Resin composition and method for forming coating layer on plate-like object

Abstract

To provide a resin composition capable of suppressing stress generated internally when forming a coating layer on a plate and maintaining high productivity and a forming method for the coating layer on a plate using the resin composition.SOLUTION: The resin composition is composed by including a photopolymerization initiator in a composition including (meth)acrylate, a plasticizer or reactive diluent, and an adhesive agent. By mixing these multiple materials in appropriate portions, it is possible to achieve a resin composition that can be cured in a short time while suppressing shrinkage. It is possible to prevent so-called springback, which is caused by the reappearance of warpage or undulation when a coating layer formed on a plate-like object is removed.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a resin composition used for forming a coating layer on a plate-like object such as a wafer, and a method for forming a coating layer on a plate-like object using the resin composition. [Background technology]

[0002] Wafers, which are the material for semiconductor devices (devices), are usually cut from ingots made of semiconductors such as silicon, silicon carbide, and gallium nitride using tools such as band saws and wire saws.

[0003] The wafers immediately after being sliced ​​in this way (as-sliced ​​wafers) have warping and waviness. Therefore, a processing method has been proposed in which a resin is applied to one side of the wafer and cured to form a coating layer, a reference surface is formed with this coating layer, and then the reference surface side is held on a table while the grinding surface exposed on the other side is ground, thereby removing the warping and waviness and flattening the wafer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-148866 A Summary of the Invention [Problem to be solved by the invention]

[0005] In general, resins containing liquids such as water or solvents shrink when the liquid evaporates. In addition, curable resins that are cured by light or heat tend to shrink due to changes in volume before and after curing. If a resin with a high shrinkage rate during curing is used to form a coating layer on a plate-like object such as a wafer, stress will be generated inside the plate-like object due to the shrinkage of the resin.

[0006] If a plate-shaped object is ground flat while internal stress is generated, the internal stress is released when the resin is removed, causing the warping and undulations to reappear (the phenomenon known as springback). This problem can be solved by using a resin with a sufficiently low shrinkage rate when hardened to reduce the force applied to the plate-shaped object.

[0007] However, resins with low shrinkage are difficult to cure and are not suitable for forming a coating layer on a plate-shaped object, and since it takes a long time to complete curing, productivity is also low.

[0008] Therefore, there is currently a demand for a resin composition that can be cured easily in a short time while suppressing the shrinkage rate during curing to a low level.

[0009] The present invention has been made in consideration of the above, and aims to provide a resin composition that can reduce internal stress when forming a coating layer on a plate-like object and maintain high productivity, and a method for forming a coating layer on a plate-like object using the resin composition. [Means for solving the problem]

[0010] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0011] According to one aspect of the present invention, a resin composition for fixing a plate-like object is provided, characterized in that a photopolymerization initiator is added to a composition consisting of a (meth)acrylate, a plasticizer or a reactive diluent, and a tackifier.

[0012] According to one embodiment of the present invention, the resin composition contains 25% by mass or more and 55% by mass or less of the (meth)acrylate, 35% by mass or more and 65% by mass or less of the plasticizer or reactive diluent, and 0.1% by mass or more and 10% by mass or less of the tackifier.

[0013] According to one embodiment of the present invention, the (meth)acrylate is either a (meth)acrylate having a urethane bond or a (meth)acrylate not having a urethane bond, or a mixture thereof.

[0014] According to one aspect of the present invention, there is provided a method for forming a coating layer on a plate-shaped object using a resin composition, the method comprising: a resin composition supplying step of supplying the resin composition onto a film; On the m the resin composition is applied to the first surface of the plate-like object by a contacting step, the film is placed on a stage together with the plate-like object, a pressing step is performed by applying a force from the second surface side of the plate-like object toward the first surface, thereby pressing the plate-like object toward the stage and spreading the resin composition over the entire first surface, and a curing step is performed by irradiating the resin composition covering the first surface of the plate-like object with light to cure the resin composition.

[0015] According to one embodiment of the present invention, the film contains a (meth)acrylate. Effect of the Invention

[0016] According to one aspect of the present invention, a resin composition can be realized that can be cured in a short time while suppressing shrinkage, and so-called springback, which is the phenomenon in which warping or swells reappear when a coating layer formed on a plate-shaped object is removed, can be prevented.

[0017] Moreover, according to one embodiment of the present invention, the inclusion of (meth)acrylate in the film makes it possible to more firmly fix the coating layer and the film, making it easier to peel off the coating layer together with the film in a later process, and preventing the coating layer from remaining on the plate-like object. [Brief description of the drawings]

[0018] [Figure 1] 1A is a perspective view showing an example of a plate-like article on which a coating layer is formed using the resin composition of the present embodiment, and FIG. 1B is a cross-sectional view showing the example of the plate-like article. [Diagram 2] FIG. 2 is a perspective view showing a schematic configuration example of a coating layer forming device for forming a coating layer on a plate-like object. [Diagram 3] 1 is a flowchart of a method for forming a coating layer according to one embodiment of the present invention. [Figure 4] 1A is a partially sectional side view that illustrates a method for forming a coating layer on a plate-like object using a resin composition, and FIG. 1B is a view illustrating a pressing step. [Diagram 5] FIG. 1A is a diagram illustrating the curing step, and FIG. 1B is a diagram showing the state after the curing step has been completed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An embodiment of the present invention will be described with reference to the accompanying drawings. The resin composition according to the present embodiment is used to form a coating layer on a plate-like object such as a wafer. Fig. 1(A) is a perspective view showing an example of a plate-like object on which a coating layer is formed with the resin composition of the present embodiment, and Fig. 1(B) is a cross-sectional view showing an example of the plate-like object.

[0020] As shown in Fig. 1(A), the plate-like object 11 is a disk-like wafer (as-sliced ​​wafer) cut by a tool such as a band saw or a wire saw from a cylindrical ingot made of a semiconductor such as silicon, silicon carbide, gallium nitride, etc. As shown in Fig. 1(B), this plate-like object 11 has warping and undulations due to being cut from the ingot.

[0021] A warped or wavy plate-like object 11 is not suitable for forming a device or the like. Therefore, it is necessary to form a coating layer of a resin composition on the plate-like object 11 and flatten it. For example, the resin composition applied to the back surface (first surface) 11b of the plate-like object 11 is cured to form a flat reference surface, and then the front surface (second surface) 11a of the plate-like object 11 is ground to remove the warp and wavy of the plate-like object 11.

[0022] Fig. 2 is a perspective view showing a schematic configuration example of a coating layer forming apparatus for forming a coating layer on a plate-like object 11. As shown in Fig. 2, the coating layer forming apparatus 2 includes a feed roller 4 on which a film 13 wound in a roll shape is attached, and a take-up roller 6 that takes up the film 13 fed from the feed roller 4.

[0023] The feed roller 4 and the take-up roller 6 are each connected to a rotation drive source (not shown) such as a motor, and move the film 13 from the feed roller 4 side to the take-up roller 6 side. The film 13 is formed of a resin material such as (meth)acrylate (acrylic resin).

[0024] A resin supplying unit 8 such as a slit coater is disposed above the delivery roller 4. This resin supplying unit 8 supplies a resin composition 15 according to one embodiment of the present invention (see FIGS. 4 and 5) to the front surface 13a side of the film 13 delivered from the delivery roller 4.

[0025] A pair of upper and lower rollers 10, 12 are provided above the resin supply unit 8 to position the plate-like object 11 on the surface 13a of the film 13 to which the resin composition 15 has been supplied. The lower roller 10 changes the traveling direction of the film 13 to position the surface 13a to which the resin composition 15 has been supplied upward.

[0026] A plate-like object 11 is placed on the front surface 13a of the film 13 via the resin composition 15. In this embodiment, the back surface 11b side of the plate-like object 11 is brought into contact with the resin composition 15. However, the front surface 11a side of the plate-like object 11 may also be brought into contact with the resin composition 15. Thereafter, the upper roller 12 rotates in contact with the plate-like object 11 placed on the film 13. The plate-like object 11 is sandwiched together with the film 13 between the rollers 10 and 12 and positioned at a predetermined position.

[0027] The plate-like object 11 positioned at a predetermined position by the rollers 10 and 12 is transported together with the film 13 to the adjacent resin curing unit 14. The resin curing unit 14 includes a substantially rectangular parallelepiped base 16 having an internal space. A stage 18 having a substantially flat upper surface is disposed on the upper portion of the base 16 so as to close the internal space.

[0028] Stage 18 is made of, for example, borate glass, quartz glass, or the like, and transmits light with a wavelength that hardens resin composition 15. The upper surface of stage 18 serves as a holding surface that holds film 13 transported from the rollers 10 and 12 side. Film 13 placed on stage 18 is suctioned and held on the holding surface by a suction mechanism (not shown) or the like.

[0029] A light source 20 is disposed below the stage 18, which emits light of a wavelength that cures the resin composition 15. A shutter 22 that blocks light from the light source 20 is provided between the stage 18 and the light source 20. In addition, a filter 24 that blocks light of a wavelength that is not necessary for curing the resin composition 15 is disposed above the shutter 22.

[0030] When the shutter 22 is completely closed, the light from the light source 20 is blocked by the shutter 22 and does not reach the stage 18. On the other hand, when the shutter 22 is open, the light from the light source 20 passes through the filter 24 and the stage 18 and is irradiated onto the film 13. The film 13 is configured to be able to transmit light of a wavelength that cures the resin composition 15, and the resin composition 15 is cured by the light that has passed through the film 13.

[0031] An exhaust pipe 26 that connects to the internal space is provided on the side wall of the base 16. This exhaust pipe 26 is connected to an exhaust pump (not shown) or the like outside the base 16. If the temperature inside the base 16 rises due to the light from the light source 20, the stage 18 will deform and the flatness of the holding surface will decrease. For this reason, the inside of the base 16 is evacuated by an exhaust pump or the like connected to the exhaust pipe 26 to suppress the temperature rise.

[0032] A support structure 28 is provided at a position adjacent to the stage 18. The support structure 28 includes a wall portion 28a erected on the base 16, and an overhanging portion 28b extending horizontally from the upper end of the wall portion 28a. A pressing mechanism 30 that presses the plate-like object 11 on the film 13 downward is provided at the center of the overhanging portion 28b located above the stage 18.

[0033] The pressing mechanism 30 includes a central main rod 32 extending in the vertical direction, and multiple (four in this embodiment) secondary rods 34 arranged parallel to the main rod 32. The multiple secondary rods 34 are arranged at approximately equal intervals around the main rod 32. A disk-shaped pressing pad 36 corresponding to the shape of the plate-like object 11 is fixed to the lower ends of the main rod 32 and the multiple secondary rods 34.

[0034] The main rod 32 and the multiple secondary rods 34 are each connected to a lifting mechanism (not shown) including a motor, etc. By lowering the main rod 32 and the multiple secondary rods 34 with this lifting mechanism, the front surface 11a side of the plate-like object 11 can be pressed by the pressure pad 36. The lifting mechanism independently raises and lowers the main rod 32 and the multiple secondary rods 34 to adjust the pressing force applied to the plate-like object 11.

[0035] After the back surface 11b side of the plate-like object 11 is placed on the resin composition 15 on the film 13, the front surface 11a side is pressed by the pressing mechanism 30 described above to uniformly spread the resin composition 15 between the front surface 13a of the film 13 and the back surface 11b of the plate-like object 11. Thereafter, the resin composition 15 is irradiated with light from the light source 20, whereby the resin composition 15 is cured and a coating layer can be formed on the plate-like object 11.

[0036] It is preferable that the film 13 contains (meth)acrylate. By containing (meth)acrylate in the film 13, the coating layer and the film are more firmly fixed, the coating layer can be easily peeled off together with the film in a later step, and the coating layer can be prevented from remaining on the plate-like object.

[0037] The plate-like object 11 having the coating layer formed of the resin composition 15 is transported to the adjacent film cutting unit 38. The film cutting unit 38 includes a substantially rectangular parallelepiped base 40. A table 42 having a substantially flat upper surface is disposed on the upper portion of the base 40. The upper surface of this table 42 serves as a holding surface for holding the film 13 transported from the resin curing unit 14 side.

[0038] A support structure 44 is provided adjacent to the table 42. The support structure 44 includes a wall portion 44a erected on the base 40 and an overhanging portion 44b extending horizontally from the upper end of the wall portion 44a. A cutting mechanism 46 that cuts the film 13 into a circular shape is provided in the center of the overhanging portion 44b located above the table 42.

[0039] Cutting mechanism 46 includes rod 48 extending vertically and cutter 50 equipped with a ring-shaped blade with a diameter larger than that of plate-like object 11. Cutter 50 is fixed to the lower end of rod 48, and moves up and down by an elevating mechanism (not shown) such as an air cylinder connected to the upper part of rod 48. When cutter 50 is lowered by this elevating mechanism and brought into contact with film 13 on table 42, film 13 can be cut into a circle corresponding to the outer shape of plate-like object 11.

[0040] The plate-like object 11 on which the coating layer has been formed by the coating layer forming device 2 has its surface 11a side ground by, for example, a grinding device (not shown), and then the resin composition 15 and the film 13 are removed.

[0041] The resin composition 15 according to one embodiment of the present invention is cured in a short time while suppressing shrinkage, so that it is possible to keep the internal stress generated when a coating layer is formed on the plate-like object 11 low and maintain high productivity.

[0042] Resin composition 15 is obtained by adding a photopolymerization initiator to composition A, which is made of (meth)acrylate, a plasticizer or reactive diluent, and a tackifier. By mixing such a plurality of materials in appropriate amounts, a resin composition that can be cured in a short time while suppressing shrinkage can be realized, and so-called springback, which is caused by warping or swell reappearing when a coating layer formed on a plate-like object is removed, can be prevented.

[0043] The resin composition 15 contains the following three components at predetermined mass %. Component 1: (meth)acrylate, 25% by mass or more and 55% by mass or less Component 2: Plasticizer or reactive diluent 35% to 65% by mass Component 3: Tackifier: 0.1% by mass to 10% by mass

[0044] The composition containing the above components 1, 2, and 3 is referred to as Composition A in this specification.

[0045] The (meth)acrylate is defined as being composed of either a (meth)acrylate having a urethane bond or a (meth)acrylate not having a urethane bond, or a mixture thereof.

[0046] In the composition A, as the content of the (meth)acrylate having a urethane bond increases, the curability increases and the shrinkage rate during curing decreases.

[0047] In the composition A, as the content of the (meth)acrylate not having a urethane bond increases, the curability increases and the shrinkage rate during curing increases.

[0048] In the composition A, a (meth)acrylate having a urethane bond and a (meth)acrylate having no urethane bond can be mixed and contained. Here, the (meth)acrylate having a urethane bond has a tendency to have a large molecular weight and high viscosity due to the presence of a urethane bond in the molecule. On the other hand, the (meth)acrylate having no urethane bond has a high shrinkage rate when cured, but has a lower viscosity and a higher hardness than the (meth)acrylate having a urethane bond. Therefore, by mixing and containing two types of (meth)acrylates with and without urethane bonds, it is possible to adjust the curability, shrinkage rate, and hardness.

[0049] Incidentally, the (meth)acrylate refers to an acrylate which is an acrylic acid compound, or a methacrylate which is a methacrylic acid compound, and a (meth)acrylate having a urethane bond (urethane group) refers to one having a urethane group in the molecule.

[0050] Specific examples of (meth)acrylates having a urethane bond include Light Acrylate IAA, AT-600, UA-306H, UA-306T, UA-306I, UA-510H, UF-8001G, DAUA-167, UF-07DF (all manufactured by Kyoeisha Chemical Co., Ltd.), R-1235, R-1220, RST-201, RST-402, R-1301, R-1304, R-1214, and R- 1302XT, GX-8801A, R-1603, R-1150D, DOCR-102, DOCR-206 (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), UX-3204, UX-4101, UXT-6100, UX-6101, UX-7101, UX-8101, UX-0937, UXF-4001-M35, UXF-4002, DPHA-40H, UX-5000, UX-5102D- M20, UX-5103D, UX-5005, UX-3204, UX-4101, UX-6101, UX-7101, UX-8101, UX-0937, UXF-4001-M35, UXF-4002, UXT-6100, DPHA-40H, UX-5000, UX-5102D-M20, UX-5103, and UX-5005 (all manufactured by Nippon Kayaku Co., Ltd.) can be used.

[0051] The (meth)acrylate having no urethane bond refers to one having no (urethane group) in the molecule. Specific examples include tetrahydrofurfuryl acrylate, isobornyl acrylate, phenyl glycidyl ether acrylate, 1,9-nonanediol diacrylate, and the like. Specifically, tetrahydrofurfuryl acrylate or isobornyl acrylate can be used.

[0052] The plasticizer may be an ester, which exhibits a low shrinkage rate. The plasticizer is a material that can enter the gaps in the resin, inhibit the resin from being regularly oriented, and maintain the amorphous state even below the glass transition point. This plasticizer has a property of being less reactive with the acrylic group of the (meth)acrylate, so that when the (meth)acrylate and the plasticizer are mixed and polymerized, the shrinkage rate of the resin composition 15a can be suppressed. Specifically, the plasticizer can be dimethyl phthalate, which is a phthalate ester, ethyl phthalyl ethyl glycolate, bis[2-(2-butoxyethoxy)ethyl]adipate, which is an aliphatic dibasic acid ester, N-butylbenzenesulfonamide, which is a sulfonamide, or benzoic acid glycol ester.

[0053] The reactive diluent may be an ether having a single epoxy group. The reactive diluent exhibits a low shrinkage rate. The reactive diluent reduces the viscosity without impairing the properties of the (meth)acrylate. The reactive diluent includes glycidyl ether, and specifically, glycidyl 2-ethylhexyl glycidyl ether, p-sec-butylphenyl glycidyl ether (Epiol (registered trademark) SB (NOF Corporation)), p-tert-butylphenyl glycidyl ether, etc. can be used.

[0054] The tackifier is also called a tackifier, and examples of such a tackifier include terpene resins, rosin-based resins, petroleum-based resins, alkylphenol resins, and xylene resins. The purpose of including a tackifier in composition A is to eliminate poor curing caused by the inclusion of a plasticizer or reactive diluent. That is, a plasticizer or reactive diluent inhibits the reaction between (meth)acrylates, inhibits the bonding between (meth)acrylates, and causes poor curing. Therefore, by including a tackifier, the (meth)acrylates are allowed to adhere to each other under conditions in which the reaction is inhibited, thereby eliminating poor curing.

[0055] The photopolymerization initiator is an agent for initiating the photopolymerization (ultraviolet ray polymerization) of the composition A described above. In this embodiment, 1-hydroxycyclohexyl phenyl ketone (e.g., Irgacure (registered trademark) 184 manufactured by BASF, etc.) and α-hydroxyalkylphenone (e.g., Omnirad (registered trademark) 184 manufactured by IGM Resins BV, etc.) are used as the photopolymerization initiator. The amount of the photopolymerization initiator is adjusted as desired within a range in which the curability of the resin composition 15 can be maintained.

[0056] The above-described apparatus configuration and the method for forming a coating layer on a plate-like object using the resin composition will be described below in the order of the flow chart shown in FIG.

[0057] <Resin composition supply step> In the production method according to the present embodiment, first, a resin composition supplying step is performed in which a resin composition 15 is supplied onto a film 13. Specifically, as shown in Fig. 2, a resin supplying unit 8 supplies the resin composition 15 onto a surface 13a side of the film 13 fed from a feed roller 4. The amount of the resin composition 15 supplied is set so that a coating layer formed by the resin composition 15 can be formed with a sufficient thickness to absorb warping and waviness of the plate-like object 11.

[0058] <Contact Step> Next, a contacting step is performed in which the first surface (rear surface 11b) of the plate-like object 11 is brought into contact with the resin composition 15 on the film 13. Specifically, as shown in Fig. 2, the film 13 and the plate-like object 11 placed on the film 13 are sandwiched between upper and lower rollers 10, 12, so that the plate-like object 11 is brought into contact with the resin composition 15.

[0059] <Placement step> Next, a placing step is performed in which the film 13 is placed on the stage 18 together with the plate-like object 11. Specifically, the film 13 is transported as shown in FIG. 2, whereby the plate-like object 11 is carried onto the stage 18 of the resin curing unit 14.

[0060] <Pressing step> Next, a pressing step is performed in which a force is applied from the second surface (front surface 11a) of the plate-like object 11 toward the first surface (back surface 11b) to press the plate-like object 11 toward the stage 18, and the resin composition 15 is spread over the entire first surface (back surface 11b). Specifically, first, as shown in Fig. 4(A), with the plate-like object 11 positioned below the pressing mechanism 30, the film 13 is sucked and held on the holding surface of the stage 18.

[0061] 4(B), the pressing pad 36 is lowered to a predetermined position and stopped there. As a result, the plate-like object 11 is pressed downward, and the resin composition 15 spreads uniformly over the entire first surface (rear surface 11b) of the plate-like object 11 between the front surface 13a of the film 13 and the first surface (rear surface 11b) of the plate-like object 11.

[0062] <Curing step> Next, a curing step is performed in which the resin composition 15 covering the first surface (rear surface 11b) of the plate-like object 11 is irradiated with light to cure the resin composition 15. Specifically, as shown in FIG. 5(A), a shutter 22 is opened while light 21 is being emitted from a light source 20, and the light 21 from the light source 20 is irradiated onto the resin composition 15. As a result, the resin composition 15 is cured, and a coating layer is formed on the plate-like object 11.

[0063] The upper surface of stage 18, which serves as the holding surface, is formed to be approximately flat, so that the lower surface of resin composition 15, which contacts surface 13a of film 13, is also approximately flat. In this embodiment, since the above-mentioned resin composition 15 is used, it is possible to form a coating layer on plate-like object 11 by hardening in a short time while suppressing shrinkage.

[0064] During the curing step, the change in the load acting on the pressure pad 36 is measured by a load measuring device (not shown). The load change starts when curing starts, and ends when curing is completed. By measuring the time from the start to the end of this load change, the measured time can be evaluated as the curing time.

[0065] After the curing is completed, as shown in FIG. 5(B), the shutter 22 is closed to stop the irradiation of light, and the pressure pad 36 is raised to release the plate-like object 11, and the plate-like object 11 with the resin layer formed on the underside is transported downstream.

[0066] The apparatus used to form the coating layer is not limited to the above-mentioned apparatus configuration. For example, a coating layer can be formed on the plate-like object 11 using a coating layer forming apparatus equipped with a holding mechanism for holding the plate-like object 11 above the stage. In this case, the plate-like object 11 is held by the holding mechanism so as to face the stage, and the resin composition 15 is supplied onto the stage, and then the plate-like object 11 is pressed against the stage to spread the resin composition 15 uniformly. Thereafter, the resin composition 15 is irradiated with light to form a coating layer on the plate-like object 11.

[0067] Next, an experiment conducted to confirm the effectiveness of the resin composition 15 according to this embodiment will be described.

[0068] <Experiment 1: No tackifier> In this experiment, the shrinkage rate and curing properties were evaluated in the absence of a tackifier. A coating layer was formed on a silicon wafer (as-sliced ​​wafer) using a plurality of resin compositions having different mixing ratios of (meth)acrylate and reactive diluent.

[0069] In this experiment, 0.2% by mass of a photopolymerization initiator was added based on the total amount of the (meth)acrylate and the reactive diluent. The (meth)acrylate used was UF-8001G (Kyoeisha Chemical Co., Ltd.) (having a urethane bond). The reactive diluent used was Epiol (registered trademark) SB (NOF Corporation). The photopolymerization initiator used was Omnirad (registered trademark) 184 (IGM Resins BV). The results of this experiment are as shown in the following table.

[0070] [Table 1]

[0071] The shrinkage rate (unit: %) was calculated by determining the volume A of the supplied resin composition before curing and the volume B of the resin composition after curing, and then using the following formula (1). Shrinkage rate = (A-B) / A x 100 (unit: %) In addition, curing time was rated as good (◯) when it was 10 seconds or less, as curing was fast, as opposed to 10 seconds to 15 seconds (△), and 16 seconds or more (×).

[0072] <Experiment 2: With tackifier> In this experiment, the shrinkage rate and curing properties were evaluated when a tackifier was contained. The (meth)acrylate used was UF-8001G (Kyoeisha Chemical Co., Ltd.) (having a urethane bond). The reactive diluent used was Epiol (registered trademark) SB (NOF Corporation). The tackifier used was YS Polystar UH115 (Yasuhara Chemical Co., Ltd.). The photopolymerization initiator used was Omnirad (registered trademark) 184 (IGM Resins BV).

[0073] [Table 2]

[0074] <Evaluation> As described above, in Experiment 2, it was confirmed that Samples 2-2 to 2-8 were able to achieve both low shrinkage and good curability.

[0075] <About shrinkage rate> As is clear from a comparison of Tables 1 and 2, it was confirmed that the inclusion of a tackifier reduces the shrinkage rate (%). For example, when comparing Sample 1-2 and Sample 2-1, both of which contain 60 mass% of the same (meth)acrylate, the shrinkage rate (%) is 2. 24 and 1.18. Low to This confirmed that the inclusion of a tackifier is effective in reducing the shrinkage rate (%).

[0076] Here, in Experiment 1 (Table 1), the reactive diluent was added for the purpose of lowering the shrinkage rate (%), but in Experiment 2 (Table 2), it was confirmed that the shrinkage rate (%) was further reduced by adding a tackifier in addition to the reactive diluent. Therefore, it can be said that the combination of a reactive diluent and a tackifier is effective in reducing the shrinkage rate (%).

[0077] <About hardening> As is clear from Table 2, it was confirmed that the inclusion of a tackifier resulted in good curability in Samples 2-2 to 2-8. This confirmed that the inclusion of a tackifier reduced the shrinkage rate (%) while also achieving good curability.

[0078] Regarding curability, there is concern that the inclusion of a reactive diluent may inhibit the reaction and bonding between (meth)acrylates, but it is believed that good curability can be obtained by adhering (meth)acrylates to each other using a tackifier. In addition, since the curability can be complemented by the tackifier, the content of the reactive diluent can be increased, and the function of the reactive diluent to shorten the curing time can be utilized. In other words, the curing time can be adjusted by setting the content of the tackifier and the reactive diluent.

[0079] In the above experiments 1 and 2, a (meth)acrylate having a urethane bond was used as the (meth)acrylate, but a similar reduction in shrinkage and good curability can be achieved when a (meth)acrylate without a urethane bond or a mixture of both is used. The effect of the tackifier is achieved whether or not a urethane bond is present, or whether both (meth)acrylates are used, and the type of (meth)acrylate to be used is appropriately selected depending on the desired curability, shrinkage, and hardness. In addition, a similar reduction in shrinkage and good curability can be achieved when a plasticizer is used instead of a reactive diluent. [Explanation of symbols]

[0080] 11 Plate-shaped objects 11a Front (2nd side) 11b Back side (first side) 13 Film 13a surface 15 Resin composition 2 Covering layer forming device 4 Delivery roller 6 Winding roller 8 Resin supply unit 10. Roller 12 Roller 14 Resin curing unit

Claims

1. A resin composition for fixing a plate-shaped object, (meth)acrylate, A plasticizer or reactive diluent; A tackifier; A photopolymerization initiator is added to the composition comprising the above. The resin composition comprises: The (meth)acrylate is present in an amount of 25% by mass or more and 55% by mass or less, The plasticizer or reactive diluent is 35% by mass or more and 65% by mass or less, The tackifier is contained in an amount of 0.1% by mass or more and 10% by mass or less. Resin composition.

2. A resin composition for fixing a plate-shaped object, comprising: (meth)acrylate, a plasticizer or reactive diluent; A tackifier; A photopolymerization initiator is added to the composition comprising the above. The resin composition comprises The (meth)acrylate is present in an amount of 25% by mass or more and 55% by mass or less, The plasticizer or reactive diluent is 35% by mass or more and 65% by mass or less, Contains 10% by mass of the tackifier; Resin composition.

3. The (meth)acrylate is either a (meth)acrylate having a urethane bond or a (meth)acrylate not having a urethane bond, or a mixture thereof. The resin composition according to claim 1 or 2.

4. A method for forming a coating layer on a plate-like object using the resin composition according to any one of claims 1 to 3, A resin composition supplying step of supplying the resin composition onto a film; a contacting step of contacting a first surface of a plate-shaped object with the resin composition on the film; a placing step of placing the film together with the plate-like object on a stage; a pressing step of applying a force from the second surface side of the plate-like object toward the first surface to press the plate-like object toward the stage, thereby spreading the resin composition over the entire first surface; a curing step of irradiating the resin composition covering the first surface of the plate-like object with light to cure the resin composition.

5. 5. The method for forming a coating layer on a plate-like object according to claim 4, wherein the film contains a (meth)acrylate.

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