JPH06299134A - Adhesive composition for polyester fiber - Google Patents

Abstract

PURPOSE:To attain high adhesive force to fiber without lowering the fiber tenacity. CONSTITUTION:The adhesive composition contains resorcinol, formaldehyde and each latex at specific ratios and further contains a reaction product of a water-soluble polyurethane resin having two or more isocyanato groups and releasing a masking agent at a specific temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition for polyester fibers, and more particularly to an adhesive composition capable of adhering polyester fiber cords to rubber well.

[0002]

2. Description of the Related Art A polyester material, which is a linear polymer having an ester bond in the main chain, represented by polyester terephthalate, has stable mechanical properties and less stress relaxation as compared with materials such as nylon. Reinforcement of rubber articles such as tires, belts, air springs, rubber hoses in the form of filament threads, cords, cables, cord fabrics, canvas, etc. due to its excellent creep properties and excellent elongation elastic recovery rate. It is extremely useful as a material.
However, when a polyester fiber material is used as a reinforcing material for these rubber articles, the polyester fiber material is dense in a higher order structure and has less functional groups,
RFL liquid consisting of resorcinol formaldehyde initial condensate and rubber latex, which is an adhesive capable of satisfactorily adhering materials such as nylon and rayon, and rubber, can hardly obtain adhesion and is used as a reinforcing material for rubber parts. Can not.

For this reason, in the past, the surface of polyester was treated with alkali and amine, and the surface was -OH, -COOH, -N.
A method of increasing the number of active groups such as R (R is hydrogen or an alkyl group), an isocyanate compound, or an epoxy compound is used to introduce a compound having hydrogen bonding ability or a functional group capable of primary condensation onto the polyester surface, and then RFL A number of methods and adhesive compositions for treating with a liquid have been proposed.

[0004]

However, the treatment with alkali or amine has a drawback that the strength of the polyester fiber is deteriorated. Conventional isocyanate compounds, epoxy compounds, etc. are highly reactive and water, which is the solvent for RFL,
Since it reacts with RF in the RFL component, it is very difficult to form an adhesive liquid having a one-component composition, and the adhesiveness is impaired.
Therefore, it is necessary to perform the polyester adhesive treatment step in two steps, which requires extra equipment and steps, and further heat, which is not preferable from the viewpoint of resource saving and energy saving.

Further, the isocyanate compound and the epoxy compound form a primary bond with the polyester fiber material, and in the conventional RFL adhesive, the resin component is hardened to constrain each fiber filament constituting the polyester fiber cord, so that the cord elongation is caused. At times, the uniform stress sharing of each fiber filament is hindered, and the cord cannot exert its original strength.

Therefore, an object of the present invention is to provide an adhesive for polyester fibers with a one-part composition and to obtain a high adhesive strength without lowering the strength.

[0007]

In order to achieve the above object, the present invention has the following constitution. That is, 1 / 2.3 ≤ R /
F ≦ 1 / 1.1, preferably 1 / 2.0 ≦ R / F ≦ 1 / 1.3,
More preferably 1 / 1.8≤R / F≤1 / 1.5 (molar ratio) 1 / 10≤RF / L≤1 / 4, preferably 1 / 8≤RF /
L ≦ 1/5 (solid content weight ratio) 10 ≦ C ≦ 24, preferably 14 ≦ C ≦ 22 (wt%) 0.05 ≦ S ≦ 0.8, preferably 0.1 ≦ S ≦ 0.5, more preferably 0.1 ≦ S ≦ 0.3 ( % By weight) 4 ≦ E ≦ 30, preferably 12 ≦ E ≦ 25 (% by weight) are simultaneously satisfied, and the dissociation temperature of the masking agent for the isocyanate group of the reactive polyurethane resin is 100 ° C. or higher and 220 ° C. or lower,
It is preferably specified to be 130 ° C or higher and 220 ° C or lower. Further, it is specified that 10 ≦ a ≦ 80, preferably 30 ≦ a ≦ 60 (wt%), 20 ≦ b ≦ 60, preferably 25 ≦ b ≦ 50 (wt%) are simultaneously satisfied.

Polyester fibers preferably used in the present invention include polyethylene terephthalate.
ne terephthalate), polyethylene naphthalate (poly
ethylene naphthalate) and the like.

According to the above construction, the following effects occur. In the range of the RFL adhesive solution of the present invention, when the R / F is less than 1 / 2.3, the F amount is too much relative to the R amount, and R-F
Since the cross-linking between the two layers proceeds too much and the final RF resin network after heat treatment becomes too dense, the hardness of the RFL adhesive layer becomes too hard, while the R / F exceeds 1 / 1.1. On the contrary, the amount of F is too small relative to the amount of R, there is little cross-linking between R and F, the strength of the RFL layer is weakened, sufficient adhesion with rubber cannot be obtained, and the cord surface is sticky and workability is improved. It is not preferable.

Further, when RF / L exceeds 1/4, the RF amount is too large relative to the L amount, and as a result, the hardness of the RFL adhesive layer becomes too hard and the strength after dip treatment is lowered. I will end up. On the other hand, if RF / L is less than 1/10, the RF amount is too small relative to the L amount, and sufficient adhesion with rubber cannot be obtained.

Further, if C is less than 10% by weight, it is not possible to adhere sufficient adhesive solid matter to the cord when it is dipped in the adhesive, while if C exceeds 24% by weight. If the concentration is too high, the RFL adhesive solution will easily gel and become unstable.

Further, when S exceeds 0.8% by weight, the amount of alkali metal hydroxide, alkaline earth metal hydroxide or NH ₃ which is a reaction catalyst of F and R is too large, and the amount of R ₃ between R and F is increased. Since the cross-linking proceeds too much and the final RF resin network after heat treatment is too dense, the hardness of the RFL adhesive layer becomes too hard as a result. On the other hand, when S is less than 0.05% by weight, conversely, an alkali metal hydroxide, Since the amount of alkaline earth metal hydroxide or NH ₃ is too small, the liquid tends to gel and the stability is poor. As the alkali metal hydroxide, NaOH is generally preferable, but other alkali metal hydroxides such as KOH may be used.

When E is less than 4% by weight, sufficient adhesion with rubber cannot be obtained, and when it exceeds 30% by weight, the strength of the polyester fiber after heat treatment is significantly lowered. This is because the primary bond between the reactive polyurethane resin and the polyester fiber becomes excessive, restrains each fiber filament, and impedes uniform stress sharing of each fiber filament when the cord is stretched.

The masked reactive polyurethane resin is

[Chemical 1] Where R ₁ and R ₂ are hydrocarbon groups having 1 to 20 carbon atoms, and the reactive polyurethane resin can be a straight-chain, branched-chain, resin group, or aromatic group if it is water-soluble. It doesn't matter.
Further, M functions as a masking agent and is a strong hydrophilic group, for example, a carbamoyl sulfonate group (-NHCOSO ₃ N
a) etc. are desirable.

Further, the temperature at which the masking agent is dissociated from the isocyanato group must be higher than the drying temperature for the adhesive treatment. When the dissociation temperature is lower than the drying temperature (dry zone temperature), the isocyanato group reacts with water and does not participate in the adhesive mechanism between the fiber and the rubber, resulting in insufficient adhesive strength. On the other hand, when the temperature is higher than the adhesive application treatment temperature (temperature of hot zone), dissociation becomes insufficient and the adhesive force cannot be sufficiently obtained. That is, the dissociation temperature needs to be between the drying temperature and the adhesive application treatment temperature.

Next, regarding the latex component in the solution,
If a is less than 10% by weight, sufficient adhesion with rubber cannot be obtained,
On the other hand, when it exceeds 80% by weight, the selectivity of the adhered rubber to be adhered becomes large, which is not preferable, and the cost of the RFL liquid becomes too high.

Further, by using an appropriate amount of NR and / or IR latex, it is possible to suppress the decrease in strength during vulcanization, but if b is less than 20% by weight, there is no sufficient effect of suppressing the decrease in strength during vulcanization. On the other hand, if b exceeds 60% by weight, sufficient adhesion with rubber cannot be obtained. The VP latex usually contains 5 to 20% by weight of VP (vinyl pyridine). As the latex component, styrene-butadiene rubber (SBR) latex may be added as the balance of the VP, NR, and IR latexes. When SBR latex is added, the heat-resistant adhesive property can be further improved. In this case, when the weight% of the SBR latex solid content based on the total latex solid content is represented by c, 0 ≦ c ≦ 70,
It is preferable that 10 ≦ c ≦ 50 (wt%) be satisfied, and if c exceeds 70 wt%, the adhesiveness with rubber is lowered, which is inconvenient.

[0018]

EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples. Twist structure 1500d / as polyester fiber cord
2. Number of upper twists 40 times / 10 cm, number of lower twists 40 times / 10 cm, a) Low modulus type with 7.0 g / d raw cord strength ("NO" in Table 3
RMAL)), and b) two types of polyethylene terephthalate tire cords of high strength type (referred to as "high strength" in Table 3) having a raw cord strength of 7.8 g / d.

As a method for preparing the RFL adhesive solution in this example and the comparative example, first, resorcin is dissolved in soft water, then an aqueous solution of NaOH is added, then formaldehyde is added, and the mixture is left to mature at room temperature for 6 hours. , Latex was added, and the mixture was left to stand at room temperature for 24 hours for aging and then used for adhesive treatment.

The reactive polyurethane resin used in this example has three terminal isocyanato groups masked with carbamoyl sulfonate groups, and the dissociation temperature of the masking agent is 180 ° C. (trade name: Elastron, 30% aqueous solution (made by Ichigo Seiyaku Co., Ltd.) was used.
For the bath-type treatment, a 30% aqueous solution of a usual epoxy compound (trade name: Denacol EX314, manufactured by Nagase) was used as a pretreatment liquid. The adhesion treatments of Examples and Comparative Examples were performed under the following conditions.

[0021]

[Table 1] FIG. 1 shows an outline of the dip processing method. 1 indicates a drying zone, 2 indicates a hot zone, and 3 indicates a normalizing zone. In addition, the measuring method of each physical property value is as follows.

Breaking strength JI for all raw cords, dip cords, and vulcanized cords
Tensile test at a tensile speed of 300mm / min using Shimadzu autograph according to SL1017, and strength at break (kg)
I asked.

Adhesive Strength The adhesive-treated cord was embedded in an unvulcanized compounded rubber composition shown in Table 2 below, vulcanized at 153 ° C. for 20 minutes, and the cord was dug up from the obtained vulcanized product, It was peeled off from the vulcanized product by pulling at a speed of 300 mm / min, and the peeling resistance per cord was determined, and this was defined as the adhesive force (kg / bar).

[0024]

[Table 2]

Strength test in rubber after vulcanization The dip cord was embedded in the unvulcanized compounded rubber composition shown in Table 1 above, both ends of the cord were fixed and vulcanized at 153 ° C. × 40 minutes in a constant length state. After that, the vulcanized sample was taken out after it was naturally cooled in the fixed length state, and in order to avoid fluffing when peeling off the cord, cut the cord with the rubber around it with scissors and strip the surface rubber as much as possible. I dropped it. The breaking strength of the cord was measured by the above method with the surface rubber attached.

[0026]

[Table 3]

As a result, in Comparative Example 1, since the conventional epoxy pretreatment two-bath type adhesive treatment, the strength retention during dipping was 89.6%, which was poor.

In Comparative Example 2, the amount (E) of the isocyanate compound was below the range of the present invention, and the adhesive strength was insufficient.

In Comparative Example 3, since the amount (E) of the isocyanate compound is above the range of the present invention, the adhesive strength is sufficient, but the strength retention during dipping is as low as 87.0%.

In Comparative Example 4, since the amount (S) of NaOH is outside the range of the present invention, the dip strength and the vulcanization strength are low.

In Examples 1 and 2, since the composition is within the range of the present invention, the strong adhesive strength is good.

In Example 3, a high-strength type polyethylene terephthalate cord was used, but since the composition is within the range of the present invention, both strength and adhesive strength are good.

In Comparative Example 5, the amount of NR latex (N)
However, since the compounding amount is outside the range of the present invention, the adhesive force and the strength during dipping are good, but the strength during vulcanization is reduced.

Since the compositions of Examples 4, 5 and 6 are within the scope of the present invention, both strength and adhesion are good.

In Comparative Example 6, the amount (b) of NR latex was 70.
Since the composition is out of the range of the present invention, the adhesive strength is low.

In Comparative Example 7, the amount (a) of VP latex was 5.
0 is out of the range of the present invention, so the adhesive strength is low.

[0037]

According to the present invention, an adhesive for polyethylene fibers can be composed of a one-part composition, and in addition, the strength does not decrease,
The effect of obtaining high adhesive strength is obtained. Further, when the adhesive composition of the present invention is used, there is almost no odor, which is preferable in the working environment, and because the adhesive composition of the present invention can obtain good adhesive strength even when applied to polyamide fibers, The RFL adhesive can be integrated, and the workability can be greatly improved by reducing the labor of compounding.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a dip processing method.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display area C09J 161/18 JES 8215-4J D06M 15/564 // D06M 101: 32

Claims (1)

[Claims] 1. 1 / 2.3 ≤ R / F ≤ 1/1. 1 (molar ratio) 1/10 ≤ RF / L ≤ 1/4 (solid content weight ratio) 10 ≤ C ≤ 24 (wt%) 0.05 ≤ S ≤ 0.8 (wt%) 4 ≤ E ≤ 30 (wt%) 10 ≤ a ≤ 80 (wt%) 20 ≤ b ≤ 60 (wt%) (In the above formula, R / F is the total amount of resorcin / formaldehyde. RF / L is the ratio of the total amount of resorcin and formaldehyde to the total amount of rubber latex solids, C is the weight% of the total solids of the RFL adhesive liquid, and S is the alkali metal hydroxide relative to the total solids of the RFL adhesive liquid. Of water and / or alkaline earth metal hydroxide and / or NH ₃ aqueous solution in% by weight calculated as NH ₄ OH, E is a water-soluble solution having two or more isocyanato groups at which the masking agent dissociates at 100 ° C to 220 ° C. Of solid content of reactive polyurethane resin reactant (hereinafter referred to as reactive polyurethane resin) By weight based on the total solids content of the RFL adhesive, a is a weight% of the vinylpyridine (VP) latex solids based on the total latex solids, and b is a natural rubber (NR) and / or isoprene rubber (I
R) represents the latex solid content in% by weight based on the total latex solid content. ) Are simultaneously satisfied, an adhesive composition for polyester fibers.