JPS6358166B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a method for producing a copolymer of an alkylresorcinol and m-substituted phenols. More specifically, it is a method for producing a novolac type copolymer useful as an adhesive between polyester fiber and rubber, etc., via a resol type initial condensate of m-substituted phenols. Polyester fiber has a higher modulus of elasticity than nylon, has excellent dimensional stability, and is less prone to flat spots like nylon, so it is showing superiority over nylon as a tire cord for passenger car tires.However, it has some disadvantages. It also has both. Its biggest disadvantage is that it is difficult to bond due to the structure of polyester itself. In order to solve this problem, many studies have been conducted and reported on adhesives or bonding methods.
Most of them use solvents, in which a highly reactive compound dissolved in a solvent is attached to the fibers and dried, followed by a second stage of similar treatment using resorcinol formalin latex (hereinafter abbreviated as RFL). It is a two-stage process and therefore has disadvantages of solvent hazards, contamination of the working environment, and process complexity. On the other hand, water is used as a medium and adhesive
Japanese Patent Publication No. 11251/1972 and Japanese Patent Publication No. 8733/1986 are known as adhesives and bonding methods that exhibit high adhesive strength by treating RFL in one bath in one step. It goes without saying that one-bath adhesives do not pollute the environment due to flammability or toxicity, and are industrially useful due to the simplified process. Adhesive strength is still insufficient compared to the two-bath type. In Japanese Patent Publication No. 46-11251, in order to obtain a linear polymer, substituted phenols were converted into p--type polymers in which at least two of the 2, 4, and 6 positions remained unsubstituted.
Although the substituted product and the o-substituted product are specified, the reactivity of the copolymer with these alkylresorcins, the ability to form a three-dimensional resin, the adhesive strength, etc. are insufficient.
In JP-A No. 49-37986 (Japanese Patent Publication No. 52-25874), a novolak-type copolymer was obtained by a two-step method in which monovalent phenol and formaldehyde were partially reacted under an acidic catalyst, and then reacted with an alkyl resorcinol. However, in this method, the alkylresorcinol does not always have a structure located on the outside of the molecule, resulting in insufficient adhesive strength. As described above, the performance and effects of alkylresorcin copolymers have been insufficient using conventional techniques. An object of the present invention is to establish a method for producing a polymer that has outstanding effects on adhesion between polyester fibers and rubber. More specifically, the aim is to establish a manufacturing method that can easily provide industrially a polymer that is dispersed in an aqueous medium and that produces sufficient adhesive strength in one bath treatment. The inventors of the present invention took these into account and conducted extensive studies, and found that the above-mentioned alkyl resorcinols can be stabilized as novolac resins, and that they can be further stabilized by co-condensing them with other substituted phenols. It was found that although it is insoluble in water, a stable aqueous dispersion can be obtained by a dispersion method. Alkylresorcin mixtures overcome the disadvantage of being highly reactive and difficult to control the reaction, and can be easily implemented industrially, and the aqueous dispersion of the produced copolymer can be used as a one-bath adhesive for polyester fibers and rubber. As a result, we have established a method for producing a copolymer that currently has the highest level of effectiveness, and have completed the present invention. That is, in the present invention, in the presence of an alkali catalyst, the general formula

[Formula] (in the formula, R ₁ represents a CH ₃ or OCH ₃ group, and R ₂ represents a H or CH ₃ group) and 1.2 for the above phenols.
~2.4 times the molar ratio of formaldehyde is reacted, and unreacted formaldehyde is reduced to 1~30% of the charged amount.
The remaining resol-type initial condensate is obtained, and then an acid equivalent to the alkali catalyst or 10 mol% excess to the phenols, and an alkylresorcin or one thereof at a molar ratio of 1.0 to 2.5 times the phenols. This is a method for producing a water-dispersible alkylresorcin copolymer, which comprises adding the resol initial condensate to a mixture with the above and carrying out a co-condensation reaction. The first feature of the present invention lies in the structure of the monovalent phenols used. It is an m-substituted phenol in which the 2, 4, and 6 positions are all hydrogen, and its substituents have little steric hindrance and high reactivity.
In addition, the copolymer of phenols and alkylresorcin has a structure such that the solubility parameter is close to that of polyester. The phenols used in the present invention include:
Preferred are m-cresol, 3.5xylenol, and m-methoxyphenol. In general, m-substituted phenols are difficult to produce and currently many are expensive, but they are readily available and are fully compatible with the intent of the present invention. The second feature of the present invention is that when obtaining a resol-type initial condensate, the amount of unreacted formaldehyde is 1 to 30%, preferably approximately 2 to 10%, based on the amount charged.
%. The resol-forming reaction conditions are important because they have a great influence on the performance of the final target alkylresorcin copolymer, especially the adhesive performance. Generally, this reaction generates a large amount of heat, and the resol-type initial condensate is unstable to heat. If the reaction is allowed to proceed too much, that is, when unreacted formaldehyde becomes less than 1% of the charged amount, a benzyl ether-type compound is formed due to a dehydration reaction. Undesirable side reaction products such as these are likely to be produced.
On the other hand, if the reaction conditions are too gentle, for example, if the amount of unreacted formaldehyde exceeds 30% of the charged amount, the unreacted formaldehyde will react with alkylresorcin during the novolacification reaction, and the proportion of the novolac copolymer similarly sought will decrease. This results in decreased performance as an adhesive. In order to avoid this, in the method of the present invention, it is necessary to control the reaction so that the amount of unreacted formaldehyde remains within the above specified range. Regarding the reaction temperature, 10° to 90°C, preferably
A range of 25° to 70°C is suitable. Specifically, this temperature needs to be appropriately selected depending on the combination of other conditions, such as the type of phenol used, the amount of catalyst, and the reaction time. Generally, the reaction involves approximately m-cresol, 3,5-
The reaction tends to proceed at lower reaction temperatures in the order of xylenol and m-methoxyphenol. If the amount of catalyst is increased, the reaction temperature can be lowered, and the reaction temperature naturally affects the reaction time, but for process control purposes, the temperature should be adjusted so that it lasts about 1 to 24 hours, preferably about 2 to 10 hours. It is preferable to select. A third feature of the present invention is that the above-mentioned phenols are co-condensed with an alkylresorcinol or a mixture with one or more thereof. In general, alkylresorcinols are more expensive than resorcinols and are difficult to obtain industrially, so they have not been investigated to date. However, recently, an alkylresorcin mixture has been commercially available from Nagoya Yukagaku Kogyo Co., Ltd. under the trade name "Alkylace".
Industrially, it has become cheaper and easier to obtain than resorcinol. "Alkylace" is an alkylresorcin mixture with a boiling point of 270 to 290℃, which is obtained by fractionating and refining a divalent phenol mixture obtained by carbonizing oil shale rock produced in the Soviet Union of Estonia. It is a yellow to reddish brown paste with an average molecular weight of about 140 and a composition of 5-
45-55% methylresorcin, also 5-ethylresorcin, 2,5-dimethylresorcin, 4,5
-75-80 including the three components of dimethylresorcinol
% and a mixture with other alkyl resorcinols. This alkylresorcinol mixture is the above-mentioned "alkylace" purified by fractional distillation.
In addition, it can be used as a crude product, which is more economically desirable. As the alkylresorcin, the aforementioned alkylresorcin mixtures such as alkylace, 3-methylresorcin, 3-ethylresorcin, etc. can be used, and among them, alkylace, which is available at low cost, is preferred. A fourth feature of the present invention resides in a method of condensation reaction between the resol initial condensate and an alkylresorcinol.
Generally, acid and alkylresorcin are added to the resol liquid to perform novolacification, but although this method has the advantage of being able to be done in a single container, the side reaction of novolacification between the initial condensates of the resol due to the addition of acid may occur. Since the resulting condensation reaction proceeds all at once, complicated operations such as gradually increasing the reaction temperature are required for reaction control, and this involves risks. The method of the present invention employs a method in which an alkali catalyst, an equivalent amount or a 10 mol% excess of acid with respect to the phenols used, a mixture of alkylresorcin or one or more thereof, and the above-mentioned resol type initial condensate are gradually reacted. There is a characteristic in the vines. In other words, in the conventional method of suspending a mixture of acid and resorcin in water and adding it to the resol-forming reaction solution, the resol-type initial condensate itself changes until the reaction is completed.
In the method of the present invention, the various problems mentioned above can be solved at once by adding the resol-forming reaction liquid to the mixture. The added resol-type initial condensate can be used after being cooled if necessary, and has the advantage that progress of deterioration over time can be suppressed. The molar ratio of formaldehyde to the phenols used in the present invention is important in order to obtain a copolymer with a preferable molecular weight distribution, and it is preferably used at a molar ratio of 1.2 to 2.4 times the molar ratio of the phenols.
A molar ratio of ~2.2 times is particularly preferred. The molecular weight distribution is measured by gel permeation chromatography (hereinafter referred to as GPC), and based on the waveform and actual adhesive strength, the average molecular weight is in the distribution range of 250 to 1500, preferably 280 to 800. be. The amount of alkylresorcin used in the present invention is preferably 0.8 to 1.2 equivalents per equivalent of methylol group in the resol type initial condensate, and is in the range of 1.0 to 2.5 times the molar ratio of the phenols. Since a considerable portion of the formaldehyde used reacts, the number of methylol groups in the resol initial condensate produced is approximately equal to the number of alkylresorcinols used, making it possible to obtain a copolymer with alkylresorcinols located at the terminals through the condensation reaction. I can do it. Known alkali catalysts can be used, and hydroxides or carbonates of alkali metals or alkaline earth metals are used. The amount of catalyst is in the range of 0.1 to 10 mol%, preferably 0.3 to 5 mol%, based on the phenols. Although the resolization reaction is carried out in an aqueous solvent system, it can also be carried out in a system in which other organic solvents are used in combination. In this case, the raw material phenols are dissolved,
It is also preferable to use a solvent that can also dissolve the generated resol-type initial condensate, examples of which include aliphatic alcohols such as methyl alcohol and ethyl alcohol, and aliphatic ketones such as acetone and methyl ethyl ketone. The acid catalyst used in the cocondensation reaction is equivalent to the alkali catalyst used above or 10 mol% based on the phenols.
It is preferably used in an excess of 0.1 to 3 mol%, but known hydrochloric acid, sulfuric acid, nitric acid, formic acid, oxalic acid, acetic acid, p-
Toluenesulfonic acid etc. can be used. Since the amount of catalyst used remains in the produced resin, it is desirable to use as little as possible. In the cocondensation reaction, a small amount of water is added to suspend the alkylresorcinol, but other solvents may also be used in combination. When using the copolymer produced in this way as an adhesive, it is desirable to remove residual monomers by a known separation method such as distillation or extraction to make a fusible resin, and then make it into an aqueous dispersion. . Thus, the copolymer produced by the method of the present invention has much superior properties in terms of adhesive performance, ease of handling, etc. than those produced by conventionally known methods, and the industrial value of the present invention is high. It is. Adhesive performance is measured by Imperial Chemical Industries Limited (ICI), which is widely used for rubber-polyester fibers as a one-bath adhesive.
It is an aqueous dispersion that is much more stable than Valkabond E manufactured by Co., Ltd., and is also more stable in handling, and is fully suitable for the purpose of the present invention. There is also no problem with storage stability since it is a novolak type resin. The copolymer prepared by the production method of the present invention is most characteristically used in an adhesive treatment solution for polyester fibers. That is, it is used by mixing it with so-called RFL, which is a mixture of an alkaline initial condensate of resorcinol and formaldehyde and rubber latex. As is well known, RFL is generally produced by condensing 1 to 4 moles of formaldehyde to 1 mole of resorcin under an alkali catalyst such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide, and then converting it into vinylpyridine, styrene, or butadiene. - Obtained by mixing one or more of latex, styrene, butadiene latex, polybutadiene latex, natural rubber latex, etc. Each of the two components present in the adhesive treatment liquid has a copolymer solid content of 30 to 50% of the total adhesive solids weight of 100%,
RFL is preferably 50-70. The polyester fibers are immersed in the above-mentioned adhesive treatment solution or coated with adhesive by other suitable means, then heat treated at a temperature in the range of 200°C to 250°C, and the treated cord is embedded in unvulcanized rubber and cured. Adhere with sulfur. Hereinafter, examples will be given to explain the manufacturing method of the present invention, and comparative examples will be given to explain the manufacturing method of the present invention and for comparison.
Further, referring to reference examples, the results of evaluation of adhesive strength using each of the produced copolymers as an adhesive between polyester fiber and rubber will be explained in detail. Furthermore, in the text, parts refer to parts by weight unless otherwise specified. Example 1 While stirring 126 parts of m-cresol with 250 parts of water and 1.6 parts of caustic soda in a 1000 ml four-necked Kolben, 324 parts of a 37% formalin aqueous solution was boiled over 3 hours at a temperature of 50°C. Made and dripped. Stirring was continued for another 2 hours at the same temperature, and when the amount of unreacted formalin reached 10% of the charged amount, the temperature was increased to 25°C.
The reaction was stopped by cooling to . Next, in a 2000 ml separable flask, 580 parts of an alkylresorcin mixture (product name Alkylace abbreviation SAR), 660 parts of water, and 5.8 parts of oxalic acid were charged, and while stirring at 70°C, the above m-cresol-
The formalin reaction solution was slowly added dropwise over 3 hours. After further stirring at the same temperature for 3 hours, the water in the system was removed, and the unreacted m-cresol and alkylresorcin mixture was removed by vacuum distillation. A) 831 copies were obtained. The resin was a reddish-brown solid, a fusible oligomer with a softening point of 120°C, and an average molecular weight of 700. Example 2 216 parts of m-cresol was stirred with 250 parts of water and 1.6 parts of caustic soda in a 1000 ml four-necked Kolben at a temperature of 60°C, and 324 parts of a 37% formalin aqueous solution was slowly prepared over 3 hours. dripped. Stirring was further continued at the same temperature for 2 hours, and when the amount of unreacted formalin reached 5% of the charged amount, the reaction was stopped by cooling to 25°C. Next, in a 2000 ml separable flask, add 508 parts of the alkyl resorcinol mixture, 580 parts of water, and 5.4
of oxalic acid was charged, and the above m-cresol-formalin reaction solution was slowly added dropwise over 3 hours while stirring at 70°C. After further stirring at the same temperature for 3 hours, water in the system was removed, and unreacted m-
The cresol and alkylresorcin mixture were removed by vacuum distillation to obtain 770 parts of m-cresol-alkylresorcin-formadehyde resin (B). Example 3 216 parts of m-cresol was stirred with 250 parts of water and 1.6 parts of caustic soda in a 1000 ml four-necked Kolben at a temperature of 60°C, and 324 parts of a 37% formalin aqueous solution was slowly prepared over 3 hours. dripped. Stirring was further continued at the same temperature for 2 hours, and when the amount of unreacted formalin reached 5% of the charged amount, the reaction was stopped by cooling to 25°C. Next, put 434 parts of 5 into a 2000ml separable flask.
-Add methylresorcin, 500 parts of water, and 5.1 parts of oxalic acid, and add the above m-
The cresol-formalin reaction solution was slowly added dropwise over a period of 3 hours. After further stirring at the same temperature for 3 hours, the water in the system was removed, and unreacted m-cresol and 5-methylresorcin were removed by vacuum distillation. 700 parts of formadehyde resin (C) were obtained. Example 4 244 parts of 3,5- in a 2000 ml four-necked Kolben
While stirring xylenol with 340 parts of water and 4 parts of caustic soda, 324 parts of a 37% formalin aqueous solution was slowly added dropwise at a temperature of 50°C over 3 hours. Stirring was further continued at the same temperature for 1 hour, and when the amount of unreacted formalin reached 5% of the charged amount, the mixture was cooled to 25°C, and 250 parts of ethyl alcohol was added to form a homogeneous liquid, and the reaction was stopped. Next, in a 3000 ml separable flask, add 508 parts of the alkyl resorcinol mixture, 580 parts of water, and 5.4
of oxalic acid was charged, and the above 3,5-xylenol-formalin reaction solution was slowly added dropwise over 3 hours while stirring at 70°C. After further stirring at the same temperature for 3 hours, water and ethyl alcohol in the system were removed, and unreacted 3,5-xylenol and alkylresorcin were removed by vacuum distillation. 798 parts of alkylresorcinol-formadehyde resin (D) were obtained. Example 5 124 parts of m-methoxyphenol were mixed with 250 parts of water and 0.8 parts of caustic soda at a temperature of 30° C. while stirring at 37% of 141.7 parts of m-methoxyphenol in a 500 ml four-necked kolben.
An aqueous formalin solution was slowly added dropwise over 4 hours. Stirring was further continued at the same temperature for 6 hours, and when the amount of unreacted formalin reached 9% of the charged amount, the reaction was stopped by cooling to 10°C. Next, 254 parts of the alkyl resorcinol mixture, 250 parts of water, and 2.8 parts of oxalic acid were placed in a 1000 ml separable flask, and the above mixture was added while stirring at 70°C.
-Methoxyphenol-formalin reaction solution was slowly added dropwise over 3 hours. After further stirring at the same temperature for 3 hours, water in the system was removed, and unreacted m-methoxyphenol and alkylresorcin were removed by vacuum distillation to form m-methoxyphenol-alkylresorcin-formadehyde. 392 parts of resin (E) were obtained. Example 6 108 parts of m-cresol and 122 parts of 3.5-xylenol were mixed with 300 parts of water and 4 parts of caustic soda in a 1000 ml four-necked Kolben with stirring for 60 minutes.
324 parts of a 37% formalin aqueous solution was slowly added dropwise over 3 hours at a temperature of .degree. Stirring was further continued at the same temperature for 1 hour, and when the amount of unreacted formalin reached 5% of the charged amount, the mixture was cooled to 25°C, and 100 parts of ethyl alcohol was added to form a homogeneous liquid, and the reaction was stopped. Next, in a 3000 ml separable flask, add 508 parts of the alkyl resorcinol mixture, 580 parts of water, and 5.4
of oxalic acid and stirred at 70°C.
-Cresol/3.5-xylenol-formalin reaction solution was slowly added dropwise over 3 hours. After further stirring at the same temperature for 3 hours, water and ethyl alcohol in the system were removed, and unreacted m-cresol, 3,5-xylenol, and alkylresorcin were removed by vacuum distillation. -3,5-xylenol-alkylresorcinol-
783 parts of formaldehyde resin (F) were obtained. Comparative Example 1 While stirring 216 parts of m-cresol with 250 parts of water and 1.6 parts of caustic soda in a 1000 ml four-necked Kolben, 324 parts of a 37% formalin aqueous solution was added over 3 hours at a temperature of 35°C. It dripped slowly. Stirring was further continued at the same temperature for 2 hours, and when the amount of unreacted formalin reached 35% of the charged amount, the reaction was stopped by cooling to 20°C. Next, in a 2000 ml separable flask, add 440 parts of alkyl resorcinol mixture (Alkylace), 660 parts
1 part water and 5.8 parts oxalic acid and heated to 70℃.
While stirring, the above m-cresol-formalin reaction solution was slowly added dropwise over 3 hours. After further stirring at the same temperature for 3 hours, the water in the system was removed, and the unreacted m-cresol and alkylresorcin mixture was removed by vacuum distillation.
810 parts of cresol-alkylresorcinol-formaldehyde resin (G) was obtained. Reference Example 1 Using the copolymer resin obtained in the above Examples and Comparative Examples as an adhesive between polyester fiber and rubber,
The adhesive strength evaluation results will be explained below along with the test method. (a) The adhesive treatment liquid was obtained by mixing 40 parts of copolymer aqueous dispersion and 60 parts of RFL. The aqueous copolymer dispersion had a solid content of 15% and was dispersed in water using an anionic surfactant Demol SSL (manufactured by Kao Atlas Co., Ltd.) using a laboratory sand grinder. RFL consists of water, 635.5 resorcinol, 20.5, 37% formaldehyde, 18, 5% caustic soda aqueous solution, 32 vinylpyridine latex (41%), and is an aqueous dispersion with a solid content of 15%. (a) The unvulcanized rubber is a smoked sheet with the following composition: 30 parts styrene-butadiene rubber 70 carbon black 40 stearic acid 1.5 Process oil (petroleum-based) 5 zinc white 5 N-phenyl-β-naphthylamine 1 benzothiazyldis Rufid 0.8 Diphenylguanidine 0.2 Sulfur 2 (C) The polyester fiber tire cord has a polyester fiber of 1500d/2 (the number of twists is 40/2).
10 cm, with a number of first twists of 40/10 cm). (d) Treatment method The polyester fiber tire cord (c) was immersed in the above adhesive treatment solution (a) and heat-treated at 240° C. for 2 minutes at a fixed length. (e) Test method The processing code obtained by the above processing method (d) was buried in the unvulcanized rubber (a) of the above composition and heated at 145°C with 100kg/
Adhesion strength was measured at room temperature by a hot-flow H test under a pressure of cm ² for 30 minutes. (F) The measurement results of adhesive strength are shown in Table 1. It is clear from this table that the adhesive strength of the copolymer produced by the method of the invention is much better than that of the known copolymer (Comparative Example 2). Furthermore, if unreacted formaldehyde, which is out of the scope of the present invention, remains, the adhesive strength is significantly reduced (Comparative Example 1).

【table】

Claims (1)

[Claims] 1. One type of phenol represented by the general formula [Formula] (wherein R ₁ represents a CH ₃ or OCH ₃ group, and R ₂ represents a H or CH ₃ group) in the presence of an alkali catalyst. 1.2 for the above and the above phenols
~2.4 times the molar ratio of formaldehyde is reacted, and unreacted formaldehyde is reduced to 1~30% of the charged amount.
The remaining resol-type initial condensate is obtained, and then an acid equivalent to the alkali catalyst or 10 mol% excess relative to the phenols and an alkylresorcin or one thereof at a molar ratio of 1.0 to 2.5 times relative to the phenols are added. A method for producing a water-dispersible alkyl resorcinol copolymer, which comprises adding the resol initial condensate to a mixture thereof and carrying out a cocondensation reaction.