EP0311566A2
Expired / Lapsed
EP
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Thermotropic biphilic hydrogels and hydroplastics
Assignee: Novartis AG
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Filing: 1988-09-28
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Granted: —
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Expires: 2008-09-28
Abstract
Abstract Novel hydrogels and hydroplastics are described which exhibit temperature-dependent reversible phase-separations and clear-opaque transitions between about 0 and about 50°C. These materials consist of linear or crosslinked water-swollen, but water-insoluble, random compolymers of N,N-dimethylacrylamide with alkyl acrylates containing an average of at least 1.2 carbon atoms in the alkyl group. The water swelling of these polymers is extremely temperature dependent; they show sharply defined clear to opaque transitions in their water swollen state. They are useful in drug delivery systems, absorption and extraction processes and as qualitative thermometers, thermosensors and self-activating sunscreens, for example for greenhouses.
Inventors
- 👤 Karl F. Müller
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 18:59
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/52; C08F220/54; C08F220/10; C08F220/12; C08F220/16; C08F220/18; C08F220/1802; C08F220/1803; C08F220/1804; C08F220/1808; C08F220/1809; C08F220/1811; C08F220/1818; C09; C09K; C09K9/00; C09K9/02
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
108 words
A random copolymer which comprises the copolymerization product of (a) 10 to 85 % by weight of N,N-dimethylacrylamide; (b) 90 to 15 % by weight of an aliphatic, cycloaliphatic, aromatic or araliphatic hydrocarbyl acrylate or mixture thereof which contains an average of 1.2 to 18 carbon atoms in the hydrocarbyl moiety; (c) 0 to 5 % by weight of a polyolefinic crosslinking monomer, and (d) 0 to 30 % by weight of one or more monomers other than the acrlates of component (b), with the proviso, that if the average chain-length of the hydrocarbyl moiety is less than 5 carbon atoms, the polymer is uncrosslinked (c is zero).
Claim 2
Dependent Claim
108 words
A random copolymer which comprises the copolymerization product of (a) 10 to 85 % by weight of N,N-dimethylacrylamide; (b) 90 to 15 % by weight of an aliphatic, cycloaliphatic, aromatic or araliphatic hydrocarbyl acrylate or mixture thereof which contains an average of 1.2 to 18 carbon atoms in the hydrocarbyl moiety; (c) 0 to 5 % by weight of a polyolefinic crosslinking monomer, and (d) 0 to 30 % by weight of one or more monomers other than the acrlates of component (b), with the proviso, that if the average chain-length of the hydrocarbyl moiety is less than 5 carbon atoms, the polymer is uncrosslinked (c is zero).
Claim 3
Dependent Claim
14 words
A copolymer according to claim 1 wherein component (d) is 0 % by weight.
Claim 4
Dependent Claim
91 words
A copolymer according to claim 1 which comprises the copolymerization product of (a) 20 to 75 % by weight of N,N-dimethylacrylamide, (b) 80 to 25 % by weight of an alkyl or cycloalkyl acrylate or mixture thereof which contains an average of 1.25 to 12 carbon atoms in said alkyl or cycloalkyl moiety, and (c) 0 to 1 % by weight of a polyolefinic crosslinking monomer, with the proviso, that if the average chain-length of the hydrocarbyl moiety is less than 5 carbon atoms, the polymer is uncrosslinked (c is zero).
Claim 5
Dependent Claim
66 words
A copolymer according to claim 1 which comprises the copolymerization product of (a) 25 to 65 % by weight of N,N-dimethacrylamide, (b) 75 to 35 % by weight of an alkyl or cycloalkyl acrylate or mixture thereof which contains an average of 6 to 10 carbon atoms in said alkyl or cycloalkyl moiety, and (c) 0 to 0.5 % by weight of a polyolefinic crosslinking monomer.
Claim 6
Dependent Claim
51 words
A copolymer according to claim 1 which comprises the copolymerization product of (a) 25-65 % by weight of N,N-dimethyl acrylamide, and (b) 75-35 % by weight of an alkyl acrylate or mixture thereof which contains an average of 1.25-5 carbon atoms in said alkyl moiety, and wherein component (c) is zero.
Claim 7
Dependent Claim
25 words
A copolymer according to claim 1 wherein the hydrocarbyl moiety in the acrylate of component (b) is a cycloaliphatic group 6 to 12 carbon atoms.
Claim 8
Dependent Claim
30 words
A copolymer according to claim 1 which is prepared in the presence of 1 to 10 mol %, based on the total olefinic monomers polymerized, of a chain transfer agent.
Claim 9
Dependent Claim
14 words
A copolymer according to claim 2 wherein component (c) is 0 % by weight.
Claim 10
Dependent Claim
15 words
A copolymer according to claim 3 wherein the component (c) is 0 % by weight.
Claim 11
Dependent Claim
14 words
A copolymer according to claim 4 wherein component (c) is 0 % by weight.
Claim 12
Dependent Claim
45 words
A composition exhibiting a reversible temperature dependent clear to opaque transition between 0°C and 50°C, which comprises (a) 10 to 98 % by weight of water, and (b) 90 to 2 % by weight of a crosslinked or linear water-swellable copolymer according to claim 1.
Claim 13
Dependent Claim
95 words
A composition exhibiting a reversible temperature dependent clear to opaque transition between 0°C and 50°C, which comprises (a) 10 to 99.5 % by weight of water, and (b) 90 to 0.5 % by weight of a substantially uncrosslinked polymer which polymer is soluble in water below the cloud point and which comprises the copolymerization product of (a) 25-65 % by weight of N,N-dimethyl acrylamide, and (b) 75-35 % by weight of an alkyl acrylate or mixture thereof which contains an average of 1.25-5 carbon atoms in said alkyl moiety, and wherein component (c) is zero.
Claim 14
Dependent Claim
95 words
A composition exhibiting a reversible temperature dependent clear to opaque transition between 0°C and 50°C, which comprises (a) 10 to 99.5 % by weight of water, and (b) 90 to 0.5 % by weight of a substantially uncrosslinked polymer which polymer is soluble in water below the cloud point and which comprises the copolymerization product of (a) 25-65 % by weight of N,N-dimethyl acrylamide, and (b) 75-35 % by weight of an alkyl acrylate or mixture thereof which contains an average of 1.25-5 carbon atoms in said alkyl moiety, and wherein component (c) is zero.
Claim 15
Dependent Claim
29 words
A composition according to claim 11 which additionally contains 0.5 to 30 % by weight of an organic solvent which has at least a 1 % solubility in water.
Claim 16
Dependent Claim
29 words
A composition according to claim 12 which additionally contains 0.5 to 30 % by weight of an organic solvent which has at least a 1 % solubility in water.
Claim 17
Dependent Claim
16 words
A composition according to claim 11, in which the aqueous phase consists of a poly-acrylamide gel.
Claim 18
Dependent Claim
16 words
A composition according to claim 12, in which the aqueous phase consists of a poly-acrylamide gel.
Claim 19
Dependent Claim
16 words
A composition according to claim 13, in which the aqueous phase consists of a poly-acrylamide gel.
Claim 20
Dependent Claim
16 words
A composition according to claim 14, in which the aqueous phase consists of a poly-acrylamide gel.
References Cited (Backward Citations)
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