JP5507182B2 - Hot melt sealant - Google Patents

Description

  The present invention relates to a hot melt sealant comprising a thermoplastic elastomer composition having improved flexibility, processability, heat resistance, vibration damping properties, and oxygen gas barrier properties.

  Sealants are used in a wide range of industrial fields such as architecture, electricity, and automobiles. There are two types of sealants: cross-linked and hot-melt types. Cross-linked types include silicone sealants, urethane-based sealants, polysulfide-based sealants, and vulcanized rubber sealants, while hot-melt types include EVA-based sealants and soft vinyl chloride-based sealants. There are thermoplastic elastomer sealants such as sealants, butyl rubber sealants, and styrene thermoplastic elastomers. Sealants are widely used in automobiles and building materials as a material that fills joints to obtain water tightness and air tightness. The sealant is required to have high hermeticity, and in many cases, it is required to have characteristics such as flexibility and high mechanical strength, although it varies depending on the application to be used.

  Currently, such parts are required to be sealed in cartridges filled with reactive solidifying sealants such as silicone sealants, urethane sealants, and polysulfide sealants at the factory or work site. The reactive solidified sealant is filled or bonded during assembly or after assembly, or is attached during assembly using a natural rubber or synthetic rubber molded packing, or a butyl rubber sealant or styrene heat After a hot melt sealant such as a plastic elastomer sealant is applied at the time of assembling the seal portion, it is assembled.

  In order to obtain the desired performance, the reaction-cured sealant that is constructed using a cartridge or the like must be left standing for a long time in order to react and solidify after filling or bonding to the seal part. In addition, it was not easy to peel off after installation, and there was a problem in dismantling when trouble occurred or after use. In addition, due to its characteristics, the reaction-solidifying sealant cannot be applied in advance to the seal site, and there is a problem that it can only be applied at the time of assembly or after assembly.

  The use of natural rubber or synthetic rubber-based molded packing as a sealing material has no problem in dismantling properties, but a mold according to each packing shape is required, and in use at high temperatures, The molded packing has a large compression set and has a problem that it is difficult to maintain hermeticity for a long time. In addition, automation is difficult in the construction, and there is a problem in productivity because construction and assembly that rely on human hands are necessary.

  On the other hand, butyl rubber sealant is a hot melt sealant, and it is excellent in productivity, gas barrier property, and vibration control property that can be processed and assembled in a short time after being applied directly to the part where sealing is required and cooled. From the point of view, it is used as an adhesive sealing material for various airtight members. However, depending on the use environment, the compression set performance is inferior particularly under high temperature conditions (compression set at 70 ° C. and 100 ° C. is 90% or more). If the seal part peels off or breaks in an extreme case, its performance cannot be maintained, airtightness may be lost, and lack of elasticity and mechanical strength may cause problems. .

  On the other hand, in order to improve the heat resistance (compression set at high temperature) of a butyl rubber sealant, a method of adding a styrene thermoplastic elastomer or a thermoplastic resin to the butyl rubber sealant (see Patent Document 1) has been proposed. . In addition, two polymer blocks A made of vinyl aromatic compound, one polymer block B made of conjugated diene, and 80% or more of carbon-carbon double bonds derived from the conjugated diene are hydrogenated. A block copolymer having at least one block, wherein the content of the structural unit derived from the vinyl aromatic compound is 10 to 50% by mass, and the number average molecular weight is 250,000 or more, 100 parts by weight of the block copolymer, A thermoplastic polymer composition comprising 50 to 300 parts by weight of a non-aromatic rubber softener and 10 to 100 parts by weight of a polyethylene resin has been proposed as a thermoplastic polymer composition having improved heat resistance ( Patent Document 2).

Further, the polymer block is composed of three polymer blocks, and the polymer blocks at both ends of the three polymer blocks are polymer blocks mainly composed of a vinyl aromatic compound and are in the middle of the polymer blocks at both ends. A hydrogenated block copolymer obtained by hydrogenating a block copolymer, which is a polymer block mainly composed of a conjugated diene compound, measured by a gel permeation chromatography (GPC) method 100 parts by weight of a hydrogenated block copolymer having a weight average molecular weight of 250,000 or more, 60 to 170 parts by weight of a non-aromatic rubber softener having a kinematic viscosity at 40 ° C. of 300 to 500 mm ² / sec, and crystallinity Disclosed is a method for producing a thermoplastic elastomer composition comprising dry blending 5 to 30 parts by weight of polyolefin and then kneading. The resulting thermoplastic elastomer composition has few low molecular weight components and oil bleed, is low in hardness, has a low compression set, and is suitable for use in the construction of gaskets for hard disk devices and elastic members for ink jet recording devices. (See Patent Document 3).

  A hot melt composition comprising a hydrogenated paraffinic process oil, a high molecular weight styrene block copolymer, a polyphenylene ether resin or a modified polyphenylene ether resin, an antioxidant, and an amorphous polyalphaolefin. Disclosed, the hot melt composition has sufficient adhesion to a hardly adhesive polyolefin resin material, does not deteriorate even when placed under high temperature, and has excellent adhesion, sealing properties, etc. It is said that there is demolition. Here, as the high molecular weight styrene block copolymer, those having a number average molecular weight of 100,000 or more are suitable, and commercially available products include Septon 4055 manufactured by Kuraray Co., Ltd. (see Patent Document 4). ).

US Published Patent Publication No. 2003/0195287 JP 2001-240720 A JP 2002-226666 A JP 2005-97360 A

However, in the sealants using the conventional styrene-based thermoplastic elastomers and thermoplastic resins described in Patent Documents 1 to 4, vibration damping properties and oxygen gas barrier properties are reduced as compared with conventional butyl rubber-based sealants. There is still room for improvement.
An object of the present invention is a thermoplastic elastomer composition having improved flexibility, workability, heat resistance (compression set at high temperature), vibration damping properties, and oxygen gas barrier properties as compared with conventional butyl rubber sealants. It is to provide a hot melt sealant.

  As a result of intensive studies to solve the above problems, the present inventors have determined that a thermoplastic elastomer composition containing a specific styrene-based hydrogenated block copolymer and a softening agent, and if necessary, a tackifying resin in a specific ratio The present inventors have found that the above problems can be solved by a hot-melt sealant made of a product, and have completed the present invention based on these findings.

That is, the present invention includes a polymer block comprising a structural unit derived from an aromatic vinyl compound (A), it consists of structural units derived from isoprene emission, containing a 3,4-bond unit and 1,2-bond units A hydrogenated product of a block copolymer having a polymer block (B) having a total amount of 45% or more, and having a peak top molecular weight (Mp) of 250 calculated in terms of standard polystyrene by gel permeation chromatography. Thermoplastic elastomer containing hydrogenated block copolymer (a) and softener (b) in the form of powder having a bulk density of 0.10 to 0.40 g / ml A hot melt sealant comprising the composition.

  In a preferred embodiment, the thermoplastic elastomer composition constituting the hot melt sealant further contains a tackifying resin (c).

  In a preferred embodiment, the thermoplastic elastomer composition constituting the hot melt sealant further contains a polyphenylene ether resin (d).

  In a preferred embodiment, the thermoplastic elastomer composition constituting the hot melt sealant further contains a filler (e).

  According to the present invention, it comprises a thermoplastic elastomer composition having improved flexibility, workability, heat resistance (compression set at high temperature), vibration damping properties and oxygen gas barrier properties as compared with conventional butyl rubber sealants. A hot melt sealant can be provided.

  The hot melt sealant of the present invention comprises a thermoplastic elastomer composition containing a hydrogenated block copolymer (a) and a softening agent (b), and the thermoplastic elastomer composition is further tackified as necessary. Resin (c), polyphenylene ether resin (d), and filler (e) are contained. Hereinafter, each component will be described in detail.

[Hydrogenated block copolymer (a)]
The hydrogenated block copolymer (a) used in the present invention comprises a polymer block (A) composed of a structural unit derived from an aromatic vinyl compound and a structural unit derived from isoprene or a mixture of isoprene and butadiene. , 4-bond unit and 1,2-bond unit content (total vinyl bond content) is a hydrogenated block copolymer having a polymer block (B) of 45% or more. The peak top molecular weight (Mp) determined by gel permeation chromatography in terms of standard polystyrene is in the range of 250,000 to 500,000, and the bulk density is 0.10 to 0.40 g / ml in powder form. is there.

  The polymer block (A) of the hydrogenated block copolymer (a) is mainly composed of structural units (aromatic vinyl compound units) derived from an aromatic vinyl compound. Here, “mainly” means that the aromatic vinyl compound unit is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 100% by mass based on the mass of the polymer block (A). Means that.

  Examples of the aromatic vinyl compound constituting the polymer block (A) include styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, Examples include 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, vinylnaphthalene, and vinylanthracene. The polymer block (A) may contain only a structural unit derived from one kind of the above-described aromatic vinyl compound, or may contain a structural unit derived from two or more kinds. Among them, the polymer block (A) is preferably mainly composed of structural units derived from styrene.

  The polymer block (A) may contain a small amount of a structural unit derived from another copolymerizable monomer together with a structural unit derived from an aromatic vinyl compound. At this time, the proportion of the structural unit derived from the other copolymerizable monomer is preferably less than 10% by mass based on the mass of the polymer block (A), and more preferably less than 5% by mass. preferable. Examples of other copolymerizable monomers include ionic polymerizable monomers such as 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether. The bonding form of units based on these other copolymerizable monomers may be any form such as random or tapered.

  The polymer block (B) of the hydrogenated block copolymer (a) is suitably composed of a structural unit derived from isoprene alone or a mixture of isoprene and butadiene. When other conjugated dienes are used, for example, in the case of butadiene alone, even if the content of 1,2-bond units is increased, vibration damping, fluidity, oxygen gas barrier properties, and compression set at high temperature are improved. There is little practical significance. In this specification, 3,4-bond units and 1,2-bond units in structural units derived from isoprene, and 1,2-bond units in structural units derived from butadiene are referred to as vinyl bond units, and the total The amount is referred to as vinyl bond content.

When the polymer block (B) is composed only of a structural unit derived from isoprene, the structural unit is a 2-methyl-2-butene-1,4-diyl group [—CH ₂ —C (CH ₃ ) ═CH—. CH ₂ -; 1,4-bond unit, isopropenyl ethylene group _{[-CH (C (CH 3)} = CH 2) -CH 2 -; 3,4- bond unit] and 1-methyl-1-vinyl ethylene Group [—C (CH ₃ ) (CH═CH ₂ ) —CH ₂ —; 1,2-linkage unit], and in the present invention, its vinyl bond content (3,4-linkage unit and 1,2 bond unit) -The sum of the content of bond units) is 45% or more. The vinyl bond content is more preferably 47% or more, and further preferably 50% or more. Although there is no restriction | limiting in particular in the upper limit of vinyl bond content, Usually, it is 95% or less, and it is more preferable that it is 90% or less.

When the polymer block (B) is composed of a structural unit derived from a mixture of isoprene and butadiene, the structural unit is a 2-methyl-2-butene-1,4-diyl group or isopropenyl derived from isoprene. Ethylene group and 1-methyl-1-vinylethylene group, and 2-butene-1,4-diyl group derived from butadiene [—CH ₂ —CH═CH—CH ₂ —; 1,4-bond unit] and vinyl An ethylene group [—CH (CH═CH) —CH ₂ —; 1,2-bond unit], and a vinyl bond content (3,4-bond units and 1,2-bond units derived from isoprene and The total content of 1,2-bond units derived from butadiene is 45% or more. The vinyl bond content is more preferably 47% or more, and further preferably 50% or more. Although there is no restriction | limiting in particular in the upper limit of vinyl bond content, Usually, it is 95% or less, and it is more preferable that it is 90% or less. In the copolymer block, the arrangement of the structural unit derived from isoprene and the structural unit derived from butadiene may be random, block, or tapered.

  When the polymer block (B) is composed of a structural unit derived from a mixture of isoprene and butadiene, from the viewpoint of maintaining good oxygen gas barrier properties, vibration damping properties, and fluidity of the thermoplastic elastomer composition obtained in the present invention, The molar ratio of isoprene unit / butadiene unit is preferably 10/90 or more, more preferably 30/70 or more, and further preferably 40/60 or more.

  The polymer block (B) has a small amount of structural units derived from other copolymerizable monomers together with structural units derived from isoprene or isoprene and butadiene within the range not impairing the object of the present invention. May be. At this time, the proportion of the structural unit derived from the other copolymerizable monomer is preferably less than 30% by mass based on the mass of the polymer block (B), and more preferably less than 10% by mass. preferable.

  Examples of other copolymerizable monomers include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, diphenylethylene, 1-vinylnaphthalene, Examples thereof include anion polymerizable monomers such as aromatic vinyl compounds such as 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene. These other copolymerizable monomers can be used alone or in combination of two or more. When the polymer block (B) has a structural unit derived from another copolymerizable monomer such as an aromatic vinyl compound in addition to the structural unit derived from isoprene or isoprene and butadiene, the bonding form thereof is random, Any of tapered shapes may be used.

The hydrogenated block copolymer (a) used in the present invention has an unsaturated double bond (carbon-carbon double bond) in the polymer block (B) from the viewpoint of good heat resistance and weather resistance. It is preferable that a part or all of () is hydrogenated. The hydrogenation rate of the polymer block (B) at that time is preferably 50 mol% or more, more preferably 60 mol% or more, and further preferably 70 mol% or more.
In addition, the hydrogenation rate of the unsaturated double bond in the polymer block (B) is determined based on the content of the unsaturated double bond in the polymer block (B) by the iodine value measurement, infrared spectroscopy before and after the hydrogenation. It can be determined from the measured value by measuring with a photometer (IR), nuclear magnetic resonance ( ¹ H-NMR) or the like.

  The hydrogenated block copolymer (a) may contain a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an epoxy group, etc. in the molecular chain and / or at the molecular end, as long as the gist of the present invention is not impaired. You may have 1 type, or 2 or more types of a functional group.

The hydrogenated block copolymer (a) is a hydrogenated product of a block copolymer containing at least one polymer block (A) and each polymer block (B). Preferably, the hydrogenated block copolymer (a) is a hydrogenated product of a block copolymer containing two or more polymer blocks (A) and one or more polymer blocks (B). The bonding form of the polymer block (A) and the polymer block (B) is not particularly limited, and may be any of linear, branched, radial, or a combination of two or more thereof. However, when the polymer block (A) is represented by A and the polymer block (B) is represented by B, (A-B) l, A- (B-A) m, B- (A-B) n (wherein l, m and n each independently represents an integer of 1 or more) is preferably a bonded form, and viewpoints such as rubber elasticity, mechanical properties and handleability From the above, it is particularly preferable to be a bonded form of a diblock structure represented by AB or a triblock structure represented by ABA.
When the hydrogenated block copolymer (a) has two or more polymer blocks (A) or two or more polymer blocks (B), each polymer block (A) and each polymer block (A) The combined block (B) may be a block having the same configuration or a block having a different configuration. For example, in the two polymer blocks (A) in the triblock structure represented by [ABA], the types of the aromatic vinyl compounds constituting them may be the same or different. Good.

The content of the polymer block (A) is preferably in the range of 5 to 70% by mass and more preferably in the range of 15 to 50% by mass with respect to the hydrogenated block copolymer (a). When the content of the polymer block (A) is in the above range, the resulting thermoplastic elastomer composition is excellent in rubber elasticity and flexibility. The content of the polymer block (A) in the hydrogenated block copolymer (a) can be determined from a ¹ H-NMR spectrum or the like.

In the hydrogenated block copolymer (a), the peak top molecular weight of the polymer block (A) is preferably 10,000 to 60,000, more preferably 15,000 to 45,000. The peak top molecular weight of the polymer block (B) is preferably 130,000 to 450,000, more preferably 180,000 to 430,000 in the state before hydrogenation.
Moreover, the peak top molecular weight (Mp) of the whole hydrogenated block copolymer (a) is 250,000-500,000 in the state after hydrogenation, and it is more preferable that it is 310,000-500,000. preferable. When the peak top molecular weight (Mp) of the hydrogenated block copolymer (a) is within the above range, the powdered hydrogenated block copolymer having a bulk density of 0.10 to 0.40 g / ml ( a) is easily obtained, and the block copolymer (a) is excellent in the absorbability of the softener (b). Furthermore, the obtained thermoplastic elastomer composition is excellent in compression set at a high temperature and retention of the softening agent (b).
In addition, the peak top molecular weight (Mp) as used in this specification is the value calculated | required by standard polystyrene conversion by the gel permeation chromatography (GPC) method.

<Production of hydrogenated block copolymer (a)>
From the viewpoint of absorbability of the softening agent (b), it is important that the hydrogenated block copolymer (a) is in the form of a powder having a bulk density of 0.10 to 0.40 g / ml. More preferably within the range of ˜0.35 g / ml. When the bulk density is less than 0.10 g / ml, the handleability is deteriorated, and when it exceeds 0.40 g / ml, the absorbability of the softener (b) is deteriorated. The bulk density referred to in the present specification was calculated by placing a weighed powdered hydrogenated block polymer (a) in a graduated cylinder, measuring its volume, and dividing the mass of the polymer by the volume. Value.

  Examples of the method for producing the hydrogenated block copolymer (a) include polymerization methods such as ionic polymerization methods such as anionic polymerization and cationic polymerization, single site polymerization methods, and radical polymerization methods. In the case of the anionic polymerization method, for example, an aromatic vinyl compound, a conjugated diene compound (isoprene, or isoprene and butadiene is used in an inert organic solvent such as n-hexane or cyclohexane using an alkyl lithium compound as a polymerization initiator. A block copolymer having a desired molecular structure and molecular weight, and then adding an active hydrogen compound such as alcohols, carboxylic acids and water to stop the polymerization. Coalescence can be produced. Then, the hydrogenated block copolymer (a) can be obtained by conducting a hydrogenation reaction in the presence of a hydrogenation catalyst in an inert organic solvent without preferably isolating the obtained block copolymer. it can.

  Examples of the alkyl lithium compound include alkyl lithium compounds having 1 to 10 carbon atoms in the alkyl residue, and methyl lithium, ethyl lithium, butyl lithium, and pentyl lithium are particularly preferable. The amount of the initiator such as an alkyl lithium compound used is determined by the peak top molecular weight (Mp) of the desired hydrogenated block copolymer (a). On the other hand, the initiator is generally used in the range of 0.01 to 0.2 parts by mass.

  The polymerization is usually carried out in the temperature range of 0 to 80 ° C. for 0.5 to 50 hours.

  In the polymer block (B) of the hydrogenated block copolymer (a), the structural unit composed of isoprene or a mixture of isoprene and butadiene has a vinyl bond content (3,4-bond units and 1, In order to obtain a total of 2-bond units, a Lewis base is used as a cocatalyst during polymerization. Examples of the Lewis base include ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran, glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, triethylamine, N, N, N ′, N′-tetramethylenediamine, and N-methylmorpholine. These amine compounds can be mentioned. The amount of these Lewis bases used is generally in the range of 0.1 to 1000 times the number of moles of lithium of the alkyl lithium compound used as the initiator.

  In the hydrogenation reaction, an unhydrogenated block copolymer was dissolved in an inert organic solvent such as n-hexane or cyclohexane which is inert to the reaction and the hydrogenation catalyst in the presence of the hydrogenation catalyst. In this state, a method of reacting molecular hydrogen is preferably used. In addition, it is also possible to subject the reaction liquid obtained by sequentially copolymerizing an aromatic vinyl compound and isoprene (or a mixture of isoprene and butadiene) to a hydrogenation reaction as it is. Examples of hydrogenation catalysts include Raney nickel; heterogeneous catalysts such as Pt, Pd, Ru, Rh, Ni and other metals supported on carbon, alumina, diatomaceous earth, etc .; transition metal compounds and alkylaluminum compounds, alkyllithiums A Ziegler-based catalyst composed of a combination of compounds is used. The reaction is usually carried out at a hydrogen pressure of 0.1 to 20 MPa, a reaction temperature of 20 ° C. to 250 ° C., and a reaction time of 0.1 to 100 hours.

  The hydrogenated block copolymer (a) having a powder shape with a bulk density of 0.10 to 0.40 g / ml defined in the present invention can be produced, for example, by the following method. The reaction solution from which the hydrogenation catalyst has been removed by filtration after the above hydrogenation reaction is heated to 40 to 150 ° C., preferably 60 to 150 ° C., and a surfactant such as a fatty acid salt or a polyoxyalkylene derivative is mixed as necessary. In this state, it is supplied into hot water at 80 to 130 ° C. at a rate of 100 parts by mass / hour, and at the same time, 1 MPa of steam is supplied at a rate of 40 to 60 parts by mass / hour to inactivate saturated hydrocarbons, etc. When the boiling point of the organic solvent or the inert organic solvent and water is azeotroped, steam stripping is performed at a temperature not lower than the azeotropic temperature and not higher than 150 ° C., and the moisture content is 55 mass% / WB (wet) with a compressed water squeezer. Base, the same shall apply hereinafter), preferably 45% by mass / WB or less, using a screw extruder dryer, expander dryer, conduction heat transfer dryer, hot air dryer, etc. By drying at 0 to 100 ° C., it can be produced hydrogenated block copolymer (a) having a water content of 0.1 wt% / WB less desired powder form.

[Softener (b)]
The thermoplastic elastomer composition used in the present invention contains a softening agent (b) for the purpose of imparting flexibility, moldability and the like. Examples of the softener (b) include paraffinic, naphthenic, and aromatic process oils; phthalic acid derivatives such as dioctyl phthalate and dibutyl phthalate; white oil; mineral oil; liquid co-oligomer of ethylene and α-olefin Liquid paraffin; polybutene; low molecular weight polyisobutylene; liquid polybutadiene, liquid polyisoprene, liquid polyisoprene / butadiene copolymer, liquid styrene / butadiene copolymer, liquid polydiene such as liquid styrene / isoprene copolymer and hydrogenation thereof Such as things. Among these, from the viewpoint of compatibility with the hydrogenated block copolymer (a), paraffinic process oil; liquid co-oligomer of ethylene and α-olefin; liquid paraffin is preferable.

  The content of the softening agent (b) is preferably in the range of 10 to 500 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (a), and from the viewpoint of moldability, 50 to 400 parts by mass. More preferably, it is the range.

[Tackifying resin (c)]
If necessary, the thermoplastic elastomer composition used in the present invention can contain a tackifier resin (c) as long as the gist of the present invention is not impaired. As the tackifying resin (c), those conventionally used as a resin imparting tackiness can be used without particular limitation. For example, rosin resins such as gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, glycerin esters, pentaerythritol esters and other rosin esters; α-pinene, β-pinene, dipentene, etc. Terpene resins such as terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins, etc .; (hydrogenated) aliphatic (C5) petroleum resins, (hydrogenated) aromatic (C9) ) Petroleum resins that may be hydrogenated, such as petroleum resins, (hydrogenated) copolymerized (C5 / C9) petroleum resins, (hydrogenated) dicyclopentadiene-based petroleum resins, alicyclic saturated hydrocarbon resins, Poly α-methylstyrene, α-methylstyrene / styrene copolymer, styrene monomer / aliphatic monomer copolymer, styrene monomer α-Methylstyrene / aliphatic monomer copolymer, styrene monomer copolymer, styrene resin such as styrene monomer / aromatic monomer copolymer other than styrene monomer, phenol resin, xylene resin, coumarone Examples thereof include synthetic resins such as indene resins. Among these, hydrogenated terpene resins, alicyclic saturated hydrocarbon resins, and aliphatic petroleum resins are preferable from the viewpoint of suppressing coloring of the thermoplastic elastomer composition. These may be used alone or in combination of two or more. When the tackifier resin (c) is contained, the amount thereof is preferably in the range of 10 to 300 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (a), and from the viewpoint of heat resistance, 50 to A range of 250 parts by mass is more preferable. In addition, about the softening point of tackifying resin, the thing of 50 to 150 degreeC is preferable from a heat resistant viewpoint, and 100 to 150 degreeC is more preferable.

[Polyphenylene ether resin (d)]
The thermoplastic elastomer composition used in the present invention may further contain a polyphenylene ether resin (d) for the purpose of improving heat resistance (compression set at high temperature). As the polyphenylene ether resin (d), for example, a polymer represented by the following general formula (1) can be used.

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group, a substituted hydrocarbon group, an alkoxy group, a cyano group, a phenoxy group or a nitro group. , M is a positive integer representing the degree of polymerization.)

In the preferred polyphenylene ether resin (d), R ¹ and R ² in the above formula (1) are alkyl groups, particularly alkyl groups having 1 to 4 carbon atoms, and R ³ and R ⁴ are hydrogen atoms or carbon atoms. It is a C 1-4 alkyl group. m is usually preferably 50 or more. Examples of the polyphenylene ether resin (d) include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, and poly (2-methyl-6). -Ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenylene) ether, poly (2,6-dipropyl-1,4-phenylene) ether, poly (2-ethyl) -6-propyl-1,4-phenylene) ether, poly (2,6-dimethoxy-1,4-phenylene) ether, poly (2,6-dichloromethyl-1,4-phenylene) ether, poly (2, 6-dibromomethyl-1,4-phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2,6-ditolyl-1,4-phen) Len) ether, poly (2,6-dichloro-1,4-phenylene) ether, poly (2,6-dibenzyl-1,4-phenylene) ether, poly (2,5-dimethyl-1,4-phenylene) Examples include ether. Among them, a particularly preferable polyphenylene ether resin (d) is poly (2,6-dimethyl-1,4-phenylene) ether. These may be modified with a modifying agent having a polar group. Examples of polar groups include acid halides, carbonyl groups, acid anhydrides, acid amides, carboxylic acid esters, acid azides, sulfone groups, nitrile groups, cyano groups, isocyanate esters, amino groups, imide groups, hydroxyl groups, and epoxy groups. , An oxazoline group, a thiol group, and the like.

The polyphenylene ether resin (d) used in the present invention is preferably in the range of 1,000 to 100,000 as the number average molecular weight, and particularly in the range of 6,000 to 60,000 in consideration of the balance of various physical properties. More preferably.
In the case where the thermoplastic elastomer composition used in the present invention contains the polyphenylene ether resin (d), from the viewpoint of flexibility, the thermoplastic elastomer composition is in a range of 20 parts by mass or less with respect to 100 parts by mass of the entire thermoplastic elastomer composition. Preferably there is.

[Filler (e)]
If necessary, the thermoplastic elastomer composition used in the present invention can further contain a filler (e) as long as the gist of the present invention is not impaired. Examples of the filler (e) include calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, magnesium carbonate, glass fiber, and carbon fiber.
When the thermoplastic elastomer composition used in the present invention contains the filler (e), from the viewpoint of maintaining flexibility and low rebound resilience, 10 to 500 masses with respect to 100 mass parts of the entire thermoplastic elastomer composition. Part range is preferable, and a range of 20 to 300 parts by mass is more preferable.

[Other additives; Polyolefin resin]
From the viewpoint of improving moldability and the like, the thermoplastic elastomer composition used in the present invention may further contain a polyolefin resin. Examples of such polyolefin resins include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and the like, homopolymers of propylene such as homopolypropylene, and block copolymers of propylene and ethylene (block polypropylene). Or a random copolymer (random polypropylene), a copolymer of propylene or ethylene and an α-olefin, and the like can be given. Examples of the α-olefin include 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-heptene, Examples include α-olefins having 20 or less carbon atoms such as octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and one or two of these The above can be used.

  When the polyolefin resin is further contained, the amount thereof is preferably in the range of 5 to 200 parts by mass, and in the range of 10 to 180 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (a). Is more preferable, and it is still more preferable that it is the range of 20-150 mass parts. When the content of the polyolefin resin is less than 5 parts by mass, the mechanical strength of the obtained thermoplastic elastomer composition may be lowered. When the content exceeds 200 parts by mass, the hardness of the obtained thermoplastic elastomer composition becomes high and flexible. In some cases, the compression set at a high temperature is inferior.

[Other additives; lubricants, crosslinking agents, stabilizers, pigments, etc.]
The thermoplastic elastomer composition used in the present invention may contain various additives as necessary as long as the gist of the present invention is not impaired. Examples of such additives include lubricants, antioxidants, heat stabilizers, light stabilizers, weathering agents, metal deactivators, ultraviolet absorbers, light stabilizers, copper damage inhibitors, crosslinking agents, crosslinking aids, and reinforcing agents. Antistatic agent, antibacterial agent, antifungal agent, dispersant, colorant, rubber such as isobutylene / isoprene copolymer, silicone rubber, thermoplastic resin such as ethylene / vinyl acetate copolymer, ABS resin, etc. Can be mentioned.

  Among them, the lubricant has an action of improving the fluidity of the thermoplastic elastomer composition and suppressing thermal degradation. Examples of the lubricant that can be used in the present invention include silicone oils; hydrocarbon lubricants such as paraffin wax, microwax, polyethylene wax; butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, stearyl stearate, and the like. It is done.

  The thermoplastic elastomer composition used in the present invention may be crosslinked using an organic peroxide or the like, if necessary, as long as the gist of the present invention is not impaired. In this case, a crosslinking aid can be used in combination.

[Manufacture of hot melt sealant comprising thermoplastic elastomer composition]
The method for producing the thermoplastic elastomer composition used in the present invention is not particularly limited. For example, a hydrogenated block copolymer (a) and a softening agent (b), and if necessary, a tackifying resin (c), a polyphenylene ether type Resin (d), filler (e), polyolefin resin and additives are pre-blended and mixed together, then melted using a single screw extruder, multi screw extruder, Banbury mixer, Brabender, open roll, kneader, etc. Kneading method, hydrogenated block copolymer (a), softener (b) and, if necessary, tackifying resin (c), polyphenylene ether resin (d), filler (e), polyolefin resin, additive And a method of melting and kneading by supplying them from separate charging ports. Examples of the pre-blending method include a method using a mixer such as a Henschel mixer, a high speed mixer, a V blender, a ribbon blender, a tumbler blender, or a conical blender.
The thermoplastic elastomer composition thus obtained can be used as it is as the hot melt sealant of the present invention.

  The method for applying the hot melt sealant of the present invention is not particularly limited. For example, hand gun type, block melt type, bulk type and foam type hot melt coating apparatuses can be used.

  The hot melt sealant of the present invention has fluidity (MFR) because the hydrogenated block copolymer (a), which is an essential component constituting the thermoplastic elastomer composition as the component, is excellent in the absorbability of the softener (b). ) Is excellent in molding processability and excellent in handleability during melt kneading. Further, it is excellent in flexibility, vibration damping properties, softener retention, high temperature compression set, and has a good balance of these properties.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples. The physical properties in Reference Examples, Examples and Comparative Examples were evaluated by the following methods.

(1) Content of polymer block (A) The block copolymer (a) after hydrogenation was dissolved in CDCl ₃ and ¹ H-NMR spectrum was measured (apparatus: JNM-Lambda 500 (JEOL Ltd.) And the content of the polymer block (A) was calculated from the peak intensity derived from styrene.

(2) Peak top molecular weight (Mp)
The peak top molecular weight (Mp) in terms of polystyrene was determined for the polymer block (A) before hydrogenation and the hydrogenated block copolymer (a) after hydrogenation by gel permeation chromatography (GPC) measurement.
Equipment: Gel permeation chromatograph “HLC-8020” manufactured by Tosoh Corporation
Column: G4000HXL x 2 (Tosoh Corporation)
Eluent: Tetrohydrofuran, flow rate: 1 ml / min Injection volume: 150 μl
Concentration: 5 mg / 10 ml (block copolymer / tetrohydrofuran),
Column temperature: 40 ° C
Calibration curve: Prepared using standard polystyrene Detection method: Differential refractive index (RI)

(3) Hydrogenation rate of hydrogenated block copolymer (a) The iodine value of the block copolymer before and after hydrogenation was measured, and the hydrogenation rate (%) of the hydrogenated block copolymer (a) was determined from the measured value. ) Was calculated.

Hydrogenation rate (%) = {1− (iodine value of block copolymer after hydrogenation / iodine value of block copolymer before hydrogenation)} × 100

(4) Vinyl bond content of polymer block (B) of hydrogenated block copolymer (a) The block copolymer before hydrogenation was dissolved in CDCl ₃ and ¹ H-NMR spectrum was measured (apparatus: JNM -Lambda 500 (manufactured by JEOL Ltd., measurement temperature: 50 ° C.), and the total peak area of structural units derived from isoprene, butadiene, or a mixture of isoprene and butadiene, 1,2-bond units in isoprene structural units and In the case of a 3,4-bond unit, a 1,2-bond unit in a butadiene structural unit, or a mixture of isoprene and butadiene, the vinyl bond content (1,2- The sum of the content of bond units and 3,4-bond units) was calculated.

(5) Bulk density By weighing the powdered hydrogenated block copolymer (a) into a measuring cylinder and measuring its volume, the mass of the hydrogenated block copolymer (a) is divided by the volume. Calculated.

(6) Hardness The thermoplastic elastomer compositions obtained in the following Examples and Comparative Examples were hot press-molded at 230 ° C. and 10 MPa for 3 minutes using a press molding machine to obtain a length of 50 mm × width A sheet-like test piece of 50 mm × thickness 2 mm was obtained. Using this test piece, the Type-C hardness was measured according to SRIS0101-1968, and used as an index of flexibility.

(7) MFR
The thermoplastic elastomer compositions obtained in the following examples and comparative examples were measured in accordance with JIS K 7210, and the weight of the thermoplastic elastomer composition discharged from the capillary per unit time was measured. did. The measurement temperature was 200 ° C. and the load was 21.2 N. The higher the MFR value, the better the flow and the better the workability.

(8) Rebound resilience (damping property)
The thermoplastic elastomer compositions obtained in the following Examples and Comparative Examples were compression molded at 200 ° C. for 3 minutes using a compression molding machine, diameter 29.0 ± 0.5 mm, thickness 12.5 ± 0.00. A 5 mm cylindrical test piece was prepared. Using this test piece, the rebound resilience at 25 ° C. was measured with a Lüpke-type rebound resilience tester in accordance with JIS K 6255. The smaller the value of the impact resilience, the better the vibration damping.

(9) Compression set The thermoplastic elastomer compositions produced in the following examples and comparative examples were compression molded at 200 ° C. for 3 minutes using a compression molding machine, diameter 13.0 ± 0.5 mm, thickness 6.3 ±. A 0.3 mm cylindrical test piece was prepared. Using this cylindrical test piece, the compression set after maintaining 25% compression deformation for 22 hours at two temperatures of 70 ° C. and 100 ° C. was measured in accordance with JIS K 6262. The smaller this value, the better the compression set at a high temperature.

(10) Oxygen transmission coefficient (OTR)
Based on JIS K7126-1 (differential pressure method), the oxygen permeability coefficient (ml · 20 μm / m ² · day · atm) was measured by a differential pressure type gas chromatography method. The thermoplastic elastomer compositions obtained in the following examples and comparative examples were compression molded at 230 ° C. for 2 minutes using a compression molding machine to produce a film-shaped test piece having a thickness of 300 μm. Using a transmittance measuring device (“GTR-10” manufactured by Yanagimoto Seisakusho), measurement was performed at an oxygen pressure of 0.25 MPa, a measurement temperature of 35 ° C., and a measurement humidity of 0% RH. A smaller OTR value indicates a higher oxygen gas barrier property.

Reference Example 1 (Production of hydrogenated block copolymer (a) -1)
1.84 kg of styrene and 55.8 kg of cyclohexane as a solvent were charged in a pressure-resistant container substituted with dry nitrogen. To this solution, 45 ml of sec-butyllithium (10% by mass, cyclohexane solution) was added as an initiator and polymerized at 60 ° C. for 1 hour. Next, after adding 305 g of tetrahydrofuran as a Lewis base to this reaction mixture, 8.57 kg of isoprene was added and polymerization was performed for 2 hours, and further 1.84 kg of styrene was added and polymerization was performed for 1 hour to obtain polystyrene-polyisoprene-polystyrene. A reaction solution containing a triblock copolymer was obtained. After sampling a very small amount for analysis, 5% by mass of palladium carbon (palladium supported amount: 5% by mass) as a hydrogenation catalyst was added to the copolymer, and the hydrogen pressure was 2 MPa and 150 ° C. The reaction was carried out for 5 hours under the following conditions. After cooling and releasing the pressure, palladium carbon was removed by filtration, and then the filtrate was heated again to 80 ° C. and supplied to hot water at 110 ° C. at a rate of 100 kg / hour. At the same time, 1 MPa steam was supplied at a rate of 50 kg / hour, and steam stripping was performed at a temperature in the reaction vessel of 110 ± 2 ° C. The obtained slurry was dehydrated to 45% with a compressed water squeezer, dried by heating with a plate dryer at 120 ° C., and a powdery polystyrene-polyisoprene-polystyrene triblock copolymer having a water content of 0.1% by mass. The hydrogenated product (hereinafter referred to as hydrogenated block copolymer (a) -1) was obtained. The resulting hydrogenated block copolymer (a) -1 has a hydrogenation rate of 97.2%, the content of the polymer block (A) is 29.4% by mass, and the peak top of the polymer block (A). The molecular weight is 37,500, the peak top molecular weight (Mp) of the hydrogenated block copolymer is 315,000, the vinyl bond content of the polymer block (B) is 55.2%, and the bulk density is 0.22 g / ml. there were.

Reference Example 2 (Production of hydrogenated block copolymer (a) -2)
In Reference Example 1, 55.8 kg of cyclohexane as a solvent, 53 ml of sec-butyllithium (10% by mass, cyclohexane solution) as an initiator, 1.59 kg of styrene as a monomer to be polymerized without adding a Lewis base, a mixture of isoprene and butadiene [Isoprene / butadiene = 55/45 (molar ratio)] 7.44 kg and 1.59 kg of styrene were successively added and polymerized in the same manner as in Reference Example 1, polymerization reaction, hydrogenation reaction, decatalyst and drying. Then, a hydrogenated product of polystyrene-poly (isoprene / butadiene) -polystyrene triblock copolymer was obtained (hereinafter referred to as hydrogenated block copolymer (a) -2). The hydrogenated block copolymer (a) -2 obtained had a hydrogenation rate of 98.9%, the polymer block (A) content was 29.4% by mass, and the peak top of the polymer block (A). The molecular weight is 27,500, the peak top molecular weight (Mp) of the hydrogenated block copolymer (a) -2 is 303,000, the vinyl bond content of the polymer block (B) is 8.1%, and the bulk density is 0. 0.22 g / ml.

Examples 1-5 and Comparative Examples 1-5
Each component shown in Table 1 was mixed at 200 to 230 ° C. for 2 hours using a sigma blade type kneader according to the formulation shown in Table 1 to prepare a hot melt sealant composed of a thermoplastic elastomer composition. Using the obtained thermoplastic elastomer composition, MFR was measured by the above method, and each test piece was prepared by the above method, and by the above method, hardness, compression set, rebound resilience, oxygen permeability coefficient Was measured. The results are shown in Table 1.

Each component described in Table 1 is as follows.
Softener (b): Diana process oil PW-90 (hydrogenated paraffin oil, manufactured by Idemitsu Kosan Co., Ltd.)
・ Tackifying resin (c): hydrogenated alicyclic hydrocarbon resin; manufactured by ExxonMobil, trade name “Escollets ECR-227E”
-Polyphenylene ether resin (d): Modified polyphenylene ether resin; manufactured by Asahi Kasei Chemicals, trade name "Zylon 500H"
-Filler (e) -1: Heavy calcium carbonate; Sankyo Seimitsu Co., Ltd., trade name "ESCALON 200"
Filler (e) -2: Glass hollow sphere powder; manufactured by 3M, trade name “Glass Bubbles K-37”
Polyolefin resin: Homopolypropylene; manufactured by Nippon Polypro Co., Ltd., trade name “NOVATEC PP MA3”, MFR = 10 g / 10 min
Antioxidant-1: hindered phenol antioxidant; manufactured by Ciba Specialty Chemicals, trade name “Irganox 1010”
-Antioxidant-2: Phosphorous antioxidant; manufactured by Ciba Specialty Chemicals, trade name "Irgaphos 168"

  From Table 1, the thermoplastic elastomer compositions obtained in Examples 1 to 5 are low in hardness in comparison with the same composition as compared to the thermoplastic elastomer compositions obtained in Comparative Examples 1 to 5. From the values of compression set at 70 ° C. and 100 ° C., it is understood that the heat resistance is also excellent. Furthermore, the thermoplastic elastomer compositions obtained in Examples 1 to 5 have low impact resilience, excellent vibration damping properties, and excellent oxygen gas barrier properties. It turns out that it is hard to be done and is airtight.

  The hot melt sealant comprising the thermoplastic elastomer composition of the present invention has improved workability, heat resistance, vibration damping and oxygen gas barrier properties while maintaining flexibility. For example, it can be connected using a hand gun or the like. As an amorphous hot-melt sealant that seals in the gaps of parts, or by forming a string-like or seal-like molded sealant using extrusion molding or injection molding, for example, equipment around automobile engines, solar It can be used for various applications such as using as a hot melt sealant at a joint of a device such as a battery panel.

Claims (4)

And a structural unit derived from an aromatic vinyl compound polymer block (A), consists of structural units derived from isoprene emissions, the total content of 3,4-bond unit and 1,2-bond units 45% A hydrogenated product of a block copolymer having the above polymer block (B) having a peak top molecular weight (Mp) of 250,000 to 500,000 determined by gel permeation chromatography in terms of standard polystyrene. And a hot melt comprising a thermoplastic elastomer composition containing a hydrogenated block copolymer (a) and a softening agent (b) in the form of a powder having a bulk density of 0.10 to 0.40 g / ml Sealant. The hot melt sealant according to claim 1, further comprising a thermoplastic elastomer composition containing a tackifying resin (c). The hot melt sealant according to claim 1 or 2, further comprising a thermoplastic elastomer composition containing a polyphenylene ether resin (d). The hot melt sealant according to claim 2 or 3 , further comprising a thermoplastic elastomer composition containing a filler (e).