JPS62282076A - Treatment of rubber reinforcing aromatic polyamide fiber - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for treating aromatic polyamide fibers for rubber reinforcement, which have improved adhesion to rubber. In particular, the adhesive strength of the present invention is high, and the rate of rubber adhesion to aromatic polyamide fibers when aromatic polyamide fibers are peeled off from a rubber composite molded product (Rubber coverage) is particularly high.
), and also relates to a processing method for providing aromatic polyamide fibers that are flexible and have excellent fatigue resistance.

<Prior art> Aromatic polyamide fibers generally have a high tensile strength and 2 modulus of elasticity, and are also excellent in dimensional stability and heat resistance, so they are used in tires under harsh conditions.

Suitable for reinforcing rubber products such as conduction belts, belts, hoses, etc. However, aromatic polyamide fibers are inert due to their molecular structure and are highly crystalline, so they have poor adhesion to rubber (usually used as an adhesive between aliphatic polyamide fibers and rubber). If resorcinol formalin latex (RFL) was used as is, it had the disadvantage that it could not form a strong bond with rubber.Therefore, we improved the adhesion between aromatic polyamide fiber and rubber. For example, a method of adhering aromatic polyamide fibers to rubber by subjecting them to epoxy treatment, heat treatment, RFL treatment, and heat treatment (Japanese Patent Publication No. 39-197) -10514), a method in which aromatic polyamide fibers are treated with a treatment liquid containing an epoxy compound, a condensate of phenols and aldehydes, and a tertiary amine, and heat treated, and then subjected to RFL treatment and heat treatment to adhere to rubber. (Japanese Patent Publication No. 52-43673), a method (A?
Japanese Patent Publication No. 53-37467), a method in which isocyanate and its derivatives are present at the interface between aromatic polyamide fibers and thermosetting resin (Japanese Patent Publication No. 53-37468), nato compounds.

Polyethyleneimine compound and methylolmelamine compound alone or in combination 1. A method of treating with a treatment solution containing ``C'' (Japanese Patent Publication No. 53-37473) has been proposed. In addition, the surface of the aromatic polyamide fiber is activated by low-temperature plasma treatment under reduced pressure, and then treated with a mixture of resorcinol/formali 7/initial condensate and rubber latex to improve its adhesion to rubber. Attempts are being made to improve. This method includes, for example, ``After subjecting aromatic polyamide fibers to low-temperature plasma treatment, resorcinol and
"A method for treating aromatic polyamide fibers for rubber reinforcement, which comprises treating with a mixed solution of a formaldehyde initial condensate and rubber latex" (Japanese Unexamined Patent Publication No. 19881/1981).

"The surface of aromatic polyamide fibers is treated in a low-temperature plasma gas atmosphere under reduced pressure, and then the treated fibers are adhesively treated with an adhesive composition consisting of a high molecular weight resorcinol-formaldehyde initial condensate and rubber latex. Adhesion method of characteristic aromatic polyamide fiber and rubber J (
% Publication No. 60-250036).

・ However, when the aromatic polyamide fibers treated by these conventional methods are peeled off from the rubber composite molded product, the rate of rubber adhesion to the fiber shaver is low (and the rate of rubber adhesion between the aromatic polyamide fiber material and rubber is low). The problem of insufficient adhesion and the inability to obtain sufficient adhesion has been a major obstacle to the use of aromatic polyamide, Do[1, for rubber reinforcement.

<Object of the invention> The present invention was made against the background of the following circumstances,
An object of the present invention is to provide excellent adhesive performance between aromatic polyamide fibers and rubbers.

<Configuration of the Invention> That is, the present invention treats aromatic polyamide fibers in an atmosphere of ionized active gas (plasma treatment) and then subsequently treats them with resorcinol formalin rubber latex (RF
L) is an ethylene urea compound represented by the following general formula (A) and an epoxy-modified phenol formalin condensate represented by the following general formula 〇), 8/B = 50150-807
This is a method for treating aromatic polyamide fibers for rubber reinforcement, which is characterized by treating with a treating agent added at a weight ratio of 20.

゛[Here, R is an aromatic or aliphatic hydrocarbon residue 1.

The aromatic polyamide fiber in the present invention means a fiber made of a polymer in which the number of repeating units having aromatic rings is small (80 units or more). R,, R,, may be the same or different and are selected from a hydrogen atom and a furkyl group having 5 or less carbon atoms.C is an alkyl group having 5 or less carbon atoms, and ℃ is a methyl group, ethyl group, propyl group, butyl group. group, pentyl group, etc., and [- is preferably a hydrogen atom.Also, Ar
As an example, can be exemplified. In addition, -X- is →-9? (R is preferably →- for alkyl having 5 or less carbon atoms. Ar' represents an aromatic ring. Examples of the aromatic ring include 1,4-phenylene group, 1,3-phenylene group) Group + 4.4'-biphenylene group, 1,5-naphthylene group, 2,6-naphthylene group.

2. Can you name the 5-pyridylene group, etc.?
The aromatic ring, which is preferably selected from a 1,4-phenylene group, is, for example, a 1,4-phenylene group (for example, a chlorine group).

Odor 1: Fluorine), lower alkyl groups (methyl, ethyl, isopropyl, n-furovyl groups), lower alkoxy groups (methoxy, ethoxy groups), sheets groups, acetyl groups, nitro groups, etc. may be included as substituents.

Typical examples of fibers made of these polymers or copolymers include polyvaraminobenz 7mide, polyparaphenylene terephthalamide, polyvara 7minopenzhydrazide terephthalamide, polyterephthalic acid hydrazide, and polyparaphenylene isophthalamide. Examples include fibers made of ramid, etc., or copolymers thereof.

The plasma treatment in the present invention refers to oxygen, ammonia,
-Carbon oxide, -nitrogen oxide, tetrafluoromethane, argon, helium, and other gases can be used alone. Increase reactivity.

The reason for the improvement in adhesion is not clear, but plasma treatment of aromatic polyamide fibers improves wetting with the treatment agent due to the generation of functional groups on the fiber surface or the formation of irregularities on the fiber surface. This is thought to be for the purpose of

As a result, the treatment agent can be applied uniformly to the cord surface, making it possible to uniformly disperse external stress during adhesive failure and fatigue failure, making stress concentration less likely to occur. In order to form an ionized state of gas, a so-called plasma processing device is used.

There are two types of plasma processing equipment: external electrode type and internal electrode type.

There are also capacitive coupling type, Il conductive coupling type, etc., and any of them may be used.

The operation processing conditions vary depending on the time, but for example, 1
A high frequency glow discharge of 0-'' Torr to 10 Torr is suitable.

If the gas pressure in the treatment tank exceeds 17rl OTorr, the temperature will rise significantly during glue discharge, and there is a risk of altering the surface of the aromatic polyamide fiber, so this is not preferable.
On the other hand, if the pressure is less than 10-'' Torr, the glue discharge will not be stable and it will be difficult to perform normal processing.

Thus, by plasma treatment, the surface treatment of aromatic polyamide fibers can be carried out at low temperatures and in a short time without impairing the mechanical properties of the fibers.

The processing agent of the present invention is a composition containing resorcinol/formalin/rubber latex, and the resorcinol/formalin/rubber latex used here is 01 to 1:8, preferably 1:0.5 to 1:5, more preferably is 1:1~1:
Used in a range of 4.

Examples of rubber latex include natural rubber latex,
There are styrene-butadiene copolymer latex, vinylpyridine-styrene-butadiene terpolymer latex, nitrile rubber latex, polypropylene rubber latex, etc., and these can be used alone or in combination.

Among these, vinylpyridine/styrene/butadiene terpolymer latex is used alone or in an amount of 1/2 or more [5], showing excellent performance.

The compounding ratio of resorcinol, formalin, and rubber latex is determined by the ethylene urea compound described below.

Also, depending on the addition ratio of epoxy-modified phenol-9 formalin resin condensate), the solid content ratio is 1:1 to 1:1.
15, preferably [, < is preferably in the range of 1:3 to 1:12. If the proportion of rubber latex is too small, the treated aromatic polyamide fiber material becomes hard and has poor fatigue resistance.

On the other hand, if the amount is too large, satisfactory adhesive strength and rubber adhesion rate cannot be obtained.

The mixing ratio of ethylene urea compound and epoxy modified phenol/formalin condensate is 50150 to RO/2
0 (weight ratio), and the mixture has a weight ratio of 0.5 to 30 wtq6, preferably 1.0 to 20 wtq6, relative to the above RFLK.
wt% added. If the amount of the mixture added is too small, good adhesion and rubber adhesion cannot be obtained. On the other hand, if the amount added is too large, the viscosity of the processing agent will significantly increase.1. This makes processing operations for fiber materials difficult. Moreover, when the adhesion force and rubber adhesion rate reach a saturation value, the effect of increasing the amount of the mixture added is not increased, and the cost only increases, and the treated fiber material becomes extremely hard ( The disadvantage is that the strength is reduced.

The ethylene urea compound added to the processing agent is represented by the following general formula (a).

Typical compounds include octadecyl isocyanate and hexamethylene diisocyanate.

Isophorone diisocyanate, tolylene diisocyanate, metaxylene diisocyanate.

Examples include reaction products of aromatic or aliphatic incyanates such as diphenylmethane diisocyanate, naphthylene diisocyanate, and triphenylmethane triisocyanate with ethyleneimine. In particular, aromatic ethylene urea compounds such as diphenylmethane diethylene urea have shown good results. give.

The epoxy-modified phenol/formalin condensate added to the processing agent has the following general formula (Bl).

Various compounds can be considered that satisfy the above (B), but the molecular weight is 1200 to 1300. ．． :r-boxy value 4.0-4.
Use one with 5eq/Kp (- gives good results.

In the present invention, the ethylene urea compound (5) and the epoxy-modified phenol/formalin condensate (B) have a catalytic effect on each other. In the formalin condensate, the epoxy ring opens and reacts, increasing adhesive properties and at the same time increasing the concentration of the adhesive itself.As a result, it forms a strong chemical bond with the amines generated in the rubber, resulting in strong adhesive properties. This prevents deterioration.

The above-mentioned processing agent is usually adjusted to contain a solid content of 10 to 25% by weight.

1. Adhering the treatment agent to the aromatic polyamide fiber material
Any method can be used, such as contact with a roller, application by spraying from a nozzle, or immersion in a bath liquid. The amount of solid content deposited on the aromatic polyamide fiber is O', 5''-120% by weight, preferably 3 to 10% by weight.The amount of solid content deposited on the fiber is In order to control the temperature, measures such as squeezing with a pressure roller, scraping with a souffle bar, blowing C1 with air, suction, and beating with a beater are used.

In the present invention, aromatic polyamide fibers are treated with a treatment agent (1). Afterwards 120℃ or higher, preferably 180-250℃
Dry and heat treat at a temperature of °C.

If the drying/heat treatment temperature is too low, adhesion with rubber will be insufficient. On the other hand, if the temperature is too high, the treatment agent deteriorates.1-1 Adhesive performance decreases.

By treating the aromatic polyamide fibers with the treatment agent of the present invention after plasma treatment as described above, it became possible to improve the adhesive strength between the aromatic polyamide fibers and the rubber. By plasma-treating the aromatic polyamide fibers, it is possible to improve the wettability of the aromatic polyamide fibers to the treatment agent, making it possible to uniformly apply the treatment agent to the surface of the aromatic polyamide fibers, eliminating uneven adhesion. At the same time, the plasma treatment also seems to have the effect of improving the adhesion between the aromatic polyamide fibers and the treatment agent.

It is thought that the synergistic effect of the effect of this plasma treatment and the effect of the treatment agent described above dramatically improved the adhesion performance between the aromatic polyamide fiber and rubber.

<Effects of the Invention> Fibers treated by the method of the present invention have improved adhesion with rubber without impairing moldability, compared to conventional methods.

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

In the examples, the cord peeling adhesive strength, T adhesive strength, and inter-ply peeling force 2 strength retention rate are values determined by pressure as follows.

Cord Peel Adhesive Strength Treatment Indicates the adhesive strength between the cord and rubber. Bury 5 cords near the surface of the rubber sheet and heat at 150°C under pressure.
After vulcanization for 30 minutes, 5 cords were vulcanized from the rubber sheet for 20 minutes.
The force required to peel off at a speed of 0 w/m is 41
It is displayed in 5 pieces.

T Adhesive Strength This shows the adhesive strength between the treated cord and rubber. The cord was embedded in a rubber block and heated at 150℃ for 30 minutes under pressure.
200 m from the rubber block.
/ m, and it takes 1. Kg of force
/tyn.
□ This shows the adhesive strength with the GRA 4 peel force treated cord.

The 2-ply processing cord is laid at a 90 degree angle.
Embedded in the rubber as a splice (cord density 27/inch) 1sor:.

After 30 minutes of vulcanization, the force required to peel both plies at a tensile speed of 200 m/m is expressed in 11/1 neh.

Rubber adhesion rate is a measure of the adhesion of rubber to fibers. The cord peeled off from the rubber during the inter-ply peel force measurement described above was observed with the naked eye, and the portion of the cord surface to which the rubber was attached is expressed as a percentage.

It is a measure of strength retention and fatigue resistance. Use a Gutdrich disc tester. Cord setting: 6 inches of expansion, 18 degrees of compression
% cyclic fatigue is applied 3.5 million times between rotating disks, and the amount of strength remaining is expressed as a percentage.

Examples 1-3. Comparative Examples 1 to 7 10% caustic soda aqueous solution 109.28% ammonia aqueous solution 30F was added to 260 PK of water and stirred thoroughly. Into the resulting aqueous solution, a resorcinol/formalin initial condensate (A0q6 acetone solution) reacted with an acidic catalyst was added. Add 6o2 1- (Stir thoroughly to disperse. Next, add Nilapol■
2518GL (manufactured by Nippon Zeon ■, vinylpyridine-styrene-butadiene-terpolymer latex 4° water emulsion) 24of and Nilaball ■ba-112 (manufactured by Nippon Zeon ■, styrene-getadiene copolymer 40% water emulsion) 100F. Dilute with 200f of water. The above-mentioned resorcin-formalin initial condensation dispersion was added to this diluted solution while stirring slowly, and then formalin (3
Add 7% aqueous solution) 201F at L5 and mix uniformly. Next, add 14 diphenylmethane diethylene urea to this mixture.
Add and mix an aqueous dispersion obtained by stirring and mixing 305 f, Neocol ■SW'' and 36 f of water in a ball mill with stirring.Next, mix with ECN1299 (Ciba Geigy ■
(manufactured by Daiichi Kogyo Seiyaku ■, dioctyl sulfosuccinate sodium salt) '0.1' f and methyl. 28fK of water to which 0.61 cellulose was added and dissolved
Add and disperse while stirring, add and mix, and use the resulting liquid mixture as a processing agent.

As the wholly aromatic polyetheramide fiber, paraphenylene rough 8 fluoroyl chloride 50 mol%. 3. 4'-diamino-diphenyl ether 2500 denier 1000 filament multifilament 2' obtained by wet spinning 40X40T/10 car
Twisted yarn 3000 denier/2ooo 5 6 MH
Ic-t=7 in a plasma processing apparatus using an oscillator of z
) L, in an oxygen gas atmosphere, under a reduced pressure of I Torr 2
00W for 1 minute to obtain an activated code on the surface.

The cord thus obtained was immersed in a treatment agent using a computer treater (tire cord processor made by CA Ritzler), dried at 150°C for 2 minutes, and then heat-treated at 230°C for 11 minutes. . After the treatment, the aromatic polyamide cord has a solid content of the treatment agent of 7. Owt% was attached.

The thus obtained treated hood was placed in an unvulcanized rubber containing a carcass containing natural rubber as the main component, 150°C, 3
Vulcanized for 0 minutes.

The above experiment is as shown in Table 1 (ethylene urea compound)
and epoxy-modified phenol/formalin condensate) with various weight ratios and subjected to plasma treatment,
Alternatively, the test was repeated for those that were not subjected to plasma treatment. The experimental results are shown in Table 1.

Table 1 (Note) Comparative Examples 4 to 6 in the above table were not subjected to plasma treatment.

*(A): Ethylene urea compound / CB): Solid content ratio (weight ratio) (B): Epoxy-modified phenol/formalin condensate Evaluation results of aromatic boria treated with plasma as above are shown in Table 2. show.

By treating mido fibers with an adhesive of a specific composition, the adhesive performance is greatly improved.

Examples 4 to 7 Cords were processed in the same manner as in Example 1, except that the plasma treatment conditions in Example 1 were changed to those shown in Table 2. The results are shown in Table 2.

Comparative Example 8 The tire hood made of the wholly aromatic polyetheramide fiber of Example 1 was immersed in the first treatment agent of the epoxy compound shown in Table 3, and then dried at 120°C for 2 minutes, and then treated at 230°C.
Heat treatment was performed at ℃ for 2 minutes. This was further immersed in the second treatment agent shown in Table 4, dried at 120°C for 2 minutes, and then
Heat treatment was performed at 0°C for 2 minutes. In the thus obtained wholly aromatic polyetheramide cord, the solid content of the first treatment agent was 3.1 wt%, and the solid content of the second treatment agent was 3.2 wt%.
It was attached at ℃. The resulting processed hood plasma-treated cord is similar to the two-bath treated cord FK without plasma treatment.
Compare and Adhesive.

Improved fatigue resistance (7).

Table 3 *1 Epoxidized products of phenol/formalin resin condensates manufactured by Chipa Geigy Table 4

Claims (1)

[Claims] After the aromatic polyamide fiber is treated in an atmosphere of ionized active gas (plasma treatment), it is subsequently treated with resorcinol.
The following general formula (
An ethylene urea compound represented by A) and the following general formula (B
) A method for treating aromatic polyamide fibers for rubber reinforcement, which comprises treating with a treatment agent containing an epoxy-modified phenol/formalin condensate represented by A/B at a weight ratio of 50/50 to 80/20. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) [Here, R is an aromatic or aliphatic hydrocarbon residue, n is 0
, 1 or 2. When n=0, the terminal group is hydrogen. ] ▲There are mathematical formulas, chemical formulas, tables, etc.▼(B) [Here, R' is -O-(CH_2)k-Cl, -O-(
CH_2) l-OH or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R'' is either H, CH_3, C_2H_5, k, l, m are integers from 1 to 4, m' is an integer from 1 to 5 Integers a and b are integers from 1 to 5, and a+b≦6.]