Patent Description:
A self-adhesive agent refers to an adhesive agent that has low adhesive force with respect to another material when being stuck to the another material, but that exhibits strong adhesive force (self-adhesiveness) when adhesive surfaces of the self-adhesive agent are bonded together and pressure is applied thereto.

Such a self-adhesive agent does not require a device such as a heat sealer and a heat source, and is easy to work with. In addition, the self-adhesive agent does not require release paper for covering an adhesive surface thereof and a releasing treatment on a back surface of a tape. Based on these facts, self-adhesive agents are widely used in applications such as binding tapes for binding various articles (such as raw vegetables, raw flowers, documents, newspapers, and magazines), and adhesive-type envelopes.

In <CIT>, a solvent-type adhesive (adhesive tape) is disclosed as an adhesive having self-adhesive force greater than adhesive force to a SUS substrate. The solvent-type adhesive is obtained by applying, to the substrate, an adhesive solution containing fine particles having large particle diameters and an adhesive component such as a rubber-based adhesive, and drying the adhesive solution. However, such a solvent-type adhesive needs taking a time to dry the solvent after application. Therefore, it is not possible to increase productivity, and large-scale equipment such as a drying oven is required for production of the solvent-type adhesive. In addition, in a case where the solvent-type adhesive is used in a binding tape for binding vegetables and the like, a residual solvent sometimes poses a problem.

In recent years, in order to solve such problems to improve productivity and reduce a residual solvent, a hot melt-type self-adhesive agent which is of a solvent-free type and can be produced at high speed has been developed. <CIT> discloses a hot melt-type adhesive composition containing a styrene-diene-based block copolymer, a specific tackifier, an inorganic filler having a specific particle diameter, and a plasticizer. The adhesive composition has large self-adhesive force, low tack on the adhesive surface, and a little residual solvent.

Document <CIT> relates to polyolefin, adhesive compositions containing the same, and adhesive tape using said adhesive compositions. In the document <CIT>, hot melt adhesives containing phase changing materials are described. The document <CIT> describes polyethylene and propylene wax for hot melt adhesive.

However, the hot melt-type adhesive composition with a reduced residual solvent as disclosed in Patent Literature <NUM> has a problem that the inorganic filler obstructs a filter and an outlet of a coating machine, resulting in decreased productivity.

In view of the above circumstances, an object of an embodiment of the present invention is to provide an adhesive composition that does not contain a solvent and that is excellent in productivity and self-adhesiveness.

The problem is solved by an adhesive composition according to the independent claim <NUM>. Embodiments are the subject matter of dependent claims in the appended set of claims.

According to an embodiment of the present invention, it is possible to bring about an effect of providing an adhesive composition that does not contain a solvent and that is excellent in productivity and self-adhesiveness.

The following description will discuss an embodiment of the present invention. The present invention is, however, not limited to the embodiment below. The present invention is not limited to the arrangements described below, but may be altered in various ways by a skilled person within the scope of the claims. Any embodiment or working example based on a combination of technical means disclosed in different embodiments or Examples is also encompassed in the technical scope of the present invention. Further, it is possible to form a new technical feature by combining the technical means disclosed in the respective embodiments. Numerical expressions such as "A to B" herein indicate "not less (lower) than A and not more (higher) than B" unless otherwise stated.

The inventors of the present invention, as a result of diligent study in order to attain the above object, have found that, by using an olefin-based polymer as a raw material for an adhesive composition, it is possible to provide a self-adhesive composition that contains no solvent and that is excellent in productivity, without the use of an inorganic filler that causes obstruction in a coating device. As disclosed in <CIT>, in the conventional hot melt-type self-adhesive agent, an inorganic filler is blended in order to provide an adhesive composition having large self-adhesive force and low tack on the adhesive surface. The inventors of the present invention have used an olefin-based polymer as a raw material for an adhesive composition and found, surprisingly, that it is possible to provide, even without an inorganic filler blended, an adhesive composition having excellent self-adhesive force and having low adhesive force to another material when being stuck to the another material. Based on this finding, the inventors of the present invention have accomplished the present invention.

That is, an adhesive composition in accordance with an embodiment of the present invention is an adhesive composition containing an olefin-based polymer, in the adhesive composition, no inorganic particles being blended, and the adhesive composition having a storage modulus at <NUM> of <NUM> to <NUM>×<NUM><NUM> Pa, and a storage modulus at <NUM> of <NUM>×<NUM><NUM> Pa to <NUM>×<NUM><NUM> Pa.

According to the configuration, it is possible to provide a self-adhesive composition that does not contain a solvent and that is excellent in productivity.

The adhesive composition in accordance with an embodiment of the present invention includes an olefin-based polymer. Herein, the olefin-based polymer refers to a polymer obtained by polymerizing one or more types of olefins optionally with a monomer different from olefin. It can be said that the olefin-based polymer is a polymer containing a constituent (olefin component) derived from the olefin. The olefin-based polymer used in the present invention may contain a monomeric component other than the olefin component as a constituent. A proportion of the olefin component contained in the olefin-based polymer is preferably not less than <NUM>% by weight, and more preferably not less than <NUM>% by weight. The olefin-based polymer more preferably contains <NUM>% by weight of the olefin component. That is, the olefin-based polymer is preferably a polyolefin.

Examples of the olefin include, but not limited to, olefins having a carbon number of preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>. Specific examples of the olefin include ethylene, propylene, <NUM>-butene, <NUM>-butene, <NUM>-pentene, <NUM>-pentene, <NUM>-methyl-<NUM>-pentene, <NUM>-hexene, <NUM>-octene, <NUM>-nonene, <NUM>-decene, and the like. The olefin-based polymer may be a homopolymer of any of these olefins, or may be a copolymer containing at least two types of olefins selected from these olefins. Among those, the olefin-based polymer more preferably contains, as a constituent, ethylene or α-olefin having a carbon number of <NUM> to <NUM>. Specific examples of the α-olefin include propylene, <NUM>-butene, <NUM>-methyl-<NUM>-pentene, <NUM>-hexene, <NUM>-octene, <NUM>-nonene, and <NUM>-decene. Further preferable examples of the olefin-based polymer include: homopolymers of ethylene, propylene, <NUM>-butene, <NUM>-methyl-<NUM>-pentene, <NUM>-hexene, and <NUM>-octene; and copolymers obtained by copolymerization of two or more types selected from ethylene, propylene, <NUM>-butene, <NUM>-methyl-<NUM>-pentene, <NUM>-hexene, and <NUM>-octene (e.g., an ethylene-propylene copolymer, a propylene-<NUM> butene copolymer, a terpolymer of ethylene-propylene-<NUM> butene, an ethylene-<NUM>-octene copolymer, and the like). One kind of these olefin-based polymers may be used alone, or two or more kinds of these olefin-based polymers may be used in combination.

As the olefin-based polymer, a commercially available product may be used. Examples of commercially available olefin-based polymers include REXTAC (registered trademark) series manufactured by REXtac, LLC. (e.g., REXTAC (registered trademark) <NUM>, REXTAC (registered trademark) <NUM>, REXTAC (registered trademark) <NUM>, and REXTAC (registered trademark) <NUM>); VESTOPLAST (registered trademark) series manufactured by Evonik Industries AG (e.g., VESTOPLAST (registered trademark) <NUM>, VESTOPLAST (registered trademark) <NUM>, VESTOPLAST (registered trademark) <NUM>, VESTOPLAST (registered trademark) <NUM>, VESTOPLAST (registered trademark) <NUM>, and VESTOPLAST (registered trademark) <NUM>); Eastflex (registered trademark) series manufactured by Eastman Chemical Company (e.g., Eastflex (registered trademark) P1010); L-MODU (registered trademark) series manufactured by Idemitsu Kosan Co. (e.g., L-MODU (registered trademark) S400, L-MODU (registered trademark) S600, and L-MODU (registered trademark) S901); Licocene (registered trademark) series manufactured by Clariant AG (e.g., Licocene (registered trademark) PP1602, Licocene (registered trademark) PP2602, Licocene (registered trademark) PP3602, and the like); AFFINITY (registered trademark) series manufactured by Dow Chemical Company (e.g., AFFINITY (registered trademark) GA1900, and AFFINITY (registered trademark) GA1950); and the like. One kind of these can be used alone, or two or more kinds of these can be used in combination. It is possible to use a combination of a commercially available olefin-based polymer and another olefin-based polymer.

The adhesive composition in accordance with an embodiment of the present invention contains the olefin-based polymer in an amount of preferably not less than <NUM>% by weight, more preferably not less than <NUM>% by weight, and further preferably not less than <NUM>% by weight. In a case where the adhesive composition contains the olefin-based polymer in an amount of not less than <NUM>% by weight, it is possible to provide an adhesive composition having more excellent self-adhesiveness. An upper limit of an amount of the olefin-based polymer contained in the adhesive composition in accordance with an embodiment of the present invention can be <NUM>% by weight, but is more preferably not more than <NUM>% by weight, and further preferably not more than <NUM>% by weight.

The olefin-based polymer used in the adhesive composition in accordance with an embodiment of the present invention preferably has a storage modulus (G') at <NUM> of not more than <NUM>×<NUM><NUM> Pa. In a case where the storage modulus (G') at <NUM> of the olefin-based polymer is not more than <NUM>×<NUM><NUM> Pa, it is advantageously possible to provide an adhesive composition having excellent self-adhesiveness. The storage modulus (G') at <NUM> of the olefin-based polymer is not particularly limited, and may be not less than <NUM>.

Here, in a case where the adhesive composition in accordance with an embodiment of the present invention contains two or more types of olefin-based polymers, a storage modulus (G') at <NUM> of a mixture of the two or more types of olefin-based polymers is regarded as the storage modulus (G') at <NUM> of the olefin-based polymer in the adhesive composition. A storage modulus (G') is a value measured in the manner described in Examples.

A weight-average molecular weight of the olefin-based polymer is more than <NUM>,<NUM>. In a case where the weight-average molecular weight of the olefin-based polymer is more than <NUM>,<NUM>, it is unlikely that a breakage will occur when an adhesive composition containing the olefin-based polymer is used to form an adhesive layer. Therefore, such an olefin-based polymer can be suitably used as a base polymer of an adhesive composition. The weight-average molecular weight of the olefin-based polymer is more preferably not less than <NUM>,<NUM>, and further preferably not less than <NUM>,<NUM>. An upper limit of weight-average molecular weight of the olefin-based polymer is not particularly limited, and may be, for example, not more than <NUM>,<NUM>.

The term "weight-average molecular weight" herein refers to a value obtained by gel permeation chromatography (GPC) on a polystyrene basis.

In an embodiment of the present invention, it is preferable that the olefin-based polymer has melt viscosity at <NUM> of <NUM> mPa·s to <NUM>,<NUM> mPa·s. In a case where the olefin-based polymer has melt viscosity at <NUM> of not less than <NUM> mPa·s, it is easy to control fluidity, and such an olefin-based polymer can be suitably used as a base polymer of an adhesive composition. In a case where the olefin-based polymer has melt viscosity at <NUM> of not more than <NUM>,<NUM> mPa·s, melt viscosity of the adhesive composition is not excessively high, and therefore coating with the adhesive composition can be easily carried out. The melt viscosity at <NUM> of the olefin-based polymer is more preferably <NUM>,<NUM> mPa·s to <NUM>,<NUM> mPa·s, and further preferably <NUM>,<NUM> mPa·s to <NUM>,<NUM> mPa·s. Herein, the term "melt viscosity" refers to a value measured in the manner described in Examples.

In the adhesive composition in accordance with an embodiment of the present invention, no inorganic particles are blended. As early described, in the conventional hot melt-type self-adhesive agent, an inorganic filler is blended in order to provide an adhesive composition having large self-adhesive force and low tack on the adhesive surface. In the adhesive composition in accordance with an embodiment of the present invention, no inorganic particles, such as an inorganic filler, are blended. Examples of the inorganic particles that are not blended in the adhesive composition include calcium carbonate, zinc oxide, silica, aluminum silicate, talc, diatomaceous earth, silica sand, pumice powder, slate powder, mica powder, asbestos, aluminum sol, alumina white, aluminum sulfate, barium sulfate, lithopone, calcium sulfate, molybdenum disulfide, graphite, glass fiber, glass sphere, monocrystalline potassium titanate, carbon fiber, active zinc oxide, zinc carbonate, magnesium oxide, basic magnesium carbonate, litharge, red lead, white lead, calcium hydroxide, activated calcium hydroxide, titanium oxide, and the like. Therefore, there is no separation (aggregation) or precipitation of the constituents of the adhesive composition in accordance with an embodiment of the present invention. Therefore, it is possible to provide an adhesive composition having excellent productivity.

The adhesive composition in accordance with an embodiment of the present invention may contain a wax. In a case where the adhesive composition in accordance with an embodiment of the present invention contains a wax, it is possible to bring about an advantage of providing an adhesive composition with reduced stickiness (tack).

Examples of the wax include: animal-based wax, such as shellac wax and beeswax; plant-based wax such as carnauba wax and sumac wax; polyolefin-based wax such as polyethylene wax, polypropylene wax, and ethylene-vinyl acetate copolymer-based wax; mineral-based wax such as paraffin wax and macrocrystalline wax; synthetic wax such as Fischer-Tropsch wax; and the like. Among these, the wax is more preferably an aliphatic hydrocarbon-based wax. In a case where the wax is an aliphatic hydrocarbon-based wax, it is possible to bring about an advantage of providing an adhesive composition with further reduced tack. Examples of the aliphatic hydrocarbon-based wax include polyolefin-based wax, paraffin wax, macrocrystalline wax, Fischer-Tropsch wax, and the like.

The adhesive composition in accordance with an embodiment of the present invention contains the wax preferably in an amount of <NUM>% by weight to <NUM>% by weight, more preferably in an amount of <NUM>% by weight to <NUM>% by weight, further preferably in an amount of <NUM>% by weight to <NUM>% by weight, and particularly preferably in an amount of <NUM>% by weight to <NUM>% by weight. In a case where the amount of the wax contained in the adhesive composition is not more than <NUM>% by weight, it is possible to bring about an advantage that self-adhesiveness of the adhesive composition is not likely to be insufficient. In a case where the amount of the wax contained in the adhesive composition is not less than <NUM>% by weight, it is possible to bring about an advantage of adjusting tack of the adhesive composition to an intended range.

In a case where the adhesive composition in accordance with an embodiment of the present invention contains a tackifier resin, the adhesive composition particularly preferably contains the wax in an amount of not less than <NUM>% by weight, from the viewpoint of adjustment of tack.

A weight-average molecular weight of the wax is between <NUM> and <NUM>,<NUM>. In a case where the weight-average molecular weight of the wax is not less than <NUM>, it is easy to control fluidity, and such a wax can be suitably used as a wax. In a case where the weight-average molecular weight of the wax is not more than <NUM>,<NUM>, viscosity of the adhesive composition is not likely to become excessively high, and therefore the adhesive composition can be easily coated. The weight-average molecular weight of the wax is more preferably <NUM>,<NUM> to <NUM>,<NUM>, further preferably <NUM>,<NUM> to <NUM>,<NUM>.

The wax has a transition temperature of preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, and further preferably <NUM> to <NUM>. In a case where the transition temperature of the wax is not less than <NUM>, stickiness is not likely to occur even in a high-temperature environment. In a case where the transition temperature of the wax is not more than <NUM>, a melting temperature of the adhesive composition does not become excessively high, and therefore the adhesive composition is not likely to be deteriorated by heat.

The wax has a transition heat of preferably <NUM> J/g to <NUM> J/g, more preferably <NUM> J/g to <NUM> J/g. In a case where the transition heat of the wax is not less than <NUM> J/g, cohesive force of the adhesive composition is not reduced, and therefore blocking is not likely to occur when the adhesive composition is stuck to another material. In a case where the transition heat of the wax is not more than <NUM> J/g, it is not likely that adhesive force is reduced when the adhesive compositions are stuck together.

Examples of the polyolefin-based wax include homopolymers of any of olefin monomers such as ethylene, propylene, butylene, and pentene, and copolymers obtained by copolymerization of two or more types of these olefin monomers. Specifically, the polyolefin-based wax may be low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene, polybutene, or the like. Examples of commercially available products of the polyolefin-based wax include Biscol <NUM>-P, Biscol <NUM>-P, Biscol <NUM>-P, and Biscol <NUM>-P (manufactured by Sanyo Chemical Industrial Co. ); Hi-WAX NP055, Hi-WAX NP105, Hi-WAX NP505, and Hi-WAX NP805 (manufactured by Mitsui Chemicals, Inc. ); Licowax PP230, Licowax PE130, and Licowax PE520 (manufactured by Clariant AG); and the like.

Examples of commercially available products of the paraffin wax include Paraffin WAX-<NUM> (manufactured by NIPPON SEIRO CO. ), and the like.

Examples of commercially available products of the microcrystalline wax include WAXREX2480 (manufactured by Exxon Mobile Inc. ); UNILIN series (manufactured by Toyo ADL Corporation); Hi-Mic series (manufactured by NIPPON SEIRO CO. ); and the like.

Examples of commercially available products of the Fischer-Tropsch wax include SX105 (manufactured by NIPPON SEIRO CO. ), and the like.

As the wax, one kind of these can be used alone, or two or more kinds of these can be used in combination.

The adhesive composition in accordance with an embodiment of the present invention may include a tackifier resin. In a case where the adhesive composition in accordance with an embodiment of the present invention contains a tackifier resin, it is possible to bring about an advantage of providing an adhesive composition having excellent adhesiveness (self-adhesiveness).

The adhesive composition in accordance with an embodiment of the present invention contains the tackifier resin in an amount of preferably <NUM>% by weight to <NUM>% by weight, more preferably in an amount of <NUM>% by weight to <NUM>% by weight, more preferably in an amount of <NUM>% by weight to <NUM>% by weight, and further preferably in an amount of <NUM>% by weight to <NUM>% by weight. In a case where the amount of the tackifier resin contained in the adhesive composition is not more than <NUM>% by weight, it is possible to bring about an advantage that tack of the adhesive composition is not likely to be excessive. In a case where the amount of the tackifier resin contained in the adhesive composition is not less than <NUM>% by weight, it is possible to bring about an advantage of adjusting adhesiveness of the adhesive composition to an intended range.

In an embodiment of the present invention, the tackifier resin may be a natural resin, a petroleum-based resin, or a combination thereof. Examples of the tackifier resin include rosin acid, rosin ester, a hydrocarbon resin, a synthetic polyterpene resin, a natural terpene resin, hydrogen additives of these, combinations of a plurality of resins, and the like.

Specific examples of the tackifier resin include: derivatives of rosins and modified rosins including rosin alcohol, methyl esters of rosin, diethylene glycol esters of rosin, glycerol esters of rosin, and partially hydrogenated rosins, completely hydrogenated rosins, or polymerized rosins thereof, and pentaerythritol esters and partially hydrogenated rosins, completely hydrogenated rosins, or polymerized rosins thereof; natural resins commercially available under the trade names such as gum rosin, wood rosin, and tall oil rosin; modified rosins such as polymerized rosins and partially hydrogenated rosins; polyterpene-based resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers; terpene modified products such as a terpene-phenol copolymer and an α-pinene-phenol copolymer; aliphatic petroleum resins; alicyclic petroleum resins; cyclopentadiene resins; aromatic petroleum resins; phenol-based resins; alkylphenol-acetylene-based resins; styrene-based resins; xylene-based resins; coumarone-indene resins; a copolymer of vinyl toluene and α-methyl styrene; and the like. One kind of these can be used alone, or two or more kinds of these can be used in combination.

As the tackifier resin, a commercially available product may be used. Examples of commercially available tackifier resins include I-MARV (registered trademark) P-<NUM> manufactured by Idemitsu Kosan Co. , Sylvalite (registered trademark) RE-<NUM> manufactured by Kraton, ARKON (registered trademark) P-<NUM> manufactured by Arakawa Chemical Industries, Ltd. , and the like. One kind of these can be used alone, or two or more kinds of these can be used in combination. It is possible to use a combination of a commercially available tackifier resin and another tackifier resin.

The adhesive composition in accordance with an embodiment of the present invention may further contain, if necessary, an additive other than the above described components, provided that the effect of the present invention is not impaired. Examples of such additives include stabilizers, fluorescent agents, antioxidants, ultraviolet absorbers, colorants, and the like.

An amount of the other additives contained in the adhesive composition is not limited as long as the effect of the present invention is not impaired, and may be, for example, not more than <NUM>% by weight.

The adhesive composition in accordance with an embodiment of the present invention may contain a component which is in a liquid form at normal temperature, if necessary. However, the absence of a liquid component (such as an oil or a liquid resin) eliminates a risk that the liquid component of the adhesive composition seeps through a substrate.

The adhesive composition in accordance with an embodiment of the present invention can be produced by heating and kneading an olefin-based polymer and, optionally, a wax and a tackifier resin at <NUM> to <NUM>, preferably at <NUM>. A method of heating and kneading is not particularly limited, and may be a method using, for example, a kneader-ruder, an extruder, a Banbury mixer, a roller, or the like. In a case where the temperature at kneading is not less than <NUM>, crystals contained in the olefin-based polymer melt and disperse uniformly, and stable performance can be exhibited. In a case where the temperature at kneading is not more than <NUM>, it is not likely that the olefin-based polymer will be deteriorated by heat.

The adhesive composition in accordance with an embodiment of the present invention has a storage modulus (G') at <NUM> of <NUM> to <NUM>×<NUM><NUM> Pa, more preferably <NUM>×<NUM><NUM> to <NUM>×<NUM><NUM> Pa, further preferably <NUM>×<NUM><NUM> to <NUM>×<NUM><NUM> Pa, and particularly preferably <NUM>×<NUM><NUM> to <NUM>×<NUM><NUM> Pa. According to the configuration, it is possible to provide an adhesive composition having excellent self-adhesiveness.

The adhesive composition in accordance with an embodiment of the present invention has a storage modulus (G') at <NUM> of <NUM>×<NUM><NUM> Pa to <NUM>×<NUM><NUM> Pa, preferably <NUM>×<NUM><NUM> Pa to <NUM>×<NUM><NUM> Pa, more preferably <NUM>×<NUM><NUM> Pa to <NUM>×<NUM><NUM> Pa, and further preferably <NUM>×<NUM><NUM> Pa to <NUM>×<NUM><NUM> Pa. According to the configuration, it is possible to provide an adhesive composition that is not likely to break a substrate (e.g., paper) when peeling off the adhesive composition.

The adhesive composition in accordance with an embodiment of the present invention has peel strength (hereinafter, referred to also as self-adhesive force) at <NUM> of preferably not less than <NUM> N/cm, more preferably not less than <NUM> N/cm, further preferably not less than <NUM> N/cm, after the adhesive compositions are adhered to each other and left to stand still at <NUM> for <NUM> hours. In a case where the self-adhesive force is not less than <NUM> N/cm, it is possible to provide an adhesive composition having excellent self-adhesiveness. Self-adhesive force is a value measured in the manner described in Examples.

The adhesive composition in accordance with an embodiment of the present invention has peel strength from fine paper (hereafter simply referred to also as peel strength) at <NUM> of preferably not more than <NUM> N/cm, more preferably not more than <NUM> N/cm, further preferably not more than <NUM> N/cm, after the adhesive composition is adhered to fine paper, pressurized at <NUM> kPa at <NUM>, and left to stand still for <NUM> hours. In a case where the peel strength of the adhesive composition is not more than <NUM> N/cm, the adhesive composition can be easily peeled off without breaking a substrate (e.g., paper). In other words, it is possible to bring about an advantage of excellent anti-blocking property.

The adhesive composition in accordance with an embodiment of the present invention preferably does not contain a solvent. In a case where the adhesive composition in accordance with an embodiment of the present invention does not contain a solvent, it is not necessary to evaporate the solvent after application of the adhesive composition. Therefore, it is possible to increase productivity, and it does not require large-scale equipment such as a drying oven. In addition, a residual solvent does not come into question. Therefore, the adhesive composition can be suitably used as a self-adhesive agent for food. Herein, the phrase "not contain a solvent" means that an amount of a solvent contained in the adhesive composition is not more than <NUM>% by weight.

The amount of a solvent contained in the adhesive composition (also referred to as a residual solvent amount) is more preferably not more than <NUM>% by weight, and particularly preferably <NUM>. The amount of a solvent contained in the adhesive composition can be obtained, for example, by gas chromatography.

The adhesive composition in accordance with an embodiment of the present invention which is configured as described above has excellent self-adhesiveness and anti-blocking property.

Therefore, the adhesive composition can be suitably used as a self-adhesive agent in particular.

The present invention is not limited to the foregoing embodiment, but can be altered variously by a skilled person in the art within the scope of the claims. The present invention also encompasses, in its technical scope, any embodiment derived by appropriately combining technical means disclosed in differing embodiments.

The following description will more specifically discuss the present invention with reference to Examples. Note, however, that the present invention is not limited to those Examples.

As the olefin-based polymer, the following polymers were used.

Quintac (registered trademark) 3433N [styrene-isoprene block copolymer] manufactured by Zeon Corporation.

DINA [diisononyl adipate] manufactured by DAIHACHI CHEMICAL INDUSTRY CO.

CARBITAL (registered trademark) S [calcium carbonate] manufactured by IMERYS Minerals Japan.

(Storage moduli of olefin-based polymer and adhesive composition).

A storage modulus of the olefin-based polymer or the adhesive composition was measured with use of a dynamic viscoelasticity measurement device (manufactured by TA Instruments Japan Inc. : rheometer ARES-RDA). The following (<NUM>) through (<NUM>) indicate measurement procedures.

A sample for measuring self-adhesiveness and anti-blocking property was prepared by applying, to fine paper (OKH-<NUM>, manufactured by Oji Paper Co. ) as a substrate, the adhesive composition by a thickness of <NUM> with use of a slot coater (manufactured by SUNTOOL CORPORATION).

The self-adhesiveness of the adhesive composition was measured and evaluated according to the following procedures (<NUM>) through (<NUM>). (<NUM>) The sample prepared in <Preparation of sam-ple> was cut out in a size of <NUM> × <NUM>, and a surface (paper surface) opposite to a surface to which the adhesive composition was applied was stuck to a PP resin plate.

Excellent: The peel strength is not less than <NUM> N/cm and the fine paper which is the substrate is broken.

Good: The peel strength is not less than <NUM> N/cm or the fine paper which is the substrate is broken.

Poor: The peel strength is less than <NUM> N/cm and the fine paper which is the substrate is not broken.

The anti-blocking property of the adhesive composition was measured and evaluated according to the following procedures (<NUM>) through (<NUM>).

Good: The peel strength is less than <NUM> N/cm and the sample was peeled off at the interface between the fine paper and the adhesive surface.

Poor: The peel strength is not less than <NUM> N/cm or the fine paper which is the substrate is broken.

The adhesive composition (<NUM>) was put into a glass vial (manufactured by ISOYA GLASS INDUSTRY CO. , M140), and was left to stand still at <NUM> for <NUM> hours. After the leaving to stand still, separation and precipitation of the components were checked by visual inspection.

Good: Separation and precipitation were not visually confirmed.

Poor: Separation or precipitation was visually confirmed.

The melt viscosity of the olefin-based polymer was measured using a method described in JIS K6862 at a described temperature with use of a Brookfield-type viscometer (H3 rotor).

The transition temperature and transition heat of the wax were measured using a differential scanning calorimeter (DSC) with a method described in JIS K <NUM>. Specifically, the transition temperature and transition heat of the wax were measured according to the following procedures (<NUM>) through (<NUM>).

An olefin-based polymer (REXTAC (registered trademark) RT2304) (<NUM>% by weight), an aliphatic hydrocarbon-based wax (Biscol (registered trademark) 330P) (<NUM>% by weight), and a tackifier resin (I-MARV (registered trademark) P-<NUM>) (<NUM>% by weight) were kneaded in a heating kneader (SV1-1GH-E type kneader, manufactured by MORIYAMA) at <NUM>, and thus an adhesive composition (<NUM>% by weight) was prepared.

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the olefin-based polymer was changed to VESTOPLAST (registered trademark) <NUM> (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the olefin-based polymer was changed to REXTAC (registered trademark) RT2880 (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the olefin-based polymer was changed to a mixture of VESTOPLAST (registered trademark) <NUM> (<NUM>% by weight) and VESTOPLAST (registered trademark) <NUM> (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the aliphatic hydrocarbon-based wax was changed to WAXREX (registered trademark) <NUM> (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the aliphatic hydrocarbon-based wax was changed to SX-<NUM> (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the aliphatic hydrocarbon-based wax was changed to Licowax (registered trademark) PP230 (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the tackifier resin was changed to Sylvalite (registered trademark) RE-<NUM> (<NUM>% by weight).

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the olefin-based polymer was changed to VESTOPLAST (registered trademark) <NUM> (<NUM>% by weight), the amount of the aliphatic hydrocarbon-based wax (Biscol (registered trademark) 330P) was changed to <NUM>% by weight, and the amount of the tackifier resin (I-MARV (registered trademark) P-<NUM>) was changed to <NUM>% by weight.

For the resulting adhesive compositions of Examples <NUM> through <NUM>, a storage modulus at <NUM>, a storage modulus at <NUM>, self-adhesiveness, anti-blocking property, and presence or absence of separation and precipitation were measured and evaluated. Results are shown in Table <NUM>. Numerical values of each component in Table <NUM> each indicate a percentage by weight of each component in the adhesive composition.

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the amount of the tackifier resin (I-MARV (registered trademark) P-<NUM>) was changed to <NUM>% by weight and no wax was added.

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that the amount of the aliphatic hydrocarbon-based wax (Biscol (registered trademark) 330P) was changed to <NUM>% by weight, and no tackifier resin was added.

An adhesive composition was prepared in a manner similar to that of Example <NUM>, except that an inorganic filler (CARBITAL (registered trademark) S) (<NUM>% by weight), which was inorganic particles, was added and no wax was added.

In a heating kneader (SV1-1GH-E type kneader, manufactured by MORIYAMA), Quintone (registered trademark) S-<NUM>, which is a tackifier resin (<NUM>% by weight), styrene-based elastomer Quintac (registered trademark) 3433N (<NUM>% by weight), Sylvares (registered trademark) HP2040HM (<NUM> weight%), and DINA (<NUM>% by weight), and CARBITAL (registered trademark) S (<NUM>% by weight), which is an inorganic filler, were kneaded at <NUM>, and thus an adhesive composition (<NUM>% by weight) was prepared.

For the resulting adhesive compositions of Comparative Examples <NUM> through <NUM>, a storage modulus at <NUM>, a storage modulus at <NUM>, self-adhesiveness, anti-blocking property, and presence or absence of separation and precipitation were measured and evaluated. Results are shown in Table <NUM>. Numerical values of each component in Table <NUM> each indicate a percentage by weight of each component in the adhesive composition.

As is clear from the comparison between Tables <NUM> and <NUM>, a comparison of Examples <NUM> through <NUM> with Comparative Examples <NUM>, <NUM>, and <NUM> showed that, in the cases where the storage modulus at <NUM> of the adhesive composition was more than <NUM>×<NUM><NUM> Pa, the self-adhesiveness of the resulting adhesive composition was poor. Moreover, a comparison of Examples <NUM> through <NUM> with Comparative Examples <NUM> and <NUM> showed that, in the cases where the storage modulus at <NUM> of the adhesive composition was less than <NUM>×<NUM><NUM> Pa, the anti-blocking property of the resulting adhesive composition was poor. Further, a comparison of Examples <NUM> through <NUM> with Comparative Examples <NUM> and <NUM> showed that, in the case where inorganic particles were blended in the adhesive composition, separation or precipitation occurred, resulting in poor productivity.

These results indicated that the adhesive compositions which had the storage modulus at <NUM> and the storage modulus at <NUM> falling within the predetermined ranges and in which no inorganic particles were blended exhibit excellent self-adhesiveness and anti-blocking property, and can be efficiently produced.

Claim 1:
An adhesive composition comprising an olefin-based polymer, having a weight-average molecular weight of more than <NUM>,<NUM>, and a wax, having a weight-average molecular weight between <NUM> and <NUM>,<NUM>, weight-average molecular weight being obtained by gel permeation chromatography on polystyrene basis,
- in said adhesive composition, no inorganic particles being blended,
- said adhesive composition having a storage modulus, measured using a dynamic viscoelasticity measurement device as described in the description, at <NUM> of <NUM> to <NUM>×<NUM><NUM> Pa, and a storage modulus at <NUM> of <NUM>×<NUM><NUM> Pa to <NUM>×<NUM><NUM> Pa, and
- the wax having a transition temperature, measured using a differential scanning calorimeter as described in the description, of <NUM> to <NUM>.