Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/16—Catalysts
  • C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
  • C08G18/1825—Catalysts containing secondary or tertiary amines or salts thereof having hydroxy or primary amino groups
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/14—Layered products comprising a layer of metal next to a fibrous or filamentary layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/02—Layered products essentially comprising sheet glass, or glass, slag, or like fibres in the form of fibres or filaments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
  • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
  • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/02—Polymeric products of isocyanates or isothiocyanates of isocyanates or isothiocyanates only
  • C08G18/022—Polymeric products of isocyanates or isothiocyanates of isocyanates or isothiocyanates only the polymeric products containing isocyanurate groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/09—Processes comprising oligomerisation of isocyanates or isothiocyanates involving reaction of a part of the isocyanate or isothiocyanate groups with each other in the reaction mixture
  • C08G18/092—Processes comprising oligomerisation of isocyanates or isothiocyanates involving reaction of a part of the isocyanate or isothiocyanate groups with each other in the reaction mixture oligomerisation to isocyanurate groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/73—Polyisocyanates or polyisothiocyanates acyclic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/7875—Nitrogen containing heterocyclic rings having at least one nitrogen atom in the ring
  • C08G18/7887—Nitrogen containing heterocyclic rings having at least one nitrogen atom in the ring having two nitrogen atoms in the ring
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
  • C08G18/791—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups
  • C08G18/792—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
  • C08G18/791—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups
  • C08G18/794—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups formed by oligomerisation of aromatic isocyanates or isothiocyanates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
  • C08J5/241—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres
  • C08J5/244—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres using glass fibres
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/03—Use of materials for the substrate
  • H05K1/0313—Organic insulating material
  • H05K1/0353—Organic insulating material consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement
  • H05K1/0366—Organic insulating material consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement reinforced, e.g. by fibres, fabrics
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/05—5 or more layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
  • B32B2260/02—Composition of the impregnated, bonded or embedded layer
  • B32B2260/021—Fibrous or filamentary layer
  • B32B2260/023—Two or more layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
  • B32B2260/04—Impregnation, embedding, or binder material
  • B32B2260/046—Synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
  • B32B2262/10—Inorganic fibres
  • B32B2262/101—Glass fibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2457/00—Electrical equipment
  • B32B2457/08—PCBs, i.e. printed circuit boards
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2475/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/03—Use of materials for the substrate
  • H05K1/0313—Organic insulating material
  • H05K1/032—Organic insulating material consisting of one material
  • H05K1/0346—Organic insulating material consisting of one material containing N

Definitions

• the present invention relates to polyisocyanate compositions comprising two different types of polyisocyanate, their use in the manufacture of prepregs and polyisocyanurate composited made from said prepregs.
• Composite materials reinforced with fibers such as carbon fibers or glass fibers have been receiving attention because of their characteristics, i.e., good heat resistance and good mechanical strength despite their lightness. They have been more widely used in various structural applications such as printed circuit boards, chassis, and various members of auto-mobiles and aircrafts.
• a frequently used method for molding such a fiber-reinforced resin composite material employs an intermediate material called a prepreg.
• a prepreg reinforcing fibers are impregnated with a thermosetting resin. The impregnated fibers are then cured and molded by autoclave molding or press molding.
• resins for prepregs are required to have both storage stability even at room temperature and curability by heating or the like.
• An additional desired feature is possibility of cutting the prepregs to size, without the cutting tools becoming contaminated with the often sticky matrix material.
• thermosetting resins such as epoxy resin compositions have often been used.
• Prepregs containing epoxy resins disadvantageously need to be stored at low temperatures because curing already proceeds at normal temperature.
• Prepregs and composite components produced therefrom, based on epoxy systems are described e.g. in EP 0981427.
• Another barrier for the polyurethane prepreg application for PCBs is their low heat resistance, the glass transition temperature for a PU-based prepreg reported e.g. in WO 2012/038105 is only with Tg at ca. 70 Q C, and in WO 2013/139704, the Tg of the final cured resin is 146 Q C which are both too low to meet the requirement of PCB of normally more than 150 Q C.
• the object of the present invention is to provide prepregs which can be produced by means of a simple process and are storage-stable at room temperatures for a plurality of weeks.
• the prepregs are moreover intended to be almost tack-free, so that they can easily be further processed.
• a further object of the invention is to provide a resin composition that can achieve a printed circuit board having a low dielectric property and a high glass transition temperature.
• WO 2018/087395 discloses a combination of acrylates and polyisocyanates so that two different crosslinking mechanisms are available which can be activated by different mechanisms, ionizing radiation and heat.
• WO 2020/152107 discloses the use of polyisocyanates with small proportions of polyols or polyamines.
• 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.
• higher temperatures are used to form isocyanurate groups from the remaining isocyanate groups.
• the resulting material comprises relevant amounts of crosslinking groups other than the isocyanurate group. Depending on the application this may be undesirable as the isocyanurate group has particularly advantageous properties.
• the problem underlying the present invention is the provision of a dual curing mechanism which allows the manufacture of polyisocyanurate plastics in two different curing steps so that a storage- stable semi-finished product can be obtained in a first curing step and be fully cured in a second one.
• the present invention relates to a polymerizable composition which is free from isocyanate-reactive groups or has or a molar ratio of isocyanate groups of the isocyanate component 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; wherein the concentration of cycloaliphatic polyisocyanates is 25 wt.-% to 75 wt.-% based on the total mass of all polyisocyanates present in the polymerizable composition; and wherein , the concentration of uretdione-forming catalysts in the composition is not more than 10 wt.-% of the total mass of uretdione-forming catalysts and trimerization catalysts present in the polymerizable composition.
• a “polymerizable composition” is a composition which comprises the components defined above optionally further components set out below. In a “polymerizable composition” said components are mixed in such a way that the composition can be used to form a polymer by simple heating.
• the polymerizable composition of the present invention is particularly suitable for the manufacture of prepreg materials.
• Prepreg materials are materials comprising thermoset polymer which has been partially cured so that the material can be handled or transported. However, the curing during the manufacture of the prepreg must not proceed to a point, where the material becomes too hard and brittle to be worked with, e.g. by bending. In the polymerizable composition of the present invention this is achieved by the combination of at least two different polyisocyanates having a different reactivity.
• a first curing step at lower temperatures creates the prepreg mainly by crosslinking the isocyanate group of the more reactive polyisocyanate and a second curing step can then be used to obtain a hard and fully cured material which is fit for the intended use.
• aromatic polyisocyanates have the highest reactivity
• araliphatic polyisocyanate have the second highest reactivity
• aliphatic polyisocyanates have the second lowest reactivity
• cycloaliphatic polyisocyanates are the least reactive species.
• the aliphatic polyisocyanate has to be paired with at least one polyisocyanate having a different reactivity.
• Species which fulfill this requirements are cycloaliphatic, aromatic and araliphatic polyisocyanates. If the combination of the aliphatic polyisocyanate with a slower curing species is desired, it should be mixed with at least one cycloaliphatic polyisocyanate. If the combination of the aliphatic polyisocyanate with a faster curing species is desired, it should be mixed with at least one araliphatic and / or aromatic polyisocyanate.
• the polymerizable composition comprises at least one aliphatic polyisocyanate and at least one cycloaliphatic polyisocyanate.
• the at least one aliphatic polyisocyanate makes up 10 wt.-% to 80 wt.-%, preferably 25 wt.-% to 65 wt.-% of the total amount of all polyisocyanates present in the polymerizable composition.
• the preferred content of cycloaliphatic polyisocyanates is 25 wt.-% to 75 wt.-%, more preferably 30 wt.-% to 70 wt.-%.
• araliphatic and aromatic polyisocyanates make up not more than 10 wt.-%, more preferably not more than 5 wt.-% of the total amount of all polyisocyanates present in the polymerizable composition. Most preferably, the polymerizable composition is free from the aforementioned polyisocyanates.
• the polymer obtainable by polymerizing the polymerizable composition of the invention receives its advantageous properties very substantially through crosslinking of the isocyanate groups with one another. Consequently, it is essential to the invention that the ratio of isocyanate groups to the total amount of the isocyanate-reactive groups in the polymerizable composition is restricted such that there is a distinct molar excess of isocyanate groups.
• the molar ratio of isocyanate groups of the isocyanate component to isocyanate-reactive groups 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 and even more preferably at least 8.0 : 1.0.
• composition may also be free from isocyanate-reactive groups.
• isocyanate-reactive groups in the context of the present application are hydroxyl, thiol, carboxyl and amino groups, amides, urethanes, acid anhydrides and epoxides.
• the polymerizable composition additionally comprises at least on organic solvent which does not contain isocyanate-reactive groups, also referred to as "inert solvent".
• inert solvent an organic solvent which does not contain isocyanate-reactive groups
• concentration of this solvent is such that the viscosity of the polymerizable composition is between 100 mPas and 2,000 mPas.
• the polymerizable composition preferably comprises 10 wt.-% to 50 wt.-% inert solvent based on the sum of all polyisocyanates, all trimerization catalysts and all solvents.
• the polymerizable composition additionally comprises an organic or inorganic filler.
• a “polyisocyanate component” refers to the totality of all polyisocyanates belonging to this species.
• aliphatic polyisocyanate component refers to the sum of all aliphatic polyisocyanates present in the polymerizable composition
• aromatic polyisocyanate component refers to all aromatic polyisocyanates
• cycloaliphatic polyisocyanate component refers to the sum of all cycloaliphatic polyisocyanates.
• polyisocyanates Because of the polyfunctionality (> 2 isocyanate groups), it is possible to use polyisocyanates to produce a multitude of polymers (e.g. polyurethanes, polyureas and polyisocyanurates) and low molecular weight compounds (for example those having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and/or oxadiazinetrione structure).
• polyisocyanates in this application refers equally to monomeric and/or oligomeric polyisocyanates. For the understanding of many aspects of the invention, however, it is important to distinguish between monomeric diisocyanates and oligomeric polyisocyanates.
• oligomeric polyisocyanates this means polyisocyanates formed from at least two monomeric diisocyanate molecules, i.e. compounds that constitute or contain a reaction product formed from at least two monomeric diisocyanate molecules.
• oligomeric polyisocyanates from monomeric diisocyanates is also referred to here as modification of monomeric diisocyanates.
• modification means the reaction of monomeric diisocyanates to give oligomeric polyisocyanates having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and/or oxadiazinetrione structure.
• hexamethylene diisocyanate is a "monomeric diisocyanate” since it contains two isocyanate groups and is not a reaction product of at least two polyisocyanate molecules:
• Reaction products which are formed from at least two HDI molecules and still have at least two isocyanate groups are "oligomeric polyisocyanates" within the context of the invention.
• Representatives of such "oligomeric polyisocyanates" are, proceeding from monomeric HDI, for example, HDI isocyanurate and HDI biuret, each of which is formed from three monomeric HDI units:
• the proportion of isocyanate groups based on the total amount of the all polyisocyanates present in the polymerizable composition is at least 15% by weight.
• any polyisocyanate may consist essentially of monomeric polyisocyanates or essentially of oligomeric polyisocyanates. It may alternatively comprise oligomeric and monomeric polyisocyanates in any desired mixing ratios.
• the polyisocyanates used as reactants in the trimerization have a low level of monomers (i.e. a low level of monomeric diisocyanates) and already contain oligomeric polyisocyanates. If the monomer content of the polyisocyanate composition is too high, the first curing step does not result in a storage stable semi-finished product.
• the expressions "having a low level of monomers” and “having a low level of monomeric diisocyanates" are used here synonymously.
• a polyisocyanate has a proportion of monomeric diisocyanates of not more than 20 % by weight, especially not more than 15 % by weight or not more than 10 % by weight, based in each case on the weight of the respective polyisocyanate.
• a polyisocyanate has a content of monomeric diisocyanates of not more than 5 % by weight, preferably not more than 2.0 % by weight, more preferably not more than 1.0 % by weight, based in each case on the weight of the respective polyisocyanate.
• Particularly good results are established when the polyisocyanate is essentially free of monomeric diisocyanates. "Essentially free” here means that the content of monomeric diisocyanates is not more than 0.5 % by weight, based on the weight of the polyisocyanate.
• each isocyanate consists entirely or to an extent of at least 80 %, 85 %, 90 %, 95 %, 98 %, 99 % or 99.5 % by weight, based in each case on the weight of the respective polyisocyanate, of oligomeric polyisocyanates. Preference is given here to a content of oligomeric polyisocyanates of at least 99 % by weight. This content of oligomeric polyisocyanates relates to the polyisocyanate as provided. In other words, the oligomeric polyisocyanates are not formed as intermediate during any process of the invention, but are already present in the polymerizable composition on commencement of any reaction.
• Polyisocyanate compositions which have a low level of monomers or are essentially free of monomeric isocyanates can be obtained by conducting, after the actual modification reaction, in each case, at least one further process step for removal of the unconverted excess monomeric diisocyanates.
• This removal of monomers can be effected in a particularly practical manner by processes known per se, preferably by thin-film distillation under high vacuum or by extraction with suitable solvents that are inert toward isocyanate groups, for example aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane or cyclohexane.
• the polyisocyanate components of the invention are obtained by modifying monomeric diisocyanates with subsequent removal of unconverted monomers.
• the oligomeric polyisocyanates may, in accordance with the invention, especially have uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and/or oxadiazinetrione structure.
• the oligomeric polyisocyanates have at least one of the following oligomeric structure types or mixtures thereof:
• 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 mo-1%, even more preferably still at least 90 mol-% and especially preferably at least 95 mol-%, based on the sum total of the oligomeric structures from the group consisting of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure present in the aliphatic polyisocyanate component.
• a cycloaliphatic polyisocyanate component 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 still at least 90 mol-% and especially preferably at least 95 mol-%, based on the sum total of the oligomeric structures from the group consisting of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure present in the cycloaliphatic polyisocyanate component.
• the proportions of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and/or oxadiazinetrione structure in a polyisocyanate can be determined, for example, by NMR spectroscopy. It is possible here with preference to use 13C N MR spectroscopy, preferably in proton-decoupled form, since the oligomeric structures mentioned give characteristic signals.
• an oligomeric polyisocyanate for use in the present invention preferably has an (average) NCO functionality of 2.0 to 5.0, preferably of 2.3 to 4.5.
• all isocyanate groups are bonded to a carbon atom that is part of an open carbon chain. This may be unsaturated at one or more sites.
• the aliphatically bonded isocyanate groups are preferably bonded at the terminal carbon atoms of the carbon chain.
• Aliphatic polyisocyanates that are particularly suitable according to the invention are 1,4- diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-l,5- diisocyanatopentane, l,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-l,6- diisocyanatohexane and 1,10-diisocyanatodecane and oligomers derived therefrom.
• BDI 1,4- diisocyanatobutane
• PDI 1,5-diisocyanatopentane
• HDI 1,6-diisocyanatohexane
• 2-methyl-l,5- diisocyanatopentane l,5-diisocyanato-2,2-dimethylpentane
• a cycloaliphatic polyisocyanate all isocyanate groups are bonded to carbon atoms which are part of a closed ring of carbon atoms. This ring may be unsaturated at one or more sites provided that it does not attain aromatic character as a result of the presence of double bonds.
• Cycloaliphatic polyisocyanates that are particularly suitable according to the invention are 1,3- and 1,4- diisocyanatocyclohexane, l,4-diisocyanato-3,3,5-trimethylcyclohexane, l,3-diisocyanato-2- methylcyclohexane, l,3-diisocyanato-4-methylcyclohexane, l-isocyanato-3,3,5-trimethyl-5- isocyanatomethylcyclohexane (isophorone diisocyanate; IPDI), l-isocyanato-l-methyl-4(3)- isocyanatomethylcyclohexane, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 1,3- and
• Araliphatic polyiolyisocyanates that are particularly suitable according to the invention are 1,3- and
• Aromatic polyisocyanates are aromatic polyisocyanates
• Aromatic polyisocyanates that 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 oligomers derived therefrom.
• TDI 2,4- and 2,6- diisocyanatotoluene
• MDI 2,4'- and 4,4'-diisocyanatodiphenylmethane
• 1,5- diisocyanatonaphthalene and oligomers derived therefrom 1,5- diisocyanatonaphthalene and oligomers derived therefrom.
• a "trimerization catalyst” as understood in the present application is catalyst which catalyzes the addition of isocyanate groups to isocyanurate structures. It is preferred that said catalyst converts not more than 20 mol-%, more preferably not more than 10 mol-% and most preferably not more than 5 mol-% of the isocyanate groups in the polymerizable composition to uretdione groups as these groups are less stable and compromise the chemical and physical properties of the material. Moreover, the concentration of uretdione-forming catalysts in the composition is preferably not more than 10 wt.-%, more preferably not more than 3 wt.-% of the total mass of uretdione-forming catalysts and trimerization catalysts present in the polymerizable composition. Most preferably, the composition is free of uretdione-forming catalysts.
• Suitable trimerization catalysts are, for example, simple tertiary amines, for example triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine or N,N'-dimethylpiperazine.
• Suitable catalysts also include the tertiary hydroxyalkylamines described in GB 2 221465, for example triethanolamine, N-methyldiethanolamine, dimethylethanolamine, N-isopropyldiethanolamine and l-(2- hydroxyethyl)pyrrolidine or the catalyst systems known from GB 2 222 161 that consist of mixtures of tertiary bicyclic amines, for example DBU, with simple aliphatic alcohols of low molecular weight.
• 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, for example 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)-l,4-diazabicyclo[2.2.2]octane hydroxide (monoadduct of ethylene oxide and water onto l,4-diazabicyclo[2.2.2]octane), the quaternary hydroxyalkylammonium hydroxides known from EP-A 3765 or EP-A 10589, for example N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium hydroxide, the trialkylhydroxylalkylammonium carboxylates that are known from DE-A 2631733, EP-A 0671426, EP- A 1 599 526 and US 4,789,705, for example N,N,N-trimethyl-N-2-hydroxypropylammonium p-tert- butylbenzoate and N,N,N-trimethyl-N-2-hydroxypropylammonium 2-ethylhexanoate, the quaternary benzylammonium carboxylate
• Suitable salts are the known sodium and potassium salts of linear or branched alkanecarboxylic acids having up to 14 carbon atoms, for example butyric acid, valeric acid, caproic acid, 2-ethylhexanoic acid, heptanoic acid, caprylic acid, pelargonic acid and higher homologs.
• trimerization catalysts are a multitude of different metal compounds. Suitable examples are the octoates and naphthenates of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium or lead or mixtures thereof with acetates of lithium, sodium, potassium, calcium or barium that are described as catalysts in DE-A 3 240613, the sodium and potassium salts of linear or branched alkanecarboxylic acids having up to 10 carbon atoms that are disclosed by DE-A 3 219 608, such as of propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid and undecylic acid, the alkali metal or alkaline earth metal salts of aliphatic, cycloaliphatic or aromatic mono- and polycarboxylic acids having 2 to 20 carbon atoms that are disclosed by EP-A 0 100 129, such as sodium benzoate or potassium benzoate
• trimerization catalysts suitable for the process of the invention can be found, for example, in J. H. Saunders and K. C. Frisch, Polyurethanes Chemistry and Technology, p. 94 ff. (1962) and the literature cited therein.
• 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.
• alkali metal or alkaline earth metal salts of aliphatic, cycloaliphatic or aromatic mono- and polycarboxylic acids having 2 to 20 carbon atoms are particularly suitable.
• the potassium salt of any of the abovementioned carboxylic acids is yet more preferred. Potassium acetate is particularly preferred.
• trimerization catalyst catalysts of formula (I) and their adducts.
• R 1 and R 2 are independently of one another 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 selected from the group consisting of 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 of A selected from the group consisting of OH, SH NHR 4 and NH2, wherein R 4 is selected from the group consisting of methyl, ethyl and propyl.
• A is NR 3 , wherein R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl.
• R 3 is preferably methyl or ethyl.
• R 3 is particularly preferably methyl.
• B is OH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• B is SH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• B is N HR 4 and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• R4 is selected from the group consisting of methyl, ethyl and propyl. It is preferable when R4 is methyl or ethyl. R4 is particularly preferably methyl.
• B is NH2 and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• A is oxygen
• B is OH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• B is SH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• B is N HR 4 and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• R 4 is selected from the group consisting of methyl, ethyl and propyl.
• R4 is methyl or ethyl.
• R4 is particularly preferably methyl.
• B is NH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• A is sulfur
• B is OH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• B is SH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• B is N HR 4 and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• R 4 is selected from the group consisting of methyl, ethyl and propyl. It is preferable when R4 is methyl or ethyl. R4 is particularly preferably methyl.
• B is NH and R 1 and R 2 are independently of one another 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. It is preferable when R 1 and R 2 are independently of one another methyl or ethyl. R 1 and R 2 are particularly preferably methyl.
• adducts of a compound of formula (I) and a compound having at least one isocyanate group are also suitable.
• adduct is understood to mean urethane, thiourethane and urea adducts of a compound of formula (I) with a compound having at least one isocyanate group.
• a urethane adduct is particularly preferred.
• the adducts of the invention are formed when an isocyanate reacts with the functional group B of the compound defined in formula (I). When B is a hydroxyl group a urethane adduct is formed. When B is a thiol group a thiourethane adduct is formed. And when B is NH2 or NHR 4 a urea adduct is formed.
• Suitable catalyst solvents are, for example, solvents that are inert toward isocyanate groups, 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, l-methoxy-2-propyl acetate, 3-methoxy-n-butyl acetate, propylene glycol diacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, lactones, such as b-propiolactone, y- butyrolactone, e-caprolactone and e-methylcaprolactone, but also solvents such as N
• catalyst solvents which bear groups reactive toward isocyanates and can be incorporated into the polyisocyanurate resin.
• solvents are mono- or polyhydric simple alcohols, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, n-hexanol, 2-ethyl-l-hexanol, ethylene glycol, propylene glycol, the isomeric butanediols, 2-ethylhexane-l,3-diol or glycerol; ether alcohols, for example l-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,
• Suitable solvents must be inert toward 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, l-methoxyprop-2-yl acetate, 3-methoxy-n-butyl acetate, propylene glycol diacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, lactones such as b-propiolactone, y- butyrolact
• inorganic or inorganic filler Any type of inorganic or inorganic filler known in the art may be used.
• Preferred inorganic fillers are selected from the group consisting of metal oxides, nitrites, silicides, particularly silica, borides, particularly 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 (triallyly 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.
• the polymerizable composition of the present invention may comprise at least one additive selected from the group consisting of antioxidants, flame retardants, heat stabilizers, antistatic agents, UV-absorbers, pigments, wetting agents, defoaming agents, colorants, lubricants, adhesion promoters, additional monomers and compatibilizers.
• additional monomers are selected from the group consisting of styrene, vinyl toluene, t-butyl styrene, para-methyl styrene, diallyl phthalate, 2, 4- ethylmethyl imidazole, 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.
• the present invention relates to a method comprising the steps of a) providing a polymerizable composition as defined above in this application; and b) curing the polymerizable composition at a temperature between 150 °C and 200 °C, whereby a semi-finished product is obtained.
• a polymerizable composition refers to a process which results in a polymerizable composition as set forth above. Suitable methods are known in the art.
• the curing in method step results in a "semi-finished product", i.e. in a material which can be processed further or transported but is still soft and flexible enough to be processed, e.g. by pressing it into a mold.
• step b) is continued until the resulting polymer is tack-free.
• method step b) is continued until 2 % to 60% of the free isocyanate groups present at the beginning of method step b) are consumed.
• 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 and most preferably 100,000 to 750,000 mPas.
• the viscosity is preferably determined using a cone and plate viscosimeter at a temperature of 23 °C and a shear rate of 1/s.
• step b) is continued until module G ' determined by a plate-plate rheometer according to ISO 6721-10:2015-09 at a temperature of 23 °C and a shear rate of 1/s reaches 5 x 10 3 Pa.
• method step b) is preferably continued until at least 90 wt.-% of the organic solvent are evaporated.
• This criterium is preferably combined with one or more of the above-defined criteria which relate to the state of polymer network.
• step b) at least 20 %, preferably at least 30 % of the free isocyanate groups present at the beginning of method step b) are still present so that a second curing step is possible.
• Method step b) is preferably performed at a temperature between 150 °C and 200 °C for 1 to 20 minutes.
• the combination of temperature and duration for the first curing step depend on the geometry of the product and the types of polyisocyanate and catalyst(s) present in the polymerizable composition to be used. It can easily be determined by simple preliminary experiments applying one of the preferred end points of method step b) set forth above.
• Method step b) can easily be stopped by decreasing the temperature to a temperature of not more than 60 °C, preferably not more than 40 °C.
• the polymerizable composition a fiber or a metal sheet is coated with the polymerizable composition provided in method step a) before commencing method step b).
• the fiber may be any inorganic or organic fiber used in the art for making composite materials.
• the fiber may have a size.
• the metal sheet is preferably a copper sheet.
• Preferred inorganic fibers are glass fibers, basalt fibers, boron fibers, ceramic fibers, whiskers, silica fibers and metallic reinforcing 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.
• the semi-finished product resulting from method step b) is a so- called "prepreg".
• prepreg refers to a fiber or a plurality of fibers or a metal sheet pre-coated with a polymerizable composition which has been partially cured so that said fiber or fibers or metal sheet can be transported or processed.
• the method of the present invention results in particularly advantageous semi-finished products because crosslinking of isocyanate groups by trimerization only proceeds at temperatures far above room temperature so that the semi-finished can be stored for several weeks at room temperature without losing its ability to be processed further.
• the present invention relates to a semi-finished product obtained or obtainable by the method of the present invention.
• Method steps a) and b) result in a semi-finished product which may be sold, transported and processed further by the customer.
• said semi-finished product is a prepreg.
• the method of the present invention comprises an additional method step c) of curing the semi-finished product, whereby a finished product is obtained.
• Method step c) preferably proceeds until at least 90 % of the isocyanate groups originally present in the polymerizable composition at the beginning of method step b) are consumed.
• a temperature between 200 °C and 250 °C is preferred.
• the preferred duration of method step c) is 1 hour to 8 hours, more preferably 2 hours to 6 hours. It is preferred that method step c) is commenced 1 day to 30 days, more preferably 3 days to 14 days, after method step b) is finished.
• the location at which method step c) is performed is at least 1 km, more preferably at least 10 km away from the location at which method step b) is performed, i.e. that the semi-finished product is transported to a different location before the second curing step.
• Method step c) results in a fully cured product.
• the present invention relates to a finished product obtained or obtainable by the method of the present invention comprising method steps a), b) and c) as defined above.
• the finished product forms part of a laminate, metal-clad laminate or printed circuit board, more preferably of a copper-clad laminate or printed circuit board.
• the finished product is a polyisocyanurate plastic, i.e. it is a polymer whose crosslinking groups are predominantly isocyanurate groups. Compared with other polymers this product is characterized by superior hardness and heat resistance. Moreover, even without the addition of dedicated flame retardants it is intrinsically flame-proof.
• IR spectra were recorded on a Spectrum of FT-IR spectrometer from Perkin Elmer, Inc. equipped with an ATR unit. Residual NCO content was monitored by recording the change of isocyanate groups (band at 2270 cm 4 ).
• the glass transition temperature (Tg) of the prepregs after post curing was determined by differential scanning calorimetry (DSC) on a TA DSC Q20 according to IPC-TM-6502.4.25.
• the glass transition temperature Tg of the base laminate material without the cladding was determined using dynamic mechanical analysis according to IPC-TM-6502.4.24.4.
• the thermal decomposition temperature T d of base laminate material without the cladding was determined using thermogravimetric analysis according to IPC-TM-650 2.4.24.6 to record the temperature T d (5%) at which the mass of the sample is 5.0 % less than its mass measured at 50 Q C.
• the dielectric constant (Dk) and dissipation factor (Df) of base laminate material without the cladding was determined using split post dielectric resonator (SPDR) at 10G microwave frequency according to IEC 61189-2-721.
• Desmodur N 3600 is a hexamethylene diisocyanate (HDI) trimer (NCO functionality >3) with 23.0 wt.-% NCO content, the viscosity is about 1200 mPas at 23 °C (DIN EN ISO 3219/A.3), from Covestro AG.
• Desmodur N 3900 is a HDI trimer (NCO functionality >3) with 23.5 wt.-% NCO content, the viscosity is about 730 mPas at 23 °C (DIN EN ISO 3219/A.3), from Covestro AG.
• Desmodur eco N 7300 is a biobased pentamethylene diisocyanate (PDI) trimer (NCO functionality >3) with 21.9 wt.-% NCO content, the viscosity is about 9500 mPas at 23 °C (DIN EN ISO 3219/A.3), from Covestro AG.
• PDI pentamethylene diisocyanate
• Desmodur Z4470 is an isophorone diisocyanate (IPDI) trimer (NCO functionality >3) in butyl acetate (BA) or solvent naphtha (SN) with 70 wt.-% solid content, 11.9 wt.-% NCO content, the viscosity is about 1500 mPas at 23 °C (DIN EN ISO 3219/A.3), from Covestro AG.
• IPDI isophorone diisocyanate
• BA butyl acetate
• SN solvent naphtha
• Desmodur IL is a toluene diisocyanate (TDI) trimer (NCO functionality >3) in butyl acetate (BA) or ethyl acetate (EA) with 51 wt.-% solid content, 8.0 wt.-% NCO content, the viscosity is 700-2000 mPas at 23 °C (DIN EN ISO 3219/A.3), from Covestro AG.
• TDI toluene diisocyanate
• BA butyl acetate
• EA ethyl acetate
• Desmodur XP 2489 is a HDI isophorone diisocyanate (IPDI) polyisocyanate (NCO functionality >3) with 21.0wt.-% NCO content, the viscosity is about 22,500 mPas at 23 °C (DIN EN ISO 3219/A.3), from Covestro AG
• Catalyst 2-[2-(dimethylamino)ethyl-methylamino] ethanol is purchase from TCI Co. Ltd.
• Butyl acetate is purchased with the purity >99.0 % from Sinopharm Chemical Reagent Co., Ltd.
• Silica powder is purchased from Denka Co., jp.
• Type 2116 E-glass fiber woven cloth is purchased from CTM glass fiber Co., Ltd.
• the ingredients are mixed at 2500rpm for at 60-300 seconds using SpeedMixer DAC 400 FV at room temperature. At this point, the composition is ready for use.
• a 2116 woven glass cloth was impregnated into the well-mixed compositions and controlled to have an appropriate thickness
• the impregnated glass cloth was baked in an oven at 180-200 °C for 2-15 minutes for removing the solvent and partly curing the resin composition to prepare a prepreg.
• the residual NCO content was monitored by FT-IR.
• the storage-stability was checked by monitoring the residual NCO content after several days using FT-IR. 4.
• the prepreg was then pressed at
• the Tg and Td of the cured resin in composited was monitored by DSC and TGA.
• Example 1 For making CCL, the resin composition from Example 1, Example 2 and Comparative Example 2 are respectively mixed with 30 wt.-% of silica powder in a certain proportion in butyl acetate, and the solid content of the glue solution was controlled to be 65 %.
• a 2116 glass cloth was impregnated into the above-mentioned glue solution and controlled to have an appropriate thickness, and then based in an oven at 180-200 °C for 2-15min to prepreg a prepreg. Then 6 sheets of prepreg were stacked together with both sides stacked with copper foils and were cured at a curing temperature of 170-250 °C, and a curing pressure of 25-50 bar for 200-300 min to obtain a copper clad laminate.
• the Tg of CCL was monitored by DMA
• the Td of CCL was monitored by TGA
• Examples 1 to 7 show that the present resin compositions provide a feasible prepreg solutions with good storage stability. If high heat resistance is demanded as an additional property, examples 1 to 6 as compared to example 7 show that polyisocyanates having isocyanurate structures (examples 1 to 6) should rather be used than asymmetric trimers (example 7).
• 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 leads to low Tg.
• Comparative Example 2 shows (i) that the Tg for the system is too low to meet CCL application requirement and (ii) that a system with only aliphatic polyisocyanates is almost fully cured already after the first curing step. , during the second curing step, only slight NCO groups were further consumed, which will result in bad adhesion or interlay strength for making composites, This problem was shown as in Comparative application example 1.
• Comparative Example 3 shows that pure aromatic trimer will make the system moisture sensitive and will quickly become a high viscosity system which can't be easily used to impregnate the fiber. During the storage, the free isocyanate will be easily consumed, so that not enough residual NCO-content is left for the second curing step further pressing. Thus, this system is not practical for industrial application.

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• 2022
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