JP2737592B2 - Plastic tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic tube such as a heat-shrinkable tube manufactured by extrusion molding, and more particularly to a plastic tube capable of preventing the occurrence of die build-up adhered to a die or the like during extrusion molding.

[0002]

2. Description of the Related Art Plastic tubes such as heat-shrinkable tubes are widely used for protection of metal pipes or protection or insulation of electric wires. This plastic tube is generally manufactured by extruding plastics, rubber or the like. The heat-shrinkable tube is manufactured through the steps of cross-linking and tube expansion, and a material mainly composed of polyolefin is often used. When flexibility is required, an ethylene copolymer such as ethylene vinyl acetate copolymer may be used.

When such a heat-shrinkable tube is used at a high temperature, an antioxidant or the like is added in order to prevent thermal oxidation deterioration. However, when used in contact with a metal, the deterioration is remarkably accelerated, and it is known that the deterioration is suppressed by further adding a metal deactivator.

[0004]

By the way, as shown in FIG. 2, this plastic tube uses an extruder in which a nipple 2 is inserted into a die 1 as shown in FIG. Is extruded to form a plastic tube 4. In this extrusion molding, the so-called eye filing 5 in which a part of the plastic material adheres and accumulates on the die 1 and the nipple 2 is recognized as a chronic problem to a certain extent. In particular, since the eye mold 5 generated on the nipple 2 is located on the inner surface of the tube 4, there is no appropriate means to remove it during the manufacturing process.
It is a more serious problem.

As described above, the addition of a metal deactivator is indispensable in order to suppress deterioration due to metals at high temperatures.
Addition of this metal deactivator significantly increases eye repellent,
The problem arises that the production of plastic tubes is severely limited. In other words, there is a problem that the probability that the clumps of eye buildup deposited on the nipple adhere to the inner surface of the tube and cause a product defect is remarkably increased.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a plastic tube capable of remarkably reducing eye drop.

[0007]

The gist of the present invention resides in a plastic tube containing a metal deactivator having a hindered phenol and NHCO structure in the molecule.

[0008]

According to the above construction, the use of a metal deactivator having a hindered phenol and an NHCO group in the molecule greatly reduces the occurrence of eye tarnish when a heat-resistant plastic tube is manufactured by extrusion. Can be reduced.

Hindered phenol and NHCO in the molecule
Examples of the metal deactivator having a group include those shown in Chemical formulas 1 to 5.

[0010]

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[0011]

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[0012]

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[0013]

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[0014]

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Among the metal deactivators of Chemical Formulas 1 to 5, Chemical Formula 1
N, N'-bis [3- (3.5-di-t-butyl-4)
-Hydroxyphenyl) propionyl] hydrazine has a large effect, but other chemical formulas 2 to 5 also have a sufficient effect of preventing eye dripping.

Generally, deterioration of the tube is not a problem when the temperature is low, but a metal deactivator is essential at a high temperature. Specifically, when the temperature is 105 ° C. or more in the UL test, it is preferable to add a metal deactivator. If it is less than this, it is not always necessary to add. It can be handled only by antioxidants. Naturally, when the tube is formed by a method other than the extrusion molding, for example, a mold molding, there is no problem of eye repelling.

In the production of a plastic tube, it is an ethylene vinyl acetate copolymer among polyolefins that is liable to cause the tarnish, and the problem of the tarnish is more serious. Therefore, for these materials, the substantial tube can be produced only by the present invention by adding the compounds shown in Chemical formulas (1) to (5).

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, a metal deactivator of formulas 1 to 5 is added to a plastic such as polyolefin, and the plastic material 10 is extruded from between the die 1 and the nipple 2 to form a plastic tube 11 as shown in FIG. At the time of this molding, it is possible to prevent the adhesion of the eye mold to the nipple 2 and the die 1.

Next, more specific examples will be described together with comparative examples.

Table 1 shows Examples 1 to 5 and Comparative Examples 6 to
10 shows the results.

[0022]

[Table 1]

Example 1 Ethylene vinyl acetate copolymer (EV460, vinyl acetate content 19%, melt flow rate 2.5 g / 10 mi)
n, density 0.94, Mitsui Dupont Polychemicals) 10
0 parts by weight, 10 parts by weight of antimony trioxide as a flame retardant and 15 parts by weight of decabromodiphenyl ether, and pentaerythrityl-tetrakis as an antioxidant [3- (3.5
0.5 parts by weight of -di-t-silobutyl-4-hydroxyphenyl) propionate (Irganox 1010, Ciba-Geigy) and 1.0 part by weight of tetrakis (methylenedodecylthiopropionate) methane (Seanox 412S, Shiraishi Calcium) Parts, 0.5 parts by weight of stearic acid as a lubricant, and N, N'-bis [3- (3.5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine as a metal deactivator 0.5 parts by weight of Irganox MD1024 (Ciba-Geigy) were uniformly mixed at 150 ° C. by a pressure kneader. The obtained compound is extruded at 130 ° C. with an inner diameter of 3 m using a 40 mm extruder.
A tube having an outer diameter of 4 mm was extruded at a speed of 20 m / min for 1 hour. Then, eye stains attached to the die were collected and weighed.

The obtained tube was irradiated with an electron beam for 10 minutes.
After irradiation with Mrad and crosslinking, the tube was heated and expanded to an inner diameter of 5 mm. This was shrunk into a copper rod having an outer diameter of 4 mm and heated at 150 ° C. for 7 days, then the tube was removed and the elongation was measured by a tensile test. As a result, as shown in Table 1, there was very little eye drop and the elongation after heating also showed a sufficient value.

Examples 2 to 5 In the same manner as in Example 1, only the metal deactivator was converted into Chemical Formula 2 (Example 2), Chemical Formula 3 (Example 3), Chemical Formula 4 (Example 4), Chemical Formula 5 (Example Plastic tubes were manufactured in place of the metal deactivator of 5), and the dents and elongation after heating were measured.

As a result, all of Examples 2 to 5 have a small amount of eye drop and show sufficient values of elongation.

Comparative Example 6 As a metal deactivator, 3- (N-salicyloyl) amino-1,2,4-triazole (Adekastab CDA-1)
Evaluation was performed in exactly the same manner as in Example 1 except that Asahi Denka Kogyo Co., Ltd.) was used. As shown in Table 1, the number of eyes is very large.

Comparative Examples 7 to 9 As a metal deactivator, decamethylene dicarboxylic acid disalicyloyl hydrazide (ADEKA STAB CDA-6, Asahi Denka Kogyo Co., Ltd.) (Comparative Example 7), a triazine derivative composite (ADK STAB Mark ZS-27) A tube was manufactured in the same manner as in Example 1 except that (Comparative Example 8) and tolyltriazole potassium salt (Stabinol MBTZ, Sumitomo Chemical Co., Ltd.) (Comparative Example 9) were used.

As a result, as shown in Table 1, all of the eyes were remarkably large.

Comparative Example 10 A tube was manufactured in exactly the same manner as in Example 1 except that the metal deactivator was omitted.

As a result, as shown in Table 1, although the amount of eye crepe is small, the elongation after heating is remarkably deteriorated to 20%.

[0032]

As described above, according to the present invention, it is possible to obtain a heat-resistant plastic tube having a small amount of settling and excellent in processability. Plastic tubes with increasing demand can be advantageously manufactured, and their industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram showing a molded state of a plastic tube in the present invention.

FIG. 2 is a view showing a molding state of a conventional plastic tube.

[Explanation of symbols]

 10 Plastic material 11 Plastic tube

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 23:00

Claims (6)

(57) [Claims] 1. Hindered phenol and NHC in a molecule
A plastic tube containing a metal deactivator having an O structure. 2. The plastic tube according to claim 1, which is a heat-shrinkable tube having a rated temperature of 105 ° C. or higher. 3. The plastic tube according to claim 1, wherein the plastic material to which the metal deactivator is added is formed by extrusion molding. 4. The plastic tube according to claim 3, wherein the plastic material is a polyolefin. 5. The plastic tube according to claim 4, wherein the polyolefin contains at least one kind of ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, and ethylene methyl acrylate copolymer. 6. The method according to claim 1, wherein the metal deactivator is N, N'-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
The plastic tube according to any one of claims 1 to 5, which is hydrazine.