JPS61108549A - Laminate - 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 (Field of Industrial Application) The present invention relates to a laminate that prevents odors and tastes from base materials and adhesives from diffusing into package contents.

(Prior art) In recent years, polyolefin resins (hereinafter abbreviated as PO) have been widely used, such as cellophane, polyethylene terephthalate (hereinafter PET), etc.
It is laminated with paper, aluminum (hereinafter abbreviated as M), etc., and used for food packaging, pharmaceutical packaging, etc.

For example, an extrusion coating method in which a base material such as PET is pretreated with an anchor coat, etc., and then low density polyethylene (hereinafter abbreviated as LDPE) is extruded and laminated at high temperature (320°C), Dry lamination method in which LDPE films or sheets pretreated with corona treatment etc. are laminated via adhesive, or LDPE is co-extruded at high temperature (320°C) and low temperature (280°C) and used as a base material such as PET. A method has been used in which layers are stacked on top of each other.

(Problems to be Solved by the Invention) However, in the case of extrusion coating, LDPK is extruded at a very high temperature, so the odor and taste of decomposed LDPE products migrate into the contents. In addition, in the case of dry lamination, the odor caused by the corona treatment or the odor or taste of the adhesive or organic solvent passes through the LDPE and migrates into the contents. Furthermore, in the case of coextrusion molding, high temperatures (
320℃) The odor and taste of the decomposed products from extrusion are reduced at low temperatures (28℃).
(0°C) The odor and taste of the contents, which pass through the extrudate and migrate into the contents, can be a drawback that lowers the commercial value depending on the product.

Particularly recently, in the packaging of mineral water, alcoholic beverages, fruit juices, etc., there has been a desire to use packaging materials with less transfer of odor and taste. If even a small amount of odor is transferred to these products, the commercial value of these products will be significantly reduced, so there is a great demand for improvement.

(Means for Solving the Problem) The present invention aims to meet such requirements by providing a specific gas barrier layer and molding under certain conditions. Out 1. I'm used to it.

That is, the present invention provides "oxygen permeation under dry conditions at 23°C".
GA゛゛°“/m”-24hr°°“J!TV
) lx'<s "- The resin and the substantially odorless polyolefin resin are coextruded at 140 to 290°C, and then the gas barrier resin layer is laminated with the base material to form a thin layered product. A laminate characterized in that the gas barrier resin layer has a thickness of 1 to 30μ and the polyolefin resin layer has a thickness of 10 to 200μ.

(Function) The gas barrier resin used in the present invention has an oxygen permeability of 5 occ/-24 hr-atm or less, preferably 1 occ/i-24 hr-atm or less, particularly preferably 5 CC when dried at 23°C. /FF/ -24hr-at
m or less, for example, saponified ethylene-vinyl acetate copolymers (hereinafter abbreviated as IV and OH), polyvinyl alcohol, polyacrylonitrile resins, polyvinylidene chloride, etc. are preferable.

If the oxygen permeability is other than the above, the effect of the present invention is low and it lacks practicality.

In addition, the substantially odorless PO used in the present invention is specifically, for example, LDPE, high density polyethylene (hereinafter abbreviated as DPE), polypropylene (hereinafter PP), etc.
), ethylene-propylene copolymer, ethylene-α-olefin linear copolymer, ethylene-acrylic acid copolymer (hereinafter abbreviated as EAA), ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA), (abbreviated)).

Here, I am referring to the fact that it melts virtually odorless, and when I smell it, I don't notice any odor, but as an evaluation method, the following sensory test method (hereinafter abbreviated as "method") loses 1 point. It is practical to have less than 100% odor, and it can be said that it is substantially odorless.

That is, the pellets 4Of are collected in a stoppered flask 5001117 and the flask is stoppered, and then heated at 40 tlC for 1 hour. Next, after cooling to room temperature, it was rated according to the ranking proposed by the Tokyo Metropolitan Pollution Research Institute (O: no odor, 1: weak odor, 2: distinct odor, 3: strong odor). The average score (hereinafter abbreviated as points conceded) of the human panelists was used as data.

In the present invention, the gas barrier resin and substantially odorless PO are combined at 140 to 290°C, preferably at 140 to 290°C.
260. Particularly preferably, a two-layer laminate (hereinafter abbreviated as BS layer) is produced by coextrusion molding at a temperature of 140 to 200°C; however, below 140°C, the ductility of the resin is insufficient and film forming performance is lost; If the temperature exceeds 290°C, the odor and taste will overwhelm the odorless PO.

At this time, the thickness of the gas barrier resin is 1 to 30μ, preferably 10 to 20μ, and the thickness of the odorless po is 10 to 30μ.
200μ, preferably Fii s~100 units.

If the thickness of the gas barrier resin is less than 1 μm, odor control will not be achieved, while if it exceeds 30 μm, it will be uneconomical as a packaging material. Moreover, if the thickness of the odorless PO is less than 10 μm, the heat sealing strength will be insufficient, while if it exceeds 200 μm, it will be unfavorable because it will lack economic efficiency.

The BS layer thus obtained is then laminated with the gas barrier resin layer on a base material. The base material is cellophane,
Resin such as PET, nylon or OPP, metal such as M, paper, cloth and PI/M%PE/paper or PK/
The method for bonding paper/PE/At, etc.) and the base material is to co-extrude both sides as they are, or to use a known adhesive such as polyurethane or isocyanate based adhesive depending on the packaging. There are methods such as dry lamination using an adhesive, and methods using soft materials such as LDPE and FAA.

At this time, the B layer surface and the base material surface are subjected to known surface treatments (primer treatment, corona treatment, plasma treatment, etc.),
A substantially odorless adhesive resin extrudable into layer B, e.g.
Pre-containing maleic anhydride-modified polyolefin or the like, or coextruding an adhesive resin such as modified polyolefin onto the B layer surface or base material surface in advance to facilitate lamination. is useful for improving adhesion and lamination processability.

1 (Example) Example 1 Melt Flow Ray) 4.4 f710 min, density 1.1
Ethylene-vinyl acetate coelectrolyte (EVOH) with a 9t/aS ethylene content of 32 molt and melt flow rate) 8
f/10 min, density 0.91 s t/cr 1% and 0 points
．． Using a co-extrusion inflator molding machine equipped with two extruders with a diameter of 65 mm, low-density polyethylene (LDPE) was heated to 215 degrees Celsius, and the LDPE was heated to 215 degrees Celsius.
Coextrusion molding was carried out at a resin temperature of 180° C. and a take-off speed of 30 m/min to create an 88-layer film with an EVOH layer of 15 μm, an LDPE layer of 30 μm, and a total thickness of 45 μm.

On the other hand, the same LDPE as before was extruded at a resin temperature of 320°C through a T-die attached to an extruder with a diameter of 9 (1 m) to form a molten film, which was then subjected to corona discharge surface treatment (30 W-min/min).
FF! ') L7'! :2 o o t/- carton paper was pressed with a pressure roll to obtain a laminated sheet, a laminated base material of LDPE/carton paper.

Here, the LDPE layer was defined as aisμ.

Next, a BS layer was prepared by coating the EVOH layer (B/43 side) of the previous 88-layer film with an isocyanate anchor coating agent (AC) solution and then drying the solvent and coating with a primer. From the T-die attached to the machine, extrude the same LDPK as before at a resin temperature of 320°C to form a molten film, and place this between the B layer surface of the BS layer coated with the primer and the paper surface of the LDpEii-)n paper layer. Sandwich lamination was performed by pressing with a scissor pressure roll as an adhesive. This lamination speed is 8゜7 minutes,
The LDPE layer serving as the adhesive layer had a thickness of 15 μm.

The structure of the obtained laminate was as follows: LDPE (1
5μm 320℃)/Paper/LDPE (15μm 320℃
) /AC/EVOH(1s p -215'C)/L
DPE (30 μm, 180° C.).

Example 2 In place of the 88-layer film consisting of two layers in Example 1, the same EVOH (EVOH, melt flow) 1.
3F/10 minutes, density 0.90? /cl! ! , maleic anhydride-modified low-density polyethylene with a maleic acid content of 0.1% by weight and a K point of 0.3, and the same LDPE as above were processed into EVOH using a coextrusion inflation molding machine equipped with three extruders each having a diameter of 65 mm. Three layers were molded in the same manner as in Example 1 at 21m℃, modified polyethylene at 215℃, and LDPK at 180℃, EVOH 15μ, modified polyethylene 1
An 88-layer film with a total of 60μ was prepared using 5μ and 30μ of LDPE, and in the same manner as in Example 1, starting from the outermost layer, LDPE (15μ)/paper/I, DPE
A laminate having a configuration of (tsμ)/AC/EVOH (xsμ)/modified polyethylene (15μ)/LDPK (30μ) was prepared.

Example 3 In the same manner as in Example 2 except that the thickness of the EVOH layer in Example 2 was changed to 2 μm, LDPE (15 μm) was added from the outermost layer side.
μ)/Paper/LDPE (15μ)/AC/EVOH (2
/j)/denatured po1. lzChile: /(15μ)/LDPE
A laminate having a configuration of (30μ) was created.

Example 4 Using the same method as in Example 2 except that the thickness of the EVOH layer in Example 2 was changed to 1 μm, LDPE (1 μm
5μ)/Paper/LDPK(15μ)/AC/EVOH(1
μ)/modified polyethylene (15μ)/LDPE (30
A laminate having the configuration μ゛) was created.

Example 5 Instead of LDPE in the 88-layer film in Example 2,
Melt flow rate 9 y/x o min, density 0.944
ylcds High-density polyethylene (H
DPK), and in the same manner as in Example 2, except that the same HDPI as above was used in place of I and DPE in the outermost layer,
From the outermost layer, HDPE (15, #)/Paper/LDPE (
A laminate having a composition of 15P 1 /AC/EVOH (15p)/modified polyethylene (15μ)/HDPE (30μ) was created.

Example 6 A similar 88-layer film was made in the same manner as in Example 2. On the other hand, similar LDPE/
A paper laminate was created. Next, the same LDPE was extruded at 320°C from a T-die attached to an extruder with a diameter of 90 mm to form a molten film, and this was used as an adhesive between the paper surface of the previous laminate and M with a thickness of 7 μm. Crimp with scissor crimping roll, sandwich laminate, and LDPE (15
A base material consisting of a laminate of μ)/paper/LDPK(15μ)/At was prepared.

On the other hand, the B layer surface of the iBs layer was prime coated with an isocyanate anchor coating agent.

Next, the same LDPK as before was extruded at 320°C from a T-die attached to an extruder with a diameter of 9 (1 m) to form a molten film, and this was coated with the primer and applied to the B layer side of the 7tBS layer and the M side of the base material. Sandwich lamination was carried out by pressing Id4 as an adhesive with a pressure roll.The lamination speed at this time was 1d 80 m7 minutes, and the thickness of the LDPE layer was ll.
It was set to 115μ. The structure of the obtained laminate is: LDPK(tsμ)/paper/LDPK(1sμ)/from the outermost layer side.
At/LDP E(15P)/AC/EVOH(15
fi),/modified yN "Liethylene (15μ)/LDPE (aoμ).

Example 7 A base material made of the same laminate of LDPK (15μ)/paper/LDPE (15μ)/A/ and EVOH (15μ)/modified polyethylene (15μ) was prepared in the same manner as in Example 6.
A BS layer having a configuration of /LDPE (30μ) was created.

2 Next, apply a primer coat to the B layer side of the BS layer with an isocyanate-based anchor coating agent, apply a primer coat using a polyurethane adhesive, and then dry laminate the B layer side and the M side of the base material, starting from the outermost layer side. ,LDPE(1
5μ)/Paper/LDPE (xsμ)/M/Adhesive/AC/
EVOH (15μ) / modified polyethylene (15μ) /
A laminate of I, DPE (30μ) was prepared.

Example 8 The LDPI resin temperature during coextrusion molding of the 88-layer film in Example 2 was varied from 180°C to 230°C. In the same manner as in Example 2, LDPE (
15μ)/Paper/LDPE (15μ)/AC/EvOH
(15μ) / modified polyethylene (15μ) / LDPE (
A laminate with a thickness of 30 μm was prepared.

Example 9 Instead of the 88 layer film in Example 2, a density of 1.1
ay/a1. L/D using a capillary viscometer
=8/2.1 each day, the shear rate is 3,0005 ec-'', the apparent melt viscosity is s, o o at a temperature of 240°C.

Boy's 6 Nycxno (hereinafter abbreviated as NY) is 240
℃, modified polyethylene at 240℃ and LDPK at 18℃
Three layers were coextruded in the same manner at 0°C, and a total of 75μ was formed using 30μ of Ny, 15μ of modified polyethylene, and 30μ of LDPK.
An 88-layer film of LDPE (15μ)/paper/
A laminate of LDPK (1 sμ)/AC/N5F (30μ)/modified polyethylene (15μ)/LDPE (30μ) was prepared.

Comparative Example 1 LDPE (15μ) was added from the outermost layer in the same manner as in Example 9 except that the thickness of the Ny layer in Example 9 was 20μ.
/Paper/LDPK (15μ)/AC/Ny (20μ)
/ modified polyethylene (ts, u) / LDPE (30μ
) was created.

Comparative Example 2 LD of BS layer film in Example 2 was 0.3
In the same manner as in Example 2, except that LDPE with a K normal point of 2.5 was used instead of PE, LDPE (15
μ)/Paper/LDPE (1sμ)/AC/EVOH(1
sμ)/modified polyethylene (15μ)/LDPE (30
A laminate with μ and K normal point 2.5) was created.

Comparative Example 3 Example 21C: From the outermost layer side, the same method as Example 2 was used except that the LDPE resin temperature was changed to 320°C instead of 180°C when coextruding the BS layer film. L.D.
PE (15μ)/Paper/LDPE (15μ)/AC, /E
VoH (l s, u)/modified polyethylene (15μ)/
A laminate of LDPE (30μ, 320°C) was prepared.

Comparative Example 4 Except for the EVOH layer of the BS layer film in Example 2,
In the same manner as in Example 2 except that the AC agent coating was not applied, LDPE (15μ)/paper/LDPE (ls
door)/modified polyethylene (15μ>/LDPE (30μ
) was created.

<Evaluation> Table 21 shows the results of evaluating the odor and taste of the laminate prepared on each side, as well as the amount of oxygen permeation through the BS layer.

In addition, odor evaluation was performed on one side of 20 laminates of each configuration.
Create a package with ω seals on all sides and fill it with odorless air 2
00CC was poured into the container, heated at 40° C. for 2 hours, allowed to cool for 1 hour, cut off one corner of the container, and conducted an odor sensory test according to the method described above. The evaluation is based on the average score of the seven panelists, and the score is 0: no odor, 1: weak odor,
2...It smells clearly, 3...It smells great)
0 is represented by ◎, 0 to 1 is represented by ○, 1 to 2 is represented by Δ, and 2 to 3 is represented by ×.

1+, the taste evaluation is based on the same packaging as the odor evaluation;
After pouring 200cc of mineral water into it, 23
After standing for 3 days at ℃, a sensory test of the taste of the water was conducted.

The evaluation is based on the average score of the seven panelists, and the score is 0: I don't feel any heat, 1: I feel it weak, 2...
・I feel it clearly, 3...I feel it strongly), and 0
◎, 0 to 1, 01 to 2, Δ, and 2 to 3, ×.

(Effects of the Invention) As can be seen from Table 1, the laminate of the present invention has a remarkable effect of preventing the transfer of odors and tastes caused by base materials and adhesives, and can be easily applied to packaging materials. It is of high practical value.

(Margin below) □〇・

Claims (1)

[Claims] Oxygen permeation amount under drying at 23°C is 50c. c. /m^2・
In a laminate in which a gas barrier resin of 24 hr/atm or less and a substantially odorless polyolefin resin are coextruded at 140 to 290°C, and then the gas barrier resin layer is laminated with a base material, the gas barrier The thickness of the polyolefin resin layer is 1 to 30μ, and the thickness of the polyolefin resin layer is 10 to 2μ.
A laminate characterized by having a thickness of 00μ.