Compound, method for producing compound, adhesive composition, and adhesive tape

Abstract

The object of this invention is to provide a compound capable of improving the adhesive strength of an adhesive composition, particularly for substrates with low polarity. Furthermore, the object of this invention is to provide a method for manufacturing the compound, an adhesive composition containing the compound, and an adhesive tape having an adhesive layer containing the adhesive composition. This invention pertains to a compound having at least one structural unit (A) selected from structural units (A-1) and (A-1') shown in the following formula. Wherein, R... 1 They represent hydrogen atoms, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, polar functional groups, aliphatic hydrocarbon groups with polar functional groups, or aromatic hydrocarbon groups with polar functional groups, respectively. n represents an integer greater than or equal to 2 and less than or equal to 4, and n' represents an integer greater than or equal to 2 and less than or equal to 5.

Description

Technical Field

[0001] This invention relates to compounds that can be used in adhesive compositions. Furthermore, this invention relates to methods for manufacturing the compound, adhesive compositions containing the compound, and adhesive tapes having adhesive layers containing the adhesive composition. Background Technology

[0002] Adhesive tape has long been widely used for securing components in electronic devices. Specifically, adhesive tape is used, for example, to bond a cover plate used to protect the surface of a portable electronic device to a touch panel module or a display panel module, or to bond a touch panel module to a display panel module. For adhesive tape used to secure such electronic device components, in addition to high adhesion, it is also required to have properties such as heat resistance, thermal conductivity, and impact resistance, depending on the environment of the location where it is used (e.g., Patent Documents 1-3).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-052050

[0006] Patent Document 2: Japanese Patent Application Publication No. 2015-021067

[0007] Patent Document 3: Japanese Patent Application Publication No. 2015-120876 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] To improve adhesion, adhesive compositions in which tackifying resins are added to a base polymer are known. Tackifying resins typically alter the bulk mechanical properties and surface polarity of the base polymer, thereby increasing adhesive strength.

[0010] In recent years, the applications of adhesive tapes have expanded, demanding higher performance from adhesive compositions. For example, adhesive tapes used to fix electronic device components are becoming thinner, requiring high adhesive strength even in thinner versions. Furthermore, the types of substrates being bonded are diversifying, with the use of more difficult-to-bond substrates, such as those containing polyolefin resins and other low-polarity substrates. In such cases, conventional adhesive compositions may fail to achieve sufficient adhesive strength.

[0011] The object of this invention is to provide a compound capable of improving the adhesive strength of an adhesive composition, particularly for substrates with low polarity. Furthermore, the object of this invention is to provide a method for manufacturing the compound, an adhesive composition containing the compound, and an adhesive tape having an adhesive layer containing the adhesive composition.

[0012] Methods for solving problems

[0013] The present invention relates to compounds having at least one structural unit (A) selected from structural units (A-1) and structural units (A-1') shown in the following formula. The present invention will be described in detail below.

[0014]

Chemical Formula 1

[0015]

[0016] In the formula, R 1 They represent hydrogen atoms, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, polar functional groups, aliphatic hydrocarbon groups with polar functional groups, or aromatic hydrocarbon groups with polar functional groups, respectively. n represents an integer greater than or equal to 2 and less than or equal to 4, and n' represents an integer greater than or equal to 2 and less than or equal to 5.

[0017] The inventors have successfully manufactured a novel compound containing a specific structural unit (A) having a phenolic hydroxyl group. The inventors have discovered that by incorporating such a compound as a tackifying resin into an adhesive composition, the adhesive strength of the adhesive composition can be improved, particularly for substrates with low polarity, thus completing the present invention.

[0018] The compounds of the present invention have at least one structural unit (A) selected from structural units (A-1) and structural units (A-1') shown in the following formula.

[0019] By having such a structural unit (A) with phenolic hydroxyl groups, the compounds of the present invention can improve the adhesive strength of adhesive compositions, and in particular, can significantly improve the interaction with low-polarity substrates, thus improving the adhesive strength even for low-polarity substrates. Therefore, the compounds of the present invention are suitable for use as tackifying resins in conjunction with adhesive compositions.

[0020] The compounds of the present invention may have at least one structural unit (A) selected from structural units (A-1) and structural units (A-1') shown in the following formula in the side chain, or may have it in the main chain backbone or at the end of the main chain backbone. Preferably, from the aspect of being able to have suitable physical properties required for use as a tackifying resin, the compounds of the present invention have at least one structural unit (A) selected from structural units (A-1) and structural units (A-1') shown in the following formula in the main chain backbone or at the end of the main chain backbone.

[0021]

Chemical Formula 2

[0022]

[0023] In the formula, R 1 These represent hydrogen atoms, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, polar functional groups, aliphatic hydrocarbon groups with polar functional groups, or aromatic hydrocarbon groups with polar functional groups, respectively. n represents an integer greater than or equal to 2 and less than 4, and n' represents an integer greater than or equal to 2 and less than 5. It should be noted that * indicates a connecting part.

[0024] In the above structural unit (A), R 1 They represent hydrogen atoms, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, polar functional groups, aliphatic hydrocarbon groups with polar functional groups, or aromatic hydrocarbon groups with polar functional groups, respectively.

[0025] The aliphatic hydrocarbon groups mentioned above are not particularly limited; examples include straight-chain, branched, or cyclic alkyl groups with 1 to 20 carbon atoms. The aromatic hydrocarbon groups mentioned above are not particularly limited; examples include substituted or unsubstituted aryl groups with 1 to 20 carbon atoms.

[0026] The polar functional groups mentioned above are not particularly limited; examples include amino, carboxyl, carbonyl, alkoxy, hydroxyl, nitrile, and nitro groups.

[0027] The aliphatic hydrocarbon group with polar functional group described above is not particularly limited. For example, a group obtained by substituting one or more hydrogen atoms in such an aliphatic hydrocarbon group with such a polar functional group can be used. The aromatic hydrocarbon group with polar functional group described above is also not particularly limited. For example, a group obtained by substituting one or more hydrogen atoms in such an aromatic hydrocarbon group with such a polar functional group can be used.

[0028] It should be noted that in the compounds of the present invention, a plurality of Rs are contained in one structural unit (A). 1 They can be the same or different. Furthermore, the multiple Rs contained in different structural units (A) 1 They can be the same or different.

[0029] In the above structural unit (A), n is an integer of 2 or more and 4 or less, and n' is not particularly limited as long as it is an integer of 2 or more and 5 or less. From the viewpoint of ease of obtaining raw materials, n and n' are preferably 2 or 3. From the viewpoint of being able to further improve the adhesive strength of the adhesive composition, especially for adhesives with low polarity, n and n' are more preferably 3.

[0030] More specifically, examples of the aforementioned structural unit (A) include structural units derived from dihydroxybenzene or its derivatives (when n and n' are 2) and structural units derived from trihydroxybenzene or its derivatives (when n and n' are 3). These structural units can be used individually or in combination of two or more.

[0031] The dihydroxybenzene or its derivatives are not particularly limited, and examples include resorcinol, catechol, hydroquinone, dihydroxytoluene, dihydroxyxylene, dihydroxyphenylethylamine hydrochloride, dihydroxybenzoic acid, dihydroxyphenylacetic acid, dihydroxyhydrogenated cinnamic acid, dihydroxyphenylpropionic acid, dihydroxyphenylalanine, dihydroxybenzaldehyde, dihydroxyacetophenone, diacetyldihydroxybenzene, dihydroxyphenyl-2-butanone, dihydroxyphenylacetic acid methyl ester, benzyldihydroxyphenyl ketone, dihydroxybenzamide, dihydroxymethoxybenzene, dihydroxybenzyl alcohol, dihydroxyphenyl ethanol, dihydroxyphenyl ethylene glycol, dihydroxyphenyl acetonitrile, and dihydroxynitrobenzene. These dihydroxybenzenes or their derivatives can be used alone or in combination of two or more. Among them, catechol is preferred due to its low steric hindrance and ease of interaction with the adhered material.

[0032] The aforementioned trihydroxybenzene or its derivatives are not particularly limited, and examples include pyrogallol, 1,2,4-trihydroxybenzene, resorcinol, trihydroxytoluene, trihydroxydiphenylmethane, 6-hydroxy-L-DOPA, gallic acid, methyl gallate, butyl gallate, isobutyl gallate, isoamyl gallate, hexadecyl gallate, stearyl gallate, trihydroxyacetophenone, trihydroxyphenylacetophenone, trihydroxyphenylbutanone, trihydroxybenzaldehyde, trihydroxybenzamide, and trihydroxynitrobenzene. These trihydroxybenzene or their derivatives can be used alone or in combination of two or more. Among them, pyrogallol is preferred from the perspective of less steric hindrance and easier interaction with the adhered material.

[0033] The aforementioned structural unit (A) may be composed solely of petroleum-derived materials, but it is preferable to include bio-derived materials. The depletion of petroleum resources and the carbon dioxide emissions resulting from the combustion of petroleum-derived products are considered problems. Therefore, efforts are being made to conserve petroleum resources by using bio-derived materials to replace petroleum-derived materials. If the aforementioned structural unit (A) includes bio-derived materials, it is preferable from the viewpoint of conserving petroleum resources. Furthermore, if the aforementioned structural unit (A) includes bio-derived materials, since bio-derived materials are originally generated by absorbing carbon dioxide from the atmosphere, it is considered that even if they are burned, the total amount of carbon dioxide in the atmosphere will not increase, which is also preferable from the viewpoint of reducing carbon dioxide emissions.

[0034] Examples of monomers constituting the aforementioned structural unit (A) containing biologically derived materials include resorcinol, dihydroxyphenylethylamine hydrochloride, dihydroxyhydrocinnamic acid, dihydroxyphenylalanine, dihydroxybenzaldehyde, dihydroxybenzyl alcohol, pyrogallol, 1,2,4-trihydroxybenzene, pyrogallol, 6-hydroxy-L-DOPA, gallic acid, methyl gallate, butyl gallate, isobutyl gallate, isoamyl gallate, hexadecyl gallate, stearyl gallate, trihydroxyacetophenone, trihydroxybenzaldehyde, trihydroxybenzamide, and trihydroxynitrobenzene.

[0035] The content of the above-mentioned structural unit (A) in the compound of the present invention is not particularly limited, but the preferred lower limit is 1 mol%, and the preferred upper limit is 60 mol%. If the content of the above-mentioned structural unit (A) is 1 mol% or more, the adhesive strength of the adhesive composition can be further improved by incorporating the compound into the adhesive composition, especially for adhesives with low polarity. If the content of the above-mentioned structural unit (A) is 60 mol% or less, the compound can have suitable physical properties required for use as a tackifying resin. The more preferred lower limit of the content of the above-mentioned structural unit (A) is 5 mol%, the more preferred upper limit is 50 mol%, the more preferred lower limit is 10 mol%, and the more preferred upper limit is 30 mol%.

[0036] The compounds of the present invention are not particularly limited to any compound having the above-described structural unit (A), but are preferably polymers having the above-described structural unit (A), and more preferably copolymers having the above-described structural unit (A) and other structural units. In the case of copolymers, the above-described structural unit (A) and other structural units can be copolymerized randomly, or they can be copolymerized regularly or periodically, for example, in the case where block segments are formed separately and then bonded to each other.

[0037] The compounds of the present invention preferably further contain an aliphatic hydrocarbon group with an unsaturated double bond. In this case, the compounds of the present invention may contain the aforementioned aliphatic hydrocarbon group with an unsaturated double bond in the above-described structural unit (A), or in other structural units. From the viewpoint of ease of synthesis and improving the compatibility of the compound with the base polymer, particularly with styrene-based elastomers, it is preferable to contain the aforementioned aliphatic hydrocarbon group with an unsaturated double bond in other structural units.

[0038] The other structural units mentioned above are not particularly limited, but are preferably structural units (B) derived from at least one monomer (b) selected from terpene monomers, vinyl monomers, and conjugated diene monomers. That is, the compounds of the present invention more preferably have structural units (B) derived from at least one monomer (b) selected from terpene monomers, vinyl monomers, and conjugated diene monomers, in addition to the aforementioned structural unit (A). By having the aforementioned structural unit (B), the compound can possess suitable physical properties required for use as a tackifying resin.

[0039] In this process, by incorporating compounds into the adhesive composition, the adhesive strength of the adhesive composition can be further improved. Therefore, structural units derived from terpene monomers or vinyl monomers are preferred, and a combination of structural units derived from terpene monomers and vinyl monomers is also preferred. Furthermore, from the viewpoint of improving the compatibility of the compound with the base polymer, particularly with styrene-based elastomers, structural units derived from terpene monomers or conjugated diene monomers are preferred. These structural units have aliphatic hydrocarbon groups containing the aforementioned unsaturated double bonds. Therefore, by incorporating these structural units into the compound, the compatibility of the compound with the base polymer, particularly with styrene-based elastomers, is improved, thereby suppressing the decrease in adhesive strength of the adhesive composition caused by deterioration in compatibility.

[0040] The aforementioned terpene monomers are not particularly limited, and examples include α-pinene, β-pinene, limonene, dipentene, δ-3-carene, dimethylocttriene, allocimene, myrcene, ocimene, linalool, and cosmos terpenes. Among these, α-pinene, β-pinene, or limonene are preferred because incorporating these compounds into the adhesive composition can further improve the adhesive strength of the composition.

[0041] The aforementioned vinyl monomers are not particularly limited. From the viewpoint of improving the compatibility of the compound with the base polymer, especially with acrylic polymers, vinyl monomers that do not have a structure containing two or more aromatic rings in one molecule (e.g., naphthalene, anthracene, biphenyl, anthraquinone, benzophenone, etc.) are preferred. Examples of vinyl monomers that do not have a structure containing two or more aromatic rings in one molecule include ethylene, propylene, butene, hexene, vinyl acetate, vinyl chloride, styrene, α-methylstyrene, coumarone, indene, vinyltoluene, divinylbenzene, divinyltoluene, 2-phenyl-2-butene, etc. Among these, styrene is preferred from the viewpoint that the adhesive strength of the adhesive composition can be further improved by incorporating the compound into the adhesive composition.

[0042] The aforementioned conjugated diene monomers are not particularly limited; examples include butadiene, isoprene, isoprene, and cyclopentadiene. Among these, isoprene is preferred because incorporating compounds into the adhesive composition can further improve the adhesive strength of the composition.

[0043] These monomers (b) can be used alone or in combination of two or more.

[0044] The aforementioned structural unit (B) may be composed solely of petroleum-derived materials, but it is preferable to include bio-derived materials. The depletion of petroleum resources and the carbon dioxide emissions resulting from the combustion of petroleum-derived products are considered problems. Therefore, efforts are being made to conserve petroleum resources by using bio-derived materials to replace petroleum-derived materials. If the aforementioned structural unit (B) includes bio-derived materials, it is preferable from the viewpoint of conserving petroleum resources. Furthermore, if the aforementioned structural unit (B) includes bio-derived materials, since bio-derived materials are originally generated by absorbing carbon dioxide from the atmosphere, it is considered that even if they are burned, the total amount of carbon dioxide in the atmosphere will not increase, which is also preferable from the viewpoint of reducing carbon dioxide emissions.

[0045] Examples of monomers (b) constituting the aforementioned structural unit (B) comprising biologically derived materials include terpene monomers, ethylene, propylene, hexene, butadiene, isoprene, etc.

[0046] The content of the structural unit (B) in the compound of the present invention is not particularly limited, but a preferred lower limit is 40 mol%, and a preferred upper limit is 99 mol%. If the content of the structural unit (B) is 40 mol% or more, the compound can possess suitable physical properties required for use as a tackifying resin. If the content of the structural unit (B) is 99 mol% or less, the content of the structural unit (A) can be sufficiently ensured, and therefore, by incorporating the compound into the adhesive composition, the adhesive strength of the adhesive composition can be further improved, especially for adhesives with low polarity. A more preferred lower limit for the content of the structural unit (B) is 50 mol%, and a more preferred upper limit is 90 mol%.

[0047] When the compound of the present invention has the above-described structural unit (A) and the above-described structural unit (B), it is preferably a copolymer having the structure shown in the following formula.

[0048] The copolymer having such a structure is a copolymer obtained by using a cationic polymerization method as described later, which can further improve the adhesive strength of the adhesive composition, especially for low polarity substrates.

[0049]

Chemical Formula 3

[0050]

[0051] In the formula, A represents structural unit (A), B represents structural unit (B), and s and t represent integers greater than or equal to 1. It should be noted that * indicates a connecting part.

[0052] In addition, other structural units mentioned above may include structural units derived from other phenolic monomers or structural units derived from maleic anhydride that are not included in structural unit (A).

[0053] The other phenolic monomers mentioned above are not particularly limited, and examples include phenol, cresol, xylenol, propionic acid, nonylphenol, methoxyphenol, bromophenol, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. These other phenolic monomers can be used alone or in combination of two or more.

[0054] The molecular weight of the compounds of the present invention is not particularly limited, but the preferred lower limit for the weight-average molecular weight (Mw) is 400, and the preferred upper limit is 10,000. If the weight-average molecular weight (Mw) is within the above range, the compound can have the suitable physical properties required for use as a tackifying resin. The more preferred lower limit for the weight-average molecular weight (Mw) is 500, the more preferred upper limit is 5,000, the further preferred lower limit is 700, and the further preferred upper limit is 3,000.

[0055] To adjust the weight-average molecular weight (Mw) to the range described above, one can simply adjust the composition of the compound, the polymerization method, the polymerization conditions, etc.

[0056] It should be noted that the weight-average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) as described later can be determined by the following methods.

[0057] The compound solution was filtered using a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The resulting filtrate was fed into a gel permeation chromatograph (e.g., Waters 2690 Separations Model) and GPC was performed at a sample flow rate of 1 mL / min and a column temperature of 40 °C to determine the polystyrene-converted molecular weight of the compound, and to calculate the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn). A column, for example, a GPC KF-802.5L (Showa Denko) was used, and a differential refractometer was used as the detector.

[0058] The Young's modulus of the compounds of the present invention is not particularly limited, but the preferred lower limit of the Young's modulus at 25°C is 10 MPa. If the Young's modulus at 25°C is 10 MPa or higher, the compound has moderate hardness and, rather than being an adhesive, possesses suitable physical properties for use as a tackifying resin. A more preferred lower limit of the Young's modulus at 25°C is 50 MPa, and a further preferred lower limit is 70 MPa.

[0059] There is no particular upper limit to the Young's modulus at 25°C. From the viewpoint of preventing the adhesive composition containing the compound from becoming too hard and reducing the adhesive strength, the preferred upper limit is 10,000 MPa, and the more preferred upper limit is 5,000 MPa.

[0060] To adjust the Young's modulus at 25°C to the range described above, one can adjust the molecular weight of the compound, the composition and content of the structural units (A) and (B) described above in the compound, for example.

[0061] It should be noted that the Young's modulus at 25°C can be determined using a tensile testing apparatus (e.g., ORIENTEC, TENSILON) at a tensile speed of 200 mm / min, a clamping distance of 15 mm, and a temperature of 25°C. The test sample can be prepared, for example, by filling the compound into a 10 × 50 mm mold and melting it at a temperature 100°C higher than the glass transition temperature to create a 1 mm thick test piece.

[0062] The glass transition temperature of the compounds of the present invention is not particularly limited, but a preferred lower limit is 0°C and a preferred upper limit is 200°C. If the glass transition temperature is within the above range, the compound can easily have its Young's modulus adjusted to the above range, and can have the suitable physical properties required for use as a tackifying resin. A more preferred lower limit of the above glass transition temperature is 10°C, and a more preferred upper limit is 150°C.

[0063] It should be noted that the glass transition temperature can be measured using a differential scanning calorimeter (e.g., Hitachi High-Tech Science, SII Exstar 6000 / DSC 6220) under a nitrogen atmosphere and at a heating rate of 10 °C / min, with the value obtained as the first run.

[0064] The iodine value of the compounds of the present invention is not particularly limited, but a preferred lower limit is 2 g / 100 g, and a preferred upper limit is 180 g / 100 g. If the iodine value is 2 g / 100 g or higher, the adhesive strength of the adhesive composition can be suppressed due to the deterioration of the compatibility between the compound and the base polymer, particularly with the compatibility between the compound and styrene-based elastomers. If the iodine value is 180 g / 100 g or lower, the adhesive strength of the adhesive composition can be further improved by incorporating the compound into the adhesive composition, particularly for adhesives with low polarity. A more preferred lower limit for the iodine value is 70 g / 100 g, and a more preferred upper limit is 170 g / 100 g.

[0065] It should be noted that the iodine value is an indicator of the amount of unsaturated double bonds (C=C bond amount), and refers to the value measured according to the method described in "JIS K0070:1992".

[0066] The percentage of biologically derived carbon (carbon atoms) in the compounds of this invention is not particularly limited, but the percentage of biologically derived carbon in the total carbon is preferably 10% or more. A percentage of biologically derived carbon of 10% or more serves as a benchmark for "bio-based products".

[0067] If the carbon content derived from biological sources is 10% or more, it is preferred from the perspective of conserving petroleum resources and reducing carbon dioxide emissions. A more preferred lower limit for the carbon content derived from biological sources is 30%, a further preferred lower limit is 60%, an even more preferred lower limit is 70%, and an even more preferred lower limit is 90%. There is no particular limitation on the upper limit for the carbon content derived from biological sources; it can be 100%.

[0068] It should be noted that carbon derived from biological sources contains a certain proportion of the radioactive isotope (C-14), while carbon derived from petroleum contains almost no C-14. Therefore, the carbon content from biological sources can be calculated by measuring the C-14 concentration in the compound. Specifically, this can be done according to the standard ASTM D6866-20, which is used in many bioplastics industries.

[0069] The compounds of the present invention also include hydrides of the above-mentioned compounds. It should be noted that a hydride refers to a compound obtained by hydrogenation to saturate the carbon-carbon double bonds present in such compounds. Even such hydrides are suitable for use as tackifying resins in adhesive compositions, improving the adhesive strength of the adhesive composition, particularly for low-polarity substrates.

[0070] The method for manufacturing the compounds of the present invention is not particularly limited, but the following method is preferred, for example: a method for manufacturing a compound having at least one structural unit (A) selected from structural units (A-1) and (A-1') shown in the following formula, and a structural unit (B) derived from at least one monomer (b) selected from terpene monomers, vinyl monomers, and conjugated diene monomers; or a method for copolymerizing the monomer (a) shown in the following formula with the aforementioned monomer (b). Such a method for manufacturing the compound is also part of the present invention.

[0071] [Chemical Formula 4]

[0072]

[0073] [Chemical Formula 5]

[0074]

[0075] In the formula, R 1 These represent hydrogen atoms, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, polar functional groups, aliphatic hydrocarbon groups with polar functional groups, or aromatic hydrocarbon groups with polar functional groups, respectively. n represents an integer greater than or equal to 2 and less than 4, n' represents an integer greater than or equal to 2 and less than 5, and n” represents an integer greater than or equal to 2 and less than 5. It should be noted that * represents a connecting part.

[0076] The above-mentioned n” is preferably 2 or 3, more preferably 3.

[0077] In the method for manufacturing the compound of the present invention, it is preferable to copolymerize the monomer (a) and the monomer (b) by cationic polymerization.

[0078] By using cationic polymerization, monomer (a) and monomer (b) can be copolymerized without prior chemical modification to protect the phenolic hydroxyl groups of monomer (a), and without subsequent deprotection. Therefore, the copolymerization of monomer (a) and monomer (b) can be achieved through a simpler one-stage reaction process, which also contributes to the reduction of impurities and the improvement of yield.

[0079] As a method for copolymerizing the monomer (a) and monomer (b) by cationic polymerization, a preferred method is to react the monomer (a) and monomer (b) in the presence of a Lewis acid. According to this method, a cation of monomer (b) is generated, cationic polymerization of the monomers (b) is carried out, and Fridel-Crafts alkylation of the monomers (a) and (b) is performed. By repeatedly performing this reaction, a copolymer having structural units (A) from monomer (a) and structural units (B) from monomer (b) can be obtained.

[0080] The Lewis acid mentioned above is not particularly limited, and conventionally known Lewis acids can be used, such as aluminum chloride (AlCl3), diethylaluminum chloride (Et2AlCl2), tin(IV) chloride (SnCl4), titanium(IV) chloride (TiCl4), boron trichloride (BCl3), boron trifluoride ether complex (BF3·EtO), etc. Among these, aluminum chloride (AlCl3) is preferred from the perspective of obtaining higher yields.

[0081] More specifically, for example, if pyrogallol is used as the monomer mentioned above (a), α-pinene is used as the monomer mentioned above (b), and they are reacted in the presence of aluminum chloride (AlCl3) as a Lewis acid, the reaction shown in the following scheme is considered to be carried out.

[0082] That is, a cation of α-pinene, which is monomer (b) above, is generated, and cationic polymerization of α-pinenes with each other is carried out (upper section of the following scheme), and a Fridel-Crafts alkylation reaction of pyrogallol, which is monomer (a) above, and α-pinene, which is monomer (b) above, is carried out (middle section of the following scheme). By repeating such a reaction, a copolymer having structural units from pyrogallol and structural units from α-pinene can be obtained (lower section of the following scheme). It should be noted that such a copolymer has structural units from pyrogallol in the main chain backbone or at the end of the main chain backbone.

[0083]

Chemical Formula 6

[0084]

[0085] In the formula, s and t represent integers greater than or equal to 1. It should be noted that * denotes a connecting part.

[0086] The compounds of the present invention are suitable for use as tackifying resins in adhesive compositions. Adhesive compositions containing a base polymer and the compound (T1) of the present invention are also part of this invention.

[0087] The content of the compound (T1) of the present invention in the adhesive composition is not particularly limited. Even a small amount compared to conventional tackifying resins can improve the adhesive strength of the adhesive composition. The preferred lower limit is 1 part by weight relative to 100 parts by weight of the base polymer, and the preferred upper limit is 35 parts by weight. If the content of the compound (T1) of the present invention is 1 part by weight or more, the adhesive strength of the adhesive composition can be further improved, especially for adhesives with low polarity. If the content of the compound (T1) of the present invention is 35 parts by weight or less, the adhesive composition can be prevented from becoming too hard and reducing the adhesive strength. The more preferred lower limit of the content of the compound (T1) of the present invention is 3 parts by weight, the more preferred upper limit is 30 parts by weight, the more preferred lower limit is 5 parts by weight, and the more preferred upper limit is 20 parts by weight.

[0088] The adhesive composition of the present invention may further contain at least one tackifying resin (T2) selected from rosin ester resins, terpene resins, and petroleum resins. Among these, rosin ester resins or terpene resins are preferred from the viewpoint of being able to further improve the adhesive strength of the adhesive composition.

[0089] The preferred lower limit of the softening temperature of the aforementioned tackifying resin (T2) is 70°C, and the preferred upper limit is 170°C. If the softening temperature is 70°C or higher, it is possible to prevent the adhesive composition from becoming too soft and thus reducing the bond strength. If the softening temperature is 170°C or lower, the wettability of the interface of the adhesive layer formed by the adhesive composition is improved, and interfacial delamination is suppressed. A more preferred lower limit of the softening temperature is 120°C.

[0090] It should be noted that the softening temperature refers to the softening temperature determined by the JIS K2207 ring and ball method.

[0091] The preferred lower limit of the hydroxyl value of the aforementioned tackifying resin (T2) is 25, and the preferred upper limit is 150. By keeping the hydroxyl value within the aforementioned range, the wettability of the interface of the adhesive layer formed by the adhesive composition is improved, thereby suppressing interfacial peeling. The more preferred lower limit of the aforementioned hydroxyl value is 30, and the more preferred upper limit is 130.

[0092] It should be noted that the hydroxyl value can be determined using JIS K1557 (phthalic anhydride method).

[0093] The content of the aforementioned tackifying resin (T2) is not particularly limited, but the preferred lower limit is 10 parts by weight relative to 100 parts by weight of the base polymer, and the preferred upper limit is 100 parts by weight. If the content of the aforementioned tackifying resin (T2) is 10 parts by weight or more, the adhesive strength of the adhesive composition can be further improved. If the content of the aforementioned tackifying resin (T2) is 100 parts by weight or less, the adhesive composition can be prevented from becoming too hard and reducing its adhesive strength. A more preferred lower limit for the content of the aforementioned tackifying resin (T2) is 15 parts by weight, a more preferred upper limit is 60 parts by weight, a further preferred upper limit is 50 parts by weight, and an even more preferred upper limit is 40 parts by weight.

[0094] The aforementioned base polymers are not particularly limited, and examples include acrylic polymers, rubber polymers, urethane polymers, and silicone polymers. Among these, acrylic polymers are preferred due to their relative stability against light, heat, and moisture. Furthermore, rubber polymers are also preferred due to their low selectivity for adherends, ability to bond with various adherends, and resistance to peeling from adherends even when immersed in alkaline solutions. Of the aforementioned rubber polymers, block copolymers having blocks derived from styrene monomers and blocks derived from conjugated diene monomers, or hydrogenated versions thereof, are more preferably styrene-based elastomers.

[0095] From the viewpoint that the adhesion becomes better at low temperatures due to the improved initial adhesion, the above-mentioned acrylic polymer preferably has at least one structural unit selected from alkyl (meth)acrylates with 1 to 12 carbon atoms and alkyl (meth)acrylates with 13 to 18 carbon atoms.

[0096] Alkyl methacrylates having 1 to 12 carbon atoms as the alkyl group include, for example, 2-ethylhexyl methacrylate, butyl methacrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, and isopropyl methacrylate. Alkyl methacrylates having 13 to 18 carbon atoms as the alkyl group include, for example, tridecyl methacrylate and stearyl methacrylate. Among these, 2-ethylhexyl methacrylate or butyl methacrylate is preferred because the acrylic polymer exhibits high adhesive strength.

[0097] The content of at least one structural unit selected from alkyl (meth)acrylates with 1 to 12 carbon atoms and alkyl (meth)acrylates with 13 to 18 carbon atoms in the above-mentioned acrylic polymer is not particularly limited. The preferred lower limit of the above content is 10% by weight, the preferred upper limit is 100% by weight, the more preferred lower limit is 30% by weight, the more preferred upper limit is 95% by weight, the even more preferred lower limit is 50% by weight, and the even more preferred upper limit is 90% by weight. By setting the above content within such ranges, the above-mentioned acrylic polymer can exhibit high adhesive strength.

[0098] The aforementioned acrylic polymers preferably have structural units derived from monomers with crosslinking functional groups.

[0099] By incorporating structural units derived from monomers possessing crosslinking functional groups into the aforementioned acrylic polymer, and by adding a crosslinking agent, a crosslinked structure of the acrylic polymer is formed in the adhesive layer formed from the adhesive composition. This results in increased gel content and bulk strength of the adhesive layer, and improved adhesive strength. The crosslinking functional groups are not particularly limited, and examples include amino, carboxyl, carbonyl, hydroxyl, epoxy, and isocyanate groups.

[0100] Examples of monomers having crosslinking functional groups include, specifically, hydroxyalkyl (meth)acrylate, glyceryl dimethacrylate, glycidyl (meth)acrylate, 2-methacryloyloxyethyl isocyanate, (meth)acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, and fumaric acid. More specifically, examples of hydroxyalkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate. These monomers having crosslinking functional groups can be used alone or in combination of two or more. From the viewpoint of improving the gel content of the adhesive layer formed from the adhesive composition and the strength of the bulk, monomers having hydroxyl groups, such as hydroxyalkyl (meth)acrylate and glyceryl dimethacrylate, or monomers having carboxyl groups, such as (meth)acrylic acid, are preferred.

[0101] The content of structural units derived from the monomers having cross-linking functional groups in the aforementioned acrylic polymers is not particularly limited, but a preferred lower limit is 0.01% by weight, and a preferred upper limit is 20% by weight. By setting the content of the structural units derived from the monomers having cross-linking functional groups within this range, the gel fraction and bulk strength of the adhesive layer formed by the adhesive composition are increased, thereby improving the adhesive strength. A more preferred lower limit of the content of the structural units derived from the monomers having cross-linking functional groups is 0.05% by weight, and a more preferred upper limit is 5% by weight.

[0102] The aforementioned acrylic polymers may, as needed, also include structural units derived from other copolymerizable monomers besides structural units derived from alkyl (meth)acrylates as described above and structural units derived from monomers with crosslinking functional groups as described above.

[0103] To obtain the aforementioned acrylic polymer, the mixture of monomers described above is subjected to a free radical reaction in the presence of a polymerization initiator. As a method for subjecting the monomer mixture to a free radical reaction, i.e., a polymerization method, conventionally known methods can be used, such as solution polymerization (boiling point polymerization or isothermal polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, etc.

[0104] The weight-average molecular weight (Mw) of the aforementioned acrylic polymers is not particularly limited, but a preferred lower limit is 200,000, and a preferred upper limit is 2,000,000. If the weight-average molecular weight (Mw) is 200,000 or higher, the bulk strength of the adhesive layer formed by the adhesive composition is increased, and the adhesive strength is improved. If the weight-average molecular weight (Mw) is 2,000,000 or lower, the wettability of the interface of the adhesive layer formed by the adhesive composition is improved, and interfacial delamination can be suppressed. A more preferred lower limit for the weight-average molecular weight (Mw) is 400,000, and a more preferred upper limit is 1,500,000.

[0105] The ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the aforementioned acrylic polymers (molecular weight distribution, Mw / Mn) is not particularly limited, but a preferred lower limit is 1.05, and a preferred upper limit is 5.0. If Mw / Mn is below 5.0, the proportion of low-molecular-weight components can be suppressed, the bulk strength of the adhesive layer formed by the adhesive composition is improved, and the adhesive strength is increased. A more preferred upper limit for Mw / Mn is 4.5, a further preferred upper limit is 4, and an even more preferred upper limit is 3.5.

[0106] To adjust the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) to the ranges described above, one can adjust the composition, polymerization method, polymerization conditions, etc. of the acrylic polymer.

[0107] The aforementioned styrene-based elastomers are simply block copolymers that exhibit rubber elasticity at room temperature and possess both hard and soft segments. It should be noted that the blocks derived from styrene monomers are hard segments, while the blocks derived from conjugated diene monomers are soft segments.

[0108] The aforementioned styrene monomers are not particularly limited, and examples include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyl dimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, vinylxylene, vinylnaphthalene, vinylpyridine, diphenylethylene, and diphenylethylene containing a tert-amino group. The aforementioned diphenylethylene containing a tert-amino group is not particularly limited, and examples include 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene. These styrene monomers can be used alone or in combination of two or more.

[0109] The aforementioned conjugated diene monomers are not particularly limited; examples include isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, and 2-chloro-1,3-butadiene. These conjugated diene monomers can be used alone or in combination of two or more.

[0110] Specifically, examples of styrene-isoprene-styrene (SIS) block copolymers, styrene-butadiene-styrene (SBS) block copolymers, and styrene-chloroprene-styrene block copolymers include styrene-isoprene-styrene block copolymers. Among these, SIS block copolymers and SBS block copolymers are preferred, with SIS block copolymers being more preferred because they readily exhibit high adhesive strength and are not easily peeled off from the adherends even when impregnated with alkaline solutions. These styrene-based elastomers can be used alone or in combination of two or more.

[0111] In addition to triblock copolymers containing blocks from the styrene monomers and blocks from the conjugated diene monomers, the aforementioned styrene-based elastomers may also contain diblock copolymers containing blocks from the styrene monomers and blocks from the conjugated diene monomers.

[0112] The content of the diblock copolymer in the aforementioned styrene-based elastomer (hereinafter also referred to as the "diblock ratio") is not particularly limited, but a preferred lower limit is 50% by weight, and a more preferred lower limit is 70% by weight. If the diblock ratio is within the above range, the adhesive composition exhibits higher adhesion to the adherends and improved bond strength. The upper limit of the diblock ratio is not particularly limited, but from the viewpoint of maintaining the cohesive strength of the adhesive composition, a preferred upper limit is 90% by weight.

[0113] It should be noted that the diblock ratio can be calculated based on the peak area ratio of each copolymer as determined by gel permeation chromatography (GPC).

[0114] The content of blocks derived from the styrene monomers in the aforementioned styrene-based elastomers (hereinafter also referred to as "styrene content") is not particularly limited, but a preferred upper limit is 20% by weight, and a more preferred upper limit is 16% by weight. If the styrene content is within the above range, the adhesive composition will not become too rigid, the adhesion of the adhered objects will be improved, and the bond strength will be increased. The lower limit of the aforementioned styrene content is not particularly limited, but from the viewpoint of maintaining the cohesive strength of the adhesive composition, a preferred lower limit is 8% by weight.

[0115] It should be noted that the styrene content can be adjusted according to... 1 The peak area ratio of each block was calculated by H-NMR.

[0116] The weight-average molecular weight of the aforementioned styrene-based elastomer is not particularly limited, but a preferred lower limit is 50,000, and a preferred upper limit is 600,000. If the weight-average molecular weight is 50,000 or higher, the bulk strength of the adhesive layer formed by the adhesive composition is increased, and the adhesive strength is improved. If the weight-average molecular weight is 600,000 or lower, it is possible to prevent excessive reduction in the compatibility of the aforementioned styrene-based elastomer with other components. A more preferred lower limit for the aforementioned weight-average molecular weight is 100,000, and a more preferred upper limit is 500,000.

[0117] When the base polymer is the acrylic polymer described above, the adhesive composition of the present invention preferably contains a crosslinking agent.

[0118] By adjusting the type and amount of the crosslinking agent, the gel content of the adhesive layer formed by the adhesive composition can be easily adjusted. The crosslinking agent is not particularly limited; examples include isocyanate-based crosslinking agents, aziridine-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-type crosslinking agents. Isocyanate-based crosslinking agents are preferred.

[0119] The preferred lower limit of the content of the crosslinking agent relative to 100 parts by weight of the acrylic polymer is 0.01 parts by weight, the preferred upper limit is 10 parts by weight, the more preferred lower limit is 0.1 parts by weight, and the more preferred upper limit is 5 parts by weight.

[0120] For the purpose of improving adhesive strength, the adhesive composition of the present invention may contain a silane coupling agent. The silane coupling agent is not particularly limited, and examples include epoxy silanes, acrylic silanes, methacrylic silanes, amino silanes, isocyanate silanes, etc.

[0121] For the purpose of providing light-blocking properties, the adhesive composition of the present invention may contain a colorant. The colorant is not particularly limited, and examples include carbon black, aniline black, and titanium dioxide. Among these, carbon black is preferred from the perspective of being relatively inexpensive and chemically stable.

[0122] The adhesive composition of the present invention may contain, as needed, conventionally known microparticles and additives such as inorganic microparticles, conductive microparticles, antioxidants, foaming agents, organic fillers, and inorganic fillers.

[0123] An adhesive tape having an adhesive layer containing the adhesive composition of the present invention is also one of the present inventions.

[0124] When the base polymer is the aforementioned acrylic polymer, the gel fraction of the adhesive layer is not particularly limited, but a preferred lower limit is 10% by weight, and a preferred upper limit is 70% by weight. If the gel fraction is 10% by weight or more, the bulk strength of the adhesive layer and the adhesive strength are improved. If the gel fraction is 70% by weight or less, the interfacial wettability of the adhesive layer is improved, and interfacial peeling can be suppressed. A more preferred lower limit of the gel fraction is 15% by weight, a more preferred upper limit is 60% by weight, a further preferred lower limit is 20% by weight, and a further preferred upper limit is 50% by weight.

[0125] The gel fraction of the adhesive layer can be adjusted to the range described above, for example, by adjusting the composition of the acrylic polymer, the weight-average molecular weight, and the type and amount of the crosslinking agent.

[0126] It should be noted that the gel fraction of the adhesive layer can be determined by the following method.

[0127] The adhesive tape was cut into 50mm × 100mm flat rectangles to prepare test pieces. The test pieces were immersed in ethyl acetate at 23°C for 24 hours, then removed from the ethyl acetate and dried at 110°C for 1 hour. The weight of the dried test pieces was measured, and the gel fraction was calculated using the following formula (1). It should be noted that no release film for protecting the adhesive layer was laminated on the test pieces.

[0128] Gel fraction (wt%) = 100 × (W2 - W0) / (W1 - W0) (1)

[0129] (W0: Weight of the substrate, W1: Weight of the test piece before impregnation, W2: Weight of the test piece after impregnation and drying)

[0130] When the base polymer is the aforementioned acrylic polymer, the preferred lower limit for the shear storage modulus (hereinafter referred to as "shear storage modulus") of the adhesive layer at 25°C, measured using a dynamic viscoelasticity measuring device at a frequency of 10 Hz, is 1.0 × 10⁻⁶. 4 Pa, preferably with an upper limit of 5.0 × 10 5 Pa.

[0131] If the shear storage modulus of the adhesive layer is within the aforementioned range, the adhesive strength of the adhesive layer is further improved. More preferably, the shear storage modulus of the adhesive layer is 3.0 × 10⁻⁶. 4 Pa or higher, more preferably 5.0 × 10 Pa. 4 Pa or higher, more preferably 4.0 × 10 Pa. 5 Pa below, more preferably 3.5 × 10 Pa 5 Below Pa. The shear storage modulus of the above-mentioned adhesive layer can be adjusted by the type and polymerization ratio of the monomers constituting the above-mentioned base polymer, the molecular weight of the above-mentioned base polymer, the gel fraction of the above-mentioned adhesive layer, the presence or absence of the above-mentioned tackifying resin (T2), the type and content of the compound (T1) of the present invention and the above-mentioned tackifying resin (T2), etc.

[0132] It should be noted that the shear storage modulus of the adhesive layer can be determined using the following method.

[0133] First, a test sample consisting solely of an adhesive layer is prepared. For the obtained test sample, a dynamic viscoelasticity measurement device, such as an IT Measurement & Control Corporation DVA-200 or equivalent, is used to measure the dynamic viscoelastic spectrum from -50°C to 200°C under low-rate heating shear deformation mode at 5°C / min and a measurement frequency of 10Hz. The storage modulus at 25°C under these conditions is then determined.

[0134] When the base polymer is the acrylic polymer, the adhesive layer preferably has a peak at -20°C and below 20°C when the loss tangent (tanδ, hereinafter referred to as "loss tangent") is measured at a frequency of 10 Hz using a dynamic viscoelasticity measuring device.

[0135] By ensuring that the loss tangent of the adhesive layer peaks within the aforementioned range, it is easier to balance the adhesive strength and holding power of the adhesive layer. More preferably, the loss tangent peaks below 15°C, and even more preferably below 12°C. More preferably, the loss tangent peaks above -15°C, and even more preferably above -10°C.

[0136] It should be noted that the loss tangent of the adhesive layer can be obtained by measuring the dynamic viscoelastic spectrum from -100℃ to 200℃ using a viscoelastic spectrometer (e.g., IT Measurement & Control Co., Ltd., DVA-200, or equivalent) under conditions of 5℃ / min in low-speed heating shear deformation mode and a measurement frequency of 10Hz.

[0137] The thickness of the adhesive layer is not particularly limited, but the preferred lower limit is 20 μm, the preferred upper limit is 100 μm, the more preferred lower limit is 25 μm, and the more preferred upper limit is 80 μm. If the thickness of the adhesive layer is within this range, the adhesive layer can have sufficient adhesive strength.

[0138] It should be noted that the thickness of the adhesive layer can be measured using a dial thickness gauge (such as the "ABS digital indicator" manufactured by Mitutoyo).

[0139] The adhesive tape of the present invention may have a substrate. In this case, the adhesive layer may be laminated on one side of the substrate or on both sides of the substrate.

[0140] The aforementioned substrate is not particularly limited; examples include resin films. The aforementioned resin film is not particularly limited; examples include polyolefin resin films such as polyethylene film and polypropylene film, polyester resin films such as polyethylene terephthalate (PET) film, ethylene-vinyl acetate copolymer films, polyvinyl chloride resin films, and polyurethane resin films. Furthermore, as the aforementioned substrate, examples include polyolefin foam sheets such as polyethylene foam sheets and polypropylene foam sheets, and polyurethane foam sheets. Among these, PET film is preferred.

[0141] The thickness of the substrate is not particularly limited, but the preferred lower limit is 5 μm, the preferred upper limit is 30 μm, the more preferred lower limit is 8 μm, and the more preferred upper limit is 20 μm.

[0142] The adhesive tape of the present invention may have other layers besides the adhesive layer and the substrate described above, as needed.

[0143] The method for manufacturing the adhesive tape of the present invention is not particularly limited. For example, when the adhesive layer is laminated on both sides of the substrate, the following method can be used.

[0144] First, a solution of adhesive composition A is prepared by adding a solvent to a base polymer, the compound of the present invention (T1), a tackifying resin (T2), a crosslinking agent, etc. This solution of adhesive composition A is then applied to the surface of a substrate, and the solvent in the solution is completely dried to form adhesive layer A. Next, a release film is overlapped onto the formed adhesive layer A with its release surface facing the adhesive layer A.

[0145] Next, a release film different from the aforementioned release film is prepared. A solution of adhesive composition B is applied to the release treatment surface of this release film, and the solvent in the solution is completely dried and removed, thereby creating a laminated film with adhesive layer B formed on the surface of the release film. The resulting laminated film is overlapped onto the back side of the substrate with adhesive layer B facing each other, to create a laminated body. Then, the laminated body is pressed using a rubber roller or the like. As a result, a double-sided adhesive tape with adhesive layers on both sides of the substrate and the surfaces of the adhesive layers covered by the release film can be obtained.

[0146] Alternatively, two sets of laminated films can be made using the same method. These laminated films are then overlapped on both sides of the substrate with the adhesive layer of the laminated film facing the substrate to create a laminate. The laminate is then pressed using a rubber roller or similar device. This results in a double-sided adhesive tape with adhesive layers on both sides of the substrate, and the surfaces of the adhesive layers are covered by a release film.

[0147] The adhesive composition and adhesive tape of the present invention are not particularly limited in their applications. Due to their high adhesive strength, especially for adhesives with low polarity (such as those difficult to bond, such as those formed from polyolefin resins or fluoropolymers), they are suitable for applications such as fixing electronic device components or automotive components. More specifically, they are suitable for fixing components in televisions, monitors, portable electronic devices, automotive electronic devices, etc.

[0148] The shape of the adhesive tape of the present invention is not particularly limited in these applications; for example, it can be square, rectangular, frame-shaped, circular, oval, ring-shaped, etc.

[0149] Invention Effects

[0150] According to the present invention, a compound capable of improving the adhesive strength of an adhesive composition, particularly for substrates with low polarity, can be provided. Furthermore, according to the present invention, a method for manufacturing the compound, an adhesive composition containing the compound, and an adhesive tape having an adhesive layer containing the adhesive composition can be provided. Detailed Implementation

[0151] The present invention will be described in more detail below with examples, but the present invention is not limited to these examples.

[0152] (Synthesis example 1)

[0153] (Preparation of acrylic polymers)

[0154] 100 parts by weight of ethyl acetate were added to a reactor equipped with a thermometer, stirrer, and condenser. After nitrogen replacement, the reactor was heated to initiate reflux. After the ethyl acetate boiled, 0.08 parts by weight of azobisisobutyronitrile (AIBN) as a polymerization initiator was added 30 minutes later. The monomer mixture shown in Table 1 was added dropwise uniformly and slowly over 1 hour and 30 minutes to allow the reaction to proceed. 30 minutes after the addition was completed, 0.1 parts by weight of AIBN was added, and the polymerization reaction was further carried out for 5 hours. Ethyl acetate was added to the reactor to dilute and cool it, thus obtaining a solution of acrylic polymer with a solid content of 25% by weight.

[0155] The obtained acrylic polymer solution was filtered using a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The filtrate was fed into a gel permeation chromatograph (Waters Corporation, 2690 Separations Model) and GPC was performed at a sample flow rate of 1 mL / min and a column temperature of 40 °C to determine the polystyrene-converted molecular weight of the acrylic polymer, and to calculate the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn). A GPC KF-806L column (Showa Denko Corporation) was used as the column, and a differential refractometer was used as the detector.

[0156] (Synthesis example 2)

[0157] (Preparation of acrylic polymers)

[0158] The amount of ethyl acetate added was changed to 50 parts by weight, and otherwise the same procedure was followed as in Synthesis Example 1 to obtain an acrylic polymer.

[0159] (Synthesis example 3)

[0160] (Preparation of acrylic polymers)

[0161] Except for changing the monomer mixture as shown in Table 1, the same procedure as in Synthesis Example 1 was followed to obtain an acrylic polymer.

[0162] Table 1

[0163]

[0164] (Synthesis Example A)

[0165] (Preparation of compound (T1))

[0166] In a reactor equipped with a thermometer, stirrer, and condenser, 50 parts by weight of toluene were added and nitrogen purged. The reactor was then heated to initiate reflux. After 30 minutes, while maintaining the toluene at 75°C, 2 parts by weight of aluminum chloride (AlCl3) were added. A solution obtained by dissolving 22.3 parts by weight of monomer (a) and 27.7 parts by weight of monomer (b) (molar ratios shown in Table 2) in 50 parts by weight of toluene was slowly added dropwise over 1 hour and 30 minutes to allow the reaction to proceed. After 4 hours of polymerization, 0.1 parts by weight of pyridine was added to the reactor while cooling, thereby neutralizing the hydrochloric acid produced by the aluminum chloride (AlCl3). The precipitate formed by neutralization was filtered, and the resulting filtrate was separated. The toluene was then evaporated to obtain a solid compound (T1).

[0167] The obtained compound (T1) was subjected to l H-NMR analysis confirmed that compound (T1) is a copolymer having structural units (A) derived from catechol as monomer (a) and structural units (B) derived from α-pinene as monomer (b).

[0168] The obtained compound (T1) was dissolved in tetrahydrofuran to obtain a solution, which was then filtered using a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The filtrate was fed into a gel permeation chromatograph (Waters Corporation, 2690 Separations Model) and GPC was performed at a sample flow rate of 1 mL / min and a column temperature of 40 °C to determine the polystyrene-converted molecular weight of compound (T1) and calculate the weight-average molecular weight (Mw). A GPC KF-802.5L column (Showa Denko Corporation) was used as the column, and a differential refractometer was used as the detector.

[0169] The obtained compound (T1) was measured using a differential scanning calorimeter (Hitachi High-Tech Science, SII Exstar 6000 / DSC 6220) under a nitrogen atmosphere and a heating rate of 10 °C / min. The glass transition temperature was determined using the value obtained in the first run.

[0170] The obtained compound (T1) was filled into a 10×50 mm mold and melted at a temperature 100°C higher than the glass transition temperature to produce a 1 mm thick test piece. This test piece was then subjected to a tensile test using a tensile testing apparatus (Orientec, Tensilon) at a tensile speed of 200 mm / min, a clamping distance of 15 mm, and a temperature of 25°C to determine the Young's modulus at 25°C.

[0171] Weigh 0.250 g of the obtained compound (T1) and dilute it with 50 mL of cyclohexane. Next, add 10.0 mL of Wechsler reagent (Wako Pure Chemical Industries, Ltd., 0.1 mol / L iodine chloride-acetic acid solution) and mix thoroughly by shaking. Let the mixture stand for 30 minutes to allow the reaction to proceed. Add 10 mL of 15% potassium iodide aqueous solution and 30 mL of water and stir. Then, slowly add 0.1N sodium thiosulfate aqueous solution (Wako Pure Chemical Industries, Ltd.) dropwise. When the solution turns pale yellow, add 3 drops of starch solution (10 g / L). Then, slowly add 0.1N sodium thiosulfate aqueous solution (Wako Pure Chemical Industries, Ltd.) dropwise until the blue color of the solution disappears (dropping volume Y mL). Next, calculate the blank dropping volume (dropping volume Z mL) similarly, except that no sample (compound (T1)) is added. Determine the iodine value of compound (T1) using the following formula.

[0172] Iodine value (g / 100g) = (ZY) × 1.269 / 0.250

[0173] For the obtained compound (T1), the content of biological carbon was determined according to ASTM D6866-20.

[0174] (Synthetic Examples B-M)

[0175] (Preparation of compound (T1))

[0176] Except for changing monomers (a) and (b) as shown in Table 2, the same procedure as in Synthesis Example A was followed to obtain compound (T1).

[0177] Table 2

[0178]

[0179] (Example 1)

[0180] (1) Manufacturing of adhesive tape

[0181] Relative to 100 parts by weight of the solid component of the acrylic polymer (Synthesis Example 1), 30 parts by weight of compound (T1) (Synthesis Example A) were added. In addition, 30 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) and 2.5 parts by weight of isocyanate-based crosslinking agent (manufactured by Japan Urethane Co., Ltd., trade name "Coronate L45") were added, and the mixture was stirred to obtain a solution of the adhesive composition.

[0182] A 150 μm thick release film is prepared. A solution of the adhesive composition is applied to the release-treated surface of the release film, and it is dried at 100°C for 5 minutes, thereby forming an adhesive layer with a thickness of 50 μm. This adhesive layer is then laminated to the surface of a 50 μm thick corona-treated PET film, which serves as the substrate. Next, the same adhesive layer is laminated to the opposite surface of the substrate using the same method. The film is then cured by heating at 40°C for 48 hours. This results in an adhesive tape with adhesive layers laminated on both sides of the substrate, and the surface of the adhesive layers covered by the release film.

[0183] (2) Determination of gel fraction

[0184] The adhesive tape was cut into 50mm × 100mm flat rectangles to prepare test pieces. The test pieces were immersed in ethyl acetate at 23°C for 24 hours, then removed from the ethyl acetate and dried at 110°C for 1 hour. The weight of the dried test pieces was measured, and the gel fraction was calculated using the following formula (1). It should be noted that no release film for protecting the adhesive layer was laminated on the test pieces.

[0185] Gel fraction (wt%) = 100 × (W2 - W0) / (W1 - W0) (1)

[0186] (W0: Weight of the substrate, W1: Weight of the test piece before impregnation, W2: Weight of the test piece after impregnation and drying)

[0187] (3) Determination of shear storage modulus

[0188] Test samples consisting solely of an adhesive layer were prepared. For the obtained test samples, dynamic viscoelastic spectra from -50°C to 200°C were measured using a viscoelastic spectrometer (IT Measurement & Control Co., Ltd., DVA-200) at a low-rate heating shear deformation mode of 5°C / min and a measurement frequency of 10Hz. The storage modulus at 25°C under these conditions was then determined.

[0189] (4) Determination of the peak temperature of the loss tangent (tanδ)

[0190] A test sample consisting solely of an adhesive layer was prepared. For the obtained test sample, a viscoelastic spectrometer (IT Measurement & Control Co., Ltd., DVA-200) was used to measure the dynamic viscoelastic spectrum from -100℃ to 200℃ under low-rate heating shear deformation mode at 5℃ / min and a measurement frequency of 10Hz. The peak temperature of the loss tangent (tanδ) was obtained from the obtained dynamic viscoelastic spectrum.

[0191] (Examples 2-23, Comparative Examples 1-2)

[0192] As shown in Table 3, the types and amounts of acrylic polymer, compound (T1), tackifying resin (T2), and crosslinking agent were varied, except that the procedure was the same as in Example 1, to obtain the adhesive tape. The tackifying resin (T2) and crosslinking agent used are shown below.

[0193] Rosin ester resin (manufactured by Arakawa Chemical Industry Co., Ltd., trade name "pinecrystal KE359")

[0194] Terpene phenolic resin (manufactured by YASUHARACHEMICAL, trade name "YSPOLYSTAR G150")

[0195] Isocyanate-based crosslinking agent (manufactured by Japan Urethane Co., Ltd., trade name "Coronate L45")

[0196] Epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD-C E5XM")

[0197] (Example 24)

[0198] Relative to 100 parts by weight of the solid component of the styrene-based elastomer (SIS block copolymer, manufactured by ZEON Corporation, Japan, Quintac 3520, styrene content: 15% by weight, diblock ratio: 78% by weight), 30 parts by weight of compound (T1) (synthetic example A) were added. Furthermore, 30 parts by weight of toluene (manufactured by Fuji Chemical Co., Ltd.) were added, and the mixture was stirred to obtain a solution of the adhesive composition.

[0199] A 150 μm thick release film is prepared. A solution of the adhesive composition is applied to the release-treated surface of the release film, and it is dried at 100°C for 5 minutes, thereby forming an adhesive layer with a thickness of 50 μm. This adhesive layer is then laminated to the surface of a 50 μm thick corona-treated PET film, which serves as the substrate. Next, the same adhesive layer is laminated to the opposite surface of the substrate using the same method. The film is then cured by heating at 40°C for 48 hours. This results in an adhesive tape with adhesive layers laminated on both sides of the substrate, and the surface of the adhesive layers covered by the release film.

[0200] (Examples 25-53, Comparative Examples 3-4)

[0201] The types and amounts of the styrene-based elastomer, compound (T1), and tackifying resin (T2) were changed as shown in Tables 4 and 5. Otherwise, the procedure was the same as in Example 24 to obtain the adhesive tape. The styrene-based elastomer and tackifying resin (T2) used are shown below.

[0202] Styrene-based elastomer (SIS block copolymer, manufactured by ZEON Corporation, Japan, Quintac 3520, styrene content: 15% by weight, diblock ratio: 78% by weight)

[0203] Styrene-based elastomer (SIS block copolymer, manufactured by ZEON Corporation, Japan, Quintac 3433N, styrene content: 16% by weight, diblock ratio: 56% by weight)

[0204] Styrene-based elastomer (SIS block copolymer, manufactured by ZEON Corporation, Japan, Quintac 3421, styrene content: 14% by weight, diblock ratio: 26% by weight)

[0205] Styrene-based elastomer (SIS block copolymer, manufactured by ZEON Corporation, Japan, Quintac 3450, styrene content: 19% by weight, diblock ratio: 30% by weight)

[0206] Styrene-based elastomer (SIS block copolymer, manufactured by ZEON Corporation, Japan, Quintac 3280, styrene content: 25% by weight, diblock ratio: 17% by weight)

[0207] Styrene-based elastomer (SBS block copolymer, manufactured by Kraton Polymer Japan, Kraton DX410, styrene content: 18% by weight, diblock ratio: 60% by weight)

[0208] Terpene resin (manufactured by Yasuhara Chemical Co., Ltd., trade name "YS Resin PX1150")

[0209] <Evaluation>

[0210] The adhesive tapes obtained in the examples and comparative examples were evaluated using the following methods. The results are shown in Tables 3-5.

[0211] (1) 180° peel test

[0212] The adhesive tape was cut into 25mm wide pieces to obtain test pieces. The adhesive layer of the obtained test pieces was placed on a stainless steel (SUS304) sheet (manufactured by Nippon Test Panel), a polypropylene (PP) sheet (manufactured by Nippon Test Panel), or a polytetrafluoroethylene (PTFE) sheet (manufactured by Nippon Test Panel). Next, a 2kg rubber roller was driven back and forth once at a speed of 300mm / min on the test piece, thereby bonding the test piece to the stainless steel (SUS304), polypropylene (PP), or polytetrafluoroethylene (PTFE) sheet. Then, the test pieces were left to stand at 23°C for 1 hour to prepare test samples. For the test samples after standing, a tensile test was performed in the 180° direction at a peel speed of 300mm / min according to JIS Z0237 to determine the peel force.

[0213] For SUS's 180° peel test

[0214] ◎: Peel strength is above 20N / inch

[0215] ○: Peel strength is 15 N / inch or higher and less than 20 N / inch

[0216] △: Peel strength is 10 N / inch or higher and less than 15 N / inch

[0217] ×: Peeling force less than 10 N / inch

[0218] For the 180° peel test of PP

[0219] ◎: Peel strength is above 15N / inch

[0220] ○: Peel strength is 10 N / inch or higher and less than 15 N / inch

[0221] △: Peel strength is 5 N / inch or higher and less than 10 N / inch

[0222] ×: Peeling force less than 5N / inch

[0223] For PTFE 180° peel test

[0224] ◎: Peeling force is above 5N / inch

[0225] ○: Peel strength is 3 N / inch or higher and less than 5 N / inch

[0226] △: Peeling force is greater than 1 N / inch and less than 3 N / inch

[0227] ×: Peeling force less than 1 N / inch

[0228] (2) Alkali resistance test

[0229] Adhesive tape 2 was cut into 5mm × 75mm pieces. The release film on one side was peeled off and attached to a 23μm thick polyethylene terephthalate (PET) film as a backing, thus creating a test piece. At 23°C, the release film covering the other adhesive side of the test piece was peeled off, and a 2kg roller was used to press the test piece onto the surface of a stainless steel (SUS304) plate, obtaining the test sample before drug immersion. Sodium hydroxide was diluted with deionized water to prepare an alkaline solution with pH 12. The test sample before drug immersion was immersed in the alkaline solution for 1 day at 60°C. Then, the test sample was removed from the alkaline solution, washed with deionized water, and dried at 23°C for 1 hour, obtaining the test sample after drug immersion. The adhesive tape was observed to peel off from the stainless steel plate from both the pre- and post-drug immersion test samples.

[0230] ○: Peeling without adhesive tape

[0231] △: The ends of the adhesive tape show only slight peeling.

[0232] ×: Full-surface peeling

[0233] Table 3

[0234]

[0235] Table 4

[0236]

[0237] Table 5

[0238]

[0239] Industrial availability

[0240] According to the present invention, a compound capable of improving the adhesive strength of an adhesive composition, particularly for substrates with low polarity, can be provided. Furthermore, according to the present invention, a method for manufacturing the compound, an adhesive composition containing the compound, and an adhesive tape having an adhesive layer containing the adhesive composition can be provided.

Claims

1. An adhesive tape, characterized in that, An adhesive layer comprising an adhesive composition containing a base polymer and a compound having at least one structural unit A selected from structural units (A-1) and (A-1') shown in the following formula, and a structural unit derived from a terpene monomer. In the formula, R 1 These represent hydrogen atoms, aliphatic hydrocarbon groups, aromatic hydrocarbon groups, polar functional groups selected from amino, carboxyl, alkoxy, hydroxyl, nitrile, and nitro groups, aliphatic hydrocarbon groups having polar functional groups selected from amino, carboxyl, carbonyl, alkoxy, hydroxyl, nitrile, and nitro groups, or aromatic hydrocarbon groups having polar functional groups selected from amino, carboxyl, carbonyl, alkoxy, hydroxyl, nitrile, and nitro groups, respectively. n and n' represent 3. The compound is a copolymer obtained by copolymerizing monomer a as shown in the following formula with a terpene monomer. In the formula, R 1 Each of these groups represents a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group selected from amino, carboxyl, alkoxy, hydroxyl, nitrile, and nitro groups, an aliphatic hydrocarbon group having a polar functional group selected from amino, carboxyl, carbonyl, alkoxy, hydroxyl, nitrile, and nitro groups, or an aromatic hydrocarbon group having a polar functional group selected from amino, carboxyl, carbonyl, alkoxy, hydroxyl, nitrile, and nitro groups, with n'' representing 3.

2. The adhesive tape according to claim 1, characterized in that, The compound has a Young's modulus of more than 10 MPa at 25°C.

3. The adhesive tape according to claim 2, characterized in that, The compound has a Young's modulus of less than 10,000 MPa at 25°C.

4. The adhesive tape according to claim 1, characterized in that, The terpene monomers in the compound are α-pinene, β-pinene, or limonene.

5. The adhesive tape according to claim 1, 2, 3 or 4, characterized in that, The content of structural unit A in the compound is more than 1 mol% and less than 60 mol%.

6. The adhesive tape according to claim 1, characterized in that, The content of the structural units derived from terpene monomers in the compound is 40 mol% or more and 99 mol% or less.

7. The adhesive tape according to claim 1, 2, 3, 4 or 6, characterized in that, The weight-average molecular weight of the compound is above 400 and below 10,000.

8. The adhesive tape according to claim 1, 2, 3, 4 or 6, characterized in that, The glass transition temperature of the compound is above 0°C and below 200°C.

9. The adhesive tape according to claim 1, 2, 3, 4 or 6, characterized in that, The iodine value of the compound is greater than 2g / 100g and less than 180g / 100g.

10. The adhesive tape according to claim 1, 2, 3, 4 or 6, characterized in that, Biological carbon accounts for more than 10% of the total carbon content in the compound.

11. The adhesive tape according to claim 1, 2, 3, 4 or 6, characterized in that, The structural unit A is present in the main chain backbone of the compound or at the end of the main chain backbone.

12. The adhesive tape according to claim 1, characterized in that, The content of the compound is more than 1 part by weight and less than 35 parts by weight relative to 100 parts by weight of the base polymer.

13. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, The adhesive composition further contains at least one tackifying resin T2 selected from rosin ester resins, terpene resins and petroleum resins.

14. The adhesive tape according to claim 13, characterized in that, The content of the tackifying resin T2 is 10 parts by weight or more and 100 parts by weight or less relative to 100 parts by weight of the base polymer.

15. The adhesive tape according to claim 14, characterized in that, The content of the tackifying resin T2 is 10 parts by weight or more and 50 parts by weight or less relative to 100 parts by weight of the base polymer.

16. The adhesive tape according to claim 13, characterized in that, The softening temperature of the tackifying resin T2 is above 70°C and below 170°C.

17. The adhesive tape according to claim 13, characterized in that, The hydroxyl value of the tackifying resin T2 is 25 or higher and 150 or lower.

18. The adhesive tape according to claim 1, 2, 3 or 12, characterized in that, The base polymer is an acrylic polymer.

19. The adhesive tape according to claim 18, characterized in that, The acrylic polymer has structural units derived from monomers with crosslinking functional groups.

20. The adhesive tape according to claim 19, characterized in that, In the acrylic polymer, the content of the structural units derived from monomers having crosslinking functional groups is 0.01% by weight or more and 20% by weight or less.

21. The adhesive tape according to claim 18, characterized in that, The weight-average molecular weight of the acrylic polymer is above 200,000 and below 2 million.

22. The adhesive tape according to claim 18, characterized in that, The weight-average molecular weight to number-average molecular weight ratio (Mw / Mn) of the acrylic polymer is greater than 1.05 and less than 5.

0.

23. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, The base polymer is a styrene-based elastomer, which is a block copolymer or its hydrogenation having blocks derived from styrene monomers and blocks derived from conjugated diene monomers.

24. The adhesive tape according to claim 23, characterized in that, The styrene-based elastomer is a styrene-isoprene-styrene block copolymer, i.e., SIS block copolymer, or a styrene-butadiene-styrene block copolymer, i.e., SBS block copolymer.

25. The adhesive tape according to claim 23, characterized in that, The diblock ratio of the styrene-based elastomer is 50% by weight or more.

26. The adhesive tape according to claim 23, characterized in that, The styrene content of the styrene-based elastomer is less than 20% by weight.

27. The adhesive tape according to claim 23, characterized in that, The weight-average molecular weight of the styrene-based elastomer is above 50,000 and below 600,000.

28. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, The gel content of the adhesive layer is more than 10% by weight and less than 70% by weight.

29. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, The shear storage modulus of the adhesive layer at 25°C, measured using a dynamic viscoelasticity measuring device at a frequency of 10 Hz, was 1.0 × 10⁻⁶. 4 Pa or higher and 5.0 × 10 5 Below Pa.

30. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, The adhesive layer was measured using a dynamic viscoelasticity measuring device at a frequency of 10 Hz, and the loss tangent was found to be above -20°C and below 20°C with a peak.

31. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, The thickness of the adhesive layer is greater than 20 μm and less than 100 μm.

32. The adhesive tape according to claim 1, 2, 3, 4, 6 or 12, characterized in that, Used for mounting electronic device components or vehicle components.

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