JPH11291419A - Cloth sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a transparent sheet being light in weight, intensive in strength, and having visible inside by laminating an ethylene.α-olefin copolymeric layer on one or both surfaces of a cloth of an ethylene.α-olefinic composition of a specific quantity manufactured in use of a catalyst having specific properties and a high density resin composition having a specific density. SOLUTION: An ethylene.α-olefinic copolymer is manufactured by the use of a metallocene catalyst having properties of a melt-flow rate of 0.3-30 g/10 mn, a density of 0.90-0.94 g/cm<3> , a minimum peak temperature of 80-125 deg.C by DSC, a molecular weight distribution (Mw/Nn) of 1.8-3.5, and a melt tension of 0.5-4 g. After that, this is woven or knitted by 50-90 wt.% by the use of flat yarn as warp and weft, which is made of resin composition consisting of 10-50 wt.% high density polyethylene with a density of 0.945 g/cm<3> so as to form cloth, and finally, an ethylene.α-olefin copolymeric layer is formed on one surface or both surfaces thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth sheet, and more particularly, to a cloth sheet used for a base fabric for a flexible container.

[0002]

2. Description of the Related Art As a base fabric for a flexible container,
A cloth sheet in which a film made of polyvinyl chloride or the like is laminated on a cloth made of nylon or polyester fibers is frequently used. These cloth sheets maintain high strength and flexibility by using multifilaments such as nylon and polyester fibers, and form a laminated sheet by laminating highly flexible polyvinyl chloride. However, polyvinyl chloride has the drawback that the specific gravity is high and the entire sheet becomes heavy and the workability is poor, and there is a problem of bleeding of the plasticizer and the generation of toxic gas during incineration. Therefore, when trying to laminate a light-weight polyolefin having no problem of toxic gas, there is a problem that the adhesion between the multifilament such as nylon and polyester and the polyolefin is inferior and sufficient peel strength cannot be obtained.

[0003] In recent years, a cloth sheet in which a polyolefin layer is laminated on one or both sides of a cloth woven by using a lightweight, excellent moldable and inexpensive polyolefin flat yarn as a weft yarn has been widely used. A cross sheet in which low density polyethylene or linear low density polyethylene is laminated on one side or both sides of a cloth obtained by using a flat yarn made of high density polyethylene having excellent drawing effect and high strength as a weft is well known. Have been. However, in the base fabric for a flexible container, high welding strength and high peeling strength are required at the welded portion of the sheet, but a cross sheet layer made of high-density polyethylene and a laminate layer made of low-density polyethylene or linear low-density polyethylene are required. Peel strength was not sufficient. Further, the strength of the flat yarn is liable to decrease due to the heat when laminating the laminate layer on the cloth and the heat deterioration due to the heat welding when forming into a flexible container using the cloth sheet, and further improvement has been demanded.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a cross sheet which is lightweight, high in strength, excellent in flexibility, excellent in peel strength, and excellent in resistance to rubbing.

[0005]

According to the present invention, 50-95% by weight of high-density polyethylene having a density of 0.945 g / cm ³ or more is provided in order to technically solve the above problems.
5 to 50% by weight of an ethylene / α-olefin copolymer produced using a metallocene catalyst having the properties of
On one or both sides of a cloth woven using a flat yarn formed using a resin composition consisting of a warp yarn on one side or both sides, a cross sheet provided with the ethylene / α-olefin copolymer layer is provided. This is to solve the above problem. (1) Melt flow rate is 0.1 to 30 g / 10 mi
n. (2) Density 0.90 to 0.94 g / cm ³ (3) Maximum peak temperature (Tm) by DSC of 80 to 1
25 ° C (4) Molecular weight distribution (Mw / Mn) is 1.8 to 3.5 (5) Melt tension is 0.5 to 4 g

[0006]

DETAILED DESCRIPTION OF THE INVENTION The high-density polyethylene used in the present invention has a density of 0.945 g / cm ³ or more,
Using a known Ziegler catalyst or the like, an ethylene homopolymer or an ethylene having 3 to 12 carbon atoms produced by a known process such as a slurry method, a solution method or a gas phase method.
-In olefin copolymers and mixtures thereof, specific α-olefins include propylene, 1-butene,
4-methyl-1-pentene, 1-hexene, 1-octene, 1-dodecene and the like can be mentioned. Its density is 0.945
It is preferably in the range of ~0.980g / cm ^3, a melt flow rate (hereinafter abbreviated as MFR) of 0.1 to 50 g / 10
min., preferably in the range of 0.5 to 30 g / 10 min.

The ethylene / α-olefin copolymer produced by using the metallocene catalyst used in the present invention is:
An ethylene / α-olefin copolymer comprising ethylene having the following properties (1) to (5) and an α-olefin having 3 or more carbon atoms.

(1) MFR is 0.1 to 30 g / 10 mi
n, but 0.1 for flat yarn forming applications
10 to 10 g / 10 min., Preferably 0.5 to 5 g / 10 min.
min. is more preferable. MFR is 0.1g / 10mi
If it is less than n., molding processability is inferior, and if it exceeds 10 g / 10 min., high strength cannot be obtained even if the stretching ratio is increased, which is not preferable. Also, 5 to 5 for lamination to cloth
30 g / 10 min. Is preferable, and 10 to 20 g / 10 min.
min. is more preferable. If the MFR is less than 5 g / 10 min., The molding processability for lamination is inferior, and 30 g / 10 m
If it exceeds in., the peel strength is undesirably reduced.

(2) Density is 0.90 to 0.94 g / c
m ³ , preferably 0.91 to 0.93 g / cm ³ . If the density is less than 0.90 g / cm ³ , the stretchability is inferior and the welding strength is reduced, and if it exceeds 0.94 g / cm ³ , the flexibility is undesirably reduced.

(3) The maximum peak temperature (T
m) is from 80 to 125 ° C, preferably from 90 to 120 ° C. If the maximum peak temperature (Tm) by DSC is less than 80 ° C, the difference from the stretching temperature is too small, and if it exceeds 125 ° C, the optimal stretching temperature is too high, which is not preferable.

(4) The molecular weight distribution (Mw / Mn) is 1.8
To 3.5, preferably 2.2 to 3.0. Mw / Mn
If it is less than 1.8, the moldability is poor, and if it is 3.5 or more, the stretchability is poor, which is not preferable.

(5) a melt tension of 0.5 to 4 g,
Preferably it is 1.0 to 3 g. Melt tension is 0.
If it is less than 5 g, the molding stability of the flat yarn is inferior and 4 g
Those exceeding the above are difficult to manufacture.

The process for producing the ethylene / α-olefin copolymer is described in JP-A-58-19309 and JP-A-5-19309.
JP-A-9-95292, JP-A-60-35005, JP-A-60-35006, JP-A-60-35
No. 007, JP-A-60-35008, JP-A-60-35009, etc., by copolymerizing ethylene and an α-olefin using a metallocene catalyst.

The above-mentioned metallocene catalyst is, for example, bis (cyclopentadienyl) zirconium dichloride (Cp
2ZrCl2) and a catalyst composed of a co-catalyst such as a metallocene compound represented by methylaluminoxane (MAO).

The metallocene compound includes a ligand having a cyclopentadienyl ring, a substituted cyclopentadienyl ring substituted with an alkyl group, an indenyl ring, and the like, and hydrogen, a halogen atom, an alkyl group, and the like having zirconium, titanium, Compounds bonded to transition metals such as hafnium, and specific examples thereof include bis (cyclopentadienyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dichloride, and bis (ethylcyclopentadienyl) zirconium dichloride. , Bis (cyclopentadienyl) titanium dichloride, bis (methylcyclopentadienyl) titanium dichloride, bis (ethylcyclopentadienyl) titanium dichloride, bis (cyclopentadienyl) hafnium dichloride, bis (methyl) Cyclopentadienyl) hafnium dichloride, bis (ethyl cyclopentadienyl)
Hafnium dichloride and the like can be mentioned.

An aluminoxane or boron compound can be used as a co-catalyst for the metallocene compound. As the aluminoxane, usually, a chain or cyclic aluminoxane produced by bringing a trialkylaluminum into contact with water is preferable. Representative methylaluminoxane (MAO) can be obtained by reacting trimethylaluminum with water. The metallocene catalyst can be used by being supported on an inorganic oxide or the like.

The polymerization method is not particularly limited, and it is produced by a high pressure method, a solution method, a gas phase method, a slurry method or the like.

The α-olefin copolymerized with ethylene includes α-olefins having 3 or more carbon atoms, for example, propylene, 1-butene, 1-pentene, 1-hexene,
-Octene, 4-methyl-1-pentene and the like. Of these, one or two or more α-olefins are added in an amount of 5 to 50% by weight, preferably 10 to 30% by weight,
It is preferable to copolymerize with 50 to 95% by weight, preferably 70 to 90% by weight of ethylene.

The mixing ratio of the high-density polyethylene to the ethylene / α-olefin copolymer produced using the metallocene catalyst is 50 to 50%.
5 to 5% by weight of a 95% by weight ethylene / α-olefin copolymer
0% by weight, preferably 80% high density polyethylene.
~ 90 wt%, ethylene / α-olefin copolymer is 1
0 to 20% by weight. If the high-density polyethylene is more than 95% by weight, the adhesiveness decreases, the peel strength is insufficient, the flexibility is poor, and the weaving deterioration rate due to yarn cracking during weaving increases. It is not enough and is inferior in strength and not preferable.

In the present invention, a flat yarn is formed by melt-extruding a mixture of the above-mentioned ethylene / α-olefin copolymer and high-density polyethylene as a raw material by using an extruder, and forming a film by a T-die method or an inflation method. After the film is cooled and solidified, the film is slit, re-heated to a temperature at which it can be stretched, stretched, and then heat-treated to form a flat yarn. The stretching temperature is preferably from 70 to 120C, more preferably from 80 to 110C. If the stretching temperature is lower than 70 ° C., whitening occurs or the stretchability decreases, and if it exceeds 120 ° C., the stretchability decreases, which is not preferable. The stretching ratio is preferably 5 to 12 times, more preferably 8 to 10 times. If the draw ratio is less than 5 times, the strength becomes insufficient, and if it is more than 12 times, yarn cracks occur, which is not preferable. As a heating method at the time of stretching, any method such as a hot roll method, a hot plate method, an infrared method, and a hot air method can be adopted. The single yarn fineness of the flat yarn is preferably 500 to 5000 denier (hereinafter abbreviated as d), and more preferably 1000 to 3000 d. If the single yarn fineness is less than 500 d, the mechanical strength of the base fabric for a flexible container is not sufficient. If it exceeds 5000 d, not only the weaving efficiency is lowered, but also the flexibility is poor, which is not preferable.

The flat yarn is woven using warp yarns to form a cloth. As a weaving method, weaving can be performed using a known loom such as a circular loom, a sluser loom, and a water jet loom. Various shapes such as plain weave, twill weave and leno weave are applied as the weave structure.

In the present invention, an ethylene / α-olefin copolymer layer produced by using the metallocene catalyst is provided on one or both sides of the cloth to form a cross sheet. When it is used as, it is preferable to provide it on both sides. Ethylene ・ α
Examples of a method for laminating the olefin copolymer layer include a dry lamination method and a calendering lamination method, and a known extrusion lamination method is preferably used. The thickness of the layer provided by the extrusion lamination method is 30
To 150 μm, more preferably 50 to 100 μm. If it is less than 30 μm, the welding strength in post-processing will be insufficient, and if it exceeds 150 μm, the weight will increase and the flexibility will be lost, which is not preferable.

In forming the ethylene / α-olefin copolymer layer, other polyethylene resins may be used in combination without departing from the spirit of the present invention. As other polyethylene resins, low-density polyethylene by a high-pressure radical method usually used for extrusion lamination,
Examples include linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer, and the like.

The polyethylene resin used in the present invention includes an antioxidant, a lubricant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent, a pigment within a range not departing from the gist of the present invention depending on the purpose of use. Further, additives such as an inorganic filler, an organic filler, a crosslinking agent, a foaming agent, and a nucleating agent may be blended.

[0025]

EXAMPLES Test method 1. Maximum peak temperature (Tm) by DSC: JISK7
121 molecular weight distribution (Mw / Mn): GPC method 3. Melt tension: Measured by a melt tension tester manufactured by Toyo Seiki Co., Ltd. (measuring temperature 190 ° C.) 4. Tensile strength: JISZ1651 5. Tensile elongation: JISZ1651 Compliant 6. Tear strength: Conforms to JISZ1651 7. Peel strength: Two substrates are superimposed and the end is 4
Over a width of 0 mm, the welding temperature is 31
0, 365, 390 ° C, pressure 2kg /
m2, welding speed 2.1m / min, width 30
mm and cut it into a test piece.
With a gripping distance of 150 mm and a pulling speed of 50 mm / min, 18
The peeling was performed at 0 degree. 8. Fir resistance test: A fir test is performed in accordance with JISZ1651 (Scott method), and cracks, damage, and other abnormalities on the surface when the number of fir times is 1,000 are visually determined.
Good was evaluated as 、, and poor was evaluated as ×.

Comparative Example 1: High-density polyethylene (MFR =
1.0 g / 10 min., Density = 0.961 g / cm ³ , T
m = 132 ° C.), a film is formed by an inflation method, cooled, slit and stretched at 115 ° C.
A flat yarn having a fineness of 2,000 d was obtained by drawing 6.8 times by a hot plate contact drawing method at 120 ° C. and an annealing temperature of 120 ° C. Using the flat yarn as the warp yarn, a plain weave cloth was obtained at a driving density of 15 × 15 yarns / inch. On both sides of the cloth, a linear low-density polyethylene (MFR =
8.0 g / 10 min., Density = 0.917 g / cm ³ , T
m = 124 ° C.) at a melt extrusion temperature of 280 ° C. by extrusion lamination to provide a 70 μm thick laminate layer to obtain a cross sheet. The obtained cloth sheet was inferior in peeling strength and was not preferred for use in flexible containers. Table 1 shows the evaluation results.

Comparative Example 2: A low-density polyethylene (MFR = 12.0 g / 1) was applied to both sides of the cloth used in Comparative Example 1.
0 min., Density = 0.916 g / cm ³ , Tm = 105
C) at a melt extrusion temperature of 300 ° C. by extrusion lamination to provide a 70 μm-thick laminate layer to obtain a cross sheet. The obtained cross sheet deteriorated in mechanical properties due to thermal deterioration during lamination, had poor peeling strength, and had cracks on the surface in a rubbing resistance test, which was not preferable for a flexible container. Table 1 shows the evaluation results.

Example 1: High density polyethylene (MFR =
1.0 g / 10 min., Density = 0.961 g / cm ³ , T
m = 132 ° C.) 85% by weight of an ethylene / α-olefin copolymer (MFR = 2.5 g / 1) with a metallocene catalyst
0 min., Density = 0.926 g / cm ³ , Tm = 121
C., Mw / Mn = 2.5) Using a mixture with 15% by weight, a film was formed by an inflation method, cooled, slit, stretched at 115 ° C., and annealed at 1
20 ° C, fineness of 20 with 6.8 times stretching by hot plate contact stretching
00d flat yarn was obtained. Using the flat yarn as the warp yarn, a plain weave cloth was obtained at a driving density of 15 × 15 yarns / inch. On both sides of the cloth, an ethylene / α-olefin copolymer (MFR = 19 g / 10 min., Density = 0.915) produced using a metallocene catalyst
g / cm ³ , Tm = 101 ° C., Mw / Mn = 2.8) at a melt extrusion temperature of 270 ° C. by an extrusion lamination method to a thickness of 70 mm.
A cross sheet was obtained by providing a laminate layer having a thickness of μm. The obtained cloth sheet was excellent in mechanical properties, peel strength, and resistance to rubbing, and was suitably used for flexible containers. Table 1 shows the evaluation results.

Comparative Example 3: High density polyethylene (MFR =
1.0 g / 10 min., Density = 0.961 g / cm ³ , T
m = 132 ° C.) and an ethylene / α-olefin copolymer (MFR = 2.5 g / 1) using 40% by weight of a metallocene catalyst
0 min., Density = 0.926 g / cm ³ , Tm = 121
C., Mw / Mn = 2.5) The same procedure as in Example 1 was carried out except that a mixture with 60% by weight was used. The obtained cross sheet was excellent in peel strength and resistance to rubbing, but was inferior in mechanical properties and was not preferred for use in flexible containers. Table 1 shows the evaluation results.

Comparative Example 4: On both sides of the cloth used in Example 1, a linear low-density polyethylene (MFR = 8.0 g)
/ 10 min., Density = 0.917 g / cm ³ , Tm = 1
(24 ° C.) at a melt extrusion temperature of 290 ° C. by an extrusion lamination method to provide a 70 μm-thick laminate layer to obtain a cross sheet. The obtained cloth sheet was inferior in mechanical properties and peel strength, and was not preferred for use in flexible containers. Table 1 shows the evaluation results.

[0031]

[Table 1]

[0032]

As described above, according to the present invention, a flat yarn made of a resin composition containing a high-density polyethylene and a specific ethylene / α-olefin copolymer in a specific ratio is used as a warp yarn. A cross sheet with a specific ethylene / α-olefin copolymer layer provided on one or both sides of a cross made from a cross, which has excellent flat yarn molding stability, low-temperature extrusion characteristics, and low-temperature adhesiveness, and thus is laminated. And the thermal degradation during flexible container processing and molding can be suppressed, and as a result, a cross sheet that is excellent in mechanical strength, tear strength, peeling strength, and resistance to rubbing and is preferably used for flexible containers can be obtained. I was able to.

Claims (1)

[Claims] 1. A high-density polyethylene having a density of 0.945 g / cm ³ or more, 50 to 95% by weight, and the following (1) to
A flat yarn formed using a resin composition comprising 5 to 50% by weight of an ethylene / α-olefin copolymer produced using a metallocene catalyst having the properties of (5) is woven using a warp yarn. A cloth sheet comprising the above-mentioned ethylene / α-olefin copolymer layer on one or both sides of the cloth. (1) Melt flow rate is 0.1 to 30 g / 10 mi
n. (2) Density 0.90 to 0.94 g / cm ³ (3) Maximum peak temperature (Tm) by DSC of 80 to 1
25 ° C (4) Molecular weight distribution (Mw / Mn) is 1.8 to 3.5 (5) Melt tension is 0.5 to 4 g