TW202005998A - High-solid content low-viscosity resin composition comprising acrylic copolymer - Google Patents

Abstract

The present invention relates to a high-solid content low-viscosity resin composition comprising an acrylic copolymer, the resin composition having a solid content of at least about 80 wt% on the basis of the weight of the acrylic copolymer and a viscosity of 130,000 mPa.s or less as measured by using a BROOKFIELD viscometer at 25 DEG C, and a main chain of the acrylic copolymer having a suspended poly(oxyalkylene) segment.

Description

High-solid low-viscosity resin composition containing acrylic copolymer and preparation method thereof

The invention relates to a high-solid low-viscosity resin composition, in particular to a resin composition containing an acrylic copolymer. The present invention also relates to a solvent-based coating composition containing the resin composition.

In recent years, with people’s attention to the environment, many countries have enacted environmental laws and requested to further reduce the allowable release of volatile organic compounds (Volatile Organic Compounds, Volatile Organic Compounds, VOC) amount. For example, in China since February 2015, solvent-based coating compositions with VOC content exceeding 420g/L will be levied an additional consumption tax at a rate of up to 4%, which will greatly increase the cost of the coating company. Therefore, the demand for a high-solid low-viscosity resin composition for formulating a solvent-based coating composition having a VOC content of not more than 420 g/L has rapidly increased.

The prior art has disclosed two methods commonly used for preparing high-solid low-viscosity acrylic resin compositions. One method is to use a glycidyl compound. For example, CN102702438 discloses the use of glycidyl tertiary carbonate to prepare high-solid low-viscosity acrylic resin. However, the resulting product can only achieve a solids content of about 70% and still contains a relatively large amount of organic solvent. Another method is by adding hyperbranched modifiers. For example, CN103319666A discloses the use of hyperbranched modifiers to prepare aqueous dispersions of acrylic resins. However, this product is suitable for waterborne coating systems and can only achieve a solids content of 45%. Compared to water-based coating compositions, low VOC content requirements are more difficult to achieve for solvent-based coating compositions.

In addition, a variety of high-solid low-viscosity acrylic resin products have been disclosed, such as 854BA80 from Arkema, Setalux 1753 from Niupeisi resin, and A-870 from Bayer. However, these products still cannot meet the needs of the coating industry.

Therefore, in order to meet the VOC content requirement of less than 420 g/L, the coating industry still needs further improved acrylic resin compositions with high solid content, relatively low viscosity, and suitable for solvent-based coating compositions.

In one aspect, the present invention provides a resin composition comprising an acrylic copolymer, wherein the acrylic copolymer has a suspended poly(oxyalkylene) segment on the main chain, and wherein the resin composition has A solid content of at least about 80% by weight based on the weight of the acrylic copolymer and a viscosity of 130,000 mPa·s or less measured at 25°C using a BROOKFIELD viscometer.

In another aspect, the present invention relates to a method for preparing the above-mentioned acrylic copolymer-containing resin composition, the method comprising: an organic solvent in an amount of not more than 20% by weight relative to the total weight of the resin composition and free In the presence of a base initiator, an ethylenically unsaturated monomer containing a poly(oxyalkylene) segment as the first monomer, an acrylic monomer different from the first monomer, and additional ethylenic The reaction mixture of unsaturated monomers is copolymerized to form the resin composition.

In another aspect, the invention relates to the use of ethylenically unsaturated monomers containing poly(oxyalkylene) fragments for the preparation of the high-solid low-viscosity resin composition according to the invention.

In another aspect, the present invention relates to a solvent-based coating composition having a VOC emission of less than 420 g/L, which includes the resin composition of the present invention.

The inventor of the present invention pioneeredly provided a resin composition containing an acrylic copolymer, wherein the resin composition has a solid content of at least about 80 wt% based on the weight of the acrylic copolymer and at 25°C The viscosity of 130,000 mPa.s or lower was measured using a BROOKFIELD viscometer, and wherein the main chain of the acrylic copolymer had pendant poly(oxyalkylene) segments. At the same time, the resin composition according to the present invention contains, up to 20% by weight of an organic solvent with respect to the total weight of the resin composition.

The inventor of the present invention was surprised to find that during the preparation process of the resin composition of the present invention, through the ethylenically unsaturated monomer containing a poly(oxyalkylene) segment with an acrylic monomer and additional ethylenic unsaturation The copolymerization of the monomers causes the soft poly(oxyalkylene) segments to hang on the backbone of the acrylic copolymer. The presence of the poly(oxyalkylene) segments can be significantly reduced while maintaining the solid content of the resin composition Its viscosity allows the resin composition to formulate a solvent-based coating composition with a VOC emission not exceeding 420 g/L without the need for additional thinners.

The inventor of the present invention was further surprised to find that the high-solid low-viscosity resin composition according to the present invention can be obtained by combining an ethylenically unsaturated monomer containing a poly(oxyalkylene) segment with a very low organic solvent content. The formation of acrylic monomers and additional ethylenically unsaturated monomers by copolymerization was difficult to foresee before the present invention.

The details of one or more embodiments of the invention are set forth in the following description. According to the description and patent application scope, other features, objects and advantages of the present invention will become clear.

definition

As used herein, unless otherwise stated, "a", "this", "at least one" and "one or more" and the use of quantifiers are used interchangeably. Thus, for example, a coating composition containing "a" additive may be interpreted to mean that the coating composition contains "one or more" additives. Unless otherwise stated herein, the use of the singular form herein is also meant to include the plural form.

Where the composition is described as including or containing specific components, it is expected that optional components not covered by the present invention are not excluded from the composition, and that the composition is expected to be composed or composed of the components involved, or In cases where the method is described as including or containing specific process steps, it is expected that the method does not exclude optional process steps not covered by the present invention, and it is expected that the method may consist of or consist of the process steps involved.

When appearing in the scope of this specification and patent application, the terms "comprising" and "including" and variations thereof do not have a limiting meaning.

When referring to the use of "resin composition", the term "high solid content" means that the solid content of the resin composition is at least 80 wt% or higher, wherein the solid content is calculated based on the resin component in the resin composition.

In the context of the present invention, the term "solvent-based coating composition" means that the water content is less than 2 g/L, preferably substantially free, more preferably substantially completely free, and even more preferably completely free of water, using organic solvents as Coating composition for dispersion medium.

When used in relation to "solvent-based coating composition", the term "substantially free" of water means that the solvent-based coating composition of the present invention contains less than 1000 parts per million (ppm) of water; the term "essentially free of" "Water means that the solvent-based coating composition of the present invention contains less than 100 ppm of water; the term "essentially completely free of" water means that the solvent-based coating composition of the present invention contains less than 5 ppm of water; the term "completely free of" water It means that the solvent-based coating composition of the present invention contains less than 20 parts per billion (ppb) of water.

In the context of the present invention, the term "ethylenically unsaturated group" refers to a reactive carbon-carbon double bond unsaturated group having a cis- or trans-configuration, but excluding aromatic unsaturated groups Group, carbon-carbon triple bond, carbon-heteroatom unsaturated group.

In the context of the present invention, the term "reactive mixture" refers to a mixture of reactive monomers, excluding solvents that do not participate in the reaction.

For simplicity, only a few numerical ranges are explicitly disclosed in this article. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or single value between the end points of the range is included in the range. Thus, each point or single numerical value may be combined with any other point or single numerical value as its own lower limit or upper limit or with other lower or upper limits to form an unspecified range.

In the present invention, the numerical range defined by the endpoints includes all numerical values within the range, for example, the range of 1 to 5 covers the numerical values 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, and so on. Moreover, the disclosed numerical range includes all sub-ranges within the wider range, for example, the range of 1 to 5 includes the sub-ranges 1 to 4, 1.5 to 4.5, 1 to 2, and so on.

The terms "preferred" and "preferably" refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not mean that other embodiments are not available, and is not intended to exclude other embodiments from the scope of the invention.

According to a first aspect of the present invention, the present invention provides a resin composition comprising an acrylic copolymer, wherein the resin composition has a solid content of at least about 80% by weight based on the weight of the acrylic copolymer and at 25 The viscosity of 130,000 mPa.s or less was measured using a BROOKFIELD viscometer at ℃, and the acrylic copolymer had a suspended poly(oxyalkylene) segment on the main chain.

The resin composition according to the present invention not only has a high solid content, but also has a very low viscosity, and thus can be used to formulate a solvent-based coating composition without introducing excessive VOC. In one embodiment of the present invention, the resin composition has a solid content of at least about 80 wt% based on the weight of the acrylic copolymer. The inventor was surprised to find that the resin composition of the present invention has a significantly lower viscosity while maintaining a high solid content. In one embodiment of the present invention, the resin composition has a viscosity of 60,000 mPa.s or less, more preferably 10,000 mPa.s or less, measured using a BROOKFIELD viscometer at 25°C.

The resin composition according to the present invention also contains a relatively small amount of organic solvent, for example, containing not more than 20% by weight of organic solvent, preferably not more than 18% by weight of organic solvent relative to the total weight of the resin composition.

The resin composition with the above characteristics does not need to add a large amount of solvent for dilution when it is used to formulate a solvent-based coating composition, or even does not need to add a solvent as a diluent at all, so it can be formulated to form a VOC emission not exceeding 420g/L Solvent-based coating composition.

In the resin composition according to the present invention, the acrylic copolymer has a suspended poly(oxyalkylene) segment on the skeleton. In an embodiment of the present invention, based on the weight of the acrylic copolymer, the poly(oxyalkylene) segment is present in an amount of 15-60 wt%, preferably in an amount of 20-50 wt%. The poly(oxyalkylene) segment is suspended on the skeleton of the acrylic copolymer so that the resin composition containing the acrylic copolymer can show a significantly reduced viscosity while maintaining a high solid content.

According to the invention, the poly(oxyalkylene) is selected from poly(oxyethylene) segments, poly(oxypropylene) segments, poly(oxybutylene) segments, poly(oxypentylene) segments and Any combination of poly(oxyalkylene) fragments. Preferably, the poly(oxyalkylene) segment is selected from the group consisting of poly(oxyethylene) segment, poly(oxypropylene) segment, and combinations thereof.

其中A為

並且R¹、R²和R³相互獨立地選自-CH₃、H或

，且R¹、R²和R³中的至多一個為，

其中X為-(CH₂)_a-、-CO-或-(CH₂)_a-CO-，其中a為1-6；R⁴為-CH₃或H；b和c相互獨立地為0至500且b和c不同時為0。 According to the present invention, the poly(oxyalkylene) segment is derived from an ethylenically unsaturated monomer containing a poly(oxyalkylene) segment having the following formula I, also known as an ethylenically unsaturated group-containing Polyether,

Where A is

And R ¹ , R ² and R ³ are independently selected from -CH ₃ , H or

, And at most one of R ¹ , R ² and R ³ is,

Where X is -(CH ₂ ) _a -, -CO- or -(CH ₂ ) _a -CO-, where a is 1-6; R ⁴ is -CH ₃ or H; b and c are independently 0 to 500 and b and c are not 0 at the same time.

According to the present invention, the polyether represented by the above formula I in which X is -(CH ₂ ) _a -is called an ether polyether, and wherein X is in the upper part of -CO- or -(CH ₂ ) _a -CO- The polyether represented by Formula I is called an ester polyether.

In some embodiments, the ethylenically unsaturated group-containing polyether is an ether-type polyether. Examples of ether type polyethers according to the present invention include allyl polyethers (eg allyl polyoxyethylene ethers, allyl polyoxypropylene polyoxyethylene polyethers), methallyl polyethers, etc. It is commercially available, such as HMP-523B, HMS-239B, HMS-233B, HMP-517B, etc. from Real Madrid, Zhejiang.

In some embodiments, the ethylenically unsaturated group-containing polyether is an ester-type polyether. Examples of the ester type polyether according to the present invention include propylene oxypolyoxyethylene ether, propylene oxypolyoxypropylene ether, methacryl oxypolyoxyethylene ether, methacryl oxypolyoxypropylene ether , These are commercially available.

In some embodiments of the present invention, the ethylenically unsaturated group-containing polyether has a number average molecular weight between 100-10000, more preferably between 200-6000, and even more preferably between 300-2000 . The number average molecular weight can be measured using GPC.

According to the present invention, the resin composition is made of components including: 15-60 wt% of ethylenically unsaturated monomers containing poly(oxyalkylene) segments relative to the total weight of the reaction mixture ( Hereinafter referred to as "first monomer"), relative to the total weight of the reaction mixture, 35-60 wt% of acrylic monomers different from the first monomer, relative to the total weight of the reaction mixture, an additional 5-30 wt% Of ethylenically unsaturated monomers.

The inventors of the present invention have surprisingly found that the resin composition according to the present invention can be formed by making the first monomer different from the first monomer in the presence of a radical initiator and a very small amount of organic solvent The acrylic monomer and the additional ethylenically unsaturated monomer were copolymerized without gelation. Preferably, the organic solvent is present in an amount of 15-20 wt%, preferably 15-18 wt%, more preferably 15-17 wt% relative to the total weight of the resin composition. The resin composition thus obtained not only has a high solids content but also has a significantly lower viscosity, for example, the resin composition has a solids content of at least about 80% by weight based on the weight of the acrylic copolymer and a BROOKFIELD viscosity at 25°C The meter measures a viscosity of 130,000 mPa.s or lower.

In the preparation of the resin composition according to the present invention, the first monomer is necessary. As described above, the inventors were surprised to find that by introducing the first monomer, ie, an ethylenically unsaturated monomer containing poly(oxyalkylene) segments during the preparation of the resin composition, the The high solid content also significantly reduces its viscosity, allowing the resin composition to formulate a solvent-based coating composition with a VOC emission of no more than 420 g/L without the need for additional thinners.

Therefore, the present invention also relates to the use of the above-mentioned poly(oxyalkylene) segment-containing ethylenically unsaturated monomer for preparing the high-solid low-viscosity resin composition containing the acrylic copolymer according to the present invention.

Preferably, the components used to prepare the resin composition of the present invention comprise, relative to the total weight of the reaction mixture, 15-55 wt% of ethylenically unsaturated monomers containing poly(oxyalkylene) segments, preferably 20-50% by weight of poly(oxyalkylene) segment-containing ethylenically unsaturated monomers, more preferably 20-40% by weight of poly(oxyalkylene) segment-containing ethylenically unsaturated monomers.

In the preparation of the resin composition according to the present invention, an acrylic monomer different from the first monomer may also be included. The presence of this monomer can be used to provide the mechanical strength and film-forming properties of the resulting resin composition. In the embodiment of the present invention, as examples of acrylic monomers, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, ( 2-ethylhexyl meth)acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-(acetyl acetyl oxy) methacrylate Ethyl acetate, diacetone acrylamide, hydroxymethyl (meth) acrylamide, acrylonitrile, allyl methacrylate or mixtures thereof.

In some embodiments, the acrylic monomer may include at least one active hydrogen-containing monomer so that the final resin composition obtained has active hydrogen functionality, such as those derived from hydroxyl, amine, and acid functionality . Preferably, based on the total weight of the reaction mixture, the active hydrogen-containing acrylic monomer is present in an amount of 5-20 wt%, preferably in an amount of 10-15 wt%. The presence of this active hydrogen-containing acrylic monomer ensures that the resulting resin composition containing an acrylic copolymer according to the present invention can be used to formulate a two-component solvent-based coating composition.

Preferably, the components used to prepare the resin composition of the present invention comprise, relative to the total weight of the reaction mixture, present in an amount of at least 35% by weight, preferably in an amount of at least 40% by weight, more preferably in an amount of at least 45% by weight , Most preferably an acrylic monomer present in an amount of at least 50 wt%. More preferably, based on the total weight of the reaction mixture, the acrylic monomer is present in an amount of at most 60 wt%, more preferably in an amount of at most 56 wt%.

In the preparation of the resin composition according to the invention, additional ethylenically unsaturated monomers may also be included. This monomer can be used to adjust the mechanical strength of the resulting resin composition. In an embodiment of the invention, the additional ethylenically unsaturated monomer is selected from styrene, vinyl toluene, vinyl acetate or mixtures thereof.

Preferably, the components used to prepare the resin composition of the present invention contain, in an amount of 15-30% by weight relative to the total weight of the reaction mixture, additional ethylenically unsaturated monomers.

In the preparation of the resin composition according to the present invention, an organic solvent may be included to adjust the viscosity of the system. Suitable solvents include aromatic hydrocarbons such as benzene, toluene and xylene; alcohols such as ethanol, isopropanol, n-butanol, tert-butanol and ethylhexanol; esters such as ethyl acetate, propyl acetate and butyl acetate Ester, isobutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, etc. Other suitable solvents include ketones such as methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, etc.; glycols such as propylene glycol and diethyl glycol; glycol ethers such as propylene glycol monomethyl ether 、Ethylene glycol monomethyl ether. Of course, various mixtures of solvents can be used. According to the present invention, the amount of organic solvent can be very low, such as less than 20wt%, less than 19wt%, less than 18wt%, less than 17wt%, less than 15wt%, without affecting the formation of acrylic copolymers, Where the amount is calculated relative to the total weight of the resin composition, this was unimaginable before the present invention. As described in CN1201809, the reduction in the amount of solvent used during the preparation of conventional resin compositions is actually limited, usually not less than 20 wt% of the total weight of the reaction mixture. If you try to lower the solvent again, the resulting resin composition becomes too viscous and even gels, making it impossible to formulate the coating composition.

Therefore, the present invention also relates to a method for preparing a resin composition containing an acrylic copolymer according to the present invention, the method comprising: an amount of not more than 20% by weight of organic compound relative to the total weight of the resin composition In the presence of a solvent and a free radical initiator, an ethylenically unsaturated monomer containing a poly(oxyalkylene) segment as the first monomer, an acrylic monomer different from the first monomer, and additional The reaction mixture of the ethylenically unsaturated monomer is copolymerized, thereby forming the resin composition.

The appropriate conditions for the above reaction depend on various factors, including the types of ethylenically unsaturated monomers and acrylic monomers containing poly(oxyalkylene) segments, the presence or absence of solvents, and the types of initiators, etc. These can be Those skilled in the art will determine it empirically. Without wishing to be bound by any theory, the inventor provides the following explanation so that the present invention can be better understood.

In the resin composition containing an acrylic copolymer according to the present invention, an appropriate amount of poly(oxyalkylene) segments are suspended from the main chain of the acrylic copolymer. Due to the flexibility of the poly(oxyalkylene) segments, Helps to improve the molecular activity of acrylic copolymers, so as to achieve the purpose of significantly reducing viscosity. In addition, the non-polar side groups suspended on the main chain weaken the force between the molecular chains and further improve the solubility of the acrylic copolymer in the solvent, thereby making the acrylic copolymer-containing resin composition according to the present invention The preparation can be carried out in the presence of very small amounts of organic solvents without gelation or hardening.

Due to its high solids content and low viscosity, the resin composition containing acrylic copolymers according to the present invention is suitable for formulating low-VOC solvent-based coating compositions, for example, solvent-based coating compositions with VOC emissions not exceeding 420 g/L can be formulated Thing.

Accordingly, another aspect of the present invention provides a solvent-based coating composition with a VOC emission of no more than 420 g/L, which includes the acrylic copolymer-containing resin composition disclosed herein and optional additional additives. Specifically, the solvent-based coating composition includes, with respect to the total weight of the coating composition, (i) 30 to 99.5 parts by weight of a resin composition containing a polyether-modified polyester; (ii) 0.5 to 70 parts by weight of optional additional additives.

According to the present invention, the content of the acrylic copolymer-containing resin composition described herein is in the range of 30 to 99.5 parts by weight, preferably in the range of 40 to 90 parts by weight relative to the total weight of the solvent-based coating composition Within, it is more preferably in the range of 50 to 85 parts by weight.

If desired, the coating composition of the present invention may optionally include other additives that do not adversely affect the coating composition or the cured coating obtained therefrom. Suitable additives include, for example, will improve the processability or manufacturing performance of the composition, enhance the aesthetics of the composition, or improve the specific functional properties or characteristics of the coating composition or the resulting cured composition (such as adhesion to the substrate) Those reagents. Additives that may be included are solvents, carriers, additional polymers, pigments, metal powders or pastes, fillers, anti-migration aids, antibacterial agents, extenders, lubricants, defoamers, biocides, plasticizers Agents, thickeners, colorants, waxes, antioxidants, corrosion inhibitors, flow control agents, thixotropic agents, dispersants, UV stabilizers, or combinations thereof. The content of each optional ingredient is sufficient for its intended purpose, but preferably, such content does not adversely affect the coating composition or the cured coating obtained therefrom. Examples of additional additives suitable for the coating composition include plasticizers, pigments, fillers, thickeners, defoamers, wetting agents, dispersants, solvents, or combinations thereof.

The content of the additional additive is in the range of 0.5 to 70 parts by weight relative to the total weight of the solvent-based coating composition, or more preferably in the range of 1 to 50 parts by weight.

In addition to formulating a solvent-based coating composition with the above VOC emission not exceeding 420 g/L, the resin composition according to the present invention can also be used to formulate a two-component solvent-based coating composition. Therefore, another aspect of the present invention includes a two-component solvent-based coating composition with a VOC emission not exceeding 420 g/L, which includes a film-forming resin composition a), the film-forming resin composition comprising the above-disclosed herein The resin composition containing acrylic copolymer and optional additional additives; and crosslinking agent b).

An example of a suitable crosslinker component is polyisocyanate.

Suitable polyisocyanate crosslinking agents include aliphatic polyisocyanates, aromatic polyisocyanates, or any combination thereof. The term "aliphatic polyisocyanate" as used herein refers to a polyisocyanate compound in which an isocyanate group is directly attached to an aliphatic chain or ring. The term "aromatic polyisocyanate" as used herein refers to a polyisocyanate compound in which an isocyanate group is directly attached to an aromatic ring.

Suitable isocyanates for use in the present invention include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, deca methylene diisocyanate, butylene-1,2-diisocyanate, butylene-1,3-diisocyanate, ethylene diisocyanate; cycloaliphatic diisocyanates, such as cyclohexylene diisocyanate, 4,4 '- Methylene bis (cyclohexyl isocyanate), 2,2,4-trimethylhexamethyl diisocyanate, dimer acid diisocyanate, 3-isocyanatomethyl-3,5,5-trimethyl Cyclohexyl isocyanate; and aromatic diisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, chlorinated toluene diisocyanate, m-phenylene diisocyanate, m-phenylene diisocyanate chloride, o Phenylene diisocyanate, brominated m-phenylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5 - diisocyanate, naphthylene-2,7-diisocyanate, 4 ', 4-biphenylene diisocyanate, 3,3' - dichloro - 4,4 '- biphenylene diisocyanate, 3,3 '- dimethyl - 4,4' - biphenylene diisocyanate, 3,3 '- dimethoxy -4,4' - biphenylene diisocyanate, 2,2 ', 5,5' - tetramethyl-4,4 '- biphenylene diisocyanate, 2-nitro-4,4' - biphenylene diisocyanate, 3,3 '- diphenyl - 4,4' - biphenylene yl diisocyanate, 4,4 '- methylene - bis (phenyl isocyanate), 4,4' - methylene - bis (2-methylphenyl isocyanate), 4,4 '- isopropylidene - bis ( Phenyl isocyanate) and fluorene diisocyanate; triisocyanates such as hexamethylene diisocyanate biuret, 4,4 ' ,4 " -triphenylmethane triisocyanate and toluene-2,4,6-triisocyanate; iso Cyanurates, such as those based on hexamethylene diisocyanate or 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate; tetraisocyanates and mixtures thereof.

Particularly suitable isocyanates are polyfunctional aliphatic isocyanates based on hexamethylene diisocyanate (HDI). Some commercially available HDIs include Tolonate® HDT or Tolonate® HDT LV, available from Rhone-Poulenc Inc. (Organic Chemistry Branch), Monmouth Junction, NJ, or Desmodur® N-3300 or Desmodur® N-3390 isocyanate, available from Bayer AG, Pittsburgh, PA.

According to the invention, the solvent-based coating composition can be applied by conventional application methods known to those of ordinary skill in the art. The coating methods include dip coating, spin coating, spray coating, curtain coating, brush coating, roll coating, and other coating methods known in the art.

Conventional coating techniques can be used to apply low VOC solvent-based coating compositions to various substrates. Examples of suitable substrates include wood, cement, cement fiberboard, wood-plastic composites, tiles, metal, plastic, glass, and fiberglass.

testing method

Unless otherwise noted, the following test methods are used in the following examples.

Solid content

According to GB/T1725-2007 standard for determination.

Viscosity

Measured according to ASTM D 2196 (Rheological properties of non-Newtonian materials measured by a Brookfield viscometer).

Gloss

This test measures the gloss of the cured coating. The gloss was evaluated according to ASTM D523.

Pencil hardness

This test is used to measure the hardness of cured coatings. ASTM D3363 was used to evaluate pencil hardness. The data is reported as the last time the pencil hardness was successfully tested before the coating cracked. Thus, for example, if the coating does not break when tested with a 2H pencil, but breaks when tested with a 3H pencil, the coating is reported to have a pencil hardness of 2H.

Adhesion

An adhesion test was conducted to assess whether the coating adhered to the coated substrate. The root directory of the adhesion test is conducted in accordance with ASTM D 3359-Test Method B. Adhesion is usually divided into 0-5B grades, where 5B represents the optimal adhesion.

Examples

Hereinafter, the disclosure of the present invention will be described more specifically by examples. These embodiments are for illustrative purposes only, and cannot be construed as limiting the scope of protection of the present invention, because it is obvious to those skilled in the art that various modifications and changes can be made within the scope of the present disclosure.

Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available and can be used directly without further processing.

material

The materials used are listed in Table 1 below.

Preparation of resin composition containing acrylic copolymer

A resin composition containing an acrylic copolymer was prepared according to the ingredients shown in Table 2 below. The specific steps are: (1) Weigh each raw material; (2) Fill Part 3 with a nitrogen purge into the flask and then heat to 140°C; (3) Keep the reaction temperature of the flask at 140°C Add Part 1 and Part 2 to the reaction flask in order within 3.5 hours; (4) After the monomer feed is completed, hold at 140°C for 1 hour; (5) Add Part 4 to the reaction flask within 1 hour, and then Hold at 140°C for 2 hours; (6) Cool to room temperature to obtain a resin composition containing an acrylic copolymer.

The solid content and viscosity of the obtained resin composition were measured, and the results are shown in Table 3 below:

It can be seen from the above results that in the preparation of acrylic copolymers, the introduction of ethylenically unsaturated monomers containing poly(oxyalkylene) segments can form a high-solid low-viscosity resin composition containing acrylic copolymers, which The resin composition has a solid content of at least about 80% by weight based on the weight of the acrylic copolymer and a viscosity of 130,000 mPa·s or less measured at 25°C using a BROOKFIELD viscometer. In contrast, acrylic copolymers prepared using monomer mixtures that do not contain ethylenically unsaturated monomers with poly(oxyalkylene) segments are hard solids and cannot be used to formulate solvent-based coating compositions at all.

Preparation of low VOC solvent-based coating composition

The low VOC solvent-based coating composition was prepared according to the ratio in Table 4 below, and pigments, fillers, thickeners, defoamers, wetting and dispersing agents, and solvents were added to the Resin composition, thereby forming a solvent-based coating composition. Then, the solvent-based coating composition thus formed was applied to a bare steel plate with a coating film applicator, thus obtaining a coating with a dry film thickness of 0.05 mm (2±0.1 mil). The coating was cured at room temperature for two weeks, and then the measurements given in the table below were obtained

From the above results, it can be seen that the resin composition containing the acrylic copolymer according to the present invention can be directly used to formulate a low VOC (VOC emission below 420g/L) solvent-based coating composition, and the coating formed therefrom The layer has good coating properties.

Although the present invention is described with reference to a large number of embodiments and examples, those of ordinary skill in the art can recognize that other embodiments can be designed based on the disclosure of the present invention, without departing from the scope and spirit of the present invention.

Claims (19)

A resin composition containing an acrylic copolymer, wherein the main chain of the acrylic copolymer has a suspended poly(oxyalkylene) segment, and wherein the resin composition has a composition based on the acrylic copolymer A solid content of at least 80% by weight and a viscosity of 130,000 mPa·s or less at 25°C using a BROOKFIELD viscometer. The resin composition according to item 1 of the patent application range, wherein the resin composition has a solid content of at least 81 wt% based on the weight of the acrylic copolymer. The resin composition as described in item 1 of the patent application range, wherein the resin composition has a viscosity of 60,000 mPa.s or lower, preferably 10,000 mPa.s or lower, measured at 25° C. using a BROOKFIELD viscometer. The resin composition according to item 1 of the patent application scope, wherein the poly(oxyalkylene) segment is selected from a poly(oxyethylene) segment, a poly(oxypropylene) segment, and a poly(oxybutylene) Group) segment, poly(oxypentylene) segment and any combination thereof, preferably selected from poly(oxyethylene) segment, poly(oxypropylene) segment or a combination thereof. The resin composition as described in item 1 of the patent application range, wherein the poly(oxyalkylene) segment is present in an amount of 15-60 wt% based on the weight of the acrylic copolymer, preferably 20-50 wt % Of the amount exists. The resin composition according to any one of items 1 to 5 of the patent application range, wherein the poly(oxyalkylene) segment is derived from the poly(oxyalkylene) segment-containing ethylenic fragment of the following formula Saturated monomer,

In the above formula, A is

And R ¹ , R ² and R ³ are independently selected from H, -CH ₃ or

, And at least one of R ¹ , R ² and R ³ is

, Where X is -(CH ₂ ) _a -, -CO- or -(CH ₂ ) _a -CO-, where a is 1-6; R ⁴ is -CH ₃ or H; b and c are independently 0 To 500 and b and c are not 0 at the same time. The resin composition according to any one of items 1 to 5 of the patent application range, wherein the resin composition contains up to 20% by weight of a solvent based on the total weight of the resin composition. The resin composition according to any one of items 1 to 5 of the patent application range, wherein the resin composition contains up to 15% by weight of a solvent based on the total weight of the resin composition. A method for preparing a resin composition containing an acrylic copolymer, wherein the skeleton of the acrylic copolymer has a suspended poly(oxyalkylene) segment, and wherein the resin composition has a base based on the acrylic The copolymer has a solid content of at least 80 wt% and a viscosity of 130,000 mPa.s or less measured at 25°C using a BROOKFIELD viscometer. The method includes: using an amount not exceeding 20 wt relative to the total weight of the resin composition % In the presence of a solvent and a free radical initiator, the first monomer contains an ethylenically unsaturated monomer containing a poly(oxyalkylene) segment, and an acrylic monomer different from the first monomer The reaction mixture with the additional ethylenically unsaturated monomer is copolymerized to form the resin composition. The method according to item 9 of the patent application scope, wherein the poly(oxyalkylene) segment is selected from poly(oxyethylene) segment, poly(oxypropylene) segment, poly(oxybutylene) The fragments, poly(oxypentylene) fragments and any combination thereof are preferably selected from poly(oxyethylene) fragments, poly(oxypropylene) fragments or combinations thereof. The method according to item 9 of the patent application scope, wherein the poly(oxyalkylene) segment-containing ethylenically unsaturated monomer has a structure represented by the following formula I,

In the above formula (I), A is

And R ¹ , R ² and R ³ are independently selected from -CH ₃ , H or

, And at least one of R ¹ , R ² and R ³ is

, Where X is -(CH ₂ ) _a -, -CO- or -(CH ₂ ) _a -CO-, where a is 1-6; R ⁴ is -CH ₃ or H; b and c are independently 0 To 500 and b and c are not 0 at the same time. The method according to item 9 of the patent application scope, wherein the number average molecular weight of the poly(oxyalkylene) segment-containing ethylenically unsaturated monomer is between 100-10000, preferably between 200-6000 Time, more preferably between 300-2000. The method according to any one of items 9-12 in the patent application range, wherein the acrylic monomers different from the first monomer include (meth)acrylic acid, methyl (meth)acrylate, ( Ethyl methacrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, (meth)acrylic acid Hydroxypropyl ester, 2-(acetylacetoacetoxy)ethyl methacrylate, diacetone acrylamide, hydroxymethyl (meth)acrylamide, acrylonitrile, or a mixture thereof. The method according to any one of items 9-12 in the patent application range, wherein the additional ethylenically unsaturated monomer is selected from styrene, vinyl toluene or a mixture thereof. The method according to any one of items 9-12 in the patent application range, wherein the reaction mixture comprises, relative to the total weight of the reaction mixture, 15-60 wt% of the first monomer; 35- 60 wt% of the acrylic monomer different from the first monomer; and 5-30 wt% of the additional ethylenically unsaturated monomer. The method according to any one of items 9-12 in the patent application range, wherein the resin composition has a solid content of at least 81 wt% based on the weight of the acrylic copolymer. The method according to any one of items 9-12 in the patent application range, wherein the resin composition has a viscosity of 60,000 mPa.s or less measured at 25° C. using a BROOKFIELD viscometer, preferably 10,000 mPa.s or Lower viscosity. The method as described in item 9 of the patent application range, wherein, based on the total weight of the resin composition, a solvent of up to 15% by weight is used. A solvent-based coating composition with a VOC emission of less than 420 g/L, which contains the resin composition described in any one of the patent application items 1 to 8 or any one of the patent application items 9 to 18 The obtained resin composition is prepared by the method described above.