JPH082971B2 - Method for producing rubber composite reinforced with polyester fiber or aromatic polyamide fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for producing a composite of a fiber and a rubber reinforced with polyester fiber or aromatic polyamide fiber, which has excellent water resistance and steam resistance against rubber. Regarding

<Prior Art> Polyester fibers and aromatic polyamide fibers have attracted attention in the field of industrial materials due to their excellent physical properties.
It is already used for rubber reinforcement applications such as tire cords, rubber hoses, conveyor belts, transmission belts, and rubberized fabric composite materials. Among these rubber products reinforced with fibers, the rubber hose and the power transmission belt have one of the most required properties in terms of the manufacturing method and application, that is, the water resistance and the steam resistance against the cord and the rubber. For polyester and aromatic polyamide fibers, many industrially practical adhesive liquids and adhesive treatment methods have been studied and actually used. However, polyester and aromatic polyamide fibers do not adhere to one-bath type RFL (mixture of resorcin / formaldehyde condensate and rubber latex) like aliphatic polyamide fibers, and one-bath treatment method of epoxy compound / RFL , A two-bath method of isocyanate compound / RFL, or a method of adding a specific compound to RFL (for example, JP-B-46-11251 and JP-B-48-8).
733, JP-A-58-19375, JP-A-60-146084
JP-A-61-19878, JP-A-62-141174 and JP-A-62-141180) are generally known.

In particular, the above isocyanate compound / RFL two-bath treatment method (for example, USP3.090.716) is known to obtain high adhesion between polyester fiber or aromatic polyamide fiber and rubber, and pressurized water is used as a vulcanization method. In the case of autoclave vulcanization by steam, the adhesiveness between the polyester fiber or the aromatic polyamide fiber and the rubber of the obtained rubber composite, especially the water-resistant and steam-heat resistant adhesiveness as a product, is not yet sufficient.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to provide a high degree of water-resistant and steam-heat resistant adhesion with rubber during vulcanization or as a product without impairing the properties of the polyester fiber or the aromatic polyamide fiber. It is intended to provide an adhesive liquid capable of imparting the above, and thereby to provide a method for producing a composite of fiber and rubber having excellent rubber adhesiveness.

<Means for Solving Problems> The method for producing a rubber composite reinforced with polyester fibers or aromatic polyamide fibers of the present invention is a cord and / or knitting of a raw yarn made of polyester fibers or aromatic polyamide fibers. In a method for producing a fiber-reinforced rubber composite by forming a woven fabric, subjecting to adhesive treatment and heat treatment, embedding in rubber, and vulcanizing under pressured steam, the adhesive treatment and heat treatment are carried out with an active isocyanate group. After a solution of the contained compound in an organic solvent was applied and heat treated, the reaction molar ratio of formaldehyde (A) and resorcin (B) (A /
B) is 0.1: 1 to 8: 1 resorcin / formaldehyde condensate (C), rubber latex (D), and compound (F) represented by the following general formula (I): (C) / (D ) =
1: 1 to 1:15 (weight ratio of solid content), and [(C) /
(D)] / (F) = 1: 0.1 to 1: 2 (solid content weight ratio), and the heat treatment is performed by treatment with an aqueous adhesive treatment liquid. [However, X and Y in the formula are -Cl, -Br, -H, -OH,-
SH, -NH2, -NO2, C1-C8 alkyl, aryl or aralkyl group, -COOH, or (Wherein R ₁ , R ₂ : -H, an alkyl, aryl or aralkyl group having 1 to 8 carbon atoms), and Z is (Wherein R ₃ and R ₄ are —H or an alkyl group having 1 to 8 carbon atoms), —Sx— (where S is a sulfur atom, and x is an integer of 1 to 8).
Or -S-Oy- (where S: sulfur atom, O: oxygen atom,
y: an integer of 1 to 2), and n represents 0 or an integer of 1 to 15. As the polyester fiber and the aromatic polyamide fiber used in the present invention, those substantially consisting of polyethylene terephthalate and substantially poly-p
Preferred are those consisting of phenylene terephthalamide, but other polyester fibers and aromatic polyamide fibers can also be used.

In order to obtain a raw cord, first, draw an appropriate number of fibers and ply them. In this case, the number of twists is arbitrary, but for example, the number of twists having the same twist coefficient is applied to the next twist. Next, a plurality of fibers that have undergone undertwisting are combined, and twisting in the opposite direction to the undertwisting is applied to obtain a raw cord. In addition,
In the case of reinforcing cords for power transmission belts, after under twisting in this way, the multiple cords are twisted together and twisted in the opposite direction to make raw cords, but in the case of reinforcing cords for rubber hoses, only the under twist is applied. It is often used as a raw code in.

On the other hand, in the case of a knitted fabric, it may be formed into an arbitrary knitted fabric after being twisted as described above, but in many cases, it is applied to the knitted fabric without twisting, and various knitted fabrics are obtained. It is often said that. The raw cord or knitted fabric thus obtained is then subjected to an adhesive treatment and a heat treatment.

The active isocyanate group-containing compound for the first bath used in the present invention includes polymethylene-polyphenyl isocyanate (for example, trade name: "PAPI" or "PAPI").
135, Kasei Upjohn's Upjohn), diphenylmethane diisocyanate (for example, trade name:
Examples thereof include active isocyanate group-containing compounds such as "ISONATE" 125M or "ISONATE" 143L, manufactured by Kasei Upjohn. In addition, a solution containing these compounds, such as "Chemlok" 233 (trade name, Lord Far East.
Incoporated) and the like are also used.

A solution of these active isocyanate group-containing compounds in an organic solvent is applied and heat treated. In the adhesive solution applied thereafter, formaldehyde (A) and resorcin (B) are usually reacted in the presence of an alkali catalyst. Preferred (A) / (B) (molar ratio) is 1: 1 to 3: 1. The preferable solid content weight ratio (C) / (D) of the condensate (C) and the rubber latex (D) is 1: 2 to 1:10. A preferable solid content weight ratio (E) / (F) of the solid content in the aqueous composition (E) (hereinafter referred to as RFL liquid) and the compound (F) represented by the general formula (I) is 1: 0.2 to. It is 1: 1.

Here, the compound (F) represented by the above general formula (I) means, for example, JP-B-46-11251 or JP-B-48.
Those described in Japanese Patent No. 8733 are preferable, and specifically, 2,6-bis (2 ', 4'-dihydroxy-phenylmethyl) -4-chlorophenol (for example, trade name:
"VULCABOND" -E, manufactured by Barnax or "Denapond", manufactured by Nagase Kasei), 2,6-bis (2 ', 4'-dihydroxy-phenylmethyl) -4-promphenol, 2,6-bis ( 2 ', 4'-dichlorophenylmethyl)
-4-Chlorophenol and resorcinol polysulfide and the like can be mentioned. In addition, these compounds (F) are, for example, compounds derived from halogen or phenol, formaldehyde and phenol derivatives or polyhydric phenols and sulfur chloride (for example, trade name: "Sumikanol" 750, manufactured by Sumitomo Chemical Co., Ltd.) and two kinds thereof. It may be a mixture of the above. Of these, compounds derived from halogenated phenols, formaldehyde and phenol derivatives are most preferably used.

Examples of the rubber latex (D) include natural rubber latex, styrene-butadiene rubber latex, acrylonitrile-butadiene latex, chlorobrene rubber latex, vinyl pyridine-styrene butadiene rubber latex and chlorosulfonated polyethylene latex, which can be used alone. It is, of course, preferable to use 2 to 3 kinds in combination.

In the present invention, when the solid weight ratio (C) / (D) of the condensate (C) of formaldehyde and resorcin and the rubber latex (D) is less than 1: 1, the treated cord and The tackiness of the knitted fabric is increased, which is not preferable.

The compound (F) represented by the general formula (I) is added to the RFL solution in a weight ratio of 1: 0.1 to 1: 2, preferably 1: 0.2 to 1: 1.

When this ratio is less than 1: 0, satisfactory adhesiveness cannot be obtained, and when it exceeds 1: 2, the flexibility of the cord and the knitted fabric is deteriorated, which is not preferable.

After compound (F) is mixed with RFL solution, it is usually used after aging for 12 hours to 7 days, preferably 1 to 4 days at 10 to 30 ° C.

In the adhesive liquid for the second bath used in the present invention, a blocked isocyanate compound, an epoxy compound, a compound having a triazine ring, a surfactant and a softening agent are added to the extent that the adhesiveness is not impaired. It is possible to contain more than one species.

In particular, in order to further enhance the object of the present invention, it is preferable to add 0.05 to 10 (wt%) of organopolysiloxane to the adhesive solution of the second bath and mix it. The organopolysiloxane is usually represented by the following general formula (II) in addition to dimethylpolysiloxane, diphenylpolysiloxane, and methylphenylpolysiloxane called silicone oil having a viscosity of 5 to 200,000 centipoise at 25 ° C. And modified polysiloxanes.

(However, in the formula, R ₁ , R ₂ , R ₃ and R ₄ are —CH ₃ , —OH,
-COOH, -NH ₂ and _{- (C 2 H 4 O)} a - (C 3 H 6 O) b -H
From a selected group, at least one is a group other than -CH _3. a and b show the integer of 0-30, m and n show the integer of 1 or more. Among these organopolysiloxanes, those having water dispersibility by modification are not preferable. It is desirable that an ordinary silicone oil is made into an emulsion type by using an emulsifier or the like and then blended in an aqueous adhesive.

The amount of the adhesive liquid adhered to the fiber or knitted fabric is usually 0.01 to 12.0 with the isocyanate compound in the first bath as the solid component.
%, Preferably 1.0 to 7.0% by weight.

In the present invention, the fibers or the knitted fabric are treated with the adhesive liquids of the first and second baths, and then heat treated.

Usually, heat treatment is performed at a temperature of 120 to 250 ° C. for 1 to 3 minutes, which is preferable for obtaining sufficient adhesiveness with rubber.

In the present invention, the treated cord is embedded and then heated and vulcanized by pressurized steam in an autoclave to obtain a product.

Normally, gauge pressure: 1.0 to 9.5 kg / cm ² (temperature: 120 to 180 ° C
It is vulcanized and molded by the steam of (below).

The rubber molded product obtained according to the present invention has extremely good steam-heat adhesion resistance between rubber and fiber, and the rubber molded product is 50
After being soaked in warm water at ℃, the water resistance is also very good.

<Examples> Hereinafter, the present invention will be specifically described with reference to Examples.

Examples 1 to 11 and Comparative Examples 1 to 10 As the active isocyanate group-containing compound in the adhesive in the first bath, a 10% trichlene solution of "PAPI" (manufactured by Kasei Upjohn) was used. As the adhesive for the second bath, the compounding ratio of formaldehyde (A) and resorcin (B) (A) /
(B) (shown in the table), compounding ratio (C) / (D) (shown in the table) of compound (F) of rubber latex (D) to condensate (C) of formaldehyde and resorcin as compound (F) 2,6-bis (2 ', 4'-dihydroxyphenylmethyl) -4-chlorophenol (trade name: "VULC
Various adhesives were prepared using ABOND "(Valka Bond) -E, manufactured by Barnax Co., Ltd. The concentration of the adhesive liquid is 20% by weight. As the woven fabric for the reinforcing material, polyester fiber (manufactured by Toray Co., Ltd., "Tetron" type 702C) 1000 denier plain weave (30 warps / in, 30 wefts / in) or aromatic polyamide fiber (Dupont, "Kevlar" type 956) 100
A 0 denier plain weave (30 warps / in, 30 wefts / in) was soaked in the adhesive solution for the first bath, then heat-treated at 220 ° C for 1 minute, and then adhered for the second bath. Soak in chemical solution
It was dried at 130 ° C for 1 minute and then heat-treated at 220 ° C for 1 minute. The amount of the first bath adhesive liquid deposited was 3.5% by weight, and the amount of the second bath adhesive liquid deposited was 3.0% by weight.

The steam resistance and water resistance were measured by the following methods.

1) Vulcanization method In order to reproduce the pressurized steam vulcanization by autoclave in the laboratory, the polyester fabric or aromatic polyamide fabric treated as described above is dipped in water at room temperature for 7 days, then pulled up and immediately embedded in various rubbers and molded. Medium 175 ℃
* Vulcanized for 20 minutes.

2) Adhesion resistance against steaming heat In the obtained rubber-molded vulcanizate, the initial adhesive force for peeling between the rubber and the fabric was measured according to the method of JIS K-6328-1977.

3) Water-resistant adhesive strength A test piece of the same type of rubber-vulcanized vulcanizate obtained above was dipped in warm water of 50 ° C. for 48 hours, and the peel adhesive strength was measured by the same method to obtain the water-resistant adhesive strength.

The results are shown in the table. As you can see from the table,
According to the method of the present invention, it is possible to obtain a rubber composite which significantly improves the adhesiveness as compared with the conventional adhesive formulation.

In Comparative Example 10, as an adhesive for the first bath, an aqueous solution of an epoxy compound (trade name: "Denacol" EX-313, manufactured by Nagase Kasei Co., Ltd.) was applied at 1% (solid content% by weight), and then for the second bath. The results are obtained by using Example 8 as the adhesive, but the steam-heat adhesive strength and the water-proof adhesive strength are obviously inferior to those of Example 8.

 The rubber compound used was based on the following formulation.

Rubber name: CSM CSM-40: 100 parts MgO: 4 parts Hard clay: 60 parts Process oil: 30 parts Vulcanization accelerator: 1 part Rubber name: CR Neoprene: 100 parts MgO: 4 parts MAF Black: 20 parts Hard clay : 80 parts Process oil: 12 parts ZnO: 5 parts Antioxidant: 2 parts Vulcanization accelerator: 1 part Rubber name: NBR NBR: 100 parts HAF black: 51 parts Plasticizer: 15 parts Stearic acid: 1 part Sulfur: 1.5 parts ZnO: 5 parts Anti-aging agent: 2 parts Vulcanization accelerator: 1.5 parts Rubber name: SBR NR: 70 parts SBR: 30 parts HAF Black: 40 parts Stearic acid: 2 parts ZnO: 5 parts Process oil: 3 Part Sulfur: 2 parts Anti-aging agent: 2 parts Vulcanization accelerator: 1 part Example 12, Comparative Example 11 1000 denier "Tetoron" raw yarn used in Examples 1-7 and Comparative Examples 1-5, two type 702C are aligned, and 10T / 10cm
Was twisted in the S direction to obtain a raw cord. The raw cord was treated with the adhesive used in Example 2 and Comparative Example 1, and 1
After the bath treatment, heat treatment was performed at 220 ° C. for 1 minute, and after the second bath treatment, heat treatment was performed at 150 ° C. for 1 minute and 220 ° C. for 1 minute to prepare a treatment cord.

This treatment cord was braided on an inner tube made of CSM rubber, and CSM rubber was further covered on the inner tube, and the vulcanized hose was autoclaved at 150 ℃ × 3.
Pressure steam vulcanization was carried out for 0 minutes.

About the part 10 cm inside from the end surface of this hose after vulcanization
The peeling adhesive force between the covering rubber and the blade coat layer was measured according to JIS K-6301-1962. As a result, Example 12 using the adhesive of Example 2 showed a peel adhesion of 5.5 kg / in, while Comparative Example 11 using the adhesive of Comparative Example 1
The peel adhesive strength of only 1.5 kg / in was obtained, and the adhesive of the present invention was highly resistant to the decrease in adhesiveness during steam vulcanization.

Example 13, Comparative Example 12 1000 denier "Tetoron" yarn used in Example 12 and two type 702C are aligned and twisted in the Z direction of 20T / 10cm, and then 5 twists of this twisted cord are added. A 10T / 10cm twist in the S direction was applied to make a raw cord. The adhesive treatment used in Example 6 was performed, heat treatment was performed at 220 ° C. for 1 minute after the first bath treatment, and heat treatment was performed at 150 ° C. for 1 minute and 220 ° C. for 1 minute after the second bath treatment. It was made. (Example 13).
On the other hand, in Example 13, “Valka Bond” is not added.
A treatment code was similarly prepared for RFL (Comparative Example 12).

Embedding these processing cords in CR rubber, 150 ℃ × 30
It was vulcanized under pressured steam in an autoclave for a minute to prepare a transmission belt. The peeling adhesive force required to peel off one cord from this transmission belt was determined. In the case of the belt obtained in Example 13, only a peeling force of 5.0 kg / cord was obtained, and a large effect of the addition of "VALCABOND" -E of the present invention was obtained.

<Effects of the Invention> According to the present invention, it is possible to obtain a rubber composite reinforced with polyester or aromatic polyamide fibers, which has good steam heat resistance during vulcanization and good water resistance. It was

Claims (1)

[Claims] 1. A cord and / or a knitted fabric comprising a raw yarn made of polyester fiber or aromatic polyamide fiber,
In the method for producing a fiber-reinforced rubber composite by subjecting it to adhesive treatment and heat treatment, embedding in rubber, and vulcanizing it under pressurized steam, the adhesive treatment and heat treatment are carried out using organic compounds of active isocyanate group-containing compounds. Applying a solution of solvent,
After heat treatment, the reaction molar ratio (A / B) of formaldehyde (A) and resorcin (B) is 0.1: 1 to 8: 1, resorcin-formaldehyde condensate (C), rubber latex (D), and The compound (F) represented by the following general formula (I) was prepared by adding (C) / (D) = 1: 1 to 1:15 (solid content weight ratio) and [(C) / (D)] / ( F) = 1: 0.1 to 1: 2
Characterized in that it is carried out by a method of treating with an aqueous adhesive treatment liquid contained in a ratio of (solid content weight ratio) and heat treatment.
A method for producing a rubber composite reinforced with a polyester fiber or an aromatic polyamide fiber. [However, X and Y in the formula are -Cl, -Br, -H, -OH,
-SH, -NH _2, -NO _2, alkyl of 1 to 8 carbon atoms, aryl or aralkyl group, -COOH, or, (Wherein R 1 and R 2 are —H, or an alkyl, aryl or aralkyl group having 1 to 8 carbon atoms), and Z is (Here, R3 and R4 are -H or an alkyl group having 1 to 8 carbon atoms), -Sx- (where S is a sulfur atom and x is 1 to 8).
Or an integer of -S-Oy- (where S is a sulfur atom, O
Is an oxygen atom, y is an integer of 1 to 8), and n is 0 or an integer of 1 to 15. ]