JPS6082343A - Sheet for forming shrinkable sleeve - 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 sheet for forming a shrinkable sleeve, and is it suitable as a material for a shrinkable sleeve for covering and protecting glass bottles containing carbonated drinks, etc.? trying to provide.

Conventionally, the outer surface of a glass bottle, etc. is covered with a sleeve made of a heat-shrinkable thermoplastic resin sheet, and the sleeve is completely shrunk by heating to cover the outer surface of the glass bottle, etc., so that the sleeve adheres tightly to the outer surface of the glass bottle, etc. Efforts are being made to provide buffer protection.

Particularly in the case of glass bottles that are subject to internal pressure, such as carbonated beverages, it is an important safety issue to prevent breakage as well as to prevent bottle fragments from scattering when broken.

Among the various synthetic resin sheets conventionally used as materials for sleeves, foamed polyolefin sheets are highly flexible and are therefore suitable for preventing glass bottle fragments from scattering when the bottle is broken. When the above-mentioned polyolefin foam sheet is used to form a sleeve and cover a bottle, each sheet itself is too flexible and has low rigidity or stiffness, making it difficult to handle the sheet, and the sheet may be difficult to handle. There is a problem that the sleeves are distorted and bent, making it difficult to coat the bottles smoothly.In particular, it is extremely difficult to mechanize or automate the process of winding the sleeve and coating the bottles.
This caused a decrease in productivity.

Therefore, in the present invention, the drawbacks of the above-mentioned foamed polyolefin resin sheet should be solved (improved), and its composition is made of a shrinkable foamed polyolefin resin sheet and a shrinkable non-foamed polystyrene resin sheet. It is characterized by being laminated with films.

Next, embodiments of the present invention will be illustrated below with reference to the drawings.

ill is a shrinkable foamed polyolefin sheet such as a shrinkable foamed polyethylene sheet, and +21tj is a shrinkable non-foamed polystyrene film. At least both sheets (1) and film (2) are laminated to form a shrink sleeve forming sheet C.
B) constitute '.

The above-mentioned shrinkability is imparted to the foamed sheet (1) and the non-foamed film by stretching when 1 is manufactured by extrusion molding, or by a subsequent stretching process after molding.

The foamed sheet (1) is low density polyethylene, straight-stripe low density polyethylene, and high density polyethylene.

Polyglopylene, polybutene-1. Foamed sheets made of polyolefin resins such as ethylene-acetic acid/vinyl acid copolymers alone or copolymers, or mixed resins can be used. In addition, as a zero-order non-foamed film (2), which is the same as conventional foamed sheets, the above resin is blended with additives such as 1 foaming agent, 2 foaming nucleating agents, a spreading agent, and a plasticizer. ,polystyrene.

A film made of a single or copolymer of styrene resin such as high impact polystyrene, AB811 resin, A8 resin, or a mixed resin can be used.

Further, the non-foamed film (2) is also blended with additives such as a white pigment such as titanium white, a lubricant, a weathering agent, an antistatic agent, etc. to produce white discoloration.

Furthermore, the non-foamed film (2) is tri-blended with styrene rubber such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-ethylene-butylene-styrene copolymer, and styrene-butadiene rubber. , can be used in combination.

1% applied, shrinkable non-expanded polystyrene film (2
It can also be carried out by laminating a shrinkable non-foamed polyolefin film on the outer surface of the film.

In this case, a non-foamed film made of the same resin as the foamed polyolefin sheet (1) can be used as the polyolefin film.
If a vinyl acetate copolymer resin is mixed, the lamination adhesion with the polystyrene film (2) will be good and suitable.

Next, the thickness of each of the above sheets or films is usually 0.1 to 1.0 mm for the foamed polyolefin sheet (1), and 0.1 to 1.0 mm for the non-foamed polystyrene film (+2) or 0.1 to 1.0 mm for the non-foamed polyolefin film (1). 005~0.10
A range of 0 m is used. In particular, the thickness of the sleeve forming sheet (2) to be manufactured is 1. If the OJEI or less, foam sheet (1) is 0.15 to 0.5 (1 m, non-foamed film A (21 (21 is 0.010 NO, 05
01['% applied.

Methods for producing the shrinkable sleeve forming sheet (8) in which the foamed sheet (1) and the non-foamed film (2) are laminated with the composition as described above include a method of laminating them at the same time as molding by coextrusion; Either the sheets (1) and the film (2) are formed separately in advance and then directly thermally bonded, or
Any method of laminating by thermal bonding via an adhesive layer can be used.

In the coextrusion method, raw resins for the foamed sheet (1) and non-foamed film (2), which are melt-kneaded separately in multiple extruders, are put into a joining mold (annular or flat) or an adapter. Introduced, combined and extruded at the same time,
When the laminated sheets are taken up by a take-up machine via a take-up plug or roll, the sheet is stretched in the flow direction due to the difference between the linear velocity of the resin melt at the tip of the mold and the sheet take-up speed. Sleeve forming sheet (8
) gives a contractility of 7.

In addition, the thermal bonding method involves bonding a foamed sheet 1-(11), which has been manufactured in advance by extrusion molding or the like and has been given shrinkage, and a non-foamed film (2) with an adhesive layer (3) interposed therebetween, or by directly heating They are joined and laminated into one piece.

As the adhesive layer (3), a vinyl acetate-based hot-melt adhesive can be suitably used, and for direct thermal bonding without the intervention of the adhesive layer 131, a foamed sheet (
1) or non-foamed film +21 [For 21, use a combination of resin materials with good adhesion to each other, or add ethylene-vinyl acetate copolymer to the raw resin in advance.

By mixing resins such as vinyl acetate, styrene-butadiene copolymer, styrene-isoprene copolymer, and styrene-butadiene rubber, you can create a foamed polyolefin sheet (1) and a non-foamed polystyrene film (2) made of different materials.
), or non-foamed polystyrene film (2) and non-foamed polyolefin film (2) can also be thermally bonded.

In addition, when laminating by the above-mentioned thermal bonding method, the foamed sheet (1) and the non-foamed film 121 [21] used have the same degree of shrinkage. That is, it is preferable to use materials that exhibit approximately the same degree of shrinkage at the same heat shrinkage temperature, since the shrinkage does not decrease after lamination by thermal adhesion.

In addition, by combining the above-mentioned coextrusion method, thermal bonding method with an intervening adhesive layer (3), and thermal bonding method without intervening an adhesive layer (3), a single sheet for forming a sleeve can be obtained.
(S) can also be produced. For example, the embodiment shown in FIG. 1 is a foamed sheet (1) and a non-foamed polystyrene film (2) thermally bonded via an adhesive layer (3), and the modified example shown in FIG. Foamed polyolefin film (2), non-foamed polystyrene film (2),
and foamed polyolefin film (2) and foamed polyolefin film (2), respectively, thermally bonded through adhesive layer (3). 3) Direct heat bonding across the gap. Figure 6 shows a foamed sheet (1) and both non-foamed films (2) (2) laminated together at the same time as molding by coextrusion.

Next, the laminated sheet (S) needs to have heat-shrinkable properties, and for that purpose, the foam sheet (1
) and the non-foamed film + 21121 must both have shrinkability, but normally the shrinkability of the non-foamed film (21121) may be slightly smaller than that of the foamed sheet (1).In particular, When produced by a coextrusion method, there will naturally be a difference in the temperature at which shrinkage occurs due to differences in the composition of each sheet (1) and film 12+ (i).

A sleeve (6) is formed by winding it into a cylindrical shape, overlapping both ends, pressing them together, and joining them with thermal adhesive.
(See Figure 2).

When joining the ends, the inner surface of the foamed sheet (1) and the outer surface of the non-foamed film (2) or (2) are thermally bonded, so the foamed polyolefin sheet (1) Thermal adhesion is good when bonding a non-foamed polyolefin film (21). However, when bonding a non-foamed polyolefin sheet (1) and a non-foamed polystyrene thread film (2), film(
2) Alternatively, it is effective to mix a resin with good adhesiveness, such as vinyl acetate, into the foamed sheet (1) to improve the thermal adhesiveness.

Next, place the glass bottle ((
The glass bottle 0 is protected by covering it with IK and heat-shrinking it so that it tightly covers the glass bottle (2) along K (see Fig. 8).

The sheet for forming a shrinkable sleeve of the present invention (according to 8HC) constructed as described above has a laminated structure of a single foam polyolefin sheet (1) and a non-foam polystyrene film (2). Synergistically combines the features of foamed polyolefin sheet (1), which has excellent bottle properties (prevents scattering of bottle fragments) and impact resistance from falling balls, and non-foamed polystyrene film (2), which has excellent rigidity and stiffness. This makes it suitable as a protective sleeve for pressure bottles for carbonated beverages, etc., and also facilitates handling of the sleeve-forming sheet (8), for example, manufacturing the sleeve (for example, into a sleeve), or coating the glass bottle 0.

In other words, the foamed polyolefin sheet (1) alone is weak and difficult to handle, but by laminating the non-foamed polystyrene film + 21 ft, the sleeve-forming sheet (8) increases the overall rigidity and becomes stronger. It is very easy to handle sheets (for example, winding a sleeve (2) or coating a glass bottle (q)).

Therefore, in particular, the formation of the sleeve (6) and the glass bottle (Q
It becomes easy to automate or mechanize the coating work, etc., and it becomes very convenient.

Next, one specific example will be explained by showing detailed data.

Example I First, the following sheet and film (6) (1) and 0 were produced individually and then laminated by thermal adhesion to produce a sleeve-forming sheet (8).

■ Shrinkable foamed polyethylene sheet (thickness 0.170m, density 0.480F/CC, extrusion molded product) (b) Biaxially stretched polystyrene film (thickness 0.020m5 density t)
o5p/cc) (Q-axis stretched polyethylene film (thickness 0.080
(density: 0.92B9/CL) A hot-melt vinyl acetate adhesive (3) is applied to the surface of the foamed sheet (1) (6), and the non-foamed film (6) is heated to 100°C. It was supplied together with (2) to a laminating machine, and ■(B) ft was laminated.

Next, the same adhesive (3) as above was applied to the above bonded sheets, and after heating at 110℃ as above, (non-foamed film of C1)
2) was laminated to produce a sleeve-forming sheet (8) (see Figure 4).

In addition, in order to compare with the above-mentioned example, the following foamed sheet (6) and non-foamed film (b) were manufactured using ffP4.

(5) Shrinkable foamed polyethylene sheet (thickness 0.21 scale, density 0.450 F/cc) (b) - Axial stretched polyethylene film (thickness 0.08 scale, density 0.928 gL/CC) Above examples When comparing the results with the comparative example, the measured values shown in the table below were obtained.

In the table, ring crush strength was measured in accordance with JIa P8126 (paperboard compressive strength testing method).

However, sample size 158ia (sheet flow direction) x I
Bwx (width direction) 0 Since the above ring crush strength is a value that indicates the rigidity or waist strength of the seat, it is thought that a ring crush strength of about 8 kg or more can be used satisfactorily in practice.

Therefore, the example has far superior ring crush strength and greatly improved rigidity compared to the comparative example.

When the sleeve forming sheath (8) of the above embodiment was used in a bottle winding machine that automatically performs the forming of the sleeve (q), covering and shrinking the bottle (0), it was found that the lower end of the bottle (q) Even when it hit the end face, the sleeve (5) could be well covered with the bottle (Q) without causing the sleeve (5) to become dented or bent, and the shrinking work could also be carried out properly.

Example■ Unlike the above example, it was manufactured using a coextrusion method.

Raw material composition (6) Foam sheet (1) Low density polyethylene (M work = 1.OF710m.

Density s, y, = Q, 921p/CC) 85 parts by weight ethylene-vinyl acetate copolymer (MI = 0.59/10
1 flll, VAo amount 15%) 15 parts by weight Foaming agent - Hydrocerol (trade name, manufactured by Ni-Dainichisei Chemical Industry Co., Ltd.)
1.0 parts by weight Building agent - talc 1.0 parts Spreading agent - polybutene 0.1 parts by weight 65 g of the above resin was extruded from the extrusion base at an extrusion rate of 17/h to 60
Extrude using a Y5 mold.

((Support) Non-foamed film (2) Polystyrene (MI=8.57/10 start, S, p, = 1
．． 05F/CC) 80 parts by weight 7 Brene A (trade name: Kaiyakasei Co., Ltd., styrene-butadiene copolymer, 60% steel, 40% rubber) 70 parts by weight The amount of the above resin extruded from a 40y5 extruder It is press-fitted into the co-extrusion adapter at the front of the Cirqueera mold at 2.0 to 1/2 hours, and is bonded around the resin melt for the foamed sheet and extruded.

(Q Non-foamed film (2) Low density polyethylene (MI = 8.Of710 beginning.

+3. p, = 0.9285'/CC) 70 parts by weight Ethylene-vinyl acetate copolymer (Ml = 2.8 li/Summer 0-1■□.Amount 25%) 80 parts by weight Titanium white 1.5 parts by weight Polybutene 0.2 parts by weight of the above resin was extruded from a separate 40521 extruder in an amount of 8.
At 0KGI/H, press fit into a different coextrusion adapter from the above, combine around the rod where the foamed sheet resin melt and the non-foamed polystyrene film resin melt are integrally combined, and extrude them together. .

The sleeve-forming sheet (8) of the example produced as described above and the laminated sheet of the comparative example excluding the non-foamed polystyrene film (2) of (B) from the above example were manufactured, A comparison between the two is shown in the table below.

It is clear from the table above that the examples have much higher throughput and ring crush strength than the comparative examples, and are superior in rigidity and stiffness.

[Brief explanation of the drawing]

The figures illustrate an embodiment of the present invention, and FIG. 1 is a sectional view, FIG. 2 is a perspective view of the sleeve, FIG. 8 is a sectional view of the used state, and FIGS. 4 to 6 are modifications. FIG. 3 is an example cross-sectional view. (1)...Foamed sheet (2)...Non-foamed polystyrene film (me...Non-foamed polyolefin film (3)
... Adhesive layer (8) ... Sleeve forming sheet. Patent applicant Sekisui Plastics Co., Ltd. Figure 1 Figure 1 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A sheet for forming a shrinkable sleeve, characterized in that a shrinkable foamed polyolefin resin sheet and a shrinkable non-foamed polystyrene film are laminated together. 2. A shrinkable non-foamed polystyrene film. The sheet for forming a shrinkable sleeve according to claim 1, wherein a shrinkable non-foamed polyolefin film is laminated on the outside of the polystyrene film.