JP5532700B2 - Alkali-dispersed hot-melt pressure-sensitive adhesive composition, method for producing the same, and container using the same - Google Patents

Description

  The present invention relates to an alkali-dispersed hot-melt pressure-sensitive adhesive composition, and in particular, containers such as glass bottles and PET (polyethylene terephthalate) bottles used for soft drinks, seasonings, detergents, shampoos, edible oils, cosmetics, pharmaceuticals, and the like. The present invention relates to a pressure-sensitive adhesive composition suitable as a label pressure-sensitive adhesive. The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention is used in the same manner as the conventional one when used, but it can be peeled off without leaving any adhesive and can be easily removed with a hot alkaline aqueous solution after use. Since the label is peeled off from a container such as a PET bottle without any adhesive residue, it is particularly suitable for recycling of a container such as a PET bottle. Furthermore, the present invention relates to a method for producing the alkali-dispersed hot melt pressure-sensitive adhesive composition, a container having a label adhered thereto using the alkali-dispersed hot-melt pressure-sensitive adhesive composition, and a method for producing the same.

  In recent years, the amount of PET bottles used for beverages has increased along with the amount of PET bottles produced. The used PET bottles are discharged as garbage, but a recycling system has been established by the Recycled Resource Utilization Promotion Law so that the amount of the garbage is not increased as much as possible and can be recycled as resources. In recycling of PET bottles, the PET bottles collected after use are cut into 8 mm square pellets, soaked in hot alkali (1.5% NaOH at 85 to 90 ° C.) for about 15 minutes to remove the label, washed with water, Labels are removed by drying and wind sorting, and PET pellets are recycled.

  Conventionally, a label is adhered to a bottle or the like with a pressure-sensitive adhesive with such a strength that it cannot be peeled off by hand. In PET bottles, body-wound labels are often used as labels, and hot melt pressure-sensitive adhesives are generally used as pressure-sensitive adhesives. However, when a conventional hot melt pressure-sensitive adhesive is used, the label does not peel off even if it is immersed in warm water or an aqueous alkaline solution, which has been an obstacle to recycling of the PET bottle.

  For this reason, the label of the PET bottle is replaced with a stretch label, a shrink label, or the like from the one using the hot melt pressure-sensitive adhesive, which makes it possible to recycle the PET bottle. A stretch label uses the principle of a rubber band that returns to its original state when stretched and released. The stretched label is stretched over a plastic bottle and released to return the label to its original position and then wrap it around. On the other hand, a shrink label covers a PET bottle and is shrunk by the heat of a heater or steam, thereby closely attaching the film to the container. However, stretch labels and shrink labels are expensive.

  As an adhesive soluble in an alkaline aqueous solution, there is an aqueous emulsion type adhesive. However, the aqueous emulsion type adhesive has a problem that the working place becomes dirty at the time of labeling, and there are problems in handling properties such as a change in solid content concentration during the work. The method of adhering the body-wound label using the hot melt adhesive is less costly than the stretch label or shrink label, etc., so that the hot melt adhesive soluble in hot water or aqueous alkaline solution suitable for recycling PET bottles The development of Furthermore, when using a body-wound label using a hot-melt adhesive, the energy consumption and carbon dioxide generation during labeling are both about 1/10 compared to the case of shrink labels, which is very difficult for the environment. friendly. A composition containing a polyester copolymer has been proposed as a hot-melt pressure-sensitive adhesive composition that dissolves or disperses in such hot water or a hot alkaline aqueous solution (see, for example, Patent Document 1). However, since polyester has poor heat resistance, it has a problem that the adhesive strength is not stable due to partial thermal decomposition. There is also a problem such as odor.

  In order to recycle PET bottles, the PET Bottle Recycling Promotion Council, together with related organizations and ministries, will proceed with the development of various laws and guidelines regarding PET bottles. Created self-design guidelines for PET bottles and is conducting self-regulation. In this voluntary regulation, either a stretch label or shrink label, or a film or paper label such as an OPP (stretched polypropylene) film, PE (polyethylene) film, or PET film, and either hot water peeling or hot alkali peeling The label had to be peeled off.

  The method for peeling the label from the PET bottle is based on the “designated PET bottle self-regulation guidelines” issued by the PET Bottle Recycling Promotion Council. That is, in the hot alkali peeling test, a pellet made by cutting a bottle with a label, printing, etc., was immersed in a 1.5% NaOH aqueous solution at 90 ° C. at a pellet concentration of 10% (weight ratio) and slowly slowed for 15 minutes. Stir. Subsequently, it filters with a filter and visually observes a pellet. When the label peels off and printing ink, adhesive, etc. do not remain in the bottle, it is judged that there is a hot alkali peelability.

  The applicants previously filed a patent application for an alkali-dispersed hot-melt pressure-sensitive adhesive composition that meets such criteria (see Patent Document 2). This alkali-dispersed hot-melt pressure-sensitive adhesive composition includes a thermoplastic elastomer (A), a solid tackifier (B) having an acid value of 100 mgKOH / g to 300 mgKOH / g, a wax (C), and a carbon number of 6 or more. It contains glyceride (D) of 18 or less fatty acid. Labels attached to PET bottles using this pressure-sensitive adhesive composition can be peeled off manually, and the label can be peeled off with hot alkaline aqueous solution without any adhesive residue. Since the label does not reattach, it meets the criteria of the above guidelines. However, when the label is manually peeled off, the hot melt adhesive remains in the PET bottle, and depending on the recycler, the PET bottle from which the label has been manually peeled off becomes a recycling compatible product. Will be mixed. For this reason, according to the recycling standard of the PET recycling promotion council, those that cause adhesive residue due to manual peeling are ranked C. In the PET recycling promotion council, the C-rank is working to make it higher than the B-rank (has a hot alkali peelability and can be peeled off without adhesive residue), so the alkali-dispersed hot-melt adhesive applied earlier However, there is a problem that the current adhesive for labeling PET bottles is not easily spread.

Japanese National Patent Publication No. 11-512134 JP 2005-220244 A

  An object of the present invention is to provide an alkali-dispersed hot-melt pressure-sensitive adhesive composition that can peel off an adhesive such as a label without leaving adhesive residue, and can easily remove the adhesive from a substrate with a hot alkaline aqueous solution without adhesive residue. Is to provide.

  In addition, another object of the present invention is provided by labels such as paper, OPP film, PE (polyethylene) film, PET film, and the like, especially PET bottle recycling promotion council attached to substrates such as glass bottles and plastic containers. Hot melt pressure-sensitive adhesive composition suitable for “self-design guidelines for type 2 designated PET bottles” and suitable as adhesive for PET bottle paper and OPP film such as soft drinks and soy sauce. When cooling, etc., the label will not peel even if it is put in water, but if it is made into a pellet after collection and immersed in a hot alkaline aqueous solution, the label can be easily peeled off from the PET bottle without any adhesive residue and attached to the PET pellet again. Of the PET recycling promotion council by providing non-alkali-dispersed hot-melt adhesive compositions It is to enable the product of a PET bottle of A rank of regulation.

  Furthermore, in addition to the above characteristics, another object of the present invention is that the label can be attached with a predetermined strength, the temperature dependence of the adhesive strength is low, and it does not peel off during normal use, but peels off. When the need arises, an alkali-dispersed hot-melt pressure-sensitive adhesive composition that can be peeled off by hand peeling without any adhesive residue is provided.

  Another object of the present invention is to provide a method for producing an alkali-dispersed hot melt pressure-sensitive adhesive composition having the above characteristics.

  Another object of the present invention is to provide a container in which a body-wound label is bonded using an alkali-dispersed hot-melt pressure-sensitive adhesive composition having the above characteristics.

  Moreover, the other object of this invention is to provide the manufacturing method of the container which adhere | attached the wound label using the alkali dispersion-type hot-melt adhesive composition which has the said characteristic.

The present invention relates to the following alkali-dispersed hot-melt pressure-sensitive adhesive composition and method for producing the same, and a container and method for producing the same.
[1] Thermoplastic elastomer (A), rosin tackifier (B) having an acid value of 100 mgKOH / g or more and 300 mgKOH / g or less, synthetic oil (C), wax having a penetration of 25 ° C. of 10 dmm or less An alkali-dispersed hot-melt pressure-sensitive adhesive composition comprising (D) and polyethylene glycol (E) having a number average molecular weight of 1,000 or more.
[2] The alkali-dispersed hot-melt pressure-sensitive adhesive composition as described in [1] above, wherein the wax (D) is a paraffin wax having an oil content of 0.2% by weight or less.

  [3] The alkali-dispersed hot-melt pressure-sensitive adhesive composition as described in [1] above, wherein the wax (D) is a synthetic polyethylene wax.

  [4] The alkali-dispersed hot-melt pressure-sensitive adhesive composition according to any one of [1] to [3], wherein the melting point of the wax (D) is 60 ° C. or higher and 135 ° C. or lower.

  [5] Thermoplastic elastomer (A), rosin tackifier (B) having an acid value of 100 mgKOH / g or more and 300 mgKOH / g or less, synthetic oil (C), wax having a penetration of 25 ° C. of 10 dmm or less (D) and polyethyleneglycol (E) having a number average molecular weight of 1,000 or more are blended at a temperature of 90 ° C. or higher and 180 ° C. or lower.

  [6] A container having a label adhered thereto using the alkali-dispersed hot-melt pressure-sensitive adhesive composition according to any one of [1] to [4].

  [7] The container described in [6] above, wherein the label is a body-wound label.

  [8] The container according to item [6] or [7], which is made of polyethylene terephthalate.

  [9] The container according to any one of [6] to [8] above, wherein the label is made of a stretched polypropylene film.

  [10] A container having a label adhered thereto, wherein the alkali-dispersed hot-melt pressure-sensitive adhesive composition according to any one of [1] to [4] is applied to a label and attached to the container. Manufacturing method.

  [11] The production method of the above-mentioned [10], wherein the label-printed surface is coated with an alkali-dispersed hot melt pressure-sensitive adhesive composition.

  The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention does not peel off the attached label or the like in a normal use state, but when it is necessary to peel off, the substrate such as a container by hand The label can be peeled off from the container without any adhesive residue, and even if the label is attached to, for example, a glass bottle or PET bottle, the label can be easily peeled off from the container and so on when immersed in a hot alkaline aqueous solution. It does not reattach.

  In addition, the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention has a label peeling requirement with hot alkaline water in the “Voluntary Guidelines for Designated PET Bottles” issued by the PET Bottle Recycling Promotion Council, Since it satisfies the requirement that it can be peeled without remaining, it can be preferably used as a pressure-sensitive adhesive for adhering a label to a PET bottle.

  Hereinafter, the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention, a production method thereof, a container, and a production method thereof will be described in more detail.

First, as described above, the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention includes a thermoplastic elastomer (A), a rosin-based tackifier (B) having an acid value of 100 mgKOH / g to 300 mgKOH / g, It comprises synthetic oil (C), wax (D) having a penetration of 10 ° C. or less at 25 ° C., and polyethylene glycol (E) having a number average molecular weight of 1,000 or more.
The thermoplastic elastomer (A) serves as a base polymer of the alkali-dispersed hot melt pressure-sensitive adhesive of the present invention. The thermoplastic elastomer is a material that has the same properties as vulcanized rubber at room temperature and is elastic, and is a high-molecular material that can be used as it is at an elevated temperature, like an ordinary thermoplastic resin. Thermoplastic elastomers have both a rubber component (soft segment: soft phase) with elasticity in the molecule and a molecular constrained component (eight segment: hard phase) to prevent plastic deformation. It has an intermediate property. The thermoplastic elastomer is (a) styrene (styrene block polymer), (b) olefin, (c) urethane, (d) polyester, (e) polyamide, (d) 1,2-butadiene, (F) Vinyl chlorides are known, and any of them can be used as the thermoplastic elastomer (A) of the present invention. Among them, styrene is preferred. Styrenic thermoplastic elastomer generally has a polystyrene block and a rubber intermediate block, and the polystyrene part forms a physical crosslink (domain) to serve as a bridge point, and the intermediate rubber block gives rubber elasticity to the product. . The intermediate soft segment includes polybutadiene (B), polyisoprene (I), and polyolefin elastomer (ethylene propylene, EB). Depending on the arrangement of the hard segment with polystyrene (S), linear (linear type) And radial (radical type). Among the preferable styrenic elastomers described above, in the present invention, styrene-ethylene-butylene-styrene block polymer (SEBS), styrene-ethylene-propylene-styrene block polymer (SEPS), styrene-isoprene-styrene block polymer (SIS), Styrene-butylene-butadiene-styrene block polymer (SBBS) or the like is preferably used, and styrene-ethylene-butylene-styrene block polymer (SEBS) is more preferable.

  In the present invention, a rosin tackifier having an acid value of 100 mgKOH / g or more and 300 mgKOH / g or less, preferably 170 mgKOH / g or more and 250 mgKOH / g or less is used as the component (B). Rosin is an amber, amorphous natural resin obtained from pine, and can be divided into gum rosin, wood rosin and tall oil rosin depending on the production. The main component is a mixture of abietic acid having three ring structures, a conjugated double bond, and a carboxyl group and its isomer, and has a bulky structure rich in reactivity. Due to its high reactivity, thermal stability is poor, and rosin is generally hydrogenated to improve stability. As the rosin-based tackifier (B) having an acid value of 100 mgKOH / g or more and 300 mgKOH / g or less according to the present invention, raw rosin having the acid value (unmodified rosin), hydrogenated rosin, (meth) Acrylic acid modified rosin, hydrogenated (meth) acrylic acid modified rosin, maleic acid modified rosin, hydrogenated maleic acid modified rosin, fumaric acid modified rosin, hydrogenated fumaric acid modified rosin, etc., preferably hydrogenated rosin or (Hydrogenated) Acrylic acid-modified rosin and the like, more preferably those subjected to the above-mentioned acid modification and / or hydrogenation, and more preferably a hydrogenated rosin tackifier. When the acid value is less than 100 mgKOH / g, there is a problem that the alkali dispersibility is lost. On the other hand, when the acid value is more than 300 mgKOH / g, there is a problem that the viscosity of the hot melt composition is increased or the softening point is increased. .

The acid value is the number of mg of potassium hydroxide (KOH) required to neutralize 1 g of the sample. This is measured, for example, by the following method. First, a sample is weighed accurately, placed in a 250 ml flask, added with 50 ml of ethanol or an equal volume of ethanol and ether, heated to dissolve, and titrated with 0.1 N potassium hydroxide solution with frequent shaking (indicator: phenol). Phthalein). The end point of the titration is the point at which the pale red color of the liquid remains for 30 seconds. Next, a blank test is performed and corrected by the same method, and the acid value is obtained from the following equation.
Acid value = [consumption of 0.1N potassium hydroxide solution (ml) × 5.611] / [[sample amount (g)]

  The synthetic oil (C) used in the present invention is an oil generally used as a plasticizer such as rubber or thermoplastic elastomer, a process oil produced in so-called petroleum refining, and is a paraffinic process oil or naphthenic oil. It is roughly divided into process oil and aromatic process oil. Process oil is a mixture of aromatic rings, naphthene rings, and paraffin chains. Generally, the aromatic carbon in the total carbon is 30 wt% or more, and the aromatic oil is 35 to 45 wt% in the naphthenic ring carbon. Naphthenics and those with 50% by weight or more of paraffin chain carbon are classified as paraffinic. Paraffinic crude oil is separated into paraffinic oil and aromatic oil by distillation, hydrogenation reforming, solvent extraction, and solvent dewaxing. Naphthenic crude oil is also separated into naphthenic and aromatic oils by distillation and solvent extraction. In the present invention, the synthetic oil (C) is preferably a paraffinic oil. There are various commercial products under the trade names such as “Diana Fresia” and “Diana Process Oil” from Idemitsu Kosan Co., Ltd., and “Fukor New Flex” and “Fukor Flex” from Fuji Kosan Co., Ltd. Grades are commercially available. Synthetic oil (C) is used in the present invention so as not to lower the adhesive strength at low temperatures.

The wax (D) having a penetration of 10 dmm or less at 25 ° C. is polyethylene, polypropylene, Fischer-Tropsch wax, paraffin wax, or microcrystalline wax. Paraffin wax having an oil content of 0.2% by weight or less or synthetic polyethylene wax is preferable. The penetration at 25 ° C. is a measurement method for determining the hardness of petroleum wax. A penetration gauge is used to apply a load of 100 g to the lower needle at 25 ° C. and determine how many mm the sample penetrates in 5 seconds. It was expressed as a numerical value (dmm) 10 times the value (JIS K 2235-5.4). Paraffin wax is a kind of petroleum wax. Petroleum wax (paraffin wax (solid wax at normal temperature separated and refined from vacuum distillation oil), microcrystalline wax (vacuum distilled bottom or wax solid at normal temperature separated and purified from heavy spilled oil), petrolatum (vacuum reduced pressure) Semi-solid wax at room temperature separated and purified from the distillation bottom). Since the paraffin wax is separated from the vacuum distillation fraction, it is composed of hydrocarbons having a carbon number distribution of about 20 to 40 and a molecular weight of about 300 to 500. These can be confirmed by gas chromatography analysis. Usually, about 90% by weight is normal paraffin, so the crystals are large. Oil refers to 1 g of sample dissolved in 15 ml of methyl ethyl ketone, cooled to −32 ° C., the precipitated wax is filtered, the solvent in the filtrate is evaporated, and the mass of residual oil is measured. (JIS K 2235-5.6).
When the oil content of the paraffin wax is 0.2% by weight or less, it is preferable in that the hot melt pressure-sensitive adhesive composition does not remain on the PET bottle when the label is peeled off.
For example, paraffin wax having an oil content of 0.01% by weight to 0.2% by weight is also commercially available from Nippon Seiwa Co., Ltd. under the trade name of paraffin wax “HNP series”. The melting point is preferably 64 ° C or higher and 80 ° C or lower, more preferably 75 ° C or higher and 77 ° C or lower.

  The synthetic polyethylene wax is polyethylene having a viscosity average molecular weight of 100 or more and 5,000 or less and a viscosity of 150 ° C. (the viscosity is measured in accordance with JIS K 6862-1984 A method) of 500 mPa · s or less. There are three typical methods for synthesizing polyethylene. (1) High pressure method: The most representative is the ICI method, and other BASF, du Pont method, Union Carbide method, etc. (2) Medium pressure method: Philips method, Standard (Indiana) method, etc. (3) Low pressure method: For example, the Ziegler method. It is commercially available under the trade names of “POLYWAX” from Baker Petrolite, “Neowax” from Yashara Chemical Co., Ltd., and “AC polyethylene” from Allied Signal. The melting point is preferably 70 ° C. or higher and 100 ° C. or lower, and more preferably 85 ° C. or higher and 95 ° C. or lower.

The polyethylene glycol (E) having a number average molecular weight of 1,000 or more is obtained by ring-opening polymerization of ethylene oxide, has a hydroxyl group at the terminal, and may be linear or branched. The number average molecular weight is 1,000 or more, preferably 60,000 or less. Those of 3,000 or more and 20,000 or less are more preferable. If it is less than 1,000, the cohesive force becomes small and the hot melt pressure-sensitive adhesive composition remains in the PET bottle when the label is peeled off. On the other hand, if the number average molecular weight is more than 60,000, the compatibility becomes poor and a hot melt pressure-sensitive adhesive composition cannot be produced.
The number average molecular weight was measured by a high temperature Gel Permeation Chromatography (GPC) method. The measurement conditions were a temperature of 40 ° C., the solvent was THF (the column used was Polymer Laboratories PLgel 5 μm MIXD-D), and the standard polymer was used in a polystyrene conversion method.

In the present invention, the thermoplastic elastomer (A) is used for increasing the cohesive strength of the pressure-sensitive adhesive.
The rosin-based tackifier (B) is used to increase the adhesive strength with the substrate.
Synthetic oil (C) is used for viscosity adjustment and elimination of adhesive residue on PET bottles when hand-peeled.
Furthermore, the wax (D) having a penetration of 10 ° C. or less at 25 ° C. is used for viscosity adjustment and elimination of adhesive residue on a PET bottle or the like when manually peeled off. When a wax having a penetration of 10 ° C. or more at 25 ° C. is used, there is a problem that the hot melt pressure-sensitive adhesive composition remains glued to the PET bottle when peeled by hand.
Polyethylene glycol (E) is used for the purpose of increasing the cohesive force by hardening the hot melt. If not added, the hot melt adhesive composition may remain in the PET bottle when the label is peeled off from the PET bottle at high speed.

In the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention, coloring materials such as antioxidants and fluorescent color formers for preventing thermal degradation and thermal decomposition can be added as necessary.
The wax (D) having a penetration of 10 ° C. or less at 25 ° C. of the present invention is preferably a wax having a melting point of 60 ° C. or more and 135 ° C. or less. In order to balance the adhesiveness remaining on the PET bottle and the adhesive strength, it is preferably 70 ° C. or higher and 95 ° C. or lower, more preferably 85 ° C. or higher and 95 ° C. or lower. When the melting point is less than 60 ° C., the hot melt pressure-sensitive adhesive composition may remain on the PET bottle when peeled by hand, and when it exceeds 135 ° C., the adhesiveness may be lowered. In the present invention, the peak top temperature of the endothermic peak of the wax measured by DSC is defined as the melting point of the wax.
The DSC of the wax was measured by using Perkin Elmer Pyris 1 manufactured by Perkin Elmer, Inc. The measurement was initially held at 0 ° C. for 5 minutes, then heated to 170 ° C. at a speed of 10 ° C./min, then 170 ° C. For 1 minute, then cooled down to 0 ° C at a speed of 40 ° C / minute, held at 0 ° C for 1 minute, and then heated to 170 ° C at a speed of 10 ° C / minute again. Of melting point.

  The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention comprises a predetermined amount of thermoplastic elastomer (A), a rosin-based tackifier (B) having an acid value of 100 mgKOH / g to 300 mgKOH / g, synthetic oil (C ), A wax (D) having a penetration of 25 ° C. of 10 dmm or less and a polyethylene glycol (E) having a number average molecular weight of 1,000 or more are blended to form a uniform mixture. The blending temperature is preferably 90 ° C. or higher and 180 ° C. or lower, and is preferably melted and blended. If the temperature is less than 90 ° C., there is a problem that blending is difficult to perform, while if it exceeds 180 ° C., problems such as browning due to thermal degradation and thermal decomposition occur. As an apparatus for blending, conventionally known and known blending apparatuses such as a stirrer and an extruder can be used. At this time, the order of melting, blending method, melting and blending may be arbitrary. For example, synthetic oil (C), polyethylene glycol (E) having a number average molecular weight of 1,000 or more, and penetration at 25 ° C. A wax (D) of 10 dmm or less is charged into a blender container, melted, and while continuing stirring, the thermoplastic elastomer (A) and the rosin-based tackifier (B) are sequentially added and blended to obtain a uniform mixture. It is formed by doing. Moreover, you may melt and stir these simultaneously with a twin-screw extruder.

  The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive for adhering paper, plastic films and the like to various substrates such as glass, plastic and metal. The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention can be peeled by hand as described above, and can easily peel off affixed paper, film, etc. with hot alkaline water. It is preferable to use as a pressure-sensitive adhesive for labels of glass containers such as glass bottles used in seasonings, detergents, shampoos, edible oils, cosmetics, pharmaceuticals, and plastic containers such as PET (polyethylene terephthalate) bottles. . However, the application of the pressure-sensitive adhesive of the present invention is not limited to this label application, and can be used as a pressure-sensitive adhesive for all conventionally known applications such as gum tape, clear case, and assembly. However, as specifically shown in the examples, the alkali-dispersed pressure-sensitive adhesive composition of the present invention has a label with a hot alkaline water in the “Voluntary Guidelines for Designated PET Bottles” issued by the PET Bottle Recycling Promotion Council. Since it satisfies the peeling requirement and the requirement that it can be peeled without adhesive residue at the time of manual peeling, the use as a pressure-sensitive adhesive when adhering a label to a PET bottle, that is, the recycling compatible pressure-sensitive adhesive for PET bottles is particularly preferable. .

  As described above, the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention is preferably used for bonding a PET bottle label. Usually, OPP, PE, PET, and paper are also used as the label base material for PET bottles. Further, as the label, the side opposite to the surface to which the alkali-dispersed hot melt pressure-sensitive adhesive composition is applied, that is, the surface of the label, or the surface to which the alkali-dispersed hot-melt pressure-sensitive adhesive composition is applied, that is, the back surface of the label Are appropriately printed. The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention can be applied to a printed label printing surface, and of course may be applied to an unprinted one. , Exhibit predetermined adhesiveness, peelability and hot alkaline water solubility. Further, the printing may be performed by printing the entire back surface of the label or printing a part of the surface. Printing may be performed by any conventionally known printing method such as gravure printing or UV printing.

  In PET bottles, in addition to those in which a label is attached to a part of the periphery of the PET bottle, a body-wrapped label that is wound so as to cover the periphery of the bottle is used. The agent composition is also preferably used for adhesion of the wound label. An OPP film is frequently used as such a body-wound label. The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention has good adhesion to the body-wrapped label such as the OPP film as well as the one printed on the back side and the one not printed. It can be carried out. The alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention may be applied to the entire label back surface, but the pressure-sensitive adhesive composition may be applied to a part of the label back surface. Examples of the application method include an open wheel method, a closed gun method, and a direct coating method. As a method in which no glue remains on the PET bottle or the like when peeled off, an open wheel method or a direct coating method is preferable.

  In order to attach a label to a PET bottle using the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention, for example, an alkali-dispersed material that is melted at a temperature of about 120 to 150 ° C. using an open wheel type device. The hot-melt pressure-sensitive adhesive composition is applied to the back of the label, and the label coated with the alkali-dispersed hot-melt pressure-sensitive adhesive composition is applied to a PET bottle.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

  In the following examples, the thermoplastic elastomer (A), the rosin-based tackifier (B) having an acid value of 100 mgKOH / g or more and 300 mgKOH / g or less, the synthetic oil (C), and the penetration at 25 ° C. The following were used as wax (D) which is 10 dmm or less, polyethylene glycol (E) having a number average molecular weight of 1,000 or more, and other materials.

○ Plastic elastomer (A)
Kraton G1650 (manufactured by Kraton Polymer Co., Ltd.) (hereinafter abbreviated as “G1650”)
Styrene-ethylene-butylene-styrene block polymer (SEBS)
Melt viscosity ^{* 1} ; 8,000 mPa · s
Clayton G1652 (manufactured by Clayton Polymer) (hereinafter abbreviated as “G1652”)
Styrene-ethylene-butylene-styrene block polymer (SEBS)
Melt viscosity ^{* 1} ; 1,350 mPa · s
Kraton G1726 (manufactured by Kraton Polymer Co., Ltd.) (hereinafter abbreviated as “G1726”)
Styrene-ethylene-butylene-styrene block polymer (SEBS)
Melt viscosity ^{* 1} : 200 mPa · s
The melt viscosity ^{* 1} is a melt viscosity at 25 ° C. of a toluene solution having a thermoplastic elastomer concentration of 25% by weight. The melt viscosity was measured using a B-type viscometer RB80L (manufactured by Toki Sangyo Co., Ltd.). 3 was carried out at a suitable rotational speed.
○ Liquid rubber / High Mall 4H (manufactured by Nippon Oil Corporation)
Polyisobutylene Viscosity average molecular weight: 40,000 (Viscosity average molecular weight: FCC method (FDA))

○ Rosin tackifier (B)
・ Licarodin F (Rika Finetech)
Acid value: 175 mgKOH / g
Softening point: 72 ° C
・ KE-604 (Arakawa Chemical Co., Ltd.)
Hydrogenated acrylic acid modified rosin Acid value: 240 mgKOH / g
Softening point: 125 ° C
○ Other tackifiers and YS Polystar (Yasuhara Chemical Co., Ltd.)
Terpene phenol resin (terpene phenol copolymer)
Acid value: 30 mg KOH / mg or less Softening point: 50 ° C. or less

○ Synthetic oil (C)
Diana process PW-90 (made by Idemitsu Kosan Co., Ltd.) (hereinafter abbreviated as “PW90”)
Paraffin-based process oil / Diana process PW-380 (manufactured by Idemitsu Kosan Co., Ltd.) (hereinafter abbreviated as “PW380”)
Paraffin-based process oil / process oil 100R (manufactured by Shell Chemical Co., Ltd.) (hereinafter abbreviated as “100R”).
Naphthenic process oil

○ Wax (D) having a penetration of 25 ° C of 10 dmm or less
HNP-9 (manufactured by Nippon Seiwa Co., Ltd.) (hereinafter abbreviated as “HMP-9”)
Needle penetration: 7dmm
Oil content: 0.1% by weight
Melting point: 76 ° C
Paraffin wax POLYWAX 655 (also referred to as “PW655”, manufactured by Baker Petrolite)
Needle penetration: 2dmm
Melting point: 90 ° C
Synthetic polyethylene wax ○ Wax having a penetration of more than 10 dmm at 25 ° C. and 140F paraffin wax (manufactured by Nippon Seiwa Co., Ltd.) (hereinafter abbreviated as “140F paraffin”)
Needle penetration: 11dmm
Oil content: 0.2% by weight
Melting point: 61 ° C
EAA wax ethylene-acrylic acid copolymer (manufactured by Allied Chemical Co.) (hereinafter “A-C5120”)
Needle penetration: 11.5dmm
Oil content: 0.25% by weight
Melting point: 65 ° C
Ethylene-acrylic acid copolymer (manufactured by Allied Chemical) (hereinafter “A-C5180”)
Needle penetration: 50dmm
Oil content: 0.22% by weight or more Melting point: 50 ° C. or less ○ Polyethylene glycol (E) having a number average molecular weight of 1,000 or more
Polyethylene glycol (manufactured by Sanyo Chemical)
Number average molecular weight 1,000 (hereinafter “PEG-1000”)
Number average molecular weight 2,000 (hereinafter “PEG-2000”)
Number average molecular weight 6,000 (hereinafter “PEG-6000”)
Number average molecular weight 20,000 (hereinafter “PEG-20000”)
○ Polyethylene glycol with a molecular weight of less than 1,000 Polyethylene glycol (manufactured by Sanyo Chemical Co., Ltd.)
Number average molecular weight 600 (hereinafter referred to as “PEG-600”)
○ Glyceride ・ Palm oil: Refined palm oil (manufactured by Tsukishima Food Industry Co., Ltd.)
(C6-C8)

Example 1
<Method for producing alkali-dispersed hot melt pressure-sensitive adhesive composition>
A stainless beaker equipped with a stirrer was charged with 32 parts by weight of synthetic oil (C): PW90, 7 parts by weight of wax (D): HNP-9 and 6 parts by weight of polyethylene glycol: PEG-1000, and heated. Melted. Heating was performed with care so that the contents would not be below 130 ° C and above 150 ° C. After melting, stirring is performed to obtain a uniform molten solution, and while maintaining the temperature below 150 ° C. and continuing stirring, 10 parts by weight of thermoplastic elastomer (A); G1650 is gradually added to the melt, and the addition is completed. Thereafter, 45 parts by weight of Licarodin F as a rosin-based tackifier (B) was added to form a molten homogeneous mixture, and cooled to prepare an alkali-dispersed hot-melt pressure-sensitive adhesive composition.

  The obtained alkali-dispersed hot-melt pressure-sensitive adhesive composition was evaluated for alkali peelability, adhesive residue, and adhesiveness (adhesive strength) (for OPP and PET) by the following methods. The alkali releasable hot-melt pressure-sensitive adhesive composition of Example 1 has both alkali peelability and adhesive residue, and adhesion (vs. OPP) is 1.5 N / 15 mm, and adhesion (vs. PET) is It was 1.0 N / 15 mm.

  The used OPP film (thickness 40 μm) was printed on the corona-treated side (Fine Star 632 white manufactured by Toyo Ink Manufacturing Co., Ltd.). The PET film (thickness 25 μm) was printed on the corona treatment side (Fine Star 632 White manufactured by Toyo Ink Manufacturing Co., Ltd.).

For each measurement of the alkali peelability, adhesive residue and adhesiveness (against PET), first a labeler OPERA2000RF15T manufactured by Sakumi Labeler Co., Ltd. was used at a speed of 80 bpm to a 2L long-angle PET bottle and a 50 μm thick OPP film. For the test in which the hot-melt pressure-sensitive adhesive composition was applied to a printed label with a coating amount of 20 to 30 mg / piece and applied with a coating area of 15 cm ² (temperature condition: 140 ° C.), and the wound label was adhered. A container was prepared and measurements were performed using this container.

<Alkali peelability>
The test container was pulverized to about 8 × 8 mm square to form a PET bottle pellet with a label. In a 1,000 ml round flask, 180 g of a 1.5 wt% sodium hydroxide aqueous solution and 20 g of the pellets were placed, and stirred at 250 rpm (stirring blade: propeller). After 15 minutes, it is filtered through a filter, the pellet is visually observed, the label is peeled off, and the hot melt adhesive composition does not remain in the PET bottle: ○, the label remains in the PET bottle, or the hot melt adhesive composition is When remaining in PET bottle or reattached: x.

<Adhesive residue>
When the label was manually peeled from the test container, it was determined whether the hot melt pressure-sensitive adhesive composition had adhered to the PET bottle. The test was carried out in a constant temperature and constant humidity at a temperature of 23 ° C. and a relative humidity of 65%. When the hot melt pressure-sensitive adhesive composition does not remain in the PET bottle: ◯, when the hot melt pressure-sensitive adhesive composition remains in the PET bottle: ×.

<Adhesion (vs. OPP): Label / Label Adhesion>
The measurement was performed by cutting a sample in which a hot melt pressure-sensitive adhesive was coated on the printing surface of an OPP film, cutting it to a width of 15 mm, affixing the sample to the OPP film, Degree angle peeling (peeling speed: 300 mm / min) was performed.
In addition, it will be (circle) if adhesive strength is 0.4 N / 15mm or more. More preferably, 1.0 N / 15 mm or more. If it is less than 0.4 N / 15 mm, it is x.

<Adhesiveness (to PET: Adhesive strength with label / PET bottle)>
The measurement was performed by cutting the test container with the label attached to a width of 15 mm, and performing 180 ° square peeling (peeling speed: 300 mm / min) in a constant temperature and humidity chamber at a temperature of 23 ° C. and a relative humidity of 65%.
In addition, it will be (circle) if adhesive strength is 0.4 N / 15mm or more. More preferably, 1.0 N / 15 mm or more. If it is less than 0.4 N / 15 mm, it is x.

<High speed peeling>
Measure the upper end of the label with your hand (strength of a 6 cm high label is about 0.3 seconds: peeling speed is about 1200 cm / min) and peel off the bonded part of the label / PET bottle and observe the peeled state. did. When the hot-melt pressure-sensitive adhesive composition did not adhere to the PET bottle: ○, when even a little adhered: evaluated as x.

Examples 2-9
Table 1 below shows thermoplastic elastomer (A), rosin-based tackifier (B), synthetic oil (C), wax (D) and polyethylene glycol (E) having a penetration of 10 ° C. or less at 25 ° C. In the same manner as in Example 1, the alkali dispersion type hot melt pressure-sensitive adhesive compositions of Examples 2 to 9 were prepared.

  The alkali dispersibility, adhesive residue, adhesiveness (adhesive strength) (against OPP and PET), and high-speed peelability of the alkali-dispersed hot-melt pressure-sensitive adhesive compositions of Examples 2 to 9 were the same as in Example 1. It was measured and evaluated by the method.

Comparative Example 1
<Method for producing alkali-dispersed hot melt pressure-sensitive adhesive composition>
A stainless beaker equipped with a stirrer is charged with 10 parts by weight of wax: A-C5120, terpene phenol resin; 5 parts by weight of T30, 10 parts by weight of refined coconut oil, and 30 parts by weight of tackifier; And melted. Heating was performed with care so that the contents would not be below 130 ° C and above 150 ° C. After melting, stirring is performed to obtain a uniform molten solution, and while maintaining the temperature at 150 ° C. or lower and continuing stirring, 10 parts by weight of thermoplastic elastomer; G1652 is gradually added to the melt. Tackifier: 35 parts by weight of Licarodin F was added to obtain a homogeneous melt mixture, and cooled to prepare an alkali-dispersed hot-melt pressure-sensitive adhesive composition.

  The alkali dispersibility hot-melt pressure-sensitive adhesive composition thus obtained was measured for alkali releasability, adhesive residue, adhesiveness (adhesive strength) (against OPP and PET), and high-speed releasability in the same manner as in Example 1. .

Comparative Example 2
In a stainless beaker equipped with a stirrer, 5 parts by weight of wax: A-C5180, terpene phenol resin; 5 parts by weight of T-30, 5 parts by weight of refined coconut oil, liquid rubber; 10 parts by weight of Hymol 4H and adhesive Giving agent: 30 parts by weight of Licarodin F was added and heated to melt. Heating was performed with care so that the contents did not exceed 150 ° C. After melting, stirring is performed to obtain a uniform molten solution, and while maintaining a temperature of 150 ° C. or lower and stirring is continued, 15 parts by weight of thermoplastic elastomer; G-1726 is gradually added to the melt, and then the adhesive is adhered. Giving agent: 30 parts by weight of licarrodin F was added to form a molten homogeneous mixture, and cooled to prepare an alkali-dispersed hot melt pressure-sensitive adhesive composition.

  The alkali dispersible hot-melt pressure-sensitive adhesive composition thus obtained has the same alkali releasability, adhesive residue, adhesiveness (adhesive strength) (against OPP and PET), and high-speed releasability in the same manner as in Example 1. It was measured.

Comparative Example 3
In a stainless beaker equipped with a stirrer, wax (D); 7 parts by weight of HNP-9, rosin-based tackifier (B); 21 parts by weight of licarrodin F, 6 parts by weight of polyethylene glycol: PEG-600 and synthetic oil : 32 parts by weight of PW90 was charged and heated to melt. Heating was performed with care so that the contents did not exceed 150 ° C. After melting, stirring is performed to obtain a homogeneous molten solution, and while maintaining the temperature at 150 ° C. or lower and continuing stirring, 10 parts by weight of thermoplastic elastomer; G-1650 is gradually added to the melt, and the addition is completed. A rosin-based tackifier (B); 24 parts by weight of KE-604 was added to obtain a homogeneous melt mixture, and cooled to prepare a hot melt pressure-sensitive adhesive composition.

  Further, the alkali releasability, adhesive residue adhesiveness (adhesive strength) (against OPP and PET) and high-speed releasability of the obtained alkali-dispersed hot-melt pressure-sensitive adhesive composition were measured in the same manner as in Example 1. did.

Comparative Example 4
A stainless beaker equipped with a stirrer was charged with 7 parts by weight of wax: 140F paraffin and 32 parts by weight of synthetic oil; PW90, and heated to melt. Heating was performed with care so that the contents did not exceed 150 ° C. After melting, stirring is performed to obtain a uniform molten solution, and while maintaining stirring at a temperature of 150 ° C. or lower and continuing stirring, 10 parts by weight of thermoplastic elastomer; G1650 is gradually added to the melt. A rosin-based tackifier; 51 parts by weight of Licarodin F was added to form a homogeneous melt mixture, and cooled to prepare an alkali-dispersed hot-melt pressure-sensitive adhesive composition.

  The alkali dispersible hot-melt pressure-sensitive adhesive composition thus obtained has the same alkali releasability, adhesive residue, adhesiveness (adhesive strength) (against OPP and PET), and high-speed releasability in the same manner as in Example 1. It was measured.

  Table 2 summarizes the compositions of the alkali-dispersed hot-melt pressure-sensitive adhesive compositions of Comparative Examples 1 to 4.

  From Table 1, the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention can peel off labels from PET bottles without adhesive residue, and has alkali peelability. It corresponds to A rank of. Further, when high-speed peeling was performed in consideration of practicality, the label could be peeled off from the PET bottle without any adhesive residue. On the other hand, from Table 2, the alkali-dispersed hot-melt pressure-sensitive adhesive compositions of Comparative Examples 1 to 4 left adhesive when the label was peeled off from the PET bottle, or the hot-melt pressure-sensitive adhesive became a PET bottle when peeled at high speed. Therefore, it can be seen that the recycling suitability of the PET recycling promotion council does not exceed B.

  As described above, the alkali-dispersed hot-melt pressure-sensitive adhesive composition of the present invention eliminates the need for containers after use, and labels are easily peeled off when recycled, and can be easily separated by immersion in a hot alkaline aqueous solution. It becomes possible. Moreover, it is known that the same performance is exhibited not only in PET bottles but also in glass containers, and is a hot melt adhesive suitable for recycling of glass containers.

Claims (9)

Thermoplastic elastomer (A), rosin tackifier (B) having an acid value of 100 mgKOH / g to 300 mgKOH / g, process oil (C) produced in petroleum refining, penetration at 25 ° C. of 10 dmm or less in it, the alkali dispersion synthetic polyethylene wax or oil 0.2 wt% paraffin wax (D), our and the number average molecular weight, characterized in that it comprises 1,000 to 60,000 of polyethylene glycol (E) Type hot melt pressure-sensitive adhesive composition (provided that the oil content in the paraffin wax is not included in the process oil (C)) . Wax (D) is, according to claim 1 an alkali dispersible hot melt adhesive composition, wherein it is a synthetic polyethylene wax. The alkali-dispersed hot-melt pressure-sensitive adhesive composition according to claim 1 or 2, wherein the wax (D) has a melting point of 60 ° C or higher and 135 ° C or lower. Thermoplastic elastomer (A), rosin tackifier (B) having an acid value of 100 mgKOH / g to 300 mgKOH / g, process oil (C) produced in petroleum refining, penetration at 25 ° C. of 10 dmm or less in the is, synthetic polyethylene wax or oil 0.2 wt% paraffin wax (D), and a number average molecular weight of 1,000 to 60,000 of polyethylene glycol (E) below 180 ° C. 90 ° C. above the temperature A method for producing an alkali-dispersed hot-melt pressure-sensitive adhesive composition characterized by blending. A container with a label, wherein a label is adhered to the container using the alkali-dispersed hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 3 . Container-out Labeled according to claim 5, characterized in that a polyethylene terephthalate container. The labeled container according to claim 5 or 6 , wherein the label substrate is made of a stretched polypropylene film. By coating the alkali-dispersible hot melt adhesive composition of the label to any one of claims 1 to 3, characterized in that applying labels to a container, a manufacturing method of the labeled container. The method for producing a labeled container according to claim 8 , wherein the alkali-dispersed hot melt pressure-sensitive adhesive composition is applied to the label printing surface.