AU602042B2 - Arylcyclobutene/dienophile copolymers - Google Patents

Description

AUSTRALIA

PatentIs Act frt\

F'

COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: !,.oclged: Complete Specification Lodged: Accepted-, Publishied: Priority Related Art: Ct' I h:~ a

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AVPI l('AN''S RIiF,: Dow Case No: 34, 953-F Namne(s) of Applicant(s): Address(es) of Applicant(s): Actual Inventor(s): Address for Service is: THE DOW CHEMICAL COMPANY 2030 Dow Center, Abbott RQade Mid1an1, Michigan 48640, UNITED STATES OF AMERICA Stephen V. Hahn Robert A. Kirchhoff PHI LLIPS, ORN40NDE AND FITZPATRICK Patent and Trade Nmrk. Attoirneys 367 Collins Street Melbourne, Australia, 3000 Complete Specification for the invention entitled: ARYLCYCLODUTENE/DIENOPHILE COPOLYMERS Thle following statement is a full description1 or' tis invention, including thle best method of performing it known to applicant(s): 111911 4 ARYLCYCLOBUTANE/DIENOPHILE

COPOLYMERS

This invention relates to arylcyclobutane copolymer compusitions.

000 0 a Q o Arylcyclobutane resins are a family of monomers, oligomers, prepolymers and polymers.

o0o1 4 Poly(arylcyclobutane) polymers are disclosed in U. S.

Patent 4,540,763. The polymers are prepared by heating 0 o0 a resin having two or more arylcyclobutane moieties to 10 temperatures sufficient to open the cyclobutane rings.

1 10 The opened cyclobutane rings react with each other to form a crosslinked polymer.

0a 4 The poly(arylcyclobutane) polymers exhibit excellent thermal and oxidative stability. They can be used as coatings, adhesives, composites and the like.

However, U. S. Patent 4,540,763 discloses that the polymers can only be prepared from arylcyclobutanecontaining monomers.

In view of the excellent properties exhibited have compounds and methods for preparing copolymers of arylcyclobutane monomers and other monomers.

34,953-F -1A- 1-lb- This invention is a polymer composition comprising, in polymerized form, a monomer containing at least two polymerizable arylcyclobutane moieties and a monomer containing at least two polymerizable dienophilic moieties.

As used herein and in the claims, the term "aryl" refers to an aromatic moiety which can suitably be either carbocyclic or heterocyclic in character.

o 00 4-4. .4 fl -2- This invenEton is a polymer composition comprising, in polymerized form, a mongmer6-ntaining at least two polymerizable.-a-ry-yclobutane moieties and a monomer cont ai-n-i'rgat least two polymerizable digneprhiic moieties.

roo 0 0 0000 000 o0000' 0ocoo 15 0 i The mixture of the dienophilic monomer and arylcyclobutane monomer provides a reactive monomer system which is useful in preparing copolymer compositions. The copolymer compositions can exhibit improved properties such as adhesion, thermal stability, solvent resistance, dielectric constant, etc. compared to homopolymer compositions prepared from either monomer. The copolymer compositions of this invention can be thermoplastic or thermoset polymeric compositions and can be used in conventional thermoplastic and thermoset applications. Examples of such uses include adhesives, coatings, composites and the like.

0~ 0 0 0a O 00 00 00 00 0 The aryloyclobutane monomers of this invention include monomers, prepolymers and oligomeric chains with at least two polymerizable arylcyclobutane moieties.. An arylcyclobutane moiety is polymerizable when addition polymerization sites are provided under ring-opening conditions. Suitable arylcyclobutane monomers, prepolymers and oligomers and their preparation are disclosed in U. S. Patent 4,540,763.

Methods of making the aryloyclobutane precursors are disclosed in U. S. Patents 4,562,280 and 4,570,011.

Preferably, the aryloyclobutane monomers are benzocyclobutane monomers, and can be represented by the formula: j 34,953-F -2- -3- ~I~i~H i i

I

j i

I

I i i ;i wherein R is a polyvalent organic or inorganic moiety, or a direct bond.

An aspecially preferred monomer is a reaction product of styrene and 4-vinylbenzocyclobutane. To prepare such a monomer styrene is contacted with 4vinylbenzocyclobutane in the presence of a suitable free-radical initiator, such as azobisisobutyronitrile.

The styrene and L-vinylbenzocyclobutane compounds are added in any amount sufficient to provide two polymerizable benzocyclobutane moietien. This monomer can be called poly(styrene-co-4-vinylbenzocyclobutane), and corresponds to the formula

(II)

25 OH OH 2 -OH _CH- CH 00 n 0 m wherein n and m are integers of at least 1.

A preferred benzocyclobutane monom, r having an R group containing aromtic ring. sn be prepared by 34,953-F -3- 1 4 -4contacting 4,4'-isopropylidene diphenol (bisphenol A) with 4 benzocyclobutane 4-carboxylic acid chloride in i the presence of triethylamine and methylene chloride.

j The bisphenol A and benzocyclobutane compounds are added in any amounts sufficient to provide two polymerizable benzocyclobutane moieties, and the R group corresponds to the formula

CH

3 (III) "0 C

CH

3 *0 0 x

O

wherein X is an integer of at least 1.

A preferred benzocyclobutane monomer having an R group containing amino groups can be prepared by contacting a diamino-alkane with 4-benzocyclobutane carboxylic acid. in the presence.of 1,1-carboxyldiimidazole. The diamino-alkane and benzocyclobutane compounds are added in any amounts sufficient to Sprovide two benzocyclobutane moieties, and the R group corresponds to the formula 34,953-F H H (Iv) C/N-(CH2)n

N

!I

0 0 X wherein n and x are integers of at least 1.

A preferred benzocyclobutane monomer having an R group containing unsaturated hydrocarbon groups can o 15 be prepared by contacting a divinylbenzene monomer with 4-bromobenzocyclobutane in the presence of a suitable palladium catalyst. The divinylbenzene and benzocyclobutane compounds are added in any amounts sufficient to provide two polymerizable benzocyclobutane moieties, and the R groups corresponds to the formula HH

(V)

C_

C

C=C

wherein x is an integer of at least 1.

A preferred benzocyclobutane monomer having an R group containing siloxane groups can be prepared by contacting 1,1,3,3-tetramethyl-1,3-divinyl disiloxane 34,5~3-F: with 4-bromobenzocyclobutane -the presence of a suitable palladium catalyst, the divinyl siloxane and benzocyclobutane compounds are added in any amounts sufficient to provide two polymerizable benZocyclobutane moieties, and the R group corresponds to the formula H CH 3

CH

3 H (VI) C=C- SI-0-Si- C=C

CH

3

CH

3 x wherein x is an integer of at least 1.

Many other benzocyclobutane monomers which can be employed as a monomer in this invention are disclosed in U. S. Patent 4,540,763.

The arylcyclobutane monomers can be heterocyclic aryloyclobutane monomers. Preferred heterocyclic arylcyolobutane monomers are Scyclobutapyridine monomers, which ideally correspond to the formula

(VII)

wherein R is as defined hereinbefore.

Methods for preparing cyQlobutapyridines and substbItuted eyalobutapyridines are disclosed by J. M.

34,953-F -6- .2O Riemann and W. S. Trahanovsky in Tetrahedron Letters, No. 22, pp. 1867-1870 (1977), (cyclobuta[b]pyridine and cyclobutalio]pyridine); and by W. D. Crow, A. N. Khan and M. N. Paddoa-Row in Australian Journal of Chemistr, No. 28, pp. 1741-1754 (1975), (2-methylcyclobuta[bJpyridine). Methods suitable for preparing other substituted cyclobutapyridines are suggested in the following references for the indicated compounds: in Organic Reactions, Vol. I, p. 91 (2-aminocyclobuta~bl- U0 pyridine); in Berichte, No. 57, p. 791, and p. 1802 (1924), (2-hydroxycyclobuta~blpyridine is prepared from 0a 2-aminocy( lobuta[blpyridine) by Hatinger and Lieben in Monatschaft, No. 6, p. 279 (1885), and Rath, Annalan hemische, No. 4l86, p. 71 (1931), (2-chiorocyclobuta~blpyridine is prepared from 2hydroxycyclobultalpyridine) The substituted heterocyclic arylcyclobutane compounds can be used to prepare heterocyclic aryloyclobutane monomers. For example, a maleamic acid derivative of cyclobutapyridine can be prepared by contacting 2-aminocyclobutapyr'ldine with maleic anhydride in the presence of a suitable organic solvent, such as chloroform, at suitable reaction temper'ptures. From about equal molar to about a greater molar amount of 2-arninocyclobutapyridile per maleic anhydride is employed. The maleamic acid derivative of cyolobutapyridine can be employed to prepare 2-(t-maleimido]cyclobutapynidine by treating the maleanijo acid, derivativ~e at suitable reaction temperatures In a suitable organic solvent, for example, sodium acetate in acetic acid. Suitable temperatures Include the range of 1000C to 12000., 34 1 953-F -7- In another example, 2-bromocyclobutapyridine can be employed to prepare 2-vinylcyclobutapyridines.

The bromocyclobutapyridine is contacted with excess ethylene at suitable pressure in the presence of a suitable catalyst system and solvent, and at suitable reaction temperatures. Suitable catalyst systems include palladium (II) acetate; and a suitable cocatalyst is tri-o-tolylphosphine. Suitable solvents o0 include acetonitrile, and suitable reaction oo o 10 temperatures inolude 125°C. The 2-vinylcyclobutapyridine can be contacted with styrene in the o presence of a free-radical initiator to provide a vinyl o t o, bridged poly(cyolobutapyridine).

In yet another example, 2-bromocyclobutapyridine can be employed to prepare a nonocylobutapyridine monomer having a vinyl bridging member connecting the oyclobutapyridine moiety with an organic Smolecular group, such as an aromatic moiety. For example, to prepare 1-(4-methyl-phenyl)-2-(2cyQlobutapy~fdyl)ethene, an amount of 2-bromooyclobutapyridine is contacted with a substantially equal to slightly greater molar amount of 4methylstyrene in the presence of a suitable catalyst system, in a suitable solvent under suitable reaction conditions. Suitable catalyst systems include palladium (II) acetate and a suitable cocatalyst includes tri-o-tolylphosphine. Suitable solvents -4 ^30 include acetonitrile, and suitable reaction conditions include refluxing for a sufficient time.

The dienophilio moieites are moieties which react with conjugated dienes to form a six-member ring.

Such moieties are discussed in Morrison and Boyd, Organic Chemistry, 3rd Ed., 1979. Suitable moieties 34,953-F -9are alkenyl moieties and preferably are unsaturated hydrocarbon moieties having an electron-withdrawing group on an adjacent carbon. Suitable electronwithdrawing groups are oxygen, nitrogen, halogens, phosphorous and the like. Especially preferred dienophilic moieties are a,b-unsaturated carbonyl compounds, and the most preferred moieties are maleimide moieties.

The more preferred monomers are monomers which contain polymerizable dienophilic moieties which polymerize at about within 50 0 C) of the tempera- Sture at which the arylcyolobutane-containing monomers polymerize. The most preferred monomers contain maleimide moieties. The maleimide-containing monomers polymerize at about 200°C. Such monomers can be repreo*o sented by the formula: o 0 (VIu) H c H G /c C~c S N- X NX-N Hc 0 0 Swherein X is a polyvalent organio or inorganio moiety.

Preferred X groups are: 34953-F -9- ~i L 1

(X)

Q o Q 100 (XI)

(XII)

H 0 H0 and -(CH)iT~ (xiii) wherein n is at least 1.

Methods of preparing such maleimicles are disclosed in Polymer, Vol. 26, p. 1561, September 1985.

Yet other pref~erred dienophilio moieties' are alk<ylene moieties, especially aoetylenio moieties, The amounts of' the arylcyclobutane-containing monomer and the dienophilic monomer which are employed In preparing the copolymers of this invention can vary.

The ary2loyclobutane monomer is employQd at less than 100 percent by weight of the monomers mixture, and the dienophilic monomer Is employed at le.'is than 100 peraent or' the monomer mixture. Preferably, If the cienophillo monomer polymerizes at a temperature below 341,953"F ,~li~r i ic-- e -11the polymerization temperature of the arylcyclobutane monomer, the ratio of the amount of dienophilic monomer to the amount of arylcyclobutane monomer is greater than one.

In addition to the arylcyc-obutane monomer and dienophilic monomer, the copolymer composition of this invention can be comprised of other monomeric or polymeric compositions which can independently a 10 polymerize to provide an interpenetrating network or aa"" can copolymerize with the monomers. Suitable optional monomeric or polymeric compositions include monoarylcyclobutane monomers monomers which contain only one arylcyclobutane moiety) and other poly(aryl- 15 cyclobutane) monomers monomers which contain at least two arylcyclobutane moieties). Preferred monoarylcyclobutanes are A,B-monomers which have a polymerizable benzocyclobutane moiety and a reactive maleimide moiety. Such monomers can correspond to the formula 0 Hac H i 0 wherein R' is a direct bond, or a polyvalent organic or inorganic moiety, and can be the same or different as R. Such A,B-mononiers can be prepared by dehydrating beizocyclobutenyl maleamic acid. The maleamic acid 34,953-F -11- -12derivatives and methods for preparing them are disclosed in U. S. Patent 4,638,078.

The copolymer composition can also contain optional components which are determined by the particular use of the copolymer. Such optional components include fibrous fillers such as glass, quartz and graphite fibers; organic and inorganic powder fillers; catalysts; curing agents; fire o 10 retardants; and the like. For example, the copolymer composition can contain an amount of an electroconductive metal such as silver or gold powder and can be used as a die-attach material. In another example, the copolymer composition can contain an amount of 15 S reinforcing glass fibers and can be used as a composite.

O 0 The copolymer composition is prepared by o^ combining the arylcyclobutane monomer and the dienophilic monomer to form a mixture and treating the monomer mixture at sufficient polymerization conditions. The monomer mixture can thermally S6 polymerize, so the application of heat is a preferred 0 0 25 polymerization process.

When preparing the most preferred copolymers from benzocyclobutane monomers and bismaleimide monomers, suitable polymerization temperatures are temperatures at which the oyclobutane rings open to provide a diene-type structure. Preferably such temperatures range from about 180 0 C to 270'C.

Ideally, the copolymers of th? ben-:oyclobutane Sand bismaleimide monomers can contain units which can be represented by the formula: 34,953-F -12- -13- R 0I N-X (x

C

C o S0 H 0 o' oo wherein R and X are as defined herein above, o Preparing the copolymers of this invention can o, improve the physical properties of homopolymers o 15 prepared from the monomers. For example, adhesion/thermal stability, solvent resistance, o dielectric constant, elongation at break (toughness), oio and the like can be improved. Also, surprisingly, the hot wet strength of the maleimide polymers can be increased.

The following example is an illustration and o does not limit the scope of the invention.

Example Copolymers-of Polyistyrene-co-4-vinylbenzooyclobutane) with the bismaleimide derived from 4,4'-diaminophenylether A blend of the 2 components of this system was prepared initially. This blend was prepared in a 500 ml 2-neck round bottom flask equipped with a gas inlet tube and positive nitrogen pressure provided with a mineral oil bubbler, magnetic stirrer and stopper.

To this was added 100 ml of dichloromethane and 25 g of poly(styrene-co-4-vinylbenzocyolobutane) (5 percent 4- 34,953-F -13- 0 0 0 0000 0 0 0 0 0? 0 0 &0 0 0 0 0 (0 0* 0 vinylbenzocyclobutane, 1.25 g 4-vinylbenzocyclobutane, MW=130.29, 0.0096 equivalents). This mixture was stirred until complete dissolution occurred. To this mixture was added 3.45 g 4,4'-diphenyl ether bismaleimide (MW=360,0.00958 moles) and 150 ml of dichloromethane. This mixture was stirred until complete dissolution occurred.

The yellow solution was poured into a cake pan 10 which has been covered with a Teflon® sheet, and the dichloromethane was allowed to evaporate in a fume hood overnight. The resultant homogeneous, bright yellow polymer sheet was cut into small pieces with scissors and these pieces were then ground using a Wiley laboratory mill. The ground polymer was then dried in a vacuum oven overnight (0.1 mm Hg, 100°C). This dried powder weighed 19.7 g, or 69 percent recovery.

Differential scanning calorimetry shows a glass transition at 86°C, and one major polymerization exotherm which peaks at 259.8°C.

A piece of heavy gauge alluminum foil was coated with a suitable mold release agent and placed on a flat steel plate with the coated surface facing up.

On top of this was plaped a steel plate, in which was cut a hole in the shape of a standard tensile test bar.

The assembly was then sprayed with a iiold release agent. The benzocyolobu'tane/bismaleimfide mixture was then placed in the mold shape, and the copolymer was pressed down :into the mold with a spatula. More copolymer was placed on top of this, and the copolymer was then covered with another piece of release-agenttreated aluminum foil and another steel plate. The apparatus was then entered into a hydraulic press which has been heated to 2100,, and the platens were closed 34,953-F -14until they just touch both plates. The mold was then allowed to sit for 10 minutes while the copolymer melted; the mold was then pressurized to 15 tons ram force. The mold was then heated to 255 0 C over 10 minutes. The mold was maintained between 250°C to 255°C for another 10 minutes. At the end of this time, the pressure was released and the molding apparatus was transferred from the hot press directly to a cold I' press, where the mold was allowed to cool for minutes. The copolymer part was then removed and was brown-orange in appearance, weighing 6.7 g.

The copolymer, containing 9.6 millimoles benzocyclobutane and 9.6 millimoles bismaleimide, exhibits a glass transition of 86 0 C prior to polymerization. The copolymer sample completely disintegrates in methylene chloride, whereas the copolymer obtained by thermally copolymerizing the bismaleimide and the polystyrene-co- -4-vinylbenzocyclobutane swells but does not dissolve or disintegrate.

A mixture of 7.5 percent vinylbenzocyclobutanecontaining polystyrene-co-4-vinylbenzooyclobutane with S1 mole of bismaleimide per mole benzocyclobutane gave a copolymer which exhibits'a glass transition prior to curing of 108°C to 111 0 C. The curing of this material by heating to 300 0 C gave a copolymer with a glass transition temperature from roughly 114 0 °C to 121 0

C.

30 Another sample of a mixture containing 5 percent benzocyclobutane and 3.85 millimoles bismaleimide was prepared and crosslinked by heating to 320'C. The uncured material exhibits a glass transition temperature of 89 0 C, while after curing, the glass transition temperature moves to 110 0 C. All of the samples of polystyrene-co-4-vinylbenzooyclobutane 34,953-F r -16admixed with bismaleimide exhibit a polymerization exotherm beginning at 190'C to 200 0 C and peaking near 250 0 C to 260 0

C.

C

C

C

C

QOCO

t. Li C 0 IL 00

C

C iii 34,1953-F -6

Claims (4)

1. A copolymer composition comprising, in polymerized form, a monomer containing at least two polymerizable arylcyclobutane moieties, and a monomer containing at least two polymerizable dienophilic moieties with the proviso that when the monomer containing at least two polymerizable dienophilic moieties corresponds to the formula: 0 II II H O O then the monomer containing at least two polymerizable arylcyclobutane moieties does not correspond to the formula; 0 0 I Hf CC CF 3 C CC CF 3 C H c c H I II 0 0

2. A copolymer composition as claimed in claim 1 wherein the arylcyclobutane moieties are benzocyclobutane moieties

3. A copolymer composition as claimed in claim 1 or claim 2 wherein the dienophilic moieties are alkenyl moieties. 2. A copolymer composition as claimed in claim 1 wherein the arylcyclobutane moieties are benzocyclobutane moieties, carbonyl moieties.

53. A copolymer composition as claimed in claim 1 or claim 2 wherein the dienophilic moieties are maleimide moieties. 6. A copolymer composition as claimed in claim 5 wherein 2 wherein the dienophilic moieties are x, -unsaturated carbonyl moieties. A copolymer composition as claimed in claim 1 or claim 2 wherein the dienophilic moieties are maleimide moieties. 6. A copolymer composition as claimed in claim 5 wherein the ratio of amount of the maleimide-containing monomer to benzocyclobutane-containing monomer is greater than 1. .=r~lrrr-.~l-r~i;ir I I-i: -18- 7. A copolymer composition as claimed in claim 1 wherein the monomer containing at least two polymerizable arylcyclobutane moieties is poly(styrene-co-4- Vinylbenzocyclobutane) and the monomer containing at least two polymerizable dienophilic moieties is 4,4'-diphenyl ether bismaleimide. 8. A copolymer composition as claimed in claim 1 wherein the monomer containing at least two polymerizable arylcyclobutane moieties is selected from the group consisting of poly (styrene-co-4-vir.nyl-benzocyclobutane) of the formula: -C2- CH CH2- CH CH 2 -CH 0 N n whereir. n and m are integers of at least 1; cyclobutapyridine monomers of the formula: wherein R" is a polyvalent organic or inorganic moiety or a direct bond; and benzocyclobutane monomers of the formula: R JM L1 -19- wherein R is a direct bond, a polyvalent inorganic moiety or a polyvalent organic moiety of the formula: CHI /00 C CHI 0 0 H H N-(CH2)n'-N 0 0 HH H H c~c c~c or HH j H H H CHI CHI WA, J7M i wherein x and n' are each integers of at least 1. 9. A copolymer composition as claimed in claim 1 substantially as hereinbefore described with reference to the example. DATED: 6 June, 1990 THE DOW CHEMICAL COMPANY By their Patent Attorneys: r 0 .r PHILLIPS ORMONDE FITZPATT