Energy absorbing polyurethane compositions

Claim 2

A polyurethane elastomer composition having a density of from about 0.4 to about 1 gm/cc, compression set of less than about 5% and a recovery time of from about 10 to about 600 milliseconds.

Claim 3

A polyurethane elastomer composition in accordance with Claim 1 wherein said recovery time is from about 15 to about 40 milliseconds.

Claim 4

A polyurethane elastomer composition in accordance with Claim I wherein said recovery time is from about 15 to about 25 milliseconds.

Claim 5

A polyurethane elastomer composition in accordance with Claim 1 wherein said compression set is less than about 1.5%.

Claim 6

A polyurethane elastomer composition in accordance with Claim 1 wherein said density is from about 0.6 to less than 1 gm/cc.

Claim 7

A polyurethane elastomer composition in accordance with Claim 1 wherein said density is from about 0.6 to about 0.7 gm/cc.

Claim 8

A polyurethane elastomer composition according to Claim 1 containing a light-weight filler material and being the reaction product of (a) a urethane-forming component comprising a compound containing at least four urethane-forming reactive sites and capable of forming stable complexes through unreacted urethane-forming reactive sites, an elasticising polyol selected from the group consisting of diols and triols, and (b) a diisocyanate in less than stoichiometric amounts.

Claim 9

A polyurethane elastomer composition according to Claim 7 wherein a portion of said elasticising polyol is replaced by a plasticiser.

Claim 10

A polyurethane elastomer composition according to Claim 7 or 8 wherein said reaction is catalysed by an added catalyst.

Claim 11

A polyurethane elastomer composition according to Claim 7 or 8 wherein said unreacted urethane-forming reactive sites are stabilised by chelation.

Claim 12

A polyurethane elastomer composition according to Claim 10 wherein said chelation is effected by ionic species.

Claim 13

A polyurethane elastomer composition according to Claim 11 wherein said ionic species are introduced as part of an added catalyst system.

Claim 14

A polyurethane elastomer composition according to Claim 11 wherein said ionic species are introduced separately from any added catalyst system.

Claim 15

A polyurethane elastomer composition according to Claim 9 wherein said catalyst is an organic catalyst.

Claim 16

A polyurethane elastomer composition according to Claim 14 wherein said unreacted urethane-forming sites are stabilised by chelation with ionic species from a source other than the added catalyst.

Claim 17

A polyurethane elastomer composition according to Claim 12 wherein the catalyst is selected from the group consisting of 2-ethyl-zinc hexanoate, phenyl mercury acetate, phenyl mercury laurate, cobalt octoate or butyl-tin-dilaurate.

Claim 18

A polyurethane elastomer composition according to Claim 15 wherein said ionic species are selected from the group consisting of Ag+, K+, Cu++, Hg++ and Ca++.

Claim 19

A polyurethane elastomer composition according to Claim 7 or 8 wherein said compound containing at least four urethane-forming reactive sites is a tetrol.

Claim 20

A polyurethane elastomer composition according to Claim 18 wherein said polurethane elastomer composition is the reaction production of about 1 part tetrol, about 1 to 3 parts elasticising polyol, about 0.2 to 2 parts filler, about 0 to 0.5 parts plasticiser and aromatic diisocyanate present in amounts such that the weight ratio of all other reactive components, plasticiser and filler to diisocyanate is from about 4:1 to about 10:1.

Claim 21

A polyurethane elastomer composition according to Claim 19 wherein the urethane-forming component of said polyurethane elastomer composition comprises about 1 part tetrol, about 2 parts elasticising diol, about 0.5 parts filler and about 0.25 parts plasticiser.

Claim 22

A polyurethane elastomer composition according to Claim 7 or 8 wherein said elasticising polyol is a diol.

Claim 23

A polyurethane elastomer composition according to Claim 21 wherein said diol is a polyalkylene ether glycol with molecular weight from about 450 to about 2000.

Claim 24

A polyurethane elastomer composition according to Claim 7 or 8 wherein said urethane-forming reactive sites are selected from the group consisting of hydroxyl groups and carboxyl groups.

Claim 25

A polyurethane elastomer composition according to Claim 18 wherein the tetrol has a molecular weight from about 170 to about 450.

Claim 26

A polyurethane elastomer composition according to Claim 20 wherein said tetrol has a molecular weight of about 200 and said diol has a molecular weight of about 2000.

Claim 27

A polyurethane elastomer composition according to Claim 8 wherein said plastiser reduces the normal intermolecular forces of the macromolecules and is selected from the group consisting of adipate, phosphate and phthalate esters.

Claim 28

A polyurethane elastomer composition according to Claim 7 or 8 wherein said filler material is about 40 to about 700 microns in diameter and is selected from the group consisting of hollow glass spheres, silicon dioxide spheres, fly ash and sintered silicon dioxide powder.

Claim 29

A polyurethane elastomer composition according to Claim 27 wherein said filler material is coated with an adhesion promoter.

Claim 30

A polyurethane elastomer composition according to Claim 25 wherein said filler material is coated silicone dioxide fly ash spheres about 70 microns in diameter and said plasticiser is dioctyl phthalate.

Claim 31

A polyurethane elastomer composition according to Claim 7 or 8 wherein said ratio is from about 6:1 to about 7:1.

Claim 32

A polyurethane elastomer according to Claim 24 wherein said tetrol is of the following formula: wherein n is an integer from 1 to 4; X 1 , X 2 , X 3 , and X 4 , are hydroxyl groups; and R , R 2 , R 3 , and R , which may the same or different, are alkyl groups with from 1 to 3 carbon atoms.

Claim 33

A polyurethane elastomer composition according to Claim 7 or 8 wherein at least 20% of available reactive sites remain unreacted.

Claim 34

A polyurethane elastomer composition according to Claim 32 wherein said unreacted sites are stablised by chelation.

Claim 35

A polyurethane elastomer composition according to Claim 30 wherein said diisocyanate is 4,4'-diphenylmethane diisocyanate.

Claim 36

A process for forming a polyurethane elastomer composition comprising: (a) mixing about 1 part of a compound having at least four urethane-forming reactive sites and capable of forming stable complexes through unsatisfied urethane-forming reactive sites, about 1 to about 3 parts of an elasticising polyol selected from the group consisting of diols and triols, about 0.2 to about 2 parts of light weight reinforcing filler selected from the group consisting of hollow glass spheres, silicon dioxide spheres, fly ash, and sintered silicon dioxide powder, and from 0 to about 0.5 parts plasticiser; (b) adding a diisocyanate in amounts such that the ratio of the weight of all other reactive components, filler and plasticiser to diisocyanate is in the range of from about 8.5:1 to about 11:1; (c) allowing formation of urethane linkages involving less than about 80% of the urethane-forming reactive sites on said compound having at least four such reactive sites; and (d) stabilising the remaining urethane-forming reactive sites by formation of complexes such that the cured product has a density of from about 0.4 to 1 gm/cc, a compression set of less than about 5% and a recovery time of from about 10 to about 100 milliseconds.

Claim 37

A process for forming a polyurethane elastomer composition comprising: (a) mixing about 1 part of a compound having at least four urethane-forming reactive sites and capable of forming stable complexes through unsatisfied urethane-forming reactive sites, about 1 to about 3 parts of an elasticising polyol selected from the group consisting of diols and triols, about 0.2 to about 2 parts of light weight reinforcing filler selected from the group consisting of hollow glass spheres, silicon dioxide spheres, fly ash, and sintered silicon dioxide powder, and from 0 to about 0.5 parts plasticiser; (b) adding a diisocyanate in amounts such that the ratio of the weight of all other reactive components, filler and plasticiser to diisocyanate is in the range of from about 8.5:1 to about 11:1; (c) allowing formation of urethane linkages involving less than about 80% of the urethane-forming reactive sites on said compound having at least four such reactive sites; and (d) stabilising the remaining urethane-forming reactive sites by formation of complexes such that the cured product has a density of from about 0.4 to 1 gm/cc, a compression set of less than about 5% and a recovery time of from about 10 to about 100 milliseconds.

Claim 38

An article of footwear having an energy absorbing element formed from the polurethane elastomer of Claim 7 or 8.

Claim 39

A shock absorbing insole formed from the polyurethane elastomer of Claim 7 or 8.

Claim 40

A constrained layer vibration damper comprising a laminate of relatively rigid exterior layers and an interior layer formed from the polyurethane elastomer of Claim 7 or 8.