DE1494721A1 - Light transmitting thread - Google Patents

Description

E. I. DU PONT DB NENOURS AND COMPANY 10th and Market Streets, Wilmington, Delaware 19896, V.St.A.

Lloht Transferring thread

The invention relates to coated threads that light over Able to transfer considerable lengths of thread, for the insertion in flexible, pliable, lloht-transferring thread bundles.

Flexible, light and image-transmitting thread bundles have hitherto been made up of glass thread. Solohe 01as thread bundles are heavy, fragile, not resistant to high-energy radiation consistent and costly. The two-way, light-transmitting Making threads from artificial polymers, 1st has already been recognized. In those cases in which such threads have been reported, however, they have light Only to be transmitted over short Streoken.

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New subjects

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The invention relates to a light-transmitting thread made of a core of 0.0015 to 0.64 mm diameter, to which a dumbbell of 0.0013 to 0.13 mm thickness is applied, which is characterized in that the core resin is an alkyl methaorylate polymer with a content of at least 70 % of alkyl methacrylate, wherein the alkyl group contains 1 to 6 carbon atoms, and the shell resin is a polymer of a telomer of the structural formula

X (CP ₂ ) _n (CH2) _m OC.C - CH ₂

OY

1st, in which X is H, F or Cl, η is an integer from 2 to 10, m is an integer from 1 to 6 and Y is H or CH.

The present invention makes combinations of artificial, polymeric materials available, including optical and physical Have properties that are necessary for the production of sheath-core threads that are both flexible and flexible as well as being able to transmit light effectively. This is described in more detail below with reference to the drawing in which Fig. 1 is a perspective view of a thread according to the invention,

Fig. 2 shows a spinning head for a sheath-core thread and the the receiving device forming the thread bundle, FIG. 3 shows a bath for covering the thread and one the thread bundle forming receiving device, FIG. 4 shows a section through the receiving device forming the thread bundle according to line 4-4 of FIG. 2 and FIG. 5 shows the finished, light-transferring thread bundle.

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Oil structure of the lloht-transferring thread according to the invention is in Flg. 1 on the basis of the thread 1 with a permeable Resin core and a durohe hollow jacket J5 shown. Of the Thread naoh Flg. 1 can be obtained in two alternative ways. After the first method a spinneret 4 is used for Sheath-core threads, as detailed in U.S. Patent 2,936 described / attached to two polymer extrusions and pressed a sheath-core thread. The thread 1 is on the 2- to lOOfaohe refined and on the one that forms the bundle of threads Take-up reel 10 added. Zm operation of the spinneret is the core forming resin 5 from an extruder into the central dura tube 6 and the cladding material 16 around the core fed and pressed out at the same time as the core material to form the sheath-core thread. Good for sio production A leveling mechanism can be used to ensure transmission 11 insert «to slohern an equal winding of the thread. With the other method, the core of the thread becomes duroh a bath 12 out, which contains a solution of the sheath-forming material 13 »and on which the thread bundle forming Coil 10 ', which is designed in an identical manner to that of the coil 10 1st «recorded. In the state filled with sheath-core threads, the bobbin 10 has the structure shown in FIG. Well the filling with threads 1, the threads are attached to one another on a segment of the thread bundle. You cut the bundle then at .der point at which the threads have been attached to each other, and surrounds it with a suitable sheath, such as an Oummi- or Plastsohlauoh 14 or a braided one Drahtsohlauoh, whereupon the lloht-transferring thread bundle 15 is ready is present.

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For effective light transmission it is necessary that the loss of intensity of the "welsaen ¹ * light" does not exceed 50 £ /? 0 cm in length. In the test, a conventional tungsten filament incandescent lamp with a color temperature of 2300 ° K is used as the standard source for "white" light To determine the light transmission (T), the light is focused on one end of a group of threads from 1.2 to 2.4 mm in length and the intensity of the transferred solder is measured by means of a phototube the intensity of the transmitted light is determined again. By repeating this procedure of short trimming of the threads and measuring the intensity of the transmitted light for each syllable, a graphical representation of the logarithm of the intensity against the length can be obtained, with the inclination of the curve obtained being equal to the absorption · Coefficient (α) from which the transmission (T) can be calculated ^{as T »100e aX, in which} e is the base of the natural logarithm and X is the streoke (30 om).

The light-transmitting core thread is preferably made of a. Made of plastic, the light transmission of which is more than 90 % / JO cm. For general purposes, the aoryl resins are the preferred thread core material because of their high optical transparency. With appropriate care, core-sheath threads can be produced using cores made of acrylic resins, such as polymethyl methaorylate, the transmission oute of which is that of light-transmitting threads from Olae Is superior.

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The acrylic resins used for the production of the threads according to the invention must have a high degree of transparency and be sufficiently dimensionally stable so that no distortion occurs when the thread bundle is bent. Such acrylic resins have bulk indices in the range of 1.48 to 1.51 and give light transmission in excess of 90 pounds per centimeter. With acrylic resins of high purity, a transmission of 90 # / 100 cm can be achieved. Many acrylic resins are soft or rubbery in nature. Such which or rubber-like (gum-like) acrylic resins are unsuitable for the purpose of the invention. The best criterion for the dimensional stability of acrylic resins under tension and elongation is the dimensional stability under heat (Heat Deflection Temperature), determined according to ASTM test standard D-648 at 18.5 kg / cm V / ärme is based on this test). The preferred acrylic resins for the formation of the yarn cores according to the invention have a dimensional stability under heat of Mohr than 55 ⁰ C bsi 18.5 kg / cm ² as determined according to ASTM-PrUfnorm 0-648. I;. R Suhroelzindex of the core is preferably in the range of 0.05 to 10 g / 10 min bsi g 200 ⁰ C and a load of 2160, determined according to ASTM test standard D-1238-57T. Such acrylic resins include polyalkyl methacrylates and

Misehpolyraeve, at least 70% contain Alkylmsthaerylfit, wherein the alkyl group has 1 to 6 carbon atom ^ contains, as polymethyl methacrylate, Polyäthylmethaory-Ifit, FolyprDpylmethacrylat, Polybutylmethaorylat, Polyisobutyj.inothi "üs ⁱ ylat and Polyoyclohexylmethacrylat entspreshende and mixed polymers. Examples of good polymers are

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Mixed polymers of methyl methyl aylate and up to 30% by weight of ethyl or methyl aorylate and up to 15% by weight of 2-ethylhexyl aorylate. Polymethyl methaorylate and corresponding copolymers with a content of polymethyl methaorylate of at least 70 % are available in high-quality form at moderate costs and are highly thermosetting and are preferred.

The jacket is required so that the thread cores do not touch one another and the light transmission accompanying contact with adjacent threads is avoided. The sheath preferably adheres to the core thread and is transparent. The orund for the transparency of the cladding results from the fact that opaque or translucent (but they tend to absorb part of the light and thus reduce the transmission of light. The refractive index of the cladding should be at least 3 % below that of the core, since Otherwise, light at the mantle-core interface will not be completely reflected back into the Ksrn and in this way the light transmission is reduced. A reduced light transmission also results if the mantle-core interface is not flawless. When using the acrylic resin threads mentioned above, the Jacket preferably has a refractive index below 1.43 to obtain a high light intensity image. Resins with a refractive index below 1.34 are theoretically brewable, but no corresponding resins are currently available. For the jacket, polymers made from the fluorinated esters of acrylic are preferred - or methaoryl acids of the structural formula

X (CF _{2) n} (CH _{2) m} 0C-C - CH ₂ OY

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wherein X belongs to the group P, H and Cl, η is an integer from 2 to 10 and m from 1 to 6 and Y is CH or H. A 3.2 mm thick plate of the core polymer should have a diameter of at least 80 % and a 2.2 mm thick plate of the shell polymer should have a thickness of at least 80% , each determined in accordance with ASTM test standard D-1003-59T.

The pad cores used according to the invention preferably have a diameter of 0.0013 to 0.64 mm, and the dioke the sheath is preferably 0.0012 to 0.13 mm. the finer orosses result in an otherwise smooth pactors better image reproduction and are two-fold for image guides, while the coarser orosses are easier to manufacture and for Light lines are not allowed. If the paten fineness is below about 0.0013 now drops (a value that sloh the wavelength approaching the light), the light is scattered and wilted more Transfer. The image reproduction becomes coarse above 0.13 mm. The threads become inflexible above 0.64 mm. When the cover dioke is less than 0.0013 mm, the soldering will not be correct because the dioke approximates the wavelength of light. With a Uberzugsdioke of more than 0.13 mm begins the coating is oversized in comparison with the pad cores Share of the Bundelquersohnittsfläche and will be the Amount of the thread core material to be transferred to one Reduced value, with dsm a reduced image brightness is obtained. The bundles can be made with a wide variety of thread counts getting produced. Sufficient for simple solder transfer a small number of large diameter threads. Thousands of threads each are required for high quality image transmission Bundle needed. As mentioned above, the thread ends are fixed to one another during the thread bundle formation. One can accomplish this by using a potting resin, like a Epoxy resin, a polyester resin or a solution of the

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Threads used covering material in a suitable Applies solvent. The coatings can also be fused together by applying heat and pressure brings about; Another method is to put a pair of binding elements in the bobbin before winding the threads and to tighten the binding elements around the threads after the threads have been wound up on the bobbin and to cut the threads between the binding elements in order to obtain the thread bundle which is to be transferred.

The light transmitting filaments of the invention are shown in FIG many ways of value. In the formation of an image transferor In bundled form, they are particularly suitable for medical examinations, bsi those that Bundle is introduced into the human body to do the to consider otherwise inaccessible body tissues, since the thread bundles according to the invention are much lighter and more flexible than olas fiber bundles and in this catfish for the Patients are less uncomfortable and, due to their greater flexibility, allow more diverse applications. Image guides formed from the threads according to the invention are only suitable for other telecommunication purposes, such as the Observation of work within a radioactive environment.

If the threads according to the invention in a random manner with » are combined with each other, bundles can be obtained at low cost, which are suitable for remote lighting and special lighting effects suitable.

The following examples serve to further illustrate the invention.

909850/15 10

ORIGINAL

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example 1

At 200.degree. C., a sheath-core composite thread consisting of a polymethyl methaorylate core and a sheath made of a fluoroalkyl metal aorylate polymer obtained by emulsion polymerization of 2 % n-butyl acrylate is passed through a spinneret as shown in FIG with 98 % of a telomer of the structural formula obtained according to US Pat. No. 2,628,938

P (CFgCPg) _n CH ₂ CHgOC-C - CH ₂ ,

wherein η is an integer from 3 to 5, prepared has been pressed out and wound up at such a speed that you get a composite thread with a through knife of 0.064 mm and a core diameter of 0.028 mm. This sheath-core thread shows excellent durability and abrasion resistance. The index of refraction of the poly methyl methaorylate core is 1.49 and that of the fluoronicyl / methaorylate polymer jacket about 1.36.

B e i s ρ 1 e 1 2

Using a spinneret according to FIG. 2 with a 1.3 mm outlet ^{opening, a sheath-core composite thread is pressed out at 200 °} C., which has a core made of a mixed polymer of 87 % methyl methacrylate and 1J% ethyl aorylate (with a melt index of 2 ^ 6 g / 10 min. At 200 ⁰ C and 2160 g load, determined according to ASTM test standard D-12? 8-57T, a dimensional stability in the heat of 71 ⁰ C, a

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Refractive index of 1.49, determined according to ASTM test standard D-542, and a Liohtdurehlässlkelt in the form of a 5.2 mm thick plate of 92 %, determined according to ASTM test standard D-1003-59T) and a sheath made of a fluoroalkyl methaorylate polymer (g with a Sohmelzindex of 21.3 / 10 min. at 200 ⁰ C and 325 g load, determined NaOH ASTM test standard D-1238-57T, a refractive index of 1.37 and a Llchtdurohlässlgkeit in the form of a 3.2 mm Dioken plate of 90 %, determined according to ASTM test standard D-1003-59T), the shell polymerizing by emulsion polymerisation of a telomer of the structural formula obtained according to the USA Patent No. 2,628,958

P (CP ₂ CPg) _n CH ₂ CH ₂ OC-C - CH ₃ ,

0 CH,

where η is an integer equal to 3 to 5, is prepared. The composite thread is wound up at such a high speed that its diameter is 0.05 mm (jacket thickness 0.0025 mm). The light transmission of this composite thread is 65 % / J> 0 om.

Example 3

Example 2 is repeated with the modification that the thread is wound up at such a speed that a composite thread Durohmesser of 0.25 mm (core diameter 0.23 mm and jacket thickness 0.013 mm) is obtained. This thread whose transmission rate is 90 # / 30 om, is suitable for Light guides up to 3.7 m in length. The threads obtained are tough and flexible and are made by the action of gamma radiation not damaged by ICr X-ray.

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Claims (1)

Today's claims 1. Lioht transferring thread from a core of 0.001? up to 0.64 mm in diameter, on which a jacket of 0.001? to O ₄ I? mm thickness is applied, characterized in that the core hard is an alkyl methaorylate polymer with a content of at least 70 % of alkyl methaorylate, the alkyl group containing 1 to 6 carbon atoms, and the shell resin is a polymer of a telomer of the structural formula 0 Y in which X is H, F or Cl, η is an integer from 2 to 10, m is an integer from 1 to 6 and Y is H or CH, mean. '. Thread according to claim 1, characterized in that the shell resin is a polymer of a telomer of the structural formula F (CP ₂ CP ₂ J _n CH ₂ CH ₂ OC-C - CH ₂ 1st, in which η is an integer from 2 to 5. New »Documents (* t - 11 - BATH ORIGINAL Ai. Blank page