JP3218112B2 - Fine fibrous polyolefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a manufacturing method of the fine fibrous polyolefin down with useful properties. Fine fibrous polyolefin down of the present invention, asbestos substitute,
It is useful for special paper and filter media that require water resistance.

[0002]

2. Description of the Related Art Polyolefin resins are widely available as low-priced synthetic polymers having excellent electrical properties, water resistance, moderate lipophilicity and flexibility. Its use has been diversified by the emergence of pulp that can be dispersed in water and made into paper. Recently, a fine fiber structure made of a resin has been demanded. As the polyolefin resin is made into a highly fine fibrous material, it is possible to expect the addition of a new function while maintaining the conventional properties.

[0003] For example, flash spinning is a well-known method for making fine fibers. However, this method requires a large amount of solvent, a large-scale spinning device, and a high level of skill, and the resulting fibrous material has a small surface area due to an insufficient degree of splitting, although the degree of fineness is advanced. For this reason, for example, there remain defects such as poor dispersion stability, a problem in surface smoothness when making paper, and poor filtration performance.

As described above, with respect to polyolefin resins, satisfactory fibrous materials have not been obtained by any of the methods at present.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention.

That is, the present invention relates to a method for converting polyolefin pulp into water.
And suspended in a volume of 300 kg / cm ^{2 to} 1000 kg / cm ² .
Pass through the small diameter orifice at high speed due to the pressure difference and collide with the vessel wall
The pulp by shearing
The slurry operation is repeated to obtain the slurry suspension.
Canadian-freeness characterized by dehydration
100 ml to 500 ml, weight average fiber length distribution is 100
μm to 1000 μm and fiber diameter 0.1 μm to 10 μm
And a method for producing a fine fibrous polyolefin .

The fine fibrous polyolefin according to the present invention has a fiber diameter in the range of 0.1 μm to 10 μm when observed under a microscope in a state of being dispersed in water.
It is a fine fibrous polyolefin in which polyolefin fibers having a length of 2,000 or more times do not bind and exist as a whole in a random direction. FIGS. 1, 2 and 5 show electron micrographs showing the shape of the fibers of the fine fibrous polyolefin according to the present invention.

If the Canadian-freeness value, the fiber length distribution and the fiber diameter are not in the above ranges, sufficient performance may not be exhibited when a product is produced. Here, the Canadian-freeness (CF) value is an index of dispersion stability in water and filtration performance, and its measurement method is based on JIS P 8121-1976.
Pulp freeness test method, Canadian standard type.

When the fiber length of the fine fibrous polyolefin according to the present invention was measured using a KA-ANI FS-200 type apparatus / method, the weight average fiber length distribution was 100 μm.
１０００1000 μm.

[0010] In addition, the fine fibrous polyolefin down of the present invention
The viscosity of, for those of water 98 wt%, 25 ° C., BL
Mold, rotor No. 4, 20 when measured at 60 rpm
Although it is about 00 to 5000 cps, it is not limited to this range.

[0011] microfibrous polyolefin emissions of the present invention was usually 60% to 98% by weight of water from both sides of the reduction in the ease and logistics costs redispersion, contained in particular 60 wt% to 80 wt% Sheet It has a shape or a granular material.

[0012] How to obtain a fine fibrous polyolefin emissions of the present invention causes firstly suspended raw material polyolefin pulp in water. The pulp concentration of the suspension is preferably from 0.5% by weight to 5% by weight. If the suspension is unstable, the next splitting will be hindered. Therefore, the polyolefin pulp may be appropriately shredded or pulverized, or the suspension may be homogenized and split. It is good to enter. Further, a method of dispersing with a surfactant is also effective. An aqueous suspension of polyolefin pulp is passed through a small diameter orifice at a high speed with a pressure difference of at least 300 kg / cm ² , hitting against the vessel wall and rapidly decelerating to give a strong shear force to the polyolefin pulp. This is repeated to make the polyolefin pulp suspension into a fine fibrous polyolefin suspension.
The larger the pressure difference when passing through the small diameter orifice, the better, but
Consideration of ^{practicality, 300kg / cm 2 ~1000kg / cm} 2 are suitable, fast passed through a small diameter orifice, to Wari繊fibers giving shearing force by rapid deceleration caused to collide with the wall The higher the number of repetitions of the operation, the better,
About 2 to 40 times is appropriate. Next, the obtained fine fibrous polyolefin suspension is dehydrated to reduce the water content to 60% by weight or less.
Obtaining <br/> fine fibrous polyolefin emissions of the present invention as a 98% by weight. The dehydration method is not particularly limited, but a filter press, centrifugal dewatering and the like can be adopted.

[0013] Types of olefins of the raw material polyolefin pulp include ethylene and propylene. Examples of the raw material pulp include "S" manufactured by Mitsui Petrochemical Co., Ltd.
WPE-400 ”(polyethylene fiber),“ SWP
A commercially available product such as "Y-600" (polypropylene fiber) can be used. Further, it is not necessary to limit the kind, grade, etc. of the olefin to one kind, and further, completely different raw materials, for example, polyester, polyamide, cellulose and the like may be mixed according to the use.

Further, in order to re-dispersibility of the fine fibrous polio <br/> Refi emissions of the present invention obtained further improved, it may be added at any process of producing a suitable surfactant.

The dispersion medium is basically water, but may be a mixture of water with a hydrophilic organic solvent such as a monohydric alcohol, a polyhydric alcohol, a ketone or the like.

As a pulp splitting device in the present invention, a high-pressure homogenizer is effective. High pressure homogenizers include, for example, those commercially available as Manton-Gaulin ™ homogenizers. This apparatus includes a high-pressure pump, a valve device for discharging the liquid to be processed from the high-pressure pump at a high pressure, a valve seat device against which the discharged liquid collides, and a circulation flow path of the processing liquid to the high-pressure pump suction side. This type of device and its operation are well known in the literature, such as Chemical Engineering, 13 (5),
86-92, 1976).

[0017]

According to the present invention, usual whole new fine fibrous polyolefin down the production process is not in range of a conventional common sense can not be achieved with thin fibers get spinning technology is provided.

Fine fibrous polio obtained by the present invention
Refin has excellent papermaking properties even though it is made of synthetic fiber, and the paper sheet obtained from the product of the present invention is not only a single product, but also a high performance filtration material and water resistant even when mixed with other materials. Useful as paper.

[0019]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 As raw material polyolefin pulp, Mitsui Petrochemical Co., Ltd.
Using "SWP E-400" (polyethylene fiber) and "SWP Y-600" (polypropylene fiber)
Perform miniaturization of pulp in the apparatus shown in Table 1, to obtain a CF value of fine fibrous polyolefin down, fiber length distribution, fiber diameter was measured as follows. (1) CF value: conforms to JIS P 8121-1976, pulp freeness test method, Canadian standard type. (2) Weight average fiber length: Measured using a KA-ANI FS-200 type apparatus. (3) Fiber diameter distribution: Observed with a microscope. (4) Viscosity ... water 98 wt% of fine fibrous polyolefin down
The viscosity at 25 ° C. was measured with a BL type rotor No. 4 at 60 rpm.

Further, the "SWPE-"
Electron micrographs showing the state of the 400 "fiber are shown in FIGS.
FIGS. 3 and 4 are electron micrographs showing the state of fibers of “SWP E-400” before micronization, and electron micrographs showing the state of fibers of “SWP Y-600” of the present invention after micronization. FIG. 5 shows “SWP Y−
An electron micrograph showing the state of the "600" fiber is shown in FIG.

[0022]

[Table 1]

Test Example "SWP E-400" and "SWP Y-600" are shown in Table 2.
Microfibrous obtained by refining under the conditions shown in polyolefin <br/> to papermaking fin under the following conditions to measure the breaking strength. (1) Evaluation samples: “SWP E-400” and “SW
PY-600 "(2) Processing equipment: Juicer mixer or homogenizer (M-8) (3) Processing conditions: Juicer mixer: 17000 rpm
× 3 minutes (rotational speed is for idle operation) Homogenizer:
500 kg / cm ² × 5 passes or 15 passes (4) Papermaking conditions: Using a “TSS-type standard square sheet machine” manufactured by Toyo Seiki Seisaku-sho, Ltd. and a handmade paper machine, use a 0.1% by weight slurry to make a drum. Dryer temperature 80
C. and make a paper having a basis weight of 200 g / m ² .

[0024]

[Table 2]

[Brief description of the drawings]

FIG. 1 is an electron micrograph (magnification: 100 times) showing the shape of a fiber of a fine fibrous polyolefin according to the present invention.

FIG. 2 is an electron micrograph (magnification: 1000 times) showing the shape of the fibers of the fine fibrous polyolefin according to the present invention.

FIG. 3 is an electron micrograph (magnification: 100 times) showing the shape of the fiber of the polyolefin of FIG. 1 before miniaturization.

FIG. 4 is an electron micrograph (magnification: 1000 times) showing a shape of a fiber of the polyolefin of FIG. 1 before miniaturization.

FIG. 5 is an electron micrograph (magnification: 100 times) showing the shape of another fine fibrous polyolefin fiber according to the present invention.

FIG. 6 is an electron micrograph (magnification: 100 times) showing the shape of the fiber of FIG. 5 before refining.

Claims (1)

(57) [Claims] The method according to claim 1 the polyolefin pulp was suspended in water, which 300kg / cm ² ~1000kg / cm fast passed through a small diameter orifice at a pressure differential of ^2, the pulp by rapid deceleration caused to collide with the wall The operation of applying a shear force is repeatedly performed, and the obtained slurry suspension is dehydrated . The Canadian-freeness value is 100 ml or more.
500 ml, weight average fiber length distribution is 100 μm to 1000 μm
Fine fibers having a diameter of 0.1 μm and a diameter of 0.1 μm to 10 μm
Polyolefin .