Two-component curing coating and release sheet for mold release sheets

Abstract

The object of the present invention is to provide a two-component curable coating agent for release sheets capable of forming a release layer with excellent release properties and elongation. The two-component curable coating agent for release sheets of the present invention comprises a main agent containing a polyol (P) and a curing agent containing a polyisocyanate (I), wherein the polyol (P) comprises: a (meth)acrylic polyol (A) having a siloxane bond structural unit (S1) as shown in formula (1) having a content of more than 0% by mass and less than 12% by mass, and a (meth)acrylic polyol (B) having a siloxane bond structural unit (S1) as shown in formula (1) having a content of more than 12% by mass and less than 30% by mass.

Description

Technical Field

[0001] This invention relates to a two-component curable coating agent for release sheets and release sheets. Background Technology

[0002] Previously, semiconductor chips were sealed with sealing resin during the semiconductor sealing process to form a semiconductor package, which was then mounted on an electronic substrate. By creating a semiconductor package, the semiconductor chip can be protected from external impacts, heat, and humidity.

[0003] In semiconductor sealing processes, for example, a semiconductor package is obtained by curing a sealing resin within a mold in which a semiconductor chip is disposed. Thermosetting resins such as epoxy resins are typically used as sealing resins.

[0004] To improve the release properties of semiconductor packages relative to the mold, release tabs are pre-positioned on the inner surface of the mold during the semiconductor sealing process. After the release tabs are placed on the mold, they are sealed to the inner surface of the mold by means of vacuuming or other methods, and then the semiconductor chip is sealed. By using release tabs, mold contamination caused by sealing resin can be prevented, and the semiconductor package can be easily removed from the mold.

[0005] Previously, release sheets used in semiconductor packages were single-layer sheets made of ETFE (ethylene-tetrafluoroethylene copolymer) to offer excellent heat resistance and release properties. However, ETFE is expensive, and the release sheet is discarded after each semiconductor sealing process. Therefore, a cheaper release sheet is needed.

[0006] Therefore, Patent Document 1 discloses a laminated release sheet having a support layer and a release layer integrally laminated to one side of the support layer. The support layer uses a synthetic resin such as polybutylene terephthalate (PBT), thereby imparting heat resistance to the release sheet. Furthermore, as the release layer, a cured film of a urethane acrylate coating agent (release agent) is used.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2014 / 203872 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] However, in conventional laminated release sheets, the release properties of the release layer are insufficient. Therefore, sometimes it is not easy to peel the semiconductor package from the release sheet after the semiconductor sealing process is completed.

[0012] On the other hand, when the goal is only to improve the release properties of the release layer, the elongation of the release layer may sometimes be reduced. Therefore, when the inner surface of the mold has a complex shape or a large difference in elevation, the release sheet may sometimes fail to conform adequately to the shape of the inner surface of the mold and break. If the release sheet breaks, the sealant resin will flow out from the broken part and contaminate the mold.

[0013] Therefore, for conventional release sheets, it is difficult to improve release properties while reducing the elongation of the release layer. Release sheets with a release layer that takes into account both release properties and elongation are needed.

[0014] Therefore, the object of the present invention is to provide a two-component curable coating agent for release sheets that can form a release layer with excellent release properties and elongation, and a release sheet having a release layer having a cured film as the aforementioned two-component curable coating agent for release sheets.

[0015] Methods for solving problems

[0016] The present invention solves the above problems by using a two-component curable coating agent for release sheets.

[0017] The release film uses a two-component curing coating agent containing: a base agent containing a polyol (P) and a curing agent containing a polyisocyanate (I).

[0018] The above polyol (P) includes:

[0019] The content of the structural unit (S1) with siloxane bonds shown in formula (1) below is more than 0% by mass and less than 12% by mass of (meth)acrylic acid polyol (A), and

[0020] The content of the structural unit (S1) with siloxane bond shown in the following formula (1) is 12% by mass or more and 30% by mass or less (meth)acrylic acid polyol (B).

[0021] [Chemical Formula 1]

[0022]

[0023] (In equation (1), R) 1 and R 2 Each can be represented independently as a hydrogen atom or a monovalent hydrocarbon group; * indicates a bonding site.

[0024] Furthermore, the present invention solves the above problems by using a release sheet, which has a support layer and a release layer, the release layer being integrally stacked on one side of the support layer and being a cured film of a two-component curable coating agent for the release sheet.

[0025] The effects of the invention

[0026] According to the present invention, a two-component curable coating agent for release sheets that can form a release layer with excellent release properties and elongation can be provided, as well as a release sheet having a release layer having a cured film as the aforementioned two-component curable coating agent for release sheets. Attached Figure Description

[0027] Figure 1 This is a diagram used to illustrate the contact angle in this invention.

[0028] Symbol Explanation

[0029] S PET film surface

[0030] W is a droplet of distilled water.

[0031] The tangent of a droplet of distilled water (L)

[0032] P is the endpoint of the interface between the distilled water droplet W and the PET film surface S. Detailed Implementation

[0033] [Two-component curing coating for release sheets]

[0034] The two-component curable coating agent for release sheets of the present invention comprises: a base agent containing a polyol (P) and a curing agent containing a polyisocyanate (I).

[0035] The above polyol (P) includes:

[0036] The content of the structural unit (S1) with siloxane bonds shown in formula (1) below is more than 0% by mass and less than 12% by mass of (meth)acrylic acid polyol (A), and

[0037] The content of the structural unit (S1) with siloxane bond shown in the following formula (1) is 12% by mass or more and 30% by mass or less (meth)acrylic acid polyol (B).

[0038] [Chemical Formula 2]

[0039]

[0040] (In equation (1), R) 1 and R 2 Each atom represents a hydrogen atom or a monovalent hydrocarbon group independently; * indicates a bonding site (single bond).

[0041] (Meth)acrylic polyol (A) and (meth)acrylic polyol (B) each contain siloxane bonds (≡Si-O-). Specifically, (meth)acrylic polyol (A) contains the structural unit (S1) with siloxane bonds shown in formula (1) above. In addition, (meth)acrylic polyol (B) also contains the structural unit (S1) with siloxane bonds shown in formula (1) above. It should be noted that sometimes "the structural unit (S1) with siloxane bonds shown in formula (1) above" is simply referred to as "structural unit (S1)".

[0042] It should be noted that the structural unit (S1) contained in (meth)acrylic polyol (A) may be the same as or different from the structural unit (S1) contained in (meth)acrylic polyol (B).

[0043] In the above equation (1), R 1 and R 2 Each can be an independent hydrogen atom or a monovalent hydrocarbon group. R 1 and R 2 They can be the same or different, but being the same is preferred. Examples of monovalent hydrocarbon groups include alkyl, cycloalkyl, and aryl groups. Among them, alkyl is preferred.

[0044] The alkyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 10, even more preferably 1 to 6, and even more preferably 1 to 3. Examples of alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl. Among these, methyl and ethyl are preferred, and methyl is more preferred.

[0045] The cycloalkyl group preferably has 3 to 10 carbon atoms, more preferably 5 to 10, and even more preferably 5 or 6. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0046] The aryl group preferably has 6 to 14 carbon atoms, more preferably 6 to 10, and even more preferably 6 to 8. Examples of aryl groups include phenyl, naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, and 3-isopropylphenyl.

[0047] In the two-component curable coating of the present invention, polyurethane is formed by reacting the polyol (P) contained in the main agent with the polyisocyanate (I) contained in the curing agent, thereby enabling the two-component curable coating to cure and form a release layer. Furthermore, in the present invention, by using a (meth)acrylic polyol containing siloxane bonds as the polyol (P) contained in the main agent, the release properties of the release layer can be improved. However, when only a (meth)acrylic polyol containing siloxane bonds is used, the elongation of the release layer sometimes decreases, making it difficult to balance elongation and release properties for the release layer.

[0048] Further research by the inventors revealed that by using (meth)acrylic acid polyols (A) and (B) with siloxane bond content set within a given range, both elongation and release properties can be achieved in the release layer. The mechanism by which this effect is obtained is not yet clear, but the following mechanisms may be considered.

[0049] The siloxane bonds contained in (meth)acrylic polyols have the characteristic of readily orienting towards the surface of the release layer. Therefore, in a two-component curable coating agent, by using (meth)acrylic polyols (A) and (B) with siloxane bond contents set to a given range as polyols (P) in the main agent, the (meth)acrylic polyol (B) with a high siloxane bond content can easily migrate towards the surface of the release layer formed using the two-component curable coating agent, thus moderately increasing the concentration of siloxane bonds on the surface of the release layer. This improves the release properties of the release layer. On the other hand, as (meth)acrylic polyol (B) migrates towards the surface of the release layer, the (meth)acrylic polyol (A) with a low siloxane bond content easily migrates into the interior of the release layer, resulting in a large amount of (meth)acrylic polyol (A) present inside the release layer, thereby reducing the decrease in the elongation of the release layer.

[0050] As described above, in the two-component curable coating agent of the present invention, by using (meth)acrylic polyol (A) and (B) as polyol (P) included in the main agent, a release layer that balances release properties and elongation can be provided. It should be noted that the above mechanism is based on the inventors' conjecture, and the present invention is not limited to the above mechanism.

[0051] [Main Agent]

[0052] The two-component curable coating agent of the present invention comprises a main agent containing a polyol (P). The polyol (P) contained in the main agent includes (meth)acrylic polyol (A) and (meth)acrylic polyol (B).

[0053] It should be noted that (meth)acrylic acid refers to acrylic acid or methacrylic acid. Additionally, (meth)acrylate refers to acrylate or methacrylate.

[0054] [(Meth)acrylic acid polyol (A)]

[0055] The (meth)acrylic polyol (A) contained in the main agent contains a structural unit (S1) with siloxane bonds as shown in formula (1) above.

[0056] The content of the siloxane bond-containing structural unit (S1) shown in formula (1) above in the (meth)acrylic polyol (A) is more than 0% by mass, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, more preferably 1% by mass or more, and more preferably 3% by mass or more. The content of the siloxane bond-containing structural unit (S1) shown in formula (1) above in the (meth)acrylic polyol (A) is less than 12% by mass, preferably 11% by mass or less, more preferably 10% by mass or less, and more preferably 8% by mass or less. By making the content of the structural unit (S1) more than 0% by mass, the compatibility of (meth)acrylic polyol (A) with (meth)acrylic polyol (B) can be improved, thereby reducing the reduction in the elongation of the release layer. By making the content of the structural unit (S1) less than 12% by mass, the content of the siloxane bond in the release layer can be within a suitable range, thereby reducing the reduction in the elongation of the release layer.

[0057] It should be noted that the content of the structural unit (S1) with siloxane bonds shown in formula (1) above in the (meth)acrylic acid polyol can be determined using a nuclear magnetic resonance device. 1 H-NMR was measured under the following conditions.

[0058] (Measurement conditions)

[0059] Measuring instrument: Bruker, trade name "Ascend™ 400"

[0060] Solvent: Deuterated chloroform

[0061] Sample concentration: 50 mg / mL

[0062] Observation frequency: 400MHz

[0063] Chemical shift reference: chloroform

[0064] Number of scans: 64

[0065] Measurement temperature: 25℃

[0066] (Meth)acrylic acid polyol (A) is a polymer of (meth)acrylic acid monomers having hydroxyl groups at the ends or side chains. (Meth)acrylic acid polyol (A) can be obtained by polymerizing (meth)acrylic acid monomers in the presence of a free radical polymerization initiator using conventional methods for manufacturing acrylic polymers.

[0067] (Meth)acrylic monomers containing siloxane bonds (a1)

[0068] Preferably, the (meth)acrylic polyol (A) comprises a (meth)acrylic monomer (a1) unit containing a siloxane bond. That is, the (meth)acrylic polyol (A) is preferably a polymer of a (meth)acrylic monomer containing a (meth)acrylic monomer (a1) containing a siloxane bond.

[0069] The siloxane-bonded (meth)acrylic monomer (a1) preferably comprises the siloxane-bonded structural unit (S1) shown in formula (1) above. It should be noted that the siloxane-bonded structural unit (S1) shown in formula (1) included in the siloxane-bonded (meth)acrylic monomer (a1) can be the same structural unit as the siloxane-bonded structural unit (S1) shown in formula (1) included in the (meth)acrylic polyol (A) above; therefore, detailed description is omitted here. By including the siloxane-bonded (meth)acrylic monomer (a1) with the siloxane-bonded structural unit (S1) shown in formula (1) above, the siloxane-bonded structural unit (S1) shown in formula (1) above can be introduced into the (meth)acrylic polyol (A).

[0070] As a siloxane bond-containing (meth)acrylic acid monomer (a1), any known monomer can be used without particular restriction, and the monomer shown in the following formula (2) is preferred.

[0071] [Chemical Formula 3]

[0072]

[0073] (In equation (2), R) 5 R is an alkyl group having 1 to 12 carbon atoms. 6 R is an alkylene group having 1 to 10 carbon atoms. 7 (This represents a hydrogen atom or a methyl group, where p represents an integer greater than 2.)

[0074] In equation (2), R 5 The alkyl group shown preferably has 1 to 12 carbon atoms, more preferably 1 to 5. As R 5 Examples of alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-heptyl. Methyl, ethyl, and n-butyl are preferred, with n-butyl being more preferred.

[0075] In equation (2), R 6 The alkylene group shown preferably has 1 to 10 carbon atoms, more preferably 1 to 5. As R 6 Examples of alkylene compounds include methylene, ethylene, n-propylene, and n-butylene. Among these, n-propylene (-CH2-CH2-CH2-) is preferred.

[0076] In formula (2), p is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In formula (2), p is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less.

[0077] Alternatively, monomers represented by the following formula (3) are also preferred as (meth)acrylic acid monomers containing siloxane bonds (a1).

[0078] [Chemical Formula 4]

[0079]

[0080] (In equation (3), R) 8 and R 11 They are hydrogen atoms or methyl groups, respectively, R 9 and R 10 These are alkylene groups with 1 to 10 carbon atoms, and q represents an integer greater than 2.

[0081] In equation (3), R 9 and R 10 The number of carbon atoms in each of the alkylene groups shown is preferably 1 to 10, more preferably 1 to 5. As R 9 and R 10 Examples of the alkylene groups shown include methylene, ethylene, n-propylene, and n-butylene. It should be noted that R... 9 and R 10 They can be the same or different.

[0082] In formula (3), q is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In formula (3), q is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less.

[0083] Specific examples of (meth)acrylic monomers (a1) containing siloxane bonds include α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane, α-mono(methacryloyloxymethyl)polydimethylsiloxane, and α,ω-di(methacryloyloxymethyl)polydimethylsiloxane.

[0084] The siloxane-bonded (meth)acrylic monomer (a1) preferably comprises at least one of the monomers shown in formula (2) and formula (3) above, and may also comprise both monomers. Among them, the siloxane-bonded (meth)acrylic monomer (a1) is preferably the monomer shown in formula (2) above, and more preferably α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane. The siloxane-bonded (meth)acrylic monomer (a1) can be used alone or in combination of two or more.

[0085] The number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (a1) is preferably 500 or more, more preferably 1000 or more, more preferably 5000 or more, and even more preferably 8500 or more. The number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (a1) is preferably 50000 or less, more preferably 25000 or less, and even more preferably 15000 or less. When the number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (a1) is 500 or more, the release properties of the release layer can be improved. When the number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (a1) is 50000 or less, the reduction in elongation of the release layer can be reduced.

[0086] The number-average molecular weight (Mn) of siloxane-bonded (meth)acrylic acid monomers is a value obtained by converting the molecular weight measured by gel permeation chromatography (GPC) to polystyrene. For example, it can be determined under the following conditions: The siloxane-bonded (meth)acrylic acid monomer is dissolved in tetrahydrofuran to obtain a test sample with a concentration of 2.0 g / L. This test sample can be used to determine the number-average molecular weight of the siloxane-bonded (meth)acrylic acid monomer using a gel permeation chromatography (GPC) instrument equipped with a refractive index detector (RID) under the following apparatus and conditions.

[0087] Measuring apparatus: Tosoh Corporation, trade name "HLC-8320GPC"

[0088] Differential refractive index detector: The RI detector built into the above measuring device

[0089] Column: 2 columns, brand name "TSKgel SuperHZM-H" manufactured by Tosoh Corporation

[0090] Mobile phase: Tetrahydrofuran

[0091] Column flow rate: 0.35 mL / min

[0092] Sample concentration: 2.0 g / L

[0093] Injection volume: 10 μL

[0094] Measurement temperature: 40℃

[0095] Molecular weight designation: Standard polystyrene (POLYMER LABORATORIES LTD. standard reference material) (POLYSTYRENE-MEDIUM MOLECULAR WEIGHT CALIBRATION KIT)

[0096] The content of siloxane-bonded (meth)acrylic acid monomer (a1) units in the (meth)acrylic acid polyol (A) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, more preferably 1% by mass or more, and more preferably 3% by mass or more. The content of siloxane-bonded (meth)acrylic acid monomer (a1) units in the (meth)acrylic acid polyol (A) is preferably less than 12.1% by mass, more preferably less than 12% by mass, more preferably 11% by mass or less, more preferably 10% by mass or less, and more preferably 8% by mass or less. By keeping the content of siloxane-bonded (meth)acrylic acid monomer (a1) units within the above range, the reduction in the elongation of the release layer can be reduced.

[0097] (Hydroxy-containing (meth)acrylic acid monomers (a2))

[0098] Preferably, the (meth)acrylic polyol (A) further comprises a hydroxyl-containing (meth)acrylic monomer (a2) unit. That is, the (meth)acrylic polyol (A) is preferably a polymer of (meth)acrylic monomers comprising a siloxane-bonded (meth)acrylic monomer (a1) and a hydroxyl-containing (meth)acrylic monomer (a2). By using the hydroxyl-containing (meth)acrylic monomer (a2), hydroxyl groups can be introduced into the (meth)acrylic polyol (A).

[0099] Examples of hydroxyl-containing (meth)acrylic monomers (a2) include hydroxyalkyl (meth)acrylic esters. The hydroxyl-containing (meth)acrylic monomer (a2) preferably does not contain siloxane bonds. Therefore, the hydroxyl-containing (meth)acrylic monomer (a2) preferably does not contain the structural unit (S1) with siloxane bonds shown in formula (1) above.

[0100] Specific examples of hydroxyl-containing (meth)acrylic monomers (a2) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylaurate (meth)acrylate. Among these, 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate are preferred, and 2-hydroxyethyl (meth)acrylate is more preferred. It should be noted that hydroxyl-containing (meth)acrylic monomers (a2) can be used alone or in combination of two or more.

[0101] The content of hydroxyl-containing (meth)acrylic acid monomer (a2) units in (meth)acrylic acid polyol (A) is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The content of hydroxyl-containing (meth)acrylic acid monomer (a2) units in (meth)acrylic acid polyol (A) is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. By making the content of hydroxyl-containing (meth)acrylic acid monomer (a2) units 1% by mass or more, urethane bonds can be appropriately formed when (meth)acrylic acid polyol (A) reacts with polyisocyanate (I), thereby reducing the decrease in the elongation of the release layer. By making the content of hydroxyl-containing (meth)acrylic acid monomer (a2) units 50% by mass or less, the compatibility of (meth)acrylic acid polyol (A) with other components can be maintained, and the high elongation of the release layer can be maintained.

[0102] (Meth)acrylic monomers with hydrocarbon groups (a3)

[0103] Preferably, the (meth)acrylic polyol (A) further comprises a (meth)acrylic monomer (a3) ​​unit having a hydrocarbon group. That is, the (meth)acrylic polyol (A) is preferably a polymer of (meth)acrylic monomers comprising a (meth)acrylic monomer (a1) containing a siloxane bond, a (meth)acrylic monomer (a2) containing a hydroxyl group, and a (meth)acrylic monomer (a3) ​​having a hydrocarbon group.

[0104] The (meth)acrylic monomer (a3) ​​having a hydrocarbon group preferably does not contain a hydroxyl group. The (meth)acrylic monomer (a3) ​​having a hydrocarbon group preferably does not contain a siloxane bond. Therefore, the (meth)acrylic monomer (a3) ​​having a hydrocarbon group preferably does not contain the structural unit (S1) with a siloxane bond shown in the above formula (1).

[0105] The hydrocarbon group of the (meth)acrylic acid monomer (a3) ​​can be any hydrocarbon group that is linear, branched, or cyclic. The hydrocarbon group of the (meth)acrylic acid monomer (a3) ​​is preferably a linear or branched alkyl group or a cyclic hydrocarbon group, and more preferably a linear or branched alkyl group.

[0106] Specific examples of (meth)acrylic monomers (a3) ​​having a hydrocarbon group include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, and decyl methacrylate; and alkyl methacrylates having cyclic hydrocarbon groups such as benzyl methacrylate, dicyclopentadienyl methacrylate, cyclohexyl methacrylate, 4-butylcyclohexyl methacrylate, dicyclopentene methacrylate, dicyclopentene methacrylate, isobornyl methacrylate, and tricyclodecyl methacrylate. Alkyl methacrylates are preferred, and methyl methacrylate and n-butyl methacrylate are more preferred. (Meth)acrylic monomers (a3) ​​with hydrocarbon groups can be used alone or in combination of two or more.

[0107] The content of hydrocarbon-containing (meth)acrylic acid monomer (a3) ​​units in the (meth)acrylic acid polyol (A) is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. The content of hydrocarbon-containing (meth)acrylic acid monomer (a3) ​​units in the (meth)acrylic acid polyol (A) is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. By making the content of hydrocarbon-containing (meth)acrylic acid monomer (a3) ​​units 40% by mass or more, the (meth)acrylic acid polyol (A) easily migrates into the interior of the release layer, thereby reducing the decrease in the elongation of the release layer. By making the content of hydrocarbon-containing (meth)acrylic acid monomer (a3) ​​units 95% by mass or less, the release properties and elongation of the release layer can be improved.

[0108] The content of (meth)acrylic acid polyol (A) in the polyol (P) is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. The content of (meth)acrylic acid polyol (A) in the polyol (P) is preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less. By keeping the content of (meth)acrylic acid polyol (A) within the above range, the reduction in the elongation of the release layer can be reduced.

[0109] [(Meth)acrylic acid polyol (B)]

[0110] The polyol (P) contained in the main agent includes (meth)acrylic polyol (B). (Meth)acrylic polyol (B) contains structural units (S1) with siloxane bonds as shown in formula (1) above.

[0111] The content of the structural unit (S1) with siloxane bonds shown in formula (1) above in the (meth)acrylic polyol (B) is 12% by mass or more, preferably 15% by mass or more, more preferably 19% by mass or more, and even more preferably 21% by mass or more. By making the content of the structural unit (S1) 12% by mass or more, the (meth)acrylic polyol (B) easily migrates to the surface of the release layer, and the content of siloxane bonds on the surface of the release layer increases, thereby improving the release properties of the release layer.

[0112] The content of the structural unit (S1) with siloxane bonds shown in formula (1) above in the (meth)acrylic polyol (B) is 30% by mass or less, preferably 28% by mass or less. By making the content of the structural unit (S1) 30% by mass or less, as described below, the performance degradation of the semiconductor package caused by the exudation of (meth)acrylic polyol (B) to the surface of the release layer can be reduced.

[0113] The release layer can be formed by reacting the polyol (P) contained in the main agent with the polyisocyanate (I) contained in the curing agent. Sometimes, unreacted (meth)acrylic polyol (B) remains in the final release layer. During semiconductor sealing processes, when the release sheet is heated, the (meth)acrylic polyol (B) remaining in the release layer may sometimes seep to the surface of the release layer. Furthermore, when using a (meth)acrylic monomer (b1) containing siloxane bonds as a raw material for (meth)acrylic polyol (B), the (meth)acrylic monomer (b1) containing siloxane bonds may sometimes contain low-molecular-weight siloxanes such as non-functional cyclic siloxanes generated as byproducts during its synthesis. Sometimes, such low-molecular-weight siloxanes may also seep to the surface of the release layer along with the remaining (meth)acrylic polyol (B). If the (meth)acrylic acid polyol (B) and low-molecular-weight siloxanes that ooze out in this way adhere to the semiconductor package, they will cause contamination, contact obstacles, adhesion problems, and surface hydrophobicity, leading to a decrease in the performance of the semiconductor package. To reduce the performance degradation of the semiconductor package caused by the oozing of such siloxane-containing components, the content of the structural unit (S1) in the (meth)acrylic acid polyol (B) is set to below 30% by mass.

[0114] (Meth)acrylic acid polyol (B) is a polymer of (meth)acrylic acid monomers with hydroxyl groups at the ends or side chains. (Meth)acrylic acid polyol (B) can be obtained by polymerizing (meth)acrylic acid monomers in the presence of a free radical polymerization initiator using conventional methods for manufacturing acrylic polymers.

[0115] (B1) (Meth)acrylic monomers containing siloxane bonds)

[0116] Preferably, the (meth)acrylic polyol (B) comprises a (meth)acrylic monomer (b1) unit containing a siloxane bond. That is, the (meth)acrylic polyol (B) is preferably a polymer of a (meth)acrylic monomer containing a (meth)acrylic monomer (b1) containing a siloxane bond.

[0117] The siloxane-bonded (meth)acrylic monomer (b1) preferably comprises the siloxane-bonded structural unit (S1) shown in formula (1) above. It should be noted that the siloxane-bonded structural unit (S1) shown in formula (1) included in the siloxane-bonded (meth)acrylic monomer (b1) can be the same structural unit as the siloxane-bonded structural unit (S1) shown in formula (1) included in the (meth)acrylic polyol (B) above; therefore, detailed description is omitted here. By including the siloxane-bonded (meth)acrylic monomer (b1) with the siloxane-bonded structural unit (S1) shown in formula (1) above, the siloxane-bonded structural unit (S1) shown in formula (1) above can be introduced into the (meth)acrylic polyol (B).

[0118] As for the siloxane-bonded (meth)acrylic monomer (b1), any known monomer can be used without particular restriction, and the monomer shown in formula (2) above can be cited as an example. It should be noted that the monomer shown in formula (2) above included in the siloxane-bonded (meth)acrylic monomer (b1) is the same as the monomer shown in formula (2) above in the siloxane-bonded (meth)acrylic monomer (a1) of (meth)acrylic polyol (A), therefore, detailed description is omitted here.

[0119] In equation (2), R 5 The alkyl group shown preferably has 1 to 12 carbon atoms, more preferably 1 to 5. As R 5 Examples of alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-heptyl. Methyl, ethyl, and n-butyl are preferred, with n-butyl being more preferred.

[0120] In equation (2), R 6 The alkylene group shown preferably has 1 to 10 carbon atoms, more preferably 1 to 5. As R 6 Examples of alkylene compounds include methylene, ethylene, n-propylene, and n-butylene. Among these, n-propylene (-CH2-CH2-CH2-) is preferred.

[0121] In formula (2), p is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In formula (2), p is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less.

[0122] Furthermore, the monomer shown in formula (3) above is also preferably used as the (meth)acrylic monomer (b1) containing a siloxane bond. The monomer shown in formula (3) above is the same as the monomer shown in formula (3) above in the (meth)acrylic monomer (a1) containing a siloxane bond of the (meth)acrylic polyol (A), so detailed description is omitted here.

[0123] In equation (3), R 9 and R 10 The number of carbon atoms in each of the alkylene groups shown is preferably 1 to 10, more preferably 1 to 5. As R 9 and R 10 Examples of the alkylene groups shown include methylene, ethylene, n-propylene, and n-butylene. It should be noted that R... 9 and R 10 They can be the same or different.

[0124] In formula (3), q is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In formula (3), q is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less.

[0125] Specific examples of (meth)acrylic monomers (b1) containing siloxane bonds include α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane, α-mono(methacryloyloxymethyl)polydimethylsiloxane, and α,ω-di(methacryloyloxymethyl)polydimethylsiloxane.

[0126] The siloxane-bonded (meth)acrylic monomer (b1) preferably comprises at least one of the monomers shown in formula (2) and formula (3) above, and may also comprise both monomers. Among them, the siloxane-bonded (meth)acrylic monomer (b1) is preferably the monomer shown in formula (2) above, and more preferably α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane. The siloxane-bonded (meth)acrylic monomer (b1) can be used alone or in combination of two or more.

[0127] The number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (b1) is preferably 500 or more, more preferably 1000 or more, more preferably 5000 or more, and more preferably 8500 or more. The number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (b1) is preferably 50000 or less, more preferably 25000 or less, and more preferably 15000 or less. When the number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (b1) is 500 or more, the release properties of the release layer can be improved. When the number average molecular weight (Mn) of the siloxane-bonded (meth)acrylic monomer (b1) is 50000 or less, the reduction in elongation of the release layer can be reduced.

[0128] The content of siloxane-bonded (meth)acrylic acid monomer (b1) units in (meth)acrylic acid polyol (B) is preferably 12% by mass or more, more preferably 15% by mass or more, more preferably 19% by mass or more, and more preferably 21% by mass or more. The content of siloxane-bonded (meth)acrylic acid monomer (b1) units in (meth)acrylic acid polyol (B) is preferably 30% by mass or less, more preferably 28% by mass or less. By making the content of siloxane-bonded (meth)acrylic acid monomer (b1) units 12% by mass or more, the release properties of the release layer can be improved. By making the content of siloxane-bonded (meth)acrylic acid monomer (b1) units 30% by mass or less, the exudation of (meth)acrylic acid polyol (B) to the surface of the release layer can be reduced.

[0129] (Hydroxy-containing (meth)acrylic monomers (b2))

[0130] Preferably, the (meth)acrylic polyol (B) further comprises a hydroxyl-containing (meth)acrylic monomer (b2) unit. That is, the (meth)acrylic polyol (B) is preferably a polymer of (meth)acrylic monomers comprising a siloxane-bonded (meth)acrylic monomer (b1) and a hydroxyl-containing (meth)acrylic monomer (b2). By using the hydroxyl-containing (meth)acrylic monomer (b2), hydroxyl groups can be introduced into the (meth)acrylic polyol (B).

[0131] Examples of hydroxyl-containing (meth)acrylic monomers (b2) include hydroxyalkyl (meth)acrylic esters. The hydroxyl-containing (meth)acrylic monomer (b2) preferably does not contain siloxane bonds. Therefore, the hydroxyl-containing (meth)acrylic monomer (b2) preferably does not contain the structural unit (S1) with siloxane bonds shown in formula (1) above.

[0132] As a specific example of a hydroxyl-containing (meth)acrylic acid monomer (b2), the same structural unit as that described above for a hydroxyl-containing (meth)acrylic acid monomer (a2) can be given. Preferably, 4-hydroxybutyl (meth)acrylic acid and 2-hydroxyethyl (meth)acrylic acid are used, more preferably 2-hydroxyethyl (meth)acrylic acid. It should be noted that the hydroxyl-containing (meth)acrylic acid monomer (b2) can be used alone or in combination of two or more.

[0133] The content of hydroxyl-containing (meth)acrylic acid monomer (b2) units in (meth)acrylic acid polyol (B) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The content of hydroxyl-containing (meth)acrylic acid monomer (b2) units in (meth)acrylic acid polyol (B) is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. By making the content of hydroxyl-containing (meth)acrylic acid monomer (b2) units 1% by mass or more, urethane bonds can be appropriately formed when (meth)acrylic acid polyol (B) reacts with polyisocyanate (I), thereby reducing the decrease in the elongation of the release layer. By making the content of hydroxyl-containing (meth)acrylic acid monomer (b2) units 50% by mass or less, the compatibility of (meth)acrylic acid polyol (B) with respect to other components can be maintained, and high elongation of the release layer can be maintained.

[0134] (Meth)acrylates (b3) with hydrocarbon groups

[0135] Preferably, the (meth)acrylic polyol (B) further comprises a (meth)acrylate (b3) unit having a hydrocarbon group. That is, the (meth)acrylic polyol (B) is preferably a polymer of (meth)acrylic monomers comprising a (meth)acrylic monomer (b1) containing a siloxane bond, a (meth)acrylic monomer (b2) containing a hydroxyl group, and a (meth)acrylate (b3) having a hydrocarbon group.

[0136] The (meth)acrylate (b3) having a hydrocarbon group preferably does not contain a hydroxyl group. The (meth)acrylate (b3) having a hydrocarbon group preferably does not contain a siloxane bond. Therefore, the (meth)acrylate (b3) having a hydrocarbon group preferably does not contain the structural unit (S1) with a siloxane bond shown in the above formula (1).

[0137] The hydrocarbon group of (meth)acrylate (b3) containing a hydrocarbon group can be any hydrocarbon group that is straight-chain, branched, or cyclic. The hydrocarbon group of (meth)acrylate (b3) containing a hydrocarbon group is preferably a straight-chain or branched alkyl group or a cyclic hydrocarbon group, and more preferably a straight-chain or branched alkyl group.

[0138] As a specific example of a (meth)acrylate (b3) having a hydrocarbon group, the same structural unit as that described above in the (meth)acrylate (a3) ​​having a hydrocarbon group can be given. Alkyl (meth)acrylate is preferred, and methyl (meth)acrylate and n-butyl (meth)acrylate are more preferred. The (meth)acrylate (b3) having a hydrocarbon group can be used alone or in combination of two or more.

[0139] The content of hydrocarbon-containing (meth)acrylate (b3) units in (meth)acrylate polyol (B) is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more. The content of hydrocarbon-containing (meth)acrylate (b3) units in (meth)acrylate polyol (B) is preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. By ensuring that the content of hydrocarbon-containing (meth)acrylate (b3) units is 20% by mass or more, the compatibility of (meth)acrylate polyol (B) with other components can be maintained, and the reduction in the elongation of the release layer can be reduced. By ensuring that the content of hydrocarbon-containing (meth)acrylate (b3) units is 85% by mass or less, the release properties and elongation of the release layer can be improved.

[0140] The content of (meth)acrylic acid polyol (B) in the polyol (P) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The content of (meth)acrylic acid polyol (B) in the polyol (P) is preferably 40% by mass or less, more preferably 37% by mass or less, and even more preferably 35% by mass or less. By making the content of (meth)acrylic acid polyol (B) 1% by mass or more, the release properties of the release layer can be improved. By making the content of (meth)acrylic acid polyol (B) 40% by mass or less, the exudation of (meth)acrylic acid polyol (B) to the surface of the release layer can be reduced.

[0141] The total content of (meth)acrylic polyols (A) and (B) in the polyol (P) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 18% by mass or more. The total content of (meth)acrylic polyols (A) and (B) in the polyol (P) is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 88% by mass or less. By making the total content of (meth)acrylic polyols (A) and (B) 10% by mass or more, the release properties of the release layer can be improved. By making the total content of (meth)acrylic polyols (A) and (B) 95% by mass or less, the elongation of the release layer can be improved.

[0142] In the polyol (P), the content ratio of (meth)acrylic polyol (A) to (meth)acrylic polyol (B) [mass of (meth)acrylic polyol (A) / mass of (meth)acrylic polyol (B)] is preferably 0.2 or more, more preferably 0.3 or more, more preferably 1 or more, more preferably 1.5 or more, more preferably 2.0 or more, more preferably 2.5 or more, and more preferably 3.0 or more. In the polyol (P), the content ratio of (meth)acrylic polyol (A) to (meth)acrylic polyol (B) [mass of (meth)acrylic polyol (A) / mass of (meth)acrylic polyol (B)] is preferably 70 or less, more preferably 65 or less, more preferably 60 or less, more preferably 50 or less, more preferably 40 or less, more preferably 30 or less, more preferably 20 or less, and more preferably 10 or less. When the content ratio of (meth)acrylic polyol (A) to (meth)acrylic polyol (B) [mass of (meth)acrylic polyol (A) / mass of (meth)acrylic polyol (B)] is 0.2 or higher, the elongation of the release layer is improved. Furthermore, the exudation of (meth)acrylic polyol (B) to the surface of the release layer is reduced. When the content ratio of (meth)acrylic polyol (A) to (meth)acrylic polyol (B) [mass of (meth)acrylic polyol (A) / mass of (meth)acrylic polyol (B)] is 70 or lower, the release properties of the release layer are improved.

[0143] [Other polyols]

[0144] In addition to the (meth)acrylic acid polyols (A) and (B) mentioned above, the polyols (P) contained in the main agent preferably also include other polyols. Examples of other polyols include polyester polyols, polyether polyols, polycarbonate polyols, and alkyl polyols. Polyester polyols, polyether polyols, and polycarbonate polyols are preferred. Using these polyols can improve the release properties and elongation of the release layer. Other polyols can be used alone or in combination of two or more.

[0145] (Polyester polyols)

[0146] Examples of polyester polyols include:

[0147] Lactone-based polyester polyols obtained by ring-opening polymerization of lactones and low molecular weight polyols (1);

[0148] Alcohol-modified lactone-based polyester polyol (2) obtained by copolymerizing diol with lactone-based polyester polyol (1); and

[0149] Polycondensation polyester polyols (3) are products of polycondensation reaction between low molecular weight polyols and polyacids; etc.

[0150] Lactone-based polyester polyols (1) can be obtained by ring-opening polymerization of lactones with low molecular weight polyols as initiators.

[0151] Examples of low molecular weight polyols include compounds having two or more hydroxyl groups and a molecular weight of less than 400, preferably less than 300. Examples of low molecular weight polyols include: ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentanediol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dihydroxymethylheptane, alkane (C7~20) diols, 1,3- or 1,4-cyclohexanediol and mixtures thereof, 1,3- or 1,4-cyclohexanediol and mixtures thereof, hydrogenated bisphenol A, 1,4- Diols such as dihydroxy-2-butene, 2,6-dimethyl-1-octen-3,8-diol, bisphenol A, diethylene glycol, triethylene glycol, and dipropylene glycol; triols such as glycerol, trimethylolpropane, and triisopropanolamine; tetraols such as tetramethylolmethane (pentaerythritol) and diglycerides; pentols such as xylitol; hexaols such as sorbitol, mannitol, allitol, idotitol, galactitol, altritol, inositol, and dipentaerythritol; heptols such as avocadool; and octaols such as sucrose. Low molecular weight polyols can be used alone or in combination of two or more.

[0152] Examples of lactones include ε-caprolactone and γ-valerolactone. Lactones can be used alone or in combination of two or more. Examples of lactone-based polyester polyols (1) include polycaprolactone polyols obtained by ring-opening polymerization of ε-caprolactone and low molecular weight polyols, and polyvalerolactone polyols obtained by ring-opening polymerization of γ-valerolactone and low molecular weight polyols.

[0153] As a lactone-based polyester polyol (1), polycaprolactone polyol is preferred, and polycaprolactone triol obtained by ring-opening polymerization of ε-caprolactone and low molecular weight triol, or polycaprolactone diol obtained by ring-opening polymerization of ε-caprolactone and low molecular weight diol are more preferred.

[0154] Condensation-polymerized polyester polyols (3) can be obtained by condensing low molecular weight polyols with polyacids.

[0155] As a low molecular weight polyol in condensation polyester polyol (3), examples can be made of the same structural units as the low molecular weight polyols described above in lactone polyester polyol (1).

[0156] Examples of polycarboxylic acids include: oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, 3-methyl-3-ethylglutaric acid, azelaic acid, sebacic acid, and other saturated aliphatic dicarboxylic acids (C11-13); maleic acid, fumaric acid, itaconic acid, and other unsaturated aliphatic dicarboxylic acids; phthalic acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, naphthalenedicarboxylic acid, and other aromatic dicarboxylic acids; hexahydrophthalic acid and other alicyclic dicarboxylic acids; dimer acids, hydrogenated dimer acids, and chlorobridged acids (HET). Other carboxylic acids, such as oxalic acid, succinic anhydride, maleic anhydride, phthalic anhydride, 2-alkyl (C12~C18) succinic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, and acyl halides derived from these carboxylic acids, such as oxaloyl dichloride, adipyl dichloride, sebacate dichloride, etc. Polybasic acids can be used alone or in combination of two or more.

[0157] The content of polyester polyol in polyol (P) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. The content of polyester polyol in polyol (P) is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. By keeping the content of polyester polyol within the above range, the release properties and elongation of the release layer can be improved.

[0158] (Polyether polyols)

[0159] Examples of polyether polyols include aliphatic polyether polyols and alicyclic polyether polyols. Examples of aliphatic polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polyheptamethylene ether glycol, polydemoethylene ether glycol; pentaerythritol, dipentaerythritol, trimethylolpropane, and ethylene oxide addition triols of trimethylolpropane, propylene oxide addition triols of trimethylolpropane, ethylene oxide and propylene oxide addition triols of trimethylolpropane, ethylene oxide addition tetraols of pentaerythritol, ethylene oxide addition hexaols of dipentaerythritol, and other alkylene oxide addition polyols, or polyether polyols obtained by ring-opening polymerization of two or more ionic polymerizable cyclic compounds.

[0160] It should be noted that examples of ionicly polymerizable cyclic compounds include ethylene oxide, propylene oxide, 1,2-epoxybutane, isobutene oxide, 3,3-bis(chloromethyl)oxetane, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl ether, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyloxetane, vinyltetrahydrofuran, vinylcyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, glycidyl benzoate, and other cyclic ethers. Examples of specific combinations of two or more ionicly polymerizable cyclic compounds include tetrahydrofuran with ethylene oxide, tetrahydrofuran with propylene oxide, tetrahydrofuran with 2-methyltetrahydrofuran, tetrahydrofuran with 3-methyltetrahydrofuran, ethylene oxide with propylene oxide, 1,2-epoxybutane with ethylene oxide, and tetrahydrofuran with 1,2-epoxybutane with ethylene oxide.

[0161] Examples of alicyclic polyether polyols include alkylene oxide diols of hydrogenated bisphenol A, alkylene oxide diols of hydrogenated bisphenol F, and alkylene oxide diols of 1,4-cyclohexanediol.

[0162] The content of polyether polyol in polyol (P) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. On the other hand, the content of polyether polyol in polyol (P) is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. By keeping the content of polyether polyol within the above range, the release properties and elongation of the release layer can be improved.

[0163] (Polycarbonate polyols)

[0164] Examples of polycarbonate polyols include ring-opening polymers of ethylene carbonate in which the aforementioned low molecular weight polyol is used as an initiator in a lactone-based polyester polyol (1), or amorphous polycarbonate polyols obtained by copolymerizing diols such as 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol with a ring-opening polymer.

[0165] Examples of polycarbonate polyols include polyhexamethylene carbonate diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, poly(tetramethylene / hexamethylene) carbonate diol, and poly[cyclohexene bis(methylene) / hexamethylene] carbonate diol. It should be noted that poly(tetramethylene / hexamethylene) carbonate diol is a copolymer of 1,4-butanediol and 1,6-hexanediol with dialkyl carbonates. Additionally, poly[cyclohexene bis(methylene) / hexamethylene] carbonate diol is a copolymer of 1,4-cyclohexanediol and 1,6-hexanediol with dialkyl carbonates.

[0166] The content of polycarbonate polyol in the polyol (P) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. On the other hand, the content of polycarbonate polyol in the polyol (P) is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. By keeping the content of polycarbonate polyol within the above range, the release properties and elongation of the release layer can be improved.

[0167] (alkyl polyols)

[0168] Alkyl polyols are compounds formed in which at least two hydrogen atoms in a molecule of a chain or saturated hydrocarbon with a saturated alicyclic structure are replaced by hydroxyl groups (-OH).

[0169] In chain-like saturated hydrocarbons, compounds formed by replacing at least two hydrogen atoms in one molecule with hydroxyl groups (-OH) are called "chain-like alkyl polyols".

[0170] In saturated hydrocarbons with a saturated alicyclic structure, compounds formed by replacing at least two hydrogen atoms in one molecule with hydroxyl groups (-OH) are called "cycloalkyl polyols".

[0171] It should be noted that "saturated alicyclic structure" refers to an alicyclic structure that does not contain unsaturated bonds such as carbon-carbon double bonds or carbon-carbon triple bonds. Examples of saturated alicyclic structures include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cyclooctane, and cyclodecane, as well as tetrahydrodicyclopentadiene and adamantane. Additionally, examples of saturated hydrocarbons with saturated alicyclic structures include dimethylcyclohexane, diethylcyclohexane, adamantane, tetrahydrodicyclopentadiene, and tetramethylcyclobutane.

[0172] In alkyl polyols, the number of hydroxyl groups per molecule is two or more. Furthermore, in alkyl polyols, the number of hydroxyl groups per molecule is preferably five or less, more preferably three or less. Alkyl polyols are particularly preferably found to have two hydroxyl groups per molecule.

[0173] Specifically, examples of alkyl polyols include:

[0174] Propylene glycol, butanediol, pentanediol, hexanediol, heptahydrate, octanediol, nonanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2-methyl-1,6-hexanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,3,5-trimethyl-1,3-pentanediol, and 2,2,4-trimethyl-1,6-hexanediol, and other chain alkyl polyols; and

[0175] Cyclohexanediethanol, including 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, and 1,4-cyclohexanediethanol; cyclohexanediethanol, including 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, and 1,4-cyclohexanediethanol; tricyclodecanediethanol; adamantanediol; and 2,2,4,4-tetramethyl-1,3-cyclobutanediol; and other cycloalkyl polyols. Alkyl polyols can be used alone or in combination of two or more.

[0176] The content of alkyl polyols in the polyol (P) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. On the other hand, the content of alkyl polyols in the polyol (P) is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. By keeping the content of alkyl polyols within the above range, the release properties and elongation of the release layer can be improved.

[0177] [Curing agent]

[0178] The two-component curable coating agent of the present invention comprises a curing agent containing a polyisocyanate (I). The polyisocyanate (I) has two or more isocyanate groups (-NCO) in one molecule, preferably three or more.

[0179] The polyisocyanate (I) may not have the structural unit (S2) with siloxane bonds shown in formula (4) below, but it is preferred to have it. It should be noted that "the structural unit (S2) with siloxane bonds shown in formula (4) below" is sometimes simply referred to as "structural unit (S2)".

[0180] [Chemical Formula 5]

[0181]

[0182] (In equation (4), R) 12 and R 13Each atom represents a hydrogen atom or a monovalent hydrocarbon group independently; * indicates a bonding site (single bond).

[0183] In equation (4), R 12 and R 13 Each can be an independent hydrogen atom or a monovalent hydrocarbon group. R 12 and R 13 They can be the same or different, but being the same is preferred. Examples of monovalent hydrocarbon groups include alkyl, cycloalkyl, and aryl groups. Among them, alkyl is preferred.

[0184] The alkyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 10, even more preferably 1 to 6, and even more preferably 1 to 3. Examples of alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl. Among these, methyl and ethyl are preferred, and methyl is more preferred.

[0185] The cycloalkyl group preferably has 3 to 10 carbon atoms, more preferably 5 to 10, and even more preferably 5 or 6. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0186] The aryl group preferably has 6 to 14 carbon atoms, more preferably 6 to 10, and even more preferably 6 to 8. Examples of aryl groups include phenyl, naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, and 3-isopropylphenyl.

[0187] The content of the siloxane-bonded structural unit (S2) shown in formula (4) above in the polyisocyanate (I) is preferably 0.5% by mass or more, more preferably 1% by mass or more, more preferably 10% by mass or more, more preferably 20% by mass or more, more preferably 25% by mass or more, and more preferably 30% by mass or more. By making the content of the siloxane-bonded structural unit (S2) shown in formula (4) above 0.5% by mass or more, the release properties of the release layer can be improved.

[0188] The content of the siloxane bond-containing structural unit (S2) shown in formula (4) above in the polyisocyanate (I) is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. By making the content of the structural unit (S2) 50% by mass or less, as described below, the performance degradation of the semiconductor package caused by the exudation of the polyisocyanate (I) containing the structural unit (S2) can be reduced.

[0189] The release layer can be formed by reacting the polyol (P) contained in the main agent with the polyisocyanate (I) contained in the curing agent. Sometimes, unreacted polyisocyanate (I) containing structural unit (S2) remains in the final release layer. When the release sheet is heated during the semiconductor sealing process, the polyisocyanate (I) containing structural unit (S2) remaining in the release layer may sometimes seep to the surface of the release layer. In addition, when a polyol having a siloxane bond structural unit (S2) as shown in the above formula (4) is used as the raw material for polyisocyanate (I), low-molecular-weight siloxanes such as non-functional cyclic siloxanes generated as byproducts during its synthesis may sometimes be mixed in with the polyol. Sometimes, such low-molecular-weight siloxanes may also seep to the surface of the release layer together with the residual polyisocyanate (I) containing structural unit (S2). If the polyisocyanate (I) or low-molecular-weight siloxane that seeps out in this way adheres to the semiconductor package, it will cause contamination, contact obstacles, adhesion obstacles, and surface hydrophobicity in the semiconductor package, thus leading to a decrease in the performance of the semiconductor package. In order to reduce such performance degradation of the semiconductor package, it is preferable to set the content of the structural unit (S2) in the polyisocyanate (I) to 50% by mass or less.

[0190] It should be noted that when polyisocyanate (I) includes polyisocyanate (C) without structural unit (S2) and polyisocyanate (D) with structural unit (S2) as described later, the content of the structural unit (S2) with siloxane bond shown in the above formula (4) in polyisocyanate (I) refers to the ratio of the total mass of the structural unit (S2) with siloxane bond shown in the above formula (4) to the total mass of the various polyisocyanates.

[0191] As for the determination of the content of the siloxane bond structural unit (S2) shown in the above formula (4) in polyisocyanate (I), the same method as the method described above for determining the content of the siloxane bond structural unit (S1) shown in the above formula (1) in (meth)acrylic polyol can be used.

[0192] Polyisocyanate (I) may also lack the structural unit (S2). Therefore, polyisocyanate (I) may contain only polyisocyanate (C) without the structural unit (S2). Alternatively, polyisocyanate (I) preferably contains the structural unit (S2). In such cases, polyisocyanate (I) preferably contains polyisocyanate (D) with the structural unit (S2), and more preferably contains both polyisocyanate (C) without the structural unit (S2) and polyisocyanate (D) with the structural unit (S2). According to polyisocyanate (D) with the structural unit (S2), the release properties of the release layer can be improved.

[0193] Specific examples of polyisocyanates (C) that do not have a structural unit (S2) include aliphatic polyisocyanates that do not have a structural unit (S2), polyisocyanates with an alicyclic structure that do not have a structural unit (S2), and modified forms of these polyisocyanates. Polyisocyanates (C) that do not have a structural unit (S2) can be used alone or in combination of two or more.

[0194] Examples of aliphatic polyisocyanates lacking a structural unit (S2) include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, methyl 2,6-diisocyanatomethyl caproate, bis(2-isocyanoethyl) fumarate, bis(2-isocyanoethyl) carbonate, and 2-isocyanoethyl-2,6-diisocyanate hexanoate. Hexamethylene diisocyanate is preferred among these acyclic aliphatic polyisocyanates.

[0195] Examples of polyisocyanates with alicyclic structures that do not have a structural unit (S2) include 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate, methylcyclohexyl diisocyanate (hydrogenated TDI), and 1,3-bis(isocyanomethyl)cyclohexane (hydrogenated m-XDI).

[0196] Examples of modified polyisocyanates lacking the structural unit (S2) include isocyanurate esters, biuret esters, and adducts of the aforementioned polyisocyanates lacking the structural unit (S2). Polyisocyanates can form isocyanurate esters or biuret esters in triplicate. Examples of adducts include adducts of polyisocyanates with polyols lacking siloxane bonds. For instance, a trimer adduct can be formed by reacting trimethylolpropane with three molecules of polyisocyanate.

[0197] Examples of modified polyisocyanates that do not have a structural unit (S2) include:

[0198] Biuret forms and isocyanurate forms of aliphatic polyisocyanates that do not have a structural unit (S2), such as ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and dodecamethylene diisocyanate.

[0199] Biuret forms and isocyanurate forms of polyisocyanates with alicyclic structures that do not have a structural unit (S2), such as 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate, methylcyclohexyl diisocyanate (hydrogenated TDI), and 1,3-bis(isocyanomethyl)cyclohexane (hydrogenated m-XDI);

[0200] Trimeric adduct of trimethylolpropane (TMP) and hydrogenated MDI;

[0201] Trimeric adduct formed by 3 moles of any one of the polyisocyanates, such as isophorone diisocyanate, methyl cyclohexyl diisocyanate (hydrogenated TDI), and 1,3-bis(isocyanomethyl)cyclohexane (hydrogenated m-XDI), with 1 mole of trimethylolpropane (TMP).

[0202] The adduct formed by trimethylolpropane (TMP) with 2 moles of isophorone diisocyanate and 1 mole of hexamethylene diisocyanate (HDI); and

[0203] Adducts formed by diols that do not have a structural unit (S2) with aliphatic diisocyanates such as ethylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate, which do not have a structural unit (S2), namely, 2-functional polyurethane diisocyanates.

[0204] Examples of polyisocyanates (C) lacking the structural unit (S2) include aliphatic polyisocyanates lacking the structural unit (S2) described above, polyisocyanates with an alicyclic structure lacking the structural unit (S2), and their modified forms (isocyanurate forms, biuret forms, and adducts). Preferably, isocyanurate forms, biuret forms, and adducts of aliphatic polyisocyanates lacking the structural unit (S2) are preferred; more preferably, adducts of diols lacking the structural unit (S2) and aliphatic diisocyanates lacking the structural unit (S2) are preferred; and even more preferably, adducts of diols lacking the structural unit (S2) and 1,6-hexamethylene diisocyanate are preferred. Polyisocyanates (C) lacking the structural unit (S2) can be used alone or in combination of two or more.

[0205] As a polyisocyanate (D) having a structural unit (S2), a preferred example is a polyisocyanate (D) that is a reaction product of a polyisocyanate and a polyol having a structural unit (S2) having a siloxane bond as shown in formula (4) above. Preferably, a polyisocyanate (D) having two or more isocyanate groups and having a structural unit (S2) having a siloxane bond as shown in formula (4) above is obtained by reacting the isocyanate group of the polyisocyanate with each of the hydroxyl groups of the polyol having a structural unit (S2) having a siloxane bond as shown in formula (4) above to form a urethane bond. The polyisocyanate (D) having the structural unit (S2) can be used alone or in combination of two or more.

[0206] As a polyisocyanate constituting polyisocyanate (D), examples include polyisocyanates that do not have a structural unit (S2). Specific examples of polyisocyanates that do not have a structural unit (S2) include aliphatic polyisocyanates, polyisocyanates with an alicyclic structure that do not have a structural unit (S2), and modified forms of these polyisocyanates. These specific examples are the same as those described above for polyisocyanate (C) that does not have a structural unit (S2), therefore detailed descriptions are omitted here. The polyisocyanates constituting polyisocyanate (D) can be used alone or in combination of two or more.

[0207] As a structural unit (S2) in a polyol, the same structural unit (S2) as the "structural unit (S2) with siloxane bond shown in the above formula (4)" in polyisocyanate (I) can be cited, so detailed description is omitted here.

[0208] As a polyol having a structural unit (S2), the polyol shown in the following formula (5) is preferably exemplified.

[0209] [Chemical Formula 6]

[0210]

[0211] (In equation (5), R) 14 R 15 R 16 and R 17 They can be the same or different, and are alkylene groups with 1 to 10 carbon atoms, where m represents an integer greater than 2.

[0212] In equation (5), R 14 R 15 R 16 and R 17The number of carbon atoms in the alkylene group shown is preferably 1 to 10, more preferably 1 to 5. Examples of alkylene groups include methylene, ethylene, n-propylene, and n-butylene.

[0213] In formula (5), m is preferably 2 or more, more preferably 5 or more, and even more preferably 10 or more. In formula (5), m is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less.

[0214] The number-average molecular weight (Mn) of the polyol having the structural unit (S2) is preferably 500 or more, more preferably 1000 or more, and even more preferably 5000 or more. The number-average molecular weight (Mn) of the polyol having the structural unit (S2) is preferably 25000 or less, more preferably 15000 or less, and even more preferably 9000 or less. When the number-average molecular weight (Mn) of the polyol is 500 or more, the release properties of the release layer can be improved. When the number-average molecular weight (Mn) of the polyol is 25000 or less, the reduction in elongation of the release layer can be reduced.

[0215] It should be noted that the number-average molecular weight (Mn) of polyols having structural unit (S2) can be determined using the same method described above for the number-average molecular weight (Mn) of (meth)acrylic acid monomers containing siloxane bonds.

[0216] As a polyisocyanate (D) having a structural unit (S2), the preferred product is the reaction product of an isocyanurate body of an aliphatic polyisocyanate without a structural unit (S2) and a polyol having a structural unit (S2), and more preferably, the reaction product of an isocyanurate body of hexamethylene diisocyanate and a polyol having a structural unit (S2). Preferably, a polyisocyanate (D) having two or more isocyanate groups and a structural unit (S2) is obtained by reacting the isocyanate groups of the polyisocyanate with the hydroxyl groups of the polyol having a structural unit (S2) to form a carbamate bond.

[0217] In the production of polyisocyanate (D), polyisocyanate (D) having two or more isocyanate groups can be produced by reacting excess polyisocyanate with a polyol having a structural unit (S2) through a carbamate reaction. Preferably, different polyisocyanates are reacted with the hydroxyl groups of a polyol having a structural unit (S2) through a carbamate reaction.

[0218] In the carbamate reaction of a polyisocyanate with a polyol having a structural unit (S2), the equivalence ratio (isocyanate group / hydroxyl group) of the isocyanate group to the hydroxyl group of the polyol having a structural unit (S2) is preferably 2.0 or more, more preferably 2.5 or more. In the carbamate reaction of a polyisocyanate with a polyol having a structural unit (S2), the equivalence ratio (isocyanate group / hydroxyl group) of the isocyanate group to the hydroxyl group of the polyol having a structural unit (S2) is preferably 10.0 or less, more preferably 9.0 or less. By setting the equivalence ratio (isocyanate group / hydroxyl group) to 2.0 or more, excess isocyanate groups can undergo carbamate reaction with hydroxyl groups, and a polyisocyanate having two or more isocyanate groups in one molecule can be obtained.

[0219] The equivalence ratio (isocyanate group / hydroxyl group) of the isocyanate group relative to the hydroxyl group of the polyol having the structural unit (S2) is determined by dividing the number of isocyanate groups in the polyisocyanate by the number of hydroxyl groups in the polyol having the structural unit (S2).

[0220] The number of hydroxyl groups in a polyol having a structural unit (S2) is calculated based on the following formula. It should be noted that the hydroxyl value refers to the value obtained by determination according to method 4.2 B of JIS K 1557-1:2007 (ISO 14900:2001) "Plastics - Polyurethane raw materials - Test methods - Part 1: Determination of hydroxyl value".

[0221] The number of hydroxyl groups in a polyol having a structural unit (S2)

[0222] = Amount (g) of polyol with structural unit (S2) used in carbamate reaction × hydroxyl value (mgKOH / g) / 56100

[0223] The number of isocyanate groups in polyisocyanates is calculated based on the following formula. Isocyanate equivalent is the value obtained by dividing the molecular weight of the polyisocyanate by the number of isocyanate groups in one molecule. Specifically, it refers to the value measured according to JIS K 1603.

[0224] Number of isocyanate groups in polyisocyanates

[0225] = Amount of polyisocyanate used in the carbamate reaction (g) / Isocyanate equivalent

[0226] When the polyisocyanate (I) comprises polyisocyanate (C) without structural unit (S2) and polyisocyanate (D) with structural unit (S2), the content of polyisocyanate (C) without structural unit (S2) in polyisocyanate (I) is preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, and more preferably 60% by mass or more. When the polyisocyanate (I) comprises polyisocyanate (C) without structural unit (S2) and polyisocyanate (D) with structural unit (S2), the content of polyisocyanate (C) without structural unit (S2) in polyisocyanate (I) is preferably 99% by mass or less.

[0227] When the polyisocyanate (I) comprises polyisocyanate (C) without structural unit (S2) and polyisocyanate (D) with structural unit (S2), the content of polyisocyanate (D) with structural unit (S2) in polyisocyanate (I) is preferably 1% by mass or more. When the polyisocyanate (I) comprises polyisocyanate (C) without structural unit (S2) and polyisocyanate (D) with structural unit (S2), the content of polyisocyanate (D) with structural unit (S2) in polyisocyanate (I) is preferably 70% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, and more preferably 40% by mass or less. By making the content of polyisocyanate (D) with structural unit (S2) 1% by mass or more, the release properties of the release layer can be improved. By keeping the content of polyisocyanate (D) with structural unit (S2) below 70% by mass, the exudation of polyisocyanate (D) with structural unit (S2) to the surface of the release layer can be reduced.

[0228] In a two-component curable coating agent, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group of the polyisocyanate (I) contained in the curing agent to the hydroxyl group of the polyol (P) contained in the main agent is preferably 0.7 or more, more preferably 0.8 or more. In a two-component curable coating agent, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group of the polyisocyanate (I) contained in the curing agent to the hydroxyl group of the polyol (P) contained in the main agent is preferably 2.5 or less, more preferably 2.0 or less. By keeping the equivalent ratio (isocyanate group / hydroxyl group) within the above range, the reduction in the elongation of the release layer can be reduced.

[0229] It should be noted that the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the curing agent to the hydroxyl group in the polyol (P) contained in the main agent is obtained by dividing the number of isocyanate groups in the total polyisocyanate (I) by the number of hydroxyl groups in the total polyol (P).

[0230] The main component contains various polyols, including (meth)acrylic acid polyol (A) and (B). Therefore, the total number of hydroxyl groups in the polyol (P) is calculated based on the following formula.

[0231] The number of hydroxyl groups in the total polyol (P)

[0232] =(W1×H1 / 56100)+(W2×H2 / 56100)+···+(W m ×H m / 56100)

[0233] (where W) m H represents the content (g) of the m-th polyol in the total polyol (P). m Let m be the hydroxyl value (mgKOH / g) of the m-th polyol, where m is an integer representing the number of polyols.

[0234] In addition, the hydroxyl value of the m-th polyol refers to the value obtained by determination according to method 4.2 B of JIS K 1557-1:2007 (ISO 14900:2001) "Plastics - Polyurethane raw materials - Test methods - Part 1: Determination of hydroxyl value".

[0235] Polyisocyanate (I) sometimes contains multiple polyisocyanates. Therefore, the isocyanate base in polyisocyanate (I) as a whole is a value calculated based on the following formula.

[0236] The number of isocyanate groups in the total polyisocyanate (I)

[0237] =[W1×I1 / (42.02×100)]+[W2×I2 / (42.02×100)]+···+[W n ×I n / (42.02×100)]

[0238] (where W) n Let I be the content (g) of the nth polyisocyanate in the whole polyisocyanate (I). n This represents the content (mass fraction%) of isocyanate groups in the nth polyisocyanate, where n is an integer representing the number of polyisocyanates.

[0239] In addition, the content of isocyanate groups in the nth polyisocyanate can be determined according to method 11A of JIS K1603-1:2007 "Plastics - Aromatic isocyanates - Part 1: Determination of isocyanate group content".

[0240] (particle)

[0241] Two-component curable coating agents preferably further contain particles. Therefore, at least one of the main agent and curing agent in a two-component curable coating agent preferably further contains particles. More preferably, the main agent contains particles. By using particles, an uneven surface can be imparted to the surface of the release layer, improving the release properties of the release layer. Furthermore, the uneven surface of the release layer can be transferred to the surface of the semiconductor package, thereby reducing flow marks on the surface of the semiconductor package due to the sealing resin and improving the appearance of the semiconductor package surface.

[0242] Examples of particles include inorganic particles and resin particles. Examples of inorganic particles include silica particles, alumina particles, titanium dioxide particles, calcium carbonate particles, barium carbonate particles, aluminum silicate particles, alumina particles, zinc oxide particles, magnesium oxide particles, aluminum hydroxide particles, magnesium hydroxide particles, kaolin particles, clay particles, talc particles, quartz particles, diatomaceous earth particles, perlite particles, and bentonite particles. Examples of resin particles include acrylic resin particles, urethane resin particles, olefin resin particles, polystyrene resin particles, epoxy resin particles, polyvinylidene fluoride particles, melamine resin particles, polyacrylonitrile resin particles, and silicone resin particles. Among these, resin particles are preferred, and urethane resin particles are more preferred. These particles are less likely to detach from the release layer. Particles can be used alone or in combination of two or more types.

[0243] The volume average particle size is preferably 1 to 60 μm, more preferably 5 to 30 μm. By keeping the volume average particle size within the above range, it is easy to impart an uneven shape to the surface of the release layer, thereby improving the release properties of the release layer.

[0244] It should be noted that the volume average particle size can be measured using a laser diffraction particle size distribution analyzer (e.g., the "SALD2100" manufactured by Shimadzu Corporation) with the particles dispersed in water.

[0245] Relative to 100 parts by mass of the total amount of polyol (P) in the main agent, polyisocyanate (I) in the curing agent, and particles, the particle content ratio in the two-component curable coating agent is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass. By making the particle content ratio 1 part by mass or more, the surface of the release layer can be sufficiently given an uneven shape. By making the particle content ratio 50 parts by mass or less, the shedding of particles from the release layer can be reduced.

[0246] (Catalyst solidification)

[0247] Two-component curable coatings may contain a curing catalyst. Therefore, it is preferable that at least one of the main component and the curing agent in a two-component curable coating contains a curing catalyst, and more preferably, the main component contains a curing catalyst. Examples of curing catalysts include organometallic compounds such as dibutyltin oxide, tin 2-ethylhexanoate, tin octoate, and dibutyltin dilaurate. The curing catalyst can be used alone or in combination of two or more.

[0248] In two-component curing coatings, additives can be added as needed, within a range that does not impair the physical properties of the two-component curing coating. Examples of additives include antioxidants, light stabilizers, heat stabilizers, antistatic agents, and defoamers.

[0249] Two-component curable coatings may contain solvents. Therefore, at least one of the main component and the curing agent in a two-component curable coating may contain a solvent. When the main component contains a solvent, the solids concentration of the main component is preferably 10-90% by mass, more preferably 20-80% by mass. When the curing agent contains a solvent, the solids concentration of the curing agent is preferably 10-90% by mass, more preferably 20-80% by mass.

[0250] Examples of solvents include hydrocarbons such as pentane, hexane, heptane, and cyclohexane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and esters such as ethyl acetate and butyl acetate. It should be noted that solvents can be used alone or in combination of two or more.

[0251] [Mold Release Sheet]

[0252] The two-component curable coating agent of the present invention is suitable for use in release sheets. Specifically, the release sheet has a support layer and a release layer integrally laminated on one side of the support layer. As the release layer of such a release sheet, the cured film of the two-component curable coating agent of the present invention can be suitably used. Hereinafter, a release sheet formed using the two-component curable coating agent of the present invention will be described.

[0253] (Support layer)

[0254] The release sheet includes a support layer. The support layer preferably includes a synthetic resin. Examples of synthetic resins include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; olefin resins such as acrylic resin and ethylene resin; acrylic resin; cellulose triacetate; polycarbonate; polyamide resin; polystyrene; and nylon. Among these, polyester resins and olefin resins are preferred from the perspective of excellent heat resistance and elongation, more preferably polyester resins, and even more preferably polybutylene terephthalate. The synthetic resin can be used alone or in combination of two or more.

[0255] The support layer may further include additives such as antistatic agents, light stabilizers, inorganic fillers, flame retardants, antioxidants, lubricants, and ultraviolet absorbers. The thickness of the support layer is not particularly limited, but is preferably 5–250 μm, more preferably 10–100 μm.

[0256] A release layer is integrally laminated on one side (surface) of the support layer. To improve the release properties of the release sheet, an uneven shape can be given to the other side (back side) of the support layer opposite to the other side. As a method for giving an uneven shape, known methods such as embossing can be used.

[0257] (release layer)

[0258] The release sheet has a release layer integrally laminated on one side of the support layer. The release layer is a cured film of the two-component curable coating agent of the present invention described above.

[0259] The release layer is integrally laminated to at least one side of the support layer, or it can be integrally laminated to both one side (surface) and the other side (back) of the support layer. When the release layer is integrally laminated to only one side of the support layer, as described above, the other side of the support layer can be given a textured surface to improve release properties.

[0260] The thickness of the release layer is preferably 0.1 to 100 μm, more preferably 5 to 50 μm. By making the thickness of the release layer 0.1 μm or more, sufficient release properties can be imparted to the release layer. By making the thickness of the release layer 100 μm or less, the elongation of the release layer can be maintained.

[0261] The release sheet may have other layers between the release layer and the support layer, or on the release layer. Examples of these other layers include adhesive layers, antistatic layers, and coloring layers. Preferably, the release sheet further has at least one of these other layers. The adhesive layer is used to improve the adhesion between the release layer and the support layer. The adhesive layer preferably comprises known adhesives such as olefin adhesives, polyester adhesives, acrylic adhesives, and fluororubber adhesives.

[0262] Alternatively, the protective sheet can be peelably laminated integrally onto the release layer. The protective sheet is used to prevent scratches and dirt from adhering to the release layer during transportation or storage of the release sheet. Therefore, when using the release sheet, it is preferable to peel off the protective sheet to expose the release layer as the outermost layer of the release sheet.

[0263] Examples of protective sheets include metal foil and resin films. Examples of metal foils include aluminum foil. Examples of resin films include polyethylene terephthalate films, polyethylene films, and polypropylene films. Preferably, the surface of the protective sheet opposite to the release layer is subjected to a release treatment.

[0264] As a method for manufacturing a release layer, the following method (i) can be used: mixing the main component and the curing agent of a two-component curable coating agent, applying the two-component curable coating agent to at least one side of a support layer and heating it, thereby forming a release layer. Preferably, the main component and the curing agent of the two-component curable coating agent are mixed just before the two-component curable coating agent is applied to at least one side of the support layer.

[0265] The two-component curable coating agent is applied to at least one side of the support layer. The two-component curable coating agent can be applied to only one side of the support layer, or to both one side and the other side of the support layer. Furthermore, if other layers such as adhesive layers, antistatic layers, and coloring layers are provided on the support layer, the two-component curable coating agent can simply be applied to these other layers.

[0266] Methods for applying two-component curable coating agents include, for example, coating methods based on dip coating, spray coating, roller coating, doctor blade coating, screen printing, etc., and casting methods using rod coaters, coaters, etc.

[0267] Then, the two-component curable coating agent applied to at least one side of the support layer is heat-cured. Upon heating, the polyol (P) contained in the two-component curable coating agent reacts with the polyisocyanate (I) to form polyurethane, thereby curing the two-component curable coating agent to form a release layer.

[0268] The heating temperature of the two-component curing coating agent is preferably 60~180℃, more preferably 80~150℃. The heating time of the two-component curing coating agent is preferably 1~30 minutes, more preferably 1~10 minutes.

[0269] As a method for manufacturing a release sheet, a method (ii) with the following steps can also be used: mixing the main component and curing agent of a two-component curing coating agent, applying the two-component curing coating agent to the release treatment surface of the protective sheet and heating it to form a release layer; and a step of laminating the release layer onto at least one side of the support layer.

[0270] In the process of forming the release layer, by applying a two-component curable coating agent to the release surface of the protective sheet and heating it, a release layer that can be peeled off and integrally laminated with the protective sheet can be formed. The method of applying the two-component curable coating agent to the release surface of the protective sheet, the heating temperature of the two-component curable coating agent, and the heating time in method (ii) above are the same as in method (i) above, so detailed descriptions are omitted here.

[0271] In the process of integrally laminating the release layer onto at least one side of the support layer, it is preferable to use an adhesive to integrally laminate the release layer onto at least one side of the support layer. As the adhesive, known adhesives such as olefin-based adhesives, polyester-based adhesives, acrylic adhesives, and fluororubber-based adhesives can be used. Thus, the release layer can be integrally laminated onto at least one side of the support layer via an adhesive layer containing the adhesive.

[0272] The release layer can be integrally laminated onto only one side of the support layer, or it can be integrally laminated onto both one and the other side of the support layer. Furthermore, if the support layer has other layers such as an antistatic layer and a coloring layer, the release layer can simply be integrally laminated onto these other layers.

[0273] The release sheet of the present invention can be suitably used as a release sheet for semiconductor packages. A semiconductor package can be obtained, for example, by sealing a semiconductor chip with a sealing resin within a mold in which the release sheet is provided. When using a release sheet having a release layer only on one side of the support layer, it is preferable to place the release sheet within the mold in such a way that the release layer of the release sheet contacts the sealing resin. Either compression molding or transfer molding can be used in the manufacture of the semiconductor package.

[0274] For example, in compression molding, a mold consisting of a lower mold and an upper mold is used to manufacture a semiconductor package. Specifically, firstly, a release liner is placed on the inner surface of the lower mold, and the release liner is sealed to the inner surface of the lower mold by vacuum suction or the like. Meanwhile, a semiconductor chip is placed on the upper mold. Next, a sealing resin is supplied to the inner surface of the lower mold, which has the release liner sealed. Then, the lower and upper molds are closed, and the sealing resin is compressed while being heated to cure it. Thus, the semiconductor chip is sealed by the sealing resin, resulting in a semiconductor package. Then, the mold is opened, and the semiconductor package can be removed from the mold. There are no particular limitations on the sealing resin; thermosetting resins such as epoxy resin can be used appropriately.

[0275] According to the two-component curable coating agent of the present invention, a release layer with excellent release properties and elongation can be formed. Based on the release sheet having such a release layer, due to the excellent elongation of the release layer, the release sheet can be tightly fitted into the mold cavity without cracking during the semiconductor sealing process. In particular, even when the inner surface of the mold cavity has a complex shape or a large difference in elevation, the release sheet can conform and fit tightly along the shape of the inner surface of the mold cavity. Therefore, contamination of the mold caused by the sealing resin can be reduced, resulting in a semiconductor package with excellent appearance. Furthermore, due to the excellent release properties of the release layer, the semiconductor package can be easily removed from the mold after the semiconductor sealing process without damage. At this time, the semiconductor package can also be easily peeled from the release sheet.

[0276] The above description uses a semiconductor package as an example of the application of the release sheet of the present invention. However, the application of the release sheet is not particularly limited. Other applications of the release sheet include release sheets for molding carbon fiber prepregs, ceramic capacitors, etc., release films for transferring printing onto products, and release sheets for protecting adhesive layers of adhesive films, etc.

[0277] [Functional film for transfer printing]

[0278] Furthermore, the release sheet of the present invention can also be used as a functional sheet for transferring functional layers such as hard coatings onto resin molded bodies.

[0279] The transfer sheet has a release sheet and a transfer sheet that is peelably laminated integrally onto the release layer of the release sheet. The transfer sheet comprises a hard coating layer and an adhesive layer, arranged such that the release layer of the release sheet is opposite to the hard coating layer.

[0280] As a release sheet for a functional sheet used in transfer printing, the above-described release sheet can be used. As described above, the release sheet has a support layer and a release layer integrally laminated on one side of the support layer.

[0281] A hard coating is used to impart high hardness and scratch resistance to the surface of a resin-molded body. The hard coating preferably comprises a synthetic resin. There are no particular limitations on the synthetic resin; examples include polyester resins, acrylic resins, urethane resins, amide resins, silicone resins, and epoxy resins. The synthetic resin can also be a curable resin capable of forming a cross-linked structure through a cross-linking reaction. Curable resins can be classified according to the type of curing, such as ultraviolet-curable resins, electron beam-curable resins, ionizing radiation-curable resins, thermosetting resins, and moisture-curable resins. The thickness of the hard coating is not particularly limited, but is preferably 0.5 to 30 μm, more preferably 1 to 10 μm.

[0282] Other functional layers, such as a decorative layer and an antistatic layer, can be disposed between the hard coating layer and the adhesive layer. That is, the transfer sheet preferably comprises, in sequence, a hard coating layer, other functional layers, and an adhesive layer. Among these, a decorative layer is preferred as one of the other functional layers. The decorative layer is used to decorate the resin molded body. Examples of decorative layers include a printing layer and a metal film layer.

[0283] The printing layer preferably comprises an adhesive resin and a colorant. Examples of adhesive resins include polyvinyl resins, polyester resins, acrylic resins, polyvinyl acetal resins, and cellulose resins. Examples of colorants include pigments or dyes. Black pigments, metallic pigments, pearlescent pigments, and fluorescent pigments can be used as pigments.

[0284] The printed layer can be manufactured, for example, by printing a desired pattern using printing ink containing adhesive resin and colorant. The printed pattern can be appropriately determined by considering the design of the resin molded body, and examples include wood grain, stone grain, fabric grain, sand grain, circles, quadrilaterals, polygons, geometric stripes, text, all-over printing, etc.

[0285] Metal thin film layers can contain metals such as aluminum, silver, chromium, titanium oxide, and zinc oxide. These layers can be formed using known methods such as vacuum evaporation, sputtering, and plasma CVD. Embossing can also create fine, textured structures in the metal thin film layer, imparting a holographic effect.

[0286] A primer layer for improving adhesion can be disposed between the hard coating layer and other functional layers. That is, the transfer sheet may sequentially comprise a hard coating layer, a primer layer, other functional layers, and an adhesive layer. The primer layer preferably comprises an adhesive resin. Examples of adhesive resins include urethane resins, acrylic resins, (meth)acrylate-urethane copolymers, polyester resins, and butyraldehyde resins. The thickness of the primer layer is not particularly limited, but is preferably 0.1 to 10 μm.

[0287] The adhesive layer preferably comprises a heat-sealable adhesive. Examples of adhesives include vinyl chloride-vinyl acetate copolymer resin, acrylic resins, polyester resins, and cellulose-based materials such as CMC. The thickness of the adhesive layer is not particularly limited, but is preferably 0.5 to 10 μm.

[0288] A transfer functional sheet is integrally laminated onto the surface of a resin molded body via an adhesive layer to obtain a laminate. Then, a release sheet for the transfer functional sheet is peeled off from the laminate. Thus, only the transfer sheet of the transfer functional sheet is transferred, and a resin molded body with a functional layer such as a hard coating is obtained.

[0289] The surface of resin molded bodies often has complex three-dimensional shapes depending on the application. On the other hand, since the transfer functional sheet includes the release sheet of this invention, it has excellent elongation. Therefore, even when using resin molded bodies with complex three-dimensional shapes, the transfer functional sheet can fully conform to the three-dimensional shape of the resin molded body and adhere tightly to its surface. Furthermore, the release layer included in the release sheet of the transfer functional sheet has excellent release properties. Therefore, when peeling the release sheet from the laminate, the interface between the release layer and the hard coating can be easily separated, and the release sheet can be easily peeled from the laminate without damaging it.

[0290] As a method for transferring the functional sheet for transfer to a resin molded body, known heat transfer methods such as hot pressing, vacuum forming, compressed air forming, vacuum compressed air forming, and in-mold forming can be used. Among these, in-mold forming is preferred.

[0291] In in-mold molding, firstly, a transfer functional sheet is placed inside the mold of an injection molding machine, with its adhesive layer forming the inner side of the mold. Next, molten resin is injected into the mold and allowed to cool and solidify, resulting in a laminate of a resin molded body with the desired shape and the transfer functional sheet, which is integrally laminated to the surface of the resin molded body via the aforementioned adhesive layer. Then, a release sheet for the transfer functional sheet is peeled off from the laminate. Thus, only the transfer sheet of the transfer functional sheet is transferred, resulting in a resin molded body with a functional layer such as a hard coating.

[0292] Example

[0293] The present invention will be described in more detail below using examples, but the present invention is not limited thereto.

[0294] Synthesis of (meth)acrylic acid polyol (A)

[0295] (Synthetic Examples A1~A5)

[0296] 233 parts by mass of methyl isobutyl ketone (MIBK) were added to a reaction vessel as a solvent, and the temperature was raised to 80°C. Next, 4.0 parts by mass of azobis-2-methylbromobutyronitrile (trade name "ABN-E" manufactured by JNC Industries, Ltd.) as a polymerization catalyst were stirred and mixed with 100 parts by mass of a monomer composition containing methyl methacrylate (MMA), n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA), and α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane (number average molecular weight (Mn) 10000, trade name "Silaplane (registered trademark) FM-0725" manufactured by JNC Corporation) to prepare a monomer mixture. The monomer mixture was then added dropwise to the solvent over 3 hours, and the reaction was terminated after another 3 hours. This yielded a (meth)acrylic acid polyol solution (30% by mass solids) containing (meth)acrylic acid polyol (A).

[0297] It should be noted that the proportions of each monomer in the monomer composition were adjusted to obtain (meth)acrylic polyol (A) containing methyl methacrylate units, n-butyl acrylate units, 2-hydroxyethyl acrylate units, and α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane units in the amounts (mass %) shown in Table 1.

[0298] The resulting (meth)acrylic polyol (A) contains the structural unit (S1) with siloxane bonds shown in formula (1) above (in formula (1) above, R 1 and R 2(Methyl groups are represented independently). The content of structural units (S1) in (meth)acrylic acid polyol (A) is shown in Table 1.

[0299] Synthesis of (meth)acrylic acid polyol (B)

[0300] (Synthetic Examples B1~B6)

[0301] 233 parts by mass of methyl isobutyl ketone (MIBK) were added to a reaction vessel as a solvent, and the temperature was raised to 80°C. Next, 4.0 parts by mass of azobis-2-methylbromobutyronitrile (trade name "ABN-E" manufactured by JNC Industries, Ltd.) as a polymerization catalyst were stirred and mixed with 100 parts by mass of a monomer composition containing n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA), and α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane (number average molecular weight (Mn) 10000, trade name "Silaplane (registered trademark) FM-0725" manufactured by JNC Corporation) to prepare a monomer mixture. Then, the monomer mixture was added dropwise to the solvent over 3 hours, and the reaction was terminated after another 3 hours. This yielded a (meth)acrylic acid polyol solution (30% by mass solids) containing (meth)acrylic acid polyol (B).

[0302] It should be noted that the amount of each monomer in the monomer composition was adjusted so as to obtain (meth)acrylic polyol (B) containing n-butyl acrylate unit, 2-hydroxyethyl acrylate unit and α-butyl-ω-(3-methacryloyloxypropyl)polydimethylsiloxane unit respectively in the amounts (mass %) shown in Table 2.

[0303] The resulting (meth)acrylic polyol (B) contains the structural unit (S1) with siloxane bonds shown in formula (1) above (in formula (1) above, R 1 and R 2 (Methyl groups are represented independently). The content of structural unit (S1) in (meth)acrylic acid polyol (B) is shown in Table 2.

[0304] Synthesis of polyisocyanates (D) with structural unit (S2)

[0305] (Synthetic Example C)

[0306] In the reaction vessel, 150 parts by mass of methyl isobutyl ketone (MIBK) as solvent, 21.7 parts by mass of polyisocyanate (isocyanurate form of hexamethylene diisocyanate, manufactured by Asahi Kasei Corporation under the trade name "Duranate (registered trademark) TKA-100", NCO content: 21.6 parts by mass) without structural unit (S2) were added, along with 0.1 parts by mass of dibutyltin dilaurate as reaction catalyst.

[0307] Next, a polyol (R) having the structural unit (S2) was added dropwise to the reaction vessel over 1 hour. 14 and R 17 It is ethylene, R 15 and R 16 The polyol represented by formula (5) above, with m being an integer greater than or equal to 2 and having a number average molecular weight (Mn) of 5000, was manufactured by JNC Corporation under the trade name "Silaplane (registered trademark) FM-4421" (equivalent ratio (isocyanate group / hydroxyl group) 3.0). The carbamate reaction was then terminated after 3 hours. As a result, a polyisocyanate solution (solid content 40% by mass) containing polyisocyanate (D) with structural unit (S2) (NCO group content 5.0 wt%, structural unit (S2) content 77.3% by mass) was obtained.

[0308] It should be noted that the polyisocyanate (D) contains the structural unit (S2) with siloxane bonds shown in the above formula (4) (in the above formula (4), R 12 and R 13 Each methyl group is represented independently.

[0309] (Examples 1-10 and 13-19, Comparative Examples 1-4)

[0310] 100 parts by mass of polyol (P), 0.1 parts by mass of dibutyltin dilaurate as a curing catalyst, 4.6 parts by mass of methyl isobutyl ketone as a solvent, and 1.7 parts by mass of acetylacetone were fed into reaction vessel (I) and mixed to obtain the main agent (40% by mass of solid content). The polyol (P) contained, respectively, the (meth)acrylic acid polyol (A) obtained from synthesis examples A1 to A5, the (meth)acrylic acid polyol (B) obtained from synthesis examples B1 to B6, polycaprolactone triol (trade name "PLACCEL 303" manufactured by Daicel Co., Ltd., hydroxyl value 538 mg KOH / g), and polycaprolactone diol (trade name "PLACCEL 303" manufactured by Daicel Co., Ltd., hydroxyl value 538 mg KOH / g), as shown in Tables 3 to 5 (by mass %). 210”, hydroxyl value 113mgKOH / g), polytetramethylene ether glycol (trade name “PTMG-1000” manufactured by Mitsubishi Chemical Corporation) and polycarbonate glycol (trade name “UHC50-100” manufactured by UBE Corporation).

[0311] It should be noted that, for the (meth)acrylic polyols (A) obtained in synthesis examples A1 to A5, a (meth)acrylic polyol solution containing (meth)acrylic polyol (A) is supplied to the reaction vessel (I) in such a manner that the content (amount of solids) of each (meth)acrylic polyol (A) is as shown in Tables 3 to 5. Similarly, for the (meth)acrylic polyols (B) obtained in synthesis examples B1 to B6, a (meth)acrylic polyol solution containing (meth)acrylic polyol (B) is also supplied to the reaction vessel (I) in such a manner that the content (amount of solids) of each (meth)acrylic polyol (B) is as shown in Tables 3 to 5.

[0312] The content (mass %) of (meth)acrylic acid polyol (A), (meth)acrylic acid polyol (B), polycaprolactone triol and polycaprolactone diol in the polyol (P) of the main agent is expressed as a value not enclosed in parentheses in the "Main Agent" column of Tables 3-5.

[0313] The content of structural unit (S1) in (meth)acrylic polyol (A) is expressed as a value enclosed in parentheses in the "(meth)acrylic polyol (A)" column of Tables 3-5. Similarly, the content of structural unit (S1) in (meth)acrylic polyol (B) is expressed as a value enclosed in parentheses in the "(meth)acrylic polyol (B)" column of Tables 3-5.

[0314] Next, 100 parts by mass of polyisocyanate (I), 0.1 parts by mass of dibutyltin dilaurate as a curing catalyst, 120 parts by mass of methyl isobutyl ketone as a solvent, and 3.6 parts by mass of acetylacetone were fed into reaction vessel (II) and mixed to obtain a curing agent (40% by mass of solids). The polyisocyanate (I) contained, respectively, polyisocyanate (C) without structural unit (S2) (an adduct of diol without structural unit (S2) and hexamethylene diisocyanate, i.e., difunctional polyurethane diisocyanate, trade name "Duranate D-201" manufactured by Asahi Kasei Corporation, with 15.8 wt% NCO) and polyisocyanate (D) with structural unit (S2) obtained in synthesis example C, as shown in Tables 3-5. Thus, a two-component curable coating agent containing a main agent and a curing agent was obtained.

[0315] It should be noted that, for the polyisocyanate (D) with structural unit (S2) obtained in synthesis example C, the polyisocyanate (D) containing the polyisocyanate (D) with structural unit (S2) is supplied to the reaction vessel (II) in such a way that the polyisocyanate (D) with structural unit (S2) is in the amount (amount of solid components) shown in Tables 3 to 5.

[0316] In addition, the content (mass %) of polyisocyanate (C) without structural unit (S2) and polyisocyanate (D) with structural unit (S2) in the polyisocyanate (I) of the curing agent is expressed as a value not enclosed in parentheses in the "Curing Agent" column of Tables 3-5.

[0317] In addition, the content of the structural unit (S2) in the polyisocyanate (I) is expressed as a value enclosed in parentheses in the “Curing Agent” column of Tables 3-5.

[0318] Next, the curing agent was added to the main agent and mixed so that the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate (I) contained in the curing agent to the hydroxyl group of the polyol (P) contained in the main agent was as shown in Tables 3-5. Then, a two-component curable coating agent was immediately applied to one side of the support layer (polybutylene terephthalate film, 50 μm thick, manufactured by Okura Kogyo Co., Ltd. under the trade name "ESRM"), and heated at 120°C for 5 minutes to remove the solvent and heat-cur it, forming a release layer (20 μm thick) on one side of the support layer. Thus, a release sheet having a support layer and a release layer integrally laminated on one side of the support layer was obtained.

[0319] (Examples 11 and 12)

[0320] In the preparation of the main agent, silica particles (volume average particle size 10 μm) or urethane resin particles (volume average particle size 10 μm) were further supplied to the reaction vessel (I). Otherwise, the main agent, curing agent and release sheet were manufactured according to the same steps as in Example 5.

[0321] It should be noted that the content ratio of silica particles or urethane resin particles in the two-component curing coating agent relative to the total amount of polyol (P) in the main agent, polyisocyanate (I) in the curing agent, and particles per 100 parts by mass is set as shown in Table 3 or 4.

[0322] [evaluate]

[0323] For the release sheets obtained in the examples and comparative examples, elongation, release properties, exudation resistance, and particle shedding resistance were evaluated according to the following steps. The results are shown in Tables 3-5.

[0324] (Elongation)

[0325] According to JIS K7127 (Plastics - Test methods for tensile properties), the release sheet was cut into test piece type 2 shape, and the elongation (%) was measured using a tensile testing machine (Shimadzu Corporation, trade name "Autograph AGS-X") at a tensile speed of 50 mm / min. Then, the elongation was evaluated according to the following evaluation criteria.

[0326] [Evaluation Criteria]

[0327] A: The elongation rate is over 200%.

[0328] B: Elongation rate is 150% or more but less than 200%.

[0329] C: Elongation rate is 50% or more but less than 150%.

[0330] F: Elongation less than 50%.

[0331] (Mold release properties)

[0332] An aluminum foil strip (manufactured by Nitto Denko Corporation, trade name "Nitohoil AT-50") with an aluminum foil and an adhesive layer formed by an acrylic adhesive was prepared. The aluminum foil strip was adhered to the surface of the release layer of the release sheet in such a way that the release layer and the adhesive layer were in contact. After standing at room temperature for 24 hours in this state, an evaluation sheet was obtained. Then, the aluminum foil strip was peeled from the evaluation sheet, and the peel strength was measured using a peel testing machine (manufactured by TESTER SANGYO Corporation, trade name "TE-1003"). It should be noted that the peel angle was set to 180 degrees, and the peel speed was set to 300 mm / min. The peel strength was evaluated according to the following criteria.

[0333] [Evaluation Criteria]

[0334] A: Peel strength is less than 1.5N / 2.5cm.

[0335] B: Peel strength is above 1.5N / 2.5cm and less than 2.5N / 2.5cm.

[0336] C: Peel strength is above 2.5N / 2.5cm and less than 3.5N / 2.5cm.

[0337] F: Peel strength is above 3.5N / 2.5cm.

[0338] (Resistance to leaching)

[0339] A PET film (50μm, manufactured by Toyobo Co., Ltd., trade name COSMOSHINEA4160) is overlapped on the release layer of the release sheet, and then pressed using a hot press at 175°C and a pressure of 80 kg / cm². 2 It was hot-pressed for 5 minutes under the specified conditions.

[0340] Then, the PET film was peeled off from the release layer. A 2μL drop of distilled water was placed on the surface of the PET film that had been in contact with the release layer. The contact angle A1 (°) between the PET film surface and the distilled water droplet was measured using an automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., trade name "DMs-601"). It should be noted that, as... Figure 1 As shown, the "contact angle" refers to the angle θ formed by the tangent L of the distilled water droplet at the endpoint P of the interface between the distilled water droplet W and the PET film surface S, which includes the distilled water droplet W.

[0341] Then, for the PET film surface before hot pressing, a drop of 2 μL of distilled water was added, as described above, and the contact angle A0 (°) between the PET film surface and the distilled water droplet was measured. Then, the difference X in the contact angle was calculated based on the following formula, and the evaluation was carried out according to the following evaluation criteria.

[0342] The difference in contact angle X (°) = [Contact angle A1 (°)] - [Contact angle A0 (°)]

[0343] [Evaluation Criteria]

[0344] A: The difference in contact angle X is less than 3°.

[0345] B: The difference in contact angle X is greater than 3° and less than 6°.

[0346] C: The difference in contact angle X is greater than 6° and less than 11°.

[0347] F: The difference in contact angle X is 11° or more.

[0348] It should be noted that a larger difference in contact angle X indicates higher hydrophobicity of the PET film surface after hot pressing. It can be considered that through hot pressing, components with siloxane bonds in the release layer (e.g., (meth)acrylic acid polyol (B), polyisocyanate (D) with structural unit (S2), etc.) diffuse to the surface of the release layer and migrate to the PET film, thus increasing the hydrophobicity of the PET film surface. Therefore, a smaller difference in contact angle X indicates lower hydrophobicity of the PET film surface, reducing the diffusion of components with siloxane bonds and resulting in superior leaching resistance.

[0349] (Particle resistance to shedding)

[0350] After placing the release sheet between the upper and lower molds of the semiconductor sealing compression molding apparatus (FFT-1030), vacuum suction is used to seal the release sheet against the parting face of the lower mold. A semiconductor chip, fixed to a substrate, is then placed on the parting face of the upper mold. Next, sealing resin is added to the cavity of the lower mold, where the release sheet is sealed against the parting face, and the mold temperature is heated to 175°C to melt the sealing resin. Then, the upper and lower molds are closed, and air is extracted from the vacuum suction holes at the edge of the cavity using a vacuum pump. Compression molding is then performed under the following sealing conditions to seal the semiconductor element fixed to the substrate with sealing resin, resulting in a semiconductor package. Finally, the semiconductor package is demolded from the mold and the release sheet and removed.

[0351] <Sealing conditions>

[0352] Mold temperature: 175℃

[0353] Cavity dimensions: 220mm × 54mm

[0354] Cavity depth: 0.8mm

[0355] Sealing resin: Thermosetting epoxy resin

[0356] Molding time: 120 seconds

[0357] Molding pressure: 80 kg / cm 2

[0358] The surface of the sealed resin portion of the removed semiconductor package that came into contact with the release liner was used as the measurement surface. This measurement surface was observed using a scanning electron microscope (SEM) at 100x magnification, and the number of particles attached to it was counted. For any 10 locations on the measurement surface, the number of attached particles was counted using the same procedure, and the arithmetic mean was taken as the "average particle count." The counts were then evaluated according to the following criteria.

[0359] [Evaluation Criteria]

[0360] A: The average number of attached particles is less than 10.

[0361] B: The average number of attached particles is more than 10 and less than 100.

[0362] F: The average number of attached particles is more than 100.

[0363] It should be noted that the particle shedding resistance test was only performed on the release sheets of Examples 11 and 12, where the release layer contained silica particles or urethane resin particles. The particles adhering to the test surface of the semiconductor package are silica particles or urethane resin particles that have detached from the release layer of the release sheet.

[0364]

[0365]

[0366]

[0367]

[0368]

[0369] Industrial applicability

[0370] The two-component curable coating agent for release sheets according to the present invention can form a release layer with excellent release properties and elongation. Release sheets having such a release layer are suitable for use in the manufacture of resin molded articles, such as semiconductor packages. According to the release sheet, resin molded articles such as semiconductor packages can be easily removed from the inside of the mold, and the occurrence of appearance defects in resin molded articles due to wrinkles or damage of the release sheet can be reduced.

[0371] (Cross-reference to related applications)

[0372] This application claims priority based on Japanese Patent Application No. 2023-191499, filed on November 9, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A two-component curing coating agent for release sheets, comprising: a base agent containing a polyol (P) and a curing agent containing a polyisocyanate (I), The polyol (P) comprises: The content of the structural unit (S1) with siloxane bonds shown in formula (1) below is more than 0% by mass and less than 12% by mass of (meth)acrylic acid polyol (A), and The content of the structural unit (S1) with siloxane bonds shown in formula (1) below is 12% by mass or more and 30% by mass or less (meth)acrylic acid polyol (B). In equation (1), R 1 and R 2 Each symbol represents a hydrogen atom or a monovalent hydrocarbon group independently, with * indicating a bonding site.

2. The two-component curable coating agent for release sheets according to claim 1, wherein, The polyol (P) further comprises at least one polyol selected from polyester polyols, polyether polyols, polycarbonate polyols and alkyl polyols.

3. The two-component curable coating agent for release sheets according to claim 1, wherein, The polyisocyanate (I) contains 0.5% by mass and 40% by mass of the following structural unit (S2) with siloxane bonds as shown in formula (4). In equation (4), R 12 and R 13 Each symbol represents a hydrogen atom or a monovalent hydrocarbon group independently, with * indicating a bonding site.

4. The two-component curing coating agent for release sheets according to claim 1, wherein, At least one of the main agent and the curing agent further comprises particles.

5. The two-component curable coating agent for release sheets according to claim 4, wherein, The particles contain urethane resin particles.

6. A release sheet having a support layer and a release layer, The release layer is integrally stacked on one side of the support layer and is a cured film of the two-component curable coating agent for the release sheet as described in claim 1.

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