JP2022055073A - Adhesive composition for rubber reinforcement fiber - Google Patents

Abstract

To provide an adhesive composition for a rubber reinforcement fiber that is excellent in storage stability and contains a resol type resorcinol-formaldehyde resin.SOLUTION: An adhesive composition for a rubber reinforcement fiber contains a resol type resorcinol-formaldehyde resin, and a rubber latex, in which the resol type resorcinol-formaldehyde resin is a reactant obtained by reacting a bisphenol compound with 1-4 mol of formaldehyde with respect to 1 mol of the bisphenol compound in the presence of an alkali catalyst, and a reactant obtained by reacting resorcinol with 0.7-3 mol of formaldehyde with respect to 1 mol of the resorcinol in the presence of the alkali catalyst, and a ratio of the bisphenol compound to the total mass of the bisphenol compound and the resorcinol is 10-90 mass%.SELECTED DRAWING: None

Description

The present invention relates to an adhesive composition for rubber reinforcing fibers.

Composite materials made of rubber and fibers (hereinafter, also referred to as "rubber-based composite materials") are used for various rubber products such as tires, belts, and hoses. As the fiber of the rubber-based composite material (hereinafter, also referred to as "rubber reinforcing fiber"), polyamide fiber, polyester fiber, aramid fiber, steel fiber, glass fiber, carbon fiber and the like are used.

In a rubber-based composite material, an adhesive may be used to bond the rubber and the rubber reinforcing fiber.
As an adhesive for adhering rubber and rubber reinforcing fibers, a mixture of resorcinol-formaldehyde resin (hereinafter, also referred to as "RF resin") and rubber latex is used as a main component because a good bonding force can be obtained. Adhesives for formaldehyde, so-called RFL adhesives, are widely used. The RFL adhesive is prepared by mixing an aqueous solution of resorcinol and formaldehyde (formalin) and reacting in the presence of an alkaline catalyst such as sodium hydroxide to prepare a reaction solution containing an RF resin (hereinafter, also referred to as “RF solution”). It is produced by adding and mixing rubber latex to the RF solution.

Further, in Patent Document 1, a solution obtained by dispersing a resol-type bisphenol-formaldehyde resin or a novolak-type bisphenol-resorcinol-formaldehyde resin in an alkaline aqueous solution, a resorcinol-formaldehyde initial condensate, and a rubber latex are contained in a specific ratio. A method of adhering rubber and aromatic polyamide fibers using a mixed aqueous adhesive is described.

Special Publication No. 54-1355

However, conventionally, the RF resin used for the RFL adhesive has a problem of high reactivity and low storage stability. For example, even if the RF liquid is left at room temperature for about 24 hours, gelation occurs and it becomes unusable. Therefore, at the time of manufacturing tires and the like, there continues to be a situation in which an RF liquid must be prepared as described above, and a rubber latex is added and mixed with the RF liquid to manufacture and use an RFL adhesive. Since harmful formaldehyde is used in the preparation of RF liquid, sufficient environmental measures are required, and if the measures are insufficient, the working environment will be significantly deteriorated.

Since the aqueous solution type adhesive described in Patent Document 1 also uses a resorcinol-formaldehyde initial condensate, it has the same problems as the RFL adhesive.
Since the novolak type bisphenol-resorcinol-formaldehyde resin described in Patent Document 1 is a novolak type, the storage stability is relatively good. However, when the resorcinol-formaldehyde initial condensate is not blended, it is necessary to add a cross-linking agent separately, which is not preferable in terms of cost.

An object of the present invention is to provide an adhesive composition for rubber reinforcing fibers containing a resol type RF resin having excellent storage stability.

The present invention has the following aspects.
[1] Resorcinol-formaldehyde resin and rubber latex are included.
The resol-type resorcinol-formaldehyde resin is a reaction product obtained by reacting a bisphenol compound with 1 to 4 mol of formaldehyde with respect to 1 mol of the bisphenol compound in the presence of an alkaline catalyst, and with respect to resorcinol and 1 mol of the resorcinol. It is a reaction product obtained by reacting 0.7 to 3 mol of formaldehyde in the presence of an alkaline catalyst, and the ratio of the bisphenol compound to the total mass of the bisphenol compound and the resorcinol is 10 to 90% by mass. Adhesive composition for rubber reinforcing fibers.
[2] Resorcinol-formaldehyde resin and rubber latex are included.
The resol-type resorcinol-formaldehyde resin has a total molar amount of bisphenol compound, resorcinol, 1 mol with respect to 1 mol of the bisphenol compound, and 0.7 mol with respect to 1 mol of the resorcinol, or 1 mol of the bisphenol compound. It is a reaction product obtained by reacting 4 mol of formaldehyde with 3 mol of the total amount of formaldehyde with respect to 1 mol of the resorcinol in the presence of an alkaline catalyst, with respect to the total mass of the bisphenol compound and the resorcinol. An adhesive composition for rubber reinforcing fibers, wherein the proportion of the bisphenol compound is 10 to 90% by mass.
[3] The adhesive composition for rubber reinforcing fibers according to the above [1] or [2], wherein the bisphenol compound contains bisphenol F.

According to the present invention, it is possible to provide an adhesive composition for rubber reinforcing fibers containing a resol type RF resin having excellent storage stability.

The figure explaining the measuring method of the tensile breaking strength.

Hereinafter, embodiments of the present invention will be described in detail schematically. However, the description in the following embodiments is merely an example, and is not intended to limit the technical scope of the present invention to those alone.

[First Embodiment]
The adhesive composition for rubber reinforcing fibers according to the first embodiment of the present invention (hereinafter, also referred to as “adhesive composition (1)”) is a specific resol-type resorcinol-formaldehyde resin (hereinafter, “resole-type RF”). Also referred to as "resin (1)") and rubber latex.
The adhesive composition (1) may further contain components other than the resole-type RF resin (1) and the rubber latex, if necessary, as long as the effects of the present invention are not impaired.

<Resol type RF resin (1)>
The resole-type RF resin (1) is a reaction product obtained by reacting a bisphenol compound and 1 to 4 mol of formaldehyde with 1 mol of the bisphenol compound in the presence of an alkaline catalyst (hereinafter, also referred to as "BF reactant"). It is a reaction product obtained by reacting resorcinol and 0.7 to 3 mol of formaldehyde with respect to 1 mol of resorcinol in the presence of an alkaline catalyst, and the ratio of the bisphenol compound to the total mass of the bisphenol compound and resorcinol is 10. It is ~ 90% by mass.

The bisphenol compound is a compound having two hydroxyphenyl groups. Many bisphenol compounds have diphenylmethane as the basic skeleton.
Examples of the bisphenol compound include bisphenol A, bisphenol F, bisphenol AF, bisphenol B, bisphenol C, bisphenol E, bisphenol S, bisphenol Z and the like. One of these bisphenol compounds may be used alone, or two or more thereof may be used in combination.

As the bisphenol compound, bisphenol F, that is, bis (4-hydroxyphenyl) methane is preferable. By using bisphenol F, the wettability of the rubber reinforcing fiber of the adhesive composition (1), particularly the polyamide fiber, to the surface is improved. Bisphenol F may be used in combination with other bisphenol compounds.
The ratio of bisphenol F to 100 mol% of all bisphenol compounds is preferably 10 mol% or more, more preferably 50 mol% or more, and may be 100 mol%.

Resorcinol is a benzenediol having a structure having two hydroxy groups at the meta position of the benzene ring, and is a positional isomer of catechol or hydroquinone. Resorcinol is also referred to as 1,3-dihydroxybenzene.

Formaldehyde is the simplest aldehyde and is referred to as metanal in the IUPAC nomenclature.
Formaldehyde is usually used in the form of an aqueous solution. The formaldehyde concentration in the formaldehyde aqueous solution is, for example, 30 to 60% by mass.

The ratio of the bisphenol compound to the total mass of the bisphenol compound and resorcinol is 10 to 90% by mass, preferably 20 to 70% by mass, and more preferably 30 to 50% by mass. When the proportion of the bisphenol compound is 10% by mass or more, the storage stability of the resole-type RF resin (1) and the storage stability of the adhesive composition (1) are excellent. When the proportion of the bisphenol compound is 90% by mass or less, the adhesiveness between the rubber and the rubber reinforcing fiber is good.

The resol type RF resin (1) is produced through the following steps A and B.
Step A: A step of reacting a bisphenol compound with 1 to 4 mol of formaldehyde with 1 mol of the bisphenol compound in the presence of an alkaline catalyst.
Step B: A step of reacting the reactant (BF reactant) produced in Step A with resorcinol and 0.7 to 3 mol of formaldehyde with respect to 1 mol of resorcinol in the presence of an alkaline catalyst.

In step A, when the bisphenol compound and formaldehyde are reacted in the presence of an alkaline catalyst, a reaction (methylolation reaction) in which a methylol group is added to the benzene ring of the bisphenol compound occurs. Subsequently, in step B, when resorcinol and formaldehyde are reacted in the presence of an alkaline catalyst, a reaction (methylolation reaction) in which a methylol group is added to the benzene ring of resorcinol occurs. After that, the condensation reaction proceeds between the methylol group adduct of the bisphenol compound and the methylol group adduct of resorcinol.

In step A, the amount of formaldehyde used is 1 to 4 mol, preferably 2 to 3 mol, per 1 mol of the bisphenol compound. When the amount of formaldehyde used is at least the above lower limit value, the adhesiveness between the rubber and the rubber reinforcing fiber is excellent, and when it is at least the above upper limit value, a large amount of unreacted formaldehyde does not remain in step A and thereafter. In step B, the step of mixing with rubber latex, etc., the volatilization of formaldehyde in the working environment atmosphere can be suppressed.

The alkaline catalyst is not particularly limited as long as it can promote the reaction between the bisphenol compound or resorcinol and formaldehyde, and various alkaline substances can be used. Specific examples include hydroxides of alkali metals such as sodium and potassium (sodium hydroxide, potassium hydroxide, etc.) and hydroxides of alkaline earth metals such as calcium, magnesium and barium (calcium hydroxide, magnesium hydroxide). , Barium hydroxide, etc.), Inorganic alkaline substances such as sodium carbonate, ammonia; Tertiary amines such as triethylamine, trimethylamine, triethanolamine, etc., 1,8-diazabicyclo [5.4.0] Undec-7-ene (DBU) ), 1,5-diazabicyclo [4.3.0] nona-5-ene) (DBN) and other organic alkaline substances such as cyclic amines. These alkaline catalysts may be used alone or in combination of two or more.
The amount of the alkaline catalyst used is not particularly limited, but is, for example, 1 to 30 parts by mass with respect to 100 parts by mass in total of the bisphenol compound and resorcinol.

The method of reacting the bisphenol compound and formaldehyde in the presence of an alkaline catalyst may be a known method. For example, a method of charging water, an alkaline catalyst, a bisphenol compound, and an aqueous formaldehyde solution in a reaction vessel equipped with a thermometer, a stirrer, and a cooling tube to maintain an arbitrary reaction temperature for an arbitrary reaction time can be mentioned. As a result, a reaction solution (RF solution) containing a BF reactant is obtained.
The reaction temperature is, for example, 10 to 100 ° C. The reaction time varies depending on the reaction temperature, but is, for example, 0.1 to 5 hours.

In step B, the amount of resorcinol used is set so that the ratio of the bisphenol compound to the total mass of the bisphenol compound and resorcinol is 10 to 90% by mass. The preferred range of the proportion of the bisphenol compound is as described above.

In step B, the amount of formaldehyde used is 0.7 to 3 mol, preferably 1 to 2 mol, with respect to 1 mol of resorcinol. When the amount of formaldehyde used is at least the above lower limit value, the adhesiveness between the rubber and the rubber reinforcing fiber is excellent, and when it is at least the above upper limit value, a large amount of unreacted formaldehyde does not remain in step B and thereafter. It is possible to suppress the volatilization of formaldehyde into the working environment atmosphere in the mixing process with rubber latex.

In step B, the method of reacting the reactant produced in step A with resorcinol and formaldehyde in the presence of an alkaline catalyst may be a known method. For example, a method of adding resorcinol and an aqueous formaldehyde solution to the RF solution obtained in step A as described above to maintain an arbitrary reaction temperature for an arbitrary reaction time can be mentioned. Since the RF solution obtained in step A contains an alkaline catalyst, it is not necessary to add the alkaline catalyst in step B, but an additional alkaline catalyst may be added if necessary.
The reaction temperature is, for example, 10 to 100 ° C. The reaction time varies depending on the reaction temperature, but is, for example, 0.1 to 5 hours.

<Rubber latex>
Examples of rubber latex include natural rubber (NR) latex, styrene-butadiene copolymer rubber (SBR) latex, vinylpyridine-styrene-butadiene copolymer rubber latex, acrylonitrile-butadiene copolymer rubber latex, and nitrile rubber (NBR). Latex, chloroprene rubber (CR) latex and the like can be mentioned. These rubber latexes may be used alone or in combination of two or more.
Water is usually used as the dispersion medium for the rubber latex.

<Other ingredients>
Examples of other components include epoxy compounds and silane coupling agents.
As the epoxy compound, known epoxy resins can be used, for example, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin. , Anthracene type epoxy resin, naphthol type epoxy resin, xylylene type epoxy resin, biphenyl aralkyl type epoxy resin, triphenylmethane type epoxy resin, dicyclopentadiene type epoxy resin, stillben type epoxy resin, sulfur atom-containing epoxy resin, phosphorus atom-containing Epoxy resin and the like can be mentioned. One type of these epoxy resins may be used alone, or two or more types may be used in combination.

Examples of the silane coupling agent include an amino group-containing silane coupling agent, an epoxy group-containing silane coupling agent, a vinyl group-containing silane coupling agent, a methacryloyl group-containing silane coupling agent, an acryloyl group-containing silane coupling agent, and a ureido group. Examples thereof include a silane coupling agent and an isocyanate group-containing silane coupling agent. Examples of the amino group-containing silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxy. Silane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2 -Aminoethyl-3-aminopropyltrimethoxysilane hydrochloride and the like can be mentioned. Examples of the epoxy group-containing silane coupling agent include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxy. Examples thereof include propylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane. Examples of the vinyl group-containing silane coupling agent include vinyltriethoxysilane. Examples of the methacryloyl group-containing silane coupling agent include 3-methacryloxypropyltrimethoxysilane. Examples of the acryloyl group-containing silane coupling agent include 3-acryloyloxypropyltrimethoxysilane. Examples of the ureido group-containing silane coupling agent include 3-ureidopropyltriethoxysilane. Examples of the isocyanate group-containing silane coupling agent include 3-isocyanatepropyltriethoxysilane. One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

In the adhesive composition (1), the mass ratio of the resole-type RF resin (1) to the rubber latex (resole-type RF resin (1): rubber latex) is 1: 3 to 1: 8 in terms of solid content. Preferably, 1: 4 to 1: 6 is more preferable. When the rubber latex is 3 times or more and 8 times or less the amount of the resol type RF resin (1), the adhesive force between the rubber and the rubber reinforcing fiber is more excellent. If the rubber latex is 3 times or more that of the resole type RF resin (1), the adhesive strength between the adhesive layer formed from the adhesive composition (1) and the rubber is better, and if it is 8 times or less, the adhesive. The adhesive strength between the adhesive layer formed from the composition (1) and the rubber reinforcing fiber is more excellent.

The solid content (% by mass) of the resor-type RF resin is determined by dividing the total amount of the bisphenol compound, resorcinol, and formaldehyde by the total amount of all the raw materials used in the reaction.

The total mass of the resole-type RF resin (1) and the rubber latex in terms of solid content is preferably 40% by mass or more, preferably 60% by mass or more, based on 100% by mass of the total solid content of the adhesive composition (1). More preferably, it may be 100% by mass.

The adhesive composition (1) preferably has a tensile breaking strength of 250 N or more, more preferably 300 N or more, and further preferably 350 N or more, as measured by the method described in Examples described later. preferable. The better the adhesiveness between the rubber and the rubber reinforcing fiber, the higher the tensile breaking strength.

The adhesive composition (1) can be produced by mixing a resole-type RF resin (1), a rubber latex, and, if necessary, other components.

<Use>
The adhesive composition (1) is used for adhering the rubber reinforcing fiber and the rubber. In other words, it is used in the production of rubber-based composite materials containing rubber and rubber reinforcing fibers.
Examples of the rubber reinforcing fiber include synthetic fibers such as polyamide fibers (nylon fibers), polyester fibers and aramid fibers; and inorganic fibers such as glass fibers and carbon fibers.
Examples of the rubber include natural rubber (NR), styrene-butadiene copolymer rubber (SBR), nitrile rubber (NBR), chloroprene rubber (CR) and the like.
The method of adhering the rubber reinforcing fiber and the rubber with the adhesive composition (1) may be the same as the method of adhering the rubber and the rubber reinforcing fiber with the RFL adhesive.

For example, the adhesive composition (1) is applied to a rubber reinforcing fiber (tire cord, etc.) and heat-treated to form an adhesive layer, and the formed adhesive layer and rubber containing rubber and a vulcanizing agent (sulfur, etc.) are contained. Contact with the composition and vulcanize. As a result, a rubber-based composite material including a rubber reinforcing fiber, a vulcanized product of the rubber composition, and an adhesive layer for adhering them can be obtained.
The adhesive layer formed by applying the adhesive composition (1) and heat-treating it is composed of a cured product of the resole-type RF resin (1) and rubber particles (derived from rubber latex) dispersed in the cured product. including. When the rubber composition is brought into contact with the adhesive layer and vulcanized, the action of the vulcanizing agent in the rubber composition causes vulcanization between the rubbers in the rubber composition and the rubber and the adhesive layer in the rubber composition. Vulcanization occurs with the rubber particles inside.
In addition to the rubber and the vulcanizing agent, the rubber composition may contain additives usually used in the rubber composition.
Before immersing the rubber reinforcing fiber in the adhesive composition (1), the surface of the rubber reinforcing fiber may be treated with an epoxy compound or the like.

The application of the rubber-based composite material is not particularly limited, and can be applied to various rubber products such as tires, belts, and hoses.

<Action effect>
The adhesive composition (1) described above can satisfactorily bond rubber and rubber reinforcing fibers. In addition, it has excellent storage stability.
In the conventional resorcinol-formaldehyde resin, the electron density at the ortho-position and the para-position of resorcinol is high and the reactivity is high, and formaldehyde easily undergoes an addition reaction and a condensation reaction proceeds in the presence of an alkaline catalyst. As a result, after production, it becomes a gelled state in about 24 hours at room temperature and becomes unusable.
On the other hand, since the resol type RF resin (1) uses a bisphenol compound having a lower reactivity than resorcinol, the progress of the addition condensation reaction with formaldehyde is suppressed, and the storage stability is excellent. For example, it can be used even after storage at room temperature for 2 months or longer.

[Second Embodiment]
The adhesive composition for rubber reinforcing fibers according to the second embodiment of the present invention (hereinafter, also referred to as “adhesive composition (2)”) is a specific resole-type bisphenol compound-resorcinol-formaldehyde resin (hereinafter, “). It is also referred to as a resole type RF resin (2) ”) and a rubber latex.
The adhesive composition (2) may further contain components other than the resole-type RF resin (2) and the rubber latex, if necessary, as long as the effects of the present invention are not impaired.
The adhesive composition (2) is the same as the adhesive composition (1) except that it contains the resol type RF resin (2) instead of the resol type RF resin (1).

<Resol type RF resin (2)>
The resole-type RF resin (2) has a total molar amount of bisphenol compound, resorcinol, 1 mol per 1 mol of the bisphenol compound and 0.7 mol per mol of resorcinol, or more, with respect to 1 mol of the bisphenol compound. It is a reaction product obtained by reacting 4 mol and 1 mol of resorcinol with 3 mol or less of formaldehyde in the presence of an alkaline catalyst, and the ratio of the bisphenol compound to the total mass of the bisphenol compound and resorcinol is 10. It is ~ 90% by mass.

The bisphenol compound is as described above, and the preferred embodiment is also the same.
The preferred range of the ratio of the bisphenol compound to the total mass of the bisphenol compound and resorcinol is the same as described above.

The resol type RF resin (2) is manufactured through the following step C.
Step C: The total molar amount of the bisphenol compound, resorcinol, 1 mol per 1 mol of the bisphenol compound and 0.7 mol per 1 mol of resorcinol, 4 mol and 1 mol of resorcinol per 1 mol of the bisphenol compound. A step of reacting 3 mol with a total molar amount of formaldehyde or less in the presence of an alkaline catalyst.

In step C, when the bisphenol compound, resorcinol, and formaldehyde are reacted in the presence of an alkaline catalyst, a reaction in which a methylol group is added to the benzene ring of the bisphenol compound and a reaction in which a methylol group is added to the benzene ring of resorcinol occur. After that, the condensation reaction proceeds between the methylol group adduct of the bisphenol compound and the methylol group adduct of resorcinol.

In step C, the amount of the bisphenol compound and resorcinol used is set so that the ratio of the bisphenol compound to the total mass of the bisphenol compound and resorcinol is 10 to 90% by mass. The preferred range of the proportion of the bisphenol compound is as described above.

In step C, the amount of formaldehyde used is 1 mol with respect to 1 mol of the bisphenol compound and 0.7 mol with respect to 1 mol of resorcinol, or more, 4 mol with respect to 1 mol of the bisphenol compound and 1 mol with resorcinol. The total molar amount is less than or equal to 3 mol, 2 mol per 1 mol of bisphenol compound and 1 mol per 1 mol of resorcinol, and 3 mol and resorcinol per 1 mol of bisphenol compound. It is preferably not more than the total molar amount of 2 mol with respect to 1 mol. When the amount of formaldehyde used is at least the above lower limit value, the adhesiveness between the rubber and the rubber reinforcing fiber is excellent, and when it is at least the above upper limit value, a large amount of unreacted formaldehyde does not remain in step C and thereafter. It is possible to suppress the volatilization of formaldehyde into the working environment atmosphere in the mixing process with rubber latex.

Examples of the alkaline catalyst include the same catalysts as described above.
The amount of the alkaline catalyst used is not particularly limited, but is, for example, 1 to 30 parts by mass with respect to 100 parts by mass in total of the bisphenol compound and resorcinol.

The method of reacting the bisphenol compound, resorcinol and formaldehyde in the presence of an alkaline catalyst may be a known method. For example, a method of charging a reaction vessel equipped with a thermometer, a stirrer and a cooling tube with water, an alkaline catalyst, a bisphenol compound, resorcinol, and an aqueous formaldehyde solution to maintain an arbitrary reaction temperature for an arbitrary reaction time can be mentioned. As a result, a reaction solution containing the resol type RF resin (2) can be obtained.
The reaction temperature is, for example, 10 to 100 ° C. The reaction time varies depending on the reaction temperature, but is, for example, 0.1 to 5 hours.

<Action effect>
The adhesive composition (2) described above can satisfactorily bond rubber and rubber reinforcing fibers. In addition, it has excellent storage stability.
In the conventional resorcinol-formaldehyde resin, the electron density at the ortho-position and the para-position of resorcinol is high and the reactivity is high, and formaldehyde easily undergoes an addition reaction and a condensation reaction proceeds in the presence of an alkaline catalyst. As a result, after production, it becomes a gelled state in about 24 hours at room temperature and becomes unusable.
On the other hand, since the resol-type RF resin (2) uses a bisphenol compound having a lower reactivity than resorcinol, the progress of the addition condensation reaction with formaldehyde is suppressed, and the storage stability is excellent. For example, it can be used even after storage at room temperature for 2 months or longer.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the following, bisphenol F and bisphenol A may be abbreviated as "bis F" and "bis A", respectively. "R: B" is the mass ratio of resorcinol: bisphenol compound. “Parts” and “%” indicate “parts by mass” and “% by mass”, respectively, unless otherwise specified.

<Example 1>
(Two-stage reaction, using screw F, R: B = 83: 17)
119.5 g of water and 1.5 g of sodium hydroxide were charged into a glass reaction vessel having a content of 3 L equipped with a thermometer, a stirrer and a cooling tube, and sodium hydroxide was dissolved at room temperature. 1.0 g of bisphenol F and 0.9 g of a 50% formaldehyde aqueous solution were added to this solution, and the mixture was stirred for 2 hours while controlling the solution temperature to 25 ° C. to carry out a methylolation reaction. Next, 5.0 g of resorcinol and 5.4 g of a 50% aqueous formaldehyde solution were added, and the methylolation reaction was carried out in the same manner with stirring at 25 ° C. for 2 hours.
To the obtained reaction solution (RF solution), 1970 g of rubber latex (Nipol2518FSH manufactured by Nippon Zeon, styrene-butadiene-2-vinylpyridine copolymer, polymer solid content of about 40%) was added and homogenized by stirring, and the mixture was made uniform in Example 1. The adhesive composition of was obtained.

<Examples 2 and 3>
(Two-stage reaction, using screw F, R: B = 57: 43, 35:65)
Change the 50% formaldehyde aqueous solution to add 2.6 g, 3.9 g of bisphenol F and bisphenol F to 2.4 g and 3.5 g, and add resorcinol to 3.4 g, 2.1 g and resorcinol 50% formaldehyde. The adhesive compositions of Examples 2 and 3 were obtained in the same manner as in Example 1 except that the amount of the aqueous solution was 3.7 g and 2.3 g.

<Example 4>
(Batch reaction, use of screw F, R: B = 83: 17)
119.5 g of water and 1.5 g of sodium hydroxide were charged into a glass reaction vessel having a content of 3 L equipped with a thermometer, a stirrer and a cooling tube, and sodium hydroxide was dissolved at room temperature. To this solution was added 1.0 g of bisphenol F, 5.0 g of resorcinol, and 6.3 g of a 50% formaldehyde aqueous solution, and the mixture was stirred for 2 hours while controlling the solution temperature to 25 ° C. to carry out a methylolation reaction.
1970 g of a rubber latex component (Nipol2518FSH manufactured by Nippon Zeon, styrene-butadiene-2-vinylpyridine copolymer, polymer solid content of about 40%) was added to the obtained reaction solution (RF solution), and the mixture was homogenized by stirring to carry out Examples. The adhesive composition of No. 4 was obtained.

<Examples 5 and 6>
(Batch reaction, use of screw F, R: B = 57: 43, 35:65)
Example 5 in the same manner as in Example 4 except that bisphenol F was changed to 2.6 g, 3.9 g, resorcinol was changed to 3.4 g and 2.1 g, and the 50% formaldehyde aqueous solution was changed to 6.1 g and 5.8 g. , 6 adhesive compositions were obtained.

<Example 7>
(Two-stage reaction, using screw A, R: B = 82: 18)
119.5 g of water and 2.0 g of sodium hydroxide were placed in a glass reaction vessel having a content of 3 L and equipped with a thermometer, a stirrer and a cooling tube, and sodium hydroxide was dissolved at room temperature. 1.1 g of bisphenol A and 0.9 g of a 50% formaldehyde aqueous solution were added to this solution, and the mixture was stirred for 2 hours while controlling the solution temperature to 25 ° C. to carry out a methylolation reaction. Next, 4.9 g of resorcinol and 5.3 g of a 50% aqueous formaldehyde solution were added, and the methylolation reaction was carried out in the same manner with stirring at 25 ° C. for 2 hours.
1970 g of rubber latex (Nipol2518FSH manufactured by Nippon Zeon, styrene-butadiene-2-vinylpyridine copolymer, polymer solid content of about 40%) was added to the obtained reaction solution (RF solution), and the mixture was made uniform by stirring in Example 7. The adhesive composition of was obtained.

<Examples 8 and 9>
(Two-stage reaction, using screw A, R: B = 53: 47, 33:67)
Change bisphenol A to 2.8 g, 4.1 g, 50% formaldehyde aqueous solution to be added with bisphenol A to 2.2 g, 3.2 g, and further add resorcinol to 3.2 g, 2.0 g, 50% formaldehyde to be added with resorcinol. The adhesive compositions of Examples 8 and 9 were obtained in the same manner as in Example 7 except that the aqueous solution was 3.5 g and 2.1 g.

<Comparative Example 1>
(Batch reaction, use of screw F, R: B = 0: 100)
The adhesive composition of Comparative Example 1 was obtained in the same manner as in Example 4 except that the bisphenol F was changed to 6.0 g, the resorcinol was changed to 0 g, and the 50% formaldehyde aqueous solution was changed to 5.4 g.

<Comparative Example 2>
(Batch reaction, no bisphenol compound used)
The adhesive composition of Comparative Example 2 was obtained in the same manner as in Example 4 except that the bisphenol F was changed to 0 g, the resorcinol was changed to 6.0 g, and the 50% formaldehyde aqueous solution was changed to 6.5 g.

<Evaluation>
The RF liquid or adhesive composition obtained in each example was evaluated as follows. The results are shown in Table 1.

(Stability of RF liquid)
The RF liquid was placed in a transparent bottle and stored at room temperature (25 ± 2 ° C.), and 24 hours and 7 days after the start of storage, the bottle was tilted and the fluidity of the RF liquid was visually confirmed. From the results, the stability of the RF solution was evaluated according to the following criteria.
◯: It had liquidity even after 7 days from the start of storage.
Δ: It had fluidity 24 hours after the start of storage, but solidified 7 days later.
X: It was solidified 24 hours after the start of storage.
When the adhesive composition, which was evaluated as ◯ in the evaluation of the stability of the RF liquid, was continuously stored 7 days after the start of storage, it had fluidity even after 3 months from the start of storage.

(Amount of residual formaldehyde in RF liquid)
Hydroxylammonium chloride was dissolved in water to prepare a 7.0% aqueous solution, and the pH was adjusted to 4.0 with dilute sulfuric acid or sodium hydroxide solution. A pH meter was used for pH adjustment (the same applies hereinafter).
6 ± 0.01 g of RF solution was precisely weighed in a beaker, 15 mL of methanol and 50 mL of pure water were added, and the pH was adjusted to 4.0 with 0.1 N sulfuric acid. 50 mL of a pH-adjusted hydroxylamine hydrochloride aqueous solution was added thereto, and the mixture was allowed to stand at room temperature for 30 minutes. During this time, formaldehyde generates hydrochloric acid and lowers the pH. After standing for 30 minutes, 1N aqueous sodium hydroxide solution was added under stirring to adjust the pH to 4.0. From the consumption of the 1N sodium hydroxide aqueous solution at this time, the residual formaldehyde amount (%) of the RF liquid was calculated by the following formula.
Residual formaldehyde amount (%) of RF liquid = (A × F × 3) / S
Here, A indicates the consumption amount (mL) of the 1N sodium hydroxide aqueous solution, F indicates the titer of the 1N sodium hydroxide aqueous solution, and S indicates the mass (g) of the RF solution.

(Tensile breaking strength)
A method for measuring the tensile breaking strength will be described with reference to FIG.
First, the test piece 1 was manufactured by the following procedure.
A 25 mm one end side in the longitudinal direction of a nylon plate 12 (made of nylon 66, 1 × 25 × 100 mm) was immersed in an adhesive composition. Next, the nylon plate 12 was taken out from the adhesive composition, excess adhesive composition was wiped off so as not to cause unevenness, and the mixture was dried at room temperature for 30 minutes. Next, the nylon plate 12 was placed in a dryer at 150 ° C. and heat-treated for 5 minutes to form a coating film 14 to obtain a nylon plate 10 with a coating film.
Next, two sheets of the coated nylon plate 10 are arranged along the longitudinal direction so that the coating film 14 portions overlap each other, and the carcass portion of the tire is placed between the coating films 14 of each coated nylon plate 10. Assumed rubber sheet 20A (natural rubber (RSS # 3 manufactured by Kojima Kogyo Co., Ltd.) 40 g, synthetic rubber (SBR1502 manufactured by Nippon Zeon Co., Ltd.) 60 g, carbon black (Cabot N330 manufactured by Cabot Japan Co., Ltd.) 40 g, process oil (NH-70S manufactured by Idemitsu Kosan Co., Ltd.) 5 g, anti-aging agent (Nocrack 6C manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) 2 g, rubber lubricant (stearic acid manufactured by Nichiyu Co., Ltd.) 2.5 g, zinc oxide (Sakai) Knead 4.5 g of zinc oxide manufactured by Chemical Co., Ltd. with a pressurized kneader, and 3.5 g of sulfur (sulfur manufactured by Tsurumi Chemical Industry Co., Ltd.) and vulcanization accelerator (Noxeller MSA manufactured by Ouchi Shinko Chemical Industry Co., Ltd.). -G) A rubber sheet obtained by kneading with a twin-screw roll at 95 ° C. for 5 minutes while adding 1.5 g) was sandwiched, set in a hot press machine, and heated by hot pressing to form a rubber layer 20. .. The hot press was performed under the conditions of 150 ° C., a press pressure of 100 kgf / cm ² , and 30 minutes using a spacer so that the rubber layer 20 became 1 mm. After hot pressing, excess rubber protruding from between the two coated nylon plates 10 was cut off. As a result, a test piece 1 in which two coated nylon plates 10 were adhered to each other via a rubber layer 20 was obtained.
Fifteen test pieces 1 were made for each adhesive composition.
For the produced test piece 1, the breaking load (N) when both ends of the test piece 1 were pulled by a tensile tester was measured. The breaking load was measured according to JIS L 1017. The crosshead speed at the time of measurement was 5 mm / min, and the chart speed was adjusted as appropriate. The average value of the breaking load of the 15 test pieces 1 was taken as the tensile breaking strength.

(Wetability)
In the evaluation of the tensile breaking strength, the adhesive composition is wetted with the nylon plate according to the following criteria from the state of application of the adhesive composition on the surface of the nylon plate when the nylon plate immersed in the adhesive composition is taken out. Gender was evaluated.
⊚: The entire adhesive surface was coated with a uniform film thickness.
◯: The film can be applied to the entire adhesive surface, but the film thickness is visually uneven.
X: There was repelling in a state where it could not be applied to a part of the adhesive surface.

The RF solutions of Examples 1 to 9 were excellent in storage stability. From this, it was found that the adhesive composition containing this RF liquid also has excellent storage stability.
Further, the adhesive compositions of Examples 1 to 9 had a sufficiently high tensile breaking strength and a good adhesive force between the nylon plate and the rubber.
In particular, the adhesive compositions of Examples 1 to 6 using bisphenol F as the bisphenol compound had good wettability to a nylon plate. From this, it was found that the wettability to the surface of the polyamide fiber was also good.
Comparing Examples 1 to 6, Examples 1 to 3 in which bisphenol F and resorcinol were sequentially reacted with formaldehyde were compared with Examples 4 to 6 in which bisphenol F and resorcinol were collectively reacted with formaldehyde. , The amount of residual formaldehyde in the RF solution was small.

On the other hand, the adhesive composition of Comparative Example 1 in which resorcinol is not used has low tensile breaking strength, inferior adhesive strength between the nylon plate and rubber, and is less useful as an adhesive for rubber reinforcing fibers. It was a thing. In addition, the wettability to the nylon plate was also inferior.
The RF solution of Comparative Example 2 in which the bisphenol compound was not used was inferior in storage stability.

Since the adhesive composition for rubber reinforcing fibers of the present invention contains a resorcinol-formaldehyde resin having excellent storage stability, it has less change over time than conventional RFL adhesives and is excellent in storage stability. Therefore, it is possible to manufacture the adhesive composition for rubber reinforcing fibers of the present invention in a chemical factory capable of sufficient environmental measures and deliver it to a rubber product manufacturing factory such as a tire. Since it is not necessary to manufacture the RFL adhesive at the rubber product manufacturing factory, the burden of environmental measures at the rubber product manufacturing factory can be reduced.

Claims (3)

Resorcinol-containing formaldehyde resin and rubber latex,
The resol-type resorcinol-formaldehyde resin is a reaction product obtained by reacting a bisphenol compound with 1 to 4 mol of formaldehyde with respect to 1 mol of the bisphenol compound in the presence of an alkaline catalyst, and with respect to resorcinol and 1 mol of the resorcinol. It is a reaction product obtained by reacting 0.7 to 3 mol of formaldehyde in the presence of an alkaline catalyst, and the ratio of the bisphenol compound to the total mass of the bisphenol compound and the resorcinol is 10 to 90% by mass. Adhesive composition for rubber reinforcing fibers. Resorcinol-containing formaldehyde resin and rubber latex,
The resol-type resorcinol-formaldehyde resin has a total molar amount of bisphenol compound, resorcinol, 1 mol with respect to 1 mol of the bisphenol compound, and 0.7 mol with respect to 1 mol of the resorcinol, or 1 mol of the bisphenol compound. It is a reaction product obtained by reacting 4 mol of formaldehyde with 3 mol of the total amount of formaldehyde with respect to 1 mol of the resorcinol in the presence of an alkaline catalyst, with respect to the total mass of the bisphenol compound and the resorcinol. An adhesive composition for rubber reinforcing fibers, wherein the proportion of the bisphenol compound is 10 to 90% by mass. The adhesive composition for rubber reinforcing fibers according to claim 1 or 2, wherein the bisphenol compound contains bisphenol F.

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