WO2019130990A1 - Stretched porous film and method for producing same - Google Patents

Stretched porous film and method for producing same Download PDF

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Publication number
WO2019130990A1
WO2019130990A1 PCT/JP2018/044257 JP2018044257W WO2019130990A1 WO 2019130990 A1 WO2019130990 A1 WO 2019130990A1 JP 2018044257 W JP2018044257 W JP 2018044257W WO 2019130990 A1 WO2019130990 A1 WO 2019130990A1
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Prior art keywords
mass
porous film
parts
less
stretched porous
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PCT/JP2018/044257
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French (fr)
Japanese (ja)
Inventor
邦男 鎌田
田中　伸幸
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株式会社トクヤマ
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Priority to JP2019562894A priority Critical patent/JP7112430B2/en
Publication of WO2019130990A1 publication Critical patent/WO2019130990A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
    • B29C67/20—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 for porous or cellular articles, e.g. of foam plastics, coarse-pored
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof

Definitions

  • the present invention relates to a stretched porous film and a method for producing the same.
  • a porous film in which a water-repellent resin such as a polyolefin resin is formed into a film and fine pores are formed is used. Such a porous film allows air to pass but does not allow liquid to pass.
  • Patent Document 1 discloses a breathable film obtained by melt-molding a resin composition containing a polyethylene-based resin, liquid paraffin and an inorganic filler.
  • One aspect of the present invention is made in view of the above-mentioned problems, and the object thereof is to realize a stretched porous film having both breathability, water resistance and flexibility suitable for personal care products such as diapers. It is.
  • the present invention includes the following configurations.
  • This is a stretched porous film characterized by having the moisture permeability of 1400 g / m 2 ⁇ 24 h or more measured under the conditions of 40 ° C. and 60% relative humidity according to ASTM E96.
  • Density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, and the liquid paraffin 20 parts by mass or less
  • the melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210, including a porosifying step of porosifying, at 2.0 g / 10 min. It is the above, The manufacturing method of the extending
  • Patent Document 1 is considered to be poor in flexibility because it uses a polyethylene resin having a low melt index.
  • the stretched porous film according to one embodiment of the present invention solves the problems of the prior art described above, and has both air permeability, moisture permeability and flexibility. The details will be described below.
  • Stretched porous film according to an embodiment of the present invention has a density of 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin-based resin 100 parts by weight, 5.
  • the melt mass flow rate of the resin composition is composed of a resin composition containing 0 parts by mass or more and 20 parts by mass or less of liquid paraffin and an inorganic filler, and measured at 190 ° C. according to JIS K 7210. 2.0 g / 10 min. This is the above, and the moisture permeability measured under the conditions of 40 ° C.
  • the stretched porous film may be made of a resin composition containing a polyolefin resin, liquid paraffin and an inorganic filler, and, for example, a sheet of another material or the like may be laminated in addition to the resin composition. It may also be
  • the polyolefin resin has a density of 0.900 g / cm 3 or more and 0.940 g / cm 3 or less, more preferably 0.905 g / cm 3 or more and 0.935 g / cm 3 or less. If the density is in the above-mentioned range, a stretched porous film having desired flexibility can be obtained by combining with liquid paraffin described later. Also, the density and the melting point are correlated to some extent. If the density is in the above range, the heat setting temperature is somewhat different from the melting point, so that it is possible to prevent the polyolefin resin from melting and blocking the pores of the stretched porous film simultaneously with the heat setting. Therefore, the decrease in air permeability can be prevented.
  • linear low density polyethylene LLDPE
  • LDPE branched low density polyethylene
  • the use of a plurality of types of polyolefin resins is preferable because the melt mass flow rate can be easily adjusted.
  • linear low density polyethylene and branched low density polyethylene may be combined. From the viewpoint of improving heat resistance, a polyolefin resin having a density of 0.930 g / cm 3 or more and 0.970 g / cm 3 or less may be contained with respect to 100 parts by mass of the polyolefin resin.
  • the density of the entire polyolefin resin used may be 0.940 g / cm 3 or less.
  • the density of the polyolefin resin is more preferable to use all 0.900 g / cm 3 or more and 0.940 g / cm 3 or less.
  • Liquid paraffin is a mixture of hydrocarbons having a wide range of about 15 to 35 carbon atoms that is liquid at normal temperature and obtained from crude oil, and has a density of 0.790 g / cm 3 or more and 0.920 g / cm 3 or less I say something.
  • Liquid paraffin is added to improve flexibility.
  • the content ratio of the liquid paraffin is preferably 5.0 parts by mass or more and 20 parts by mass or less, and more preferably 7.0 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the polyolefin resin preferable. If the content ratio of liquid paraffin is 5.0 parts by mass or more, flexibility can be further imparted to the stretched porous film. Moreover, if the content rate of liquid paraffin is 20 mass parts or less, the intensity
  • Inorganic filler is added to make the film porous.
  • Known inorganic fillers can be used without limitation.
  • inorganic salts such as calcium carbonate, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, and aluminum hydroxide
  • inorganic oxides such as zinc oxide, magnesium oxide and silica And silicates such as mica, vermiculite and talc
  • organic metal salts such as calcium carbonate is preferable from the viewpoint of cost performance and dissociativeness with a polyolefin resin.
  • the blending ratio of the inorganic filler is preferably 80 parts by mass or more and 200 parts by mass or less, and 85 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the polyolefin resin and liquid paraffin in total. It is more preferable that If the blending ratio of the inorganic filler is 80 parts by mass or more, it is possible to increase the frequency of void generation per unit area, which is caused by the separation of the polyolefin resin and the inorganic filler. Therefore, the adjacent voids are likely to communicate with each other, and the air permeability becomes good. When the proportion of the inorganic filler is 200 parts by mass or less, the elongation at the time of film stretching is good, and the stretching is easy.
  • the resin composition may further contain an additive used in a normal resin composition.
  • additives include antioxidants, heat stabilizers, light stabilizers, ultraviolet light absorbers, neutralizing agents, lubricants, antifogging agents, antiblocking agents, antistatic agents, slip agents, coloring agents, plasticizers, etc. It can be mentioned.
  • a small amount of a resin component other than that constituting the polyolefin resin and the liquid paraffin may be blended within a range not impairing the effects of the present invention.
  • the stretched porous film and the resin composition according to an embodiment of the present invention may not contain a thermoplastic elastomer.
  • the moisture permeability of the stretched porous film is preferably 1400 g / m 2 ⁇ 24 h or more, and more preferably 1600 g / m 2 ⁇ 24 h or more.
  • the upper limit of moisture permeability, mechanical properties, from the viewpoints of water resistance and liquid leakage resistance is preferably not more than 10000g / m 2 ⁇ 24h, more preferably at most 4000g / m 2 ⁇ 24h.
  • the diaper using the stretched porous film has a lower possibility of liquid leakage when worn.
  • the moisture permeability of the film shown by patent document 1 is over 4000 g / m 2 ⁇ 24 h in all cases, it is considered that there is a possibility that liquid leakage may occur at the time of wearing when used for a diaper or the like.
  • the moisture permeability is measured according to ASTM E96 under conditions of a pure water method at 40 ° C., 60% relative humidity, and a measuring time of 24 hours.
  • the moisture permeability is the average value of 10 samples of 10 cm ⁇ 10 cm collected from the stretched porous film.
  • the 5% tensile strength of the stretched porous film is preferably 0.3 N / 25 mm or more and less than 2.5 N / 25 mm, and more preferably 0.5 N / 25 mm or more and 2.3 N / 25 mm or less.
  • the smaller the 5% tensile strength the more flexible it is. If the 5% tensile strength is less than 2.5 N / 25 mm, more flexibility can be imparted. If the 5% tensile strength is 0.3 N / 25 mm or more, it is possible to suppress the film elongation to the line tension applied in the machine direction at the time of secondary processing.
  • the 5% tensile strength of the sample at a chuck distance of 50 mm and a tensile speed of 200 mm / min is measured as the strength in the machine direction when the sample is stretched 5%. That is, 5% tensile strength is measured as stress in the machine direction when the distance between chucks is expanded by 2.5 mm. Further, in the present specification, 5% tensile strength is a value measured for a sample having a width of 25 mm and a length in the machine direction of 150 mm collected from a stretched porous film.
  • the melt mass flow rate of the resin composition is 2.0 g / 10 min. It is preferable that it is more than 2.0 g / 10 min. Above, 6.0 g / 10 min. Or less, more preferably 2.0 g / 10 min. Above, 5.0 g / 10 min. It is more preferable that it is the following. If the melt mass flow rate is in the above range, more stable film formation can be performed. The melt mass flow rate is 2.0 g / 10 min. If it is the above, the resin pressure of the film forming extruder can be suppressed, and an adverse effect on film forming can be prevented. Moreover, the melt mass flow rate is 6.0 g / 10 min.
  • melt mass flow rate and 5% tensile strength tend to be correlated. Decreasing the melt mass flow rate increases the 5% tensile strength and therefore tends to result in a stretched porous film with poor flexibility.
  • the melt mass flow rate of the resin composition is measured by Method A at 190 ° C. according to JIS K 7210.
  • the air permeability of the stretched porous film is preferably 300 seconds / 100 mL or more and 2000 seconds / 100 mL or less, more preferably 400 seconds / 100 mL or more and 1600 seconds / 100 mL or less, and 400 seconds / 100 mL or more. More preferably, it is 1100 seconds / 100 mL or less.
  • the lower the permeability the easier it is for gas to pass.
  • the air permeability is measured by the Oken type tester according to JIS P 8117.
  • the heat shrinkage rate in the machine direction of the stretched porous film is preferably 5.0% or less, and more preferably 3.5% or less. If the 5% tensile strength is high and the heat shrinkage rate in the machine direction is 5.0% or less, the film elongation to the line tension applied in the machine direction at the time of secondary processing can be further suppressed.
  • the heat shrinkage rate in the machine direction is preferably as close to 0% as possible, but is practically 0.5% or more.
  • the heat shrinkage rate in the machine direction is measured by the following method. A sample of 15 cm ⁇ 15 cm is taken from the stretched porous film. Make a mark on this sample so that there is 10 cm between marks in the machine direction. The sample is left at 50 ° C. for 24 hours, then cooled to room temperature and the length between marks is measured.
  • the heat shrinkage rate in the machine direction can be obtained from the following formula I.
  • the basis weight is preferably 10 g / m 2 or more and 35 g / m 2 or less, more preferably 11 g / m 2 or more and 32 g / m 2 or less, and 12 g / m 2 or more and 30 g / m 2 or less It is further preferred that When the weight per unit area is in the above range, a stretched porous film excellent in air permeability, moisture permeability and mechanical strength can be obtained. When the basis weight is 10 g / m 2 or more, the mechanical strength of the film can be increased. Moreover, if the fabric weight is 35 g / m 2 or less, sufficient moisture permeability can be obtained.
  • Method for producing a stretched porous film according to an embodiment of the present invention has a density of 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin-based resin 100 parts by weight
  • a stretched porous film having desired flexibility in addition to water resistance can be obtained.
  • a resin composition having a melt mass flow rate in a specific range improves the flowability of the resin composition, and a flexible stretched porous film is obtained.
  • a stretched porous film having desired air permeability can be obtained. Therefore, a stretched porous film having both air permeability, water resistance and flexibility can be realized.
  • Mixing step has a density of 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, below 20 parts by weight
  • a liquid paraffin and an inorganic filler are mixed to obtain a resin composition.
  • a polyolefin resin, liquid paraffin, an inorganic filler, and, if necessary, additives to be blended are mixed.
  • the mixing method is not particularly limited, and known methods can be adopted. For example, it is preferable to mix for about 5 minutes to 1 hour using a mixer such as a Henschel mixer, a super mixer, or a tumbler mixer.
  • the obtained mixture can be generally kneaded and pelletized by a method such as strand cut, hot cut or underwater cut using a kneader such as a high kneader type twin screw extruder or a tandem type kneader. It is preferable because mixing and kneading in advance and pelletization can promote uniform dispersion of the resin composition. Further, depending on the composition of the resin composition, it can be directly put into a kneader without mixing and pelletized.
  • the molding step is a step of molding the resin composition into a film.
  • the pellets obtained as described above are preferably formed into a film by a circular die or a T-die attached to the tip of an extruder.
  • the cooling method in the case of using the T-die method is not particularly limited, and a known method such as a nipple roll method, an air knife method, or an air chamber method can be adopted.
  • the film may be formed by directly charging the resin composition into an extruder without mixing and kneading.
  • the porosifying step is a step in which the film obtained by the forming step is rendered porous by drawing at least in the machine direction.
  • the interface between the resin component (the polyolefin resin and the liquid paraffin) and the inorganic filler is peeled off.
  • a minute void is formed at the peeled interface, and the void forms a communicating hole penetrating in the thickness direction of the film, whereby a stretched porous film is formed.
  • Stretching can be performed by a known method such as roll stretching or tenter stretching. The stretching may be uniaxial stretching or biaxial stretching.
  • the draw ratio of the machine direction in the said porosification process is shown by the following formula II: 1.4 ⁇ Y ⁇ 0.075X + 1.8 (Formula II) (In the formula, X represents a blending ratio (parts by mass) of liquid paraffin to 100 parts by mass of a polyolefin resin, and Y represents a stretching ratio (fold)).
  • the obtained film is sufficiently stretched while having flexibility, so that the thickness unevenness is unlikely to occur, and the tear strength is good and sufficient. Holes of number and size are formed. Therefore, with such a stretching ratio, a stretched porous film having both air permeability, moisture permeability and flexibility can be obtained more easily.
  • the stretching may be single-stage stretching or multi-stage stretching.
  • stretching temperature is a temperature range above normal temperature and less than the softening point of a resin composition. If the stretching temperature is equal to or higher than normal temperature, stretching unevenness is unlikely to occur, so the thickness tends to be uniform. In addition, when the stretching temperature is less than the softening point, it is possible to prevent the stretched porous film from melting. Therefore, it is possible to prevent the pores of the stretched porous film from being crushed and the air permeability and the moisture permeability being lowered.
  • the stretching temperature can be appropriately adjusted by the combination of the physical properties of the resin composition used and the stretching ratio.
  • the manufacturing method may include a heat setting step.
  • the heat setting step is a step of heat setting the stretched porous film after stretching in order to suppress heat shrinkage in the stretching direction.
  • the heat setting is a heat treatment performed in an environment in which the dimensions are not changed while maintaining a stretched state of the stretched film. As a result, it is possible to suppress elastic recovery during storage, contraction due to heat, squeezing, etc. by heat setting.
  • a heat setting method in the case of adopting a roll drawing method as a drawing method a method of heating a film after drawing with a heated roll (annealing roll) can be mentioned.
  • a heat setting method in the case where the tenter stretching method is adopted as the stretching method a method of heating the film after stretching in the vicinity of the tenter outlet may be mentioned.
  • the heat setting temperature is preferably 70 ° C. or more and 95 ° C. or less, and more preferably 80 ° C. or more and 95 ° C. or less. If the heat setting temperature is 70 ° C. or more, heat shrinkage can be suppressed by sufficient heat setting. In addition, when the heat setting temperature is 95 ° C. or less, the pores of the stretched porous film can be further prevented from being crushed by heat.
  • the heat setting time is preferably 0.2 seconds or more, more preferably 0.5 seconds or more, and still more preferably 1.0 seconds or more. If the heat setting time is 0.2 seconds or more, the heat shrinkage can be suppressed by sufficient heat setting.
  • the heat setting time is preferably 20 seconds or less, more preferably 15 seconds or less. Although it depends on the combination with the heat setting temperature, it can not be said in general, but if the heat setting time is 20 seconds or less, it is possible to prevent the pores from being crushed by melting of the stretched porous film. Therefore, the air permeability and the moisture permeability can be prevented from being lowered.
  • the heat setting time is the time for which the stretched porous film is kept at the heat setting temperature.
  • the roll stretching method refers to the time during which the film is in contact with the annealing roll.
  • the number of annealing rolls is not particularly limited, but in the case of two or more, the heat setting time is the sum of the time when the stretched porous film is in contact with each annealing roll.
  • the time of heat setting indicates the time of heating and maintaining at the heat setting temperature at the tenter outlet. When heat setting is divided into multiple times and heated, it is the sum of each heating time.
  • melt mass flow rate The melt mass flow rate of the resin composition was measured according to JIS K 7210, at 190 ° C. as the measurement temperature, and measured by method A. In the following, melt mass flow rate is also referred to as MI (melt index).
  • 5% tensile strength According to JIS K 7127, a sample having a width of 25 mm and a machine direction length of 150 mm was collected from the stretched porous film. This sample was subjected to a chuck distance of 50 mm, a pulling speed of 200 mm / min. The tensile strength in the machine direction was measured as 5% tensile strength when the sample was stretched 5%. That is, the stress in the machine direction was measured when the distance between chucks was increased by 2.5 mm.
  • A Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2047, density: 0.917 g / cm 3 , MI: 2.3 g / 10 min. ]
  • B Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2035 G, density: 0.919 g / cm 3 , MI: 6.0 g / 10 min. ]
  • C Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2036P, density: 0.935 g / cm 3 , MI: 2.5 g / 10 min.
  • D Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2045 G, density: 0.920 g / cm 3 , MI: 1.0 g / 10 min. ]
  • E Branched low density polyethylene [Mitsui-Dupont Polychemicals Co., Ltd., trade name: Mirason 16P, density: 0.917 g / cm 3 , MI: 3.7 g / 10 min. ]
  • F Ultra-low density polyethylene [Dow Chemical Co., Ltd., trade name: Atein 4607 GC, density 0.904 g / cm 3 , MI: 4.0 g / 10 min.
  • G High density polyethylene [manufactured by Tosoh Corp., trade name: Nipolon Hard 4200, density: 0.961 g / cm 3 , MI: 2.3 g / 10 min. ]
  • H liquid paraffin [manufactured by Wako Pure Chemical Industries, Ltd., trade name: liquid paraffin, density: 0.860 to 0.890 g / cm 3 ]
  • I liquid paraffin [manufactured by Wako Pure Chemical Industries, Ltd., trade name: liquid paraffin, density: 0.825 to 0.850 g / cm 3 ]
  • J Liquid paraffin [manufactured by Wako Pure Chemical Industries, Ltd., trade name: liquid paraffin, density: 0.800 to 0.835 g / cm 3 ]
  • K Paraffin (manufactured by Wako Pure Chemical Industries, Ltd., trade name: Paraffin, melting point: 42 to 44 ° C., density: 0.900 g / cm 3 )
  • L Hydrogenated poly
  • Example 1 It was set as the resin composition which mixed the polyolefin resin of Table 1, hydrocarbon, an inorganic filler, and an additive. It was granulated and then film formation was performed.
  • Granulation preparation of pellets was performed as follows.
  • the resin composition was extruded into strands at a cylinder temperature of 160 ° C. using a vented ⁇ 30 mm twin-screw extruder, and cooled in a water bath. Thereafter, the extruded resin composition was cut to about 5 mm and dried to prepare pellets.
  • a film was formed from the pellets using a ⁇ 400 mm T film forming machine.
  • lip clearance 1.5 mm
  • die temperature 200 ° C.
  • air gap 105 mm
  • take-up speed 10 m / min.
  • Cast roll temperature 20 ° C.
  • the obtained film was further uniaxially stretched (stretching ratio: 1.8 times) only in the machine direction by a roll stretcher set at 40 ° C., and then inline annealing was performed by a heat set roll set at 90 ° C. (heat setting time 4) Seconds).
  • the heat shrinkage rate in the machine direction at the time of heat setting was 8%.
  • Example 1 is used except that the blending ratio of each component or the stretching condition (stretching ratio or heat setting temperature) is changed as described in Table 1 and Table 2. A film was formed as well.
  • polyolefin resin compounding ratio (mass%)
  • “Hydrocarbon: blending ratio (parts by mass)” represents the blending ratio of hydrocarbons to 100 parts by mass of the polyolefin resin.
  • the blending ratio of calcium carbonate and additives is described as a blending ratio with respect to a total of 100 parts by mass of the polyolefin resin and the hydrocarbon.
  • the stretching condition * 1 represents a stretching ratio of 1.8 times and a heat setting temperature of 90 ° C.
  • the stretching condition * 2 represents a stretching ratio of 3.2 times and a heat setting temperature of 90 ° C.
  • the stretching condition * 3 indicates a stretching ratio of 2.5 times and a heat setting temperature of 90 ° C.
  • the stretching condition * 4 indicates that the stretching condition is 1.3 times and the heat setting temperature is 90 ° C.
  • the stretched porous films of Examples 1 to 13 all exhibited good moisture permeability of at least 1400 g / m 2 ⁇ 24 h, and also had good texture. Also, the stretched porous films of Examples 1-8 and 10-12 maintained low values for 5% tensile strength and thermal shrinkage. Furthermore, in the stretched porous films of Examples 1 to 8 and 10 to 12, any stretching ratio satisfies Formula II.
  • Example 4 polyolefin resins having different densities were used.
  • polyethylene having a density of 0.961 g / cm 3 was used.
  • Example 4 to which high density polyethylene is added the moisture permeability is higher and the air permeability is lower than Example 3.
  • the result of 5% elongation strength was high in Example 4, it was better than the comparative example.
  • Examples 2, 9 and 12 changed the draw ratio of the stretched porous film of the same composition. From these, it can be seen that the moisture permeability is increased and the air permeability and the thermal contraction rate are decreased by increasing the draw ratio.
  • Comparative Examples 2 to 5 hydrocarbons other than liquid paraffin were used as the hydrocarbons.
  • Comparative Example 2 in which paraffin was used as a hydrocarbon
  • Comparative Example 5 in which hydrogenated polybutene was used as a hydrocarbon
  • a stretched porous film having high 5% elongation strength and poor flexibility was obtained.
  • Comparative Example 3 in which hydrogenated polybutadiene was used as the hydrocarbon
  • Comparative Example 4 in which polybutene was used as the hydrocarbon, the moisture permeability was low in any case, and a stretchable porous film which is easily steamed was obtained.
  • Comparative Example 6 75% by mass of polyethylene having a density of 0.961 g / cm 3 was used with respect to 100 parts by mass of the polyolefin resin. As a result, a less flexible stretched porous film with low air permeability, high moisture permeability and 5% tensile strength was obtained.
  • Comparative Example 7 a polyolefin resin having a low melt mass flow rate was used. As a result, the obtained stretched porous film has a low moisture permeability, and a stretched porous film which is easy to steam is obtained.
  • Comparative Example 8 was a stretched porous film inferior in air permeability because of low moisture permeability.
  • the resin composition is composed of a liquid paraffin and an inorganic filler, and the melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min.
  • This is a stretched porous film characterized by having the moisture permeability of 1400 g / m 2 ⁇ 24 h or more measured under the conditions of 40 ° C. and 60% relative humidity according to ASTM E96.
  • the distance between chucks is 50 mm
  • the tensile speed is 200 mm / min.
  • Tensile strength in the machine direction when the distance between chucks is extended by 5% in the machine direction, and the tensile strength in the machine direction is 0.3 N / 25 mm or more and 2.5 N / 25 mm or less. the film.
  • the air permeability measured by the Oken type tester according to JIS P 8117 is 300 seconds / 100 mL or more and 2000 seconds / 100 mL or less, according to [1] or [2]. Stretched porous film.
  • the melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min. It is the above, The manufacturing method of the extending
  • the present invention can be suitably used, for example, in personal care products such as diapers.

Abstract

The present invention enables the achievement of a stretched porous film which has air permeability, water resistance and flexibility at the same time. A stretched porous film according to one embodiment of the present invention contains a resin composition that contains a specific polyolefin resin and a liquid paraffin at a specific mass ratio; and the water vapor permeability of this stretched porous film is 1,400 g/m2·24 h or more.

Description

延伸多孔性フィルムおよびその製造方法Stretched porous film and method for producing the same
　本発明は延伸多孔性フィルムおよびその製造方法に関する。 The present invention relates to a stretched porous film and a method for producing the same.
　従来、おむつ等の個人ケアー製品は、蒸れ等を防止するため空気および蒸気等を通過させ、液体を通過させないことが求められている。そのため、おむつ等の個人ケアー製品には通気性および耐水性が要求される。その要求に答えるため、ポリオレフィン系樹脂のような撥水性を有する樹脂をフィルム状に成形し、微細な孔を形成させた多孔性フィルムが利用されている。このような多孔性フィルムは空気等を通過させるが、液体を通過させない構造をしている。 In the past, personal care products such as diapers have been required to pass air, steam, etc. and not liquid in order to prevent stuffiness and the like. Therefore, breathability and water resistance are required for personal care products such as diapers. In order to meet the demand, a porous film in which a water-repellent resin such as a polyolefin resin is formed into a film and fine pores are formed is used. Such a porous film allows air to pass but does not allow liquid to pass.
　特許文献１には、ポリエチレン系樹脂と、流動パラフィンと、無機充填剤とを含有する樹脂組成物を溶融成形して得られる通気性フィルムが開示されている。 Patent Document 1 discloses a breathable film obtained by melt-molding a resin composition containing a polyethylene-based resin, liquid paraffin and an inorganic filler.
日本国公開特許公報「特開昭６２－２５００３８号」Japanese Patent Application Publication "Japanese Patent Application Laid-Open No. 62-250038"
　しかしながら、上述の通気性フィルムは、柔軟性の面で改善の余地があった。 However, the above-mentioned breathable film has room for improvement in terms of flexibility.
　本発明の一態様は、前記の問題点に鑑みてなされたものであり、その目的はおむつ等の個人ケアー製品へ好適な通気性、耐水性および柔軟性を兼ね備えた延伸多孔性フィルムを実現することである。 One aspect of the present invention is made in view of the above-mentioned problems, and the object thereof is to realize a stretched porous film having both breathability, water resistance and flexibility suitable for personal care products such as diapers. It is.
　上述の課題を解決するために、本発明者が鋭意研究を行った結果、特定のメルトマスフローレイトを有するポリオレフィン系樹脂を使用すること、該ポリオレフィン系樹脂に対して流動パラフィンを特定の質量比にて含む樹脂組成物を用いること、そして透湿度を特定の範囲に調整すること、これらの組み合わせにより、通気性、耐水性および柔軟性を兼ね備えた延伸多孔性フィルムを実現できることを見出した。即ち、本発明は以下の構成を含む。 As a result of intensive studies conducted by the present inventor in order to solve the above-mentioned problems, it is possible to use a polyolefin resin having a specific melt mass flow rate, to make a specific mass ratio of liquid paraffin to the polyolefin resin. It has been found that a stretched porous film having both air permeability, water resistance, and flexibility can be realized by using a resin composition containing N, and adjusting the moisture permeability to a specific range, and a combination thereof. That is, the present invention includes the following configurations.
　密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を含有する樹脂組成物より構成され、ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であり、ＡＳＴＭ　Ｅ９６に準じて４０℃、相対湿度６０％の条件で測定される透湿度が１４００ｇ／ｍ２・２４ｈ以上であることを特徴とする延伸多孔性フィルム。 Density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, and the liquid paraffin 20 parts by mass or less And an inorganic filler, and the melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min. This is a stretched porous film characterized by having the moisture permeability of 1400 g / m 2 · 24 h or more measured under the conditions of 40 ° C. and 60% relative humidity according to ASTM E96.
　密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を混合して樹脂組成物を得る混合工程と、前記樹脂組成物をフィルム状に成形する成形工程と、前記成形工程によって得られたフィルムを少なくとも機械方向に延伸することで多孔化させる多孔化工程と、を含み、　ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であることを特徴とする延伸多孔性フィルムの製造方法。 Density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, and the liquid paraffin 20 parts by mass or less Mixing the inorganic filler to obtain a resin composition, forming the resin composition into a film, and stretching the film obtained by the forming at least in the machine direction. The melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210, including a porosifying step of porosifying, at 2.0 g / 10 min. It is the above, The manufacturing method of the extending | stretching porous film characterized by the above-mentioned.
　本発明の一態様によれば、通気性、透湿性および柔軟性を兼ね備えた延伸多孔性フィルムが得られるという効果を奏する。 According to one aspect of the present invention, it is possible to obtain a stretched porous film having both air permeability, moisture permeability and flexibility.
　本発明の一実施形態について以下に説明するが、本発明はこれに限定されるものではない。 Although one embodiment of the present invention is described below, the present invention is not limited to this.
　本発明者が鋭意検討したところ、上述した従来技術には以下の問題点があることがわかった。例えば、特許文献１に示されたフィルムは、メルトインデックスの低いポリエチレン樹脂を用いているため柔軟性に乏しいと考えられる。 As a result of intensive studies by the present inventor, it has been found that the above-described prior art has the following problems. For example, the film shown in Patent Document 1 is considered to be poor in flexibility because it uses a polyethylene resin having a low melt index.
　そこで、本発明の一実施形態に係る延伸多孔質フィルムは、上述した従来技術の問題点を解決するものであり、通気性、透湿性および柔軟性を兼ね備える。以下、詳説する。 Therefore, the stretched porous film according to one embodiment of the present invention solves the problems of the prior art described above, and has both air permeability, moisture permeability and flexibility. The details will be described below.
　〔１．延伸多孔性フィルム〕
　本発明の一実施形態に係る延伸多孔性フィルムは、密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下の流動パラフィンと、無機充填剤と、を含有する樹脂組成物より構成され、ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であり、ＡＳＴＭ　Ｅ９６に準じて４０℃、相対湿度６０％の条件で測定される透湿度が１４００ｇ／ｍ２・２４ｈ以上である。このように特定の物性を有するポリオレフィン系樹脂に対して、流動パラフィンを特定の質量比にて組み合わせることにより、耐水性に加えて所望の柔軟性が得られる。また、透湿度を特定の範囲とすることにより、所望の通気性が得られる。それゆえ、通気性、耐水性および柔軟性を兼ね備えた延伸多孔性フィルムを実現できる。 [1. Stretched porous film]
Stretched porous film according to an embodiment of the present invention has a density of 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin-based resin 100 parts by weight, 5. The melt mass flow rate of the resin composition is composed of a resin composition containing 0 parts by mass or more and 20 parts by mass or less of liquid paraffin and an inorganic filler, and measured at 190 ° C. according to JIS K 7210. 2.0 g / 10 min. This is the above, and the moisture permeability measured under the conditions of 40 ° C. and 60% relative humidity in accordance with ASTM E96 is 1400 g / m 2 · 24 h or more. Thus, by combining liquid paraffin with a specific weight ratio to a polyolefin resin having specific physical properties, desired flexibility can be obtained in addition to water resistance. Further, by setting the moisture permeability in a specific range, desired air permeability can be obtained. Therefore, a stretched porous film having both air permeability, water resistance and flexibility can be realized.
　なお、延伸多孔性フィルムは、ポリオレフィン系樹脂と流動パラフィンと無機充填剤とを含む樹脂組成物からなるものであってもよいし、例えば、樹脂組成物の他に別の材質のシート等が積層されているものであってもよい。 The stretched porous film may be made of a resin composition containing a polyolefin resin, liquid paraffin and an inorganic filler, and, for example, a sheet of another material or the like may be laminated in addition to the resin composition. It may also be
　＜１－１．ポリオレフィン系樹脂＞
　前記ポリオレフィン系樹脂は、密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であり、より好ましくは０．９０５ｇ／ｃｍ３以上、０．９３５ｇ／ｃｍ３以下である。密度が前記範囲であれば、後述する流動パラフィンと組み合わせることにより所望の柔軟性を有する延伸多孔性フィルムが得られる。また、密度と融点とはある程度相関する。密度が前記範囲であれば、熱固定温度が融点とある程度離れているため、熱固定と同時にポリオレフィン系樹脂が融解して延伸多孔性フィルムの孔が塞がることを防ぐことができる。従って、通気性の低下を防ぐことができる。 <1-1. Polyolefin resin>
The polyolefin resin has a density of 0.900 g / cm 3 or more and 0.940 g / cm 3 or less, more preferably 0.905 g / cm 3 or more and 0.935 g / cm 3 or less. If the density is in the above-mentioned range, a stretched porous film having desired flexibility can be obtained by combining with liquid paraffin described later. Also, the density and the melting point are correlated to some extent. If the density is in the above range, the heat setting temperature is somewhat different from the melting point, so that it is possible to prevent the polyolefin resin from melting and blocking the pores of the stretched porous film simultaneously with the heat setting. Therefore, the decrease in air permeability can be prevented.
　前記ポリオレフィン系樹脂としては、線形低密度ポリエチレン（ＬＬＤＰＥ）および分岐状低密度ポリエチレン（ＬＤＰＥ）が挙げられる。なお、複数種類のポリオレフィン系樹脂を用いると、メルトマスフローレイトを容易に調整することができるため好ましい。ポリオレフィン系樹脂として、線形低密度ポリエチレンと分岐状低密度ポリエチレンとを組み合わせてもよい。なお、耐熱性を向上させる観点から、ポリオレフィン系樹脂１００質量部に対し、密度が０．９３０ｇ／ｃｍ３以上、０．９７０ｇ／ｃｍ３以下のポリオレフィン系樹脂を含んでもよい。その場合、用いたポリオレフィン系樹脂全体の密度（複数種類のポリオレフィン系樹脂の混合物の密度）が０．９４０ｇ／ｃｍ３以下であればよい。より好ましくは用いるポリオレフィン系樹脂の密度がすべて０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下である。 As said polyolefin resin, linear low density polyethylene (LLDPE) and branched low density polyethylene (LDPE) are mentioned. The use of a plurality of types of polyolefin resins is preferable because the melt mass flow rate can be easily adjusted. As the polyolefin resin, linear low density polyethylene and branched low density polyethylene may be combined. From the viewpoint of improving heat resistance, a polyolefin resin having a density of 0.930 g / cm 3 or more and 0.970 g / cm 3 or less may be contained with respect to 100 parts by mass of the polyolefin resin. In that case, the density of the entire polyolefin resin used (the density of the mixture of plural types of polyolefin resins) may be 0.940 g / cm 3 or less. The density of the polyolefin resin is more preferable to use all 0.900 g / cm 3 or more and 0.940 g / cm 3 or less.
　＜１－２．流動パラフィン＞
　流動パラフィンとは、原油から得られる、常温で液状の炭素数１５～３５程度の広い範囲を持つ炭化水素の混合物であり、密度が０．７９０ｇ／ｃｍ３以上、０．９２０ｇ／ｃｍ３以下のものをいう。 <1-2. Liquid paraffin>
Liquid paraffin is a mixture of hydrocarbons having a wide range of about 15 to 35 carbon atoms that is liquid at normal temperature and obtained from crude oil, and has a density of 0.790 g / cm 3 or more and 0.920 g / cm 3 or less I say something.
　流動パラフィンは柔軟性を向上させる目的で加えられる。流動パラフィンの含有割合は、ポリオレフィン系樹脂１００質量部に対して、５．０質量部以上、２０質量部以下であることが好ましく、７．０質量部以上、３０質量部以下であることがより好ましい。流動パラフィンの含有割合が５．０質量部以上であれば、延伸多孔性フィルムに、より柔軟性を付与することができる。また、流動パラフィンの含有割合が２０質量部以下であれば、延伸多孔性フィルムの強度を高めることができる。またドローレゾナンス現象の発生を抑制することができるため、生産性を向上することができる。 Liquid paraffin is added to improve flexibility. The content ratio of the liquid paraffin is preferably 5.0 parts by mass or more and 20 parts by mass or less, and more preferably 7.0 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the polyolefin resin preferable. If the content ratio of liquid paraffin is 5.0 parts by mass or more, flexibility can be further imparted to the stretched porous film. Moreover, if the content rate of liquid paraffin is 20 mass parts or less, the intensity | strength of an extending | stretching porous film can be raised. In addition, since the occurrence of the draw resonance phenomenon can be suppressed, the productivity can be improved.
　＜１－３．無機充填剤＞
　無機充填剤は、フィルムを多孔化させるために加えられている。無機充填剤は公知のものが際限なく使用でき、例えば炭酸カルシウム、硫酸バリウム、硫酸カルシウム、炭酸バリウム、水酸化マグネシウムおよび水酸化アルミニウム等の無機塩類、酸化亜鉛、酸化マグネシウムおよびシリカ等の無機酸化物、マイカ、バーミキュライトおよびタルク等のケイ酸塩類、並びに有機金属塩が挙げられる。前記無機充填剤のうち、炭酸カルシウムが、コストパフォーマンスおよびポリオレフィン系樹脂との解離性の観点から好ましい。 <1-3. Inorganic filler>
Inorganic fillers are added to make the film porous. Known inorganic fillers can be used without limitation. For example, inorganic salts such as calcium carbonate, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, and aluminum hydroxide, inorganic oxides such as zinc oxide, magnesium oxide and silica And silicates such as mica, vermiculite and talc, and organic metal salts. Among the above-mentioned inorganic fillers, calcium carbonate is preferable from the viewpoint of cost performance and dissociativeness with a polyolefin resin.
　樹脂組成物において、無機充填剤の配合割合は、ポリオレフィン系樹脂および流動パラフィン合計１００質量部に対し、８０質量部以上、２００質量部以下であることが好ましく、８５質量部以上、１５０質量部以下であることがより好ましい。無機充填剤の配合割合が８０質量部以上であれば、ポリオレフィン系樹脂と無機充填剤とが乖離してできる、単位面積あたりのボイド発生頻度を高めることができる。よって、近接したボイド同士が連通しやすくなり、通気性が良好となる。無機充填剤の配合割合が２００質量部以下であれば、フィルム延伸時の伸びが良好であり、延伸が容易である。 In the resin composition, the blending ratio of the inorganic filler is preferably 80 parts by mass or more and 200 parts by mass or less, and 85 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the polyolefin resin and liquid paraffin in total. It is more preferable that If the blending ratio of the inorganic filler is 80 parts by mass or more, it is possible to increase the frequency of void generation per unit area, which is caused by the separation of the polyolefin resin and the inorganic filler. Therefore, the adjacent voids are likely to communicate with each other, and the air permeability becomes good. When the proportion of the inorganic filler is 200 parts by mass or less, the elongation at the time of film stretching is good, and the stretching is easy.
　＜１－４．その他の成分＞
　樹脂組成物にはさらに、通常の樹脂組成物に用いられる添加物が含まれていてもよい。かかる添加物としては、酸化防止剤、熱安定剤、光安定剤、紫外線吸収剤、中和剤、滑剤、防曇剤、アンチブロッキング剤、帯電防止剤、スリップ剤、着色剤、可塑剤等が挙げられる。なお、樹脂組成物には、本発明の効果を損なわない範囲で、ポリオレフィン系樹脂および流動パラフィンを構成する以外の樹脂成分が少量配合されていてもよい。具体的には、ポリオレフィン系樹脂および流動パラフィンの合計１００質量部に対して５．０質量部以内、より好ましくは２．５質量部以内であれば、他の樹脂成分を配合しても許容される。なお、本発明の一実施形態に係る延伸多孔性フィルムおよび樹脂組成物は、熱可塑性エラストマーを含まないものであってもよい。 <1-4. Other ingredients>
The resin composition may further contain an additive used in a normal resin composition. Such additives include antioxidants, heat stabilizers, light stabilizers, ultraviolet light absorbers, neutralizing agents, lubricants, antifogging agents, antiblocking agents, antistatic agents, slip agents, coloring agents, plasticizers, etc. It can be mentioned. In addition, in the resin composition, a small amount of a resin component other than that constituting the polyolefin resin and the liquid paraffin may be blended within a range not impairing the effects of the present invention. Specifically, if it is within 5.0 parts by mass, more preferably within 2.5 parts by mass with respect to a total of 100 parts by mass of the polyolefin resin and the liquid paraffin, it is acceptable even if other resin components are blended. Ru. In addition, the stretched porous film and the resin composition according to an embodiment of the present invention may not contain a thermoplastic elastomer.
　＜１－５．延伸多孔性フィルムの物性＞
　延伸多孔性フィルムの透湿度は、１４００ｇ／ｍ２・２４ｈ以上であることが好ましく、１６００ｇ／ｍ２・２４ｈ以上であることがより好ましい。透湿度が上記範囲にあることにより、通気性および透湿性に優れる。例えば、延伸多孔性フィルムを紙おむつのバックシートとして用いた場合には、着用時の蒸れを防止することができる。なお、透湿度の上限は、機械特性、耐水性および耐液漏れ性の観点から、１００００ｇ／ｍ２・２４ｈ以下であることが好ましく、４０００ｇ／ｍ２・２４ｈ以下であることがより好ましい。透湿度の上限を４０００ｇ／ｍ２・２４ｈ以下とすることにより、上記延伸多孔性フィルムを用いたおむつは着用時に液漏れが発生するおそれがより低くなる。また、特許文献１に示されたフィルムの透湿度はいずれも４０００ｇ／ｍ２・２４ｈを超えているため、おむつなどに用いると着用時に液漏れが発生するおそれがあると考えられる。 <1-5. Physical Properties of Stretched Porous Film>
The moisture permeability of the stretched porous film is preferably 1400 g / m 2 · 24 h or more, and more preferably 1600 g / m 2 · 24 h or more. When the moisture permeability is in the above range, the air permeability and the moisture permeability are excellent. For example, when the stretched porous film is used as a back sheet of a paper diaper, it is possible to prevent the stuffiness at the time of wearing. The upper limit of moisture permeability, mechanical properties, from the viewpoints of water resistance and liquid leakage resistance is preferably not more than 10000g / m 2 · 24h, more preferably at most 4000g / m 2 · 24h. By setting the upper limit of the moisture permeability to 4000 g / m 2 · 24 h or less, the diaper using the stretched porous film has a lower possibility of liquid leakage when worn. Moreover, since the moisture permeability of the film shown by patent document 1 is over 4000 g / m 2 · 24 h in all cases, it is considered that there is a possibility that liquid leakage may occur at the time of wearing when used for a diaper or the like.
　透湿度は、ＡＳＴＭ　Ｅ９６に準じて、４０℃、相対湿度６０％、測定時間２４時間、純水法の条件で測定される。なお、本明細書において、透湿度は、延伸多孔性フィルムから採取した１０ｃｍ×１０ｃｍのサンプル１０枚の平均値である。 The moisture permeability is measured according to ASTM E96 under conditions of a pure water method at 40 ° C., 60% relative humidity, and a measuring time of 24 hours. In the present specification, the moisture permeability is the average value of 10 samples of 10 cm × 10 cm collected from the stretched porous film.
　延伸多孔性フィルムの５％伸張強度は、０．３Ｎ／２５ｍｍ以上、２．５Ｎ／２５ｍｍ未満であることが好ましく、０．５Ｎ／２５ｍｍ以上、２．３Ｎ／２５ｍｍ以下であることがより好ましい。５％伸張強度が小さいほど、柔軟である。５％伸張強度が２．５Ｎ／２５ｍｍ未満であれば、より柔軟性を付与することができる。５％伸張強度が０．３Ｎ／２５ｍｍ以上であれば、二次加工時に機械方向にかかるライン張力に対するフィルムの伸びを抑えることができる。 The 5% tensile strength of the stretched porous film is preferably 0.3 N / 25 mm or more and less than 2.5 N / 25 mm, and more preferably 0.5 N / 25 mm or more and 2.3 N / 25 mm or less. The smaller the 5% tensile strength, the more flexible it is. If the 5% tensile strength is less than 2.5 N / 25 mm, more flexibility can be imparted. If the 5% tensile strength is 0.3 N / 25 mm or more, it is possible to suppress the film elongation to the line tension applied in the machine direction at the time of secondary processing.
　５％伸張強度は、ＪＩＳ　Ｋ　７１２７に準じて、サンプルをチャック間距離５０ｍｍ、引張り速度２００ｍｍ/ｍｉｎ．で機械方向に引張り、サンプルが５％伸びた時の機械方向の強度として測定される。すなわち、５％伸張強度は、チャック間距離が２．５ｍｍ伸びた時の機械方向の応力として測定される。また、本明細書において、５％伸張強度は、延伸多孔性フィルムから採取された幅２５ｍｍ、機械方向の長さ１５０ｍｍのサンプルについて測定された値である。 According to JIS K 7127, the 5% tensile strength of the sample at a chuck distance of 50 mm and a tensile speed of 200 mm / min. The tensile strength in the machine direction is measured as the strength in the machine direction when the sample is stretched 5%. That is, 5% tensile strength is measured as stress in the machine direction when the distance between chucks is expanded by 2.5 mm. Further, in the present specification, 5% tensile strength is a value measured for a sample having a width of 25 mm and a length in the machine direction of 150 mm collected from a stretched porous film.
　樹脂組成物のメルトマスフローレイトは、２．０ｇ／１０ｍｉｎ．以上であることが好ましく、２．０ｇ／１０ｍｉｎ．以上、６．０ｇ／１０ｍｉｎ．以下であることがより好ましく、２．０ｇ／１０ｍｉｎ．以上、５．０ｇ／１０ｍｉｎ．以下であることがさらに好ましい。メルトマスフローレイトが上記範囲であれば、より安定した製膜を行うことが可能である。メルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であれば、製膜時押出機の樹脂圧力が抑えられ、製膜への悪影響を防ぐことができる。また、メルトマスフローレイトが６．０ｇ／１０ｍｉｎ．以下であれば、Ｔダイで製膜する際のネックインをより抑えることができる。そのため、必要とされる製品幅を容易に得ることができる。また、メルトマスフローレイトと５％伸張強度とは相関する傾向がある。メルトマスフローレイトを小さくすると、５％伸張強度が高くなり、それゆえに柔軟性に乏しい延伸多孔性フィルムとなりやすい。樹脂組成物のメルトマスフローレイトは、ＪＩＳ　Ｋ　７２１０に準じて、１９０℃でＡ法にて測定される。 The melt mass flow rate of the resin composition is 2.0 g / 10 min. It is preferable that it is more than 2.0 g / 10 min. Above, 6.0 g / 10 min. Or less, more preferably 2.0 g / 10 min. Above, 5.0 g / 10 min. It is more preferable that it is the following. If the melt mass flow rate is in the above range, more stable film formation can be performed. The melt mass flow rate is 2.0 g / 10 min. If it is the above, the resin pressure of the film forming extruder can be suppressed, and an adverse effect on film forming can be prevented. Moreover, the melt mass flow rate is 6.0 g / 10 min. If it is the following, the neck-in at the time of forming into a film with T-die can be suppressed more. Therefore, the required product width can be easily obtained. Also, melt mass flow rate and 5% tensile strength tend to be correlated. Decreasing the melt mass flow rate increases the 5% tensile strength and therefore tends to result in a stretched porous film with poor flexibility. The melt mass flow rate of the resin composition is measured by Method A at 190 ° C. according to JIS K 7210.
　延伸多孔性フィルムの通気度は、３００秒／１００ｍＬ以上、２０００秒／１００ｍＬ以下であることが好ましく、４００秒／１００ｍＬ以上、１６００秒／１００ｍＬ以下であることがより好ましく、４００秒／１００ｍＬ以上、１１００秒／１００ｍＬ以下であることがさらに好ましい。通気度は値が小さいほど、気体を通過させやすいことを表す。通気度が上記範囲であれば、延伸多孔性フィルムを紙おむつのバックシートとして用いた場合に、着用時の蒸れを防止することができる。通気度は、ＪＩＳ　Ｐ　８１１７に準じて、王研式試験機法で測定される。 The air permeability of the stretched porous film is preferably 300 seconds / 100 mL or more and 2000 seconds / 100 mL or less, more preferably 400 seconds / 100 mL or more and 1600 seconds / 100 mL or less, and 400 seconds / 100 mL or more. More preferably, it is 1100 seconds / 100 mL or less. The lower the permeability, the easier it is for gas to pass. When the air permeability is in the above-mentioned range, when the stretched porous film is used as a back sheet of a paper diaper, it is possible to prevent stuffiness when worn. The air permeability is measured by the Oken type tester according to JIS P 8117.
　延伸多孔性フィルムの機械方向の熱収縮率は、５．０％以下であることが好ましく、３．５％以下であることがより好ましい。５％伸張強度が大きいとともに、機械方向の熱収縮率が５．０％以下であれば、二次加工時に機械方向にかかるライン張力に対するフィルムの伸びを、より抑えることができる。機械方向の熱収縮率は０％に近いほど好ましいが、実用的には０．５％以上である。 The heat shrinkage rate in the machine direction of the stretched porous film is preferably 5.0% or less, and more preferably 3.5% or less. If the 5% tensile strength is high and the heat shrinkage rate in the machine direction is 5.0% or less, the film elongation to the line tension applied in the machine direction at the time of secondary processing can be further suppressed. The heat shrinkage rate in the machine direction is preferably as close to 0% as possible, but is practically 0.5% or more.
　機械方向の熱収縮率は、以下の方法によって測定される。延伸多孔性フィルムから、１５ｃｍ×１５ｃｍのサンプルを採取する。機械方向に標線間が１０ｃｍとなるよう、このサンプルに標線を入れる。このサンプルを５０℃で２４時間放置した後、室温に冷却して標線間の長さを測定する。機械方向の熱収縮率は下記式Ｉより求められる。
式Ｉ：機械方向の熱収縮率（％）＝{（１０ｃｍ－冷却後の標線間の長さ（ｃｍ））／１０ｃｍ}×１００。 The heat shrinkage rate in the machine direction is measured by the following method. A sample of 15 cm × 15 cm is taken from the stretched porous film. Make a mark on this sample so that there is 10 cm between marks in the machine direction. The sample is left at 50 ° C. for 24 hours, then cooled to room temperature and the length between marks is measured. The heat shrinkage rate in the machine direction can be obtained from the following formula I.
Formula I: Thermal contraction rate in machine direction (%) = {(10 cm−length between marked lines after cooling (cm)) / 10 cm} × 100.
　目付は、１０ｇ／ｍ２以上、３５ｇ／ｍ２以下であることが好ましく、１１ｇ／ｍ２以上、３２ｇ／ｍ２以下であることがより好ましく、１２ｇ／ｍ２以上、３０ｇ／ｍ２以下であることがさらに好ましい。目付が上記範囲であることにより、通気性、透湿性および機械強度に優れる延伸多孔性フィルムが得られる。目付が１０ｇ／ｍ２以上であれば、フィルムの機械強度を高めることができる。また、目付が３５ｇ／ｍ２以下であれば、十分な透湿性を得ることができる。 The basis weight is preferably 10 g / m 2 or more and 35 g / m 2 or less, more preferably 11 g / m 2 or more and 32 g / m 2 or less, and 12 g / m 2 or more and 30 g / m 2 or less It is further preferred that When the weight per unit area is in the above range, a stretched porous film excellent in air permeability, moisture permeability and mechanical strength can be obtained. When the basis weight is 10 g / m 2 or more, the mechanical strength of the film can be increased. Moreover, if the fabric weight is 35 g / m 2 or less, sufficient moisture permeability can be obtained.
　〔２．延伸多孔性フィルムの製造方法〕
　本発明の一実施形態に係る延伸多孔性フィルムの製造方法は、密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を混合して樹脂組成物を得る混合工程と、前記樹脂組成物をフィルム状に成形する成形工程と、前記成形工程によって得られたフィルムを少なくとも機械方向に延伸することで多孔化させる多孔化工程と、を含む。このように特定の物性を有するポリオレフィン系樹脂に対して、流動パラフィンを特定の質量比にて組み合わせることにより、耐水性に加えて所望の柔軟性を有する延伸多孔性フィルムが得られる。特定の範囲のメルトマスフローレイトを備えた樹脂組成物は、樹脂組成物の流動性が良好となり、柔軟性を有した延伸多孔性フィルムが得られる。また、特定の組成の樹脂組成物を含むフィルムを延伸して多孔化することにより、所望の通気性を有する延伸多孔性フィルムが得られる。それゆえ、通気性、耐水性および柔軟性を兼ね備えた延伸多孔性フィルムを実現できる。なお、〔１．延伸多孔性フィルム〕で既に説明した事項については、以下では説明を省略し、適宜、上述の記載を援用する。 [2. Method for producing stretched porous film]
Method for producing a stretched porous film according to an embodiment of the present invention has a density of 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin-based resin 100 parts by weight A mixing step of mixing a liquid paraffin of 5.0 parts by mass or more and 20 parts by mass or less and an inorganic filler to obtain a resin composition, and a forming step of forming the resin composition into a film shape; And V. a porosification step in which the film obtained by the molding step is made porous by drawing at least in the machine direction. Thus, by combining liquid paraffin with a specific weight ratio to a polyolefin resin having specific physical properties, a stretched porous film having desired flexibility in addition to water resistance can be obtained. A resin composition having a melt mass flow rate in a specific range improves the flowability of the resin composition, and a flexible stretched porous film is obtained. Further, by stretching and porosifying a film containing a resin composition of a specific composition, a stretched porous film having desired air permeability can be obtained. Therefore, a stretched porous film having both air permeability, water resistance and flexibility can be realized. [1. About the matter already demonstrated by stretched porous film], below, description is abbreviate | omitted and the above-mentioned description is suitably used.
　＜２－１．混合工程＞
　混合工程は、密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を混合して樹脂組成物を得る工程である。まず、ポリオレフィン系樹脂、流動パラフィン、無機充填剤、さらには必要に応じて配合する添加剤を混合する。混合方法は特に限定されず、公知の方法が採用できる。例えば、ヘンシェルミキサー、スーパーミキサー、またはタンブラーミキサー等の混合機を用いて５分～１時間程度混合することが好ましい。 <2-1. Mixing process>
Mixing step has a density of 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, below 20 parts by weight In this step, a liquid paraffin and an inorganic filler are mixed to obtain a resin composition. First, a polyolefin resin, liquid paraffin, an inorganic filler, and, if necessary, additives to be blended are mixed. The mixing method is not particularly limited, and known methods can be adopted. For example, it is preferable to mix for about 5 minutes to 1 hour using a mixer such as a Henschel mixer, a super mixer, or a tumbler mixer.
　得られた混合物は一般に高混練タイプの２軸押出機、またはタンデム型混練機等の混練機を用いて、ストランドカット、ホットカット、またはアンダーウォーターカット等の方法で混練し、ペレット化できる。予め混合および混練し、ペレット化することにより、樹脂組成物の均一な分散を促すことができるため、好ましい。また、樹脂組成物の配合によっては、混合なしに直接混練機に投入し、ペレット化することもできる。 The obtained mixture can be generally kneaded and pelletized by a method such as strand cut, hot cut or underwater cut using a kneader such as a high kneader type twin screw extruder or a tandem type kneader. It is preferable because mixing and kneading in advance and pelletization can promote uniform dispersion of the resin composition. Further, depending on the composition of the resin composition, it can be directly put into a kneader without mixing and pelletized.
　＜２－２．成形工程＞
　成形工程は、前記樹脂組成物をフィルム状に成形する工程である。上述のように得られたペレットを、押出機の先端に装着したサーキュラダイまたはＴダイによってフィルム状に成形することが好ましい。このとき、Ｔダイ法を用いる場合の冷却方法は、特に制限されず、ニップルロール法、エアナイフ法、またはエアチャンバー法等の公知の方法が採用できる。なお、樹脂組成物の配合次第によっては、混合および混練なしに直接押出機に樹脂組成物を投入し、フィルムを成形することもできる。 <2-2. Molding process>
The molding step is a step of molding the resin composition into a film. The pellets obtained as described above are preferably formed into a film by a circular die or a T-die attached to the tip of an extruder. At this time, the cooling method in the case of using the T-die method is not particularly limited, and a known method such as a nipple roll method, an air knife method, or an air chamber method can be adopted. Depending on the composition of the resin composition, the film may be formed by directly charging the resin composition into an extruder without mixing and kneading.
　＜２－３．多孔化工程＞
　多孔化工程は、前記成形工程によって得られたフィルムを少なくとも機械方向に延伸することで多孔化させる工程である。成形工程によって得られたフィルムを、延伸することにより、樹脂成分（前記ポリオレフィン系樹脂および前記流動パラフィン）と無機充填剤との界面が剥離する。そして、剥離した界面に微小な空隙ができ、該空隙がフィルムの厚さ方向に貫通した連通孔を形成することにより延伸多孔性フィルムとなる。延伸は、ロール延伸法またはテンター延伸法等の公知の方法により行うことができる。また、延伸は、一軸延伸であってもよく、二軸延伸であってもよい。 <2-3. Porous process>
The porosifying step is a step in which the film obtained by the forming step is rendered porous by drawing at least in the machine direction. By stretching the film obtained by the forming step, the interface between the resin component (the polyolefin resin and the liquid paraffin) and the inorganic filler is peeled off. Then, a minute void is formed at the peeled interface, and the void forms a communicating hole penetrating in the thickness direction of the film, whereby a stretched porous film is formed. Stretching can be performed by a known method such as roll stretching or tenter stretching. The stretching may be uniaxial stretching or biaxial stretching.
　なお、前記多孔化工程における機械方向の延伸倍率が以下式ＩＩにて示されることが好ましい：
　１．４≦Ｙ≦０．０７５Ｘ＋１．８　　　・・・（式ＩＩ）
　（式中、Ｘはポリオレフィン系樹脂１００質量部に対する流動パラフィンの配合割合（質量部）を示し、Ｙは延伸倍率（倍）を示す）。 In addition, it is preferable that the draw ratio of the machine direction in the said porosification process is shown by the following formula II:
1.4 ≦ Y ≦ 0.075X + 1.8 (Formula II)
(In the formula, X represents a blending ratio (parts by mass) of liquid paraffin to 100 parts by mass of a polyolefin resin, and Y represents a stretching ratio (fold)).
　上記式ＩＩが成立する条件において延伸を実施することにより、得られるフィルムは、柔軟性を有したまま十分に延伸され、厚みのムラが発生し難く、かつ、引裂強度が良好であり、十分な数およびサイズの孔が形成される。従って、このような延伸倍率であれば、通気性、透湿性および柔軟性を兼ね備えた延伸多孔性フィルムをより容易に得ることができる。前記延伸は一段延伸でも多段延伸でもよい。 By carrying out the stretching under the condition that the above-mentioned formula II is established, the obtained film is sufficiently stretched while having flexibility, so that the thickness unevenness is unlikely to occur, and the tear strength is good and sufficient. Holes of number and size are formed. Therefore, with such a stretching ratio, a stretched porous film having both air permeability, moisture permeability and flexibility can be obtained more easily. The stretching may be single-stage stretching or multi-stage stretching.
　延伸温度は、常温以上、樹脂組成物の軟化点未満の温度範囲であることが好ましい。延伸温度が常温以上であれば、延伸ムラが生じ難いため、厚みが均一になりやすい。また、延伸温度が軟化点未満であれば、延伸多孔性フィルムが融解することを防ぐことができる。よって、延伸多孔性フィルムの孔が潰れ、通気性および透湿性が低下することを防ぐことができる。延伸温度は用いる樹脂組成物の物性と延伸倍率との組合せにより適宜調整することができる。 It is preferable that extending | stretching temperature is a temperature range above normal temperature and less than the softening point of a resin composition. If the stretching temperature is equal to or higher than normal temperature, stretching unevenness is unlikely to occur, so the thickness tends to be uniform. In addition, when the stretching temperature is less than the softening point, it is possible to prevent the stretched porous film from melting. Therefore, it is possible to prevent the pores of the stretched porous film from being crushed and the air permeability and the moisture permeability being lowered. The stretching temperature can be appropriately adjusted by the combination of the physical properties of the resin composition used and the stretching ratio.
　＜２－４．熱固定工程＞
　前記製造方法は、熱固定工程を含んでいてもよい。熱固定工程は、延伸方向の熱収縮を抑えるために、延伸後の延伸多孔性フィルムを熱固定する工程である。熱固定とは、延伸後のフィルムに延伸による緊張状態を維持した状態で、寸法を変化させない環境下で行う加熱処理のことである。その結果、熱固定により、保管時の弾性回復、並びに熱による収縮および巻き絞まり等を抑制することができる。 <2-4. Heat setting process>
The manufacturing method may include a heat setting step. The heat setting step is a step of heat setting the stretched porous film after stretching in order to suppress heat shrinkage in the stretching direction. The heat setting is a heat treatment performed in an environment in which the dimensions are not changed while maintaining a stretched state of the stretched film. As a result, it is possible to suppress elastic recovery during storage, contraction due to heat, squeezing, etc. by heat setting.
　延伸方法としてロール延伸法を採用した場合の熱固定方法として、延伸後のフィルムを、加熱したロール（アニールロール）により加熱する方法が挙げられる。また、延伸方法としてテンター延伸法を採用した場合の熱固定方法として、延伸後のフィルムをテンター出口付近でフィルムを加熱する方法が挙げられる。 As a heat setting method in the case of adopting a roll drawing method as a drawing method, a method of heating a film after drawing with a heated roll (annealing roll) can be mentioned. In addition, as a heat setting method in the case where the tenter stretching method is adopted as the stretching method, a method of heating the film after stretching in the vicinity of the tenter outlet may be mentioned.
　熱固定の温度は、７０℃以上、９５℃以下であることが好ましく、８０℃以上、９５℃以下であることが好ましい。熱固定温度が７０℃以上であれば、十分な熱固定により、熱収縮を抑えることができる。また、熱固定温度が９５℃以下であれば、熱によって延伸多孔性フィルムの孔が潰れることを、より防ぐことができる。 The heat setting temperature is preferably 70 ° C. or more and 95 ° C. or less, and more preferably 80 ° C. or more and 95 ° C. or less. If the heat setting temperature is 70 ° C. or more, heat shrinkage can be suppressed by sufficient heat setting. In addition, when the heat setting temperature is 95 ° C. or less, the pores of the stretched porous film can be further prevented from being crushed by heat.
　熱固定の時間は、０．２秒以上であることが好ましく、０．５秒以上であることがより好ましく、１．０秒以上であることがさらに好ましい。熱固定の時間が０．２秒以上であれば、十分な熱固定により、熱収縮を抑えることができる。また、熱固定の時間は、２０秒以下であることが好ましく、１５秒以下であることがより好ましい。熱固定温度との組合せにもよるため一概には言えないが、熱固定の時間が２０秒以下であれば、延伸多孔性フィルムが融解することによって孔が潰れることを、より防ぐことができる。従って通気性および透湿性が低下することを防ぐことができる。 The heat setting time is preferably 0.2 seconds or more, more preferably 0.5 seconds or more, and still more preferably 1.0 seconds or more. If the heat setting time is 0.2 seconds or more, the heat shrinkage can be suppressed by sufficient heat setting. The heat setting time is preferably 20 seconds or less, more preferably 15 seconds or less. Although it depends on the combination with the heat setting temperature, it can not be said in general, but if the heat setting time is 20 seconds or less, it is possible to prevent the pores from being crushed by melting of the stretched porous film. Therefore, the air permeability and the moisture permeability can be prevented from being lowered.
　前記熱固定の時間は、延伸多孔性フィルムが熱固定温度で保持される時間である。例えば、ロール延伸法を採用した場合、フィルムがアニールロールと接している時間をいう。アニールロールの本数は特に制限されないが、２本以上ある場合、熱固定の時間は延伸多孔性フィルムが各アニールロールに接する時間の和である。また、テンター延伸法を採用した場合、熱固定の時間はテンター出口において熱固定温度で加熱され、維持される時間を示す。熱固定を複数回に分割して加熱する場合、各々加熱された時間の和である。 The heat setting time is the time for which the stretched porous film is kept at the heat setting temperature. For example, when the roll stretching method is adopted, it refers to the time during which the film is in contact with the annealing roll. The number of annealing rolls is not particularly limited, but in the case of two or more, the heat setting time is the sum of the time when the stretched porous film is in contact with each annealing roll. Also, when the tenter stretching method is adopted, the time of heat setting indicates the time of heating and maintaining at the heat setting temperature at the tenter outlet. When heat setting is divided into multiple times and heated, it is the sum of each heating time.
　本発明は上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.
　以下、実施例に基づいて本発明をより詳細に説明するが、本発明は以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.
　〔評価方法〕
　後述の実施例および比較例の延伸多孔性フィルムの物性値は以下に示す方法によって測定したものである。 〔Evaluation method〕
The physical-property value of the extending | stretching porous film of the below-mentioned Example and a comparative example is measured by the method shown below.
　（１）メルトマスフローレイト
　樹脂組成物のメルトマスフローレイトはＪＩＳ　Ｋ　７２１０に従い、測定温度として１９０℃を選択し、Ａ法で測定した。なお、以下では、メルトマスフローレイトをＭＩ（メルト・インデックス）とも称する。 (1) Melt Mass Flow Rate The melt mass flow rate of the resin composition was measured according to JIS K 7210, at 190 ° C. as the measurement temperature, and measured by method A. In the following, melt mass flow rate is also referred to as MI (melt index).
　（２）目付
　延伸多孔性フィルムから１０ｃｍ×１０ｃｍのサンプルを切り取り、天秤で質量を測定した。このサンプルの面積および質量から、目付を求めた。 (2) Fabric weight A sample of 10 cm × 10 cm was cut out of the stretched porous film, and the mass was measured by a balance. The basis weight was determined from the area and mass of this sample.
　（３）透湿度
　延伸多孔性フィルムから、１０ｃｍ×１０ｃｍのサンプルを１０枚採取した。これらについて、ＡＳＴＭ　Ｅ９６に準じて、４０℃、相対湿度６０％、測定時間２４時間、純水法の条件で透湿度を測定し、その平均値を求めた。 (3) Moisture Permeability Ten sheets of 10 cm × 10 cm were collected from the stretched porous film. With respect to these, according to ASTM E96, the moisture permeability was measured under the conditions of a pure water method at 40 ° C., a relative humidity of 60%, and a measurement time of 24 hours, and the average value was determined.
　（４）通気度
　通気度はＪＩＳ　Ｐ　８１１７に準じて、王研式試験機法で測定した。 (4) Permeability Permeability was measured by the Oken type tester according to JIS P 8117.
　（５）５％伸張強度
　ＪＩＳ　Ｋ　７１２７に準じて、延伸多孔性フィルムから、幅２５ｍｍ、機械方向の長さ１５０ｍｍのサンプルを採取した。このサンプルをチャック間距離５０ｍｍ、引張り速度２００ｍｍ/ｍｉｎ．で機械方向に引張り、サンプルが５％伸びた時の機械方向の強度を５％伸張強度として測定した。すなわち、チャック間距離が２．５ｍｍ伸びた時の機械方向の応力を測定した。 (5) 5% tensile strength According to JIS K 7127, a sample having a width of 25 mm and a machine direction length of 150 mm was collected from the stretched porous film. This sample was subjected to a chuck distance of 50 mm, a pulling speed of 200 mm / min. The tensile strength in the machine direction was measured as 5% tensile strength when the sample was stretched 5%. That is, the stress in the machine direction was measured when the distance between chucks was increased by 2.5 mm.
　（６）機械方向の熱収縮率
　延伸多孔性フィルムから、１５ｃｍ×１５ｃｍのサンプルを採取した。機械方向に標線間が１０ｃｍとなるよう、このサンプルに標線を入れた。このサンプルを５０℃で２４時間放置した後、室温に冷却して標線間の長さを測定した。機械方向の熱収縮率を下記数式（式Ｉ）より求めた。
式Ｉ：機械方向の熱収縮率（％）＝{（１０ｃｍ－冷却後の標線間の長さ（ｃｍ））／１０ｃｍ}×１００。 (6) Thermal contraction rate in the machine direction A 15 cm × 15 cm sample was taken from the stretched porous film. The samples were marked so that there was 10 cm between them in the machine direction. The sample was left at 50 ° C. for 24 hours, cooled to room temperature, and the length between the marked lines was measured. The heat shrinkage rate in the machine direction was determined by the following formula (Formula I).
Formula I: Thermal contraction rate in machine direction (%) = {(10 cm−length between marked lines after cooling (cm)) / 10 cm} × 100.
　〔用いた成分〕
　Ａ：線形低密度ポリエチレン［ダウケミカル（株）製、商品名：ダウレックス２０４７、密度：０．９１７ｇ／ｃｍ３、ＭＩ：２．３ｇ／１０ｍｉｎ．］
　Ｂ：線形低密度ポリエチレン［ダウケミカル（株）製、商品名：ダウレックス２０３５Ｇ、密度：０．９１９ｇ／ｃｍ３、ＭＩ：６．０ｇ／１０ｍｉｎ．］
　Ｃ：線形低密度ポリエチレン［ダウケミカル（株）製、商品名：ダウレックス２０３６Ｐ、密度：０．９３５ｇ／ｃｍ３、ＭＩ：２．５ｇ／１０ｍｉｎ．］
　Ｄ：線形低密度ポリエチレン［ダウケミカル（株）製、商品名：ダウレックス２０４５Ｇ、密度：０．９２０ｇ／ｃｍ３、ＭＩ：１．０ｇ／１０ｍｉｎ．］
　Ｅ：分岐状低密度ポリエチレン［三井・デュポンポリケミカル（株）製、商品名：ミラソン１６Ｐ、密度：０．９１７ｇ／ｃｍ３、ＭＩ：３．７ｇ／１０ｍｉｎ．］
　Ｆ：超低密度ポリエチレン[ダウケミカル（株）製、商品名：アテイン４６０７ＧＣ、密度０．９０４ｇ／ｃｍ３、ＭＩ：４．０ｇ／１０ｍｉｎ．]
　Ｇ：高密度ポリエチレン［東ソー（株）製、商品名：ニポロンハード４２００、密度：０．９６１ｇ／ｃｍ３、ＭＩ：２．３ｇ／１０ｍｉｎ．］
　Ｈ：流動パラフィン［和光純薬工業（株）製、商品名：流動パラフィン、密度：０．８６０～０．８９０ｇ／ｃｍ３］
　Ｉ：流動パラフィン［和光純薬工業（株）製、商品名：流動パラフィン、密度：０．８２５～０．８５０ｇ／ｃｍ３］
　Ｊ：流動パラフィン［和光純薬工業（株）製、商品名：流動パラフィン、密度：０．８００～０．８３５ｇ／ｃｍ３］
　Ｋ：パラフィン［和光純薬工業（株）製、商品名：パラフィン、融点：４２～４４℃、密度：０．９００ｇ／ｃｍ３］
　Ｌ：水素添加ポリブタジエン［日本曹達（株）製、商品名：Ｎｉｓｓｏ－ＰＢ　ＢＩ－２０００、密度：０．８６０ｇ／ｃｍ３］
　Ｍ：ポリブテン[日油（株）製、商品名：ポリブテン３Ｎ、密度：０．８８０ｇ／ｃｍ３]
　Ｎ：水素添加ポリブテン［日油（株）製、商品名：パールリーム４、密度：０．７９３ｇ／ｃｍ３]
　Ｏ：炭酸カルシウム［（株）イメリスミネラルズ製、商品名：ＦＬ－５２０］
　Ｐ：添加剤［酸化チタン（ハンツマン（株）製、商品名：ＴＲ２８）５０質量％と、ヒンダードフェノール系熱安定剤（チバ・ジャパン（株）製、商品名：ＩＲＧＡＮＯＸ３１１４）２０質量％と、リン系熱安定剤（チバ・ジャパン（株）製、商品名：ＩＲＧＡＦＯＳ１６８）３０質量％との混合物］。 [Component used]
A: Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2047, density: 0.917 g / cm 3 , MI: 2.3 g / 10 min. ]
B: Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2035 G, density: 0.919 g / cm 3 , MI: 6.0 g / 10 min. ]
C: Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2036P, density: 0.935 g / cm 3 , MI: 2.5 g / 10 min. ]
D: Linear low density polyethylene [Dow Chemical Co., Ltd., trade name: Dowrex 2045 G, density: 0.920 g / cm 3 , MI: 1.0 g / 10 min. ]
E: Branched low density polyethylene [Mitsui-Dupont Polychemicals Co., Ltd., trade name: Mirason 16P, density: 0.917 g / cm 3 , MI: 3.7 g / 10 min. ]
F: Ultra-low density polyethylene [Dow Chemical Co., Ltd., trade name: Atein 4607 GC, density 0.904 g / cm 3 , MI: 4.0 g / 10 min. ]
G: High density polyethylene [manufactured by Tosoh Corp., trade name: Nipolon Hard 4200, density: 0.961 g / cm 3 , MI: 2.3 g / 10 min. ]
H: liquid paraffin [manufactured by Wako Pure Chemical Industries, Ltd., trade name: liquid paraffin, density: 0.860 to 0.890 g / cm 3 ]
I: liquid paraffin [manufactured by Wako Pure Chemical Industries, Ltd., trade name: liquid paraffin, density: 0.825 to 0.850 g / cm 3 ]
J: Liquid paraffin [manufactured by Wako Pure Chemical Industries, Ltd., trade name: liquid paraffin, density: 0.800 to 0.835 g / cm 3 ]
K: Paraffin (manufactured by Wako Pure Chemical Industries, Ltd., trade name: Paraffin, melting point: 42 to 44 ° C., density: 0.900 g / cm 3 )
L: Hydrogenated polybutadiene [manufactured by Nippon Soda Co., Ltd., trade name: Nisso-PB BI-2000, density: 0.860 g / cm 3 ]
M: polybutene (manufactured by NOF Corporation, trade name: polybutene 3N, density: 0.880 g / cm 3 )
N: Hydrogenated polybutene (manufactured by NOF Corporation, trade name: Pearl Reme 4, density: 0.793 g / cm 3 )
O: Calcium carbonate [manufactured by Imerys Minerals, trade name: FL-520]
P: Additive [Titanium oxide (Huntsman Co., Ltd., trade name: TR28) 50% by mass, and hindered phenol heat stabilizer (Ciba Japan Co., Ltd., trade name: IRGANOX 3114) 20% by mass, Mixture with a phosphorus-based heat stabilizer (Ciba Japan Ltd., trade name: IRGAFOS 168) and 30% by mass].
　〔実施例１〕
　表１に記載のポリオレフィン系樹脂、炭化水素、無機充填剤および添加剤を混合した樹脂組成物とした。それを造粒し、次いで、フィルム形成を行った。 Example 1
It was set as the resin composition which mixed the polyolefin resin of Table 1, hydrocarbon, an inorganic filler, and an additive. It was granulated and then film formation was performed.
　造粒（ペレットの作製）は、以下のように行った。ベント付φ３０ｍｍ二軸押出機を用いて、シリンダー温度１６０℃で前記樹脂組成物をストランド状に押し出し、水槽で冷却した。その後、押し出された樹脂組成物を約５ｍｍにカットし、乾燥してペレットを作製した。 Granulation (preparation of pellets) was performed as follows. The resin composition was extruded into strands at a cylinder temperature of 160 ° C. using a vented φ30 mm twin-screw extruder, and cooled in a water bath. Thereafter, the extruded resin composition was cut to about 5 mm and dried to prepare pellets.
　次に、前記ペレットからφ４００ｍｍＴダイ製膜機を用いてフィルムを成形した。ここで、リップクリアランス：１．５ｍｍ、ダイ温度：２００℃、エアギャップ：１０５ｍｍ、引取速度：１０ｍ/ｍｉｎ．、キャストロール温度：２０℃であった。得られたフィルムをさらに、４０℃に設定したロール延伸機で機械方向のみ一軸延伸（延伸倍率：１．８倍）し、次いで９０℃に設定した熱セットロールでインラインアニーリングした（熱固定時間４秒）。その熱固定時の機械方向の熱収縮率は８％であった。 Next, a film was formed from the pellets using a φ400 mm T film forming machine. Here, lip clearance: 1.5 mm, die temperature: 200 ° C., air gap: 105 mm, take-up speed: 10 m / min. , Cast roll temperature: 20 ° C. The obtained film was further uniaxially stretched (stretching ratio: 1.8 times) only in the machine direction by a roll stretcher set at 40 ° C., and then inline annealing was performed by a heat set roll set at 90 ° C. (heat setting time 4) Seconds). The heat shrinkage rate in the machine direction at the time of heat setting was 8%.
　実施例２～１３および比較例１～８においては、各成分の配合割合または延伸条件（延伸倍率もしくは熱固定温度）を表１および表２に記載のように変更した以外は、実施例１と同様にフィルムを形成した。
Figure JPOXMLDOC01-appb-T000001
 In Examples 2 to 13 and Comparative Examples 1 to 8, Example 1 is used except that the blending ratio of each component or the stretching condition (stretching ratio or heat setting temperature) is changed as described in Table 1 and Table 2. A film was formed as well.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
 　なお、「ポリオレフィン系樹脂：配合割合（質量％）」は樹脂組成物に含まれるポリオレフィン系樹脂１００質量％に対する各ポリエチレン系樹脂の配合割合を表す。「炭化水素：配合割合（質量部）」は、ポリオレフィン系樹脂１００質量部に対する炭化水素の配合割合を表す。炭酸カルシウムおよび添加剤の配合割合は、ポリオレフィン系樹脂と炭化水素との合計１００質量部に対する配合割合として記載されている。
Figure JPOXMLDOC01-appb-T000002
 In addition, "polyolefin resin: compounding ratio (mass%)" represents the compounding ratio of each polyethylene resin with respect to 100 mass% of polyolefin resin contained in a resin composition. "Hydrocarbon: blending ratio (parts by mass)" represents the blending ratio of hydrocarbons to 100 parts by mass of the polyolefin resin. The blending ratio of calcium carbonate and additives is described as a blending ratio with respect to a total of 100 parts by mass of the polyolefin resin and the hydrocarbon.
　また、延伸条件※１は延伸倍率１．８倍、熱固定温度９０℃を表す。延伸条件※２は延伸倍率３．２倍、熱固定温度９０℃を表す。延伸条件※３は延伸倍率２．５倍、熱固定温度９０℃を示す。延伸条件※４は延伸条件１．３倍、熱固定温度９０℃を示す。 The stretching condition * 1 represents a stretching ratio of 1.8 times and a heat setting temperature of 90 ° C. The stretching condition * 2 represents a stretching ratio of 3.2 times and a heat setting temperature of 90 ° C. The stretching condition * 3 indicates a stretching ratio of 2.5 times and a heat setting temperature of 90 ° C. The stretching condition * 4 indicates that the stretching condition is 1.3 times and the heat setting temperature is 90 ° C.
　〔結果〕
　実施例１～１３および比較例１～８で得られた延伸多孔性フィルムの目付、透湿度、通気度、５％伸張強度および熱収縮率の測定を行い、表３に示した。 〔result〕
The basis weight, moisture permeability, air permeability, 5% tensile strength and heat shrinkage of the stretched porous films obtained in Examples 1 to 13 and Comparative Examples 1 to 8 were measured, and the results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
 　実施例１～１３の延伸多孔性フィルムは、いずれも１４００ｇ／ｍ２・２４ｈ以上の良好な透湿度を示すとともに、良好な風合いを有していた。また、実施例１～８、および１０～１２の延伸多孔性フィルムは、５％伸張強度および熱収縮率について低い値を保持していた。さらに、本実施例１～８、および１０～１２の延伸多孔性フィルムは、いずれの延伸倍率も式ＩＩを満たす。
Figure JPOXMLDOC01-appb-T000003
 The stretched porous films of Examples 1 to 13 all exhibited good moisture permeability of at least 1400 g / m 2 · 24 h, and also had good texture. Also, the stretched porous films of Examples 1-8 and 10-12 maintained low values for 5% tensile strength and thermal shrinkage. Furthermore, in the stretched porous films of Examples 1 to 8 and 10 to 12, any stretching ratio satisfies Formula II.
　実施例３と４とでは、密度の違うポリオレフィン系樹脂を用いた。実施例４では、密度が０．９６１ｇ／ｃｍ３のポリエチレンを用いた。密度の高いポリエチレンを加えた実施例４では実施例３に比べ透湿度が高く、通気度が低い。また、実施例４は、５％伸長強度が高い結果になったが、比較例に比べて良好であった。 In Examples 3 and 4, polyolefin resins having different densities were used. In Example 4, polyethylene having a density of 0.961 g / cm 3 was used. In Example 4 to which high density polyethylene is added, the moisture permeability is higher and the air permeability is lower than Example 3. Moreover, although the result of 5% elongation strength was high in Example 4, it was better than the comparative example.
　実施例６～８を比較すると、流動パラフィンの密度の低下に伴い、通気度が低下し、透湿度および５％伸張強度が増加することがわかる。 Comparing Examples 6-8, it can be seen that as the density of liquid paraffin decreases, the air permeability decreases and the moisture permeability and 5% tensile strength increase.
　なお、延伸倍率が式ＩＩを満たさない実施例９および１３は、式ＩＩを満たす実施例１～８、および１０～１２に比べて、５％伸張強度が高いが、比較例に比べて透湿度、通気度、５％伸張強度および熱収縮率のバランスが良好であった。 In Examples 9 and 13 in which the draw ratio does not satisfy Formula II, the 5% tensile strength is higher than Examples 1 to 8 and 10 to 12 which satisfy Formula II, but the moisture permeability is higher than that of Comparative Example. The balance of air permeability, 5% tensile strength and heat shrinkage was good.
　また、実施例２、９、および１２は、同じ組成の延伸多孔性フィルムの延伸倍率を変更した。これらから、延伸倍率を上げることにより、透湿度が増加し、通気度および熱収縮率が低下していることがわかる。 Moreover, Examples 2, 9 and 12 changed the draw ratio of the stretched porous film of the same composition. From these, it can be seen that the moisture permeability is increased and the air permeability and the thermal contraction rate are decreased by increasing the draw ratio.
　比較例１では、炭化水素を用いなかった。その結果、得られた延伸多孔性フィルムは５％伸張強度が高く、柔軟性に乏しい延伸多孔性フィルムが得られた。 In Comparative Example 1, no hydrocarbon was used. As a result, the obtained stretched porous film had a high 5% tensile strength, and a stretched porous film poor in flexibility was obtained.
　比較例２～５では、炭化水素として流動パラフィン以外の炭化水素を用いた。その結果、炭化水素としてパラフィンを用いた比較例２、および炭化水素として水素添加ポリブテンを用いた比較例５では、５％伸張強度が高く、柔軟性に乏しい延伸多孔性フィルムが得られた。炭化水素として水素添加ポリブタジエンを用いた比較例３、および炭化水素としてポリブテンを用いた比較例４では、いずれも透湿度が低く、蒸れやすい延伸多孔性フィルムが得られた。 In Comparative Examples 2 to 5, hydrocarbons other than liquid paraffin were used as the hydrocarbons. As a result, in Comparative Example 2 in which paraffin was used as a hydrocarbon and Comparative Example 5 in which hydrogenated polybutene was used as a hydrocarbon, a stretched porous film having high 5% elongation strength and poor flexibility was obtained. In Comparative Example 3 in which hydrogenated polybutadiene was used as the hydrocarbon, and Comparative Example 4 in which polybutene was used as the hydrocarbon, the moisture permeability was low in any case, and a stretchable porous film which is easily steamed was obtained.
　比較例６では、ポリオレフィン系樹脂１００質量部に対して、密度が０．９６１ｇ／ｃｍ３のポリエチレンを７５質量％用いた。その結果、通気度が低く、透湿度および５％伸張強度が高い、柔軟性に乏しい延伸多孔性フィルムが得られた。 In Comparative Example 6, 75% by mass of polyethylene having a density of 0.961 g / cm 3 was used with respect to 100 parts by mass of the polyolefin resin. As a result, a less flexible stretched porous film with low air permeability, high moisture permeability and 5% tensile strength was obtained.
　比較例７では、メルトマスフローレイトの低いポリオレフィン系樹脂を用いた。その結果、得られた延伸多孔性フィルムは透湿度が低く、蒸れやすい延伸多孔性フィルムが得られた。 In Comparative Example 7, a polyolefin resin having a low melt mass flow rate was used. As a result, the obtained stretched porous film has a low moisture permeability, and a stretched porous film which is easy to steam is obtained.
　比較例８は、透湿度が低いため、通気度に劣る延伸多孔性フィルムとなった。 Comparative Example 8 was a stretched porous film inferior in air permeability because of low moisture permeability.
　〔まとめ〕
　〔１〕密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を含有する樹脂組成物より構成され、ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であり、ＡＳＴＭ　Ｅ９６に準じて４０℃、相対湿度６０％の条件で測定される透湿度が１４００ｇ／ｍ２・２４ｈ以上であることを特徴とする延伸多孔性フィルム。 [Summary]
[1] density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, is 20 parts by mass or less The resin composition is composed of a liquid paraffin and an inorganic filler, and the melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min. This is a stretched porous film characterized by having the moisture permeability of 1400 g / m 2 · 24 h or more measured under the conditions of 40 ° C. and 60% relative humidity according to ASTM E96.
　〔２〕ＪＩＳ　Ｋ　７１２７に準じて、チャック間距離５０ｍｍ、引張り速度２００ｍｍ/ｍｉｎ．で機械方向に引張り、チャック間距離が５％伸びた時の機械方向の強度が０．３Ｎ／２５ｍｍ以上、２．５Ｎ／２５ｍｍ未満であることを特徴とする〔１〕に記載の延伸多孔性フィルム。 [2] According to JIS K 7127, the distance between chucks is 50 mm, the tensile speed is 200 mm / min. Tensile strength in the machine direction when the distance between chucks is extended by 5% in the machine direction, and the tensile strength in the machine direction is 0.3 N / 25 mm or more and 2.5 N / 25 mm or less. the film.
　〔３〕ＪＩＳ　Ｐ　８１１７に準じて王研式試験機法で測定される通気度が３００秒／１００ｍＬ以上、２０００秒／１００ｍＬ以下であることを特徴とする〔１〕または〔２〕に記載の延伸多孔性フィルム。 [3] The air permeability measured by the Oken type tester according to JIS P 8117 is 300 seconds / 100 mL or more and 2000 seconds / 100 mL or less, according to [1] or [2]. Stretched porous film.
　〔４〕密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を混合して樹脂組成物を得る混合工程と、前記樹脂組成物をフィルム状に成形する成形工程と、前記成形工程によって得られたフィルムを少なくとも機械方向に延伸することで多孔化させる多孔化工程と、を含み、　ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であることを特徴とする延伸多孔性フィルムの製造方法。 [4] density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, is 20 parts by mass or less A mixing step of mixing liquid paraffin and an inorganic filler to obtain a resin composition, a forming step of forming the resin composition into a film shape, and stretching the film obtained by the forming step at least in the machine direction The melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min. It is the above, The manufacturing method of the extending | stretching porous film characterized by the above-mentioned.
　〔５〕前記多孔化工程における機械方向の延伸倍率が以下の式ＩＩにて示されることを特徴とする〔４〕に記載の延伸多孔性フィルムの製造方法：
　１．４≦Ｙ≦０．０７５Ｘ＋１．８　　　・・・（式ＩＩ）
　（式中、Ｘはポリオレフィン系樹脂１００質量部に対する流動パラフィンの配合割合（質量部）を示し、Ｙは延伸倍率（倍）を示す）。 [5] The method for producing a stretched porous film according to [4], wherein the stretching ratio in the machine direction in the above-mentioned porosifying step is represented by the following formula II:
1.4 ≦ Y ≦ 0.075X + 1.8 (Formula II)
(In the formula, X represents a blending ratio (parts by mass) of liquid paraffin to 100 parts by mass of a polyolefin resin, and Y represents a stretching ratio (fold)).
　本発明は、例えば、おむつ等の個人ケアー製品に好適に利用することができる。 The present invention can be suitably used, for example, in personal care products such as diapers.

Claims (5)

  1. 　密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、
    　前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、
    　無機充填剤と、を含有する樹脂組成物より構成され、
    　ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であり、
    　ＡＳＴＭ　Ｅ９６に準じて４０℃、相対湿度６０％の条件で測定される透湿度が１４００ｇ／ｍ２・２４ｈ以上であることを特徴とする延伸多孔性フィルム。     Density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less,
    Liquid paraffin which is 5.0 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polyolefin resin,
    A resin composition containing an inorganic filler;
    The melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min. That's it,
    A stretched porous film characterized by having a moisture permeability of 1400 g / m 2 · 24 h or more measured under the conditions of 40 ° C and a relative humidity of 60% according to ASTM E96.
  2. 　ＪＩＳ　Ｋ　７１２７に準じて、チャック間距離５０ｍｍ、引張り速度２００ｍｍ/ｍｉｎ．で機械方向に引張り、チャック間距離が５％伸びた時の機械方向の強度が０．３Ｎ／２５ｍｍ以上、２．５Ｎ／２５ｍｍ以下であることを特徴とする請求項１に記載の延伸多孔性フィルム。 According to JIS K 7127, the distance between chucks 50 mm, the tension speed 200 mm / min. The tensile porosity according to claim 1, characterized in that the strength in the machine direction when the distance between chucks is stretched by 5% by pulling in the machine direction is 0.3 N / 25 mm or more and 2.5 N / 25 mm or less. the film.
  3. 　ＪＩＳ　Ｐ　８１１７に準じて王研式試験機法で測定される通気度が３００秒／１００ｍＬ以上、２０００秒／１００ｍＬ以下であることを特徴とする請求項１または２に記載の延伸多孔性フィルム。 The stretched porous film according to claim 1 or 2, wherein the air permeability measured by the Oken type tester according to JIS P 8117 is 300 seconds / 100 mL or more and 2000 seconds / 100 mL or less.
  4. 　密度が０．９００ｇ／ｃｍ３以上、０．９４０ｇ／ｃｍ３以下であるポリオレフィン系樹脂と、前記ポリオレフィン系樹脂１００質量部に対し、５．０質量部以上、２０質量部以下である流動パラフィンと、無機充填剤と、を混合して樹脂組成物を得る混合工程と、
    　前記樹脂組成物をフィルム状に成形する成形工程と、
    　前記成形工程によって得られたフィルムを少なくとも機械方向に延伸することで多孔化させる多孔化工程と、を含み、
    　ＪＩＳ　Ｋ　７２１０に準じて１９０℃で測定される前記樹脂組成物のメルトマスフローレイトが２．０ｇ／１０ｍｉｎ．以上であることを特徴とする延伸多孔性フィルムの製造方法。     Density 0.900 g / cm 3 or more, and a polyolefin resin is 0.940 g / cm 3 or less, relative to the polyolefin resin 100 mass parts, 5.0 parts by mass or more, and the liquid paraffin 20 parts by mass or less Mixing an inorganic filler to obtain a resin composition;
    A forming step of forming the resin composition into a film shape;
    And V. a porosifying step of porosifying the film obtained by the forming step by at least stretching in the machine direction,
    The melt mass flow rate of the resin composition measured at 190 ° C. according to JIS K 7210 is 2.0 g / 10 min. It is the above, The manufacturing method of the extending | stretching porous film characterized by the above-mentioned.
  5. 　前記多孔化工程における機械方向の延伸倍率が以下の式ＩＩにて示されることを特徴とする請求項４に記載の延伸多孔性フィルムの製造方法：
    　１．４≦Ｙ≦０．０７５Ｘ＋１．８　　　・・・（式ＩＩ）
    　（式中、Ｘはポリオレフィン系樹脂１００質量部に対する流動パラフィンの配合割合（質量部）を示し、Ｙは延伸倍率（倍）を示す）。     The method for producing a stretched porous film according to claim 4, wherein the stretching ratio in the machine direction in the porosifying step is represented by the following formula II:
    1.4 ≦ Y ≦ 0.075X + 1.8 (Formula II)
    (In the formula, X represents a blending ratio (parts by mass) of liquid paraffin to 100 parts by mass of a polyolefin resin, and Y represents a stretching ratio (fold)).
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US10646414B2 (en) 2015-05-11 2020-05-12 Conopco, Inc. Personal cleansing composition
WO2023074731A1 (en) * 2021-10-29 2023-05-04 株式会社トクヤマ Stretched porous film and method for producing same

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US10646414B2 (en) 2015-05-11 2020-05-12 Conopco, Inc. Personal cleansing composition
WO2023074731A1 (en) * 2021-10-29 2023-05-04 株式会社トクヤマ Stretched porous film and method for producing same

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