JP2752450B2 - Water repellent for binder fiber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water repellent agent for binder fibers.

2. Related Art and Problems Conventionally, fibers having a low-melting thermoplastic polymer called a binder fiber or a heat-fusible fiber in a surface layer have been used as a raw yarn for a nonwoven fabric. The binder fiber does not require a special adhesive during the production of the nonwoven fabric, and can provide a nonwoven fabric having good water resistance. Accordingly, as one of the main uses of the binder fiber, there are surface materials for water-absorbing materials such as diapers and sanitary napkins. Since these surface materials are in direct contact with the skin, a feeling of dryness when worn is important, and therefore, a property that the surface is not sticky, that is, water repellency is required.

On the other hand, the binder fiber is obtained by cutting the filament into a predetermined length, carding, forming a web and heat-treating the web to form a nonwoven fabric.However, in order to suppress frictional static electricity generated between the fiber and the metal during carding, It is treated with an antistatic agent such as an alkyl sulfate salt or an alkyl sulfonate salt. However, nonwoven fabrics treated with these antistatic agents cannot avoid sticky feeling when worn on the skin as they are. Conventionally, in order to solve this problem, after manufacturing the nonwoven fabric, the antistatic agent was removed and a water-repellent treatment was performed. This leads to an increase in the number of steps and is a troublesome operation.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a binder fiber water-repellent agent for improving the card permeability of a binder fiber and imparting water repellency thereto.

Means for Solving the Problems The present invention relates to an alkyl phosphate having 14 or more carbon atoms; a carboxy-modified polyethylene wax having a molecular weight of 1,000 to 10,000 and an acid value of 5 to 50; an emulsifier; a binder fiber containing a higher alcohol and dimethyl silicone or a modified product thereof. Water-repellent treatment agent.

The alkyl phosphate used in the present invention has an average carbon number of 14 or more, preferably 14 to 22, more preferably 16 to 18.
Which may be an unneutralized product, a partially neutralized product, or a completely neutralized product. Examples of the salt include an alkali metal salt, an alkaline earth metal salt, and a zinc salt. , Zirconium salts, ammonium salts, alkanolamine salts, amine salts and the like are exemplified, but alkali metal salts are preferred, and completely neutralized products are particularly preferred.

This alkyl phosphate is used particularly for the purpose of preventing static electricity. However, when the average carbon number of the alkyl group is smaller than 14, the water repellency decreases, which is not preferable.

The amount of the alkyl phosphate is preferably 20 to 45% by weight (in terms of solid content) of the total solid content of the treating agent composition,
More preferably, it is 25 to 35% by weight. 20% by weight
If the amount is smaller, the antistatic property is insufficient, and if it is larger, the water repellency is insufficient.

The carboxy-modified polyethylene wax used in the present invention has a carboxyl group in a part of the polyethylene chain, and preferably has a molecular weight of 1,000 to 10,000 and an acid value of 5 to 50. Particularly preferred carboxy-modified polyethylene has a molecular weight of 3000 to 5000 and an acid value of 10 to 30. The carboxyl group may be neutralized or unneutralized. If necessary, a self-emulsifying type may be obtained by esterification with polyethylene glycol or the like. Neutralization may be performed using an alkali metal, ammonia, alkanolamine, amine or the like.

When the carboxy-modified polyethylene wax used in the present invention is blended with the treating agent of the present invention, it is preferable to use an emulsified O / W type in advance. The emulsification may be self-emulsifying or may be carried out using a suitable surfactant. The surfactant is effective in as small an amount as possible, and in particular, a nonionic surfactant is preferable in that sense. The surfactant is used in an amount of 50% by weight or less, more preferably 5 to 30% by weight, based on the wax. Of course, when the same surfactant as the emulsifier described below is used, it may be used in a larger amount, but generally, this surfactant is used to make the carboxy-modified polyethylene wax as uniform and stable as possible. It should be used, and thus may be of a different kind than the emulsifiers described below. In this case, it is preferable to use this surfactant in as small an amount as possible so as not to affect the subsequent emulsification.

The carboxy-modified polyethylene wax is obtained by uniformly mixing a suitable surfactant in a molten wax, stirring this under strong shearing force, and emulsifying it in water.

Generally, a carboxy-modified polyethylene wax 10 to 50% by weight emulsion is sold under the trade name of Marposol PO or the like, and it may be used as it is.

The compounding amount of the carboxy-modified polyethylene wax is preferably 20 to 70% by weight (solid content), more preferably 30 to 50% by weight (solid content) of the solid content of the treating agent composition.
When the wax content is less than 20% by weight, water repellency is insufficient, and when the content is more than 70% by weight, card permeability is insufficient.

The emulsifier used in the present invention is used to emulsify the carboxy-modified polyethylene wax, neutral oil, dimethyl silicone, and the like in water.

As described above, the carboxy-modified polyethylene wax is preferably emulsified in advance and then used by mixing with other components. Therefore, the emulsifier used herein is used separately from the above-described surfactant for emulsifying the wax. Of course, both may be the same composition or may be different.

The emulsifier is not particularly limited, but when targeting nonwoven fabrics for use in diapers and sanitary napkins, etc., anionic surfactants and / or nonionic surfactants that are in direct contact with the skin and cause little skin damage It is preferred to choose from agents.

Representative anionic surfactants are sulfonates and phosphonates. In particular, phosphonates are used as an antistatic agent as described above, and are preferred because a single component can serve both as an antistatic effect and as an emulsifying effect. Of course, the emulsifier used in the present invention is for achieving emulsification of the system, and therefore, if necessary, another emulsifier may be used.

The phosphate is preferably the same as the alkyl phosphate described for the antistatic agent, but a phosphate having a smaller alkyl group or a phosphate having an aromatic group may be used.

Examples of the sulfonate include petroleum sulfonic acid, alkylbenzene sulfonate and the like, but use of a large amount tends to increase the sticky feeling of the nonwoven fabric.

As an emulsifier, a sulfate such as an alkyl sulfate, a polyoxyethylene alkyl sulfate, or a funnel oil may be used.

As nonionic surfactants, polyoxyethylene alkyl ether, polyoxyethylene aryl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene sorbitan alkyl ester, polyoxyethylene pentaerythritol alkyl ester,
Polyethylene glycol alkyl ester, glycerin monoaliphatic ester, pentaerythritol fatty acid ester, sorbitan fatty acid ester, sugar ester,
Various types such as polyglyceride and lecithin are exemplified, but the ether type is particularly preferable from the viewpoint that the emulsifying power is small and large. The hydrophobic group of the nonionic surfactant has 8 or more carbon atoms, preferably 8 to 22, and more preferably 12 to 18 carbon atoms.
Of these, a saturated or unsaturated alkyl group which may have a side chain is preferred. If the number of carbon atoms is less than 8, card passing properties tend to decrease.

The number of moles of ethylene oxide added to the nonionic surfactant may be selected so as to provide an HLB suitable for achieving the desired emulsification.

A part of the oxyethylene chain may be replaced by another oxyalkylene chain, for example, an oxypropylene chain.

The amount of emulsifier used is preferably 5% of the total solids weight of the composition.
-30% by weight, especially 10-20% by weight. When the amount of the emulsifier is less than 5% by weight, the emulsifiability is insufficient, and when the amount is more than 30% by weight, the nonwoven fabric becomes sticky.

 The composition of the present invention further contains a neutral oil.

The purpose of blending the neutral oil is effective for improving card passing property (suppressing friction and static electricity generation) and water repellency when spinning the binder fiber.

Examples of the neutral oil include higher alcohols and coconut oil, but higher alcohols are particularly preferable. The higher alcohol used in the present invention has 12 or more carbon atoms, preferably 14 carbon atoms.
Saturated or unsaturated alcohols which may have up to 22 side chains, such as cetyl alcohol, oleyl alcohol, stearyl alcohol and the like.

The neutral oil is preferably incorporated in an amount of 5 to 10% by weight based on the total weight of the solid content of the treatment composition.

Dimethyl silicone or a modified product thereof is used for the purpose of imparting water repellency and smoothness. As dimethylsilicon or a modified form thereof that can be used, those having a viscosity of 20 to 100 cst (25 ° C.) are preferable. Examples of the modifying group include a phenyl group and an alkylphenyl group. Usually, dimethyl silicone is used.

The amount of dimethyl silicone or a modified product thereof is preferably 2 to 5% by weight based on the total solid content of the treatment composition. 2
When the amount is less than 5% by weight, the smoothness is insufficient, and the card passing property is insufficient. When the amount is more than 5% by weight, the antistatic property is insufficient, and the web is disturbed, which is a quality problem.

The treating agent of the present invention basically contains the above-mentioned components. However, if necessary, other components such as a preservative and the like may be blended.

The treating agent of the present invention is a suitable solvent, for example, water, methanol,
It is dissolved or dispersed in acetone, hexane, or the like, and is applied to the fiber in a predetermined amount before carding. The amount of the treatment agent applied to the fibers is preferably 0.01 to 3% by weight, more preferably 0.1 to 0.7% by weight, in terms of solid content. The application method may be any suitable means such as immersion, contact, spraying, and the like.

The standard for the amount of adhesion is such that the water repellency measured by the method shown in the examples is 4 or more and the antistatic property (20 ° C., 50% RH) is 0.5 KV or less.

Examples of the target fiber include polyester, polyolefin, acrylic, vinylon, nylon, rayon, and the like, or a composite fiber thereof.

Since the treating agent of the present invention has the opposite properties of antistatic action and water repellent action, it is not necessary to perform antistatic during carding and water repellent treatment after nonwoven fabric production with separate treating agents as in the conventional case. .

 Hereinafter, the present invention will be described with reference to examples.

Examples 1 and 2 and Comparative Examples 1 to 5 A water repellent agent for binder fibers having the formulation shown in Table 1 was prepared, and 10 parts by weight thereof was dispersed in 1000 parts by weight of water. : Core polypropylene, 2de x 51mm) 100 parts by weight dipped and squeezed to 40% to refuel
0.4% by weight of binder fiber was obtained. After drying the binder fiber, it is carded at 20 ° C. and 50% RH for 30 minutes.
g / m ² web was obtained and heat treated at 140 ° C. for 5 minutes to obtain a nonwoven fabric.

The antistatic property of the oiled cotton obtained in the above step and the water repellency of the nonwoven fabric were measured by the following methods. Table 1 shows the obtained results.

Water repellency: Five minutes after placing the IPA aqueous solution on the nonwoven fabric, the highest series in which the shape of the droplet is maintained is evaluated.

Class 1: IPA / Water (2/98) Class 2: IPA / Water (5/95) Class 3: IPA / Water (10/90) Class 4: IPA / Water (20/80) Class 5: IPA / Water (30/70) Grade 6: IPA / Water (40/60) Grade 7: IPA / Water (50/50) Grade 8: IPA / Water (60/40) Antistatic properties: Oil-treated cotton at 20 ° C 50% It is inserted into a flat card in an atmosphere of RH and the amount of static electricity immediately after passing through the doffer is measured.

Effect of the Invention When the treatment agent of the present invention is used, an antistatic effect and a water repellent effect can be simultaneously achieved, so that the obtained nonwoven fabric can be used for diapers and napkins without water repellent treatment again. This nonwoven fabric has no stickiness when worn on the skin and has a good feeling of use.

Claims (1)

(57) [Claims] 1. A carboxy-modified polyethylene wax having a molecular weight of 1,000 to 10,000 and an acid value of 5 to 50, comprising 20 to 45% by weight of an alkyl phosphate having 14 or more carbon atoms and containing 5 to 30% by weight of an emulsifier;
Water-repellent agent for binder fibers, containing 2% to 5% by weight of dimethyl silicone or a modified product thereof.