JPH0585576A - Reinforced air-permeable packaging material and method for its production - Google Patents

Abstract

PURPOSE:To make a reinforced air ventilating packaging material producible through a single process with an excellent effect of its reinforcing material. CONSTITUTION:A net-like reinforcing material 4 is laid on the upper surface of a satisfactorily gas-permeable base sheet 1, the upper surface of the base sheet 1 and of the reinforcing material 4 is covered with a heat-sealable synthetic resin layer 5 and the base sheet 1, the reinforcing material 4 and the synthetic resin layer 5 are joined together. Crevices 6 exist intermittently in the synthetic resin layer 5 near the bottom areas in contact with the base sheet 1 on the side face of the net-like raised part of the reinforcing material 4 and they serve as the ventilation hole of the packaging material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breathable packaging material used for packaging desiccants, deodorants, fragrances, absorbents of various gases, etc., and particularly to reinforced breathability having strength and heat sealability. The present invention relates to a packaging material and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conventional reinforced breathable packaging material is one in which a heat-sealable synthetic resin layer is laminated on a base material such as paper or non-woven fabric, a reinforcing material is overlaid thereon, and a heat-sealing material is further formed thereon. In order to make a laminated sheet in which possible synthetic resin layers are laminated and to impart air permeability to this laminated sheet, Japanese Patent Publication No. 46-31
Ventilation holes in the heat-sealable synthetic resin layer or reinforcing material of this laminated sheet using a high-temperature roll provided with needle-like protrusions on the surface according to the method described in Japanese Patent Publication No. 746 or Japanese Patent Publication No. 61-11760. I wear it.

[0003]

The conventional reinforced breathable packaging material and its manufacturing method require two steps, that is, the step of laminating the above-mentioned laminated sheet and the step of forming a vent hole, which requires man-hours and costs. Not only does it have the problem of becoming high, but since it receives heat from the high-temperature roll heated above the melting point of the resin that constitutes the reinforced breathable packaging material in the process of forming the ventilation holes, The strength of stretched and strengthened resin is reduced, and the needle-like protrusions on the surface of the high-temperature roll make holes not only in the heat-sealable synthetic resin layer but also in the reinforcing material. Is very low.

An object of the present invention is to solve the above problems and provide a reinforced breathable packaging material which can be manufactured in one step and maintains the reinforcing effect of the reinforcing material, and a manufacturing method thereof.

[0005]

In order to solve the above-mentioned problems, the reinforced breathable packaging material of the present invention has a net-like reinforcing material disposed on the upper surface of a base material sheet having good gas permeability, and the base material sheet. And the upper surface of the reinforcing material is covered with a heat-sealable synthetic resin layer, and the base material sheet, the reinforcing material and the synthetic resin layer are integrally bonded, and the base material sheet on the side of the mesh-shaped convex portion of the reinforcing material part. Is characterized in that cracks are intermittently present in the synthetic resin layer in the vicinity of the bottom that is in contact with and the cracks serve as ventilation parts.

In order to solve the above-mentioned problems, the method for producing a reinforced breathable packaging material of the present invention is capable of heat-sealing a mesh-like reinforcing material on the upper surface of a substrate sheet having good gas permeability. , A synthetic resin having a flow rate of less than MRF20 is supplied from an extruder so as to have a thickness of less than 50% of the thickness of the reinforcing material at a temperature equal to or higher than its melting point, and this synthetic resin layer is formed between the base material sheet and the reinforcing material. By flowing and solidifying in the direction of the base sheet along the unevenness of the surface, the base sheet,
The reinforcing material and the synthetic resin layer are integrally bonded, and cracks are intermittently generated in the synthetic resin layer in the vicinity of the bottom side of the side surface of the mesh-shaped convex portion of the reinforcing material which is in contact with the base material sheet.

[0007]

When the reinforced breathable packaging material of the present invention is produced by the method for producing a reinforced breathable packaging material of the present invention, when a net-like reinforcing material is arranged on the upper surface of the base sheet, the surface thereof has a net-like reinforcing material. The part where the is present forms a convex part, and the part where the net-like reinforcing material is not present forms a concave part. These sheets, in the gap between the rubber roll and the cooling roll installed on substantially the same horizontal plane,
The synthetic resin having a flow rate of less than MRF20 is passed through the upper surface of the rubber roll so as to sequentially contact the lower surface of the cooling roll and near the position where these sheets are in contact with the rubber roll. When the synthetic resin extruding machine has a thickness of less than 50% of the thickness of the reinforcing material at a temperature equal to or higher than its melting point, the synthetic resin layer is formed along the unevenness of the surface of the base material sheet and the reinforcing material. Although it flows toward the bottom and solidifies, the synthetic resin layer flowing into the recess flows along the side surface of the mesh-shaped convex portion formed by the mesh-like reinforcing material and becomes thin as it approaches the bottom portion, and becomes intermittent near the bottom of the side surface of the mesh-shaped convex portion. A fine crack is generated in the. By varying the thickness of the synthetic resin layer within the range of less than 50% of the thickness of the reinforcing material, it is possible to change the size and length of cracks and change the air permeability.

In this case, if the thickness of the synthetic resin layer is 50% or more of the thickness of the reinforcing material, cracks are unlikely to occur near the bottom side of the side surface of the reinforcing material net-like convex portion, and if the thickness is further increased, cracks will occur. Disappear. Further, if the synthetic resin layer has an MRF of 20 or more, the synthetic resin has good fluidity even if the thickness of the reinforcing material is 50% or less. It is difficult to generate cracks.

As described above, the reinforced breathable packaging material of the present invention is processed in one step, has breathability due to the cracked portion, and is reinforced by the net-like reinforcing material.

[0010]

EXAMPLE An example of the reinforced breathable packaging material A of the present invention and a method for producing the same will be described with reference to FIGS.

In FIGS. 1 to 3, the base sheet 1 is
Paper or non-woven fabric with good air permeability, composed of one or more materials selected from pulp, rayon, polyethylene terephthalate, polyamide, polyethylene, polypropylene, etc., gas permeability is JIS-P8117 The air permeability defined by the air quality test method) is 300 seconds or less.

As the reinforcing material 4, one or more materials selected from polyethylene terephthalate, polyamide, polyethylene, polypropylene and the like are usually processed into a film shape and stretched in order to eliminate elongation and increase strength. Reinforce, cut fine fibers into split fibers, process into threads or tapes, weave these as warp 2 or weft 3, or use the adhesive or heat-sealable material at the intersection of warp 2 and weft 3. In the case of, a reticulated sheet fixed by heat bonding is used.

The heat-sealable synthetic resin layer 5 is a simple substance or a complex selected from polyethylene, polypropylene, ethylene / ethylcryl copolymer, ethylene / methylcryl copolymer, ionomer and the like, and its flowability is MF.
R is 20 or less.

The cracked portion 6 exists near the bottom of the side surface of the raised portion of the intersection of the warp yarn 2 and the weft yarn 3 of the reinforcing member 4. Due to the cracked portion 6, the air permeability of the reinforced breathable packaging material A is increased. Is obtained.

As shown in FIG. 3, the reinforcing air-permeable packaging material A is processed by placing the net-like reinforcing material 4 on the upper surface of the base material sheet 1 and the rubber rolls 7 installed on substantially the same horizontal plane. The gap with the cooling roll 8 is passed through so that the upper surface of the rubber roll 7 and the lower surface of the cooling roll 8 are sequentially contacted,
In the vicinity of the position where these sheets are in contact with the rubber roll 7, a synthetic resin which can be heat-sealed and has a flow rate of less than MRF20 is applied to the upper surfaces of these sheets at a temperature of the melting point or higher and a reinforcing material thickness of 50% or more. With a thickness of less than 5%, the synthetic resin layer 5 runs downwards from the T die 9 of the synthetic resin extruder, and the synthetic resin layer 5 is directed toward the base material sheet 1 forming the bottom along the unevenness of the surface of the base material sheet 1 and the reinforcing material 4. Flowing and solidifying, the base material sheet 1, the reinforcing material 4 and the synthetic resin layer 5 are integrally bonded, and the cracked portion 6 is intermittently provided in the vicinity of the bottom side of the side surface of the mesh-shaped convex portion of the reinforcing material 4 in contact with the base material sheet 1. It is intended to occur.

Then, in the vicinity of the position where the base material sheet 1 and the reinforcing member 4 are in contact with the rubber roll 7, the synthetic resin is dripped onto the upper surface of these sheets from the T-die 9 of the synthetic resin extruder. This is because the sheet 1 and the reinforcing member 4 are integrally bonded to the synthetic resin layer 5 while being in close contact with each other.

Further, when the dripped synthetic resin layer 5 flows along the unevenness of the surface of the base material sheet 1 and the reinforcing material 4 and solidifies, if the flow is too good, the synthetic resin layer 5 Flows smoothly on the side surface of the bulge of the reinforcing member 4 and does not generate the crack 6, so that the condition for the crack 6 is as follows.
It is necessary to use synthetic resins with an MRF of less than 20.

If the synthetic resin layer 5 is too thick, cracks 6 will not occur, so the thickness of the synthetic resin layer 5 must be less than 50% of the thickness of the reinforcing material 4.

The rubber roll 7 is made of silicone rubber having a good releasability and is cooled by passing it through a water cooling pipe or the like.

The cooling roll 8 is a metal roll which is also cooled through a water cooling pipe.

The relationship between the position of the rubber roll 7 and the cooling roll 8, the temperature, the gap, and the traveling speed of the sheet is as follows.
Have chosen to come into contact with.

[0022]

EFFECTS OF THE INVENTION The reinforced breathable packaging material of the present invention has the strength of the wrapping material reduced because the conventional reinforced breathable packaging material also perforates the reinforcing material when the vent hole is opened. On the other hand, since there is no hole in the reinforcing material, there is an effect that sufficient strength can be obtained.

Further, the thickness of the synthetic resin layer should be 5 times that of the reinforcing material.
By varying variously within the range of less than 0%, the size and length of the crack can be changed, and desired breathability can be obtained.

The method for producing a reinforced breathable packaging material of the present invention requires two steps as compared with the conventional method for producing a reinforced breathable packaging material, and can be produced in one step, which is a low cost reinforced breathable material. An effect that a packaging material can be obtained is exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the reinforced breathable packaging material of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view showing a method for manufacturing a reinforced breathable packaging material of the present invention.

[Explanation of symbols]

 A Reinforced breathable packaging material 1 Base material sheet 2 Warp 3 Weft 4 Reinforcing material 5 Synthetic resin layer 6 Cracked portion 7 Rubber roll 8 Cooling roll 9 T-die

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 27/06 7258-4F // B29L 9:00 4F

Claims (2)

[Claims] 1. An upper surface of a substrate sheet having good gas permeability,
A net-like reinforcing material is arranged, the upper surface of the base material sheet and the reinforcing material is covered with a heat-sealable synthetic resin layer, and the base material sheet, the reinforcing material and the synthetic resin layer are integrally bonded, There are intermittent cracks in the synthetic resin layer in the vicinity of the bottom that is in contact with the base material sheet on the side of the net-like convex portion of the material part
A reinforced breathable packaging material characterized in that the cracked portion becomes a vented portion. 2. An upper surface of a substrate sheet having good gas permeability,
It is possible to heat seal on the upper surface of the net-like reinforcing material,
A synthetic resin having a flow rate of less than MRF20 is supplied from an extruder so as to have a thickness of less than 50% of the thickness of the reinforcing material at a temperature equal to or higher than the melting point thereof, and the synthetic resin layer is provided on the surface of the base material sheet and the reinforcing material. The base sheet, the reinforcing material, and the synthetic resin layer are integrally bonded by flowing and solidifying in the direction of the base sheet along the irregularities of, and the vicinity of the bottom side of the side surface of the mesh-shaped convex portion of the reinforcing material that is in contact with the base sheet. 2. A method for producing a reinforced breathable packaging material, wherein cracks are intermittently generated in the synthetic resin layer.