KR800000912B1 - Method preparing a bulked film-fiber - Google Patents

Abstract

A process of cold drawing a shaped plastic sheet where in said sheet has a plurality of hollow pointed projections on one or both faces arranged in an array that forms parallel rows in at least one direction, said hollow pointed projection having at least a portion of the distal portion of the sides at an angle of over 60≰to the median plane of the sheet which process comprises cold drawing the shaped plastic sheet by stretching the sheet along an axis in the median plane of the sheet and normal to a direction of parallel rows of projections to produce an oriented plastic sheet containing projections which remain incompletely drawn.

Description

Manufacturing method of sublime film fibers

The present invention relates to a method for producing a film fiber sublimated by cold drawing. The production of film fibers is well known in the art, and the method for producing the fibers is cold stretching of a suitable plastic film, highly orienting the film according to the stretching direction, and finally fibrillating to make a tape or fiber. Such techniques are detailed in “Textiles from Film” (British Council Plastics Association July 1971) (vol. 2).

It is noted that for the purposes of many fabrics it is desirable to sublime the fibers by forming regular and large deflections in the straight direction of the fibers and fixing them in the fibers. In one-dimensional tissues such as elongated fibers, sublime refers to forms of crimps, coils, and loops, that is, geometric shapes that are easily tensioned and straightened like springs.

The film fibers can be sublimed by various methods such as passing them through an occlusal gear or a vapor stuffing box. All known methods of subliming the film fibers are sublimation after cold stretching the fibers, and the sublime fibers prepared by this method have a discontinuity in which the twisted fibers are unfolded or become straight due to the loss of the subliminal gland.

The inventors have invented a method of cold stretching a molded plastic sheet to obtain a sublime film fiber product that does not lose its sublime properties even under tension.

The present invention is a plastic sheet molded to have a row of hollow peak protrusions arranged on a plurality of substantially parallel one side or both sides, wherein at least a portion of the side end portions of the hollow peak protrusions is formed on the center surface of the sheet. Provided is a method for producing a sublime film fiber, wherein the molded plastic sheet having an angle greater than 60 ° is cold drawn along an axis in the sheet surface perpendicular to the rows of the hollow protrusions.

Peak means that the surface area of the apex is small compared to the surface area of the protrusion. Therefore, the peak of the projection may be sharp or dull or may be a small section plane. In some cases, as described in Example 8, the peak may be subjected to work deformation before stretching.

Cold stretching of a molded plastic sheet having a peak as described above causes the material in the center plane of the sheet to be drawn like the material in the smallest part of the sheet plane adjacent thereto but is greater than 60 ° with respect to the center plane. The material on the side of the protrusion showing the angle becomes the sharp pointed spine as opposed to cold stretching, and remains in the tape fiber as it is.

Since any of the fibers with the spines are obtained, the exact shape of the hollow tip is not important to the present invention, but the properties of the fiber obtained vary depending on the exact shape of the protrusion. As long as possible, it is preferable that the inclination angle with respect to the central part of the projection is smaller than the distal end. The hollow peak projection is conveniently in the form of cusps. Cuspras means irregular hollow cones with indented faces. The protrusions may be interspersed, but generally a series of cusps are connected to form the sheet, with little or no non-molding zone in the sheet surface. It was found that the physical properties of the molded sheet corresponded to the inclination of the cusp during cold drawing. Cuffs with an average inclination of 30 ° or less are almost completely reabsorbed when cold drawn to 6 times or more, leaving a slight wave shape and remaining on the alignment film. Cold stretching when the inclination angle is around 45 ° results in an inclination of 10 ° to 15 °. However, the steep incline of 60 ° to 80 ° is rarely reabsorbed. Moreover, this depends on the temperature, the higher the cold draw temperature, the greater the resorption of cusps.

The size and shape of the splintered filaments obtained by the method of the present invention can be controlled by the shape, thickness and frequency of the projections and the temperature and degree of cold drawing. In any case, the portion of the cusp that is to be left after cold drawing should be an angle larger than 60 ° and preferably larger than 70 ° with respect to the original film plane. Furthermore, the base of the cusp should be at an angle of less than 60 °. These cusps are usually placed on a molded plastic sheet in a regular grid, for example, in a square lattice, and these cusps may be directed upwards and downwards (not necessarily the same number) or all in one direction. You may be heading for. In addition, the axis of a cusp does not necessarily need to be perpendicular | vertical to a sheet surface, but may be inclined. If inclined, the distal end of the side shall be no more than 30 ° relative to the axis of the cusp.

The premature unit filament should be equal in width to the cusp on the strip and the thickness should be suitable for drawing the cusp. The width of the cusp base is the width of the annular base of the cone surrounding the cusp. The actual cusp width must be at least twice the thickness of the material required to form the cusp. In addition, since the ratio may be higher, the initial material unit filament is a tape having a thickness and width of 1: 2 to 1:10.

The molded plastic sheet may be torn into unit pieces before cold stretching, or may be opened or fibrillated after the entire sheet is stretched as it is. The amount of stretching required for cleavage or fibrillation has been well known among film fiber manufacturers. When the molded plastic sheet is stretched, first, a flat surface of the cusp sidewall or the raw film portion between the cusps causes undulation, and the stretching continues until the molecular orientation reaches a predetermined level. It was found that it did not reach the high zone. The main reason is that the material in the elevation region is at a position substantially perpendicular to the direction of tension and loops or loops of the oriented material are formed around the cusp base, preventing the tension from reaching the elevation scuff. The mechanical action of the cusp when drawing is to act as a through-hole with a thick flange in the tape.

내지

정도로 감소한다.The molded sheet is usually drawn by m times (m is usually 4 to 6). Corresponding to this, the cross-sectional area of the sheet is reduced and the width and thickness

To

Decrease to a degree.

When the molded sheet is stretched when the cusp peak is thick and the cusp sidewall is thin, a stretched filament having a relatively light weight structure can be obtained even if the sheet does not break or break. To obtain structurally more effective filaments, the cusp apex has a relatively thin wall, the cusp sidewalls with a gentle slope near the cusp base are thicker, and the sidewall of the cusp is approximately perpendicular to the sheet plane. Should be made. It is desirable to produce barbed filaments with controlled weight ratio of barbed fibers. It is easy to make the weight ratio of the visible fiber 10% or less by producing a thin and steep cusp. There is also a limit on the visible frequency in the sufficiently drawn fibers. At least a portion of the stretched fiber body is usually derived from the cusp sidewall, so if it is elongated by m times, the structurally balanced spine filament has a shorter run time of about 2 pm (p is the peak of the unstretched sheet). Distance and m is the draw ratio).

The plastic sheet used in the present invention is molded by any known method. Particularly useful molding methods are described in Belgian Patent No. 792,077.

In this method, a sheet of thermoplastic material is heated using plastic capable of melt spinning, and an array of cold projections is provided on one side of the heated sheet, and a second array of cold projections is provided on the other surface of the heated sheet. The two arrays are pressed into each other by compression. At this time, the distance between the projections on the two arrays is greater than or equal to the thickness of the sheet, so that the sheet is deformed to form a molded sheet. Suitable plastics for melt spinning include, for example, low density polyethylene high density polyethylene, polyeth ylene terepthalate, nylon 6, nylon 66, nylon 610 and polypro pylene.

According to the method described in Belgian Patent No. 792,077, a plastic sheet having a cusp on one or both sides and having a suitable wall thickness of the cusp can be produced. The exact conditions required of the cusp with the approximately vertical side desired can be found by a simple preliminary experiment as in Example 4.

The molding sheet is modified by the method of Belgian Patent No. 792,077 so that one of the protrusion arrays is an array of needles and the other of the projection arrays is an array of tubes, and the pressure is inclined to the center of the tube to form a cusp. I can make it. The molded sheet may also be produced by a vacuum molding method in which the deformed plastic sheet is pressed onto the protrusion array by a difference in fluid pressure, or by a casting method in which a molten layer of plastic is cast directly on the needle array.

Engraving, grooves, embossing, notches (figure 3) on the initial material film, with the main purpose of promoting fibrillation or forming fibrillation other than rectangular cross-sections in order to make regular strands in film fiber manufacturing technology. notch) is known. However, these techniques use a relatively thin solid ejection shape, which is completely different from the present invention using a hollow projection that is deeply stretched. In these techniques of preloading, all materials are drawn, but the cusp remains undrawn in the method of the present invention.

The product obtained by this method has not been obtained by any method conventionally. The fibrillated or unfibrillated cold drawn plastic sheet thus obtained by the process of the invention is new. The cold drawing degree can be changed in various ways. The sheet may be stretched until it is fibrillated, or the sheet may be stretched to such an extent that the fibrillation is not sufficient. In either case, the stretched sheet is incompletely stretched into a tape of uneven orientated material due to the remaining protrusions. This tape and the film fibers made therefrom do not lose their sublime properties even under tension. Therefore, there are many uses that are not found in the fibers obtained by the known film fiber method.

束) 및 섬유간의 슬립에 의한 긴장시에 무너지지 아니하는 스프사를 제조할 수 있다. 플라스틱포옴(foam), 포오틀란드시멘트, 소석고, 열경화성 수지, 저융점합금의 보강재로 사용하면 이들의 테이프, 섬유 및 전부 또는 일부가 이들에 기인된 실이나 직포는 화학적 접착에 관계없이 가시부설 섬유에 의하여 결합한다. 특히 본 발명에 의한 테이프 또는 섬유는 성분들간의 상호작용에 의해 물리적으로 엉키게 되는 복합계에서 특별한 효과를 나타낸다. 예를들면 파티클보오드나 스토운 칩(stone chip) 등을 수지로 결합한 바와 같은 수지결합 과립상물 구조체에서는 충진재 입자 사이의 평균 공간을 섬유의 지름이 되게 하고 가시가 기계적으로 파지되게 한다. 다시 본 발명에 의한 섬유를 입자계의 소량성분으로 하여 사용하면 계(系)의 슬럼프 특성(slump characteristics)과 휴식각(angle of repose)이 달라질 것이다. 따라서 그들 섬유는 뭉쳐진 점토, 토양 및 같은 계를 강화하고 부식에 대하여 그들을 안정시켜 준다. 또한 본 발명에 의한 섬유나 테이프는 혹이 있는 지지체로 작용하고 피지지체가 혹상에 매달리는거와 같은 작용을 하므로 함께 주형한 성분을 견고하게 교합한다. 본 발명에 의하여 냉연신된 시이트의 또 다른 예기치 못한 특징은 돌기가 피브릴화를 정지시키는 작용을 하므로 돌기 부분에서 다수의 섬유와 테이프가 결합한 시이트가 얻어지도록 실시할 수 있다. 이러한 형태의 시이트는 실의 특성이 있고 특히 염가하여 제조하기 쉬운 이익이 있는 것이다.Tapes or fibers obtained in this method have spines or bumps that impart slip resistance when used. In such a fiber, it is literally sublime thread or

I) and a soup thread which does not collapse during tension due to slip between fibers. When used as a reinforcement for plastic foam, portland cement, gypsum, thermosetting resins, and low-melting point alloys, these tapes, fibers, and all or part of the yarn or woven fabric resulting from them are visible fiber fibers regardless of chemical bonding. Joins. In particular, the tapes or fibers according to the invention have a particular effect in composite systems which are physically entangled by the interaction between the components. For example, in a resin-bonded granular structure in which particle boards, stone chips, or the like are bonded by resin, the average space between filler particles is the diameter of the fiber, and the spines are mechanically gripped. If the fiber according to the present invention is used again as a small component of the particle system, the slump characteristics and angle of repose of the system will be different. Thus their fibers strengthen the agglomerated clay, soil and the same system and stabilize them against corrosion. In addition, the fiber or tape according to the present invention acts as a support having a bump and acts as if the supported body is suspended on the wound, so that the mold components are firmly interlocked together. Another unexpected feature of the cold drawn sheet according to the present invention is that the projection serves to stop the fibrillation, so that the sheet in which the plurality of fibers and the tape are combined at the projection can be obtained. Sheets of this type have the properties of yarn and are particularly advantageous at low cost and easy to manufacture.

Next, the present invention will be described according to specific examples, but these examples do not limit the present invention.

Example 1

This example is not an embodiment of the present invention but illustrates the manufacture of a plastic sheet suitable for cold drawing. Two sets of arrangements in which sharp needles were arranged in a square were mounted on a lightweight hand press which can polymerize each part accurately. Both upper and lower arrays were positioned so that any needle in the upper tank could enter the center of a square formed by four needles in the lower tank.

In other words, both arrays were arranged so that the same protrusions were formed. The length of the unit square in each arrangement was 1/2 inch and the height of the needle was 1 inch. A polyethylene film sample was placed in an open frame made of a hinged quadrangular ring, which was placed near a radiant heat plate, heated and melted to a thermal temperature, and then quickly inserted between operating parts of the press. Both arrays of ambient temperature were engaged under low pressure. Shaped bodies with peaks different in direction from each other were formed. A polyethylene film having a thickness of 0.006 inches to 0.100 inches can be stretched to a depth of 1 inch, and the surface area increase at that time reached 900%. The drawing speed that yielded the best results was that the molding mold took 1 to 2 seconds for 1 inch interpenetration. Careful examination of the sample section of the apex obtained under such conditions showed that the maximum elongation occurred in the central region, and that the apex of the apex was not relatively thin. The same result was obtained using the sheet of polypropylene.

Example 2

The experiment of Example 1 was repeated using an array of thin needles with a needle spacing of 0.08 inches and a needle height of 0.4 inches, thereby obtaining a sheet having a velvety surface, which had been subjected to a delicate structure of apex.

Example 3

Polypropylene sheets of various thicknesses were used to produce sheets with peak projections according to the methods of Examples 1 and 2. These sheets were heated in an oven to a temperature of 120 ° -170 ° C. and elongated at a rate of 3 to 100 feet / minute until the length increased by 10 times.

Example 4

This example illustrates the production of molded plastic sheets suitable for the cold drawing method. The peak protrusion forming apparatus was assembled by mounting two sets of identical sharp needle planar arrays in a manual press. The upper and lower arrangements were arranged so that any needle in the upper tank could enter the center of the square formed by four needles in the lower tank. In other words, both arrangements were arranged so that the same protrusions were formed. The needle shape of each arrangement was a square lattice in which one axis was parallel in the stretching direction, and the distance between the needles was 0.100 inch, the diameter of the needle was 0.028 inch, and the length was 0.600 inch. A 0.024 inch thick polypropylene film held in a hinged open frame made of a hinge was placed near a radiant heat plate, heated and melted to a thermoforming temperature, and then quickly inserted between operating parts of the press. The press was adjusted so that the needle arrays penetrate each other by 0.240 inches. Various sheets were used to produce sheets having peaks from completely different materials, from needle penetrating to peaks becoming too thick so that little material remained in the neutral axis of cold drawing. It was found that warming the needle in a prewarming oven such that the needle was initially 20 ° to 40 ° C. below the curing temperature of the plastic was a decisive means of controlling the weight and material distribution of the tip. Elongation speed is also important and good results have been obtained by limiting the mold to about 2 inches per second. The peaks protruding substantially vertically with the concave side under conditions close to these best conditions were obtained. The plastic thickness of the plastic decreased by 50% at the side of the protrusion. The molded sheet is cut into strips in the middle of the array of peaks, and then cold drawn to 120 ° C. to produce a filament of about 90 tex. This filament had a strong peak and the gap was about 0.600 inches after stretching 12 times. The filaments were tensioned, but no cuts were made at the particular position related to the spine, and the results of experiments to determine the best condition are shown in the following table.

Example 5

A square lattice with air vents was installed in a vacuum forming machine with a stainless steel needle with a high angle of 45 ° and a sharp edge of 0.048 inch in the direction of drawing. One side of the unit square of the vacuum forming apparatus is 0.200 inches and the needle length is 0.030 inches. The partially drawn polyethylene terephthalate sheet of 0.030 inch thickness was prepheated to thermoforming temperature and quickly clamped into the mold of the vacuum forming apparatus and then depressurized for 0.5 seconds. The sheet having the apex on the one side thus obtained was reheated and stretched 5 times to orient the material. Similar specimens drawn 10 times were made using polypropylene.

Example 6

The tendency of gently refracting and evenly rubbing the polyvinylated cold-drawn stretched film of polypropylene prepared as in Examples 3 to 5 was improved. The spines act to stop the fibrillation, but the sequence of spines is very easy to see. As in Example 5, when the peak body is inclined with respect to the stretching axis, the network structure tends to be obtained by fibrillation.

Example 7

Experiments were carried out using 0.060 inch thick polyethylene terephthalate film prepared by weight extrusion and partially biaxially oriented. The molded plastic sheet was prepared in accordance with the general method of Example 4 using a peak-protrusion mold of a square lattice design in which one side of the unit square was 0.200 inch. The needle used was a 1,500-inch long Chenille needle that was extremely sharp and thin. The intention was to investigate the effects of extremely deep vertical stretching, and polyethylene terephthalate was particularly suitable for this purpose.

A thin, deep apex with a depth-to-base ratio of 8 was prepared. Careful experiments resulted in stretching the denser sheets. At this time, however, the weight ratio of the projections was extremely high (about 2: 1), and there was little material for stretching between the projections. The situation was remedied by lowering the stretching speed and reducing the temperature difference between the heating sheet and the needle array, but the whole method had to be carried out slowly at the temperature controlled near the melting point of the plastic. The results of this experiment concluded that even fibers with good spines balanced with deep spines could be produced.

Example 8

Peaks, especially those with depth-to-basewidth ratios greater than 4, could be deformed before or after cold stretching without altering the strength and uniformity of the fibers. Using the material described in Example 7, the projection peak was removed, or heat leveling or heatsealed to form a projection peak without cutout. It was also possible to flex the material while adjusting the temperature to curl the peaks to form hooks or other forms. Such operations do not alter the cold stretchability of the film with the peaks as long as they limit the object to the elevation of the peaks. It was also found that the use of a slightly dull pin yields rounded or flattened peaks, while in the case of unbalanced peaked protrusions, increasing the mass of the used sheet does not deteriorate the ductility and material distribution, but provides a useful product.

Claims (1)

A plastic sheet molded so as to have a line of hollow peak protrusions arranged in substantially parallel multiple strands on one side or both sides as described above in the text, and at least part of the side end portions of these hollow peak protrusions. A method for producing a sublime film fiber, wherein the molded plastic sheet having an angle greater than 60 ° with respect to the central surface of the temporary sheet is cold drawn along an axis in the sheet surface perpendicular to the rows of the hollow protrusions.