CN111826020A - Coating film remover and method for removing coating film - Google Patents
Coating film remover and method for removing coating film Download PDFInfo
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- CN111826020A CN111826020A CN202010196144.4A CN202010196144A CN111826020A CN 111826020 A CN111826020 A CN 111826020A CN 202010196144 A CN202010196144 A CN 202010196144A CN 111826020 A CN111826020 A CN 111826020A
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Abstract
The technical problem of the present invention is to provide a coating film remover and a coating film removing method which have excellent peeling performance and are suitable for recycling. The invention relates to a coating film remover for removing a coating film provided on a surface of a substrate, the coating film remover comprising an aromatic alcohol represented by the following formula (1) and water, wherein the content of the water is 10 to 94% by mass relative to the total amount of the coating film remover.
Description
Technical Field
The present invention relates to a coating film remover and a method for removing a coating film.
Background
Coating of an object to be coated such as a door of an automobile is generally performed in a state where the object to be coated is fixed to a fixing jig or a movable jig (a stopper jig or the like) for coating. Such coating using a coating jig tends to be as follows: when the coating is performed a plurality of times, the coating material adheres to the coating jig. When the coating material adheres to the coating jig and is cured, for example, in electrostatic coating, the coating jig may cause conduction failure. Therefore, the coating material (hereinafter, sometimes referred to as "coating film") adhering to the coating jig needs to be periodically peeled off.
Jp 2009-203403 a discloses a water-based release agent for coating films, which is characterized by adding a corrosion-inhibiting additive component containing 5 to 90 wt% of a monovalent or divalent alcohol solvent, 5 wt% or more of water, and 0.01 to 10 wt% of a gluconate salt as a corrosion-inhibiting additive component so that an iron-based material does not rust even when used at high temperatures.
Japanese patent application laid-open No. 5-279607 discloses a coating film remover of a thermosetting resin adhered to a metal surface, which comprises a liquid containing 70 to 100 wt% of N-methyl-2-pyrrolidone and 0 to 30 wt% of water.
In recent years, the level of requirements for coating quality (reduction in gloss, brightness, coating defects, and the like) has increased. For example, a coating film attached to a coating jig may fall off or scatter and adhere to a coating object, and it is required to reduce coating defects due to such foreign matter. In order to reduce the above-mentioned coating defects, it is required to clean the coating jig every time the coating is performed, and development of a coating film remover capable of removing a coating film in a shorter time than before has been desired.
Disclosure of Invention
The present invention has been made in view of the above circumstances, and an object thereof is to provide a coating film releasing agent and a coating film releasing method which have excellent releasability and are suitable for recycling.
The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that a coating film remover containing an aromatic alcohol having a specific structure and water is excellent in releasability and suitable for recycling. Namely, the present invention is as follows.
[1] A coating film remover for removing a coating film provided on the surface of a substrate, the coating film remover comprising an aromatic alcohol represented by the following formula (1) and water, wherein the content of the water is 10 to 94% by mass relative to the total amount of the coating film remover.
(in the formula (1), L represents a divalent hydrocarbon group having 1-6 carbon atoms, R represents a hydrogen atom or a hydrocarbon group having 1-3 carbon atoms, and-CH contained in the divalent hydrocarbon group2-is optionally substituted by-O-. )
[2] The coating film-releasing agent according to [1], which comprises: an organic phase containing the aromatic alcohol; and an aqueous phase containing the water, wherein the coating film remover is separated into at least two layers including a first layer composed of the organic phase and a second layer composed of the aqueous phase when the coating film remover is left to stand at a temperature at which the coating film is removed.
[3] The coating film-releasing agent according to [1] or [2], wherein the total of the content of the aromatic alcohol and the content of the water is 90% by mass or more and 100% by mass or less with respect to the total amount of the coating film-releasing agent.
[4] The coating film-releasing agent according to [1] or [2], wherein the content ratio of each of the cellulose derivative, the inorganic alkali compound and the peroxide is more than 0% by mass and 0.01% by mass or less with respect to the total amount of the coating film-releasing agent.
[5] The coating film-releasing agent according to [1] or [2], which does not contain the cellulose derivative, the inorganic basic compound and the peroxide.
[6] The coating film-releasing agent according to [1] or [2], wherein L represents an alkylene group having 1 to 3 carbon atoms, and R represents a hydrogen atom.
[7] The coating film releasing agent according to [1] or [2], wherein the aromatic alcohol contains at least one compound selected from the group consisting of benzyl alcohol, 4-isopropylbenzyl alcohol, 1-phenylethanol, phenethyl alcohol, γ -phenylpropyl alcohol, α -dimethylphenylethanol, 1-phenyl-1-propanol, cinnamyl alcohol, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, and ethylene glycol monobenzyl ether.
[8] The coating film-stripping agent according to [1] or [2], further comprising an aliphatic hydrocarbon having 4 to 12 carbon atoms.
[9] A method for removing a coating film provided on a surface of a substrate, the method comprising: bringing the coating film-releasing agent of [1] or [2] into contact with the coating film.
The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Drawings
Fig. 1 is a schematic view (top) illustrating a peeling mechanism in the case of using a conventional coating film peeling agent and a photograph (bottom) of a treatment liquid (including a coating film peeling agent and a coating film) after the peeling treatment.
Fig. 2 is a schematic view (top) illustrating a mechanism of peeling in the case of using the coating film peeling agent of the present embodiment and a photograph (bottom) of a treatment liquid (including the coating film peeling agent and the coating film) after the peeling treatment.
Fig. 3 is a graph showing a correlation between a moisture content ratio in a coating film peeling agent and peeling properties.
FIG. 4 is a graph showing the correlation between the content of the coating solid content in the coating film-peeling agent and the peeling property.
FIG. 5 is a photograph showing the change with time of the coating film remover of sample No. 3-1 of the example and the coating film remover of sample No. 3-12 of the comparative example after stirring and standing.
Detailed Description
An embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described below. However, the present embodiment is not limited to this. The expression "X to Y" in the present specification means the upper limit and the lower limit of the range (i.e., X or more and Y or less). When no unit is described in X and only a unit is described in Y, the unit of X is the same as the unit of Y.
Coating film-peeling agent
The coating film remover of the present embodiment is a coating film remover for removing a coating film provided on a surface of a substrate, the coating film remover comprising an aromatic alcohol represented by the following formula (1) and water, the water content being 10 to 94% by mass relative to the total amount of the coating film remover. In the formula (1), L represents divalent hydrocarbon group with 1-6 carbon atoms, R represents hydrogen atom or hydrocarbon group with 1-3 carbon atoms, and-CH contained in the divalent hydrocarbon group2-is optionally substituted by-O-.
The coating film-peeling agent is used for peeling a coating film provided on the surface of a substrate. The substrate may be any substrate as long as it is a material generally used. Examples of the material of the substrate include: metals such as iron, SUS and aluminum; and resins such as nylon, polypropylene (PP), Polyethylene (PE), acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polyether ether ketone (PEEK), polytetrafluoroethylene (teflon (registered trademark)), polybutylene terephthalate (PBT), and epoxy resin.
The coating film provided on the surface of the substrate may be any coating film as long as it is derived from a coating material that is generally used. Examples of the coating material include: polyester resin coatings, polyurethane resin coatings, acrylic resin coatings, epoxy resin coatings, alkyd melamine resin coatings, nitrocellulose-based coatings, and the like.
The coating film may be provided directly on the substrate. When the surface of the base material is rough, the coating film may be provided on the base material through a precoat layer such as a metal plating layer (Ni, Sn, Cr, Cu, etc.) or a coating layer of a resin material different in kind from the coating film.
< aromatic alcohol >
The coating film remover contains an aromatic alcohol. The aromatic alcohol is represented by the formula (1). The aromatic alcohol can be synthesized from a known starting material by a known method. The aromatic alcohol may be a commercially available one as it is.
In the formula (1), L represents a divalent hydrocarbon group having 1 to 6 carbon atoms. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. -CH-contained in the above divalent hydrocarbon group2-is optionally substituted by-O-. -CH-contained in the above divalent hydrocarbon group2When the alkyl group is substituted by-O-, the number of carbon atoms before the substitution is defined as the number of carbon atoms of the hydrocarbon group.
L is preferably selected from the group consisting of- (CH)2)n- (n is an integer of 1 to 6, preferably 1 to 3), - (O-C)2H4)m- (m is an integer of 1 or 2), -CH2－、－CH2－C(CH3)2－、－CH(CH3) -and-CH2－O－C2H4-divalent radicals of the group consisting. L is more preferably- (CH)2)nA divalent group represented by- (n is an integer of 1 to 3).
In the formula (1), R represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. R is preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group or an isopropyl group. More preferably, R is a hydrogen atom.
In one aspect of the present embodiment, in the formula (1), L preferably represents an alkylene group having 1 to 3 carbon atoms (i.e., - (CH)2)n- (n is an integer of 1 to 3)), wherein R represents a hydrogen atom.
The aromatic alcohol preferably contains at least one compound selected from the group consisting of benzyl alcohol, 4-isopropylbenzyl alcohol, 1-phenylethanol, phenethyl alcohol, γ -phenylpropyl alcohol, α -dimethylphenylethanol, 1-phenyl-1-propanol, cinnamyl alcohol, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, and ethylene glycol monobenzyl ether. The aromatic alcohol more preferably contains benzyl alcohol. The structural formula of the aromatic alcohol is shown below.
The content ratio of the aromatic alcohol is preferably 6 to 90% by mass, more preferably 10 to 87% by mass, even more preferably 10 to 85% by mass, even more preferably 15 to 80% by mass, and particularly preferably 20 to 70% by mass, based on the total amount of the coating film peeling agent. By setting in this way, a coating film releasing agent having more excellent releasability is obtained. The content ratio of the aromatic alcohol can be determined by analysis by gas chromatography. The conditions for analysis by gas chromatography are as follows.
The device comprises the following steps: gas chromatograph GC-14B (Shimadzu Kagaku Co., Ltd.)
A detector: thermal Conductivity Detector (TCD)
A chromatographic column: thermon-3000 (from Xinhe chemical company)
Temperature of the gasification chamber: 160 deg.C
Detector temperature: 160 deg.C
< water >)
The coating film remover contains water. The water is not particularly limited as long as it is water, tap water, well water, or the like, which is used as a raw material for various industrial products. The water may be distilled water or ion-exchanged water. In one aspect of the present embodiment, the water may have an electrical conductivity of 1 to 300. mu.S/cm, or 1 to 100. mu.S/cm.
The content of the water is 10 to 94% by mass, preferably 13 to 90% by mass, more preferably 15 to 90% by mass, even more preferably 20 to 85% by mass, and even more preferably 30 to 80% by mass, based on the total amount of the coating film peeling agent. By setting in this way, a coating film releasing agent having more excellent releasability is obtained. The water content can be determined by analysis using a karl fischer moisture meter. The conditions for analysis using a karl fischer moisture meter are as follows.
Analytical conditions for Karl Fischer moisture meter
The device comprises the following steps: karl Fischer moisture meter MKS-500 (Kyoto electronic industries Co., Ltd.)
The determination method comprises the following steps: volumetric titration method
Measuring temperature: 20 deg.C
In one aspect of the present embodiment, the total of the content of the aromatic alcohol and the content of the water is preferably 90% by mass or more and 100% by mass or less, and more preferably 99.9% by mass or more and 100% by mass or less, with respect to the total amount of the coating film peeling agent. In the present embodiment, the coating film remover may be composed of only the aromatic alcohol represented by the formula (1) and water.
< aliphatic Hydrocarbon >
The coating film remover preferably further comprises an aliphatic hydrocarbon having 4 to 12 carbon atoms, and more preferably further comprises an aliphatic hydrocarbon having 4 to 8 carbon atoms. By setting in this way, a coating film remover having more excellent releasability depending on the type of the object to be peeled is obtained. Examples of the aliphatic hydrocarbon having 4 to 12 carbon atoms include: butane, pentane, hexane, isohexane, heptane, octane, nonane, decane, undecane, dodecane, and the like. The coating film remover more preferably contains at least one compound selected from the group consisting of hexane, isohexane, and heptane. The aliphatic hydrocarbon having 4 to 12 carbon atoms is contained in an aromatic alcohol-containing organic phase (sometimes referred to as a "first organic phase") described below, or forms a second organic phase (a phase different from the aromatic alcohol-containing organic phase).
The content ratio of the aliphatic hydrocarbon having 4 to 12 carbon atoms is preferably 1 to 10% by mass, more preferably 3 to 6% by mass, based on the total amount of the coating film peeling agent.
< cellulose derivative, inorganic basic compound and peroxide >
In one aspect of the present embodiment, in the coating film peeling agent, the content ratio of each of the cellulose derivative, the inorganic base compound, and the peroxide is preferably more than 0% by mass and 0.01% by mass or less with respect to the total amount of the coating film peeling agent. When the content ratio of the cellulose derivative is in the above range, stable emulsification of the coating film remover is suppressed, and excellent peelability can be maintained. By setting the content ratio of the inorganic basic compound in the above range, hydrolysis of the coating film in the peeling treatment is suppressed. Further, by setting the content ratio of the inorganic basic compound to the above range, the coating film remover does not belong to the "japanese poison and hypertonic poison elimination method" poison and hypertonic poison. That is, the coating film remover is understood to improve the safety in handling. By setting the content of the peroxide to the above range, the coating film-peeling agent does not belong to the "japanese poison and high poison elimination method" and the high poison. That is, the coating film remover is understood to improve the safety in handling (for example, to suppress adverse effects on the human body). In one aspect of the present embodiment, the coating film peeling agent preferably does not contain the cellulose derivative, the inorganic basic compound, and the peroxide.
(cellulose derivative)
In the present embodiment, examples of the cellulose derivative include: methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, butyl cellulose, propyl cellulose, and the like. That is, the coating film peeling agent preferably does not contain methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, butylcellulose, and propylcellulose.
In one aspect of the present embodiment, the coating film peeling agent preferably does not contain at least one cellulose derivative selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, butyl cellulose, and propyl cellulose.
(inorganic base Compound)
In the present embodiment, examples of the inorganic basic compound include: sodium hydroxide (caustic soda), potassium hydroxide (caustic potash), lithium hydroxide, cesium hydroxide, calcium hydroxide, and the like. That is, the coating film peeling agent preferably does not contain sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, and calcium hydroxide.
In one aspect of the present embodiment, the coating film peeling agent preferably does not contain at least one inorganic basic compound selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, and calcium hydroxide.
(peroxide)
In the present embodiment, examples of the peroxide include: hydrogen peroxide, urea peroxide, peracetic acid, and the like. That is, the coating film remover preferably does not contain hydrogen peroxide, urea peroxide, or peracetic acid.
In one aspect of the present embodiment, the coating film-peeling agent preferably does not contain at least one peroxide selected from the group consisting of hydrogen peroxide, urea peroxide, and peracetic acid.
< other ingredients >
The coating film-releasing agent of the present embodiment may further contain other components within a range that can achieve the effects of the present invention. Examples of the other components include: surfactants, rust inhibitors, pH adjusters, chelating agents, thickeners, wetting agents, evaporation inhibitors, antioxidants, ultraviolet absorbers, pigments, perfumes, preservatives and the like.
< Properties of coating film Release agent >
In one aspect of the present embodiment, the coating film remover may be understood to include an organic phase (first organic phase) containing the aromatic alcohol and an aqueous phase containing the water. Preferably, the coating film-releasing agent separates into at least two layers including a first layer composed of the organic phase and a second layer composed of the aqueous phase when left standing at a temperature at which the coating film is released. Here, the "temperature at which the coating film is peeled" means a temperature of the coating film peeling agent at which the coating film can be peeled off in the peeling treatment. The temperature may be, for example, 20 to 120 ℃, 30 to 80 ℃, or 40 to 70 ℃. The term "when left alone" means that the coating film remover is maintained for 4 hours in a state of not receiving an external force other than gravity. More specifically, the term "at the time of standing" refers to a time when the coating film remover is not shaken, rotated, or stirred for 4 hours. The coating film remover is different from an emulsified coating film remover in that the coating film remover separates into at least two or more layers including a first layer composed of the organic phase and a second layer composed of the aqueous phase when left standing at a temperature at which the coating film is removed. Here, the "emulsified coating film remover" means a coating film remover that maintains an emulsified state for a long period of time (for example, 24 hours).
Some of the coating film-peeling agents used in the past contain an aromatic alcohol and water, but the coating film-peeling agents cannot be separated into two layers of an organic phase and an aqueous phase, and are uniformly mixed even when left to stand. Such a conventional coating film remover usually contains a surfactant for the purpose of promoting the compatibility between the organic phase and the aqueous phase, or an inorganic alkali compound for the purpose of improving the releasability. A mechanism of peeling off a coating film in the case of using a conventional type of coating film peeling agent will be described with reference to fig. 1. In fig. 1 (a), the circle indicates a base component such as an inorganic base compound. The substance having B in the circle represents benzyl alcohol as an aromatic alcohol. First, benzyl alcohol in the organic phase permeates into the coating film to swell the coating film. Next, the alkali component acts on the coating film whose adhesion to the base material (jig) is reduced by the swelling, and the hydrolysis of the coating film is promoted. The hydrolyzed coating film becomes fine pieces and is suspended in the coating film remover, and the peeling is completed (fig. 1 (B)). In the above mechanism, in order to promote hydrolysis of the coating film by the alkali component, the coating film needs to be peeled at a temperature of 70 ℃.
On the other hand, the coating film remover of the present embodiment is different from the conventional coating film removers in that it separates into at least two layers including a first layer composed of an organic phase and a second layer composed of an aqueous phase when left standing at a temperature at which the coating film is removed. Hereinafter, a mechanism of peeling off a coating film in the case of using the coating film peeling agent of the present embodiment will be described with reference to fig. 2. The following mechanism is a mechanism that the inventors have presumed. In fig. 2 (a), the substance with W indicated in the circle represents water. The substance having B in the circle represents benzyl alcohol as an aromatic alcohol. First, benzyl alcohol in the organic phase permeates into the coating film to swell the coating film. Then, the water phase enters between the coating film whose adhesion to the substrate (jig) is reduced by the swelling and the substrate. Then, the coating film is peeled off by electrostatic repulsion between the coating film and the aqueous phase. Since the electrostatic repulsive force does not have temperature dependency, the coating film can be peeled even in a relatively low temperature environment of 50 ℃ or lower. In the case of the above mechanism, the coating film is not broken by hydrolysis (fig. 2 (B)). Therefore, the coating film after peeling can be recovered more easily than the conventional type of coating film peeling agent, and is suitable for repeated use of the coating film peeling agent.
When the coating film remover further contains an aliphatic hydrocarbon having 4 to 12 carbon atoms, the coating film remover can be separated into three layers, namely a first layer composed of the first organic phase, a second layer composed of the aqueous phase and a third layer composed of a second organic phase containing the aliphatic hydrocarbon having 4 to 12 carbon atoms when the coating film remover is left to stand at a temperature for removing the coating film.
In one aspect of the present embodiment, the coating film-peeling agent may be separated into four or more layers when left standing at a temperature at which the coating film is peeled.
In the case where the coating film remover is composed of the first organic phase and the aqueous phase, the aqueous phase forms an upper layer and the first organic phase forms a lower layer when the coating film remover is left to stand. That is, the first organic phase does not come into contact with the atmosphere when the coating film remover is left standing. Therefore, the present inventors considered that the coating film-peeling agent has almost no flammability.
The pH of the coating film remover is preferably 4 to 10, more preferably 5 to 9, and further preferably 6 to 8. By setting the pH in this manner, hydrolysis of the coating film is suppressed, and the coating film remover is suitable for repeated use. Further, when the coating film is peeled off using the coating film peeling agent, the work safety is improved.
Method for producing coating film-releasing agent
The method for producing a coating film remover according to the present embodiment includes: preparing the aromatic alcohol and the water; and a step of adding the aromatic alcohol to the water. Any method may be used for the addition process. Examples of the addition step include: adding the aromatic alcohol into the water in a flask; and adding the above aromatic alcohol to water on an industrial scale in a chemical plant or the like; and the like.
Method for peeling off coating film
The method for peeling a coating film of the present embodiment is a method for peeling a coating film provided on a surface of a substrate, and includes bringing the coating film peeling agent into contact with the coating film.
The method for bringing the coating film-releasing agent into contact with the coating film is not particularly limited. In this method, for example, there are listed: the contact is made by a method such as dipping, coating, or spraying by spraying or showering, in the atmosphere, under reduced pressure or increased pressure at normal temperature or under heating. When the coating film releasing agent is brought into contact with the coating film by immersion, ultrasonic treatment, bubbling treatment, shaking, or the like may be performed as necessary. In this method, it is preferable that the substrate having the coating film is immersed in a peeling agent tank into which the heated coating film peeling agent is charged to peel the coating film. In this case, it is preferable that the coating film remover is stirred to form a state in which the aqueous phase and the organic phase are uniformly dispersed. The time for immersion is preferably 1 minute to 60 minutes.
In the method for peeling off a coating film according to the present embodiment, the temperature of the peeling agent is preferably 20 to 120 ℃, more preferably 30 to 80 ℃, and still more preferably 40 to 70 ℃.
Then, the release agent may be removed from the base material from which the coating film has been peeled off by ordinary washing and drying. For example, the substrate from which the coating film is peeled off may be cleaned with water, acetone, isopropyl alcohol, or the like, and then dried at room temperature.
The coating film remover of the present embodiment can be suitably used for removing a coating film from a coated article of an automobile part, a bicycle part, a precision equipment, and an exterior part of an electronic part, in addition to the coating jig described above.
The present embodiment has been described above. According to the present embodiment, a coating film-peeling agent and a coating film-peeling method which have excellent peeling properties and are suitable for recycling can be provided.
[ examples ]
The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.
Materials (raw materials)
Hereinafter, names and the like of compounds as raw materials used in the present example are shown.
Benzyl alcohol: trade name of benzyl alcohol manufactured by Tokyo Kasei Kogyo
Isopropyl benzene: product name Cumene manufactured by Mitsubishi chemical corporation
Ethylene glycol monophenyl ether: manufactured by Nippon emulsifier Co., Ltd., trade name PhG
Ethylene glycol mono 2-ethylhexyl ether: trade name EHG manufactured by Nippon emulsifier Co., Ltd
Decane: JXTG energy Co., Ltd, the trade name of Cactus Normal Paraffin N-10
Decahydronaphthalene: the trade name of Decahydronaphthalene manufactured by Nissian iron-god chemical Co., Ltd
N-methyl-2-pyrrolidone (NMP): trade name of NMP manufactured by Mitsubishi chemical corporation
Propylene glycol: commercial propylene glycol manufactured by ADEKA K.K.
Cellulose derivatives: trade name of METOLOSE 60 SH-40, manufactured by shin-Etsu chemical industries, Ltd
Anionic surfactant: sodium alkyldiphenylether disulfonate 50% aqueous solution, PELEXSS-H, manufactured by Kao corporation
Diethylene glycol monoethyl ether: product name Seahosol DG manufactured by Nippon catalyst K.K
Sodium gluconate: trade name of sodium gluconate manufactured by lion king corporation
Caustic potash: trade name of caustic Potassium in the form of flake manufactured by Toyo Synthesis K.K
Pseudocumene: maruzen (available from petrochemical Co., Ltd.) under the trade name of 1, 2, 4-trimethylbenzene
Heptane: wanshan petrochemical Co., Ltd., trade name of n-heptane
Hexane: wanshan petrochemical Co., Ltd., trade name of n-hexane
Isododecane: marukasol R, product name of Marukasol R, manufactured by PELLE petrochemical Co
Experiment 1: comparison of Release Properties of coating film Release agent comprising various organic solvents and Water
< preparation of coating film Release agent >
First, coating film strippers for sample Nos. 1-1 to 1-7 were prepared based on the compounding compositions shown in Table 1. The coating film-peeling agents of samples No. 1-1 to No. 1-6 were allowed to stand at room temperature (25 ℃ C.) and at a temperature (50 ℃ C.) at which the coating film was peeled, and were separated into two layers, an aqueous phase and an organic phase.
< evaluation of releasability of coating film >
(preparation of test piece)
A test piece for evaluation of peelability was produced by the following procedure. Specifically, a cold-rolled steel sheet (70 mm × 50mm in size (t 0.8mm), trade name of which is cold-rolled steel product, manufactured by Standard Test Piece, ltd.) was prepared. Subsequently, the prepared cold-rolled steel sheet was degreased, and then a black paint (product name, POWERNICS 150, manufactured by Nippon paint Co., Ltd.) was applied to the surface of the cold-rolled steel sheet by cationic electrodeposition. Then, the black paint was dried to obtain a test piece having a black coating film.
(evaluation test of peelability)
The coating film strippers of sample Nos. 1-1 to 1-7 were evaluated for strippability according to the following procedures. First, 400ml of the above coating film-releasing agent was put into a beaker (500ml), and heated to 50 ℃. Next, the heated coating film remover is stirred to disperse the aqueous phase and the organic phase. While maintaining the dispersed state, the test piece was immersed in the coating film-releasing agent. After a predetermined time has elapsed from the immersion of the test piece in the release agent, the test piece is taken out, washed with water, and the state of peeling of the coating film is visually observed. The evaluation was made according to the following criteria based on the immersion time until the coating film was completely peeled off. The evaluation results are shown in table 1. In table 1, the portion indicated by "-" indicates that the corresponding component was not added. In Table 1, sample No. 1-1 and sample No. 1-2 correspond to examples. Sample Nos. 1-3 to 1-5 correspond to comparative examples. Sample Nos. 1 to 6 and sample Nos. 1 to 7 correspond to the reference examples.
Reference of evaluation grade
And (4) S grade: 1.5 minutes or less
Grade A: more than 1.5 minutes and 2 minutes or less
Grade B: more than 2 minutes and not more than 2.5 minutes
Grade C: more than 2.5 minutes and less than 3.5 minutes
Grade D: more than 3.5 minutes and less than 5 minutes
Grade E: more than 5 minutes and 10 minutes or less
Grade F: over 10 minutes
[ Table 1]
From the results shown in Table 1, it is clear that the coating film-peeling agents (sample Nos. 1-1 and 1-2) comprising an aromatic alcohol (benzyl alcohol or phenethyl alcohol) and water exhibit A class or B class. On the other hand, the coating film-peeling agents of sample Nos. 1-3 to 1-5 using compounds other than aromatic alcohols as organic solvents were rated F. The coating film-releasing agent of sample No. 1-1 had a releasing property comparable to that of the coating film-releasing agent (sample No. 1-7) comprising an organic solvent which has been conventionally used.
Experiment 2: correlation between blending ratio of aromatic alcohol and water and releasability
Coating film strippers (sample No. 2-1 to sample No. 2-11) were produced with the blend ratio of aromatic alcohol and water changed, and the strippability was evaluated in the same manner as in experiment 1. Benzyl alcohol was used as the aromatic alcohol. The results are shown in table 2 and fig. 3.
[ Table 2]
From the results shown in table 2 and fig. 3, it is understood that the coating film releasing agent exhibits good releasability when the mixing ratio of water (water concentration) is in the range of 10 to 94% by mass (particularly, in the range of 30 to 80% by mass) with respect to the total amount of the coating film releasing agent.
A comparative experiment using NMP instead of benzyl alcohol was also performed. That is, coating film-peeling agents (sample No. 2-12 to sample No. 2-18) were produced with the mixing ratio of the nitrogen-containing compound and water changed, and the peeling property was evaluated by the same method as in experiment 1. NMP was used as the nitrogen-containing compound. The results are shown in table 3 and fig. 3.
[ Table 3]
NMP N-methyl-2-pyrrolidone
As is clear from the results of table 3 and fig. 3, the coating film remover composed of the nitrogen-containing compound and water has a reduced peelability as the blending ratio of NMP decreases (that is, as the water concentration increases). It can be considered that: since NMP has high affinity for water, if the mixing ratio of water is increased, NMP is inhibited from permeating into the coating film, and the peelability is lowered.
Experiment 3: correlation between state of coating film releasing agent and releasability
The coating film-releasing agent of the present example was allowed to stand at room temperature (25 ℃ C.) and at a temperature (50 ℃ C.) at which the coating film was released, and was separated into two layers of an organic phase and an aqueous phase (for example, sample No. 3-1 in FIG. 5). On the other hand, the conventionally used coating film-peeling agents cannot be separated into two layers of an organic phase and an aqueous phase even when left to stand at room temperature and at a temperature at which the coating film is peeled, and are in a uniform state or an emulsified state (for example, sample nos. 3 to 12 in fig. 5). Therefore, the correlation between the state of such a coating film-releasing agent and the releasability has been studied. Specifically, first, coating film strippers for sample No. 3-1 and sample Nos. 3-11 to 3-13 were prepared based on the compounding compositions shown in Table 4. Next, the releasability of the coating film-releasing agent of sample No. 3-1 and sample Nos. 3-11 to 3-13 was evaluated in the same manner as in experiment 1. The results are shown in Table 4. In Table 4, the portion indicated by "-" indicates that the corresponding component was not added. In Table 4, sample No. 3-1 corresponds to the example. Sample Nos. 3-11 to 3-13 correspond to comparative examples.
[ Table 4]
From the results in Table 4, it is understood that the coating film-peeling agents (sample Nos. 3 to 11 and 3 to 13) in which the organic phase and the aqueous phase are in a uniform state when they are left to stand and the coating film-peeling agents (sample Nos. 3 to 12) in which the organic phase and the aqueous phase are emulsified when they are left to stand are rated C or F in the evaluation of the peeling property at 50 ℃. On the other hand, the coating film releasing agent (sample No. 3-1) in which the organic phase and the aqueous phase separated into two layers upon standing as an example was rated A in the evaluation of the releasability at 50 ℃. From the above results, it is understood that the releasability is improved by separating the organic phase and the aqueous phase constituting the coating film-releasing agent into two layers. The following teaching is given: the coating film releasing agent releases the coating film by the following mechanism (see fig. 2 (a)). That is, firstly, benzyl alcohol in the organic phase permeates into the coating film to swell the coating film. Then, the water phase enters between the coating film whose adhesion to the substrate is reduced by swelling and the substrate. Then, the coating film is peeled off by electrostatic repulsion between the coating film and the aqueous phase.
Experiment 4: correlation between the State of coating Release agent and Release Property in Long-term use
Using coating film-releasing agents of sample No. 3-1 and sample Nos. 3-11 to 3-13 having the compounding compositions shown in Table 4, the releasability of these coating film-releasing agents was evaluated for a long period of time. Specifically, the procedure was as follows. First, 10g (5%), 20g (10%), and 40g (20%) of a cured coating film derived from an epoxy resin coating material was added to 200g of each coating film releasing agent, and three samples having different coating material solid content concentrations were prepared. Next, each sample was heated at 90 ℃ for 24 hours. The heated samples were used as a coating film releasing agent, and the releasability was evaluated in the same manner as in experiment 1.
The results are shown in FIG. 4. The horizontal axis represents the content ratio (coating solid content concentration) of the coating solid content (coating film) in the coating film remover before the peeling treatment. The inventors believe that: the coating film-releasing agent having a high content of the solid content of the coating material can be used as a mold for repeatedly performing a releasing treatment for a long period of time.
From the results shown in FIG. 4, it is understood that the coating film remover of sample No. 3-1 as an example maintained the releasability at A level even when the solid content of the coating material was increased. On the other hand, it is found that the coating film release agents of sample Nos. 3-11 and 3-12, which are comparative examples, have a reduced release property from the C-grade to the E-grade or F-grade as the solid content of the coating material increases. The coating film-releasing agents of sample Nos. 3 to 13 as comparative examples were kept at the F-rating from the beginning of the experiment. From the above results, the following is suggested: the coating film-releasing agents of the examples maintained high releasability without causing a decrease in releasability even after long-term use. Namely, the following is suggested: the coating film-peeling agents of the examples were suitable for repeating the peeling treatment.
Experiment 5: study on Effect of improving releasability by addition of other organic solvent
The effect of improving the release properties by adding another organic solvent to a coating film remover comprising an aromatic alcohol (benzyl alcohol or ethylene glycol monobenzyl ether) and water was investigated. First, coating film strippers for sample Nos. 5-1 to 5-13, 5-20 and 5-21 were prepared based on the compounding compositions shown in Table 5. Next, the releasability of the coating film-releasing agents of samples Nos. 5-1 to 5-13, 5-20 and 5-21 was evaluated in the same manner as in experiment 1. The results are shown in Table 5-1 and Table 5-2. In table 5, the portion indicated by "-" indicates that the corresponding component was not added. In tables 5-1 and 5-2, the coating film-releasing agents of samples No. 5-1 to 5-13 correspond to examples. The release agents of samples No.5 to 20 correspond to comparative examples. Sample Nos. 5 to 21 correspond to the reference examples.
[ Table 5-1 ]
[ tables 5-2 ]
As is clear from the results in tables 5-1 and 5-2, the releasability was further improved by adding an aliphatic hydrocarbon having a low surface tension to the coating film-releasing agent (tables 5-1 and 5-2, particularly, sample Nos. 5-5 to 5-7).
While the embodiments and examples of the present invention have been described above, it is originally anticipated that the configurations of the embodiments and examples will be appropriately combined.
It should be considered that: the embodiments disclosed herein are exemplary in all respects, and are not intended to be limiting. The scope of the present invention is defined by the claims, not by the embodiments described above, and all modifications within the meaning and scope equivalent to the claims are intended to be included.
Claims (9)
1. A coating film-peeling agent for peeling a coating film provided on a surface of a substrate,
the coating film stripping agent comprises aromatic alcohol shown in the following formula (1) and water,
the content of the water is 10-94% by mass relative to the total amount of the coating film stripping agent,
in the formula (1), L represents divalent hydrocarbon group with 1-6 carbon atoms, R represents hydrogen atom or hydrocarbon group with 1-3 carbon atoms, and-CH contained in the divalent hydrocarbon group2-is optionally substituted by-O-.
2. The coating film-releasing agent according to claim 1,
comprises the following steps: an organic phase containing the aromatic alcohol; and an aqueous phase containing the water,
the coating film-releasing agent separates into at least two layers including a first layer composed of the organic phase and a second layer composed of the aqueous phase when left standing at a temperature at which the coating film is released.
3. The coating film-releasing agent according to claim 1 or 2, wherein,
the total of the content of the aromatic alcohol and the content of the water is 90 to 100 mass% based on the total amount of the coating film peeling agent.
4. The coating film-releasing agent according to claim 1 or 2, wherein,
the content ratio of each of the cellulose derivative, the inorganic alkali compound and the peroxide is more than 0 mass% and 0.01 mass% or less with respect to the total amount of the coating film peeling agent.
5. The coating film-releasing agent according to claim 1 or 2, wherein,
cellulose derivatives, inorganic base compounds and peroxides are not included.
6. The coating film-releasing agent according to claim 1 or 2, wherein,
l represents an alkylene group having 1 to 3 carbon atoms, and R represents a hydrogen atom.
7. The coating film-releasing agent according to claim 1 or 2, wherein,
the aromatic alcohol includes at least one compound selected from the group consisting of benzyl alcohol, 4-isopropylbenzyl alcohol, 1-phenylethanol, phenethyl alcohol, γ -phenylpropyl alcohol, α -dimethylphenylethanol, 1-phenyl-1-propanol, cinnamyl alcohol, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, and ethylene glycol monobenzyl ether.
8. The coating film-releasing agent according to claim 1 or 2, wherein,
also contains aliphatic hydrocarbon with 4-12 carbon atoms.
9. A method for peeling off a coating film provided on the surface of a substrate,
the method for peeling off the coating film comprises the following steps: the coating film-releasing agent according to claim 1 or 2 is brought into contact with the coating film.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4619706A (en) * | 1985-02-28 | 1986-10-28 | Texo Corporation | Method for stripping organic coatings from substrates |
| CN1234061A (en) * | 1996-10-22 | 1999-11-03 | 布伦特国际公司 | Compositions and method for removing paint from substrate |
| WO2018179925A1 (en) * | 2017-03-28 | 2018-10-04 | 株式会社ネオス | Coating film stripping composition and method for stripping coating film |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6198776A (en) * | 1984-10-19 | 1986-05-17 | Toagosei Chem Ind Co Ltd | Stripping agent composition |
| JPH09235497A (en) * | 1996-03-01 | 1997-09-09 | Ipposha Oil Ind Co Ltd | Water-base coating-film release agent and peeling method |
| FR2756837B1 (en) * | 1996-12-06 | 1999-01-15 | Atochem Elf Sa | STRIPPING COMPOSITION FOR PAINTS, VARNISHES OR LACQUERS |
| JP4388748B2 (en) | 2003-02-20 | 2009-12-24 | 株式会社ネオス | Water-based paint remover |
| SE528010C2 (en) | 2004-12-30 | 2006-08-01 | Stripp Chemicals Ab | Means for removing paint, varnish glue, rubber, plastic or the like from objects and use of said agents |
| JP5152816B2 (en) | 2006-02-24 | 2013-02-27 | 化研テック株式会社 | Cleaning method |
| JP4755659B2 (en) | 2008-01-31 | 2011-08-24 | 磯部塗装株式会社 | Substrate adjustment method |
| JP2016069633A (en) | 2014-09-30 | 2016-05-09 | 株式会社ネオス | Aqueous primer composition for coating material peeling and coating material peeling method |
| JP6193425B2 (en) | 2016-03-04 | 2017-09-06 | 株式会社トウペ | Water-based paint remover |
| JP7172771B2 (en) | 2019-03-18 | 2022-11-16 | 荒川化学工業株式会社 | Undiluted solution for cleaning composition, and cleaning composition containing said undiluted solution for cleaning composition |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4619706A (en) * | 1985-02-28 | 1986-10-28 | Texo Corporation | Method for stripping organic coatings from substrates |
| CN1234061A (en) * | 1996-10-22 | 1999-11-03 | 布伦特国际公司 | Compositions and method for removing paint from substrate |
| WO2018179925A1 (en) * | 2017-03-28 | 2018-10-04 | 株式会社ネオス | Coating film stripping composition and method for stripping coating film |
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| JP2020176220A (en) | 2020-10-29 |
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