Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/06—Polyurethanes from polyesters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3203—Polyhydroxy compounds
  • C08G18/3206—Polyhydroxy compounds aliphatic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/4266—Polycondensates having carboxylic or carbonic ester groups in the main chain prepared from hydroxycarboxylic acids and/or lactones
  • C08G18/4269—Lactones
  • C08G18/4277—Caprolactone and/or substituted caprolactone
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/44—Polycarbonates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
  • C08G18/6633—Compounds of group C08G18/42
  • C08G18/6637—Compounds of group C08G18/42 with compounds of group C08G18/32 or polyamines of C08G18/38
  • C08G18/664—Compounds of group C08G18/42 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
  • C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
  • C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
  • C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2150/00—Compositions for coatings
  • C08G2150/90—Compositions for anticorrosive coatings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2203/00—Foams characterized by the expanding agent
  • C08J2203/22—Expandable microspheres, e.g. Expancel®
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
  • C08J2375/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/32—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof from compositions containing microballoons, e.g. syntactic foams
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/14—Polymer mixtures characterised by other features containing polymeric additives characterised by shape
  • C08L2205/18—Spheres
  • C08L2205/20—Hollow spheres

Definitions

• This disclosure relates to coating materials, coating layers, and springs.
• Patent Document 1 discloses a method for forming a coating on a coil spring, which is characterized in that "at least a portion of the axial direction of a coil spring that has been preheated to a predetermined surface temperature is rolled in a trough-shaped container that contains thermoplastic resin powder having a melting point of 250°C or less, and the resin powder that has adhered to the spring wire of the coil spring is heated and melted, and then solidified.”
• Patent Document 2 also discloses a "highly durable spring having a single coating film with a thickness of 450 ⁇ m or less, the coating film containing epoxy resin, phenolic resin, and zinc.” Patent Document 2 also discloses that "the coating film is a cured product of an epoxy resin-based powder paint containing epoxy resin, phenolic resin, and zinc.”
• Patent Document 3 discloses "a chip-resistant powder topcoat on a steel substrate having thereon a corrosion-resistant powder coating basecoat, the chip-resistant powder topcoat comprising a cured or fused product of a coating powder of one or more resin components of one or more toughened epoxy resins, 0.1 to 5 parts per hundred parts of resin (phr) of one or more waxes, and optionally up to 200 phr of one or more extenders.”
• Patent document 4 also discloses a coil spring used in vehicle suspension, characterized in that the coating is made thicker in a portion of the spring that satisfies at least one of the following conditions: the stress during use is higher than in other portions, and the probability of the coating being damaged by flying stones is higher than in other portions.
• the hardened layer (coating layer) that remains on the spring must have durability (tear strength).
• the objective of this disclosure is to provide a coating material capable of forming a coating layer with excellent tear strength, a coating layer with excellent tear strength, and a spring that utilizes the same.
• ⁇ 1> A coating material in which the air bubble rate of the cured layer after curing is 0 to 50%.
• ⁇ 2> The coating material according to ⁇ 1>, wherein the cured layer has an air bubble ratio of 5 to 50% after curing.
• ⁇ 3> The coating material according to ⁇ 1> or ⁇ 2>, wherein the average diameter of bubbles in the cured layer after curing is 30 to 2000 ⁇ m.
• ⁇ 4> ⁇ 4>
• ⁇ 9> The coating layer according to ⁇ 7> or ⁇ 8>, wherein the average diameter of the bubbles is 30 to 2000 ⁇ m.
• the coating layer according to any one of ⁇ 7> to ⁇ 10> which comprises a cured material layer having a urethane bond.
• the coating layer according to any one of ⁇ 7> to ⁇ 11> which is used for a spring.
• the present disclosure provides a coating material capable of forming a coating layer with excellent tear strength, a coating layer with excellent tear strength, and a spring using the same.
• the numerical range indicated using “to” indicates a range that includes the numerical values before and after "to” as the minimum and maximum values, respectively.
• the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in another stepwise manner.
• the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
• each component may contain multiple substances corresponding to the component.
• the amount of each component is mentioned in this specification, if there are multiple substances corresponding to the component, the total amount of the multiple substances is meant unless otherwise specified.
• the coating material according to the present embodiment has a bubble rate of 0 to 50% in the cured layer (i.e., coating layer) after curing. Since the amount of bubbles that cause a decrease in strength is as small as 0 to 50% in the cured layer of the coating material according to the present embodiment, a coating layer with excellent tear strength can be formed. Furthermore, the coating layer according to this embodiment has excellent tear strength because it has only 0 to 50% of air bubbles, which are the starting points for reducing strength.
• the coating material and coating layer according to this embodiment will be described in detail below.
• the cured layer of the coating material according to this embodiment after curing is also referred to as a "coating layer.”
• the air bubble content of the cured layer (coating layer) after curing is 0 to 50%, more preferably 5 to 50%, and further preferably 10 to 50%.
• the air bubble ratio of the cured layer (coating layer) after curing is adjusted to 5 to 50% (preferably 10 to 50%) to 5 to 50% (preferably 10 to 50%).
• the coating layer has a void ratio of 5 to 50%, the bubbles in the coating layer can reflect and attenuate the sound generated upon contact, lowering the sound pressure of the generated sound, thereby suppressing the generation of abnormal noise.
• the tear strength decreases, and the durability of the coating layer decreases.
• the air bubble ratio exceeds 50%, the tear strength tends to become 45 N/mm or less, and the durability of the coating layer decreases, so the upper limit of the air bubble ratio is set to 50%.
• the air void content of the cured layer (coating layer) after curing can be adjusted to 5% or more by, for example, the following methods (1) to (3).
• (1) A method of incorporating a foaming agent into the coating material that expands when heated.
• (2) A method in which the raw materials are premixed to dissolve gas into the coating material, and then these gases act as nuclei for the growth of bubbles when the coating layer is formed.
• (3) When the cured layer has urethane bonds, water is added to the coating layer to generate carbon dioxide through a reaction with isocyanate, thereby causing foaming.
• the air bubble rate of the cured layer (coating layer) after curing is measured by the underwater specific gravity method using A&D's "Specific Gravity Measurement Kit AD-1654.”
• the average diameter of air bubbles in the cured layer (coating layer) after curing is preferably 30 to 2000 ⁇ m, more preferably 30 to 1200 ⁇ m, and even more preferably 30 to 700 ⁇ m, from the viewpoints of improving tear strength and suppressing abnormal noise.
• the average diameter of the cured layer (coating layer) is within the above range, it is less likely that the coating layer will have a locally small thickness due to larger bubbles, and a decrease in tear strength is suppressed. In addition, sound vibrations are prevented from being transmitted directly from the surface of the cured layer (coating layer) to the interface with the article, improving the noise suppression effect. In addition, it is less likely that unevenness will occur on the surface of the cured layer (coating layer).
• the average bubble diameter can be adjusted, for example, by the methods shown in (11) to (13) below.
• (11) In the above method (1) of incorporating a foaming agent that expands when heated into the coating material, a foam stabilizer is added to the coating material together with the foaming agent.
• (12) In the method of (2) above, in which the raw materials are premixed to dissolve gas in the coating material, and when the coating layer is formed, the gas is used as a nucleus to grow bubbles, a foam stabilizer is added to the coating material.
• the average bubble diameter in the cured layer (coating layer) after curing is measured as follows. First, the cured layer (coating layer) to be measured is sliced parallel to the thickness direction to obtain a sample. The cut surface of the sample is observed as the observation surface using an optical microscope ("One Shot 3D Shape Measuring Machine Head VR-3100" manufactured by Keyence Corporation). Then, the maximum diameter of any 10 bubbles in the observed image is measured, and the arithmetic mean value of the 10 maximum diameters is taken as the average diameter of the bubbles.
• the tear strength of the cured layer (coating layer) after curing at 25° C. is preferably 45 kN/m or more, and more preferably 60 kN/m or more.
• the tear strength is measured in accordance with the tear test specified in JIS K 7311:1995.
• the tear strength of the cured layer of the coating material according to this embodiment after curing is a value measured under the condition of a thickness of 2 mm.
• the coating material of the present embodiment may be either a thermoplastic resin composition or a composition for forming a thermosetting resin, so long as it can form a cured layer (coating layer) that satisfies the above-mentioned characteristics.
• the thermoplastic resin include acrylic resin, polystyrene resin, polyethylene resin, polypropylene resin, polyamide resin, nylon resin, vinyl chloride resin, polyacetal resin, polycarbonate resin, polyphenylene ether resin, polybutylene terephthalate resin, polyphenylene sulfone resin, polysulfone resin, polyarylate resin, and polyetherimide resin.
• thermosetting resin examples include urethane resin, epoxy resin, cyanate resin, melamine resin, and phenol resin.
• Other examples of the rubber material include natural rubber, butadiene rubber, chloroprene rubber, nitrile butadiene rubber, and styrene butadiene rubber.
• the cured layer after curing is preferably a cured layer having a urethane bond, and specifically, is preferably a urethane resin layer.
• the coating material of the present embodiment is preferably a composition containing (A) a polymer polyol, (B) an isocyanate, and (C) a chain extender, or a composition containing (D) a prepolymer obtained by reacting a polyol with an isocyanate.
• the (A) polymer polyol preferably contains at least one selected from the group consisting of (A1) polycarbonate-based polyols, (A2) polyether-based polyols having a bisphenol structure, (A3) lactone-based polyols, (A4) polyester-based polyols, and (A5) copolymers of polycarbonate-based polyols and lactone-based polyols.
• polycarbonate-based polyol (A1) examples include polyols obtained by reacting glycol with alkylene carbonate, polyols obtained by reacting glycol with diaryl carbonate, and polyols obtained by reacting glycol with dialkyl carbonate.
• alkylene carbonate examples include ethylene carbonate, 1,2-propylene carbonate, and 1,2-butylene carbonate.
• diaryl carbonates include diphenyl carbonate, 4-methyldiphenyl carbonate, 4-ethyldiphenyl carbonate, 4-propyldiphenyl carbonate, 4,4'-dimethyldiphenyl carbonate, 2-tolyl-4-tolyl carbonate, 4,4'-diethyldiphenyl carbonate, 4,4'-dipropyldiphenyl carbonate, phenyltoluyl carbonate, bischlorophenyl carbonate, phenylchlorophenyl carbonate, phenylnaphthyl carbonate, and dinaphthyl carbonate.
• dialkyl carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, di-n-butyl carbonate, diisobutyl carbonate, di-t-butyl carbonate, di-n-amyl carbonate, and diisoamyl carbonate.
• polyether polyols having a bisphenol structure examples include polyether polyols obtained by adding polyethylene oxide and/or polypropylene oxide to a cyclic diol (such as bisphenol A, hydrogenated bisphenol A, bisphenol S, or bisphenol P), a propylene oxide adduct of bisphenol A, an ethylene oxide adduct of bisphenol A, an ethylene oxide adduct of hydrogenated bisphenol A, and a propylene oxide adduct of hydrogenated bisphenol A.
• the polyether polyol is preferably a propylene oxide adduct of bisphenol A.
• lactone polyol (A3) examples include ring-opening polymers of lactones (such as ⁇ -caprolactone and ⁇ -methyl- ⁇ -valerolactone). Among these, the ring-opening polymer of caprolactone (caprolactone-based polyol) is preferable.
• the polyester polyol (A4) may be a condensation type polyester polyol of a polybasic acid and a polyhydric alcohol other than a lactone polyol.
• the polybasic acid include polyvalent carboxylic acids.
• Specific examples of the polybasic acid include phthalic acid, isophthalic acid, tetrahydrophthalic acid, tetrahydroisophthalic acid, hexahydrophthalic acid, hexahydroterephthalic acid, trimellitic acid, adipic acid, sebacic acid, succinic acid, azelaic acid, fumaric acid, maleic acid, itaconic acid, pyromellitic acid, and acid anhydrides thereof.
• polyhydric alcohols examples include glycols and trihydric or higher polyhydric alcohols.
• glycols include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, hexylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, methylpropanediol, cyclohexanedimethanol, and 3,3-diethyl-1,5-pentanediol.
• trihydric or higher polyhydric alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and dipentaery
• a copolymer of a polycarbonate-based polyol and a lactone-based polyol includes the above-mentioned (A1) polycarbonate-based polyol and the above-mentioned (A3) lactone-based polyol.
• each of the polymer polyols (A) may be used alone or in combination of two or more types.
• the number average molecular weight of the high molecular weight polyol (A) is preferably from 300 to 12,000, and more preferably from 800 to 4,000.
• the number average molecular weight is the molecular weight calculated from the measured value of the hydroxyl value and the number of functional groups according to JIS K 0070.
• the number average molecular weights of other components are also measured in the same manner.
• (B) isocyanate examples include well-known polyisocyanates such as aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, xylene-1,4-diisocyanate, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, and 3,3'-dichloro-4,4'-diphenylmethane diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate, propylene-1,2-diisocyanate, and butylene-1,2-diisocyanate; and alicyclic diisocyanates such as isophorone diisocyanate, 4,4'-dicyclohexy
• chain extender (C) examples include difunctional to tetrafunctional polyols having a molecular weight of 60 to 300.
• Examples of bifunctional polyols include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, pentanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol; alicyclic diols such as cyclohexanediol and hydrogenated xylylene glycol; aromatic diols such as xylylene glycol; and polyether polyols obtained by addition polymerization of alkylene oxides (ethylene oxide, propylene oxide, etc.) to dihydric alcohols.
• the addition polymerization of multiple types of alkylene oxides may be random addition polymerization or block addition polymerization.
• trifunctional polyols include trihydric alcohols having 3 to 10 carbon atoms, such as glycerin and trimethylolpropane.
• trifunctional polyols include polyether polyols obtained by addition polymerization of alkylene oxides (ethylene oxide, propylene oxide, etc.) to trihydric alcohols.
• the addition polymerization of multiple types of alkylene oxides may be random addition polymerization or block addition polymerization.
• tetrafunctional polyols include polyether polyols obtained by addition polymerization of alkylene oxide with ethylenediamine, pentaerythritol, or the like.
• low molecular weight polyols include ester-based polyols obtained by condensing adipic acid and a short chain diol such as ethylene glycol or 1.4-butanediol with a polyfunctional triol such as glycerin.
• the chain extender (C) may be used alone or in combination of two or more kinds. It may be reacted in advance with the polyisocyanate to form a prepolymer.
• preferred chain extenders (C) are ethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, and glycerin, with 1,4-butanediol and 1,6-hexanediol being more preferred.
• the prepolymer is a prepolymer obtained by reacting a polyol with an isocyanate.
• the polyol include the above-mentioned (A) high molecular weight polyol and the above-mentioned (C) low molecular weight polyol as examples of the chain extender.
• the isocyanate includes the above-mentioned (B) isocyanate.
• composition containing the (D) prepolymer may contain, in addition to the (D) prepolymer, at least one selected from the group consisting of (A) high molecular weight polyol, (B) isocyanate, and (C) chain extender.
• the coating material of the present embodiment may contain other components.
• other components include well-known additives such as catalysts, thickeners, antioxidants, colorants, ultraviolet absorbers, inorganic fillers (calcium carbonate, etc.), water, foam stabilizers, and antifoaming agents.
• additives such as catalysts, thickeners, antioxidants, colorants, ultraviolet absorbers, inorganic fillers (calcium carbonate, etc.), water, foam stabilizers, and antifoaming agents.
• the structure of the resin itself can be made highly heat resistant, and crosslinking agents and reinforcing agents (CNT, etc.) can also be added to increase heat resistance.
• CNT crosslinking agents and reinforcing agents
• the equivalent ratio ((A+C)/(B+D)) of the (A) high molecular weight polyol and (C) chain extender to the (B) isocyanate and (D) prepolymer obtained by reacting a polyol with an isocyanate is preferably 0.5 to 1.5, or 0.8 to 1.2.
• the mass ratio (A/C) of the high molecular weight polyol (A) to the chain extender (C) is preferably 1.0 to 35.0, or 1.5 to 10.0.
• the mass ratio (D/C) of the prepolymer obtained by reacting (D) a polyol with an isocyanate to the chain extender (C) is preferably 1.0 to 15.0, or 5.0 to 10.0.
• the coating material of the present embodiment can be suitably used as a coating material for forming a protective layer for articles such as springs, stabilizers, bumpers, and building materials (wall tiles, etc.).
• the article may be a painted article.
• the coating material of the present embodiment may alternatively be a coating material for springs.
• the article of the present embodiment has a cured layer (i.e., a coating layer) of the coating material for springs of the present embodiment on at least a portion of the surface.
• the spring of this embodiment has a hardened layer of the coating material for a spring of this embodiment on at least a part of its surface.
• the spring may be either a coil spring or a leaf spring.
• the embodiment in which the cured layer of the coating material is provided is, for example, as follows. 1) The surface of the coil spring where the spring wires come into contact with each other, for the purpose of preventing abnormal noise caused by contact between the spring wires. 2) The surface of the seat winding part of the coil spring, or part or the entire coil spring, for the purpose of protecting the paint. 3) Part or the entire FRP leaf spring, for the purpose of absorbing shock and preventing fraying.
• the method for applying the coating material of the present embodiment is not particularly limited, and any of a variety of application methods, including dip coating, spray coating, roller coating, brush coating, and flow coater methods, can be used.
• the thickness of the cured layer to be formed is 1 mm or more (particularly, 1 to 2 mm), and therefore there is a concern about the problem of sagging of the coating film. Therefore, it is also preferable to add a thickener to the coating material of this embodiment to increase the viscosity.
• Examples 1 to 15, Comparative Example 1> The components (excluding isocyanate) in the amounts (parts) shown in Table 1, which had been preheated to 50° C., were precisely weighed into a plastic cup and mixed in a planetary centrifugal mixer (ARE-310, manufactured by Thinky Co., Ltd.) at 2000 rpm for 30 seconds. In the case of physically foaming (examples marked “Yes” in the "Pre-mixing” column in the table), the components (excluding isocyanate) in the amounts (number of parts) shown in Table 1 were mixed, and then pre-mixing was performed with a disper at 2000 rpm for 1 minute to dissolve air into the solution.
• ARE-310 planetary centrifugal mixer
• the coating material of each example was applied to an SPCC steel plate having a width of 12.5 mm, a length of 70 mm and a thickness of 3.2 mm, and then cured at 180°C for 10 minutes to form a hardened layer (coating layer) having a thickness of 2 mm to prepare a test specimen.
• the test pieces were then used to carry out the following evaluations.
• bubble rate average bubble diameter
• Tear strength The tear strength of the coating layer at 25° C. was measured according to the method previously described.
• the fatigue durability was evaluated using a fatigue testing machine (linear-torsion type dynamic fatigue testing machine "E10000") manufactured by Instron Corporation. Specifically, the following procedure was performed. A round rod with a diameter of 15 mm was pressed against the test piece so as to sandwich the coating layer, and a load was repeatedly applied under conditions of a minimum load of 10 N and a maximum load of 3000 N, and the number of vibrations until the coating layer broke (hereinafter, the number of breaks) was measured. Then, the test piece was evaluated according to the following criteria. A: The number of breaks exceeds 100,000 times. B: The number of breaks is 10,000 times or more and less than 100,000 times. C: The number of breaks is 1,000 times or more and less than 10,000 times. D: The number of breaks is less than 1,000 times.
• the prepared test piece was suspended by a string and struck from the coating layer side with an impulse hammer to carry out a hammering test, and the sound pressure at a frequency of 5000 Hz was measured. Then, the sound pressure of Example 1 was used as a reference, and the sound pressure difference (dB) between the sound pressure of Example 1 and each example was obtained.
• the equipment used in the hammering test is as follows: Impulse hammer: Ono Sokki "GK-3100" Sound collection microphone: Ono Sokki "LA-5570" FFT (Fast Fourier Transform) analysis equipment: Ono Sokki "DS-3000"
• the coating material of this example is capable of forming a coating layer having excellent tear strength. It is also evident that the coating layers of the examples having a void ratio of 5% or more are able to suppress the generation of abnormal noise.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Paints Or Removers (AREA)
• Laminated Bodies (AREA)

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• 2023
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