JP2003170495A - Heat-shrinkable polyester film roll and method for producing the same - Google Patents

Abstract

(57) [Summary] A heat-shrinkable film roll excellent in workability by reducing occurrence of breakage trouble in a processing step due to fluctuation of a breakage rate of a long film wound on a film roll. And a method for producing the same. SOLUTION: For a film roll obtained by winding a heat-shrinkable film, a test specimen cut out from the heat-shrinkable film under predetermined conditions is subjected to a tensile test in a direction orthogonal to the maximum shrinkage direction of the film. Chuck distance 10
0mm, specimen width 15mm, temperature 23 ° C, tensile speed 20
When the test was performed under the condition of 0 mm / min, the number of test pieces having a breaking elongation of 5% or less was 10% or less of the total number of test pieces in each cutout portion in any cutout portion.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a film roll formed by winding a heat-shrinkable polyester film. More specifically, it is a roll wound with a heat-shrinkable polyester film showing a uniform composition over substantially the entire length of the film, and is further caused by fluctuations in tear resistance in the heat-shrinkable film roll. The present invention relates to a heat-shrinkable film roll having very few troubles such as breakage in the post-processing step.

[0002]

2. Description of the Related Art Heretofore, heat-shrinkable films have been widely used for applications such as shrink wrapping and shrink labels by utilizing the property of shrinking by heating. Among them, the polyester stretched film is polyethylene terephthalate (PET).
In various containers such as containers, polyethylene containers and glass containers, it is used for the purpose of label, cap seal or integrated packaging.

[0003] These heat-shrinkable films are once wound into a roll after being manufactured, and are sent to a printing process of various designs in the form of this film roll, and after printing is finished, if necessary, a final product. The slits are processed according to the size of the label or the like used for, and the left and right ends of the film are further overlapped and sealed into a tubular body by means of solvent adhesion or the like, and the tubular body is cut, and the label, It is processed into a bag.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have made diligent efforts to prevent heat shrinkage behavior, solvent adhesion behavior, and the like of a long film wound on a single roll from varying over the entire length of the film. As a result of study, it was found that it is important to suppress the compositional variation of the film as much as possible and to strictly control the film surface temperature in the stretching process, and already filed an application (Japanese Patent Application No. 2002-123728).

However, even if the means disclosed in the above-mentioned application is adopted, when the raw material polyester contains a large number of units for increasing the degree of amorphization, the film is not formed in the processing steps such as printing, slitting, solvent adhesion and the like. Occasionally there was a problem of breaking. It is considered that this is because the tear resistance of the film varies within the film roll.

In view of the above, an object of the present invention is to provide a heat-shrinkable polyester film roll in which the fluctuation of the tear resistance of the film in the roll is small in order to reduce the occurrence of troubles in the above respective steps.

[0007]

The present invention is a film roll obtained by winding a heat-shrinkable polyester film, wherein the raw polymer of the heat-shrinkable polyester film is different from the main constituent unit. Of one or more secondary constituent units of the film, the end of the film on the winding start side is the first end, and the end on the winding end side is the end in the steady region where the physical properties of the film are stable in the length direction of the film. When the part is the second end, the first sample cutout is provided within 2 m inside the second end, and the final cutout is provided within 2 m inside the first end, and the first cutout is provided. A sample cutout is provided about every 100 m from the sample cutout, and 10 cm × 10 from each sample cutout.
A sample cut out in a square shape of cm was immersed in warm water of 85 ° C. for 10 seconds and pulled up, and then immersed in water of 25 ° C. for 10 seconds and pulled up, and the heat shrinkage ratio in the maximum shrinkage direction was
It is 20% or more for all the samples, and a plurality of heat-shrinkable film test pieces are separately cut out from each of the sample cut-out parts, and a tensile test is performed on the test pieces in a direction orthogonal to the maximum shrinkage direction of the film. , Chuck distance 10
0 mm, test piece width 15 mm, temperature 23 ° C., pulling speed 20
The point is that the number of test pieces with a breaking elongation of 5% or less in each sample cutout portion under the condition of 0 mm / min is 10% or less of the total number of test pieces in each sample cutout portion.

It can be seen that the film roll having such characteristics exhibits excellent tear resistance over the entire length of the film. Hereinafter, the numerical value representing the number of test pieces having a breaking elongation of 5% or less with respect to the total number of test pieces as a percentage may be simply referred to as “breaking rate”.

The main constituent unit is an ethylene terephthalate unit, and the subsidiary constituent unit is
It is preferable that at least one unit selected from the group consisting of neopentyl glycol and terephthalic acid, the unit consisting of 1,4-cyclohexanedimethanol and terephthalic acid, and the unit consisting of 1,4-butanediol and terephthalic acid. If such a combination of polyesters is adopted, the fluctuation of the breakage rate may increase, but
According to the present invention, this variation can be suppressed. In addition, the heat shrinkage property is also improved, which is a preferred embodiment of the present invention.

Further, the maximum heat shrinkage stress value in the maximum shrinkage direction of each sample appropriately cut out from each of the above-mentioned sample cutout parts was measured in hot air at a temperature of 90 ° C. and a blowing speed of 5 m / sec, a sample width of 20 mm, and a gap between chucks. The maximum heat shrinkage stress values of all samples were 3.0 MPa or more when measured under the condition of a distance of 100 mm, and the maximum heat shrinkage stress values of all samples were calculated when the average value of these maximum heat shrinkage stress values was calculated. It is preferable that the value is within ± 1.0 MPa of this average value. The heat-shrinkable film roll having the above properties has excellent shrink finish over the entire length of the constant region of the film, and in the heat-shrinking step, fluctuations in the maximum heat-shrinkage stress value of individual labels, bags, etc. Because there are few
An extremely stable shrink finish appearance can be obtained, and product defects can be reduced.

The film roll of the present invention has a width of 0.
A heat-shrinkable polyester film having a length of 2 m or more and a length of 300 m or more is preferably wound. This is because the film having the above width and length is likely to change the breakage rate of the film unless the present invention is applied, and it is meaningful to apply the present invention. In addition, it is excellent in processability and handleability in the printing process and the processing process up to the final product.

The preferred production method for obtaining the heat-shrinkable polyester film roll of the present invention in which the variation of the breaking ratio is small is that the intrinsic viscosity of the raw material polyester is 0.5 to
In the range of 1.3 dl / g, and controlling so that the difference X-Y between the intrinsic viscosity X of the raw material polyester and the intrinsic viscosity Y of the obtained film is 0.08 dl / g or less. Have a gist. When the intrinsic viscosity of the raw material polyester decreases due to thermal decomposition or hydrolysis during the extrusion process, the rupture rate of the obtained film varies, but if the extrusion process is performed by controlling so as to satisfy the above requirements. Therefore, it is possible to suppress the variation of the fracture rate.

In order to suppress the decrease in intrinsic viscosity, it is preferable to use a polyester having a water content of 100 ppm or less as a raw material. Further, the compounding of an antioxidant is also a preferable means.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have studied various problems caused in the steps of manufacturing labels, bags and the like from the heat-shrinkable polyester film and in the heat-shrink step, and found that these defects are It was found that the raw material polymer (1) is not a homopolymer but a polymer containing a secondary constituent unit in addition to the main constituent unit obtained by copolymerization or blending. That is, it was considered that the composition change of the polymer occurred in the long film, and this was one of the factors contributing to the change of the heat shrinkage behavior.

It has been found that a heat-shrinkable polyester film roll manufactured by using a specific means has a small change in composition and a change in heat-shrinking behavior and does not cause the above-mentioned problems. Japanese Patent Application 2002-123728
No .; hereinafter referred to as "first application"). The method for suppressing the compositional variation over the entire length of the film roll disclosed in this prior application is as follows.

[Composition fluctuation suppressing means] When polyester chips having different homogenizing compositions are used by blending, the shapes of the raw material polyester chips are made uniform.
As a result, segregation of the raw material in the hopper is suppressed. Specifically, in an elliptical columnar chip having an elliptical cross section, the average major axis (mm), the average minor axis (mm), and the average chip length (mm) of the elliptical cross section of the raw material chip of the polymer used most are compared. Then, the chips whose average major axis (mm), average minor axis (mm), and average chip length (mm) of the other chips are within ± 20%, more preferably within ± 15%, are used.

Optimization of the hopper shape The funnel-shaped hopper of the extruder, especially the final hopper (directly above the extruder /
Set the inclination angle of the previous hopper) to 65 ° or more. As with the small chips, the large chips are more likely to fall and the segregation of the raw materials can be suppressed. A more preferable inclination angle is 70 ° or more.

Optimization of Hopper Capacity A hopper is used within the range of 15 to 120% by mass of the discharge amount per hour of the extruder. This is because a hopper that is capable of supplying the raw material in a stable manner and that does not accumulate chips for a long time is suitable. A more preferable hopper capacity is 1 for the extruder.
It is 20 to 100% by mass of the discharge amount per hour.

Reduction of the amount of fine powder The amount of fine powder generated by chipping or the like is used as the raw material 100
The content is reduced to 1% by mass or less, more preferably 0.5% by mass or less. Specifically, the fine powder may be removed using a sieve, a cyclone type air filter or the like.

By suppressing the compositional variation by each of the above-mentioned methods (1) to (4), the heat shrinkage behavior can be made extremely uniform, and further, each of the preheating step at the time of stretching, the stretching step and the heat treatment step after stretching. In the step, if the fluctuation range of the surface temperature of the film measured at each arbitrary point is controlled within the average temperature ± 1 ° C, the fluctuation of the heat shrinkage behavior of the film can be further suppressed. In order to control in this way, for example, a wind speed fluctuation suppressing facility equipped with an inverter so that the wind speed of the hot air of the tenter can be controlled, or a heat source of 500 kPa or less (5 kgf / cm
^It is advisable to use equipment that can suppress the temperature fluctuations of hot air using low pressure steam ( ² or less).

In the above-mentioned prior application, it was judged whether or not the composition variation was suppressed over the entire length of the long film wound on one roll, based on whether or not the following requirements were satisfied. (1) The thermal contraction rate in the maximum thermal contraction direction (details will be described later) of each sample cut out from the sample cutout provided at regular intervals over the entire length of the film is 20 for all samples.
% Or more, (2) For each sample cut out from the sample cut-out portion, all the samples when the content ratio of the largest number of secondary constituent units contained in the largest amount of the secondary constituent units is measured The content of the largest number of secondary constituent units is 7 mol% or more in 100 mole% of all constituent units, and when the average value of these is calculated, the content of the largest number of subsidiary constituent units of all samples is ± 2 of this average
Within the range of mol%, (3) For each sample cut out from the sample cutout portion, the content rate of the second secondary constituent unit contained in the second largest amount of the secondary constituent units is determined. When measured, the content of the second subsidiary constituent unit in all the samples was 5 mol% or more in 100 mol% of all the constituent units, and when these average values were calculated, The content of 2 secondary constituent units is within ± 2 mol% of this average value. (4) A tube is made by solvent-bonding 1,3-dioxolane from a film roll (see the prior application for details. When the solvent adhesive strengths of the respective samples cut out from the sample cutout portion at regular intervals are measured, the solvent adhesive strengths of all the samples are 1 N / 15 mm width or more, and the average value of these is calculated. , Solvent adhesive strength of all the samples is within a range within ± 2N / 15 mm width of the average value,
(5) When the glass transition temperature is measured for each sample appropriately cut out from the sample cutting portion described in the requirement (1) and the average value of the glass transition temperatures is calculated, the glass transition temperatures of all the samples are the average. It is within ± 4 ° C of the value.

Also, in the above-mentioned prior application, whether or not the fluctuation of the thermal shrinkage behavior is suppressed in addition to the composition fluctuation is judged by whether or not the following requirements are satisfied. (6)
When the average value of the heat shrinkage ratios in the maximum shrinkage direction was calculated for each sample cut out from the sample cutout part described in the requirement (1), the heat shrinkage ratios of all the samples were ± 5% of this average value. When the maximum heat shrinkage stress value in the maximum shrinkage direction (details will be described later) is measured for each sample that is appropriately cut out from each sample cutout part described in (7) Requirement (1) within the range of (7) , The maximum heat shrinkage stress values of all the samples are 3.0 MPa or more, and when the average value of these maximum heat shrinkage stress values is calculated, the maximum heat shrinkage stress values of all the samples are ± 1 of this average value. When the heat shrinkage rate in the direction orthogonal to the maximum shrinkage direction was measured for each sample cut out from each sample cutout part described in (8) Requirement (1), which is within the range of 0.0 MPa or less, all Shrinkage rate of the sample Is 7% or less, and when the average value of the heat shrinkage ratios in the orthogonal direction is calculated, the heat shrinkage ratios in the orthogonal direction of all the samples are within ± 2% of this average value.

The heat-shrinkable polyester film roll satisfying all the above requirements (1) to (8) has a small compositional variation over the entire length of the film and a small variation in heat-shrinking behavior. Therefore, it has an excellent shrink finish, a shrink finish appearance with less shrinkage spots, wrinkles, and distortions can be obtained, and a beautiful gloss feeling and transparency can be obtained.

On the other hand, the heat-shrinkable polyester film roll of the present invention is based on the premise that the composition and the heat-shrinking behavior have small fluctuations by adopting the same method as the above-mentioned prior application. Further, the present invention has been made for the purpose of further reducing fluctuations in tear resistance. Less than,
The present invention will be described in detail.

First, the heat-shrinkable polyester film wound on the film roll of the present invention must satisfy the following requirement (A). (A) The winding start side end of the film in the steady region where the physical properties of the film are stable in the lengthwise direction of the film is the first end,
When the end portion on the winding end side is the second end portion, the first sample cutout portion is located within 2 m inside the second end portion.
Further, a final cutout portion is provided within 2 m inside the first end portion, and a sample cutout portion is provided about every 100 m from the first sample cutout portion.
A sample cut out in a square shape of × 10 cm was immersed in warm water of 85 ° C for 10 seconds and then pulled up, and then 1 minute in water of 25 ° C.
The thermal shrinkage in the maximum shrinkage direction when immersed in 0 seconds and pulled up is 20% or more for all the samples.

This requirement (A) is the requirement (1) of the above-mentioned prior application.
Is the same as. As a heat-shrinkable film, 2 at 85 ℃
Since it must be able to shrink by 0% or more, it was made an essential requirement.

The meaning of the above-mentioned requirement (A) "a steady region in which the physical properties of the film are stable in the longitudinal direction of the film" will be described. The "steady region in which the physical properties of the film are stable in the length direction of the film" is a region in which the film forming process and the stretching process are stably performed during film production, and the physical properties of the film are substantially uniform. In the present invention, in the long film obtained when the film forming step and the stretching step are operated in a stable steady state, it is possible to make the tear resistance and other properties highly uniform as compared with the conventional level. It is a technical idea. In actual operation, during film production, the composition of the film may vary depending on the raw material supply method and film forming conditions, but in the present invention, the film obtained when the raw material supply amount and film forming conditions are unstable It does not require uniformization. For this reason, it was assumed that the sampling when evaluating the characteristics requiring uniformization is performed only in the region where the film forming process and the stretching process are operated in a stable steady state, that is, in the “steady region”.

Therefore, for example, 1 from the beginning of winding the roll.
If the film is about 0 m when it is not in steady operation, do not sample from this part,
The 0th meter is sampled as the first end of the film.

The number of steady regions (steady operation region) is usually one per one film roll (one over the entire film roll). However, there may be multiple locations depending on the manufacturing situation, so
In this case, sampling is performed only from the steady region. The steady region can be evaluated, for example, by measuring the heat shrinkage ratio of the film in the maximum shrinkage direction by the method described below. That is, it can be considered that the region where the heat shrinkage is within about 20% (the difference between the maximum value and the minimum value of the heat shrinkage of a plurality of samples is within about 20%) is the steady region.

Next, a sampling method will be described.
Regarding the film wound on one roll, when the end on the winding start side of the film in the steady region is the first end and the end on the winding end side is the second end, the second end The first cutout portion is provided within 2 m of the inside of the above, and the final cutout portion is provided within 2 m of the inside from the above-mentioned first end portion, and the cutout portion of the sample is provided about every 100 m from the first cutout portion. By providing
Samples are selected at approximately equal intervals over the length of the constant region of the film. In addition, "about every 100m" means 100m
This means that the sample may be cut out at about ± 1 m.

The above sampling method will be described in more detail. For example, in the case where a heat-shrinkable film having a length of 498 m in a constant region is wound around a roll, the first sample is cut out within 2 m from the winding end (second end) of the film. . The area to be cut off is appropriately set according to the physical property value to be measured. Then, the second sample is cut out at a distance of about 100 m from the position where the first sample was cut out. Similarly, the third sample at about 200 m, the fourth sample at about 300 m, about 40
Cut out the fifth sample at 0 m. Where the rest is 1
Since the length is shorter than 00 m, the sixth (final) sample is cut off at any part within 2 m from the winding start (first end) of the film.

The requirement (A) of the present invention is that the heat shrinkage in the maximum shrinkage direction of all the samples thus cut is
It is more than 20%. When the heat shrinkage rate of the heat shrinkable polyester film is less than 20%, the heat shrinkage force of the film is insufficient, and when the container is covered and shrunk,
It is not preferable because it does not adhere to the container and a poor appearance occurs. The heat shrinkage rate is more preferably 40% or more, and further preferably 60% or more.

Here, the thermal contraction rate in the maximum contraction direction means the thermal contraction rate in the most contracted direction of the sample,
The maximum shrinkage direction is determined by the length of the cut square sample in the lengthwise direction or the widthwise direction. Also, heat shrinkage (%)
Is 10 cm × 10 cm sample immersed in warm water of 85 ° C. ± 0.5 ° C. for 10 seconds under no load condition to cause heat shrinkage, and then in 25 ° C. ± 0.5 ° C. water under no load condition. The length in the longitudinal and transverse directions of the film after being immersed for 10 seconds was measured, and the value was obtained according to the following formula (hereinafter, the heat shrinkage in the maximum shrinkage direction measured under these conditions is simply referred to as “heat shrinkage ratio”). "
Abbreviated). Heat shrinkage rate = 100 × (length before shrinkage−length after shrinkage) ÷
(Length before contraction)

Further, the film wound around the heat-shrinkable film roll of the present invention must have a breaking rate which is small over the entire length of the constant region of the film. That is, when a plurality of heat-shrinkable film test pieces selected under constant conditions were subjected to a tensile test under the conditions of a chuck distance of 100 mm, a test piece width of 15 mm, a temperature of 23 ° C. and a pulling speed of 200 mm / min, the breaking elongation was measured. The number of test pieces of 5% or less must be 10% or less of the total number of test pieces at each location at each location of the film from which the test specimen is collected. The test conditions are based on JIS K 7127.

The breaking rate is the same as in the measurement of the heat shrinkage rate for the film wound on one roll,
It is determined by selecting test pieces at substantially equal intervals over the entire length of the steady region of the film. Then, from each cut sample, the length in the direction orthogonal to the maximum contraction direction is 200 mm, and the width is 15 m.
A plurality of m test pieces are prepared and a tensile test is performed under the above conditions.
At this time, the number of test pieces having a breaking elongation of 5% or less is counted for each cutout portion, and this is taken as a percentage of the total number of test pieces for each cutout portion, and the above breakage rate is calculated.

The breakage rate specified in the present invention is, in other words,
This means that the number of test pieces that break before being stretched by 5% is 10% (10%) or less of the total number of test pieces at any of the test piece sampling locations (cutout portions). The smaller the number of test pieces having a breaking elongation of 5% or less, the better, the more preferable is 5% or less of the total number of test pieces, and the most preferable is 0%.

A film satisfying the above-mentioned conditions has the arrangement direction of the polymer molecules most easily split (that is, the maximum shrinkage direction).
Since it is excellent in tear resistance in the direction orthogonal to, it is possible to reduce loss due to breakage of the film during printing or tubing processing, and it is possible to perform high-speed processing.
Preferred means for reducing the fracture rate will be described later.

For the heat-shrinkable film roll of the present invention, a sample was prepared from the same location as each cut-out portion for measuring the heat-shrinkage rate and breakage rate, and the maximum heat-shrinkage stress value was measured according to the following method. At this time, the maximum heat shrinkage stress values of all the samples are 3.0 MPa or more, and when the average value of these maximum heat shrinkage stress values is calculated, the maximum heat shrinkage stress values of all the samples are ± of this average value. It is preferably within the range of 1.0 MPa or less. This requirement is the same as the requirement (7) of the prior application. The maximum heat shrinkage stress value is measured as follows.

(1) The length in the maximum shrinkage direction was 20 from each cutout portion in the above-mentioned measurement of the breaking rate of the heat-shrinkable film.
A test piece of 0 mm and a width of 20 mm is cut out.

(2) The inside of the heating furnace of a tensile tester (for example, "Tensilon" manufactured by Toyo Seiki) equipped with a hot air heating furnace
Heat to 0 ° C.

(3) Stop blowing air and set the test piece in the heating furnace. The distance between chucks is 100 mm (constant).

(4) The door of the heating furnace is promptly closed, and the blowing (the temperature of 90 ° C. and the blowing speed of 5 m / sec of hot air is supplied from the three directions of the back, left and right), and the heat shrinkage stress value is reached. To detect and measure.

(5) The maximum value is read from the chart and this is taken as the maximum heat shrinkage stress value (MPa).

Then, the average value of the maximum heat shrinkage stress values is calculated from the measurement result of the maximum heat shrinkage stress value of each of the cut test pieces. The maximum heat shrinkage stress value of the film is 3.0 MPa
When the amount is less than 1, the film has poor appearance due to insufficient shrinkage stress, and the film has insufficient mechanical strength, which causes a problem of deterioration of tear resistance, which is not preferable. A more preferable lower limit of the maximum heat shrinkage stress value is 3.5 MPa, and a further preferable lower limit thereof is 4.0 MPa.

Further, an average value is calculated from the maximum heat shrinkage stress values measured as described above, and the variation in the maximum heat shrinkage stress value of the long film is obtained. The average maximum heat shrinkage stress value is P
In (MPa), the maximum heat shrinkage stress value of the test piece (the test number corresponds to the sample number of each cutout portion described above in the test piece for measuring the heat shrinkage rate; the same applies hereinafter) is Q1 (MP.
a), | P-Q1 | (absolute value of P-Q1) is 1.0 MPa or less, and similarly in the maximum heat shrinkage stress values Q2 to Q6 (MPa) of the test pieces, | P
All -Qn | being 1.0 MPa or less means the average value of the maximum heat shrinkage stress values ± 1.0 MPa.
In other words, if both the difference between the maximum value Qmax and P of Qn and the difference between the minimum value Qmin and P are within ± 1.0 MPa, the preferable requirements of the present invention are satisfied.

When the fluctuation range of the maximum heat shrinkage stress value in the film roll is within an average value of ± 0.5 MPa or more and ± 1.0 MPa or less, the defective rate can be reduced by adjustment in the coating shrinkage step. it can. Further, when the variation of the maximum heat shrinkage stress value is less than the average value ± 0.5 MPa, no process adjustment is required, and a label, a bag or the like having a very excellent shrink finish is obtained. This variation in the maximum heat shrinkage stress value is more preferably within a range of the average value of the maximum heat shrinkage stress values ± 0.4 MPa.

The average value of the maximum heat shrinkage stress value itself is
It is preferably 4.0 MPa or more. If the average value of the maximum heat shrinkage stress value of the film is less than 4.0 MPa, a poor appearance of the film due to insufficient shrinkage stress of the film occurs, and a problem of deterioration of tear resistance occurs due to insufficient mechanical strength of the film. Not preferable. The average value of the maximum heat shrinkage stress values in the maximum shrinkage direction of the film according to the present invention is preferably 4.5 MPa or more, more preferably 5.0 MPa.
That is all.

The heat-shrinkable film is processed into a label or bag shape as described above, and then these are attached to a container, and a shrink tunnel (steam tunnel) of a type in which steam is blown to heat-shrink or hot air is applied. It is passed through an inside of a contraction tunnel (hot air tunnel) of blowing and heat-shrinking, and it is heat-shrinked and brought into close contact with the container.

In this heat-shrinking step, if the maximum heat-shrinkage stress value of each unit such as the label or bag has a large variation, the heating conditions in the tunnel are the same.
Labels and bags that do not show a certain maximum heat shrinkage stress value may occur, and these may cause poor appearance due to insufficient shrinkage, shrinkage spots, wrinkles, pattern distortion, label misalignment during shrinkage, vertical sinking, etc. As a result, it may not be possible to make the final product. Usually, the same final product label, bag, etc. are processed from one film roll,
When the maximum heat shrinkage stress value of the film wound on one film roll varies greatly, there is a problem that the defective rate in such a heat shrinkage step increases.

However, by reducing the fluctuation of the maximum heat shrinkage stress value of one heat-shrinkable film roll as described above, the fluctuation of the maximum heat shrinkage stress value of one, one label, bag, etc. Since the size becomes smaller, defects in the process of shrinking the coating can be reduced, and the defective rate of the product can be drastically reduced.
Further, if the film roll satisfies the requirement of the fluctuation range of the maximum heat shrinkage stress value, the requirement (1) of the above-mentioned prior application.
It can be said that all of (8) are satisfied.

Next, a preferable method for producing a long film showing a uniform fracture rate over the entire length will be described. The heat-shrinkable polyester film roll of the present invention comprises a single copolymerized polyester having a known polyvalent carboxylic acid component and an ester unit formed from a polyhydric alcohol component as a main constituent unit, or two or more polyesters. A film roll obtained by winding a heat-shrinkable polyester film obtained by using a mixture.

The film constituting the heat-shrinkable polyester film roll is required to have a raw material polymer containing one or more secondary constitutional units different from the main constitutional unit. This is because the fluctuation of the rupture rate (breaking resistance) is composed of a main constituent unit of crystallinity in which the heat-shrinkable polyester film bears strength and heat resistance and one or more secondary constituent units responsible for heat-shrinkability. This is because it is noticeable in some cases, and at the same time, in order to exhibit good heat shrinkage characteristics, a secondary constituent unit for increasing the amorphousness is necessary. And
When such a raw material polyester is extruded into a film in accordance with the melting temperature of the crystal part of the main constituent unit, the secondary constituent unit having lower heat resistance than the main constituent unit undergoes heat history during melt extrusion, resulting in heat Causes decomposition and hydrolysis. The present invention is intended to reduce the variation of the breaking rate in the film roll by reducing the thermal decomposition and hydrolysis, the raw material polyester of the present invention is a main constituent unit Required that it include one or more other secondary constituent units.

Specifically, the tear resistance, strength, and
In consideration of heat resistance and the like, it is preferable to use a crystalline ethylene terephthalate unit composed of ethylene glycol and terephthalic acid (or dimethyl ester) as the main constituent unit, and the ethylene terephthalate unit is 50 mol% in 100 mol% of the constituent unit. It is recommended to select the above. The ethylene terephthalate unit is more preferably 55 mol% or more, 60
More preferably, it is at least mol%. However, if the amount of the secondary constituent unit is reduced, the heat shrinkage property is deteriorated.
It is preferably 0 mol% or less, more preferably 70 mol% or less.

Then, at least one of a unit consisting of 1,4-cyclohexanedimethanol and terephthalic acid, a unit consisting of neopentyl glycol and terephthalic acid, and a unit consisting of 1,4-butanediol and terephthalic acid is added as a sub-component. It is preferably used as a secondary constituent unit. The unit composed of 1,4-cyclohexanedimethanol and terephthalic acid and the unit composed of neopentyl glycol and terephthalic acid increase the degree of amorphization of polyester, and increase the heat shrinkage rate and the maximum heat shrinkage stress value.
Further, the unit composed of 1,4-butanediol and terephthalic acid lowers the Tg of the polyester as a whole, and is effective for exhibiting heat shrinkability at low temperatures. It is desirable that the total amount of these secondary constituent units is 100 mol% or more, 5 mol% or more, preferably 10 mol% or more, and more preferably 15 mol% or more. By introducing the amorphousness improving component, it becomes possible to secure solvent adhesion and heat shrinkability of the film.

Further, the raw material polyester of the polyester film of the present invention may further contain another unit. Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, and 5-sodium sulfoisophthalic acid as a polyvalent carboxylic acid component constituting another unit;
Aliphatic dicarboxylic acids such as dimer acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid and succinic acid; derivatives of these dialkyl esters, diaryl esters, acid halides and the like can be mentioned. Other, p
-An oxycarboxylic acid such as oxybenzoic acid or a polyvalent carboxylic acid such as trimellitic anhydride or pyromellitic dianhydride may be used in combination as necessary.

As the polyhydric alcohol component for constituting another unit, ethylene glycol, diethylene glycol, dimer diol, 1,3-propanediol, triethylene glycol, 1,4-butanediol, neopentyl glycol, 1, 4-cyclohexanedimethanol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1, Alkylene glycols such as 9-nonanediol and 1,10-decanediol, alkylene oxide adducts of bisphenol compounds or their derivatives,
Examples include trimethylolpropane, glycerin, pentaerythritol, polyoxytetramethylene glycol, polyethylene glycol and the like.

Although not polyhydric alcohols, ε-
Some lactones represented by caprolactone may also be used. Lactones are units that are opened to become units having ester bonds at both ends, and one lactone-derived unit can be considered to be a carboxylic acid component and an alcohol component. Therefore, when lactones are used, the amount of each polyhydric alcohol component is calculated by adding 100 mol% to the total amount of polyhydric alcohol components of the film and the amount of the unit derived from the lactone. Also,
Also when obtaining the amount of each polyvalent carboxylic acid component, the total amount of the polyvalent carboxylic acid component of the film plus the unit amount derived from the lactone is calculated as 100 mol%.

As a method of incorporating a secondary constituent unit other than the main constituent unit into the film, a method of copolymerizing and using this copolymer alone, and a method of using a different kind of homopolypolymer or copolymer There is a method of blending, but in the blending method, the physical properties of the film can be easily changed just by changing the blend ratio, and it can be used for industrial production of various types of film,
Industrially preferable.

Polyester can be produced by melt polymerization by a conventional method, but dicarboxylic acids and glycols are directly reacted to polycondense the obtained oligomer,
Examples include so-called direct polymerization method, so-called transesterification method in which dimethyl ester of dicarboxylic acid and glycol are subjected to transesterification reaction and then polycondensation, and any production method can be applied. Further, it may be a polyester obtained by another polymerization method. The unit derived from a lactone can be introduced by, for example, a method of adding a lactone before the above polycondensation to carry out polycondensation, or a polymer obtained by the above polycondensation and a polycondensation by adding a lactone. Can be achieved by a method such as

In order to prevent inconveniences such as coloring and gel formation, the polyester contains, in addition to polymerization catalysts such as antimony oxide, germanium oxide and titanium compounds, magnesium salts such as magnesium acetate and magnesium chloride, calcium acetate, Ca salts such as calcium chloride, manganese acetate,
Mn salts such as manganese chloride, Zn such as zinc chloride and zinc acetate
Cobalt such as salt, cobalt chloride, cobalt acetate, etc. is added to the polyester as metal ion of 300 ppm, respectively.
(Mass basis, the same applies hereinafter) Phosphoric acid or phosphoric acid ester derivatives such as phosphoric acid trimethyl ester and phosphoric acid triethyl ester may be added in an amount of 200 ppm or less in terms of phosphorus (P).

The total amount of metal ions other than the above polymerization catalyst was 300 ppm with respect to polyester, and the P amount was 200 pp.
When it exceeds m, not only the coloring of the polymer becomes remarkable, but
It is not preferable because the heat resistance and the hydrolysis resistance of the polymer are remarkably lowered and the tear resistance is lowered.

At this time, in terms of heat resistance, hydrolysis resistance, etc., the mass ratio (P / M) of the total amount of P (P) and the total amount of metal ions (M) is 0.4 to 1.0. Is preferred.
If the mass ratio (P / M) is less than 0.4 or exceeds 1.0, the film may be colored or coarse particles may be mixed into the film, which is not preferable.

The timing of adding the above metal ions and phosphoric acid and its derivatives is not particularly limited. Generally, the metal ions are charged at the time of charging the raw materials, that is, before transesterification or esterification, and the phosphoric acids are subjected to a polycondensation reaction. It is preferably added before. If necessary, fine particles of silica, titanium dioxide, kaolin, calcium carbonate, etc., an ultraviolet absorber, an antistatic agent, a coloring agent, an antibacterial agent, etc. may be added.

In order to prevent thermal decomposition or hydrolysis reaction during or after the polymerization or during the melt extrusion described later, it is preferable to add an antioxidant, an ultraviolet stabilizer or the like. As the antioxidant, a phenol-based or amine-based compound, a primary antioxidant having a radical scavenging or chain-terminating action, and a phosphorus-based or sulfur-based compound,
A secondary antioxidant having a peroxide decomposing action can be mentioned,
Any of these can be used.

Specific examples of the above antioxidants include phenolic antioxidants such as phenols, bisphenols, thiobisphenols and polyphenols; amine antioxidants such as diphenylamines and quinolines; phosphites, Examples include phosphorus-based antioxidants such as phosphonite; sulfur-based antioxidants such as thiodipropionate.

A more specific compound is n-octadecyl-β- (4'-hydroxy-3,5'-di-t-.
Butylphenyl) propionate, tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] (This compound is available from Ciba Specialty Chemicals under the trade name "Irganox 1010". Commercially available), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-tris (3,5-di-t)
-Butyl-4-hydroxybenzyl) -S-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,
3,5-Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (This compound is commercially available from Ciba Specialty Chemicals, Inc. under the trade name "Irganox 1330". , Tris (mixed mono and / or dinonylphenyl) phosphite, cyclic neopentatetraylbis (octadecyl phosphite) (this compound is commercially available from Asahi Denka under the trade name “PEP-36”). , Tris (2,4-di-t-butylphenylphosphite), 2,2-methylenebis (4,6-di-).
t-butylphenyl) octyl phosphite), dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate and the like.

These antioxidants may be used alone or in combination of two or more. The primary antioxidant and the secondary antioxidant can be used in combination. Of these, antioxidants that suppress secondary oxidation are preferable, and phosphorus compounds are particularly preferable. The preferred amount of the antioxidant used is 0.01 to 1% by mass in the extrusion raw material composition.

After the polyester is polymerized, it is preferable to make chips by a known strand cutter or the like. At this time,
In order to prevent the raw material segregation and reduce the composition variation, it is necessary to adopt the above-mentioned chip shape equalizing means as the composition variation suppressing means.

After the chips are manufactured, it is preferable to remove water that affects the hydrolyzability as much as possible and store the chips. When the chips are dried, a known method such as using dehumidified air at a temperature that does not cause thermal decomposition can be used. The water content of the chips is preferably 100 ppm or less, 50 pp
m is more preferred.

To produce a film, the above raw material chips are sufficiently dried using a dryer such as a hopper dryer, a paddle dryer or a vacuum dryer to obtain 200 to 300.
Extruded into a film at a temperature of ℃. Alternatively, the undried polyester raw material chips may be similarly extruded into a film shape while removing water in a vent type extruder. The water content at this time is also preferably 100 ppm or less, 50 pp
m is more preferred. Further, in the extrusion step, any one or more of the above composition variation suppressing means, preferably all means are employed.

In the extrusion step, it is preferable to consider the decrease in the intrinsic viscosity of the polyester due to thermal decomposition, hydrolysis or the like. If the intrinsic viscosity is too low, the molecular weight of the polyester that constitutes the film will be low, and the shrinkage stress during heat shrinking will decrease rapidly as the shrinkage time elapses. This is because the disadvantage of (1) is not improved even after a lapse of time, resulting in poor shrink finish and appearance. Further, a decrease in the molecular weight of the polyester lowers the mechanical strength and tear resistance of the film, causes a deterioration of the breaking rate, and causes a change in the breaking rate.

From this point of view, the intrinsic viscosity of the polyester (raw polyester) before extrusion is 0.5 to 1.3 d.
XY in the range of 1 / g and between the intrinsic viscosity X of the raw material polyester and the intrinsic viscosity Y of the obtained film
However, it is preferable to control the film to be 0.08 dl / g or less to produce a film. The more preferable lower limit of the intrinsic viscosity of the raw material polyester is 0.6 dl / g, the more preferable upper limit thereof is 1.2 dl / g, and the more preferable upper limit of XY is 0.05 dl / g.

In order to suppress the decrease of the intrinsic viscosity in the melt extrusion step, in addition to the above-mentioned means of blending the antioxidant, the ultraviolet stabilizer, etc., and reducing the water content of the chips, an appropriate melting temperature is used. It is recommended to extrude the film, to adopt an extrusion equipment having a structure that does not cause convection in the extruder, the T-die, and the path between them. The intrinsic viscosity of the polyester specified in the present invention is a value measured by the method used in Examples described later.

For extrusion, any existing method such as T-die method or tubular method may be adopted. After extrusion,
Cool on a casting roll to obtain an unstretched film. The "unstretched film" also includes a film to which a tension necessary for feeding the film in the manufacturing process is applied.

The unstretched film is stretched. The stretching treatment may be performed continuously after cooling with the casting roll or the like, or may be performed after cooling and once wound on a roll.

In the heat-shrinkable film roll of the present invention, it is practical in terms of production efficiency that the maximum shrinkage direction is the film lateral (width) direction. An example of the stretching method will be shown. Even when the maximum shrinkage direction is the longitudinal (longitudinal) direction of the film, the stretching can be carried out according to a normal operation such as changing the stretching direction by 90 ° in the following method.

Further, focusing on making the thickness distribution of the heat-shrinkable polyester film uniform, it is preferable to carry out a preliminary heating step prior to the stretching step when stretching in the transverse direction using a tenter or the like. In this preheating step, the heat transfer coefficient is 0.00544 J / cm ² · sec ·
℃ (0.0013 calories / cm ² · sec · ° C) or less, low wind speed and film surface temperature Tg + 0
It is preferable to perform heating to a certain temperature within the range of ℃ to Tg + 60 ℃.

The stretching in the transverse direction is Tg-20 ° C. to Tg + 4.
At a predetermined temperature within the range of 0 ° C., the film is stretched 2.3 to 7.3 times, preferably 2.5 to 6.0 times. Then 60 ℃ ~ 1
Heat treatment is performed at a predetermined temperature in the range of 10 ° C while stretching 0 to 15% or relaxation of 0 to 15%, and if necessary, further heat treatment is performed at a predetermined temperature in the range of 40 ° C to 100 ° C. A heat-shrinkable polyester film is obtained. In this transverse stretching step, the means for reducing the fluctuation of the film surface temperature described after [Composition fluctuation suppressing means] should be adopted.

As a stretching method, not only transverse uniaxial stretching with a tenter but also longitudinal stretching of 1.0 to 4.0 times, preferably 1.1 to 2.0 times may be performed. Good. When biaxial stretching is performed in this way, either sequential biaxial stretching or simultaneous biaxial stretching may be performed, and re-stretching may be performed as necessary. Further, in the sequential biaxial stretching, the stretching order may be any of vertical and horizontal, horizontal and vertical, vertical and horizontal vertical, horizontal and vertical, and the like. Even when these longitudinal stretching step or biaxial stretching step is adopted, the fluctuation of the film surface temperature must be minimized in the preliminary heating step, the stretching step, etc., as in the case of transverse stretching.

The internal heat generation of the film due to stretching is suppressed,
Focusing on the point of reducing the film temperature unevenness in the width direction,
The heat transfer coefficient in the drawing process is 0.00377 J / cm ² ·
sec ・ ° C (0.0009 calories / cm ²・ sec ・
C.) or higher is preferable. 0.00544-0.
00837 J / cm ² · sec · ° C (0.0013 ~
0.0020 calories / cm ² · sec · ° C) is more preferable.

The heat-shrinkable film roll of the present invention is preferably a heat-shrinkable film having a width of 0.2 m or more and a length of 300 m or more wound around a winding core. Film rolls less than 0.2m wide
It is industrially low in value and has a length of 300.
A film roll having a length of less than m has a small winding length of the film, and thus the variation of the breaking rate and the maximum heat shrinkage stress value over the entire length of the film is small, and thus the effect of the present invention is difficult to be exhibited. The width of the heat-shrinkable film roll is 0.3m
The above is more preferable, and 0.4 m or more is further preferable.
The length of the heat-shrinkable film wound on the roll is 4
00 m or more is more preferable, and 500 m or more is further preferable.

The upper limits of the width and winding length of the film roll are not particularly limited, but for ease of handling,
Generally, the width is 1.5m or less, and the roll length is film thickness 45μ.
In the case of m, it is preferably 6000 m or less. Further, as the winding core, a paper tube, a plastic core or a metal core having a size of 3 inches, 6 inches, 8 inches or the like can be usually used.

The thickness of the film constituting the heat-shrinkable film roll of the present invention is not particularly limited. For example, as the heat-shrinkable film for labels,
200 μm is preferable, and 20 to 100 μm is more preferable.

The heat-shrinkable polyester film roll of the present invention is used, for example, in the production of labels, and in this case, it is preferable to use a solvent for adhesion. Adhesive solvents include aromatic hydrocarbons such as benzene, toluene, xylene and trimethylbenzene; halogenated hydrocarbons such as methylene chloride and chloroform; phenols such as phenols; furans such as tetrahydrofuran;
Organic solvents such as oxolanes such as 1,3-dioxolane; Among them, 1,3 in terms of high safety
-Dioxolane is preferred.

[0085]

The present invention will be described in more detail with reference to the following examples, but the following examples are not intended to limit the present invention, and any modifications made within the scope of the present invention are included in the present invention. Be done. The methods for measuring the physical properties of the chips obtained in the synthesis examples and the films obtained in the examples and comparative examples are as follows.

(1) Precisely weigh 0.1 g of an intrinsic viscosity sample (chip or film), and
After dissolving in 3 ml of a mixed solvent of phenol / tetrachloroethane = 3/2 (mass ratio), 3 with an Ostwald viscometer
Measure at 0 ± 0.1 ° C. The intrinsic viscosity [η] is calculated by the following formula (H
uggins equation).

[0087]

[Equation 1]

Here, η _{sp is the} specific viscosity, t _{0 is} the dropping time of the solvent using the Ostwald viscometer, t is the dropping time of the film solution using the Oswald viscometer, and C is the concentration of the film solution.

In the actual measurement, the intrinsic viscosity was calculated according to the following approximate equation where k = 0.375 in the Huggins equation.

[0090]

[Equation 2]

Here, η _r is the relative viscosity.

(2) Confirmation of steady region The steady region of the film wound on the film roll was confirmed as follows. Five sample cutouts are provided every 20 m from the position 0 m from the end of winding of the film, and five sample cutouts are provided every 20 m from the position 100 m from the start of winding to the inside (winding end direction). From each sample cutout portion, the film was cut into a square of 10 cm × 10 cm along the running direction and the direction orthogonal thereto to prepare a test piece. 85 each test piece
After immersing in warm water of ℃ ± 0.5 ℃ for 10 seconds under no load condition to cause heat shrinkage, and then immersing in water of 25 ℃ ± 0.5 ℃ for 10 seconds, lengthwise and transverse length of the sample Was measured, and the heat shrinkage rate was determined according to the following formula. Thermal shrinkage rate (%) = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage)

In all of the film rolls described below produced in the examples and comparative examples, the heat shrinkage ratio in the maximum shrinkage direction of all the test pieces was within the width of 20% (that is, all the film rolls were The difference between the maximum and minimum values of heat shrinkage is 2
It was 0% or less). Furthermore, the conditions of the film forming step and the stretching step were stable over the entire region from the beginning to the end of winding of the film. Therefore, in all of the films wound on the film rolls described below, which were produced in the examples and comparative examples, the entire region corresponds to the steady region.

(3) Heat Shrinkage Ratio The average value of the heat shrinkage ratios obtained in the above-mentioned confirmation of the steady region is shown.

(4) Rupture resistance (breakage rate) According to JIS K 7127, a tensile test was carried out in the direction orthogonal to the maximum shrinkage direction of the film before heat treatment. Test piece length 200 mm, chuck distance 100 m
m, test piece width 15 mm, temperature 23 ° C., pulling speed 200 m
It carried out on condition of m / min. The number of test pieces that broke at an elongation of 5% or less was counted, and the percentage with respect to the total number of test pieces (20 pieces) was determined and used as the rupture rate.

Sampling method: The first sample cut-out portion is the winding end portion (0 from the winding end) of the film.
m). The final cutout portion was the winding start portion of the film (0 m from the winding start), and 11 samples were cut out in total. Note that 20 test pieces were cut out from each of the sample cutout portions. For the breakage rate in Table 2 described later, the maximum breakage rate among the measurement results of the cutout portions was shown.

(5) Maximum heat shrinkage stress value Using a tensile tester with a heating furnace ("Tensilon" manufactured by Toyo Seiki Co., Ltd.), a heat shrinkable film roll was sampled by a sampling method described below, and the length in the maximum shrinkage direction was 200 mm. Then, a sample with a width of 20 mm was cut out, the air flow in a heating furnace preheated to 90 ° C. was stopped, and the sample was attached to the chuck at positions of 50 mm from both ends of the sample so that the chuck-to-chuck distance became 100 mm. Close the heating furnace door and blow air (temperature 90 ° C, blowing speed 5m
/ Second hot air is supplied from three directions of back, left and right), and the detected shrinkage stress was measured, and the maximum value obtained from the chart was defined as the maximum heat shrinkage stress value (MPa). Similarly to the case of the fracture rate of (3), the maximum heat shrinkage stress value was measured for the samples cut out from the 11 sample cutout portions in total, and the average value of the maximum heat shrinkage stress values was obtained.

In Table 2 described later, the average value (P) is the average value of the maximum heat shrinkage stress values of all the 11 samples measured, and the maximum value (Qmax) is the maximum value of the maximum heat shrinkage stress values of the 11 samples. The minimum value (Qmin) indicates the minimum maximum heat shrinkage stress value among the 11 samples, and the difference from the average value is also shown.

(6) Shrinkage Finishing Property The entire length of the film wound on the heat-shrinkable film roll is printed with three colors of grass-colored, gold-colored, and white ink manufactured by Toyo Ink Mfg. Co., and the film is slit and then Using a center seal machine, 1,3-dioxolane was solvent-bonded to form a tube, which was wound in two folded states.

This tube was cut to an appropriate length to prepare a heat-shrinkable film label, and a steam tunnel (model: SH-1500-L) manufactured by Fuji Astec Co. was used to make a 1.5 L PET bottle. On the other hand, a heat-shrinkable film label is attached, and the entire amount of the prepared label is passed under the condition of tunnel passage time of 10 seconds, 1 zone temperature / 2 zone temperature = 80 ° C / 90 ° C, and the shrinkage finish is visually judged. did. The shrinkage finish is evaluated by the following five-stage evaluation,
5: Best finish, 4: Good finish, 3: Some defects (within 2 places), 2: Defects (3 to 5 places),
1: There were many defects (6 or more places), 4 or more were judged as pass level, and 3 or less were judged as defective, and the shrinkage finish defective rate (%) was obtained according to the following formula. The drawback here is
There are wrinkles, folds in the label edges, color spots, and insufficient shrinkage. Shrinkage finish defect rate = 100 x number of defective samples / total number of samples

(7) Number of breaks during printing (times) The number of breaks per 1000 m of the printed film roll was measured by the same method as the above-mentioned evaluation of shrink finish.

(8) Surface Temperature of Film The surface temperature of the film in the preheating step, the stretching step, and the heat treatment step after stretching is continuously measured in the running direction of the film using an infrared non-contact surface thermometer. Then, the average value of the temperatures obtained in each step was obtained.

Synthesis Example 1 (Synthesis of Polyester) In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux type cooler, 100 mol% of dimethyl terephthalate (DMT) was used as a dicarboxylic acid component (polycarboxylic acid component). And ethylene glycol (EG) 72 as a glycol component (polyhydric alcohol component)
Mol% and neopentyl glycol (NPG) 28 mol%
Was added so that the molar ratio of glycol was 2.2 times that of methyl ester, zinc acetate was 0.05 mol% (based on the acid component) as a transesterification catalyst, and antimony trioxide (0.1%) was used as a polycondensation catalyst. 025 mol% (based on the acid component) was added, and the transesterification reaction was performed while distilling off the produced methanol to the outside of the system. Then, at 280 ° C. 26.
Polycondensation reaction was performed under a reduced pressure condition of 7 Pa to obtain polyester A having an intrinsic viscosity of 0.70 dl / g.

After polymerization, the material was taken out in a molten state in a strand form from the polymerization apparatus, immediately cooled with water, and then cut with a strand cutter to obtain a raw material chip A. In addition, the cutting conditions were changed to create slightly smaller chips. This is a raw material chip B.

Synthesis Examples 2 to 4 By the same method as in Synthesis Example 1, polyester raw material chips C to E shown in Table 1 were obtained. In Table 1, BD is 1,4-butanediol, EG is ethylene glycol, CHDM
Means 1,4-cyclohexanedimethanol, respectively. The intrinsic viscosity of each polyester is
Chip C is 0.68 dl / g, Chip D is 0.73 dl
/ G, and the chip E was 1.20 dl / g.

[0106]

[Table 1]

Example 1 Each chip obtained in the above synthesis example was separately predried.
Moisture content of each chip (measured by Karl Fischer moisture meter)
Is as shown in Table 1. The water content of the chip A used in Example 1 was 78 ppm (200 in the table).
ppm is the value when the drying was insufficient in Comparative Example 2). As shown in Table 1, while 70 mass% of the chip A, 5 mass% of the chip D, and 25 mass% of the chip E are continuously and separately supplied to the hopper directly above the extruder with a constant-volume screw feeder. , Mixed in this hopper. Also,
With another feeder, the antioxidant "PEP-" manufactured by Asahi Denka Co., Ltd.
36 "was supplied so that it might be 0.2 mass%.

Subsequently, polyester was melt-extruded at 280 ° C. by a single-screw extruder and then rapidly cooled to a thickness of 180 μm.
An unstretched film of was obtained. The hopper has 15 raw chips
It has a capacity of 0 kg and the discharge rate of the extruder is 450 kg per hour. The inclination angle of the hopper is 7
It was 0 °.

The above unstretched film was preheated at 100 ° C. for 10 seconds, then stretched in the transverse direction at 80 ° C. by 4.0 times in a transverse direction, and then heat treated at 80 ° C. for 10 seconds to give a thickness of 45.
A μm heat-shrinkable polyester film was continuously formed over 1000 m or more. The fluctuation range of the film surface temperature when the film is continuously manufactured for 1000 m is the average temperature ± 0.5 ° C. in the preheating step and the average temperature ± 0.5 in the stretching step.
The average temperature was ± 0.5 ° C in the heat treatment step. The obtained film was slit into a width of 0.4 m and a length of 1000 m and wound on a 3-inch paper tube to obtain a heat-shrinkable film roll. Table 2 shows the physical properties of the film of the obtained film roll. The “theoretical value of the intrinsic viscosity of the film” in Table 2 is a value calculated by the following formula from the melt viscosity of each chip used in the production of the film and the mass fraction of each chip. [Theoretical value of melt _{viscosity] = η 1 × (W 1} /100) + η 2 ×
(W ₂ /100)+...+η _n × (W _n / 100)

Here, η _i is the intrinsic viscosity of the chip i used for manufacturing a film, and W _i is the percentage (%) of the amount of the chip i used. By the way, in the film of Example 1, 0.70 × (70/100) + 0.73 × (5/1
00) + 1.20 × (25/100) = 0.83.

Example 2 Each of the chips obtained in the above synthesis example was pre-dried separately, and as shown in Table 1, chip C was 62% by mass, chip D was 18% by mass and chip E was 20% by mass. Were continuously and separately fed to the hopper directly above the extruder with a metering screw feeder, and mixed in this hopper. Further, 0.15% by mass of the above-mentioned "PEP-36" and 0.15% by mass of "IRGANOX 1010" manufactured by Ciba Specialty Chemicals Co., Ltd. were supplied and mixed in another feeder. The film raw material was melt-extruded at 280 ° C. by a single-screw extruder and then rapidly cooled to obtain an unstretched film having a thickness of 180 μm. The hopper has a capacity of 100 kg of raw material chips, and the discharge amount of the extruder is 450 kg per hour. The inclination angle of the hopper was 75 °.

After preheating the above unstretched film at 80 ° C. for 10 seconds, it was stretched in the transverse direction at a temperature of 72 ° C. by 4.0 times with a tenter, and then heat treated at 76 ° C. for 10 seconds to give a thickness of 45.
A μm heat-shrinkable polyester film was continuously formed over 1000 m or more. The fluctuation range of the film surface temperature when the film is continuously manufactured for 1000 m is an average temperature ± 0.8 ° C. in the preheating step and an average temperature ± 0.5 in the stretching step.
The average temperature was ± 0.6 ° C in the heat treatment step. The obtained film was slit into a width of 0.4 m and a length of 1000 m and wound on a 3-inch paper tube to obtain a heat-shrinkable film roll. Table 2 shows the physical properties of the film of the obtained film roll.

Comparative Example 1 The composition shown in Table 1, that is, 70% by mass of Chip B,
Extruding, film-forming and stretching steps were carried out in the same manner as in Example 1 except that 5% by mass of chip D and 25% by mass of chip E were used, and that no antioxidant was added. Got The water content of each chip after the preliminary drying is as shown in Table 1. It can be seen that the chip B was not sufficiently dried. Table 2 shows the physical properties of the film of the obtained film roll.

Comparative Example 2 A heat-shrinkable film roll was obtained by carrying out the extrusion, film formation and stretching steps in the same manner as in Example 1 except that no antioxidant was added. However, the water content of each chip after preliminary drying was as shown in Table 1, and the water content of 200 ppm was different from that of Example 1 due to insufficient drying of the chip A. The physical property values of the film of the obtained film roll are shown in Table 2.
Shown in.

[0115]

[Table 2]

As is clear from Table 2, in Examples 1 and 2 in which the chips were sufficiently dried and an antioxidant was also incorporated, both the breakage rate and the number of breaks during printing were good. On the other hand, in Comparative Examples 1 and 2 in which the chips were not sufficiently dried and the antioxidant was not mixed, the heat shrinkage characteristics were good with no variations as in the case of the Examples, but the breakage rate and the number of breaks during printing Is clearly inferior to the examples.

[0117]

EFFECTS OF THE INVENTION The heat-shrinkable film roll of the present invention is less likely to cause breakage troubles in the processing step because the variation of the breaking rate of the long film wound around the film roll is small, and further the maximum heat shrinkage stress. Since the variation of the value is small, the occurrence of defects due to insufficient shrinkage, shrinkage unevenness, wrinkles, distortion, vertical shrinkage, etc. in the heat shrinking process is extremely small. In addition, the method for producing a heat-shrinkable film roll of the present invention is very useful in industrial production, because a long film having excellent processability can be easily obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) C08L 67:02 C08L 67:02 (72) Inventor Yoshinori Takekawa 2-1-1 Katata, Otsu, Shiga Prefecture Toyobo Katsuya Ito, Inventor Katsuya Ito 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd. (72) Inventor Shigeru Yoneda 2-8 Dojimahama, Kita-ku, Osaka Toyobo Achievement in-house Co., Ltd. (72) Inventor Katsuhiko Nose 2-8 Dojimahama, Kita-ku, Osaka Toyobo Co., Ltd. In-house F-term (reference) 4F071 AA43 AA46 AA88 AF14 AF61 AH04 BC01 4F210 AA24 AE01 AG01 AH54 AR06 AR12 QA02 QC03 QD25 QG01 QG18 QL16 QL17 QW05 RA03 RC02 RG02 RG04 RG43

Claims (6)

[Claims] 1. A film roll obtained by winding a heat-shrinkable polyester film, wherein the raw material polymer of the heat-shrinkable polyester film has a secondary constituent unit different from the main constituent unit. The first end is the end of the film on the winding start side in the steady region where the physical properties of the film are stable in the length direction of the film.
When the end portion on the winding end side is the second end portion, the first sample cutout portion is also provided within 2 m inside the second end portion,
A final cutout was provided within 2 m inside the first end, and a sample cutout was provided about every 100 m from the first sample cutout, and a 10 cm × 10 cm square was cut out from each sample cutout. 8 samples
Immerse in warm water at 5 ℃ for 10 seconds and pull up, then at 25 ℃
The heat shrinkage ratio in the maximum shrinkage direction when immersed in water for 10 seconds and pulled up is 20% or more for all the samples, and a plurality of heat shrinkable film test pieces separately cut out from each sample cutout part are prepared. Then, for the test piece, a tensile test in a direction orthogonal to the maximum shrinkage direction of the film was conducted. A distance between chucks was 100 mm, a width of the test piece was 15 mm, and a temperature was 23.
When the test piece was cut out at a temperature of 200 ° C. and a tensile speed of 200 mm / min, the number of test pieces having a breaking elongation of 5% or less in each sample cutout portion was 10% or less of the total number of test pieces in each sample cutout portion. Characteristic heat-shrinkable polyester film roll. 2. The main constituent unit is an ethylene terephthalate unit, and the subsidiary constituent unit is a unit consisting of neopentyl glycol and terephthalic acid, a unit consisting of 1,4-cyclohexanedimethanol and terephthalic acid, 1. The heat-shrinkable polyester film roll according to claim 1, wherein the heat-shrinkable polyester film roll is at least one unit selected from 4-butanediol and terephthalic acid. 3. The maximum heat shrinkage stress value in the maximum shrinkage direction of each sample cut out from each of the sample cutout portions is measured in hot air at a temperature of 90 ° C. and a blowing speed of 5 m / sec, a sample width of 20 mm, and a gap between chucks. When measured under the condition of a distance of 100 mm, the maximum heat shrinkage stress values of all the samples are 3.
It is 0 MPa or more, and when the average value of these maximum heat shrinkage stress values is calculated, the maximum heat shrinkage stress values of all the samples are within the range of ± 1.0 MPa of this average value. The heat-shrinkable polyester film roll according to 2. 4. The heat-shrinkable polyester film roll according to claim 1, wherein a heat-shrinkable polyester film having a width of 0.2 m or more and a length of 300 m or more is wound up. 5. A method for producing a heat-shrinkable polyester film roll according to claim 1, wherein
The intrinsic viscosity of the raw material polyester is 0.5 to 1.3 dl /
g and the intrinsic viscosity X of the raw material polyester
And the difference XY between the obtained film and the intrinsic viscosity Y is
A method for producing a heat-shrinkable polyester film roll, which is controlled to be 0.08 dl / g or less. 6. The production method according to claim 5, wherein polyester having a water content of 100 ppm or less is used as a raw material.