Urethane composition, cured product, impact-resistant adhesive, and power semiconductor sealing agent

Abstract

The purpose of the present invention is to provide a urethane composition capable of forming a cured product having sufficient impact resistance and excellent tensile strength and elongation. The urethane composition according to the present disclosure is characterized by containing an ester-based polyol containing a structural moiety derived from an alicyclic diol compound and a polyisocyanate, and is not confirmed to have a crystal melting peak by DSC analysis. In addition, it is preferable that the polyisocyanate be a non-aromatic isocyanate, and it is preferable that the polyisocyanate include a bifunctional isocyanate and a trifunctional isocyanate.

Description

Technical Field

[0001] This disclosure relates to urethane compositions, cured products, impact-resistant adhesives, and power semiconductor encapsulants. Furthermore, this application claims priority to Japanese Patent Application No. 2023-138986, filed on August 29, 2023, the contents of which are incorporated herein by reference. Background Technology

[0002] As a method for dissipating (heat dissipation) heat emitted by electronic components to the outside, a thermally conductive resin that can conform to the shape of the heat-generating element and has flexibility is used. As a thermally conductive resin with excellent heat dissipation and adhesion to the heat-generating element, a urethane-based composition containing specific ester polyols, polyisocyanates, and fillers is known (e.g., Patent Document 1).

[0003] Furthermore, it is known that when electronic components are used in large devices such as automobiles, excellent shock resistance is required to withstand external stimuli such as vibration.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-533467 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the invention of the urethane-based composition described in Patent Document 1 has the following problems: the ester-based polyols and polyisocyanates used are prone to crystallization, and become too hard when the product is cured, thus the impact resistance is easily reduced.

[0009] In addition, to solve the above problems, it is necessary to use a large amount of polyisocyanates with specific structures, but it is also known that the strength and elongation of the resin tend to deteriorate in this case.

[0010] Therefore, the object of this disclosure is to provide a urethane composition capable of forming a cured product with sufficient impact resistance and excellent tensile strength and elongation.

[0011] Solution for solving the problem

[0012] The discloser has made extensive efforts to solve the above-mentioned problems and has discovered that a cured product with sufficient impact resistance and excellent tensile strength and elongation can be formed by a urethane composition comprising an ester polyol and a polyisocyanate, wherein the ester polyol contains a specific structural part, and no crystal melting peak was identified in the urethane composition by DSC analysis. This disclosure relates to a technical solution based on these insights.

[0013] That is, this disclosure provides a carbamate composition comprising an ester polyol and a polyisocyanate, wherein the ester polyol comprises a structural part derived from an alicyclic diol compound, and the carbamate composition did not show a crystal melting peak by DSC analysis.

[0014] No crystal melting peak was detected in the above-mentioned urethane composition by DSC analysis, thus it is not prone to over-curing due to crystallization and can exhibit impact resistance. In addition, by including a structural part derived from an alicyclic diol compound in the above-mentioned ester polyol, the tensile strength and elongation of the cured product are excellent.

[0015] Preferably, the polyisocyanate is a non-aromatic polyisocyanate. By using a non-aromatic isocyanate, processing becomes easier.

[0016] Preferably, the polyisocyanate comprises difunctional and trifunctional isocyanates. With the above-described structure, crystallization of the urethane composition can be suppressed, and the cured product readily exhibits impact resistance.

[0017] Preferably, the amount of trifunctional isocyanate in the above-mentioned polyisocyanate is less than 45%. With the above-mentioned structure, the tensile strength and elongation of the cured product can be easily improved.

[0018] Preferably, the polyisocyanate comprises hexamethylene diisocyanate and hexamethylene diisocyanate trimer.

[0019] Preferably, the ester-based polyol is a polycaprolactone polyol with a number average molecular weight of 400-800. By having the above-described structure, the crystallinity of the urethane composition can be reduced, making it easier to achieve the impact resistance of the cured product.

[0020] Preferably, the compound contains 1,4-cyclohexanediethanol as the aforementioned alicyclic diol compound.

[0021] Preferably, the above-mentioned carbamate composition is a two-component type.

[0022] Furthermore, this disclosure provides a cured product, which is a cured product of the above-mentioned carbamate composition.

[0023] In addition, this disclosure provides an impact-resistant adhesive comprising the above-mentioned cured product.

[0024] In addition, this disclosure provides a power semiconductor encapsulant comprising the above-mentioned cured material.

[0025] Invention Effects

[0026] The urethane compositions disclosed herein can form cured products with excellent impact resistance, tensile strength, and elongation. Detailed Implementation

[0027] [Carbamate Composition]

[0028] A carbamate composition according to one embodiment of the present disclosure (hereinafter, sometimes referred to as "the carbamate composition of the present disclosure") comprises an ester polyol and a polyisocyanate, wherein the ester polyol comprises a structural portion derived from an alicyclic diol compound, and the carbamate composition does not show a crystal melting peak as confirmed by DSC analysis.

[0029] The urethane composition disclosed herein did not show a crystal melting peak upon DSC analysis, thus preventing over-curing due to crystallization and enhancing its impact resistance. Furthermore, by including a structural portion derived from an alicyclic diol compound in the aforementioned ester-based polyol, a cured product with excellent tensile strength and elongation can be produced.

[0030] The viscosity of the urethane composition disclosed herein at 25°C is preferably 20,000 mPa·s or less, more preferably 10,000 mPa·s or less, even more preferably 1,000 mPa·s or less, particularly preferably 500 mPa·s or less, and may also be 300 mPa·s or less. With a viscosity of 20,000 mPa·s or less, a substance exhibiting sufficient fluidity and excellent workability in a liquid state can be prepared. Furthermore, as a lower limit, there is no particular limitation, but it is preferably 10 mPa·s or more, more preferably 50 mPa·s or more. It should be noted that the above viscosity was measured using an E-type viscometer, and when the urethane composition contains filler, it was measured using a rheometer.

[0031] (Ester-based polyols)

[0032] The urethane composition disclosed herein comprises an ester-based polyol, wherein the ester-based polyol contains a structural portion derived from an alicyclic diol compound. Because the ester-based polyol in the urethane composition contains a structural portion derived from an alicyclic diol compound, it is less prone to crystallization with polyisocyanates, thereby reducing the amount of polyisocyanate incorporated and resulting in excellent tensile strength and elongation of the cured product. It should be noted that, in this disclosure, "ester-based polyol" refers to a compound whose molecule contains two or more monomer units polymerized with ester bonds and has two or more hydroxyl groups. The ester-based polyol in the urethane composition of this disclosure may be used in only one form or in two or more forms.

[0033] Examples of the aforementioned ester-based polyols include carboxylic acid polyols, which are condensation polymers of polyols and polycarboxylic acids, and lactone-based polyols, which are ring-opening polymers of cyclic esters (lactones). Among these, lactone-based polyols derived from lactones using the aforementioned alicyclic diol compound as an initiator are preferred. More specifically, the aforementioned ester-based polyols are preferably obtained by ring-opening polymerization of lactones using the aforementioned alicyclic diol compound as an initiator.

[0034] Examples of the aforementioned alicyclic diol compounds include: cyclohexanediols such as 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, and 2-methyl-1,4-cyclohexanediol; cyclohexanediols such as 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, and 1,4-cyclohexanediethanol; norbornanediols such as 2,3-norbornanediethanol and 2,5-norbornanediethanol; tricyclodecanediethanol; pentacyclopentadecanedimethanol; 1,3-adamantanediol; 2,2-adamantanediol; decahydronaphthalenediethanol; 2,2,4,4-tetramethyl-1,3-cyclobutanediol; and isosorbide, with cyclohexanediols being preferred, and 1,4-cyclohexanediol being particularly preferred. It should be noted that only one or more of the aforementioned alicyclic diol compounds may be used.

[0035] Specifically, examples of the aforementioned lactones include: β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, γ-valerolactone, γ-caprolactone, γ-octyllactone, γ-laurolactone, heptanolactone, dodecyllactone, stearyllactone, alkyl-ε-caprolactone [e.g., monomethyl-ε-caprolactone (α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ-methyl-ε-caprolactone, etc.), dimethyl-ε-caprolactone (β,δ-dimethyl-ε-caprolactone, etc.), trimethyl-ε-caprolactone (3,3,5-trimethyl-ε-caprolactone, etc.) and other methyl-ε-caprolactones, etc.], with ε-caprolactone being the most preferred. That is, the lactone-based polyols disclosed herein are preferably polycaprolactone polyols. It should be noted that, as the above-mentioned lactones, only one type may be used, or two or more types may be used.

[0036] The number-average molecular weight of the above-mentioned ester-based polyols is not particularly limited, but is preferably 400 to 800, more preferably 450 to 750, and even more preferably 500 to 700. By keeping the number-average molecular weight of the above-mentioned ester-based polyols within the above range, excellent operability can be achieved.

[0037] It should be noted that the above-mentioned ester-based polyols are preferably liquid at any temperature within room temperature. In this disclosure, "room temperature" refers to 20–30°C.

[0038] (Polyisocyanates)

[0039] The urethane compositions disclosed herein contain polyisocyanates. The aforementioned polyisocyanates function as curing agents in the urethane compositions disclosed herein. In the urethane compositions disclosed herein, only one type of polyisocyanate may be used, or two or more types may be used. It should be noted that, in this disclosure, "polyisocyanate" refers to a compound having two or more isocyanate groups (i.e., difunctional or higher).

[0040] From an operational point of view, the aforementioned polyisocyanate is preferably a non-aromatic polyisocyanate, more preferably an aliphatic polyisocyanate or an alicyclic polyisocyanate, and particularly preferably an aliphatic polyisocyanate.

[0041] Furthermore, regarding the aforementioned polyisocyanates, from the viewpoint of reducing the crystallinity of the urethane composition, it is preferable to include isocyanates with trifunctionality or higher. From the viewpoint of maximizing the tensile strength and elongation of the cured product, it is more preferable to include difunctional isocyanates and isocyanates with trifunctionality or higher. Particularly preferred is the inclusion of difunctional isocyanates and trifunctional isocyanates.

[0042] Specifically, examples of the aforementioned difunctional isocyanates include: tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, decamethylene diisocyanate, and other aliphatic polyisocyanates; 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and other alicyclic polyisocyanates.

[0043] As an isocyanate with three or more functions, oligomers of compounds that are exemplified as difunctional isocyanates can be listed, and trimers of the difunctional isocyanates are particularly preferred.

[0044] The carbamate composition disclosed herein preferably contains hexamethylene diisocyanate and hexamethylene diisocyanate trimer.

[0045] Furthermore, when the aforementioned polyisocyanate contains a trifunctional isocyanate, its amount is preferably less than 45% by mass of the total polyisocyanate (100% by mass), more preferably 40% by mass or less, and even more preferably 35% by mass or less. By keeping the amount of trifunctional isocyanate less than 45% by mass, the cured product readily exhibits sufficient tensile strength and elongation. Additionally, since trifunctional isocyanates are typically expensive, this also reduces costs. As a lower limit, it is preferably 5% by mass or more, more preferably 10% by mass or more. With an amount of trifunctional isocyanate of 5% by mass or more, crystallization of the urethane composition is easily suppressed.

[0046] In the urethane compositions disclosed herein, it is preferred that the ratio of the molar number of isocyanate groups in the polyisocyanate to the molar number of hydroxyl groups in the ester polyol [NCO / hydroxyl] is preferably in the range of 0.8 to 1.5, more preferably 0.85 to 1.4, and even more preferably 0.9 to 1.3. That is, the ratio of the molar number of structural portions derived from isocyanate groups to the molar number of structural portions derived from the ester polyol other than those forming ester bonds is preferably within the above range in the urethane compositions disclosed herein.

[0047] To facilitate the reaction between the aforementioned ester-based polyols and the aforementioned polyisocyanates, the carbamate compositions disclosed herein preferably include a catalyst. Known or conventional catalysts can be used, including amine-based catalysts, imidazole-based catalysts, and metal-based catalysts. Only one type of catalyst may be used, or two or more may be used.

[0048] Examples of amine catalysts mentioned above include: triethylenediamine, 2-methyltriethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N”,N”-pentamethyldiethylenetriamine, N,N,N',N”,N”-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N',N”,N”-pentamethyldipropylenetriamine, N,N,N',N’-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl) ether, etc.

[0049] Examples of imidazole-based catalysts include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, and 1-dimethylaminopropylimidazole.

[0050] Examples of metal-based catalysts include: stannous diacetate, stannous dioctate, stannous dioleate, stannous dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate, and other organotin catalysts.

[0051] The amount of the catalyst used is preferably 0.001 to 0.05 parts by mass, more preferably 0.005 to 0.03 parts by mass, relative to the total amount of resin components in the urethane composition (100 parts by mass).

[0052] Furthermore, in order to achieve sufficient heat dissipation when the product is cured, the urethane composition disclosed herein may contain fillers. One type of filler may be used, or two or more may be used.

[0053] As the aforementioned filler, known or conventional fillers can be used, such as metal fillers, carbon fillers, and metal oxide fillers. Examples of metal fillers include those made of gold, silver, copper, nickel, palladium, tin, aluminum, or alloys thereof. Metal fillers can be formed from a single metal, or, as in a core-shell structure, from two or more metals.

[0054] Examples of the shapes of the fillers mentioned above include spherical, irregular, sheet-like (flat), needle-like, fibrous, and rod-like shapes. Furthermore, the average particle size (median particle size) is preferably 1 nm to 100 μm, more preferably 10 nm to 50 μm, even more preferably 30 nm to 35 μm, and particularly preferably 50 nm to 10 μm.

[0055] When the filler described above is included, the amount of the compound relative to the total amount (100% by mass) of the urethane composition is preferably 50 to 95% by mass, more preferably 60 to 90% by mass. Within this range, heat dissipation is easily achieved.

[0056] (Other ingredients)

[0057] The urethane composition disclosed herein may contain other components besides the aforementioned ester polyols, polyisocyanates, catalysts, and fillers. Examples of such other components include: polyols other than the aforementioned ester polyols, light stabilizers, ultraviolet absorbers, antioxidants, solvents, flame retardants, pigments, antimicrobial agents, antistatic agents, processing aids, viscosity improvers, etc. Relative to 100% by mass of the total urethane composition of this disclosure, the aforementioned other compounds are preferably present in an amount of 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, and particularly preferably 0% by mass.

[0058] Furthermore, in the total amount (100% by mass) of polyols contained in the carbamate composition disclosed herein, the amount of the aforementioned ester polyols is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0059] The urethane composition disclosed herein can be prepared by mixing the above-mentioned components using known or conventional methods. In particular, the urethane composition disclosed herein is preferably a two-component urethane composition prepared by mixing the above-mentioned ester-based polyol as the main agent and the above-mentioned polyisocyanate as the curing agent.

[0060] (cured material)

[0061] The urethane composition of this disclosure can be cured by known or conventional methods, thereby producing a cured urethane composition. In particular, when the urethane composition of this disclosure is a two-component urethane composition, it can be cured by heating or at room temperature. When curing by heating, the preferred heating temperature is 25 to 150°C. Furthermore, the curing time can be 0.5 to 20 hours.

[0062] The A hardness of the cured material, measured when it is formed to a thickness of 6 mm or more, is preferably 50 to 69, more preferably 55 to 68, and even more preferably 60 to 67. With an A hardness of 69 or less, the cured material readily exhibits impact resistance. Furthermore, with an A hardness of 50 or more, the cured material is less likely to be damaged due to excessive softness.

[0063] For the aforementioned cured material, using a No. 3 dumbbell, the tensile strength at fracture, measured under conditions of a tensile speed of 500 mm / min and a chuck distance of 60 mm, is preferably 18 MPa or more, more preferably 20 MPa or more, and even more preferably 22 MPa or more. A tensile strength of 18 MPa or more provides sufficient strength. Furthermore, there is no particular upper limit, but 50 MPa or less is preferred.

[0064] Furthermore, the elongation at break, measured under the same conditions as the tensile strength described above, is preferably 300% or more, more preferably 350% or more, and even more preferably 400% or more. An elongation of 300% or more ensures sufficient elongation of the cured material. Furthermore, there is no particular upper limit, but 600% or less is preferred.

[0065] Regarding the aforementioned cured material, according to JIS K 6850, for test pieces made by bonding Al substrates together, the shear bond strength measured at a test speed of 5 mm / min and a chuck distance of 112.5 mm is preferably 3.6 MPa or more, more preferably 3.8 MPa or more, and even more preferably 4.0 MPa or more. Furthermore, as an upper limit, there is no particular limitation, but 10 MPa or less is preferred.

[0066] Furthermore, regarding the aforementioned cured material, according to JIS K 6850, for test pieces made by bonding Al and PET substrates, the shear bond strength measured at a test speed of 5 mm / min and a chuck distance of 112.5 mm is preferably 2.0 MPa or more, more preferably 2.5 MPa or more. Moreover, as an upper limit, there is no particular limitation, but 10 MPa or less is preferred.

[0067] The cured product was cured under the conditions described in the following examples. When heated using a differential scanning calorimeter at a controlled temperature of 10°C / min, no crystal melting peak was detected. Because no crystal melting peak was detected, over-curing during the preparation of the cured product was suppressed, thus enhancing its impact resistance.

[0068] The cured material exhibits excellent impact resistance, tensile strength, and elongation, making it suitable as an impact-resistant adhesive, particularly for use in large, high-vibration applications such as automobiles and aircraft. Furthermore, its heat dissipation properties make it suitable as a packaging agent for high-output, high-heat-generating power semiconductors.

[0069] The various solutions disclosed in this specification can also be combined with any other features disclosed in this specification. Furthermore, the various configurations and combinations of configurations in each embodiment are merely examples, and appropriate additions, omissions, and other modifications to the configuration can be made without departing from the spirit of this disclosure. This disclosure is not limited to the embodiments, but only to the claims.

[0070] Example

[0071] The following describes one embodiment of the present disclosure in more detail based on an example.

[0072] Example 1

[0073] 128.21 g of 1,4-cyclohexanediethanol-modified polycaprolactone diol (Mw: 530), 36.19 g of HDI (trade name "HDI", manufactured by Tosoh Co., Ltd.), 15.61 g of HDI trimer (trade name "Duranate TKA-100", manufactured by Asahi Kasei Co., Ltd.) (HDI trimer content 30% by mass), and 0.018 g of dibutyltin dilaurate (DBTDL) were weighed into a mixing cup. Vacuum degassing and stirring were performed for 60 seconds using a vacuum degassing mixer (trade name "Vacuum Degassing Rentaro", manufactured by THINKY Co., Ltd.) to prepare the urethane composition of Example 1. Furthermore, the above urethane composition was injection molded in an injection mold made by clamping a silicone spacer between glass plates. After injection molding, it was cured in a GIL oven set to 30°C for at least 16 hours. After curing, it was demolded from the glass mold and cured for at least two days to obtain the cured product. It should be noted that the thickness of the cured material is 2mm.

[0074] Example 2

[0075] 124.45 g of 1,4-cyclohexanediethanol-modified polycaprolactone diol (Mw: 530), 30.76 g of HDI (trade name "HDI", manufactured by Tosoh Corporation), 24.79 g of HDI trimer (trade name "Duranate TKA-100", manufactured by Asahi Kasei Corporation) (HDI trimer content 45% by mass), and 0.018 g of dibutyltin dilaurate (DBTDL) were weighed into a stirring cup. Vacuum degassing and stirring were performed for 60 seconds using a vacuum degassing mixer (trade name "Vacuum Degassing Rentaro", manufactured by THINKY Corporation) to prepare the urethane composition of Example 2. Furthermore, the cured product of Example 2 was prepared using the same method as in Example 1.

[0076] Comparative Example 1

[0077] 113.75 g of 1,4-BG modified polycaprolactone diol (Mw: approx. 400), 36.69 g of HDI (trade name "HDI", manufactured by Tosoh Co., Ltd.), 29.57 g of HDI trimer (trade name "Duranate TKA-100", manufactured by Asahi Kasei Co., Ltd.) (HDI trimer content 45% by mass), and 0.018 g of dibutyltin dilaurate (DBTDL) were weighed into a stirring cup. Vacuum degassing and stirring were performed for 60 seconds using a vacuum degassing mixer (trade name "Vacuum Degassing Rentaro", manufactured by THINKY Co., Ltd.) to prepare the urethane composition of Comparative Example 1. Furthermore, the cured product of Comparative Example 1 was prepared by the same method as in Example 1.

[0078] Comparative Example 2

[0079] 117.87 g of 1,4-BG modified polycaprolactone diol (Mw: approx. 400), 43.41 g of HDI (trade name "HDI", manufactured by Tosoh Co., Ltd.), 18.72 g of HDI trimer (trade name "Duranate TKA-100", manufactured by Asahi Kasei Co., Ltd.) (HDI trimer content 30% by mass), and 0.018 g of dibutyltin dilaurate (DBTDL) were weighed into a stirring cup. Vacuum degassing and stirring were performed for 60 seconds using a vacuum degassing mixer (trade name "Vacuum Degassing Rentaro", manufactured by THINKY Co., Ltd.) to prepare the urethane composition of Comparative Example 2. Furthermore, the cured product of Comparative Example 2 was prepared by the same method as in Example 1.

[0080] [evaluate]

[0081] The urethane compositions and their cured products obtained in the Examples and Comparative Examples were evaluated as follows, and the results are recorded in Table 1.

[0082] (1) Viscosity

[0083] The viscosity of the carbamate compositions of the examples and comparative examples at 25°C was determined using an E-type viscometer.

[0084] (2) A Hardness

[0085] The A hardness was measured using a hardness tester (trade name "GS-610", manufactured by TECLOCK Co., Ltd.) when the cured products of the examples and comparative examples were overlapped three times to form a thickness of 6 mm or more.

[0086] (3) Tensile strength and elongation

[0087] Dumbbell test pieces No. 3 were cut from the cured products of the Examples and Comparative Examples using a dumbbell cutter. Tensile tests were performed using a tensile testing machine (trade name "RTC-1350A", manufactured by A&D Corporation) at a tensile speed of 500 mm / min and a chuck distance of 60 mm to determine the tensile strength and elongation at fracture of the cured products.

[0088] (4) Shear adhesion force

[0089] The urethane compositions of the examples and comparative examples were coated and spread onto Al or PET substrates with test piece dimensions specified in JIS K 6850. Al substrates were then bonded together or bonded to PET substrates. Test pieces were obtained by curing in a GIL oven at 30°C for at least 16 hours. The tensile shear bond strength of the obtained test pieces was measured using a tensile testing machine (trade name "RTC-1350A", manufactured by A&D Corporation) at a test speed of 5 mm / min and a chuck distance of 112.5 mm.

[0090] (5) Presence or absence of crystal melting peak

[0091] Using a differential scanning calorimeter (trade name "DSC Q-2000", manufactured by TA Instruments), the cured products of the examples and comparative examples were heated at a temperature control of 10°C / min, and the presence or absence of crystal melting peaks in the crystal composition was determined.

[0092] [Table 1]

[0093]

[0094] Regarding the urethane compositions of the examples, since the ester-based polyols contain structural portions derived from alicyclic diols, the amount of polyisocyanate added can be suppressed, resulting in excellent tensile strength and elongation of the cured product. Furthermore, since no crystal melting peak was observed by DSC analysis, impact resistance was confirmed. On the other hand, it was revealed that when the ester-based polyols do not contain structural portions derived from alicyclic diols, a large amount of polyisocyanate is required to suppress hardness, resulting in poor tensile strength and elongation of the cured product (Comparative Example 1). Furthermore, it was revealed that when a crystal melting peak is observed, hardness increases, resulting in poor impact resistance (Comparative Example 2).

[0095] The following describes variations of this disclosure.

[0096] [Appendix 1]

[0097] A carbamate composition comprising an ester polyol and a polyisocyanate, wherein the ester polyol comprises a structural portion derived from an alicyclic diol compound, and the carbamate composition did not show a crystal melting peak as confirmed by DSC analysis.

[0098] [Appendix 2]

[0099] According to Appendix 1, the urethane composition has a viscosity of less than 20,000 mPa·s at 25°C.

[0100] [Appendix 3]

[0101] According to Appendix 1 or 2, the urethane composition has a viscosity of 10 mPa·s or higher at 25°C.

[0102] [Appendix 4]

[0103] The carbamate composition according to any one of Appendices 1 to 3, wherein the polyisocyanate is a non-aromatic polyisocyanate.

[0104] [Appendix 5]

[0105] The carbamate composition according to any one of Appendices 1 to 4, wherein the polyisocyanate comprises a difunctional isocyanate and a trifunctional isocyanate.

[0106] [Appendix 6]

[0107] According to the carbamate composition described in Appendix 5, the amount of trifunctional isocyanate in the polyisocyanate is less than 45% by mass.

[0108] [Appendix 7]

[0109] The urethane composition according to any one of Appendices 1 to 6, wherein the polyisocyanate comprises hexamethylene diisocyanate and hexamethylene diisocyanate trimer.

[0110] [Appendix 8]

[0111] The urethane composition according to any one of Appendices 1 to 7, wherein the ester polyol is a polycaprolactone polyol with a number average molecular weight of 400 to 800.

[0112] [Appendix 9]

[0113] The carbamate composition according to any one of Appendices 1 to 8, wherein the carbamate composition comprises 1,4-cyclohexanediethanol as the alicyclic diol compound.

[0114] [Postscript 10]

[0115] The carbamate composition according to any one of Appendices 1 to 9, wherein the carbamate composition contains a catalyst.

[0116] [Postscript 11]

[0117] The urethane composition according to any one of Appendices 1 to 10, wherein the urethane composition comprises a filler.

[0118] [Postscript 12]

[0119] The carbamate composition according to any one of Appendices 1 to 11, wherein the carbamate composition is a two-component type.

[0120] [Postscript 13]

[0121] A cured product, which is a cured product of the urethane composition according to any one of Appendices 1 to 12.

[0122] [Postscript 14]

[0123] According to Appendix 13, the cured material has an A hardness of 50 to 69 when it is formed in a state with a thickness of 6 mm or more.

[0124] [Postscript 15]

[0125] According to Appendix 13 or 14, the cured material, using a No. 3 dumbbell, has a tensile strength at break of 18 MPa or higher, measured at a tensile speed of 500 mm / min and a chuck distance of 60 mm.

[0126] [Postscript 16]

[0127] The cured product according to any one of Annexes 13 to 15, wherein the elongation at break, measured using a No. 3 dumbbell at a tensile speed of 500 mm / min and a chuck distance of 60 mm, is 300% or more.

[0128] [Postscript 17]

[0129] According to any one of Annexes 13 to 16, the cured product, in accordance with JIS K 6850, has a shear bond strength of 3.6 MPa or more for a test piece made by bonding Al substrates together, measured at a test speed of 5 mm / min and a chuck distance of 112.5 mm.

[0130] [Postscript 18]

[0131] According to any one of Annexes 13 to 17, the cured product, in accordance with JIS K 6850, has a shear bond strength of 2.0 MPa or more for a test piece made by bonding an Al substrate to a PET substrate, measured at a test speed of 5 mm / min and a chuck distance of 112.5 mm.

[0132] [Postscript 19]

[0133] An impact-resistant adhesive comprising a cured product according to any one of Appendices 13 to 18.

[0134] [Postscript 20]

[0135] A power semiconductor encapsulant comprising a cured product according to any one of Appendices 13 to 18.

Claims

1. A carbamate composition comprising an ester polyol and a polyisocyanate, said ester polyol comprising a structural part derived from an alicyclic diol compound, wherein the carbamate composition did not show a crystal melting peak as confirmed by DSC analysis.

2. The carbamate composition according to claim 1, wherein, The polyisocyanate is a non-aromatic polyisocyanate.

3. The carbamate composition according to claim 1 or 2, wherein, The polyisocyanates include difunctional isocyanates and trifunctional isocyanates.

4. The carbamate composition according to claim 3, wherein, The amount of trifunctional isocyanate in the polyisocyanate is less than 45% by mass.

5. The carbamate composition according to claim 1 or 2, wherein, The polyisocyanate comprises hexamethylene diisocyanate and hexamethylene diisocyanate trimer.

6. The carbamate composition according to claim 1 or 2, wherein, The ester-based polyol is polycaprolactone polyol with a number average molecular weight of 400-800.

7. The carbamate composition according to claim 1 or 2, wherein, The carbamate composition comprises 1,4-cyclohexanediethanol as the alicyclic diol compound.

8. The carbamate composition according to claim 1 or 2, wherein, The carbamate composition is a two-component type.

9. A cured product, which is a cured product of the urethane composition according to claim 1 or 2.

10. An impact-resistant adhesive comprising the cured product according to claim 9.

11. A power semiconductor encapsulant comprising the cured product according to claim 9.

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