JPH0765268B2 - Method of modifying synthetic fibers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for uniformly and economically modifying synthetic fibers with high reaction efficiency.

(Prior Art) Conventionally, as a method for efficiently graft-polymerizing a hydrophilic vinyl monomer onto a hydrophobic synthetic fiber, there are JP-B-59-5126 and JP-A-51-87592.

The former relates to a monomer composition for a two-step method in a bath in which graft polymerization is carried out after activation pretreatment, but it is uneconomical because it requires two steps of activation pretreatment and graft polymerization. The latter relates to a one-step method in a bath that does not require pretreatment for activation, but such a dipping heating method in a bath has a large amount of unreacted monomer and the graft reaction efficiency is not high, so that a large amount of homogenization occurs in the bath. There is also the problem of polymer contamination of processing machines, and also of wastewater.
Therefore, it is hard to say that it is economical overall.

(Means for Solving the Problems) In order to solve the above problems, the method for modifying synthetic fibers of the present invention has the following constitution. That is, in a method of modifying a synthetic fiber by graft-polymerizing a hydrophilic vinyl monomer, a water-based mixed solution comprising a graft polymerization initiator, a hydrophilic vinyl monomer and a water-soluble organic solvent having a solubility parameter (SP) value of 9.5 or more. Is applied to the synthetic fiber, sealed with a vinylidene chloride film, and heated, and the synthetic fiber is modified.

(Explanation of Means) The synthetic fiber as referred to in the present invention is a fiber made of an ordinary fiber-forming synthetic resin, and includes, for example, polyalkylene terephthalate fiber, polyamide fiber, polyolefin resin, polyacrylonitrile fiber and the like. Further, it includes fibers made of these modified polymers, or a mixture thereof, or a mixed fiber of various forms in which natural fibers are used in combination. The form of these synthetic fibers may be tow, yarn, knitted fabric, non-woven fabric or the like. The SP value (solvability parameter value) of various compounds is one of the parameters indicating the solubility characteristics of a solvent, as described in, for example, Fiber Processing Vol.26 No.6 (1974).

The SP value is expressed as σ, and is generally calculated as the square root of the cohesive energy density. For polar molecules, the method of obtaining from the heat of vaporization, the method of obtaining from the boiling point, the method of obtaining from the surface tension or the method of obtaining from solubility, etc. There is.

The water-soluble organic solvent having a SP value of 9.5 or more as used in the present invention is generally used as an organic solvent or a chemical agent. For example, alcohols include monohydric alcohols such as methanol, ethanol and propanol, ethylene glycol and propylene. Polyhydric alcohols such as glycol and glycerin are included. Examples of ketones include acetone and acetonitrile.

Examples of amines include pyridine and monoethanolamine. Examples of ethers include diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol ethyl ether and the like.

Examples of acid amides include N, N-dimethylformamide, N, N-dimethylacetamide and the like. Examples of the acids include formic acid, acetic acid, propionic acid and the like. Oxyacids include, for example, lactic acid, but are not limited to these. These SP value 9.5
The above water-soluble organic solvents are added for the purpose of stabilizing the solution. These can be used alone or in 2
It may be used in combination of one or more kinds or in combination with a surfactant.

Among organic solvents having an SP value of 9.5 or more, those having an SP value of 12 or more are preferable, and acetic acid, lactic acid, dimethylformamide, ethylene glycol and glycerin are particularly preferable. Of these, the use of acetic acid, dimethylformamide, and lactic acid is the most preferable from the viewpoints of low amount used for liquid stabilization and graft efficiency.

A water-soluble organic solvent with an SP value of less than 9.5, such as diacetone alcohol, or a poorly water-soluble organic solvent with an SP value of 9.5 or more, such as methyl oxalate, makes it difficult to obtain a stable aqueous mixed solution, and it is difficult to obtain it in a short time. A layer separation occurs and it cannot be used for a uniform reaction.

The hydrophilic vinyl monomer as used in the present invention is a compound which is usually applied to graft polymerization and contains at least one polymerizable unsaturated group, and can be applied regardless of the molecular weight.

Examples of such monomers include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, and unsaturated amides such as acrylamide, methacrylamide, N-methylol acrylamide and vinylpyrrolidone, and vinyl. Unsaturated phosphorus compounds such as phosphonic acid and vinyl sulfonic acid,
Various unsaturated compounds such as unsaturated aromatic compounds such as styrene sulfonic acid can be mentioned. Derivatives of these monomers may also be applied in the present invention.

Examples of such derivative compounds include various compounds obtained by adding ethylene oxide to the above-mentioned monomers, such as polyethylene glycol monoacrylate, polyethylene glycol dimethacrylate, and acrylamide ethylene oxide adduct, but are not limited to these monomers. It is not necessary, and in short, any compound containing a polymerizable unsaturated group can be applied as the mokumer of the present invention. These monomers can be used alone or in combination of two or more.

Examples of the graft polymerization initiator in the present invention include, for example,
It is a radical polymerization initiator such as benzoyl peroxide and azobisisobutyronitrile, but is not limited thereto.

In the present invention, it is not particularly necessary to add a fiber swelling agent, but it is also possible to add a fiber swelling agent according to the purpose,
As such a fiber swelling agent, compounds such as chlorobenzene type, phenol type and benzoic acid type can be applied.

The present invention includes a hydrophilic vinyl monomer, a graft polymerization initiator,
If necessary, keep the aqueous mixture containing a fiber swelling agent in an extremely uniform and stable state, apply the aqueous mixture to the synthetic fibers by padding, and then heat the mixture.
Graft polymerization is carried out in a group of processing steps. At that time, in order to make the aqueous mixed solution extremely uniform and stable, it is characterized by adding a water-soluble organic solvent with a SP value of 9.5 or more. is there.

It is preferable that the concentration of the hydrophilic vinyl monomer in the aqueous mixture is adjusted to the range of 5 to 70%. Below this range, the stability of the solution is extremely reduced and the grafting efficiency is also reduced. Further, if it exceeds this range, the graft efficiency is lowered, which is considered to be the reduction of the carrier effect of water. The amount of water-soluble organic solvent with SP value 9.5 or more changes depending on the monomer concentration, polymerization initiator concentration, fiber swelling agent concentration, liquid temperature, and the type of water-soluble organic solvent with SP 9.5 or more, Although difficult to determine, the point is to obtain a uniform and extremely stable aqueous mixture.

The concentration of the graft polymerization initiator is preferably in the range of 0.1% to 3.0%. If the concentration is out of this range, the generation of homopolymer will increase and the graft polymerization efficiency will decrease. Although the fiber swelling agent is not particularly required as described above, the concentration when added is preferably 5% or less as a pure product. If it exceeds this, the graft polymerization efficiency will decrease.

The order of adding the hydrophilic vinyl monomer and the graft polymerization initiator is not particularly limited, but if it is strong, first dissolve the hydrophilic vinyl monomer graft polymerization initiator and then add S
It is preferable to add water-soluble organic solvents having a P value of 9.5 or more and water.

The required amount of the aqueous mixed solution containing the monomer thus prepared is applied to the synthetic fiber by a padding method or the like. As another application method, a method of spraying, coating, dipping and then squeezing with a centrifugal dehydrator can be considered, and can be appropriately selected depending on the form of the object to be treated, the required application amount, and the like. The object to be treated to which the aqueous mixed solution containing such a monomer is applied is sealed with a vinylidene chloride film and then transferred to a heating system. If not sealed with a vinylidene chloride film, the hydrophilic monomer will evaporate and the grafting efficiency for the fiber will be significantly reduced. When the object to be processed transferred to the heating system is allowed to stand and subjected to heat treatment, the processing solution usually moves downward due to its own weight, and preferably the solution does not move due to centrifugal force. It is preferable that the liquid is kept in a state where the liquid movement is small by rotating the liquid to a certain degree.

As the heating means, a usual heating mechanism can be applied, but preferably heating by microwaves or a combination of steam and microwaves can be selected in view of the rate of temperature rise and ease of control.

In the case of this heating method, the temperature rising rate and the maximum temperature differ depending on the requirements such as the frequency, the type and amount of the dielectric material, and the moving speed of the object to be processed. Maximum temperature can be regulated.

The temperature condition is usually 80 ° C or higher, preferably 100 ° C or higher, and at most 180 ° C, although it is somewhat different depending on the type of graft polymerization initiator and the type of monomer. The modified synthetic fiber obtained by graft-polymerizing the unsaturated carboxylic acid monomer is further subjected to substitution treatment with an alkali metal such as sodium or potassium by a conventional method to obtain a hydrophilic property such as antistatic property or hygroscopic property. Further improvement can be expected, and antibacterial performance can be imparted by substitution treatment with a quaternary ammonium salt.

(Example) Example 1 As a graft polymerization initiator, 0.5 g of an organic peroxide (NIPPER Mfg. Co., Ltd., Niper MT-80), a hydrophilic vinyl monomer, 30 g of methacrylic acid, a water-soluble organic solvent having a SP value of 9.5 or more,
Acetic acid (5 g) was added and diluted with water to prepare 100 g of an aqueous mixed solution. Next, a polyethylene terephthalate-processed yarn fabric (Toray # 2525) with a refined intermediate set was dipped in the aqueous mixture, squeezed with a mangle, wound on a roll, and sealed with a vinylidene chloride film. At this time, the pick-up rate was 70% with respect to the weight of the textured yarn woven fabric. Next, the fabric was placed in a microwave treatment device (Apollopet made by Ichikin) 10
After heating and irradiating with steam and microwave for 5 minutes at 0 ° C, the weight increase rate with respect to the initial weight of the woven fabric was obtained after washing with hot water and drying.

The reaction efficiency of the monomer corresponding to the weight increase rate was calculated as follows, taking the pickup rate into consideration. The results are shown in Table 1.

Monomer reaction efficiency = Grafting efficiency Grafting efficiency (%) = [weight increase rate ÷ 0.7 × monomer concentration] × 100 [in the formula, weight increase rate:% by weight, monomer concentration: weight fraction] Comparative Example 1 SP of Example 1 Instead of dimethylformamide, a water-soluble organic solvent with a value of 9.5 or more, 40% of (acetone) with a SP value of 9.2 (water-soluble organic solvent) was added.

In Example 1, a uniform and stable aqueous mixture was obtained,
In Comparative Example 1, the mixed solution was separated into two layers and was unsuitable as a pad solution.

Comparative Example 2 Graft Polymerization Initiator (Nippon Oil & Fat: Nyper MT-80) 2
g, polyethylene terephthalate fiber swelling agent: monochlorobenzene 10 g, as an emulsifier (Nippon Yushi Co., Ltd .: Neugen EA
160) 5g Dilute 20g of 1: 1 (weight) mixture of acrylic acid and methacrylic acid as hydrophilic vinyl monomer with water to obtain 1000m
l Next, add 300 ml of this solution to a polyethylene terephthalate-processed yarn fabric (Toray # 2525) with a refined intermediate set up.
10 g was immersed and heat-treated at 100 ° C. for 60 minutes. Then, after washing with hot water and drying, the weight increase rate with respect to the initial textured yarn fabric was obtained, and the grafting efficiency was obtained by the following formula. This result is the first
Shown in the table.

[In the formula: weight increase rate: weight ratio] As is clear from Table 1, the woven fabric obtained by the graft polymerization treatment in one step using the aqueous mixture obtained in Example 1 had a high graft efficiency, but the graft polymerization treatment was performed in one step in the bath. The grafting efficiency in Comparative Example 3 performed was low. Also, instead of a water-soluble organic solvent with an SP value of 9.5 or higher, SP
Comparative Example 1 using a water-soluble organic solvent with a value of less than 9.5, and SP
Comparative Example 2 using an organic solvent having a value of 9.5 or more did not form a stable water-based mixed solution, and could not perform the one-step graft polymerization treatment.

Comparative Example 3 Immersion in an aqueous mixed solution, squeezing with a mangle, winding with a roll, and heating with microwave under the same conditions as in Example 1 except that the film was not sealed with a vinylidene chloride film. Was extremely low at 9.1%.

(Effects of the Invention) The present invention can uniformly and extremely economically modify synthetic fibers with high reaction efficiency. Further, at the time of heating, it is possible to prevent the hydrophilic monomer from scattering and prevent the graft ratio from decreasing.

Claims (2)

[Claims] 1. A method for modifying a synthetic fiber by graft-polymerizing a hydrophilic vinyl monomer, which comprises a graft polymerization initiator, a hydrophilic vinyl monomer and a water-soluble organic solvent having a solubility parameter (SP) value of 9.5 or more. A method for modifying synthetic fibers, which comprises applying an aqueous liquid mixture to the synthetic fibers, sealing with a vinylidene chloride film, and heating. 2. The method for modifying synthetic fibers according to claim 1, wherein the heating means is a microwave or a combination of steam and microwave.