Coating composition

Abstract

A curable coating composition comprising: a) at least one curable polysiloxane-based binder; b) an acrylic polymer; and c) a crosslinker; wherein the acrylic polymer comprises amino, hydroxyl, and carboxylic acid functional groups.

Description

TECHNICAL FIELD

[0001] The present invention relates to a curable anticorrosive coating composition, more specifically to a coating composition comprising at least one curable polysiloxane, a crosslinker and an acrylic polymer having specific functional groups. The present invention also relates to a substrate coated with the coating composition and the use of the coating composition for coating a substrate. BACKGROUND

[0002] Of all steel produced, approximately 85% is carbon steel, which is susceptible to corrosion over time if no measures are taken to protect the steel. The most common method to protect steel structures from corrosion is to apply a traditional solvent borne or water borne organic coating.

[0003] In low corrosive environments, alkyd based coatings are often used as they are single component, surface tolerant and low cost materials. However, alkyd based coatings are generally not well suited for use in high corrosive environments as they do not provide very good corrosion protection. In addition, their appearance is easily discoloured by UV radiation. Solvent borne alkyds also have a high volatile organic compound content (VOC).

[0004] In order to obtain better corrosion resistance, BPA-epoxy resins are sometimes used instead of alkyd based coatings. However, as epoxy resins degrade rapidly when exposed to UV radiation, the coating often requires a topcoat in order to maintain good colour and gloss over the lifetime of the object.

[0005] In addition, BPA-epoxy coatings are often two component coatings, i.e. the separately provided components need to be mixed before application. The complexity of two component coatings requires a certain skill from the applicator. Inexperienced applicators often result in failed coatings due to incorrect mixing of components, use of the wrong coating etc. On the other hand, single component coatings, i.e. coatings that do not require the addition of further components to the composition before application, are easier to handle and reduce the possibility of failed coatings due to component mixing problems and pot life problems.

[0006] WO 1993 / 013179 A1 describes a coating composition comprising a polymer (A) having pendant and / or terminal curable functional groups, at least a majority of the repeat units in polymer (A) being other than siloxane units, and (B) a curable organohydrogenpolysiloxane or polydiorganosiloxane, the curable functional groups in component (A) being capable of undergoing a condensation cure reaction with component (B). However, it does not disclose a coating composition comprising a polysiloxane and an acrylic polymer having amino, hydroxyl and carboxylic acid functional groups.

[0007] WO 1998 / 023691 A1 describes a curable coating composition having a binder comprising a compound or polymer (A) containing at least one primary or secondary amine group, a compound or polymer (B) containing at least one ethylenically unsaturated double bond activated by adjacent electron-withdrawing groups, and a polymer (C) containing at least two silicon-bonded alkoxy groups. However, it does not disclose a coating composition comprising an acrylic polymer having amino, hydroxyl and carboxylic acid functional groups.

[0008] WO 2004 / 067576 A2 describes an ambient temperature curable coating composition comprising a specific branched alkoxy functional polysiloxane, a catalyst and a specific acrylic polymer. The acrylic polymer is essentially free of functional groups that can react with the polysiloxane or the catalyst in the coating composition. However, it does not disclose the use of an acrylic polymer having amino, hydroxyl and carboxylic acid functional groups.

[0009] Therefore, there is still a need for a new curable coating composition having good corrosion resistance and weatherability (e.g. good adhesion in low and high humidity environments). It is also desirable that any such coating does not require the use of an additional topcoat, i.e. is suitable for use both as a primer and as a topcoat, to reduce the number of coating layers required, thereby saving time and money, and reducing the number of products in the paint locker. It is also desirable that it has good storage stability, low VOC, and fast and reliable curing (in low and high humidity environments).

[0010] The present inventors now provide a coating composition that solves the above problems. In particular, the inventors have determined that the use of an acrylic polymer comprising amino, hydroxyl and carboxylic acid functional groups in a coating composition further comprising at least one curable polysiloxane and a crosslinker, provides a coating having excellent corrosion resistance, adhesion and weatherability. Surprisingly, the inventors have also determined that the performance of the present coating is dramatically improved compared to comparative coatings prepared using acrylic polymers that do not comprise or only comprise one or two of the said functional groups. Without wishing to be bound by theory, it appears that the presence of all three functional groups exhibits some sort of synergistic effect on the performance of the composition.

[0011] In addition to having excellent corrosion resistance, adhesion and weatherability, the coating composition according to the present invention is a curable one-component composition (i.e. does not require mixing with additional components prior to application), and is suitable for use both as a corrosion protective primer and as a topcoat, which reduces the complexity for the painter and the number of coating layers required. The coating also has good storage stability, low VOC, and provides fast and reliable curing in low and high humidity environments. SUMMARY

[0012] In one aspect, the present invention relates to a curable coating composition, comprising:

[0013] a) at least one curable polysiloxane alkyl adhesive;

[0014] b) Acrylic polymers; and

[0015] c) Crosslinking agent;

[0016] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0017] In another aspect, the present invention relates to a substrate coated with a coating composition according to any aspect of the invention, wherein the coating composition is optionally cured.

[0018] In another aspect, the present invention relates to the use of a coating composition according to any aspect of the invention for coating a substrate, preferably wherein the coating composition is applied to the substrate as a primer and / or topcoat.

[0019] In another aspect, the present invention provides the use of acrylic polymers comprising amino, hydroxyl and carboxylic acid functional groups in anti-corrosion coating compositions.

[0020] In another aspect, the present invention provides the use of acrylic polymers containing amino, hydroxyl and carboxylic acid functional groups in the preparation of one-component curable coating compositions.

[0021] In another aspect, the present invention relates to a substrate coated with only one layer, the layer comprising a coating composition according to any aspect of the invention, optionally wherein the coating composition is cured.

[0022] definition

[0023] Unless the context allows, the following terms will always be used.

[0024] The term "acrylic polymer" includes polymers of acrylates and acrylamides. Such acrylic polymers can be methacrylic acid or acrylic acid.

[0025] The term "(meth)acrylic acid" refers to acrylic acid or methacrylic acid. Therefore, the term "(meth)acrylate" encompasses methacrylates or acrylates.

[0026] Unless otherwise stated, the percentages of components are calculated on a dry solids basis. This means that the weight contribution of any solvent in the coating composition is ignored.

[0027] As used in this article, the term "polysiloxane" refers to a polymer containing siloxanes, i.e., -Si-O- repeating units.

[0028] As used herein, the term "polysiloxane adhesive" refers to a polysiloxane containing at least 30 wt%, preferably at least 50 wt%, and more preferably at least 70 wt% of repeating units containing the motif -Si-O-, based on the total weight of the polysiloxane. Based on the total weight of the polymer, the polysiloxane adhesive may contain up to 99.99 wt% of repeating units containing the motif -Si-O-. The -Si-O- in the repeating units may be linked in a single sequence or may be interrupted by non-siloxane portions (e.g., organic groups).

[0029] As used in this article, the term "alkyl" refers to a saturated, straight-chain, branched, or cyclic group.

[0030] The term "cycloalkyl" as used in this article refers to cycloalkyl groups.

[0031] As used in this article, the term "alkylene" refers to a divalent alkyl group.

[0032] As used in this article, the term "alkenyl" refers to an unsaturated, straight-chain, branched, or cyclic group.

[0033] As used herein, the term "aryl" refers to a group comprising at least one aromatic ring. The term "aryl" includes fused-ring systems in which one or more aromatic rings are fused to a cycloalkyl ring. An example of an aryl group is the phenyl group, namely C6H5.

[0034] As used herein, the term “substitution” refers to one or more, for example up to six, or more specifically, one, two, three, four, five, or six hydrogen atoms in a group being replaced by the corresponding number of said substituents independently of each other.

[0035] As used in this article, the term "aralkyl" refers to a group in which the alkyl moiety is bonded to Si.

[0036] As used in this article, “volatile organic compounds (VOCs)” refers to compounds with a boiling point of 250°C or lower. Invention Details

[0038] This invention relates to a curable anti-corrosion coating composition, and more specifically, to a coating composition comprising at least one curable polysiloxane binder, a crosslinking agent, and an acrylic polymer having specific functional groups.

[0039] Polysiloxane alkyl adhesives – Component a)

[0040] The coating compositions of the present invention comprise at least one curable polysiloxane binder. The polysiloxane binder in the coating compositions of the present invention can generally be any curable polysiloxane. As used herein, when referring to polysiloxane, the term "curable" means that the polysiloxane contains functional groups that enable a crosslinking reaction to occur directly between polysiloxane molecules or through a crosslinking agent. Preferably, the polysiloxane binder is moisture-curable.

[0041] Polysiloxane adhesives are preferably organopolysiloxanes having terminal and / or side-chain curing reactive functional groups. Each molecule preferably has at least two curing reactive functional groups. Ideally, all curing reactive functional groups are identical. Preferred coating compositions contain polysiloxanes having two or more, preferably three or more, functional groups. Examples of curing reactive functional groups are silanol, alkoxy, acetoxy, alkenoxy, ketoxime, alcohol, amino, epoxy, and / or isocyanate groups, such as silanol, alkoxy, acetoxy, alkenoxy, ketoxime, alcohol, amino, and / or epoxy. The curing reactive functional groups are preferably selected from silanol, alkoxy, or acetoxy. Alkoxy-functionalized polysiloxanes, particularly methoxy-functionalized polysiloxanes, are particularly preferred. The term "alkoxy-functionalized polysiloxane" as used herein includes, but is not limited to, alkoxysilyl-functionalized polysiloxanes. Optionally, polysiloxane adhesives contain more than one type of curing reactive functional group. Preferably, at least one of the polysiloxane alkyl adhesives contains a single type of curable reactive functional group.

[0042] The curing reaction is typically a condensation curing reaction. Polysiloxane adhesives optionally contain more than one type of curing reactive group and can be cured, for example, by condensation curing and amine / epoxy resin curing.

[0043] The polysiloxane binder in the coating composition of the present invention typically contains at least 30 wt% of a polysiloxane portion, preferably more than 50 wt% of a polysiloxane portion, more preferably more than 70 wt% of a polysiloxane portion, for example 99.99 wt% or more of a polysiloxane portion.

[0044] Based on the total weight of at least one polysiloxane, the polysiloxane moiety is defined as a repeating unit containing the motif -Si-O-. The wt% of the polysiloxane moiety can be determined based on the stoichiometric wt ratio of the starting materials in the synthesis of the polysiloxane. Alternatively, the polysiloxane content can be determined using analytical techniques such as IR or NMR. Information on the wt% of the polysiloxane moiety in commercially available polysiloxanes is readily available from suppliers.

[0045] It should be understood that polysiloxane adhesives may comprise polysiloxanes consisting of a single repeating sequence of siloxane units or interrupted by a non-siloxane portion (e.g., an organic portion).

[0046] The organic portion may include, for example, alkylene, arylene, poly(alkylene oxide), amide, thioether or a combination thereof, and preferably the organic portion may include, for example, alkylene, arylene, poly(alkylene oxide), amide or a combination thereof.

[0047] In one embodiment, the polysiloxane adhesive comprises alkoxy (e.g., methoxy) functional groups at the terminal and / or side chain positions. Polysiloxane adhesives containing alkoxy (e.g., methoxy) functional groups at the terminal positions are preferred. In a preferred embodiment, at least one polysiloxane adhesive is a linear or branched alkoxy-functionalized polysiloxane adhesive, preferably a linear or branched methoxy-functionalized polysiloxane adhesive, and more preferably a branched methoxy-functionalized polysiloxane adhesive.

[0048] The coating composition may contain only one type of polysiloxane adhesive, or it may contain a mixture of different polysiloxane adhesives. In one embodiment, component a) of the coating composition comprises a mixture of two or more polysiloxane adhesives, preferably a mixture of a first branched or linear alkoxy-functionalized polysiloxane adhesive and a second branched or linear alkoxy-functionalized polysiloxane adhesive having the same or lower Mw as the first polysiloxane adhesive.

[0049] In a preferred embodiment, the coating composition comprises a branched polysiloxane binder, more preferably a branched alkoxy-functionalized polysiloxane binder. Most preferably, a branched methoxy-functionalized polysiloxane binder. Branched means that the polysiloxane chains are branched. In a preferred embodiment, the branched polysiloxane binder comprises a cage-like polysiloxane structure.

[0050] In a most preferred embodiment, the coating composition comprises a branched polysiloxane binder containing methyl, phenyl, and methoxy groups. In one embodiment, the coating composition comprises a first branched alkoxy-functionalized polysiloxane binder and a second branched alkoxy-functionalized polysiloxane binder having the same or lower Mw as the first polysiloxane binder.

[0051] The preferred curable polysiloxane binder in the coating composition of the present invention is represented by the following formula (D1):

[0052]

[0053] Among them, each R 1 Independently selected from hydroxyl, C 1-6 -alkoxy group, C 1-6 -Hydroxy, containing C 1-6 -Epoxy group, C 1-6 Amine, C 1-10 Alkyl, C 6-10Aryl, C 7-10 alkylaryl or O-Si(R) 5 ) 3-z (R 6 ) z ;

[0054] Each R 2 Independently selected from polyepoxides and / or such as R 1 The group substituted C 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkylaryl or C 1-6 alkyl;

[0055] Each R 3 and R 4 Independently selected from C substituted with polyepoxide 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkylaryl or C 1-6 alkyl;

[0056] Each R 5 Independently, it is a hydrolyzable group, such as C. 1-6 Alkoxy, acetoxy, alkenoxy, or ketoxy;

[0057] Each R 6 Independently selected from unsubstituted or substituted C 1-6 alkyl;

[0058] z is 0 or an integer between 1 and 2;

[0059] x is an integer that is at least 2;

[0060] y is an integer that is 0 or at least 1.

[0061] The preferred curable polysiloxane adhesive for the coating composition of the present invention is represented by the following formula (D1'):

[0062]

[0063] Among them, each R 1 Independently selected from hydroxyl, C 1-6 -alkoxy group, C 1-6 -Hydroxy, containing C 1-6 -Epoxy group, C 1-6 Amine group or O-Si(R) 5 ) 3-z (R 6 ) z ;

[0064] Each R 2 Independently selected from polyepoxides and / or such as R 1The group substituted C 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkylaryl or C 1-6 alkyl;

[0065] Each R 3 and R 4 Independently selected from C substituted with polyepoxide 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkylaryl or C 1-6 alkyl;

[0066] Each R 5 Independently, it is a hydrolyzable group, such as C. 1-6 Alkoxy, acetoxy, alkenoxy, or ketoxy;

[0067] Each R 6 Independently selected from unsubstituted or substituted C 1-6 alkyl;

[0068] z is 0 or an integer between 1 and 2;

[0069] x is an integer that is at least 2;

[0070] y is an integer that is 0 or at least 1.

[0071] Each molecule of preferred formulation D1 or D1' contains at least two curing reactive functional groups.

[0072] Preferred R 1 Selected from hydroxyl and O-Si(R) 5 ) 3-z (R 6 ) z , where R 5 It is a C1-C6 alkoxy group, R 6 It is C 1-6 Alkyl group, z is 0 or an integer from 1 to 2. More preferably R 1 Selected from hydroxyl and O-Si(R) 5 ) 3-z (R 6 ) z , where R 5 It is a C1-C3 alkoxy group, R 6 It is C 1-3 Alkyl group, z is 0 or an integer between 1 and 2. Optimal preference R. 1 It is O-Si(R) 5 )3- z (R 6 ) z , where R 5 It is a C1-C3 alkoxy group, R 6 It is C1-3 Alkyl group, z is 0 or an integer between 1 and 2.

[0073] Preferred R 2 It is C 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkylaryl or O-Si(R) 5 ) 3-z (R 6 ) z .

[0074] Preferred R 3 It is C 1-10 Alkyl or C 6-10 Aryl. More preferably R 3 It is C 1-4 Alkyl or C6 aryl, more preferably C6 1-2 Alkyl or C6 aryl, more preferably methyl or phenyl.

[0075] Preferred R 4 It is C 1-10 Alkyl or C 6-10 Aryl. More preferably R 3 It is C 1-4 Alkyl or C6 aryl, more preferably C6 1-2 Alkyl or C6 aryl, more preferably methyl or phenyl.

[0076] The weight-average molecular weight (Mw) of at least one polysiloxane-based binder in the coating composition of the present invention is generally in the range of 200-50,000 g / mol, preferably 200-10,000, more preferably 400-5000 g / mol, and most preferably 500-2000 g / mol.

[0077] Based on the total dry weight of the composition, the coating composition of the present invention preferably contains 10-95 wt% of component a), more preferably 20 wt% or more, for example 20-80 wt%, for example 20-60 wt%, more preferably 25-60 wt%. In a particularly preferred option, based on the total dry weight of the coating composition, the coating composition contains 20-40 wt%, preferably 25-40 wt% of component a). In a particularly preferred option, based on the total dry weight of the coating composition, the coating composition contains 28-35 wt% of component a).

[0078] When the contribution of solvent to the total weight of the composition is included, the coating compositions of the present invention typically contain 0.1-50 wt% of component a), preferably 10-40 wt%, more preferably 20-40 wt%, based on the total weight of the composition. Component a) of more than 30 wt% is particularly preferred.

[0079] A mixture of polysiloxane adhesives may be used. In this case, the percentages mentioned above refer to the total weight of all polysiloxane adhesives present.

[0080] The coating composition comprises a mixture of two or more polysiloxane adhesives, such as a mixture of a first polysiloxane adhesive and a second polysiloxane adhesive, wherein the weight ratio of the first polysiloxane adhesive to the second or optional other polysiloxane adhesive is typically in the range of 10:1 to 1:1, preferably 5:1 to 1:1, for example, in the range of 5:1 to 2:1.

[0081] In one embodiment, there is a significant difference in viscosity between the two polysiloxane adhesives. For example, the second polysiloxane adhesive may have a viscosity of 5-30 cSt, preferably 8-20 cSt, and the first polysiloxane adhesive may have a viscosity of 70-250 cSt, preferably 90-180 cSt.

[0082] Suitable polysiloxane binders for use in the coating compositions of the present invention are commercially available. Representative commercially available polysiloxane binders include Wacker's REN 50 and REN 80, and Evonik's Silikophen P50X and Silikophen P80X. In a preferred embodiment, the composition comprises a polysiloxane binder selected from Dow Corning 3074, Dow Corning 3037, Silres IC 232, SY231, SY550, and MSE 100.

[0083] acrylic polymer

[0084] The coating compositions of the present invention comprise an acrylic polymer containing amino, hydroxyl, and carboxylic acid functional groups. As described above, the inventors have determined that coating compositions formulated from acrylic polymers having each of these three groups exhibit surprisingly improved properties in terms of adhesion, weather resistance, and corrosion resistance.

[0085] As used herein, the term "amino" refers to a substance with -NX 1 X 2 Any group of the structure, wherein each X 1 and X 2 The amino group is independently selected from H or straight-chain or branched C1-C6 alkyl groups. Therefore, the amino group can be a primary amine, secondary amine, or tertiary amine group, preferably a secondary or tertiary amine.

[0086] The term "hydroxyl" has its common meaning in this field, namely -OH.

[0087] Similarly, the term "carboxylic acid" refers to a group having a -COOH structure. However, in solution, the carboxylic acid group can be deprotonated or exist as a salt, such as -COONa.

[0088] The functionality of the acrylic polymer can be provided by side chain groups and / or terminal groups. In a preferred embodiment, the functionality is provided by the side chain groups (i.e., the monomer itself). Preferably, the acrylic polymer is a copolymer and comprises monomer units containing amino groups, monomer units containing hydroxyl groups, and monomer units containing carboxylic acid groups.

[0089] In a preferred embodiment, the acrylic polymer comprises monomer residue units having structural formula (A):

[0090]

[0091] Wherein, X is NH or O, preferably O;

[0092] R 1 'For H or Me;

[0093] Each R 2 'Independently selected from H, C1-C4 straight-chain or branched alkyl groups, preferably C1-C2 alkyl groups; and

[0094] L 1 It is a straight-chain or branched C1-C6 alkyl linker, preferably a straight-chain C1-C4 alkyl linker.

[0095] The monomer unit can be derived from amino-functionalized monomers, such as 2-(dimethylamino)ethyl(meth)acrylate, 3-(dimethylamino)propyl(meth)acrylate, 2-(diethylamino)ethyl(meth)acrylate, 2-(diisopropylamino)(meth)acrylate, 2-(tert-butylamino)ethyl(meth)acrylate, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide and N-(3-(dimethylamino)propyl)(meth)acrylamide.

[0096] In a preferred embodiment, the monomer unit has structural formula (A) and contains a tertiary amine group such as -NMe2 or -NEt2. In the most preferred embodiment, the monomer unit is derived from the polymerization of 2-(dimethylamino)ethyl (meth)acrylate.

[0097] In a preferred embodiment, the acrylic polymer comprises monomer residue units having structural formula (B):

[0098]

[0099] Among them, R 3'For H or Me; and

[0100] L 2 The alkyl linker is a straight-chain or branched C1-C6 alkyl group, preferably a straight-chain C1-C4 alkyl group. Alkyl linker L 2 One or more carbon atoms in ' can be replaced by one or more hydroxyl groups.

[0101] The monomer unit can be derived from hydroxyl-functionalized monomers, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-1-methylethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and hydroxyisobutyl (meth)acrylate.

[0102] In the most preferred embodiment, the monomer unit is derived from 2-hydroxyethyl (meth)acrylate.

[0103] In a preferred embodiment, the acrylic polymer comprises monomer residue units having the structural formula (C):

[0104]

[0105] Among them, R 4 'For H or Me;

[0106] L 3 'A straight-chain or branched C1-C4 alkyl linker, preferably a straight-chain C1-C2 alkyl linker; and

[0107] n is an integer from 0 to 1, preferably 0.

[0108] Monomer units can be derived from carboxylic acid functional monomers, such as acrylic acid, 2-carboxyethyl acrylate, methacrylic acid, and carboxymethyl methacrylate.

[0109]

[0110] Preferably, carboxylic acid functionality is provided by using methacrylic acid as a monomer.

[0111] In a preferred embodiment, the acrylic polymer comprises all three monomer units (A) to (C).

[0112] Preferably, the acrylic polymer further comprises at least one monomer unit that does not contain amino, hydroxyl, or carboxylic acid functionality. Preferred monomer units are those derived from monomers such as methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, 2-propylheptyl methacrylate, and isodecanyl methacrylate.

[0113] In one embodiment, the acrylic polymer comprises monomer units derived from the polymerization of linear or branched C1-C6 alkyl (meth)acrylate monomers, such as n-butyl (meth)acrylate or methyl methacrylate.

[0114] In one embodiment, the acrylic polymer comprises 50 wt% or more, preferably 60 wt% or more, more preferably 70 wt% or more, and most preferably 80 wt% or more, of monomer units that do not contain amino, hydroxyl, or carboxylic acid functionality. The monomer units that do not contain amino, hydroxyl, or carboxylic acid functionality may, in one embodiment, be derived from the polymerization of linear or branched C1-C6 alkyl (meth)acrylate monomers, such as n-butyl (meth)acrylate.

[0115] In one embodiment, the acrylic polymer contains 1-50 wt% of monomer units comprising amino, hydroxyl, or carboxylic acid functional groups, preferably 1-40 wt%, more preferably 2-30 wt%, and most preferably 5-25 wt%. In a preferred embodiment, the acrylic polymer contains 25 wt% or less of monomer units comprising amino, hydroxyl, or carboxylic acid functional groups, more preferably 20 wt% or less.

[0116] In one embodiment, the acrylic polymer comprises 0.1-20 wt% of monomeric units containing amino functional groups, preferably 0.5-15 wt%, more preferably 1.0-10 wt%.

[0117] In one embodiment, the acrylic polymer comprises 0.1-20 wt% of monomer units containing hydroxyl functional groups, preferably 0.5-15 wt%, more preferably 1.0-10 wt%.

[0118] In one embodiment, the acrylic polymer comprises 0.05-10 wt% of monomer units containing carboxylic acid functional groups, preferably 0.1-10 wt%, more preferably 0.5-5.0 wt%.

[0119] In one embodiment, the acrylic polymer has a glass transition temperature (Tg) of at least 0°C, preferably 10°C or higher, such as 10-25°C, for example 15-25°C. In one embodiment, the acrylic polymer has a Tg greater than 15°C. In one embodiment, the acrylic polymer has a glass transition temperature of less than 100°C, preferably less than 50°C. The glass transition temperature of the polymer can be measured according to ASTM method E1356-08.

[0120] In one embodiment, the acrylic polymer has a viscosity of 1000 cP or higher, preferably 5000 cP or higher, more preferably 10,000 cP or higher.

[0121] In one embodiment, the acrylic polymer has a non-volatile substance content of greater than 50 wt%, preferably greater than 60 wt%, and more preferably greater than 70 wt%.

[0122] In one embodiment, the acrylic polymer has a weight-average molecular weight (Mw) of at least 5000 g / mol, for example at least 7500 g / mol, preferably at least 10,000 g / mol. In another embodiment, the weight-average molecular weight (Mw) of the acrylic polymer is at most 20,000 g / mol, for example at most 15,000 g / mol.

[0123] In one embodiment, the acrylic polymer has a number-average molecular weight (Mn) of at least 3000 g / mol, for example at least 4500 g / mol, preferably at least 5000 g / mol. In another embodiment, the acrylic polymer has a number-average molecular weight (Mn) of up to 15000 g / mol, for example up to 10000 g / mol.

[0124] The polydispersity index (PDI) (defined as Mw / Mn) of the acrylic polymer is preferably in the range of 1-10, more preferably 2-5.

[0125] Based on the total dry weight of the coating composition, the amount of acrylic polymer typically present in the coating composition is 0.1-30 wt%, preferably 0.1-25 wt%, more preferably 1-20 wt%, and most preferably 2-15 wt%. In a particularly preferred option, the acrylic polymer is present at 3-12 wt% based on the total dry weight of the composition. In a particularly preferred option, the acrylic polymer is present at 6-15 wt% based on the total dry weight of the composition.

[0126] Acrylic polymers can be prepared using polymerization reactions known in the art. The polymer can be obtained, for example, in the presence of a polymerization initiator and optionally a chain transfer agent, in a conventional manner or by controlled polymerization techniques, through any mixture of polymeric monomers, such as solution polymerization, bulk polymerization, emulsion polymerization, dispersion polymerization, and suspension polymerization. When preparing coating compositions using such polymers, it is preferable to dilute the polymer with an organic solvent to obtain a polymer solution with a suitable viscosity. From this perspective, solution polymerization is desirable.

[0127] Examples of suitable initiators for free radical polymerization include azo compounds, such as dimethyl azobisisobutyrate, 2,2'-azobisisobutyronitrile, 2,2'-azobisisobutyronitrile, and 1,1'-azo(cyanocyclohexane); and peroxides, such as tert-pentyl peroxide neopentyl ester, tert-butyl peroxide neopentyl peroxide, tert-pentyl-2-ethylhexanoate peroxide, tert-butyl peroxide-2-ethylhexanoate, and 1,1,3,3-tetramethylbutyl peroxide. 2-Ethylhexanoate, tert-butyl diethylacetate peroxide, tert-butyl isobutyrate peroxide, tert-butyl benzoate peroxide, 1,1-di(tert-amylperoxy)cyclohexane, tert-butyl percarbonate-2-ethylhexanoate, tert-butyl peroxyisopropylcarbamate, tert-butyl percarbonate-2-ethylhexyl peroxycarbonate, polyether polytert-butyl peroxycarbonate, di-tert-butyl peroxide, benzoyl peroxide, and cyclohexylene di(1,1-dimethylpropyl) peroxide. These compounds can be used alone or in mixtures of two or more.

[0128] Examples of organic solvents include aromatic hydrocarbons, such as xylene, toluene, and mesitylene; ketones, such as methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl isopentyl ketone, diisobutyl ketone, cyclopentanone, and cyclohexanone; esters, such as butyl acetate, tert-butyl acetate, amyl acetate, ethylene glycol methyl ether acetate, propyl propionate, n-butyl propionate, and isobutyl isobutyrate; ethers, such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dibutyl ether, dioxane, and tetrahydrofuran; alcohols, such as n-butanol, isobutanol, methyl isobutyl methanol, and benzyl alcohol; ether alcohols, such as butoxyethanol and 1-methoxy-2-propanol; terpenes, such as limonene; aliphatic hydrocarbons, such as petroleum solvents; and optionally mixtures of two or more solvents. These compounds can be used alone or in mixtures of two or more. Preferably, it is an aromatic hydrocarbon and a mixture of one or more solvents selected from ketones, esters, ethers, alcohols, and ether alcohols. A mixture of xylene and n-butanol is particularly preferred.

[0129] Crosslinking agent

[0130] In addition to the polysiloxane binder and acrylic polymer, the coating composition of the present invention also includes a crosslinking agent. Upon exposure to moisture, the crosslinking agent suitably reacts with the curing reactive functional groups in the polysiloxane binder to form a crosslinked coating. The crosslinking agent can also suitably be used as an alkaline catalyst for hydrolysis / condensation reactions.

[0131] Those skilled in the art will understand and select a suitable crosslinking agent based on the type of curing reactive functional groups present in the polysiloxane adhesive. If the curing reactive functional group is a silanol or alkoxy group, the preferred crosslinking agent is an organosilicon compound represented by the following general formula, its partially hydrolyzed condensation product, or a mixture of both:

[0132] R d -Si-K 4-d

[0133] Each R is independently selected from an unsubstituted or substituted monovalent hydrocarbon group of 1-6 carbon atoms or a C group substituted with a polyepoxide. 1-6 alkyl.

[0134] Each K is independently selected from a hydrolyzable group, such as an alkoxy group; while d is 0, 1, or 2, more preferably 0 or 1.

[0135] Preferred crosslinking agents of this type include tetraethoxysilane, vinyltris(methylethyloxy)silane, methyltris(methylethyloxy)silane, vinyltrimethoxysilane, methyltrimethoxysilane, and vinyltriisopropoxysilane, as well as their hydrolysis and condensation products. Suitable crosslinking agents are commercially available, such as Wacker's Silcate TES-40WN and Evonik's Dynasylan A.

[0136] If the curing reactive functional group is an amine, epoxy, or isocyanate, the curing agent is preferably an amine, sulfur, or epoxy functional group.

[0137] The crosslinking agent can also be a dual crosslinking agent containing, for example, amine / sulfur / epoxy / isocyanate and alkoxysilyl groups. Preferred dual crosslinking agents are represented by the following general formula:

[0138]

[0139] Wherein, LL is independently selected from unsubstituted or substituted monovalent hydrocarbon groups of 1-6 carbon atoms;

[0140] Each M is independently selected from a hydrolyzable group, such as an alkoxy group;

[0141] a can be 0, 1, or 2, with 0 or 1 being preferred;

[0142] b is an integer from 1 to 6; and

[0143] Fn is an amino group, an epoxy group, a glycidyl ether group, an isocyanate group, or a thiol group. Preferably, Fn is an amino group, an epoxy group, a glycidyl ether group, or a thiol group. More preferably, Fn is an amino group. In the most preferred embodiment, the crosslinking agent is an aminosilane.

[0144] Examples of the aforementioned dual crosslinking agents include 3-propyltrimethoxysilane, 3-propyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (3-glycidoxypropyl)trimethoxysilane, and 3-mercaptopropyltrimethoxysilane. Preferred examples of dual crosslinking agents include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (3-glycidoxypropyl)trimethoxysilane, and 3-mercaptopropyltrimethoxysilane. A particularly preferred crosslinking agent is 3-aminopropyltriethoxysilane, such as Evonik's Dynasylan AMEO.

[0145] In the most preferred embodiment, the crosslinking agent is an organosilane, preferably an aminosilane, such as an aminotrialkoxysilane, like an aminoalkyltrialkoxysilane. If the crosslinking agent is an aminosilane, the amino group is preferably a primary amino group. The ideal molecular weight (Mw) of the aminosilane crosslinking agent is low, for example, 400 g / mol or lower, for example, 50-300 g / mol.

[0146] Preferred options include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, or N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane.

[0147] Preferred crosslinking agents are represented by the following general formula:

[0148]

[0149] Where LL is an unsubstituted C1-C6 alkyl group, such as methyl;

[0150] Each M is an alkoxy group, such as C. 1-4 Alkoxy;

[0151] a is 0 or 1;

[0152] b is an integer from 1 to 6; and

[0153] Fn is an amino group, epoxy group, glycidyl ether group, or thiol group.

[0154] In one embodiment, the crosslinking agent is free of isocyanate groups. Therefore, it is also preferred if the curable polysiloxane adhesive is free of isocyanate groups. Similarly, it is also preferred if the acrylic polymer is free of isocyanate groups. As used herein, the term "free of isocyanate groups" means that such groups are completely absent.

[0155] It is preferable if the curable coating composition of the present invention is substantially free of, for example, any isocyanate functional groups as a whole. "Substantially free of" means that the curable coating composition of the present invention does not contain isocyanate functional groups that can react with curable polysiloxane adhesives or acrylic polymers.

[0156] Preferably, the curable coating composition of the present invention contains less than 0.5 wt% dry weight, for example less than 0.1 wt% dry weight, particularly 0.05 wt% or less dry weight of a compound containing an NCO group.

[0157] Therefore, it is preferable if the curable coating composition of the present invention does not contain components with isocyanate groups.

[0158] Therefore, it is also preferable if the curing coating composition of the present invention does not contain the urethane motif, i.e., -(NCOO-).

[0159] The preferred coating composition is supplied in a curable form, but is kept dry to prevent premature curing.

[0160] Based on the total dry weight of the composition, the crosslinking agent is typically present in an amount of 0.1-10 wt% of the coating composition, preferably in the range of 0.5-6 wt%, and more preferably in the range of 1-6 wt%.

[0161] From another perspective, the present invention provides a curable coating composition comprising:

[0162] a) Based on the total dry weight of the composition, 10-95 wt%, more preferably 25-60 wt%, of at least one curable polysiloxane adhesive;

[0163] b) Based on the total dry weight of the coating composition, 0.1-30 wt%, preferably 0.1-25 wt%, more preferably 1-20 wt%, and most preferably 2-15 wt% of an acrylic polymer; and

[0164] c) Based on the total dry weight of the coating composition, 0.1-10 wt%, preferably in the range of 0.5-6 wt%, more preferably 1-6 wt% of crosslinking agent;

[0165] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0166] From another perspective, the present invention provides a curable coating composition comprising:

[0167] a) At least one curable polysiloxane adhesive, based on 20-60 wt% of the total dry weight of the composition;

[0168] b) Acrylic polymers; and

[0169] c) Crosslinking agent;

[0170] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0171] From another perspective, the present invention provides a curable coating composition comprising:

[0172] a) At least one curable polysiloxane adhesive, based on 25-40 wt% of the total dry weight of the composition;

[0173] b) 2-15 wt% acrylic polymer based on the total dry weight of the composition; and

[0174] c) 1-6 wt% of crosslinking agent based on the total weight of the composition;

[0175] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0176] From another perspective, the present invention provides a curable coating composition comprising:

[0177] a) at least one curable polysiloxane alkyl adhesive;

[0178] b) 0.1-25 wt%, more preferably 1-20 wt%, most preferably 2-15 wt% (dry weight) of an acrylic polymer; and

[0179] c) Crosslinking agent;

[0180] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0181] From another perspective, the present invention provides a curable coating composition comprising:

[0182] a) At least one curable polysiloxane adhesive, based on 20-60 wt% of the total dry weight of the composition;

[0183] b) 2-15 wt% acrylic polymer based on the total dry weight of the composition; and

[0184] c) Crosslinking agent;

[0185] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0186] From another perspective, the present invention provides a curable coating composition comprising:

[0187] a) 10-40 wt%, for example 20-40 wt%, of at least one curable polysiloxane adhesive;

[0188] b) Acrylic polymers; and

[0189] c) Crosslinking agent;

[0190] The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

[0191] The weight ratio of the total polysiloxane adhesive to the acrylic polymer is preferably 1:1 or higher. Therefore, it is preferable if the polysiloxane adhesive is more abundant than the acrylic polymer on a dry weight basis. More preferably, the weight ratio of the polysiloxane adhesive to the acrylic polymer can be from 5:1 to 3:2, for example from 4:1 to 2:1.

[0192] catalyst

[0193] To facilitate the curing process, the coating composition of the present invention preferably contains a catalyst. Representative examples of catalysts that can be used include transition metal compounds, metal salts, and organometallic complexes of various metals, such as tin, iron, lead, barium, cobalt, zinc, antimony, cadmium, manganese, chromium, nickel, aluminum, gallium, germanium, titanium, boron, lithium, potassium, bismuth, and zirconium. The salt is preferably a salt of long-chain carboxylic acids and / or chelates or an organometallic salt.

[0194] Examples of suitable tin-based catalysts include, for example, dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin diacetate, or dioctyltin dilaurate. Examples of commercially available tin catalysts include BNT Chemicals' BNT-CAT 400 and BNT-CAT 500, PMC Organometallix's FASCAT 4202, and DOW's Metatin Katalysator 702.

[0195] Examples of suitable zinc catalysts are zinc 2-ethylhexanoate, zinc naphthenate, and zinc stearate. Examples of commercially available zinc catalysts include King Industries' K-KAT XK-672 and K-KAT670, and Borchers' Borchi Kat 22.

[0196] Suitable bismuth catalysts are organobismuth compounds, such as bismuth 2-ethylhexanoate, bismuth octanoate, and bismuth neodecanoate. Examples of commercial organobismuth catalysts include Borchers' Borchi Kat 24 and Borchi Kat 315, King Industries' K-KAT XK-651, Reaxis' Reaxis C739E50, and TIB Chemicals' TIB KAT716.

[0197] Suitable examples of titanium catalysts are organotitanium catalysts, such as titanium naphthenate, tetrabutyl titanate, tetra(2-ethylhexyl) titanate, triethanolamine titanate, tetra(isopropoxy) titanate, tetrabutyl titanate, tetrapropyl titanate, tetraisopropyl titanate, and chelated titanates such as diisopropyl bis(acetylacetonyl)titanate, diisopropyl bis(ethylacetylacetonyl)titanate, and diisopropoxytitanium bis(ethyl acetoacetate). Suitable commercially available titanium catalysts include Dorf Ketal's Tyzor IBAY and TIB Chemicals' TIB KAT 517.

[0198] Other suitable catalysts are iron catalysts, such as iron stearate and iron 2-ethylhexanoate; lead catalysts, such as lead octanoate and lead 2-ethyloctanoate; cobalt catalysts, such as cobalt 2-ethylhexanoate and cobalt naphthenate; manganese catalysts, such as manganese 2-ethylhexanoate; and zirconium catalysts, such as zirconium naphthenate, tetrabutyl zirconate, tetra(2-ethylhexyl)zirconate, triethanolamine zirconate, tetra(isopropenoxy)-zirconate, tetrabutyl zirconate, tetrapropoxide zirconium, and tetraisopropoxide zirconium.

[0199] Another suitable catalyst is zirconate ester.

[0200] Catalysts can also be organic compounds, such as triethylamine, guanidine, amidine, cyclic amines, tetramethylethylenediamine, 1,4-ethylenepiperazine, and pentamethyldiethylenetriamine. Further examples include aminosilanes, such as 3-aminopropyltriethoxysilane and N,N-dibutylaminomethyltriethoxysilane.

[0201] In a preferred embodiment, the catalyst is a tin, titanium, bismuth, guanidine, and / or amidine catalyst, more preferably a tin, titanium, guanidine, and / or amidine catalyst.

[0202] Preferably, the catalyst is present in the coating composition of the present invention in an amount of 0.01-5 wt%, more preferably 0.05-4 wt%, and most preferably 0.1-3 wt%, based on the total dry weight of the coating composition. In the most preferred embodiment, the catalyst is a tin-based catalyst such as dioctyltin dilaurate, and is present in an amount of 0.1-3 wt% based on the total dry weight of the coating composition.

[0203] Other optional components

[0204] The coating compositions according to the invention may optionally further comprise one or more components selected from other binders, inorganic or organic pigments, expanders and fillers, additives, solvents and diluents.

[0205] Pigments can be inorganic, organic, or mixtures thereof. Inorganic pigments are preferred. Examples of inorganic pigments include titanium dioxide, iron oxide red, iron oxide yellow, iron oxide black, zinc oxide, zinc sulfide, zinc phosphate, lithopone, and graphite. Examples of organic pigments include carbon black, phthalocyanine blue, phthalocyanine green, naphthol red, and pyrrolopyrrole dione red. Pigments may optionally be surface-treated to make them easier to disperse in the coating composition. Inorganic pigments, particularly anti-corrosion pigments, such as zinc phosphate, are preferred.

[0206] Examples of spreaders and fillers are minerals such as dolomite, plastic stone, calcite, quartz, barite, magnesite, silica, nepheline syenite, wollastonite, talc, chlorite, mica, kaolinite, pyrophyllite, and feldspar; synthetic inorganic compounds such as calcium carbonate, magnesium carbonate, barium sulfate, calcium silicate, and silica; polymerized inorganic microspheres such as uncoated or coated hollow and solid glass beads, uncoated or coated hollow and solid ceramic beads; and porous and dense beads of polymeric materials such as poly(methyl methacrylate), poly(methyl methacrylate-co-ethylene glycol dimethacrylate), poly(styrene-co-ethylene glycol dimethacrylate), poly(styrene-co-divinylbenzene), polystyrene, and polyvinyl chloride. The use of feldspar as a spreader in the coating compositions of the present invention is particularly preferred.

[0207] Based on the total dry weight of the composition, the total amount of expander and / or pigment present in the composition of the present invention is preferably 1-60 wt%, more preferably 5-50 wt%, and even more preferably 10-50 wt%. Those skilled in the art will understand that the expander and pigment content will depend on particle size distribution, particle shape, surface morphology, particle surface-resin affinity, other components present, and the end use of the coating composition. In a preferred embodiment, the coating composition contains an expander in an amount of 30-50 wt% of the dry weight of the composition. In a preferred embodiment, the coating composition contains a pigment in an amount of 1-20 wt% of the dry weight of the composition, preferably 1-10 wt%.

[0208] Examples of other additives that can be added to coating compositions include reinforcing agents, rheology modifiers, wetting and dispersing agents, defoamers, and plasticizers.

[0209] Examples of reinforcing agents are sheets and fibers. Fibers include natural and synthetic inorganic fibers, as well as natural and synthetic organic fibers.

[0210] Examples of rheology modifiers include thixotropic agents, thickeners, and antisettling agents. Representative examples of rheology modifiers are silica, such as fumed silica, organic modified clays, amide waxes, polyamide waxes, amide derivatives, polyethylene waxes, oxidized polyethylene waxes, hydrogenated castor oil waxes, ethyl cellulose, aluminum stearate, and mixtures thereof. Rheology modifiers requiring activation can be added to the coating composition as is and activated during the coating production process, or they can be added to the coating composition in a pre-activated form, such as a solvent paste. Based on the total dry weight of the coating composition, it is preferred that each rheology modifier is present in the compositions of the present invention in an amount of 0-5.0 wt%, more preferably 0.2-3.0 wt%, and even more preferably 0.5-2.0 wt%.

[0211] Examples of plasticizers include polymeric plasticizers, chlorinated paraffins, phthalates, phosphates, sulfonamides, adipates, epoxidized vegetable oils, and sucrose isobutyrate. Based on the total dry weight of the coating composition, the plasticizer in the composition of the present invention is preferably present in an amount of 0-10 wt%, more preferably 0.5-7 wt%, and even more preferably 1-5 wt%.

[0212] Dehydrating agents and stabilizers improve the storage stability of coating compositions. Dehydrating agents are preferably compounds that remove moisture and water from the coating composition. They are also known as dehydrating agents or drying agents. Dehydrating agents can be hygroscopic materials that absorb moisture or bind water to form water of crystallization. These are commonly referred to as drying agents. Examples of such compounds include anhydrous calcium sulfate, calcium sulfate hemihydrate, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous zinc sulfate, molecular sieves, and zeolites. Dehydrating agents can also be compounds that chemically react with water. Examples of dehydrating agents that react with water include orthoesters, such as trimethyl orthoformate, triethyl orthoformate, tripropyl orthoformate, triisopropyl orthoformate, tributyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, tributyl orthoacetate, and triethyl orthopropionate; ketals; acetals; enol ethers; orthoboronic esters, such as trimethyl borate, triethyl borate, tripropyl borate, triisopropyl borate, tributyl borate, and tritert-butyl borate; and organosilicones. Alkanes, such as trimethoxymethylsilane, triethoxymethylsilane, tetraethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and polyethyl silicate; oxazolidines, such as 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine and 3-butyl-2-(1-ethylpentyl)-1,3-oxazolidine; and isocyanates, such as p-toluenesulfonyl isocyanate. However, as mentioned above, isocyanate-based compounds are preferred if their use is avoided.

[0213] The stabilizer is preferably an acid remover. Examples of stabilizers are carbodiimide compounds, such as bis(2,6-diisopropylphenyl)carbodiimide, bis(2-methylphenyl)carbodiimide, 1,3-di-p-tolylcarbodiimide, and other compounds as described in WO2014064049.

[0214] Based on the total dry weight of the composition, the dehydrating agent and the stabilizer are preferably present in the composition of the present invention in an amount of 0-5 wt%, more preferably 0.5-2.5 wt%, and more preferably 1.0-2.0 wt%, respectively.

[0215] It is particularly preferred if the coating composition contains a solvent. This solvent is preferably volatile and, more preferably, organic. Examples of organic solvents and diluents are aromatic hydrocarbons such as xylene, toluene, and mesitylene; ketones such as methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl isopentyl ketone, methyl pentanyl ketone, diisobutyl ketone, cyclopentanone, and cyclohexanone; esters such as butyl acetate, tert-butyl acetate, amyl acetate, isopentyl acetate, propyl propionate, n-butyl propionate, and isobutyl isobutyrate; ether esters such as ethylene glycol methyl ether acetate and ethyl 3-ethoxypropionate; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dibutyl ether, dioxane, and tetrahydrofuran; alcohols such as n-butanol, isobutanol, methyl isobutyl methanol, and benzyl alcohol; ether alcohols such as butoxyethanol and 1-methoxy-2-propanol; terpenes such as limonene; aliphatic hydrocarbons such as petroleum solvent oils; and mixtures of two or more solvents and diluents by choice.

[0216] The preferred solvent is an aromatic solvent, especially a mixture of xylene and aromatic hydrocarbons.

[0217] The amount of solvent is preferably as low as possible. The solvent content can be up to 45 wt% of the composition, preferably up to 40 wt%, for example up to 35 wt%, but can be as low as 15 wt% or less, for example 10 wt% or less. In one embodiment, the solvent is present in an amount of at least 1 wt%, preferably at least 5 wt% of the total composition. Similarly, those skilled in the art will understand that some raw materials contain solvents and contribute to the total solvent content as described above, and that the solvent content will vary depending on the other components present and the end use of the coating composition.

[0218] Alternatively, the coating can be dispersed in an organic non-solvent of the film-forming component of the coating composition, in an aqueous dispersion.

[0219] Coating composition

[0220] The coating composition of the present invention preferably has a solids content of more than 40 vol%, for example, more than 45 vol%, for example, more than 50 vol%, preferably more than 60 vol%. In one embodiment, the coating composition has a solids content of up to 80 vol%, for example, up to 70 vol%. The method for measuring volumetric solids is based on ISO 3233.

[0221] The preferred coating composition should have a volatile organic compound (VOC) content of less than 500 g / L, preferably less than 420 g / L, more preferably less than 400 g / L, and for example less than 380 g / L. In the most preferred embodiment, the VOC content is less than 210 g / L. The VOC content can be calculated (ASTM D5201-01) or measured, for example as described in US EPA Method 24 or ISO 11890-2.

[0222] In a preferred embodiment, the coating composition is provided as a single-component composition. As used herein, the term "single-component" means that the composition does not need to be mixed with additional components to ensure curing before application to a substrate. Alternatively, the coating composition may be provided as a kit, for example, with the crosslinking agent supplied separately from the polysiloxane and / or acrylic polymer.

[0223] application

[0224] In one aspect, the present invention relates to a substrate coated with the coating composition of the present invention. The coating composition of the present invention can be applied to all or part of the surface of any object subjected to corrosion / weathering. The substrate is typically metallic, such as the floor and railings of a ship or the surface of a fixed marine object (e.g., an oil platform). Steel substrates are particularly preferred.

[0225] The application of the coating composition can be accomplished by any convenient method, such as by painting (e.g., with a brush or roller) or by spraying the coating onto the substrate. The application of the coating is achieved in a manner conventionally known in the art.

[0226] The coating composition can be applied directly to the substrate. It can also be applied on top of a coating layer such as a primer. Applying the coating composition directly to the substrate, such as directly to metal, is preferred.

[0227] A topcoat can be applied on top of the coating composition of the present invention. Preferably, there is no topcoat layer. It is preferable if the coating composition is applied directly to the substrate, for example, directly to metal, without a topcoat layer. One aspect of the invention relates to the use of the coating composition as a single layer applied directly to a substrate. The coating composition of the present invention may be the only layer present.

[0228] It is understood that the coating compositions of the present invention may need to be applied in the form of multiple layers in order to build a layer of sufficient thickness on the substrate. We consider the application of multiple layers of the same coating composition herein to produce a single layer.

[0229] In a preferred embodiment, the coating composition of the present invention is curable at room temperature, i.e., when exposed to moisture, the composition will cure at the temperature of the environment in question without the application of heat. This is typically in the range of 0-50°C. Preferably, curing occurs below 40°C, more preferably at room temperature, i.e., in the range of 12-35°C. It is understood that because the coating compositions of the present invention are curable, they may be referred to as curable coating compositions. In a preferred embodiment, the coating composition is moisture-curable. In a preferred embodiment, the coating composition cures at a humidity of 30-85%.

[0230] The layer formed using the coating composition of the present invention preferably has a dry film thickness of 40-400 μm, more preferably 80-175 μm, for example 100-150 μm. It is understood that any layer can be laid using single or multiple coating applications.

[0231] The invention will now be further described with reference to the following embodiments.

[0232] Determination methods

[0233] Polymer solution viscosity

[0234] The viscosity of the acrylic polymer was measured at 12 rpm using a Brookfield DV-I viscometer with an LV-2 or LV-4 rotor, according to ASTM D2196 Test Method A. The polymer solution was tempered to 23.0℃ ± 0.5℃ prior to measurement.

[0235] Determination of non-volatile content of acrylic polymer solutions

[0236] The nonvolatile matter content in the polymer solution was determined according to ISO 3251. A test sample of 0.5 g ± 0.1 g was taken and dried in a ventilated oven at 150 °C for 30 minutes. The weight of the residual material was considered the nonvolatile matter (NVM). The NVM content was expressed as a weight percentage. The given value is the average of three parallel measurements.

[0237] Determination of molecular weight

[0238] Polymers were characterized by gel permeation chromatography (GPC). Molecular weight distribution (MWD) was determined using the Malvern Omnisec Resolve and Reveal system, employing two tandem Agilent PLgel 5 μm Mixed-D columns with tetrahydrofuran (THF) as eluent at a constant flow rate of 1 mL / min and a refractive index (RI) detector. The columns were calibrated using Agilent's narrow-band polystyrene standards, Polystyrene Medium EasiVials (4 mL), in red, yellow, and green. Both column and detector temperatures were maintained at 35 °C. Injection volume was 100 μL. Data were processed using Malvern's Omnisec 5.1 software.

[0239] Samples were prepared by dissolving a polymer solution corresponding to 25 mg of dry polymer in 5 mL of THF. Samples were kept at room temperature for at least 3 hours before sampling for GPC measurements. Samples were filtered through a 0.45 μm nylon filter prior to analysis. Weight-average molecular weight (Mw) and polydispersity index (PDI, expressed as Mw / Mn) are reported in the table.

[0240] Determination of glass transition temperature

[0241] Glass transition temperature (Tg) was obtained by differential scanning calorimetry (DSC). DSC measurements were performed on a TA Instruments DSC Q200. Samples were prepared by drop-coating a polymer solution onto a glass plate with a gap size of 100 μm using a spreader. The glass plate was dried overnight at room temperature, followed by drying at 50 °C for 24 hours in a ventilated heating cabinet. Approximately 10 mg of the dried polymer material was scraped off the glass plate and transferred to an aluminum pot. The pot was sealed with a non-sealing lid. Measurements were performed by running a hot-cold-hot program over a temperature range of -50 °C to 120 °C at a heating rate of 10 °C / min and a cooling rate of 10 °C / min, using an empty pot as a reference. Data were processed using TA Instruments' general-purpose analysis software. The inflection point of the glass transition range after the second heating, as defined in ASTM E1356-08, was reported as the Tg of the polymer.

[0242] Example: Synthesis of acrylic polymers

[0243] General procedure for the preparation of acrylic polymers IP1 and CP1-CP5

[0244] A certain amount of solvent is charged into a temperature-controlled reaction vessel equipped with a stirrer, condenser, nitrogen inlet, and feed inlet. The reaction vessel is heated and maintained at the reaction temperature. A premix of monomer and initiator is prepared. The premix is ​​charged into the reaction vessel at a constant rate under nitrogen conditions over 2 hours. The reaction vessel is then maintained at the reaction temperature for another 2 hours. Finally, the reactor is cooled to room temperature.

[0245] The composition and polymerization conditions for preparing the copolymer are listed in Table 1 below. All quantities are parts by weight.

[0246] An overview of the functional groups in the synthetic polymers is listed in Table 2.

[0247] Table 1: Synthesis of Acrylic Polymer

[0248]

[0249]

[0250] Table 2: Overview of Functional Groups in Acrylic Polymers

[0251] Acrylic polymer Functionality IP1 OH, NMe2, COOH CP1 OH CP2 COOH CP3 None CP4 OH, NH CP5 NH

[0252] Preparation of coating compositions

[0253] The coating composition was prepared using a high-speed dissolver. An acrylic polymer was added after the grinding stage.

[0254] The coating composition IE1 of the present invention and comparative coating compositions CE1-CE5, each containing different acrylic polymers listed in Table 2, were prepared. The components of the compositions are shown in Table 3.

[0255] Table 3: Components of the coating composition (wt%).

[0256]

[0257]

[0258] 1 Mw: 700-1500 Daltons, viscosity: 8-20 cSt (25℃), methoxy content: 15-18 wt%, methyl / phenyl ratio: 0.25 / 1.0. 2 Dow Corning's DC3074, Mw: 1200-1700 Daltons, viscosity: 90-180 cSt (25℃), methoxyl content: 15-18wt%.

[0259] Weather resistance test

[0260] The coating compositions in Table 3 were applied directly to the steel plate using a brush, and the weather resistance of the coatings was tested in a humidity test. This method is based on standard ASTM D2247-11, "Standard practice for testing the water resistance of coatings at 100% relative humidity" (2011). The tensile strength of the coating system was recorded, and the fracture type was evaluated according to the description in ISO 4624:2016. The degree of blistering was evaluated according to the description in ISO 4628-2:2016. The results are shown in Table 4 below.

[0261] Table 4: Results of moisture resistance test.

[0262]

[0263] The MPa values ​​and fracture types obtained in the test are reported. Evaluation of fracture properties after the pull-out test:

[0264] A represents the cohesive failure of the substrate;

[0265] A / B represents the adhesion failure between the substrate and the first coating layer;

[0266] B represents the cohesive failure of the first coating layer;

[0267] B / C represents the adhesion failure between the first and second coating layers;

[0268] n represents the cohesive failure of the nth layer in a multilayer coating system;

[0269] n / m represents the adhesion failure between the nth and mth layers in a multilayer coating system;

[0270] Y represents the cohesive failure of the adhesive.

[0271] Adhesion failure refers to the breakdown of the interface between the coating and the substrate or between two coating layers, while cohesive failure refers to the breakdown within a single coating layer or within the substrate.

[0272] Foaming is assessed by the number (density) and size of bubbles, where 0 indicates no visible foam and 5 indicates the highest degree of foaming. The assessment is based on ISO 4628.

[0273] Humidity test results showed that IE1 performed best overall. This formulation was the only one that did not foam (higher numbers indicate more foaming) and exhibited no cohesive breakage. This indicates that all three functional groups must be present to achieve optimal performance in the humidity test.

[0274] Salt spray exposure test

[0275] The resistance of the coating compositions IE1 and CE3 in Table 3 to neutral salt spray exposure was tested according to ISO 12944. This was achieved by sandblasting a 3mm thick steel plate (Sa 2). 1 / 2) A coating is applied to a 150mm × 75mm surface to prepare the panel. The film thickness of each coating layer is 150 micrometers WTF. The second coating layer is applied one day after the first layer is applied, for a total of two layers.

[0276] The test was conducted in a salt spray chamber for 1440 hours (C5-high marine, ISO 12944). The results are shown in Table 5 below.

[0277] Table 5: Results of Neutral Salt Spray Exposure Tests

[0278]

[0279] Salt spray results showed that IE1 exhibited slightly better corrosion creep resistance than CE3 (a smaller number indicates better corrosion creep resistance). However, regarding blistering, IE1 was significantly superior to CE3 (a higher number indicates a wider blistering range).

[0280] Therefore, compositions containing acrylic polymers having amino, hydroxyl, and carboxyl functional groups have been shown to have better moisture and corrosion resistance than compositions containing acrylic polymers without these functional groups.

Claims

1. A curable coating composition, said curable coating composition comprising: a) at least one curable polysiloxane alkyl adhesive; b) Acrylic polymer; and c) Crosslinking agent; The acrylic polymer comprises amino, hydroxyl, and carboxylic acid functional groups; and Wherein, the weight ratio of the curable polysiloxane adhesive to the acrylic polymer is 1:1 or higher; Wherein, the at least one curable polysiloxane alkyl adhesive has the structural formula (D1'): （D1'）； Among them, each R 1 Independently selected from hydroxyl, C 1-6 -alkoxy group, C 1-6 -hydroxyl group, C 1-6 - Contains epoxy groups, C 1-6 Amine group or O-Si(R) 5 )3- z (R 6 ) z ; Each R 2 Selected independently from C 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkyl aryl groups or polyepoxides and / or such as R 1 The C group substituted by the group 1-6 alkyl; Each R 3 and R 4 Selected independently from C 1-10 Alkyl, C 6-10 Aryl, C 7-10 alkyl aryl or C substituted with polyepoxide 1-6 alkyl; Each R 5 Independently a hydrolyzable group; Each R 6 Independently selected from unsubstituted or substituted C 1-6 alkyl; z is 0 or an integer between 1 and 2; x is an integer that is at least 2; y is an integer that is 0 or at least 1; Wherein, the crosslinking agent has the formula ； Wherein, LL is independently selected from unsubstituted or substituted monovalent hydrocarbon groups of 1 to 6 carbon atoms; Each M is independently selected from hydrolyzable groups; a is 0, 1, or 2; b is an integer from 1 to 6; and Fn is an amino group, an epoxy group, a glycidyl ether group, or a thiol group; The curable polysiloxane adhesive and the crosslinking agent do not contain isocyanate groups.

2. The coating composition according to claim 1, wherein, The acrylic polymer comprises monomer residue units having the following structural formula: ； Where X is NH or O; Among them, R 1' For H or Me; Each R 2' Independently selected from H, C1-C4 straight-chain or branched alkyl groups; and L 1' It is a straight-chain or branched C1-C6 alkyl linker.

3. The coating composition according to claim 1 or 2, wherein, The acrylic polymer comprises monomer residue units having the following structural formula: ； Among them, R 3' For H or Me; and L 2' It is a straight-chain or branched C1-C6 alkyl linker, optionally substituted with one or more hydroxyl groups.

4. The coating composition according to claim 1, wherein, The acrylic polymer comprises monomer residue units having the following structural formula: ； Among them, R 4' For H or Me; L 3' It is a straight-chain or branched C1-C4 alkyl linker; and n is an integer between 0 and 1.

5. The coating composition according to claim 1, wherein, The acrylic polymer contains 1-50 wt% monomer units including amino, hydroxyl, or carboxylic acid functional groups.

6. The coating composition according to claim 1, wherein the acrylic polymer comprises 5-25 wt% of monomer units including amino, hydroxyl, or carboxylic acid functional groups.

7. The coating composition according to claim 1, wherein, The at least one curable polysiloxane adhesive is a linear or branched alkoxy-functional polysiloxane adhesive.

8. The coating composition according to claim 1, wherein, The at least one curable polysiloxane adhesive is a branched methoxymethylphenylsiloxane.

9. The coating composition according to claim 1, wherein, The weight-average molecular weight (Mw) of the at least one curable polysiloxane alkyl adhesive is 200-50,000 g / mol, and the weight-average molecular weight is determined by GPC.

10. The coating composition according to claim 1, wherein, The weight-average molecular weight (Mw) of the at least one curable polysiloxane alkyl adhesive is 500-2,000 g / mol, and the weight-average molecular weight is determined by GPC.

11. The coating composition according to claim 1, wherein, The crosslinking agent is an organosilane.

12. The coating composition according to claim 1, wherein, Based on the total weight of the composition, component a) is present in the coating composition in an amount of 0.1-50 wt%.

13. The coating composition according to claim 1, wherein, Based on the total weight of the composition, component a) is present in the coating composition in an amount of 20-40 wt%.

14. The coating composition according to claim 1, wherein, Based on the total dry weight of the composition, component a) is present in the coating composition in an amount of 10-95 wt%.

15. The coating composition according to claim 1, wherein, Based on the total dry weight of the composition, component a) is present in the coating composition in an amount of 25-40 wt%.

16. The coating composition according to claim 1, wherein, The acrylic polymer is present in an amount of 0.1-30 wt% of the total dry weight of the coating composition.

17. The coating composition according to claim 1, wherein, The acrylic polymer is present in an amount of 3-12 wt% of the total dry weight of the coating composition.

18. The coating composition according to claim 1, wherein, The crosslinking agent is present in an amount of 0.1-10 wt% of the total dry weight of the coating composition.

19. The coating composition according to claim 1, wherein, The crosslinking agent is present in an amount of 1-6 wt% of the total dry weight of the coating composition.

20. The coating composition according to claim 1, wherein, The coating composition also includes anti-corrosion pigments.

21. The coating composition according to claim 1, wherein, The coating composition also includes zinc phosphate.

22. The coating composition according to claim 1, wherein, The coating composition also includes a catalyst.

23. The coating composition according to claim 1, wherein, The coating composition further includes a catalyst selected from dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin diacetate, or dioctyltin dilaurate.

24. The coating composition according to claim 1, wherein, The coating composition has a solids content greater than 60 vol% and / or a volatile organic compound (VOC) content less than 210 g / L.

25. The coating composition according to claim 24, wherein, The content of volatile organic compounds was determined using ISO 11890-2.

26. The coating composition according to claim 1, wherein, The coating composition does not contain isocyanate functional groups.

27. A curable coating composition according to claim 1, wherein, The curable coating composition includes: a) Based on the total dry weight of the composition, 20-60 wt% of at least one curable polysiloxane alkyl adhesive; b) Acrylic polymers; and c) Crosslinking agent; The acrylic polymer includes amino, hydroxyl, and carboxylic acid functional groups.

28. A substrate coated with a coating composition according to any one of claims 1-27, wherein, Optionally, the coating composition is cured.

29. A substrate according to claim 28, coated with only one layer.

30. Use of a coating composition according to any one of claims 1 to 27 in coating a substrate, wherein the coating composition is applied to the substrate as a primer and / or topcoat.

Images