JP2013108204A - Polyolefin resin nonwoven fabric for sanitary material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin resin nonwoven fabric that has excellent wettability to water without impairing mechanical strength.SOLUTION: There is provided a polyolefin resin nonwoven fabric for sanitary material that includes a polyolefin resin composition containing: a polyolefin resin modifier (A) that is obtained by copolymerizing copolymerization components that contain a polyolefin (a), an unsaturated (poly)carboxylic acid(anhydride) (b) and a 6-36C α-olefin (c) and do not contain styrene or a styrene derivative in the presence of a radical initiator (d); and a polyolefin resin (B).

Description

  The present invention relates to a polyolefin resin nonwoven fabric for sanitary materials. More specifically, the present invention relates to a polyolefin resin nonwoven fabric for sanitary materials having excellent wettability without impairing mechanical strength. Here and below, wettability means affinity for water and is evaluated by wet tension described later.

Polyolefin resin nonwoven fabrics are widely used for hygiene materials that require excellent wettability to water because they are excellent in rigidity, heat resistance, chemical resistance, and the like, and are inexpensive. However, since the polyolefin resin is hydrophobic, in order to use it in applications requiring water wettability, the wettability must be imparted by various treatments.
Conventionally, as a method of improving wettability, a method of performing corona treatment or plasma treatment on the surface of a polyolefin resin nonwoven fabric (see, for example, Patent Document 1), a method of adding thermoplastic polyethylene oxide and a surfactant to a polyolefin resin (eg, Patent Document 2) is known.

JP 2001-0405575 A JP-A-8-157650

However, the method of performing corona treatment or plasma treatment on the nonwoven fabric surface has a problem that wettability decreases with the passage of time after the treatment. In addition, in the method of adding a surfactant to a polyolefin resin, the mechanical strength (such as tensile strength; the same shall apply hereinafter) inherent in the original polyolefin resin nonwoven fabric may be impaired if an addition amount that exhibits a sufficient modification effect is added. However, there is a problem that the surfactant bleeds out from the nonwoven fabric, and improvement has been eagerly desired.
The objective of this invention is providing the polyolefin resin nonwoven fabric which has the outstanding wettability with respect to water, without impairing mechanical strength.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have reached the present invention. That is, a copolymer component containing a polyolefin (a), an unsaturated (poly) carboxylic acid (anhydride) (b) and an α-olefin (c) having 6 to 36 carbon atoms and not containing styrene or a styrene derivative is a radical. A polyolefin resin nonwoven fabric for sanitary materials comprising a polyolefin resin modifier (A) copolymerized in the presence of an initiator (d) and a polyolefin resin composition containing a polyolefin resin (B).

The polyolefin resin nonwoven fabric of the present invention has the following effects required for sanitary material applications.
(1) Excellent wettability with water without impairing the original mechanical strength.
(2) The wettability is excellent in sustainability.

[Polyolefin (a)]
The polyolefin (a) in the present invention includes one or more (co) polymers of olefins, and a copolymer of one or more olefins and one or more other monomers. A polymer is included.
Examples of the olefin include alkenes having 2 to 30 carbon atoms (hereinafter abbreviated as C) such as ethylene, propylene, 1- and 2-butene, and isobutene, and C5-30 α-olefins (1-hexene, 1-hexene, Decene, 1-dodecene, etc.); other monomers include C4-30 unsaturated monomers that are copolymerizable with olefins, such as vinyl acetate.

Specific examples of (a) include ethylene unit-containing (propylene unit-free) (co) polymers such as high, medium, and low density polyethylene, and ethylene and C4-30 unsaturated monomers [butene (1 -Butene, etc.), C5-30 α-olefin (1-hexene, 1-dodecene, etc.), vinyl acetate, etc.] [weight ratio is the moldability of the resin composition and the molecule of (a) described later] From the viewpoint of the number of double bonds therein, preferably 30/70 to 99/1, more preferably 50/50 to 95/5) and the like; propylene unit-containing (ethylene unit-free) (co) polymer such as polypropylene, Copolymer of propylene and C4-30 unsaturated monomer (same as above) [weight ratio is preferably 30 from the viewpoint of the number of double bonds in the molecule of (a) and moldability of the resin composition. / 70-99 / 1, even better 50/50 to 95/5]; ethylene / propylene copolymer [weight ratio is preferably 0.5 / 99 from the viewpoint of moldability of the resin composition and the number of double bonds in the molecule of (a)]. 5-30 / 70, more preferably 2 / 98-20 / 80]; (co) polymers of C4 or higher olefins such as polybutene.
Among these, from the viewpoint of copolymerization with an unsaturated (poly) carboxylic acid (anhydride) (b) and C6-36 α-olefin (c) described later, polyethylene, polypropylene, ethylene / propylene copolymer are preferable. Polymers, propylene / C4-30 unsaturated monomer copolymers, more preferably ethylene / propylene copolymers.
(A) is a compound in the molecular chain and / or at the molecular terminal from the viewpoint of copolymerization with an unsaturated (poly) carboxylic acid (anhydride) (b) described later and an α-olefin (c) of C6-36. It preferably has a double bond.
The number of double bonds per 1,000 carbon atoms in (a) is preferably from the viewpoint of the copolymerizability between (a), (b) and (c) and the productivity of (A). The number is 20, more preferably 0.3 to 18, and particularly preferably 0.5 to 15.
Here, the number of double bonds can be determined from the spectrum of (a) ¹ H-NMR (nuclear magnetic resonance) spectroscopy. That is, the peak in the spectrum is assigned, and from the integrated value derived from the double bond at 4.5 to 6 ppm of (a) and the integrated value derived from (a), the number of double bonds in (a) and (a) Is calculated, and the number of double bonds in the molecular end and / or molecular chain per 1,000 carbon atoms in (a) is calculated. The number of double bonds in the examples described later followed this method.

  Polyolefin (a) can be produced by polymerization methods (for example, those described in JP-A-59-206409) and degradation methods (thermal, chemical and mechanical degradation methods, etc.). Examples of the degradation method (hereinafter also referred to as the thermal degradation method) include those described in Japanese Patent Publication No. 43-9368, Japanese Patent Publication No. 44-29742, and Japanese Patent Publication No. 6-70094].

  The polymerization method includes a method of (co) polymerizing one or more of the olefins, and a method of copolymerizing one or more of the olefins and one or more of the other monomers. It is.

  In the degradation method, the high molecular weight [number average molecular weight [hereinafter abbreviated as Mn] obtained by the polymerization method. The measurement is performed by a gel permeation chromatography (GPC) method described later], but is copolymerizable with an unsaturated (poly) carboxylic acid (anhydride) and an α-olefin having 6 to 36 carbon atoms described later and (a). From the viewpoint of productivity, a method of thermally, chemically or mechanically degrading a polyolefin (a0) of preferably 30,000 to 400,000, more preferably 50,000 to 200,000] is included.

The measurement conditions of Mn by GPC in the present invention are as follows.
Equipment: High temperature gel permeation chromatography
["Alliance GPC V2000",
Waters Co., Ltd.]
Solvent: Orthodichlorobenzene Reference substance: Polystyrene Sample concentration: 3 mg / ml
Column stationary phase: PLgel 10 μm MIXED-B
Two [Polymer Laboratories Co., Ltd.] connected in series Column temperature: 135 ° C

In the thermal degradation method, the high molecular weight polyolefin (a0) is subjected to thermal degradation in the presence of nitrogen (1) in the absence of an organic peroxide, usually at 300 to 450 ° C. for 0.5 to 10 hours. And (2) a method of thermally degrading usually at 180 to 300 ° C. for 0.5 to 10 hours in the presence of an organic peroxide.
Among these, the polyolefin (a) obtained from the viewpoint of copolymerizability with (b) and (c) is preferably one having a larger number of double bonds in the molecular chain and / or molecular terminal. This is the easy method (1).

  Among these production methods (a), those having a larger number of double bonds in the molecular chain and / or at the molecular end are easily obtained, and the copolymerization of (a), (b) and (c) From the viewpoint of ease, a degradation method is preferable, and a thermal degradation method is more preferable.

  Mn of (a) is preferably 800 to 50,000, more preferably 1,500 to 30,000, from the viewpoint of mechanical strength of the polyolefin resin nonwoven fabric for sanitary materials described later and productivity of (A).

[Unsaturated (poly) carboxylic acid (anhydride) (b)]
The unsaturated (poly) carboxylic acid (anhydride) (b) in the present invention is a C3-30 (poly) carboxylic acid (anhydride) having one polymerizable unsaturated group. In the present invention, the unsaturated (poly) carboxylic acid (anhydride) means an unsaturated monocarboxylic acid, an unsaturated polycarboxylic acid and / or an unsaturated polycarboxylic anhydride.
Among these (b), as the unsaturated monocarboxylic acid, aliphatic (C3-24, for example, acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, isocrotonic acid), alicyclic ring-containing (C6-24, For example, cyclohexene carboxylic acid); unsaturated poly (2-3 or more) carboxylic acid (anhydride) include unsaturated dicarboxylic acid (anhydride) [aliphatic dicarboxylic acid (anhydride) (C4-24, eg malee Acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and anhydrides thereof), alicyclic dicarboxylic acids (anhydrides) (C8-24, such as cyclohexene dicarboxylic acid, cycloheptene dicarboxylic acid, bicycloheptide) Tendenedicarboxylic acid, methyltetrahydrophthalic acid, and their anhydrides) and the like. (B) may be used alone or in combination of two.
Of these, unsaturated dicarboxylic acid (anhydride) is preferable from the viewpoint of copolymerizability with C6-36 α-olefin (c) described later, more preferably unsaturated dicarboxylic acid anhydride, and particularly preferable. Maleic anhydride.

[C6-36 α-olefin (c)]
The α-olefin (c) in the present invention includes C6 to 36, preferably C8 to 30 linear α-olefins and branched α-olefins. When the C of (c) is less than 6, the mechanical strength of the polyolefin resin nonwoven fabric is lowered, and when it exceeds 36, the wettability of the polyolefin resin nonwoven fabric is deteriorated.
Examples of the linear α-olefin in (c) include 1-hexene, 1-octene, 1-nonene, 1-decene, and a mixture of two or more thereof.
Examples of the α-olefin having a branched chain include propylene trimer, propylene tetramer, and a mixture of two or more thereof.
Of these, linear α-olefins are preferred from the viewpoint of copolymerizability with (a) and (b), and 1-decene is more preferred.

  The content of each component based on the total weight of (a), (b), and (c) is preferably 30 to 98% from the viewpoint of (A) productivity and improved wettability of the polyolefin resin nonwoven fabric. More preferably, 40 to 90%; (b) is preferably 0.03 to 40%, more preferably 0.5 to 35% from the viewpoint of improving the wettability of the polyolefin resin nonwoven fabric and the productivity of (A); c) is preferably 0.6 to 65%, more preferably 1 to 50% from the viewpoint of improving the mechanical strength and wettability of the polyolefin resin nonwoven fabric.

[Radical initiator (d)]
(A), (b) and (c) in the present invention are copolymerized in the presence of the radical initiator (d).
Examples of (d) include azo compounds (azobisisobutyronitrile, azobisisovaleronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobiscyclohexane-1-carbohydrate. Nitrile, 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis (2,4,4-trimethylpentane), 2,2'-azobis (N-cyclohexyl-2- Methylpropionamide)), peroxides (monofunctional (having one peroxide group in the molecule) (benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, dicumyl peroxide, etc.) and many Functional (having two or more peroxide groups in the molecule) [2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, -t- butyl peroxyhexahydroterephthalate, diallyl peroxydicarbonate and the like]], and the like.

  Of these, from the viewpoint of the copolymerizability of (a), (b) and (c), preferred are peroxides, more preferred are monofunctional peroxides, particularly preferred is di-t-butyl peroxide, Lauroyl peroxide and dicumyl peroxide.

  The amount of (d) used is preferably 0.05 to 10%, more preferably 0.2 based on the total weight of (a), (b) and (c) from the viewpoint of reactivity and side reaction suppression. -5%, particularly preferably 0.5-3%.

[Polyolefin resin modifier (A)]
In the present invention, the polyolefin resin modifier (A) is a polyolefin (a), an unsaturated (poly) carboxylic acid (anhydride) (b), and an α- of C6-36 in the presence of a radical initiator (d). A copolymer component containing olefin (c) and not containing styrene or a styrene derivative is copolymerized.

The copolymer component that constitutes the polyolefin resin modifier (A) does not contain styrene or styrene derivatives. When styrene or a styrene derivative is not included in the copolymer component, the productivity of (A) is further improved.
The styrene derivatives include those having C9 to 15 such as α-methylstyrene, p-methoxystyrene, m-butylstyrene and the like.

The specific production method (A) includes the following methods [1] and [2].
[1] (a), (b) and (c) are mixed with a suitable organic solvent [C3-18, such as hydrocarbon (hexane, heptane, octane, dodecane, benzene, toluene, xylene, etc.), halogenated hydrocarbon (di- -, Tri- and tetrachloroethane, dichlorobutane, etc.), ketones (acetone, methyl ethyl ketone, di-t-butyl ketone, etc.), ethers (ethyl-n-propyl ether, di-n-butyl ether, di-t-butyl ether, dioxane, etc.) )], Or (d) [or a solution in which (d) is dissolved in an appropriate organic solvent (the same as above)] and, if necessary, a chain transfer agent (t) described below are added. Method of heating and stirring (solution method);
[2] A method (melting method) in which (a), (b), (c) and (d), and (t) as necessary are mixed in advance and kneaded using an extruder, a Banbury mixer, a kneader or the like.

  The reaction temperature in the solution method may be a temperature at which (a) is dissolved in an organic solvent, and is preferably 50 from the viewpoint of productivity of (A) and reaction control of (a), (b), and (c). It is -220 degreeC, More preferably, it is 110-210 degreeC, Most preferably, it is 120-180 degreeC.

  The reaction temperature in the melting method may be a temperature at which (a) melts, and is preferably 120 from the viewpoint of the copolymerizability of (a), (b) and (c) and the decomposition temperature of the reaction product. It is -260 degreeC, More preferably, it is 130-240 degreeC.

Examples of the chain transfer agent (t) include alcohols (C1-24, such as methanol, ethanol, 1-propanol, 2-butanol, allyl alcohol); thiols (C1-24, such as ethylthiol, propylthiol, 1- and 2). Aldehyde (C2-18, such as 2-methyl-2-propylaldehyde, 1- and 2-butyraldehyde, 1-pentylaldehyde); phenol (C6-36, such as phenol, o -, M- and p-cresol); amines (C3-24, such as diethylmethylamine, triethylamine, diphenylamine); disulfides (C2-24, such as diethyldisulfide, di-1-propyldisulfide) and the like.
The amount of (t) used is usually 30% or less based on the total weight of (a), (b) and (c), preferably from the viewpoint of the productivity of (A) and the mechanical strength of the polyolefin resin nonwoven fabric described later. Is 0.1 to 20%.

  Mn of the polyolefin resin modifier (A) is preferably 1,500 to 70,000, more preferably 2,000 to 60, from the viewpoint of mechanical strength of the polyolefin resin nonwoven fabric described later and moldability of the resin composition. 000, particularly preferably 2,500 to 50,000.

The acid value of (A) is preferably 0.5 to 200 mg KOH / g (only numerical values are shown below), more preferably 1 to 180, particularly preferably from the viewpoint of the wettability of the polyolefin resin nonwoven fabric and the productivity of (A). Is 5 to 160. The acid value here is a value obtained by measurement according to the following procedures (i) to (iii) according to JIS K0070.
(I) 1 g of (A) is dissolved in 100 g of xylene adjusted to 100 ° C.
(Ii) Titration is performed with a 0.1 mol / L potassium hydroxide ethanol solution [trade name “0.1 mol / L ethanolic potassium hydroxide solution”, manufactured by Wako Pure Chemical Industries, Ltd.] using phenolphthalein as an indicator.
(Iii) The amount of potassium hydroxide required for titration is converted to mg, and the acid value (unit: mgKOH / g) is calculated.

  The modifier (A) in the present invention is used as a modifier for the polyolefin resin (B) described later.

[Polyolefin resin (B)]
The polyolefin resin (B) in the present invention is obtained by the polymerization method exemplified as the production method of the above (a), or a high molecular weight (preferably Mn 30,000 to 400,000) polyolefin degradation (thermally, Chemical and mechanical degradation), and (B) includes the above-mentioned ethylene unit-containing (propylene unit-free) (co) polymer, propylene unit-containing (ethylene-unit-free) ) (Co) polymers, ethylene / propylene copolymers and (co) polymers of C4 or higher olefins.

  As a combination of (A) and (B) in the present invention, there are cases where the structural unit of (B) and the structural unit of the polyolefin (a) constituting (A) are the same or similar (A) and (B ) From the viewpoint of compatibility. For example, when (B) is a propylene unit-containing (ethylene unit-free) (co) polymer, (a) constituting (A) is also a propylene unit-containing (ethylene unit-free) (co) polymer. Some cases are preferred.

  Mn of (B) is preferably 10,000 to 500,000, more preferably 20,000 to 400,000 from the viewpoint of mechanical strength of the polyolefin resin nonwoven fabric and compatibility with (A).

[Polyolefin resin composition]
The polyolefin resin composition in this invention contains the said modifier (A) and polyolefin resin (B).

If necessary, the polyolefin resin composition may further contain various additives (C) as long as the effects of the present invention are not impaired.
(C) includes colorant (C1), flame retardant (C2), filler (C3), lubricant (C4), antistatic agent (C5), antioxidant (C6) and ultraviolet absorber (C7). 1 type (s) or 2 or more types selected from the group which consists of.

Examples of the colorant (C1) include pigments and dyes.
Examples of pigments include inorganic pigments (alumina white, graphite, etc.), organic pigments (azo lakes, etc.), and examples of dyes include azos, anthraquinones, and the like.

  Examples of the flame retardant (C2) include organic flame retardants [nitrogen-containing compounds [salts such as urea compounds and guanidine compounds], sulfur-containing compounds [sulfuric esters, sulfamic acids and their salts, esters, amides, etc.], silicon-containing compounds Compound [polyorganosiloxane etc.], phosphorus-containing [phosphate ester etc.]]; inorganic flame retardant [antimony trioxide, magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, etc.] and the like.

  Fillers (C3) include carbonates (magnesium carbonate, calcium carbonate, etc.), sulfates (aluminum sulfate, etc.), sulfites (calcium sulfite, etc.), metal sulfides (molybdenum disulfide, etc.), silicates (aluminum silicate) Etc.), diatomaceous earth, silica powder, talc, silica, zeolite, and mixtures thereof.

  Examples of the lubricant (C4) include waxes (such as carnauba wax), higher fatty acids (such as stearic acid), higher alcohols (such as stearyl alcohol), and higher fatty acid amides (such as stearic acid amide).

  Examples of the antistatic agent (C5) include low molecular weight antistatic agents (nonionic, cationic, anionic and amphoteric interfaces described in US Pat. Nos. 3,929,678 and 4,331,447). Activators and the like), and polymer type permanent antistatic agents (such as block copolymers of polyolefin and polyoxyalkylene glycol, block copolymers of polyamide and polyoxyalkylene glycol, etc.).

  Antioxidants (C6) include hindered phenol compounds [pt-amylphenol-formaldehyde resin, nordihydroguaiaretic acid (NDGA), 2,6-di-tert-butyl-4-methylphenol (BHT). ), 2-t-butyl-4-methylphenol (BHA), 6-t-butyl-2,4, -methylphenol (24M6B), 2,6-di-t-butylphenol (26B) and the like]; Compound [N, N′-diphenylthiourea, dimyristylthiodipropionate, etc.]; Phosphorus compound [2-t-butyl-α- (3-t-butyl-4-hydroxyphenyl) -p-cumenylbis (p- Nonylphenyl) phosphite, dioctadecyl-4-hydroxy-3,5-di-t-butylbenzylphosphonate, etc.].

  Examples of the ultraviolet absorber (C7) include salicylate compounds [phenyl salicylate and the like]; benzophenone compounds [2,4-dihydroxyzenzophenone and the like]; benzotriazole compounds [2- (2′-hydroxy-5′-methylphenyl). ) -Benzotriazole and the like].

The total content of (C) in the polyolefin resin composition is usually 20% or less based on the total weight of the composition, preferably 0.05 to 10 from the viewpoint of functional expression of each (C) and an industrial viewpoint. %, More preferably 0.1 to 5%.
The amount of each additive used based on the total weight of the composition is as follows: (C1) is usually 5% or less, preferably 0.1 to 3%; (C2) is usually 8% or less, preferably 1 to 3%; (C3) is usually 5% or less, preferably 0.1 to 1%; (C4) is usually 8% or less, preferably 1 to 5%; (C5) is usually 25% or less, preferably 1 to 20%; (C6) is usually 2% or less, preferably 0.05 to 0.5%; (C7) is usually 2% or less, preferably 0.05 to 0.5%.

  When the additive is the same and overlaps between (C1) to (C7) above, it is not used regardless of the effect as the other additive in the amount that each additive exhibits the corresponding additive effect, Considering that the effects as other additives can be obtained at the same time, the amount used is adjusted according to the purpose of use.

As a method for producing a polyolefin resin composition in the present invention,
(1) A method (collective method) in which (A), (B) and, if necessary, (C) are mixed at once to obtain a polyolefin resin composition;
(2) A masterbatch polyolefin resin composition containing a high concentration of (A) is prepared by mixing a part of (B), the total amount of (A), and if necessary, a part or all of (C). Then, a method (masterbatch method) is included in which the remaining (B) and, if necessary, the remaining (C) are added and mixed to obtain a polyolefin resin composition.
The method (2) is preferable from the viewpoint of the mixing efficiency of (A).

  The weight ratio of (A) and (B) in the polyolefin resin composition in the present invention is preferably 1/99 to 40/60, more preferably 5 from the viewpoint of wettability and mechanical strength of the polyolefin resin nonwoven fabric described later. / 95 to 35/65, particularly preferably 10/90 to 30/70.

As a specific mixing method in the manufacturing method of the resin composition,
(I) Each component to be mixed is, for example, a powder mixer [“Henschel mixer” [trade name “Henschel mixer FM150L / B”, manufactured by Mitsui Mining Co., Ltd.], “Nauta mixer” [trade name “Nauta mixer DBX3000RX”. , Manufactured by Hosokawa Micron Co., Ltd.], “Banbury Mixer” [trade name “MIXTRON BB-16MIXER”, manufactured by Kobe Steel, Ltd.], etc.], and then mixed with a melt-kneader [batch kneader, continuous kneader (single A kneading machine at 120 to 220 ° C. for 0.5 to 30 minutes;
(Ii) A method of directly kneading the components to be mixed under the same conditions using the same melt-kneading apparatus as described above without mixing powders in advance.
Among these methods, the method (i) is preferable from the viewpoint of mixing efficiency.

[Polyolefin resin nonwoven fabric for sanitary materials]
The polyolefin resin nonwoven fabric of the present invention is a nonwoven fabric made of the polyolefin resin composition.

  As a method for producing the polyolefin resin nonwoven fabric of the present invention, using the resin composition, for example, a direct method such as a spunbond method, a melt blow method, a flash spinning method or the like, a card web is obtained from short fibers, and this is hydroentangled. There is a method of manufacturing by a fiber fixing method such as embossing or needle punching, and the manufacturing method of these nonwoven fabrics is not particularly limited.

  The shape of the fiber cross section of the nonwoven fabric is not particularly limited, and there are no problems even if it is circular, irregular, or hollow, and various types can be obtained by appropriately selecting the shape of the spinneret. It can be a cross-sectional shape.

The manufacturing method of the said nonwoven fabric is specifically as follows.
(I) Spunbond method:
A polyolefin resin composition is heated and melted and discharged from a spinneret, and the discharged spun yarn is cooled using various cooling devices such as horizontal spraying or annular spraying, and then taken up (for example, air soccer etc.) Using a suction device, a roller, etc.), and then opening the yarn group discharged from the suction device, and then opening and depositing it on a moving deposition device such as a conveyor consisting of a screen. Get fiber. Next, the lump-like fibers formed on the moving deposition apparatus are partially subjected to thermocompression bonding using a partial thermocompression bonding apparatus such as a heated embossing apparatus or ultrasonic fusion apparatus to obtain a nonwoven fabric.
(Ii) Melt blow method:
Conveyor net that moves the fine fiber stream that is made into fine fibers by blowing high-temperature high-speed gas at the same temperature as the spinning temperature from the slit-shaped gas outlet installed adjacent to the spinning hole at the same time as melt spinning from the spinning hole Collect on top to obtain a nonwoven fabric.
Of these polyolefin resin nonwoven fabric production methods, the spunbond method and the melt blow method are preferable from the viewpoint of productivity, and the spunbond method is more preferable.

The wettability of the polyolefin resin nonwoven fabric of the present invention to water can be evaluated by the wet tension of a film obtained by melting and molding the nonwoven fabric. The wet tension of the film is preferably 33 to 50 mN / m, more preferably 34 to 45 mN / m from the viewpoint of application to sanitary materials where high wettability is required and the mechanical strength of the nonwoven fabric.
Moreover, the wettability with respect to the water with the shape of the nonwoven fabric maintained can be evaluated by, for example, the water retention rate of the nonwoven fabric described later. The water retention rate is preferably 70 to 300%, more preferably 80 to 200%, and particularly preferably 100 to 150% from the same viewpoint as described above.

  Examples of the sanitary material in the present invention include paper diapers, masks, gauze, bandages and the like that are particularly required to have excellent wettability with water and excellent sustainability.

  EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” means “part by weight” and “%” other than mol% means “% by weight”.

[Production of polyolefin (a)]
Production Example 1
Polyolefin (a0-1) comprising 98 mol% propylene and 2 mol% ethylene as a structural unit (trade name “Sun Allomer PZA20A”, manufactured by Sun Allomer Co., polymerization method, per 1,000 carbon atoms) 0 double bonds, Mn 100,000, and so on. 100 parts were charged in a nitrogen atmosphere, heated and melted with a mantle heater while nitrogen was passed through the gas phase, and subjected to heat degradation at 360 ° C. for 70 minutes with stirring to obtain polyolefin (a-1). . In (a-1), the number of double bonds per 1,000 carbon atoms was 7.2, and Mn was 3,000.

Production Example 2
In Production Example 1, a polyolefin (a-2) was obtained in the same manner as in Production Example 1 except that the heat degradation time was changed from 70 minutes to 100 minutes. In (a-2), the number of double bonds per 1,000 carbon atoms was 18, and Mn was 1,200.

Production Example 3
In Production Example 1, a polyolefin (a-3) was obtained in the same manner as in Production Example 1 except that the heat degradation time was changed from 70 minutes to 20 minutes. In (a-3), the number of double bonds per 1,000 carbon atoms was 0.3, and Mn was 45,000.

Production Example 4
In Production Example 1, instead of 100 parts of polyolefin (a0-1), polyolefin (a0-2) having a structural unit of 80 mol% of propylene and 20 mol% of 1-butene [trade name “Tafmer XM-5080, the same shall apply hereinafter. In the same manner as in Production Example 1 except that 100 parts of Mn 90,000] manufactured by Mitsui Chemicals, Inc. were used, polyolefin (a-4) was obtained. In (a-4), the number of double bonds per 1,000 carbon atoms was 7.2, and Mn was 3,000.

[Production of polyolefin resin modifier (A)]
Production Example 5
A reaction vessel was charged with 100 parts of (a-1), 24 parts of maleic anhydride (b-1), 18.5 parts of 1-decene (c-1), and 100 parts of xylene. The mixture was heated to 130 ° C. and dissolved uniformly. A solution prepared by dissolving 0.5 parts of dicumyl peroxide [trade name “Park Mill D”, manufactured by NOF Corporation] in 10 parts of xylene was added dropwise over 10 minutes, and stirring was continued for 3 hours under reflux of xylene. It was. Thereafter, xylene and unreacted maleic anhydride were distilled off under reduced pressure (1.5 kPa, the same shall apply hereinafter) to obtain a polyolefin resin modifier (A-1). (A-1) had an acid value of 95 and Mn of 5,000.

Production Example 6
In Production Example 5, instead of (a-1) 100 parts, (b-1) 24 parts, (c-1) 18.5 parts, (a-2) 100 parts, (b-1) 100 parts, (C-1) Except having used 85.7 parts, it carried out similarly to manufacture example 5, and obtained the polyolefin resin modifier (A-2). (A-2) had an acid value of 200 and Mn of 4,000.

Production Example 7
In Production Example 5, instead of (a-1) 100 parts, (b-1) 24 parts, (c-1) 18.5 parts, (a-3) 100 parts, (b-1) 1 part, (C-1) Except having used 2 parts, it carried out similarly to manufacture example 5, and obtained the polyolefin resin modifier (A-3). (A-3) had an acid value of 6 and Mn of 45,000.

Production Example 8
In Production Example 5, a polyolefin resin modifier (A-4) was obtained in the same manner as in Production Example 5 except that 100 parts of (a-4) was used instead of 100 parts of (a-1). . (A-4) had an acid value of 95 and Mn of 5,000.

Production Example 9
In Production Example 5, in place of 18.5 parts of (c-1), except that 3.8 parts of 1-hexene (c-2) was used, a polyolefin resin modifier ( A-5) was obtained. (A-5) had an acid value of 108 and Mn of 4,800.

Production Example 10
In Production Example 5, instead of 24 parts of (b-1) and 18.5 parts of (c-1), 33 parts of (b-1), 1-hexatriacontene (C36 α-olefin) (c-3) ) A polyolefin resin modifier (A-6) was obtained in the same manner as in Production Example 5 except that 200 parts were used. (A-6) had an acid value of 57 and Mn of 7,000.

Production Example 11
In Production Example 5, instead of 24 parts of (b-1) and 18.5 parts of (c-1), acrylic acid (b-2) [trade name “acrylic acid”, manufactured by Nippon Shokubai Co., Ltd.] 6 parts, (c-1) 18.5 parts, and 1-octadecene [trade name “Linearene 18”, Idemitsu Kosan Co., Ltd., C18 α-olefin] (c-4) 2.7 parts Except having used this, it carried out similarly to manufacture example 5, and obtained the polyolefin resin modifier (A-7). (A-7) had an acid value of 95 and Mn of 5,000.

Production Example 12
In Production Example 5, instead of (a-1) 100 parts, (b-1) 24 parts, (c-1) 18.5 parts, (a0-1) 100 parts, maleic acid (b-3) [ A polyolefin resin modifier (A-8) was prepared in the same manner as in Production Example 5 except that 5 parts of a trade name “maleic acid” manufactured by Wako Pure Chemical Industries, Ltd. and 3 parts of (c-1) were used. ) (A-8) had an acid value of 45 and Mn of 105,000.

Production Example 13
In Production Example 5, instead of (a-1) 100 parts, (b-1) 24 parts, (c-1) 18.5 parts, (a-1) 100 parts, (b-1) 150 parts, (C-1) Except having used 150 parts, it carried out similarly to manufacture example 5, and obtained the polyolefin resin modifier (A-9). (A-9) had an acid value of 214 and Mn of 6,000.

Comparative production example 1
In Production Example 5, instead of 24 parts (b-1) and 18.5 parts (c-1), 11 parts (b-1) were used, except that (c-1) was not used. In the same manner as in Production Example 5, a polyolefin resin modifier (Ratio A-1) was obtained. (Ratio A-1) had an acid value of 50 and Mn of 3,500.

Comparative production example 2
In Production Example 5, instead of using 24 parts of (b-1) and 18.5 parts of (c-1), 27 parts of (b-1) and 7 parts of 1-butene (ratio c-1) were used. Was carried out in the same manner as in Production Example 5 to obtain a polyolefin resin modifier (Ratio A-2). (Ratio A-2) had an acid value of 57 and Mn of 3,500.

Comparative production example 3
In Production Example 5, in the same manner as Production Example 5 except that 120 parts of 1-pentacontene (C50 α-olefin) (ratio c-2) was used instead of 18.5 parts of (c-1). And a polyolefin resin modifier (Ratio A-3) was obtained. (Ratio A-3) had an acid value of 57 and Mn of 3,000.

Examples 1-13, Comparative Examples 1-8
(A-1) to (A-7), (Ratio A-1) to (Ratio A-3), a commercially available low molecular weight modifier (Ratio A-4) [aliphatic ester nonionic surfactant, Trade name “Chemistat 1100”, manufactured by Sanyo Chemical Industries, Ltd., commercially available polypropylene (B-1) [trade name “Sun Allomer PL500A”, manufactured by Sun Allomer, Mn 300,000], commercially available polyethylene (B-2) ) [Trade name “Novatech HJ490”, manufactured by Nippon Polyethylene Co., Ltd., Mn 300,000] and commercially available ethylene / propylene copolymer (B-3) [trade name “Sun Aroma PB222A”, manufactured by Sun Allomer Co., Mn 350, 000] in accordance with the blending composition (parts) in Table 1 for 3 minutes with a Henschel mixer, respectively, and then at 180 ° C., 100 rpm, with a vented twin screw extruder To obtain a polyolefin resin composition was melt-kneaded at 5 minutes. The polyolefin resin nonwoven fabric obtained by the spunbond nonwoven fabric manufacturing method described later for each polyolefin resin composition was evaluated according to the evaluation method described later. The results are shown in Table 1.

[Spunbond manufacturing method]
Each polyolefin resin composition was melt-spun from a spinning nozzle heated to 230 ° C. and adjusted in temperature, and cooled at 35 ° C. and 65% R.D. H. After cooling by blowing the cooling air, the yarn was pulled and stretched at a spinning speed of 4,500 m / min with a yarn pulling air jet device, and then the yarn group discharged from the suction device was opened. To obtain massive fibers. Next, a nonwoven fabric having a fiber diameter of 2.5 dtex and a basis weight of 40 g / m ² is obtained by partially thermocompressing the lump-like fibers formed on the moving deposition apparatus using an embossing apparatus heated to 150 ° C. Got.

<Evaluation method>
1. Tensile strength [Unit: (N / 50mm) / (g / m ² )]
A nonwoven fabric cut to a width of 50 mm and a longitudinal measurement length of 200 mm was measured according to JIS L-1906 5.3.1 (2000).

2. Wettability (Unit: mN / m)
Each nonwoven fabric was melted and pressed under conditions of 180 ° C. and 5.0 MPa using a press machine [model number “TABLE TYPE PRESS PRESS SA-302”, manufactured by Tester Sangyo Co., Ltd.] to form a film. The wetting tension of the film was measured according to JIS K6768. It shows that wettability is so favorable that wetting tension is large.
3. Persistence of wettability (unit: mN / m)
Each non-woven fabric was allowed to stand for 30 days in a circulating air temperature oven [trade name “DN410H”, manufactured by Yamato Scientific Co., Ltd.] adjusted to 50 ° C. for 10 minutes, and then washed with a 50 ° C. circulating air dryer. Dried. Each of the non-woven fabrics is treated as described in The wetting tension was measured in the same manner as above.

4). Non-woven fabric water retention (unit:%)
The weight (W0) of each non-woven fabric test piece (vertical 5 cm × horizontal 5 cm) that is allowed to stand for 5 hours in an atmosphere of 25 ° C. and 65% humidity is measured. Next, after immersing the test piece in water at a temperature of 25 ° C. for 1 hour, pulling it up from the water and suspending it for 10 minutes in an atmosphere at a temperature of 25 ° C. and a humidity of 65%, then measuring the weight (W1) of the test piece, The water retention rate was calculated from the formula.

Water retention rate (%) = (W1-W0) × 100 / W0

5. Sustainability of water retention rate of nonwoven fabric (unit:%)
4. above. Each non-woven fabric test piece after the evaluation was immersed in water at 40 ° C. for 1 hour, and then dried with a circulating dryer at 50 ° C. This procedure was repeated a further 4 times for a total of 5 times. Each non-woven fabric test piece after drying is subjected to the above 4. Similarly, the water retention rate of the nonwoven fabric was calculated.

  From the results of Table 1, it can be seen that the polyolefin resin nonwoven fabric for sanitary materials of the present invention has excellent mechanical strength and water wettability as compared with the comparative one, and is excellent in its sustainability.

The polyolefin resin nonwoven fabric for sanitary materials of the present invention is excellent in imparting wettability to water without lowering the mechanical strength of the nonwoven fabric, and is also excellent in sustainability of wettability, so that a disposable diaper, mask, filter, It can be applied to hygiene materials such as gauze and bandages and is extremely useful.

Claims (8)

A copolymerization component containing a polyolefin (a), an unsaturated (poly) carboxylic acid (anhydride) (b) and an α-olefin (c) having 6 to 36 carbon atoms and not containing styrene or a styrene derivative is a radical initiator. A polyolefin resin nonwoven fabric for sanitary materials, comprising a polyolefin resin modifier (A) obtained by copolymerization in the presence of (d) and a polyolefin resin composition containing the polyolefin resin (B). The nonwoven fabric according to claim 1, wherein (b) is an unsaturated dicarboxylic acid (anhydride). The nonwoven fabric according to claim 1 or 2, wherein (a) has 0.1 to 20 unsaturated bonds per 1,000 carbon atoms in the molecular chain and / or at the molecular end. The nonwoven fabric according to any one of claims 1 to 3, wherein (a) is a thermal degradation product of a polyolefin having a number average molecular weight of 30,000 to 400,000. The proportions based on the total weight of (a), (b) and (c) are: (a) 30-98%, (b) 0.03-40%, (c) 0.6-65% The nonwoven fabric according to any one of claims 1 to 4. The nonwoven fabric according to any one of claims 1 to 5, wherein a weight ratio of (A) to (B) is from 1/99 to 40/60. The nonwoven fabric according to any one of claims 1 to 6, wherein a wetting tension of a film formed by melting and forming the nonwoven fabric is 33 to 50 mN / m. The sanitary material is at least one selected from the group consisting of a paper diaper, a mask, a filter, a gauze, and a bandage, The nonwoven fabric according to any one of claims 1 to 7.