sealant cured product with no uneven curing can be preferably obtained by irradiating light through the release liner.

[0202] In addition, when the sealant sheet with a release liner disclosed herein includes a light-shielding release liner, the release liner uniformly exerts the effect of improving the storage property of the sealant sheet by light shielding, and therefore preferably has a uniform light transmittance over substantially the entire surface of the release liner. For example, the light transmittance of the entire surface of the release liner in the area laminated with the sealant sheet is preferably within a range of ±10% (e.g., ±5%).

[0203] A release liner having a desired light transmittance can be preferably produced by using an appropriate colorant. As the colorant, conventionally known pigments and dyes can be used. As the pigment, for example, it is preferable to use inorganic pigments such as zinc carbonate, zinc oxide, zinc sulfide, talc, kaolin, calcium carbonate, titanium oxide, silicon dioxide, lithium fluoride, calcium fluoride, barium sulfate, aluminum oxide, zirconium oxide, iron oxide, iron hydroxide, chromium oxide, chromium hydroxide, spinel-type calcined pigments, chromic acid, chrome vermilion, cyanine, cobalt blue, aluminum powder, bronze powder, silver powder, and calcium phosphate, and organic pigments such as phthalocyanine, azo, condensed azo, azo lake, anthraquinone, perinone, flavonoid, indigo, thioindigo, isoindolinone, azomethine, dioxazine, quinacridone, nigrosine, triphenylmethane, and carbon black that can easily achieve a predetermined transmittance. As dyes, for example, azo dyes, anthraquinone, quinophthalone, styryl, diphenylmethane, triphenylmethane, oxazine, triazine, xanthan gum, methane, azomethine, acridine, dioxazine, which are easy to achieve a predetermined transmittance, are preferably used. The colorant can be used alone or in combination of two or more.

[0204] The above light transmittance is achieved by making any layer constituting the release liner (release liner substrate, release treatment layer, or any layer different therefrom) contain an appropriate colorant. In some preferred embodiments, the release liner substrate contains the above colorant.

[0205] Although not particularly limited, the release liner having a light transmittance within the specified range disclosed herein may have a transmittance above the specified range and be in one or more colors selected from, for example, black, gray, white, red, blue, yellow, green, yellow-green, orange, purple, gold, silver, pearl, etc. From the viewpoint of visual recognition, gray, red, blue, yellow, green, yellow-green, orange, and purple are preferred, and from the viewpoint of achieving both transmittance for photocuring and visual recognition, blue and green are more preferred, and blue is particularly preferred.

[0206] It should be noted that in the technology disclosed herein, blue refers to a color having a wavelength region of the visible spectrum of 360 nm or more and less than 480 nm, and green refers to a color having a wavelength region of the visible spectrum of 480 nm or more and less than 560 nm.

[0207] <Purpose (How to use)>

[0208] The material of the part sealed by the technology disclosed herein is not particularly limited. The above-mentioned material can be, for example, metal, resin, or a composite material thereof, and more specifically, can be a metal or semi-metal material such as iron, iron alloy (carbon steel, stainless steel, chrome steel, nickel steel, etc.), aluminum, aluminum alloy, nickel, tungsten, copper, copper alloy, titanium, titanium alloy, silicon, etc.; a resin material such as polyolefin resin, polycarbonate resin, acrylic resin, acrylonitrile resin (PAN); a ceramic material such as alumina, silicon dioxide, sapphire, silicon nitride, tantalum nitride, titanium carbide, silicon carbide, gallium nitride, gypsum, etc.; a glass material such as aluminosilicate glass, soda lime glass, sodium aluminosilicate glass (Soda aluminosilicate glass), quartz glass, etc.; a laminate thereof, a composite thereof, etc. As suitable examples of the above-mentioned metal or semi-metal material, light metals such as aluminum and titanium or alloys with the light metal as the main component can be listed. As an example of an aluminum alloy, duralumin (for example, duralumin A2024, duralumin A2017, etc.) can be listed. Examples of the composite material include carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (FRP), etc. The technology disclosed herein is preferably used for an article or component having a sealing portion made of the above-mentioned material.

[0209] The sealant sheet disclosed herein is in the form of a non-liquid (i.e., solid) sheet in a temperature range of about 25°C, so unlike a liquid sealant, the operator does not need to control the thickness when configuring it to the sealing object. In addition, unlike a liquid sealant, the sealant sheet can be configured to the sealing object after being cut into the desired shape in advance (typically, it is attached by utilizing the viscosity of the sealant sheet). The light irradiation of the sealant sheet can be performed after being cut into the desired shape, or the sealant sheet after light irradiation can be cut into the desired shape using the available time. Alternatively, the sealant sheet in the form of a roll can be attached to the sealing object while being released, and the remaining sealant sheet can be cut off. For example, a light source for light irradiation can be set near the discharge port of the sealant sheet in the form of a roll, so that the sealant sheet released from the roll form is attached to the sealing object after being pre-irradiated with light. By using the sealant sheet disclosed herein, the problems of dripping, uneven coating, overflow, etc. during the application of the liquid sealant can be fundamentally solved, and a significant reduction in the operation time can be achieved.

[0210] It should be noted that the sealant sheet is preferably stored in a dark room or other space (dark place) where light that affects photocuring is blocked or limited until it is used, that is, before the light irradiation step. The sealant sheet during storage may be in the form of a sealant sheet with a release liner (a sheet having a shape suitable for the application, etc.) or a sealant sheet roll with a release liner.

[0211] The sealant sheet disclosed herein is cured by light irradiation. Although not particularly limited, if some preferred methods are cited as examples, light irradiation is performed so that a base is generated by the photobase generator (D), thereby promoting the anionic addition reaction of the epoxy group and the thiol group contained in the sealant sheet to cure the sheet. That is, the technology disclosed herein includes a method including the following steps: a step of preparing a sealant sheet with a release liner having a photocurable sealant sheet and a light-transmitting release liner disposed on at least one surface of the sealant sheet; and a step of irradiating the sealant sheet with light across the light-transmitting release liner. Using such a method, the sealant sheet can be cured efficiently with good handling properties.

[0212] Light irradiation can be performed using a known appropriate light source such as a chemical lamp, a black light lamp (for example, a black light lamp manufactured by Toshiba Lighting & Technology Corporation), a metal halide lamp, etc. In some embodiments, a light source having a spectral distribution in the region of 250nm to 450nm in wavelength can be preferably used. By making the sealant sheet contain a sensitizer, the utilization efficiency of the light irradiated by the above-mentioned light source can be improved. For example, when using a light source having a spectral distribution in the region of 350nm to 450nm in wavelength, the use of a sensitizer is particularly effective.

[0213] The technology disclosed herein has a high degree of freedom in setting the curing speed of the sealant sheet after the curing treatment, for example, the curing speed can be intentionally delayed. Therefore, the curing speed after the curing treatment of the sealant sheet can be appropriately set, and light irradiation is performed at an appropriate time consistent with it to cure the sealant sheet. This means that the above-mentioned light irradiation is not limited to a specific time. For example, the anionic addition reaction of an epoxy group and a thiol group proceeds more slowly than general free radical polymerization, so the curing of the sealant sheet disclosed herein can be slowly performed. In the sealing method disclosed herein, since the sealant sheet that has been previously irradiated with light is arranged at the sealing object position, even if it is a sealant sheet used in a usage method that is difficult to uniformly irradiate sufficient light after the arrangement of the sealing object position (for example, a sealant sheet used in the sealing between opaque components, etc.), it can be well cured.

[0214] The tensile strength at break of the cured product formed by the sealant sheet disclosed herein or the cured product of the sealant as described above measured by the method described in the embodiments described later is preferably 0.7 MPa or more, preferably 0.9 MPa or more, more preferably more than 1.0 MPa, and may be 1.1 MPa or more or 1.15 MPa or more. In some embodiments, the tensile strength at break may be 1.2 MPa or more, or 1.3 MPa or more. There is no particular limit on the upper limit of the tensile strength at break, and from the perspective of being easy to take into account with other physical properties, for example, it may be 3 MPa or less.

[0215] In addition, the elongation at break of the cured product formed by the sealant sheet disclosed herein or the cured product of the sealant as measured by the following method is suitably 100% or more, preferably 120% or more, and may be 150% or more, 200% or more, or 250% or more. The upper limit of the elongation at break is not particularly limited, and from the viewpoint of being easy to take into account other physical properties, it may be, for example, 600% or less, or 400% or less.

[0216] (Determination of elongation at break)

[0217] A black light lamp manufactured by Toshiba Lighting & Technology Corporation was used to irradiate one side of the sealant sheet at 2000 mJ / cm 2 After the irradiated sealant sheet was kept at 25°C for 14 days, the obtained cured product (sealant cured product) was cut into a rectangular shape with a width of 10 mm and a length of 50 mm to prepare a sample sheet. The sample sheet prepared in this way was clamped in the chuck of the tensile tester in such a way that the distance between the chucks became 20 mm, and stretched at a speed of 50 mm / min according to JIS K6767. The elongation at break was calculated by the following formula based on the distance between the chucks L1 when the sample broke and the distance between the chucks L0 when the stretching started.

[0218] Elongation at break (%) = ((L1-L0) / L0) × 100

[0219] Matters disclosed in this specification include the following matters.

[0220] [1] A sealing method, comprising:

[0221] A step of preparing a photocurable sealant sheet;

[0222] a step of subjecting the sealant sheet to light irradiation treatment; and

[0223] A step of attaching the sealant sheet to an object to be sealed.

[0224] [2] The method according to [1] above, wherein a delayed curing photocurable sealant sheet is used as the sealant sheet.

[0225] [3] The method according to [1] or [2] above, wherein a photoanion-curable sealant sheet is used as the sealant sheet.

[0226] [4] The method according to any one of [1] to [3] above, wherein the attaching step is performed before the 25° C. storage modulus of the sealant sheet exceeds 0.7 MPa.

[0227] [5] The method according to any one of [1] to [4] above, wherein a photocurable sealant sheet is used as the sealant sheet, and the exposed surface of the sealant sheet is subjected to a black light lamp at 2000 mJ / cm 2 The storage modulus at 25° C. after irradiation with light for 1 hour was 0.7 MPa or less.

[0228] [6] The method according to any one of [1] to [5] above, wherein the sealant sheet is a photocurable sealant sheet that forms a sealant cured product having a tensile breaking strength of 0.7 MPa or more.

[0229] [7] The method according to any one of [1] to [6] above, wherein the sealant sheet is a photocurable sealant sheet having a storage elastic modulus of 0.005 MPa to 0.6 MPa at 25° C. before the light irradiation treatment.

[0230] [8] The method according to any one of [1] to [7] above, wherein the sealant sheet is a photocurable sealant sheet made of a polysulfide-based sealant.

[0231] [9] The method according to any one of [1] to [8] above, wherein a photocurable sealant sheet containing a photobase generator is used as the sealant sheet.

[0232]

[10] A photocurable sealant sheet for use in carrying out the method described in any one of [1] to [9] above.

[0233]

[11] The sealant sheet according to

[10] above, wherein the sealant sheet comprises the following components:

[0234] An epoxy-containing polysulfide polymer (AB) having two or more epoxy groups in one molecule;

[0235] a thiol compound (C) having two or more thiol groups in one molecule; and

[0236] Photobase generator (D).

[0237]

[12] The sealant sheet according to

[11] above, wherein the epoxy-containing polysulfide polymer (AB) is a polysulfide polymer containing epoxy groups at both ends.

[0238]

[13] The sealant sheet according to

[11] or

[12] , wherein the thiol compound (C) has a thiol equivalent of 45 g / eq or more and 450 g / eq or less.

[0239]

[14] The sealant sheet according to

[11] above, wherein the epoxy-containing polysulfide polymer (AB) is a reaction product of a thiol polysulfide having a Mw of 500 to 10,000 at both ends and having a disulfide structure in the main chain and an epoxy compound having two or more epoxy groups in one molecule.

[0240]

[15] The sealant sheet according to

[14] above, wherein the epoxy compound includes a bifunctional epoxy compound.

[0241]

[16] The sealant sheet according to

[15] above, wherein the bifunctional epoxy compound includes an epoxy compound having a carbon ring structure having five or more members in its molecule.

[0242]

[17] The sealant sheet according to any one of

[14] to

[16] above, wherein the epoxy compound includes a trifunctional or higher-functional epoxy compound.

[0243]

[18] The sealant sheet according to

[17] above, wherein the polyfunctional epoxy compound includes a novolac-type epoxy resin.

[0244]

[19] The sealant sheet with a release liner according to

[10] above, wherein the sealant sheet comprises the following components:

[0245] A thiol group-containing polysulfide polymer (AC) having two or more thiol groups in one molecule;

[0246] An epoxy compound (B) having two or more epoxy groups in one molecule; and

[0247] Photobase generator (D).

[0248]

[20] The sealant sheet according to

[19] above, wherein the thiol group-containing polysulfide polymer (AC) is a polysulfide polymer having thiol groups at both ends.

[0249]

[21] The sealant sheet according to

[19] or

[20] , wherein the epoxy compound (B) has an epoxy equivalent of 50 g / eq or more and 600 g / eq or less.

[0250]

[22] The sealant sheet according to any one of

[11] to

[21] , wherein the photobase generator (D) comprises an ionic photobase generator having a biguanide-type cation.

[0251]

[23] The sealant sheet according to any one of

[11] to

[22] above, further comprising a sensitizer.

[0252]

[24] The sealant sheet according to any one of

[11] to

[23] above, further comprising a filler.

[0253]

[25] The sealant sheet according to

[24] above, wherein the content of the filler is 1% by weight or more and less than 40% by weight of the entire sealant sheet.

[0254]

[26] The sealant sheet according to

[14] or

[25] , wherein the average particle size of the filler is 0.1 μm or more and 30 μm or less.

[0255]

[27] The sealant sheet according to any one of

[10] to

[26] above, wherein the thickness is 0.01 mm to 10 mm.

[0256]

[28] A sealant sheet with a release liner, comprising: the sealant sheet according to any one of

[10] to

[27] above; and a release liner having a release surface in contact with at least one surface of the sealant sheet.

[0257] Example

[0258] Hereinafter, some examples related to the present invention will be described, but the present invention is not intended to be limited to the contents shown in the examples. It should be noted that "parts" in the following description are based on weight unless otherwise specified.

[0259] <Production Example 1>

[0260] Using a reaction vessel equipped with a stirrer, 90 parts of a liquid polysulfide polymer (a polysulfide polymer containing thiol at both ends), 6.7 parts of a bifunctional epoxy compound, 2 parts of a polyfunctional epoxy compound, and 0.01 parts of a basic catalyst were heated at 90° C. for 3 hours while stirring. Then, the contents of the reaction vessel were transferred to another vessel and kept at 50° C. for 168 hours. In this way, a polysulfide polymer containing epoxy at both ends was synthesized.

[0261] After taking out the contents of the other container and cooling to room temperature, 1 part of a secondary bifunctional thiol compound, 1 part of a photobase generator, 0.5 parts of a storage stabilizer, and 30 parts of talc as a filler were added and uniformly kneaded using a two-roll mill. The obtained mixture was formed into a sheet using a vacuum press to obtain the sealant sheet of this example. At this time, two types of sheets were prepared: a sheet with a thickness of 0.2 mm and a sheet with a thickness of 1 mm.

[0262] It should be noted that as the liquid polysulfide polymer, the product name "THIOKOL LP-55" (manufactured by TORAYFINE CHEMICALS CO., LTD., polysulfide with thiol at both ends, weight average molecular weight 4000) was used, as the bifunctional epoxy compound, the product name "jER806" (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin, epoxy equivalent 177 g / eq) was used, as the multifunctional epoxy compound, the product name "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol novolac type epoxy resin, epoxy equivalent 176 to 178 g / eq) was used, as the basic catalyst, 2,4,6-triaminomethylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used, and as the secondary bifunctional thiol compound, the product name "Karenz MTBD1" (manufactured by Showa Denko K.K., 1,4-bis(3-mercaptobutyryloxy)butane, thiol equivalent 147.2 g / eq), as the photobase generator, the product name "WPBG-266" (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., a biguanide photobase generator) was used, as the storage stabilizer, the product name "CUREDUCT L-07N" (manufactured by Shikoku Chemicals Co., Ltd., a borate compound) was used, and as the filler (talc), the product name "MICRO ACE SG-95" (manufactured by NIPPON TALC Co., Ltd., talc powder, average particle size 2.5 μm) was used.

[0263] A sealant sheet with a thickness of 0.2 mm was sandwiched between two release liners to prepare a sealant sheet with release liners disposed on each side of the sealant sheet. Specifically, as the release liner disposed on the light irradiation side described later, a release liner R1 (manufactured by NIPPA Co., Ltd.) having a single side of a PET film as a release surface, a light transmittance of 64.2% at a wavelength of 365 nm, and a thickness of 50 μm was used. As another release liner, a polyester release liner manufactured by Mitsubishi Chemical Corporation was used.

[0264] (Determination of initial storage modulus)

[0265] The storage modulus (initial storage modulus) of the obtained sealant sheet before the light irradiation treatment was measured by the following method. As a result, the initial storage modulus of the sealant sheet was in the range of 0.02 MPa to 0.2 MPa.

[0266] [Measurement method]

[0267] A sealant sheet with a thickness of 1 mm was punched into a disk with a diameter of 8 mm, and held between parallel plates. The storage modulus G' was measured using a viscoelasticity tester (TA Instruments Japan Inc., model "ARESG2") at a measurement temperature of 25° C., a frequency of 1 Hz, and a strain of 0.5%.

[0268] (Measurement of storage modulus 1 hour after light irradiation)

[0269] The storage elastic modulus of the obtained sealant sheet 1 hour after light irradiation was measured by the following method. As a result, the storage elastic modulus of the sealant sheet 1 hour after light irradiation was higher than the initial storage elastic modulus and was 0.5 MPa or less.

[0270] [Measurement method]

[0271] In an environment of 25°C, a black light lamp manufactured by Toshiba Lighting & Technology Corporation was used to directly conduct irradiation of 2000 mJ / cm from one side of a 1 mm thick sealant sheet. 2 The sealant sheet after light irradiation was left to stand at 25° C. for 1 hour, and then the storage modulus G′ was measured in the same manner as the measurement of the initial storage modulus.

[0272] (Tensile breaking strength of cured sealant)

[0273] The release liner R1 on the light irradiation side was peeled off from the obtained sealant sheet with release liner to expose the surface of the sealant sheet (thickness 0.2 mm), and the exposed surface was irradiated with 2000 mJ / cm2 of black light lamp manufactured by Toshiba Lighting & Technology Corporation. 2 of light exposure.

[0274] After the irradiated sealant sheet was kept at 25°C for 14 days, the obtained cured product (sealant cured product) was cut into a rectangular shape with a width of 10 mm and a length of 50 mm to prepare a sample sheet. The sample sheet was clamped in the chuck of a tensile tester so that the distance between the chucks was 20 mm, and stretched at a speed of 50 mm / min according to JIS K6767. The maximum strength observed until the sample sheet broke was taken as the breaking strength. As a result, the tensile breaking strength of the sealant cured product was about 1.5 MPa.

[0275] <Production Example 2>

[0276] As the light irradiation release liner disposed on the light irradiation side described later, a release liner R2 (manufactured by Mitsubishi Chemical Corporation, thickness 38 μm, light transmittance at wavelength 365 nm 91%) having a polyester film with a release surface having a silicone-based release treatment agent on one side was used. Other operations were performed in the same manner as in Manufacturing Example 1 to prepare a sealant sheet with a release liner of this Manufacturing Example.

[0277] <Production Example 3>

[0278] As a release liner disposed on the light irradiation side described below, a release liner R3 (manufactured by NIPPA Co., Ltd.) having a light transmittance of 0.5% at a wavelength of 365 nm was used. Otherwise, the same operation as in Production Example 1 was performed to prepare a sealant sheet with a release liner of this Production Example.

[0279] The light transmittance (wavelength 365 nm) of the release liner was measured using a UV-vis spectrometer (manufactured by Shimadzu Corporation, product name "UV-2550"), and the value at a wavelength of 365 nm was taken as the light transmittance (wavelength 365 nm) of the release liner.

[0280] <Experimental Example 1>

[0281] The sealant sheet with a release liner prepared in Production Example 1 was irradiated with 2000 mJ / cm2 of release liner R1 (release liner on the light irradiation side) using a black light lamp manufactured by Toshiba Lighting & Technology Corporation. 2 After irradiation with light for 1 hour, the release liner on the light irradiation side was peeled off from the sealant sheet with a release liner, and the exposed sealant sheet surface was attached to a stainless steel plate (SUS304BA plate). Next, the other release liner was peeled off from the sealant sheet and kept in an environment of 25°C for 14 days. Thus, a sealant cured product with no stickiness on the surface and sufficient hardness to leave no marks even when pressed with a thumb was formed.

[0282] <Experimental Example 2>

[0283] The sealant sheet with a release liner prepared in Production Example 2 was irradiated with 2000 mJ / cm2 of release liner R2 (release liner on the light irradiation side) using a black light lamp manufactured by Toshiba Lighting & Technology Corporation. 2 After irradiation with light for 1 hour, the release liner on the light irradiation side was peeled off from the sealant sheet with a release liner, and the exposed sealant sheet surface was attached to a stainless steel plate (SUS304BA plate). Next, the other release liner was peeled off from the sealant sheet and kept in an environment of 25°C for 14 days. Thus, a sealant cured product with no stickiness on the surface and sufficient hardness to leave no marks even when pressed with a thumb was formed.

[0284] <Experimental Example 3>

[0285] The release liner R3 on the light-irradiated side was peeled off from the sealant sheet with a release liner prepared in Production Example 3, and the exposed sealant sheet surface was subjected to a 2000 mJ / cm2 black light lamp manufactured by Toshiba Lighting & Technology Corporation. 2 After irradiation with light for 1 hour, the exposed surface of the sealant sheet was attached to a stainless steel plate (SUS304BA plate). Next, the other release liner was peeled off from the sealant sheet and kept in an environment of 25°C for 14 days. Thus, a sealant cured product with no stickiness on the surface and sufficient hardness to leave no marks even when pressed with a thumb was formed.

[0286] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The aspects described in the scope of the claims include various modifications and changes to the specific examples described above.

[0287] Description of Reference Numerals

[0288] 10 Sealing object

[0289] 12, 14, 16 components

[0290] 21 Sealant sheet

[0291] 21A A surface

[0292] 21B Another Surface

[0293] 31, 32 Release liner

[0294] 100, 200 Sealant sheet with release liner

Claims

1. A sealing method, comprising: A step of preparing a light-curing sealant sheet; a step of subjecting the sealant sheet to a light irradiation treatment; and a step of attaching the sealant sheet to a sealed object, The attaching step is performed before the 25°C storage modulus of the sealant sheet exceeds 0.7 MPa, As the sealant sheet, a photoanion curable sealant sheet is used. The sealant sheet comprises: an epoxy-containing polysulfide polymer (AB) having two or more epoxy groups in one molecule, a thiol compound (C) having two or more thiol groups in one molecule, and a photobase generator (D); Alternatively, the sealant sheet includes a thiol group-containing polysulfide polymer (AC) having two or more thiol groups in one molecule, an epoxy compound (B) having two or more epoxy groups in one molecule, and a photobase generator (D).

2. The method according to claim 1, wherein: As the sealant sheet, a delayed curing type photocurable sealant sheet is used.

3. The method according to claim 1 or 2, wherein: As the sealant sheet, a photocurable sealant sheet was used. The exposed surface of the sealant sheet was subjected to a 2000 mJ / cm 2 The storage modulus at 25° C. after irradiation with light for 1 hour was 0.7 MPa or less.

4. The method according to claim 1 or 2, wherein: As the sealant sheet, a photocurable sealant sheet that forms a sealant cured product having a tensile breaking strength of 0.7 MPa or more is used.

5. The method according to claim 1 or 2, wherein: As the sealant sheet, a photocurable sealant sheet having a storage elastic modulus of 0.005 MPa or more and 0.6 MPa or less at 25° C. before the light irradiation treatment is used.

6. The method according to claim 1 or 2, wherein: As the sealant sheet, a photocurable sealant sheet formed of a polysulfide-based sealant is used.

7. The method according to claim 1 or 2, wherein: As the sealant sheet, a photocurable sealant sheet containing a photobase generator is used.

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