JPH0662794B2 - Method for producing porous film or sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a porous film or sheet, and an object thereof is to provide a supple and tough texture with good leakproofness and moisture permeability. To provide a film or sheet. More specifically, it relates to a method for producing a porous film or sheet from a composition comprising linear low density polyethylene or / and polypropylene, a filler and chlorinated paraffin.

[Conventional technology and problems]

It has been widely practiced to knead a polyolefin resin with a filler and melt-form it to stretch a film or sheet uniaxially or biaxially. In these films or sheets, uniaxial stretching causes a problem that tear strength in the stretching direction and tensile stress in the transverse direction are extremely weak due to anisotropy due to molecular orientation. Further, in the biaxial stretching, although the strength problem can be solved, there is a problem that the stretchability is remarkably deteriorated. In order to solve these problems, the same type of low melting point polymer, rubber-like material (natural rubber, isoprene rubber, butadiene rubber), olefin thermoplastic elastomer, styrene thermoplastic elastomer, liquid rubber, etc. are added to polyolefin resin. A method of doing so has been proposed, but none has yet been found to be satisfactory.

[Means for solving problems]

The present inventors have improved the drawbacks of such a porous film or sheet, while having flexibility, in uniaxial stretching, the breaking strength in the transverse direction, the elongation, the tear strength in the longitudinal direction are significantly improved, Excellent stretchability in biaxial stretching,
Moreover, as a result of intensive studies aimed at providing a porous film or sheet capable of forming continuous pores at a low magnification, the present invention has been reached.

That is, the present invention is a porous film characterized by stretch-molding a film or sheet obtained by melt-molding a composition containing linear low-density polyethylene or / and polypropylene, a filler and chlorinated paraffin. The present invention relates to a sheet manufacturing method.

Hereinafter, the present invention will be described in more detail. In the present invention, a polyolefin resin selected from linear low density polyethylene and polypropylene is used, but it is supple and tough in order to achieve the object of the present invention. Therefore, linear low density polyethylene is most desirable. Other polyolefin resins may be added to the linear low density polyethylene and / or polypropylene used in the present invention within the range not impairing the features of the present invention. Examples of the polyolefin resin include monoolefin polymers and copolymers such as ethylene, propylene and butene, for example, high density polyethylene, low density polyethylene, crystalline ethylene-propylene block copolymer, polybutene, ethylene-vinyl acetate copolymer. And mixtures thereof.

As the filler, inorganic and organic fillers are used, and as the inorganic filler, calcium carbonate, gypsum, talc,
Carbon black, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, calcium phosphate, aluminum hydroxide, zinc oxide, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide,
Alumina, mica, asbestos powder, shirasu balloon, zeolite, silicate clay, cement, silica fume, mica powder and the like are preferable. As the organic filler, wood powder, coal powder, pulp powder, etc. are used, and these may be used alone or as a mixture.

The average particle size of the filler is preferably 30 μm or less, 10 μm
m or less, more preferably 0.5 μm to 5 μm.

The surface treatment of the filler is important for uniform dispersibility in the resin, and the surface treatment agent is preferably one that can make the surface hydrophobic such as fatty acid or its metal salt.

Chlorinated paraffin used in the present invention has a chlorine content of 1
~ 65 wt% is preferred, more preferably 35% -55
% Is used. Such a chlorinated paraffin is produced by a known method, for example, by passing chlorine gas into molten solid paraffin, n-paraffin or a carbon tetrachloride solution of solid paraffin.

The introduction of linear low-density polyethylene or / and polypropylene (hereinafter abbreviated as polyolefin resin) and chlorinated paraffin into the filler gives the preferable result of significantly improving the compatibility of the two. The introduction of such chlorinated paraffins improves the uniform dispersibility of the filler in the resin, improves the anisotropy of the obtained film or sheet, that is, significantly improves the transverse strength and the tear strength in the uniaxial stretching. Connect Further, when biaxially stretched, more excellent stretchability is exhibited.

When blending the polyolefin resin, filler and chlorinated paraffin, the blending ratio is 20 to 400 parts by weight of filler and 1 to 10 parts of chlorinated paraffin per 100 parts by weight of polyolefin resin.
0 parts by weight is preferred. When the blending ratio of the filler is less than 20 parts by weight, continuous porosity is not sufficiently formed in the stretched film or sheet, resulting in low porosity. On the other hand, if it exceeds 400 parts by weight, the dispersibility in the polyolefin resin becomes poor and the strength after stretching is lowered. In the present invention, a more preferable blend is a filler 60 to 100 parts by weight of the polyolefin resin.
200 parts by weight and 10 to 50 parts by weight of chlorinated paraffin.

To uniformly mix the polyolefin resin, filler and chlorinated paraffin, for example, use a single-screw extruder, a twin-screw extruder, a mixing roll, a Banbury mixer, a twin-screw kneader, etc. You can At that time, if necessary, generally used antistatic agent, stabilizer, ultraviolet absorber, dye, pigment,
You may mix additives, such as.

Regarding the molding of the film or sheet, an inflation method using a circular die or a T die method using a T die may be appropriately used. Regarding stretching, roll stretching is used in uniaxial stretching, and either single-stage stretching or multi-stage stretching may be performed. In the biaxial stretching, a tenter method is used, and either sequential stretching or simultaneous stretching may be used. Both uniaxial stretching and biaxial stretching
Stretching of 1.2 times or more is preferable.

〔The invention's effect〕

A feature of the method of the present invention is that it can be stretched at room temperature, and at the same time, a uniformly whitened film or sheet having continuous pores can be obtained at a low magnification. This stretched film or sheet is excellent in the improvement of anisotropy by uniaxial stretching, and the strength in the transverse direction and the tear strength in the longitudinal direction are remarkably improved. This shows that biaxial stretching is also useful, and biaxial stretching is easy because the anisotropy is small.

Of course, it is possible to perform heat treatment to stabilize the dimensions after stretching. It is also possible to perform surface treatment such as corona treatment by a known method.

The film or sheet obtained by the method of the present invention,
Due to its flexibility and toughness, it may be used for various purposes. For example, clothing articles, medical materials, hygiene materials, filtration filters, battery separators and the like can be mentioned.

Further, by using a filler of a metal salt such as Ca, Al or Mg as a filler, a Cl gas at the time of incineration is trapped and becomes an inactive inorganic substance, so that a Cl gas is hardly generated, a pollution countermeasure is taken.

〔Example〕

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

Example 1 100 parts by weight of a linear low-density polyethylene resin (Ultzex 3010F manufactured by Mitsui Petrochemical Co., Ltd.), 150 parts by weight of surface-treated calcium carbonate (average particle size 1 μm), and chlorinated paraffin (chlorine content 45%) 30 The parts by weight were thoroughly kneaded with a mixing roll, pulverized and pelletized. This is Japan Steel Works Ltd.
A T-die was attached to a manufactured P40-22AB type single-screw extruder, and a film was formed at a resin temperature of 180 ° C to obtain a film having a thickness of 70 µm. This was uniaxially stretched 2.0 times. The test method is as follows.

Strong elongation test According to JIS K-6301.

(No. 3 dumbbell type, tensile strength 300 mm / min) Tear test According to JIS D-8116.

Moisture permeability Conforms to JIS Z-0208.

The stretchability was judged as follows.

No break, uniform whitening stretch 4 No break, some stretch unevenness 3 No break, stretch unevenness 2 Break, no stretch 1 Examples 2 to 5 Other than stretching ratio 1.8 times, 1.5 times, 1.2 times and 2.5 times A stretched film was obtained in the same manner as in Example 1.

Example 6 The same as Example 1 except that 15 parts by weight of chlorinated paraffin was used.

Example 7 The same as Example 1 except that 40 parts by weight of chlorinated paraffin was used.

Example 8 100 parts by weight of calcium carbonate and 30 parts of paraffin chloride
The same as Example 1 except that the parts by weight are used.

Example 9 The same as Example 1 except that calcium carbonate was 75 parts by weight and chlorinated paraffin was 30 parts by weight.

Examples 10 and 11 The same as Example 1, except that polypropylene (Nobelen FL6S, manufactured by Mitsubishi Petrochemical Co., Ltd.) was used as the polyolefin resin, the stretching temperature was 80 ° C., and the stretching ratios were 2.0 times and 2.3 times.

Example 12 The same as Example 1 except that polypropylene / linear low-density polyethylene = 5/5 was used as the olefin resin and the stretching temperature was 80 ° C.

Examples 13 and 14 Same as Example 1 except that kaolin and clay were used as the filler.

The results of the above Examples 1 to 14 are shown in Table 1.

Comparative Examples 1 to 3 100 parts by weight of linear low-density polyethylene (Ultzex 3010F, manufactured by Mitsui Petrochemical Co., Ltd.) was used as the polyolefin resin, and 150 parts by weight of surface-treated calcium carbonate was used as a filler at a stretching temperature of 100 ° C. Draw ratio 4.0 times, 5.0 times,
The procedure is the same as in Example 1 except that the value is 6.0 times.

Comparative Example 4 The same as Comparative Example 1 except that the draw ratio was 2.0 times.

Comparative Example 5 The same as Comparative Example 1 except that the stretching ratio was 2.0 and the stretching temperature was 80 ° C.

Comparative Examples 6 to 8 100 parts by weight of linear low-density polyethylene (Ultzex 3010F, manufactured by Mitsui Petrochemical Co., Ltd.) was used as the polyolefin resin, and 150 parts by weight of surface-treated calcium carbonate (average particle size μm) was added as the filler. Stretching temperature using 30 parts by weight of liquid paraffin (Chuo Kasei Co., Ltd., Para Para 350S) as an agent
Same as Example 1 except that the draw ratio was 80 times, 2.0 times, 3.0 times and 3.5 times.

Comparative Example 9 Comparative Example 6 is the same as Comparative Example 6 except that a hydrogenated polybutadiene having hydroxyl groups at both ends (GI-2000, manufactured by Nippon Soda Co., Ltd.) was used as an additive and the stretching temperature was 50 ° C.

Comparative Example 10 The same as Comparative Example 6 except that liquid polyisoprene rubber (Kuraray Isoprene Chemical Co., Ltd., LIR-30) was used as an additive and the stretching temperature was 50 ° C.

Comparative Example 11 As an additive, EPDM (manufactured by Sumitomo Chemical Co., Ltd., Esplen 552
The same as Comparative Example 6 except that () was used.

The results of Comparative Examples 1 to 11 are shown in Table 2 above.

Examples 15 to 17 Iwamoto Seisakusho Co., Ltd. biaxial stretching machine (BIX-701) 2 at a time
Axial stretching is (1.2 × 1.2) times, (1.5 × 1.5) times, (2.0
The same procedure as in Example 1 was carried out except that the stretching temperature was 80 ° C.

Examples 18 to 20: Coaxial biaxial stretching (1.2 × 1.2) times at a stretching temperature of 80 ° C, (1.
The procedure is the same as in Example 1 except that 5 × 1.5) times and (2.0 × 2.0) times are performed.

Comparative Example 12 Same as Comparative Example 1 except that biaxial stretching (BIX-701) manufactured by Iwamoto Seisakusho Co., Ltd. (BIX-701) was used to perform biaxial stretching (1.5 × 1.5) times at a stretching temperature of 100 ° C. .

Comparative Example 13 Comparative Example 6 except that coaxial biaxial stretching was carried out at a stretching temperature of 100 ° C.
Is the same as.

The results of Examples 15 to 20 and Comparative Examples 12 and 13 are shown in Table 3 above.

Front page continuation (72) Inventor Kaori Takimoto 695 Minamihata, Wakayama, Wakayama

Claims (5)

[Claims] 1. A linear low density polyethylene or (and)
A method for producing a porous film or sheet, which comprises subjecting a film or sheet obtained by melt-molding a composition containing polypropylene, a filler and chlorinated paraffin, to stretch molding. 2. A compounding ratio of the composition is 20 to 400 parts by weight of filler and 1 to 100 parts by weight of chlorinated paraffin per 100 parts by weight of linear low-density polyethylene or (and) polypropylene. The manufacturing method according to the item. 3. The method according to claim 1, wherein the chlorine content of the chlorinated paraffin is 1 to 65% by weight. 4. The production method according to claim 1, wherein the stretch forming is uniaxial stretching of at least 1.2 times or more. 5. The production method according to claim 1, wherein the stretch molding is biaxial stretching of at least 1.2 times or more.