JPH0231152B2 - HORIAMIDOKEISENIKOZOBUTSUNOKOSHUHAJUDENKANETSUYOSETSUNOKAIRYOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for improving high frequency dielectric heating welding of polyamide fiber structures, and more particularly to a method for imparting excellent high frequency dielectric heating welding performance to polyamide fiber structures. Conventionally, sewing of common textile structures such as woven and knitted materials has been carried out using sewing machines, but in recent years, sheets, films, foams, etc. have also been used as sewing materials, so thermal welding has become popular in addition to sewing using sewing machines. Among these, high-frequency dielectric heating welding is attracting attention. High frequency dielectric heating welding is a type of thermal welding that takes advantage of the thermoplastic properties and electrical insulation properties of adherends. In this welding method, when the welded surfaces soften and melt, it is not enough to simply bring them into contact; it is necessary to create an entangled state of molecules between the two surfaces while the molecules are undergoing intense Brownian motion. be. In the welding method based on such a principle, the bonding strength may be insufficient when the adherends are made of the same type of material or different types of materials, so weldable resin such as polyamide resin is used as an auxiliary agent. A method is known in which a coating material such as a bonding agent is applied to the surface of an adherend and welding is performed. Polyamide fiber structures are useful for clothing and industrial materials, but when using this method, it is easy to weld due to their high dielectric properties, but the range of conditions for high-frequency dielectric heating welding is narrow, making it difficult to weld. It is non-uniform, and the molten material during welding is very prone to eluting to areas other than the welded area.These drawbacks increase the loss rate of defective products and reduce workability, so it is difficult to use a stable welding method. development was desired. As a result of extensive research, the present inventors have discovered a method for improving high-frequency dielectric heating welding of polyamide fiber structures by modifying the adherend polyamide structure with a graft polymer to improve weldability. . That is, the present invention provides a polyamide fiber structure with an unsaturated carboxylic acid, its anhydride, or a hydrolyzable functional derivative thereof, graft polymerizes it, and then converts the carboxyl group in the graft polymer into a polyamide fiber structure according to the periodic table. The object of the present invention is to provide a method of converting the polyamide fiber structure into a Group 1 or Group 2 metal salt and performing high-frequency dielectric heating welding using the thus obtained polyamide fiber structure. The polyamide fiber structure used here is
Nylon 4, Nylon 6, Nylon 66, Nylon
10, polyamides such as nylon 12, or mixtures or copolymers of two or more of these. Its forming forms include tow yarn, woven fabric, knitted fabric,
Non-woven fabrics, carpets, and other materials may be used. Although not particularly limited, polyamide structures such as nylon 6 and nylon 66, and fibrous structures containing 50% or more of polyamide fibers are particularly preferred. Unsaturated carboxylic acids are carboxylic acids with polymerizable double bonds such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid, and unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, etc. Anhydrides of the above carboxylic acids such as acids.
In addition, hydrolyzable functional derivatives of unsaturated carboxylic acids refer to compounds that produce the original carboxylic acid through simple hydrolysis, and include unsaturated acid esters, unsaturated amides, unsaturated nitriles, etc. be. These unsaturated carboxylic acids may be used alone or in combination of two or more. Other polymerizable monomers include monofunctional polymerizable monomers and polyfunctional polymerizable monomers. A monofunctional polymerizable monomer is one vinyl group in the monomer,
A polyfunctional polymerizable monomer is a monomer that has a polymerizable double bond such as an allyl group or an acryloyl group. It has a bond. These may be used alone or in combination of two or more. Graft polymerization treatment is performed by applying an aqueous solution or water emulsion containing the monomer described in the present invention to a polyamide fiber structure by a known method such as a dipping method, a pudding method, or a spray method, and then heat-treating it. It is done by folding. As the heat treatment method, immersion heating method, normal pressure or high pressure steam heating method, high frequency heating method, infrared heating method, ultraviolet heating method, dry heat heating method, etc., and combination methods thereof are used depending on the difference in the fiber structure. If necessary, catalysts such as peroxides, persulfates, etc. can be used to increase the efficiency of the heat treatment. The temperature required for the heat treatment is in the range of 30 to 200°C and the time is 0.05 to 60 minutes, preferably 50 to 180°C and 1 to 20 minutes. The monomer concentration is 5 as an aqueous solution or water emulsion.
The amount of the monomer fixed on the fiber structure is preferably 2 to 15% by weight. The monomer is used in combination with one or more of unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, or hydrolyzable functional derivatives of unsaturated carboxylic acids, and other polymerizable monomers as necessary. . The blending ratio is 1:0.05 to 1:3, especially 1:0.1 to 1:
A range of 0.5 gives good results. In the present invention, the carboxyl group of the graft-polymerized unsaturated carboxylic acid is converted into a salt form and then subjected to high frequency dielectric heating. For conversion to salts, if the carboxyl group of the unsaturated carboxylic acid used is free, it may be treated with an aqueous solution of a hydroxide or the like of a Group 1 or Group 2 metal of the periodic table, as described below. In the case of acid anhydrides, the above treatment may be carried out directly or through hydrolysis. In the case of a hydrolyzable functional derivative, it is sufficient to first hydrolyze it with an acid or alkali and then perform the above treatment. A known method may be appropriately used to convert these carboxyl groups into salts. Furthermore, after graft polymerization or hydrolysis, the terminal carboxylic acid groups of the grafted material on the polyamide fiber structure are H ⁺ , but Na ⁺ , Ca ⁺⁺ ,
In order to convert it into Mg ⁺⁺ , Zn ⁺⁺ , Li ^{+ ,} etc., it is preferable to treat it with an aqueous solution of a hydroxide or salt of a group metal or group metal of the periodic table. Common compounds used in this process include NaOH,
Hydroxides such as KOH, Ca(OH) ₂ , Mg(OH) ₂ ,
There are carbonate compounds such as Na ₂ CO ₃ , Ca(CO ₃ ) ₂ , Mg(CO ₃ ) ₂ and chlorides such as NaCl, KCl, CaCl ₂ , MgCl ₂ and LiCl. Note that the salt can be obtained directly by using a sufficient amount of NaOH or the like to form a salt during hydrolysis with an alkali. High-frequency dielectric heating welding is performed using a commercially available high-frequency welder, but the model is not particularly limited. Welding processing conditions vary depending on the combination of materials and pretreatment, but generally the oscillation frequency is 27.12MHz, or
40.46MHz, high frequency output 1~50W/ ^cm2 , pressure 2~
It is desirable to carry out at 100Kg/cm ² and for a time of 1 to 10 seconds. The expansion of welding compatibility in high-frequency dielectric heating welding of polyamide adherends obtained by the above method is generally applicable to thermoplastic polymer compounds.
One of the reasons for this seems to be that the melting point of the polymer compound increases by introducing a polar group and a polar metal base into the polymer compound. Hereinafter, the present invention will be explained in detail based on examples. Example 1 A 30D polyamide tricot was used which had been scoured and preset in the usual manner. monomer (1), monomer
(2), monomer (3), and monomer (4).

[Table] Made by 〓)
Each solution was treated individually in a closed dyeing container at a bath ratio of 1:42, heated from 50°C at a rate of 1°C/min, heated to 70°C for 30 minutes, and washed with water. after that,
Treatment, washing with water, and drying were performed at 50° C. for 10 minutes using 10 g of calcium chloride/solution at a bath ratio of 1:42. This adherend obtained in the above manner and the polyurethane foam were layered and heated using a high frequency dielectric heating device (manufactured by Yamamoto Vinita) at an oscillation frequency of 27.12 MHz, an output of 7 kW, a pressure of 5 Kg/cm ² , and a fusion time of 4 seconds. Welded under the following conditions. Comparative Example 1 In order to compare the effects of the present invention, the same tricots as in Example 1 were welded under the same conditions as in Example 1 without being treated. Table 1 summarizes the effects of the present invention.

[Table] Example 2 A 75D nylon 66 taffeta (fabric weight 70 g/m ² ) fabric was scoured and preset as usual, and dyed using acid dye (Aminyl Blue E-2GL 0.5% owf Sumitomo Chemical) using a conventional method. It was used. Methacrylic acid 6% owf, N-methylolacrylamide 1.5% owf, ammonium persulfate 0.2
A solution of %owf was prepared, and using a beam dyeing machine at a bath ratio of 1:20, the temperature was raised from 50°C at a rate of 1°C/min, treated at 70°C for 30 minutes, washed with water, and dried. Two sheets of the adherends obtained as described above were stacked on top of each other and welded under the same conditions as in Example 1. Comparative Example 2 In order to compare the effects of the present invention, two fabrics dyed in the same way as in Example 2 were stacked together without any treatment and welded under the same conditions as in Example 1. Comparative Example 3 In order to compare the effects of the present invention, a fabric dyed in the same manner as in Example 2 was used. Butyl polyacrylate (w.
w.150000) It was immersed in a 10% water emulsion solution and squeezed dry using a mangle at a squeezing rate of 50%. Two sheets of the adherends obtained as described above were stacked on top of each other and welded under the same conditions as in Example 1. The effects of the present invention are summarized in Table 2.

【table】

Claims (1)

[Claims] 1. After imparting an unsaturated carboxylic acid, its anhydride, or its hydrolyzable functional derivative to a polyamide fiber structure and graft polymerizing it, the carboxyl group in the graft polymer is converted to a group 1 or 2 of the periodic table. 1. An improved method for high-frequency dielectric heating welding of polyamide-based fiber structures, characterized by converting the polyamide-based fibrous structure into a polyamide-based metal salt and subjecting the thus obtained fibrous structure to high-frequency dielectric heating welding.