Polyurethane acrylate mixed compound containing oxazolidine moisture scavenger and preparation method thereof

Abstract

The present invention relates to a urethane acrylate hybrid composition comprising the reaction product of: an isocyanate component comprising one or more isocyanate compounds and one or more initiators; and an isocyanate reactive component comprising one or more polyether polyols and / or polyester polyols; one or more hydroxyl functional acrylate monomers; and one or more moisture scavengers.

Description

Technical Field

[0001] Embodiments are directed to polyurethane acrylate hybrid compositions containing oxazolidine moisture scavengers. Background Art

[0002] Polyurethane (PU) hybrid resin systems containing acrylic monomers have a wide range of applicability and offer a range of cure times, low exotherm, good surface quality, toughness and fatigue resistance. PU acrylate hybrid systems can be used in several areas, including composite manufacturing processes that require long open times, such as vacuum infusion or pultrusion molding for the manufacture of articles such as window frames, household appliances, furniture and wind turbine blades. Although PU acrylate hybrid materials have certain advantages, they also have disadvantages: in particular, moisture control is difficult because moisture can be present not only in the PU formulation, but also in various other components of the composite, such as the core material, fiber reinforcement and flow medium. The presence of moisture can produce unwanted byproducts with the isocyanate component, resulting in several physical and mechanical defects. The increased costs associated with dehydration and humidity control reduce the advantages of such materials. Summary of the invention

[0003] Embodiments disclosed herein include polyurethane acrylate hybrid compositions comprising the reaction product of: an isocyanate component comprising one or more isocyanate compounds and one or more initiators; and an isocyanate reactive component comprising: one or more polyether polyols and / or polyester polyols; one or more hydroxyl functional acrylate monomers according to the formula:

[0004]

[0005] wherein R1 is selected from hydrogen, methyl or ethyl, R2 is selected from alkylene having 2 to 6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene)benzene, 1,3-bis(methylene)benzene, 1,2-bis(methylene)benzene, and n is an integer selected from 1 to 6; and one or more moisture scavengers according to the formula:

[0006]

[0007] wherein R1 is hydrogen, a methyl group, a branched or straight-chain alkyl or alkanol group, or forms a 4- to 7-membered ring with R2; R2, R3, R4 and R6 are each a hydrogen atom, a methyl group or a group, a straight-chain or branched alkyl or alkanol group, a cycloalkyl group or an aryl group; R5 is a methyl or hydroxymethyl group, or a branched or straight-chain alkyl or alkanol group; R7 is a hydrogen atom, a straight-chain or branched alkyl or alkanol group, a cycloalkyl group, a carbonyl group or an aryl group. DETAILED DESCRIPTION

[0008] Embodiments relate to PU acrylate hybrid systems that include moisture scavengers to reduce moisture sensitivity and improve the appearance and mechanical properties of articles formed therefrom. The PU acrylate hybrid system includes one or more oxazolidine-based moisture scavengers that can be combined with isocyanate-reactive components and isolate residual moisture. Specifically, the oxazolidine-based moisture scavenger reacts with moisture to generate an amine- and hydroxyl-containing substance that can then react with one or more isocyanate components such as diisocyanates, polyisocyanates, or polyurethane prepolymers. Therefore, side reactions with the moisture scavenger can prevent the isocyanate from reacting with water to form carbon dioxide.

[0009] The PU acrylate hybrid composition can be generated by reacting an isocyanate component with an isocyanate reactive component containing one or more moisture scavengers. The isocyanate component may include at least one compound having an isocyanate group. The isocyanate component may include one or more isocyanates and a polyisocyanate having an average of at least 2.0 isocyanate groups per molecule. The isocyanate component may contain aliphatic, alicyclic, alicyclic, aromatic, aromatic and / or derivatives thereof. Preferably, the isocyanate component contains a portion in which the NCO group is directly attached to the aromatic ring. Examples of compounds suitable for isocyanate components include monomeric methylene diphenyl diisocyanate (MDI), modified MDI, oligomeric MDI, polymeric MDI, toluene 2,4- / 2,6-diisocyanate (TDI), etc. The isocyanate may have an average isocyanate functionality of 2 to 5, 2.2 to 5, or 2.2 to 4. The isocyanate may have an isocyanate equivalent weight (EW) in the range of 75 g / eq to 250 g / eq, 80 g / eq to 200 g / eq, or 80 to 175 g / eq.

[0010] The isocyanate component may include one or more prepolymers formed by the reaction of a polyisocyanate compound and a polyol, including, for example, the reaction of 4,4'-MDI and tripropylene glycol, or the reaction of ethylene oxide-terminated propoxylated glycerol and 4,4'-MDI. The prepolymer may have an NCO content of 5 wt % to 30 wt %, 10 wt % to 25 wt %, or 15 wt % to 25 wt %. The isocyanate component may include a prepolymer in the range of 5 wt % to 70 wt %, 10 wt % to 65 wt %, or 15 wt % to 60 wt % by weight.

[0011] The isocyanate reactive component may include a polyol blend comprising, by weight percentage (wt%) of the blend, one or more polyether polyols and / or polyester polyols in the range of 35 wt% to 75 wt% and one or more hydroxyl functional (meth)acrylates in the range of 35 wt% to 75 wt%. As used herein, "(meth)" when used with various acrylate species indicates that the scope of the present specification encompasses both the acrylate or methacrylate variants of the referenced compounds.

[0012] The isocyanate reactive component may include one or more polyether polyols, which are prepared by adding an alkylene oxide such as propylene oxide and / or ethylene oxide to a polyhydroxy functional starting compound in the presence of a catalyst known in the art. The polyether polyol may be prepared from a starting compound and one or more alkylene oxides (e.g., ethylene oxide, butylene oxide and / or propylene oxide). The starting compound may include molecules having 2 to 8 hydroxyl groups per molecule, such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butylene glycol, 1,6-hexanediol, bisphenol A, glycerol, trimethylolpropane, pentaerythritol, sugars and sugar alcohols such as sucrose and sorbitol, etc.

[0013] The polyether polyol may have an average hydroxyl value (OH value) in the range of 100 to 500 mg KOH / g, 150 to 450 mg KOH / g, or 200 to 450 mg KOH / g as determined according to ASTM D4274-21.

[0014] The polyester polyol disclosed herein includes the reaction product of one or more carboxylic diacids and a polyol with 2 to 4 OH functionalities. Suitable carboxylic acids may include aromatic diacids or anhydrides and C4 to C12 aliphatic diacids. Suitable polyols for forming polyesters include one or more alkylene glycols or polyalkylene glycols with 2 to 4 hydroxyl functionalities, such as ethylene glycol, 1,2- or 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, glycerol, etc. Examples of polyester polyols include polyesters of phthalic anhydride and diethylene glycol, and polyesters of C4 to C12 diacids (such as succinic acid or adipic acid) and diethylene glycol.

[0015] The polyester polyol may have an average hydroxyl value (OH value) in the range of 100 to 500 mg KOH / g, 150 to 450 mg KOH / g, or 200 to 450 mg KOH / g as determined according to ASTM D4274-21.

[0016] The isocyanate-reactive component may include one or more polyester polyols in an amount by weight (wt %) ranging from 10 wt % to 40 wt %, from 15 wt % to 35 wt %, or from 15 wt % to 30 wt %.

[0017] The isocyanate reactive component may include one or more hydroxyl functional (meth) acrylate monomers that react with the isocyanate component and / or polymerize in the presence of a free radical initiator to produce a PU acrylate hybrid composition. The hydroxyl functional (meth) acrylate monomer may have the following general structure:

[0018]

[0019] wherein R1 is selected from hydrogen, methyl or ethyl; R2 is selected from alkylene having 2 to 6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene)benzene, 1,3-bis(methylene)benzene, 1,2-bis(methylene)benzene; and n is an integer selected from 1 to 6. The hydroxyl-functional (meth)acrylate monomer may include a hydroxy C1-10 (meth)acrylate alkyl ester monomer, such as hydroxyethyl acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate monomer, and the like.

[0020] The added amount of the hydroxyl functional (meth)acrylate can range from 15 wt % to 40 wt %, 20 wt % to 38 wt %, 25 wt % to 35 wt % or 27 wt % to 32 wt % based on the weight percentage (wt %) of the polyurethane acrylate hybrid composition.

[0021] The isocyanate reactive component includes one or more moisture scavengers containing an oxazolidine ring, an oxazolidine derivative, and any other type of moisture scavenger in combination with an oxazolidine or its derivatives. The moisture scavenger includes compounds described by the following formula:

[0022]

[0023] wherein R1 is hydrogen, a methyl group, a branched or straight-chain alkyl or alkanol group, or forms a 4- to 7-membered ring with R2; R2, R3, R4 and R6 are each a hydrogen atom, a methyl group or a group, a straight-chain or branched alkyl or alkanol group, a cycloalkyl group or an aryl group; R5 is a methyl or hydroxymethyl group, or a branched or straight-chain alkyl or alkanol group; R7 is a hydrogen atom, a straight-chain or branched alkyl or alkanol group, a cycloalkyl group, a carbonyl group or an aryl group.

[0024] Specific examples include 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine (CAS: 143860-04-2). The moisture scavenger may be added in an amount ranging from 0.05 wt % to 15 wt %, from 0.1 wt % to 10 wt %, or from 1 wt % to 10 wt % based on the weight percentage (wt %) of the polyurethane acrylate hybrid composition.

[0025] The polyurethane acrylate hybrid composition may include one or more initiators (e.g., free radical initiators) added to the isocyanate component. Initiators include, but are not limited to, peroxides, persulfides, peroxycarbonates, peroxyboric acid, azo compounds, or other suitable free radical initiators that can initiate the curing of double bond-containing compounds. Suitable initiators include azo compounds or peroxides. Preferably, the azo compound can be 2,2-azobisisobutyronitrile (AIBN); the peroxide is selected from the group consisting of: tert-butyl perbenzoate, butyl 4,4-di(tert-butylperoxy)valerate, di-tert-amyl peroxide, diisopropyl peroxide, di(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peroxide isopropyl benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, di-tert-butyl peroxide, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane, isopropyl hydroperoxide isopropyl benzene, 1,1,3,3-tetramethylbutyl hydroperoxide, isopropyl hydroperoxide, tert-butyl hydroperoxide and any combination thereof.

[0026] The polyurethane acrylate hybrid composition may include greater than 0 wt % initiator by weight percentage (wt %), including at least 0.1 wt %, at least 0.2 wt %, or at least 0.3 wt %, and up to 6.0 wt %, up to 5.0 wt %, or up to 4.0 wt %.

[0027] The isocyanate reactive component may include one or more accelerators, including metal salts such as cobalt and zinc salts that catalyze free radical polymerization reactions. The amount of accelerator added may range from 0 wt % to 0.15 wt %, 0.001 wt % to 0.10 wt %, or 0.01 wt % to 0.05 wt % based on the weight percentage (wt %) of the polyurethane acrylate hybrid composition.

[0028] Catalysts for promoting PU reactions may also be added, including amine catalysts, organometallic catalysts, or mixtures thereof. Amine catalysts may include one or more of triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethylethylenediamine, pentamethyldiethylenetriamine, N-methylaniline, N,N-dimethylaniline, etc. Organometallic catalysts may include organotin compounds, such as tin acetate (II), tin octoate (II), tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, etc. The amount of catalyst added may be in the range of 0 wt % to 0.15 wt %, 0.001 wt % to 0.10 wt %, or 0.01 wt % to 0.05 wt % based on the weight percentage (wt %) of the polyurethane acrylate mixed composition.

[0029] The isocyanate-reactive component may also contain one or more additives, including blowing agents, surfactants, crosslinking agents, plasticizers, fillers, smoke suppressants, flavors, reinforcing agents, dyes, colorants, pigments, preservatives, odor masking agents, physical blowing agents, chemical blowing agents, flame retardants, internal mold release agents, biocides, antioxidants, UV stabilizers, antistatic agents, thixotropic agents, adhesion promoters, cell openers, and the like.

[0030] The PU acrylate hybrid composition may include one or more silicone or organic defoamers in a range of 0.05 wt % to 5 wt %, 0.1 wt % to 1.5 wt % or 0.1 wt % to 1 wt % based on the weight percentage (wt %) of the PU acrylate hybrid composition.

[0031] The PU acrylate hybrid composition can be used in any suitable method for developing articles and composite materials, including molding, injection, vacuum infusion, pultrusion, etc. In one method, the PU acrylate hybrid composition can be prepared by the following steps: mixing an isocyanate component and an isocyanate-reactive component to form a mixture; processing the mixture in a mold to produce a molded article; and demolding the molded article.

[0032] PU acrylate hybrid compositions can be used to prepare molded composite parts. For the preparation of composite parts, the polyurethane-poly (meth) acrylate reactive composition is mixed with a reinforcing material or injected into the reinforcing material, for example, by vacuum assisted resin transfer molding (VARTM) and / or resin transfer molding (RTM). Suitable reinforcing materials include any one or more of glass fibers, carbon nanotubes, carbon fibers, polyester fibers, natural fibers, aramid fibers, nylon fibers, basalt fibers, boron fibers, silicon carbide fibers, asbestos fibers, whiskers, hard particles, metal fibers, etc.

[0033] The composite article prepared using the PU acrylate hybrid composition of the present invention may include one or more reinforcing materials in a weight percentage (wt %) range of 1 wt % to 90 wt %, 30 wt % to 90 wt %, 50 wt % to 85 wt % or 50 wt % to 80 wt %.

[0034] The composite product prepared using the PU acrylate hybrid composition of the present invention may also include one or more core materials to facilitate molding and weight reduction of the composite material. The core material may include polystyrene foam, polyester PET foam, polyimide PMI foam, polyvinyl chloride foam, metal foam, cellulose, wood such as balsa wood, etc.

[0035] The polyurethane acrylate hybrid composition can produce products and composite materials with excellent mechanical properties, such as high heat distortion temperature, high tensile and flexural strength, high fatigue resistance, high ductility and low shrinkage. The products and composite materials can be used to manufacture wind turbine blades, wind turbine nacelle shells, ship propeller blades, hulls, interior and exterior automotive decorative parts, automobile bodies, radar covers, mechanical structural components, decorative parts and structural components of buildings and bridges, etc.

[0036] Example

[0037] The following examples are provided to illustrate embodiments of the present invention and are not intended to limit the scope of the invention. Table 1 provides the materials used in the following examples.

[0038]

[0039] Example 1: Properties of Transparent Cast Polyurethane Acrylate Hybrid Compositions

[0040] In this example, the transparency of the cast sample (IS1) of the present invention containing a moisture scavenger was determined relative to the comparative sample (CS2) formulated without the moisture scavenger. The samples were prepared by blending the formulation components in the proportions specified in Table 2, all units are grams unless otherwise specified. The sample amount was prepared on a 200 gram scale and blended by a high-speed stirrer. The obtained liquid resin was degassed for 6 minutes and cast in a flat mold to a thickness of 4.5 mm. The sample was cured in a 70°C oven for 6 hours until fully cured.

[0041] The samples were then demolded and visually inspected for clarity. Sample CS1 exhibited significant haze and numerous bubble defects. In contrast, IS1 exhibited high clarity and no visible bubbles or defects.

[0042] Mechanical properties were determined according to standard ISO-527-2. The reported values ​​are the average of 5 repeated measurements.

[0043] The example formulations are shown in Table 2, and the mechanical testing results are shown in Table 3.

[0044]

[0045]

[0046] Example 2: Preparation of PU acrylate mixed laminate

[0047] In this embodiment, a laminate containing one or more PU acrylate mixed layers is prepared. Four layers of unidirectional glass fiber fabric (1200gsm, 0°) with a length-width of 500mm-500mm are laid on the mold, followed by a release film with a length-width of 500mm-500mm, a third layer containing a peeling layer and a third layer of circulation net. An injection hose with a length of 300mm is obtained by cutting and fixed next to the circulation net by two circles of adhesive sealing strips around each layer laid in the mold. The layers are then sealed with two layers of vacuum bag film. A vacuum pump is connected to the injection hose and the system is depressurized to 0 to 20 mbar, while the degassed PU acrylate mixed composition (CS1 or IS1) from Example 1 is directly injected. After injection, it is cured at 70°C for 6 hours and then demolded. Auxiliary materials such as peeling layers and circulation nets are then removed, and the resulting laminate is cut into samples according to the corresponding test standards.

[0048] The samples were then visually inspected for clarity and the presence of defects. In laminated sample CS2, white spots and defects were visible on the surface of the sample. In contrast, the laminate prepared with IS2 exhibited high clarity and no obvious defects.

[0049] The mechanical properties of the laminate were also checked according to standard ISO-527-5. The results are shown in Table 4.

[0050]

[0051] Due to the moisture sensitive nature of polyurethane based materials, absorbed / trapped moisture in the resin, fibers and all other core materials will lead to quality defects in the final product production. Oxazolidine based moisture scavengers improve the appearance and mechanical quality.

[0052] While the foregoing is directed to illustrative embodiments, other and further embodiments may be devised without departing from the basic scope of the present invention, which is defined by the claims that follow.

Claims

1. A polyurethane acrylate hybrid composition comprising the reaction product of the following components: an isocyanate component comprising one or more isocyanate compounds and one or more initiators; and An isocyanate-reactive component, the isocyanate-reactive component comprising: one or more polyether polyols and / or polyester polyols; One or more hydroxyl functional acrylate monomers according to the formula: wherein R1 is selected from hydrogen, methyl or ethyl, R2 is selected from an alkylene group having 2 to 6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene)benzene, 1,3-bis(methylene)benzene, 1,2-bis(methylene)benzene, and n is an integer selected from 1 to 6; and One or more moisture scavengers according to the formula: wherein R1 is hydrogen, a methyl group, a branched or straight-chain alkyl or alkanol group, or forms a 4- to 7-membered ring with R2; R2, R3, R4 and R6 are each a hydrogen atom, a methyl group or a group, a straight-chain or branched alkyl or alkanol group, a cycloalkyl group or an aryl group; R5 is a methyl or hydroxymethyl group, or a branched or straight-chain alkyl or alkanol group; R7 is a hydrogen atom, a straight-chain or branched alkyl or alkanol group, a cycloalkyl group, a carbonyl group or an aryl group.

2. The polyurethane acrylate hybrid composition according to claim 1, wherein the added amount of the hydroxyl functional acrylate monomer is in the range of 15 wt % to 40 wt % based on the weight percentage (wt %) of the polyurethane acrylate hybrid composition.

3. The polyurethane acrylate hybrid composition according to claim 1, wherein the isocyanate reactive component further comprises a cobalt salt accelerator.

4. The polyurethane acrylate hybrid composition according to claim 1, wherein the addition amount of one or more polyether polyols and / or polyester polyols is in the range of 10 wt % to 40 wt % based on the weight percentage (wt %) of the polyurethane acrylate hybrid composition.

5. The polyurethane acrylate hybrid composition of claim 1, wherein the one or more moisture scavengers is 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine.

6. The polyurethane acrylate hybrid composition according to claim 1, wherein the one or more moisture scavengers are added in an amount ranging from 0.1 wt% to 10 wt% based on the weight percentage (wt%) of the polyurethane acrylate hybrid composition.

7. A composite product, wherein the composite product is prepared from the polyurethane acrylate mixed composition according to claim 1.

8. A method for preparing the polyurethane acrylate hybrid composition according to claim 1, the method comprising: combining the isocyanate component and the isocyanate-reactive component to form a mixture, further comprising one or more reinforcement materials and / or core materials; processing the mixture in a mold to produce a molded article; as well as The molded article is demoulded.

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