WEB-TREATMENT ROLLERS OF POLYURETHANE
United States Patent 3779051
This disclosure is directed to rollers for the treatment of textile webs and similar materials wherein the rolls come in contact with treating solutions applied to the webs. The roll consists of a cylindrical core having a shell of a material with an elastic surface. The surface comprises a polyurethane coating having a Shore A hardness of 86 to 96.
US Patent References:
Inking roll
Gartrell et al. - October 1961 - 3002866
Paper mill rolls
Martin et al. - April 1963 - 3087231
Squeeze-roll assembly
Osban - August 1963 - 3101563
Printer's roll comprising a polyurethane and method for producing same
Finelli - May 1964 - 3133340
Method for dyeing tubular knit material
Cohn et al. - November 1968 - 3412411
Inking roll
Gartrell et al. - October 1961 - 3002866
Paper mill rolls
Martin et al. - April 1963 - 3087231
Squeeze-roll assembly
Osban - August 1963 - 3101563
Printer's roll comprising a polyurethane and method for producing same
Finelli - May 1964 - 3133340
Method for dyeing tubular knit material
Cohn et al. - November 1968 - 3412411
Application Number:
05/329982
Publication Date:
12/18/1973
Filing Date:
02/06/1973
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
492/59, 100/176
International Classes:
D06B15/02; D06F45/00; D06B15/00; D06F45/22
Field of Search:
29/110,116R,116AD,129.5,132 68/244,248,258 100/155,169,176 8/147,148,151
US Patent References:
Primary Examiner:
Guest, Alfred R.
Parent Case Data:
This is a continuation, of application Ser. No. 35,362, filed May 7, 1970 now abandoned.
Claims:
What is claimed is
1. Cooperating rolls forming a nip resistant to materials such as dyes, synthetic finishings and latex impregnations, each of said rolls comprising a cylindrical roll body coated with polyurethane in the form of a dense uniform shell having a Shore A hardness of from 86 to 96 and fixed on said roll body, and the latter being formed by a controlled deflection roll, said rolls forming a nip width when under pressures not exceeding that conducive to the maximum removal of liquids from said webs while being elastic under said pressures to a degree uniformly squeezing said webs during feeding of web edges, folds, foreign bodies and the like.
2. Cooperating rolls forming a nip resistant to materials such as dyes, synthetic finishings and latex impregnations, each of said rolls comprising a cylindrical roll body coated with polyurethane in the form of a dense uniform shell having a Shore A hardness of about 94 and fixed on said roll body, and the latter being formed by a controlled deflection roll, said rolls forming a nip width when under pressures not exceeding that conducive to the maximum removal of liquids from said webs while being elastic under said pressures to a degree uniformly squeezing said webs during feeding of web edges, folds, foreign bodies and the like.
1. Cooperating rolls forming a nip resistant to materials such as dyes, synthetic finishings and latex impregnations, each of said rolls comprising a cylindrical roll body coated with polyurethane in the form of a dense uniform shell having a Shore A hardness of from 86 to 96 and fixed on said roll body, and the latter being formed by a controlled deflection roll, said rolls forming a nip width when under pressures not exceeding that conducive to the maximum removal of liquids from said webs while being elastic under said pressures to a degree uniformly squeezing said webs during feeding of web edges, folds, foreign bodies and the like.
2. Cooperating rolls forming a nip resistant to materials such as dyes, synthetic finishings and latex impregnations, each of said rolls comprising a cylindrical roll body coated with polyurethane in the form of a dense uniform shell having a Shore A hardness of about 94 and fixed on said roll body, and the latter being formed by a controlled deflection roll, said rolls forming a nip width when under pressures not exceeding that conducive to the maximum removal of liquids from said webs while being elastic under said pressures to a degree uniformly squeezing said webs during feeding of web edges, folds, foreign bodies and the like.
Description:
BACKGROUND OF THE INVENTION
The rolls conventionally used for the treatment and squeezing of webs comprise discs of nonwoven fabrics pressed together and fitted onto a core or shaft. The nonwoven fabrics contain cellulose fibers or natural fibers and a portion of synthetic fibers, preferably a polyamide. The nonwoven fabric discs are saturated and made firm by a rubber-like solution. The high squeezing capacity of rolls built of such discs is due to a great extent to the nonwoven fibers which are at the outer circumference of the roll and which have the characteristic of a brush with bristles which have been pressed together very tightly. This characteristic of the roll surface results in a high elasticity and a relatively good deformation capability of the surface. When using these rolls for squeezing textiles, the elastic surface of the rolls penetrates the recesses built up by warp and weft and removes a maximum volume of water.
The above type of surface characteristic is, however, not suitable for processes other than squeezing textile webs. For example, the impregnation of synthetic resins into a web cannot be performed with these rolls in a satisfactory manner. During such impregnation, the resin works itself into the fine pores of the roll surface with the consequence that the rolls quickly become covered with a thick resin coating. Similarly, in the process of impregnating textile webs with a rubber-like substance the rolls become covered with a rubber coating which clings to the surface of the rolls and makes them unsatisfactory for continued use. The above-described rolls also create difficulties when applying a dye to a textile surface because the rolls do not provide a sufficiently uniform application of the dye and result in considerable difficulties in cleaning the roll surface. Additionally, the rolls are not sufficiently elastic and during prolonged operation the edges of the webs mark the rolls. Dyeing tests must be performed with newly refaced rolls of this kind due to different densities obtained during pressing of the non-woven fabric onto the rolls.
A rubber cover for the roll is often not satisfactory because it lacks the required hardness and elasticity. Rubber rolls, depending on the quality of the material to be treated, generally produce results which are about 15 to 20 percent worse than that of the fiber rolls.
An important requirement in the technique of dyeing textiles is to apply a minimum amount of liquid. It has been determined that the so-called migration of dye is insignificant at a certain minimum liquid level. This liquid minimum is near the swelling capacity of the fibers. It is therefore necessary when dyeing to closely and uniformly control the pressure applied to treated webs.
An object of this invention is to provide a roll which avoids the aforementioned disadvantages; which provides a substantial squeezing effect upon a web in order to prevent or diminish the migration of the dye particles; and wherein dyeing is accomplished with the minimum application of liquid.
A further object of this invention is to provide a roll which is suitable for the treatment of textile webs to which dyes, synthetic finishings, and latex impregnations are applied.
Yet another object of this invention is to provide the roll having sufficient elasticity and hardness for the above noted uses.
These and other objects are obtained with the roll hereinafter described in greater detail.
THE INVENTION
This invention is directed to a roll having a shell with a surface of dense polyurethane of a Shore A hardness of 86 to 96. The roll according to the present invention is of sufficient hardness to prevent the formation of too wide a nip between companion pressing rolls since too wide a nip would not be conducive to the required maximum removal of liquid. The roll surface is highly elastic and therefore completely smooths undesired deformation which occurs, for example, during feeding of web edges, folds or foreign bodies. In addition, the roll has the ability to maintain its shape and stability; this is of utmost importance since during dyeing the smallest deformation of the cylinder roll results in visual imperfections. The roll of the present invention is also resistant against dyes and other impregnating materials. The roll shell has a smooth surface which prevents adhesion of dyes and finishing materials, and makes the removal of these foreign bodies easier.
Preferably, the shell for the rolls of the present invention has a Shore A hardness of about 94 for the treatment of textile webs with materials like dyes, synthetic finishings, latex impregnations, and other applications of such materials to webs. The polyurethane shell is preferably applied by coating the core of the roll, in accordance with conventional coating techniques. In order to accomodate the very wide rolls used in the textile industry, often having a length of about 1.6 meters, it is desirable to use a controlled deflection roll in the present invention. The detailed mechanism of a controlled deflection roll is set forth in U.S. Pat. No. 2,908,964. This type of construction prevents the deflections and uneven operations which would otherwise occur with large rolls.
The drawings show a preferred embodiment of this invention in which the polyurethane shell is used in connection with a controlled deflection roll such as is described in U.S. Pat. No. 2,908,964.
FIG. 1 shows a pair of cooperating rolls, each of the same construction, with a partial cross sectional cutaway of the upper roll which shows the interior thereof.
FIG. 2 shows a side view of the rolls including a partial longitudinally cross sectioned view along lines 2--2 of FIG. 1.
Each of the rolls generally designated as 1 and 2 comprises a shell 5 which consists of polyurethane fixedly mounted on a controlled deflection roll 3 of circular cross section. Polyurethane shell 5 has a Shore A hardness of 86 to 96, for example, a Shore A hardness of 94 has been found to be very effective. Polyurethane shell 5 may be manufactured by coating the shell 6 of the controlled deflection roll 3 with an adhesive and a liquid polyurethane. The particular adhesive and the polyurethane used to obtain the desired hardness are chosen from commercial materials well known to those skilled in the art. The controlled deflection roll upon which the polyurethane shell 5 is mounted in this embodiment comprises the hollow shell 6 which is mounted to rotate about the stationary shaft 7. Bearings 11 are provided to position the shell 6 with respect to the stationary shaft 7. The shaft 7 being of such a size as to define within the inner surface of the shell 6 an intermediate space 9. The longitudinal seals 8 divide the space into two compartments, one on the pressure applying side of the roll and the other on the opposite side of the roll, 12 and 13 respectively. The compartment 12 on the nip or pressure applying side of the roll is sealed in the axial direction at each end thereof, so as to form a longitudinal pressure chamber on the working side of the roll extending the length thereof which can be filled by a fluid, said end seals are adjacent bearings 11. The ends 4 of the shaft 7 extend beyond the ends of the shell 6 and can be mounted in frames not shown. In operation the deflection of the roll can be controlled through the adjustment of the fluid pressure inside the compartment 12. The fluid pressure may be applied through the bore 10. Further details of the structure in operation of a controlled deflection roll such as herein described are set forth in U.S. Pat. No. 2,908,964.
The invention is not limited to the embodiment shown. For example, the roll used need not be a controlled deflection roll.
The novel rolls of this invention provide for the improved processing of textile webs which are treated thereby. The method of this invention comprises passing a textile web through rolls having a polyurethane shell. The textile web is uniformly squeezed and maximum effectiveness of the applied material, i.e., dye, finish, latex, etc., is obtained.
This invention has been described in terms of specific embodiments set forth in detail. Alternative embodiments will be apparent to those skilled in the art in view of this disclosure, and accordingly such modifications are to be contemplated within the spirit of the invention as disclosed and claimed herein.
The rolls conventionally used for the treatment and squeezing of webs comprise discs of nonwoven fabrics pressed together and fitted onto a core or shaft. The nonwoven fabrics contain cellulose fibers or natural fibers and a portion of synthetic fibers, preferably a polyamide. The nonwoven fabric discs are saturated and made firm by a rubber-like solution. The high squeezing capacity of rolls built of such discs is due to a great extent to the nonwoven fibers which are at the outer circumference of the roll and which have the characteristic of a brush with bristles which have been pressed together very tightly. This characteristic of the roll surface results in a high elasticity and a relatively good deformation capability of the surface. When using these rolls for squeezing textiles, the elastic surface of the rolls penetrates the recesses built up by warp and weft and removes a maximum volume of water.
The above type of surface characteristic is, however, not suitable for processes other than squeezing textile webs. For example, the impregnation of synthetic resins into a web cannot be performed with these rolls in a satisfactory manner. During such impregnation, the resin works itself into the fine pores of the roll surface with the consequence that the rolls quickly become covered with a thick resin coating. Similarly, in the process of impregnating textile webs with a rubber-like substance the rolls become covered with a rubber coating which clings to the surface of the rolls and makes them unsatisfactory for continued use. The above-described rolls also create difficulties when applying a dye to a textile surface because the rolls do not provide a sufficiently uniform application of the dye and result in considerable difficulties in cleaning the roll surface. Additionally, the rolls are not sufficiently elastic and during prolonged operation the edges of the webs mark the rolls. Dyeing tests must be performed with newly refaced rolls of this kind due to different densities obtained during pressing of the non-woven fabric onto the rolls.
A rubber cover for the roll is often not satisfactory because it lacks the required hardness and elasticity. Rubber rolls, depending on the quality of the material to be treated, generally produce results which are about 15 to 20 percent worse than that of the fiber rolls.
An important requirement in the technique of dyeing textiles is to apply a minimum amount of liquid. It has been determined that the so-called migration of dye is insignificant at a certain minimum liquid level. This liquid minimum is near the swelling capacity of the fibers. It is therefore necessary when dyeing to closely and uniformly control the pressure applied to treated webs.
An object of this invention is to provide a roll which avoids the aforementioned disadvantages; which provides a substantial squeezing effect upon a web in order to prevent or diminish the migration of the dye particles; and wherein dyeing is accomplished with the minimum application of liquid.
A further object of this invention is to provide a roll which is suitable for the treatment of textile webs to which dyes, synthetic finishings, and latex impregnations are applied.
Yet another object of this invention is to provide the roll having sufficient elasticity and hardness for the above noted uses.
These and other objects are obtained with the roll hereinafter described in greater detail.
THE INVENTION
This invention is directed to a roll having a shell with a surface of dense polyurethane of a Shore A hardness of 86 to 96. The roll according to the present invention is of sufficient hardness to prevent the formation of too wide a nip between companion pressing rolls since too wide a nip would not be conducive to the required maximum removal of liquid. The roll surface is highly elastic and therefore completely smooths undesired deformation which occurs, for example, during feeding of web edges, folds or foreign bodies. In addition, the roll has the ability to maintain its shape and stability; this is of utmost importance since during dyeing the smallest deformation of the cylinder roll results in visual imperfections. The roll of the present invention is also resistant against dyes and other impregnating materials. The roll shell has a smooth surface which prevents adhesion of dyes and finishing materials, and makes the removal of these foreign bodies easier.
Preferably, the shell for the rolls of the present invention has a Shore A hardness of about 94 for the treatment of textile webs with materials like dyes, synthetic finishings, latex impregnations, and other applications of such materials to webs. The polyurethane shell is preferably applied by coating the core of the roll, in accordance with conventional coating techniques. In order to accomodate the very wide rolls used in the textile industry, often having a length of about 1.6 meters, it is desirable to use a controlled deflection roll in the present invention. The detailed mechanism of a controlled deflection roll is set forth in U.S. Pat. No. 2,908,964. This type of construction prevents the deflections and uneven operations which would otherwise occur with large rolls.
The drawings show a preferred embodiment of this invention in which the polyurethane shell is used in connection with a controlled deflection roll such as is described in U.S. Pat. No. 2,908,964.
FIG. 1 shows a pair of cooperating rolls, each of the same construction, with a partial cross sectional cutaway of the upper roll which shows the interior thereof.
FIG. 2 shows a side view of the rolls including a partial longitudinally cross sectioned view along lines 2--2 of FIG. 1.
Each of the rolls generally designated as 1 and 2 comprises a shell 5 which consists of polyurethane fixedly mounted on a controlled deflection roll 3 of circular cross section. Polyurethane shell 5 has a Shore A hardness of 86 to 96, for example, a Shore A hardness of 94 has been found to be very effective. Polyurethane shell 5 may be manufactured by coating the shell 6 of the controlled deflection roll 3 with an adhesive and a liquid polyurethane. The particular adhesive and the polyurethane used to obtain the desired hardness are chosen from commercial materials well known to those skilled in the art. The controlled deflection roll upon which the polyurethane shell 5 is mounted in this embodiment comprises the hollow shell 6 which is mounted to rotate about the stationary shaft 7. Bearings 11 are provided to position the shell 6 with respect to the stationary shaft 7. The shaft 7 being of such a size as to define within the inner surface of the shell 6 an intermediate space 9. The longitudinal seals 8 divide the space into two compartments, one on the pressure applying side of the roll and the other on the opposite side of the roll, 12 and 13 respectively. The compartment 12 on the nip or pressure applying side of the roll is sealed in the axial direction at each end thereof, so as to form a longitudinal pressure chamber on the working side of the roll extending the length thereof which can be filled by a fluid, said end seals are adjacent bearings 11. The ends 4 of the shaft 7 extend beyond the ends of the shell 6 and can be mounted in frames not shown. In operation the deflection of the roll can be controlled through the adjustment of the fluid pressure inside the compartment 12. The fluid pressure may be applied through the bore 10. Further details of the structure in operation of a controlled deflection roll such as herein described are set forth in U.S. Pat. No. 2,908,964.
The invention is not limited to the embodiment shown. For example, the roll used need not be a controlled deflection roll.
The novel rolls of this invention provide for the improved processing of textile webs which are treated thereby. The method of this invention comprises passing a textile web through rolls having a polyurethane shell. The textile web is uniformly squeezed and maximum effectiveness of the applied material, i.e., dye, finish, latex, etc., is obtained.
This invention has been described in terms of specific embodiments set forth in detail. Alternative embodiments will be apparent to those skilled in the art in view of this disclosure, and accordingly such modifications are to be contemplated within the spirit of the invention as disclosed and claimed herein.