阅读说明：本技术 可固化的树脂组合物 (Curable resin composition ) 是由 陈昱 冯艳丽 郭昆朋 郑辰 冯少光 陈欢 万晓欢 唐琦琦 于 2018-07-30 设计创作，主要内容包括：一种不含溶剂并适于原位固化的聚合物树脂组合物,其包含：(a)至少一种环氧树脂化合物；(b)至少一种异氰酸酯化合物；以及(c)催化剂体系,所述催化剂体系包含至少一种主催化剂和至少一种辅助催化剂的组合；其中所述主催化剂包括(ci)至少一种有机锑催化剂；并且其中所述辅助催化剂包括(cii)含氮催化剂；以及一种用于制备上述组合物的方法。(A solvent-free and suitable in situ-curing polymeric resin composition comprising: (a) at least one epoxy resin compound; (b) at least one isocyanate compound; and (c) a catalyst system comprising a combination of at least one procatalyst and at least one cocatalyst; wherein the procatalyst comprises (ci) at least one organoantimony catalyst; and wherein the helper catalyst comprises (cii) a nitrogen-containing catalyst; and a process for preparing the above composition.)

1. A solvent-free, in situ curable, reaction composition having oxazolidone and isocyanurate structures, comprising the reaction product of (a) at least one polyepoxide compound and (b) at least one polyisocyanate compound in the presence of (c) a catalyst system; wherein the catalyst system comprises at least one organoantimony catalyst; wherein the ratio of the at least one polyepoxide compound to the at least one polyisocyanate compound is from 1 to 1.5; and wherein the oxazolidinone/isocyanurate ratio of the composition is greater than 0.8.

2. The composition of claim 1, wherein the catalyst system comprises a primary catalyst and a secondary catalyst; and wherein the main catalyst is an organoantimony catalyst and the auxiliary catalyst is a nitrogen-containing catalyst.

3. The composition of claim 2, wherein the nitrogen-containing catalyst is 1, 8-diazabicyclo [5.4.0] undec-7-ene, 2-ethyl-4-methylimidazole, and mixtures thereof.

4. The composition of claim 2, wherein the ratio of the primary catalyst to the secondary catalyst is from 5 to 100.

5. The composition according to claim 1 wherein the oxazolidinone/isocyanurate ratio of the polyoxazolidone material is from greater than 0.8 to 5.

6. The composition of claim 1, wherein the polyepoxide compound is a bisphenol a epoxy resin; wherein the polyisocyanate compound is diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, or a diphenylmethane diisocyanate prepolymer; and wherein the catalyst system comprises a catalytic amount of at least one procatalyst comprising an organoantimony iodide.

7. The composition of claim 1, wherein the catalyst system comprises (i) a catalytic amount of at least one procatalyst comprising an organoantimony iodide and (ii) a catalytic amount of at least one cocatalyst comprising 1, 8-diazabicyclo [5.4.0] undec-7-ene.

8. The composition of claim 7, wherein the mass ratio of the organoantimony to the iodide is from 0.75 to 1.5.

9. The composition of claim 1, wherein the concentration of the polyepoxide compound is from 30 to 70 weight percent; wherein the concentration of the polyisocyanate compound is 30 to 70 wt%; and the concentration of the catalyst system is from 1 wt% to 3 wt%.

10. The composition of claim 1 wherein the polyepoxide and polyisocyanate each have an average functionality of from 2 to 3.

11. A process for preparing a curable resin composition comprising compounding (a) at least one polyepoxide compound and (b) at least one polyisocyanate compound in the presence of (c) a catalyst system; wherein the catalyst system comprises at least one organoantimony catalyst; wherein the ratio of the at least one polyepoxide compound to the at least one polyisocyanate compound is from 1 to 1.5; and wherein the oxazolidinone/isocyanurate ratio of the composition is greater than 0.8.

12. The method of claim 11, wherein the mixing temperature is about 25 ℃ to 60 ℃.

13. A cured thermoset resin product comprising a crosslinked cured product of a reaction composition of (a) at least one polyepoxide compound and (b) at least one polyisocyanate compound in the presence of (c) a catalyst system; wherein the catalyst system comprises at least one organoantimony catalyst; wherein the ratio of the at least one polyepoxide compound to the at least one polyisocyanate compound is from 1 to 1.5; and wherein the oxazolidinone/isocyanurate ratio of the composition is greater than 0.8.

14. A process for preparing a cured thermoset resin product comprising the steps of:

(I) compounding (a) at least one polyepoxide compound and (b) at least one polyisocyanate compound in the presence of (c) a catalyst system; wherein the catalyst system comprises at least one organoantimony catalyst; wherein the ratio of the at least one polyepoxide compound to the at least one polyisocyanate compound is from 1 to 1.5; and wherein the oxazolidinone/isocyanurate ratio of the composition is greater than 0.8; and

(II) heating the composition of step (I) at a curing temperature for a period of time to form a cured thermoset product.

15. The method of claim 14, wherein the curing temperature is from 80 ℃ to 220 ℃.

16. The method of claim 14, wherein the period of time for curing is 30 seconds to 1 hour.

Technical Field

The present invention relates to curable polymer resin compositions containing oxazolidone structures; and more particularly, to in situ curable polyisocyanurate based polyoxazolidone polymer resin compositions having high oxazolidone/isocyanurate ratios.

Background

It is well known to react polyepoxides with polyisocyanates in the presence of catalysts to form oxazolidone containing polymers or polyoxazolidone polymers. The oxazolidinone-containing polymer is also referred to by those skilled in the art as a "prepolymer" or "polymer precursor" because, after preparation of the oxazolidinone-containing polymer or polyoxazolidone polymer precursor, when the precursor is an isocyanate-terminated prepolymer, the precursor can then be used to prepare end products such as polyurethane films, elastomers, structural foams, rigid foams, flexible foams, and the like. Alternatively, when the precursor is an epoxy-terminated oxazolidinone prepolymer, the precursor can then be used to prepare end products such as epoxy coatings, resins, adhesives, and the like. Any conventional technique for preparing polyurethane and/or epoxy resins is used with known precursors. Thus, the prior art method comprises: as a first step, a prepolymer is prepared by reacting a polyepoxide and a polyisocyanate in the presence of a catalyst to form a polyoxazolidone prepolymer, which is then cured to form the final oxazolidone structure-containing curable polymer resin composition product for subsequent use. The use of such known prepolymers would add complexity and cost to the known process.

Therefore, it would be advantageous to eliminate the use of prepolymers in the preparation of curable polymer resin compositions containing oxazolidone structures. Additionally, it would be beneficial to provide the following curable polymer resin compositions containing oxazolidone structures: which does not require the use of prepolymers and still maintains excellent mechanical properties including tensile strength, flexibility and impact resistance as well as a high glass transition temperature (Tg). Furthermore, it would be an advance in the art to provide formulations comprising catalyst systems that can catalyze reactions at fast cure rates and higher Tg while maintaining high oxazolidone content and long shelf life at low temperatures.

U.S. patent No. 4,658,007 discloses a process for preparing polyisocyanurate-based polyoxazolidone polymers by reacting a polyepoxide and a polyisocyanate in the presence of a catalytic amount of an organo-antimony iodide catalyst. Although the above patent discloses a process, the patent reference is silent on the physical or mechanical properties or storage stability of the reacted composition. The above patent is not concerned with the preparation of reactive compositions having the following characteristics: (1) a final oxazolidinone/isocyanurate ratio content of 0.8 or greater, (2) improved storage stability, and/or (3) a glass transition temperature (Tg) (after curing of the composition) of greater than 190 ℃. These performance characteristics are all important characteristics for providing a composition that can be successfully used during application.

Disclosure of Invention

One embodiment of the present invention relates to a method for preparing a polyoxazolidone polymer based on a polyisocyanurate (or polyoxazolidone resin product) by reacting (a) at least one polyepoxide compound and (b) at least one polyisocyanate compound in the presence of (c) a catalyst system. The method can be used to prepare in situ curable polymer resin formulations or compositions that are solvent free and surprisingly achieve simultaneously high oxazolidone/isocyanurate ratio levels (e.g., greater than or equal to (≧)0.8) during curing.

It is therefore an object of the present invention to provide a polyoxazolidone polymer based on polyisocyanurate which: (1) prepared without using a prepolymer; (2) with a high oxazolidinone/isocyanurate ratio (e.g., > 0.8); and (3) can be cured in situ without solvent, i.e., no solvent is introduced or required in the formulation to dissolve the catalyst. During the curing of the formulation, the solvent tends to generate bubbles. Thus, it is advantageous to use solvent-free formulations. There are also cost advantages to using the in situ curing process of the present invention that does not require a prepolymer.

Another embodiment of the present invention includes a process for preparing a cured thermoset resin polymer product made from the polyisocyanurate-based polyoxazolidone polymer described above; after curing the polymer, the in situ cured polymer resin exhibits excellent characteristics, such as a high glass transition temperature (Tg) (e.g., greater than (>)190 ℃); high impact strength (e.g., >30kJ/m 2); high tensile strength (e.g., >80 MPa); high flexural strength (e.g., >130 MPa); and enhanced pot stability (e.g., >2 hours (h) at RT (room temperature, about (— 25 ℃). These performance characteristics are comparable or better than conventional products made from conventional oxazolidinone-containing prepolymers.

The beneficial results obtained by the oxazolidinone in situ cure chemistry of the invention disclosed above are achieved by using an appropriate polymer with high oxazolidinone content in the formulation, and by selecting the appropriate reactants (including polyepoxide compounds, polyisocyanate compounds, catalyst systems) and appropriate reactant dosages, catalyst ratios and cure temperatures.

For example, it is another object of the present invention to provide a catalyst system that can catalyze reactions at fast cure rates and high Tg while maintaining high oxazolidinone content and long shelf life of the formulation, which is important for successful application processes.

In one embodiment, a catalyst system having desirable characteristics may include, for example, a combination of at least one procatalyst (e.g., Ph3Sb + I2) and at least one cocatalyst (e.g., DBU or EMI). In addition, the present invention includes finding a beneficially narrow concentration range for the helper catalyst. It is known that co-catalysts can also catalyze side reactions of isocyanurates. Thus, it has been found that the maximum loading of the co-catalyst can be up to 0.04 wt% in order to maintain the oxazolidinone content of the formulation at a high level.

In another embodiment, the order of catalyst loading was found to affect the results of catalyst activity. For example, the following sequence: ph3Sb → DBU → I2 exhibits all beneficial properties such as high Tg, high oxazolidinone content and fast reactivity while maintaining formulation stability at lower temperatures (e.g. 25 ℃). It is speculated that the lewis acid Ph3Sb may react with DBU to form catalyst blocking when first combined with DBU, whereas when Ph3Sb first paired with I2, the resulting Ph3SbI2 once formed no longer reacts with DBU.

Detailed Description

In one broad embodiment, the present invention comprises a neat, solvent-free (i.e., solvent-free) curable thermoset polymer resin composition suitable for in situ curing. For example, the resin composition comprises: (a) at least one epoxy resin compound, such as d.e.r.383 and 127E; (b) at least one isocyanate compound, such as MDI or pMDI; and (c) a catalyst system comprising a combination of at least a first catalyst and a second catalyst; wherein the first catalyst comprises (ci) at least one antimony catalyst, such as Ph₃Sb; and wherein the second catalyst comprises (cii) iodine (I)₂) A catalyst.

The epoxy resin component (a) useful in preparing the thermosetting resinous polymer composition of the present invention may comprise, for example, a single epoxy resin or a mixture of two or more different epoxy resins. The epoxy resin component (a) may be solid or liquid at room temperature (about 25 ℃). If solid, the polyepoxide may be heat softened at elevated temperatures between 50 ℃ and 150 ℃. Mixtures of solid and liquid (at room temperature) polyepoxides may be used. The polyepoxide or mixture thereof suitably has an average Epoxide Equivalent Weight (EEW) of from 150 to 800, 170 to 400, and/or 170 to 250. Individual polyepoxides contained in the mixture may have EEWs outside this range. A variety of polyepoxide compounds can be used, such as cycloaliphatic epoxides, epoxidized phenolic resins, epoxidized bisphenol a or bisphenol F resins, but based on cost and availability, liquid or solid glycidyl ethers of bisphenols such as bisphenol a or bisphenol F may be preferred. Halogenated (especially brominated) polyepoxides can be used to impart flame retardant properties if desired. Polyepoxides of particular interest are the polyglycidyl ethers of bisphenol A or bisphenol F having an EEW of 150 to 800. A blend of one or more polyglycidyl ethers of bisphenol a or bisphenol F. If desired, the epoxy resin may be halogenated (especially brominated) to impart flame retardancy.

Suitable polyepoxides useful in the present invention can include commercially available polyepoxides. Among these polyepoxides are liquid polyepoxides such as d.e.r.317, d.e.r.330, d.e.r.331, d.e.r.332, d.e.r.336, d.e.r.337 and d.e.r.383; solid polyepoxides such as d.e.r.642u, d.e.r.661, d.e.r.662, d.e.r 663, d.e.r.671, d.e.r.672u, d.e.r.692, d.e.r.6155, d.e.r.666e, d.e.r.667-20, d.e.r.667e, d.e.r.668-20, d.e.r.669-60, d.e.r.669e and d.e.r.6225; brominated polyepoxides such as d.e.r.542, d.e.r.560, and d.e.r.593; epoxy novolac resins such as d.e.n.425, d.e.n.431, d.e.n 438, d.e.n.439 and 127E; and mixtures thereof; all of these are available from Olin.

In one exemplary embodiment, the epoxy compounds useful in preparing the thermosetting resin polymer composition may include, for example, brominated aromatic epoxy resins, non-brominated epoxy resins, bisphenol a epoxy resins, bisphenol F epoxy resins, biphenyl epoxy resins, naphthalene epoxy resins, divinylbenzene dioxide, and mixtures thereof.

Generally, the concentration of the epoxy resin component (a) used in the present invention may generally range from about 20 weight percent (wt%) to about 80 wt% in one embodiment, and from about 30 wt% to about 60 wt% in another embodiment, based on the total weight of all components in the composition.

The resin compositions or formulations of the present invention comprise at least one isocyanate component as component (b) of the formulation, i.e., the isocyanate component useful in the present invention may comprise one or more isocyanate-containing components. For example, the resin composition may comprise, for example, a single polyisocyanate or a mixture of two or more different polyisocyanates.

In general, suitable polyisocyanate compounds useful in the present invention can include aromatic, aliphatic, and cycloaliphatic polyisocyanates. For example, the polyisocyanate compound may include m-phenylene diisocyanate; 2, 4-and/or 2, 6-Toluene Diisocyanate (TDI); various isomers of diphenylmethane diisocyanate (MDI); so-called polymeric MDI products (pMDI); a carbodiimide-modified MDI product; hexamethylene-1, 6-diisocyanate; tetramethylene-1, 4-diisocyanate; cyclohexane-1, 4-diisocyanate; hexahydrotoluene diisocyanate; hydrogenated MDI; naphthalene-1, 5-diisocyanate; isophorone diisocyanate (IPDI) and mixtures thereof. Suitable examples of commercially available MDIs or pmdis may include, for example, OP50 and PAPI 27; and mixtures thereof.

Polyisocyanate component (b) can have an average functionality of isocyanate groups of, for example, from 2 to 2.7 in one embodiment, and from 2 to 2.3 in another embodiment.

Generally, the amount of polyisocyanate component (b) used in the resin formulation of the present invention may generally be, for example, from 20 to 80 weight percent in one embodiment, and from 40 to 70 weight percent in another embodiment, based on the total weight of all components in the formulation.

Catalyst system component (c) useful in the present invention includes the following combinations: (ci) a catalytic amount of at least one procatalyst, such as organoantimony iodides (Ph3Sb and I2); and (cii) a catalytic amount of at least one co-catalyst, such as 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU) and/or 2-ethyl-4-methylimidazole (EMI) catalyst or 1-methylimidazole; or mixtures thereof.

The main catalyst may include, for example, a first catalyst and a second catalyst; wherein the first catalyst comprises at least one antimony catalyst, such as triphenylantimony (Ph)₃Sb) and Ph₃Sb and iodine (I)₂) A derivative of (a); and wherein the second catalyst comprises a (cii) nitrogen-containing catalyst.

The helper catalyst can include, for example, a third catalyst and optionally a fourth catalyst; wherein the third catalyst comprises, for example, a DBU catalyst; and wherein the optional fourth catalyst may comprise an EMI catalyst.

In addition, a variety of other known catalysts may optionally be added to the catalyst system component (c) of the present invention. For example, optional catalysts useful in the present invention may include tertiary amines such as trimethylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N-dimethylbenzylamine, N-dimethylethanolamine, N' -tetramethyl-1, 4-butanediamine, N-dimethylpiperazine, bis (dimethylaminoethyl) ether, and triethylenediamine; tertiary phosphines such as trialkylphosphines and dialkylbenzylphosphines; chelates of various metals such As those obtainable from acetylacetone, benzoylacetone, trifluoroacetylacetone, ethyl acetoacetate, etc. with metals such As Be, Mg, Zn, Cd, Pd, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co and Ni; acidic metal salts of strong acids, such as ferric chloride, stannic chloride; salts of organic acids with various metals such as alkali metals, alkaline earth metals, Aal, Sn, Pb, Mn, Co, Ni, and Cu; and mixtures thereof. In another embodiment, organometallic derivatives of tetravalent tin, trivalent As and pentavalent As, Sb and Bi, and metal carbonyls of iron and cobalt; and mixtures thereof may also be used in the present invention. In yet another embodiment, tertiary amine catalysts such as N, N-trimethyl-N-hydroxyethyl-bis (aminoethyl) ether, dimethyl 1-2 (2-aminoethoxy) ethanol, and the like; and mixtures thereof may also be used in the present invention.

In the formulations of the present invention, the equivalent NCO to equivalent epoxy molar ratio: (mass of isocyanate x epoxy equivalent of epoxy resin)/(mass of epoxy resin x NCO equivalent of isocyanate) is in the range of 1.0 to 2.0 in one embodiment, and in the range of 1.2 to 1.5 in another embodiment.

The total mass of Ph3Sb and I2 in the formulation of the invention can be from 0.5 wt% to 2 wt% in one embodiment, from 1.0 wt% to 1.5 wt% in another embodiment, and from 1.0 wt% to 1.2 wt%. The mass ratio of Ph3Sb to I2 may be in the range of 0.72 to 1.44.

When a DBU catalyst and/or an EMI catalyst is used as a co-catalyst component, the co-catalyst can be used at a maximum loading value (e.g., up to 0.1 wt%) within a beneficially narrow concentration range. It is important to have a maximum loading of the co-catalyst to maintain the oxazolidinone content of the formulation at a high level. For example, the range of co-catalyst may be less than or equal to 0.1 wt% in one embodiment; and from 0.04 wt% to 0.1 wt% in another embodiment. It is known that co-catalysts can catalyze side reactions of isocyanurates, which can deleteriously affect the oxazolidinone content of the formulation. Thus, the maximum loading of the helper catalyst should be kept within a narrow range from 0.04 wt% to 0.1 wt%.

The two chemicals are mixed in solid form with the polyepoxide component or with the polyisocyanate component in sequence, without the need for solvents.

In one embodiment, the catalyst system (e.g., Ph)₃Sb and iodine (I)₂) Catalyst) are mixed in succession in the polyepoxide resin (component (a)).

In another embodiment, when the catalyst system includes an additional third catalyst such as DBU or EMI, the order of addition of the catalysts to the polyepoxide component is preferably as follows: ph3Sb → DBU/EMI → I2.

The advantage of using a small amount of co-catalyst is that a high oxazolidone content of the final product can be maintained by accelerating the reaction speed. The ratio of Ph3Sb and I2 is also important because Ph3SbI2 or Ph3SbI4 can catalyze reactions much faster than Ph3Sb alone. Moreover, the new catalyst loading sequence is also important because Ph3SbI2 or Ph3SbI4 alone is insoluble in epoxy resins; however, the combination of Ph3Sb and I2 may dissolve in the epoxy resin below 60 ℃. Furthermore, once I2 was added to the epoxy resin, I2 could react with Ph3Sb, after which the helper catalyst failed to form an acid-base pair with Ph3 Sb. Thus, the order of addition of the catalyst system to the epoxy resin is: first Ph3Sb, then the co-catalyst, and finally I2. In order to obtain the advantages of long activation period and fast reaction, the above-mentioned new addition sequence is preferred.

Various other optional conventional components may be added to the polymer resin formulation of the present invention. Suitable optional compounds or additives useful in the resin composition are well known in the art and may include, for example, molecular sieves for moisture absorption, mold release agents, surfactants, toughening agents, flow modifiers, tackifiers, diluents, stabilizers, plasticizers, catalyst deactivators, flame retardants, liquid nucleating agents, solid nucleating agents, Ostwald (Ostwald) ripening delay additives, and mixtures thereof.

Any suitable combination of the above optional additives and additive amounts, and methods of incorporating one or more optional additives into a resin composition, may be performed. Generally, each of the above optional additives, if used in the resin composition, does not exceed 10 wt%, based on total composition weight; and is advantageously used in the range of typically 0 to 10 wt%, preferably 0.001 to 10 wt%, more preferably 0.01 to 5 wt%, even more preferably 0.1 to 10 wt% and most preferably 0.1 to 1 wt%.

In a broad embodiment, the process for preparing the reactive thermosetting resin composition of the present invention comprises compounding the above components (a) - (c). One or more additional optional components may then be added to the formulation as desired. Typically, the preparation of the resin composition comprises mixing the components at a temperature of from 25 ℃ to 60 ℃ in one embodiment, and from 40 ℃ to 50 ℃ in another embodiment. The order of mixing of the ingredients is not critical, and two or more compounds may be mixed together, followed by addition of the remaining ingredients. The ingredients that make up the resin composition may be mixed together by any known mixing method and apparatus. Conventional methods and equipment for preparing the polymer resin composition may include, for example, a bench mixer.

In a preferred embodiment, the process for preparing the polyoxazolidone product is carried out by reacting (a) at least one polyepoxide compound and (b) at least one polyisocyanate compound in the presence of (c) a catalyst system. The method comprises for example the following successive steps: (I) reacting a polyepoxide compound in the presence of a catalyst system at a temperature of at least 50 ℃ or greater for a predetermined time to form a polyepoxide reaction mixture; and (II) after step (I), adding a polyisocyanate compound to the polyepoxide reaction mixture of step (I) and reacting the polyisocyanate compound with the polyepoxide reaction mixture of step (I) in the presence of a catalyst system at a temperature of less than 50 ℃ for a predetermined time to form a polyoxazolidone material having an oxazolidone/isocyanurate ratio of greater than 0.8. According to the above process steps, a polymer resin composition and a cured product made of the resin composition having improved characteristics can be obtained as described herein.

In another embodiment, the reaction temperature of step (I) of the above process may be, for example, 50 ℃ to 60 ℃; and the reaction temperature of step (II) may be, for example, 30 ℃ to 49 ℃.

In yet another embodiment, the process of the present invention may comprise a step (III) after step (II): the polyoxazolidone material is degassed under vacuum for a predetermined time to remove any bubbles formed during the reaction.

The polymer resin compositions of the present invention prepared by the process of the present invention have several advantageous properties and benefits compared to conventional formulations. For example, the resin has an oxazolidone/isocyanurate ratio > 0.8 in one embodiment, and from 0.2 to 2 in another embodiment; and desirably a high oxazolidinone content of from 0.4 to 1.5 in yet another embodiment. The oxazolidinone/isocyanurate ratio of the composition is important because high oxazolidinones provide better mechanical strength and high isocyanurates provide high glass transition temperature and flame retardant characteristics.

Another beneficial property exhibited by the compositions of the present invention may include the long shelf stability or shelf life of the composition, which may be >2 hours below 60 ℃ in one embodiment, and from 2 hours to 48 hours in another embodiment. "storage stability" or "pot life" with respect to a resin composition refers to the change in viscosity upon mixing. Storage stability or pot life can be measured in terms of the time at which the viscosity of the formulation is below 2pa.s at a specified temperature (e.g., 20 ℃). The long shelf life of the composition is advantageous at low temperatures, including, for example, -10 ℃ to 60 ℃ in one embodiment, and 25 ℃ to 60 ℃ in another embodiment. The long pot life of the composition is beneficial because it provides a long window of operating time, which in turn allows the material to be prepared without the need for in-line mixing equipment before the material is cured.

Gel time is another advantageous property exhibited by the compositions of the present invention. For example, the gel time of the composition may be from 180 seconds(s) to 400s in one embodiment, and from 120s to 300s in another embodiment. As mentioned above, the short gel time of the composition can result in high productivity and rapid curing.

Generally, after the reactive resin composition is prepared as described above, the composition may be cured in situ at a temperature of 80 ℃ to 210 ℃ in one embodiment, 100 ℃ to 210 ℃ in another embodiment, and 120 ℃ to 200 ℃ in yet another embodiment.

The formulations of the present invention also include a catalyst system that can catalyze reactions at fast cure rates. For example, the cure time of the composition at 120 ℃ may be from 100s to 400s in one embodiment, and from 200s to 300s in another embodiment. The cure time of the composition may determine the minimum heating time or processing time required for adequate curing.

The thermoset cured products prepared according to the present invention advantageously have several advantageous properties and benefits compared to conventional polymeric resins prepared from prepolymers. For example, the in situ cured polymer resin products prepared from the resin compositions of the present invention surprisingly and unexpectedly exhibit excellent properties, including, for example, a glass transition temperature (Tg) of >190 ℃ in one embodiment, a Tg of >190 ℃ to 230 ℃ in another embodiment, and a Tg of 160 ℃ to 200 ℃ in yet another embodiment. The appropriate Tg of a thermoset demonstrates the thermal stability of the material, and the Tg can be correlated to the highest temperature at which the thermoset retains its mechanical strength.

Additionally, the impact strength properties of the thermoset product as measured and determined by the procedure described in ISO179 may be, for example, in one embodiment>30kJ/m²And in another embodiment>30kJ/m²To 40kJ/m². The impact resistance properties of thermoset materials may demonstrate the toughness of the material.

Likewise, the tensile strength properties of the thermoset product measured and determined by the procedure described in ISO527 may be, for example, >80MPa in one embodiment, and from >80MPa to 100MPa in another embodiment. The tensile strength properties of a thermoset material may demonstrate the toughness of the material.

Another advantageous property of the thermoset product is its flexural strength. The flexural strength properties of the thermoset product measured and determined by the procedures described in ISO178 can be, for example, >130MPa in one embodiment, in another embodiment >160MPa, and in yet another embodiment >130MPa to 150 MPa. The flexural strength characteristics of thermoset materials may also demonstrate the toughness of the material.

Thermoset products prepared according to the present invention can be used in a variety of applications, including, for example, in composite applications, coating applications, and adhesive applications. In a preferred embodiment, the thermoset of the present invention can be used in composite applications.

Examples

The following examples are provided to illustrate the invention in further detail, but should not be construed to limit the scope of the claims. All parts and percentages are by weight unless otherwise indicated.

The various starting materials used in the examples below are explained in table I below.

TABLE I raw materials

Examples 1-6 and comparative examples A-E

The compositions described in table II for testing were prepared according to the general procedure described below; and the test results for the formulations prepared according to this procedure are also shown in table II.

General procedure for preparation of formulations

The compositions described in table II for the tests were prepared according to the following general procedure:

step (1): weighing Ph according to the formulation₃Sb and I₂Or other catalyst, and mixing the catalyst in the epoxy resin. The resulting mixture was then heated to 60 ℃ and the mixture was held at 60 ℃ for 1 hour. After one hour, the mixture was allowed to cool to room temperature (about 25 ℃).

Step (2): MDI or pMDI was added to the epoxy/catalyst mixture while the resulting mixture was mixed for 1 minute at 1,000 Revolutions Per Minute (RPM) using a high speed mixer.

And (3): any bubbles formed in the mixture were degassed from the mixture for 30 minutes under full vacuum using a vacuum furnace.

And (4): the material was cast into a mold and then cured in an oven with a ramp of 120 ℃ to 200 ℃ over 1 hour and held at 200 ℃ for an additional 2 hours.

And (5): thereafter, the solidified material was allowed to cool to room temperature; the cured material was then tested for Tg using the DSC mid-point method (10 deg.C/min as described in ISO 11357). Likewise, the mechanical properties of the cured material were measured using standard methods. For example, for measuring the tensile strength and elongation of the cured material, the method described in ISO527 may be used; to measure the flexural strength of the cured material, the method described in ISO178 may be used; and for measuring the impact strength of the cured material, the method described in ISO179 can be used.

And (6): the oxazolidinone/isocyanurate ratios of the materials were tested using FTIR equipped with a diamond ATR accessory. Can be measured by measuring 1750cm in FTIR spectrum^-1And 1700cm^-1(Baseline 1780-1560cm^-1) The peak height of (c) is divided to obtain the result.

And (7): the viscosity drift in G2 was tested in a 40 ℃ or 60 ℃ N2 or compressed air environment. The gel time can be measured at 120 ℃ on a hot plate open to air at a loading of 0.4 ml.

The test results for the formulations prepared according to the above procedure are also shown in table II.

The results described in table II show that inventive examples 1-3 exhibit higher oxazolidinone selectivity, expressed as a high oxazolidinone/isocyanurate content ratio, when the inventive formulations of examples 1-3 are compared to three control samples (comparative examples a-C). The results in table II also show that catalyst selectivity has a significant impact on the in situ curing process. In addition, the difference in Tg between inventive example 2 and inventive example 3 demonstrates the effect of isocyanate functionality on Tg. Furthermore, the difference in Tg and oxazolidinone functionality for inventive example 1 and inventive example 2 demonstrates the effect of NCO/epoxy ratio on Tg and oxazolidinone functionality of the formulation.

For the sample formulations described in table II above with high oxazolidinone/isocyanurate ratios, the mechanical properties including tensile strength, impact strength, and flexural strength were all better than the sample formulations with low oxazolidinone/isocyanurate ratios. Theoretically, the better mechanical properties of the formulations of the present invention are based on the influence of oxazolidinones. This data, set forth in table II, generally indicates that higher oxazolidone content (e.g., 0.05 to 1.1) is required to obtain a resin product with excellent mechanical properties.

Generally, known oxazolidinone-containing solutions include prepolymer solutions or foaming processes, which do not allow the production of clear castings with neat epoxy resins and diisocyanates or pMDI. Several unique steps in the process of the present invention include (1) forming the catalyst in situ in the epoxy resin, (2) the catalyst dosage, and (3) the cure temperature. The method or operating window of The present invention enables The in situ formation of oxazolidinone simultaneously with The curing process, as compared to resin products prepared using oxazolidinone prepolymers (e.g., VORAFORCE 200 series products available from The Dow Chemical Company), thereby providing superior mechanical properties to The resin products prepared from The compositions of The present invention. Due to the high viscosity of the oxazolidone containing polymer, the desired epoxy/NCO molar ratio should be far from 1 to avoid high degree of polymerization; and therefore, avoid high viscosities that naturally limit the oxazolidinone content of the polymer. Another advantage of the in situ curing process of the present invention is that the raw materials used to form the solvent-free in situ curable reaction composition of the present invention are free of oxazolidone; thus, the viscosity of the starting composition of the present invention is lower than prior art oxazolidinone prepolymers. Thus, the low viscosity compositions of the present invention may be advantageously used in a number of applications, such as coating applications or composite applications.

The data in table II above demonstrates the effect of cure temperature of the final product. The data show that temperatures above 120 ℃ have a positive effect on the selectivity of oxazolidinones. However, below 80 ℃, there is no change in selectivity even from 120 ℃ because the Tg is significantly reduced. These results indicate that the desired initial cure temperature is above 80 ℃, more preferably above 120 ℃ to obtain a resin with a high Tg (e.g., >190 ℃).

The data in table II above indicate that catalyst level is another important parameter for obtaining a suitable composition. When comparing the test results for the formulations of inventive example 1, inventive example 6, and comparative example E, the data in table II show that the catalyst loading of Ph3SbI4 can be advantageously higher than 1.1 wt% to maintain Tg above 190 ℃.

Example 7 and comparative examples F-L

The compositions described in table III for testing were prepared according to the general procedure described above; and the test results for the formulations prepared according to the above procedure are also shown in table III.

The data described in table III indicate that for the exemplary formulations using combinations of procatalysts (e.g., Ph3Sb and I2) and cocatalyst (e.g., DBU or EMI) at low loadings (e.g., less than 0.04 wt%), the Tg of the resulting resin product is higher than for the exemplary formulations using only the procatalysts Ph3Sb and I2. At the same time, for oxazolidinone selectivity (oxazolidinone/isocyanurate ratio), for example, the formulations using the procatalyst and cocatalyst are much higher than the formulations using the cocatalyst alone. Thus, the use of a low concentration of the helper catalyst provides a resin product having the advantages of a high Tg with a high oxazolidone content.

The data described in table III also show that the formulations containing the co-catalyst exhibit good reaction rate performance. As shown in table III, the gel time results for comparative example J using the catalyst combination of Ph3Sb and I2 catalysts were higher than inventive example 7. The gel time, which depends on the curing temperature (e.g., 120 ℃, and lower temperatures, such as 40 ℃ or 60 ℃), is significantly reduced (e.g., by 50% to 70%) after the helper catalyst is introduced into the formulation. This reduction in gel time indicates an increase in reactivity under all of the above conditions.

The effect of the order of catalyst loading in the exemplary formulations on the characteristics of the exemplary formulations can be seen from the results set forth in Table III. The formulation of example 7 of the present invention was the same as the formulation of comparative example G. However, the order of loading of the catalyst used in inventive example 7 was different from comparative example G. The Tg, oxazolidone content and gel time are almost the same at the curing temperature of the formulations of inventive example 7 and comparative example G. However, at lower temperatures (such as 40 ℃ and 60 ℃), the formulation of example 7 of the present invention exhibited superior stability compared to the stability of the formulations of comparative example G and comparative example J. Thus, for applications requiring longer open times at room temperature (e.g., 25 ℃), the formulation of example 7 of the present invention exhibits high Tg, high oxazolidinone content, and fast cure at high temperatures (e.g., 120 ℃) and excellent stability at low temperatures (e.g., 40 ℃).