US5098985A
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US
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Copolymers containing polybenzoxazole, polybenzothiazole and polybenzimidazole moieties
Assignee: Toyobo Co Ltd
•
Filing: 1990-05-08
•
Granted: 1992-03-24
•
Expires: 2010-05-08
Abstract
Abstract Block copolymers can be formed from heterocyclic polymers such as PBO and thermoplastic polymers such as polyamide or poly(aromatic ether ketone). The block copolymer compositions are thermoplastic and do not experience substantial phase separation, even at about their glass transition temperature. The block copolymer compositions can be formed into fibers, films and laminate or compression-molded articles. PBO, PBI and PBT polymers terminated by active aromatic rings or acylating groups are particularly useful for making the block copolymers.
Inventors
- 👤 William J. Harris
- 👤 Wen-Fang Hwang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:29
CPC Classifications
C; C08; C08G; C08G81/00; C08G65/00; C08G65/34; C08G65/38; C08G65/40; C08G65/4012; C08G73/00; C08G73/06; C08G73/18; C08G73/22; C08G75/00; C08G75/32; C08L; C08L71/00; C08L2205/00; C08L2205/05
Claims Analysis
Total Claims: 74
Claim 1
Independent Claim
48 words
A block copolymer comprising: (1) a polybenzazole block having on average at least about ten mer units; and (2) a thermoplastic block linked to said polybenzazole block containing a polyamide, polyimide, polyquinoxaline, polyquinoline, poly(aromatic ketone), poly(aromatic sulfone) or poly(aromatic ether) or a copolymer of one of those polymers.
Claim 2
Dependent Claim
48 words
A block copolymer comprising: (1) a polybenzazole block having on average at least about ten mer units; and (2) a thermoplastic block linked to said polybenzazole block containing a polyamide, polyimide, polyquinoxaline, polyquinoline, poly(aromatic ketone), poly(aromatic sulfone) or poly(aromatic ether) or a copolymer of one of those polymers.
Claim 3
Dependent Claim
25 words
The block copolymer of claim 1 wherein the polybenzazole block contains AB-PBZ mer units, that contain an aromatic group fused with a single azole ring.
Claim 4
Dependent Claim
20 words
The block copolymer of claim 2 wherein the mer units in the polybenzazole block are polybenzoxazole or polybenzothiazole mer units.
Claim 5
Dependent Claim
16 words
The block copolymer of claim 3 wherein the polybenzazole block consists essentially of AB-PBZ mer units.
Claim 6
Dependent Claim
49 words
The block copolymer of claim 4 wherein each AB-PBZ mer unit in the polybenzazole block is represented by the Formula: ##STR66## or the variation in which the nitrogen atom is para to the bond and the Z moiety is meta, wherein Z is an oxygen or a sulfur atom.
Claim 7
Dependent Claim
48 words
The block copolymer of claim 1 wherein the polybenzazole block contains both AB-PBX mer units and AA/BB-PBZ mer units, wherein the AB-PBZ mer units contain an aromatic group fused with a single azole ring and the AA/BB-PBZ mer units contain an aromatic group fused with two azole rings.
Claim 8
Dependent Claim
24 words
The block copolymer of claim 1 wherein the polybenzazole block contains AA/BB-PBZ mer units, that contain an aromatic group fused with two azole rings.
Claim 9
Dependent Claim
19 words
The block copolymer of claim 7 the mer units in the polybenzazole block are polybenzoxazole or polybenzothiazole mer units.
Claim 10
Dependent Claim
16 words
The block copolymer of claim 8 wherein the polybenzazole block consists essentially of AA/BB-PBZ mer units.
Claim 11
Dependent Claim
55 words
The block copolymer of claim 9 wherein each AA/BB-PBZ mer unit in the polybenzazole block is represented by the Formula: ##STR67## wherein Ar 1 is an aromatic group, each Z is an oxygen atom or a sulfur atom, and DL is a divalent organic moiety which is insert under conditions suitable to synthesize polybenzazole polymers.
Claim 12
Dependent Claim
15 words
The block copolymer of claim 10 wherein the polybenzazole block consists essentially of AA/BB-mer units.
Claim 13
Dependent Claim
16 words
The block copolymer of claim 11 wherein the polybenzazole block is not a rigid rod block.
Claim 14
Dependent Claim
15 words
The block copolymer of claim 11 wherein the polybenzazole block is a rigid rod block.
Claim 15
Dependent Claim
22 words
The block copolymer of claim 13 wherein each mer unit in the polybenzazole block is represented by one of the Formulae: ##STR68##
Claim 16
Dependent Claim
21 words
The block copolymer of claim 14 wherein each polybenzazole block contains on average between about 10 and about 150 mer units.
Claim 17
Dependent Claim
19 words
The block copolymer of claim 1 wherein each polybenzazole block contains on average at least about 20 mer units.
Claim 18
Dependent Claim
20 words
The block copolymer of claim 1 wherein each polybenzazole block contains on average no more than about 150 mer units.
Claim 19
Dependent Claim
20 words
The block copolymer of claim 1 wherein each polybenzazole block contains on average no more than about 50 mer units.
Claim 20
Dependent Claim
26 words
The block copolymer of claim 1 wherein each aromatic group in the polybenzazole block is a carbocyclic group containing no more than about 12 carbon atoms.
Claim 21
Dependent Claim
16 words
The block copolymer of claim 1 wherein the thermoplastic block contains polyamide or a copolymer thereof.
Claim 22
Dependent Claim
56 words
The block copolymer of claim 20 wherein the thermoplastic block is represented by the Formula: ##STR69## wherein A 1 and A 2 are each respectively a first and a second divalent organic moiety which is stable in solvent acid up to about 50° C., and b is a number of repeating mer units greater than 1.
Claim 23
Dependent Claim
19 words
The block copolymer of claim 21 wherein the one divalent organic moiety is aromatic and the other is aliphatic.
Claim 24
Dependent Claim
20 words
The block copolymer of claim 21 wherein at least one of A 1 or A 2 contains an ether moiety.
Claim 25
Dependent Claim
16 words
The block copolymer of claim 1 wherein the thermoplastic block contains polyimide or a copolymer thereof.
Claim 26
Dependent Claim
28 words
The block copolymer of claim 24 wherein the thermoplastic block is a copolymer containing imide moieties and moieties which enhance the solubility of the copolymer in solvent acid.
Claim 27
Dependent Claim
14 words
The block copolymer of claim 25 wherein the thermoplastic block is a poly(amide-imide) copolymer.
Claim 28
Dependent Claim
14 words
The block copolymer of claim 26 wherein the thermoplastic block contains a poly(imide-ether) copolymer.
Claim 29
Dependent Claim
15 words
The block copolymer of claim 1 wherein the thermoplastic block contains polyquinoline or copolymer thereof.
Claim 30
Dependent Claim
16 words
The block copolymer of claim 1 wherein the thermoplastic block contains polyquinoxaline or a copolymer thereof.
Claim 31
Dependent Claim
24 words
The block copolymer of claim 1 wherein the thermoplastic block contains a poly(aromatic ketone), poly(aromatic sulfone) or poly(aromatic ether) polymer or a copolymer thereof.
Claim 32
Dependent Claim
56 words
The block copolymer of claim 30 wherein the thermoplastic block contains a plurality of mer units while each comprise: 1) a first plurality of aromatic groups; 2) a number of decoupling groups sufficient to link the first plurality of aromatic groups; and 3) a first carbonyl or sulfonyl group bonded to one of the aromatic groups.
Claim 33
Dependent Claim
47 words
The block copolymer of claim 31 wherein the thermoplastic block is represented by the Formula: Ar--D--Ar--Y.sub.b -- wherein each Ar is an aromatic group, D is a decoupling group, Y is a carbonyl or sulfonyl moiety, and b is a number of repeating units greater than 1.
Claim 34
Dependent Claim
61 words
The block copolymer of claim 32 wherein the thermoplastic block is represented by the Formula: (Ar--J).sub.n --Ar--Y.sub.b -- wherein each J is individually an oxygen atom, a sulfur atom or a bond, and n is a number a number of repeating units equal to 1 or more, each chosen such that at least one J is an oxygen or sulfur atom.
Claim 35
Dependent Claim
32 words
The block copolymer of claim 33 wherein n is at least 2 and each J is individually oxygen or a bond chosen such that at least one J is an oxygen atom.
Claim 36
Dependent Claim
44 words
The block copolymer of claim 31 wherein the mer units of the thermoplastic block further comprise: 4) a divalent organic moiety (T) bonded to the first carbonyl or sulfonyl group; and 5) a second carbonyl or sulfonyl group bonded to the divalent organic moiety.
Claim 37
Dependent Claim
57 words
The block copolymer of claim 35 wherein the thermoplastic block is represented by the Formula: Ar--D--Ar--Y--T--Y.sub.b wherein each Ar is an aromatic group, D is a decoupling group, T is a divalent organic moiety which contains a decoupling group, Y is a carbonyl or sulfonyl moiety, and b is a number of repeating units greater than 1.
Claim 38
Dependent Claim
61 words
The block copolymer of claim 35 wherein the thermoplastic block is represented by the Formula: Ar--J.sub.n --Ar--Y--T--Y.sub.b -- wherein each J is individually an oxygen atom, a sulfur atom or a bond, and n is a number a number of repeating units equal to 1 or more, each chosen such that at least one J is an oxygen or sulfur atom.
Claim 39
Dependent Claim
32 words
The block copolymer of claim 37 wherein n is at least 2 and each J is individually oxygen or a bond chosen such that at least one J is an oxygen atom.
Claim 40
Dependent Claim
14 words
The block copolymer of claim 38 wherein T is represented by the Formula: --Ar--J--Ar--.
Claim 41
Dependent Claim
20 words
The block copolymer of claim 30 wherein at least some mer units in the thermoplastic block further contain amide moieties.
Claim 42
Dependent Claim
20 words
The block copolymer of claim 30 wherein at least some mer units in the thermoplastic block further contain benzazole moieties.
Claim 43
Dependent Claim
95 words
The block copolymer of claim 41 wherein the thermoplastic block contains a plurality of units which each individually comprise: 1) a first plurality of aromatic groups; 2) a number of decoupling group sufficient to link the plurality of aromatic groups; 3) a first carbonyl or sulfonyl group bonded to one of the aromatic groups; 4) a divalent organic moiety (T) bonded to the first carbonyl or sulfonyl group; and 5) a second carbonyl or sulfonyl group bonded to the divalent organic moiety wherein at least some of the divalent organic moieties (T) contain benzazole moieties.
Claim 44
Dependent Claim
93 words
The block copolymer of claim 41 wherein the thermoplastic block contains a plurality of units which each individually comprise: 1) a first plurality of aromatic groups; 2) a number of decoupling group sufficient to link the plurality of aromatic groups; 3) a first carbonyl or sulfonyl group bonded to one of the aromatic groups; 4) a divalent organic moiety (T) bonded to the first carbonyl or sulfonyl group; and 5) a second carbonyl or sulfonyl group bonded to the divalent organic moiety wherein at least some of the decoupling groups contain benzazole moieties.
Claim 45
Dependent Claim
23 words
The block copolymer of claim 41 wherein each repeating unit of the thermoplastic block contains on average between 0.1 and 3 benzazole units.
Claim 46
Dependent Claim
108 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR70## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800.
Claim 47
Dependent Claim
124 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula; ##STR71## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula; --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 48
Dependent Claim
124 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR72## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3;
Claim 49
Dependent Claim
124 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR73## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 50
Dependent Claim
124 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR74## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 51
Dependent Claim
136 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR75## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic bock exceeds 800; "b" represents a number of repeating units which averages between about 0.1 and about 3; and "c" represents a number of repeating units which averages less than 10.
Claim 52
Dependent Claim
148 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR76## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; DM represents a divalent moiety which is inert with respect to all reagents under conditions at which the thermoplastic block is synthesized and used; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 53
Dependent Claim
102 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR77## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "d" and "e" each represents a number of repeating units which averages less than about 10.
Claim 54
Dependent Claim
160 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR78## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; DM represents a divalent moiety which is inert with respect to all reagents under conditions at which the thermoplastic block is synthesized and used; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; "b" represents a number of repeating units which averages between about 0.1 and about 3; and "d" represents a number of repeating units which averages less than 10.
Claim 55
Dependent Claim
124 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR79## wherein: each Y represents a carbonyl or sulfonyl moiety; each DB represents either a decoupling group or a bond; each D represents a decoupling group; each Ar represents an aromatic group; each Z represents a moiety of the formula: --O--, --S-- or --NR--, wherein each R is independently a hydrogen atom or an organic moiety which is inert in solvent acid under conditions at which the polymer is synthesized; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 56
Dependent Claim
121 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR80## wherein each Ar individually represents an aromatic moiety comprising no more than about 12 carbon atoms; each Z individually represents a moiety having the formula --O-- or --S--; each Y individually represents a sulfonyl or carbonyl moiety; each J represents an oxygen atom or a bond, chosen such that when an aromatic group is bonded to 2 J moieties, at least one is an oxygen atom; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 57
Dependent Claim
121 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR81## wherein each Ar individually represents an aromatic moiety comprising no more than about 12 carbon atoms; each Z individually represents a moiety having the formula --O-- or --S--; each Y individually represents a sulfonyl or carbonyl moiety; each J represents an oxygen atom or a bond, chosen such that when an aromatic group is bonded to 2 J moieties, at least one is an oxygen atom; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceed 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 58
Dependent Claim
121 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR82## wherein each Ar individually represents an aromatic moiety comprising no more than about 12 carbon atoms; each Z individually represents a moiety having the formula --O-- or --S--; each Y individually represents a sulfonyl or carbonyl moiety; each J represents an oxygen atom or a bond, chosen such that when an aromatic group is bonded to 2 J moieties, at least one is an oxygen atom; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 59
Dependent Claim
135 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR83## wherein each Ar individually represents an aromatic moiety comprising no more than about 12 carbon atoms; each Z individually represents a moiety having the formula --O-- or --S--; each Y individually represents a sulfonyl or carbonyl moiety; each J represents an oxygen atom or a bond, chosen such that when an aromatic group is bonded to 2 J moieties, at least one is an oxygen atom; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; "b" represents a number of repeating units which averages between about 0.1 and about 3; and "c" represents a number of repeating units which averages no more than about 10.
Claim 60
Dependent Claim
121 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR84## wherein each Ar individually represents an aromatic moiety comprising no more than about 12 carbon atoms; each Z individually represents a moiety having the formula --O-- or --S--; each Y individually represents a sulfonyl or carbonyl moiety; each J represents an oxygen atom or a bond, chosen such that when an aromatic group is bonded to 2 J moieties, at least one is an oxygen atom; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 61
Dependent Claim
121 words
The block copolymer of claim 44 wherein the thermoplastic block is represented by the average Formula: ##STR85## wherein each Ar individually represents an aromatic moiety comprising no more than about 12 carbon atoms; each Z individually represents a moiety having the formula --O-- or --S--; each Y individually represents a sulfonyl or carbonyl moiety; each J represents an oxygen atom or a bond, chosen such that when an aromatic group is bonded to 2 J moieties, at least one is an oxygen atom; "a" represents a number of repeating units which is chosen such that the average Formula weight of the thermoplastic block exceeds 800; and "b" represents a number of repeating units which averages between about 0.1 and about 3.
Claim 62
Dependent Claim
23 words
The block copolymer of claim 44 wherein at least some repeating units in the thermoplastic block also contain one or more amide moieties
Claim 63
Dependent Claim
50 words
The block copolymer of claim 1 comprising a moiety which is represented by the formula PBZ--L--thermoplastic--).sub.c wherein (PBZ) represents a PBZ block; (thermoplastic) represents a thermoplastic block; each L is either a bond or a linking group; and c is a number of repeating units at least equal to one.
Claim 64
Dependent Claim
62 words
The block copolymer or claim 62 wherein each L comprises a moiety which conforms to a formula chosen from the group consisting of --D--Y--Ar--D--, --D--Y--Ar--(O--Ar).sub.n --Y--D-- or --D--Ar--Y--D--Y--Ar--D-- wherein each D is a decoupling group; each Y is a carbonyl or sulfonyl group; each Ar is an aromatic group; and n is a number of repeating units equal to one or more.
Claim 65
Dependent Claim
15 words
The block copolymer of claim 63 wherein each L is represented by the formula --Ar--O--Ar--Y--Ar--O--Ar--O--Ar--.
Claim 66
Dependent Claim
15 words
The block copolymer of clam 64 wherein each L is represented by the formula ##STR86##
Claim 67
Dependent Claim
15 words
The block copolymer of clam 64 wherein each L is represented by the formula ##STR86##
Claim 68
Dependent Claim
105 words
The block copolymer of claim 1 which comprises a moiety that is represented by the average structure in the formula: ##STR87## wherein: each Ar is an aromatic group; each Z is an oxygen atom, a sulfur atom, or a nitrogen atom bearing a hydrogen atom or an organic substituent, which may be in cis or trans position on Ar 1 ; m is a number of repeating units from 0 to 9 averaging from 1 to 3; a is a number of repeating PBX units; b is a number of repeating thermoplastic units; and c is a number of units equal to one or more.
Claim 69
Dependent Claim
60 words
The block copolymer of claim 1 which comprises a moiety that is represented on average by the formula: ##STR88## wherein: m is a number of repeating units averaging from 1 to 3; a is a number of repeating PBZ units; b is a number of repeating thermoplastic units; and c is a number of units equal to one or more.
Claim 70
Dependent Claim
28 words
The block copolymer of claim 1 wherein neither the PBZ block nor the thermoplastic block makes up less than about 5 percent of the block copolymer by weight.
Claim 71
Dependent Claim
28 words
The block copolymer of claim 1 wherein neither the PBZ block nor the thermoplastic block makes up less than about 30 percent of the block copolymer by weight.
Claim 72
Dependent Claim
16 words
The block copolymer of claim 1 which is end-capped by the remnant of a monofunctional reagent.
Claim 73
Dependent Claim
19 words
The block copolymer of claim 1 which exhibits a glass transition temperature below 400° C. under differential scanning calorimetry.
Claim 74
Dependent Claim
27 words
The block copolymer of claim 71 which can be heated to its glass transition temperature and then cooled below its glass transition temperature without substantial phase separation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-24 | 1995-09-23 | 1996-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-24 | 1999-09-23 | 2000-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-24 | 2003-09-23 | 2004-03-24 | $7700.00 | Window Closed / Lapsed |