DE2413443A1 - Thermosetting poly(hexa substd melamines) prepn - by Lewis acid catalysed polymn of arylene bis (N-substd) cyanamides - Google Patents

Abstract

The poly(hexasubstd. melamines) consist essentially of segments of formula I (where R1 and R2 are (cyclo) lower alkyl or (alk)aryl, each opt. substd. by 1-2 Cl or 1-3 F or a lower (ar)alkoxy or lower perfluoroalkyl gp; each R3 is selected from divalent arylene gps. of formula (II) (where p is 0 or 1; n = 0 or 1; when n = 1, X is -O-, -S-, -CO-,-SO2-, C(R4)(R5) m or C(R4)(R5) m Y - C(R4)(R5) m; m = 1-20; Y is -O-, -S-, -CO-, -SO2-, -O-CO-, -N(R4)-CO-, or -CO-N(R4)-CO-; R4 and R5 are H, lower alkyl or phenyl), and are useful for laminates and composites used in high temp. or corrosive environments, and have good dielectric props. and high temp. stability.

Description

B e s c h r e i b u pertaining to the patent application: "Thermosetting Poly (hexasubstituted melamines) and Ver-Ull for their creation 'The invention relates si.ch-on new types of polymers that are stable at high temperatures, and in particular on heat stable polymers made from arylene-bis (N-substituted) cyanamides. The polymers according to the invention contain melamine (triamino-s-triazine) segments, in which each of the amine hydrogen atoms is replaced by an organic group; these segments are linked by arylene groups.

Polymers containing melamine segments have been used earlier manufactured. For example, US Pat. No. 2,824,088 describes polymers containing triarylamino-S-triazine radicals are contained and produced by reacting urihalogen triazines with diamines, the reaction proceeding with the release of hydrogen halide. With these Polymer is on each of the amino groups present in the triazine segments Hydrogen atom and then they have limited thermal stability.

Polymers with melamine segments, with which on each in the respective Triazine segment present amino group replaced all hydrogen atoms by an organic group are described in U.S. Patents 3,382,221 and 3,277,065.

However, these polymers are made by a free alkyl group catalyzed polymerization of hexasubstituted nelamines in which at least-four of the substituents are allyl groups and the polymerization proceeds via an addition reaction at the allyl double bond. In addition, these polymers must, according to the prior publications be prepared in an inert atmosphere because of the presence of oxygen interferes with the polymerization in more than trace amounts.

Polymers containing llelamine segments have also been made by polymerization in organic biscyanamides. For example, in the US-PS 3,291,673 and GS-Pn 1 009 892 described that alkylenedicyansmide thereby can be polymerized that they can be with or without a basic accelerator in the liquid state at the appropriate temperature. The polymers obtained contain, although they polymerize olive removal of volatile by-products are hydrogen atoms bonded to the nitrogen atoms. Also is in US Pat. No. 3,303,101 the preparation of copolymers by heating a Mixture of monocyanamides and dicyanamides described. According to the publication von Smolin and Rapoport, "The Chemistry of Heterocyclic Compounds", Interscience, New York, 1959, p. 357 contain the polymers described in these patents in all likelihood isomelamine segments.

Further above-described polymers with a content of melamine or. probably isomelamine segments are described in DP-PS 1 958 320 and 1 965 907 and NL-PS 67 / 05,451; these known polymeric products are obtained by reacting organic poly (N-substituted) gyanamides and sydroxy or thiol compounds or mixtures thereof.

It can be assumed, however, that these polymers are considerably less warm are more stable than the polymers according to the invention.

There were also attempts to use phenols as catalysts in the manufacture to use the inventive cyanamide monomers, unsuccessful in all balls.

The invention relates to novel thermosetting poly (hexasubstituted Melamines), which can be easily produced with the help of a Lewis acid catalyzed Polymeri sati on the appropriately substituted bis- (N-substituted-en) -cyanamides; this process does not require condensation with removal of volatile substances By-products still have an inert atmosphere and works through without using electronegative groups activated compounds and without the application of free radicals generating catalysts; also copolymerization with compounds that are active Containing hydrogen or active hydroxyl or diol groups does not take place. In addition, the poly (hexasubstituted melamines) according to the invention have one very high thermal stability and are hardly flammable and their dielectric Properties are particularly good.

The invention also relates to a method for production of the mentioned poly (hexasubstituted melamines), which do not remove condensation of unwanted volatile by-products, but in one by one Lewis acid catalyzed polymerization of divalent bis (N-substituted) cyanamides consists.

In the method according to the invention for the production of poly (hexasubstituted Melamines) both the use of activated by electronegative groups Compounds such as those from free radical generating catalysts are avoided as well copolymerization with compounds containing active hydrogen atoms or active hydroxyl or contain diol groups.

In the present description and claims, the terms mean "lower alkyl groups" and "lower alkoxy groups" are both straight chain and branched alkyl or. Alkoxy radicals with 1 to 6 carbon atoms. As "lower Alkyl groups "are for example straightforward: Hethyl, ethyl, n-propyl, isopropyl, , n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, n-hexyl, 2-ethylbutyl, 2,3-Dimethylbutyl and the like and as "lower alkoxy radicals" methoxy, ethoxy, n-propoxy, Isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, sec-pentoxy, n-hexyloxy, 2-ethylbutoxy, 2,3-dimethylbutoxy and the like; the term "cyclo-lower alkyl group" includes cycloalkyl radicals that are unsubstituted or substituted by lower alkyl groups with a total of 3 to 9 carbon atoms including, if substituted, the Carbon atoms in the lower alkyl substituent (s); Examples are: Cyclopropyl, cyclobutyl, methylcyclopropyl, cyclopentyl, ethylcyclopropyl, dimethylcyclopropyl, 2-methylcyclobutyl, 3-ethylcyclopropyl, 2,3-dimethylcyclobutyl, 2-ethylcyclobutyl, 3-ethylcyclobutyl, cycloheptyl, 2,3-diethylcyclopropyl, 2-methyl-3-ethylcyclopropyl, 2,3,4-trimethylcyclobutyl, 2-ethyl-3-methylcyclohexyl, cycloheptyl, cyclononyl, and the like; the term "aryl group" includes both substituted and unsubstituted monovalent organic radicals that arise from aromatic hydrocarbons by splitting off a Hydrogen atoms are formed; Examples are: phenyl, naphthyl, anthryl, pyridyl, Carbazyi, indolyl, 2-triazinyl, furyl, benzoxazolyl, benzthiazolyl and the like, wherein these Radicals optionally one or more lower alkyl or alkoxy, aryl, Can carry halogen, carbo-lower alkoxy, arylsulfonyl or nitro substituents.

The term "aryloxy group" embraces substituted or unsubstituted Aryloxy radicals, e.g. phenoxy, 2-naphthyloxy, 2-naphthoxy, 1-anthryloxy, 2-anthryloxy, 9-Anthryloxy and the like. Which optionally contain one or more lower alkyl or Alkoxy, aryl, halogen, carbo-lower alkoxy, arylsulfonyl or nitro substituents and the term "halogen" includes chlorine and fluorine.

The poly (hexasubstituted melamines) claimed here essentially consist of segments (repeating units) of the following structural formula: wherein R¹ and R², which may be the same or different, can stand for branched or straight-chain lower alkyl groups or for cyclo-lower-alkyl, aryl or alkaryl radicals which are optionally substituted by one or two chlorine atoms or 1 to 3 fluorine atoms or lower perfluoroalkyl, lower alkoxy, or aralkoxy groups; and in which R³, R³ 'and R³ ", which could also be the same or different, are divalent arylene radicals of the formula: are, wherein p is zero or 1 and n is zero or 1, where when n is 1, X is stands; and wherein m is an integer from 1 to 20, while Y is stands; and in which R4 and R5, which may be the same or different, represent hydrogen or a lower alkyl group or the phenyl group.

In the "B" state, the substances are more oligonuclear and thermoplastic.

They apparently contain a mixture of trimeric and hexameric chains of the starting dicyanamides, which in each individual polymer chain do not exceed about contain two triazine rings. Their mean molecular weight in the B stage is about 300 to 3000. In this state they are sufficiently soluble in chlorinated ones Hydrocarbons such as methylene chloride, chloroform and the like.

When carrying out the process according to the invention, the poly (hexasubstituted Melamine) in the B-state, resp.

the fully cured product, prepared by, in the presence of a Lewis acid, an arylene-bis- (N-substituted) -cyanamide of the formula: heated (R1, R² and R³ have the above meanings); one can also start from a mixture of such bis-cyanamides in which R) is one or more different divalent radicals, for example R³ 'or R3.

Among the arylene-bis (N-substituted) cyanamides that are used for production the poly (hexasubstituted melamines) according to the invention can be used, are examples of those in which "arylene" is a divalent radical, the following are mentioned: 1,4-phenylene-bis- (N-methylcyanamide); 1,4-phenylene-bis- (N-ethylcyanamide); 1,2-phenylene-bis (N-methylcyanamide); 1,4-phenylene-bis (N-phenylcyanamide); 1,4-phenylene-bis (N-phenylcyanamide); 1,4-phenylene-bis- [N- (4-methoxyphenyl) cyanamide]; 1,4-phenylene-bis [N- (4-phenoxyphenyl) cyanamide]; 4,4'-diphenylbis (N-phenylcyanamide); 4,4'-diphenyl-bis (N-methylcyanamide); 1,4-naphthalene-bis (N-methylcyanamide); bis- [4- (N-methylcyanamino) phenyl] sulfide; bis [4- (N-phenylcyanamino) phenyl] ketone; bis- [4- (N-phenylcyanamino) -phenyl] sulfone and bis- [4- [N-phenylcyanamino) -benzyl] -ketone.

The preferred bis- (N-substituted) -cyanamides are the arylene-bis- (N-acrylcyanamides), wherein R1 and R2 are lower alkyl groups and X in the above formula for -0- or -CH2-, e.g. bis- [4- (N-methylcyanamino) -phenyl] -methane and bis- [4- (N-methylcyanamino) -phenyl] -ether.

The arylene bis substituted) -Cyanamid.e as starting material prepared in a manner known per se, as described in the literature; see, for example, the preparation of arylene-bis (N-alkylcyanamides) by the by Braunsche Reaction of cyanogen bromide with arylene-bis- (N, N-dialkylamines) (Organic Reactions, Volume 7, pp. 198-262, Ed. John Wiley and Sons, New York 1953); the dehydration of bis-ureas described by Robinson, Can.

J. Chem. 32,901 (1954); the dehydration of thioureas, described by Kurzer, J. Chem. Soc., 1950, 3269 and the preparation of 1,4-dicyanopiperazine, described by Kramer, Chem. Zentral. 1910 I, 1532 and by Franchimont and Kramer, Rec. Trav. formerly 31, 64 (1912).

The poly (hex substituted melamines) claimed here are made by heating one or more arylene-bis (N-substituted) cyanamides with a Lewis acid catalyst. The temperature and heating time will be included the amount and type of Lewis acid catalyst adapted to carry out the Polymerization was chosen. Generally speaking, the temperature is between about 150 and 350 ° C and the polymerization time between about one and 48 hours and about 0.5 to 15% by weight of Lewis acid catalyst is used. The higher the temperature and the larger the amount of the catalyst, the shorter the time required is, so that the polymer is finally cured, has reached the B-stage.

The preferred conditions for the preparation of the invention Poly (hexasubstituted melamines) consist in that one the arylene-bis- (N-substituted) -cyanamides about 2 to 24 hours in the presence of 1 to 5% by weight of a Lewis acid as a catalyst holds at 200 to 25,000.

The polymerization reaction can be easily controlled.

Polymerization will proceed for any given amount of catalyst with appropriate heat application either up to the B-stage, where the formed Polymers are still soluble and thermoplastic or they will be continued until = to the final hardened state in which the polymers are crosslinked and therefore are insoluble. I) The polymerization can be stopped by turning off the heating interrupts when approximately the B-state is reached, whereby it is indifferent, whether a high or low proportion of catalyst is used for the polymerization became. The polymer can be used in this state at lower temperatures can be stored indefinitely, after which it can then simply be put through Can transfer heat application in the fully cured state.

The Lewis acids, which act as catalysts for the polymerization of arylene-bis- (N-substituted) -cyanamides are defined as substances with an electron gap and tend to be used to form a coordinated bond by accepting an electron pair. Suitable Lewis acids are chosen from the "hard" and "medium" Lewis acids, as classified in Pearson, J.Am.Chem.

Soc. 85,353 (1963); it is e.g. aluminum chloride, aluminum bromide or iodide, stannous chloride, antimony trichloride, indium trichloride, cobalt chloride, Cobalt bromide, indium oxide, cobalt oxide, ferric oxide, ferric chloride, manganate acetate, mangania acetylacetonate, Manganoacetylacetonate, titanium tetrachloride, titanium dioxide, boron trifluoride, boron trifluoride etherate, Boron trichloride, ferrous chloride, cobalt chloride, nickel chloride, manganese dioxide, zinc chloride, Zinc oxide, lead chloride, lead iodide and the like.

Some of these substances are of little aliveness and are used in the essential as a filler; be: i their use may require more active catalyst admit in order to fully cure within a reasonable time reach.

Preferred catalysts among the Lewis acids are those which show a low volatility, e.g.

Lewis acids, which do not volatilize below about 200 ° C still decompose; indium trichloride or zinc chloride are preferred. Polymerization the divalent arylene-bis (N-substituted) cyanamides can be carried out according to the invention are in the presence of a volatile Lewis acid as a catalyst, but you have to then use e.g. a pressure-resistant device for the polymerization to prevent that the catalyst escapes. The preferred catalysts are indium trichloride, Stannous chloride, antimony trichloride, cobalt chloride, zinc chloride, ferric chloride and the like corresponding bromides.

When carrying out the polymerization of the arylene-bis- (N-sub-substituted) -cyanamides obtained at lower polymerization temperature and shorter polymerization time hexasubstituted polymelamines in the B-state, i.e. which are thermoplastic. They can be kept for long periods of time to be hardened, however, osnc Cure anc0 fully at any time by heating.

The poly (hexasubstituted melamines) according to the invention are as a result especially their resistance to solvents and their high thermal stability suitable for use in a corrosive atmosphere and in an environment higher than this Exposed to temperatures. The fact that during No volatile substances are given off during the polymerization. The absence of -KB groups in these polymers seem to be the reason for their excellent Weather resistance and stability to the effects of corrosion as well as for their particularly good dielectric properties.

The polymers of the invention can be modified with a whole range of fibrous or finely divided inert fillers, such as clay, quartz flour, Asbestos, fiberglass and woven or non-woven fabrics, particles or fibers made of ceramic or metal and carbon powder or carbon fiber.

Laminates and similar structures, for example, can easily be manufactured indening the filler material with a mixture of arylene-bis (N-substituted) cyanamides or a mixture of the latter and an effective amount of the selected Lewis acid catalyst impregnated and the whole thing simply polymerized in the heat. Do you want storable In order to later process (e.g. deformable) laminates or composite products produce, the heating can only be carried out until the foluer in the B-stage is formed At a later point in time, such "green" laminates can then be converted into the desired Shaped and hardened in this state.

Laminates and composite masses with fillers can also be used under Use of poly- (hexasubstituted melamines) are produced in the B-stage, generated from one or more arylene-bis (N-substituted) cyanamides was. In this case, the B-staged polymer becomes a corresponding one Solvent dissolved, the filler soaked in the solution, the solvent removed and the impregnated filler deformed and finally cured; one can also melt the B-stage polymer, soak the filler with the melt and then deform and harden the whole thing.

The examples serve to explain the invention in more detail, wherein "Parts" means parts by weight.

B e i s p i e l 1 A mixture of 100 parts of bis- [4- (N-methylcyanamino) phenyl] methane and 2 parts of indium trichloride is heated to 200 ° C for 4 to 8 hours, so that forms a poly (hexane-substituted melamine) in the B-state. Receives after cooling a brittle, transparent mass that is thermoplastic and pulverized in the cold can be. It is soluble in methylene chloride or other chlorinated hydrocarbons. Apply a solution of the polymer to a metal, glass or ceramic surface and keeps the dried coating at 200 ° C for 14 hours and at 260 ° C for 2 hours, so tough, firmly adhering coatings are obtained. The curing of the polymer in the B-stage was caused by exposing the coating to 200 ul for 14 hours and 2 hours 26000 held. The cured polymer suffered a weight loss of only 5%, when heated isothermally to 26,000 for 1200 hours. It is common in all insoluble in organic solvents and shows in differential thermal analysis no glass transition temperature. The dynamic modulus of elasticity was measured on a sample of the cured polymer with the aid of a device of the "Complex Module Type 3930" certainly.

The sample had the following properties: Sample modulus (kg / cm) initially 0.29 x 105 after 170 h at 260 ° C 0.27 x 10 after 500 h at 260 ° C 0.30 x 105 The values show that the cured poly (hexane-substituted melamine) according to Example 1 remains stable on aging for at least 500 hours at 260 ° C, since this treatment the bend modulus of a sample remains essentially unchanged.

B e i n D i e l 2 20 parts of melamine polymer iL1 B-state according to the example 1 are dissolved in about 40 parts of chloroform, whereupon a tissue is made with the solution Glass wool is soaked to saturation. The soaked fabric is first applied dried in air and then in a vacuum (15 mm Hg) for a further 1 1/2 hours at 60.degree. It is then cut into strips and combined into a 5-ply laminate, in a press with 35 atm and pressed one hour to 2300, another hour 260 ° and heated to 290 ° C for another hour. The laminate thus obtained contains 75% glass wool and 25% hardened poly (hexasubstituted melamine). He is very strong, tough and resistant to moisture and solvents. The modulus of elasticity of the laminate is 2.74 x 106 kg / cm².

B e i s p i e l 3 The procedure described in Example 2 is used, the starting material being bis- [4- (N-methylcyanamino) phenyl] ketone is used.

A melamine polymer corresponding to the polymer according to Example 1 is obtained therefrom in the B-stage, from which coatings, impregnations and adhesives can be produced, which can be cured to a hard, glassy polymer.

B e i s p i e l 4 The procedure described in Example 1 is used, the starting material being bis- [4- (N-methylcyanamino) phenyl] ether is used. When polymerizing according to Example 1 gives the corresponding melamine polymer in the B-stage, the same as above hardness b can be.

EXAMPLE 5 When working according to Example 1, one uses as Starting material bis- [4- (N-Äthylcyanamino) -phenyl] ether. That with the polymer according to example 1 obtained melamine polymer in the B-stage has an average molecular weight of about 390 and can be cured to a very strong polymer as above.

EXAMPLE 6 Example 1 is repeated, but using 0.5 to 6 parts of indium chloride. A polymer is obtained whose properties match those according to example 2.

Mixtures containing 6 parts of indium chloride are perfect cured when held at 200 ° C for 2 hours and at 260 ° C for 2 hours. Mixtures containing 0.5 parts of indium chloride, on the other hand, require Z hours at 2000G and a further 2 hours at 260 0C for complete curing.

EXAMPLE In six different reaction vessels, 2 Parts up to- [4- (N-Methylcyanamino) -phenyl] methane introduced and carefully with the amount of Lewis acid catalyst specified below under a) to f) mixed. The hardening time required in each case in hours can be found in the list remove, after which a hard, infusible polymer was obtained.

Catalyst amount hardening time (hours) (parts by weight) a) ferric oxide 2.0 2 1/2 b) zinc oxide 0.005 18 c) cobalt oxide 0.05, 18 d) ferric chloride 0.05 18 e) manganoacetylacetonate 0.1 18 f) Mangania acetylacetonate 0.1 18 Other Lewis acids catalyzed in a similar manner including titanium dioxide, manganese oxide, nickel oxide, tin oxide, stannous fluoride, antimony trichloride, Nickel chloride and zinc chloride promote the polymerization of bis- (N-substituted) cyanamides at temperatures from 200 to 2700C.

Example 9 A series of filled poly (hexasubstituted Melamines) by adding 2 parts of bis-4- (N-methylcyanamino) -phenylmethane, 0.05 part of indium chloride and filler added in the amount given below. After carefully mixing the contents, place the jars in an oven at 270 ° C heated. The hardening time is shown in the list.

Filler Amount of hardening time (parts by weight) (hours) a) Ferric oxide 2.0 0.5 b) zinc oxide 0.35 3 c) crushed glass 0.75 4 d) glass beads 4.0 4 e) ground 1-, 0 4 sand f) iron powder 0.35 4 g) cupric oxide 0.35 4 in the same way other fillers including fibrous materials and threads made of metal, ceramics, carbon and glass incorporated into the polymelamines according to the invention.

PATENT CLAIMS:

Claims (4)

PATENT CLAIMS 1) Thermosetting polymers of the polymelamine type in which all of the amino groups bonded to the triazine rings have substituents, characterized in that they consist essentially of recurring units or segments of the general formula: wherein R¹ and R² each represent a lower alkyl group, a cyclone lower alkyl group or an aryl or alkaryl group, each of which is optionally substituted by one or two chlorine or one to three fluorine atoms or by a lower perfluoroalkyl group, a lower alkoxy group or an aralkoxy group; and wherein R³, R³ 'and, which can be the same or different, are divalent arylene radicals of the formula: are, where p is zero or 1 and n is zero or 1 and, if n is 1, X corresponds to the following formula: wherein m is an integer from 1 to 20, while Y is of the formula: and R4 and R5 are each a hydrogen atom, a lower alkyl or the phenyl group; and that the polymers are in the thermoset, crosslinked, insoluble state or in the "B" state in which they have an average molecular weight of 300 to 3,000. 2) Polymelamine type polymers according to claim 1 in the "B" state, thereby It is not noted that it is in a thermoplastic, in methylene chloride be in soluble form, contain a Lewis acid catalyst and are suitable, to be finally cured by further heating. Process for the preparation of the polymelamine polymers according to Claim 1, characterized in that a compound of the general formula: heated, where in the formula the substituents have the following meanings: R¹ and R² are each a lower alkyl group, a cyclone lower. -aikylgruppe or an aryl or alkaryl group, each of which is substituted by one or two chlorine or one to three fluorine atoms or by a lower perfluoroalkyl, a lower alkoxy or an alkoxy group; R3 is a divalent arylene radical of the formula: where p is zero or 1 and n is 0 or 1 and, if n is 1, X of the formula: where m is an integer from 1 to 20, while Y has the formula: is equivalent to; and R4 and R5 are each a hydrogen atom, a lower alkyl group or the phenyl group. 4) Method according to claim 3 for the production of the polymers according to claim 2, by noting that heating is interrupted when that average molecular weight of the polymer is about 300 to 3,000.