JP4701801B2 - Laminated body and tape and packaging body using the laminated body - Google Patents

Description

  The present invention relates to a laminate that can be developed on a tape or a package having resealability.

  In the field of packaging business for packaging various contents, there have been many forms in which a reseal function (reclose function) is added to a package. Most of the packages provided with the reseal function (reclose function) use a physical combination such as a zipper / chuck. However, the method using a physical combination such as a zipper / chuck is difficult to develop into a light package from the viewpoint of cost, and a package with a zipper / chuck has a pinhole during bag making. Because it is easy, it has the problem of requiring advanced bag making technology.

  In order to improve the problems of these zippers / chucks, a package having a reseal function using a resin or a resin composition having adhesiveness has appeared. Here, the resealing function using adhesiveness is referred to as resealability hereinafter. Many proposals have been made as a package form using the laminate having the resealability.

  Prior art 1 (see Patent Documents 1 and 2) discloses a package having resealability by laminating adhesive resin layers by coextrusion and using this laminate for the entire packaging material. . However, the laminate obtained by co-extrusion of these adhesive resin layers is formed into a film by locally extruding the adhesive resin layer in multiple layers by using a special co-extruder. The machine is limited, and since the resin layer having local adhesiveness is extruded in multiple layers, the multilayer part having adhesiveness must be provided in the heat seal part of the packaging material. Therefore, there is a problem that the form of the packaging material is restricted.

  Prior art 2 (refer to Patent Document 3) provides an A / B / C type three-layer / three-layer coextruded multilayer film intermediate layer with an adhesive resin, and provides delamination between A / B or B / C. Proposals have been made to expose the adhesive resin as an intermediate layer by using it, and to provide resealability by adhering the adhesive resin to A or C. Moreover, the proposal which expand | deploys to various uses, such as a cover material, using these techniques is also disclosed. However, this technique is difficult to control the initial strength and reseal strength of the adhesive resin and the A or C layer that delaminates from the adhesive resin. If the initial strength is controlled using delamination, the reseal strength Has the problem of weakening. Further, in the case of the delamination type, there is also a problem that resealability cannot be imparted unless the delamination surface (exposed state of the adhesive resin) is uniform.

Prior Art 3 (see Patent Document 4) has disclosed a laminated body in which a water-based or solvent-based adhesive resin is provided on a polyester base material or the like by a technique such as gravure coating, etc. The development to a member such as a reseal tape using this is described. However, the same applies to the above prior arts 1 and 2, etc., but as an adhesive resin, an elastomer such as ethylene-vinyl acetate copolymer resin or styrene-butadiene-styrene copolymer is used as an essential component. It is what is blended. The reseal function usually needs to express adhesiveness at a finger pressure level, and the tackifier is intended to impart tackiness to the substrate of the elastomer (to improve wettability to the substrate), It is blended in order to improve the molecular mobility of the elastomer by the pressure of about the finger pressure and to improve the adhesion (wetting property) to the substrate. However, tackifiers have problems of migration and dissolution. Moreover, the part which wants to provide resealability with a packaging material is normally once sealed by heat sealing. The pressure-sensitive adhesive resin that has been given pressure-sensitive adhesion by blending a tackifier has improved heat sealability. Depending on the amount and type of tackifier, the packaging material can be sealed However, the heat seal significantly improves the strength, and the initial opening strength is significantly increased.

  Prior Art 4 (see Patent Document 5) discloses a multilayer sheet having tackiness using a low molecular weight amorphous polyolefin having a number average molecular weight of 2000 to 7000 without using a tackifier. However, this level of low molecular weight compounds is accompanied by processing problems and causes a phenomenon such as adhesive residue after re-adhesion / reseal.

In the prior art described above, it is mentioned as an essential component that a tackifier is blended in an elastomer as an adhesive resin. However, satisfactory results are not obtained in terms of the stability of the initial strength and the re-seal performance by adding a tackifier.
Japanese Patent No. 2938186 Japanese Patent No. 3322893 Japanese Patent Laid-Open No. 2002-301786 JP 2003-137314 A JP-A-5-237477

  The present invention has been made in consideration of the above circumstances, and a laminate capable of adjusting initial strength and reseal strength at the time of opening a packaging material without adding a tackifier to an adhesive resin, and An object is to provide a tape or a package using the laminate.

To achieve the above objectives, ie
The invention according to claim 1 is a laminate comprising low density polyethylene, urethane adhesive, biaxially stretched polyethylene terephthalate film, amorphous polypropylene resin, and ethylene-hexene-1 copolymer .
The amorphous polypropylene resin, have a tack, wherein the MFR at JIS K 6760 is propylene -α-olefin copolymer of 0.1 to 50 g / 10 min, a laminate.

According to a second aspect of the present invention, the amorphous polypropylene resin is a simple substance of an amorphous polypropylene resin having substantially no melting peak and crystallization peak by a differential scanning calorimeter (DSC), or this resin. 2. The laminate according to claim 1, wherein the laminate is a resin composition blended in an amount of 50% by weight or more.

The invention according to claim 3 is characterized in that the amorphous polypropylene-based resin has adhesiveness with various base material layers adjacent to at least one of them, and has a plurality of re-sealing performances. The laminate according to claim 1 or 2 .

The invention according to claim 4 is the laminate according to any one of claims 1 to 3 , wherein the reseal strength is in a range of 0.1 to 10 N / 25 mm.

It is a laminated body characterized by using the laminated body of any one of the said Claims 1-4 as a tape which can be resealed.

It is a laminated body characterized by using the laminated body of any one of the said Claims 1-4 as a resealable packaging body.

  In accordance with the present invention, the resin A, such as an amorphous propylene-butene-1 copolymer or an ethylene-vinyl acetate copolymer having a high vinyl acetate content, further includes a resin having adhesiveness without blending a tackifier. Since it is a laminate, it is possible to adjust the initial strength and reseal strength when the packaging material is opened in a tape or a package. In addition, the following effects are achieved.

  1. Compared to a conventional zipper / chuck, an inexpensive tape or package is obtained.

  2. Compared to a conventional adhesive resin containing a pressure-sensitive adhesive-imparting agent, the initial strength and re-sealing at the time of opening the packaging material can be stably performed.

  3. Since it can be resealed stably by pressing, it can be easily handled by people with disabilities, children, and elderly people.

  Hereinafter, an embodiment of the present invention will be described in detail. The laminate of the present invention is characterized by using a resin (hereinafter referred to as Resin A) that is tacky without using a tackifier that most easily affects the initial strength and reseal strength when opening the packaging material. It is what.

  Thus, polyolefin-type elastomer is mentioned as resin A which has adhesiveness even if it does not mix | blend a tackifier. Among the polyolefin-based elastomers, as a result of sincere examination on adhesive resins without blending petroleum resin-based or terpene-based tackifiers, the following materials were confirmed to be suitable.

As one of the materials used as the resin A, an amorphous polypropylene-based resin having substantially no melting peak and crystallization peak by a differential scanning calorimeter (DSC) or 50% by weight or more of this resin was blended. A resin composition is mentioned. The amorphous polypropylene resin, MFR is preferably propylene -α-olefin copolymer of 0.1 to 20 g / 10 min in JIS K6760, as the α-olefin, hexene-1, and the like. Although there is no restriction | limiting about the minimum of MFR, when it considers from the point of workability, 0.1 or more is preferable, and an upper limit is about 50. Further, when the MFR exceeds 50, many low molecular weight amorphous components having an atactic structure are likely to be contained. However, while this low molecular weight component is sticky, it has a problem in terms of migration and stickiness. In that sense, the MFR is preferably about 0.5 to 20 g / 10 minutes. The low molecular weight component having an atactic structure as an amorphous polyolefin resin is excluded from the range of MFR. A typical material for such a resin is Tough Selenium manufactured by Sumitomo Chemical Co., Ltd.

  Usually, since these materials have remarkable self-adhesiveness, an anti-adhesion agent or other crystalline resin may be blended depending on the balance between processability and reseal strength. As an anti-tack agent, inorganic compounds such as talc, silica, alumina and calcium carbonate, and higher fatty acid salts such as magnesium stearate, calcium stearate, zinc stearate and sodium stearate are blended in or added to the resin A. It doesn't matter if you let them.

  In addition, it is possible to blend with a crystalline resin instead of these anti-adhesion agents and control the crystallinity to aim at the anti-adhesion effect. High density polyethylene resin, medium density polyethylene resin, low density Polyethylene resin, ethylene-α-olefin copolymer copolymerized with α-olefin in the range of 3 ≦ α ≦ 20, polypropylene resin, propylene-ethylene random copolymer resin, propylene-ethylene block copolymer resin, 4 ≦ <Propylene-α olefin copolymer, ethylene-vinyl acetate copolymer resin, ethylene- (meth) acrylic acid copolymer resin, ethylene- (meth) acrylic acid copolymerized with α-olefin in the range of α ≦ 20 Examples include crystalline to low crystalline resins such as ester copolymer resins and ionic cross-linked products of ethylene- (meth) acrylic acid copolymer resins. Are, but not restricted to the type, the optimal combination of amorphous resins A and these crystalline resin, the combination of both are compatible are preferred. It is preferable to blend the above-described anti-adhesion agent or crystalline resin so that the concentration as the resin A is 50% by weight or more. If it is less, the resealability is poor. More preferably, it is 75 weight% or more as resin A, More preferably, it is 90 weight% or more.

  Furthermore, the resin A may contain various additives such as various additives other than those described above, flame retardants, slip agents, antiblocking agents, antioxidants, and light stabilizers as necessary.

  As a method for producing a laminate using these resins A, a co-extruded multilayer (cast or inflation) film containing an adhesive resin A using an extrusion lamination or multilayer co-extruder is prepared and dried. Lamination etc. can be created by using a known technique. In addition, since the above-mentioned amorphous resin is soluble in various solvents, it can be diluted with a solvent and laminated on various substrates by various coating methods such as gravure coating, reverse coating, and die coating. It is.

An example of the laminate of the present invention is described below.
<Configuration example-1>
・ Polyolefin resin (1) / Adhesive resin A / Polyolefin resin (2)
The polyolefin resin (1) is strongly bonded to the resin A, and the polyolefin resin (2) has resealability with the resin A.
<Configuration example-2>
・ Polyolefin resin (1) / Adhesive resin A / Polyester resin / Polyolefin resin (1)
The polyolefin resin (1) strongly adheres to the adhesive resin A, and the polyester resin has resealability with the resin A.
<Configuration example-3>
・ Polyester resin / urethane adhesive / aluminum foil / adhesive resin A / polyolefin resin (1)
The polyolefin resin (1) strongly adheres to the adhesive resin A, and the aluminum foil has resealability with the resin A.
<Configuration example-4>
・ Polyester resin / Adhesive resin A / Polyolefin resin (1)
The polyolefin resin (1) strongly adheres to the adhesive resin A, and the polyester resin has resealability with the resin A.

  Not limited to these examples, it is possible to design a laminate including a resin A having adhesiveness by a combination of various materials. For example, as shown in FIG. 1, these laminated bodies use heat-sealable polyolefin resins b1 and b3 on both sides of the laminated bodies of Configuration Examples-1 and 2, so that the tape having a reseal function It can be used as Moreover, as shown in FIGS. 2 and 3, it is also possible to manufacture the laminated bodies of Configuration Examples -3 and 4 as a package.

  When the laminate of the present invention is produced in a tape shape and provided on a package, or when the laminate itself is produced on a package, it is necessary to seal the package by heat sealing. That is, before performing reseal (reseal strength), it is necessary to open the heat seal portion once (initial strength). In this case, the initial strength is preferably 3 to 20 N / 25 mm, and the reseal strength is preferably 0.1 to 10 N / 25 mm. If the initial strength is weaker than 3 N / 25 mm, the sealing performance is deteriorated, and if it is higher than 20 N / 25 mm, the initial opening strength becomes too strong. More preferably, it is 5-15N / 25mm. As an index of reseal strength, reseal is preferably performed at a pressure of about a finger pressure, and when it is weaker than 0.1 N / 25 mm, resealability is poor, and a stronger portion is preferable in terms of the sealability of the reseal portion, Considering ease of opening, 10 N / 25 mm or less is preferable.

  As described above, the laminates obtained in various configurations can be directly developed into packaging bodies for various uses. These examples are not limited to the contents described above, and can be developed into various packaging forms.

  Examples of the present invention are shown below, but the present invention is not limited to them.

[Create laminate]
The following materials were used as the adhesive resin A used in the following examples.
A-1: Sumitomo Chemical Co., Ltd. Tough Selenium H3002 (with MFR = 2 anti-tacking agent), amorphous polypropylene resin (propylene-butene-1 copolymer 95% by weight)
A-2: Tough selenium T3712 manufactured by Sumitomo Chemical Co., Ltd. (MFR = 3 with anti-adhesion agent), amorphous polypropylene resin (propylene-butene-1 copolymer 85% by weight)
A-3: Sun Allomer (manufactured) PM671A (MFR = 7), crystalline block PP
A-4: Bayer LEVAMELT 700, (0% crystallinity, glass transition temperature (Tg) <0 ° C., vinyl acetate 70 wt% MFR = 4)
A-5: Bayer's LEVAMELT 500 (crystallinity 5% glass transition temperature (Tg) <0 ° C., vinyl acetate 50 wt% MFR = 3)
A-6: Evaflex EV260 manufactured by Mitsui DuPont Polychemical Co., Ltd. (crystallinity 20% glass transition temperature (Tg) <0 ° C., vinyl acetate 28 wt% MFR = 6)
(Example 1)

In advance, a low-density polyethylene film (25 μm) was laminated on a biaxially stretched polyethylene terephthalate film (25 μm) by a dry laminating method using a two-component reactive urethane adhesive to prepare a substrate-1. The laminated body was set in the unwinding part of the coextrusion laminating apparatus, and lamination was performed so that the resin A-1 was in contact with the biaxially stretched polyethylene terephthalate film. At that time, an ethylene-hexene-1 copolymer (density 0.920 g / cm ³ , MFR = 4) obtained by a single-site catalyst was used as a coextrusion resin. The processing temperature is 240 ° C. and the processing speed is 50 m / min. It is. The structure of the obtained laminated body is as follows, and the cross-sectional schematic diagram of the structure of this laminated body is shown in FIG.

Low density polyethylene c (25 μm) / urethane adhesive d / biaxially stretched polyethylene terephthalate film e (25 μm) / resin (A-1) f (20 μm) / ethylene-hexene-1 copolymer g (20 μm)
The obtained laminate was sandwiched between the substrates 1 and sealed at 130, 140, 150, and 160 ° C. by heat sealing. The sample was preliminarily created with a biaxially stretched polyethylene terephthalate film (25 μm) / resin A-1, cut into a 25 mm width strip, and then a crosshead speed of 300 mm / min. The initial strength was measured by T-type peeling. The obtained peeled sample was resealed again with finger pressure, and the reseal strength was similarly evaluated. Tables 1 and 2 show the results of performing this operation four times.
(Example 2)

Example 1 is the same as Example 1 except that the resin is changed to A-2.
Example 3

As a comparative example for comparing the performance of the laminate of the present invention,
Example 3 is the same as Example 1 except that the resin is A-3.
Example 4

As a comparative example for comparing the performance of the laminate of the present invention,
Example 1 is the same as Example 1 except that the resin is blended so that A-1 / A-3 = 50/50.
(Example 5)

The same as Example 1, except that the resin was A-4 and the processing temperature was 200 ° C.
Example 6

Example 5 is the same as Example 5 except that the resin is A-5.
(Example 7)

As a comparative example for comparing the performance of the laminate of the present invention,
Example 5 is the same as Example 5 except that the resin is A-6.
(Example 8)

As a comparative example for comparing the performance of the laminate of the present invention,
Example 5 is the same as Example 5 except that a resin prepared by blending A-6 with a dicyclopentadiene tackifier and process oil is used.
Example 9

  Using base material-2 made by dry laminating a biaxially stretched polyethylene terephthalate film (25 μm) / urethane adhesive / aluminum foil (7 μm) as the base material, processed so that resin A is laminated on the aluminum foil Example 1 is the same as Example 1. The substrate-1 was used as the adherend to the ethylene-hexene-1 copolymer. The structure of the obtained laminated body is as follows, and the cross-sectional schematic diagram of the structure of this laminated body is shown in FIG.

Biaxially stretched polyethylene terephthalate film e (25 μm) / urethane adhesive d / aluminum foil h (7 μm) / resin (A-1) f (20 μm) / ethylene-hexene-1 copolymer g (20 μm)
(Example 10)

  Example 9 is the same as Example 9 except that the resin is A-4 and the processing temperature is 200 ° C.

From the table, by using amorphous propylene-butene-1 copolymer or ethylene-vinyl acetate copolymer with high vinyl acetate content, good initial strength and resealing for various substrates without using a tackifier It can be confirmed that the strength is obtained. On the other hand, when a crystalline resin is used (Example 3) or the content of the resin A is small (Example 4), it is confirmed that neither initial strength nor reseal strength is obtained. Moreover, it is confirmed that the initial strength of the ethylene-vinyl acetate copolymer with little vinyl acetate content is good, but the reseal strength cannot be obtained (Example 7). Furthermore, it is possible to give resealing performance by blending a tackifier with this resin, but this is not evaluated this time, although it is subject to the stability of the initial strength due to the sealing temperature, but the above mentioned tackifying There is concern about the problem of agent migration (Example 8).
[Creation of packaging materials]
Example 11

The laminate described in Example 1 was slit to a width of 25 mm and used as a tape having resealability as shown in FIG. The packaging material at this time is: biaxially stretched polyester film (12 μm) / urethane adhesive / biaxially stretched nylon film (15 μm) / urethane adhesive /
It consists of aluminum foil (7 μm) / low density polyethylene (40 μm). When the packaging material was manufactured, the tape was interposed, and the packaging material was attached to the packaging material by heat sealing. This packaging material was cut and opened from the following part, the tape part was opened (initial strength), and the resealability was evaluated several times. As a result, the initial strength and reseal strength were good.
(Example 12)

  Although the same evaluation as Example 11 was performed using the laminated body of Example 4, not only the sealing performance (initial strength) was inferior but also the reseal function could not be provided.

It is a cross-sectional schematic diagram which shows the structure of the tape using the laminated body of the structural examples 1 and 2 as an example of this invention. It is a cross-sectional schematic diagram which shows the structure of the package using the laminated body of the structural example 4 as an example of this invention. It is a cross-sectional schematic diagram which shows the structure of the other package using the laminated body of the structural example 4 as an example of this invention. It is a cross-sectional schematic diagram which shows the structure of the laminated body obtained in Example 1 of this invention. It is a cross-sectional schematic diagram which shows the structure of the laminated body obtained in Example 9 of this invention.

Explanation of symbols

a: Packaging material b: Reseal tape b1: Polyolefin resin (1)
b2: Resin A
b3: Polyolefin resin (2)
b4: Polyester resin c: Low density polyethylene resin d: Urethane adhesive e: Biaxially stretched polyethylene terephthalate film f: Resin A
g: ethylene-hexene-1 copolymer h: aluminum foil

Claims (6)

In a laminate composed of low density polyethylene, urethane adhesive, biaxially stretched polyethylene terephthalate film, amorphous polypropylene resin, ethylene-hexene-1 copolymer ,
The amorphous polypropylene resin, have a tack, wherein the MFR at JIS K 6760 is propylene -α-olefin copolymer of 0.1 to 50 g / 10 min, laminate. The amorphous polypropylene resin, is blended differential scanning calorimeter (DSC) by a single amorphous polypropylene resin having substantially no melting peak and crystallization peak, or the resin 50 wt% or more resins The laminate according to claim 1, wherein the laminate is a composition. The amorphous polypropylene resin, having a variety of substrate layer and adhesive adjacent to at least one, and characterized by having a plurality of times of re-sealing performance, according to claim 1 or 2 Laminated body. The laminate according to any one of claims 1 to 3 , wherein the reseal strength is in a range of 0.1 to 10 N / 25 mm. The laminated body of any one of the said Claims 1-4 is used as a tape which can be resealed, The laminated body characterized by the above-mentioned. The laminated body of any one of the said Claims 1-4 is used as a resealable packaging body, The laminated body characterized by the above-mentioned.