RU2780087C2 - Polyisocyanurate-containing foam materials with long-term transition between mixing of components and transition to creamy mass and capability of instant curing - Google Patents

Abstract

FIELD: composite materials.

SUBSTANCE: invention can be used for the manufacture of composite materials for interior decoration of cars. A reaction mixture for the manufacture of polyisocyanurate-containing foam material with a density in the range of 50-500 kg/m³ includes polyisocyanate, isocyanate-reactive, and catalyst compositions, as well as a foaming agent. The reaction mixture has an isocyanate index of at least 200. The catalyst composition includes at least 50 wt.% of a trimerization catalyst. The isocyanate-reactive composition includes 0.1-30 wt.% of polyol with molecular weight of less than 200 g/mol. The foaming agent contains at least 50 mol.% of water per the total molar amount of all foaming agents. A method for the production of polyisocyanurate-containing rigid foam material, polyisocyanurate-containing material, the use of polyisocyanurate-containing, and composite material are also proposed.

EFFECT: increase in time between mixing of components and transition to creamy mass, while saving a capability of a reaction mixture of fast curing.

19 cl, 4 tbl, 14 ex

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates to a reaction mixture for the manufacture of polyisocyanurate-containing porous materials, in particular, polyisocyanurate-containing rigid foams for use in composite materials such as honeycombs.

In addition, the present invention relates to a process for the preparation of said polyisocyanurate-containing materials, whereby both a long period between mixing of the components and the transition to a creamy mass, and an instant curing behavior are achieved.

In addition, the present invention contemplates a polyisocyanurate-containing foam suitable for the production of composite materials.

BACKGROUND OF THE INVENTION

The current technology for making polyisocyanurate-containing foams suitable for making composite honeycomb structures, however, has several technological problems, such as too short a period between mixing of the components and the transition to a creamy mass and/or too long a curing period.

It is an object of the present invention to provide a reaction mixture which is intended for the production of polyisocyanurate-containing composite materials and which enables the production of polyisocyanurate-containing composite materials with greater processing flexibility, especially in terms of the period between mixing the components and the transition to a creamy mass and the ability to instantly cure.

US 6,602,927 provides polyisocyanurate systems for making polyisocyanurate foam components. The reaction systems include a polyisocyanate and a polyisocyanate-reactive component that includes a trimerization catalyst, a polyol, and a carboxylic acid blowing agent, optionally with water as a co-blowing agent. Reaction systems can be foamed solely with carboxylic acid to produce SRIM (structural reaction injection molding) products that can be demoulded with reduced mold residence time. US'927, however, does not provide sufficient processing flexibility for primarily water-foamed (having at least 50 mole % water, based on the total molar amount of all blowing agents used) polyisocyanurate systems, especially with regard to the time between mixing. components and the transition to a creamy mass and the ability to instant curing.

US 5,109,031 deals with low density, rigid, porous polymers made by reacting an organic polyisocyanate and a polyol component comprising a (polyester)polyol having a free glycol content of less than about 7 percent by weight relative to the (polyester)polyol, in the presence of a blowing agent. The purpose of the US'031 patent is to improve thermal insulation properties. US'031, however, does not provide sufficient processing flexibility for foamed primarily with water (having at least 50 mol.% water, based on the total molar amount of all blowing agents used) polyisocyanurate porous systems of higher density, especially in the ratio of the period between mixing the components and the transition to a creamy mass and the ability to instant curing.

US 6,207,725 also relates to a process for the preparation of rigid polyurethane or urethane-modified polyisocyanurate foams made by reacting an organic polyisocyanate composition and an isocyanate-reactive composition comprising a (polyester)polyol in the presence of an amine catalyst. The purpose of the US'725 patent is to achieve a rapid initial foam rise. Thus, the US'725 patent does not provide any technological details for foamed mainly with water (having at least 50 mol.% water, based on the total molar amount of all blowing agents used) systems by which between the mixing of the components and the transition to a creamy mass and the behavior of instant curing.

The object of the invention is to improve the processing technology for the manufacture of polyisocyanurate foams suitable for use in composite materials such as honeycombs. The object is to provide a polyisocyanurate-containing foam while achieving both a long period between mixing of the components and the transition to a creamy mass of at least 35 seconds, and instant curing behavior. The instant cure capability will result in more efficient curing and will reduce cycle time, while a long period between mixing the components and going into a creamy mass will provide flexibility in terms of processing time, e.g. filling the mold before curing.

Unexpectedly, Applicants have found a reaction mixture for the manufacture of polyisocyanurate-containing foams that exhibit both a long period between mixing the components and the transition to a creamy mass, and the ability to instantly cure.

The reaction mixture of the present invention results in a prolonged period between mixing of the components and transition to a creamy mass and the ability of instant curing, which allows for easier processing on laminating machines and potentially also allows the formation of PIR foams, which is currently not feasible with using state of the art reaction mixtures due to the limitations of the foaming kinetics of state of the art reaction mixtures.

SUMMARY OF THE INVENTION

According to a first aspect, a reaction mixture is disclosed for the manufacture of a polyisocyanurate (PIR)-containing foam having a density in the range of 50-500 kg/m ³ , wherein said reaction mixture has an isocyanate index of at least 200 and contains at least:

a polyisocyanate composition comprising one or more polyisocyanate compounds;

a catalyst composition comprising at least a trimerization catalyst compound in an amount of at least 50% by weight, based on the total weight of all catalyst compounds in the catalyst composition;

- an isocyanate-reactive composition comprising at least a low molecular weight (MW) polyol having an MW below 200 g/mol, in an amount of from 0.1 to 30% by weight, based on the total weight of the isocyanate-reactive composition ;

- one or more foaming agents containing at least 50 mol%. water, based on the total molar amount of blowing agents;

optionally one or more surfactants, one or more flame retardants, one or more antioxidants, or combinations thereof;

where % wt. trimerization catalyst compounds is < 0.5 wt %, based on the total weight of trimerization catalyst compounds+polyisocyanate composition.

According to embodiments, % wt. trimerization catalyst compounds is <0.5 wt%, preferably <0.45 wt%, more preferably <0.4 wt%, most preferably <0.35 wt%, based on the total weight of the catalyst composition+polyisocyanate compositions.

According to embodiments, % wt. trimerization catalyst compounds is <0.3% wt., based on the total weight of the catalyst composition+polyisocyanate composition.

In embodiments, the trimerization catalyst compound is selected from organic salts, preferably organic alkali metal, alkaline earth metal and/or quaternary ammonium salts, such as potassium acetate, potassium hexanoate, potassium ethylhexanoate, potassium octanoate, potassium lactate, N-hydroxypropyl-trimethyl-octanoate. ammonium, N-hydroxypropyl-trimethyl-ammonium formate, and mixtures thereof.

In embodiments, the low molecular weight (MW) polyol has a molecular weight below 150 g/mol, preferably below 100 g/mol.

In embodiments, the low molecular weight (MW) polyol is selected from glycerol and/or ethylene glycol.

In embodiments, the amount of low molecular weight (MW) polyol is in the range of 1 to 25 wt%, more preferably 2 to 20 wt%, based on the total weight of the isocyanate-reactive composition.

In embodiments, the amount of trimerization catalyst compound(s) is at least 75 wt%, preferably at least 90 wt%, based on the total weight of all catalyst compounds in the catalyst composition.

In embodiments, the polyisocyanate compounds are selected from toluene diisocyanate, methylene diphenyl diisocyanate, or a polyisocyanate composition comprising methylene diphenyl diisocyanate or a mixture of such polyisocyanates.

According to embodiments, the one or more isocyanate-reactive compounds in the reaction mixture further comprise monools and/or polyols that have an average nominal hydroxyl functionality of 1-8 and a number average molecular weight in the range of 200-8000 g/mol, and mixtures of said monools and/or or polyols such as (polyether)polyols and (polyether)polyols, mercaptans, carboxylic acids such as polybasic acids, amines, polyamines.

In embodiments, the blowing agent is selected from water, isobutene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFOs), and/or hydrocarbons, and is present in an amount of from 0.1 up to 80 parts by weight (pbw), preferably from 0.2 to 60 pbw, based on one hundred parts by weight of one or more isocyanate-reactive compounds.

According to a second aspect, a method is disclosed for making a polyisocyanurate-containing rigid foam material having a density in the range of 50-500 kg/m ³ , wherein said method provides a period between mixing of the components and the transition to a creamy mass of >35 seconds and the ability of instant curing and includes combining and mixing at isocyanate index at least 200 components of the reaction mixture according to the first aspect to obtain a foam.

In embodiments, the period between mixing the ingredients and going creamy is > 45 seconds, more preferably > 55 seconds, and instant cure time is < 110 seconds, preferably < 90 seconds, more preferably < 70 seconds.

In embodiments, the isocyanate index is greater than 220, preferably greater than 250.

According to a third aspect, a polyisocyanurate-containing material obtained by the method according to the second aspect is disclosed.

According to embodiments, the polyisocyanurate-containing material according to the invention has a free foam density (measured according to ISO 845) in the range of 50 kg/m ³ to 500 kg/m ³ , preferably in the range of 75 kg/m ³ to 300 kg/m ³ . more preferably in the range from 100 kg/m ³ to 200 kg/m ³ .

According to a fourth aspect, the use of a polyisocyanurate-containing material according to the invention in composite honeycomb structures is disclosed.

The independent and dependent claims set forth specific and preferred features of the invention. Features from dependent claims may be combined with features from independent or other dependent claims, as needed.

The above and other characteristics, features and advantages of the present invention will become apparent on the basis of the following detailed description. This description is given solely by way of example, without limiting the scope of the present invention.

DEFINITIONS AND TERMS

In the context of the present invention, the following terms have the following meanings:

1) "isocyanate index" or NCO index or index:

the ratio of NCO groups to isocyanate-reactive hydrogen atoms present in the composition, given as a percentage:

[NCO] x 100 (%).

[active hydrogen]

In other words, the NCO index expresses the percentage of isocyanate actually used in the composition relative to the amount of isocyanate theoretically required to react with the amount of isocyanate-reactive hydrogen used in the composition.

It should be noted that the isocyanate index in the context of this document is considered in terms of obtaining material during the actual polymerization process with the participation of the isocyanate ingredient and isocyanate-reactive ingredients. Any isocyanate groups consumed in a pre-stage to form modified polyisocyanates (including such isocyanate derivatives referred to in the art as prepolymers), or any reactive hydrogens consumed in a pre-stage (for example, reacted with an isocyanate to form modified polyols or polyamines) are not taken into account when calculating the isocyanate index. Only free isocyanate groups and free isocyanate-reactive hydrogens (including water hydrogens, if used) present in the actual polymerization step are taken into account.

2) The expression "isocyanate-reactive compounds" or "isocyanate-reactive hydrogen atoms", as used herein for purposes of calculating the isocyanate index, refers to all active hydrogen atoms in the hydroxyl and amine groups present in isocyanate-reactive compounds; this means that for the purposes of calculating the isocyanate index in an actual polymerization process, one hydroxyl group is considered to contain one reactive hydrogen, one primary amino group is considered to contain one reactive hydrogen, and one water molecule is considered to contain two reactive hydrogens.

3) "Reaction system": a combination of compounds where the polyisocyanates are contained in one or more containers separate from the isocyanate-reactive components.

4) The term "average nominal hydroxyl functionality" (or "functionality" for short) is used herein to indicate the number average functionality (number of hydroxyl groups per molecule) of a polyol or polyol composition, assuming that it represents the number average functionality (number of active hydrogen atoms per molecule). molecule) of the initiator(s) used in their preparation, although in practice it is often slightly smaller due to terminal unsaturation.

5) The word "average" refers to number average unless otherwise noted.

6) "Trimerization catalyst" in the context of this document refers to a catalyst that can catalyze (facilitate) the formation of isocyanurate groups from polyisocyanates. This means that isocyanates can react with other isocyanates to form macromolecules with isocyanurate structures (polyisocyanurate=PIR). Reactions between isocyanates-polyols and between isocyanates-isocyanates (homopolymerization) can proceed simultaneously or sequentially, with the formation of macromolecules with urethane and isocyanurate structures (PIR-PUR).

7) "Polyisocyanurate-containing material" (foam) refers to a material composition comprising urethane and isocyanurate structures (PIR-PUR) obtained at an isocyanate index of 200 or higher, more preferably at an isocyanate index of higher than 220.

8) "Loose foam density" refers to the density measured on foam samples made under atmospheric conditions (in the presence of blowing agents) according to ISO 845.

9) "The period between the mixing of the components and the transition to a creamy mass" refers to the period of time required for the reaction mixture to go from a liquid state to a creamy state and then begin to foam (expand).

10) "Instant cure" or "quick cure" refers to a reduced or minimal difference between the time until the tack disappears and the period between the mixing of the components and the transition to a creamy mass. Curing time is often referred to as demoulding time. Time to Tack Loss (TFT) means the period of time from the start of curing to the point at which the outer surface layer of the foam loses its tackiness. It can be determined by pressing the polyethylene film against the surface and checking for any adherent material while removing the film.

DETAILED DESCRIPTION

The present invention will now be described with respect to specific embodiments.

It should be noted that the term "comprising" as used in the claims should not be interpreted as being limited to the means listed after it; it does not exclude other elements or steps. Thus, it should be construed as defining the presence of the established features, steps, or components that are listed, but it does not preclude the presence or addition of one or more other features, steps, or components, or combinations thereof. Thus, the scope of the expression "device comprising means A and B" should not be limited to devices consisting only of components A and B. This means that, with respect to the present invention, the only relevant components of the device are A and B.

Throughout the description of the invention, reference is made to "one embodiment" or "some embodiment". Such references indicate that the particular feature described in relation to this embodiment is included in at least one embodiment of the present invention. Thus, the occurrences of the phrases "in one embodiment" or "in some embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, although they could. In addition, specific features or characteristics may be combined in any suitable manner in one or more embodiments, as would be obvious to one of ordinary skill in the art.

It should be appreciated that while preferred embodiments and/or materials are contemplated to provide embodiments of the present invention, various modifications or changes may be made without departing from the scope and spirit of this invention.

The present invention relates to a reaction system that achieves both a long period between mixing the components and the transition to a creamy mass (> 35 seconds), and fast curing (instant curing ability). The invention further relates to a process for making polyisocyanurate-containing foams, more particularly for making polyisocyanurate-containing rigid foams for use in composite materials such as honeycombs, by using the reaction system of the present invention.

According to a first aspect of the invention, a reaction system is disclosed for making a polyisocyanurate-containing foam having a free foam density in the range of 50-500 kg/m ³ (measured according to ISO 845), wherein said reaction system comprises at least:

a polyisocyanate composition comprising one or more polyisocyanate compounds;

a catalyst composition comprising at least a trimerization catalyst compound in an amount of at least 50% by weight, based on the total weight of all catalyst compounds in the catalyst composition;

- an isocyanate-reactive composition comprising at least a low molecular weight (MW) polyol having an MW below 200 g/mol, in an amount of from 0.1 to 30% by weight, based on the total weight of the isocyanate-reactive composition ;

- one or more foaming agents containing at least 50 mol%. water, based on the total molar amount of blowing agents;

optionally, one or more surfactants, one or more flame retardants, one or more antioxidants, or combinations thereof;

where % wt. trimerization catalyst compounds is < 0.5% wt., based on the total weight of the catalyst composition+polyisocyanate composition.

According to embodiments, % wt. trimerization catalyst compounds is <0.5 wt%, preferably <0.45 wt%, more preferably <0.4 wt%, most preferably <0.35 wt%, based on the total weight of the catalyst composition+polyisocyanate compositions.

According to embodiments, % wt. trimerization catalyst compounds is <0.3% wt., based on the total weight of the catalyst composition+polyisocyanate composition.

In embodiments, the low molecular weight (MW) polyol has a molecular weight below 200 g/mol, preferably below 150 g/mol, more preferably below 100 g/mol.

An advantage of the reaction mixture of the present invention is that it can be used to achieve both a long period between mixing of the components and transition to a creamy mass, and a short curing time, including the formation of polyisocyanurate (PIR). This combined effect results in reduced cycle times, for example in composite applications.

According to embodiments, the catalyst composition contains at least a trimerization catalyst compound in an amount of at least 75% by weight, more preferably in an amount of at least 90% by weight, based on the total weight of the compounds of all catalysts in catalyst composition.

According to a preferred embodiment of the first aspect of the invention, the trimerization catalyst is selected from organic salts, preferably alkali metal, alkaline earth metal and/or quaternary ammonium organic salts. More preferably, said organic salt is selected from carboxylates or alkoxides and mixtures thereof, a carboxylate/alkoxide group preferably having 1-12 carbon atoms, and mixtures thereof. Preferred examples include potassium carboxylates, sodium carboxylates, potassium alkoxides and sodium alkoxides. Also carboxylates/alkoxides having ring structures such as sodium or potassium benzoate are suitable trimerization catalysts. Most preferred examples include potassium acetate, potassium hexanoate, potassium ethylhexanoate, potassium octanoate, potassium lactate, N-hydroxypropyl trimethyl ammonium octanoate, N-hydroxypropyl trimethyl ammonium formate, and mixtures thereof. Suitable catalysts are commercially available; examples include LB Catalyst from Huntsman or Dabco® ^K2097 from Air Products (including potassium acetate), and ^Dabco® K15 (including potassium octoate).

In embodiments, the low molecular weight (MW) polyol having an MW below 200 g/mol is present in the reaction mixture in an amount of 0.1 to 30 wt%, preferably 1 to 25 wt%, more preferably 2 up to 20% wt., based on the total weight of the isocyanate-reactive composition.

In embodiments, the one or more low molecular weight isocyanate-reactive compounds are selected from monools and/or polyols such as glycols. Suitable examples include monools selected from methanol, ethanol, propanol, butanol, phenol, cyclohexanol and (hydrocarbon) monools having a number average molecular weight up to 200 g/mol, such as aliphatic monools and (polyether) monools, and/or polyols selected from monoethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, trimethylol propane, sorbitol, glycerin, propanediol, butanediol, pentanediol, hexanediol, aromatic and/or aliphatic polyols, having a molecular weight <200, preferably <150 g/mol, more preferably <100 g/mol.

According to embodiments, the isocyanate-reactive composition further comprises, in addition to the low MW polyol, a high molecular weight polyol having a number average molecular weight of preferably 200-8000 and an average nominal functionality of preferably 1-8. Said high molecular weight polyol may be selected from (polyether)polyols, (polyester)polyols, mercaptans, carboxylic acids such as polybasic acids, amines, polyamines having an average nominal hydroxyl functionality of 1-8 and a number average molecular weight up to 8000 , and their mixtures. Examples of suitable polyols include ^Hoopol® F-1390 ((polyether)polyol from Synthesia) and ^Daltolac® R-166 ((polyether)polyol from Huntsman).

According to a second aspect of the invention, a method is disclosed for making a polyisocyanurate-containing foam using a reaction mixture according to the invention. Said method, in connection with the foregoing, includes combining and mixing the ingredients of the reaction mixture with an isocyanate index of at least more than 200, preferably with an isocyanate index of 220 or higher.

According to embodiments, the method for making a polyisocyanurate-containing foam according to the invention results in both a time between mixing of the components and transition to a creamy mass of >35 seconds, preferably >45 seconds, more preferably >55 seconds, and an instant curing ability of <110 seconds, preferably <90 seconds, more preferably <70 seconds.

There are many different prescriptions regarding the order of bringing into contact or combination of compounds necessary for the manufacture of polyisocyanurate-containing foam of the present invention. One skilled in the art will appreciate that varying the order in which the compounds are added is within the scope of the present invention.

In embodiments, the polyisocyanate compounds used in the reaction mixture for making the PIR-containing foam of the invention are selected from organic isocyanates containing a plurality of isocyanate groups, including aliphatic isocyanates such as hexamethylene diisocyanate, and more preferably aromatic isocyanates such as meta- and para -phenylene diisocyanate, toluene-2,4- and 2,6-diisocyanates, diphenylmethane-4,4'-diisocyanate, chlorophenylene-2,4-diisocyanate, naphthylene-1,5-diisocyanate, diphenylene-4,4'-diisocyanate, 4,4'-diisocyanate-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate and diphenyl(ether)diisocyanate, cycloaliphatic diisocyanates such as cyclohexane-2,4- and 2,3-diisocyanates, 1-methylcyclohexyl-2,4- and 2,6-diisocyanates and mixtures thereof, and bis-(isocyanatocyclohexyl-)methane and triisocyanates such as 2,4,6-triisocyanatotoluene and 2,4,4'-triisocyanatodiphenyl ether.

In embodiments, the polyisocyanate composition comprises mixtures of polyisocyanates, for example a mixture of isomers of toluene diisocyanates, such as commercially available mixtures of 2,4- and 2,6-isomers, and also a mixture of diisocyanates and higher functional polyisocyanates obtained by phosgenation of aniline/formaldehyde condensates . Such mixtures are well known in the art and include crude phosgenation products containing mixtures of methylene bridged polyphenyl polyisocyanates including diisocyanate, triisocyanate and higher functionality polyisocyanates along with any by-products of phosgenation.

Preferred polyisocyanate compositions of the present invention are polyisocyanate compositions wherein the polyisocyanate is an aromatic diisocyanate or higher functionality polyisocyanate in a specific crude blend of methylene bridged polyphenyl polyisocyanates containing diisocyanates, triisocyanates and higher functionality polyisocyanates. Methylene-bridged polyphenyl polyisocyanates (e.g., methylene diphenyl diisocyanate, abbreviated as MDI) are well known in the art and have the general formula I, where n is 1 or more and, in the case of crude mixtures, is an average value greater than 1. They are obtained by phosgenation of the corresponding mixtures of polyamines, obtained by the condensation of aniline and formaldehyde.

(I)

(I)

Other suitable polyisocyanate compositions may include isocyanate-terminated prepolymers made by reacting an excess of a higher functionality diisocyanate or polyisocyanate with a hydroxyl-terminated polyester or a hydroxyl-terminated polyether, and products obtained by reacting an excess of a diisocyanate or polyisocyanate greater than high functionality and a monomeric polyol or a mixture of monomeric polyols such as ethylene glycol, trimethylol propane or butane diol. One preferred class of isocyanate-terminated prepolymers are isocyanate-terminated prepolymers of green blends having methylene bridges of polyphenyl polyisocyanates containing diisocyanates, triisocyanates and higher functionality polyisocyanates.

In embodiments, the polyisocyanate compounds in the polyisocyanate composition are selected from toluene diisocyanate, methylene diphenyl diisocyanate, or a polyisocyanate composition containing methylene diphenyl diisocyanate or a mixture of such polyisocyanates.

In embodiments, the isocyanate index is greater than 200, preferably greater than 220, more preferably greater than 250. For example, the isocyanate index may be in the range of 200 to 1000, 200 to 600, or 200 to 400.

The use of reaction mixtures having an isocyanate index >200 (resulting in isocyanurate formulations), for example in the case of composite honeycomb structures, provides several advantages over reaction mixtures having an isocyanate index of about 100 (resulting in polyurethane compositions). For example, the amount of heat generated is typically high, resulting in lower mold temperatures needed to achieve resin curing (i.e., energy savings), high aromatic content in reaction mixtures having an isocyanate index >200 results in more good fire resistance to the final composites, and high crosslink density results in improved mechanical properties (higher Tg, ...).

In embodiments, the blowing agent is preferably water, used alone or in combination with alternative blowing agents. The alternative blowing agent may be selected from isobutene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFOs), and hydrocarbons such as pentane. The amount of blowing agent used may vary based on, for example, the intended use and application of the foam product and the desired stiffness and density of the foam. The blowing agent may be present in amounts of from 0.1 to 80 parts by weight (pbw), more preferably from 0.2 to 60 pbw, based on one hundred parts by weight of isocyanate-reactive compounds (polyol), including a proportion of the catalyst composition in total weight.

In embodiments, one or more urethane catalyst compounds may be added to the reaction mixture, if necessary, although the trimerization catalyst compound must be present in an amount of >50% by weight, based on the total weight of all catalyst compounds used. Suitable urethane catalysts for use in this invention include metal salt catalysts such as organotin compounds, and amine compounds such as triethylenediamine (TEDA), N-methylimidazole, 1,2-dimethylimidazole, N-methylmorpholine, N-ethylmorpholine, triethylamine, N, N'-dimethylpiperazine, 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, N-methyldicyclohexylamine, pentamethyldipropylenetriamine, N-methyl-N'-(2-dimethylamino )-ethyl-piperazine, tributylamine, pentamethyldiethylenetriamine, hexamethyltriethylenetetramine, heptamethyltetraethylenepentamine, dimethylaminocyclohexylamine, pentamethyldipropylenetriamine, triethanolamine, dimethylethanolamine, bis(dimethylaminoethyl)ether, tris(3-dimethylamino)propylamine, or acid-blocked derivatives thereof, and the like, and any mixture thereof, but not limited to.

The present invention further relates to a polyisocyanurate-containing foam made using the method according to the invention and using the reaction mixture disclosed in the present invention, and to the use of said foam, for example, in composite materials, such as fiber-reinforced honeycomb composite structures for automotive applications with fast cycle (trunk shelves, trunk floors, car showroom ceiling upholstery, pallets, semi-structural parts…).

According to embodiments, the polyisocyanurate-containing material according to the invention has a free foam density (measured according to ISO 845) in the range of 50 kg/m ³ up to 500 kg/m ³ , preferably in the range of 75 kg/m ³ to 300 kg/m ³ , more preferably in the range from 100 kg/m ³ to 200 kg/m ³ .

In preferred embodiments, a composite material is disclosed having composite honeycomb structures with a core layer comprising a polyisocyanurate-containing material made according to the invention.

According to embodiments, the reaction mixture of the present invention can be applied by spraying, after mixing the desired ingredients at the starting point, from a spray nozzle, for example, onto a honeycomb structure or into a mold.

According to embodiments, the polyisocyanurate-containing foam of the present invention can be used, for example, in honeycomb structures. The polyisocyanurate-containing foam of the present invention meets all the requirements, according to which it provides sufficient time for uniform spraying of the reaction mixture on a substrate, such as glass fiber or a precast honeycomb structure, and/or for introducing it into a heated mold, where it is then carried out curing, while it is preferred that the instant cure capability minimizes the cycle time.

EXAMPLES

Used chemicals

Hoopol ^® F-1390: (Polyester) polyol from Synthesia (OH number: 240 mg KOH/g)

^Daltolac® R-166: (Polyether) polyol from Huntsman (OH number: 165 mg KOH/g)

Tegostab ^® B8490: Silica surfactant from Evonik (OH number: 0 mg KOH/g)

LB Catalyst: Huntsman Potassium Acetate PIR Catalyst (OH number: 865 mg KOH/g, 48.2 wt% potassium acetate, 48.2 wt% MEG, 3.6 wt% water)

DETDA: Diethyltoluene diamine from Lonza (OH number: 630 mg KOH/g) used as a chain extender

^DABCO® 33LV: Gelation catalyst from Air Products (OH number: 560 mg KOH/g, 33 wt. % triethylenediamine (TEDA) in dipropylene glycol)

^Jeffcat® PMDETA: Pentamethyldiethylenetriamine, foaming catalyst from Huntsman (OH number: 0 mgKOH/g)

Glycerin: from Huntsman (OH number: 1826 mg KOH/g)

MEG: Monoethylene glycol from Sigma-Aldrich (OH number: 1808 mgKOH/g)

Black ^Repitan® 90655: carbon black dispersion in (polyether) polyol from REPI (OH number: 30 mg KOH/g)

IMR VP063235: Internal mold release aid from KVS Eckert & Woelk

S2085: ^Suprasec® 2085 from Huntsman (Polymeric MDI, NCO number: 30.5)

S5025: ^Suprasec® 5025 from Huntsman (Polymeric MDI, NCO number: 31.0)

Suprasec ^® and Daltolac ^® are trademarks of Huntsman Corporation or its affiliates and are registered in one or more, but not all, countries.

Examples 1-7 and Comparative Examples 1-2

All foams are prepared under bowl scale (~120 g) free rise foam conditions by mixing the polyol blend (pre-prepared) and isocyanate under high shear conditions using a Heidolph mixer (~4000 revolutions per minute (rpm)) for 10 seconds . The density of the foam is measured according to the ISO 845 test method.

Table 1 summarizes the amounts of ingredients used in pbw (parts by weight) for the manufacture of foams according to the present invention (examples 1-7) and for the manufacture of comparative foams (comparative examples 1-2).

Compared to Comparative Example 1 (no low MW polyol present), Examples 1 and 2 prove that the presence of increasing amounts of glycerol both prolongs the period between mixing the components and going into a creamy mass (55 seconds → 65 seconds → 70 seconds) and improves instant cure capability at reduced ∆t (45 seconds → 40 seconds → 40 seconds). In other words, instant cure capability is improved in the presence of glycerol while not reducing the time between mixing the components and going to creamy mass (i.e., while maintaining a long period between mixing the components and going to creamy mass (CT)).

A similar trend is noted when considering the sample of comparative example 2 and samples of examples 4, 5, 6 and 7, which contain increasing amounts of MEG (CT: 47 seconds → 67 seconds → 82 seconds → 87 seconds → 112 seconds; ∆t: 103 seconds → 83 seconds → 58 seconds → 28 seconds). The presence of MEG improves the ability to flash cure while not reducing the period between mixing the components and the transition to a creamy mass.

Comparison of Example 3 and Comparative Example 1 confirms that increasing both the amount of PIR catalyst and the low MW polyol (glycerol in this particular case) can allow a constant period between mixing of the components and transition to a creamy mass (55 seconds in this particular case) to be maintained. , i.e. no reduction) while at the same time dramatically improving the instant cure capability (∆t drops from 45 seconds to 25 seconds).

All of these examples therefore provide evidence that the presence of both a PIR catalyst and a low MW polyol can maintain a long time between mixing and creaming (>35 seconds) and improve instant cure capability (reduced ∆t) .

Chemical Substance (pbw) Ref. Etc. one Ex 1 Ex 2 Ex 3 Ref. Etc. 2 Ex 4 Ex 5 Ex 6 Ex 7 Hoopol
F-1390 98.23 98.23 98.23 98.23 52.2 52.2 52.2 52.2 52.2 Water one one one one one one one one one Tegostab
B8490 1.77 1.77 1.77 1.77 1.77 1.77 1.77 1.77 1.77 Catalyst LB one one one 1.25 one one one one one DETDA four four four four four four four four four Glycerol - 2 3 3 - - - - - MEG - - - - - 2 5 ten fifteen Black Repitan 90655 - - - - four four four four four IMR VP063235 - - - - 7.5 7.5 7.5 7.5 7.5 S2085 231.47 231.47 231.47 231.47 - - - - - S5025 - - - - 270 270 270 270 270 % wt. trimerization catalyst compound(s) relative to compounds of all catalysts ^(*) 100 100 100 100 100 100 100 100 100 % wt. trimerization catalyst compounds relative to +isocyanate compounds ^(**) 0.208 0.208 0.208 0.260 0.178 0.178 0.178 0.178 0.178 Isocyanate index 284 256 244 243 502 432 357 277 226 Density (kg/m ³ ) 122.4 131.8 130.7 136 136 131.2 127.5 96.6 122.4 The period between mixing the components and the transition to a creamy mass (CT) (s) 55 65 70 55 47 67 82 87 112 Time to Touch Disappearance (TFT) (s) 100 105 110 80 150 150 140 115 140 ( EOR ) (With) 130 140 143 120 285 230 205 170 160 Δt (s)
(TFT-CT) 45 40 40 25 103 83 58 28 28

Table 1

(*) Amount (wt %) of trimerization catalyst compounds based on the total weight of all catalyst compounds.

(**) Amount (wt %) of trimerization catalyst compounds based on the total weight of all trimerization catalyst+isocyanate compounds.

Examples 8-14 and Comparative Examples 3-4

Use the same way to obtain foam, as for examples 1-7 and comparative examples 1-2.

Table 2 summarizes the amounts of ingredients used in pbw (in parts by weight) for the manufacture of foams according to the present invention (examples 8-14) and for the manufacture of comparative foams (comparative examples 3-4).

Comparative Examples 3 and 4 show that while the flash cure property improves (∆t reduced from 365 seconds to 166 seconds) with increasing amount of PIR catalyst, in the absence of a low MW polyol, the time between mixing the components and going to creamy mass (CT) also significantly reduced (from 55 seconds to 32 seconds), which is not desirable. In Example 11, the presence of glycerol and the presence of a higher amount of PIR catalyst made it possible to achieve the same CT (58 seconds) as in Comparative Example 3 (55 seconds) while achieving a much faster cure (∆t=57 seconds compared to 365 seconds).

Compared to Comparative Example 4 (no low MW polyol present), Examples 8, 9, 10, 11 and 12 confirm that the presence of increasing amounts of glycerol both prolongs the period between mixing the components and going into a creamy mass (32 seconds → 38 seconds → 42 sec → 48 sec → 58 sec → 65 sec) and improves instant cure ability with ∆t reduction (166 sec → 107 sec → 73 sec → 52 sec → 57 sec → 50 sec). In other words, the instant cure capability is improved in the presence of glycerol while not reducing the period between mixing the components and going to creamy mass (ie, while maintaining a long period between mixing the components and going to creamy mass).

A similar trend is noted when evaluating the sample of Comparative Example 4 and the samples of Examples 13 and 14, which contain increasing amounts of MEG (period between mixing the components and turning into a creamy mass: 32 seconds → 40 seconds → 45 seconds; ∆t: 166 seconds → 40 seconds → 20 seconds). The presence of MEG improves the ability to flash cure while not reducing the period between mixing the components and the transition to a creamy mass.

All of these examples thus confirm that the presence of both a PIR catalyst and a low MW polyol allows for a long period between mixing and creaming (>35 seconds) and improved instant set capability (reduced ∆t).

The use of polyesters (eg Hoopol ^® F-1390) or polyethers (eg Daltolac ^® R 166) does not interfere with PIR catalyst and/or low MW polyol trends in foam kinetics and flash cure capability.

Chemical Substance (pbw) Ref. Etc. 3 Ref. Etc. four Etc. eight Etc. 9 Etc. ten Etc. eleven Etc. 12 Etc. 13 Etc. fourteen Daltolac
R166 72.2 72.2 72.2 72.2 72.2 72.2 72.2 72.2 72.2 Water one one one one one one one one one Tegostab
B8490 1.77 1.77 1.77 1.77 1.77 1.77 1.77 1.77 1.77 Catalyst LB 0.3 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 DETDA four four four four four four four four four Glycerol - - 2 5 7.5 9 ten - - MEG - - - - - - - ten fifteen Black Repitan 90655 four four four four four four four four four IMR VP063235 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 S5025 250 250 250 250 250 250 250 250 250 Isocyanate index 492 488 416 341 297 275 262 263 212 % wt. trimerization catalyst compound(s) relative to compounds of all catalysts ^(*) 100 100 100 100 100 100 100 100 100 % wt. trimerization catalyst compounds relative to +isocyanate compounds ^(**) 0.058 0.096 0.096 0.096 0.096 0.096 0.096 0.096 0.096 Density (kg/m ³ ) 160.4 140.6 132.3 106.1 106.5 112.2 98.3 103.5 93.2 The period between mixing the components and the transition to a creamy mass (CT) (s) 55 32 38 42 48 58 65 40 45 Time to Touch Disappearance (TFT) (s) 420 198 145 115 100 115 115 80 65 ( EOR ) (With) 360 270 175 160 130 145 150 105 85 Δt (s)
(TFT-CT) 365 166 107 73 52 57 fifty 40 twenty

table 2

(*) Amount (wt %) of trimerization catalyst compounds based on the total weight of compounds of all catalysts.

(**) Amount (wt %) of trimerization catalyst compounds based on the total weight of all trimerization catalyst+isocyanate compounds.

Example 10 and Comparative Examples 5-10

Use the same way to obtain foam, as for examples 1-7 and comparative examples 1-2.

Table 3 summarizes the amounts of ingredients used in pbw (in parts by weight) for the manufacture of foams according to the present invention (example 10) and for the manufacture of comparative foams (comparative examples 5-10).

Example 10 is the same example as illustrated in Table 2.

Compared to Example 10, Comparative Examples 5, 6, 7, 8, 9, and 10 provide confirmation that the presence of large amounts of polyurethane gel and foam catalysts reduces the time between mixing the components and going into a creamy mass to well below 35 seconds, with this also degrades the ability to instant curing (comparative examples 6, 7, 9 and 10).

Chemical Substance (pbw) Etc. ten Ref. Etc. 5 Ref. Etc. 6 Ref. Etc. 7 Ref. Etc. eight Ref. Etc. 9 Ref. Etc. ten Daltolac R 166 72.2 72.2 72.2 72.2 72.2 72.2 72.2 Water one one one one one one one Tegostab B 8490 1.77 1.77 1.77 1.77 1.77 1.77 1.77 DETDA four four four four four four four Catalyst LB 0.5 0.5 0.17 0.08 0.5 0.17 0.08 Glycerol 7.5 7.5 2.5 1.25 7.5 2.5 1.25 PMDETA - 0.2 0.07 0.03 0.2 0.07 0.03 33LV - 1.5 0.5 0.25 4.5 1.5 0.75 Black Repitan 90655 four four four four four four four IMR VP063235 7.5 7.5 7.5 7.5 7.5 7.5 7.5 % wt. trimerization catalyst compound(s) relative to compounds of all catalysts ^(*) 100 25.7 25.9 25.2 12.5 12.7 12.0 S5025 250 250 250 250 250 250 250 % wt. trimerization catalyst compounds relative to +isocyanate compounds ^(**) 0.096 0.096 0.033 0.015 0.096 0.033 0.015 Isocyanate index 297 290 402 445 277 393 439 Density (kg/m ³ ) 106.5 147.4 180.7 234.3 150.8 168.3 174.2 CT (s) 48 9 fifteen 22 7 12 19 TFT(s) 100 60 840 2400 45 360 1200 EOR (With) 130 37 115 215 35 70 140 Δt (s) (TFT-CT) 52 51 825 2378 38 348 1181

Table 3

(*) Amount (wt %) of trimerization catalyst compounds based on the total weight of compounds of all catalysts.

(**) Amount (wt %) of trimerization catalyst compounds based on the total weight of all trimerization catalyst+isocyanate compounds.

Example 3 and Comparative Examples 11-13

Use the same way to obtain foam, as for examples 1-7 and comparative examples 1-2.

Table 4 summarizes the amounts of ingredients used in pbw (in parts by weight) for the manufacture of foams according to the present invention (example 3) and for the manufacture of comparative foams (comparative examples 11, 12 and 13).

Example 3 is the same example as illustrated in Table 1.

Compared to Example 3, Comparative Examples 11, 12 and 13 provide confirmation that if the amount of PIR catalyst is too high (i.e., >0.5 wt%), despite the presence of glycerol, the period between mixing the components and the transition to a creamy mass is significantly reduced to a value below 35 seconds.

Chemical Substance (pbw) Ex 3 Ref. Etc. eleven Ref. Etc. 12 Ref. Etc. 13 Hoopol
F-1390 98.23 98.23 98.23 98.23 Water one one one one Tegostab
B8490 1.77 1.77 1.77 1.77 Catalyst LB 1.25 2.5 3.0 3.5 DETDA four four four four Glycerol 3 3 3 3 S2085 231.47 231.47 231.47 231.47 % wt. trimerization catalyst compound(s) relative to compounds of all catalysts ^(*) 100 100 100 100 % wt. trimerization catalyst compounds relative to +isocyanate compounds ^(**) 0.260 0.518 0.621 0.724 Isocyanate index 243 236 233 231 Density (kg/m ³ ) 136 109 104 104 The period between mixing the components and the transition to a creamy mass (s) 55 33 thirty 25 Tack free time (s) 80 45 40 thirty EOR (With) 120 70 55 fifty Δt (s)
(TFT-CT) 25 12 ten 5

Table 4

(*) Amount (wt %) of trimerization catalyst compounds based on the total weight of all catalyst compounds.

(**) Amount (wt %) of trimerization catalyst compounds based on the total weight of all trimerization catalyst+isocyanate compounds.

Claims (24)

1. The reaction mixture for the manufacture of polyisocyanurate (PIR)-containing foam having a density in the range of 50-500 kg/m ³ where said reaction mixture has an isocyanate index of at least 200 and contains at least a polyisocyanate composition comprising one or more polyisocyanate compounds; - a catalyst composition comprising at least a trimerization catalyst compound in an amount of at least 50 wt. based on the total weight of the compounds of all catalysts in the catalyst composition; - an isocyanate-reactive composition comprising at least a low molecular weight (MW) polyol having an MW below 200 g/mol, in an amount of from 0.1 up to 30% of the mass. based on the total weight of the isocyanate-reactive composition; - one or more foaming agents containing at least 50 mol%. water based on the total molar amount of all blowing agents; where % wt. trimerization catalyst compounds is < 0.5% wt. based on the total weight of the compounds of the trimerization catalyst and polyisocyanate composition. 2. The reaction mixture according to claim 1, optionally containing one or more surfactants, one or more flame retardants, one or more antioxidants, or combinations thereof. 3. The reaction mixture according to claim 1, where the trimerization catalyst compound is selected from organic salts, preferably from organic alkali metal, alkaline earth metal and/or quaternary ammonium salts, such as potassium acetate, potassium hexanoate, potassium ethylhexanoate, potassium octanoate, potassium lactate, N-hydroxypropyl-trimethyl-ammonium octanoate, N-hydroxypropyl-trimethyl-ammonium formate, and mixtures thereof. 4. The reaction mixture according to any one of paragraphs. 1-3, wherein the low molecular weight (MW) polyol has a molecular weight below 150 g/mol, preferably below 100 g/mol. 5. The reaction mixture according to any one of paragraphs. 1-4 wherein the low molecular weight (MW) polyol is selected from glycerol and/or ethylene glycol. 6. The reaction mixture according to any one of paragraphs. 1-5, where the amount of polyol low molecular weight (MW) is in the range from 1 to 25% wt., more preferably from 2 to 20% of the mass. based on the total weight of the isocyanate-reactive composition. 7. The reaction mixture according to any one of paragraphs. 1-6, where the amount of compounds of the catalyst trimerization is at least 75% wt., preferably at least 90% of the mass. based on the total weight of the compounds of all catalysts in the catalyst composition. 8. The reaction mixture according to any one of paragraphs. 1-7, where the polyisocyanate compounds are selected from toluene diisocyanate, methylene diphenyl diisocyanate or a polyisocyanate composition comprising methylene diphenyl diisocyanate or a mixture of such polyisocyanates. 9. The reaction mixture according to any one of paragraphs. 1-8, wherein the one or more isocyanate-reactive compounds further comprise(s) monools and/or polyols which have an average nominal hydroxyl functionality of 1-8 and a number average molecular weight in the range of 200-8000 g/mol, and mixtures of said monools and/or polyols such as (polyether)polyols and (polyester)polyols, mercaptans, carboxylic acids such as polybasic acids, amines, polyamines. 10. The reaction mixture according to any one of paragraphs. 1-9, wherein the blowing agent further comprises isobutene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydro(chloro)fluoroolefins (HFOs/HCFOs) and/or hydrocarbons in addition to water. 11. A method for producing a polyisocyanurate-containing rigid foam having a density in the range of 50-500 kg/m ³ , wherein said method provides a period between mixing of the components and the transition to a creamy mass of > 35 seconds and an instant cure capability, defined as the difference between the time to tack disappearance and the period between mixing the components and the transition to a creamy mass, less than 110 seconds, and includes combining and mixing at an isocyanate index of at least 200 components of the reaction mixture according to any one of paragraphs. 1-10 to obtain foam. 12. The method according to claim 11, wherein the period between mixing the components and the transition to a creamy mass is > 45 seconds, more preferably > 55 seconds, and the ability to instant curing < 90 seconds, more preferably < 70 seconds. 13. The method according to any one of paragraphs. 11, 12, where the isocyanate index is above 220, preferably above 250. 14. The method according to any one of paragraphs. 11-13, where % wt. trimerization catalyst compounds is preferably <0.45% wt., more preferably <0.40% wt., most preferably <0.35% wt. based on the total weight of the compounds of the trimerization catalyst and polyisocyanate composition. 15. The method according to any one of paragraphs. 11-14, where % wt. compounds of the catalyst trimerization is <0.30% of the mass. based on the total weight of the compounds of the trimerization catalyst and polyisocyanate composition. 16. Polyisocyanurate-containing material obtained by the method according to any one of paragraphs. 11-15. 17. A polyisocyanurate-containing material according to claim 16 having a free foam density in the range of 75 kg/m ³ up to 300 kg/m ³ , more preferably in the range of 100 kg/m ³ to 200 kg/m ³ . 18. Use of a polyisocyanurate-containing material according to claim 17 in composite honeycomb structures. 19. A composite material having a composite honeycomb structure with a core layer comprising a polyisocyanurate-containing material according to any one of paragraphs. 16, 17.