Primer composition

Abstract

One embodiment of the present invention relates to a primer composition, a primer coating film, a laminated antifouling coating film, a method for manufacturing a substrate with a primer coating film, and a method for manufacturing a substrate with a laminated antifouling coating film. The primer composition contains an olefin resin (A) and a flat pigment (B) and satisfies any one of the following conditions 1 to 3. Condition 1: The primer composition contains an organic solvent immiscible with water, the average particle diameter of the pigment (B) is 25 μm or more, and the content of the pigment (B) is 17% by mass or more based on 100% by mass of the solid content of the primer composition. Condition 2: The primer composition contains an organic solvent immiscible with water, the average particle diameter of the pigment (B) is less than 25 μm, and the content of the pigment (B) is 42% by mass or more based on 100% by mass of the solid content of the primer composition. Condition 3: The primer composition contains water, the resin (A) is an aqueous resin, and the content of the pigment (B) is 50% by mass or more based on 100% by mass of the solid content of the primer composition.

Description

Technical Field

[0001] One embodiment of the present invention relates to a primer composition, a primer coating film, a laminated antifouling coating film, a method for manufacturing a substrate with a primer coating film, and a method for manufacturing a substrate with a laminated antifouling coating film. Background Art

[0002] Substrates of marine structures, offshore power generation equipment, etc. are usually steel structures, and are used by applying heavy-duty anticorrosive coatings and antifouling coatings because they are installed in environments with severe corrosion and fouling conditions.

[0003] In recent years, it has become more common to use plastic components that are not easily corroded in some of these structures. Such plastic components also need to be coated with an antifouling coating. However, if the antifouling coating is directly applied to the plastic component, since the resulting antifouling coating film has poor adhesion to the component, a primer coating is usually applied to the plastic component, and then an intermediate coating (adhesive coating) is applied, and then the antifouling coating is applied.

[0004] In the case of using the existing primer coating as described above, in order to obtain sufficient adhesion to the plastic substrate, a primer coating film is formed on the substrate by a baking treatment using heating.

[0005] Such a baking treatment not only causes adverse effects such as deformation and shrinkage of the substrate, but also makes the process complicated and the cost high due to carrying out this treatment. Due to these factors, it is necessary to develop a primer coating that can adhere to a plastic substrate without going through this baking treatment.

[0006] As a primer coating that can adhere to a plastic substrate without going through a baking treatment, a primer coating containing chlorine (including chlorides) is known. Most plastic components are incinerated at the end of their service life, and in this incineration disposal, if the component contains a primer coating film containing chlorine, there is a risk of generating harmful gases such as hydrogen chloride gas.

[0007] In addition, as a primer coating that can adhere to a plastic substrate without going through a baking treatment, primer coatings described in Patent Documents 1 and 2 are also known, for example.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: International Publication No. 2018 / 135418

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2019-167389 Summary of the Invention

[0012] Technical Problem to be Solved by the Invention

[0013] However, the adhesion of the primer coating film formed from existing primer coatings such as those described in the above patent documents to a plastic substrate is insufficient, and there is room for improvement in this regard.

[0014] In addition, as described above, after applying the primer coating, an intermediate coating and an antifouling coating are applied. The adhesion between the primer coating film formed from the existing primer coating and the antifouling coating film formed from the antifouling coating is poor. Therefore, in order to improve their adhesion, the intermediate coating is applied, but from the viewpoints of process simplification and economy, etc., it is preferable not to use the intermediate coating.

[0015] However, it is known that when an antifouling coating film is formed on the primer coating film formed from existing primer coatings such as those described in the above patent documents, the adhesion is poor, and peeling easily occurs between the substrate and the primer coating film, or between the primer coating film and the antifouling coating film.

[0016] One embodiment of the present invention provides the following primer composition. This primer composition can form a primer coating film with excellent adhesion to a plastic substrate even without undergoing a baking treatment using heating, and can form a primer coating film that is not easily peeled between the substrate and the primer coating film, and between the primer coating film and the antifouling coating film even when an antifouling coating film (especially a silicone resin-based antifouling coating film) is formed on the primer coating film.

[0017] Technical solutions for solving technical problems

[0018] After repeatedly and deeply studying the methods for solving the above technical problems, it was found that the above technical problems can be solved by a specific composition, and thus the present invention was completed.

[0019] The constitutional examples of the present invention are as follows.

[0020] <1> A primer composition containing an olefin resin (A) and a flat pigment (B), satisfying any one of the following conditions 1 to 3.

[0021] Condition 1: The above primer composition contains an organic solvent (C) that is not miscible with water, the average particle diameter of the above flat pigment (B) is 25 μm or more, and the content of the above flat pigment (B) is 17% by mass or more based on 100% by mass of the solid content of the above primer composition.

[0022] Condition 2: The above primer composition contains an organic solvent (C) that is not miscible with water, the average particle diameter of the above flat pigment (B) is less than 25 μm, and the content of the above flat pigment (B) is 42% by mass or more based on 100% by mass of the solid content of the above primer composition.

[0023] Condition 3: The above primer composition contains water (D), the above olefin resin (A) is an aqueous resin, and the content of the above flat pigment (B) is 50% by mass or more based on 100% by mass of the solid content of the above primer composition.

[0024] <2> The primer composition according to <1>, wherein the above flat pigment (B) is selected from one or more of talc, mica, glass flakes, and aluminum flakes.

[0025] <3> The primer composition according to <1> or <2>, wherein the above olefin resin (A) is substantially free of chlorine.

[0026] <4> The primer composition according to any one of <1> to <3>, wherein the above olefin resin (A) contains a structure derived from maleic anhydride and a structure derived from a (meth)acrylic compound.

[0027] <5> The primer composition according to any one of <1> to <4>, wherein when the above primer composition satisfies the above condition 1, the pigment volume concentration (PVC) in the primer composition is 10 to 60%,

[0028] When the above primer composition satisfies the above condition 2, the pigment volume concentration (PVC) in the primer composition is 30 to 65%,

[0029] When the above primer composition satisfies the above condition 3, the pigment volume concentration (PVC) in the primer composition is 33 to 65%.

[0030] <6> A primer coating film formed from the primer composition according to any one of <1> to <5>.

[0031] <7> A laminated antifouling coating film comprising the primer coating film according to <6> and an antifouling coating film formed on the primer coating film.

[0032] <8> The laminated antifouling coating film according to <7>, wherein the above antifouling coating film is a silicone resin-based antifouling coating film.

[0033] <9> A method for manufacturing a substrate with a primer coating film, comprising the following steps [1] and [2].

[0034] [1] A step of coating the substrate with the primer composition according to any one of <1> to <5>.

[0035] [2] A step of drying the coated primer composition to form a primer coating film.

[0036] <10> A method for manufacturing a substrate with a laminated antifouling coating film, comprising the following steps [i] and [ii].

[0037] [i]Step of forming a primer coating film on a substrate with the primer composition according to any one of <1> to <5>.

[0038] [ii]Step of forming an antifouling coating film on the primer coating film.

[0039] <11>The manufacturing method according to <10>, wherein the antifouling coating film is a silicone resin-based antifouling coating film.

[0040] <12>The manufacturing method according to any one of <9> to <11>, wherein the substrate is a polyolefin-based substrate, a polycarbonate-based substrate, an ABS resin-based substrate, a styrene-butadiene rubber-based substrate, or an ethylene-propylene-diene rubber-based substrate.

[0041] Advantages of the Invention

[0042] According to one embodiment of the present invention, without undergoing a baking treatment using heating, it is possible to form a primer coating film having excellent adhesion to a plastic substrate, and further, it is possible to form a primer coating film that is less likely to peel between the substrate and the primer coating film and between the primer coating film and the antifouling coating film (excellent adhesion to the antifouling coating film) even when an antifouling coating film (particularly a silicone resin-based antifouling coating film) is formed on the primer coating film. Detailed Embodiments

[0043] 《Primer Composition》

[0044] The primer composition of one embodiment of the present invention (hereinafter also simply referred to as "this composition") contains an olefin resin (A) [hereinafter also referred to as "component (A)". The same applies to other components.] and a flaky pigment (B), and satisfies any one of the following conditions 1 to 3.

[0045] Condition 1: The primer composition contains an organic solvent (C) that is not miscible with water, the average particle diameter of the flaky pigment (B) is 25 μm or more, and the content of the flaky pigment (B) is 17% by mass or more with respect to 100% by mass of the solid content of the primer composition.

[0046] Condition 2: The primer composition contains an organic solvent (C) that is not miscible with water, the average particle diameter of the flaky pigment (B) is less than 25 μm, and the content of the flaky pigment (B) is 42% by mass or more with respect to 100% by mass of the solid content of the primer composition.

[0047] Condition 3: The primer composition contains water (D), the olefin resin (A) is an aqueous resin, and the content of the flaky pigment (B) is 50% by mass or more with respect to 100% by mass of the solid content of the primer composition.

[0048] In recent years, from the viewpoints of environmental protection and the safety of the working environment, etc., restrictions on the content of volatile organic compounds (VOC: Volatile Organic Compounds) have become strict, and for various compositions, it is desired to convert from solvent-based compositions to aqueous compositions.

[0049] Since the present composition satisfying the above-mentioned condition 3 can be said to be an aqueous composition, from the viewpoints of environmental protection and the safety of the working environment, etc., it is preferred that the present composition satisfies the above-mentioned condition 3.

[0050] In addition, in the present composition, there may be a case where conditions 1 and 3 are satisfied simultaneously, or a case where conditions 2 and 3 are satisfied simultaneously. In these cases, if the content of water (D) in the composition is less than 5% by mass, it is regarded as the present composition satisfying condition 1 or 2; if the content of water (D) in the composition is 5% by mass or more, it is regarded as the present composition satisfying condition 3.

[0051] Regarding the pigment volume concentration (PVC) in the present composition, from the viewpoints of being able to easily obtain a composition with excellent coating workability and being able to easily form a primer coating film with excellent adhesion to the substrate, etc., in the case of the above-mentioned condition 1, it is preferably 10% or more, more preferably 30% or more, and preferably 60% or less; in the case of the above-mentioned condition 2, it is preferably 30% or more, more preferably 35% or more, preferably 65% or less, and more preferably 60% or less; in the case of the above-mentioned condition 3, it is preferably 33% or more, more preferably 35% or more, preferably 65% or less, and more preferably 60% or less.

[0052] From the above effects and the viewpoints of being able to easily form a primer coating film with excellent adhesion to the antifouling coating film, etc., the PVC in the present composition is preferably 35 to 60%, more preferably 37 to 60%, and particularly preferably 38 to 60%.

[0053] The above-mentioned PVC refers to the volume concentration of the total amount of pigments (component (B) and pigments in the following other components) relative to the volume of the solid components in the present composition. The PVC can be specifically obtained by the following formula.

[0054] PVC [%] = total volume of all pigments in the present composition × 100 / volume of solid components in the present composition

[0055] In addition, in this specification, the solid components of the present composition mean the heating residue obtained in accordance with JIS K5601-1-2 (heating temperature: 125°C, heating time: 60 minutes). Further, the solid components of the present composition can also be calculated as the amount after removing the solvent / dispersion medium that may be included in the raw materials used and the organic solvent / dispersion medium (such as water) that can be used in the preparation of the present composition.

[0056] The volume of the solid components in the above-mentioned present composition can be calculated based on the mass and true density of the solid components of the present composition. The mass and true density of the above-mentioned solid components can be measured values or values calculated based on the raw materials used.

[0057] The volume of the above-mentioned pigment can be calculated by the mass and true density of the pigment used. The mass and true density of the above-mentioned pigment can be measured values or values calculated based on the raw materials used. For example, it can be calculated by separating the pigment from the solid components of the present composition and measuring the mass and true density of the separated pigment.

[0058] The present composition is preferably a primer composition for (direct) coating on a plastic substrate. Even when the present composition is (directly) coated on such a plastic substrate and without undergoing a baking treatment using heating, a primer coating film with excellent adhesion to the substrate can be formed.

[0059] As the above-mentioned substrate, from the viewpoints of further exerting the effects of the present invention, etc., a polyolefin substrate, a polycarbonate substrate, an ABS resin substrate, a styrene-butadiene rubber substrate, or an ethylene-propylene-diene rubber substrate is preferred.

[0060] In addition, the present composition is preferably a primer composition for directly coating an antifouling coating. When forming an antifouling coating film on the primer coating film formed on a plastic substrate, the adhesion to the substrate usually decreases. However, with the present composition, even when an antifouling coating film is formed on the primer coating film formed by the composition, the adhesion to the substrate is excellent, and the adhesion to the antifouling coating film is also excellent.

[0061] The present composition is preferably a composition for curing at normal temperature (usually 5 to 35°C). By using this present composition for curing at normal temperature, compared with the case of using an existing primer composition that requires a baking treatment using heating, a primer coating film can be formed at low cost through a simplified process, and it is also possible to coat a substrate with poor heat resistance. Therefore, the degree of freedom in substrate selection is increased.

[0062] <Olefin resin (A)>

[0063] As the component (A) used in the present composition satisfying the above-mentioned condition 1 or 2, there is no particular limitation, and known olefin resins can be used. In addition, as long as the component (A) used in the present composition satisfying the above-mentioned condition 3 is an aqueous resin (aqueous olefin resin), there is no particular limitation, and known aqueous resins can be used.

[0064] By using the component (A), a primer coating film excellent in adhesion to a plastic substrate can be formed.

[0065] The component (A) used in the present composition may be one kind or two or more kinds.

[0066] The component (A) preferably contains substantially no chlorine. The so-called component (A) contains substantially no chlorine specifically means that the component (A) is not a chloride.

[0067] By using such a component (A) that contains substantially no chlorine, generation of harmful gases such as hydrogen chloride gas can be suppressed even when the substrate having the primer coating film obtained from the present composition is incinerated.

[0068] With the present composition, even when using a component (A) that contains substantially no chlorine, a primer coating film excellent in adhesion to a plastic substrate can be formed.

[0069] Examples of the component (A) include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymers, and copolymers of ethylene and / or propylene with one or more other comonomers (such as vinyl compounds such as α-olefins, conjugated polyenes, non-conjugated polyenes, and vinyl acetate); modified products of the olefin polymers.

[0070] Examples of the above-mentioned α-olefins include α-olefins having 4 to 20 carbon atoms such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 4-methyl-1-pentene.

[0071] As the component (A), a modified product of the above-mentioned olefin polymer is preferred, and a modified product of at least one olefin polymer selected from propylene polymers, ethylene-propylene-diene copolymers (EPDM), and ethylene-vinyl acetate copolymers (EVA) is more preferred.

[0072] Examples of the above-mentioned propylene polymers include homopolymers of propylene; copolymers of propylene and at least one α-olefin other than propylene (the α-olefin preferably having 2 to 15 carbon atoms, more preferably 2 to 10 carbon atoms, and particularly preferably 2, 4, or 5 carbon atoms) (propylene copolymers); copolymers of propylene and at least one comonomer selected from (meth)acrylic acid, (meth)acrylic acid derivatives, styrene, and styrene derivatives, etc. (propylene copolymers).

[0073] The content of the structural unit derived from propylene in the above-mentioned propylene-based copolymer is preferably 50 mol% or more, more preferably 55 mol% or more, preferably 99 mol% or less, and more preferably 85 mol% or less.

[0074] As the above-mentioned EPDM, a copolymer can be cited in which, relative to a total of 100 mol% of the structural unit derived from ethylene, the structural unit derived from propylene, and the structural unit derived from diene, the content of the structural unit derived from ethylene is preferably 40 to 75 mol%, the content of the structural unit derived from propylene is preferably 15 to 55 mol%, and the content of the structural unit derived from diene is preferably more than 0 mol% and 10 mol% or less.

[0075] Examples of the above-mentioned diene include conjugated dienes such as 1,3-butadiene, 1,3-pentadiene, 1,3-octadiene, 1-phenyl-1,3-butadiene, isoprene, 2-ethyl-1,3-butadiene, 2-propyl-1,3-butadiene, 2-octyl-1,3-butadiene, and 2-phenyl-1,3-butadiene; non-conjugated dienes such as norbornadiene, 5-ethylidene-2-norbornene, cyclopentadiene, 1,4-hexadiene, and methylene norbornene.

[0076] As the above-mentioned EVA, a copolymer can be cited in which the content of the structural unit derived from ethylene is preferably 80 mol% or more, more preferably 85 mol% or more, preferably 99 mol% or less, and more preferably 95 mol% or less.

[0077] From the viewpoints of being able to easily form a coating, easily forming a primer coating film with excellent adhesion to a substrate and solvent resistance, etc., the weight-average molecular weight (Mw) of the above-mentioned olefin-based polymer measured by gel permeation chromatography (GPC) is usually 20,000 or more, preferably 50,000 or more, and usually 250,000 or less, preferably 200,000 or less.

[0078] As the above-mentioned modified product, from the viewpoints of considering being able to form a primer coating film with more excellent adhesion to an antifouling coating film, etc., a modified olefin-based polymer modified with at least one modifying component selected from unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, and esters of unsaturated carboxylic acids is preferred.

[0079] This modified product can be obtained, for example, by graft-modifying the above-mentioned olefin-based polymer using the above-mentioned modifying component according to a conventionally well-known method.

[0080] Examples of the above-mentioned unsaturated carboxylic acids include unsaturated monocarboxylic acids and unsaturated polycarboxylic acids (for example, unsaturated dicarboxylic acids). Specific examples include unsaturated monocarboxylic acids such as linoleic acid, linolenic acid, oleic acid, acrylic acid, and methacrylic acid; and unsaturated polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and aconitic acid.

[0081] One or more than two kinds of the above unsaturated carboxylic acids can be used.

[0082] As the acid anhydride of the above unsaturated carboxylic acid, the acid anhydride of the above unsaturated polycarboxylic acid etc. can be cited.

[0083] One or more than two kinds of the acid anhydride of the above unsaturated carboxylic acid can be used.

[0084] As the ester of the above unsaturated carboxylic acid, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, diethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol di(meth)acrylate etc. can be cited.

[0085] One or more than two kinds of the ester of the above unsaturated carboxylic acid can be used.

[0086] In addition, "(meth)acrylic acid" is the general term for acrylic acid and methacrylic acid, meaning one or both of them.

[0087] From the viewpoints such as being able to form a primer coating film with more excellent adhesiveness to a plastic substrate and adhesiveness to an antifouling coating film, component (A) preferably contains a structure derived from maleic anhydride and a structure derived from a (meth)acrylic acid compound.

[0088] In addition, as the (meth)acrylic acid compound, the above acrylic acid, methacrylic acid, and ester of unsaturated carboxylic acid can be cited.

[0089] From the viewpoints such as being able to form a primer coating film with more excellent adhesiveness to a plastic substrate, the modification amount (such as grafting rate) of the above modifier is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, preferably 10% by mass or less, and more preferably 7% by mass or less.

[0090] The above modification amount is the mass of the structure derived from the modifying component in the modifier, and can be obtained by, for example, 1 1H-NMR measurement.

[0091] The melting point of component (A) measured by differential scanning calorimetry (DSC) is preferably 50°C or higher, more preferably 55°C or higher, preferably 120°C or lower, and more preferably 75°C or lower from the viewpoints of enabling easy preparation of a room-temperature curable composition and easy formation of a primer coating film having excellent adhesion to a substrate.

[0092] In the present invention, the "aqueous resin" means a resin having water as a solvent or dispersion medium, or having water as a main solvent or dispersion medium, or a resin that can be mixed with water (dilutable with water). More specifically, water-dispersed resins, water-soluble resins, self-emulsifying resins, etc. can be cited. Such aqueous resins can be synthesized by known publicly available methods, such as solution polymerization, suspension polymerization, emulsion polymerization, seed polymerization, miniemulsion polymerization, microemulsion polymerization, and emulsifier-free (soap-free) emulsion polymerization. In addition to this, aqueous resins can also be obtained by known methods, such as phase inversion emulsification, D-phase emulsification, forced emulsification, gel emulsification, reverse emulsification, and high-pressure emulsification methods for emulsifying olefin resins.

[0093] When component (A) is an aqueous resin and is a water-dispersed resin or a self-emulsifying resin, as a raw material for this component (A), for example, a substance obtained by dispersing fine resin particles having a particle size of 0.1 to 7 μm in a dispersion medium by an emulsifier, a protective colloid, etc. can be used.

[0094] As component (A), a substance synthesized by a known publicly available method can be used, or a commercially available product can be used. As such commercially available products, for example, Arrow Base manufactured by Unitika Ltd., AUROREN manufactured by Nippon Paper Industries Co., Ltd., ZAIKTHENE and SEPOLSION manufactured by Sumitomo Seika Chemicals Co., Ltd., UNISTOLE manufactured by Mitsui Chemicals, Inc., and HARDLEN manufactured by Toyobo Co., Ltd. can be cited.

[0095] Regarding the content (solid content) of component (A), relative to 100% by mass of the solid content of the present composition, in the case of the above condition 1, it is preferably 25% by mass or more, more preferably 30% by mass or more, preferably 75% by mass or less, and more preferably 55% by mass or less; in the case of the above condition 2, it is preferably 25% by mass or more, more preferably 30% by mass or more, preferably 55% by mass or less, and more preferably 50% by mass or less; in the case of the above condition 3, it is preferably 25% by mass or more, more preferably 30% by mass or more, preferably 50% by mass or less, and more preferably 45% by mass or less.

[0096] When the content of component (A) is within the above range, it is easy to form a primer coating film having excellent adhesion to a substrate and an antifouling coating film, not easily generating cracks, and having a good balance and excellent film hardness and flexibility (bending resistance).

[0097] <Flat pigment (B)>

[0098] As the component (B), as long as it satisfies the above-mentioned condition 1 or 2, there is no particular limitation, and it is usually an inorganic pigment having a plate-like structure.

[0099] By using the component (B) that satisfies any one of the above-mentioned conditions 1 to 3, a primer coating film excellent in adhesion to the base material and the antifouling coating film and excellent in rust prevention property and the like can be formed.

[0100] The component (B) used in this composition may be one kind or two or more kinds.

[0101] As the component (B), for example, talc, mica, kaolin, clay, glass flakes, aluminum flakes, scaly iron oxide, stainless steel flakes, plastic flakes can be cited. From the viewpoints of low price, easy availability, and the ability to form a primer coating film with more excellent adhesion to the base material and the antifouling coating film, talc, mica, glass flakes, and aluminum flakes are preferred, and mica is more preferred.

[0102] In the case of the above-mentioned condition 1, the average particle diameter of the component (B) is preferably 25 μm or more, more preferably 30 μm or more, preferably 200 μm or less, and more preferably 150 μm or less.

[0103] In the case of the above-mentioned condition 2, the average particle diameter of the component (B) is preferably 3 μm or more, more preferably 5 μm or more, preferably less than 25 μm, and more preferably 20 μm or less.

[0104] In the case of the above-mentioned condition 3, the average particle diameter of the component (B) is preferably 3 μm or more, more preferably 5 μm or more, preferably 150 μm or less, more preferably 100 μm or less, and further preferably 70 μm or less.

[0105] When the average particle diameter of the component (B) under each condition is within the above range, a primer coating film excellent in adhesion to the base material and the antifouling coating film can be formed.

[0106] The average particle diameter of the component (B) can be calculated by using a scanning electron microscope (SEM), for example, "TM 3030 Plus Miniscope" (manufactured by Hitachi High-Technologies Corporation, desktop SEM) to measure the maximum length of the main surface of any 100 components (B) and calculating their average value.

[0107] In addition, regarding the maximum length of the main surface (the surface with the largest area) of the above-mentioned component (B), for example, when the main surface is a quadrilateral, it means the diagonal length; when the main surface is a circle, it means the diameter; when the main surface is an ellipse, it means the length of the major axis.

[0108] The average aspect ratio of component (B) is not particularly limited, preferably 2 or more, more preferably 3 or more, preferably 100 or less, and more preferably 70 or less.

[0109] When the average aspect ratio is within the above range, component (B) is likely to be horizontally oriented in the primer coating film. Thus, it is possible to easily form a primer coating film excellent in salt water resistance, moisture resistance, etc.

[0110] The aspect ratio of component (B) can be calculated by using a scanning electron microscope (SEM), such as "TM 3030 Plus Miniscope", to measure the thickness and average particle diameter (maximum length of the main surface) of any 100 component (B), and obtaining the average value of the ratio (average particle diameter / thickness) of the two.

[0111] In addition, the thickness of the above component (B) can be measured by observing the main surface of the component (B) from the horizontal direction.

[0112] When the present composition satisfies the above condition 1 or 2, the content of component (B) in the present composition varies depending on the average particle diameter measured as described above.

[0113] That is, when the above average particle diameter is 25 μm or more, the content of component (B) is 17% by mass or more, preferably 30% by mass or more, more preferably 45% by mass or more, preferably 75% by mass or less, and more preferably 65% by mass or less with respect to 100% by mass of the solid content of the present composition.

[0114] In addition, when the average particle diameter is less than 25 μm, the content of component (B) is 42% by mass or more, preferably 45% by mass or more, preferably 70% by mass or less, and more preferably 65% by mass or less with respect to 100% by mass of the solid content of the present composition.

[0115] In addition, when the present composition satisfies the above condition 3, the content of component (B) is 50% by mass or more, preferably 52% by mass or more, preferably 70% by mass or less, and more preferably 65% by mass or less with respect to 100% by mass of the solid content of the present composition.

[0116] When the content of component (B) is within the above range, it is possible to easily form a primer coating film excellent in adhesion to the substrate and the antifouling coating film, and excellent in salt water resistance, moisture resistance, etc.

[0117] <Non-aqueous-miscible organic solvent (C)>

[0118] As the water-immiscible organic solvent (C) described above, as long as it is water-immiscible, there is no particular limitation. For example, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as butyl acetate, alcohol solvents such as benzyl alcohol, mineral spirits, n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane, methylcyclohexane and other aliphatic hydrocarbon solvents can be cited.

[0119] Herein, the so-called "water-immiscible" means that in a mixed liquid obtained by slowly stirring an equal volume of pure water at 20°C, after the flow subsides, the mixed liquid cannot maintain a uniform appearance.

[0120] When the composition satisfying the above condition 1 or 2 contains the above organic solvent (C), the content of the organic solvent (C) is preferably 40% by mass or more, more preferably 50% by mass or more, preferably 90% by mass or less, and more preferably 85% by mass or less based on 100% by mass of the composition.

[0121] <Water (D)>

[0122] In the raw materials such as the component (A) used in the preparation of the composition satisfying the above condition 3, water may be contained. Therefore, the water contained in the raw materials can also be used as the water (D). However, from the viewpoints of being able to more easily prepare the composition and more easily obtaining a composition with more excellent storage stability and coating workability, it is preferred that in the composition satisfying the above condition 3, in addition to the water contained in the raw materials such as the component (A) used in the preparation of the composition, water (D) is further incorporated.

[0123] There is no particular limitation on the water (D), and tap water or the like can be used, and ion-exchanged water, deionized water or the like is preferably used.

[0124] The content of water in the composition satisfying the above condition 3 (including the water that may be contained in the raw materials such as the component (A) used in the preparation of the composition) is not particularly limited, and is preferably 50% by mass or more, more preferably 55% by mass or more, preferably 70% by mass or less, and more preferably 65% by mass or less based on 100% by mass of the composition.

[0125] In addition, regarding the content of water in the composition satisfying the above condition 3, from the viewpoints of being able to easily obtain the desired composition, etc., based on 100% by mass of the total amount of the dispersion medium and the solvent in the composition, it is preferably 50% by mass or more, more preferably 70% by mass or more, particularly preferably 80% by mass or more, and preferably 99% by mass or less.

[0126] <Other components>

[0127] Within the scope that does not impair the effects of the present invention, if necessary, the present composition may also contain other components other than the above components (A) and (B), such as pigments other than component (B), dispersants, defoamers, leveling agents, thickeners, thixotropic agents (anti-sagging agents, anti-settling agents), light stabilizers (light absorbers), adhesion enhancers (such as organic acids, chelating agents, silane coupling agents), and organic solvents other than the above organic solvent (C).

[0128] For these other components, one kind can be used respectively, or two or more kinds can be used.

[0129] [Pigments other than component (B)]

[0130] As pigments other than the above component (B), for example, extender pigments, coloring pigments, and anti-rust pigments can be cited, and they can be either organic or inorganic.

[0131] As the above extender pigments, there is no particular limitation, and known pigments can be used, which are pigments other than the following coloring pigments and anti-rust pigments.

[0132] As the above extender pigments, for example, barium sulfate (including precipitated barium sulfate and elutriated barium sulfate), (potassium) feldspar, bauxite white, magnesium carbonate, barium carbonate, calcium carbonate, dolomite, and silicon dioxide can be cited.

[0133] When the present composition contains extender pigments, the content of the extender pigments is preferably an amount that satisfies the above PVC range. From the viewpoint of being able to easily form a primer coating film with excellent flexibility (anti-bending property), etc., relative to 100% by mass of the solid components of the present composition, it is preferably 0.1% by mass or more, more preferably 1% by mass or more, preferably 25% by mass or less, and more preferably 20% by mass or less.

[0134] As the above coloring pigments, there is no particular limitation, and known pigments can be used.

[0135] As the above coloring pigments, for example, inorganic pigments such as carbon black, titanium oxide (titanium white), iron oxide red (red iron oxide), iron oxide yellow, iron oxide black, and ultramarine blue, and organic pigments such as cyanine blue and cyanine green can be used. Among them, titanium oxide, iron oxide red, and iron oxide black are preferred.

[0136] When the present composition contains coloring pigments, the content of the coloring pigments is preferably an amount that satisfies the above PVC range. Relative to 100% by mass of the solid components of the present composition, it is preferably 0.1% by mass or more, more preferably 1% by mass or more, preferably 25% by mass or less, and more preferably 20% by mass or less.

[0137] Examples of the rust-proof pigment include zinc powder, zinc alloy powder, zinc phosphate compounds, calcium phosphate compounds, aluminum phosphate compounds, magnesium phosphate compounds, zinc phosphite compounds, calcium phosphite compounds, aluminum phosphite compounds, strontium phosphite compounds, aluminum tripolyphosphate compounds, molybdate compounds, zinc cyanamide compounds, borate compounds, nitro compounds, and complex oxides.

[0138] [Thixotropic agent]

[0139] As the above-mentioned thixotropic agent, there can be used the existing known thixotropic agents such as stearates of Al, Ca, Zn, organic clay waxes such as lecithin salts, alkyl sulfonates, clay minerals such as polyethylene wax, bentonite, hectorite, oxidized polyethylene wax, amide wax, polyamide wax, hydrogenated castor oil wax, organic waxes such as synthetic micro powder silica, among which organic clay waxes, clay minerals, oxidized polyethylene wax, amide wax and synthetic micro powder silica are preferred.

[0140] Examples of such thixotropic agents include "DISPARLON 305", "A630-20X", "DISPARLON 6900-20X", "DISPARLON 4200-20", and "DISPARLON 6650" manufactured by Kusumoto Chemicals Co., Ltd., "ASA D-120", "AS-AT-250F", and "AS-AT-55-20BX" manufactured by Ito Oil Products Co., Ltd., and "Bentone DE" manufactured by Elementis Specialties, Inc.

[0141] When the present composition contains a thixotropic agent, the content of the thixotropic agent is preferably 0.1 to 30% by mass based on 100% by mass of the solid content of the present composition.

[0142] [Organic solvents other than the above-mentioned organic solvent (C)]

[0143] The organic solvent other than the organic solvent (C) is not particularly limited, and examples thereof include alcohol solvents such as methanol, ethanol, isopropanol, and propylene glycol monomethyl ether.

[0144] When the present composition satisfying the above condition 1 or 2 contains an organic solvent other than the above organic solvent (C), the content of the organic solvent is preferably 1 to 50% by mass based on 100% by mass of the present composition.

[0145] When the present composition satisfies the above-mentioned condition 3, it is preferred that the composition contains a film-forming aid as an organic solvent other than the above-mentioned organic solvent (C).

[0146] As the above film-forming auxiliary agent, there is no particular limitation, and examples thereof include TEXANOL, ethyl cellosolve, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monobutyl ether, diethylene glycol monobutyl ether (butyl carbitol), and dipropylene glycol monobutyl ether (butyl propylene diglycol).

[0147] When the present composition contains the above film-forming auxiliary agent, the content of the film-forming auxiliary agent is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, preferably 30% by mass or less, and more preferably 20% by mass or less, based on 100% by mass of the present composition.

[0148] <Preparation method of the present composition>

[0149] The present composition can be prepared by mixing (kneading) the above-mentioned respective components.

[0150] During the mixing (kneading), the respective components can be added and mixed at once, or can be added and mixed in multiple times. In addition, heating, cooling, etc. can be carried out while mixing according to seasons, environment, etc.

[0151] During the above mixing (kneading), known mixers, dispersers, stirrers, etc. can be used, and examples thereof include dispersers, mixing / dispersing mills, mortar mixers, rollers, paint mixers, and homogenizers.

[0152] 《Primer coating film, substrate with primer coating film》

[0153] The primer coating film (hereinafter also referred to as "the present coating film") of one embodiment of the present invention is formed using the above-mentioned present composition. The present coating film is usually formed on a substrate and is used in the form of a laminate (substrate with the present coating film) including the present coating film and the substrate (coated object). From the viewpoint of further exerting the effects of the present invention, etc., it is preferred that the substrate is in contact with the present coating film.

[0154] The above substrate with the present coating film is preferably manufactured by a method including the following steps [1] and [2].

[0155] Step [1]: A step of coating the present composition on a substrate.

[0156] Step [2]: A step of drying the coated present composition to form the present coating film.

[0157] The (dry) film thickness of the present coating film is not particularly limited and can be appropriately selected according to the required use. From the viewpoints of fully exerting the effects of the present invention and excellent film-forming properties, etc., it is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 10 μm or more, preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 35 μm or less.

[0158] As the above-mentioned base material, from the viewpoint of further exerting the effects of the present invention, etc., a plastic base material can be cited, preferably a polyolefin base material, a polycarbonate base material, an ABS resin base material, a styrene-butadiene rubber base material or an ethylene-propylene-diene rubber base material, and more preferably a polyolefin base material, a styrene-butadiene rubber base material or an ethylene-propylene-diene rubber base material.

[0159] As the above-mentioned polyolefin, for example, a (co)polymer formed by (co)polymerizing one or more of olefins having 2 to 6 carbon atoms such as ethylene, propylene, and butene can be cited, preferably polyethylene and polypropylene, and more preferably high-density polyethylene (HDPE) and polypropylene.

[0160] As the base material of the above-mentioned material, from the viewpoint of further exerting the effects of the present invention, etc., a base material on which an antifouling coating film needs to be formed on the surface is preferred. For example, marine structures, water structures such as water supply and drainage pipes of thermal power plants and nuclear power plants, seawater utilization equipment, super-large floating marine structures (Mega float), fishery materials (ropes, fishing nets, fishing gear, floats, buoys, etc.), ships, ship equipment, port equipment, etc. Structures or equipment used in water.

[0161] As the coating method of the above-mentioned step [1], there is no particular limitation. For example, known methods such as airless spraying and air spraying can be cited, and coating using a brush, roller, spatula, trowel, etc. Among them, from the viewpoint of being able to easily coat a large-area base material such as the above-mentioned structure, spraying is preferred.

[0162] The conditions of the above-mentioned spraying can be appropriately adjusted according to the (dry) film thickness to be formed as needed. For example, in the case of airless spraying, it is preferably 1st (air) pressure: about 0.1 to 0.4 MPa, 2nd (coating) pressure: about 8 to 15 MPa, and the spray gun moving speed: about 50 to 120 cm / second.

[0163] When applying the present composition to a base material, treatment such as removing grease, moisture, dust, salt, etc. on the base material can also be carried out.

[0164] When applying the present composition, the viscosity can be adjusted to an appropriate value as needed.

[0165] When applying the present composition, it is preferably applied in such a manner that the (dry) film thickness of the obtained present coating film is within the above range. In this case, the required film thickness can be formed by one-time coating (coating once), or a coating film with the required film thickness can be formed by coating two or more times (coating two or more times).

[0166] Herein, applying two or more times means a method of forming a dry coating film on a substrate through the above-mentioned steps [1] and [2] at least once, and then forming a dry coating film on the dry coating film obtained in this step through the above-mentioned steps [1] and [2] again.

[0167] As the drying conditions in the above-mentioned step [2], there are no particular limitations, and they can be appropriately set according to the coating film formation method, the type of substrate, the use, the coating environment, etc. Regarding the drying temperature, in the case of normal temperature drying, it is usually 5 to 35°C; in the case of forced drying using a hot air dryer or the like, it is usually 40°C or higher, more preferably 50°C or higher, usually 100°C or lower, more preferably 80°C or lower. In addition, this forced drying at this temperature is different from the so-called baking treatment usually carried out at a high temperature above 100°C. According to this composition, a coating film with excellent adhesion to a plastic substrate can also be formed by normal temperature drying.

[0168] The drying time varies depending on the drying method of the coating film. In the case of normal temperature drying, it is usually half a day or more, preferably 1 day or more, usually 7 days or less, preferably 3 days or less. In addition, in the case of forced drying, it is preferably 1 hour or more, more preferably 3 hours or more, preferably 12 hours or less, more preferably 9 hours or less.

[0169] "Laminated Antifouling Coating Film and Substrate with Laminated Antifouling Coating Film"

[0170] The laminated antifouling coating film according to one embodiment of the present invention includes this coating film and an antifouling coating film formed on this coating film. An intermediate paint coating film or the like may exist between the above-mentioned this coating film and the antifouling coating film. From the viewpoints of further exerting the effects of the present invention, etc., it is preferred that this coating film is in contact with the antifouling coating film. The above-mentioned laminated antifouling coating film is usually formed on a substrate and is used in the form of a laminate (substrate with a laminated antifouling coating film) that sequentially includes a substrate, this coating film, and an antifouling coating film.

[0171] As the above-mentioned substrate with a laminated antifouling coating film, it is preferably manufactured by a method including the following steps [i] and [ii]. This manufacturing method can also be said to be an antifouling method for the substrate.

[0172] [i] A step of forming this coating film on the substrate from this composition.

[0173] [ii] A step of forming an antifouling coating film on this coating film.

[0174] As the above-mentioned antifouling coating film, there is no particular limitation, and examples thereof include antifouling coating films formed from various conventionally known antifouling paints, such as chlorinated rubber resin-based, vinyl resin-based, hydration decomposition type, non-organotin-based hydrolysis type [metal acrylate resin-based, polyester resin-based, etc.], silicone resin-based, and other antifouling paints. Among them, from the viewpoint of further exerting the effects of the present invention, etc., a silicone resin-based antifouling coating film is preferred.

[0175] As the above-mentioned silicone resin-based antifouling coating film, examples thereof include coating films formed using a silicone resin-containing composition containing an organopolysiloxane having at least two condensation-reactive functional groups. More specifically, examples thereof include coating films formed using conventionally known compositions described in Japanese Patent Laid-Open No. 2001-139816, Japanese Patent Laid-Open No. 2001-181509, and the like.

[0176] From the viewpoint of being able to obtain an antifouling coating film having excellent adhesion to the present coating film, etc., the above-mentioned organopolysiloxane is preferably a compound represented by the following formula [α].

[0177]

[0178] In the above formula [α], W independently represents a hydroxyl group or a hydrolyzable group, and R 1 and R each independently represent an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, n represents an integer of 5 or more, and a represents 0, 1, or 2.

[0179] As such a monovalent hydrocarbon group, for example, a linear or branched alkyl group, alkenyl group, aryl group, cycloalkyl group, or aralkyl group can be cited.

[0180] The weight average molecular weight (Mw) of the above-mentioned organopolysiloxane is preferably 10,000 to 100,000.

[0181] The Mw of the organopolysiloxane is measured using GPC (gel permeation chromatography) and calculated by conversion to a standard polystyrene with a known molecular weight (average molecular weight of the polymer).

[0182] In addition, Mw is a value measured under the following conditions.

[0183] (GPC conditions)

[0184] Apparatus: "HLC-8320GPC" (manufactured by Tosoh Corporation);

[0185] Chromatographic column: "TSKgel guardcolumn SuperMPHZ-M" (manufactured by Tosoh Corporation) × 1 piece + "TSKgelSuperMultiporeHZ-M" (manufactured by Tosoh Corporation) × 2 pieces;

[0186] Eluent: Tetrahydrofuran (THF);

[0187] Flow rate: 0.35 ml / min;

[0188] Detector: RI;

[0189] Column oven temperature: 40 °C;

[0190] Standard substance: Polystyrene;

[0191] GPC measurement sample: The filtrate obtained by filtering the solution of organopolysiloxane after adding the eluent using a membrane filter.

[0192] The (dry) film thickness of the above antifouling coating film is not particularly limited and can be appropriately selected according to the intended use. For example, it is about 100 to 1000 μm.

[0193] As a specific example of the above step [i], a step including the above steps [1] and [2] can be cited.

[0194] As a preferred example of the above step [ii], a step of applying an antifouling coating on this coating film, drying the applied antifouling coating, and curing it as needed can be cited.

[0195] As a method of applying the antifouling coating, a method similar to the method of applying the present composition described above can be cited.

[0196] As the above drying method, for example, a method of leaving it at room temperature for preferably about 0.5 days or more, more preferably about 1 day or more, preferably about 14 days or less, more preferably about 7 days or less can be cited. In addition, when performing this drying, it can also be performed under heating or while blowing air.

[0197] Examples

[0198] Examples are given to explain one embodiment of the present invention in more detail, but the present invention is not limited thereto.

[0199] [Examples 1 to 17 and Comparative Examples 1 to 13]

[0200] Add each component described in Tables 1 to 3 in the amounts (numerical values) described in Tables 1 to 3 to a container and mix well using a high-speed disperser to prepare a primer composition.

[0201] The numerical values of each component in Tables 1 to 3 respectively represent parts by mass. In addition, the descriptions of each component described in Tables 1 to 3 are shown in Table 4.

[0202] <Adhesion 1>

[0203] The primer composition obtained in the examples or comparative examples was sprayed onto a high-density polyethylene plate (substrate) so that the dry film thickness reached 10 μm. After drying at room temperature for 1 day, "Bioclean ECO" (manufactured by Nippon Paint Co., Ltd.), which is a silicone resin-based antifouling paint, was sprayed onto the obtained primer coating film so that the dry film thickness reached 150 μm, thereby laminating an antifouling coating film to produce a substrate with a laminated antifouling coating film.

[0204] On the obtained substrate with a laminated antifouling coating film, a linear incision was made from the antifouling coating film side down to the substrate. The degree of film peeling (primer coating film or antifouling coating film) from the substrate with a laminated antifouling coating film after rubbing the incision part 20 times with a paper towel was evaluated in 5 grades according to the following criteria. The results are shown in Table 1.

[0205] (Evaluation criteria)

[0206] 5: Except for the incision part, the coating film is completely undamaged (no film peeling has occurred at all).

[0207] 4: Film peeling has occurred, and the peeling length at this time is within a range less than 1 mm from the incision part.

[0208] 3: Film peeling has occurred, and the peeling length at this time is within a range more than 1 mm and less than 3 mm from the incision part.

[0209] 2: Film peeling has occurred, and the peeling length at this time is within a range more than 3 mm and less than 10 mm from the incision part.

[0210] 1: Film peeling has occurred, and the peeling length at this time is within a range more than 10 mm from the incision part.

[0211] [Table 1]

[0212]

[0213] <Adhesion 2>

[0214] Except that in the test of the above Adhesion 1, "CMP Bioclean R" (manufactured by Nippon Paint Co., Ltd.), which is a silicone resin-based antifouling paint, was used instead of Bioclean ECO, the same operation as in Adhesion 1 was carried out to evaluate the degree of film peeling from the substrate with a laminated antifouling coating film. The results are shown in Table 2 and Table 3.

[0215] [Table 2]

[0216]

[0217] [Table 3]

[0218]

[0219] [Table 4]

[0220]

[0221] Once an antifouling coating film is formed on a primer coating film formed on a plastic substrate, generally, the adhesion to the substrate decreases. However, with this composition, even when an antifouling coating film is formed on the primer coating film formed by this composition, the adhesion to the substrate is excellent, and the adhesion to the antifouling coating film is also excellent.

Claims

1. A primer composition, characterized in that: it contains an olefin resin (A) and a plate-shaped pigment (B), and satisfies any one of the following conditions 1 and 3, Condition 1: The primer composition contains an organic solvent (C) immiscible with water, the average particle size of the plate-shaped pigment (B) is 25 μm or more, and, based on 100% by mass of the solid content of the primer composition, the content of the plate-shaped pigment (B) is 17% by mass or more; Condition 3: The primer composition contains water (D), the olefin resin (A) is an aqueous resin, and, based on 100% by mass of the solid content of the primer composition, the content of the plate-shaped pigment (B) is 50% by mass or more.

2. The primer composition according to claim 1, characterized in that: the plate-shaped pigment (B) is one or more selected from talc, mica, glass flakes and aluminum flakes.

3. The primer composition according to claim 1 or 2, characterized in that: the olefin resin (A) is substantially chlorine-free.

4. The primer composition according to claim 1 or 2, characterized in that: the olefin resin (A) contains a structure derived from maleic anhydride and a structure derived from a (meth)acrylic acid compound.

5. The primer composition according to claim 1 or 2, characterized in that: when the primer composition satisfies the condition 1, the pigment volume concentration (PVC) in the primer composition is 10 to 60%, when the primer composition satisfies the condition 3, the pigment volume concentration (PVC) in the primer composition is 33 to 65%.

6. A primer coating film, characterized in that: it is formed from the primer composition according to any one of claims 1 to 5.

7. A laminated antifouling coating film, characterized in that: it comprises the primer coating film according to claim 6 and an antifouling coating film formed on the primer coating film.

8. The laminated antifouling coating film according to claim 7, characterized in that: the antifouling coating film is a silicone resin-based antifouling coating film.

9. A method for manufacturing a substrate with a primer coating film, characterized in that: it includes the following steps [1] and [2]: [1] A step of coating the primer composition according to any one of claims 1 to 5 on a substrate; [2] A step of drying the coated primer composition to form a primer coating film.

10. A method for manufacturing a substrate with a laminated antifouling coating film, characterized in that: it includes the following steps [i] and [ii]: [i] A step of forming a primer coating film on a substrate from the primer composition according to any one of claims 1 to 5; [ii] A step of forming an antifouling coating film on the primer coating film.

11. The manufacturing method according to claim 10, characterized in that: the antifouling coating film is a silicone resin-based antifouling coating film.

12. The manufacturing method according to any one of claims 9 to 11, characterized in that: the substrate is a substrate made of polyolefin, polycarbonate, ABS resin, styrene-butadiene rubber or ethylene-propylene-diene rubber.

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