CN115838563A - Dry-mix powder coating composition - Google Patents
Dry-mix powder coating composition Download PDFInfo
- Publication number
- CN115838563A CN115838563A CN202211533476.2A CN202211533476A CN115838563A CN 115838563 A CN115838563 A CN 115838563A CN 202211533476 A CN202211533476 A CN 202211533476A CN 115838563 A CN115838563 A CN 115838563A
- Authority
- CN
- China
- Prior art keywords
- component
- powder coating
- coating composition
- epoxy resin
- polyester resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
The present invention relates to a dry-blended powder coating composition comprising a first component comprising a polyester resin A and an epoxy resin A, and a second component comprising a polyester resin B and an epoxy resin B, wherein the polyester resin A has an acid value of 70 to 120mgKOH/g, the polyester resin B has an acid value of 30 to 50mgKOH/g, and the epoxy resin A comprises a non-bisphenol A type epoxy resin. Also disclosed are substrates coated with the dry blended powder coating compositions.
Description
Technical Field
The invention relates to the field of solid coatings, in particular to a dry-mixed powder coating composition cured at low temperature.
Background
The powder coating is a solid coating which does not contain solvent and volatile matter, and has the advantages of harmlessness, environmental protection, high efficiency, low price and the like. In recent years, with the continuous increase of environmental protection strength at home and abroad and the continuous improvement of environmental protection consciousness of users, the demand of powder coating in various fields is more and more urgent. The powder coating is widely applied to the fields of automobiles, pipelines, household appliances, furniture, aluminum profiles and the like at present.
Generally, existing powder coatings are cured at relatively high temperatures, for example at least 150 ℃, which places considerable limitations on the application of powder coatings to heat-sensitive substrates. For this reason, those skilled in the art have been devoted to develop a powder coating that cures under low temperature conditions so that it can be applied to various heat-sensitive substrates, such as MDF fiberboard and the like. However, it is a real difficulty how to make the powder coating have excellent mechanical and appearance properties under the low-temperature curing condition.
Therefore, the development of the low-temperature cured powder coating with various mechanical and appearance properties has urgent practical significance and excellent development prospect.
Disclosure of Invention
In view of the above-mentioned technical problems, the present inventors have conducted extensive studies and developed a powder coating composition which can be cured under low temperature conditions and thus is suitable for heat-sensitive substrates such as MDF fiberboard. The powder coating composition has excellent mechanical and appearance properties. Moreover, the powder coating composition also has environmental protection properties and has a low BPA (bisphenol A) content.
In one aspect, the present invention provides a dry-mix powder coating composition comprising a first component comprising a polyester resin a and an epoxy resin a and a second component comprising a polyester resin B and an epoxy resin B, wherein the polyester resin a has an acid value of 70 to 120mgKOH/g, the polyester resin B has an acid value of 30 to 50mgKOH/g, and the epoxy resin a comprises a non-bisphenol a type epoxy resin.
In another aspect, the present invention provides a coated substrate comprising a substrate and the dry blended powder coating composition coated on at least a portion of the substrate.
Detailed Description
Other than in the examples, or where otherwise explicitly indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently has certain errors. This error is a corollary to the standard deviation found in their respective methods of measurement.
Moreover, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, i.e., having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.
In this application, the use of the singular includes the plural and plural encompasses singular, unless expressly stated otherwise. In addition, in this application, the use of "or" means "and/or" unless explicitly stated otherwise, even though "and/or" may be explicitly used in some cases. In addition, in this application, the use of "a" means "at least one" unless explicitly stated otherwise. For example, "a" coating, etc. refers to any one or more of the items. And features of one embodiment may be used with other embodiments as will be recognized by those skilled in the art, even if not explicitly stated herein.
As used herein, the term "powder coating" refers to a solid powdered coating comprised of ingredients such as resins, curing agents, pigments, fillers and/or adjuvants. The "powder" refers to a substance dried at room temperature (i.e., 20 to 30 ℃) and atmospheric pressure, which is in a fine, loose granular state. In general, the maximum size of the individual particles in the powder coating does not exceed 200. Mu.m, wherein the particle size can be obtained by sieve analysis.
As used herein, the term "dry-blended" means that the components of the coating composition are mixed by dry-blending in a mixer or blender. The method is simple to operate and saves cost, but in order to ensure the appearance effect of the coating film, the compatibility and consistency among the components are required.
The powder coating compositions according to the invention are cured by radiation heat, for example infrared heat. The term "cure" means that the ingredients in the powder coating become "fixed", i.e. form an irreversible crosslinked network. In the powder coating of the present invention, the groups contained in the resin may react with the groups contained in the curing agent to form a crosslinked network; alternatively, the groups contained in the resin may react with other groups present in the resin to crosslink.
The powder coating composition according to the invention is low temperature curable. Suitably, the powder coating composition is curable at 120-140 ℃ for 3-5 min in an infrared heat curing regime.
The powder coating compositions according to the invention have a low BPA content. Suitably, the powder coating composition contains BPA in an amount of not more than 0.1wt%, based on the total weight of the powder coating composition, and even the BPA content may be 0wt%. The BPA content can be obtained by gas chromatography.
The powder coating composition according to the invention can form a coating having a matte effect. Suitably, the powder coating composition forms a coating having a gloss value at 60 ° of no more than 40%, such as no more than 30%, even no more than 20%, such as 15%. The gloss values can be obtained by measurement with a commercially available gloss meter.
The powder coating composition according to the invention can form a coating layer having high smoothness. Suitably, the PCI leveling rating > =6 rating for the coating formed from the powder coating composition. The levelling rating can be determined by reference to the GBT 1750-1979 standard.
In one aspect, the present invention provides a dry mix powder coating composition comprising a first component comprising a polyester resin a and an epoxy resin a and a second component comprising a polyester resin B and an epoxy resin B, wherein the polyester resin a has an acid value of 70 to 120mgKOH/g, the polyester resin B has an acid value of 30 to 50mgKOH/g, and the epoxy resin a comprises a non-bisphenol a type epoxy resin.
The powder coating composition according to the present invention comprises different polyester resins and different epoxy resins, wherein the polyester resins and the epoxy resins are curing agents for each other, involving multiple curing mechanisms (including between the polyester resins and the epoxy resins in the same component, and between the polyester resins and the epoxy resins in different components), so that the powder coating can be effectively cured at low temperatures and advantageously obtain the desired matte effect. Also, the resin selection in the first and second components is particularly advantageously applicable to the multiple cure mechanism of the present invention, giving coatings with excellent and balanced mechanical and appearance properties under low temperature cure conditions.
A first component
Suitably, the polyester resin A may have an acid value of 70mgKOH/g, an acid value of 80mgKOH/g, an acid value of 90mgKOH/g, an acid value of 100mgKOH/g, an acid value of 110mgKOH/g, or an acid value of 120 mgKOH/g. The acid number is the number of milligrams of potassium hydroxide required to neutralize the free acid in 1 gram of resin and can be determined by titration.
The polyester resin a may have a viscosity of 500 to 3000cps, such as 500 to 2000 cps. For example, the polyester resin a may have a viscosity of 500cps, a viscosity of 600cps, a viscosity of 700cps, a viscosity of 800cps, a viscosity of 900cps, a viscosity of 1000cps, a viscosity of 1200cps, a viscosity of 1400cps, a viscosity of 1600cps, a viscosity of 1800cps, or a viscosity of 2000 cps. The viscosity can be determined according to GB/T28841-1 using a Brookfield IELD2000+ H cone and plate viscometer.
The polyester resin a may have a softening point of 90 to 110 ℃. For example, the polyester resin a may have a softening point of 90 ℃, a softening point of 95 ℃, a softening point of 100 ℃, a softening point of 105 ℃, or a softening point of 110 ℃. The softening point can be determined by the method of GB/T12007.6-1989.
The polyester resin a may have a glass transition temperature of 45 to 60 ℃. For example, the ester resin a may have a glass transition temperature of 45 ℃, a glass transition temperature of 50 ℃, a glass transition temperature of 55 ℃, or a glass transition temperature of 60 ℃. The glass transition temperature can be determined by dynamic thermomechanical analysis (DMA) using a TA Instruments Q800 apparatus with a frequency of 10Hz, an amplitude of 5mm, a temperature ramp of-100 ℃ to 250 ℃, tg determined as the peak of the tan δ curve according to ASTM D7028.
The polyester resin a may be present in the first component in an amount of 40wt% or more, 45wt% or more, or 50wt% or more, and/or 70wt% or less, 65wt% or less, or 60wt% or less, based on the total weight of the first component. Suitably, the polyester resin a may be present in the first component in an amount ranging from 40 to 70 weight percent, from 45 to 65 weight percent, from 50 to 60 weight percent, or any combination thereof, based on the total weight of the first component.
The epoxy resin A comprises non-bisphenol A type epoxy resin. The non-bisphenol A epoxy resin refers to an epoxy resin which does not adopt bisphenol A as a synthetic raw material. Suitably, the majority (at least 80 wt%) of the epoxy resin a is a non-bisphenol a type epoxy resin. For example, all of the epoxy resins a are non-bisphenol a type epoxy resins.
The epoxy resin a may have an epoxy equivalent of not more than 300g/eq, such as 150 to 250 g/eq. Suitably, the epoxy resin a may have an epoxy equivalent weight of 150g/eq, an epoxy equivalent weight of 160g/eq, an epoxy equivalent weight of 170g/eq, an epoxy equivalent weight of 180g/eq, an epoxy equivalent weight of 190g/eq, an epoxy equivalent weight of 200g/eq, an epoxy equivalent weight of 210g/eq, an epoxy equivalent weight of 220g/eq, an epoxy equivalent weight of 230g/eq, an epoxy equivalent weight of 240g/eq, or an epoxy equivalent weight of 250 g/eq. The epoxy equivalent means the mass of the resin containing 1mol of epoxy groups, and can be measured by a titration method.
The epoxy resin a may have a functionality of 3 or higher. Suitably, the epoxy resin may have a functionality of 3, a functionality of 4, a functionality of 5, or a functionality of 6. The functionality refers to the number of functional groups per molecule of compound that can participate in the reaction.
The epoxy resin a may have a softening point of 80 to 100 ℃. For example, the epoxy resin a may have a softening point of 80 ℃, a softening point of 85 ℃, a softening point of 90 ℃, a softening point of 95 ℃, or a softening point of 100 ℃. The softening point can be determined by the method of GB/T12007.6-1989.
The epoxy resin a may be present in the first component in an amount of 8wt% or more, 10wt% or more, or 15wt% or more, and/or 40wt% or less, 35wt% or less, or 30wt% or less, based on the total weight of the first component. Suitably, the epoxy resin a may be present in the first component in an amount ranging from 8 to 40 weight percent, from 10 to 35 weight percent, from 15 to 30 weight percent, or any combination thereof, based on the total weight of the first component.
Suitably, the weight ratio of the polyester resin a to the epoxy resin a may be 5. Different resin selections result in differences in reaction rates, leveling, and compatibility, which can affect the final cure and surface state of the coating. The combination of polyester resin a and epoxy resin a imparts beneficial properties to the powder coating and its weight ratio affects the degree of cure and reaction speed of the powder coating.
In the dry-mix powder coating composition of the present invention, the polyester resin a and the epoxy resin a constitute the film-forming resin of the first component. By "consisting" is meant that the film-forming resin comprises a major proportion by weight (at least 80 wt%) of polyester resin a and epoxy resin a. Suitably, the sum of the weight of the polyester resin a and the epoxy resin a is 80wt% or more, such as 90wt% or more, even 100wt%, based on the total weight of the film-forming resin of the first component.
The first component may further include a curing catalyst to further promote curing of the above polyester resin a and the above epoxy resin a. Suitable curing catalysts may include quaternary ammonium salts, quaternary phosphonium salts, and/or imidazoles. The curing catalyst may be present in the first component in an amount of 0.5 to 2.5wt%, such as 0.6 to 2wt%, or 0.7 to 1.5wt%, based on the total weight of the first component.
The combination of the polyester resin a, the epoxy resin a and the optional curing catalyst described above allows for a reasonably fast curing speed of the first component. The first component may have a gel time of no more than 120 seconds at 130 ℃. For example, the first component may have a gel time of 120 seconds, 110 seconds, 100 seconds, 90 seconds, 80 seconds, 70 seconds, 60 seconds, 50 seconds, 40 seconds, 30 seconds, 20 seconds at 130 ℃. The "gel time" refers to the time required for the composition (first component/second component/powder coating) to change from a molten to a non-flowable state at a given temperature, i.e., 130 ℃. In this context, the "gel time" can be determined according to the GB/T1699-1997 standard.
The first component is substantially free of an additional curative component, wherein the additional curative component is a component other than the polyester resin a and the epoxy resin a that is capable of chemically crosslinking with the film-forming resin. For example, the additional curative component may be one or more selected from the group consisting of: glycidyl ester curing agents, hydroxyalkyl amide curing agents, isocyanate curing agents, carboxylic acid curing agents, amine curing agents and polyphenol curing agents. By "substantially free" it is meant that the additional curative component is present in the first component in an amount of less than 0.05wt%. Suitably, the first component does not contain an additional curative component (at a level of 0 wt%).
The first component may also include a pigment filler (i.e., a pigment and/or a filler). The pigments and fillers may impart color and/or visual effects to the powder coating and/or improve the relevant mechanical properties of the powder coating, such as abrasion resistance, corrosion resistance, stability, etc. Typically, the pigment and filler may be present in the first component in an amount of about 10 to 30wt%, based on the total weight of the first component.
The first component may also include one or more auxiliary ingredients/adjuvants. The auxiliary components include, but are not limited to, antifouling agents, powdering agents, coupling agents, anti-blocking agents, anti-scratching agents, antistatic agents, antibacterial agents, anti-aging agents, slip agents, flame retardants, viscosity modifiers, leveling agents, degassing agents, antioxidants, and the like. When used, the content of the auxiliary components can be adjusted by those skilled in the art according to actual needs. Generally, the amount of the auxiliary ingredient may be not more than 2wt% each, based on the total weight of the first component.
A second component
Suitably, the polyester resin B may have an acid value of 30mgKOH/g, an acid value of 35mgKOH/g, an acid value of 40mgKOH/g, an acid value of 45mgKOH/g, or an acid value of 50 mgKOH/g. The acid number is the number of milligrams of potassium hydroxide required to neutralize the free acid in 1 gram of resin and can be determined by titration.
The polyester resin B may have a viscosity of 1000 to 5000cps, such as 2500 to 5000 cps. For example, the polyester resin B may have a viscosity of 2500cps, a viscosity of 3000cps, a viscosity of 3500cps, a viscosity of 4000cps, a viscosity of 4500cps, or a viscosity of 5000 cps. The viscosity can be determined according to GB/T28841-1 using a Brookfield IELD2000+ H cone and plate viscometer.
The polyester resin B may have a softening point of 100 to 120 ℃. For example, the polyester resin B may have a softening point of 100 ℃, a softening point of 105 ℃, a softening point of 110 ℃, a softening point of 115 ℃, or a softening point of 120 ℃. The softening point can be determined by the method of GB/T12007.6-1989.
The polyester resin B may have a glass transition temperature of 50 to 70 ℃. For example, the ester resin B may have a glass transition temperature of 50 ℃,55 ℃,60 ℃,65, or 70 ℃. The glass transition temperature can be determined by dynamic thermomechanical analysis (DMA) using a TA Instruments Q800 apparatus with a frequency of 10Hz, an amplitude of 5mm, a temperature ramp of-100 ℃ to 250 ℃, tg determined as the peak of the tan δ curve according to ASTM D7028.
The polyester resin B may be present in the second component in an amount of 30wt% or more, 35wt% or more, or 40wt% or more, and/or 60wt% or less, 55wt% or less, or 50wt% or less, based on the total weight of the second component. Suitably, the polyester resin B may be present in the second component in an amount ranging from 30 to 60wt%, from 35 to 55wt%, from 40 to 50wt%, or any combination of the foregoing values, based on the total weight of the second component.
The epoxy resin B may include an epoxy resin obtained by one-step synthesis. For example, the epoxy resin B can be obtained by polycondensation of bisphenol a and epichlorohydrin with NaOH.
The epoxy resin B may include a non-bisphenol a type epoxy resin. The non-bisphenol A epoxy resin refers to an epoxy resin which does not adopt bisphenol A as a synthetic raw material. Suitably, the epoxy resin B may be a one-shot synthetically obtained epoxy resin and/or a non-bisphenol a epoxy resin.
The epoxy resin B may have an epoxy equivalent of at least 500g/eq, such as 550 to 1000 g/eq. Suitably, the epoxy resin B may have an epoxy equivalent of 550g/eq, an epoxy equivalent of 600g/eq, an epoxy equivalent of 650g/eq, an epoxy equivalent of 700g/eq, an epoxy equivalent of 750g/eq, an epoxy equivalent of 800g/eq, an epoxy equivalent of 850g/eq, an epoxy equivalent of 900g/eq, an epoxy equivalent of 950g/eq, or an epoxy equivalent of 1000 g/eq. The epoxy equivalent means the mass of the resin containing 1mol of epoxy groups, and can be measured by a titration method.
The epoxy resin B may have a viscosity of 500 to 3000cps, such as 1000 to 3000cps. For example, the epoxy resin B may have a viscosity of 1000cps, a viscosity of 1500cps, a viscosity of 2000cps, a viscosity of 2500cps, or a viscosity of 3000cps. The viscosity can be determined according to GB/T28841-1 using a Brookfield IELD2000+ H cone and plate viscometer.
The epoxy resin B may have a softening point of 70 to 100 ℃. For example, the polyester resin B may have a softening point of 70 ℃, a softening point of 75 ℃, a softening point of 80 ℃, a softening point of 85 ℃, a softening point of 90 ℃, a softening point of 95 ℃, or a softening point of 100 ℃. The softening point can be determined by the method of GB/T12007.6-1989.
The epoxy resin B may be present in the second component in an amount of 20wt% or more, 25wt% or more, or 30wt% or more, and/or 50wt% or less, 45wt% or less, or 40wt% or less, based on the total weight of the second component. Suitably, the epoxy resin B may be present in the second component in an amount ranging from 20 to 50 weight percent, from 25 to 45 weight percent, from 30 to 40 weight percent, or any combination of the foregoing values, based on the total weight of the second component.
Suitably, the weight ratio of the polyester resin B to the epoxy resin B may be 3. The polyester resin B and the epoxy resin B in a specific type and proportion enable the second component to have relatively slow reaction speed, relatively good leveling property and relatively good flexibility, and also have poor compatibility with the first component, so that extinction is facilitated.
In the dry-mix powder coating composition of the present invention, the polyester resin B and the epoxy resin B constitute a film-forming resin of the second component. By "consisting" is meant that the film-forming resin comprises a major proportion by weight (at least 80 wt%) of polyester resin B and epoxy resin B. Suitably, the sum of the weight of the polyester resin B and the epoxy resin B is 80wt% or more, such as 90wt% or more, even 100wt%, based on the total weight of the film-forming resin of the second component.
The second component may further include a curing catalyst to further promote curing of the polyester resin B and the epoxy resin B. Suitable curing catalysts may include quaternary ammonium salts, quaternary phosphonium salts, and/or imidazoles. The curing catalyst may be present in the second component in an amount of 0 to 0.8wt%, such as 0wt%,0.1 to 0.8wt%,0.2 to 0.6wt%, based on the total weight of the second component.
The combination of polyester resin B, epoxy resin B, and optional curing catalyst described above, allows the second component to have a reasonably slow cure speed. The second component may have a gel time of at least 300 seconds at 130 ℃. For example, the second component may have a gel time of 350 seconds, 400 seconds, 450 seconds, 500 seconds, 550 seconds, 600 seconds, 650 seconds, or 700 seconds at 130 ℃. The "gel time" refers to the time required for the composition (first component/second component/powder coating) to change from a molten to a non-flowable state at a given temperature, i.e., 130 ℃. In this context, the "gel time" can be determined according to the GB/T1699-1997 standard.
The second component is substantially free of an additional curative component, wherein the additional curative component is a component other than the polyester resin B and the epoxy resin B that is capable of chemically crosslinking with the film-forming resin. For example, the additional curative component may be one or more selected from the group consisting of: glycidyl ester curing agents, hydroxyalkyl amide curing agents, isocyanate curing agents, carboxylic acid curing agents, amine curing agents and polyphenol curing agents. By "substantially free" it is meant that the additional curative component is present in the second component in an amount of less than 0.05wt%. Suitably, the second component does not contain an additional curative component (at a level of 0 wt%).
The second component may also include a pigment filler (i.e., a pigment and/or a filler). The pigments and fillers may impart color and/or visual effects to the powder coating and/or improve the relevant mechanical properties of the powder coating, such as abrasion resistance, corrosion resistance, stability, etc. Typically, the pigment and filler may be present in the second component in an amount of about 10 to 30wt%, based on the total weight of the second component.
The second component may also include one or more auxiliary ingredients/adjuvants. The auxiliary components include, but are not limited to, antifouling agents, powdering agents, coupling agents, anti-blocking agents, anti-scratching agents, antistatic agents, antibacterial agents, anti-aging agents, slip agents, flame retardants, viscosity modifiers, leveling agents, degassing agents, antioxidants, and the like. When used, the content of the auxiliary components can be adjusted by those skilled in the art according to actual needs. Generally, the amount of the auxiliary ingredient may be not more than 2wt% each, based on the total weight of the second component.
In the dry mix powder coating composition of the present invention, the above-mentioned first component and the above-mentioned second component are mixed in an appropriate ratio. Suitably, the weight ratio of the first component to the second component may be 5:5
The first component and the second component need to have different gel times. For example, the gel time of the first component is shorter than the gel time of the second component at the same temperature. Suitably, the first component and the second component may have a difference in gel time at 130 ℃ of 200 seconds or more. For example, the first component and the second component may have a difference in gel time at 130 ℃ of 200 seconds, 250 seconds, 300 seconds, 350 seconds, 400 seconds, 450 seconds, 500 seconds, 550 seconds, 600 seconds, or 650 seconds. The "gel time difference" is the difference between the gel time of the second component minus the gel time of the first component.
After dry blending, the first component and the second component may have a gel time of 50 to 250 seconds at 130 ℃. For example, after dry blending, the gel time of the first component and the second component at 130 ℃ may be 50 seconds, 70 seconds, 90 seconds, 110 seconds, 130 seconds, 150 seconds, 170 seconds, 190 seconds, 210 seconds, 230 seconds, or 250 seconds. The gel time of the first component and the second component after dry blending is also the gel time of the powder coating composition.
After dry blending, the ingredients of the first component interact with the ingredients of the second component, for example, between polyester resin a and polyester resin B and/or epoxy resin B, between epoxy resin a and polyester resin B and/or epoxy resin B. Thus, proper cooperation between the first component and the second component promotes low temperature cure and enhances the appearance and mechanical properties of the coating.
Advantageously, the acid value of the polyester resin a in the first component is higher than the acid value of the polyester resin B in the second component. Suitably, the difference in acid value between the polyester resin a in the first component and the polyester resin B in the second component may be from 20 to 90mgKOH/g. For example, the difference in acid value between polyester resin A in the first component and polyester resin B in the second component may be 20mgKOH/g,30mgKOH/g,40mgKOH/g,50mgKOH/g,60mgKOH/g,70mgKOH/g,80mgKOH/g, or 90mgKOH/g. The "acid value difference" is the acid value of the polyester resin A in the first component minus the acid value of the polyester resin B in the second component.
Advantageously, the viscosity of the polyester resin a in the first component is lower than the viscosity of the polyester resin B in the second component. Suitably, the difference in viscosity between the polyester resin a in the first component and the polyester resin B in the second component may be from 500 to 4000cps, such as from 800 to 3000cps. For example, the difference in viscosity between the polyester resin a in the first component and the polyester resin B in the second component may be 800cps,1000cps,1500cps,2000cps,2500cps, or 3000cps. The "viscosity difference" is the viscosity of the polyester resin B in the second component minus the viscosity of the polyester resin a in the first component.
Advantageously, the epoxy equivalent weight of the epoxy resin a in the first component is lower than the epoxy equivalent weight of the epoxy resin B in the second component. Suitably, the difference in epoxy equivalent between the epoxy resin a in the first component and the epoxy resin B in the second component may be from 400 to 750g/eq. For example, the difference in epoxide equivalent weight between the epoxy resin a in the first component and the epoxy resin B in the second component may be 400g/eq,450g/eq,500g/eq,550g/eq,600g/eq,650g/eq,700g/eq, or 750g/eq. The "difference in epoxy equivalent" is the epoxy equivalent of epoxy resin B in the second component minus the epoxy equivalent of epoxy resin A in the first component.
The dry-mix powder coating composition according to the invention can be prepared by:
(1) Mixing polyester resin A, epoxy resin A, a curing catalyst, pigment and filler and/or an auxiliary agent to prepare a first composition;
(2) Mixing polyester resin B, epoxy resin B, a curing catalyst, pigment and filler and/or an auxiliary agent to prepare a second composition; and
(3) The first component composition and the second component composition are mixed in an appropriate ratio, and then melt-extruded, cooled, ground, tableted, crushed, pulverized and sieved to prepare a powder coating composition.
The present invention also provides a coated substrate comprising a substrate and the above dry mixed powder coating composition coated on at least a portion of the substrate. Also, the present invention provides a use of the dry-mixed powder coating composition for coating a substrate. The substrate may comprise a heat-sensitive substrate, such as an MDF substrate.
The substrate may comprise a treated and/or coated substrate. The substrate may also include untreated and/or uncoated substrates. The treatment may include pre-treatment operations such as cleaning, sanding, and the like. Suitably, the substrate may comprise any shape of substrate. The substrate may include a sharp edge.
The dry mix powder coating composition according to the present invention may be applied to a substrate using any conventional powder coating application method. The dry-mixed powder coating composition may then be cured at 120-140 ℃ for 3-5 min in an infrared heat cure mode.
The dry-mix powder coating compositions according to the invention can form coatings with a dry film thickness of 70 to 120 μm.
Examples
The following examples are provided to further illustrate the invention but are not to be construed as limiting the invention to the details set forth in the examples. All parts and percentages in the following examples are by weight unless otherwise indicated.
Example 1
First and second components were prepared according to the ingredients and ratios shown in table 1 below, respectively, and then the first and second components were mixed at 5:5 to give a dry-mixed powder coating composition Ex1 according to the invention.
TABLE 1 Dry mix powder coating composition Ex1 according to the invention
Note:
polyester resin A: the acid value is 90-110 mgKOH/g, and the viscosity is 1000-2000 cps;
epoxy resin A: non-bisphenol A type epoxy resin, the epoxy equivalent is 180-200 g/eq;
polyester resin B: the acid value is 30-50 mgKOH/g, and the viscosity is 3000-4000 cps;
epoxy resin B: non-bisphenol A type epoxy resin, the epoxy equivalent is 600-650 g/eq;
curing catalyst: quaternary ammonium salt or quaternary phosphonium salt catalysts;
pigment and filler: including titanium white, carbon black, and/or calcium carbonate;
auxiliary agent: including leveling agents, benzoin, defoaming agents, and/or wax powders.
Example 2
First and second components were prepared according to the ingredients and ratios shown in table 2 below, respectively, and then the first and second components were mixed at 5:5 to give a dry-mixed powder coating composition Ex2 according to the invention.
TABLE 2 Dry-mix powder coating composition Ex2 according to the invention
Note:
polyester resin A: the acid value is 80-100 mgKOH/g, and the viscosity is 1000-2000 cps;
epoxy resin A: non-bisphenol A type epoxy resin, the epoxy equivalent is 170-190 g/eq;
polyester resin B: the acid value is 30-50 mgKOH/g, and the viscosity is 3000-4000 cps;
epoxy resin B: one-step bisphenol A type epoxy resin with the epoxy equivalent of 750-800 g/eq;
curing catalyst: quaternary ammonium salt or quaternary phosphonium salt catalysts;
pigment and filler: including titanium white, carbon black, and/or calcium carbonate;
auxiliary agent: including leveling agents, benzoin, defoaming agents, and/or wax powders.
Example 3
First and second components were prepared according to the ingredients and ratios shown in table 3 below, respectively, and then the first and second components were mixed at 5:5 to give a dry-mixed powder coating composition Ex3 according to the invention.
TABLE 3 Dry-mix powder coating composition Ex3 according to the invention
Note:
polyester resin A: the acid value is 75-95 mgKOH/g, and the viscosity is 1000-2000 cps;
epoxy resin A: non-bisphenol A epoxy resin, the epoxy equivalent is 200-220 g/eq;
polyester resin B: the acid value is 30-50 mgKOH/g, and the viscosity is 3000-4000 cps;
epoxy resin B: one-step bisphenol A type epoxy resin with epoxy equivalent of 850-900 g/eq;
curing catalyst: quaternary ammonium salt or quaternary phosphonium salt catalysts;
pigment and filler: including titanium white, carbon black, and/or calcium carbonate;
auxiliary agent: including leveling agents, benzoin, defoaming agents, and/or wax powders.
Comparative example 1
First and second components were prepared according to the ingredients and ratios shown in table 4 below, respectively, and then the first and second components were mixed at 5:5 to give a dry-mixed powder coating composition CE1 of the comparative example.
TABLE 4 Dry-blended powder coating composition CE1 of the comparative examples
Note:
polyester resin A: the acid value is 75-95 mgKOH/g, and the viscosity is 1000-2000 cps;
polyester resin B: the acid value is 30-50 mgKOH/g, and the viscosity is 3000-4000 cps;
epoxy resin B: one-step bisphenol A type epoxy resin with epoxy equivalent of 850-900 g/eq;
curing catalyst: quaternary ammonium salt or quaternary phosphonium salt catalysts;
pigment and filler: including titanium white, carbon black, and/or calcium carbonate;
auxiliary agent: including leveling agents, benzoin, defoaming agents, and/or wax powders.
The dry-mixed powder coating compositions Ex1, ex2 and Ex3 according to the invention and comparative example CE1 were applied to MDF substrates respectively and then cured at 120 to 140 ℃ for 3 to 5min using an infrared heat curing method to give coatings with a thickness of 80 to 100 μm. The coated substrate was subjected to the following performance tests:
The surface gloss value of the coated substrate at an angle of 60 ° was measured using a haze-gloss meter (Byk-Gardner).
| Ex1 | Ex2 | Ex3 | CE1 | |
| 60 degree gloss | 28 | 33 | 22 | 65 |
In this context, the levelling rating can be determined by reference to the GBT 1750-1979 standard, in particular by the following method:
a Powder sample to be tested is taken and uniformly sprayed with a Coating film having a film thickness of 90-120 μm on a standard laboratory pre-treated aluminum plate (length X width =8cmX15cm, thickness 0.6 mm), and then a naked eye Visual comparison is carried out on a Powder Coating special leveling standard comparison plate (Powder Coating materials Standards-Set of 10 Standards with a Coating raw from 1 to 10 for Visual Reference) manufactured by ACT company in America. The standard ratio plate has 10 blocks, which are respectively 1-10 grades, the grade 1 has the worst leveling, and the grade 10 has the best leveling.
| Ex1 | Ex2 | Ex3 | CE1 | |
| Leveling rating | 6.5 | 6 | 6.5 | 5.5 |
In this context, the impact resistance can be determined according to the standard of GB/T1732-1993, in particular by the following method:
and (3) the weight is lifted to a height corresponding to certain impact strength, then the weight is enabled to freely fall by releasing hands, and whether the coating cracks or not is observed.
| Ex1 | Ex2 | Ex3 | CE | |
| Regular impact, 20kg.cm | Does not crack | Does not crack | Does not crack | Cracking of |
From the above, it can be seen that the dry-blended powder coating compositions Ex1, ex2 and Ex3 according to the present invention are effectively cured under low temperature conditions, and the resulting coatings have excellent matte effect and leveling effect, and excellent mechanical properties, such as impact resistance, compared to the comparative examples.
While particular aspects of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
Claims (17)
1. A dry mix powder coating composition comprising a first component comprising a polyester resin a and an epoxy resin a and a second component comprising a polyester resin B and an epoxy resin B, wherein the polyester resin a has an acid value of 70 to 120mgKOH/g, the polyester resin B has an acid value of 30 to 50mgKOH/g, and the epoxy resin a comprises a non-bisphenol a type epoxy resin.
2. The powder coating composition of claim 1, wherein the first component has a gel time of no more than 120 seconds at 130 ℃.
3. The powder coating composition of claim 1 or 2, wherein the second component has a gel time of at least 300 seconds at 130 ℃.
4. The powder coating composition of any one of claims 1-3, wherein the epoxy resin A has an epoxy equivalent weight of no more than 300 g/eq.
5. The powder coating composition of any one of claims 1-4, wherein the epoxy resin B has an epoxy equivalent weight of at least 500 g/eq.
6. The powder coating composition of any one of claims 1-5, wherein the epoxy resin B comprises a non-bisphenol A type epoxy resin.
7. The powder coating composition of any one of claims 1-6, wherein the weight ratio of polyester resin A to epoxy resin A is from 5 to 1.
8. The powder coating composition of any one of claims 1-7, wherein the weight ratio of polyester resin B to epoxy resin B is from 3 to 1.5.
9. The powder coating composition of any one of claims 1-8, wherein the first component further comprises 0.5 to 2.5wt% of a curing catalyst based on the total weight of all raw materials in the component.
10. The powder coating composition of any one of claims 1-9, wherein the second component further comprises 0 to 0.8wt% of a curing catalyst based on the total weight of all raw materials in the component.
11. The powder coating composition of any one of claims 1-10, wherein the weight ratio of the first component and the second component is 5.
12. The powder coating composition of any one of claims 1-11, wherein the BPA content in the coating composition is <0.1wt%.
13. The powder coating composition of any one of claims 1-12, wherein the powder coating is curable at 120-140 ℃ for 3-5 min under infrared heat curing.
14. The powder coating composition of any one of claims 1-13, wherein the powder coating composition is useful for MDF substrates.
15. The powder coating composition of any one of claims 1-14, wherein a coating formed from the powder coating composition has a gloss value at 60 ° of no more than 40%.
16. A coated substrate comprising a substrate and the dry mix powder coating composition of any one of claims 1-15 coated on at least a portion of the substrate.
17. The coated substrate of claim 16, wherein the substrate comprises MDF.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211533476.2A CN115838563A (en) | 2022-12-01 | 2022-12-01 | Dry-mix powder coating composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211533476.2A CN115838563A (en) | 2022-12-01 | 2022-12-01 | Dry-mix powder coating composition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115838563A true CN115838563A (en) | 2023-03-24 |
Family
ID=85577861
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211533476.2A Pending CN115838563A (en) | 2022-12-01 | 2022-12-01 | Dry-mix powder coating composition |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115838563A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103415545A (en) * | 2011-02-14 | 2013-11-27 | 佐敦粉末涂料（N）公司 | Powder coating |
| CN107304326A (en) * | 2016-04-25 | 2017-10-31 | 江门市东健粉末涂装科技有限公司 | Powdery paints and preparation method thereof and the application in wood surface spraying |
| CN109321094A (en) * | 2018-09-28 | 2019-02-12 | 上海国丽粉体涂料有限公司 | A kind of powdery paints and application thereof |
| CN110804377A (en) * | 2019-11-28 | 2020-02-18 | 老虎表面技术新材料（苏州）有限公司 | Multi-coating combined system of low-temperature fast curing powder coating and coating method and coating thereof |
| CN110922856A (en) * | 2019-11-29 | 2020-03-27 | 老虎表面技术新材料（清远）有限公司 | Powder coating with ultrahigh weather-resistant extinction effect |
| CN111892859A (en) * | 2020-07-22 | 2020-11-06 | 赣州市博品家具有限公司 | Anti-yellowing medium-density fiberboard low-temperature curing powder coating |
| US20220025207A1 (en) * | 2018-10-29 | 2022-01-27 | Allnex Usa Inc. | Low bake powder coating resins |
-
2022
- 2022-12-01 CN CN202211533476.2A patent/CN115838563A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103415545A (en) * | 2011-02-14 | 2013-11-27 | 佐敦粉末涂料（N）公司 | Powder coating |
| CN107304326A (en) * | 2016-04-25 | 2017-10-31 | 江门市东健粉末涂装科技有限公司 | Powdery paints and preparation method thereof and the application in wood surface spraying |
| CN109321094A (en) * | 2018-09-28 | 2019-02-12 | 上海国丽粉体涂料有限公司 | A kind of powdery paints and application thereof |
| US20220025207A1 (en) * | 2018-10-29 | 2022-01-27 | Allnex Usa Inc. | Low bake powder coating resins |
| CN110804377A (en) * | 2019-11-28 | 2020-02-18 | 老虎表面技术新材料（苏州）有限公司 | Multi-coating combined system of low-temperature fast curing powder coating and coating method and coating thereof |
| CN110922856A (en) * | 2019-11-29 | 2020-03-27 | 老虎表面技术新材料（清远）有限公司 | Powder coating with ultrahigh weather-resistant extinction effect |
| CN111892859A (en) * | 2020-07-22 | 2020-11-06 | 赣州市博品家具有限公司 | Anti-yellowing medium-density fiberboard low-temperature curing powder coating |
Non-Patent Citations (1)
| Title |
|---|
| 熊言林: "熊言林中学化学教育研究论集", 安徽师范大学出版社, pages: 36 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101341219A (en) | Powder coating compostion providing low gloss | |
| KR20180136495A (en) | 2-component epoxy resin paint | |
| CN114316752B (en) | Powder coating composition with stable pearlescent texture, preparation method and coating thereof | |
| CN110003763A (en) | Bi-component aqueous epoxy lacquer type organic coating | |
| JPH06293867A (en) | Matte powdery coating composition, method for coating and film made therefrom | |
| JP3484546B2 (en) | Powder coating composition | |
| CN110256938B (en) | Two-component water-based epoxy resin primer | |
| KR101818348B1 (en) | high-gloss high-leveling powder coating composition | |
| KR101965484B1 (en) | Coating composition | |
| CN115838563A (en) | Dry-mix powder coating composition | |
| DE60212780T2 (en) | Powder coating composition, process for its curing and articles derived therefrom | |
| CN112341912A (en) | Powder coating and preparation method and application thereof | |
| CN111566174A (en) | Powder coating composition | |
| KR101278443B1 (en) | Thermosetting urethane powder coating composition comprising crystalline polyester resin with excellent low temperature cure ability | |
| AU2006331758B2 (en) | Powder coating composition suitable for thermo-sensitive substrates | |
| JP2000109728A (en) | Powder coating composition capable of being cured at wide baking temperature range and its coating application | |
| CN114163905B (en) | Powder coating composition and coating thereof | |
| CN114085363B (en) | Polyester resin for high-filling powder coating, preparation method of polyester resin and high-filling powder coating | |
| JPS6228193B2 (en) | ||
| CN117820946A (en) | Powder coating composition and coating thereof | |
| US8158698B2 (en) | Powder coating composition and process of manufacture | |
| JPH021189B2 (en) | ||
| JP2005263939A (en) | Epoxy resin powder coating | |
| CN116716025A (en) | Powder coating composition, curing method and coating thereof | |
| JPS59226065A (en) | Epoxy resin powder coating composition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |