Polyisocyanurate prepregs and fibre composite components produced therefrom

Abstract

The present invention relates to polyisocyanate compositions comprising two different types of polyisocyanates, their use in the manufacture of prepregs, and polyisocyanurate composites made from said prepregs.

Description

[Technical field]

[0001] The present invention relates to polyisocyanate compositions comprising two different types of polyisocyanates, their use in the manufacture of prepregs, and polyisocyanurate composites made from said prepregs. [Background technology]

[0002] Composite materials reinforced with fibers such as carbon fiber and glass fiber have been attracting attention due to their characteristics, namely, good heat resistance and good mechanical strength while being lightweight. They are being used more widely in various structural applications such as printed circuit boards, chassis, and various components of automobiles and aircraft. As a molding method for such fiber-reinforced resin composites, a method using an intermediate material called prepreg is widely used. In prepreg, the reinforcing fibers are impregnated with a thermosetting resin. The impregnated fibers are then cured and molded by autoclave molding or press molding.

[0003] Typically, prepreg resins are required to be both storage stable at room temperature and curable by heating or the like. A further desired feature is the possibility to cut the prepreg to size without the cutting tool being contaminated with the often sticky matrix material. Generally, thermosetting resins such as epoxy resin compositions are often used. However, prepregs containing epoxy resins have the disadvantage that they must be stored at low temperatures, since the curing has already progressed at room temperature. Prepregs based on epoxy systems and composite components produced therefrom are described, for example, in EP 0 981 427.

[0004] In recent years, polyurethane-based prepregs have also been developed that are characterized by storage stability at room temperature. Unlike prepregs based on epoxy resins, storage-stable PU prepregs do not need to be cooled in costly ways before processing. DE10200900193.3 and DE102009001806.9 describe a method for producing a storage-stable prepreg that essentially consists of A) at least one fibrous support and B) at least one reactive polyurethane composition in powder form as matrix material.

[0005] One of the largest application areas of epoxy-based prepregs is for producing copper clad laminates (CCLs) and printed circuit boards (PCBs). Although the above polyurethane-based prepregs can solve the problem of storage stability of prepregs, their dielectric properties cannot meet the comprehensive requirements for high-frequency signal transmission due to their high dielectric constant (Dk) and dissipation factor (Df). This is due to the large amount of polar urethane groups in the final cured resin. Especially in the high-frequency (above 2GHz) communication field such as radio frequency base stations and radar antennas, high requirements are set for signal transmission loss and signal transmission delay. Another barrier of polyurethane prepreg application for PCBs is their low heat resistance, for example, the glass transition temperature of PU-based prepregs reported in WO2012 / 038105 is only about 70°C Tg, and in WO2013 / 139704, the Tg of the final cured resin is 146°C, both of which are too low to meet the requirements of PCBs, which are usually above 150°C. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] EP0981427 [Patent Document 2] DE10200900193.3 [Patent Document 3] DE102009001806.9 [Patent Document 4] WO2012 / 038105 [Patent Document 5] WO2013 / 139704 Summary of the Invention

[0007] The object of the present invention is to provide a prepreg that can be produced by a simple process and has storage stability for several weeks at room temperature. The prepregs are further intended to be substantially tack-free so that they can be easily further processed. Another object of the present invention is to provide a resin composition that allows for obtaining printed wiring boards with low dielectric constant and high glass transition temperature.

[0008] Polyisocyanurate materials based on a dual curing mechanism are described. WO2018 / 087395 discloses the combination of acrylates and polyisocyanates so that two different crosslinking mechanisms are available that can be activated by different mechanisms, ionizing radiation and heat. WO2020 / 152107 discloses the use of polyisocyanates with small amounts of polyols or polyamines. In a first step, urethane or urea groups are formed by a first catalyst at a lower temperature. This reaction is limited by the number of available amine or hydroxyl groups. In a second step, a higher temperature is used to form isocyanurate groups from the remaining isocyanate groups.

[0009] Both mechanisms can be used to provide prepregs, however, in both cases one must accept that the resulting material will contain a significant amount of crosslinking groups other than isocyanurate groups, which may be undesirable depending on the application since isocyanurate groups have particularly advantageous properties.

[0010] The problem underlying the present invention is therefore the provision of a two-stage curing scheme which allows the production of polyisocyanurate plastics in two different curing steps, such that a storage-stable semi-finished product can be obtained in a first curing step and fully cured in a second curing step.

[0011] This problem is solved by the embodiments defined in the claims and the following description.

[0012] In a first embodiment, the present invention provides a polymerizable composition that is free of isocyanate-reactive groups or has an isocyanate component with a molar ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0:1.0, comprising: a) at least one aliphatic polyisocyanate; b) at least one cycloaliphatic polyisocyanate; and c) at least one trimerization catalyst; Including, wherein the concentration of the alicyclic polyisocyanate is 25% by weight to 75% by weight based on the total mass of all polyisocyanates present in the polymerizable composition; and wherein the concentration of the uretdione-forming catalyst in the composition is 10% by weight or less of the total mass of the uretdione-forming catalyst and the trimerization catalyst present in the polymerizable composition; The present invention relates to the composition.

[0013] A "polymerizable composition" is a composition comprising the components defined above and, optionally, further components described below, in which the components are mixed in such a way that the composition can be used to form a polymer by simple heating.

[0014] The polymerizable composition of the present invention is particularly suitable for the manufacture of prepreg materials. Prepreg materials are materials that contain thermosetting polymers that are partially cured so that the material can be handled or transported. However, the curing during the manufacture of the prepreg must not proceed to the point where the material becomes too hard and brittle to be processed, for example, by bending. In the polymerizable composition of the present invention, this is achieved by the combination of at least two different polyisocyanates with different reactivities. Thus, a first curing step at a lower temperature creates the prepreg mainly by crosslinking the isocyanate groups of the more reactive polyisocyanate, and then a second curing step can be used to obtain a hard, fully cured material that is suitable for the intended application. Of the above polyisocyanates, aromatic polyisocyanates have the highest reactivity, araliphatic polyisocyanates have the second highest reactivity, aliphatic polyisocyanates have the second lowest reactivity, and cycloaliphatic polyisocyanates are the least reactive species. Therefore, to achieve the two-stage curing mechanism desired by the present invention, the aliphatic polyisocyanate must be paired with at least one polyisocyanate having a different reactivity. Species that meet this requirement are cycloaliphatic, aromatic and araliphatic polyisocyanates. If the combination of an aliphatic polyisocyanate with a slower curing species is desired, it should be mixed with at least one cycloaliphatic polyisocyanate. If the combination of an aliphatic polyisocyanate with a faster curing species is desired, it should be mixed with at least one araliphatic and / or aromatic polyisocyanate. It is also possible to combine an aliphatic polyisocyanate with both faster curing and slower curing polyisocyanates. In a preferred embodiment of the present invention, the polymerizable composition comprises at least one aliphatic polyisocyanate and at least one cycloaliphatic polyisocyanate.

[0015] It is preferred that the at least one aliphatic polyisocyanate constitutes 10% to 80% by weight, preferably 25% to 65% by weight, of the total amount of all polyisocyanates present in the polymerizable composition.

[0016] The content of the alicyclic polyisocyanate is preferably 25% by weight to 75% by weight, and more preferably 30% by weight to 70% by weight.

[0017] In a preferred embodiment of the present invention, araliphatic and aromatic polyisocyanates constitute no more than 10% by weight, more preferably no more than 5% by weight, of the total amount of all polyisocyanates present in the polymerizable composition. Most preferably, the polymerizable composition is free of the aforementioned polyisocyanates.

[0018] The polymer obtained by polymerizing the polymerizable composition of the present invention enjoys its advantageous properties very substantially through crosslinking between isocyanate groups. It is therefore essential for the present invention that the ratio of isocyanate groups to the total amount of isocyanate reactive groups in the polymerizable composition is limited so that there is a clear molar excess of isocyanate groups. The molar ratio of isocyanate groups to isocyanate reactive groups of the isocyanate component in the reactive resin is consequently at least 2.0:1.0, preferably at least 3.0:1.0, more preferably at least 4.0:1.0, even more preferably at least 8.0:1.0. The composition may also be free of isocyanate reactive groups. "Isocyanate reactive groups" in the context of this application are hydroxyl, thiol, carboxyl and amino groups, amides, urethanes, acid anhydrides and epoxides.

[0019] In a preferred embodiment of the present invention, the polymerizable composition further comprises at least one organic solvent that does not contain isocyanate-reactive groups, also referred to as "inert solvent". Preferably, the concentration of this solvent is such that the viscosity of the polymerizable composition is between 100 mPas and 2,000 mPas. Typically, such a value is achieved when the polymerizable composition comprises preferably between 10% and 50% by weight of inert solvent, based on the sum of all polyisocyanates, all trimerization catalysts and all solvents.

[0020] In another preferred embodiment of the present invention, the polymerizable composition further comprises an organic or inorganic filler.

[0021] The term "polyisocyanate" as used herein is a general term for compounds containing two or more isocyanate groups in the molecule (this is understood by those skilled in the art to mean free isocyanate groups of the general structure -N=C=O). The simplest and most important representatives of these polyisocyanates are the diisocyanates. They have the general structure O=C=NRN=C=O, where R typically represents an aliphatic, cycloaliphatic and / or aromatic group. The "polyisocyanate component" refers to the totality of all polyisocyanates belonging to this genus. Thus, the term "aliphatic polyisocyanate component" refers to the sum of all aliphatic polyisocyanates present in the polymerizable composition, the term "aromatic polyisocyanate component" refers to all aromatic polyisocyanates, and the term "cycloaliphatic polyisocyanate component" refers to the sum of all cycloaliphatic polyisocyanates.

[0022] Due to their multifunctionality (≧2 isocyanate groups), it is possible to use the polyisocyanates to prepare a large number of polymers (e.g. polyurethanes, polyureas and polyisocyanurates) and low molecular weight compounds (e.g. those with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures).

[0023] The term "polyisocyanate" in this application also refers to monomeric and / or oligomeric polyisocyanates. However, in order to understand many aspects of the present invention, it is important to distinguish between monomeric and oligomeric polyisocyanates. When referring to an "oligomeric polyisocyanate" in this application, this is a compound that constitutes or contains a polyisocyanate formed from at least two monomeric diisocyanate molecules, i.e., a reaction product formed from at least two monomeric diisocyanate molecules.

[0024] The preparation of oligomeric polyisocyanates from monomeric diisocyanates is also referred to herein as modification of the monomeric diisocyanates, which "modification" as used herein means the reaction of monomeric diisocyanates with uretdiones, isocyanurates, allophanates, biurets, iminooxadiazinediones and / or oxadiazinetriones to give oligomeric polyisocyanates.

[0025] For example, hexamethylene diisocyanate (HDI) is a "monomeric diisocyanate" because it contains two isocyanate groups and is not the reaction product of at least two polyisocyanate molecules: [ka]

[0026] In contrast, a reaction product formed from at least two HDI molecules, and still having at least two isocyanate groups, is an "oligomeric polyisocyanate" within the context of the present invention. Representative examples of such "oligomeric polyisocyanates" start from monomeric HDI, such as HDI isocyanurates and HDI biurets, each of which is formed from three monomeric HDI units: [ka]

[0027] According to the invention, the proportion of isocyanate groups, based on the total amount of all polyisocyanates present in the polymerizable composition, is at least 15% by weight.

[0028] In principle, monomeric and oligomeric polyisocyanates are equally suitable for use in the present invention. Thus, any polyisocyanate can consist essentially of monomeric polyisocyanates or consist essentially of oligomeric polyisocyanates. Alternatively, it may comprise oligomeric and monomeric polyisocyanates in any desired mixing ratio.

[0029] However, in a preferred embodiment of the present invention, the polyisocyanate used as a reactant in the trimerization has a low level of monomer (i.e., a low level of monomeric diisocyanate) and already contains oligomeric polyisocyanates. If the monomer content of the polyisocyanate composition is too high, the first curing step will not result in a storage-stable semi-finished product. The expressions "having a low level of monomer" and "having a low level of monomeric diisocyanate" are used interchangeably herein.

[0030] Particularly practically relevant results are established when the polyisocyanates have a proportion of monomeric diisocyanates of 20% by weight or less, in particular 15% by weight or less or 10% by weight or less, based on the weight of the respective polyisocyanate. Preferably, the polyisocyanates have a content of monomeric diisocyanates of 5% by weight or less, preferably 2.0% by weight or less, more preferably 1.0% by weight or less, based on the weight of the respective polyisocyanate. Particularly good results are established when the polyisocyanates are essentially free of monomeric diisocyanates. "Essentially free" here means that the content of monomeric diisocyanates is 0.5% by weight or less, based on the weight of the polyisocyanate.

[0031] In a particularly preferred embodiment of the present invention, each isocyanate is composed entirely of at least 80% by weight, 85% by weight, 90% by weight, 95% by weight, 98% by weight, 99% by weight or 99.5% by weight of oligomeric polyisocyanate, based on the weight of the respective polyisocyanate, or to the extent of at least 80% by weight, 85% by weight, 90% by weight, 95% by weight, 98% by weight, 99% by weight or 99.5% by weight of oligomeric polyisocyanate. Here, a content of at least 99% by weight of oligomeric polyisocyanate is preferred. This content of oligomeric polyisocyanate relates to the polyisocyanate provided. In other words, the oligomeric polyisocyanate is not formed as an intermediate during any process of the present invention, but is already present in the polymerizable composition at the start of any reaction.

[0032] Polyisocyanate compositions having low levels of monomers or essentially free of monomeric isocyanates can be obtained by carrying out, after the actual modification reaction, in each case at least one further process step for removing the unconverted excess monomeric diisocyanates. This removal of the monomers can be carried out in a particularly practical manner by methods known per se, preferably by thin-film distillation under high vacuum or by extraction with suitable solvents which are inert towards isocyanate groups, for example aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane or cyclohexane.

[0033] In a preferred embodiment of the present invention, the polyisocyanate component of the present invention is obtained by modifying a monomeric diisocyanate, followed by removal of the unconverted monomer.

[0034] The oligomeric polyisocyanates according to the invention may in particular have uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures. In one embodiment of the invention, the oligomeric polyisocyanates have at least one of the following oligomeric structure types or mixtures thereof: [ka]

[0035] In a preferred embodiment of the present invention, an aliphatic polyisocyanate component is used, wherein the isocyanurate structure content of this component is at least 50 mol %, preferably at least 60 mol %, more preferably at least 70 mol %, even more preferably at least 80 mol %, even more preferably at least 90 mol %, and particularly preferably at least 95 mol %, based on the sum of oligomeric structures from the group consisting of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structures present in the aliphatic polyisocyanate component.

[0036] When a cycloaliphatic polyisocyanate component is present, it is also preferred that it has an isocyanurate structure content of at least 50 mol %, preferably at least 60 mol %, more preferably at least 70 mol %, even more preferably at least 80 mol %, even more preferably at least 90 mol %, and particularly preferably at least 95 mol %, based on the sum of oligomeric structures from the group consisting of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structures present in the cycloaliphatic polyisocyanate component.

[0037] In the research underlying the present invention, it was found that the use of oligomeric polyisocyanates containing isocyanurate groups improves the heat resistance of the final product.

[0038] The proportion of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures in the polyisocyanates can be determined, for example, by NMR spectroscopy, where it is possible to use preferably 13C NMR spectroscopy of the proton decoupled type, since the mentioned oligomeric structures give characteristic signals.

[0039] Regardless of the underlying oligomeric structure (uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures), the oligomeric polyisocyanates for use in the present invention preferably have an (average) NCO functionality of 2.0 to 5.0, preferably 2.3 to 4.5.

[0040] Results of particularly practical relevance are established if the respective polyisocyanates used according to the invention have a content of isocyanate groups of 8.0% by weight to 28.0% by weight, preferably 14.0% by weight to 25.0% by weight, based on the weight of the respective polyisocyanate.

[0041] Processes for the preparation of the oligomeric polyisocyanates having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures used according to the invention are described, for example, in J.Prakt.Chem. 336 (1994) 185-200, DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or EP-A 0 336 205, EP-A 0 339 396 and EP-A 0 798 299.

[0042] Since the beneficial effects of the present invention require the presence of different types of polyisocyanates, these types are defined in more detail below.

[0043] Aliphatic Polyisocyanates In aliphatic polyisocyanates, all of the isocyanate groups are attached to carbon atoms that are part of an open carbon chain, which may be unsaturated at one or more sites. The aliphatically bound isocyanate groups are preferably attached at the terminal carbon atoms of the carbon chain.

[0044] Aliphatic polyisocyanates which are particularly suitable according to the invention are 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane and 1,10-diisocyanatodecane and oligomers derived therefrom.

[0045] Alicyclic Polyisocyanate In cycloaliphatic polyisocyanates, all of the isocyanate groups are attached to carbon atoms that are part of a closed ring of carbon atoms. This ring may be unsaturated at one or more sites, as long as it does not acquire aromatic character as a result of the presence of a double bond.

[0046] Cycloaliphatic polyisocyanates which are particularly suitable according to the invention are 1,3- and 1,4-diisocyanatocyclohexane, 1,4-diisocyanato-3,3,5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate; IPDI), 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, Bis(isocyanatomethyl)norbornane (NBDI), 4,4'-diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethane, 4,4'-diisocyanato-1,1'-bi(cyclohexyl), 4,4'-diisocyanato-3,3'-dimethyl-1,1'-bi(cyclohexyl), 4,4'-diisocyanato-2,2',5,5'-tetramethyl-1,1'-bi(cyclohexyl), 1,8-diisocyanato-p-menthane, 1,3-diisocyanatoadamantane and 1,3-dimethyl-5,7-diisocyanatoadamantane and oligomers derived therefrom.

[0047] Aromatic Aliphatic Polyisocyanates In araliphatic polyisocyanates, all of the isocyanate groups are bonded to methylene groups which are in turn bonded to aromatic rings.

[0048] Particularly suitable araliphatic polyisocyanates according to the invention are 1,3- and 1,4-bis(isocyanatomethyl)benzene (xylylene diisocyanate; XDI), 1,3- and 1,4-bis(1-isocyanato-1-methylethyl)benzene (TMXDI) and bis(4-(1-isocyanato-1-methylethyl)phenyl)carbonate and oligomers derived therefrom.

[0049] Aromatic Polyisocyanates In aromatic polyisocyanates, all of the isocyanate groups are attached directly to carbon atoms that are part of an aromatic ring.

[0050] Aromatic polyisocyanates which are particularly suitable according to the invention are 2,4- and 2,6-diisocyanatotoluene (TDI), 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI) and 1,5-diisocyanatonaphthalene and the oligomers derived therefrom.

[0051] catalyst A "trimerization catalyst" as understood in the present application is a catalyst that catalyzes the addition of isocyanate groups to isocyanurate structures. The catalyst preferably converts no more than 20 mol %, more preferably no more than 10 mol %, and most preferably no more than 5 mol % of the isocyanate groups in the polymerizable composition into uretdione groups, since these groups are less stable and impair the chemical and physical properties of the material. Furthermore, the concentration of the uretdione-forming catalyst in the composition is preferably no more than 10 wt %, more preferably no more than 3 wt %, of the total mass of the uretdione-forming catalyst and the trimerization catalyst present in the polymerizable composition. Most preferably, the composition does not contain a uretdione-forming catalyst.

[0052] Suitable trimerization catalysts are, for example, simple tertiary amines, such as triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine or N,N'-dimethylpiperazine. Suitable catalysts also include tertiary hydroxyalkylamines, such as triethanolamine, N-methyldiethanolamine, dimethylethanolamine, N-isopropyldiethanolamine and 1-(2-hydroxyethyl)pyrrolidine, as described in GB 2 221 465, or the catalyst systems known from GB 2 222 161, which consist of mixtures of tertiary bicyclic amines, such as DBU, with low molecular weight simple aliphatic alcohols.

[0053] Further trimerization catalysts are, for example, the quaternary ammonium hydroxides known from DE-A 1 667 309, EP-A 0 013 880 and EP-A 0 047 452, such as tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, N,N-dimethyl-N-dodecyl-N-(2-hydroxyethyl)ammonium hydroxide, N-(2-hydroxyethyl)-N,N-dimethyl-N-(2,2'-dihydroxymethylbutyl)ammonium hydroxide and 1-(2-hydroxyethyl)-1,4-diazabicyclo[2.2.2]octane hydroxide (monoadduct of ethylene oxide and water to 1,4-diazabicyclo[2.2.2]octane), EP-A 37 65 or EP-A 10 quaternary hydroxyalkylammonium hydroxides known from DE-A 2 631 733, EP-A 0 671 426, EP-A 1 599 526 and US 4,789,705, such as N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium hydroxide, trialkylhydroxylalkylammonium carboxylates known from DE-A 2 631 733, EP-A 0 671 426, EP-A 1 599 526 and US 4,789,705, such as N,N,N-trimethyl-N-2-hydroxypropylammonium p-tert-butylbenzoate and N,N,N-trimethyl-N-2-hydroxypropylammonium 2-ethylhexanoate, EP-A 1 229 016, such as N-benzyl-N,N-dimethyl-N-ethylammonium pivalolate, N-benzyl-N,N-dimethyl-N-ethylammonium 2-ethylhexanoate, N-benzyl-N,N,N-tributylammonium 2-ethylhexanoate, N,N-dimethyl-N-ethyl-N-(4-methoxybenzyl)ammonium 2-ethylhexanoate or N,N,N-tributyl-N-(4-methoxybenzyl)ammonium pivalate, tetrasubstituted ammonium α-hydroxycarboxylates known from WO 2005 / 087828, such as tetramethylammonium lactate, quaternary ammonium or phosphonium fluorides known from EP-A 0 339 396, EP-A 0 379 914 and EP-A 0 443 167, such as N-methyl-N,N,N-trialkylammonium fluorides, such as N,N,N,N-tetra-n-butylammonium fluoride, N,N,N-trimethyl-N-benzylammonium fluoride, tetramethylphosphonium fluoride, tetraethylphosphonium fluoride or tetra-n-butylphosphonium fluoride, quaternary ammonium and phosphonium polyfluorides known from EP-A 0 798 299, EP-A 0 896 009 and EP-A 0 962 455, such as benzyltrimethylammonium polyhydrogen fluoride, tetraalkylammonium alkyl carbonates known from EP-A 0 668 271 and obtainable by reacting tertiary amines with dialkyl carbonates, or quaternary ammonio alkyl carbonates of betaine structure, quaternary ammonium hydrogen carbonates known from WO 1999 / 023128, such as choline bicarbonate, EP 0 102 482, quaternary ammonium salts obtained from alkylated esters of tertiary amines and phosphoric acid, examples of such salts being the reaction products of triethylamine, DABCO or N-methylmorpholine with dimethylmethanephosphonate, or tetrasubstituted ammonium salts of lactams, such as trioctylammonium caprolactamate or dodecyltrimethylammonium caprolactamate, known from WO 2013 / 167404.

[0054] Suitable salts are the known sodium and potassium salts of straight or branched chain alkanecarboxylic acids having up to 14 carbon atoms, such as butyric acid, valeric acid, caproic acid, 2-ethylhexanoic acid, heptanoic acid, caprylic acid, pelargonic acid and the higher homologues.

[0055] Also suitable as trimerization catalysts are a large number of different metal compounds. Suitable examples are the octanoates and naphthenates of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium or lead or mixtures thereof with the acetates of lithium, sodium, potassium, calcium or barium, which are described as catalysts in DE-A 3 240 613, the sodium and potassium salts of linear or branched alkanecarboxylic acids having up to 10 carbon atoms, such as propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid and undecylic acid, which are disclosed by DE-A 3 219 608, the alkali metal or alkaline earth metal salts of aliphatic, alicyclic or aromatic mono- or polycarboxylic acids having 2 to 20 carbon atoms, such as sodium benzoate or potassium benzoate, which are disclosed by EP-A 0 100 129, the sodium phenoxide or potassium phenoxide, which are disclosed by GB-A 1 391 066 and GB-A 1 386. 399, the alkali metal and alkaline earth metal oxides, hydroxides, carbonates, alkoxides and phenoxides disclosed in GB 809 809, the alkali metal salts of enolizable compounds and alkali metal salts of weakly aliphatic or cycloaliphatic carboxylic acids, such as sodium methoxide, sodium acetate, potassium acetate, sodium acetoacetate, lead 2-ethylhexanoate and lead naphthenate, basic alkali metal compounds complexed with crown ethers or polyether alcohols, such as complexed sodium or potassium carboxylates and / or pyrrolidinone potassium salts disclosed in EP-A 0 0 303 581, the application EP No. 13196508.9, such as zirconium tetra-n-butoxide, zirconium tetra-2-ethylhexanoate and zirconium tetra-2-ethylhexoxide, as well as the mono- or polynuclear complexes of titanium, zirconium and / or hafnium disclosed in European Polymer Journal, vol.16, 147-148 (1979), such as dibutyltin dichloride, diphenyltin dichloride, triphenylstannanol, tributyltin acetate, stannous octoate, dibutyl(dimethoxy)stannane, and tributyltin imidazolate.

[0056] Further trimerization catalysts suitable for the process of the present invention can be found, for example, in JH Saunders and KC Frasch, Polyurethanes Chemistry and Technology, p. 94 ff. (1962) and the references cited therein.

[0057] The trimerization catalysts can be used in the process according to the invention either individually or in the form of any desired mixtures with one another.

[0058] Also particularly suitable are the alkali metal or alkaline earth metal salts of aliphatic, cycloaliphatic or aromatic mono- and polycarboxylic acids having 2 to 20 carbon atoms. Even more preferred are the potassium salts of any of the abovementioned carboxylic acids. Potassium acetate is particularly preferred.

[0059] However, all catalysts described in WO2016 / 170057, WO2016 / 170059 or WO2016 / 170061 are in principle suitable, provided that they catalyze the crosslinking reaction in the abovementioned temperature range.

[0060] Particularly suitable as trimerization catalysts are the catalysts of formula (I) and their adducts. [ka]

[0061] [In the formula, R 1 and R 2are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl; A is O, S and NR 3 wherein R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl; and B is independently OH, SH, NHR 4 and NH2, where R 4 is selected from the group consisting of methyl, ethyl and propyl. In a preferred embodiment, A is NR 3 where R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl. 3 is preferably methyl or ethyl. 3 is particularly preferably methyl.

[0062] In a first variant of this embodiment, B is OH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0063] In a second variation of this embodiment, B is SH and R 1 and R 2are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0064] In a third variation of this embodiment, B is NHR 4 and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl. In this variant, R4 is selected from the group consisting of methyl, ethyl and propyl. It is preferred when R4 is methyl or ethyl. R4 is particularly preferably methyl.

[0065] In a fourth variation of this embodiment, B is NH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0066] In a more preferred embodiment, A is oxygen.

[0067] In a first variant of this embodiment, B is OH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0068] In a second variation of this embodiment, B is SH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0069] In a third variation of this embodiment, B is NHR 4 and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of one another, methyl or ethyl. 1 and R2 is particularly preferably methyl. In this variation, R 4 is selected from the group consisting of methyl, ethyl and propyl. It is preferred when R4 is methyl or ethyl. R4 is particularly preferably methyl.

[0070] In a fourth variation of this embodiment, B is NH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0071] In yet another preferred embodiment, A is sulfur.

[0072] In a first variant of this embodiment, B is OH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0073] In a second variation of this embodiment, B is SH and R 1 and R 2are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0074] In a third variation of this embodiment, B is NHR 4 and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl. In this variation, R 4 is selected from the group consisting of methyl, ethyl and propyl. It is preferred when R4 is methyl or ethyl. R4 is particularly preferably methyl.

[0075] In a fourth variation of this embodiment, B is NH and R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl. 1 and R 2 are preferably, independently of each other, methyl or ethyl. 1 and R 2 is particularly preferably methyl.

[0076] Also suitable are adducts of the compounds of formula (I) and compounds having at least one isocyanate group.

[0077] The generic term "adducts" is understood to mean urethane, thiourethane and urea adducts of compounds of formula (I) with compounds having at least one isocyanate group. Urethane adducts are particularly preferred. The adducts of the present invention are formed when an isocyanate reacts with the functional group B of the compound defined by formula (I). If B is a hydroxyl group, urethane adducts are formed. If B is a thiol group, thiourethane adducts are formed. If B is NH2 or NHR 4 When the formula is:

[0078] Suitable catalyst solvents are, for example, solvents which are inert towards isocyanate groups, such as, for example, hexane, toluene, xylene, chlorobenzene, ethyl acetate, butyl acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl or monoethyl ether acetate, diethylene glycol ethyl and butyl ether acetate, propylene glycol monomethyl ether acetate, 1-methoxy-2-propyl acetate, 3-methoxy-n-butyl acetate, propylene glycol diacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, lactones such as β-propiolactone, γ-butyrolactone, ε-caprolactone and ε-methylcaprolactone, and also N-methylpyrrolidone and N-methylcaprolactam, 1,2-propylene carbonate, methylene chloride, dimethylsulfoxide, triethylphosphate, or any desired mixtures of such solvents.

[0079] When a catalyst solvent is used in the polymerizable composition, it is preferable to use a catalyst solvent that has a group reactive with isocyanates and can be incorporated into the polyisocyanurate resin. Examples of such solvents are monohydric or polyhydric simple alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, n-hexanol, 2-ethyl-1-hexanol, ethylene glycol, propylene glycol, isomeric butanediols, 2-ethylhexane-1,3-diol or glycerol; ether alcohols, such as 1-methoxy-2-propanol, 3-ethyl-3-hydroxymethyloxetane, tetrahydrofurfuryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, ethylene glycol monoethyl ether, di ... or other liquid high molecular weight polyethylene glycols, polypropylene glycols, mixed polyethylene / polypropylene glycols and their monoalkyl ethers; ester alcohols, such as ethylene glycol monoacetate, propylene glycol monolaurate, glycerol mono- and diacetate, glycerol monobutyrate or 2,2,4-trimethylpentane-1,3-diol monoisobutyrate; unsaturated alcohols, such as allyl alcohol, 1,1-dimethylallyl alcohol or oleyl alcohol; araliphatic alcohols, such as benzyl alcohol; N-monosubstituted amides, such as N-methylformamide, N-methylacetamide, cyanoacetamide or 2-pyrrolidinone, or any desired mixture of such solvents.

[0080] solvent Suitable solvents must be inert towards isocyanate groups, i.e. they must not contain isocyanate-reactive groups as defined above in this application. The solvent is preferably selected from the group consisting of hexane, toluene, xylene, chlorobenzene, ethyl acetate, butyl acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl or monoethyl ether acetate, diethylene glycol ethyl and butyl ether acetate, propylene glycol monomethyl ether acetate, 1-methoxyprop-2-yl acetate, 3-methoxy-n-butyl acetate, propylene glycol diacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, lactones such as β-propiolactone, γ-butyrolactone, ε-caprolactone and ε-methylcaprolactone, N-methylpyrrolidone, N-methylcaprolactam, 1,2-propylene carbonate, methylene chloride, dimethylformamide, trichloroethylene, dimethylsulfoxide and triethyl phosphate. More preferably, at least one solvent is selected from the group consisting of butyl acetate.

[0081] Filler Any type of inorganic or inorganic filler known in the art can be used.Preferred inorganic fillers are selected from the group consisting of metal oxides, nitrites, silicides, especially silica, borides, especially boron nitride, wollastonite, talc, kaolin, clay, mica, alumina, zirconia, titania and mixtures thereof.Preferred organic fillers are selected from the group consisting of fluorine-based polymers, polystyrene-based polymers, divinylbenzene-based polymers, polyimide-based polymers, polyphenyl ether-based polymers, poly(triallyl isocyanurate)-based polymers and mixtures thereof.The organic and inorganic fibers described further below in this application are not fillers as understood in this paragraph.

[0082] Additives In addition, the polymerizable composition of the present invention may contain at least one additive selected from the group consisting of antioxidants, flame retardants, heat stabilizers, antistatic agents, UV absorbers, pigments, wetting agents, defoamers, colorants, lubricants, adhesion promoters, additional monomers, and compatibilizers. Preferred additional monomers are selected from the group consisting of styrene, vinyl toluene, t-butyl styrene, para-methyl styrene, diallyl phthalate, 2,4-ethylmethylimidazole, polyphenyl ether, triallyl isocyanurate, butadiene, isoprene, and 1,2-butadiene. Preferred compatibilizers are selected from the group consisting of styrene-butadiene block copolymers, styrene-isoprene block copolymers, 1,2-polybutadiene, 1,4-polybutadiene, maleic acid modified polybutadiene, acrylic acid modified polybutadiene, epoxy modified polybutadiene, and mixtures thereof.

[0083] Manufacturing method of semi-finished products In another embodiment, the present invention provides the following a) providing a polymerizable composition as defined above in this application; and b) curing the polymerizable composition at a temperature of 150°C to 200°C, thereby obtaining a semi-finished product. The present invention relates to a method comprising the steps of:

[0084] The term "providing a polymerizable composition" refers to a process that results in the polymerizable composition described above. Suitable methods are known in the art.

[0085] Curing in a method step results in a "semi-finished product", i.e. a material that can be further processed or transported, but which is still soft and flexible enough to be processed, for example by pressing into a mold.

[0086] In a preferred embodiment, process step b) is continued until the obtained polymer is tack-free.

[0087] In another preferred embodiment, process step b) is continued until 2% to 60% of the free isocyanate groups present at the start of process step b) have been consumed.

[0088] In yet another preferred embodiment, method step b) is continued until the polymerizable composition reaches a viscosity of 30,000 to 750,000 mPas, preferably 50,000 to 750,000 mPas, most preferably 100,000 to 750,000 mPas, the viscosity being preferably determined using a cone-and-plate viscometer at a temperature of 23° C. and a shear rate of 1 / s.

[0089] In a particularly preferred embodiment, method step b) comprises a step of ruthenium oxide having a modulus G′ of 5×10, determined by a plate-plate rheometer at 23° C. and a shear rate of 1 / s according to ISO 6721-10:2015-09. 3 This continues until Pa is reached.

[0090] If an inert organic solvent is present in the polymerizable composition, process step b) is preferably continued until at least 90% by weight of the organic solvent has evaporated, this criterion being preferably combined with one or more of the above defined criteria relating to the state of the polymer network.

[0091] In any case, it is preferred that at the end of process step b), at least 20%, preferably at least 30%, of the free isocyanate groups present at the start of process step b) are still present so that a second curing step is possible.

[0092] Method step b) is preferably carried out at a temperature of 150 ° C to 200 ° C for 1 to 20 minutes. The combination of temperature and duration for the first curing step depends on the geometric shape of the product, as well as on the type of polyisocyanate and catalyst present in the polymerizable composition used. This can be easily determined by simple preliminary experiments applying one of the preferred end points of method step b) described above.

[0093] Process step b) can be easily stopped by lowering the temperature to a temperature below 60°C, preferably below 40°C.

[0094] In a preferred embodiment of the polymerizable composition of the present invention, a fiber or a metal sheet is coated with the polymerizable composition provided in process step a) before starting process step b). The fiber may be any inorganic or organic fiber used in the art to manufacture composite materials. The fiber may have a size. The metal sheet is preferably a copper sheet.

[0095] Preferred inorganic fibers are glass fibers, basalt fibers, boron fibers, ceramic fibers, whiskers, silica fibers and metal-reinforced fibers. Preferred organic fibers are natural fibers, aramid fibers, carbon fibers, carbon nanotubes, polyester fibers, nylon fibers and plexiglass fibers. Preferred natural fibers are flax fibers, hemp fibers, wood fibers, cellulose fibers and sisal fibers.

[0096] If one or more fibres or one or more metal sheets are coated with the polymerizable composition before starting process step b), the semi-finished product resulting from process step b) is a so-called "prepreg", this term referring to a fibre or a number of fibres or metal sheets precoated with a partially cured polymerizable composition so that said fibres or fibres or metal sheets can be transported or processed.

[0097] The process of the invention results in particularly advantageous semi-finished products, since the crosslinking of the isocyanate groups by trimerization proceeds only at temperatures well above room temperature, so that the semi-finished products can be stored at room temperature for several weeks without losing the ability to be further processed.

[0098] In yet another embodiment, the present invention relates to a semi-finished product obtained or obtainable by the process of the present invention.

[0099] Method steps a) and b) result in a semi-finished product which can be sold, transported and further processed by the customer. In a preferred embodiment, said semi-finished product is a prepreg.

[0100] How to make a fully cured product In another preferred embodiment, the method according to the invention comprises an additional method step c) of hardening the semi-finished product, whereby the final product is obtained.

[0101] Process step c) preferably proceeds until at least 90% of the isocyanate groups originally present in the polymerizable composition at the start of process step b) have been consumed.

[0102] For method step c), temperatures between 200° C. and 250° C. are preferred. The preferred duration of method step c) is between 1 hour and 8 hours, more preferably between 2 hours and 6 hours.

[0103] It is preferred that method step c) is started 1 to 30 days, more preferably 3 to 14 days after method step b) has ended. Furthermore, it is preferred that the location where method step c) is performed is at least 1 km, more preferably at least 10 km away from the location where method step b) is performed, i.e. the semi-finished product is transported to a different location before the second curing step.

[0104] Process step c) results in a fully cured product.

[0105] In yet another embodiment, the present invention relates to an end product obtained or obtainable by the process of the present invention comprising the process steps a), b) and c) defined above.

[0106] Preferably the final product forms part of a laminate, a metal clad laminate or a printed circuit board, more preferably a copper clad laminate or a printed circuit board.

[0107] The final product is a polyisocyanurate plastic, i.e. a polymer whose crosslinking groups are mainly isocyanurate groups. Compared to other polymers, this product is characterized by excellent hardness and heat resistance. Moreover, it is inherently flame retardant, even without the addition of dedicated flame retardants.

[0108] The following examples are intended merely to illustrate the invention. They do not limit the scope of the claims in any way. EXAMPLES

[0109] Working Example In this experimental section, the currently common ambient temperature of 25° C. is referred to as room temperature (RT).

[0110] Determination of NCO content by FT-IR: IR spectra were recorded on a Spectrum of FT-IR spectrometer manufactured by Perkin Elmer, Inc. equipped with an ATR unit. The residual nitrogen content was determined by the change in isocyanate groups (at 2270 cm -1 The signal was monitored by recording the band at

[0111] Determination of Tg value of cured resin by DSC: The glass transition temperature (Tg) of the post-cured prepregs was determined by differential scanning calorimetry (DSC) on a TA DSC Q20 according to IPC-TM-650 2.4.25.

[0112] Determination of Tg value of CCL by DMA: The glass transition temperature, Tg, of the base laminate material without any cladding was determined using dynamic mechanical analysis according to IPC-TM-650 2.4.24.4.

[0113] Determination of Td value of CCL by DMA: The thermal decomposition temperature T of the base laminate material without cladding was determined using thermogravimetric analysis according to IPC-TM-650 2.4.24.6. dDetermine the temperature T at which the mass of the sample is 5.0% less than the mass measured at 50°C. d (5%).

[0114] Determining the Dk and Df values ​​of CCL by SPDR: The dielectric constant (Dk) and dissipation factor (Df) of the base laminate material without cladding were determined using a split post dielectric resonator (SPDR) at 10G microwave frequencies in accordance with IEC 61189-2-721.

[0115] raw materials: Desmodur N 3600 is a hexamethylene diisocyanate (HDI) trimer (NCO functionality >3) with an NCO content of 23.0% by weight and a viscosity of about 1200 mPas at 23° C. (DIN EN ISO 3219 / A.3) from Covestro AG.

[0116] Desmodur N 3900 is an HDI trimer (NCO functionality >3) with an NCO content of 23.5% by weight and a viscosity of about 730 mPas at 23° C. (DIN EN ISO 3219 / A.3) manufactured by Covestro AG.

[0117] Desmodur eco N 7300 is a biobased pentamethylene diisocyanate (PDI) trimer (NCO functionality >3) with an NCO content of 21.9% by weight and a viscosity of about 9500 mPas at 23° C. (DIN EN ISO 3219 / A.3) from Covestro AG.

[0118] Desmodur Z4470 is an isophorone diisocyanate (IPDI) trimer (NCO functionality >3) in butyl acetate (BA) or solvent naphtha (SN) with a solids content of 70% by weight, an NCO content of 11.9% by weight, a viscosity of about 1500 mPas at 23° C. (DIN EN ISO 3219 / A.3) and is manufactured by Covestro AG.

[0119] Desmodur IL is a toluene diisocyanate (TDI) trimer (NCO functionality >3) in butyl acetate (BA) or ethyl acetate (EA) with a solids content of 51 wt. %, an NCO content of 8.0 wt. % and a viscosity of 700-2000 mPas at 23° C. (DIN EN ISO 3219 / A.3) from Covestro AG.

[0120] Desmodur XP 2489 is an HDI isophorone diisocyanate (IPDI) polyisocyanate (NCO functionality >3) with an NCO content of 21.0% by weight and a viscosity of about 22,500 mPas at 23° C. (DIN EN ISO 3219 / A.3) from Covestro AG.

[0121] Catalyst: 2-[2-(dimethylamino)ethyl-methylamino]ethanol is purchased from TCI Co. Ltd.

[0122] Solvent: Butyl acetate is purchased from Sinopharm Chemical Reagent Co., Ltd. with a purity of ≧99.0%.

[0123] Silica powder is purchased from Denka Co., jp.

[0124] Type 2116E woven glass fiber fabric is purchased from CTM glass fiber Co., Ltd.

[0125] General method for producing resin composition and prepreg 1. Add the ingredients listed in Tables 1 and 2 to a mixing vessel; 2. Mix the ingredients at room temperature using a SpeedMixer DAC 400 FV for 60-300 seconds at 2500 rpm. At this point the composition is ready for use.

[0126] 3. The thoroughly mixed composition was impregnated into 2116 glass woven fabric and adjusted to have an appropriate thickness.

[0127] 3. The impregnated glass cloth was baked at 180-200°C for 2-15 minutes to remove the solvent and partially harden it to produce a prepreg.

[0128] The residual NCO content was monitored by FT-IR.

[0129] Storage stability was checked by monitoring the residual NCO content after several days using FT-IR.

[0130] 4. The prepreg is then pressed at 200-220°C, preferably under some pressure, for example 5 bar, to obtain a fibre composite component.

[0131] The residual NCO content after post-cure was monitored by FT-IR.

[0132] The Tg and Td of the cured resin in the composition were monitored by DSC and TGA.

[0133] Application examples: To prepare the CCL, the resin compositions from Example 1, Example 2 and Comparative Example 2 were mixed with 30 wt% silica powder in butyl acetate at a certain ratio, respectively, to adjust the solid content of the adhesive solution to 65%. 2116 glass cloth was impregnated with the above adhesive solution, adjusted to an appropriate thickness, and then baked in a furnace at 180-200 °C for 2-15 minutes to form a prepreg. Then, six prepregs were laminated by overlapping copper foil on both sides, and cured at a curing temperature of 170-250 °C and a curing pressure of 25-50 bar for 200-300 minutes to obtain a copper-clad laminate.

[0134] The Tg of CCL was monitored by DMA. The Td of CCL was monitored by TGA. The DK and Df of CCL were monitored by SPDR.

[0135] The performance of the CCL is shown in Table 3.

[0136] [Table 1]

[0137] [Table 2]

[0138] [Table 3]

[0139] Examples 1-7 show that the resin composition of the present invention provides a viable prepreg solution with good storage stability. Examples 1-6, in comparison with Example 7, show that polyisocyanates with isocyanurate structures (Examples 1-6) should be used rather than asymmetric trimers (Example 7) when high heat resistance is required as an additional property.

[0140] Comparative Example 1 (10% IPDI trimer + 90% HDI trimer) and Comparative Example 4 (20% IPDI trimer + 80% PDI trimer) show that a low content of IPDI trimer also results in a low Tg.

[0141] Comparative Example 2 showed that (i) the Tg of the system was too low to meet the CCL application requirements, and (ii) the system with only aliphatic polyisocyanate was already almost completely cured after the first curing step, and only a few NCO groups were further consumed during the second curing step, resulting in poor adhesion or interlayer strength for making composites. This problem was shown in Comparative Application Example 1.

[0142] Comparative Example 3 shows that the pure aromatic trimer makes the system moisture sensitive and quickly becomes a highly viscous system that cannot be easily used to impregnate fibers. During storage, the free isocyanate is easily consumed, so that there is not enough residual NCO content left for further pressing for the second curing step. Therefore, this system is not practical for industrial use.

Claims

1. 1. A polymerizable composition that is free of isocyanate-reactive groups or has an isocyanate component with a molar ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0:1.0, a) at least one aliphatic polyisocyanate; b) at least one cycloaliphatic polyisocyanate; and c) at least one trimerization catalyst; Including, wherein the concentration of the cycloaliphatic polyisocyanate is from 25% to 75% by weight based on the total weight of all polyisocyanates present in the polymerizable composition; and wherein the concentration of the uretdione-forming catalyst in the composition is 10% by weight or less of the total mass of the uretdione-forming catalyst and the trimerization catalyst present in the polymerizable composition.

2. 10. The polymerizable composition of claim 1 further comprising from 10% to 50% by weight, based on the total of all polyisocyanates, all trimerization catalysts, and all solvents, of at least one inert solvent.

3. 3. The polymerizable composition of claim 1, wherein the at least one aliphatic polyisocyanate comprises from 10% to 80% by weight of the total amount of all polyisocyanates present in the polymerizable composition.

4. 4. The polymerizable composition of claim 1, wherein the at least one aliphatic polyisocyanate and / or the at least one cycloaliphatic polyisocyanate is an oligomeric polyisocyanate containing at least 50 mol % of isocyanurate structures, based on the sum of oligomeric structures from the group consisting of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structures present in the respective polyisocyanate.

5. Formula (I) 【Chemistry 1】 [In the formula, R １ and R ２ are each independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5-alkyl, unbranched C5-alkyl, branched C6-alkyl, unbranched C6-alkyl, branched C7-alkyl and unbranched C7-alkyl; A is O, S and NR ３ wherein R ３ is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, and isobutyl; B is, independently of A, OH, SH, NHR ４ and N.H. ２ wherein R ４ is selected from the group consisting of methyl, ethyl and propyl. The polymerizable composition according to any one of claims 1 to 4, wherein a trimerization catalyst according to

6. The polymerizable composition according to any one of claims 1 to 5, further comprising an organic or inorganic filler.

7. below a) providing a polymerizable composition according to any one of claims 1 to 6; and b) curing the polymerizable composition at a temperature between 150° C. and 200° C., thereby obtaining a semi-finished product. The method includes:

8. 8. The method according to claim 7, wherein method step b) is continued until the polymerizable composition reaches a viscosity of from 30,000 to 750,000 mPas.

9. 9. The process according to claim 7 or 8, wherein the process steps are continued until from 2% to 60% of the free isocyanate groups present at the start of process step b) have been consumed.

10. The method according to any one of claims 7 to 9, further comprising a method step a1) of coating at least one organic or inorganic fiber with the polymerizable composition provided in method step a).

11. The method according to any one of claims 7 to 10, further comprising a method step c) of hardening said semi-finished product, whereby a final product is obtained.

12. The method according to claim 11, wherein method step c) is initiated 1 to 30 days after method step b) has ended.

13. A semi-finished product obtained or obtainable by the method according to any one of claims 7 to 10.

14. 13. A final product obtained or obtainable by the method according to claim 11 or 12.

15. A copper clad laminate or printed circuit board comprising a product obtained or obtainable by the method of claim 11 or 12.

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