Stripping agent

Abstract

To provide a release agent capable of peeling a label from a solid body to which the label is attached. [Solution] A release agent for removing labels affixed to solid objects contains the following components (A) to (D): Component (A): a saturated or unsaturated, linear or branched hydrocarbon having 5 to 17 carbon atoms and / or a saturated or unsaturated alicyclic hydrocarbon having 5 to 11 carbon atoms; Component (B): an alkyl glycoside; Component (C): a glyceryl ether; and Component (D): water.

Description

[Technical Field]

[0001] The present invention relates to a release agent for removing labels. [Background technology]

[0002] 2. Description of the Related Art There is known a technique for removing labels attached to solid objects such as containers for the purpose of recycling. For example, Patent Document 1 attempts to provide a label that can be easily peeled off from an object to which it is attached by providing a printed layer containing a heating element on the label itself. Furthermore, Patent Document 2 discloses an adhesive treatment liquid containing a liquid with a Hansen solubility parameter value of 31 and an alkaline compound, and attempts to provide a treatment liquid and an adhesive treatment method that can remove various types of adhesives. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-083116 [Patent Document 2] International Publication No. 2022-004609 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology of Patent Document 1 has the problem of increased label costs. Furthermore, the technology of Patent Document 2 has the problem of extremely high solvent costs because the main component of the processing solution is solvent-based. Also, there is a risk of fire or explosion, which necessitates the need for equipment to deal with such risks.

[0005] The present invention has been made in view of the above circumstances, and relates to providing a release agent that can release a label from a solid object to which the label is attached. [Means for solving the problem]

[0006] The present invention relates to the following [1] to

[11] . [1] A release agent for removing a label attached to a solid object, The release agent contains the following components (A) to (D): Component (A): saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water [2] The release agent according to [1] above, wherein the content of component (A) is 1.1% by mass or more and 50% by mass or less. [3] The stripping agent according to [1] or [2] above, further comprising the following component (E): Ingredient (E): Alkaline agent [4] A method for peeling off a label attached to a solid object, comprising: a contacting step of contacting the solid with a stripping agent at a temperature of 20°C or higher and 95°C or lower and The stripping method, wherein the stripping agent contains the following components (A) to (D): Component (A): saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water [5] The peeling method according to [4], further comprising a shredding step of shredding the solid before, during, and / or after the contacting step. [6] The stripping method according to [4] or [5] above, wherein the content of component (A) in the stripping agent is 1.1% by mass or more and 50% by mass or less. [7] The stripping method according to any one of the above [4] to [6], wherein the stripping agent further contains the following component (E): Ingredient (E): Alkaline agent [8] A recycling method for peeling off a label from a solid to which the label is attached and regenerating the solid as a recycled material, comprising: a contacting step of contacting the solid with a stripping agent at a temperature of 20°C or higher and 95°C or lower and The release agent contains the following components (A) to (D): Component (A): saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water [9] The recycling method according to [8], further comprising a shredding step of shredding the solid before, during, and / or after the contacting step.

[10] The recycling method according to [8] or [9], wherein the content of component (A) in the release agent is 1.1% by mass or more and 50% by mass or less.

[11] The recycling method according to any one of the above [8] to

[10] , wherein the release agent further contains the following component (E): Ingredient (E): Alkaline agent [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a release agent that can release a label from a solid body to which the label is attached. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Removal Agent of the Present Invention> The release agent of the present invention comprises A release agent for removing a label attached to a solid body, comprising: The release agent contains the following components (A) to (D). Component (A): saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water

[0009] One of the features of the present invention is that the use of such a release agent can provide a method for removing labels affixed to solids, a recycling method for regenerating solids as recycled raw materials, or a deinking agent for removing ink from labels on which characters or the like are printed.

[0010] 〔solid〕 In the present invention, a "solid" is an object having a surface to which a label can be attached, such as a container for storing liquid or powder, or a component of a mechanical device. Examples of solid materials include plastics, metals, and glass. From the viewpoint of recycling, plastics and metals are preferred, and plastics are more preferred. Among plastics, preferred examples include polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PSt). Specific examples of solids include polyethylene containers, polypropylene containers, polyethylene terephthalate containers, polystyrene containers, etc., and such containers are also suitable targets for label removal methods and recycling methods.

[0011] 〔label〕 The release agent of the present invention can be effectively applied to general labels, i.e., labels composed of a substrate used for printing or writing characters, etc., and an acrylic adhesive layer, a urethane adhesive layer, a silicone adhesive layer, or a rubber adhesive layer formed on the substrate. The release agent of the present invention is preferably used with acrylic adhesives. Examples of substrates include high-quality paper, kraft paper, Japanese paper, polyethylene films, polypropylene films, polyethylene terephthalate films, and polystyrene films.

[0012] [Removal performance] The release agent of the present invention has high release performance. In the present invention, the release performance of the release agent refers to the ability of the release agent to release a label attached to a solid, and the higher the release performance of the release agent, the shorter the time it takes to release the label.

[0013] The composition of the release agent will be described in detail below.

[0014] [Component (A)] Component (A) used in the present invention is a saturated or unsaturated, straight-chain or branched-chain hydrocarbon having 5 to 17 carbon atoms and / or a saturated or unsaturated alicyclic hydrocarbon having 5 to 11 carbon atoms. The component (A) may be used alone or in combination of two or more.

[0015] The carbon number of the saturated or unsaturated, straight-chain or branched-chain hydrocarbon having 5 to 17 carbon atoms is 5 or more from the viewpoint of release performance. On the other hand, from the same viewpoint, the carbon number is preferably 16 or less, more preferably 14 or less, and even more preferably 13 or less. Specific examples of such hydrocarbons include preferably pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tetradecane, hexadecane, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, 1-octene, 2-octene, 3-octene, 4-octene, 1-decene, 2-decene, 3-decene, 4-decene, 5-decene, 1-undecene, 2-undecene, 3-undecene, 4-undecene, decene, 5-undecene, 1-dodecene, 2-dodecene, 3-dodecene, 4-dodecene, 5-dodecene, 6-dodecene, 1-tetradecene, 2-tetradecene, 3-tetradecene, 4-tetradecene, 5-tetradecene, 6-tetradecene, 7-tetradecene, 1-hexadecene, 2-hexadecene, 3-hexadecene, 4-hexadecene, 5-hexadecene, 6-hexadecene, 7-hexadecene, 8-hexadecene, and the like. Among these, from the viewpoint of shortening the stripping time, hexane, octane, undecane, dodecane, tetradecane, hexadecane, 1-hexene, 1-octene, 1-undecene, 1-dodecene, 1-tetradecene, and 1-hexadecene are preferred, octane, undecane, dodecane, tetradecane, 1-octene, 1-undecene, 1-dodecene, and 1-tetradecene are more preferred, and hexane, octane, undecane, dodecane, 1-hexene, 1-octene, 1-undecene, and 1-dodecene are even more preferred.

[0016] The carbon number of the saturated or unsaturated alicyclic hydrocarbon having 5 to 11 carbon atoms is 5 or more from the viewpoint of release performance, while from the same viewpoint, the carbon number is 11 or less. Specific examples of such alicyclic hydrocarbons include cyclo compounds such as cyclopentane, cyclohexane, cyclooctane, cyclodecane, cyclopentene, cyclohexene, cyclooctene, and cyclodecene.

[0017] In addition to component (A), the present invention can also use aromatic hydrocarbons such as alkylbenzenes, such as nonylbenzene and dodecylbenzene, and naphthalene compounds, such as methylnaphthalene and dimethylnaphthalene.

[0018] In the release agent of the present invention, the content of component (A) is preferably 1.1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more from the viewpoint of release performance, and is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less from the viewpoint of cost.

[0019] When the release agent contains an alkaline agent as component (E) from the viewpoint of further improving release performance, the content of component (A) in the release agent is, from the viewpoint of release performance, preferably 0.005% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.02% by mass or more, and even more preferably 1.1% by mass or more, and from the viewpoint of cost, is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 17% by mass or less, and even more preferably 10% by mass or less.

[0020] [Component (B)] The alkyl glycoside of component (B) used in the present invention is represented by the following general formula (1): R 1 (OR 2 ) x G y (1) [In the formula, R 1represents a linear or branched alkyl group, alkenyl group, or alkylphenyl group having 8 to 18 carbon atoms; R 2 represents an alkylene group having 2 to 4 carbon atoms, G represents a residue derived from a reducing sugar having 5 or 6 carbon atoms, x (average value) represents 0 to 5, and y (average value) represents 1 to 5. In the formula, x is preferably 0 to 2, more preferably 0. y is preferably 1 to 1.5, more preferably 1 to 1.4. R 1 From the viewpoint of release performance, the number of carbon atoms is preferably 9 to 16, more preferably 10 to 14. Note that x and y are protons ( 1 Determined by H NMR.

[0021] The alkyl glycoside is not particularly limited as long as it satisfies the general formula (1), but from the viewpoint of obtaining higher peeling performance, preferred are decyl glycoside, dodecyl glycoside, myristyl glycoside, etc. Such alkyl glycosides are commercially available, and an example of dodecyl glycoside (lauryl glycoside) is Mydol 12 manufactured by Kao Corporation.

[0022] From the viewpoint of stripping performance, the content of alkyl glycoside in the release agent is 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 3% by mass or more, and from the viewpoint of cost, it is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0023] When the release agent contains an alkaline agent as component (E) to further enhance release performance, the content of alkyl glycoside in the release agent is, from the viewpoint of release performance, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.03% by mass or more, and even more preferably 0.1% by mass or more, and from the viewpoint of cost, is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0024] [Component (C)] From the viewpoint of release performance, the glyceryl ether of component (C) used in the present invention preferably includes one having a linear or branched alkyl or alkenyl group having from 4 to 22 carbon atoms. For example, one having an alkyl group having from 4 to 22 carbon atoms, such as n-butyl, isobutyl, n-hexyl, isohexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, isodecyl, stearyl, or isostearyl, is more preferred. More preferred are those having one or two, and especially one, alkyl group having from 5 to 20 carbon atoms, and even more preferred are those having from 8 to 18 carbon atoms.

[0025] Furthermore, as the glyceryl ether used in the present invention, a monoalkyl diglyceryl ether or a monoalkyl polyglyceryl ether in which preferably two or more, more preferably two to three glyceryl groups are linked by an ether bond can also be used. From the viewpoint of peeling performance, monoalkyl glyceryl ethers and monoalkyl diglyceryl ethers are preferred. These glyceryl ethers may be used alone or in combination. Particularly preferred glyceryl ethers are 2-ethylhexyl glyceryl ether, isodecyl glyceryl ether, and isostearyl glyceryl ether.

[0026] In the present invention, the use of such glyceryl ethers has the advantage that the dispersibility of organic components such as component (A) in water can be stabilized, thereby demonstrating high release performance.

[0027] The content of glyceryl ether in the release agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, from the viewpoint of release performance, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 7% by mass or less, from the viewpoint of release performance.

[0028] When the release agent contains an alkaline agent as component (E) to further enhance release performance, the content of alkyl glycoside in the release agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, from the viewpoint of release performance, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 7% by mass or less, from the viewpoint of release performance.

[0029] In the release agent of the present invention, from the viewpoint of stably dispersing component (A) and water, the mass ratio of alkyl glycoside to glyceryl ether (B / C) is preferably 0.20 or more, more preferably 1 or more, and even more preferably 3 or more. From the viewpoint of suppressing foaming during use of the release agent, it is preferably 18 or less, more preferably 10 or less, and even more preferably 6 or less.

[0030] When component (E) is contained from the viewpoint of further improving the release performance, the mass ratio (B / C) is, from the same viewpoint, preferably 0.2 or more, more preferably 0.25 or more, even more preferably 0.3 or more, and even more preferably 0.4 or more, and from the same viewpoint, is also preferably 20 or less, more preferably 15 or less, and even more preferably 12 or less.

[0031] [Component (D)] The water used in the present invention as [component (D)] is not particularly limited, and examples thereof include tap water, ion-exchanged water, and pure water. The water content in the release agent is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more from the viewpoints of safety and release performance, while it is preferably 97% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less from the viewpoint of release performance.

[0032] From the viewpoint of safety, the mass ratio (D / A) of component (D) to component (A) is preferably at least 2, more preferably at least 3, and even more preferably at least 4. From the same viewpoint, it is preferably at most 50, more preferably at most 45, even more preferably at most 30, and even more preferably at most 15.

[0033] When the release agent contains an alkaline agent as component (E) from the viewpoint of further improving the release performance, the water content in the release agent is preferably 40% by mass or more, more preferably 50% by mass or more, from the viewpoints of safety and release performance, and is preferably 97% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, from the viewpoint of release performance.

[0034] In the present invention, from the viewpoint of release performance, a preferred combination of components (A), (B) and (C) is a combination in which component (A) is one or more selected from the group consisting of 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, 1-octene, 2-octene, 3-octene, 4-octene, 1-decene, 2-decene, 3-decene, 4-decene, 5-decene, 1-dodecene, 2-dodecene, 3-dodecene, 4-dodecene, 5-dodecene, 6-dodecene, pentane, hexane, octane, decane and dodecane; component (B) is decyl glycoside and / or dodecyl glycoside; and component (C) is one or more selected from the group consisting of 2-ethylhexyl glyceryl ether, isodecyl glyceryl ether and isostearyl glyceryl ether.

[0035] [Component (E)] From the viewpoint of obtaining a higher stripping effect, the stripping agent of the present invention preferably contains an alkali agent as component (E). The alkaline agent used in the present invention can be any water-soluble alkaline agent. Specific examples include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; silicates such as sodium orthosilicate, sodium metasilicate, and sodium sesquisilicate (e.g., No. 1 sodium silicate, No. 2 sodium silicate, and No. 3 sodium silicate); phosphates such as sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, and sodium hexametaphosphate; carbonates such as disodium carbonate, sodium bicarbonate, dipotassium carbonate, and potassium bicarbonate; borates such as sodium borate; amine compounds such as monoethanolamine; and quaternary ammonium salts such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, choline hydroxide, hexadecylammonium hydroxide, phenyltrimethylammonium hydroxide, benzyltrimethylammonium hydroxide, and N,N,N-trimethyladamantylammonium hydroxide. Two or more alkaline agents may be used in combination as component (E). Of these alkaline agents, sodium hydroxide, potassium hydroxide, sodium orthosilicate, sodium metasilicate, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide are preferred.

[0036] The addition of an alkaline agent to the stripping agent of the present invention can shorten the stripping time. That is, the content of the alkaline agent in the stripping agent is preferably 0.01% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.5% by mass or more from the viewpoint of shortening the stripping time, and is preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 5% by mass or less from the viewpoint of cost and safety.

[0037] Adding an alkaline agent to the release agent of the present invention can further enhance the deinking effect. From the viewpoint of achieving a higher deinking effect, the content of the alkaline agent in the release agent is preferably 3% by mass or more, more preferably 3.5% by mass or more, and even more preferably 10% by mass or more, and from the viewpoints of cost and safety, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0038] In the present invention, the "deinking effect" refers to the effect of removing ink from a label to the extent that the characters and patterns printed on the label become unrecognizable to the naked eye. The higher the deinking effect of the stripping agent or deinking agent of the present invention, the shorter the time it takes to remove ink from the label.

[0039] From the viewpoint of shortening the peeling time, the mass ratio (E / A) of component (E) to component (A) is preferably at least 0.001, more preferably at least 0.5, and even more preferably at least 1. The greater the content of component (E), the shorter the peeling time and deinking time. However, from the viewpoint of cost and safety, the mass ratio is preferably at most 4, more preferably at most 3.5, and even more preferably at most 3.

[0040] [Lower alcohol] From the viewpoint of formulation stability, the release agent of the present invention may contain a lower alcohol, for example, an alcohol having 1 to 6 carbon atoms, preferably an alcohol having 1 to 3 carbon atoms. Specific examples of such alcohols include methanol, ethanol, and propanol.

[0041] The content of the lower alcohol in the release agent is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and even more preferably 0.2% by mass or more, from the viewpoint of formulation stability, and is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, from the viewpoint of cost.

[0042] [Other ingredients] The release agent of the present invention may contain a chelating agent, a water-soluble polymeric carboxylic acid, a glycol ether such as ethylene glycol monoalkyl ether, a solubilizing agent such as a fatty acid and its salt, or an alkyl sulfate and its salt, a slurrying agent, an antifoaming agent, an antiseptic, an antirust agent, and the like.

[0043] [pH of stripper] The pH of the stripping agent of the present invention is not particularly limited, but from the viewpoint of shortening the stripping time, it is preferably 6 or more at 25° C., more preferably 8 or more, and even more preferably 11 or more. On the other hand, from the viewpoint of user safety, the upper limit of the pH is preferably 15 or less at 25° C., more preferably 14.5 or less, and even more preferably 14 or less.

[0044] The release agent of the present invention having the above-mentioned constitution can be produced by mixing the above-mentioned components and optional components by a conventional method. The stripping agent of the present invention can also be produced as a concentrated product and diluted with an aqueous medium such as water before use. Such a stripping agent of the present invention contains a component other than the solvent (for example, water) as an essential component, and is therefore expected to be safer to use.

[0045] <Label Peeling Method of the Present Invention> The label peeling method of the present invention comprises the steps of: A method for removing a label attached to a solid body, comprising the steps of: a contacting step of contacting the solid with a stripping agent at a temperature of 20°C or higher and 95°C or lower and The release agent contains the following components (A) to (D), and is a release agent for a release method. Component (A): saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water

[0046] [Contact process] The stripping agent used in the contacting step is the same as the stripping agent of the present invention described above. In the contacting step, the solid is brought into contact with the release agent. Specific operations for the contacting step include general operations for bringing a liquid into contact with a solid, such as immersing the solid in the release agent, impregnating the solid with the release agent, stirring the solid after immersion or impregnation, or vibrating the solid by applying ultrasonic waves after immersion or impregnation.

[0047] In the contacting step, the temperature of the release agent is set to 20° C. or higher and 95° C. or lower. From the viewpoint of the release effect, the temperature is preferably 30° C. or higher, more preferably 50° C. or higher. From the viewpoint of reducing heating costs, the temperature is preferably 90° C. or lower, more preferably 80° C. or lower.

[0048] The contact time is preferably 3 minutes or more, more preferably 10 minutes or more, and even more preferably 60 minutes or more from the viewpoint of peeling performance, and is preferably 10 hours or less, more preferably 5 hours or less, and even more preferably 3 hours or less from the viewpoint of reducing heating costs.

[0049] Examples of equipment for carrying out such a contact step include a tank equipped with a motor with stirring blades, a tank equipped with an ultrasonic generator, and a device capable of shaking the tank.

[0050] [Shredding process] The peeling method of the present invention preferably further comprises a shredding step of shredding the solid before, during, and / or after the contacting step, which can improve peeling efficiency and recycling efficiency.

[0051] Examples of equipment for carrying out the shredding step include a general shredding machine. A wet shredding machine such as a wet shredding pump or a colloid mill may be used. By using a wet shredding machine, the shredding step and the contact step can be carried out simultaneously.

[0052] <Recycling method of the present invention> The recycling method of the present invention comprises: A recycling method for regenerating a solid material by peeling off a label from the solid material to which the label is attached, the method comprising: a contacting step of contacting the solid with a stripping agent at a temperature of 20°C or higher and 95°C or lower and The release agent is a recycling method containing the following components (A) to (D). Component (A): saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water

[0053] The contacting step is the same as the contacting step in the label peeling method of the present invention described above. The release agent used in the contacting step is the same as the release agent of the present invention described above.

[0054] From the viewpoint of improving the recycling efficiency, it is preferable to have a shredding step of shredding the solid before, during, and / or after the contacting step. The shredding step is the same as the shredding step in the label peeling method of the present invention described above.

[0055] By carrying out a recovery step on the material to be treated after the contact step or after the shredding step which is carried out after the contact step, the solid can be regenerated as a recycled material. Examples of recovery processes include flotation separation using water, wind separation using wind, and electrostatic separation using the inherent charging properties of plastics. These methods can be used alone or in combination to form the recovery process. By flotation separation, labels attached with adhesive can be separated from solid materials such as plastic, metal, and glass, and then recovered. Because labels are light, by supplying air to the material to be treated after the contact process or shredding process and adjusting the air volume, the labels can be separated from the solids and solids such as plastic, metal, and glass can be recovered. Furthermore, the recovered plastic can be separated into different plastic materials by utilizing their specific gravity. In this case, by using an isopropanol solution instead of water to make the specific gravity of the medium less than 1, it is possible to separate and recover, for example, polypropylene (PP) and polyethylene (PE). Alternatively, the recovered plastic can be irradiated with infrared light, and the difference in infrared absorption can be utilized to separate and recover polypropylene (PP) and polyethylene (PE). [Example]

[0056] The present invention will be specifically explained below by showing examples, but the present invention is not limited to the following examples. Unless otherwise specified, the numerical values ​​for the amounts of each component in the tables are in mass%. As a result of rounding, the total mass% of each component may not add up to 100%.

[0057] Example 1 The release agent of Example 1 was prepared by mixing 1-dodecene as component (A), alkyl glycoside 1 (in the above general formula (1), x = 0 and y = 1.3) having an average alkyl chain carbon number of 11.3 as component (B), 2-ethylhexyl glyceryl ether as component (C), and water as component (D), as well as ethanol and sodium hydroxide. The specific composition is as shown in Table 1.

[0058] Examples 2 to 8 The release agents of Examples 2 to 8 were prepared using the components and compositions shown in Table 1. In Example 8, the release agent was prepared without adding sodium hydroxide.

[0059] Test Example An empty container (container body: polyethylene; label: polypropylene; adhesive: acrylic adhesive) that had contained a commercial liquid detergent was washed briefly inside and out with water and air-dried. The labeled portion of the container was then shredded into pieces approximately 5 mm x 5 mm in size to prepare test specimens. 100 g of the release agent to be evaluated and one magnetic stirrer piece having a length of 30 mm were placed in a glass screw tube, and the tube was then capped. The screw tube containing the stripping solution was placed in a water bath at 70°C, and the contents of the screw tube were stirred at 700 rpm for 1 hour while maintaining the water temperature (immersion temperature) at 70°C. After stirring, 10 test pieces (approximately 0.2 g) were placed in the screw cap tube and the cap was closed. Then, stirring was carried out at 700 rpm in water at 70°C. The condition inside the screw tube was visually observed every hour, and the label removal effect of the release agent and the deinking effect of the printed part of the label were judged according to the following criteria.

[0060] [Label peeling effect] The inside of the screw tube was checked every hour. The time until all 10 test specimen labels peeled off was recorded as the "peeling time." If the "peeling time" exceeded 5 hours, it was recorded as ">5."

[0061] [De-inking effect] The inside of the screw tube was checked every hour. A label was judged to be deinked when the printed characters and patterns could no longer be visually confirmed, regardless of whether the label peeled off or not. The time required for all 10 test pieces to become deinked labels was recorded as the "deinking time." If the "deinking time" exceeded 5 hours, it was recorded as ">5."

[0062] The composition of each stripping solution, as well as the main test conditions and results, are summarized in Table 1. Table 1 also lists the pH measurement results of the stripping solutions at 25°C and the mass ratio (E / A) of component (E) to component (A) in the stripping agent.

[0063] [Table 1]

[0064] From Table 1, it was found that the release agent of the present invention has an excellent release effect over a wide pH range. Furthermore, it was found that the higher the pH value of the release agent at 25°C, the shorter the release time and the stronger the deinking effect. It was also found that the release agent of the present invention can be used to realize a label peeling method and a label recycling method.

[0065] Reference example 1 5 parts by mass of sodium hydroxide and 95 parts by mass of water were mixed to prepare the release agent of Reference Example 1. This release agent did not contain component (A), component (B), or component (C). Using this release agent, we tested its label removal and deinking effects under the same conditions and methods as above. As a result, after 5 hours of stirring, the label removal and deinking effects were insufficient.

[0066] Examples 9 to 49 and Comparative Examples 1 to 4, 8, and 9 The release agents of Examples 9 to 49 and Comparative Examples 1 to 4, 8, and 9 were prepared using the components and compositions shown in Tables 2 to 11. Tests were then conducted in the same manner as in the above test examples at the water temperatures (immersion temperatures) shown in Tables 2 to 11.

[0067] [Table 2]

[0068] Table 2 shows that the release agents of the present invention, which contain saturated hydrocarbons with various carbon numbers, all exhibit excellent label removal and deinking effects. On the other hand, the release agent of Comparative Example 1 was found to be effective in deinking, but four sheets had not been removed after five hours, so it was determined to have a weak label removal effect.

[0069] [Table 3]

[0070] Table 3 shows that the release agents of the present invention, which contain unsaturated hydrocarbons with various carbon numbers, all exhibit excellent label removal and deinking effects. On the other hand, the release agent of Comparative Example 2 showed a deinking effect, but its label removal effect was weak.

[0071] [Table 4]

[0072] From Table 4, it was found that the release agents of Comparative Examples 3 and 4 were effective in removing ink, but were weak in label removal effect.

[0073] [Table 5]

[0074] Table 5 shows that the release agent of the present invention exhibits excellent label peeling effects even at immersion temperatures of 30 to 50° C. Furthermore, Table 5 shows that the fewer the carbon number of the hydrocarbon of component (A), the more likely it is that the release agent will exhibit excellent label peeling effects even at lower immersion temperatures.

[0075] [Table 6]

[0076] Table 6 shows that component (A) exhibits excellent label peeling and deinking effects over a wide range of content. The mass ratio (A / B) of component (A) to component (B) in the release agent and the mass ratio (D / A) of component (D) to component (A) in the release agent are also shown in Table 6.

[0077] [Table 7]

[0078] In Example 31, alkyl glycoside 2 (in the above general formula (1), x=0 and y=1.3) having an average alkyl chain carbon number of 10.2 was used as component (B). Table 7 shows that even when alkyl glycosides having various structures are blended as component (B), the release agent of the present invention still exhibits excellent label peeling and deinking effects.

[0079] [Table 8]

[0080] Table 8 shows that component (B) exhibits excellent label peeling and deinking effects over a wide range of content. The mass ratio (B / C) of component (B) to component (C) in the release agent is also shown in Table 8.

[0081] [Table 9]

[0082] In Example 38, isodecyl glyceryl ether was used as component (C), and in Example 39, isostearyl glyceryl ether was used as component (C) to prepare the release agent. Table 9 shows that even when a glyceryl ether having a structure other than 2-ethylhexyl glyceryl ether is blended as component (C), the release agent of the present invention still exhibits excellent label peeling and deinking effects.

[0083] [Table 10]

[0084] Table 10 shows that component (C) exhibits excellent label peeling and deinking effects over a wide range of content. The mass ratio (B / C) of component (B) to component (C) in the release agent is also shown in Table 6.

[0085] [Table 11]

[0086] In Examples 44 to 49, stripping agents were prepared using various alkaline agents instead of sodium hydroxide as component (E). Table 11 shows that the release agents of the present invention exhibit excellent label peeling effects even when various alkaline agents are used as component (E). Furthermore, it was found that the release agents of Examples 44 and 46 to 49 all exhibit excellent deinking effects. [Industrial Applicability]

[0087] The release agent of the present invention can be used in the field of removing labels from containers and recycling the containers and labels.

Claims

1. A release agent for removing a label attached to a solid body, comprising: The release agent contains the following components (A) to (D): Component (A): Saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water

2. 2. The release agent according to claim 1, wherein the content of component (A) is 1.1% by mass or more and 50% by mass or less.

3. The release agent according to claim 1, further comprising the following component (E): Component (E): Alkaline agent

4. A method for removing a label attached to a solid body, comprising the steps of: a contacting step of contacting the solid with a stripping agent at a temperature of 20°C or higher and 95°C or lower and The stripping method, wherein the stripping agent contains the following components (A) to (D): Component (A): Saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water

5. The method according to claim 4 , further comprising a shredding step of shredding the solid before, during, and / or after the contacting step.

6. The stripping method according to claim 4, wherein the content of component (A) in the stripping agent is 1.1% by mass or more and 50% by mass or less.

7. 5. The stripping method according to claim 4, wherein the stripping agent further comprises the following component (E): Component (E): Alkaline agent

8. A recycling method for regenerating a solid material by peeling off a label from the solid material to which the label is attached, the method comprising: a contacting step of contacting the solid with a stripping agent at a temperature of 20°C or higher and 95°C or lower and The release agent contains the following components (A) to (D): Component (A): Saturated or unsaturated, straight-chain or branched-chain hydrocarbons having 5 to 17 carbon atoms and / or saturated or unsaturated alicyclic hydrocarbons having 5 to 11 carbon atoms Component (B): Alkyl glycoside Ingredient (C): Glyceryl ether Ingredient (D): Water

9. 9. The recycling method according to claim 8, further comprising a shredding step of shredding the solid before, during, and / or after the contacting step.

10. The recycling method according to claim 8, wherein the content of component (A) in the release agent is 1.1% by mass or more and 50% by mass or less.

11. 9. The recycling method according to claim 8, wherein the release agent further contains the following component (E): Component (E): Alkaline agent

Images