274 results about "Hydroxyl value" patented technology

The invention discloses a deep eutectic solvent / bimetal organic framework co-catalyzed straw polyol as well as a preparation method and application thereof, the straw polyol is prepared by the following method: uniformly mixing straw powder, small molecular alcohol, an acid catalyst and a deep eutectic solvent in a nitrogen atmosphere, and reacting to obtain a reaction product; and adding a bimetal organic framework catalyst into the reaction product, and reacting to obtain the straw polyol. A green, natural and pollution-free eutectic solvent catalytic liquefaction technology is adopted, lignin and hemicellulose can be dissolved, the cross-linking effect between lignin and hemicellulose and cellulose is reduced, the crystalline structure of cellulose can be destroyed, the available surface area is increased, the contact with a liquefying agent is enhanced, the conversion efficiency is improved, and the residue rate is reduced; the bimetallic organic framework catalyst is added in the middle and later periods of the reaction, aldehydes, ketones and acid and ester substances can be reduced and upgraded into alcohols, the hydroxyl value of the liquefied polyol is greatly increased, and the film-forming crosslinking degree is improved.

The invention relates to the technical field of pouring sealant coatings, in particular to a two-component polyurethane circuit board pouring sealant and a preparation method thereof. Comprising a component A and a component B. The component A comprises liquefied MDI, a phosphate flame retardant and a plasticizer. The component B comprises a hydroxyl acrylate oligomer, bio-based polyol, a defoaming agent and a catalyst, the viscosity of the hydroxyl acrylate oligomer at the temperature of 25 DEG C is 8000-15000 mPa.s, and the hydroxyl value of the hydroxyl acrylate oligomer is 100-150 mgKOH / g. The viscosity of the hydroxyl acrylate oligomer at 25 DEG C is limited to be 8000-12000 mPa.s, and the hydroxyl value is 100-140 mgKOH / g, so that the mechanical properties and aging resistance of the pouring sealant can be improved at the same time.

The invention belongs to the technical field of polyester polyol, and particularly relates to high-functionality low-viscosity polyester polyol and a step-by-step synthesis method thereof. Comprising the following steps: (1) adding dihydric alcohol, dicarboxylic acid, a catalyst and an antioxidant into a reaction kettle, heating and vacuumizing, and carrying out esterification and ester exchange reaction to prepare a polyester polyol intermediate; and (2) cooling the polyester polyol intermediate prepared in the step (1), adding polyol into the reaction kettle, and continuously carrying out ester exchange reaction to obtain the high-functionality low-viscosity polyester polyol after the reaction is finished. According to the step-by-step synthesis method, the problems that in the prior art, high-functionality polyester polyol is large in viscosity and low-viscosity products are difficult to prepare are solved, the viscosity of the high-functionality polyester polyol can be effectively reduced under the same raw material system and hydroxyl value conditions through specific raw material selection and process control, and the method is simple in process and easy to implement. The industrial production is convenient.

The invention relates to a silicon-containing polycarbonate diol, a polyurethane elastomer material and a preparation method thereof, and belongs to the technical field of organic materials. The glass transition temperature (Tg) of the silicon-containing polycarbonate diol ranges from 40 DEG C to 60 DEG C below zero, the hydroxyl value ranges from 60.4 mgKOH / g to 67.9 mgKOH / g, the product purity is high, the product purity is 98 or above, and the number-average molecular weight of the polycarbonate diol ranges from 1900 Da to 2200 Da. The low-temperature flexibility of the polycarbonate diol is effectively improved, and the use temperature range of the polycarbonate diol is widened. The polycarbonate diol disclosed by the invention is stable in hydroxyl value and narrow in molecular weight distribution; the product quality is good, and subsequent application is facilitated. The polycarbonate diol is short in preparation time, high in efficiency, simple in technological process, mild in technological condition and suitable for large-scale industrial production. The raw materials are low in cost.

The invention belongs to the technical field of preparation and surface protection of polyurethane coatings, and particularly relates to weather-resistant polyurethane and a preparation method thereof. The coating provided by the invention is composed of a component A and a component B according to a weight ratio of 1: (0.2-0.4). The component A is prepared from water-based fluorine-containing hydroxy acrylic dispersion resin with a high hydroxyl value, GMA (glycidyl methacrylate) grafted modified water-based acrylic dispersion resin, a benzotriazole ultraviolet light absorber, a light hindered amine stabilizer, rutile titanium dioxide, wet sericite powder, nano zinc oxide and auxiliaries; and the component B comprises an aliphatic isocyanate curing agent and propylene glycol diacetate. By constructing a quadruple synergistic weather-resistant mechanism of ultraviolet absorption, free radical capture, physical shielding and structural densification, the weather resistance and corrosion resistance of the coating are remarkably improved while the coating keeps excellent adhesive force (0-1 level) and hardness (2H-3H), the color change delta E is smaller than or equal to 1.8 after artificial accelerated aging for 1000 hours, the gloss loss rate is smaller than or equal to 23%, and the weather resistance and corrosion resistance of the coating are greatly improved. And the corrosion spreading width of a 600-hour salt spray test lineation is less than or equal to 2.3 mm.

The present invention discloses a method for measuring the hydroxyl value of a polyether polyol using nuclear magnetic resonance phosphorus spectroscopy, comprising: 1) adding a polyether polyol sample to be tested and an internal standard bisphenol A to a deuterated reagent and dissolving them by ultrasonication; 2) adding a phosphorus oxychloride compound and an acid binding agent to the mixture and allowing them to react fully to obtain corresponding different derivatized phosphorus-containing products; 3) performing a phosphorus spectroscopy test in a nuclear magnetic resonance analyzer to obtain nuclear magnetic resonance phosphorus spectroscopy data, processing and analyzing the data, integrating the nuclear magnetic resonance characteristic peak areas of the phosphorus-containing products after derivatization of the polyether polyol sample and the internal standard bisphenol A, and normalizing them to 100%, and calculating the hydroxyl value of the sample to be tested based on the molar ratio relationship between the products. The hydroxyl value result obtained by the present method has a relative deviation of less than 5% from the result obtained by the phthalic anhydride acylation method in the national standard GB / T 12008.3-2009, and the two results are close and highly accurate. The analytical testing method of the present invention is simple, has low pollution, and is short in time.

The present invention belongs to the technical field of the preparation of modified isocyanates, and particularly relates to a modified isocyanate, a preparation method thereof and an application; the modified isocyanate comprises: 70-94 parts of an organic isocyanate; 6-30 parts of polyether polyol i; the polyether polyol i is a polyether polyol randomly copolymerized with EO / PO monomers and capped with EO, or a polyether polyol block copolymerized with PO monomers and capped with EO, or a mixture of the two; the average molecular weight of the polyether polyol i is 2000-10000, the functionality is 2-4, the EO content is 5-29 wt%, the hydroxyl value is 20-80 mgKOH / g, and the primary hydroxyl group content is greater than or equal to 70%. The modified isocyanate of the present invention has good storage stability, and the slow-rebound polyurethane foam prepared therefrom has fine open cells, and has the advantages of high tolerance, good tear performance, and good sound absorption and sound insulation effects.

A polishing liquid containing: abrasive grains; an additive; and water, in which the additive includes (A1) a polyglycerol having a weight average molecular weight of 350 to 2800 and (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded. A polishing liquid containing: abrasive grains; an additive; and water, in which the additive includes (A2) a polyglycerol having a hydroxyl value of 800 to 1000 mgKOH / g and (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

The purpose of the present invention is to provide a method for forming a multilayer coating film which makes it possible to form a multilayer coating film having excellent metallic mottling resistance. The method for forming a multilayer coating film comprises: (1) a step for applying a first aqueous coating material (P1) on an object to be coated to form a first coating film; (2) a step for applying a second aqueous colored coating material (P2) on the first coating film to form a second colored coating film that contains a binder component (AP2) and lustrous pigment (BP2); (3) a step for applying a clear-coat coating material (P3) on the second colored coating film to form a clear-coat coating film; and (4) a step for heating a multilayer coating film that includes the first coating film, the second colored coating film, and the clear-coat coating film so as to cure the multilayer coating film all at once. The first aqueous coating material (P1) contains a compound (A) containing a hydroxyl group and an acid group and that has an acid value of from 50 to 150 mg KOH / g, a hydroxyl value of from 100 to 300 mg KOH / g, and a weight-average molecular weight of from 500 to 8000, a film-forming resin (B), and a crosslinking agent (C).

The invention provides a method for detecting the hydroxyl value of a polyether material. The method comprises the following steps: (1) constructing a standard quantitative system of a derivatization reagent; (2) fully reacting a to-be-detected polyether material with the excessive derivatization reagent; (3) testing the peak area of the unreacted derivatization reagent by adopting chromatography; (4) comparing with a standard quantitative system of the derivatization reagent, and calculating the content of the unreacted derivatization reagent; and (5) calculating the consumption of the derivatization reagent in the step (2) by using the calculated content of the unreacted derivatization reagent, thereby calculating the hydroxyl value of the polyether material according to the stoichiometric relationship. Wherein the derivatization reagent comprises at least one hydroxyl esterifying agent selected from the following groups: phthalic anhydride, acetic anhydride and benzoyl chloride.

The invention belongs to the technical field of polyether synthesis, and discloses a synthesis method of dimethyl-terminated polyether. The synthesis method comprises the following steps: mixing methanol polyether with an alkoxide reagent, heating and degassing, then adding an adsorbent and a seed crystal, then adding chloromethane to carry out a curing reaction, and finally carrying out secondary degassing to prepare the dimethyl-terminated polyether, wherein the seed crystal is selected from at least one of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium phosphate and potassium dihydrogen phosphate; the adding amount of the seed crystal is 0.1%-2% of the mass of the methanol polyether. According to the synthesis method provided by the invention, a synthesis process and a refining process are combined, and the total process time can be greatly shortened, the preparation efficiency can be improved and the production cost can be reduced by controlling the adding time of the adsorbent and the crystal and cooperatively using the adsorbent and the crystal; and moreover, the quality of the dimethyl-terminated polyether can be improved, and the prepared dimethyl-terminated polyether finished product is light in color, low in hydroxyl value, low in potassium and sodium ion content and high in termination rate.

High resiliency polyurethane foams are made by reacting a polyisocyanate with a mixture of polyols and water. The polyols include a cell opener. The cell opener is a random copolymer of 60 to 80 wt.-% ethylene oxide and correspondingly 40 to 20 wt.-% propylene oxide having a nominal functionality of 2 to 4 and a hydroxyl number of 25 to 50, wherein 50 to 75% of the hydroxyl groups of polyether polyol are primary hydroxyl groups, which is made using a modified double metal cyanide catalyst.

To provide a curable resin composition for flexible film coating capable of forming a cured film excellent in flexibility and scratch resistance.SOLUTION: The curable resin composition for flexible film coating according to an embodiment contains a urethane (meth)acrylate and a tetrafunctional thiol compound. The urethane (meth)acrylate is a reaction product of a raw material containing: a pentaerythritol (meth)acrylate having a hydroxyl value of 150-240 mg KOH / g; and an aliphatic polyisocyanate.SELECTED DRAWING: None

The invention discloses all-water foaming ultralow-density polyurethane foam and a preparation method thereof. The foam is prepared from the following components in parts by weight: 100 parts of polyether polyol composition, 100 to 150 parts of polyisocyanate and 20 to 30 parts of water, the polyether polyol composition is prepared from 30 to 52 percent of polyether polyol A, 25 to 50 percent of polyether polyol B and 5 to 15 percent of polyether polyol C; the functionality of the polyether polyol A is 2-3, and the hydroxyl value of the polyether polyol A is 25-60 mgKOH / g; the polyether polyol B is vinyl polymer grafted polyether polyol with the functionality of 3, and the hydroxyl value of the polyether polyol B is 21-32 mgKOH / g; and the functionality of the polyether polyol C is 3-6, and the hydroxyl value of the polyether polyol C is 350-500 mgKOH / g. The density of the polyurethane foam material is 3-8 kg / m < 3 >, the aperture ratio is larger than or equal to 95%, and the polyurethane foam material has the advantages of being light in weight, high in squaring amount, high in strength, not prone to shrinkage and the like.

The invention relates to a composite catalyst as well as a preparation method and application thereof, and mainly solves the problems of high temperature, more byproducts, catalyst residues, equipment corrosion, low catalytic efficiency of a novel catalyst and the like when a traditional strong acid catalyst system is used in the prior art. The research method comprises the following steps: preparing a sulfonic acid alkyl imidazole compound catalyst by a two-step method; 1 wt% of the catalyst is used for carrying out esterification reaction on polyhydric alcohol and fatty acid; after the reaction is finished, a product is separated from the catalyst, and the ionic liquid is recycled; and carrying out weak base washing, filtering and water washing refining on the product. The catalytic efficiency of the catalyst reaches up to 99.5% or above, the product hydroxyl value is smaller than 5 mgKOH / g, the acid value is smaller than 0.5 mgKOH / g, and the esterification efficiency is still kept to be 99.0% or above after the catalyst is recycled 6 times. The method has the advantages of simple process, mild reaction conditions and recyclable catalyst, well solves the problems of high temperature, catalyst residue, many byproducts and equipment corrosion in the traditional catalytic esterification system, and can be used in the preparation process of various ester products.

The invention provides a preparation process of a high-elastic pressure-resistant air-permeable and water-permeable sponge. The sponge is prepared from the following components in parts: 40 to 60 parts of highly branched polyester polyol, 37 to 43 parts of polyether polyol, 50 to 56 parts of isocyanate, 1.5 parts of multiwalled carbon nanotubes, 2.0 parts of nano silicon dioxide, 1.0 part of montmorillonite, 0.54 to 0.7 part of silane coupling agent, 2.0 to 3.1 parts of polyethylene glycol and 0.8 part of bimetallic catalyst. 1.8 parts of a foaming agent, 15 parts of a supercritical agent and 1.2 parts of an opening agent; the preparation method comprises the following steps: S1, carrying out segmented vacuum dehydration on highly branched polyester polyol and polyether polyol, carrying out xylene ultrasonic treatment on multi-walled carbon nanotubes and a silane coupling agent, and carrying out high-shear mixing to prepare a nanofiller dispersion liquid; through step-by-step dehydration, polyol thermal degradation is reduced, the hydroxyl value retention rate is improved, the integrity of a cross-linked network is ensured, through step-by-step dehydration and magnetic field dispersion, the problems of polyol thermal degradation and nano agglomeration are solved, and superuniform dissolution and precise regulation and control of double-peak aperture are realized through pulse injection and magnetic field coupling foaming.

The present application relates to a kind of core-shell type water-based hydroxyl acrylate microspheres emulsion and its preparation method and application. Core-shell water-based monodisperse acrylate emulsion is prepared by in-situ multi-stage variable speed drop method, including the following steps: core layer polymerization: after heating kettle bottom liquid, initiator solution is added, then multi-stage variable speed drop is added to core layer pre-emulsion containing core layer monomer, after adjusting pH using neutralizing agent, polyacrylate core layer emulsion is obtained;Shell polymerization: multi-stage variable speed drop is added to polyacrylate core layer emulsion containing shell pre-emulsion containing shell monomer and initiator solution, heat preservation, cooling, after reaction is completed, terminating agent is added, after adjusting pH using neutralizing agent, core-shell type water-based hydroxyl acrylate microspheres emulsion is obtained. The emulsion is used in exterior wall coating, wood coating or antirust coating field. Compared with prior art, the microspheres emulsion synthesized by the present application has the advantages of high solid content, high hydroxyl value, uniform particle size, etc.

A thermoplastic polyurethane resin elastomer is obtained by reacting an isocyanate compound (I), an aliphatic alcohol (II) having a number average molecular weight determined from the hydroxyl value of less than 300 and having only a hydroxyl group as a functional group, and a polyol (III) having a number average molecular weight determined from the hydroxyl value of not less than 300 and not more than 10,000. The isocyanate compound (I) includes not less than 90 mol % in total of an aliphatic isocyanate compound containing two isocyanate groups and / or an alicyclic isocyanate compound containing two isocyanate groups. The aliphatic alcohol (II) includes not less than 90 mol % of a C12 or lower aliphatic diol. The polyol (III) includes not less than 80 mol % of a copolymerized polycarbonate diol (IIIA) including a linear repeating structural unit represented by formula (A) and a repeating structural unit represented by formula (B).

The invention discloses waterborne polyester as well as a preparation method and application thereof. The preparation method comprises the following steps: putting an intermediate compound into a pre-polycondensation product to carry out polycondensation reaction; wherein the pre-polycondensation product is a product obtained by adding an auxiliary agent into an ester and carrying out polycondensation reaction until the hydroxyl value reaches 80 mgKOH / g-100 mgKOH / g, the chemical structural formula of the ester is shown in the specification, R1, R2 and R3 are independently selected from C4-C12 alkyl groups or aryl groups, R4 and R5 are independently selected from C2-C9 alkyl groups; the chemical structural formula of the intermediate compound is shown in the specification, R6 is C3-C6 alkyl, and R7 is methyl or ethyl. The super-hydrophilic coating prepared from the water-based polyester prepared by the method has super-hydrophilicity, high wear resistance and long service life, and is suitable for the fields of building glass, medical equipment, automobile glass, electronic screens and the like which require antifogging, self-cleaning and durability requirements.

The present disclosure relates to a two-component, solvent-based coating composition comprising i) a base component comprising one or more polyesterdiols with a hydroxyl value in the range of from 150 to 500 mg KOH / g and one or more organosilane-modified inorganic fillers, and ii) a polyisocyanate curing component. Said composition can be formulated such that it has a viscosity suitable for spray application (low viscosity under high shear rate) and yield coatings with very good erosion resistance. The present disclosure further relates to a method for coating a substrate using said two-component coating composition, to a coated substrate obtainable by such method, and to use of such coating composition for improving erosion resistance of a substrate.

To provide a resin composition which has good storage stability even under a high-temperature environment and is excellent in depth curability even with an LED light source.SOLUTION: A photocurable resin composition contains an epoxy (meth)acrylate, a pentaerythritol acrylate, a photopolymerization initiator, a phosphate ester, a thiol compound, and a light stabilizer. The pentaerythritol acrylate has a hydroxyl value of 170-350 mg KOH / g. The thiol compound contains a primary thiol.SELECTED DRAWING: None

The invention belongs to the technical field of polyurethane, and particularly relates to a temperature-resistant microporous filling material and a preparation method thereof. The temperature-resistant microporous filling material is prepared from a component A and a component B according to a mass ratio of 100: (93-95), the component A comprises the following raw materials: polyester polyol 1, polyester polyol 2, hydroxyl fluorosilicone oil, a hardener, a compound catalyst, water, a microsphere foaming agent and hollow glass beads; the component B comprises polyester polyol 2, pure MDI and liquefied MDI; the polyester polyol 1 is prepared by reacting maleic anhydride, polyester polyol with the hydroxyl value of 65-75 mgKOH / g and ethylene glycol. By introducing the hollow glass beads and utilizing maleic anhydride groups in the polyester polyol to enhance the dispersity, the processing fluidity, the dimensional stability, the mechanical property and the heat-resistant temperature of the material are synergistically improved, and the performance requirement of high-temperature forming of a carbon fiber product is met.

The present invention provides a film-forming composition that can easily remove a film layer from a general-purpose plastic substrate using a simple method. The film-forming composition of the present invention is a removable film-forming composition used to form a film on the surface of a substrate (A) directly or through another layer that is removable by treatment in an alkaline solution. The film-forming composition contains a urethane resin having a hydroxyl value, a weight-average molecular weight of 45,000 or greater, and a number-average molecular weight of 10,000 or greater. The hydroxyl value in the film-forming composition is preferably 1.0 mgKOH / g to 30.0 mgKOH / g.

This invention relates to the field of slow rebound foam technology, and particularly to a slow rebound foam based on waste PET polyether polyol, and its preparation method. The waste PET-based polyether polyol is obtained from bis(2-hydroxyethyl) terephthalamide obtained by aminolysis of waste PET as a starting material. This not only enables the recycling and reuse of waste PET, but also allows it to be used as a foaming material for slow rebound foam. The composite polyether is composed of polyether polyol I, polyether polyol II, waste PET-based polyether polyol, and polymer polyol. By adjusting and controlling parameters such as functionality, molecular weight, hydroxyl value, viscosity, and propylene oxide content of the waste PET-based polyether polyol, it can be stably stored at room temperature without crystallization. When used as the soft segment of slow rebound foam, it significantly improves the low-temperature resistance of the slow rebound foam, avoiding the problems of slow rebound polyurethane foam hardening and becoming difficult to cut in winter, as well as poor resilience.

A polyether polyol combination for compression-resistant slow-rebound polyurethane foam, polyurethane foam and a preparation method thereof, comprising the following raw materials in parts by weight: polyether polyol A 60-90 parts, polyether polyol B 5-20 parts, polyether polyol C 10-20 parts, silicone oil surfactant 1.5-2.5 parts, chemical foaming agent 2.5-3.5 parts, amine catalyst 0.3-0.8 parts; polyether polyol A is a high-EO polyether polyol, with a hydroxyl value of 30-50 mg KOH / g, a functionality of 3, an EO content of 70%-80%, a primary hydroxyl group content of 40%-60%, and is prepared by DMC catalyst catalysis; polyether polyol B is a low-EO polyether polyol, with a molecular weight of 2500-3500, a hydroxyl value of 50-80 mg KOH / g, a functionality of 3, an EO content of 5%-10%, a PO content of 85%-92%, and is prepared by DMC catalyst catalysis; polyether polyol C is an EO-free polyether polyol, prepared by DMC catalyst catalysis. The polyurethane slow-rebound foam prepared by the application has good recovery time and excellent compression resistance, and is easy to implement and simple to operate.

The utility model belongs to the technical field of carbon black production, and particularly relates to a system for preparing high-dispersity acetylene carbon black, which is connected with an outlet of a raw material acetylene carbon black production system and comprises a batching device and a conductive treatment device, the batching device comprises a H2O2 solution storage tank and a mixer; an outlet of the H2O2 solution storage tank and an outlet of the raw material acetylene carbon black production system are connected with an inlet of the mixer; the conductive treatment device comprises at least one carbon black modification cylinder, cover bodies are arranged at the two ends of the carbon black modification cylinder, conductive columns are arranged on the cover bodies and connected with a power source, and the mixer corresponds to the carbon black modification cylinder. The obtained high-dispersity acetylene carbon black has a dispersity value of 18.8 and a hydroxyl value of 0.33 mgKOH / g, and has higher dispersity, and an auxiliary agent is not introduced during preparation, so that the high-dispersity acetylene carbon black does not contain impurities and has higher purity; the resistivity of the high-dispersity acetylene carbon black is 1.25 omega.m, and the high-dispersity acetylene carbon black also has high conductivity.

The present invention relates to the use of a specific type of calcium catalyst (C) for the preparation of alkoxylated glycerides, the alkoxylated glycerides prepared in the presence of said catalyst, and a process for the preparation of alkoxylated glycerides. It has been found that in the presence of the above-mentioned calcium catalyst (C), the alkoxylation reaction requires significantly less time. In addition, it has been found that ethoxylated glycerides prepared in the presence of calcium catalyst (C) result in a more homogeneous product with significantly lower hydroxyl values, less decomposition, and improved processability.

Coating compositions, methods of producing a cured coating, and articles coated with a cured coating are provided. In an exemplary embodiment, a coating composition includes a crosslinking agent, an acrylic resin, a catalyst, and a catalyst blocker that blocks the catalyst. The crosslinking agent includes an alkylated melamine, and the acrylic resin has a hydroxyl value of from about 5 to about 110 milligrams potassium hydroxide per gram of acrylic resin. The catalyst includes a sulfonic acid, and the catalyst blocker includes an amine with a boiling point of about 300 degrees Celsius or higher.

The present disclosure provides aqueous dispersions of hydroxyl-functional core-shell particles. The particle core comprises a (meth) acrylic polymer and the shell comprises a polyurethane polymer. And the mass ratio of the core to the shell ranges from 20: 80 to 80: 20. The shell has a hydroxyl number of from 1 mg KOH / g to 40 mg KOH / g and an acid number of from 10 mg KOH / g to 60 mg KOH / g. The polyurethane is prepared from (a) a first prepolymer having a polymerizable ethylenically unsaturated group at one end and an active hydrogen functional group at the opposite end; (b) a second prepolymer having a polymerizable ethylenically unsaturated group at each end thereof; and (c) a third prepolymer having an active hydrogen functional group at each end thereof. Also provided are aqueous curable film-forming compositions, multi-layer coated substrates, and methods of improving adhesion and / or cohesion between coatings on a substrate.

A powder coating composition comprising an acid functional polyester resin A formed by reacting one or more polyol constituents, wherein at least 90 mole % of the polyols constituents is neopentylglycol, with one or more poly acid constituents wherein at least 87 mole % of the poly acid constituents is isophthalic acid (IPA); wherein polyester resin A has an Acid Number (AN) of between 20 and 90 mg KOH / g; and a hydroxyl value of less than 50, preferably less than 15 mg KOH / g; a glycidyl functional acrylic resin B having a weight average molecular weight of between 2500 and 7000; a curing catalyst C capable of catalyzing the reaction between the polyester resin A and the acrylic resin B; and optionally β-hydroxyalkylamide D.