JP2782376B2 - Manufacturing method of stretched tape - Google Patents

Description

The present invention relates to a method for producing a stretched tape containing polyethylene terephthalate as a main component and having excellent heat shrink resistance, excellent winding appearance, and small woven deterioration. The present invention also provides a method for producing a stretched tape useful as a woven yarn for various packaging bags, carpet base fabrics, and the like.

(B) Conventional technology Conventionally, stretched tapes made of polypropylene or the like have been woven and widely used as packaging materials for rice-wheat bags, cement bags, flexible containers, and the like, and as carpet base fabrics and the like.

However, in the recent carpet field, tile-type carpets in which a backing material is backed with a composition mainly composed of polyvinyl chloride or bitumen at a high temperature have appeared, and due to the backing at such a high temperature, The primary polypropylene fabric constituting the carpet shrinks significantly, causing troubles such as poor appearance of the carpet and poor dimensional stability.

Further, in the field of packaging bags such as flexible containers made of polypropylene, from the viewpoint of the heat resistance of polypropylene, direct filling with high-temperature materials has been refrained, and the demand for stretched tapes in the field has been hindered. Is the current situation.

On the other hand, at such a high temperature, a polyethylene terephthalate stretched tape may be used as a stretched tape that can maintain the required strength and the like with little deformation. In addition, there is a problem in that the winding appearance is poor and the weaving is difficult.

(C) Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned current situation,
An object of the present invention is to provide a method for producing a stretched tape which is excellent in heat shrinkage resistance, has excellent winding appearance, and has little weave deterioration.

(D) Means for Solving the Problems The method for producing a stretched tape of the present invention is described in detail below.
Polyethylene terephthalate with intrinsic viscosity [η] 0.7 to 1.1
A composition comprising 60 to 95% by weight and 40 to 5% by weight of a polypropylene having a melt flow rate of 1 to 10 g / 10 minutes is melt-extruded into a film at 260 to 290 ° C, cooled and solidified to form a film. Is cut in a tape shape, and then is stretched in the take-up direction at 60 to 110 ° C. in the range of 30 to 90% of the total stretch ratio in the first stage, and subsequently is stretched at 150 to 180 ° C. in the second stage. The film is stretched to a total draw ratio of 4 to 8 times, and then at 180 to 220 ° C for 10 to 10 times.
It is characterized by performing a 30% relaxation heat treatment.

The polyethylene terephthalate used in the present invention has [η] of 0.7 to 1.1, preferably 0.8 to 1.0. When [η] is less than 0.7, the tensile strength of the stretched tape is low, the winding appearance is poor, and the weave deterioration is large. On the other hand, if [η] exceeds 1.1, troubles such as breakage of stretching may occur during the production of the stretched tape.

As the polypropylene used in the present invention,
Melt flow rate is 1-10g / 10min, preferably 1.5-8
g / 10 minutes. If the melt flow rate is less than 1 g / 10 minutes, troubles such as stretching breakage will occur when the stretching ratio is increased. On the other hand, when it exceeds 10 g / 10 minutes, the stretched tape is shiny and has a slimy feeling, the winding appearance is poor, and the weave deterioration is large.

The polypropylene used in the present invention is preferably a homopolymer, but a copolymer of propylene and ethylene, butene-1 or the like, or a mixture thereof, as long as the physical properties of the stretched tape are not impaired. It may be.

The composition ratio of the polyethylene terephthalate and the polypropylene is 60 to 95% by weight, preferably 65 to 95% by weight.
-90% by weight, the latter being 40-5% by weight, preferably 35-10% by weight. If the latter polypropylene is less than 5% by weight,
The stretched tape is shiny and has a slimy feeling, the winding appearance is inferior, and the weave deterioration is large. on the other hand,
If it exceeds 40% by weight, the heat shrinkage rate will deteriorate.

The method for producing a stretched tape of the present invention comprises the step of mixing the polyethylene terephthalate and the polypropylene, if necessary, with a heat stabilizer, a light stabilizer, a UV inhibitor, a lubricant, a blocking inhibitor, a flame retardant, an antibacterial agent, a pigment, And an inorganic filler and its dispersing agent are added, melt-kneaded to form a composition, melt-extruded into a film using a known molding machine using a T-die, a circular die, etc., and cooled and solidified. After forming into a film, the film is cut into a tape shape, and then, in a take-off direction, a hot roll stretching machine, an oven stretching machine,
The film is stretched at a total stretching ratio of 4 to 8 times at a high temperature using a usual stretching machine such as a hot plate stretching machine, and then subjected to a relaxation heat treatment.

Here, in the present invention, the extrusion temperature of the composition is
260-290 ° C, preferably 270-280 ° C. Extrusion temperature
If the temperature is lower than 260 ° C., the extruded amount is reduced and the film surface is roughened, and further, troubles such as breakage in stretching during the production of the stretched tape occur. On the other hand, when the temperature exceeds 290 ° C., it is difficult to obtain a film having a uniform thickness.

In the present invention, the stretching in the take-off direction is performed in two stages. In the first stage, the stretching is performed at 60 to 110 ° C., preferably 65 to 100 ° C., and 30 to 90% of the total stretching ratio, preferably The film is stretched in the range of 35 to 85%, and in the second stage, 150 to 1%.
80 ° C., preferably 155-175 ° C., 70-10% of the total draw ratio
%, Preferably in the range of 65 to 15%. If the temperature of the first-stage stretching is lower than 60 ° C., stretching breakage occurs, while
When the temperature exceeds ℃, vertical wrinkles occur, and it is difficult to obtain a tape having a uniform tape width. Also, the magnification of the first stage stretching is 30% of the total stretching ratio.
%, The tensile strength is low, and the appearance of the roll is also reduced.
Weaving deterioration is also large. On the other hand, if it exceeds 90%, the heat shrinkage ratio is deteriorated, and the appearance of the roll is also deteriorated. Furthermore, the temperature of the second stage stretching is 15
If the temperature is lower than 0 ° C., the heat shrinkage rate is deteriorated. On the other hand, if the temperature exceeds 180 ° C., stretching breakage occurs.

Further, in the present invention, the relaxation heat treatment is 180-220.
C., preferably at 190 to 210.degree. C., with a relaxation of 10 to 30%. If the processing temperature is lower than 180 ° C., the heat treatment rate is large, while if it exceeds 220 ° C., the tape breaks. When the relaxation rate is less than 10%, the heat shrinkage rate is large, and when it exceeds 30%, the tensile strength decreases.

(E) Function and Effect The method for producing a stretched tape of the present invention has a high tensile strength and a high heat-shrinkage property by using polyethylene terephthalate as a main component and performing stretching in two stages under specific conditions. Excellent, furthermore, the intrinsic viscosity [η] of the polyethylene terephthalate is in a specific range, and by using the composition with the polypropylene having a melt flow rate in a specific range, the winding appearance is also excellent, and This makes it possible to produce a stretched tape with little weave deterioration.

(F) Examples Examples 1 to 8, Comparative Examples 1 to 11 Polypropylene was mixed with polyethylene terephthalate dried at 150 ° C. for 4 hours using a hot air circulating dryer.
Using a 65 mmφ extruder, melt extrude into a film at 270 ° C. with a T-die, cool and solidify while taking off at a speed of 20 m / min to form a film, cut the film into a tape, First in the take-off direction at 90 ° C by hot plate stretching machine
Step stretching, followed by a second step stretching at 170 ° C. by an oven stretching machine and stretching to a total stretching ratio of 5.2 to 5.8 times, and then performing a relaxation heat treatment at 190 ° C. in an oven to give 1200 denier Was produced. In this case, the intrinsic viscosity [η] of polyethylene terephthalate, the melt flow rate of polypropylene, the composition ratio of both, the respective draw ratios in the first and second stages, and the relaxation ratio are as shown in Table 1. And

Table 1 shows the results of evaluation of the tensile strength, heat shrinkage, and winding appearance of the obtained stretched tape, such as a feeling of shine, a slimy feeling, and irregularities.

Here, the tensile strength was measured according to JIS Z1533, and the heat shrinkage was 1% in an oil thermostat at 200 ° C.
The shrinkage after immersion for 0 minutes was measured. or,
The winding appearance was visually determined.

In addition, using the stretched tapes of Examples 4, 6, 8 and Comparative Examples 4, 9, and 10, both the warp and the weft yarns were formed on a through-type loom.
A plain woven fabric was woven at a rate of 12 yarns / inch.

Table 2 shows the measurement results of the tensile strength and the weaving deterioration rate of the obtained woven fabric.
It was shown to.

In addition, each of these physical properties was measured by the following method.

Tensile strength; Weaving deterioration rate according to JIS L1068;

Claims (1)

(57) [Claims] (1) A polyethylene terephthalate having an intrinsic viscosity [η] of 0.7 to 1.1 is 60 to 95% by weight and a melt flow rate is 1 to 10%.
g / 10 minutes of polypropylene with 40-5% by weight of 260
Melt extruded into a film at ~ 290 ° C, cooled and solidified to form a film, cut into a tape, and then in the take-off direction at 60-110 ° C with a range of 30-90% of the total draw ratio. In the first step, and subsequently in the second step at 150 to 180 ° C. to stretch the film at a total stretching ratio of 4 to 8 times, and then, at 180 to 2 times.
A method for producing a stretched tape, wherein a relaxation heat treatment of 10 to 30% is performed at 20 ° C.