Hydrocarbon resin and hot melt adhesive composition

Abstract

Provided is a hydrocarbon resin including aliphatic-monomer units or including aliphatic-monomer units and aromatic-monomer units, characterized by having a number-average molecular weight (Mn) in the range of 400-3000, a weight-average molecular weight (Mw) in the range of 700-6000, a Z-average molecular weight (Mz) in the range of 1500-20000, a ratio (Mw / Mn) of the weight-average molecular weight to the number-average molecular weight in the range of 1.0-4.0, a ratio (Mz / Mw) of the Z-average molecular weight to the weight-average molecular weight in the range of 1.0-4.0, and a ratio of the peak-top molecular weight to the weight-average molecular weight (Mw), (peak-top molecular weight) / Mw, in the range of 0.7-1.2 and by having a softening temperature in the range of 80-150°C.

Description

[Technical Field]

[0001] The present invention relates to a hydrocarbon resin capable of providing a hot melt pressure-sensitive adhesive composition having excellent blocking resistance and excellent adhesive performance, a hydrogenated product obtained by hydrogenating the hydrocarbon resin, and a hot melt pressure-sensitive adhesive composition using the hydrocarbon resin or the hydrogenated product. [Background technology]

[0002]

[0003] Hydrocarbon resins obtained by copolymerizing an aliphatic monomer such as a monoolefinically unsaturated hydrocarbon or a chain conjugated diolefin with an aliphatic monomer as required are known, and such hydrocarbon resins are used, for example, as tackifying resins for forming hot-melt pressure-sensitive adhesive compositions.

[0003] As such a hydrocarbon resin, for example, Patent Document 1 discloses a hydrocarbon resin having a glass transition temperature (Tg) of -50°C to 160°C, a number average molecular weight of 3000 or less, a Z average molecular weight of 9000 or less, an oligomer content of 55% by weight or less as measured by gel permeation chromatography (GPC), and an oligomer content of 38% by weight or less as measured by high-resolution thermogravimetric analysis (TGA). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 187243 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, when a hydrocarbon resin is used, for example, as a tackifier resin for forming a hot melt pressure-sensitive adhesive composition, it is required to have excellent blocking resistance and also achieve better adhesive performance from the viewpoint of handling, and the technology disclosed in the above Patent Document 1 does not necessarily provide these properties sufficiently.

[0006] The present invention has been made in view of the above circumstances, and has as its object the provision of a hydrocarbon resin that can provide a hot-melt pressure-sensitive adhesive composition having excellent blocking resistance and excellent adhesive performance. Another object of the present invention is to provide a hydrogenated product obtained by hydrogenating such a hydrocarbon resin, and a hot-melt pressure-sensitive adhesive composition using the same. [Means for solving the problem]

[0007] The present inventors have conducted studies to achieve the above-mentioned object, and have found that the above-mentioned object can be achieved by a hydrocarbon resin in which the number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), ratio of weight average molecular weight to number average molecular weight (Mw / Mn), ratio of Z average molecular weight to weight average molecular weight (Mz / Mw), and softening point are all within specific ranges, and in which the ratio of peak top molecular weight (Mp) to weight average molecular weight (Mw) (Mp / Mw) is controlled in the range of 0.7 to 1.2, thereby completing the present invention.

[0008] That is, according to the present invention, there is provided a hydrocarbon resin comprising aliphatic monomer units, or aliphatic monomer units and aromatic monomer units, The number average molecular weight (Mn) is in the range of 400 to 3000, The weight average molecular weight (Mw) is in the range of 700 to 6000, The Z-average molecular weight (Mz) is in the range of 1500 to 20000, The ratio of weight average molecular weight to number average molecular weight (Mw / Mn) is in the range of 1.0 to 4.0, The ratio of Z-average molecular weight to weight-average molecular weight (Mz / Mw) is in the range of 1.0 to 4.0, The ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) is in the range of 0.7 to 1.2, A hydrocarbon resin is provided which is characterized by having a softening point temperature in the range of 80 to 150°C.

[0009] The hydrocarbon resin of the present invention contains 1 to 70 mass% of 1,3-pentadiene monomer units, 1 to 30 mass% of alicyclic monoolefin monomer units having 4 to 6 carbon atoms, 0 to 50 mass% of acyclic monoolefin monomer units having 4 to 8 carbon atoms, 0 to 10% by mass of alicyclic diolefin monomer units, and It is preferable that the aromatic monoolefin monomer unit is contained in an amount of 0 to 40% by mass. The hydrocarbon resin of the present invention preferably has an aliphatic monomer unit content of 50% by mass or more. The hydrocarbon resin of the present invention preferably has a peak top molecular weight (Mp) in the range of 900 to 5,000.

[0010] The present invention also provides a hydrogenated product obtained by hydrogenating the hydrocarbon resin.

[0011] Furthermore, according to the present invention, there is provided a hot melt pressure-sensitive adhesive composition containing the above hydrocarbon resin and / or the above hydride. The hot melt pressure-sensitive adhesive composition of the present invention preferably further contains a thermoplastic elastomer. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a hydrocarbon resin which can give a hot melt pressure-sensitive adhesive composition having excellent blocking resistance and excellent adhesive performance, a hydrogenated product obtained by hydrogenating such a hydrocarbon resin, and a hot melt pressure-sensitive adhesive composition using the same. DETAILED DESCRIPTION OF THE INVENTION

[0013] The hydrocarbon resin of the present invention is a hydrocarbon resin containing aliphatic monomer units, or aliphatic monomer units and aromatic monomer units, The number average molecular weight (Mn) is in the range of 400 to 3000, The weight average molecular weight (Mw) is in the range of 700 to 6000, The Z-average molecular weight (Mz) is in the range of 1500 to 20000, The ratio of weight average molecular weight to number average molecular weight (Mw / Mn) is in the range of 1.0 to 4.0, The ratio of Z-average molecular weight to weight-average molecular weight (Mz / Mw) is in the range of 1.0 to 4.0, The ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) is in the range of 0.7 to 1.2, The softening point temperature is in the range of 80 to 150°C.

[0014] The hydrocarbon resin of the present invention may contain at least an aliphatic monomer unit, and may contain an aromatic monomer unit in addition to the aliphatic monomer unit.

[0015] (aliphatic monomer unit) First, the aliphatic monomer units contained in the hydrocarbon resin of the present invention will be described. The aliphatic monomer for forming the aliphatic monomer unit may be any monomer that does not contain an aromatic ring and at least contains an unsaturated hydrocarbon. Examples of such aliphatic monomers include 1,3-pentadiene, alicyclic monoolefin monomers having 4 to 6 carbon atoms, acyclic monoolefin monomers having 4 to 8 carbon atoms, and alicyclic diolefin monomers. In the present invention, a mixture containing these aliphatic monomers may be added to the polymerization reaction system used to produce the hydrocarbon resin. In this case, the aliphatic monomers contained in the mixture are used as components of the monomer units that constitute the hydrocarbon resin. It is also possible to use addition-polymerizable components other than the aliphatic monomers contained in the mixture as components of the monomer units of the hydrocarbon resin, with the non-addition-polymerizable components being used as solvents during polymerization. A suitable example of a mixture containing such aliphatic monomers is a C5 fraction containing aliphatic monomers such as 1,3-pentadiene, cyclopentene, and isobutylene.

[0016] The hydrocarbon resin preferably contains, as aliphatic monomer units, 1,3-pentadiene units and alicyclic monoolefin monomer units having 4 to 6 carbon atoms, and may further contain, in addition to these, acyclic monoolefin monomer units and alicyclic diolefin monomer units having 4 to 8 carbon atoms.

[0017] The content of 1,3-pentadiene monomer units in the hydrocarbon resin is not particularly limited, but is preferably 1 to 70 mass%, more preferably 15 to 65 mass%, even more preferably 30 to 60 mass%, and particularly preferably 40 to 60 mass%. By setting the content of 1,3-pentadiene monomer units within the above range, when formed into a hot-melt pressure-sensitive adhesive composition, it is possible to obtain a hot-melt pressure-sensitive adhesive composition having better adhesive performance. The cis / trans isomer ratio in 1,3-pentadiene may be any ratio and is not particularly limited.

[0018] The alicyclic monoolefin having 4 to 6 carbon atoms that forms the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms is a hydrocarbon compound having one ethylenically unsaturated bond and a non-aromatic ring structure in its molecular structure. Specific examples of the alicyclic monoolefin having 4 to 6 carbon atoms include cyclobutene, cyclopentene, cyclohexene, methylcyclobutene, and methylcyclopentene.

[0019] The content of the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms in the hydrocarbon resin is not particularly limited, but is preferably 1 to 30 mass%, more preferably 5 to 28 mass%, even more preferably 15 to 27 mass%, still more preferably 20 to 26 mass%, and particularly preferably 22 to 25 mass%. By setting the content of the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms in the above range, it is possible to obtain a hot-melt pressure-sensitive adhesive composition having even more excellent adhesive performance.

[0020] The proportion of each compound in the alicyclic monoolefin having 4 to 6 carbon atoms may be any proportion and is not particularly limited, but it is preferable that at least cyclopentene is contained, and the proportion of cyclopentene in the alicyclic monoolefin having 4 to 6 carbon atoms is more preferably 50 mass% or more, even more preferably 80 mass% or more, and particularly preferably substantially 100 mass%.

[0021] The acyclic monoolefin having 4 to 8 carbon atoms that forms the acyclic monoolefin monomer unit having 4 to 8 carbon atoms is a chain hydrocarbon compound having 4 to 8 carbon atoms and no ring structure, and having one ethylenically unsaturated bond in its molecular structure. Specific examples of the acyclic monoolefin having 4 to 8 carbon atoms include butenes such as 1-butene, 2-butene, and isobutylene (2-methylpropene); pentenes such as 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, and 2-methyl-2-butene; hexenes such as 1-hexene, 2-hexene, and 2-methyl-1-pentene; heptenes such as 1-heptene, 2-heptene, and 2-methyl-1-hexene; and octenes such as 1-octene, 2-octene, 2-methyl-1-heptene, and diisobutylene (2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-1-pentene).

[0022] The content of the acyclic monoolefin monomer unit having 4 to 8 carbon atoms in the hydrocarbon resin is not particularly limited, but is preferably 0 to 50 mass%, more preferably 1 to 50 mass%, even more preferably 10 to 45 mass%, especially preferably 14 to 40 mass%, particularly preferably 15 to 37 mass%, and most preferably 16 to 35 mass%. By setting the content of the acyclic monoolefin monomer unit having 4 to 8 carbon atoms in the above range, it is possible to obtain a hot-melt pressure-sensitive adhesive composition having better adhesive performance.

[0023] The proportion of each corresponding compound (including isomers) in the acyclic monoolefin having 4 to 8 carbon atoms may be any proportion and is not particularly limited, but it is preferable that at least one selected from the group consisting of 2-methyl-2-butene, isobutylene, and diisobutylene is included, and it is more preferable that the total amount of 2-methyl-2-butene, isobutylene, and diisobutylene accounts for 50 mass% or more of the acyclic monoolefin having 4 to 8 carbon atoms.

[0024] The alicyclic diolefin forming the alicyclic diolefin monomer unit is a hydrocarbon compound having two or more ethylenically unsaturated bonds and a non-aromatic ring structure in its molecular structure. Specific examples of the alicyclic diolefin include cyclopentadiene, cyclopentadiene polymers such as dicyclopentadiene, methylcyclopentadiene, and methylcyclopentadiene polymers.

[0025] The content of the alicyclic diolefin monomer unit in the hydrocarbon resin is not particularly limited, but is preferably 0 to 10 mass%, more preferably 0.03 to 5 mass%, even more preferably 0.05 to 4 mass%, and particularly preferably 0.08 to 3 mass%. By setting the content of the alicyclic diolefin monomer unit within the above range, when the hot melt pressure-sensitive adhesive composition is prepared, the adhesive performance can be made even more excellent.

[0026] The hydrocarbon resin of the present invention may also contain other monomer units in addition to 1,3-pentadiene monomer units, alicyclic monoolefin monomer units having 4 to 6 carbon atoms, aromatic monoolefin monomer units, acyclic monoolefin monomer units having 4 to 8 carbon atoms, and alicyclic diolefin monomer units.

[0027] The other monomers forming such other monomer units are not particularly limited as long as they are addition-polymerizable compounds that can be addition-copolymerized with 1,3-pentadiene, etc. Examples of such other monomers include unsaturated hydrocarbons having 4 to 6 carbon atoms other than 1,3-pentadiene, such as 1,3-butadiene, 1,2-butadiene, isoprene, 1,3-hexadiene, and 1,4-pentadiene; alicyclic monoolefins having 7 or more carbon atoms, such as cycloheptene; and acyclic monoolefins having 4 to 8 carbon atoms other than 1,3-pentadiene, such as ethylene, propylene, and nonene.

[0028] The content of other monomer units in the hydrocarbon resin is usually in the range of 0 to 30% by mass, preferably 0 to 25% by mass, and more preferably 0 to 20% by mass.

[0029] The content of aliphatic monomer units in the hydrocarbon resin is not particularly limited, but 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 80% by mass or more.

[0030] (aromatic monomer unit) The hydrocarbon resin of the present invention may contain aromatic monomer units in addition to aliphatic monomer units. Using a hydrocarbon resin containing aromatic monomer units in addition to aliphatic monomer units can further enhance the holding power of a hot-melt pressure-sensitive adhesive composition. The aromatic monomer for forming the aromatic monomer units may be any monomer having an aromatic ring and capable of copolymerizing with an aliphatic monomer, such as an aromatic monoolefin monomer. In addition, in the present invention, a mixture containing an aromatic monomer such as an aromatic monoolefin monomer may be added to the polymerization reaction system when producing the hydrocarbon resin. In this case, the aromatic monomer contained in the mixture is used as a component of the monomer units constituting the hydrocarbon resin. It is also possible to use addition-polymerizable components other than the aromatic monomer contained in the mixture as components of the monomer units of the hydrocarbon resin, with the non-addition-polymerizable component being used as a solvent during polymerization. As a mixture containing such an aromatic monomer, for example, a C9 fraction containing aromatic monomers such as styrene compounds and indene compounds can be suitably used.

[0031] Aromatic monoolefin monomers are aromatic compounds with one ethylenically unsaturated bond in their molecular structure. Examples of aromatic monoolefins include styrene compounds such as styrene, α-methylstyrene, β-methylstyrene, and vinyltoluene; indene compounds such as indene and 1-methylindene; and coumarone.

[0032] The content of the aromatic monoolefin monomer unit in the hydrocarbon resin is not particularly limited, but is preferably 0 to 40 mass%, more preferably 3 to 35 mass%, even more preferably 8 to 25 mass%, and particularly preferably 11 to 19 mass%. By setting the content of the aromatic monoolefin monomer unit within the above range, when it is made into a hot melt pressure-sensitive adhesive composition, it is possible to make it possible to make the holding power more excellent.

[0033] The hydrocarbon resin of the present invention has a number-average molecular weight (Mn) in the range of 400 to 3000, preferably 450 to 2500, more preferably 500 to 2000, and even more preferably 700 to 1500. The hydrocarbon resin of the present invention has a weight-average molecular weight (Mw) in the range of 700 to 6000, preferably 900 to 5000, more preferably 1000 to 4000, and even more preferably 1500 to 3200. The hydrocarbon resin of the present invention has a Z-average molecular weight (Mz) in the range of 1500 to 20000, preferably 1800 to 15000, more preferably 2000 to 10000, and even more preferably 2500 to 8000.

[0034] The ratio of the weight-average molecular weight to the number-average molecular weight (Mw / Mn) of the hydrocarbon resin of the present invention is in the range of 1.0 to 4.0, preferably in the range of 1.1 to 3.5, more preferably in the range of 1.2 to 3.0, even more preferably in the range of 1.4 to 2.8, and particularly preferably in the range of 1.5 to 2.6. The ratio of the Z-average molecular weight to the weight-average molecular weight of the hydrocarbon resin of the present invention (Mz / Mw) is in the range of 1.0 to 4.0, preferably in the range of 1.1 to 3.5, more preferably in the range of 1.2 to 3.0, and even more preferably in the range of 1.4 to 2.8.

[0035] By setting the number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) and ratio of the Z average molecular weight to the weight average molecular weight (Mz / Mw) of the hydrocarbon resin within the above ranges, when the hydrocarbon resin is made into a hot melt pressure-sensitive adhesive composition, the compatibility with the base polymer can be improved, and thus the adhesive performance can be improved.

[0036] The number-average molecular weight (Mn), weight-average molecular weight (Mw), Z-average molecular weight (Mz), ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn), and ratio of Z-average molecular weight to weight-average molecular weight (Mz / Mw) of hydrocarbon resins can be determined as polystyrene-equivalent values ​​by gel permeation chromatography using tetrahydrofuran as a developing solvent.

[0037] In addition, in the present invention, the number-average molecular weight (Mn), weight-average molecular weight (Mw), Z-average molecular weight (Mz), ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn), and ratio of Z-average molecular weight to weight-average molecular weight (Mz / Mw) of the hydrocarbon resin are set within the above-mentioned ranges, and the ratio of peak-top molecular weight (Mp) to weight-average molecular weight (Mw) of the hydrocarbon resin (Mp / Mw) is set within the range of 0.7 to 1.2. In the present invention, by setting the ratio of peak-top molecular weight (Mp) to weight-average molecular weight (Mw) of the hydrocarbon resin (Mp / Mw) within the range of 0.7 to 1.2, the hydrocarbon resin has excellent blocking resistance and, when used in a hot-melt pressure-sensitive adhesive composition, has excellent adhesive performance (more specifically, a well-balanced and excellent peel adhesion strength and loop tack strength). If the ratio of peak-top molecular weight (Mp) to weight-average molecular weight (Mw) (Mp / Mw) is too low, blocking resistance decreases. On the other hand, if the ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) is too high, handling and production stability will be poor. The ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) may be in the range of 0.7 to 1.2, preferably 0.7 to 1.1, more preferably 0.7 to 1.02, even more preferably 0.7 to 0.98, particularly preferably 0.71 to 0.94, and most preferably 0.74 to 0.88. The peak top molecular weight (Mp) of the hydrocarbon resin is not particularly limited, but is preferably in the range of 900 to 5000, more preferably 1000 to 4000, even more preferably 1100 to 3400, and particularly preferably 1200 to 2800.

[0038] The ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) is determined by measuring the weight average molecular weight (Mw) and peak top molecular weight (Mp) of a hydrocarbon resin as polystyrene equivalent values ​​using gel permeation chromatography (GPC) with tetrahydrofuran as the developing solvent, and then calculating the ratio (Mp / Mw). The peak top molecular weight (Mp) is the molecular weight at which the maximum detected value (elution volume) is observed in the GPC chart obtained by gel permeation chromatography. Mp / Mw represents the relationship between the peak top molecular weight (Mp), which is the molecular weight at which the maximum detected value (elution volume) is observed, and the weight average molecular weight (Mw). A smaller Mp / Mw value indicates a relatively high content of low molecular weight components, while a larger Mp / Mw value indicates a relatively high content of high molecular weight components. When two or more peaks are present in a GPC chart, the molecular weight corresponding to the largest peak is taken as the peak top molecular weight (Mp).

[0039] In the present invention, the number-average molecular weight (Mn), weight-average molecular weight (Mw), Z-average molecular weight (Mz), ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn), ratio of Z-average molecular weight to weight-average molecular weight (Mz / Mw), and ratio of peak-top molecular weight (Mp) to weight-average molecular weight (Mw) of the hydrocarbon resin (Mp / Mw) can be adjusted by the type and amount of monomer used in polymerization and the polymerization conditions. In particular, the ratio of peak-top molecular weight (Mp) to weight-average molecular weight (Mw) of the hydrocarbon resin (Mp / Mw) can be controlled by an appropriate combination of the type and amount of monomer used in polymerization, the amount of polymerization catalyst used, the polymerization temperature, and the mixing temperature and mixing time when the polymerization catalyst is mixed in advance with a volatile solvent. For example, the ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) of the hydrocarbon resin tends to be larger as the amount of polymerization catalyst used is smaller and the polymerization temperature is lower. Also, the ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) of the hydrocarbon resin tends to be larger as the mixing time when the polymerization catalyst is mixed in the volatile solvent in advance is longer.

[0040] The softening point of the hydrocarbon resin of the present invention is in the range of 80 to 150°C, preferably in the range of 85 to 145°C, more preferably in the range of 90 to 140°C, and even more preferably in the range of 90 to 100°C. By setting the softening point within the above range, blocking can be effectively suppressed, and further, when used in a hot-melt pressure-sensitive adhesive composition, the resin can be easily melted during hot-melt kneading and compatibility with the base polymer can be improved, thereby improving adhesive performance. The softening point of the hydrocarbon resin can be measured in accordance with JIS K6863.

[0041] <Method of manufacturing hydrocarbon resin> The method for producing the hydrocarbon resin of the present invention is not particularly limited, but examples thereof include a method of subjecting a monomer mixture for constituting the hydrocarbon resin to addition polymerization, and a preferred example thereof is a method of addition polymerization using a Friedel-Crafts type cationic polymerization catalyst.

[0042] The Friedel-Crafts cationic polymerization catalyst is not particularly limited, and examples thereof include halides of aluminum, iron, tantalum, zirconium, tin, beryllium, boron, antimony, gallium, bismuth, molybdenum, etc. Among these, aluminum halides such as aluminum chloride (AlCl3) and aluminum bromide (AlBr3) are preferred. The amount of the Friedel-Crafts cationic polymerization catalyst used is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, even more preferably 0.4 to 2.0 parts by mass, and particularly preferably 0.5 to 1.7 parts by mass, per 100 parts by mass of the monomer mixture used in polymerization.

[0043] During polymerization, a halogenated hydrocarbon may be used in addition to the Friedel-Crafts type cationic polymerization catalyst, since this allows for further enhancement of catalytic activity.

[0044] Specific examples of halogenated hydrocarbons include halogenated hydrocarbons in which a halogen atom is bonded to a tertiary carbon atom, such as t-butyl chloride, t-butyl bromide, 2-chloro-2-methylbutane, and triphenylmethyl chloride; and halogenated hydrocarbons in which a halogen atom is bonded to a carbon atom adjacent to a carbon-carbon unsaturated bond, such as benzyl chloride, benzyl bromide, (1-chloroethyl)benzene, allyl chloride, 3-chloro-1-propyne, 3-chloro-1-butene, 3-chloro-1-butyne, and cinnamyl chloride. Among these, t-butyl chloride and benzyl chloride are preferred from the viewpoint of achieving an excellent balance between catalytic activity and ease of handling. The halogenated hydrocarbons may be used alone or in combination of two or more. The amount of halogenated hydrocarbon used, expressed as a molar ratio relative to the Friedel-Crafts cationic polymerization catalyst, is preferably in the range of 0.05 to 50, more preferably 0.1 to 10.

[0045] Furthermore, from the viewpoint of better controlling the polymerization reaction, it is preferable to carry out the polymerization reaction by adding a volatile solvent to the polymerization reaction system. The type of volatile solvent is not particularly limited as long as it does not inhibit the polymerization reaction, but saturated aliphatic hydrocarbons or aromatic hydrocarbons are preferred. Examples of saturated aliphatic hydrocarbons include linear saturated aliphatic hydrocarbons having 5 to 10 carbon atoms, such as n-pentane, n-hexane, 2-methylpentane, 3-methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,2,3-trimethylbutane, and 2,2,4-trimethylpentane; and cyclic saturated aliphatic hydrocarbons having 5 to 10 carbon atoms, such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane. Examples of aromatic hydrocarbons include aromatic hydrocarbons having 6 to 10 carbon atoms, such as benzene, toluene, and xylene. The volatile solvent may be used alone or in combination of two or more. The amount of the volatile solvent used is not particularly limited, but is preferably 10 to 1,000 parts by mass, more preferably 50 to 500 parts by mass, per 100 parts by mass of the monomer mixture used in the polymerization.

[0046] In carrying out the polymerization reaction, the order in which the monomer mixture and the polymerization catalyst components are added to a polymerization reactor is not particularly limited, and they may be added in any order. However, from the viewpoint of favorably controlling the polymerization reaction and controlling the ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw), a preferred method is to add the polymerization catalyst to a volatile solvent in advance and mix them to make the polymerization catalyst dispersed in the volatile solvent, and then add the monomer mixture to the polymerization reactor to start the polymerization reaction.

[0047] When the polymerization catalyst is added to the volatile solvent in advance and mixed, it is preferable to set conditions such that the polymerization catalyst is uniformly dispersed in the volatile solvent, the mixing temperature is preferably 40 to 75°C, more preferably 50 to 70°C, and even more preferably 55 to 65°C, and the mixing time is preferably 5 to 30 minutes, more preferably 6 to 20 minutes.

[0048] The polymerization temperature when carrying out the polymerization reaction is not particularly limited, but is preferably 30 to 80° C., more preferably 45 to 75° C., and even more preferably 50 to 68° C. The polymerization reaction time may be appropriately selected, but is usually 10 minutes to 12 hours, and preferably 30 minutes to 6 hours.

[0049] The polymerization reaction can be terminated by adding a polymerization terminator such as methanol, an aqueous sodium hydroxide solution, or an aqueous ammonia solution to the polymerization reaction system when a desired polymerization conversion rate is achieved, thereby obtaining a polymer solution containing the hydrocarbon resin.

[0050] After the polymerization, a polymerization terminator may be added to inactivate the polymerization catalyst, and the resulting catalyst residue insoluble in the solvent may be removed by filtration or the like.

[0051] After the polymerization, it is preferable to remove volatile organic compound components such as the solvent, unreacted monomers, and low-molecular-weight oligomer components from the polymer solution containing the hydrocarbon resin by steam distillation or the like.

[0052] If necessary, the obtained hydrocarbon resin may be subjected to a hydrogenation reaction to hydrogenate the carbon-carbon double bonds in the hydrocarbon resin, thereby converting it into a hydrogenated product. The hydrogenation of the hydrocarbon resin can be carried out by contacting the hydrocarbon resin with hydrogen in the presence of a hydrogenation catalyst.

[0053] The hydrogenation catalyst is not particularly limited, but a nickel catalyst is preferred. In particular, from the viewpoint of high reactivity, a catalyst containing, as a main component, a compound in which nickel as a metal is supported on a supported inorganic compound as a support is preferred. Specific examples of the supported inorganic compound as a support include silica, alumina, boria, silica-alumina, diatomaceous earth, clay, magnesia, magnesia-silica (silica-magnesium oxide), titania, and zirconia. Among these, magnesia-silica is preferred from the viewpoint of reactivity.

[0054] <Hot melt adhesive composition> The hot melt pressure-sensitive adhesive composition of the present invention contains the hydrocarbon resin of the present invention described above. Alternatively, the hot melt pressure-sensitive adhesive composition may contain, together with or in addition to the hydrocarbon resin of the present invention, a hydrogenated product obtained by hydrogenating the hydrocarbon resin of the present invention described above.

[0055] The hot melt pressure-sensitive adhesive composition of the present invention can usually be obtained by blending the hydrocarbon resin and / or its hydrogenated product of the present invention with a thermoplastic elastomer.

[0056] The thermoplastic elastomer is not particularly limited, and any thermoplastic elastomer used as a base polymer for hot-melt pressure-sensitive adhesives can be used without limitation. However, in terms of further enhancing the effects of the present invention, at least one selected from ethylene-vinyl acetate copolymer, styrene-based thermoplastic elastomer, and polyolefin-based thermoplastic elastomer is preferred.

[0057] The ethylene-vinyl acetate copolymer is not particularly limited, but preferably has a vinyl acetate monomer unit content of 10 to 50 mass%, more preferably 15 to 40 mass%, and even more preferably 15 to 35 mass%. Furthermore, the ethylene-vinyl acetate copolymer preferably has a melt flow rate of 1 to 500 g / 10 min.

[0058] The ethylene-vinyl acetate copolymer is commercially available, and examples thereof that can be suitably used include "EVAFLEX EV220 (product name)" manufactured by DuPont-Mitsui Polychemicals Co., Ltd. and "VA900 (product name)" manufactured by Lotte Chemical Co., Ltd.

[0059] The styrene-based thermoplastic elastomer is not particularly limited, and examples thereof include random, block, and graft copolymers of a styrene-based monomer with another monomer copolymerizable with the styrene-based monomer, hydrogenated products of such copolymers, and block copolymers containing at least one aromatic vinyl polymer block and at least one conjugated diene polymer block. Specific examples of such block copolymers that can be suitably used include styrene-isoprene diblock copolymers, styrene-isoprene-styrene triblock copolymers, isoprene-styrene-isoprene triblock copolymers, styrene-isoprene-styrene-isoprene tetrablock copolymers, and mixtures thereof.

[0060] Furthermore, the polyolefin-based thermoplastic elastomer is not particularly limited, but examples thereof include ethylene / α-olefin copolymers. The α-olefin copolymerized with ethylene to obtain the ethylene / α-olefin copolymer is not particularly limited, but examples thereof include α-olefins having 3 to 20 carbon atoms such as propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene, and are preferred, with α-olefins having 6 to 8 carbon atoms being more preferred, and 1-octene being even more preferred. The α-olefins may be used alone or in combination of two or more.

[0061] The content of α-olefin units in the ethylene / α-olefin copolymer is not particularly limited, but the proportion of α-olefin units relative to all monomer units is preferably 20 to 40 mol %. Furthermore, the ethylene / α-olefin copolymer that can be used preferably has a melt flow rate of 200 to 1500 g / 10 min.

[0062] The blending ratio of the thermoplastic elastomer to the hydrocarbon resin and / or its hydride in the hot melt adhesive composition of the present invention is not particularly limited, but the total amount of the hydrocarbon resin and its hydride per 100 parts by mass of the thermoplastic elastomer is preferably 50 to 500 parts by mass, more preferably 80 to 400 parts by mass. When the blending ratio of the hydrocarbon resin and / or its hydride is within this range, the adhesive performance of the hot melt adhesive composition becomes particularly good.

[0063] The hot-melt adhesive composition of the present invention may consist solely of the hydrocarbon resin and / or its hydrogenated product and a thermoplastic elastomer of the present invention, or may further contain other components. Other components that may be contained in the hot-melt adhesive composition include waxes, softeners, antioxidants, tackifier resins other than the hydrocarbon resin and its hydrogenated product of the present invention, polymers other than those mentioned above, heat stabilizers, UV absorbers, fillers, and other compounding agents. The hot-melt adhesive composition is preferably a solvent-free composition.

[0064] In obtaining the hot-melt pressure-sensitive adhesive composition of the present invention, the method for mixing the above-mentioned hydrocarbon resin and / or its hydride, thermoplastic elastomer, and other components added as necessary is not particularly limited, and examples thereof include a method in which each component is dissolved in a solvent and mixed uniformly, and then the solvent is removed by heating, or a method in which each component is melt-mixed using a kneader, etc. From the viewpoint of more efficient mixing, melt-mixing is preferred among these methods. The temperature during melt-mixing is not particularly limited, but is usually in the range of 100 to 200°C.

[0065] The hot-melt adhesive composition of the present invention contains the hydrocarbon resin and / or its hydride as a tackifying resin, and therefore has excellent adhesive performance, particularly a well-balanced adhesive force and loop tack strength. Therefore, by utilizing these properties, the hot-melt adhesive composition of the present invention can be applied to the adhesion of various members, and can achieve energy-saving, highly productive, and high-holding adhesion. The hot-melt adhesive composition of the present invention is preferably used, for example, as an adhesive for various adhesive tapes and labels. Specifically, by forming an adhesive layer comprising the hot-melt adhesive composition of the present invention on a sheet-like substrate constituting the adhesive tape or label, the hot-melt adhesive composition can be preferably used as an adhesive tape or label comprising the substrate and an adhesive layer comprising the hot-melt adhesive composition of the present invention. [Example]

[0066] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Note that "parts" and "%" are by mass unless otherwise specified. The test methods used in the present examples and comparative examples are as follows.

[0067] [Number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), peak top molecular weight (Mp), molecular weight distribution (Mw / Mn, Mz / Mw), ratio of weight average molecular weight (Mw) to peak top molecular weight (Mp) (Mp / Mw) of hydrocarbon resin] The hydrocarbon resins were analyzed by gel permeation chromatography (GPC) to determine the number-average molecular weight (Mn), weight-average molecular weight (Mw), Z-average molecular weight (Mz), and peak-top molecular weight (Mp) in terms of standard polystyrene. Based on these results, the molecular weight distributions Mw / Mn, Mz / Mw, and the ratio of weight-average molecular weight (Mw) to peak-top molecular weight (Mp) (Mp / Mw) were calculated. Gel permeation chromatography was performed using a Tosoh HLC-8320GPC instrument and three Tosoh TSKgel SuperMultipore HZ columns connected together. Tetrahydrofuran was used as the solvent at 40°C and a flow rate of 1.0 mL / min.

[0068] [Blocking property of hydrocarbon resin] The hydrocarbon resin was crushed into pieces of approximately 5 mm square to prepare a number of small sample pieces of 30 g each. These were placed in a 10 cm x 10 cm polyethylene bag, a 2 kg weight was placed on top, and the bag was kept at 40°C for 12 hours. After the bag was kept, the blocking properties of the small sample pieces were evaluated according to the following criteria. ◯: No blocking occurred at all. △: Slight blocking was observed.

[0069] [Softening point of hydrocarbon resin] The hydrocarbon resin was measured according to JIS K6863.

[0070] [Peel Adhesion Strength of Hot Melt Pressure-Sensitive Adhesive Composition] The obtained hot-melt pressure-sensitive adhesive composition was melt-coated onto a 25 μm PET film to a thickness of 20 to 30 μm to obtain a coated sheet. This coated sheet was then cut to obtain test pieces. Using the test pieces obtained in this way, the peel adhesion strength (N / 10 mm) at room temperature was evaluated in accordance with PSTC-101 (180° peel adhesion test by the US Adhesive Tape Committee) using a stainless steel plate as the adherend, by measuring at a pulling rate of 300 mm / min and a temperature of 23°C. The higher the value, the better the peel adhesion strength.

[0071] [Loop tack (23°C) of hot melt adhesive composition] Using test pieces obtained in the same manner as above, loop tack (N / 25 mm) at room temperature (23°C) was evaluated in accordance with PSTC-16 (loop tack test by the US Adhesive Tape Committee) using stainless steel plates as adherends, at a test speed of 300 mm / min, with an adhesive joint of 25 x 25 mm, and at a temperature of 23°C. The higher the value, the better the loop tack strength (initial adhesive strength).

[0072] [Holding power of hot melt adhesive composition] Using test pieces obtained in the same manner as above, holding power was evaluated in accordance with PSTC-107 Procedure A (a holding power test method established by the US Adhesive Tape Committee) using stainless steel plates as adherends, with a bonded area of ​​10 x 25 mm, a load of 1000 ± 5 g, and a temperature of 50°C, by measuring the time (minutes) until peeling. The higher the value, the better the holding power.

[0073] Example 1 (Production of hydrocarbon resins) A polymerization reactor was charged with 52.7 parts of cyclopentane as a hydrocarbon solvent and heated to 60°C. Then, 1.0 parts of aluminum chloride as a polymerization catalyst was added. While maintaining the temperature at 60°C, the mixture was mixed for 10 minutes to uniformly disperse the aluminum chloride in the cyclopentane. After the 10-minute mixing period, a mixture consisting of 43.6 parts of 1,3-pentadiene, 24.3 parts of cyclopentene, 30.3 parts of isobutylene, 1.4 parts of diisobutylene, 0.1 parts of dicyclopentadiene, 0.3 parts of C4-C6 unsaturated hydrocarbons, 15.8 parts of C4-C6 saturated hydrocarbons, and 0.1 parts of toluene was added continuously to the polymerization reactor over a 60-minute period, while maintaining the temperature at 60°C. The polymerization reaction was then terminated by adding aqueous sodium hydroxide to the polymerization reactor. The types and amounts of the components in the polymerization reactor during the polymerization reaction are summarized in Table 1. The precipitate formed upon termination of the polymerization was removed by filtration to obtain a polymer solution containing a hydrocarbon resin and unreacted monomers. The polymer solution was then placed in a distillation kettle and heated under a nitrogen atmosphere to remove the polymerization solvent and unreacted monomers, yielding a hydrocarbon resin. Because the amount of unreacted monomer was extremely small, the monomer composition of the resulting hydrocarbon resin was determined to be substantially the same as the monomer composition used in the polymerization (the same applies to Examples 2 to 7 and Comparative Examples 1 to 3, described below). The resulting hydrocarbon resin was then tested and evaluated for number-average molecular weight (Mn), weight-average molecular weight (Mw), Z-average molecular weight (Mz), peak-top molecular weight (Mp), molecular weight distribution (Mw / Mn, Mz / Mw), ratio of weight-average molecular weight (Mw) to peak-top molecular weight (Mp) (Mp / Mw), softening point, and blocking property according to the methods described above. The results are shown in Table 1.

[0074] (Preparation of Hot Melt Adhesive Composition) 100 parts of a styrene-isoprene-styrene block copolymer (trade name "Quintac® 3421", manufactured by Nippon Zeon Co., Ltd.) was placed in a mixing blade kneader, to which 100 parts of the hydrocarbon resin obtained above, 10 parts of a softener (trade name "Sunpure N100", naphthenic process oil, manufactured by Nippon Sun Oil Co., Ltd.), and 1.5 parts of an antioxidant (trade name "Irganox 1010", manufactured by BASF) were added. The system was then purged with nitrogen gas, and the mixture was kneaded at 160 to 180°C for 1 hour to prepare a hot-melt pressure-sensitive adhesive composition. The peel adhesion, loop tack, and holding power of the obtained hot-melt pressure-sensitive adhesive composition were then measured. The results are shown in Table 2.

[0075] Examples 2 to 7 The hydrocarbon resins of Examples 2 to 7 were obtained in the same manner as in Example 1, except that the types and amounts of components added to the polymerization reactor, the mixing temperature and mixing time when mixing aluminum chloride as a polymerization catalyst, and the polymerization temperature were changed as shown in Table 1 below. The C9 fraction and styrene not described in Example 1 were mixed with 1,3-pentadiene and the like and subjected to polymerization. The C9 fraction mainly contained styrene, α-methylstyrene, β-methylstyrene, vinyltoluene, and indene as aromatic monomers, and the amounts used in Table 1 are shown in terms of aromatic monomers. The obtained hydrocarbon resins were then subjected to various tests and evaluations in the same manner as in Example 1. The results are shown in Table 1.

[0076] In addition, hot melt pressure-sensitive adhesive compositions were prepared in the same manner as in Example 1, except that the hydrocarbon resins of Examples 2 to 7 obtained above were used, and the various tests and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0077] Comparative Examples 1 to 3 The hydrocarbon resins of Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the types and amounts of components added to the polymerization reactor, the mixing temperature and mixing time when mixing aluminum chloride as a polymerization catalyst, and the polymerization temperature were changed as shown in Table 1 below. The C9 fraction and styrene not described in Example 1 were mixed with 1,3-pentadiene and the like and subjected to polymerization. The C9 fraction mainly contained styrene, α-methylstyrene, β-methylstyrene, vinyltoluene, and indene as aromatic monomers, and the amounts used in Table 1 are shown in terms of aromatic monomers. The obtained hydrocarbon resins were then subjected to various tests and evaluations in the same manner as in Example 1. The results are shown in Table 1.

[0078] In addition, hot melt pressure-sensitive adhesive compositions were prepared in the same manner as in Example 1, except that the hydrocarbon resins of Comparative Examples 1 to 3 obtained above were used, and the various tests and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0079] [Table 1]

[0080] [Table 2]

[0081] From the results of Examples 1 to 7 and Comparative Examples 1 to 3 shown in Tables 1 and 2, hydrocarbon resins whose number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), ratio of weight average molecular weight to number average molecular weight (Mw / Mn), ratio of Z average molecular weight to weight average molecular weight (Mz / Mw) and softening point are within the ranges specified in the present invention and whose ratio of peak top molecular weight (Mp) to weight average molecular weight (Mw) (Mp / Mw) is in the range of 0.7 to 1.2 are excellent in blocking resistance, and hot melt pressure-sensitive adhesive compositions obtained using these are excellent in peel adhesion strength and loop tack strength.

Claims

1. A hydrocarbon resin comprising aliphatic monomer units or aliphatic and aromatic monomer units, The number average molecular weight (Mn) is in the range of 400 to 3000, The weight average molecular weight (Mw) is in the range of 700 to 6000, The Z-average molecular weight (Mz) is in the range of 1,500 to 20,000; The ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) is in the range of 1.0 to 4.0, the ratio of Z-average molecular weight to weight-average molecular weight (Mz / Mw) is in the range of 1.0 to 4.0; the ratio (Mp / Mw) of the peak top molecular weight (Mp) to the weight average molecular weight (Mw) is in the range of 0.7 to 1.2; The softening point temperature is in the range of 80 to 150°C, The content of 1,3-pentadiene monomer units is 30 to 70 mass %, the content of alicyclic monoolefin monomer units having 4 to 6 carbon atoms is 15 to 30 mass %, A hydrocarbon resin having a content of acyclic monoolefin monomer units having 4 to 8 carbon atoms of 10 to 50 mass %.

2. The content of alicyclic diolefin monomer units is 0 to 10 mass %, 2. The hydrocarbon resin according to claim 1, wherein the content of aromatic monoolefin monomer units is 0 to 40% by mass.

3. 3. The hydrocarbon resin according to claim 1, wherein the content of aliphatic monomer units is 60% by mass or more.

4. 4. The hydrocarbon resin according to any one of 1 to 3, having a peak top molecular weight (Mp) in the range of 900 to 5,000.

5. A hydrogenated product obtained by hydrogenating the hydrocarbon resin according to any one of claims 1 to 4.

6. A hot-melt pressure-sensitive adhesive composition comprising the hydrocarbon resin according to any one of claims 1 to 4 and / or the hydride according to claim 5.

7. The hot melt pressure-sensitive adhesive composition according to claim 6, further comprising a thermoplastic elastomer.

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