JPH0655485B2 - Paperboard container and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to paperboard laminates,
More particularly, it relates to non-foil paperboard laminates useful for making containers such as fruit or citrus juices, beverages, etc., and non-liquid dry products.
This laminate has the function of protecting the packaged product from loss of essential oils, flavors and vitamins as well as good oxygen barrier properties.

[0002]

BACKGROUND OF THE INVENTION Although low density polyethylene coated paperboard has been used for such purposes, it is not possible to provide an acceptable container and therefore a further barrier material that can reach the desired goals is desired. It is rare. Impermeable materials such as aluminum foil, polar materials such as polyamide, polyethylene terephthalate, polyvinylidene chloride, polyvinyl chloride, etc., and highly crystalline non-polar materials such as high density polyethylene and polypropylene have good gas barrier properties. It is well known to provide various degrees of barrier to absorption and / or permeation of non-polar citrus juice flavor oils such as d-limonene. However, the addition of additional barrier material to such structures complicates the manufacturing process due to the fundamental incompatibility of the paperboard and low density polyethylene with the added material. Nonetheless, polyethylene is the most desirable material to be applied to both the inner and outer surfaces of the laminate to achieve a reliable and easy-to-form heat seal when the container is formed.

US Pat. Nos. 4,789,575 and 4,802,94
No. 3 discloses a laminate structure having inner and outer layers of polyethylene with an additional barrier material and a method of making the same, which requires more complicated manufacturing steps than the present invention, and the structure is reliable. It is not very popular. U.S. Patent No. 4,
513,036 discloses another structure with an inner and outer layer of polyethylene, but the polyethylene barrier material does not exert good efficacy against essential oil and vitamin C loss. Prior art related to the present invention is further described in the following documents: US Pat. No. 4,
No. 289,830 describes a coextruded multilayer film having a barrier structure similar to that used in the present invention; PLASTI
Reprint from CS WORLD (July 1984), “Barrier
plasticschallenge foil "describes a barrier structure applied to paperboard similar to that used in the present invention; 19
1986 TAPPI simultaneous extrusion seminar Marriott Hilton Head, Hi
lton Head, SC, TA filed April 1-3, 1986
The PPI PRESS publication "High Barrier Polymers" also shows a typical film-like barrier structure.

[0004]

OBJECTS OF THE INVENTION It is an object of the present invention to provide an improved heat-sealable foilless laminate for fruit or citrus juices, beverages, etc., and non-liquid dry products that are easy to manufacture and that exhibit reliable efficacy. Is to provide.

[0005]

In one embodiment of the invention, a commercially available structure for a paperboard carton consisting of paperboard sandwiched between two layers of low density polyethylene (LDPE) is selected as the base material. Next, in one manufacturing step, a symmetrical five-layer barrier structure consisting of LDPE / tie layer / EVOH / tie layer / LDPE is coextruded onto the surface of one of the layers of LDPE of the base material. The coextrusion process can be performed without any independent treatment of the LDPE layer of the base material. This is because adjacent LDPE / LDPE interfaces are compatible with each other. In another embodiment of the present invention, a paperboard support is selected and both sides of the paperboard support are flame or corona discharge treated and the outer surface of the paperboard support is extrusion coated with a layer of LDPE, the paperboard support Laminates can be made in-line by extrusion coating a layer of LDPE on the inner surface of a support and coextruding the five layer structure onto the LDPE inner layer of paperboard. The final structure will be constructed with polyethylene on its inner and outer surfaces to provide the most desirable heat sealing properties, but it will be much easier to manufacture than conventional ones. The carton made from the laminate of the present invention has excellent gas barrier protection for dry products, sufficient retention of aroma oils and prevention of vitamin C loss of the contained citrus juices, thereby preserving the product. The deadline is extended.

[0006]

EXAMPLES The present invention will be described in more detail based on examples.

In the preferred embodiment of the invention, the laminate is prepared as follows.

First, both sides of the paperboard support are subjected to flame treatment or corona discharge treatment. A layer of LDPE is then extrusion coated onto one side of the paperboard at temperatures in excess of 600 ° F to achieve good bonding to the paperboard. Next, a layer of LDPE is extrusion coated onto the other side of the paperboard at the same temperature as the first layer. Finally, Pl
One of the first layers of LDPE applied to paperboard with a 5-layer EVOH sandwich sandwiched by exar tie layer and LDPE cover layer
In order to prevent the decomposition of EVOH and tie layer, 600 °
Coextrude at a temperature substantially below F.

The laminate thus formed was arranged so that the five-layer coextrusion was the inner or liquid contact surface of any container made from this laminate, the laminate was marked, cut into blanks and folded. ,
Then, the side seams are heat-sealed as usual.
The blanks made are filled and sealed by conventional equipment in the usual way. In another embodiment, a five-layer sandwich is a two-layer low density polyethylene (L
Direct co-extrusion onto a base material consisting of paperboard sandwiched between DPEs).

Barrier laminates made in accordance with the present invention exhibit excellent barrier properties and meet FDA standards for use in food packaging. In one example, the laminate of the present invention has an outer coating of about 7-12 lbs / strand LDPE; a paperboard of varying thickness (depending on carton size); and an interior of about 7-14 lbs / strand LDPE. With coating; and about 4-7 lbs / strand LDPE, 2-4 lbs
/ Continuous adhesive tie layer (Plexar 177), 4-9 lbs / continuous EVO
H (Eval EP), consisting of 2-4 lbs / continuous tie layer (Plexar 177) and about 4-7 lbs / continuous LDPE product contact layer
A coextruded sandwich layer applied to the LDPE inner coating. The preferred EVOH is Eval EP resin sold by Eval, Inc., USA. A preferred tie layer is Plexar 177 sold by USI. Is commercially available
Any extrusion grade of LDPE is suitable for the present invention. Ream (rea
m) The size is 3000 sheets 25 x 38 inches.

Although EVOH is an excellent oxygen barrier, its efficacy is greatly affected by relative humidity (RH). Therefore, for packaging dry food, the LD adjacent to the coextrusion layer should be used.
The RH sensitivity of EVOH can be reduced by increasing the thickness of the PE layer. This allows the coat weight of the LDPE applied to the paperboard to be varied while maintaining the symmetric coextruded layer within the above limits.

Thus, the laminate of the present invention is
It will be appreciated that it has barrier properties comparable to the most desirable products disclosed in the prior art, yet much easier and easier to manufacture than conventional laminates. Further, it will be appreciated that the coat weights typically shown can be reduced or varied depending on the use application.

The embodiments of the present invention will be described below item by item.
It

(Embodiment 1) (a) Inside of mutually opposite sides
A paperboard support having a front surface and an outer surface; (b) a heat shield coated on the outer surface of the paperboard support.
Layer Lumpur Low density polyethylene polymer; ◆ (c) Hitoshi coated on the inner surface of the paperboard substrate
(D) the heat shield applied to the inner surface of the paperboard support.
Of low-density polyethylene polymer
Released heat-sealable low-density polyethylene polymer
Layer, tie layer, heat sealable ethylene vinyl alcohol
Copolymer layer, tie layer and heat sealable low density
Product contact inner sand toy consisting of polyethylene polymer layer
A paperboard container formed from a laminate containing a touch layer .

(Embodiment 2) The product contact inner sand
Embodiment 1 characterized in that the switch layer is symmetrical
Mounted paperboard container.

(Embodiment 3) Heat of about 7 to 12 lbs / ream
Low-density polyethylene polymer with sealability supports the paperboard
An embodiment characterized in that it is applied to the outer surface of the body
The paperboard container described in 2.

(Embodiment 4) Heat of about 7 to 14 lbs / ream
Low-density polyethylene polymer with sealability supports the paperboard
An embodiment characterized in that it is applied to the inner surface of the body
The paperboard container described in 3.

(Embodiment 5) The product contact inner sand
The switch layer is about 4-7 lbs / strand of low density polyethylene,
2-4 lbs / ream tie layer, 4-9 lbs / ream ethylene
Vinyl alcohol copolymer, 2-4 lbs / strand
Layers and about 4-7 lbs / strand of low density polyethylene
The paperboard container according to the fourth embodiment, wherein

(Embodiment 6) The tie layer is a Plexar type
A plate according to embodiment 5, which is a binder material.
Paper container.

Embodiment 7 Improved Gas Barrier
Properties and migration of essential oils, flavors and vitamins
Sealable Paperboard With Improved Resistance To
A method of manufacturing a laminate, wherein (a) flame treatment is applied to the inner surface and outer surface of the paperboard support.
And, ◆ (b) a ratio of about 7 to 12 lbs / with the outer surface of the paperboard substrate
Extruded layer of low-density polyethylene polymer
Over and coating, ◆ (c) the ratio of about 7 to 14 lbs / with the inner surface of the paperboard substrate
Extruded layer of low-density polyethylene polymer
Computing and, ◆ (d) about 4 to 7 lbs / ream of low density polyethylene, 2 to 4 l
bs / ream adhesive tie layer, 4-9 lbs / ream ethylene vinyl
Nyl alcohol copolymer, 2-4 lbs / strand adhesive
From nappe layer and 4-7 lbs / strand of low density polyethylene
An inner surface of the paperboard support comprising a symmetric sandwich layer
Applied to the outer surface of the polyethylene polymer layer
Extruding at a time, ◆ A method characterized by comprising each step.

Embodiment 8 The adhesive tie layer is Pl
Embodiment 7 which is an exar type adhesive material
How to list.

Embodiment 9 Improved Gas Barrier
Properties and migration of essential oils, flavors and vitamins
Sealable Paperboard With Improved Resistance To
A method of manufacturing a laminate, wherein: (a) about 7 to 12 lbs / strand of heat applied to the outer surface of the laminate.
Sealing layer of low density polyethylene polymer and its inner surface
Approximately 7 to 14 lbs / strand heat sealable on the surface Low density
Paperboard base material having a layer of polyethylene polymer
, (B) About 4-7 lbs / strand of low density polyethylene, 2-4 l
bs / ream adhesive tie layer, 4-9 lbs / ream ethylene vinyl
Nyl alcohol copolymer, 2-4 lbs / strand adhesive
Nag layer and low density polyethylene of about 4-7 lbs / strand
A symmetric sandwich layer comprising an inner surface of the paperboard support.
The outer surface of the layer of polyethylene polymer applied to a surface
Co-extruding, ◆ A method characterized by comprising each step.

[Brief description of drawings]

1 is a cross-sectional view of a laminate of the present invention.

FIG. 2 is a block diagram showing a method for manufacturing a laminate according to the present invention.

FIG. 3 is a block showing another method of manufacturing a laminate according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B65D 81/24 D 9028-3E // B29K 23:00 4F B29L 9:00 4F

Claims (3)

[Claims] 1. A paperboard support having opposite inner and outer surfaces; (b) a layer of heat-sealable low density polyethylene polymer coated on the outer surface of the paperboard support; (c). A layer of heat-sealable low-density polyethylene polymer coated on the inner surface of the paperboard support; and (d) coextruded on the outer surface of the heat-sealable low-density polyethylene polymer applied to the inner surface of the paperboard support. A heat-sealable low density polyethylene polymer layer, a tie layer, a heat sealable ethylene vinyl alcohol copolymer layer, a tie layer and a product contact inner sandwich layer comprising a heat sealable low density polyethylene polymer layer. Paperboard container. 2. An essential oil with improved gas barrier properties,
A method of making a heat-sealable paperboard laminate having improved flavor and vitamin migration resistance, comprising: (a) flame treating the inner and outer surfaces of the paperboard support; and (b) the paperboard support. The outer surface is extrusion coated with a layer of heat sealable low density polyethylene polymer at about 7-12 lbs / ream, and (c) the inner surface of the paperboard support has a heat sealable low density polyethylene at about 7-14 lbs / ream. Extrusion coated with a layer of polymer, (d) about 4-7 lbs / strand of low density polyethylene, 2-4 l
A symmetrical sandwich layer consisting of bs / strand adhesive tie layer, 4-9 lbs / strand ethylene vinyl alcohol copolymer, 2-4 lbs / strand adhesive tie layer and 4-7 lbs / strand low density polyethylene. A method comprising co-extruding onto the outer surface of the polyethylene polymer layer applied to the inner surface of the paperboard support. 3. An essential oil with improved gas barrier properties,
A method of making a heat-sealable paperboard laminate having improved flavor and vitamin migration resistance, comprising: (a) about 7-12 lbs / strand of heat-sealable low density polyethylene polymer applied to its outer surface. And a layer of heat-sealable low density polyethylene polymer at about 7 to 14 lbs / strand applied to its inner surface, and (b) at about 4 to 7 lbs / strand. Density polyethylene, 2-4 l
bs / strand adhesive tie layer, 4-9 lbs / strand ethylene vinyl alcohol copolymer, 2-4 lbs / strand adhesive tie layer and about 4-7 lbs / strand low density polyethylene symmetrical sandwich layer Is co-extruded onto the outer surface of the layer of polyethylene polymer applied to the inner surface of the paperboard support.