Splice for use during the thermal stabilization of a flat multifilament band of an acrylic fibrous material comprising at least two segments

Claim 2

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by bonding the substantially flat surfaces of said band segments together with a silicone rubber adhesive in a manner sufficient to provide a flexible splice, through which the exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation, wherein the ends of said band segments are disposed in an overlapped relationship with each of said band segments extending in an opposite direction with the silicone rubber being present on the upper and lower surfaces of said overlapping ends.

Claim 3

An improved process according to claim 1 wherein said multifilament band of an acrylic fibrous material is selected from the group consisting essentially of an acrylonitrile homopolymer and acrylonitrile copolymer which contain at least about 85 mole percent of acrylonitrile units and up to about 15 mole percent of one or more monovinyl units copolymerized therewith.

Claim 4

An improved process according to claim 1 wherein said multifilament band has a width of about 1 to 36 inches.

Claim 5

An improved process according to claim 1 wherein pressure is applied to the overlapping band segments of from about 5 to about 10 psig during cure of the silicone rubber adhesive.

Claim 6

An improved process according to claim 1 wherein the extent of the overlap of the terminal portions of the band segments having the silicone rubber present thereon is from about 3 to about 12 times the width of a band segment.

Claim 7

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by bonding the substantially flat surfaces of said band segments together with a room temperature vulcanizable silicone rubber in a manner sufficient to provide a flexible splice, through which said exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation, wherein the ends of said band segments are disposed in an overlapped relationship with each of said band segments extending in an opposite direction and with the room temperature vulcanizable silicone rubber being present on the upper and lower surfaces of said overlapping ends.

Claim 8

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by bonding the substantially flat surfaces of said band segments together with a room temperature vulcanizable silicone rubber in a manner sufficient to provide a flexible splice, through which said exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation, wherein the ends of said band segments are disposed in an overlapped relationship with each of said band segments extending in an opposite direction and with the room temperature vulcanizable silicone rubber being present on the upper and lower surfaces of said overlapping ends.

Claim 9

An improved process according to claim 6 wherein said multifilament band of acrylic fibrous material is selected from the group consisting essentially of an acrylonitrile homopolymer and acrylonitrile copolymer which contain at least 85 mole percent of acrylonitrile units and up to about 15 mole percent of one or more monovinyl units copolymerized therewith.

Claim 10

An improved process according to claim 6 wherein said multifilament band of an acrylic fibrous material is a flattened tow.

Claim 11

An improved process according to cliam 6 wherein said multifilament band has a width of about 1 to 36 inches.

Claim 12

An improved process according to cliam 6 wherein said multifilament band has a width of about 1 to 36 inches.

Claim 13

An improved process according to claim 6 wherein heat is applied to the overlapping band segments at temperatures of from about 50° to about 100° C for a period sufficient to achieve vulcanization of the surface of the room temperature vulcanizable silicone rubber.

Claim 14

An improved process according to claim 6 wherein pressure is applied to the overlapping band segments of from about 5 to about 10 psig during cure of the silicone rubber.

Claim 15

An improved process according to claim 6 wherein the extent of the overlap of the end portions of the band segments having the room temperature vulcanizable silicone rubber present thereon is from about 4 to about 9 times the width of a band segment.

Claim 16

The improved process of claim 6 wherein the room temperature vulcanizable silicone rubber is the reaction product of (A) a silanol chain-stopped polydiorganosiloxane of the recurring structural formula ##STR5## wherein R 1 and R 2 may be the same or different and represent organic radicals of not more than eight carbon atoms selected from the group consisting of hydrocarbyl, halohydrocarbyl, and cyano lower alkyl and n is an integer greater than 5, and (B) a polyfunctional organosilicone compound of the general formula R.sub.m SiX.sub.4-m wherein R is a member selected from the group consisting of hydrocarbyl, halohydrocarbyl and cyano lower alkyl raidcals, X is a reactive group capable of condensation with a silanol group of component A selected from the group consisting of hydroxyl, alkoxy, aryloxy, acyloxy, amino, ketoximo, aldoximo and amido, and m may vary from 1 to 3.

Claim 17

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by (a) providing a room temperature vulcanizable silicone rubber on the lower surface of the end of one of said substantially flat band segments, (b) providing a room temperature vulcanizable silicone rubber on the upper surface of the end of the previously treated band segment of step (a) in a manner sufficient to deposit said silicone rubber over an area, which is substantially coextensive with, and corresponds substantially to, the area covered by the silicone rubber present on said lower surface, (c) overlapping the end of a second substantially flat band segment with the previously treated end of the band segment of step (b) with each of said band segments extending in an opposite direction, (d) applying said room temperature vulcanizable silicone rubber to the upper surface of the end of said second band segment in a manner sufficient to deposit said silicone rubber over an area which is substantially coextensive with and corresponds to the area provided by the silicone rubber as provided in step (a), (e) subjecting said overlapping end portions of each band segment to pressure whereby the overlapping end of each band segment is wet and bonded together by said room temperature vulcanizable silicone rubber to form a flexible splice through which said exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation.

Claim 18

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by (a) providing a room temperature vulcanizable silicone rubber on the lower surface of the end of one of said substantially flat band segments, (b) providing a room temperature vulcanizable silicone rubber on the upper surface of the end of the previously treated band segment of step (a) in a manner sufficient to deposit said silicone rubber over an area, which is substantially coextensive with, and corresponds substantially to, the area covered by the silicone rubber present on said lower surface, (c) overlapping the end of a second substantially flat band segment with the previously treated end of the band segment of step (b) with each of said band segments extending in an opposite direction, (d) applying said room temperature vulcanizable silicone rubber to the upper surface of the end of said second band segment in a manner sufficient to deposit said silicone rubber over an area which is substantially coextensive with and corresponds to the area provided by the silicone rubber as provided in step (a), (e) subjecting said overlapping end portions of each band segment to pressure whereby the overlapping end of each band segment is wet and bonded together by said room temperature vulcanizable silicone rubber to form a flexible splice through which said exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation.

Claim 19

The process of claim 14 wherein the multifilament band of an acrylic fibrous material is selected from the group consisting of an acrylonitrile homopolymer and acrylonitrile copolymers which contain at least about 85 mole percent of acrylonitrile units and up to about 15 mole percent of one or more monovinyl units copolymerized therewith.

Claim 20

The process of claim 14 wherein the multifilament band of an acrylic fibrous material is a flattened tow.

Claim 21

The process of claim 14 wherein the multifilament band of an acrylic fibrous material has a width of about 1 to 36 inches.

Claim 22

The multifilament band of acrylic fibrous material according to claim 14 wherein the extent of the overlap of the terminal portions of the band segments having the silicone rubber present thereon is from about 4 to about 6 times the width of a band segment.

Claim 23

The process of claim 14 wherein the overlapping end portions of each band segment having the silicone rubber present thereon are heated to a temperature of about 75° to 100° C to hasten vulcanization of the surface of the silicone rubber.

Claim 24

The process of claim 14 wherein the pressure of bonding is about 5 to about 10 psig.

Claim 25

The process of claim 14 wherein the room temperature vulcanizable silicone rubber is a reaction product of (A) a silanol chain-stopped polydiorganosiloxane of the recurring structural formula ##STR6## wherein R 1 and R 2 may be the same or different and represent organic radicals of not more than eight carbon atoms selected from the group consisting of hydrocarbyl, halohydrocarbyl, and cyano lower alkyl and n is an integer greater than 5, and (B) a polyfunctional organosilicone compound of the general formula R.sub.m SiX.sub.4-m wherein R is a member selected from the group consisting of hydrocarbyl, halohydrocarbyl and cyano lower alkyl raidcals, X is a reactive group capable of condensation with a silanol group of component A selected from the group consisting of hydroxyl, alkoxy, aryloxy, acyloxy, amino, ketoximo, aldoximo and amido, and m may vary from 1 to 3.

Claim 26

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by (a) placing the end of one of said substantially flat band segments over a flat support, (b) applying a tension across said end of the band segment in a manner sufficient to suspend said end slightly above the support, (c) applying a room temperature vulcanizable silicone rubber to the lower surface of the end of said band segment between said surface and said support in a manner sufficient to avoid bonding of said silicone rubber to said support, (d) applying pressure to the surface of the end of said band segment having the silicone rubber present thereon to insure band wetting, (e) applying a room temperature vulcanizable silicone rubber to the upper surface of the end of the previously treated band segment in a manner sufficient to deposit said silicone rubber over an area which is substantially coextensive with, and corresponds to the surface covered by the silicone rubber present on said lower surface, (f) re-applying pressure to the surface of the end of the band segment having the silicone rubber present on its upper and lower surface to insure band wetting, (g) overlapping the end of a second substantially flat band segment with the previously treated end of the band segment of step (f) with each of said band segments extending in an opposite direction, (h) applying said room temperature vulcanizable silicone rubber to the upper surface of the second band segment in a manner sufficient to deposit said silicone rubber over an area which is substantially coextensive with, and corresponds to, the area covered by the silicone rubber as provided in step (c), (i) subjecting said overlapping ends of each band segment to pressure in a manner sufficient to compress the overlapping ends against said support whereby said overlapping ends are bonded together by said room temperature vulcanizable silicone rubber to form a flexible splice through which the exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation.

Claim 27

In a process for the thermal stabilization of a substantially flat multifilament band of an acrylic fibrous material wherein the ends of at least two discrete band segments each having an upper and lower surface are joined and continuously are passed in a successive manner in the direction of their length through a heated thermal stabilization zone, thereby inducing an exothermic cyclization reaction of pendant nitrile groups present thereon and wherein the original fibrous configuration of the same is maintained substantially intact for a residence time sufficient to render said band black in appearance, and non-burning when subjected to an ordinary match flame; the improvement comprising joining the ends of at least two of said band segments by (a) placing the end of one of said substantially flat band segments over a flat support, (b) applying a tension across said end of the band segment in a manner sufficient to suspend said end slightly above the support, (c) applying a room temperature vulcanizable silicone rubber to the lower surface of the end of said band segment between said surface and said support in a manner sufficient to avoid bonding of said silicone rubber to said support, (d) applying pressure to the surface of the end of said band segment having the silicone rubber present thereon to insure band wetting, (e) applying a room temperature vulcanizable silicone rubber to the upper surface of the end of the previously treated band segment in a manner sufficient to deposit said silicone rubber over an area which is substantially coextensive with, and corresponds to the surface covered by the silicone rubber present on said lower surface, (f) re-applying pressure to the surface of the end of the band segment having the silicone rubber present on its upper and lower surface to insure band wetting, (g) overlapping the end of a second substantially flat band segment with the previously treated end of the band segment of step (f) with each of said band segments extending in an opposite direction, (h) applying said room temperature vulcanizable silicone rubber to the upper surface of the second band segment in a manner sufficient to deposit said silicone rubber over an area which is substantially coextensive with, and corresponds to, the area covered by the silicone rubber as provided in step (c), (i) subjecting said overlapping ends of each band segment to pressure in a manner sufficient to compress the overlapping ends against said support whereby said overlapping ends are bonded together by said room temperature vulcanizable silicone rubber to form a flexible splice through which the exothermic heat of reaction is dissipated to an extent sufficient to avoid a deleterious effect on the original fibrous configuration which might otherwise result in the absence of such dissipation.

Claim 28

The process of claim 22 wherein the room temperature vulcanizable silicone rubber is a reaction product of (A) a silanol chain-stopped polydiorganosiloxane of the recurring structural formula ##STR7## wherein R 1 and R 2 may be the same or different and represent organic radicals of not more than eight carbon atoms selected from the group consisting of hydrocarbyl, halohydrocarbyl, and cyano lower alkyl and n is an integer greater than 5, and (B) a polyfunctional organosilicone compound of the general formula R.sub.m SiX.sub.4-m wherein R is a member selected from the group consisting of hydrocarbyl, halohydrocarbyl and cyano lower alkyl radicals, X is a reactive group capable of condensation with a silanol group of component A selected from the group consisting of hydroxyl, alkoxy, aryloxy, acyloxy, amino, ketoximo, aldoximo and amido, and m may vary from 1 to 3.