JPH0253950A - Production of hydrophilic non woven fabric - Google Patents

Abstract

PURPOSE:To obtain the subject non woven fabric excellent in accumulating property, bulkiness and interlocking property without reducing discharging properties by adding a hydrophilic compound such as a composition composed of a phosphoric ester and a polyethylene oxide to a molten hydrophobic polymer and spinning the mixture with a high temperature and high pressure gasflow. CONSTITUTION:During processes before spinning a molten hydrophobic polymer, a composition composed of a phosphoric ester or higher alcohol ethylene oxide addition phosphoric ester, a polyethylene oxide or polyethylene oxide fatty ester and one or more hydrophilic compound selected from a fusible polyvinyl alcohol, vinyl alcohol copolymer, higher alcohol, olefinic unsaturated (di) carboxylic acid copolymer, etc., are added thereto. The resultant mixture is discharged using a high temperature and high pressure gasflow and formed into a fiber flow, thus obtaining the objective hydrophilic non woven fabric composed of fiber web.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the production of a hydrophilic nonwoven fabric with a homogeneous fiber distribution by a melt blown method.

[Conventional technology]

Conventionally, there have been many proposals for producing a random web made of ultrafine fibers by spinning using a melt blown method. For example, in the method of manufacturing a melt-blown nonwoven fabric mat, conditions such as the polymer resin flow rate, polymer apparent viscosity, processing temperature, and gas flow rate are specified. , the heated nozzle is about 287°C to about 482°C, about 2.0°C from the outlet.
JP-A-50-46972 discloses that a thermally inert gas at a temperature of about 287 to about 482° C. is ejected into fibers at a gas flow rate of 5 to about 100 bonds/min/square inch of outlet area.
In addition, JP-A No. 60-9056 discloses that a nonwoven fabric made of ultrafine polypropylene fibers spun by the melt-blown method is given a nonionic activator of polyoxyethylene alkyl ether type to make a nonwoven fabric with liquid absorbing and liquid retaining properties. Proposed in the gazette. In addition, in order to impart hydrophilicity to the olefin polymer, a blend of nosy and/or triglyceride, alkoxylated alkylphenol, and polyoxyalkylene fatty acid ester is added to the olefin polymer and spun to produce wettable fibers or fibers. JP-A-60-194113 proposes a filament.

[Problems that the invention attempts to solve]

Conventionally, fibers obtained by spinning using the melt-blown method have the advantage that ultrafine fibers that cannot be obtained by ordinary spinning methods can be obtained in the form of nonwoven fabrics.

However, in this spinning method, the melted and discharged polymer is used to form a fiber stream using a jet gas flow, so the polymer used has a low melt viscosity, or the spinning conditions that lower the melt viscosity are rarely used. do.

Therefore, the tensile strength and abrasion strength of the M6 fibers or nonwoven fabric obtained were lower than those of ordinary fibers or nonwoven fabrics made of ultrafine fibers obtained from multicomponent fibers.

Moreover, in order to obtain hydrophilic fibers or hydrophilic nonwoven fabrics with good sustainability using hydrophobic polymers with good melt spinnability, complicated processing steps must be added.

Furthermore, wettable fibers obtained by adding a polyethylene oxide derivative and a mixed glyceride as an antifoggant to a polyolefin have good hydrophilicity, but the plasticizing effect becomes large and it is difficult to obtain a bulky nonwoven fabric.

The present invention is directed to producing a hydrophilic nonwoven fabric that has good spinnability by the melt-prone method, has improved strength, is bulky, and is hydrophilic.

[Means to solve the problem]

In the present invention, when producing a fibrous web by spinning a hydrophobic polymer melt with a high-temperature, high-pressure gas flow to form a fiber stream,
In the process of spinning the hydrophobic polymer melt,
(1) Composition of phosphoric ester or higher alcohol ethylene oxide-added phosphoric ester and polyethylene oxide or polyethylene oxide fatty acid ester, (2-melt polyvinyl alcohol or vinyl alcohol copolymer, 8) Higher alcohol, olefin unsaturated This is a method for producing a hydrophilic nonwoven fabric, characterized by adding at least one hydrophilic compound selected from the group of (di)carboxylic acid copolymers.

Furthermore, in the process of spinning the hydrophobic polymer, a hydrophilic compound different from the above-mentioned additives is added, and the spinning is performed with an apparent melt viscosity of 500 voids or less. This is a method for producing a hydrophilic nonwoven fabric.

The present invention produces a hydrophilized Orihime web from a thermoplastic hydrophobic polymer. That is, examples of thermoplastic hydrophobic polymers include polyethylene, ethylene polymers such as ethylene/propylene copolymers, ethylene/butylene copolymers, ethylene/octene copolymers, polypropylene or propylene copolymers, and polybutylene. Polyolefins such as 6-nylon, 66-nylon, 6
・66-copolymerized polyamide, 610-nylon, 11-
Polyamides or copolyamides such as nylon and 12-nylon, polyesters such as polyethylene terephthalate, ethylene terephthalate copolymers, and polybutylene terephthalate, aliphatic polycarbonates, polyurethane elastomers, polyester elastomers
At least one polymer selected from polyamide elastomer, polyvinyl chloride or vinyl chloride copolymer, wholly aromatic polyester, polyphenylene sulfide, etc. The apparent viscosity of the polymer is less than 500 poise, preferably less than 300 poise under spinning conditions. If the apparent viscosity is increased, the spun fibers will not become ultra-fine, resulting in a fiber web that is not suitable for the hydrophilic and bulky fiber-entangled nonwoven fabric that is the object of the present invention.

Additionally, additives added to impart hydrophilicity to hydrophobic polymer fibers include (1) In a composition of phosphoric ester or higher alcohol ethylene oxide-added phosphoric ester and polyethylene oxide or polyoxyethylene fatty fil ester, Phosphate ester has the general formula (RO姶P=
0 [However, R is a hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having an aromatic ring], higher alcohol ethylene oxide-adducted phosphoric acid ester has the general formula (RlO-(Cfi2CHzO) fused P model) OR2〕3-
□ [However, R1 is a hydrocarbon group having 4 to 24 carbon atoms, R2 is a hydrocarbon group having 1 to 20 carbon atoms, n is 8 to 50% m is 1 to
[an integer of 3], these phosphoric acid esters have an integer of 0.3 to the polymer. It is O1-2 weight rice cake.

Further, polyethylene oxide is a compound having an average molecular weight of 1300 or more, preferably 1i1500 to 5000, and polyethylene oxide fatty acid ester is a compound represented by a hydrocarbon group of the general formula %, where n is an integer of 8 to 50. The ethylene oxide compound is contained in an amount of 0.5 to 10% by weight based on the polymer.

(2) The m-tactile polyvinyl alcohol or vinyl alcohol copolymer is polyvinyl acetate or a saponified product of ethylene/vinyl acetate copolymerization with a saponification degree of 50 to 98 mol and a polymerization degree of 250 or less, The amount added is 1
~20% by weight.

(8) Higher alcohol or olefinic unsaturated (-7
) Carboxylic acid copolymer, the amount added is 1 to 15% by weight
It is.

At least one hydrophilic compound selected from the group of additives (1) to (8) is added during the process of spinning the hydrophobic polymer. The method of adding additives is differentiated depending on the polymer. For example, combinations of polymers and additives that, if left in a molten state for a long time, will cause exchange reactions or decomposition reactions, significantly changing the viscosity of the polymer, and impairing spinnability and fiber performance5. and a polyethylene oxide compound or an olefin-unsaturated (di)carmenic acid copolymer, a spinning system,
For example, by injecting the gas into the melt at the die section or by injecting it into the blown gas stream. In addition, for highly stable polymers, such as polyolefin polymers, methods such as mixing with chips, making kneaded chips and using them, charging them at the same time, or injecting them into a molten system are used. Therefore, we have carefully investigated the relationship between the polymer used and additives, and have determined whether they are added at the time of polymer production, added to the polymer melt system, or added to the die section or spinning system where the melt is spun out from the die. Add in either system. Further, the amount of the additive to be added is selected based on the required degree of hydrophilicity of the polymer, spinnability, and fiber performance. If the amount added is small, hydrophilicity cannot be expected.In order to increase the hydrophilicity of the fiber, it is sufficient to increase the amount added, but if the amount added exceeds the amount shown in the relationship between the additives and the amount added above, the spinnability, May have an undesirable effect on fiber performance.

Furthermore, in the present invention, it is possible to form a fiber flow with good homogeneity by spinning the polymer containing the additive so that the apparent melt viscosity at the temperature of the spinning conditions is 500 poise or less, preferably in the range of 300 to 100 poise. The fine fibers have good fiber dispersibility and can produce bulky fibrous webs. If the melt viscosity is low, the stiffness of the fibers will decrease, making it impossible to obtain a nonwoven fabric with good performance.

The fibrous web obtained by the method of the present invention is treated with heated calender rolls to form a nonwoven fabric with a desired morphology and density.

A flexible and bulky nonwoven fabric with good fiber entanglement can be obtained by subjecting a fiber web having a desired basis weight to an entanglement treatment using a needle punch method and/or a high-pressure fluid entanglement method.

The nonwoven fabric obtained here can be used alone, such as wiping cloth,
Suitable for use in various sanitary materials, filters, etc.

Furthermore, it is impregnated with a polymer emulsion liquid to form a nonwoven fabric sheet, which is suitable as a material for producing various molded objects.

〔Example〕

Next, embodiments of the present invention will be explained with specific examples.

It should be noted that parts and parts in the examples refer to weights unless otherwise specified.

In addition, the measured values in the Examples are based on the following test method.

(1) Initial water absorption rate: Approximately 0.29% of red ink is dropped onto a plastic plate. The time from the moment a 5×5 cn+ sample is placed on the red ink until the diffusion is almost completed is measured.

(2) Initial water absorption amount: Approximately 0.22 of red ink is dropped onto a plastic plate. After placing a 5×53 sample on top of the red ink, immediately remove the sample and measure the weight of water absorbed by the sample.

lO- (8) Initial water absorption rate; calculated from the value in item (2) above, [(Weight of water absorbed by the sample W)/(Weight of the sample before immersion Wo)) x 100 (4) Absolute water absorption amount; A 5×5 m sample is immersed in a beaker of water for 30 seconds. Thereafter, the sample is air-dried for 1 minute, and the weight of water absorbed by the sample is measured.

(5) Absolute water absorption rate: Calculated from the value in item (4) above, [(Weight of water absorbed by the sample W)/(Weight of the sample before immersion Wo)) x 100 (6)
Suction length; JIS L-1096, 6.26.1 (2)
Based on method B.

Example 1 80 parts of high-flow low-density polyethylene [melt index (hereinafter referred to as MI) 205], 4% polyethylene oxide fatty acid ester based on low-density polyethylene, ethylene oxide-added phosphate ester (surfactant) IL
20 parts of the chips kneaded with 20% of the chips were mixed, charged into a melt extruder, and the melted product was prepared by arranging holes in the nozzle with a diameter of 0.3 mm in a row at intervals of 1 inch, and holes with a width of 0.3 mm on both sides of the nozzle. Using a die head equipped with a 25-inch slit-shaped gas outlet, the discharge rate per spinning hole was 0.2 r under the conditions of polymer melting temperature of 280°C, injection heated air temperature of 300°C, and hot air pressure of 1.2 kg/ca. /min amount was spun. Note that the apparent melt viscosity under the discharge temperature conditions was 178 voids.

The spun jet fiber stream was collected on the mesh surface of a mesh belt conveyor collection device running at a position approximately 25 (7) below the spinning hole, and was collected with an average basis weight of 50 f/rr? A fibrous web was obtained. In this fiber web, almost no molten beads were observed, and the homogeneity of the dispersed and accumulated state of the fibers was also good.

Next, the fiber web was rolled at a roll temperature of 100°C and a crimped area of 1
Embossing was performed using an embossing calender set at 5 inches to obtain a nonwoven fabric with adhesive formed in some of the contact areas of the fibers. This nonwoven fabric was very flexible. Its performance is shown below.

Cutting strength (vertical-horizontal) (ume/bei) 0.22-0.
19 Cutting elongation (vertical-horizontal) (%') 145-
126 Initial water absorption rate (sec) 0.8
(2,11 initial water absorption amount (r) 0.2
01 (0,066:) Initial water absorption rate (%)
141 [46,3] Absolute water absorption (
9) 1.268 [0,325] Absolute water absorption rate
(%) 923 (233) Suction length (
Vertical-Horizontal) (■) 101-118 (However,
[Numbers in parentheses indicate comparative example values] For comparison, a fibrous web was made by the meltpron method in Example 1 without using a surfactant and with the other conditions being the same. The resulting fibrous web was embossed using an embossing calender, and the resulting nonwoven fabric had low water absorption.

Furthermore, when both nonwoven fabric traps were allowed to absorb machine oil, the nonwoven fabric of the present invention had good oil absorption and oil retention properties, and was excellent in performance as a wiping cloth.

Example 2 Using 6-66-copolymerized polyamide tep, Example 1
When spinning with the same melt blown equipment as above, various additives are injected and mixed into the melt system in fixed amounts using the proportional injection method.
Nozzle temperature 310℃, injection heating air temperature 340℃, heating air pressure 2.5kp/cm! .

Spinning was carried out under conditions of a discharge rate of 0.2 f/min per spinning hole.

Then, the spun jet fiber stream was collected as a fiber web with an average basis weight of 50 f/♂ on the mesh surface of a mesh belt conveyor collecting device running at a position approximately 25 cm below the spinning hole.

Two sheets of the obtained fibrous web were laminated and treated five times with a columnar stream of water sprayed at a water pressure of 30 kp/- from a nozzle in which holes with a diameter of 0.1 m were arranged in a row to produce a fiber-entangled nonwoven fabric. .

Table 1 shows the relationship between various additives and the state of the nonwoven fabric.

Note that there was almost no loss of additives even after water treatment, and the sample had good hydrophilicity.

That is, when the copolyamide does not have any additives (sample 1), it is spun in the form of ultrafine fibers and becomes a densely accumulated fiber web, which cannot be sufficiently entangled by the entanglement treatment. In addition, when a large amount of additives is added, the spun fiber becomes thick and non-uniform, resulting in frequent occurrence of loose pieces (Sample 7),
The stiffness of the fibers decreases and the accumulated fiber mat becomes dense, resulting in poor entanglement properties during the entanglement treatment (Sample 12). On the other hand, in the range of Examples, the thickness of the spun fibers was uniform and good fiber flow was formed, so the fiber entanglement of the accumulated fiber mat was good and a bulky nonwoven fabric was obtained.

This fiber-entangled nonwoven fabric was suitable for use as a water-absorbing wiping cloth. Furthermore, as another usage example, impregnating with polyether-based polyurethane emulsion liquid,
When resin-impregnated nonwoven fabrics were made, the nonwoven fabrics of Examples had good impregnating properties, and the entire nonwoven fabric was impregnated uniformly, whereas Sample 1% 12 of Comparative Example was impregnated only on a narrow surface. This resin-impregnated nonwoven fabric was suitable as a first material for press molding.

〔Effect of the invention〕

The present invention makes it possible to obtain a flexible nonwoven fabric in which long-lasting hydrophilicity is imparted to a fibrous web obtained from a thermoplastic hydrophobic polymer. Furthermore, in the production of fiber webs using the melt-blown method, it is possible to form a good #1# flow without reducing spinnability, resulting in good fiber accumulation, bulkiness, and entanglement processing. A nonwoven fabric with good properties can be obtained.0 Patent applicant RiRa Shi Co., Ltd.

Claims (3)

[Claims] (1) When spinning a hydrophobic polymer melt using a high-temperature, high-pressure gas flow to form a fiber stream to produce a fiber web, in the process up to spinning the hydrophobic polymer melt, (
1) Composition of phosphoric ester or higher alcohol ethylene oxide-added phosphoric ester and polyethylene oxide or polyethylene oxide fatty acid ester, (2) Melting polyvinyl alcohol or vinyl alcohol copolymer, (3) A method for producing a hydrophilic nonwoven fabric, which comprises adding at least one hydrophilic compound selected from the group of higher alcohols and olefin unsaturated (di)carboxylic acid copolymers.