JPS6278274A - Method for adhesive treatment of polyamide synthetic fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for treating polyamide synthetic fibers with an adhesive, and in particular, a method for treating polyamide synthetic fibers with an aqueous solution made of resorcinol-holimarin condensed metal. The present invention relates to an adhesive treatment method in which the adhesive is immersed in a liquid adhesive and then heat-treated.

(Prior art) Polyamide fibers that reinforce rubber molded products such as tires, conveyor belts, and hoses are produced by heating or twisting 500 to 3,000 denier yarns consisting of 100 to 500 filaments or twisting 2 to 3 filaments together. After making it into a code,
In order to improve adhesion to rubber, a method of immersing the material in an aqueous solution of resorcinol formalin latex (RFL) and heat treating it is widely used. However, when implementing these methods, cords treated with adhesive tend to become stiff due to penetration of the adhesive into the cord, solidification, and an increase in the packing density of the constituent filaments due to tension during heat treatment. Such an increase in hardness causes local stress concentration, which not only reduces strength and fatigue resistance, but also has a significant negative effect on workability in the process of molding tires and the like.

Various methods have been proposed to improve the flexibility and strength retention of polyamide fibers treated with adhesives as described above. For example, polyamide fibers are immersed in a specific urethane resin solution, dried under dry heat, and then RF
Adhesive treatment method of immersing in LF solution and heat treatment (Japanese Patent Application Laid-open No. 5
8-81686) or after applying a water-based emulsion oil to undrawn yarn of polyamide fibers that have been spun and cooled, the yarn is passed through an interlacer to generate uneven streaks on the surface of the yarn and is used for strong use after dipping. A method (see Japanese Unexamined Patent Publication No. 15052/1983) has been proposed to improve the ratio. Although the above-mentioned proposed treatment methods have improved flexibility or strength retention to some extent, the current situation is that they have not yet reached a satisfactory level.

(Problems to be solved by the invention) In recent years, there has been a demand for lighter tires and longer running life.
Furthermore, with the increase in denier for process improvements, improvements in the moldability of green tires have come to be desired, and improvements in the strength, flexibility, and fatigue resistance of treated cords are particularly important for tire cords. It became so. However, the processing method proposed above requires a complicated process, and the performance described above is not sufficient.On the other hand, the resorcinol-formalin composite, which has been commonly used in the adhesive treatment of polyamide fibers, is condensed under an alkali catalyst. In this case, the methylolation rate is faster than the condensation reaction rate, forming a condensate in which methylolation has preferentially progressed.
When polyamide fibers are impregnated and heat treated, a resin film with a high crosslink density is formed, and the resulting fibers have low flexibility and do not meet the above requirements in terms of strength and fatigue resistance.

(Means for Solving the Problems) This invention provides polyamide synthetic fibers with resorcinol (R
) and formalin (F) at a molar ratio (R/F) of 110.
A water-soluble non-thermosetting resorcinol/formalin composite is acidic condensed by blending in a ratio of 5 to 1/l, and the total amount of formalin is 0.9 to 1.6 mol per 1 mol of the resorcinol component of the condensate. A polyamide-based synthetic fiber characterized by being immersed in an aqueous solution of an adhesive consisting of Holimarin added as above, caustic soda to adjust the pH to at least 7.0, rubber latex, and ammonia, and then heat-treated. This is an adhesive treatment method.

The above-mentioned resorcin-formalin composite (referred to as RF condensation alloy) is a product obtained by acidic condensation of resorcin (R) and formalin (F) at a molar ratio (R/F) of 110.5 to 1/1. RF condensation alloy 1, for example, R/F is 11
0.6 product name Penacolite R-2170 (
(manufactured by Kotspurs Co., Ltd.) and the product name Sumika Lure 00 (manufactured by Sumima Kagaku Kogyo Co., Ltd.), and a product with an R/F of 1/1 under the trade name Adno)-RF (manufactured by Hodogaya Chemical Co., Ltd.) are commercially available. . The RFF compound blended into the RFLF adhesive conventionally used to treat polyamide synthetic fibers is R/
Although F is condensed in an amount of 1/1 to 1/3 under an alkaline catalyst such as caustic soda, this RF condensation alloy does not provide the desired flexibility, strength, and fatigue resistance of the cord.

Formalin added to the above RFF compound has a total formalin amount of 0.9 to 1 mole of resorcin in the RFF compound.
It is blended in an amount of 1.6 mol, preferably 1.0 to 1.4 mol. If the total polymarine content is less than 0.9 mol, the flexibility will be improved and the cord strength will be high, but the cohesive force will be low and high adhesion strength will not be obtained;
If the amount exceeds molar, the flexibility and fatigue resistance will not be improved, and the strength and fatigue resistance will also decrease. Also, the R/F of the RFF compound is 1
Even if it is /1, high adhesive strength cannot be obtained if Holimarin is not added.

The latex may be one or a mixture of two or more latexes such as natural rubber, styrene-butadiene copolymer rubber, and styrene-butadiene-vinylpyridine copolymer.

Caustic soda is added to facilitate the solubility of the RF condensation alloy in water. Also, ammonia is RFLF
It ensures the storage stability (particularly gelation prevention) of the adhesive, and the P) of the RFLF adhesive is adjusted to 7.0 or more, preferably 9.0 or more, and more preferably 10.0 or more. .

The mixing ratio with the RF condensation alloy latex is preferably 174 to 178. The RFLF adhesive is used as an aqueous solution, and its solid content concentration is preferably 10 to 30% by weight.

The polyamide synthetic fiber of the present invention is a filament yarn obtained by melt-spinning and drawing polyamide such as nylon 6, nylon 66, or nylon 46, or a filament yarn obtained by twisting one or more filament yarns. .

The polyamide fiber may contain a heat stabilizer, an antioxidant, an antistatic agent, an adhesion improver, etc., if necessary.

The polyamide synthetic fiber is immersed in the RFL adhesive aqueous solution and then heat-treated to adhere RFL. The amount of solids attached to the polyamide cord is preferably 3 to 10% by weight.

(Function) Since the RF metal condensate used in this invention is prepared using an acid such as sulfuric acid as a catalyst, the condensation reaction rate of the resulting RF metal condensate is faster than the methylolization rate.
This results in a two-dimensionally condensed substantially thermoplastic resin. When a polyamide synthetic fiber is impregnated with an RFL adhesive liquid prepared by blending formalin and latex added in a strictly specified manner to this resin and heat-treated, RFL
Although the resin forms a two-dimensional network on the fibers, the added polymarin restricts the crosslinking density to the minimum necessary limit, making it flexible and forming a resin film with high cohesion, making the treated fibers flexible. This results in a significant improvement in strength and fatigue resistance.

(Example) % and parts in each example are expressed on a weight basis unless otherwise specified.

Example I RF metal shrinkage product (R/F = 110.6.75% aqueous solution, trade name Penacolite R-2170) 33.8 parts, 3
After mixing an arbitrary amount of 7% formalin, 3.47 parts of 20% caustic soda, and 406 parts of water and aging at 20°C for 6 hours,
This is combined with 41% styrene/butadiene/vinylpyridine copolymer rubber latex (trade name: Viratex).

Resident Naugatuck Co. I [) 310.9 parts, 49% styrene-butadiene copolymer rubber latex (product name J904)
9, Manufactured by Naugatuck Co., Ltd.) 86.8 parts, 17.4 parts of 28% ammonia water and water were added to make R with a solid content of 20%.
A FL adhesive treatment solution was prepared. After immersing nylon 6 tire cord (1890 denier/2 strands) in this treatment solution, the amount of solid content applied was 5% compared to the untreated tire cord.
%, and then heated at 120°C for 2 minutes, 1.
Hot air drying was performed under 5% tension. Next, the cord was subjected to 8.5% tension for 60 seconds in heated air at 200°C, and then heat-treated for 60 seconds in heated air at 200°C under a fixed length to obtain an adhesive-treated cord.

Example 2 In Example 1 above, an RF condensate (R/F=1/1.
An adhesive treated cord was obtained in the same manner as in Example 1, except that a 43% aqueous solution (trade name: Atvar RF) was used.

Comparative Example 18.75 parts of Lusorcin - 27.65 parts of 37% Folymarin (R/F=1/2), 2.55 parts of 20% caustic soda
and 404.5 parts of water were mixed and aged at 20°C for 6 hours to produce a resol type RF initial condensate, which was then mixed with 41% styrene/vinylpyridine copolymer rubber latex (311.0 parts).
86.7 parts of 49% styrene/butadiene copolymer rubber latex, 17.4 parts of 28% ammonia water, and water to prepare an RFL adhesive treatment solution with a solid content of 20%.
Using this treatment liquid, a nylon 6 tire cord was treated in the same manner as in Example 1 to obtain an adhesive-treated cord.

Comparative Example 2 An adhesive-treated cord was obtained in the same manner as in Comparative Example 1 except that R/F=1/1.4.

The results of measuring the physical properties of the treated cords of each of the above Examples and Comparative Examples are shown in the table below.

In addition, among the physical properties, the bending hardness measure that represents the cord flexibility is measured using the Gurley method, that is, the Gurley States Funestester (
This is the value obtained by determining the swing width of a pendulum (load: 25 g) using a pendulum (manufactured by Toyo Seiki Co., Ltd.) when the length of the sample was 3.8 an.

The adhesive strength is the value (kg/cm) determined by the H test method. That is, using a normal tube fatigue tester, a tube fatigue test piece was prepared in which dip cords were embedded at a density of 25 cords/2.54 CIl, at a bending angle of 85 degrees and an internal pressure of 3.5 kg/a1. The tube was fatigued at a rotational speed of 860 rpm, and the time until the tube broke was measured.

As shown in the table above, Example 1 a, in which the molar ratio of total formalin to 1 mole of resorcinol component was less than 0.9 mol, had poor adhesive strength and fatigue resistance, and the molar ratio of total formalin to 1.9 mol was poor. f of Example 1 greater than 6 and Example 2
No. e has high bending hardness and poor fatigue resistance. Further, even if the molar ratio of total formalin is greater than 0.9 mol, Example 2 (a) in which formalin is not added has poor adhesive strength and fatigue resistance.

Furthermore, Comparative Example 1°2, in which the RF condensate had an R/F of 1/2 or 1/1.4, had high bending hardness, significantly poor fatigue resistance, and low strength.

(Effects of the Invention) The polyamide synthetic fiber according to the present invention has low bending hardness and excellent flexibility, does not reduce adhesive strength with rubber, and has excellent fatigue resistance. As a result, it is advantageous in the production process of rubber moldings as a reinforcing material.

Patent applicant: Toyobo Co., Ltd. Agent: Patent Attorney Takeo Sakano Yoshi 1) Tsukasa Tsukasa

Claims (1)

[Scope of Claims] [1] Polyamide-based synthetic fiber is made of resorcinol (R) and formalin (F) at a molar ratio (R/F) of 1/0.5 to 1.
A water-soluble non-thermosetting resorcinol/formalin condensate that was acidicly condensed by blending with /1 and resorcinol component 1 of the condensate.
Holimarin added such that the total amount of Holimarin is 0.9 to 1.6 mol based on mol, and the pH is at least 7.
．． An adhesive treatment method for polyamide synthetic fibers, which comprises immersing polyamide synthetic fibers in an aqueous adhesive solution consisting of caustic soda, rubber latex, and ammonia to make the fibers zero, and then heat-treating the fibers.