Adhesive tape

Abstract

To provide an adhesive tape which can achieve both a high biomass degree and high adhesive force.SOLUTION: An adhesive tape has an adhesive layer, wherein a biomass degree of the adhesive layer is 50 mass% or more, the adhesive layer contains a reactant of an urethane resin (A) and a crosslinking agent (B), the urethane resin (A) contains at least a structural unit derived from biomass polyether polyol, and a structural unit derived from aromatic polyisocyanate, and the adhesive layer satisfies any one following condition of (i) a gel fraction of 10 mass% or more and 80 mass% or less, and (ii) a stress at a strain amount of 100% in a stress-strain curve of less than 50 N / cm2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to adhesive tape. [Background technology]

[0002] Adhesive tape is used, for example, in electronic devices such as portable electronic terminals, cameras, and personal computers, as well as in their manufacturing processes, to fix protective panels for image display units to the casing, and to fix various parts such as exterior components and rigid components such as batteries.

[0003] For fastening components, adhesive tapes using acrylic adhesives are widely used. However, while acrylic adhesive tapes are low-cost, they often use petroleum as a raw material, leading to problems such as the depletion of petroleum resources and carbon dioxide emissions from waste disposal.

[0004] On the other hand, in recent years, as concern for environmental issues such as global warming has grown, there has been a strong social demand to use raw materials derived from renewable organic resources (biomass) originating from plants and animals as an alternative to conventional petroleum-derived raw materials. For this reason, development is underway to use adhesive tapes with a high biomass content as an alternative to acrylic adhesives.

[0005] For example, Patent Document 1 discloses an adhesive tape using a polyester-based adhesive composition comprising a polyester polyol obtained by polycondensation of a dicarboxylic acid having a side chain and a diol, a polyether polyol, and a crosslinking agent (Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-216875 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, adhesive tapes with adhesive layers made from biomass-derived raw materials face the challenge of not being able to meet conventional performance requirements. In particular, increasing the biomass content of the adhesive layer results in poor adhesive strength, making it difficult to improve adhesive strength while achieving a high biomass content.

[0008] Furthermore, the adhesive tape disclosed in Patent Document 1 is intended to exhibit a weak adhesive force of 1 N / 25 mm or less in both initial and long-term adhesive strength, and it is difficult to achieve a sufficiently high adhesive strength.

[0009] This invention has been made in view of the above circumstances, and aims to provide an adhesive tape that can achieve both a high biomass content and high adhesive strength. [Means for solving the problem]

[0010] To solve the above problems, the present invention provides an adhesive tape having an adhesive layer, wherein the biomass content of the adhesive layer is 50% by mass or more, the adhesive layer contains a reaction product of a urethane resin (A) and a crosslinking agent (B), the urethane resin (A) contains at least structural units derived from a biomass polyether polyol and structural units derived from an aromatic polyisocyanate, and the gel fraction of the adhesive layer is 10% by mass or more and 80% by mass or less.

[0011] Furthermore, the present invention relates to an adhesive tape having an adhesive layer, wherein the adhesive layer has a biomass content of 50% by mass or more, the adhesive layer contains a reaction product of a urethane resin (A) and a crosslinking agent (B), the urethane resin (A) contains at least structural units derived from biomass polyether polyol and structural units derived from aromatic polyisocyanate, and the adhesive layer has a stress of 50 N / cm when the strain is 100% in the stress-strain curve. 2 The present invention provides an adhesive tape characterized by being less than [amount missing]. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an adhesive tape that can achieve both a high biomass content and high adhesive strength. [Modes for carrying out the invention]

[0013] The adhesive tape of the present invention has an adhesive layer with a biomass content of 50% by mass or more. The adhesive layer in the adhesive tape of the present invention contains a reaction product of a urethane resin (A) and a crosslinking agent (B), and the urethane resin (A) contains at least structural units derived from biomass polyether polyol and structural units derived from aromatic polyisocyanate. Furthermore, the adhesive layer in the present invention has the following conditions: (i) The gel fraction is 10% by mass or more and 80% by mass or less; and (ii) In the stress-strain curve, the stress at which the strain is 100% is 50 N / cm 2 Less than; It satisfies one of the following conditions.

[0014] According to the adhesive tape of the present invention, the adhesive layer is composed of a reaction product of a urethane resin (A) containing at least structural units derived from biomass polyether polyol and structural units derived from aromatic polyisocyanate, and a crosslinking agent (B). Furthermore, by ensuring that the adhesive layer satisfies at least one of the specific physical properties of the above-described conditions (i) and (ii), it is possible to achieve both a high biomass content and high adhesive strength.

[0015] 1. Adhesive layer The adhesive layer in the present invention may have a biomass content of 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. Furthermore, a higher biomass content is preferable for the adhesive layer, but for example, it can be 98% by mass or less, preferably 95% by mass or less, and more preferably 92% by mass or less.

[0016] The biomass content of the adhesive layer is the mass ratio of the raw materials derived from biomass contained in the adhesive composition constituting the adhesive layer to the total mass of the adhesive composition constituting the adhesive layer, and can be calculated by the following calculation formula. Each mass is in terms of non-volatile content. Biomass content of the adhesive layer (mass %) = 100 × [Mass (g) of raw materials derived from biomass in the adhesive composition constituting the adhesive layer] / [Total mass (g) of the adhesive composition constituting the adhesive layer]

[0017] In the present invention, the adhesive layer can exhibit high adhesive strength while having a high biomass content when the gel fraction is 10% by mass or more and 80% by mass or less. Among them, the gel fraction of the adhesive layer is preferably 10% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and still more preferably 10% by mass or more and 50% by mass or less. By setting the gel fraction of the adhesive layer within the above range, higher adhesive strength can be ensured while having a high biomass content.

[0018] The gel fraction of the adhesive layer can be determined by the following method. First, the adhesive composition constituting the adhesive layer is coated on a release liner so that the dried thickness becomes 50 μm, dried at 100 °C for 3 minutes, and the one aged at 40 °C for 2 days is cut into a 50 mm square, which is used as a sample. Next, the mass (G1) of the sample before immersion in toluene is measured in advance, and the toluene-insoluble matter of the sample after immersion in a toluene solution at 23 °C for 24 hours is separated by filtration through a 300-mesh wire mesh, and the mass (G2) of the residue after drying at {110 °C} for 1 hour is measured. The gel fraction is calculated from the obtained G1 and G2 by the following formula. Gel fraction (mass %) = (G2 / G1) × 100

[0019] Also, in the adhesive layer of the present invention, the stress (S100) when the strain amount in the stress-strain curve is 100% is less than 50 N / cm 2 so that high adhesive strength can be exhibited even with a high biomass content. Among them, in the adhesive layer, the stress when the strain amount in the stress-strain curve is 100% is 45 N / cm 2It is preferably the following, 0.5 N / cm 2 or more and 35 N / cm or less 2 More preferably, it is the following, 0.5 N / cm 2 or more and 25 N / cm or less 2 Even more preferably, it is the following. By setting the stress at the time when the strain amount in the stress-strain curve of the adhesive layer is 100% within the above range, a higher adhesive strength can be ensured while having a high biomass degree.

[0020] The stress at the time when the strain amount in the stress-strain curve of the adhesive layer is 100% can be determined by the following method. First, the adhesive composition constituting the adhesive layer is applied onto a release liner so that the dried thickness becomes 50 μm to form an adhesive layer. Next, by laminating the above adhesive layer until the total thickness becomes about 400 μm, a test piece with a gauge length of 20 mm and a width of 10 mm is prepared. Next, this test piece is pulled at a tensile speed of 300 mm / min using a tensile testing machine under a measurement environment of a temperature of 23°C and a relative humidity of 50%, and the stress at the time when the strain amount is 100% can be determined from the stress-strain curve (so-called S-S curve) measured at that time.

[0021] The above adhesive layer in the present invention is under the following conditions: (i) The gel fraction is within a predetermined range; and (ii) The stress at the time when the strain amount in the stress-strain curve is 100% is less than a predetermined range; It is sufficient to satisfy either of the above, and it may satisfy only one of the above conditions (i) or (ii), or may satisfy both of the above conditions (i) and (ii).

[0022] The thickness of the adhesive layer in the present invention is not particularly limited, but from the viewpoint of exhibiting a high adhesive strength, it is preferably 2 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more. Also, the thickness of the above adhesive layer is preferably 200 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less.

[0023] The adhesive layer in the present invention comprises a reaction product of a urethane resin (A) and a crosslinking agent (B). In other words, the adhesive layer is composed of a reaction product (cured product) of an adhesive composition containing at least a urethane resin (A) and a crosslinking agent (B). The reaction product of the urethane resin (A) and the crosslinking agent (B) has structural units derived from the urethane resin (A) and structural units derived from the crosslinking agent (B) via urethane bonds.

[0024] The total content of the above-mentioned urethane resin (A) and crosslinking agent (B) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass in the adhesive layer (solid content of the adhesive composition). The solid content of the adhesive composition refers to the portion excluding the solvent.

[0025] <1> Urethane resin (A) The above urethane resin (A) is a reaction product of polyol (a1) and polyisocyanate (a2), and has structural units derived from polyol (a1) and structural units derived from polyisocyanate (a2) via urethane bonds. In the present invention, the above urethane resin (A) includes at least structural units derived from biomass polyether polyol and structural units derived from aromatic polyisocyanate.

[0026] In other words, the urethane resin (A) is a reaction product of a composition containing a polyol (a1) and a polyisocyanate (a2), wherein the polyol (a1) includes a biomass polyether polyol and the polyisocyanate (a2) includes an aromatic polyisocyanate.

[0027] The urethane resin (A) described above has two or more hydroxyl groups, and is preferably a hydroxyl-terminated urethane resin having hydroxyl groups at its terminal ends. In the reaction product of the urethane resin (A) and the crosslinking agent (B) that constitute the adhesive layer, the hydroxyl groups of the urethane resin (A) form crosslinks with the crosslinking agent (B).

[0028] The hydroxyl value of the above urethane resin (A) is, for example, 0.1 mg KOH / g or more, preferably 0.5 mg KOH / g or more, more preferably 1 mg KOH / g or more, preferably 40 mg KOH / g or less, more preferably 30 mg KOH / g or less, and even more preferably 25 mg KOH / g or less, because it can form crosslinks through reaction with the crosslinking agent (B) and impart cohesive force to the adhesive layer. The above hydroxyl value can be measured in accordance with JIS K0070.

[0029] The amount of urethane bond contained in the above urethane resin (A) is preferably 0.8 mmol / g, more preferably 0.85 mmol / g or more, preferably 3 mmol / g or less, more preferably 2.5 mmol / g or less, and even more preferably 2 mmol / g or less, in order to exhibit high adhesive strength.

[0030] The number average molecular weight of the above urethane resin (A) is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more, in order to exhibit high adhesive strength. Furthermore, the number average molecular weight is preferably 60,000 or less, more preferably 40,000 or less, and even more preferably 20,000 or less.

[0031] The weight-average molecular weight of the above urethane resin (A) is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more, in order to exhibit high adhesive strength. Furthermore, the weight-average molecular weight is preferably 300,000 or less, more preferably 250,000 or less, and even more preferably 200,000 or less.

[0032] The molecular weight dispersion (Mw / Mn) of the above urethane resin (A) is preferably 1.5 or higher, more preferably 2.0 or higher, even more preferably 2.5 or higher, and even more preferably 5.0 or higher. Furthermore, the molecular weight dispersion (Mw / Mn) is preferably 30 or lower, more preferably 25 or lower, even more preferably 20 or lower, and even more preferably 15 or lower. High adhesive strength can be achieved when the molecular weight dispersion of the above urethane resin (A) is within the above range.

[0033] The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the urethane resin (A) are polystyrene equivalent values ​​measured by gel permeation chromatography under the conditions described in the Examples section below.

[0034] The content of the above-mentioned urethane resin (A) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, in the adhesive layer (solid content of the adhesive composition) in order to exhibit high adhesive strength.

[0035] <<Polyol (a1)>> The polyol (a1) described above is a compound having two or more hydroxyl groups in one molecule, and the polyol (a1) contains at least biomass polyether polyol (a1-1). The polyol (a1) described above is the main component in a composition containing the polyol (a1) and polyisocyanate (a2) that form the urethane resin (A). The main component refers to the component that is present in the largest amount among the components constituting the above composition.

[0036] The biomass content of the polyol (a1) can be adjusted as appropriate, as long as it is within a range that allows the adhesive layer to exhibit a predetermined biomass content. For example, the polyol (a1) preferably has a biomass content of 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 100% by mass. This is because the unit skeleton derived from polyol (a1) accounts for a large proportion of the reaction product between the urethane resin (A) and the crosslinking agent (B) contained in the adhesive layer, thus contributing to an improvement in the biomass content of the adhesive layer.

[0037] The biomass content of the above polyol (a1) is the mass ratio of polyol (a1) derived from biomass to the total mass of polyol (a1), and can be calculated using the following formula. Note that each mass is calculated on a non-volatile content basis. Biomass content (mass%) of polyol(a1) = 100 × [Mass of biomass-derived polyol(a1) (g)] / [Total mass of polyol(a1) (g)]

[0038] <Biomass polyether polyol (a1-1)> The above-mentioned urethane resin (A) has structural units derived from biomass polyether polyol (a1-1) as structural units derived from polyol (a1). Biomass polyether polyol is a polyether polyol derived from renewable organic resources (biomass) originating from plants and animals, for example, a plant-derived polyether polyol. By including biomass polyether polyol as the main component of the above-mentioned polyol (a1), the biomass content of the urethane resin and the entire adhesive layer can be increased. The biomass content of the biomass polyether polyol is not particularly limited as long as the biomass content of the adhesive layer can be kept within a predetermined range, but it can be set, for example, in the same way as the preferred range of biomass content of the above-mentioned polyol (a1).

[0039] The content of biomass polyether polyol (a1-1) in the above polyol (a1) is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, in order to exhibit high adhesive strength. Furthermore, the upper limit of the content of biomass polyether polyol (a1-1) in the above polyol (a1) is 100% by mass, and may be 98% by mass or less.

[0040] The biomass polyether polyol (a1-1) described above may be any bifunctional or higher polyether polyol synthesized from biomass-derived materials and having at least two ether bonds in the main backbone of the molecule, or it may be a trifunctional or higher biomass polyether polyol. Furthermore, the biomass polyether polyol (a1-1) may be linear or branched. In particular, from the viewpoint of further enhancing the flexibility and adhesive strength of the adhesive layer, it is preferable that the biomass polyether polyol (a1-1) contains a linear biomass polyether diol. That is, it is preferable that the urethane resin (A) contains structural units derived from a linear biomass polyether diol.

[0041] Examples of the linear biomass polyetherdiols mentioned above include those obtained by addition polymerization of a cyclic ether using one or more low-molecular-weight compounds (e.g., molecular weight less than 500) having two active hydrogen atoms (-NH- or -OH) as initiators; and those obtained by ring-opening polymerization of a cyclic ether using an acid anhydride as an initiator, followed by transesterification with a low-molecular-weight alcohol such as methanol. The linear biomass polyetherdiols can be obtained by using biomass-derived materials for at least one of these initiators (low-molecular-weight compounds or acid-free substances having two active hydrogen atoms), the cyclic ether, and the low-molecular-weight alcohol. Examples include, but are not limited to, linear polyetherdiols obtained by addition polymerization of a biomass-derived cyclic ether using a biomass-derived low-molecular-weight compound having two active hydrogen atoms as an initiator; and linear polyetherdiols obtained by ring-opening polymerization of a biomass-derived cyclic ether using a biomass-derived acid anhydride as an initiator, followed by transesterification with a biomass-derived low-molecular-weight alcohol.

[0042] Examples of low molecular weight compounds (initiators) having two active hydrogen atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and bisphenol A, which are common compounds having two hydroxyl groups. Among the low molecular weight compounds (initiators) having two active hydrogen atoms, examples of biomass-derived compounds include ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, Examples include aliphatic glycols such as 2,2,4-trimethyl-1,5-pentanediol, 2-ethyl-2-butylpropanediol, 1,9-nonanediol, 2-methyloctanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, and 1,2-cyclohexanedimethanol; bisphenol A; polytetramethylene glycol, polypropylene glycol, polyethylene glycol, polycarbonate glycol, fatty acid esters derived from castor oil, and dimer ols and glycerol monostearates derived from oleic acid, erucic acid, etc. These can be used individually or in combination of two or more.

[0043] The above biomass-derived ethylene glycol can be produced from bioethanol. The above biomass-derived 1,3-propanediol can be produced by fermenting and decomposing plants such as corn using anaerobic bacteria to obtain glucose, which is then converted to glycerol, dehydrated to obtain 3-hydroxypropyl aldehyde (HPA), and then reduced. The biomass-derived 1,4-butanediol can be produced by producing glycol from plants, fermenting it to obtain succinic acid, and then hydrogenating it. The above 1,5-pentanediol and 1,6-pentanediol can be produced by obtaining hemicellulose from biomass, dehydrating it to obtain furfural or pyrancarbaldehyde, and then further hydrocracking it. Furthermore, polyalkylene glycols and the like can be produced by dehydration, cyclization, polymerization, etc. of these compounds.

[0044] Examples of the above-mentioned cyclic ethers include epoxide compounds such as ethylene oxide and epichlorohydrin; and cyclic ethers having 4 or more carbon atoms (preferably 4 to 6 carbon atoms, particularly preferably 4 carbon atoms), such as tetrahydrofuran. Among the above-mentioned cyclic ethers, examples of biomass-derived compounds include epoxide compounds such as ethylene oxide; and cyclic ethers such as tetrahydrofuran. The above-mentioned cyclic ethers can be produced by dehydration and cyclization of low molecular weight polyols. These can be used individually or in combination of two or more.

[0045] The above-mentioned linear biomass polyetherdiol is preferable to be non-branched because it readily exhibits adhesive strength. In other words, it is preferable that the alkylene group in the oxyalkylene unit is a linear alkylene group and does not have substituents such as alkyl groups.

[0046] The number of carbon atoms in the oxyalkylene units contained in the linear biomass polyetherdiol described above is preferably 2 or more, more preferably 3 or more, and preferably 4 or less, as this facilitates both flexibility and cohesiveness.

[0047] The content of the linear biomass polyetherdiol described above is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass, in the polyol (a1) above, in order to express a higher biomass content.

[0048] Furthermore, branched biomass polyether diols or biomass polyether polyols with three or more functions may be used as the biomass polyether polyol (a1-1) described above. These may be used alone or in combination with other biomass polyether polyols (e.g., linear biomass polyether diols). When the biomass polyether polyol (a1-1) includes both linear biomass polyether diols and biomass polyether polyols with three or more functions, the biomass polyether polyols with three or more functions can exhibit the same functions as the polyfunctional polyol (a1-2) described later.

[0049] Examples of the above-mentioned trifunctional or more biomass polyether polyols include compounds obtained by ring-opening polymerization of a cyclic ether using one or more low-molecular-weight compounds (for example, compounds with a molecular weight of 50 or more and less than 500) having three or more active hydrogen atom groups (-NH- or -OH) as initiators, and can be obtained by using biomass-derived materials for at least one of the low-molecular-weight compounds and the cyclic ether. For example, a biomass polyether polyol obtained by ring-opening polymerization of a biomass-derived cyclic ether using a biomass-derived low-molecular-weight compound as an initiator is, but is not limited to, this.

[0050] Examples of low molecular weight compounds having three or more groups containing the above-mentioned active hydrogen atoms include glycerin, trimethylolethane, and trimethylolpropane. Examples of cyclic ethers include tetrahydrofuran and alkyl-substituted tetrahydrofuran. By using biomass-derived low molecular weight compounds and / or biomass-derived cyclic ethers, trifunctional or more biomass polyether polyols can be obtained.

[0051] Specific examples of biomass polyether polyol (a1-1) include poly-1,3-propanediol and polytetramethylene ether glycol. Alternatively, the biomass polyether polyol (a1-1) may be a bifunctional biomass polyether polyol such as polyethylene glycol, polypropylene glycol, polybutylene glycol, or polytetramethylene glycol; a trifunctional biomass polyether polyol such as trimethylolpropanetripolyoxyethylene ether; a tetrafunctional biomass polyether polyol such as pentaerythritol polyoxyethylene ether; or a biomass polyether polyol such as polyoxyalkylene glycol such as polytrimethylene ether glycol.

[0052] The number-average molecular weight of the biomass polyether polyol (a1-1) depends on the type of polyether polyol used, but is preferably 500 or more, more preferably 700 or more, even more preferably 900 or more, preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less, as it is easier to achieve both flexibility and cohesiveness.

[0053] The number-average molecular weight (Mn) of the biomass polyether polyol (a1-1) represents the polystyrene equivalent value obtained by gel permeation chromatography, measured using the measurement method and conditions for the number-average molecular weight (Mn) of urethane resin described in the Examples section below.

[0054] <Polyfunctional polyols (a1-2)> The polyol (a1) described above may contain a polyfunctional polyol (a1-2) other than the biomass polyether polyol (a1-1) in order to further enhance its cohesive force. In other words, the urethane resin (a) described above may have structural units derived from polyol (a1), in addition to structural units derived from the biomass polyether polyol, derived from a polyfunctional polyol (a1-2) other than the biomass polyether polyol.

[0055] The above-mentioned polyfunctional polyols (a1-2) may be derived from biomass or petroleum (non-biomass), but it is preferable that they be derived from biomass because it can increase the biomass content of the polyol (a1) and urethane resin (a).

[0056] As the polyfunctional polyol (a1-2), any polyol with two or more functions other than the biomass polyether polyol (a1-1) can be used, and among these, polyols with three or more functions are preferred because they can exhibit high cohesive force through reaction with the biomass polyether polyol (a1-1). In particular, when the biomass polyether polyol (a1-1) includes a linear biomass polyether diol, it is even more preferable to include a polyfunctional polyol (a1-2-2) with three or more functions in addition to the biomass polyether polyol (a1-1) because it is possible to achieve both flexibility and cohesive force in the adhesive layer, thereby further enhancing the adhesive strength.

[0057] Examples of bifunctional polyols (a1-2-1) include polymer diols such as non-biomass polyether diols, polyester diols, polycarbonate diols, and polybutadiene diols; low molecular weight diols; and polyols having acidic groups.

[0058] Examples of the above-mentioned non-biomass polyether diols include those obtained by addition polymerization of a cyclic ether using one or more low-molecular-weight compounds (e.g., molecular weight less than 500) having two active hydrogen atoms (-NH or -OH) as initiators; those obtained by addition polymerization of an alkylene oxide using one or more low-molecular-weight compounds (e.g., molecular weight less than 500) having two active hydrogen atoms (-NH or -OH) as initiators; and those obtained by ring-opening polymerization of a cyclic ether using an acid anhydride as an initiator, followed by transesterification with a low-molecular-weight alcohol such as methanol.

[0059] Examples of the initiators mentioned above include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, and compounds having two hydroxyl groups such as bisphenol A.

[0060] Examples of the above-mentioned cyclic ethers include epoxide compounds such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and epichlorohydrin; and cyclic ethers having 4 or more carbon atoms (preferably 4 to 6 carbon atoms, particularly preferably 4 carbon atoms) such as tetrahydrofuran.

[0061] The above-mentioned polyester diols can include reaction products obtained by esterifying a low molecular weight diol with a dicarboxylic acid; ring-opened polymers of cyclic ester compounds such as ε-caprolactone; and copolymers of the above-mentioned esterification reaction products or ring-opened polymers.

[0062] Examples of low molecular weight diols that can be esterified with the above-mentioned dicarboxylic acids to form polyester diols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, and 1,8-octane. Examples include aliphatic diols such as diols, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, and 2-methyl-1,8-octanediol; alicyclic diols such as 1,4-cyclohexanedimethanol; hydroquinone and resorcinol; and aromatic diols such as bisphenol A, bisphenol F, and 4,4'-biphenol.

[0063] Examples of the dicarboxylic acids mentioned above include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid, as well as aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid, and their anhydrides or esterified products.

[0064] Examples of the polycarbonate diols mentioned above include reaction products obtained by reacting a carbonate ester and / or phosgene with a low molecular weight diol using one or more low molecular weight compounds having two active hydrogen atoms (for example, compounds with a molecular weight of 50 or more and less than 500) as initiators. One or more types of carbonate esters can be used, and examples include aliphatic carbonates such as alkyl carbonates (for example, methyl carbonate, ethyl carbonate, etc.) and dialkyl carbonates (for example, dimethyl carbonate, diethyl carbonate, etc.); carbonates containing alicyclic structures such as cyclocarbonates (hereinafter, "containing an alicyclic structure" may simply be referred to as "alicyclic"); and aromatic carbonates such as diphenyl carbonate.

[0065] Examples of low molecular weight diols that can react with the above-mentioned carbonate esters and phosgene include low molecular weight diols similar to those that can undergo esterification with the above-mentioned dicarboxylic acids to form polyester diols.

[0066] Examples of polyols having the above-mentioned acidic group include hydroxy acids such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid; and reaction products of the above-mentioned polyol having the above-mentioned carboxyl group and the above-mentioned polycarboxylic acid.

[0067] Examples of polyols with three or more functions (a1-2-2) include polymer polyols such as non-biomass polyether polyols, polyester polyols, polycarbonate polyols, and polybutadiene polyols; and low molecular weight polyols with a molecular weight of less than 500.

[0068] Examples of the above-mentioned non-biomass polyether polyols include those obtained by addition polymerization of alkylene oxide using one or more low-molecular-weight compounds (for example, compounds with a molecular weight of 50 or more and less than 500) having three or more active hydrogen atom groups (-NH or -OH) as initiators; and those obtained by ring-opening polymerization of cyclic ethers using one or more low-molecular-weight compounds (for example, compounds with a molecular weight of 50 or more and less than 500) having three or more active hydrogen atom groups (-NH or -OH) as initiators.

[0069] As compounds having three or more active hydrogen atoms (-NH or -OH), one or more types can be used, such as glycerin, trimethylolethane, and trimethylolpropane.

[0070] The alkylene oxides mentioned above can be one or more types, such as ethylene oxide, propylene oxide, butylene oxide, and epichlorohydrin. The cyclic ethers mentioned above can be tetrahydrofuran, alkyl-substituted tetrahydrofuran, and the like.

[0071] As the polyester polyol mentioned above, one or more low molecular weight compounds (for example, compounds with a molecular weight of 50 or more and less than 500) having three or more active hydrogen atoms (-NH or -OH) can be used as initiators to esterify the low molecular weight polyol with a polycarboxylic acid; ring-opened polymers of cyclic ester compounds such as ε-caprolactone; and copolymers of the above esterification reaction products or ring-opened polymers can be used.

[0072] Examples of low molecular weight polyols that can be esterified with the above polycarboxylic acids to form polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, and 1,8-octane. Examples include aliphatic polyols such as diols, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, and 2-methyl-1,8-octanediol; alicyclic polyols such as 1,4-cyclohexanedimethanol; hydroquinone and resorcinol; and aromatic polyols such as bisphenol A, bisphenol F, and 4,4'-biphenol.

[0073] Examples of the polycarboxylic acids mentioned above include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid, as well as aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid, and their anhydrides or esterified products.

[0074] Examples of the polycarbonate polyols mentioned above include reaction products obtained by reacting a carbonate ester and / or phosgene with a low molecular weight polyol using one or more low molecular weight compounds (for example, compounds with a molecular weight of 50 or more and less than 500) having three or more active hydrogen atoms (-NH or -OH) as initiators. One or more types of carbonate esters can be used, and examples include aliphatic carbonates such as alkyl carbonates (for example, methyl carbonate, ethyl carbonate, etc.) and dialkyl carbonates (for example, dimethyl carbonate, diethyl carbonate, etc.); carbonates containing alicyclic structures such as cyclocarbonates (hereinafter, "containing an alicyclic structure" may simply be referred to as "alicyclic"); and aromatic carbonates such as diphenyl carbonate.

[0075] Examples of low molecular weight polyols that can react with the above-mentioned carbonate esters and phosgene include low molecular weight polyols similar to those that can undergo esterification with the above-mentioned polycarboxylic acids to form polyester polyols.

[0076] The number of functional groups in the above-mentioned three- or more functional polymer polyols is three or more, preferably six or less, more preferably five or less, and even more preferably four or less, as this makes it relatively easy to control the reaction.

[0077] The molecular weight of the above-mentioned trifunctional or more polymer polyol is preferably 500 or more, more preferably 700 or more, even more preferably 900 or more, preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less, in order to efficiently impart cohesive force.

[0078] Examples of low molecular weight polyols with three or more functionalities include low molecular weight triols such as trimethylolethane and trimethylolpropane; low molecular weight tetraols such as pentaerythritol; and low molecular weight hexaols such as dipentaerythritol.

[0079] The number of functional groups in the three or more functional low molecular weight polyols is three or more, preferably six or less, more preferably five or less, and even more preferably four or less, as this makes it relatively easy to control the reaction.

[0080] The molecular weight of the above-mentioned low molecular weight polyol with three or more functions is preferably less than 500, for example, 50 or more, in order to efficiently impart cohesive force.

[0081] The content of the polyfunctional polyol (a1-2) is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.8% by mass or more in the polyol (a1). Furthermore, the content of the polyfunctional polyol (a1-2) is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less in the polyol (a1). This is because setting the content of the polyfunctional polyol (a1-2) within the above range makes it possible to improve the cohesive force through reaction with polyisocyanate (a2) while suppressing a decrease in the biomass content of the polyol (a1) and the entire adhesive layer. In particular, when the biomass polyether polyol (a1-1) contains a linear polyetherdiol, it is more preferable that the content of the trifunctional or more polyfunctional polyol (a1-2-2) is within the above range.

[0082] <Other> The polyol (a1) described above only needs to contain at least a biomass polyether polyol (a1-1), and can contain a combination of the various polyols described above. A preferred embodiment of the polyol (a1) is, for example, a composition comprising a biomass polyether diol (a1-1-1) and a trifunctional or more polyol, wherein the trifunctional or more polyol includes at least one selected from the group consisting of a trifunctional or more biomass polyether polyol (a1-1-2) and a trifunctional or more polyol other than a biomass polyether polyol (a1-2-2).

[0083] <<Polyisocyanate (a2)>> The above polyisocyanate (a2) is a compound having two or more isocyanate groups and includes at least an aromatic polyisocyanate.

[0084] The above urethane resin (A) has structural units derived from aromatic polyisocyanate as structural units derived from polyisocyanate (a2). By containing aromatic polyisocyanate as the main component, the above polyisocyanate (a2) exhibits appropriate cohesive force throughout the urethane resin and adhesive layer, thereby enhancing adhesive strength.

[0085] The content of the aromatic polyisocyanate is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 100% by mass in the polyisocyanate (a2). This is because setting the content of the aromatic polyisocyanate within the above range allows for the development of appropriate cohesive force throughout the urethane resin and adhesive layer.

[0086] Examples of the above-mentioned aromatic polyisocyanates include diphenylmethane diisocyanate (MDI; its 4,4', 2,4', or 2,2' isomers, or mixtures thereof), polymethylene polyphenyl polyisocyanate (polymeric MDI), modified MDIs such as carbodiimide-modified diphenylmethane polyisocyanate, phenylene diisocyanate, tolylene diisocyanate (TDI; its 2,4, or 2,6 isomers, or mixtures thereof), xylene diisocyanate (XDI), tetramethyl xylene diisocyanate, 1,5-naphthalene diisocyanate (NDI), tetramethyl xylylene diisocyanate, and other aromatic diisocyanates, as well as three- or more functional aromatic polyisocyanates such as their adducts, isocyanurates, and biuretes. One or more of these can be used.

[0087] In particular, the aromatic polyisocyanate is preferably one or more selected from diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), and their adducts, isocyanurates, or biuret compounds.

[0088] The above polyisocyanate (a2) may contain polyisocyanates other than the aromatic polyisocyanate, as long as the effects of the present invention are not impaired. That is, the above urethane resin (A) may have structural units derived from polyisocyanates other than aromatic polyisocyanates as structural units derived from polyisocyanate (a2).

[0089] Examples of polyisocyanates other than aromatic polyisocyanates include aliphatic polyisocyanates and alicyclic polyisocyanates. Examples of aliphatic polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate and lysine diisocyanate, and aliphatic polyisocyanates with three or more functions, such as their adducts, isocyanurates, and biuretes. Examples of alicyclic polyisocyanates include isophorone diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4- and / or 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate and 2,5- and / or 2,6-norbornane diisocyanate, dimer acid diisocyanate, bicycloheptane triisocyanate, hydrogenated xylylene diisocyanate, and other alicyclic polyisocyanates with three or more functions, such as their adducts, isocyanurates, and biuretes.

[0090] If the above polyisocyanate (a2) contains three or more functional polyisocyanates such as adducts, isocyanurates, and biurets, the content of these polyisocyanates is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, in order to exhibit cohesive force. Furthermore, the content of the three or more functional polyisocyanates is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0091] The molar ratio (NCO / OH) of isocyanate groups contained in the polyisocyanate (a2) and hydroxyl groups contained in the polyol (a1) (or, if a chain extender (a3) ​​described later is included, the sum of the hydroxyl groups contained in the polyol (a1) and the active hydrogen atoms contained in the chain extender (a3)) is 0.5 or higher, preferably 0.55 or higher, more preferably 0.6 or higher, less than 1, and preferably 0.9999 or lower, in order to exhibit cohesive force.

[0092] The polyisocyanate (a2) described above may be a biomass-derived polyisocyanate (biomass polyisocyanate) or a petroleum-derived polyisocyanate (non-biomass polyisocyanate). Among these, a biomass polyisocyanate is more preferable because it can increase the biomass content of the urethane resin and adhesive layer.

[0093] <Chain elongator (a3)> The urethane resin (A) may be obtained by further reacting a chain extender (a3) ​​with the reaction product of the polyol (a1) and the polyisocyanate (a2). That is, the urethane resin (A) may be the reaction product of a composition containing the polyol (a1), the polyisocyanate (a2), and the chain extender (a3), or more specifically, the reaction product of a composition containing the reaction product of the polyol (a1) and the polyisocyanate (a2) and the chain extender (a3).

[0094] As the above chain extender (a3), one or more than one kind can be used, and examples include compounds having two or more active hydrogen atoms and polyamines. Examples of the compound having two or more active hydrogen atoms include aliphatic chain extenders such as ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 3,3'-dimethylolheptane, neopentyl glycol, 3,3-bis(hydroxymethyl)heptane, diethylene glycol, dipropylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, glycerin, trimethylolpropane; 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo[5.2.1.0 2,6Examples of alicyclic chain extenders include decane-dimethanol, bicyclo[4.3.0]-nonanediol, dicyclohexanediol, bicyclo[4.3.0]nonanedimethanol, spiro[3.4]octanediol, butylcyclohexanediol, 1,1'-bicyclohexylidenediol, cyclohexanetriol, hydrogenated bisphenol A, and 1,3-adamantanediol. Aliphatic alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol; and alicyclic glycols such as cyclohexanedimethanol are preferred. Furthermore, the above polyamines include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, N-hydroxymethylaminoethylamine, N-ethylaminoethylamine, N-methylaminopropylamine, diethylenetriamine, and dipropylenetriamine. Examples of polyamine extenders include amines, triethylenetetramine, hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine, succinate dihydrazide, adipic acid dihydrazide, glutarate dihydrazide, sebacate dihydrazide, isophthalate dihydrazide, β-semicarbazidepropionate hydrazide, 3-semicarbazide-propylcarbasic acid ester, and semicarbazide-3-semicarbazidemethyl-3,5,5-trimethylcyclohexane.

[0095] Since the above-mentioned chain extender (a3) ​​can exert cohesive force on the urethane resin, it is preferably in the range of 0 to 5 parts by mass, more preferably in the range of 0 to 3 parts by mass, and even more preferably in the range of 0 to 1 part by mass, per 100 parts by mass of the above-mentioned polyol (a1).

[0096] The above-mentioned chain extender (a3) ​​may be petroleum-derived or biomass-derived. Of these, biomass-derived is more preferable because it can increase the biomass content of the urethane resin and adhesive layer.

[0097] <Terminal inhibitors (a4)> The above-mentioned urethane resin (A) may be obtained by reacting the reaction product of the above-mentioned polyol (a1), polyisocyanate (a2), and a chain extender (a3) ​​used as needed with an end-terminating agent (a4). By using the end-terminating agent (a4), the isocyanate group can be deactivated.

[0098] The end-terminating agent (a4) is preferably an alcohol, and examples include monofunctional alcohols such as methanol, ethanol, propanol, and butanol; difunctional alcohols such as 1,2-propylene glycol and 1,3-butylene glycol; polyfunctional polyols; and alkanolamine compounds such as alkanolamines (e.g., ethanolamine) and alkanoldiamines (e.g., diethanolamine).

[0099] The upper terminal stopper (a4) may be petroleum-derived or biomass-derived. Of these, biomass-derived is more preferable because it can increase the biomass content of the urethane resin and adhesive layer.

[0100] <Other> The above urethane resin (A) can be produced by copolymerizing a polyol (a1) and a polyisocyanate (a2), and further reacting with a chain extender (a3) ​​and / or an end-terminating agent (a4) as needed. The above reaction may be carried out in the presence of an organic solvent, and a urethane catalyst may be present during the reaction.

[0101] The above organic solvents can be one or more types, and examples include aromatic hydrocarbon solvents such as toluene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and 3-pentanone; ether solvents such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, and ethyl carbitol; nitrile solvents such as acetonitrile, propionitrile, isobutyronitrile, and valeronitrile; sulfoxide solvents such as dimethyl sulfoxide; and amide solvents such as methylformamide, dimethylacetamide, and N-methyl-2-pyrrolidone.

[0102] Examples of urethane catalysts that can be used include nitrogen-containing compounds such as triethylamine, triethylenediamine, and N-methylmorpholine; metal salts such as potassium acetate, zinc stearate, and tin octoate; and organometallic compounds such as dibutyltin laurate, dioctyltin dineodecanate, and zirconium tetraacetylacetonate.

[0103] The above urethane resin (A) contains at least structural units derived from biomass polyether polyols and structural units derived from aromatic polyisocyanates, but may further contain structural units derived from trifunctional or higher polyols. The structural units derived from trifunctional or higher polyols contained in the above urethane resin (A) may be, for example, structural units derived from trifunctional or higher biomass polyether polyols, structural units derived from trifunctional or higher polyfunctional polyols (a1-2) other than biomass polyether polyols, or both.

[0104] Examples of the above-mentioned urethane resin (A) having the structural units described above include the following embodiments. In one embodiment, the urethane resin (A) can be a reaction product of a composition containing at least a polyol (a1) containing a trifunctional or more functional biomass polyether polyol (a1-1) and a polyisocyanate (a2) containing an aromatic polyisocyanate (a2). In another embodiment, the urethane resin (A) can be a reaction product of a composition containing at least a polyol (a1) containing a bifunctional or trifunctional or more functional biomass polyether polyol (a1-1) and a trifunctional or more functional polyol (a1-2) other than the biomass polyether polyol (a1-1), and a polyisocyanate (a2) containing an aromatic polyisocyanate. In particular, the urethane resin (A) can be a reaction product of a composition containing at least one of a linear biomass polyether polyol (a1-1-1), a trifunctional or more biomass polyether polyol (a1-1-2), and a trifunctional or more polyfunctional polyol (a1-2) other than the biomass polyether polyol (a1-1), and a polyisocyanate (a2) containing the aromatic polyisocyanate.

[0105] Furthermore, the urethane resin (A) may further contain structural units derived from a chain extender (a3) ​​in addition to structural units derived from a biomass polyether polyol and structural units derived from an aromatic polyisocyanate. As the urethane resin (A) having the above-mentioned structural units, for example, the urethane resin (A) may be a reaction product of a composition containing a polyol (a1) containing the biomass polyether polyol (a1-1), a polyisocyanate (a2) containing the aromatic polyisocyanate, and a chain extender (a3). More specifically, it may be a reaction product of a composition containing a polyol (a1) containing the biomass polyether polyol (a1-1), a polyisocyanate (a2) containing the aromatic polyisocyanate, and a chain extender (a3).

[0106] <2> Crosslinking agent (B) The above-mentioned crosslinking agent (B) only needs to be able to react with the urethane resin (A) to form a reactant (cured product), and a compound having two or more groups that can react with hydroxyl groups in one molecule is preferred. Examples of such crosslinking agents (B) include isocyanate compounds having two or more isocyanate groups in one molecule; epoxy compounds having two or more epoxy groups in one molecule, etc. Among these, it is preferable to include an isocyanate compound because it can exhibit high adhesive strength.

[0107] The above-mentioned isocyanate compounds can include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and the like. The isocyanate compounds may be used individually or in combination of two or more.

[0108] Examples of the above-mentioned aliphatic polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), dimer acid diisocyanate, norbornene diisocyanate, lysine diisocyanate, and tetramethylxylylene diisocyanate, as well as aliphatic polyisocyanates with three or more functionalities, such as their adducts, isocyanurates, and biuretes. These may be used individually or in combination of two or more.

[0109] Examples of the above-mentioned alicyclic polyisocyanates include isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, alicyclic diisocyanates of isophorone diisocyanate, and alicyclic polyisocyanates with three or more functions, such as their adducts, isocyanurates, and biuretes. These may be used individually or in combination of two or more.

[0110] Examples of the above-mentioned aromatic polyisocyanates include diphenylmethane diisocyanate (MDI; its 4,4', 2,4', or 2,2' isomer, or mixtures thereof), polymethylene polyphenyl polyisocyanate (polymeric MDI), modified MDI such as carbodiimide-modified diphenylmethane polyisocyanate, phenylene diisocyanate, tolylene diisocyanate (TDI; its 2,4, or 2,6 isomer, or mixtures thereof), xylene diisocyanate (XDI), tetramethyl xylene diisocyanate, 1,5-naphthalene diisocyanate (NDI), tetramethyl xylylene diisocyanate, and other aromatic diisocyanates, as well as three- or more functional aromatic polyisocyanates such as their adducts, isocyanurates, and biuretes. These may be used individually or in combination of two or more.

[0111] In particular, as the isocyanate compound, aliphatic polyisocyanates or aromatic polyisocyanates are preferred because they can exhibit high adhesive strength in the adhesive layer through reaction with urethane resin (A), and trifunctional or higher aromatic polyisocyanates are preferred because they can further enhance the adhesive strength of the adhesive layer.

[0112] The amount of the above-mentioned isocyanate compound is preferably such that the equivalent ratio of the hydroxyl groups in the above-mentioned urethane resin (A) to the isocyanate groups of the above-mentioned isocyanate crosslinking agent is 0.1 or more, more preferably 0.15 or more, even more preferably 0.2 or more, and preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less, in order to achieve high adhesive strength.

[0113] The epoxy compounds mentioned above can be one or more, for example, diglycidyl ethers of aliphatic, alicyclic or aromatic polyol compounds such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, cyclohexanedimethanol diglycidyl ether, resorcinol diglycidyl ether, phenol (EO) 5 glycidyl ether, bis-(p-hydroxyphenyl)methane diglycidyl ether, 2,2-bis-(p-hydroxyphenyl)propane diglycidyl ether, tris-(p-hydroxyphenyl)methane polyglycidyl ether, 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane polyglycidyl ether, lauryl alcohol (EO) 15 glycidyl ether, glycerin triglycidyl ether, diglycerin Polyglycidyl ethers of aliphatic, alicyclic, or aromatic polyol compounds such as polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, and diglycerol polyglycidyl ether; N,N-diglycidylaniline, N,N-diglycidyltoluidine 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N Polyglycidyl ethers of amine compounds such as ',N'-tetraglycidyl-m-xylenediamine and N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane; diglycidyl esters or polyglycidyl esters of fatty acids or aromatic acids such as diglycidyl terephthalate, diglycidyl isophthalate, diglycidyl naphthalenedicarboxylic acid, polyglycidyl trimellitic acid, diglycidyl adipic acid, and diglycidyl sebacate; triglycidylaminophenol;Examples include triglycidyl tris(2-hydroxyethyl) isocyanurate, triglycidyl isocyanurate, orthocresol-type epoxy, and phenol novolac-type epoxy.

[0114] The amount of the epoxy compound is such that, in order to exhibit high adhesive strength, the equivalent ratio of hydroxyl groups in the urethane resin (A) to epoxy groups in the epoxy compound is preferably 1 or more, more preferably 1.2 or more, even more preferably 1.5 or more, and preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.

[0115] The content of the above-mentioned isocyanate compound is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass, in the above-mentioned crosslinking agent (B), in order to exhibit high adhesive strength.

[0116] The amount of the crosslinking agent (B) described above should be such that the adhesive layer achieves the above-described physical properties. Preferably, it is 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.2 parts by mass or more and 7 parts by mass or less, and even more preferably 0.2 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the urethane resin (A). By setting the amount of the crosslinking agent (B) that reacts with the urethane resin (A) within the above range, the gel fraction of the adhesive layer and the stress at which the strain amount is 100% in the stress-strain curve can be adjusted to a predetermined range, thereby achieving high adhesive strength.

[0117] The crosslinking agent (B) may be petroleum-derived or biomass-derived. In particular, it is more preferable that the crosslinking agent (B) is biomass-derived because it can increase the biomass content of the urethane resin and adhesive layer.

[0118] <3> Any ingredient The above adhesive layer (adhesive composition) may further contain a curing catalyst. The curing catalyst may be a compound similar to the one exemplified as the urethane catalyst. When the curing catalyst is included, its content is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.01 parts by mass or more, preferably 1 part by mass or less, more preferably 0.1 parts by mass or less, and even more preferably 0.05 parts by mass or less, per 100 parts by mass of the above urethane resin (A).

[0119] The above-mentioned adhesive layer (adhesive composition) may further contain other additives such as plasticizers, silane coupling agents, antioxidants, light stabilizers, rust inhibitors, thixotropic agents, sensitizers, polymerization inhibitors, leveling agents, tackifiers, antistatic agents, and flame retardants.

[0120] 2. Any configuration The adhesive tape of the present invention only needs to have at least the adhesive layer described above, but it can have any configuration as needed.

[0121] <Base material> The adhesive tape of the present invention may have a base material. The base material has the function of supporting the adhesive layer in the adhesive tape. As the base material, resin films, foams, woven fabrics, nonwoven fabrics, metal foils, glass sheets, papers, and composite base materials with a composite structure thereof can be used. Resin films are distinguished from foams in that they are non-foamed. Among these, it is more preferable that the base material has a biomass-derived raw material content of 50% by mass or more, as this can improve the overall biomass content of the adhesive tape.

[0122] As the resin film mentioned above, sheets or films obtained using polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyolefin resins such as polyethylene and polypropylene; polyacrylic resins; polyvinyl chloride resins; polypropylene ethylene vinyl alcohol; polyvinyl alcohol resins; polyurethane resins; polyamide resins; and polyimide resins may be used. The surface of the resin film may be treated with antistatic treatment, corona treatment, etc.

[0123] Examples of the foams that can be used include polyolefin foams, polyurethane foams, acrylic foams, and other rubber foams. The surface of the foam substrate may be treated with antistatic treatment, corona treatment, etc.

[0124] Examples of the woven or nonwoven fabrics mentioned above include Manila hemp, wood pulp, rayon, acetate fibers, polyester fibers, vinylon fibers (polyvinyl alcohol fibers), polyamide fibers and other chemical fibers, and mixtures thereof.

[0125] Examples of the above types of paper include Japanese paper (washi), high-quality paper, kraft paper, and crepe paper. Examples of the above types of metal foil include aluminum foil and copper foil.

[0126] Examples of the above-mentioned composite substrates include laminated sheets of a resin film and a metal layer or metal oxide layer, such as a metal foil, metal sputtered layer, metal vapor deposition layer, or metal plating layer, and resin sheets reinforced with inorganic fibers such as glass cloth.

[0127] The above-mentioned substrate may further include an intermediate layer, a primer layer, and so on.

[0128] The thickness of the above-mentioned substrate can be appropriately selected depending on its material and form, but for example, it is preferably 1000 μm or less, more preferably about 1 μm to 1000 μm, particularly preferably about 2 μm to 500 μm, even more preferably about 3 μm to 300 μm, and particularly preferably about 5 μm to 250 μm.

[0129] <Release Liner> The adhesive tape of the present invention preferably has a release liner on the surface of the adhesive layer. This protects the surface of the adhesive layer until use and is also useful in terms of workability and other factors.

[0130] The release liner is not particularly limited, and conventionally known types can be used as appropriate. For example, a release liner substrate can be used in which a release agent (release agent) such as a silicone-based release agent, a fluorine-based release agent, a long-chain alkyl-based release agent, or a fatty acid amide-based release agent is coated on at least one side. The release liner substrate can be in single-layer or multi-layer form.

[0131] Various thin materials such as plastic films, paper, foams, and metal foils can be used as the base material for the release liner, with plastic films being particularly preferred. Examples of raw materials for the plastic film include polyesters such as polyethylene terephthalate, polyolefins such as polypropylene and ethylene-propylene copolymers, and thermoplastic resins such as polyvinyl chloride. In addition, plastic films made from polylactic acid, polyester, polyamides obtained from biomass-derived raw materials, and paper can be suitably used.

[0132] The above-mentioned release liner is preferably provided on at least one adhesive surface of the adhesive tape, but may also be provided on both adhesive surfaces of the adhesive tape.

[0133] <Other configurations> The adhesive tape of the present invention may have any layer in its composition depending on its application and other factors.

[0134] 3. Other properties of adhesive tape The adhesive tape of the present invention may be a so-called substrate-less adhesive tape in which opposing main surfaces of the adhesive layer each become the adhesive surface of the adhesive tape, or it may be a single-sided adhesive tape or a double-sided adhesive tape in which the adhesive layer is provided directly or via another layer on one or both sides of the substrate. In the case of a double-sided adhesive tape having a substrate, the adhesive layer provided on at least one side of the substrate may be the adhesive layer described in the "1. Adhesive Layer" section above, and it is more preferable from the viewpoint of increasing the biomass content of the entire adhesive tape if the adhesive layers provided on both sides of the substrate are the adhesive layers described in the "1. Adhesive Layer" section above. Furthermore, if the adhesive tape of the present invention has a substrate, it is preferable that the adhesive layer described in the "1. Adhesive Layer" section above becomes the adhesive surface of the adhesive tape.

[0135] The form of the adhesive tape of the present invention is not particularly limited and may be in the form of a roll or a single sheet. Furthermore, the total thickness of the adhesive tape of the present invention is not particularly limited and can be set as appropriate depending on the application, etc.

[0136] From the viewpoint of exhibiting high adhesive strength even with a high biomass content, the adhesive tape of the present invention preferably has a 180° peel adhesive strength to a stainless steel plate of 3N / 20mm or more, more preferably 5N / 20mm or more, and even more preferably 8N / 20mm or more.

[0137] The 180° peel adhesion strength of the adhesive tape of the present invention to a stainless steel plate can be measured by the following method. First, one side of the adhesive tape is backed with a 25 μm thick polyethylene terephthalate film and cut to a width of 20 mm to prepare a test piece. Next, the test piece is attached to the surface of a clean and smooth stainless steel plate so that the adhesive area is 20 mm × 60 mm. Pressure is applied to the upper surface by passing a 2 kg roller back and forth once, and then the tape is attached by passing a 2 kg roll back and forth once. After pressure is applied, the test piece is left for 1 hour under conditions of 23°C and 50% RH in accordance with JIS Z-0237. Then, the 180° peel adhesion strength of the adhesive tape to a stainless steel (SUS) plate can be measured by using a tensile testing machine under the conditions of peel direction: 180° and tensile speed: 0.3 m / min in an atmosphere of 23°C and 50% RH.

[0138] 4. Method for manufacturing adhesive tape The method for manufacturing the adhesive tape of the present invention is not particularly limited, and known methods can be used depending on the configuration of the adhesive tape. For example, a method for manufacturing a substrate-less adhesive tape includes coating the adhesive compound onto a release liner, drying and curing it to form an adhesive layer, and, if necessary, laminating a release liner to the other main surface of the adhesive layer. Furthermore, a method for manufacturing an adhesive tape having a substrate includes, for example, a method in which the adhesive composition is coated onto one or both sides of the substrate and dried (direct method), or a method in which the adhesive composition is coated onto the surface of a release liner and dried to form an adhesive layer, and then the adhesive layer is transferred to one or both sides of the substrate (transfer method).

[0139] In the manufacture of the above-mentioned adhesive tape, the adhesive composition may be mixed with a known solvent as needed and used as a solution of the adhesive composition. Methods for applying the adhesive composition include coating using a roll coater, gravure coater, reverse coater, spray coater, air knife coater, die coater, etc.

[0140] One method for drying the above adhesive composition after application is to dry it at 50°C to 140°C for 30 seconds to 10 minutes. Furthermore, to promote the curing reaction after drying, further aging may be performed in the range of 30°C to 50°C.

[0141] 5.Applications The adhesive tape of the present invention is capable of achieving both a high biomass content and high adhesive strength, and is particularly useful as an adhesive tape used in electronic devices such as portable electronic terminals, cameras, and personal computers, and in their manufacturing processes, for fixing protective panels of image display units to housings, or for fixing rigid parts such as exterior components and batteries.

[0142] The present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention. [Examples]

[0143] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0144] The number-average molecular weight and weight-average molecular weight of the urethane resin were measured using the following GPC measurement method. [GPC measurement method] Measurement device: High-speed GPC device (HLC-8220GPC manufactured by Tosoh Corporation) Columns: The following columns manufactured by Tosoh Corporation were used, connected in series. (1) TSK-GEL HXL-H (Guard Column) (2) TSK-GEL GMHXL (3) TSK GEL GMHXL (4) TSK-GEL GMHXL (5) TSK-GEL GMHXL Sample concentration: Diluted with tetrahydrofuran to 4 mg / mL. Mobile phase solvent: tetrahydrofuran Flow rate: 1.0mL / min Injection volume: 100μL Column temperature: 40℃ Standard samples: Calibration curves were prepared using the following standard polystyrene samples. (Standard polystyrene) TSKgel Standard Polystyrene A-500, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene A-1000, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene A-2500, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene A-5000, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-1, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-2, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-4, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-10, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-20, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-40, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-80, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-128, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-288, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-550, manufactured by Tosoh Corporation. TSKgel Standard Polystyrene F-850, manufactured by Tosoh Corporation.

[0145] (Example 1) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 847 parts by mass of biomass poly(1,3-propanediol) ("PPD-1") as a linear biomass polyether polyol (a1-1), 20 parts by mass of polypropylene glycol glyceryl ether ("Uniol TG-330", manufactured by NOF Corporation, trifunctional polyol, number average molecular weight: 330) as a polyfunctional polyol (a1-2), 133 parts by mass of tolylene diisocyanate (TDI) as a polyisocyanate (a2), and 428 parts by mass of methyl ethyl ketone (MEK) were added. After raising the temperature inside the reaction vessel to 40°C, 0.2 parts by mass of tin octylate ("Neostan U-28", manufactured by Nitto Chemical Co., Ltd.) was added, and the temperature was raised to 75°C over 1 hour. Subsequently, the mixture was held at 75°C for 12 hours to confirm that all isocyanate groups had disappeared. The reaction was then stopped with 1.1 parts by mass of 1,3-butanediol (1,3-BG), and 571 parts by mass of MEK was added to obtain a MEK solution of urethane resin (A-1) (solid content 50% by mass). The number-average molecular weight of the obtained urethane resin (A-1) was 4,300, and the weight-average molecular weight was 14,200.

[0146] Adhesive composition (1) was obtained by blending 2.7 parts by mass of isocyanurate of hexamethylene diisocyanate (D-100K) as a crosslinking agent (B) with 100 parts by mass of urethane resin (A-1), and further blending 0.02 parts by mass of dioctyl tin dieodecanate as a curing catalyst.

[0147] The adhesive composition (1) was applied to the heavily peeled surface of a release liner (125 μm thick release paper with release treatment on both sides) S1 and dried at 85°C for 3 minutes. After the adhesive composition (1) dried, the lightly peeled surface of another release liner (125 μm thick release paper with release treatment on both sides) S2 was bonded to the coating film and cured at 40°C for 48 hours to obtain a substrate-less adhesive tape (1) with a thickness of 50 μm.

[0148] (Examples 2-23, Comparative Examples 1-12) MEK solutions (50% solids by mass) of urethane resins (A-2) to (A-13) were obtained in the same manner as in Example 1, except that the compounds and their proportions used in the synthesis of urethane resin (A-1) in Example 1 were changed to the compounds and proportions shown in Table 1. Subsequently, adhesive compositions (2) to (35) were obtained in the same manner as in Example 1, except that 100 parts by mass of the solids of urethane resins (A-2) to (A-13) were reacted with the compounds and proportions shown in Table 1 as the crosslinking agent (B). Next, substrate-less adhesive tapes (2) to (35) with a thickness of 50 μm were obtained in the same manner as in Example 1, except that adhesive compositions (2) to (35) were used instead of adhesive composition (1).

[0149] [Evaluation 1: Biomass content of the adhesive layer] The mass ratio of biomass-derived raw materials contained in the adhesive composition to the total mass of the adhesive composition constituting the adhesive layer of the adhesive tapes obtained in the examples and comparative examples was calculated using the following formula. Note that each mass is on a non-volatile content basis (solid content basis). Biomass content (mass %) of the adhesive layer = 100 × [Mass of biomass-derived raw materials in the adhesive composition constituting the adhesive layer (g)] / [Total mass of the adhesive composition constituting the adhesive layer (g)]

[0150] [Evaluation 2: Gel fraction of the adhesive layer] The adhesive composition (solids) used to form the adhesive layer of the adhesive tapes obtained in the examples and comparative examples was coated onto a release liner to a dry thickness of 50 μm, dried at 100°C for 3 minutes, and aged at 40°C for 2 days. The resulting sample was cut into 50 mm squares and used as the sample. Next, the mass of the sample before immersion in toluene (G1) was measured in advance. After immersion in toluene solution at 23°C for 24 hours, the toluene-insoluble portion of the sample was separated by filtration through a 300-mesh wire mesh. The mass of the residue after drying at 110°C for 1 hour (G2) was measured, and the gel fraction was determined according to the following formula. Gel fraction (mass %) = (G2 / G1) × 100

[0151] [Evaluation 3: Stress when the strain of the adhesive layer in the stress-strain curve is 100%] Test specimens with a gauge spacing of 20 mm and a width of 10 mm were prepared by laminating each adhesive tape obtained in the examples and comparative examples until the total thickness of the adhesive layer reached approximately 400 μm. These test specimens were pulled using a tensile testing machine at a tensile speed of 300 mm / min under measurement conditions of 23°C and 50% relative humidity, and the stress at which the strain reached 100% was determined from the stress-strain curve (so-called SS curve) measured at that time.

[0152] [Evaluation 4: 180° peel adhesion strength of adhesive tape to stainless steel (SUS) plate] After peeling off the release liner S2 from each adhesive tape obtained in the examples and comparative examples, the tapes were backed with a 25 μm thick polyethylene terephthalate film and cut into 20 mm wide strips to prepare the test pieces. The release liner S1 was peeled off the test pieces and attached to the surface of a clean, smooth stainless steel plate so that the adhesive area was 20 mm × 60 mm. Pressure was applied to the top surface by running a 2 kg roller back and forth once, and then the tape was adhered by running a 2 kg roll back and forth once. After pressure was applied, the test pieces were left for 1 hour under conditions of 23°C and 50% RH in accordance with JIS Z-0237, and then peeled off using a tensile testing machine under an atmosphere of 23°C and 50% RH to measure the 180° peel adhesive strength (peel direction: 180°, tensile speed: 0.3 m / min) of the adhesive tape to the stainless steel (SUS) plate.

[0153] The compositions and evaluation results of the adhesive compositions (1) to (35) obtained above are shown in Tables 1 to 3. In the tables, each abbreviation represents the following compound. <Polyether polyol> • "PPD-1": Biomass poly(1,3-propanediol) (number average molecular weight: 1000, hydroxyl value: 105.2 mgKOH / g) • "PPD-2": Biomass poly(1,3-propanediol) (number-average molecular weight: 2000, hydroxyl value: 55.1 mgKOH / g) <Polyfunctional polyols> "TG-330": Polypropylene glycol glyceryl ether ("Uniol TG-330", manufactured by NOF Corporation, number average molecular weight: 330, hydroxyl value: 502 mg KOH / g) "TMP": Trimethylolpropane <Polyisocyanate> "HDI": Hexamethylene diisocyanate "TDI": Tolylene diisocyanate "MDI": 4,4'-diphenylmethane diisocyanate "T1890 / 100": Isocyanurate derivative of isophorone diisocyanate having three or more isocyanates ("VESTANAT T1890 / 100", manufactured by Evonik, NCO%; 17.1% by mass) <Chain elongators> "14BG": 1,4-Butylene glycol <crosslinking agent> "D-100K": Isocyanurate derivative of hexamethylene diisocyanate ("FINETACK HARDENER D-100K", manufactured by DIC Corporation, NCO%; 21.8% by mass) "D-40": Adduct of tolylene diisocyanate ("Barnock D-40", manufactured by DIC Corporation, NCO%; 7.1% by mass)

[0154] [Table 1]

[0155] [Table 2]

[0156] [Table 3]

[0157] From the evaluation results above, it became clear that the adhesive tape of the example has an adhesive layer composed of a reaction product of a urethane resin (A) containing at least structural units derived from biomass polyether polyol and structural units derived from aromatic polyisocyanate, and a crosslinking agent (B), and that the adhesive layer satisfies specific physical properties, thereby enabling both a high biomass content and high adhesive strength.

[0158] On the other hand, the comparative adhesive tape showed low adhesive strength when the urethane resin (A) did not contain structural units derived from aromatic polyisocyanate, even when the gel fraction and the stress at 100% strain in the adhesive layer of the stress-strain curve met the conditions. Furthermore, even when the urethane resin (A) contained structural units derived from aromatic polyisocyanate, it was shown that low adhesive strength was still present if the gel fraction and the stress at 100% strain in the adhesive layer of the stress-strain curve did not meet the conditions.

Claims

1. An adhesive tape having an adhesive layer, The biomass content of the adhesive layer is 50% by mass or more. The adhesive layer contains a reaction product of urethane resin (A) and crosslinking agent (B), The urethane resin (A) contains at least structural units derived from linear biomass polyetherdiol and structural units derived from aromatic polyisocyanate, The crosslinking agent (B) is in an amount of 0.1 parts by mass or more and 3.5 parts by mass or less per 100 parts by mass of the urethane resin (A), and contains a trifunctional or more polyisocyanate compound. The gel fraction of the adhesive layer is 10% by mass or more and 80% by mass or less. An adhesive tape characterized by having a 180° peel adhesion strength of 3N / 20mm or more to a stainless steel plate.

2. An adhesive tape having an adhesive layer, The biomass content of the adhesive layer is 50% by mass or more. The adhesive layer contains a reaction product of urethane resin (A) and crosslinking agent (B), The urethane resin (A) contains at least structural units derived from linear biomass polyetherdiol and structural units derived from aromatic polyisocyanate, The crosslinking agent (B) is in an amount of 0.1 parts by mass or more and 3.5 parts by mass or less per 100 parts by mass of the urethane resin (A), and contains a trifunctional or more polyisocyanate compound. The adhesive layer has a stress of less than 50 N / cm² when the strain is 100% in the stress-strain curve. An adhesive tape characterized by having a 180° peel adhesion strength of 3N / 20mm or more to a stainless steel plate.

3. The urethane resin (A) further comprises structural units derived from a polyol with three or more functionalities. The adhesive tape according to either claim 1 or 2.

4. The weight-average molecular weight of the urethane resin (A) is 10,000 or more and 300,000 or less. The adhesive tape according to any one of claims 1 to 3, characterized by the following:

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