JPS6224551B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for treating a rubber reinforcing fiber material, and its purpose is to improve the smoothness of a cord or fabric treated with an adhesive, and to produce a rubber reinforcing fiber material having high strength and adhesive strength. It is about providing. Fiber materials such as polyester fibers, nylon fibers, and wholly aromatic polyamide fibers have excellent dimensional stability, heat resistance, and fatigue resistance, and are used as rubber reinforcing materials for belts, tires, and the like. In general, rubber reinforcing materials are made by first twisting a spun fiber bundle (yarn), then collecting two or several yarns and giving them a second twist to form a cord, which is then woven into a sudare fabric or the like, and then treated with an adhesive. Its reinforcing effect is achieved by applying it, embedding it in rubber, and vulcanizing it. Therefore, in order to maximize its effectiveness as a rubber reinforcing material, the adhesive-treated sudare fabric (hereinafter referred to as treated sudare) must not only be highly strong, but also have sufficient adhesive strength with the rubber. Must be. In addition, in recent years, with the aim of streamlining the process, a method of weaving and knitting adhesive-treated cords, embedding them in rubber, and subjecting them to vulcanization heat treatment to form rubber reinforcing materials has become widely used. However, this method is difficult to weave and knit because the treated cord is sticky. Therefore, in addition to the above-mentioned characteristics, from the viewpoint of improving productivity, it is increasingly required that the treated cord be smooth and easy to handle. In order to improve the strength of treated cords and threads, it is necessary not only to stretch the yarn as much as possible to make it as strong as possible, but also to prevent a decrease in strength during the subsequent processes of twisting, weaving, and adhesive treatment. Incidentally, the cause of the decrease in strength at these stages is mainly due to the twisting of the yarns and the adhesive.
It is believed that this is due to the fact that the yarns and single yarns are fixed and the full strength of the initial yarn is not exerted. The number of twists during twisting is determined from the viewpoints of strength, fatigue resistance, etc., depending on the type of rubber product that requires reinforcement, and is determined by the rubber product manufacturer.
On the other hand, the conditions for fixing the single yarns with the adhesive are determined by the issue of how much the adhesive enters inside the cord at the stage of adhering the adhesive, and the subsequent baking conditions. These conditions are determined to be suitable for improving adhesion to rubber in the subsequent vulcanization step and dimensional stability during vulcanization. Sufficient heat must be applied to improve adhesion and reduce heat shrinkage, but on the one hand, such treatments reduce strength, and on the other hand, the tackiness of treated cords has not yet been improved. . As a result of intensive research, the present inventors have discovered that it is possible to obtain treated cords or cords with high adhesiveness, high strength, and smoothness by simply changing the treatment agent for fiber materials.
Surprisingly, the present invention was achieved by discovering that by using specific components, effects previously unimaginable can be achieved. That is, in the present invention, after treating a fiber material with an adhesive containing resorcinol formalin latex,
This is a method for treating a rubber reinforcing fiber material, which is characterized in that it is treated with a treatment agent that is mainly a smoothing agent that is liquid at room temperature and has a molecular weight of 250 to 1200. The fiber materials used in the present invention are fibers of aromatic or linear polyesters containing aromatic or naphthalene rings such as polyethylene terephthalate and polyethylene naphthalate, fibers of aliphatic polyamides such as nylon 6, nylon 6, 6, or polymethaphenylene isophthalate. It means a yarn, cord, or woven fabric made of fibers of wholly aromatic polyamide such as ramid and polyparaphenylene terephthalamide. It goes without saying that the form of the fiber material differs depending on the use, but the treatment of the present invention can be applied to any form of fiber material. For example, a coat may be treated with an adhesive, then woven and knitted, and treated with a treatment agent, or a cord may be sequentially treated with an adhesive and a treatment agent and woven, or the cord may be further treated with an adhesive and a treatment agent. After weaving and knitting, the sag etc. obtained may be sequentially treated with an adhesive and a treatment agent. The resorcinol formalin latex (RFL) used in the adhesive of the present invention is a mixture of rubber latex and an initial condensate obtained by reacting resorcinol-formaldehyde under an alkali or acidic catalyst, and the molar ratio of resorcinol and formaldehyde is 1. A range of /0.1 to 1/8 is used, preferably a range of 1/0.5 to 1/5. More preferably, it is in the range of 1/1 to 1/4. Rubber latex includes butadiene-styrene-vinylpyridine latex (referred to as VP latex), butadiene-styrene latex (referred to as SPR latex), butadiene-vinylpyridine latex, acrylonitrile latex, acrylonitrile-butadiene latex, natural rubber latex, etc. Can be used alone or in combination.
In particular, it is desirable to use VP-latex alone or in a mixed system of VP-latex and other latexes. The mixing ratio of the resorcinol-formaldehyde initial condensate and the rubber latex is 1/1 to 1/15 (weight ratio), preferably 1/3 to 1/12, although it depends on the addition rate of the second component described later. If the proportion of rubber latex is too small, the treated cord becomes hard, and if it is too large, satisfactory adhesion cannot be obtained and the tackiness increases significantly, which is not preferable. Such an adhesive mainly composed of RFL is adjusted to contain 10 to 25% by weight of RFL as a solid content. The adhesive applied to the present invention is made of a composition containing RFL as described above, but if necessary, the adhesive may further contain a polyepoxide compound, an ethylene urea compound, a blocked polyisocyanate, and a water-soluble polyurethane resin. At least one compound selected from the group consisting of: may be contained as a second component. The second component has a ratio of 0.5 to 30 with respect to the above RFL.
It is added in weight percent, preferably 1.0 to 2.0 weight percent.
If the amount of the second component added is too small, good adhesion
Rubber adhesion rate cannot be obtained. On the other hand, if the amount added is too large, the viscosity of the adhesive increases significantly, making it difficult to process the fiber material, and in addition, the adhesive strength and rubber adhesion rate reach saturation, resulting in the effect of increasing the amount of the second component added. The cost will only increase without increasing the
A further disadvantage is that the treated fiber material becomes extremely hard and its strength decreases. The polyepoxide compound contained as a second component in the adhesive of the present invention is a compound containing at least two or more epoxy groups in one molecule in an equivalent amount of 0.2 g or more per 100 g of the compound, such as ethylene glycol, glycerol, sorbitol, pentoxide, etc. Reaction products of polyhydric alcohols such as erythritol and polyethylene glycol and halogen-containing epoxides such as epichlorohydrin, resorcinol, bis(4
-Hydroxyphenyl)dimethylmethane, phenol-formaldehyde resin, resorcinol-formaldehyde resin, and other reaction products of polyhydric phenols and the above-mentioned halogen-containing epoxides, peracetic acid, hydrogen peroxide, etc. to oxidize unsaturated bonds. 3,4-epoxycyclohexene epoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexenecarboxylate, bis(3,4-epoxy-6-methyl-cyclohexylmethyl) adipate, etc. can be mentioned. Among these, reaction products of polyhydric alcohols and epichlorohydrin, ie, polyglycidyl ether compounds of polyhydric alcohols, are particularly preferred because they exhibit excellent performance. Such polyepoxide compounds are usually used as emulsions or solutions. To make an emulsion or solution, for example, such a polyepoxide compound as it is or dissolved in a small amount of a solvent as necessary may be mixed with a known emulsifier such as sodium alkylbenzene sulfonate, dioctyl sulfosuccinate sodium salt, nonylphenol. It is emulsified or dissolved using an ethylene oxide adduct and added to the adhesive. The ethylene urea compound used as the second component in the present invention is represented by the following general formula,
R′ is an aromatic or aliphatic hydrocarbon residue;
n' is an integer from 0 to 2. Typical compounds include aromatic and aliphatic isocyanates such as octadecyl isocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, metaxylylene diisocyanate, diphenylmethane diisocyanate, naphthylene diisocyanate, triphenylmethane triisocyanate, and ethylene. Reaction products with imines are mentioned, and in particular aromatic ethylene urea compounds such as diphenylmethane diethylene urea give good results. In the ethylene urea compound contained in the adhesive as a second component in the present invention, the ethylene imine ring opens and reacts with heating, thereby improving adhesiveness. When such an ethylene urea compound is added to an adhesive and processed, a rubber reinforcing fiber material with excellent adhesion and flexibility can be obtained, and furthermore, as in the case of blocked isocyanate compounds, the blocking component is not liberated upon heating. It does not pollute the environment. Further, the blocked polyisocyanate compound used in combination with the adhesive is an addition compound of a polyisocyanate compound and a blocking agent, and the blocking component is liberated by heating to produce a useful polyisocyanate compound. Examples of the polyisocyanate compound include polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, and triphenylmethane triisocyanate; Examples include polyalkylene glycol adduct polyisocyanates containing terminal NCO groups obtained by reacting compounds having two or more active hydrogen atoms such as methylolpropane and pentaerythritol at a molar ratio of NCO/OH>1. Especially tolylene diisocyanate,
Aromatic polyisocyanates such as meta-xylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate are preferred because they exhibit excellent performance. Examples of blocking agents include phenols such as phenol, thiophenol, cresol and resorcinol, tertiary alcohols such as t-butanol and t-pentanol, diphenylamine,
These include aromatic secondary amines such as xylidine, imides such as phthalic acid imide, lactams such as caprolactam and valerolactam, oximes such as acetoxime, methyl ethyl ketone oxime, and cyclohexane oxime, and acidic sodium sulfite. Such blocked polyisocyanate compounds are particularly formulated with the general formula R″(NHCOX)n″ [R″ is an organic residue selected from the group consisting of aromatic, araliphatic, and aliphatic, and X is a block that is liberated by heat treatment. It is preferable to use a blocked polyisocyanate compound represented by the following formula: where n'' is an integer of 2 or more. In such cases, the adhesive can be prepared by adding a blocked polyisocyanate compound to the RFL liquid and then aging it, or after aging the RFL liquid, adding a blocked polyisocyanate compound immediately before processing the textile material. It can also be used by adding a compound. RFL liquid is usually aged at 15-25℃.
It lasts over 15 hours. Blocked polyisocyanate compounds and
Adhesives containing RFL are typically adjusted to contain 10-25% solids by weight. In this way, in adhesives containing RFL and blocked polyisocyanate compounds, when the compound is heated, the blocking component is liberated and active isocyanate groups are regenerated, reacting with resorcinol and formalin, and significantly increasing the gathering power of RFL. At the same time, it also reacts with the adhesive component attached to the fiber material during the adhesive application process, and further reacts with the rubber during vulcanization, resulting in an overall increase in adhesive strength without curing the fiber material. Furthermore, in the present invention, in addition to RFL, a water-soluble polyurethane resin represented by the following general formula can be contained as a second component as an adhesive, if necessary. [A: organic polyisocyanate residue R: organic residue selected from the group consisting of aromatic, aliphatic, and araliphatic X: blocking agent residue released by heat treatment Y: carbon number 2-6 residue of aminosulfonic acid or aminocarboxylic acid having 1 to 6 carbon atoms n: an integer l of 5 to 30, m: an integer l of 1 to 5 + m: an integer of 2 to 6] The water-soluble polyurethane resin has the general formula The free isocyanate groups of the isocyanate group-containing urethane prepolymer containing 10 to 50% by weight of polyoxyethylene groups (-CH ₂ CH ₂ O-) as hydrophilic groups were blocked with a blocking agent as shown in Blocked isocyanate (RXCONH-) and at least one hydrogen atom reactive with the isocyanate group and at least one anion-forming group.
(YCONH)
−). To be more specific, polyoxyethylene group (-
CH ₂ CH ₂ O−) _o is an essential component in order for the obtained polyurethane resin to have stable water solubility, and its n
The number is 5 to 30, which is approximately 200 to 1300 in terms of the molecular weight of polyethylene glycol. Further, the organic polyisocyanate residue A targets organic polyisocyanates having a functional number of 3 to 7, such as triphenylmethane triisocyanate,
Polymethylene polyphenyl isocyanate as well as hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate,
Examples include polyisocyanates obtained by reacting tolylene diisocyanate, diphenylmethane diisocyanate, etc. with low molecular weight polyols such as trimethylolpropane, trimers of hexamethylene diisocyanate, and the like. Also blocked isocyanate (RXCONH−) _l
is an addition compound of the above-mentioned isocyanate group and a blocking agent, and the blocking component is liberated by heating to produce an active polyisocyanate compound. Examples of blocking agents include phenols such as phenol, thiophenol, cresol, and resorcinol, t-butanol, and t-butanol.
Tertiary alcohols such as pentanol, aromatic secondary amines such as diphenylamine and xylidine, imides such as phthalic acid imide, lactams such as caprolactam and valerolactam, oximes such as acetoxime, methyl ethyl ketone oxime, and cyclohexane oxime. and acidic sodium sulfite, among which alkylphenols such as phenol, cresol, and nonylphenol are particularly preferred. That is, blocked isocyanate (-
RXCONH−) _l is preferably

[Formula] (R is an alkyl group having 1 to 9 carbon atoms or a hydrogen atom) can be mentioned. Furthermore, as mentioned above, examples of compounds containing at least one hydrogen atom reactive with an isocyanate group and at least one anion-forming group include aminosulfonic acids having 2 to 6 carbon atoms, such as taurine, N
-methyltaurine or N-butyltaurine, or aminocarboxylic acids having 1 to 6 carbon atoms, such as glycine or alanine. In this case, l + m is the value obtained by subtracting 1 from the functional number of 3 to 7 of the organic polyisocyanate, so it is 2 to 6, and m is required to be at least 1 to ensure the water solubility of the polyurethane resin obtained, so l
is 5 or less, and l and m are each from 1 to 5. In the case of adhesives containing water-soluble polyurethane resin, since the polyurethane resin is water-soluble, it is uniformly mixed with RFL, and the adhesive solution has good stability over time and process stability, and is suitable for tire coating. and has excellent adhesion to rubber. Then, through heat treatment in the post-process, it reacts strongly with the RF resin and even the rubber latex, creating an even stronger interaction. Furthermore, by heat treatment, the isocyanate compound dissociated from the polyurethane pre-resin self-polymerizes, significantly increasing the cohesive force of the adhesive layer, and interacting with the rubber component, dramatically increasing the adhesive force and rubber adhesion rate. improve. Next, in the present invention, after applying the adhesive to the fiber material, the fiber material is treated with a treatment agent mainly composed of a smoothing agent having a molecular weight of 250 to 1,200, which is liquid at room temperature, and preferably having a molecular weight of 300 to 1,000. Such a treatment is a necessary component in order to improve the adhesion of the resulting rubber reinforcing fiber material to rubber and to ensure the smoothness of the material. The "room-temperature liquid leveling agent with a molecular weight of 250 to 1200" used in the present invention is a hydrophobic molecular weight of 250 to 1200.
1200 is an organic compound that is liquid at room temperature. Liquid at room temperature means that it is liquid at a normal operating temperature of 18 to 25°C, and is a component that has been conventionally used to improve the lubricity of textiles and machinery. For example, esters of monohydric alcohols of monobasic acids such as methyl oleate, butyl stearate, oleyl oleate, isostearyl palmitate, isostearyl oleate, etc.
Monohydric alcohol esters of dibasic acids include dioleyl adipate, dioctyl acelate, ditridecyl sebacate, and dioleyl dithiopropionate; monohydric alcohol esters of tribasic acids include tridecyl tourmelitate and trioleyl trimelli. As fatty acid esters of dihydric alcohols such as tate, neopentyl glycol diolate, 1.6 hexanediol diolate, 4.
4' Isopropylidene bisphenoxyethyl laurate, etc., glycerin triolate, pentaerythritol tetraoleate, etc. as a whole fatty acid ester of a polyhydric alcohol, etc. Other polyesters of a dihydric alcohol and a dibasic acid are connected at the end with a monohydric alcohol or a monobasic acid. Examples include those whose molecular weight is reduced to 1200 or less by blocking with acid, and urethane made from diphenylmethane diisocyanate and oleyl alcohol. Furthermore, if the individual components have a molecular weight of 250 to 1200, the smoothing agent mixture obtained by mixing them can also be
If this mixture itself is liquid at room temperature, it can be used as a component of the present invention. For example, oleyl oleate containing a small amount of oleyl stearate or stearyl oleate generated by partial hydrogenation of oleyl oleate can be used as long as they are compatible and liquid at room temperature. The smoothing agent used in the present invention must be liquid at room temperature and have a molecular weight of 250 or more and 1200 or less. If this smoothing agent becomes a solid at room temperature, it will become water repellent and its adhesion will decrease, and if its molecular weight is less than 250 or
When it exceeds 1200, smoothness decreases. Such a processing agent is mainly composed of a smoothing agent, but in order to further exhibit the effects of the present invention, it is preferable to increase the blending ratio of the smoothing agent to 70% by weight or more. The treatment agent applied after the adhesive treatment in the present invention can be dissolved in an organic solvent such as trichlene or percrene, or can be applied in the form of an aqueous emulsion.
In order to increase the leveling agent ratio, it is preferable to apply it straight. Any method can be used to attach the adhesive and treatment agent to the fiber material, such as adhesion with a roller, application by spraying from a nozzle, or immersion in a liquid bath. The amount of solid content attached to the fiber material is 0.5 to 10% by weight, preferably 1 to 5% by weight as an adhesive.
As a treatment agent, it is 0.05 to 5% by weight, preferably 0.1
It is preferred that the amount is 3 to 3% by weight. In order to control the amount of solid content attached to the fiber material, means such as squeezing with a pressure roller, scraping with a scraper, blowing off with air, suction, absorption, and beating with a heater may be used. Next, a treatment agent mainly composed of a smoothing agent is applied.If it is straight, it can be used as is, but if it is applied as an aqueous emulsion solution, it can be applied at a temperature above the boiling point of the water or solvent, for example, in the case of an aqueous emulsion105 It is sufficient to dry at ~120℃. The fiber material treated in this way has general properties such as excellent tensile strength and dimensional stability for rubber reinforcement, and is especially smooth, has good moldability, and has excellent fatigue resistance. Furthermore, the rubber adhesion rate of the fiber material after vulcanization by embedding in compounded rubber is high, and it exhibits extremely high adhesive strength. Although it is not clear why the present invention allows smooth and highly adhesive treated fiber materials to be obtained, the smoothing agent coats the adhesive layer, resulting in improved rubber reinforcing fiber materials such as treated cords and sag. The smoothness is significantly increased, and on the other hand, the smoothing agent on the RFL (adhesive) swells the RFL itself and makes it solubilized to some extent, and also swells the unvulcanized rubber that is the adherend, improving wetting of both. It is presumed that it has a solubilizing function. The present invention will be explained in more detail below with reference to Examples. In the examples, percentages are given on a weight basis. In addition, in the examples, the inter-ply peel force indicates the adhesive force between the fiber material and the rubber, and 2 ply treated cords were made into a cross ply (cord density 27endo/25 cm) at a 90 degree angle for automobile tires. After embedding the carcass in compound rubber and vulcanizing it by pressing at 160℃ for 20 minutes, both plies were separated at 200m/m1.
The force required to peel it off at a pulling speed of 1 kg/3 cm
It is expressed as In addition, the rubber adhesion rate is a measure that indicates the adhesion of rubber to fiber materials, and when measuring the above-mentioned positive peel force, the cord that has been peeled off from the rubber is observed with the naked eye, and the middle part of the cord surface where the rubber is attached is determined. is expressed as a percentage. The bending hardness of the cord is measured using the Gurley method, and the higher the measured value, the harder it is. Furthermore, the strength retention rate is a measure of the degree of fatigue resistance, and measures how much strength remains after the cord is subjected to repeated fatigue of 6% elongation and 18% compression 3.5 million times using a Kutsdritsu fatigue testing machine between rotating disks. It is expressed as a percentage. The smoothness of the treated cord is 60m/mφ in diameter, and the roughness is
When winding at 2 m/min while contacting a 3S matte finish pin at a contact angle of 180°, the tension at the entrance to the pin (T ₁ )
Then, the exit tension (T ₂ ) is measured, and the frictional force (F) is calculated as F=T ₂ -T _1. It is judged that the smaller F is, the better the smoothness is. Example 1 Add 10g of a 10% aqueous sodium hydroxide solution and 30g of a 28% aqueous ammonia solution to 260g of water, stir well, and add 60g of a resorcin-formaldehyde initial condensate (40% acetone solution) that has been condensed in advance with an acidic catalyst into this aqueous solution. Add and disperse thoroughly. Next, Hycar2518FS (40% manufactured by Nippon Zeon Co., Ltd.)
Dispersion Vp Latex) 240gr Hycar LX−112
Add 100 gr of (40% dispersion SBR latex manufactured by Nippon Zeon Co., Ltd.) and 80 gr of diphenylmethane diethylene urea aqueous dispersion (25% dispersion) to 200 gr of H ₂ O, add while stirring thoroughly, and add formaldehyde ( 37%) 20gr was added to obtain an aqueous adhesive solution. Next, ethylene glycol diglycidyl ether and a 10 mole adduct of laurylamine ethylene oxide at a concentration of 10% by weight to the ethylene glycol diglycidyl ether were added in advance. The mixture was mixed and dispersed, and the ethylene glycol siglycidyl ether was attached to the melt-spun polyethylene terephthalate fiber so that the amount of adhesion was 0.5% by weight, and after stretching, it was heat-treated at 200°C for 1000 de//
A drawn yarn of 250fil was obtained. Three of the obtained epoxy-treated polyethylene terephthalate drawn yarns were twisted together (number of twists 40×40T/
A 10 cm) cord was passed through the adhesive solution by immersion using a computer treater processing machine (tire cord processing machine manufactured by CA Ritzler), then dried at 100°C for 120 seconds, and then heat treated at 230°C for 120 seconds. The treated cords were further treated with various smoothing agents shown in Table 1 (the emulsion or solution of the smoothing agent was dried at 110°C for 120 seconds). After embedding it in unvulcanized rubber with a carcass composition mainly composed of rubber and vulcanizing it at 150°C for 30 minutes, the inter-ply peeling force and rubber adhesion rate were measured.The results are summarized in Table 1. As is clear from Table 1, the molecular weight is 250 to 1200.
It can be seen that the cord treated with the smoothing agent has improved stiffness and rubber attachment.

[Table] Example 2 Add 4g of 10% caustic soda aqueous solution to 63g of water and stir. Next, add 12.5g of resorcin and dissolve. Further, formalin (37%) is added and aged at 25°C for 3 hours. After aging, add a caustic soda solution to 443.5gr of water in advance.
3.0gr, Nipole 2518FS (40 manufactured by Nippon Zeon Co., Ltd.)
%) 293gr Nipole LX-112 (Nippon Zeon Co., Ltd.)
An aqueous solution of an aged resorcinol formaldehyde initial condensate was slowly added to the solution prepared by adding 126 gr of 40% of the product, and the mixture was aged at 25°C for 16 hours to obtain an aqueous adhesive solution. Nylon 6 tire cord (1260/238×38T/
10cm) in the adhesive and dried at 100℃ for 120 seconds.
Heat treatment was performed at 200°C for 120 seconds. Then, it was treated with the treatment agent shown in Table 1 above. The results are shown in Table 3. It can be seen that, similar to polyester, polyamide fiber also has improved rubber adhesion and smoothness.

【table】

Claims (1)

[Claims] 1. After treating a fiber material with an adhesive containing resorcinol, formalin, and latex,
1200 A method for processing fiber materials for rubber reinforcement, characterized by processing with a processing agent mainly consisting of a smoothing agent that is liquid at room temperature. 2. The method for treating a rubber reinforcing fiber material according to claim 1, wherein the fiber material is made of polyester fiber, aliphatic polyamide or wholly aromatic polyamide fiber. 3. The method for treating a rubber reinforcing fiber material according to claim 1 or 2, wherein the smoothing agent has a molecular weight of 300 to 1000. 4. The method for treating a rubber reinforcing fiber material according to claim 1, 2 or 3, wherein the treatment agent contains 70% by weight or more of a smoothing agent.