JP2017095596A - Two agent type coating release agent composition and coated film releasing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-chlorine-based coated film release composition capable of achieving detachability even with large coating articles or operations in the outdoors at low temperature without needs for a large scale heating device such as a heating tank and a heater.SOLUTION: There is provided a two agent type release agent composition consisting of an A agent and a B agent, wherein the A agent contains a water soluble coated film release agent, the B agent contains a hydration heating agent, and using heat generation effect during mixing is used. There is provided a two agent type release agent composition, wherein the hydration heating agent contains powdery calcium oxide and powdery aluminum at CaO:Al=60:40 to 90:10 by mass ratio and viscosity of the A agent is 1000 to 100000 cP at 25°C.SELECTED DRAWING: None

Description

The present invention relates to a coating film peeling agent composition and a coating film peeling method for a coating film that is difficult to promote peeling by heating in a coating film peeling process for coating materials, resins, rubbers and other coating members in general. .
Examples of the coating object that is difficult to promote peeling by heating according to the present invention include a painted object having a large coating film peeling area such as a steel road bridge, a building, a bullet train, and an aircraft.

  As the release agent used in the coating film removal method, a chlorine-based coating film release agent comprising various solvents mainly composed of a chlorine-based solvent and an acid or alkali composition has been used so far. However, the use of chlorinated solvents is restricted in order to prevent the effects on the human body, the occurrence of pollution, and the deterioration of the work environment. At present, chlorine-based release agents using various solvents that do not use chlorine-based solvents have been developed. However, non-chlorine release agents have a markedly reduced release performance at low or normal temperatures compared to warming (60 ° C. to 90 ° C.). In actual use, the introduction of the heating tank is costly and may be difficult to introduce due to management. In addition, large painted objects such as steel road bridges, buildings, bullet trains, and aircraft are difficult to handle with equipment such as heating tanks and heaters.

  A method of using a chlorine-based solvent such as methylene chloride (Patent Document 1), N-methylpyrrolidone (Patent Document 2), an ethylene glycol ether solvent, acetone, or an alcohol solvent as a coating film release agent is disclosed. Yes. Many chlorinated solvents have a low boiling point and are not preferable from the viewpoint of environmental pollution and occupational health and safety due to diffusion into the air due to volatilization. Similarly, N-methylpyrrolidone is also registered on the REACH authorization list. Also disclosed is a paint remover composition comprising an aqueous solution containing two or more compounds selected from glycol ethers, glycols, aromatic alcohols and organic acids, and an inorganic acid such as formic acid (patent) Reference 3). However, this paint remover composition has problems such as corrosion of the substrate itself on which the coating film is formed.

Japanese Patent Laid-Open No. 5-1771076 JP-A-5-279607 Japanese Patent Laid-Open No. 11-21482

The conventional techniques have the following problems.
(1) Methylene chloride is a chlorinated solvent that is easy to accumulate in the environment and has a large impact on the environment. In line with the revision of the Regulation for the Prevention of Specific Chemical Substances Disorders (Specialized Rules) on November 1, 2014, working environment measurements (preserved for 30 years) and specialized health examinations (preserved for 30 years) for the use of release agents containing methylene chloride ) Is required, making actual use difficult. Since all of the release agents containing methylene chloride currently on the market are solvent-based release agents, it has been desired to develop an environmentally-friendly aqueous release agent.
(2) Many paints on steel road bridges that have to be repainted contain lead and PCB (polychlorinated biphenyl) as harmful substances. The implementation of blasting is limited (“Preventing workers' health problems in peeling and scraping of paint containing lead and other harmful substances”). Therefore, there has been a demand for a chemical treatment method that is free from noise and free from powder contamination.
(3) Since the non-chlorine-based coating film release agent remarkably deteriorates in a winter environment, it has been desired to develop a release agent that can exhibit the release property even in a low temperature environment.

    In view of the above (1) to (3), the present invention does not require a heating device such as a large heating tank or heater, and exhibits releasability even in the case of a large paint or outdoor work at low temperatures. It is an object of the present invention to provide a non-chlorine coating film release agent composition that can be used.

In response to the above problems, the present inventors have achieved a coating film under low temperature and normal temperature environment by utilizing the exothermic effect during mixing according to the coating film peeling agent composition comprising a water-soluble coating film peeling agent and a hydrothermal exothermic agent. It was found that it can be removed. This invention is completed based on such knowledge, and provides the coating film peeling agent composition and coating film peeling method of the following aspects.
Item 1. A two-part coating film release agent composition consisting of agent A and agent B, where agent A contains a water-soluble coating film release agent and agent B contains a hydrothermal exothermic agent object.
Item 2. Item 2. The two-part coating film release agent composition according to Item 1, wherein the hydrothermal exothermic agent contains powdered calcium oxide and powdered aluminum.
Item 3. Item 3. The two-part coating film release agent composition according to Item 1 or 2, wherein the viscosity of the agent A is 1,000 to 100,000 cP at 25 ° C.
Item 4. Item 2. The two-component paint remover composition according to any one of Items 1 to 3, wherein the agent A contains a thickener.
Item 5. Item 2. The two-part coating film release agent composition according to any one of Items 2 to 4, wherein the powdered calcium oxide and the powdered aluminum are in a mass ratio of CaO: Al = 60: 40 to 90:10. object.
Item 6. Item 6. The two-part coating film release agent composition according to any one of Items 2 to 5, wherein the average particle size of the powdered aluminum is 15 μm to 300 μm.
Item 7. A film remover composition prepared by mixing A agent containing a water-soluble film remover with a viscosity of 1,000 to 100,000 cP at 25 ° C and a B agent containing a hydrothermal exothermic agent is attached to the film. The peeling method of the coating film including the process to make.

  The coating film release agent composition of the present invention self-heats when water in the coating film release agent reacts with the hydrothermal exothermic agent, so that a large coating is not required without a large heating device such as a heating tank or heater. The peelability can be exerted even in the outdoor work at a low temperature. Moreover, since the coating film stripper composition of the present invention is non-chlorine and does not produce harmful gas, safety for field workers can be ensured.

  Below, the detail of this invention is demonstrated in more detail based on embodiment.

Agent A
A agent is comprised from a non-chlorine-type component, and contains a coating-film peeling agent main ingredient, a solubilizer, a thickener, and water.

  As the main agent, a high boiling point solvent can be used, and examples thereof include alcohol solvents, amide solvents, glycol solvents, ketone solvents, ester solvents and the like.

  Specific examples of the alcohol solvent include aromatic alcohols such as benzyl alcohol, phenethyl alcohol, hydroxybenzyl alcohol, and hydroxyphenethyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, propargyl alcohol, and the like. Specific examples of the amide solvent include dimethylformamide and dimethylacetamide. Specific examples of the glycol solvent include alkylene glycol phenyl ethers such as ethylene glycol monophenyl ether. Specific examples of the ketone solvent include γ-butyrolactone, 2-pyrrolidone, N-methyl-2-pyrrolidone, and propylene carbonate. Specific examples of the ester solvent include ethyl acetate and butyl acetate. The main agent is preferably an alcohol solvent or a ketone solvent. In particular, benzyl alcohol can be preferably used.

  The content of the main agent is 30 to 80% by mass, preferably 50 to 70% by mass, when the total amount of Agent A is 100% by mass. If the main component is 30% by mass or less, the peelability is remarkably lowered, and if it is 80% by mass or more, the liquid stability is lowered.

  Examples of the solubilizer include sulfonates, alkanolamines, and ketone compounds. Examples of the sulfonate include sodium p-toluenesulfonate, sodium m-toluenesulfonate, sodium o-toluenesulfonate, sodium dodecylbenzenesulfonate, and the like. Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine. Examples of the ketone compound include γ-butyrolactone, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like. The solubilizer is preferably a sulfonate or a ketone compound, and more preferably sodium p-toluenesulfonate, sodium m-toluenesulfonate, or γ-butyrolactone.

  The content of the solubilizer is 5 to 30% by mass, preferably 10 to 20% by mass, when the total amount of agent A is 100% by mass. If it is 5% by mass or less, water and the main agent cannot be made uniform, and if it is 30% by mass or more, the peelability is lowered and the liquid stability is also lowered.

  As thickeners, gums such as methylcellulose, polyvinyl alcohol and xanthan gum, organic thickeners such as alkylcellulose such as ethylcellulose, hydroxyethylcellulose, propylcellulose, butylcellulose and carboxyethylcellulose, and inorganic thickeners such as silica and diatomaceous earth An agent can be mentioned.

  The content of the thickener is 1 to 10% by mass, preferably 2 to 5% by mass, when the total amount of agent A is 100% by mass.

  Each of the main agent, solubilizer and thickener may be used alone or in combination of two or more.

  The viscosity of the agent A is 1,000 to 100,000 cP at 25 ° C., preferably 2,000 to 50,000 cP, more preferably 5,000 to 20,000 cP. If the viscosity is too low, it will drip when applied to an object to be peeled, causing a drop in peelability and a deterioration in the working environment. On the other hand, if the viscosity is too high, coating becomes difficult and workability is significantly reduced. The viscosity is a value measured with a B-type viscometer. A necessary amount of the thickener is added so that the viscosity of the agent A is in this range.

  The water content is 10 to 40% by mass, preferably 20 to 30% by mass, when the total amount of agent A is 100% by mass. If it is 10% by mass or less, a flash point is generated, which is not preferable. If it is 40% by mass or more, the peelability is lowered and the liquid stability is also deteriorated.

  In addition to the above, the agent A of the present invention is a pH adjuster for making the coating film remover acidic or alkaline (in the case of acid, fatty acid, phosphoric acid, etc., in the case of alkali, caustic soda, caustic potash, etc. are added) , Preservatives, chelating agents and the like may be added as appropriate.

B agent
Agent B contains a hydrothermal exothermic agent and reacts with water to generate heat. Examples of the hydrothermal exothermic agent include powdered calcium oxide, a mixture of powdered calcium oxide and powdered aluminum, and the like.

The reaction of calcium oxide and aluminum with water and the amount of heat generated at that time are shown below.
CaO + H ₂ O = Ca (OH) ₂ + 15.2Kcal ・ ・ ・ (I)
When calorific value is converted per gram, the molecular weight of CaO is 56.08, so 271cal / g
2Al + 3Ca (OH) ₂ = 3CaO ・ Al ₂ O ₃ + 3H ₂ ↑ + 47Kcal ・ ・ ・ (II)
Since the molecular weight of Al is 13, 3615 Kcal / g

Since aluminum alone does not react with water unless the temperature is higher than 100 ° C., a reaction between CaO (quick lime) and H ₂ O (water) is required first. For this reason, Al is used in combination with CaO. A larger amount of heat can be obtained by combining CaO and Al.

In the above reaction, Al (powder aluminum) generates heat due to the reaction of Ca (OH) ₂ (calcium hydroxide) generated by the reaction of CaO (quick lime) and H ₂ O (water). Ca (OH) ₂ (calcium hydroxide) functions as a reaction initiator or a kind of catalyst for reacting Al (powder aluminum) at a temperature of 100 ° C. or lower.

  Commercial calcium oxide / aluminum may be used as the calcium oxide / aluminum, but it can be prepared by mixing commercial products of powdered calcium oxide and powdered aluminum. Powdered calcium oxide can be obtained from Kishida Chemical Co., Ltd., and powdered aluminum can be obtained from Minalco Co., Ltd., Daiwa Metal Powder Industry Co., Ltd., etc.

  Any particle size can be used for the powdered calcium oxide and the powdered aluminum, but the average particle size is preferably 15 μm to 300 μm. Above this particle size, the area in contact with water decreases, so the hydration reaction when water is added is delayed and heat generation is delayed.

  Powdered calcium oxide and powdered aluminum are preferably used in a mass ratio of CaO: Al = 60: 40 to 90:10, preferably 75:25 to 85:15.

  In addition to the main exothermic agent, B agent contains carbonates such as sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, sodium chloride, magnesium chloride, magnesium sulfate, calcium sulfate, sodium sulfite, sodium phosphate, etc. It may be contained as a heat generation aid.

    As the B agent, the mixed exothermic agent may be used as it is (in the form of powder), but a sheet-like molded body containing the B agent can also be produced and used.

  Agent B should be stored in a container that can be sealed except during use, avoiding storage under conditions that react with water such as in a humid atmosphere.

Two-part coating film release agent composition and coating film peeling method The two-part coating film release agent composition of the present invention is used by mixing or contacting agent A and agent B immediately before use. The release agent composition itself generates heat due to the reaction between the water contained in agent A and the calcium oxide and aluminum contained in agent B, and it is possible to remove the coating film under heated conditions without depending on the equipment. Become.

  As a method for preparing the coating film release agent composition of the present invention, an agent A (water-soluble paint remover) and a powder B agent (hydrothermal exothermic agent) are mixed and stirred to be uniform. Either agent A or agent B may be added first, but agent A and agent B are preferred.

The ratio of the A agent and the B agent may be appropriately adjusted depending on the water content in the A agent, the ratio of powdered calcium oxide in the B agent, the ratio of the powdered aluminum, etc. Is used in the range of 60:40 to 90:10. The weight ratio of H ₂ O water and B contained in the A agent (mixture of CaO and Al): B agent 45: 55 to 70: it is preferably adjusted so that 30. When the amount of the B agent is too large, the coating film release agent composition does not sufficiently generate heat, and application becomes difficult.

The coating film release agent composition of the present invention is used by adhering to the coating material by applying or spraying the coating material to the coating material after mixing the A agent and the B agent. Then, after leaving it for a certain period of time, it is removed by a scraper or wiping to recover the coating film release agent composition and the coating film waste.
According to the coating film release agent composition of the present invention, the coating film can be recovered without scattering only by lightly wiping the surface of the coating film that has become wet by coating.

  After mixing the A agent and the B agent, the temperature of the coating film release agent composition of the present invention starts to rise. When the coating film release agent composition of the present invention has a high viscosity, it is easy to control the temperature. However, it may be applied to a coated material immediately after mixing or before the peak of heat generation.

  When the agent B is a sheet-like molded article, the agent A is applied to the surface of the coated film, and then the agent B is pasted. Sheet B agent absorbs water contained in A agent and begins to generate heat. After standing for a certain time, the sheet is collected.

The release agent composition of the present invention is used by applying about 100 to 1000 g / m ² to the coated product. The treatment time is usually 1 to 24 hours. What is necessary is just to adjust suitably the application quantity and processing time of a release agent composition by the kind of coating material, a film thickness, etc. FIG. Since the release agent composition of the present invention self-heats, it is not necessary to heat using a heating device or the like.

  The coated objects to which the coating film release agent composition of the present invention is applied are generally automobile coating, factory floor coating, and a coating jig. Specifically, the types of paint are epoxy resin paint, urethane paint, lacquer paint, and phthalic acid paint. Examples of the material of the base material on the bottom surface of the paint include steel materials, stainless steel materials, cast iron, copper, and copper alloys. In the present invention, the target paint can be peeled off without affecting the base material on the bottom surface of the paint.

  The present invention is effective when it is difficult to introduce a heating tank in practical use as follows. For example, if the heating tank cannot be installed due to cost, or if it cannot be placed in the heating tank due to a large paint, the coating peeling after heating peeling will not be heated again. In the case of carrying out, there are cases where it is difficult to deal with equipment such as a steel film bridge, a building, a bullet train, an aircraft, etc., and the use of a hot bath or heating with a heater.

  Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples.

[Exothermic test of release agent composition]
Water A, benzyl alcohol (main agent), sodium p-toluenesulfonate (solubilizer), and methylcellulose (thickener) were mixed to prepare agent A (P1, P2). The composition is shown in Table 1. The temperature of the A agent after the adjustment was 20 ° C to 25 ° C.
CaO [Kishida Chemical Co., Ltd. average particle size 75 μm; purity> 95%] and Al [Minalco Co., Ltd. # 350F (average particle size 15 μm) or # 300A (average particle size 25 μm) or # 260S (average particle size 45 μm)] Were mixed to prepare B agent. The composition of agent B is shown in Table 2.
A release agent composition was prepared by adding B agent to A agent and stirring at room temperature. After mixing, the maximum exothermic temperature of the release agent composition, its arrival time, and the time until the temperature dropped to 30 ° C. were measured. The results are shown in Table 2.

[Paint peeling test]
150 g of the release agent composition was prepared in a beaker at the ratio shown in Table 2.
The following 4 types of test pieces were immersed in the release agent composition immediately after mixing, and after a predetermined time passed, the surface of the test piece was lightly rubbed with a commercially available cotton swab and tested to see if the coating film could be removed by applying physical force . The evaluation criteria were as follows.
A: The coating film could be easily removed B: The coating film could be removed ×: The coating film could not be removed

Coating 1 (paints for painting automotive parts) :
Cold rolled steel sheet (SPCC) in which paint for automobile parts coating (white paint OP-30-P made by Nippon Paint Co., Ltd.) is applied at a baking temperature of 140 ° C (30 minutes) and the number of times of coating (film thickness 50 µm) -SD) A flat plate (70 mm x 50 mm x 0.8 mm) was used as a test piece. After immersing the test piece in the release agent composition, the test piece was allowed to stand at room temperature for 30 minutes to confirm whether the coating film could be removed.
Painted object 2 (Ultra-thick film epoxy resin primer for building painting) :
The main material is epoxy resin (Eponic H), the curing agent is a modified aliphatic polyamine, and the coating temperature is 30 ° C (24 hours). A (SSPC-Pt3) flat plate (70 mm × 50 mm × 0.8 mm) was used as a test piece. After immersing the test piece in the release agent composition, the test piece was allowed to stand at room temperature for 10 hours to confirm whether the coating film could be removed.
Painted material 3 (Electrodeposition paint for painting automotive parts) :
Phosphoric acid coated with a cationic electrodeposition paint (Sucsade 80V DuPont Shinto Automotive Systems Co., Ltd.) with a baking temperature of 165 ° C (20 minutes) and a single coating (film thickness 15-20μm) A zinc-coated cold-rolled steel plate (SPCC-SD) flat plate (70 mm × 50 mm × 0.8 mm) was used as a test piece. After immersing the test piece in the release agent composition, the test piece was allowed to stand at room temperature for 5 hours to confirm whether the coating film could be removed.
Painted material 4 (undercoating for paint for bridges) :
Pieces of the red lead paint applied as the foundation of the paint for bridges (on-site collected product, about 5 mm x 5 mm x 2 mm) were used as test pieces. After immersing the test piece in the release agent composition, the test piece was allowed to stand at room temperature for 2 hours to confirm whether the coating film was dissolved.

From Table 2, it can be seen that the release agent composition of the present invention has excellent release properties for various coating films due to the heat generation effect. When only agent A was used or when agent B was only Al (powder aluminum), the heat generation was small and the coating film did not peel off. In addition, when the viscosity of the agent A was high, the temperature increase after heat generation was milder than that when the viscosity was low, and it was difficult to decrease after the increase, so that the release agent composition was easily applied.

Claims (7)

 A two-part coating film release agent composition consisting of agent A and agent B, where agent A contains a water-soluble coating film release agent and agent B contains a hydrothermal exothermic agent object.   The two-part coating film release agent composition according to claim 1, wherein the hydrothermal exothermic agent contains powdered calcium oxide and powdered aluminum.   The two-part coating film release agent composition according to claim 1 or 2, wherein the viscosity of the agent A is 1,000 to 100,000 cP at 25 ° C. The two-component paint remover composition according to any one of claims 1 to 3, wherein the agent A contains a thickener.   The two-part coating film release agent according to any one of claims 2 to 4, wherein the powdered calcium oxide and the powdered aluminum are in a mass ratio of CaO: Al = 60: 40 to 90:10. Composition.   The two-part coating film release agent composition according to any one of claims 2 to 5, wherein the average particle size of the powdered aluminum is 15 µm to 300 µm.   A film remover composition prepared by mixing A agent containing a water-soluble film remover with a viscosity of 1,000 to 100,000 cP at 25 ° C and a B agent containing a hydrothermal exothermic agent is attached to the film. The peeling method of the coating film including the process to make.