KR100204756B1 - Water-based composition for a binder for pulverized rubber particle - Google Patents

Abstract

The present invention provides a water-based composition for a binder of pulverized rubber particles, which has an excellent effect of adhesion and mixing with the nonpolar rubber pulverized product.

The composition according to the present invention is characterized by containing 10-50 parts by weight of the aqueous one-component of the following (1) and 50-90 parts by weight of the aqueous two-component of the following (2).

(1) styrene-butadiene latex having a butadiene content of 50% or more;

(2) Styrene-butadiene latex modified at least 30% by acid monomer and having a styrene content of at least 30%.

Description

Aqueous composition for binders of ground rubber particles

The present invention relates to an aqueous composition, and more particularly, to an aqueous composition for a binder (Binder) having excellent elasticity, low cost and excellent physical properties as a binder for bonding pulverized rubber particles.

In order to recycle rubber products such as waste tires and weather strips, desulcanization is used as recycled rubber, or pulverized into particles and treated with a binder, followed by molding.

The binder used for the purpose may be an epoxy-based or polyurethane-based binder, double epoxy-based binder has been limited in use due to the lack of flexibility due to product cracks due to the difference in elasticity with the crushed rubber after molding the product. On the other hand, polyurethane-based binders can be divided into solvent type and non-solvent type. Solvent type has low viscosity and excellent mixing property due to excellent wetting with crushed rubber particles, but environmental pollution and dryness due to toxic solvent. There is a bad problem. On the other hand, the solvent-free type does not have the above problems, but there is a limit to increase the molecular weight due to the high viscosity by not using a solvent, poor mixing properties with the crushed rubber particles, and poor curing, which has a disadvantage of poor workability.

Polyurethane binders are also highly chemically polar, while most recyclable ground rubbers are non-polar rubbers such as natural rubber, styrene-butadiene rubber and ethylene-propylene-diene terpolymers. There is also a problem of poor interfacial adhesion. Therefore, only nonpolar ones are used as raw materials for the binder in order to improve the interfacial adhesion between the ground rubber and the binder. However, since the price of the non-polar raw material is expensive, the price of the binder is increased, which leads to an increase in the processing cost of the crushed rubber, which has been a challenge in expanding the use of the crushed rubber and diversifying products.

It is an object of the present invention to solve such problems and to provide an aqueous binder which is excellent in workability, inexpensive, has low environmental pollution, and has excellent interfacial adhesion with ground rubber.

In order to achieve the above object, the present invention provides an aqueous composition for a binder of pulverized rubber particles, characterized in that it contains one aqueous component of the following (1) and two aqueous components of the following (2).

(1) styrene-butadiene latex having a butadiene content of 50% or more;

(2) Styrene-butadiene latex modified at least 30% by acid monomer and having a styrene content of at least 30%.

Hereinafter, the composition of the present invention will be described in detail.

The binder for pulverized rubber particles according to the present invention contains the first aqueous component, the second aqueous component and other additives. The first aqueous component and the second aqueous component are as described briefly above, and a detailed description thereof will be described below. Examples of the additive contained in the binder of the present invention include sulfur, thiazole vulcanization accelerators, dithiocarbamate vulcanization accelerators, amines, and the like, which are also specifically described below.

Commercially available natural rubber latex and acrylic emulsion may be used as the water-based binder for pulverized rubber.However, in the case of natural rubber latex, despite the excellent mechanical properties and low price, the rubber-based binder works by adding ammonia to stabilize the latex. It is not suitable as a binder of pulverized vulcanized rubber particles for outdoor use due to poor environment and poor heat resistance and weather resistance due to chemical structure. In addition, chloroprene latex and acrylic emulsions are polar, so they are not applicable to most nonpolar waste rubbers.

Accordingly, in the present invention, styrene-butadiene latex having low cost and excellent heat resistance, weather resistance, and abrasion resistance was used in view of the above-mentioned disadvantages of the binder. Specifically, the solid content of the binder was adjusted to be maintained at 50% by weight or more to facilitate drying. When the solid content of the binder is less than 50% by weight, molding failure occurs due to the difference in internal and external dryness of the molded product due to excessive moisture, and productivity is not preferable due to excessive processing time due to drying. In addition, modified styrene-butadiene latex (aqueous two-component) was mixed to improve mechanical properties of the binder, and a crosslinked structure was appropriately introduced to compensate for mechanical properties.

In order to introduce such a crosslinked structure, styrene-butadiene latex having a content of 50% or more of butadiene having a double bond in the molecular structure is preferably used (aqueous one component). In addition, styrene-butadiene latex having a styrene content of 30% or more and 30% or more modified by an acid monomer was used in combination in order to increase the mechanical rigidity of the product because the main use of recycled products is a flooring material (aqueous two-component). Examples of acid monomers used for the modification of the aqueous two-component include methyl methacrylate, maleic anhydride, vinyl acetate, acrylic acid and the like.

In mixing an aqueous one component and an aqueous two component, the quantity of an aqueous one component is 10-50 weight part, and the quantity of an aqueous two component is 90-50 weight part.

If the ratio of one aqueous component is less than 10 parts by weight, the stiffness of the product is too large, increasing the mechanical stiffness such as hardness and strength, but the absorption of vibration and shock or slip resistance is reduced, and It is not preferable that the difference in elastic force is large. When the proportion of the aqueous one component is 50 parts by weight or more, the mechanical stiffness of the product is reduced, which is not preferable for use as a flooring material.

On the other hand, various additives used in the preparation of the binder were emulsified in an appropriate concentration in water, for example 40-70% by weight, using an emulsifier so that they could be easily dispersed in styrene-butadiene latex, and the average particle size of the dispersed particles It was used by milling (Milling) to be 2㎛ or less. If the particle size of the additive is more than 2㎛ not only can not exhibit the inherent performance of the additive, but also may act as an impurity in the molded article to reduce the mechanical properties, and may result in a decrease in the storage stability of the binder Not desirable

As the vulcanizing agent, sulfur, which is generally used most in rubber, was used in an amount of 1 to 3 parts by weight. In addition, about 0.5 to 1.5 parts by weight of amine was added to cure the aqueous two component modified with an acid monomer to increase mechanical properties. In addition, as a vulcanization accelerator, any of accelerators generally used in rubber can be used. However, since latex itself has a Michel structure and is dispersed in water, it is slow in reactivity, so that a strong accelerator is used. good. As such accelerators, accelerators such as thiazole, thiuram, and dithio carbamate are useful. Preferably, about 0.5 to 1.5 parts by weight of an accelerator of a thiazole type having good dispersion state and strong acceleration is used. In order to shorten the process time and increase the physical properties due to the synergistic effect, the dithiocarbamate system is preferably used in combination with 1 to 2.5 parts by weight.

And anti-aging agent added to reinforce the heat resistance and weather resistance of the binder may be amine-based, reaction products of amines and ketones, phenol-based, etc., but considering the anti-aging, molding (Blooming), pollution resistance, etc. after molding It is preferable to use a phenolic anti-aging agent in the quantity of 0.5-1.5 weight part. When using the above additives, the use outside the range of the chain is undesirable because it causes a decrease in the mechanical properties of the binder, a decrease in storage stability, a prolonged molding time, an increase in price, and the like.

In the case of treating the ground rubber particles using the binder according to the present invention, the mixing ratio thereof is 70 to 90 parts by weight: 10 to 30 parts by weight, preferably 80 to 90 parts by weight: 10 of the grinding rubber particles: binder. It is good to exist in the range of -20 weight part. When the binder is used in an amount of 10% by weight or less, sufficient wettability of the ground rubber particles and the binder is insufficient, and an unmolded part is likely to occur, and when used in an amount of 30% by weight or more, the appearance of the molded article is rather deteriorated.

The ground rubber particles which can be treated using the binder of the present invention include waste tire rubber ground particles, ethylene-propylene-diene terpolymer ground particles, and the like, and their particle diameters range from 0.3 mm to 2.0 mm. Can be in.

Hereinafter, the present invention will be described in more detail with reference to Examples. In each example, the units are parts by weight unless otherwise noted.

[Examples 1,2,3]

As the aqueous 1 and 2 components, styrene-butadiene latex having a total solid content of about 69% and 50% was used, respectively. The aqueous 1 component used a styrene and butadiene content ratio of 30/70 (weight ratio) and a solid content of 69%. The aqueous two component was modified by about 30% by methyl methacrylate, the content ratio of styrene and butadiene is 50/50 (weight ratio), and the solid content is 50%.

Various additives use bentonite in an amount of 2 to 7 parts by weight, or 25% by weight of 20% potassium oleate, of sodium salt of a condensate of alkyl naphthalene sulfonic acid and formalin as an emulsifier, and to prevent sedimentation during storage of the additive. 1 to 2 parts by weight, or 28% ammonia water in an amount of 1 to 25 parts by weight, mixed with water, and milled for 0.5 to 72 hours in a ceramic ball mill rotating at 100 to 150 rpm. Milling) was used to prepare an emulsion dispersion of the appropriate concentration.

And in order to produce a binder according to the present invention, a water-based one component and two components are respectively mixed in an amount of 30 parts by weight and 70 parts by weight, and then mixed with various additives shown in Table 1 and then rotated at 300 to 700 rpm A binder was prepared by mixing in a stirrer for 15 minutes. In order to measure the physical properties in the actual product, the waste tire rubber particles having an average particle diameter of about 1.3 mm are used in an amount of 90% by weight (based on the total weight of the rubber particles and the binder) and mixed with the binder evenly. It was vulcanized at 150 ° C. for 10 minutes using a press, and the physical properties of KS M 6518 vulcanized rubber were measured for physical properties.

[Examples 4, 5, 6]

The mixing ratio of the aqueous one component and the two components was carried out as indicated in Table 1 below, and the binder was prepared and used as shown in Examples 1 to 3 above. In order to measure the physical properties of the actual product, the vulcanized ethylene-propylene-diene terpolymer rubber particles crushed to an average particle diameter of about 1.3 mm were used in an amount of 90% by weight (based on the total weight of the rubber particles and the binder). The mixture was uniformly mixed with the binder and then vulcanized at 150 ° C. for 10 minutes using a hydraulic press, and the physical properties were measured using the KS M 6518 Vulcanized Rubber Physical Test Method.

Examples 7-10

A binder prepared in the same manner as in Examples 1 to 3 was used. And in order to measure the performance in the real product, the vulcanized ethylene-propylene diene terpolymer micro rubber powder ground to an average particle diameter of about 0.4 mm was used in an amount of 85% by weight (based on the total weight of the rubber powder and the binder). After homogeneously mixing with the binder was quenched for 10 minutes at 150 ℃ using a hydraulic press and the physical properties of the KS M 6518 vulcanized rubber was referred to the physical test method.

One 2 3 4 5 6 (comparative) 7 8 9 10 (comparative) Water system 1 ^* 30 30 30 20 40 60 30 30 30 0 Water system 2 ^** 70 70 70 80 60 40 70 70 70 100 zinc oxide 5.0 5.0 5.0 5.0 5.0 5.0 3.0 3.0 3.0 5.0 Phenolic Antioxidant ^*** 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Triethylamine 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 Ethylenediamine 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 55% Zinc Diethyl Dithiocarbamate 2.0 1.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 45% Sodium Dibutyldithiocarbamate 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.0 1.0 0.0 Zinc salt of 50% 2-mercaptobenzothiazole 0.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 60% sulfur 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Hardness (JIS A) 62 62 64 65 65 63 72 72 72 68 Elongation (%) 143 166 178 117 124 94 190 210 180 104 Tensile Strength (㎏f / ㎠) 21.3 24.9 28.9 27.4 26.8 18.5 26.4 31.8 26.9 22.4 *) KSL 341 ^R , Kumho Petrochemical Co., Ltd. **: KSL 203 ^R , Kumho Petrochemical Co., Ltd. **: Nobang SP ^R , Kumho Monsanto Co., Ltd.

The binder of the present invention as described above has the advantage of excellent bonding strength with the ground rubber particles and low cost.

Claims (6)

A binder of pulverized rubber particles, comprising the aqueous one component of the following (1) and the aqueous two component of the following (2). (1) styrene-butadiene latex having a butadiene content of 50% or more; (2) Styrene-butadiene latex modified at least 30% by acid monomer and having a styrene content of at least 30%. The binder of crushed rubber particles according to claim 1, wherein the amount of the one aqueous component is 10 to 50 parts by weight, and the amount of the two aqueous components is 50 to 90 parts by weight. 3. The compound according to claim 1 or 2, selected from the group consisting of 1 to 3 parts by weight of sulfur, 0.5 to 1.5 parts by weight of thiazole vulcanization accelerator, and 1 to 2.5 parts by weight of dithiocarbamate type accelerator. The binder further contains a mixture, and these additives are emulsified and dispersed in water at 40 to 70 wt%. 4. The binder of crushed rubber particles according to claim 3, further comprising an amine in an amount of 0.5 to 1.5 parts by weight. A method for treating and recycling ground rubber particles with a binder, the method comprising mixing 70-90 parts by weight of ground rubber particles with 10-30 parts by weight of the binder according to claim 1. 6. The method according to claim 5, wherein the crushed rubber particles are crushed rubber particles of a waste tire or crushed rubber particles of an ethylene-propylene-diene terpolymer, having an average particle diameter in the range of 0.3 mm to 2.0 mm.