DE2019815A1 - Film structure useful in making crimped multi-component yarns and fibers, and the method and apparatus for making the same - Google Patents

Description

DR. ING. F. WUKSTHOFF 0 Π 1 QQ Λ C ₈ MUNICH OO * DIPL-INCG-PtTLS ■ ^Μ '° ^' ° SCnWEIQERSTHASSB S DU.E.v.PECIIMANN «LjeroM 88 00 01 PR. ING. D. BEHRENS ^ «» ^ »λ .., ^ ,, PATENTANWiLTE ΡΠΟΤΚΟΤΡΑΤΕΝΤ

la-37718

description to the patent application

SHElI INTERNATIONAL RESEARCH MAATSCHAPPIJ N.Yi

Carel van Bylandtlaar »30, The Hague Netherlands

"concerning /

For the production of crimped multifunctional composite yarns and fibers usable plastic structure and method and device for its production. · ·

Yarns and fibers made from several, especially two, components are generally manufactured using two basic methods, both based on the extrusion of molten thermoplastics Based on polymers. According to one of these processes, the polymers are simultaneously pressed out through a spinneret. The other method uses; each individual poly- · | merisat pressed through a slit to form a film and you. receives then the films are adhered to by a film laminate, which is then stretched and finely shredded (fibrillation) is converted into thread-like structures with latent or current crimp,

According to the invention, on the other hand, it is used to produce crinkled Multi-component yarns and fibers a structure consisting of a single-layer film with firmly adhered thereto, essentially parallel ribs or ridges.

The profiled film structure according to the invention consists of a film made of thermoplastic material, which in the -vorstreckten zu-

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can be fiberized (fibrillated) lengthwise; this film is on one or both outer sides with closely spaced and substantially parallel ribs or Provided with ridges made of thermoplastic material, which differs from the material contained in the film, exist and have a substantially constant cross-section over their entire length. The invention also includes a method for producing such a structure, which is characterized in that one melts from a thermoplastic material that can be fibrillated in the stretched state through a linear or annular slot extruded a film through holes adjoining or closely spaced around the slot, another thermoplastic material is extruded in the molten state into parallel ridges or ridges which adhere to the film and are made of a material different from the material contained in the film.

The profiled structure according to the invention must be clearly distinguished the grounding of a profiled single-layer film; also it must be distinguished from a laminated film, i. a film of two or more layers bonded together.

One of the advantages of the structure according to the invention particularly well as a starting material for the production of yarns and What makes fibers suitable consists in the fact that the ribs are made of a material that is less easily fiberizable (fibrillatable) can be used. Another advantage is that in the structure according to the invention, the gap zones largely are predetermined so that the fibrillation process can be better controlled and a fibrillate of better uniformity and very high strength.

The production of the structure takes place continuously and if so

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Continuous yarns are produced ^ the structure is simply drawn and fibrillated. For the purpose of making Staple fibers are cut before the drawn product Fibrillation to the desired staple length. ·,

The structure can be flat or tubular and of any desired shape Be broad, something only of shape and size depends on the slot used to make it. As well as the flat as well as the tubular structures can Length to be cut to a correspondingly smaller width. The structures according to the invention also include from the outside tubular structures covered with ribs which, after extrusion, have passed through nip rollers and thereby are laid flat.

The thickness of the film portion is according to the invention -.,. ". Forms usually between 0.01 and 3 mm, preferably between Ο., ϋ? and 1 mm. The same size ranges apply for the height of the ribs.

AIg starting material for the film part of the image can be a Any thermoplastic material that can be fibrillated can be used, i.e. a material that is in the form of a BaIm adopts a molecular orientation by stretching,, ^ e.g. the homo- and copolymers of vinyl chloride, vinylidene chloride, Vinyl acetate or acrylonitrile as well as polyester and ■■ polyamides ·. Preferred among these are homopolymers and copolymers of j'ithy 1 er; - and especially of propylene.

The polymer raw materials for the ribs are only used to make the requirement that the resulting "extrusion formed ribs consist of a material that differs from the one that represents the film part of the structure, differs. The difference can be that

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the stress-strain ratio "at any temperature. the material for the film and that for the ribs is different when both are in the same condition as they are in the structure in a stretched or undrawn condition are present. This requirement of a difference in the stress-strain behavior excludes structures in which the film portion and the ribs have an identical composition and properties. Because of Due to the differences in the stress-strain behavior, internal stresses occur when the structure is stretched lead to the fact that the length of the film portion and that of the ribs are different or that this difference is at the latest developed after the heat treatment of the stretched structure. These internal tensions usually do not lead to one significant change in shape as long as the structure is not frayed (fibrillated).

The above requirement does not mean that the polymeric The starting materials have to be different because the difference in the stress-strain behavior to be observed in the end between the parts of the structure can also be produced in other ways, about which we have yet to talk will. In practice, the polymeric starting material for the ribs can be different from the film-forming material not. When using different polymers, it is important that the extruded ribs match the extruded film be firmly attached that 'maintain the connection while stretching remain. Such a strong 'liability is usually too observe between macromolecular thermoplastics that have a chemical relationship, e.g. nylon G with Nylon 66; Polyethyl acrylate with polymethyl methacrylate; Polyvinyl chloride with polyvinylidene chloride; Polypropylene with polyethylene or polypropylene with random or block copolymers of propylene and ethylene.

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Very good adhesion between the ribs and the film base can be achieved if one works for both parts of the structure completely identical macromoleculars are used. In this case, the above-mentioned requirement can thereby be met be that one in the two parts of the structure incorporates various substances, e.g. others. Polymers, killers, Pigments and / or plasticizers. Optionally, the film and ribs can be of different colors, which is achieved, for example, by using different dyes or substances which improve the colorability are incorporated.

The material for the film can be different from that for the ribs also differ in terms of porosity; for example, the ™ one part compact and the other a foam or both parts of the structure can consist of foam, the however, different densities, i.e. different total pore volumes per unit of volume.

Very good adhesion between the parts can also be achieved if the starting polymers are chemically identical, however, in the mean molecular weight, in the molecular weight distribution, the stereoconfiguration, the crystallinity and / or the orientation differ. ■

A structure of this type can be prepared by \ dividing the flow of molten thermoplastic polymer into different branches and this at different temperature and / or over a different time period and / or ER- at various shear rate hitzt so that the average molecular weights decrease in the branches to a different degree, whereupon the material in one of the branches is extruded through the slot and that in the other branch or branches through the bores located next to or around the slot. The difference in the middle MoIe- - - ■■ '■. - ■■■ '- 6 -

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Cell weight can also be at the same temperatures and same Heating times of the individual branches are obtained when the latter have different concentrations of the molecular weight contain stabilizing agents or, if only in one of the branches, an agent for stabilizing the molecular weight is included. Stabilizers in the case of polyolefins are, for example, phenols, in particular polyhydric Phenols such as biphenols and triphenols, organic sulfides such as dilauryl thiodipropionate, organic phosphites, such as tri- (nonylphenyl) phosphite, and amines. They are usually used in concentrations of 0.05 to 2% by weight. A difference can also be caused by using substances that influence the crystallization, e.g. nucleating agents. With polypropylene, for example, it is possible to ensure that very small spherulites can be obtained by adding certain carboxylic acids or their anhydrides or salts. These nucleating agents e.g. diphenylacetic acid and o- and p-butylbenzoic acid v / earth. gev / usually in amounts from 0.05 to 5 »in particular from 0.1 to · 1.5% by weight used.

The additives mentioned above (fillers, pigments, dyes, plasticizers, agents that promote flowability, substances to regulate the crystallization and stabilizers) can of course be used in the same or different concentrations can also be used if there is only chemical identity between the thermoplastics in the individual parts of the structure or no identity at all.

The invention also relates to a device for production of the profiled film structures mentioned, consisting of an extrusion spinning head which is provided with a linear or annular slot and with holes that adjoin this slot or in its immediate vicinity Neighborhood, with the slot having a

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first line is in communication with a vessel and the Holes are connected by a second conduit to a vessel separate from the first. · The term "vessel" means here a heated cylinder, an extruder, a gear- ' pump and corresponding auxiliary equipment.

The slot can be any in the device according to the invention. have suitable length. Usually the length of straight slots and the circumference of annular slots is 10 to 100 cm. The width (thickness) of the slot depends of course on the desired thickness of the structure and is usually within the ranges mentioned above. Both the lenticular and the annular slots and also the. Holes can be of any shape, but straight or circular slots are preferred. Slots which cooperate with holes arranged on one side can advantageously be provided with constrictions on the other side, which is opposite the holes. In. In this context, reference is made to the drawing, in many of which FIGS. 1, 3, 5 and 7 represent schematic plan views of suitable spinning heads. _f

The device of the invention further includes all \ devices usually used for the extrusion of thermoplastic resins, such as means for melting of the polymeric education

, for conveying the melt through the lines, to cool the extrudate and to transport it to its place of processing. The processing can consist of, among other things, slitting, heating, drawing, tempering, fibrillation and in cutting to the required staple fiber length *

The structures according to the invention can also be produced in such a way that that a film is first extruded in the usual way, on the surface of which one then comes out of a separate extrusion device or another suitable facility

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Number of thin threads applies. Another possibility for producing the structures according to the invention is that one first a number of narrow strips or threads that run parallel and close to each other and then attach these elements to a film by for example extruded a film over it. However, are the two last-mentioned methods are more cumbersome and the structures are therefore preferably made using one single nozzle as described above.

The method according to the invention proves to be particularly advantageous in the production of multi-component yarns and fibers, the profiled structure, optionally slit lengthways to a suitable width, being stretched, the stretched structure fibrillates and possibly heats the fibrillate to develop a curl therein. In some cases where the structure is in threads is transferred., the fibrillation already takes place during the drawing, but usually the separate Fibrillation stage switched on only after stretching. Any suitable method can be used for fibrillation, e.g. twisting, rubbing, cutting, brushing or the stretched structure becomes a gas flow or a exposed to rapid flow of solid particles. A preferred P fibrillation method is that you over the structure pulls a rotating cylinder studded with needles, which moves in the same direction but faster than the structure, emotional.

In some cases, the multi-component threads obtained by fibrillation already have a sufficient amount for processing Ripple on. It has usually proven advantageous to use the fibrillate or those produced from it Subjecting objects or fabrics to further treatment in which the curl is developed, which, for example,

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can be done wisely by heating. In most cases there is brief exposure to hot air or steam gives excellent results.

The multi-component yarns and fibers produced in this way have a strong, loosening ripple. they are As a result, it can be used for a wide range of purposes »e.g. as ■ filling material, for example for cushions and mattresses and as a heat-insulating or sound-absorbing material. First and foremost however, the yarns and fibers of the present invention find utility in the textile field, e.g., woven, knitted and nonwoven fabrics Were.

The examples serve to explain the invention in more detail. example 1

It was used to produce a yarn or staple fiber a spinning head is used as shown schematically in FIG. 1 in Top view is shown. The spinner head had a linear slot with a length of 50 cm and a width of 0.5 mm

. from ■ '· - ■ - ■ -. "

on. At a distance of 0.3 mm / the edge of the slot a series of right-angled holes with a length and width of 0.5 mm each was arranged. With the aid of a single-screw extruder, a polypropylene homopolymer was ^{extruded through the slot at 260 °} C. at a speed of 1 m / min to form a film. The homopolymer used had an approximate melting point (MP) of 168 ⁰ C, a melt index (MI), expressed in g / 10 min of. 8.3 and a molecular weight distribution index (MIQ) of 5 *) Using a second extruder, a polypropylene hormone aerosol with the same MP, an MI of 1.3 and an MIQ of 11 was simultaneously through the holes extruded. The threads thus obtained adhered firmly to the film. The finned structure was then cooled by moving it at a speed

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of 10 m / min through, a water bath was passed; one received a structure ^, which is shown schematically in Fig. 2 in cross section is.

Das'Gebilde was made with razor blades in strips of 5 cm Wide slit and stretched at 135 ° C in a ratio of 1: 9, whereupon using the above-described, cylinder equipped with needles was fibrillated »Man- · · held fine yarns with good crimp. The yarns and the

'of

Staple fibers obtained by chopping / fibrillates turned out to be very loose the curl is somewhat increased.

*) Calculated using the equation

10 WED _{5 0}

log MIQ = 0.25 __111 - 0.225

^MI 2.16

'represent MIc wherein q and M ₂ ^ melt indices were determined at 2 John ⁰ C according to ASTM D 1238 using a piston load of 5 or 2.16 was .angewandt kg. For polypropylene, an MIQ value of 3 to 6 indicates a narrow molecular weight distribution and an MIQ value of 8 to 15 indicates a broad molecular weight distribution.

Example 2

According to Example 1, a structure provided with ribs was produced but in this case the material with the low MI through the slot and the material with the MI of 8.3 was extruded through the holes.

The fibrillation of the structure thus formed was satisfactory, although somewhat less easily than was obtained in Example 14

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a coarser yarn that-less puckered and. less loose was than that according to Example 1. The same also applies to a comparison of the fibrillates after heat treatment.

Example 3

To produce a film structure according to the invention, a device was used in which the spinning head corresponds to the plan view shown in FIG. 3; the 0.4 ram wide slot covered a circle with a diameter of 12 cm. It was surrounded at a distance of 0.2 mm by square holes 0.4 mm on a side, spaced 0.4 ram apart. By the circular slot ein.Polypropylenhomopolymerisat was compressed with a MP of 168 ⁰ C, an MI of 8.3 and a MIQ of 5 with the help of a conventional extruder. Using a second extruder, a copolymer of ethylene and propylene was pressed through the holes, which had a HP of 148 ° C, an MI of 8; and had an MIQ of 7. The extrusion speed for both the film and the tilt was about 1 m / min. During the extrusion of the tubular film, that was. ^The extrudate is cooled with air from the outside and from a device arranged in a ring in order to improve the stretchability. A blow-up ratio of 1: 1.2 and a suction ratio of 9 mm / sec were used, for which purpose rollers were used in the Z "lay-flat technique".

The structure thus produced, the cross-section of which is shown schematically in Fir ;. 4, it was stretched at 135 ° C. with a stretching ratio of 1:10 and then fibrillated over a cylinder provided with ICacels. First, the yarn thus obtained showed only a weak crimp which could be, however, developed by heat treatment at 135 ⁰ C to an excellent crimp.

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Example 4

To produce a film structure according to the invention, a device is used, the spinning head is shown schematically in Fig. 5; it contained a profiled one linear slot 50 cm long. The slot was on that 0.21 mm wide at the narrow spots and 0.5 mm wide at the wide spots, and the rectangular protrusions were in spaces of 0.5 mm arranged. At a distance of 0.2 mm from the Square holes with a side length of 0.5 mm were arranged on the straight side of the slot. A polypropylene homopolymer with an MP of 169 ° C, an MI of 9, and an MIQ of. 4.5 was extruded through the profiled slot while a polypropylene homopolymer with an MI of 1.2 and an MIQ of 11 was extruded through the holes. By both A draw ratio of 1:11 was used for extrusions.

After cooling the combined extrudates in water, one obtained a structure, the cross-section of which is shown schematically in FIG. 6, but with one during the extrusion certain rounding of the edges took place.

The structure was slit into strips of 5 cm and stretched at 135 ° C in a ratio of 1: 9. The yarns obtained after fibrillation were good Ripple and were very loose. By cutting the yarns, staple fibers of excellent quality were obtained, which could easily be used for a wide variety of purposes in the textile field.

Example 5

^{A polypropylene homopolymer with an MP of 168 °} C., an MI of 8.3 and an MIQ of 5 was made on a device, the spinning head of which is shown schematically in FIG

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through the linear slot, which is 30 cm long and had a width of 0.4 mm., extruded. Simultaneously was through the illustrated semicircular openings that had a radius of 0.3 mm and intervals of 0.5 mm spaced 0.3 mm from the slot Polypropylene homopolymer with the same MP, an MI of 1.3 and an MIQ of 11.

The structure obtained in working up according to Example 1 had a cross-section according to FIG. 8 and resulted in fibrillation ren a bicomponent yarn with good, but slightly less Crimp than the yarn of Example 1.

B e is ρ i el 6_ '

A film structure was produced under the same conditions as in Example 1, except that the distance between Slot and square holes was 1 cm and cooling ·. was effected with the help of a cooling roller, the surface of which at a distance of 3 cm from the surface of the spinner head and which rotated in the direction of the holes.

The by stretching at 140 ⁰ C in a ratio of 1: 9 and

Fibrillation of the yarns obtained corresponded to

the crimp and the looseness of the products \ %

according to example 1, i.e. they were of the best quality. *

PATENT CLAIMS.

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Claims (6)

■ 1A-37 718 Uc η ε 1) Profiled film structure, consisting of a film thermoplastic material that can be fibrillated in the stretched state and on one or both surfaces with the length is occupied at a closely spaced substantially parallel ribs that extend from a Fij_mmaterial are made of thermoplastic material and their cross-section essentially over their whole Length is constant. 2) j Method for producing the profiled film structure according to claim 1, characterized in that a melt of fibrillatable in the stretched state thermoplastic material extruded through a linear or annular slot into a film and that one separately extruded a melt of thermoplastic material through openings adjoining the slot or are arranged at a small distance from it, such that substantially parallel ribs firmly adhering to the film which are made of a material different from the material of the film. 3) Method according to claim 2, characterized in that one is used as the film-forming material a homo- or copolymer of ethylene or propylene is used. 4-) Device for performing the method according to claim 1, characterized by an extrusion spinning head with a linear or annular slot and with openings adjoining the slot or are arranged at a small distance from it, the slot "i Connects to a vessel via a first line - 15 - 009845/1814 -15- 1A-37 718 and the opening via a second conduit leading from the first separated - '. is arranged, are also in connection with a vessel. " 5) Device according to claim 4, characterized in that g e k e η η -. ζ ei c h η e t that both lines are in the same vessel arise from. 6) Use of the profiled film according to claim 1 for Production of multi-component yarns and fibers, thereby characterized in that one has the profiled structure according to claim 1, optionally after cutting in the longitudinal direction into strips of suitable width, stretched and fibrillated, after which it is optionally heated to its Develop ripple. 009845/1814 Blank page