JPS60255108A - Porous permeable film and its production - Google Patents

Abstract

PURPOSE:To obtain the titled porous permeable film having excellent strength, resistance to heat and chemicals, and permeability by adding a specified substance to poly-4-methylpentene-1 or poly-3-methylbutene-1, and forming the film. CONSTITUTION:10-90wt%>=15C aliphatic or alicyclic compd. is added to a homopolymer of poly-4-methylpentene-1 or poly-3-methylbutene or a copolymer contg. <=40wt% 2-12C alpha-olefin as a copolymerizable constituent, and the mixture is uniformly mixed. The drawing is carried out between 60 deg.C and the glass transition temp., and the film is biaxially drawn by >=3X3 times at 50%/sec drawing velocity. The porous permeable film, having >=2kg/mm.<2> tensile strength and >=1X10<-6>mlcm/sec m<2>cmHg permeability coefficient to gaseous nitrogen, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a porous permeable film and a method for producing the same. Specifically, the present invention provides a novel porous permeable film that has high strength and high permeability, as well as good heat resistance and chemical resistance, and a method for producing the same.

[Prior art] As a typical example of a porous permeable film, a synthetic resin is mixed with a liquid or solid that is more easily extracted by a solvent, etc. than the synthetic resin, and after being molded into a film, the mixed liquid or solid is mixed into the synthetic resin. There is a method for producing a porous film in which solids are extracted with a solvent, etc., but in order to increase permeability, it is necessary to increase the amount of liquid or solid mixed in as described above to increase the porosity after extraction treatment. However, as a result, defects occur that make the film brittle and easy to break, making it difficult to obtain a practical porous film from the viewpoint of the balance between strength and permeability. A possible method for improving the strength of this film is to stretch the film before or after the extraction treatment, particularly biaxial stretching.

On the other hand, among polyolefin-based resins, poly(Hiromethylpentene-/(TPX)) has excellent heat resistance, electrical properties, chemical resistance, and solvent resistance, so it is used in packaging, insulating containers, etc.
Its uses, such as sheets, are being expanded. In addition, poly-3-methylbutene-/ has better heat resistance, chemical resistance, and solvent resistance than TPX, and if a high-strength porous permeable film can be obtained using these resins, it will be useful in various fields. It is expected that it will become a transparent film.

However, compared to polypropylene, which has the same molecular structure, this type of polymer has a rigid molecular structure and is not flexible, making it difficult to produce uniform stretched films as is normally done with many polymers. is difficult.

For this reason, it is currently difficult to manufacture and supply porous permeable films with an excellent balance of strength and permeability. This method uses a copolymer obtained by copolymerizing a vinyl compound or the like as a copolymerization component. However, in order to obtain sufficient uniform stretchability, it is necessary to increase the copolymerization component), which results in a drastic drop in the melting point and glass transition temperature of the crystal. As a result, the heat resistance, which is the greatest feature of both polymers, deteriorates. Furthermore, chemical resistance is also significantly reduced.

[Purpose of the invention]

In view of the above-mentioned circumstances, the present inventors used poly-damethylpentene-/or poly-3-methylbutene-7 to create a material with excellent strength, heat resistance, and chemical resistance, as well as excellent permeability. With the aim of providing porous and permeable films (including thick films and so-called sheets), as a result of extensive research, we decided to add a specific substance to poly-damethylpentene-/or poly-3-methylbutene-/. It has been discovered that a good porous and permeable film can be obtained without impairing the above-mentioned properties of poly-dameterpentene-/or poly-3-methylbutene-7 by forming a film using the same methods, and in order to complete the present invention. This is what we have come to.

[Structure of the invention]

The gist of the invention is that poly-damethylpentene/or poly-
It is made of 3-methylbutene-7 and has a tensile strength of 0 (Kg).
/ff1I++2) or more and nitrogen gas permeation -6--
1 Porous permeable film 0 characterized by a coefficient of 80×10 (Boo, cdo, Hg) or more and (A) poly-damethylpentene-/or poly-3-methylbutene-7 resin 10-90 Based on weight%, (B) is a solid at room temperature selected from aliphatic compounds and alicyclic compounds (A
) Resin used as component 4- A film-like body is formed from a resin composition consisting of 90 to 10% by weight of an extractable component with a lower melting point, and the film-like body is biaxially stretched, followed by extraction treatment of component (B). The present invention provides a method for producing a porous permeable film, which comprises carrying out a step or biaxial stretching after extraction treatment of component (B).

Poly-damethylpentene-7 or poly-
As 3-methylbutene-/(component (A)), it is possible to use the respective homopolymers as well as copolymers obtained by copolymerizing α-olefins having 0 to 2 carbon atoms as copolymerization components.

Specifically, ethylene, propylene, butene-11hexene-/, tamethylbentene-/, J-methylbutene-/,
Examples include octene/styrene, vinylcyclohexane, etc., and the content of these copolymerized components in the polymer is preferably at most 20% by weight, preferably at most 20% by weight.

The aliphatic compound or alicyclic compound (component (B)) to be added to the above poly-damethylpentene-l or poly-3-methylbutene-/(component (A)) must meet the following requirements: can be mentioned. ■It has good compatibility with polyolefin resin, ■It is solid at room temperature because it is easy to handle when molded into a film, and ■It is soluble in water, lower alcohol, or a mixture of these, which are easy-to-handle solvents. (2) The polymer of component (A) must be in a liquid state when crystallized and solidified. By using the component (B) having these properties, the film using the composition of the present invention can be stretched before the component (B) is extracted, but after the extraction,
Even if it is stretched, it can be stretched uniformly. The reason for this is that component (B) not only plasticizes the polymer that is component (A), but also that component (B) is present in liquid form during the cooling and crystallization stage, causing the crystals to be finely dispersed. This is presumed to be due to the fact that it has the effect of increasing stretchability, resulting in improved stretchability.

As the component (B) that satisfies the above requirements, the number of carbon atoms/! Aliphatic compounds having hydroxyl groups at r or more are preferred. Specific examples include cetyl alcohol (OH, (OH', ), 4
0H, OR), heptadecyl alcohol (OH, (OH
2),, OH, OH), Steary/L/7 Alcohol (OH.

Alcohols such as OH, OH); Dioctyl ether (
(CsH+t)201, didecyl needle ((o, .H
g+)2o), didodecyl ether ((o1□H2s)
2o), dioctadecyl ether ((c+5Hst)2
Ethers such as methyltetradecylketone (O
H,00(OH,),, OH,), n-propylhexadecylketone (OH, (OR,), Co(OH,),
.

OH,), didodecyl ketone (0H3(OH,),
00(OH,), OH,), dioctadecyl ketone (
Ketones such as "a (OH2)uoo(cHi)u'OJ ); octyl laurate (OH, (OHz) n00
0(OH2), 0H31, palmitic acid/l/
(OH, (OH2), 40000H, 0Hs), butyl stearate (aH, (oH,),.

Coo('0H2)30H,), octyl stearate (0HI(0''g)Isooo(OHz)yOHa)
○ (A) ), (B) A method of uniformly mixing both components is usually a method using a known mixing machine such as a twin-screw extruder, Prabender mixer, Banbury mixer, etc. ) Both components are mixed in powder form f (B)
By raising the temperature to a temperature above the melting point of the component, the (A) with the (B) component
If the components are wetted and then fed to the mixer, uniform mixing will be achieved efficiently, making it difficult to create a raw film for making a stretched film, and the raw film after being cooled and solidified will also be brittle. It can only be obtained as a product, cannot be handled, and cannot be used as a product. Also, the amount of component (B) is 7
If it is less than 0% by weight, uniform stretching will be difficult.
A) The proportion of components should be 10-90% by weight.

A normal forming method can be used to prepare a stretched film. Specifically, T-die roll, inflation molding, press molding, etc. are used. The raw fabric obtained in this way can be obtained by selecting an appropriate temperature between the glass transition temperature and crystal melting point of the polyolefin resin as component (A).
- Uniform stretching of 70 times or more is possible in axial stretching, and uniform stretching of jXj times or more in biaxial stretching. It is also possible to uniformly uniaxially or biaxially stretch the original fabric after extracting and removing component (B) in the original fabric in the same manner as described above. In order to finally obtain a porous permeable film, it is necessary to extract and remove component (B) before or after stretching, but this step requires the use of lower alcohols that are easy to dry, considering the drying of the film after extraction. It is desirable to use a substance that can be extracted with similar substances such as methanol, ethanol, butanol, etc. as component (B). For example, this extraction process can be performed at a high speed of several minutes or less if the conditions are selected for a film of less than /lan.

Next, in order to obtain the porous permeable membrane of the present invention, it is necessary to control the temperature during the above-mentioned -axial or biaxial stretching. That is, if stretching is carried out at a temperature too close to the melting point of the polymer (component (A)), the pores formed will collapse due to the melting of component (A), making it impossible to obtain the desired permeability.

For this reason, the stretching is at most 60°C below the melting point of component (A).
It is desirable to carry out the process at a temperature between 100 and the glass transition temperature.

In addition, in order to obtain a high-strength film, the stretching speed is 50%/s.
Biaxial stretching of 3 x 3 times or more at ea or more -s ml'c
m The permeability coefficient of elementary gas is 7.0×70 (so., +7.,
crnHg) or higher can be obtained.

The porosity of the permeable film varies depending on the use and cannot be determined in general, but is usually 10-90%, preferably 30-KO.
It is at least relevant.

Furthermore, in order to apply the porous permeable film of the present invention to battery separators, medical uses, etc., it may be effective to impart water absorption properties; This can be achieved by doing so.

Various surfactants can be used, for example,
Examples of nonionic surfactants include polyols, fatty acid monoglycerides, polyoxyxy-v fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, and polyoxyethylene alkyl ethers. Examples include phosphoric acid.

As cationic surfactants, quaternary ammonium salts,
Polyoxyethylene alkylamine.

Examples include alkylamine oxides.

Examples of anionic surfactants include alkyl sulfonates and alkylbenzene sulfonates.

Alkylnaphthalene sulfonate, alkyl sulfosuccinate, alkyl sulfonic acid ester salt, polyoxyethylene alkyl sulfonic acid ester salt, polyoxyethylene alkylaryl sulfonic acid ester salt, alkyl phosphate, polyoxyethylene alkyl phosphate, etc. Can be mentioned.

11- To incorporate a surfactant into a porous film or sheet, the surfactant is mixed or dissolved in a liquid that mixes substantially uniformly with the surfactant, and the porous film or sheet is immersed in the solution. This can be done by doing this. As the liquid that mixes substantially uniformly with the surfactant, pure water, alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol are used. Mixtures of these can also be used. Furthermore, aliphatic hydrocarbons, aromatic hydrocarbons, chloroform,
Acetone, carbon tetrachloride, etc. or even mixtures thereof can also be used.

The concentration of the surfactant is preferably 0.7% by weight or more, more preferably 7% by weight or more.

If the concentration of the surfactant is less than 0.1% by weight, even if hydrophilic treatment is possible, the immersion time becomes long, which is not preferable.

A surfactant can also be impregnated after the porous film spanning sheet has been subjected to known surface treatments such as corona treatment and flame treatment.

-12= The timing of impregnating the surfactant can be either after or before stretching, but it is preferable to impregnate it after stretching.

Furthermore, when extracting the <B) component with alcohol or the like, the process can be simplified by dissolving a surfactant in the alcohol in advance.

〔Example〕

Next, examples will be shown in order to clarify the effects of the present invention. However, the present invention is not limited to these examples. The physical properties shown in the specification and examples of the present invention are as follows λ) Nitrogen gas permeability coefficient (88o, □
, crnH) Using Amicon's UP stirring cell/type C. Differential pressure/29/ctA1) Measured at temperature Ω5°C.

3) Tensile strength (Kg/rtan”) Compliant with AS'rM D-4Fl, Tensile speed: Measured at SO/min.

Further, poly-3-methylbutene-/ used in the examples was obtained by the following method.

Production Example / (a) Production of homogeneous titanium trichloride solution A four-bottle flask with a volume of fS: 500 me, which was purged with dry argon, was charged with 50'ml of purified toluene and 90 mmol of titanium tetrachloride, and further di-n-butyl ether (90 mmol).
0 mmol was added. Titanium tetrachloride and di-n-butyl ether reacted with some heat and were uniformly dissolved in toluene to obtain an orange-yellow homogeneous solution. While stirring the solution and keeping it at 25°C, 3 mmol of diethylaluminum monochloride II was added to toluene and 20
When a solution dissolved in - was gradually added, a dark orange homogeneous solution of titanium trichloride was obtained.

(b) Precipitation formation of titanium trichloride and production of catalyst (a) above
When the homogeneous solution of titanium trichloride obtained in the step was heated to 9S° C., a purple precipitate of titanium trichloride was observed during the temperature rise. ? After stirring for 60 minutes at &°C, the precipitate was separated and washed five times with 100TR1 of n-heptane to obtain a fine particulate purple titanium trichloride catalyst complex. Elemental analysis reveals that the catalyst complex has the formulas T1at, (Atcts)o, oolIC(
no4H,)20] has a composition of 0.03.

(c) Production of poly-3-methylbutene-/ Polymerization of 3-methylbutene-/ was carried out as follows using the solid titanium trichloride catalyst complex obtained in (r) above in an induction stirring autoclave with a capacity of 2 tons. Ta. 0.724 t# of the solid titanium trichloride catalyst complex obtained in the above (a) and 1/A mmol of di-iso-butylaluminum monochloride were charged into an autoclave which had been sufficiently vacuum-dried and purged with nitrogen. Then liquefy J-methylbutene-/A3011
After charging, polymerization was carried out at 70° C. for 3.S hours. Then, isobutyl alcohol 237 was charged to stop the polymerization, and excess unreacted monomer was expelled. Next, 7000 ml of n-hexane was introduced, and after stirring at 50°C for 30 minutes, the supernatant liquid was taken out and the catalyst component in the polymer was washed away. After repeating this operation S times, a portion of Irganox 1OIO (trade name) was added as an additive to the poly-3-methylbutene-/ obtained by drying white powdery poly-3, and a portion of Irgafos P-KPQ (trade name) was added as an additive. 01.2 parts of Nippon Ciba-Geigy Co., Ltd.) were added.

Example/ Poly-damethylpentene-7 (Mikata Petrochemical Industry ■TP
X D) l da S) da0 60% by weight of stearyl alcohol was uniformly mixed using a Brabender mixing machine at a temperature of 0°C, and the mixture was press-molded to a thickness of 0.
The sheet was made into a sheet of 1Iran, and the sheet was heated at 5θ to 60°C.
The mixture was treated in ethanol for 5 minutes, and 60 g of stearyl alcohol was added. The obtained sheet was white and porous. This sheet was stretched +X+ times at a temperature of 750° C. using a biaxial stretching machine. The obtained film exhibited the following properties.

Film thickness Colo μ Porosity A2% Tensile strength K, g Kg/wn” Elongation 31% Nitrogen gas permeability coefficient 3.t Poly-3 methylbutene obtained in Example Production Example/50% by weight, stearyl alcohol roz amount at 3.20°C
They were uniformly mixed using a Prabender kneader in a gold gas atmosphere at a temperature of The mixture was press-molded to create a J-shaped sheet, and then! 0-40℃
The stearyl alcohol in the sheet was extracted using ethanol for 3 minutes. The obtained sheet was whitened and porous. The porous film was biaxially stretched at a temperature of 750° C. and a uniform film could be obtained. This film exhibited the following properties.

Thickness, 22μ Porosity tr% Tensile strength 3. Kf/Scream 2 Elongation Monthly nitrogen gas permeability coefficient /, tr x 1O-4 (-!!!L K1-1)
8θC Fist CdjtYnHg Example 3 The porous permeable film obtained in Example/ was treated with a 7% ethyl alcohol solution of the nonionic surfactant polyoxyethylene sorbitan monolaurate [trade name: Tweθn-〇, Tokyo Kasei ■]. After soaking for 1 minute, the sample was air-dried. The moisture permeability and moisture absorption rate of this treated film are shown in Table 1.
On the other hand, it can be seen that both moisture permeability and moisture absorption are improved.

In addition, these measurement methods are as follows.

/) Moisture permeability (9/w*'2'1 hour): J Engineering S 201
Temperature 30℃, relative humidity according to 0g knee/974? Measured in θ%.

2) Moisture absorption rate (weight %): After drying the film at 10° C. for 3 hours, the weight increase after a certain period of time was measured under conditions of -0° C. and 700% relative humidity, and is expressed as a weight percentage.

〔Effect of the invention〕

The film of the present invention has high strength and good permeability, and has excellent heat resistance, electrical properties, chemical resistance, and solvent resistance. In other words, by combining a specific resin and a specific compounding agent, a porous and permeable film with high strength can be obtained without impairing the physical properties of the resin.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - (7 others)

Claims (1)

[Claims] (1) Made of poly-l methylpentene-/or poly-3-methylpentene, the tensile strength is J, (1) (Kf/simple 2') is 1, and the permeability coefficient of nitrogen gas is / ,oxlo
A porous permeable film with a percentage of ( ) or more. (2) The porous permeable film according to claim 1, which is obtained by making the porous permeable film hydrophilic.゛(8) (A) Poly-damethylpentene-/or poly-3-methylbutene-/resin 70~? For θ weight superiority (
B) A resin composition selected from aliphatic compounds and alicyclic compounds that is solid at room temperature, has a lower melting point than the resin used as component (A), and has an extractable component q' o -t 0% by weight. After forming a film-like body and stretching the film-like body (B)
A method for producing a porous permeable film, which comprises performing a component extraction treatment or stretching after the component (B) extraction treatment. (4) The method for manufacturing a porous permeable film according to claim 1, wherein component (B) is an aliphatic compound having 73 or more carbon atoms and a hydroxyl group, and is a woody plant.