JP2002067249A - Laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated sheet made of a polyethylene terephthalate and with excellent productivity, high tenacity and excellent heat resistance and stiffness. SOLUTION: The laminated sheet prepared by forming a coating layer on at least one face of a base fabric prepared by weaving and knitting drawn yarns formed by using the polyethylene terephthalate by means of an extrusion lamination method using a composition consisting of polyethylene terephthalate, a polyolefin and a compatibilizer is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laminated sheet,
More specifically, it is a laminated sheet made of polyethylene terephthalate having excellent heat resistance and stiffness, and is suitably used for a flexible container, a tent sheet, a self-supporting container, and the like.

[0002]

2. Description of the Related Art Conventionally, as a raw material of a flexible container, a tarpaulin obtained by laminating polyvinyl chloride or the like on a base cloth made of nylon or polyester fiber has been frequently used.
However, the laminated polyvinyl chloride is liable to be stained by bleeding of a plasticizer, and has a drawback that toxic gas is generated during incineration. Further, even when laminating a polyolefin in place of polyvinyl chloride, there is a problem that the adhesion between nylon and polyester and the polyolefin is poor and sufficient peel strength cannot be obtained.

Therefore, in recent years, a laminated sheet in which the same type of polyolefin layer is laminated on a base fabric made of a drawn polyolefin yarn using a polyolefin having excellent filament formability and a high strength drawn yarn is obtained. However, polyolefin is inferior in heat resistance. For example, since a high-temperature product cannot be directly filled in a polyolefin flexible container using the laminated sheet, a raw material for a flexible container having more excellent heat resistance is demanded. Was.

Further, a laminated sheet made of polyolefin has a low stiffness, and if a cubic sorted collection container or the like is produced using this laminated sheet, it is inferior in self-sustainability and shape retention and cannot be used as a container. Was.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a laminated sheet made of polyethylene terephthalate which is high in strength, heat resistance, and excellent in stiffness. And

[0006]

In order to achieve the above object, a laminated sheet according to the present invention is provided on at least one surface of a base fabric formed by weaving and knitting a drawn yarn made of polyethylene terephthalate.
It has a configuration in which a coating layer is formed by extrusion lamination using the following composition. (Composition) (a) 50 to 90% by weight of polyethylene terephthalate (b) 5 to 45% by weight of polyolefin (c) Epoxy group-containing ethylene copolymer, carboxylic acid or its anhydride group-containing olefin copolymer, styrene At least one selected from the group consisting of thermoplastic elastomers
Seed 5-45% by weight (however, (a) + (b) + (c) = 100% by weight)

[0007]

DETAILED DESCRIPTION OF THE INVENTION The polyethylene terephthalate (PET) used in the present invention is obtained by polycondensing terephthalic acid or its derivative as an acid component and ethylene glycol as a glycol component. Further, one obtained by replacing part of terephthalic acid with a copolymer component may be used. Examples of such a copolymerization component include isophthalic acid, adipic acid, and 2,6-naphthalenedicarboxylic acid as part of terephthalic acid.

Further, as the polyethylene terephthalate, a polyethylene terephthalate beverage container (commonly called a PET bottle) is crushed, and re-pelletized recycled polyethylene terephthalate can be used in place of part or all of the polyethylene terephthalate. Recycled polyethylene terephthalate can be used by adjusting the intrinsic viscosity (η value) reduced by water absorption, heat history, or the like in the repelletization step by solid phase polymerization.

The PET for forming a drawn yarn used in the present invention
Has an intrinsic viscosity (η value) of preferably 0.3 to 1.1 dl / g, more preferably 0.5 to 1.0 dl / g, and more preferably 0.7 to 0.7 dl / g.
9 dl / g is most preferred. Η for forming drawn yarn
If the value is less than 0.3 dl / g, the formability is not easy, and it is difficult to obtain a drawing effect. If the value exceeds 1.1 dl / g, the formability of the drawn yarn is reduced. The η value of PET used as the component (a) of the composition for forming a coating layer is preferably from 0.7 to 1.3 dl / g, and more preferably from 0.9 to 1.1 dl / g.
1 / g is more preferred. When the η value is less than 0.7 dl / g, neck-in is large and the ear portion becomes unstable due to the film swaying phenomenon, and when it exceeds 1.3 dl / g, the drawdown property is undesirably lowered.

In the present invention, polyolefin (PO) used as component (b) of the composition for forming a coating layer
Are specifically high-density polyethylene, linear low-density polyethylene, low-density polyethylene, metallocene-catalyzed ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer. Examples include polyethylene resins such as coalesced resins, and polypropylene resins such as polypropylene, propylene-ethylene block copolymers, and propylene-ethylene random copolymers. Of these, low-density polyethylene is preferable. These may be used alone or in combination of two or more. The melt flow rate (MFR) of PO is preferably 1 to 30 g / 10 min,
3 to 10 g / 10 min is more preferable.

In the present invention, the component (c) of the composition for forming a coating layer may be an epoxy group-containing ethylene copolymer, a carboxylic acid or its anhydride group-containing olefin-based copolymer, or a styrene-based thermoplastic elastomer. At least one selected one is used.

The above-mentioned epoxy group-containing ethylene copolymer comprises:
A copolymer of ethylene and an ethylenically unsaturated carboxylic acid glycidyl ester or a multi-component copolymer obtained by copolymerizing an ethylenically unsaturated compound with the copolymer, specifically,
Examples include an ethylene-glycidyl methacrylate copolymer, an ethylene-glycidyl acrylate copolymer, an ethylene-glycidyl methacrylate-methyl acrylate terpolymer, and an ethylene-glycidyl methacrylate-acrylonitrile / styrene graft copolymer.

The carboxylic acid or olefin copolymer containing an acid anhydride group thereof includes polyolefins such as low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer, polypropylene, and maleic acid. Or a copolymer obtained by grafting an anhydride thereof, fumaric acid, itaconic acid or an anhydride thereof, crotonic acid or an anhydride thereof, or a multi-component copolymer of ethylene with the carboxylic acid or an anhydride thereof and an ethylenically unsaturated compound. Polymers, specifically, maleic anhydride-modified low-density polyethylene, maleic anhydride-modified ethylene-vinyl acetate copolymer, maleic anhydride-modified polypropylene, ethylene-maleic anhydride-methyl acrylate terpolymer And the like.

The styrene-based thermoplastic elastomer is
Polystyrene as a hard segment, polyisoprene or polybitadiene or an ethylene-butene copolymer as a soft segment, or a hydrogenated product thereof, and commercial products such as "Clayton D",
"Clayton G" (trade name: manufactured by Shell Chemical Co., Ltd.), "HIBLER", "Septon" (trade name: manufactured by Kuraray Co., Ltd.), and the like.

In the present invention, the composition ratio of the composition for forming the coating layer is 50 to 90% by weight of component (a), 5 to 45% by weight of component (b), and 5 to 45% by weight of component (c). (However, (a) + (b) + (c) = 100% by weight)
Preferably, component (a) is 60 to 80% by weight, and component (b) 1
0 to 30% by weight, and component (c) 10 to 30% by weight (provided that (a) + (b) + (c) = 100% by weight).
If the compounding ratio of the component (a) is less than 50% by weight, it is difficult to achieve the heat resistance and the stiffness, which are the objects of the present invention.
If it exceeds 0% by weight, neck-in and film swinging phenomena are large during extrusion lamination, and the moldability is poor, which is not preferable.
The component (b) in the composition has a large effect of mainly improving the neck-in in the extrusion laminating method and reducing the film swing phenomenon, and the component (c) is a compatibilizer, and the components (a) and (b) It has the effect of improving workability or impact resistance by improving the compatibility with.

The MFR of the above composition at 280 ° C. is 1
10 to 10 g / 10 min, preferably 2 to 8 g / 10 mi
n is more preferred. If the MFR is less than 1 g / 10 min, the drawdown property is inferior. If the MFR exceeds 10 g / 10 min, the film swing phenomenon becomes large and the moldability becomes unstable. Also,
The melt tension of the composition at 280 ° C is 1 to 10
g is preferable, and 3-7 g is more preferable. If the melt tension is less than 1 g, neck-in is large, and the ear portion becomes unstable due to the film swaying phenomenon, and if it exceeds 10 g, the drawdown property is undesirably reduced.

Furthermore, in the present invention, polyethylene terephthalate for forming a drawn yarn may be extruded with respect to modification such as prevention of longitudinal cracking of a flat yarn and prevention of weaving deterioration, or extrudability and extrudability of a composition for forming a coating layer. In order to improve the formability such as neck-in and film shake phenomenon prevention in the laminating method, within the range that does not essentially impair the characteristics of the present invention,
Thermoplastic resins such as polyolefin, polyamide, and polystyrene can be appropriately mixed. Of these, polyolefins which are easy to handle and inexpensive are preferred.

Specific examples of the polyolefin include polypropylene, high-density polyethylene, and linear low-density polyethylene, and polypropylene is preferred. As the polypropylene, any of propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer, and the like can be used, and one of these may be used alone, or two or more may be used in combination. The melt flow rate (MFR) of propylene is 1
３０30 g / 10 min, preferably 3、３10 g / 10 m
in is more preferred.

The mixing ratio of the thermoplastic resin is preferably 1 to 50% by weight, more preferably 5 to 20% by weight, based on polyethylene terephthalate. If the blending ratio is less than 1% by weight, the effect of blending another resin cannot be obtained, and
Exceeding the weight percent is undesirable because the properties of the present invention are lost.

Further, in the present invention, in order to improve the vertical crack, the formability, the lubricity, the surface appearance, and the like of the drawn yarn, as long as the characteristics of the present invention are not essentially impaired, An inorganic filler can be blended with polyethylene terephthalate. As the inorganic filler, calcium carbonate, talc, silica, clay, hydrotalcite and the like are preferably used. Of these, calcium carbonate is preferred. The blending amount of the inorganic filler is preferably 0.5 to 10% by weight based on polyethylene terephthalate.
~ 5 wt% is more preferred. If the amount is less than 0.5% by weight, it is difficult to achieve the above object. If the amount is more than 10% by weight, the flexibility of the drawn yarn is lost and the yarn breaks.

For the thermoplastic resin used in the present invention, an antioxidant, an ultraviolet absorber, a light stabilizer, a lubricant, an antistatic agent, a pigment, a flame retardant, a crosslinking agent, a foaming agent, a nucleating agent and the like are added. Agents can be added to the extent that the properties of the present invention are not substantially impaired.

In the present invention, the drawn yarn may be formed by a known production method using the above-mentioned polyethylene terephthalate, and it is sufficient that the drawn yarn has a high tenacity due to the drawing effect. As the form of the drawn yarn, any of a monofilament, a multifilament, a flat yarn, a split yarn and the like can be used, and a multifilament and a flat yarn are preferable in terms of moldability, flexibility and high strength. Is most preferred.

As a method for producing the flat yarn, specifically, a raw material composed of polyethylene terephthalate is extruded at a melting temperature of preferably 260 to 290 ° C.
To form a film by the inflation method or the T-die method, and after cooling and solidifying, stretching by slitting and performing relaxation heat treatment to obtain a flat yarn. The stretching is usually preferably performed in two steps. The first step is performed 3 to 6 times at 60 to 120 ° C, and the second step is performed 2 to 3 times at 150 to 200 ° C.
A relaxation heat treatment is performed at 80 to 220 ° C.

The raw material polyethylene terephthalate is heated at 150 to 160 ° C. using a drier before being fed into the extruder.
And drying for 4 to 5 hours.

The fineness of the drawn yarn is 500 to 50.
00 dtex (dt) is preferable, and 1000 to 3000
dt is more preferred. If the fineness is less than 500 dt, the mechanical properties such as tensile strength are insufficient as the base fabric, resulting in 5000 dt
If it exceeds, the flexibility is inferior and the adhesion to the coating layer is insufficient, which is not preferable.

The drawn yarn is woven and knitted using the warp yarn to form a base fabric. The driving density is preferably 5 to 40 fibers / 2.54 cm, more preferably 10 to 20 fibers / 2.54 cm.
The basis weight of the base fabric is 100 to 500 g / m ^2.
Is preferable, and 150 to 300 g / m ² is more preferable.
Various shapes such as plain weave, twill weave, entangled weave, and mosaic weave are used as the weave structure of the woven fabric, and the knitted fabric may be either flat knit or warp knit, and specifically, tricot knit, Miranese knit, Russell Knitting and the like.

A coating sheet is formed on at least one surface of the base fabric obtained as described above by an extrusion lamination method using the above-described composition to obtain a laminated sheet. In the extrusion lamination method, the melting temperature is 260 to 290 ° C.
It is preferable that the surface temperature of the cooling roll is 10 to 50 ° C.

The thickness of the coating layer is 30 to 200
μm is preferable, and 50 to 150 μm is more preferable. Contact
When the thickness of the adhesion layer is less than 30 μm, the adhesive strength becomes insufficient.
Above, poor abrasion resistance is not preferable, and exceeds 200 μm
This increases the load and increases the rigidity, which is not preferable.
The basis weight of the laminated sheet is 150 to 800 g / m. ²
Is preferred, and 200 to 500 g / m²Is more preferred.

Before providing a coating layer on at least one surface of the base fabric by the extrusion laminating method, it is preferable that the surface of the base fabric is subjected to a surface treatment such as a corona discharge treatment or a plasma treatment in order to improve adhesion.

The laminated sheet obtained as described above is
It is excellent in heat resistance, strong in stiffness, and excellent in tensile strength due to strong peeling strength between the base fabric and the coating layer, and can be directly filled with a high-temperature product as a flexible container, and is suitably used for the purpose. Further, for a tent sheet, it is preferably used because it has a strong peeling strength against fluttering by wind and the like. Furthermore, it can be suitably used as a stiff, self-supporting container, such as a cubic sorted collection container.

[0031]

As described above, the laminated sheet of the present invention uses a specific composition containing polyethylene terephthalate as a main component on at least one surface of a base fabric formed by weaving and drawing a drawn yarn made of polyethylene terephthalate. It is a structure in which the coating layer is formed by extrusion lamination method.It is a sheet with excellent productivity, heat resistance, and stiffness, and the base fabric and the coating layer are the same type of polyester. Since it is a resin, it has excellent adhesiveness, and thus a sheet having high peel strength and high tensile strength can be obtained. When this laminated sheet is used as a base material in a flexible container, it is suitably used for specific applications in which a high-temperature product can be directly filled. In addition, the laminated sheet is cut and sewn by making use of the characteristic of strong stiffness, and has an effect of being excellently used as a self-supporting container such as a cubic separated collection container having excellent shape retention.

[0032]

EXAMPLES Example 1 Polyethylene Terephthalate (η)
= 0.8 dl / g) using a dryer at 150 ° C.
After drying for 5 hours, the extruder was used to extrude at a melting temperature of 270 ° C.
The film was cooled by a chill roll cooling method using a die to form a film, and the cooled and solidified film was slit into a width of 8 mm, and the first-stage stretching was performed at 90 ° C. at a magnification of 4 times, and then the second-stage stretching was performed at 190 ° C. After stretching at a magnification of 2 times at 200C, a relaxation heat treatment was performed at 200C to form a flat yarn having a fineness of 2000 dt. The obtained flat yarn has a tensile strength of 3.6c.
N / dt and elongation were 10.0%. Using the above-mentioned flat yarn, a plain-woven base fabric was formed at a driving density of 14 × 14 / 2.54 cm. The basis weight of the base fabric was 220 g / m ² . Next, as the coating layer composition, 70% by weight of polyethylene terephthalate (η = 1.0 dl / g), 15% by weight of low-density polyethylene (MFR = 8.0 g / 10 min), ethylene-glycidyl methacrylate-methyl acrylate ternary A composition comprising 15% by weight of a copolymer was prepared. The MFR of this composition at 280 ° C. is 4.5.
g / 10 min, and the melt tension at 280 ° C. was 5 g. After corona discharge treatment on both sides of the base fabric, the coating composition was extruded by extrusion lamination using an extrusion temperature of 290 ° C, a cooling roll surface temperature of 30 ° C, and a thickness of 5 mm each.
Lamination was performed at 0 μm to obtain a laminated sheet. The weight per unit area of the laminated sheet was 330 g / m ² , and the tensile strength was 1460 N / 5 cm. A flexible container was obtained by sewing the laminated sheet. This flexible container made of polyethylene terephthalate had high strength and heat resistance, and was able to be directly filled with a synthetic resin product at 100 ° C., and was suitably used.

Example 2: 70% by weight of polyethylene terephthalate (η = 1.0 dl / g), low density polyethylene (MFR = 8.0 g / 10 mi)
n) 15% by weight, styrene-based thermoplastic elastomer (trade name: Clayton G, manufactured by Shell Chemical Co., Ltd.) 15
The procedure was performed in the same manner as in Example 1 except that the composition consisting of% by weight was used. The tensile strength of the laminated sheet is 1480N / 5cm,
As a flexible container, high strength, heat resistance, and the ability to directly fill a synthetic resin product at 100 ° C. were used suitably.

Example 3 A flat yarn was formed from a composition comprising 50% by weight of polyethylene terephthalate (η = 0.8 dl / g) and 50% by weight of recycled polyethylene terephthalate (η = 0.6 dl / g). Was performed in the same manner as in Example 2. The obtained laminated sheet had a tensile strength of 1320 N / 5 cm, and was suitably used for a tent sheet.

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Claims (1)

[Claims] 1. A laminated sheet comprising a base fabric formed by weaving and knitting a drawn yarn made of polyethylene terephthalate on at least one surface of which a coating layer is formed by an extrusion lamination method using the following composition. (Composition) (a) 50 to 90% by weight of polyethylene terephthalate (b) 5 to 45% by weight of polyolefin (c) Epoxy group-containing ethylene copolymer, carboxylic acid or its anhydride group-containing olefin copolymer, styrene At least one selected from the group consisting of thermoplastic elastomers
Seed 5-45% by weight (however, (a) + (b) + (c) = 100% by weight)