JP2003211539A - Manufacturing method for heat-shrinkable polyester tube and heat-shrinkable polyester tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a manufacturing method for a heat-shrinkable polyester tube, which is excellent in energy efficiency and by which either ununiform width or ununiform stretching hardly develop, and the tube manufactured thereby. <P>SOLUTION: In order to manufacture the heat-shrinkable polyester tube, a copolymer polyester including inorganic fine particles and a polyolefin elastomer is tubularly extruded and then taken up with pinch rollers 1 in the hot water of 95 to 100°C so as to tubularly-stretch and expand the tube 3 passed through the pinch rollers 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a heat-shrinkable polyester tube and a heat-shrinkable polyester tube.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a heat-shrinkable polyester tube, a molten polyester material is extruded through a ring-shaped die, and is drawn by a pinch roller in an unstretched state and passed through a pinch roller. A manufacturing method of heating and stretching is adopted. The manufacturing process when this manufacturing method is adopted is shown in FIG.

As shown in the figure, a cooling tank 60 is provided between the ring-shaped die 4 and the pinch roller 1, and the temperature of the cooling tank 60 is maintained at about room temperature (30 ° C. or lower). As a result, the unstretched state of the material is substantially ensured at the portion of the pinch roller 1, and problems such as adhesion at this portion or thereafter are avoided.

[0004]

Without such intermediate cooling, the material from the extruder reaches the pinch rollers while being sequentially cooled, and then the tube is stretched by the method of polyvinyl chloride (PVC). Has been adopted by. PVC has the property of being less sticky than polyester resin. Therefore, in PVC, the cooling tank 60
The material temperature of the portion where is disposed may be relatively high as 85 to 100 ° C. In addition, since PVC itself easily separates between the films in this way, its behavior is stable even when a relatively high pressure is applied during the tubular stretching. Therefore, wall thickness and width unevenness are less likely to occur in the longitudinal direction that is the take-up direction.

However, in the case of polyester resin,
The material properties are different, and in tube molding, the inner surfaces tend to stick to each other, and stretching tends to be unstable. Therefore, if the tubular drawing is carried out without intermediate cooling, the wall thickness / width unevenness is likely to occur at an extension of about 50 m, which is not practical.

Further, the method involving such intermediate cooling, which is adopted for polyester, is wasteful in terms of energy because it is cooled and then heated to perform the tubular stretching.

An object of the present invention is to produce a copolyester tube which is obtained by melt extrusion and then tubular drawing.
Another object of the present invention is to obtain a method for producing a heat-shrinkable polyester tube in which uneven width and stretching are less likely to occur, and to obtain such a heat-shrinkable polyester tube.

[0008]

A characteristic means of the method for producing a heat-shrinkable polyester tube for achieving the above object is to contain inorganic fine particles and a polyolefin elastomer as described in claim 1. The copolyester is extruded into a tube and then taken into hot water of 95 to 100 ° C. by a pinch roller, and the tube passing through the pinch roller is tubularly stretched to expand the diameter.

The starting materials for the copolyester are:
The dicarboxylic acid component includes terephthalic acid, oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sepacic acid, phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, and the like. One or more kinds of known glycol components such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, polyalkylene glycol, etc. can be adopted as the glycol component. .

Although the copolyester can be obtained in this manner, for use as a heat-shrinkable tube, a copolymer of polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate is preferable, and particularly, A polyethylene terephthalate copolymer is preferable because it is inexpensive and has low crystallinity.

When polyethylene terephthalate is mainly used, a dicarboxylic acid component as a copolymerization component contains isophthalic acid in an amount of 10 mol% or more, and a glycol component contains diethylene glycol or polyalkylene glycol in an amount of 10 mol% or more. Polymerization is preferable, and since these have low crystallinity, for example, the degree of crystallinity is 20.
% Or less can be easily obtained, and the shrinkage property is good, which is particularly preferable.

That is, in the copolyester mainly composed of polyethylene terephthalate, it is preferable that 70 mol% or more of the dicarboxylic acid component is terephthalic acid and 70 mol% or more of the glycol component is ethylene glycol.

In the present application, the copolymerized polyester is made to contain the inorganic fine particles and the polyolefin elastomer as described above. In this case, the temperature is lower than the extrusion temperature and is lower than the conventional cooling temperature of 30 ° C. Is high, 9
It becomes possible to perform operations from the extrusion to the pinch roller in a temperature range of about 5 to 100 ° C., and as described later,
The width unevenness and the drawing unevenness can be kept within a predetermined range over the entire manufacturing process.

The reason why there is no problem even if the temperature is set in such a temperature range is that the polyolefin elastomer present on the surface of the material is softened in the temperature range due to the fact that the polyolefin elastomer is contained, and it is as if the lubricant is used. It is thought to be to exert the effect like. That is, according to such a method, it is possible to efficiently obtain the heat-shrinkable tube without causing adhesiveness at the pinch roller and the nip roller.

The polyolefin elastomer is preferably one or more selected from atactic polypropylene, polyethylene wax, and ethylene-propylene rubber as described in claim 2. When using atactic polypropylene, claim 3
, The average degree of polymerization is 100-300.
It is preferably in the range of.

Further, by containing the inorganic fine particles, it becomes possible to give unevenness to the surface of the tube material formed into a film shape, the adsorptivity on the surface is lowered, and also from this point, slippage can be secured, resulting in By the way, pinch rollers,
It is possible to reduce the problem of sticking at the nip roller portion, and it is possible to avoid unevenness in width and unevenness in stretching over the length extension.

As such inorganic fine particles, claim 4
As described above, it is preferable that the inorganic fine particles are one or more kinds selected from particulate calcium carbonate, diatom oxide, and talc, and have an average particle diameter of 0.1 to 5 μm.

If the inorganic fine particles have such a size,
It is possible to satisfactorily form irregularities on the film surface and sufficiently exert the effect as a lubricant. Incidentally, if the average particle size is less than 0.1 μm, it is difficult to obtain the effect as a lubricant.
On the other hand, if it is larger than 5 μm, it may be an obstacle to film formation.

Further, as described in claim 5, it is preferable that the polyolefin elastomer is contained in an amount of 0.1 to 1.5 wt% with respect to the total amount of the tube material.

If this ratio is lower than 0.1 wt%, slippage between film materials may not be ensured and the dynamic friction coefficient may not be sufficiently lowered. For example, when a 50 m heat-shrinkable tube is continuously molded, width unevenness and stretching unevenness tend to occur. On the other hand, this ratio is 1.
If it exceeds 5 wt%, the dynamic friction coefficient will be sufficiently reduced,
This causes inconveniences such as loss of surface gloss and lower product evaluation.

When the polyolefin elastomer and the inorganic fine particles are contained together, the polymerization ratio of the polyolefin elastomer in the mixture of the inorganic fine particles and the polyolefin elastomer (weight of the polyolefin elastomer / weight of the mixture) as described in claim 6. Is preferably 0.15 to 0.45.

When the above ratio is lower than 0.15, the ratio of the inorganic fine particles becomes excessive, and a situation similar to the case where only the inorganic fine particles are mixed with the polyester resin appears. In this case, the dynamic friction coefficient tends to be maintained in a relatively high state, and continuous molding of the heat-shrinkable tube may be difficult. On the other hand, if it is greater than 0.45, the proportion of the inorganic fine particles becomes too small, and the roughness of the tube surface decreases, resulting in too smooth a surface. As a result, the adsorptivity of the heat-shrinkable tube increases, and the dynamic friction coefficient also tends to increase.

The heat-shrinkable polyester tube obtained as described above comprises, as described in claim 7 or 8, a copolymer polyester containing inorganic fine particles and a polyolefin elastomer. 1 to 1.5 wt% of the heat-shrinkable polyester tube produced by tube extrusion after being extruded into a tube, or a weight ratio of polyolefin elastomer in a mixture of inorganic fine particles and a polyolefin elastomer (polyolefin). Elastomer weight / mixture weight) is 0.15
The value is 0.45, the production state is stable, and the product is good.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a heat-shrinkable polyester tube of the present invention will be specifically described with reference to the drawings. Also in the production method of the present application, a crystalline polyester containing an appropriate amount of a lubricant is dried under the same drying conditions as for ordinary polyethylene terephthalate or a copolymer thereof, and then subjected to tube extrusion to obtain a tube. Here, both the inorganic fine particles and the polyolefin elastomer are selected as the lubricant in the present application.

At the time of manufacture, as shown in FIG. 1, a pinch roller 1 for pulling out is provided in hot water,
The tube 3 is connected to the pinch roller 1 via the guide roller 2.
Shall be reached. The temperature of the hot water is 95 to 100 ° C, which is a setting unique to the present application. At this time, between the ring-shaped die 4 and the pinch roller 1, the tube 3 is stretched by 2 to 4% in the longitudinal direction along the drawing direction.

After being drawn out from the hot water, the tube 3 is stretched in the longitudinal direction and the radial direction by increasing the internal pressure of the tube by using the tubular stretching device 5 equipped with the nip roller 5a. At that time, the draw ratio is 1 to 1.7 times in the longitudinal direction, preferably 1 to 1.4 times, and 1.7 to 4 times in the radial direction, preferably 1.8 to 3.5 times. And The stretching pressure during stretching is shown in Table 1 below.
In this stretching operation, the stretching temperature is preferably low and is selected from the range of about 75 to 95 ° C. as long as the width unevenness and the stretching unevenness are not deteriorated. The stretched tube thus obtained is wound into a product.

The thickness of the tube obtained as described above is not particularly limited, but as a shrinkable tube for coating a capacitor, it is usually 50 to 100 μm, preferably 8
It can be set to 0 to 90 μm.

[Experimental Example] In order to verify the superiority of the method of the present invention, experiments shown in Tables 1, 2, and 3 were conducted. In these tables, the vertical axis represents the sample number and the horizontal axis represents the molding conditions and the physical properties of the obtained sample.

Table 1 mainly shows the results of verification of formability and measurement of dynamic friction coefficient. Table 2 shows the results of mainly verifying the density and crystallinity. Table 3 shows the results of verifying the wall thickness and the shrinkage rate.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

In the experiment, as shown in the margins of Table 1, type A and type B copolyesters were used. Details of both types are given at the beginning of the Examples section below.

In these tables, Nos. 1 to 9 represent samples under different conditions.
Suffixes for Nos. 4 and 5 are different methods for measuring density (density gradient tube method and JIS
K-7112). No1-6,
Nos. 8 and 9 are for type A polyester, No7
Only was the type B polyester. Furthermore, No1
The weight of the mixture (the mixture of the inorganic fine particles and the polyolefin elastomer) was increased toward ˜6.
Here, the No. 1 corresponds to the one without the mixture,
No. 8 corresponds to a mixture of only inorganic fine particles. The mixing amount can be compared with that of No2.

Further, in No. 9, the amount of the mixture is substantially the same as that of No. 3, and the amount relationship between the inorganic fine particles and the polyolefin elastomer is changed.

Describing the sample No., Sample Nos. 1 and 8 are comparative examples of the present application, and Samples 2 to 7 and 9 correspond to the examples of the present application. In Table 1, the bath temperature indicates the temperature of the hot water tank 6 in which the guide roller 2 and the pinch roller 1 are present, and the drawing pressure indicates the internal pressure when performing the tubular drawing.

The methods adopted for determining the physical properties will be described below in correspondence with the descriptions in the table. (1) Appearance of tube Visual inspection was performed on the appearance of the heat-shrinkable tube obtained as a finished product. The situation was determined by observing whether or not the surface was rough, with the main point of view being whether or not the surface of the tube had gloss. In the table, the ones marked with a circle show that they have the same or better appearance than conventional products. On the other hand, the mark Δ indicates that the sample is usable although it is slightly inferior in gloss to the sample marked with a circle.

(2) Dynamic Friction Coefficient (μ ₀ ) According to JIS K-7125, the lower test piece is 25 mm ×
300 mm, upper test piece is 20 mm x 60 mm, and sliding piece has a holding surface of 25 mm x 65 mm 300
It was measured by pulling the upper test piece as g.

(3) Evaluation of Tube Moldability As described above, in the case of continuous molding, in forming several tens of meters (10 to 50 m), the width unevenness is ± 2% or less and the drawing unevenness is in the longitudinal direction (longitudinal direction). ) ± 3% and lateral direction (width direction) ± 9% or less as a reference. That is,
When this condition was satisfied, it was judged as "○", and when it was out of this condition, it was judged as "X".

(4) Density and Crystallinity The material density is determined by the "density gradient tube method" and "JIS K-7".
112 ”to obtain the actual measured density Dx (gr / cm ³ ). The suffixes were changed between the two and the results are shown in Table 2. For example, in Table 2, No. 3-1 and No. 3-2 indicate that the former is based on the density gradient tube method and the latter is based on JIS, as described in the remarks column. Further, the corrected density Dpet (gr / c
m ³ ) was calculated.

[0041]

[Equation 1]   Density correction formula 1 / Dx = (α / Dp) + (β / Dt) + (1-α-β) / Dpet- (1)   Each description in the above formula is as follows. Measured density of Dx stretched tube (listed in Table 2) Dp polyolefin density         (Substance; atactic polypropylene, density; 0.88) Dt Density of inorganic fine particles (substance; calcium carbonate, density; 2.68) Dpet Density of stretched tube with zero addition of inorganic fine particle polyolefin α wt% of polyolefin added / 100 (listed in Table 2) β Addition of inorganic fine particles wt% / 100 (listed in Table 2)

Further, based on the corrected density Dpet obtained as described above, the crystallinity X% was obtained according to the following equation 2 shown in the equation (2).

[0043]

## EQU00002 ## Calculation formula of crystallinity (applicable only to type A) X (%) = Dc (D-Da) / D (Dc-Da)-(2) In the above formula, each description is as follows. . D is Dpet Dc = 1.455 in formula 2 (density of perfect crystal) Da = 1.335 (density of perfect non-crystal) Since type B is amorphous, its crystallinity was not calculated.

(5) After immersing in hot water having a shrinkage rate of 100 ° C. for 10 seconds, it was determined by the following equation 3 shown in equation 3. In Table 3, what is described as the length direction is a direction along the take-up direction which is the longitudinal direction of the tube, and the radial direction means the radial direction of the tube, that is, the direction orthogonal to the length direction. means.

[0045]

[Equation 3] Shrinkage (%) = 100 x (dimension before shrinkage-dimension after shrinkage) / dimension before shrinkage- (3)

[0046]

EXAMPLE A type A dicarboxylic acid component is 78 mol% terephthalic acid, isophthalic acid is 22 mol%, a glycol component is ethylene glycol, a copolyester having an intrinsic viscosity of 0.71, and a polyolefin elastomer (specifically, atactic polypropylene). And the addition amount is wt in Tables 1 and 2.
%), And a mixture of polyethylene terephthalate having an intrinsic viscosity of 0.8 to 0.9 containing calcium carbonate as inorganic fine particles (addition amount is expressed in wt% in Tables 1 and 2) by a conventional method. Then, the tube was extruded to obtain a tube having a predetermined outer diameter and a predetermined thickness.

Type B dicarboxylic acid component is 78 mol% terephthalic acid, naphthalene dicarboxylic acid 22 mol%, glycol component is a copolyester of ethylene glycol having an intrinsic viscosity of 0.71 and a polyolefin elastomer (specifically atactic Polypropylene, the addition amount of which is shown in wt% in Tables 1 and 2) and calcium carbonate as inorganic fine particles (the addition amount of which is indicated in wt% in Tables 1 and 2) A 0.9 wt% polyethylene terephthalate dwt% mixture was dried by a conventional method and then extruded into a tube to obtain a tube having a predetermined outer diameter and a predetermined thickness.

In the apparatus system shown in FIG. 1, the temperature of the bath 6 is 95 to 100 ° C. as shown, and the bath 6 is
After being drawn out from the above, it is tubularly stretched in the length direction and the radial direction at a temperature of 85 to 95 ° C., a folding diameter of 17 mm, and a thickness of 8
A drawn tube of 0 to 90 μm was obtained.

The following can be said from Tables 1 and 2. (1) Copolyester is made to contain both inorganic fine particles and a polyolefin elastomer, and this is extruded into a tube and drawn into hot water of 95 to 100 ° C. by a pinch roller, and the tube passing through the pinch roller is tubed. It is possible to satisfactorily manufacture the heat-shrinkable polyester tube by stretching the wire by expanding the diameter of the heat-shrinkable polyester tube. On the contrary, No1
As in No. 8, no polyolefin elastomer or inorganic fine particles are added at all, or No. 8 only inorganic fine particles are added, there is a problem in continuous molding. Although not shown in the table for the case where only the polyolefin elastomer is added, there is a problem that the sizing tube (provided in the tubular drawing device 5) is caught during the diameter expansion after the pinch roll and the tube bursts. was there. (2) The proportion of the polyolefin elastomer is 0.1 to 1.5 wt% with respect to the total weight, and the weight proportion of the polyolefin elastomer in the mixture of the inorganic fine particles and the polyolefin elastomer (polyolefin elastomer weight / mixture weight). ) To 0.1
It is preferably set to 5 to 0.45. This range is based on whether or not continuous molding is possible (indicated by O and X in Table 1), whether or not the appearance is good, and whether or not the coefficient of dynamic friction is low (indicated in Table 1). Were determined. (3) By adopting such a manufacturing method, the crystallinity becomes less than 4% as shown in Table 2. (4) By adopting such a manufacturing method, as shown in Table 3, about 10% in the longitudinal direction and 40 in the radial direction.
It is possible to obtain a heat-shrinkable polyester tube having a shrinkage characteristic of not less than%.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, after the copolyester containing the inorganic fine particles and the polyolefin elastomer is extruded by the tube, the copolyester is taken up in hot water of 95 to 100 ° C. and appropriately drawn At least 10
It was possible to realize a good manufacturing state in which the width unevenness was ± 2% or less, the stretching unevenness was ± 3% or less in the longitudinal direction, and ± 9% or less in the lateral direction over a length of 00 m. The heat-shrinkable polyester tube thus obtained has a shrinkage rate of 40% or less in the length direction and 40% or more in the radial direction when immersed in hot water of 100 ° C. for 10 seconds, and has an inner surface. The coefficient of dynamic friction was less than 0.4, which was practically preferable.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a molding apparatus using the manufacturing method of the present application.

FIG. 2 is a diagram showing a configuration of a molding apparatus using a conventional manufacturing method.

[Explanation of symbols]

1 pinch roller 2 Guide roller 3 tubes 4 ring die 5 Tubular stretching device (sizing tube) 6 hot water tank 60 cooling tank

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23:00) B29K 67:00 B29K 67:00 B29L 23:00 B29L 23:00 F term (reference) 4F210 AA01 AA04 AA09 AA11A AA11B AA24 AA45 AB16 AB17 AG08 AR06 QA05 QG04 QG18 RA05 RC02 RG02 RG07 RG43 4J002 BB002 BB032 BB132 BB152 CF001 CF061 CF071 CF081 DE236 DJ016 DJ046 FD016 GM00 GT00

Claims (10)

[Claims] 1. A copolyester containing inorganic fine particles and a polyolefin elastomer is extruded by a tube and then taken into hot water of 95 to 100 ° C. by a pinch roll, and the tube passing through the pinch roll is tubular. A method for producing a heat-shrinkable polyester tube which is stretched to expand its diameter. 2. The method for producing a heat-shrinkable polyester tube according to claim 1, wherein the polyolefin elastomer is at least one selected from atactic polypropylene, polyethylene wax, and ethylene / propylene rubber. 3. The average degree of polymerization of the atactic polypropylene is in the range of 100 to 300.
A method for producing the heat-shrinkable polyester tube described. 4. The inorganic fine particles are one or more kinds selected from particulate calcium carbonate, diatom oxide, and talc, and have an average particle diameter of 0.1 to 5 μm. A method for producing a heat-shrinkable polyester tube. 5. The polyolefin elastomer comprises:
The method for producing a heat-shrinkable polyester tube according to claim 1, wherein the heat-shrinkable polyester tube contains 0.1 to 1.5 wt%. 6. The weight ratio of the polyolefin elastomer in the mixture of the inorganic fine particles and the polyolefin elastomer (polyolefin elastomer weight / mixture weight) is 0.15 to 0.45.
6. A method for producing a heat-shrinkable polyester tube according to any one of items 1 to 5. 7. A heat shrinkage produced from a copolyester containing inorganic fine particles and a polyolefin elastomer, containing 0.1 to 1.5 wt% of the polyolefin elastomer, extruded into a tube, and then stretched into a tubular shape. Sex polyester tube. 8. The weight ratio of the polyolefin elastomer in the mixture of the inorganic fine particles and the polyolefin elastomer (polyolefin elastomer weight / mixture weight) is 0.15 to 0.45.
The heat-shrinkable polyester tube described. 9. The heat-shrinkable polyester tube according to claim 7, which has a crystallinity of less than 4%. 10. The heat-shrinkable polyester tube according to any one of claims 7 to 9, wherein the radial shrinkage is in the range of 40 to 60%.