JPS59155478A - thermoplastic elastic tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic tape that is economical and has excellent elasticity.

Conventional 1 For example, in order to improve the adhesion to the thighs when wearing a disposable diaper, etc., 1 a rubber cord 1 is stretched and pasted with urethane foam etc. on the side of the disposable diaper where the disposable diaper and the thighs come into close contact.
and then remove the tension.

A method has been used that takes advantage of the elasticity of rubber strings, etc., and provides a part of the elastic gears. However, these materials are expensive. A possible improvement measure would be to make the material thinner, but this would be difficult in terms of moldability, so there was a desire for an elastic tape that was inexpensive and easy to handle.

As a result of various studies from this perspective, the present inventors found that
The inventors discovered that a low-cost tape with excellent elasticity could be obtained by combining a thermoplastic resin made of butadiene resin and/or polyolefin resin with an aromatic vinyl compound-conjugated diene copolymer, and the present invention was completed. .

That is, 1 the present invention is a thermoplastic resin consisting of a butadiene resin and/or a polyolefin resin of 20 to 80% by weight and an aromatic vinyl compound-conjugated diene copolymer of 80 to 20% by weight.
% by weight.

The polyolefin resin used in the present invention is polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, etc., while the butadiene resin is 1.2 polybutadiene, etc. These thermoplastic resins can be used alone or in combination of two or more. However, it is moldable and stretchable.

From the viewpoint of mechanical strength, 1,2 polybutadiene is preferable,
Its 1,2 bond content is 70 or more, especially preferred.
L<Hss% or more, and the crystallinity is preferably 5 to 40%, particularly 5 to 30%. If the degree of crystallinity is less than 5 inches, the strength as a tape will decrease, and if the degree of crystallinity is too high, elasticity will be impaired. 1.2 The molecular weight of polybutadiene can be selected from a wide range, but from the viewpoint of moldability and strength as a tape, toluene solution 30
Intrinsic viscosity [η] measured at °C: 0.5 or more, especially 0.7 to
1.5 is preferred.

Examples of the aromatic vinyl compound of the aromatic vinyl compound-conjugated diene block copolymer used in the present invention include styrene and α-mayalsterene, with styrene being particularly preferred. Further, as the conjugated diene, 1,3-butadiene, isoprene, etc. can be used.

This block copolymer has a molecular weight of 50,000 to 250
．． 000 with an aromatic vinyl compound content of 5 to 50% by weight. If the molecular weight is too high, moldability will be poor, and if it is too low or too low, the strength of the tape will be reduced. If the content of the aromatic vinyl compound is more than the above range, the elasticity will be impaired, and if it is less, the strength of the tape will be reduced.

There are no particular restrictions on the structure of the block copolymer;
(8-B) n-type, (A-B) n-A type or (A-B
) n-C type etc. can be used. In the formula, the symbol represents a polymer block of an aromatic vinyl compound, B represents a conjugated diene polymer block, C represents a multi-coupling agent, and n represents an integer of 1 or more. In addition, in the above block copolymer,
Of course, it is also possible to use a block copolymer in which the conjugated diene portion is hydrogenated.

In the composition of the present invention, the mixing ratio of the thermoplastic resin consisting of butadiene resin and/or polyolefin resin and the aromatic vinyl compound-conjugated diene block copolymer is 20 to 800 to 80
Weight% aromatic vinyl compound-conjugated diene block copolymer 80-20% by weight, particularly preferably thermoplastic resin 30%
-70% by weight, the aromatic vinyl compound-conjugated diene block copolymer is 70-30 tqb. If the thermoplastic resin is less than 20% by weight, moldability will be poor.

If it exceeds 80% by weight, the elasticity will be impaired, which is not preferable.

It is of course possible to incorporate various compounding agents such as fillers such as calcium carbonate, oils, plasticizers, lubricants, pigments, and stabilizers into the composition of the present invention.

The method of mixing the composition of the present invention is generally used mixing method 1.
For example, screw extruders, Banbury, kneaders
, Roll et al.'s method is used.

Further, a mixing method using a tumbler, a Henschel mixer, etc. can also be used for preliminary mixing.

As a method for manufacturing the elastic tape of the present invention, ordinary melt extrusion molding methods such as inflation molding and T-die molding are suitably used.

The elastic tape of the present invention has an excellent permanent elongation (test method shown in the examples) of 50% or less, preferably 30 inches or less. Furthermore, it has excellent elasticity, low cost realized by the manufacturing method, and excellent processability, and can be used as a substitute for conventional rubber cords and other applications. The elastic tape of the present invention is particularly suitable for applications that do not require much durability, such as tape products for binding disposable products such as disposable diapers and travel pants.

It is also possible to laminate an adhesive composition on the elastic tape of the present invention to obtain an elastic adhesive tape, which improves workability when attaching the tape in the above applications. (9) The elastic tape of the present invention has the advantage that it can be attached to the site of use by heat sealing by utilizing its thermoplasticity.

In order to explain the unexploded 8A'fc in more detail, examples will be given below, but the present invention is not limited to these unless it goes beyond the spirit of the present invention.

The molding method and evaluation method of the films used in Examples and Comparative Examples are shown below.

<Film forming method> Screw extruder 1c, J:51
Film formation was performed at 5° C. using an extrusion T-die.

<Moldability evaluation method> Evaluation was made based on the difficulty of T-die film molding.

Judgment criteria ◎ Film formability is very fJ n 1 20
// It's elegant.

△ Slightly inferior.

×Film molding is not possible.

(For compositions that could not be formed into a film by T-die molding, a film was made by press molding and used for evaluation of elasticity.) <Stretchability evaluation method> l) Width 15+on, length 1Ocrn Short fence-shaped test piece'f
c was prepared and tested.

2) Apply 200% elongation to the test piece for 2 minutes.

The length R) of the test piece was measured 2 minutes after the elongation was released.

3) Permanent elongation was calculated using the following formula.

Here, 20 represents the original length of the test piece.

Judgment Criteria: The smaller the permanent elongation value, the more stretchable it is.

, Example 1. Comparative example 1 Evaluation was performed using the composition ratios shown in Table 1.

The results are shown in Table 1.

Table 1) Nuterene-butadiene-styrene block copolymer shell chemistry TR2103 2) 1.2 Polybutadiene Made by Nippon Synthetic Rubber R
B820 [1,2 content - 92%, crystallinity = 25 chi, [
η) = 1.20 (3.0℃ toluene)] 3) Polyethylene YK・30 (4I= manufactured by Mitsubishi Yuka ■)
4 (190°C/2160f), specific gravity = 0.92) 4) Etherene/vinyl acetate copolymer manufactured by Toyo Soda UE6
33 (VAc=20.MI=20 190℃-2160
9”J5) Polypropylene Made by Mitsubishi Yuka ■ BC Knee 4
From the results shown in Table 1, the composition of Example 1 according to the present invention was excellent in elasticity and durability.

Comparative Examples 1 (2), (3), and <4) have poor moldability and have large permanent elongation (support) and poor elasticity, making them undesirable.

Example 2. Comparative example 2 Evaluation was performed using the composition ratios shown in Table 2.

The same TR-1,1 and 2-PBD-2 as in Example 1 were used.

The results are shown in Table-2.

Table 2 From the results shown in Table 2, the composition of the present invention has a better balance between moldability and stretchability than the composition of Comparative Example 2.

Examples 3 and 5 Comparative example 3 Evaluation was performed using the composition ratios shown in Table 3.

The same TR-1,1,2-PBD-2 as in Example 1 was used.

The results are shown in Table-3.

Table 3 1) Styrene-butadiene-styrene block copolymer shell chemistry ■ TR2103 2) Styrene-butadiene block copolymer Asahi Kasei ■
T-475 3) Styrene-butadiene random copolymer Japan Synthetic Rubber ■ JAR1so.

From the results in Table 3, it is clear that the composition of the present invention is superior to Comparative Example 3 in moldability and stretchability.

Example 4 Evaluation was performed using the composition ratios shown in Table 5.

The same TR-1 as in Example 1 was used, and 1.2-P
The BD shown in Table 4 was used.

Table 4 Characteristic values of sample 1.2 PBD 1) Infrared absorption spectroscopy by Morrero et al. (chim, etInd, 41.758 (1)
959)).

2) Measured by density method. At that time, crystallinity is 100%
The density of 1,2 PBD is G, Natta (J, Paym
er 8ci, 0.963 of 20.26 (195,6)
The density of 1.2PBl with 0% crystallinity was confirmed to be amorphous by X-ray diffraction (% Kosho 44-
32425. Tokuko Showa 44-L32426) Density 0.89
2 was used.

Table 5 It is clear from Table 5 that both of the compositions of the present invention are excellent in moldability and stretchability.

Claims (1)

[Claims] (20 to 80% by weight of (tri)butadiene resin and/or polyolefin resin) aromatic vinyl compound -
A thermoplastic stretch tape comprising 80 to 20% by weight of a conjugated diene block copolymer. (2) Butadiene resin has a binding gold content of 1.2 7'O1
The crystallinity is 5 to 40%, and the intrinsic viscosity [η] (measured in toluene at 30°C) is 0.7 (d11/f) or more.
2. The thermoplastic stretch tape according to claim 1, which is polybutadiene.