JPH01301736A - Antiblocking agent for rubber and use thereof - Google Patents

Abstract

PURPOSE:To obtain an antiblocking agent for industrial rubber product, usable without causing dust generation, effective in improving antiblocking property of unvulcanized rubber and giving a rubber product uniformly attached with small amount of the antiblocking agent, by dispersing PE resin powder, etc., and hydrogenated wax resin powder in an aqueous solution of a nonionic surfactant. CONSTITUTION:The objective antiblocking agent can be produced by dispersing (A) preferably 5-30wt.% of powder of PE resin and/or PE wax resin (preferably having a melting point of <=150 deg.C and an average particle diameter of <=50mum) and (B) preferably 1-10wt.% of a hydrogenated wax resin powder (preferably a castor wax having a melting point of >=70 deg.C and an average particle diameter of <=50mum) in (C) an aqueous solution of a nonionic surfactant (preferably having an HLB of 3-18).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an anti-adhesive agent for industrial rubber products and a method of using the same. More specifically, it relates to a water-dispersible anti-stick agent for rubber that improves appearance change, adhesive performance, etc. of the final rubber product when applied to rubber products such as rubber footwear, rubber plates, and gaskets, and methods for using the same. It is something.

[Prior art] Conventionally, in the production and processing process of industrial rubber products, in the case of unvulcanized rubber such as rubber footwear, rubber plates, and packings,
Various anti-adhesive agents are used to prevent rubber from sticking to each other during storage, or when the rubber is stored stacked on top of each other until the next step.

To prevent this adhesion, rubber factories use inorganic powders such as talc, mica, and lucium carbonate as anti-adhesion agents for rubber.
Alternatively, powdered metal soap such as zinc stearate is applied to the rubber surface. In recent years, it has also been practiced to disperse these anti-adhesive agents for rubber in an aqueous surfactant solution, dilute the solution, and then apply the diluted solution to the rubber surface.

[Problems to be Solved by the Invention] However, when these powders are used, there are problems with the process due to dust generation when removing excess powder, and problems with occupational safety and health.

In addition, in the production and processing process of industrial rubber products such as rubber footwear, rubber plates, and packing, there are cases where the powdered rubber surface becomes the surface of the final product, and when rubber is mixed with rubber, rubber with cloth, and rubber with metal. These powders also pose a serious hindrance when it is necessary to carry out bonding processes between fibers.

For this reason, when performing lamination processing, etc., inorganic powders such as talc, mica, and calunium carbonate are applied thinly and uniformly to the rubber surface, and the excess powder is removed.

However, once the inorganic powder has adhered to the rubber surface, it cannot be sufficiently removed, so that the adhesion strength is lowered due to the detachment of the powder during the bonding process. In addition, mold contamination may occur due to adhesion of powder that has fallen off from the molding surface.

In addition, in the case of metal soaps such as zinc stearate, there is discoloration or white flaking on the surface of the vulcanized rubber.
However, it has the disadvantage of causing problems with the appearance of the product.

As a countermeasure against these dust particles, inorganic powders or powdered metal soaps are dispersed in an appropriate surfactant aqueous solution to form a water-dispersible anti-adhesive agent, and this is diluted with water and sprayed onto the rubber surface. Anti-adhesion treatment is carried out by passing a rubber material through a bath containing such a dispersion.

However, even with these methods, the condition of the rubber surface after moisture drying is somewhat improved compared to applying powder alone, but as long as inorganic powder or powdered metal soap is used, It is not possible to improve the appearance performance of the final product as described above.

The purpose of the present invention is to prevent powder adhering to the rubber surface of an unvulcanized rubber sheet from falling off in the production and processing process of industrial rubber products, and in addition, there is no mold contamination, and there is no discoloration or change in appearance for a long period of time. An object of the present invention is to provide a novel anti-stick agent for rubber that enables the production of rubber products, and a method for using the same.

Means for Solving Problem E] In order to achieve the above object, the present invention provides polyethylene resin and/or polyethylene wax resin powder ((a)
component) and hydrogenated wax resin powder (component (b)),
Nonionic surfactant with HLB of 3 to 18 (component (C))
It is dispersed in an aqueous solution to make a rubber anti-adhesion agent, and its proportions are 5 to 30% (by weight) of polyethylene resin and/or polyethylene wax resin powder, 1 to 10% (by weight) of hydrogenated wax resin powder, and non-stick powder. Ionic surfactant 1~
It is 10 (weight)%.

In the production and processing process of industrial rubber products, unvulcanized rubber sheets such as rubber footwear, rubber plates, and packing materials are used.
Use by applying it to the rubber surface.

The resin powder of component (a) used in the present invention is low molecular weight polyethylene or polyethylene wax sized to an average particle size of 50 μm or less at a melting point of 150°C or lower, preferably in the range of 80 to 150°C. . Its molecular weight is
It is about 500 to 3000. These resins are
Its molecular weight is between that of polyethylene resin and paraffin wax, and its properties are not intermediate in proportion to molecular weight; it has a high melting point, is extremely hard without flattening when solidified, and is vulcanizable. Temperature (80'
C or higher) and exhibits the unique property of being well compatible with rubber.

The average particle diameter may be 50μ or less, preferably 10 to 30μ. If it is larger than 50 μm, it is not preferable because powder easily falls off.

The resin powder as the surface component used in the present invention has a melting point of 70
It is a hydrogenated wax with a temperature above ℃.

In particular, castor wax, which is hardened by hydrogenating castor oil, is preferred because it has good compatibility with rubber. Moreover, it has been found that this castor wax has the effect of preventing the rubber from sticking to the roll during the rubber kneading process and further preventing the rubber from sagging.

The average particle diameter may be 50μ or less, preferably 10 to 30μ. If it is larger than 50 μm, it is not preferable because powder easily falls off.

In addition, in the present invention, the above-mentioned resin powders (a) and (b)
) The average particle diameter of the component was the median diameter (50% diameter) in a particle size-weight distribution diagram measured by the light transmission method of a centrifugal sedimentation type particle size distribution analyzer.

The nonionic surfactant (C) component contained in the anti-stick agent for rubber of the present invention includes polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, Glycerin fatty acid esters, polyoxyethylene fatty acid esters, fatty acid glycerides, etc. include those with an HLB of 3 to 18.

One type of polyoxyethylene alkyl ether type or a combination of two or more types with an HLB in the range of 6 to 4 is suitable as a material that exhibits the dispersion effect of organic resin powder in a relatively small amount. A combination of oxyethylene stearyl ether is preferred.

In the present invention, the amount of the resin powder <ω, component (b) used per 100 parts by weight of the rubber anti-stick agent of the present invention is as follows:
Component (a) is 5 to 30 parts by weight. If it is less than 5 parts by weight, a sufficient adhesion prevention effect cannot be obtained, and if it exceeds 30 parts by weight, powder tends to fall off, which is not preferable. When the amount is 5 parts by weight or more, a film of the (cL) component is formed on the rubber product after vulcanization, which improves weather resistance, which is preferable.

The amount of component (b) is 1 to 10 parts by weight. If it is less than 1 part by weight, a sufficient roll adhesion effect cannot be obtained, and if it exceeds 10 parts by weight, the appearance of the white rubber product tends to yellow, which is not preferable.

The amount of the nonionic surfactant (C) component used is 1 to 10 parts by weight, preferably 2 to 5 parts by weight.

If it is less than 1 part by weight, the resin powder tends to condense and separate;
If it exceeds 0 parts by weight, the rubber surface tends to become sticky, which is not preferable.

A method for manufacturing rubber footwear using the anti-stick agent for rubber of the present invention is carried out as follows.

An unvulcanized rubber dough sheeted out using a conventional rolling mill is coated with a diluted aqueous solution of the anti-stick agent for rubber of the present invention on the rubber surface by a method such as spraying, rolling, or dipping, and then dried. After drying, it is cut into a predetermined size and laminated between rubber and rubber and between rubber and cloth. Next, each processed part is vulcanized in a predetermined vulcanizer using hot air vulcanization, direct vulcanization, or press vulcanization to produce rubber footwear.

[Function] The water-dispersible anti-adhesive agent of the present invention comprising the above-mentioned components is stable during storage and dilution with water, has good workability, and can be coated uniformly on the rubber surface after anti-adhesive treatment. It is possible.

Further, with the anti-adhesive agent of the present invention, when unvulcanized rubbers are stacked on top of each other, there is no adhesion and no powder falls off. In addition, since each component particle has good compatibility with rubber, adhesive strength is improved during lamination processing, and the appearance of the final product is also improved.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 to 5 Rubber soles and tape rubber for rubber footwear were produced by rolling out sheets using a conventional rolling mill, and the following evaluations were carried out.

The anti-adhesive compositions not shown in Table 1 below were prepared as follows. Note that each composition ratio indicates parts by weight.

That is, first, two or more polyoxyethylene stearyl ethers with different HLBs are combined to reduce the HLB to 11.
Polyethylene wax with a melting point of 1.05°C and an average particle size of 30μ and castor wax with a melting point of 85°C and an average particle size of 10μ are dissolved in water, and An anti-adhesion agent solution was prepared by diluting it with twice the amount of water.

Next, the above anti-adhesion agent preparation was applied by dip coating onto the surface of the produced sheet-like unvulcanized rubber fabric and dried. After drying, it is cut to the desired size of the rubber sole, and then a rubber tape is attached and molded. Thereafter, 50 pairs of rubber footwear were produced by hot air vulcanization according to a conventional method.

In the processing process of the rubber footwear produced in this way, dust resistance, slipperiness, anti-adhesiveness, lamination and roll adhesion resistance were measured before vulcanization, and product appearance was measured after vulcanization. , the discoloration property and the adhesive strength between rubber cloths were measured.

Comparative Examples 1 to 3 Comparative Examples 1 to 3 are anti-adhesive compositions of the present invention in which 1 excludes castor wax and 2 excludes polyethylene wax. No. 3 uses a 325 mesh pass product of zinc stearate.

Comparative Examples 4 to 6 Among Comparative Examples 4 to 6, 4 used polyethylene wax, 5 used castor wax, and 6 used zinc stearate, each individually powdered.

The methods of each test in Examples and Comparative Examples are as follows.

Properties ■ Storage stability was determined by visual inspection of the presence or absence of separation after 30 days.

(2) Dilution separation stability was determined by diluting with 3 times the amount of water and visually observing the presence or absence of separation 7 days later.

Before Vulcanization ■ Dust property was determined by applying a predetermined amount of air to the surface of the rubber sheet on the 7th day after unvulcanized rubber sheeting, and visually determining the presence or absence of powder scattering.

■ Sliding property was determined by overlapping unvulcanized rubber sheets and determining the difficulty of slipping property when one rubber sheet was pulled in the lateral direction.

(2) For the anti-adhesive power, a test piece of 5 x 5 cm of unvulcanized rubber sheet rolled out to a thickness of 3 to 4 mm is immersed in an anti-adhesive adjustment solution diluted 3 times and dried.

After drying, overlap the two test pieces and mark it/rr? A load of 100% was applied and the sample was left in a constant temperature bath at 10°C for 24 hours. After being left standing, the force required for peeling was measured using an autoshopper type peel tester.

The anti-adhesive power is expressed as an index with Comparative Example 3 set as 100.

■ Lamination moldability refers to the workability when cutting the unvulcanized rubber sheet 1 to the specified size of the rubber sole, then laminating tape rubber and molding it.

■ Roll anti-stick property is 10 when rolled at 70-80℃.
After heating for a minute, the rubber was cut and peeled from the roll with a rubber knife, and the tackiness was evaluated.

After vulcanization ■ Product appearance is 60% in a vulcanization can at 120-130°C.
After hot air vulcanization for 30 minutes, the presence or absence of "white blur" on the black rubber surface was visually determined after 30 days.

(2) Discoloration was determined by visually observing the presence or absence of a "yellow tint" on the surface of the white rubber after 60 minutes of hot air vulcanization in a 120 to 130 DEG C. vulcanization can.

[Co., Ltd.] To measure the adhesive strength between rubber fabrics, apply a rubber adhesive to the surface of an unvulcanized rubber sheet that has been treated to prevent adhesion and the surface of a cotton fabric, and then bond both surfaces together after drying. Next, after hot air vulcanization for 60 minutes in a vulcanizing can at 120 to 130°C, the adhesive strength between the rubber and cotton fabric was determined based on JIS-6301 (7, peel test), using an index with Comparative Example 3 as 100. show.

The results are shown in Table 1.

As shown in Table 1, the water-dispersible anti-adhesive agent of the present invention has good storage safety and resin powder dispersion stability, and can be applied uniformly for anti-adhesive treatment. In addition, the dust problem is solved, the anti-adhesion property is improved, and the roll adhesion prevention effect of the return rubber is exhibited.

In the vulcanization process, there is no mold contamination, a polyethylene film is formed, and a rubber product with a glossy appearance is obtained.Furthermore, there is no discoloration, and the adhesive strength of the bonded area is improved. It will be done.

[Effects of the Invention] The anti-stick agent for rubber and the method for using the same of the present invention are extremely effective as they exhibit excellent effects as listed below.

(I) The problem of dust generation will be resolved and the working environment will be improved.

(II) The anti-adhesion properties of unvulcanized rubber are improved.

[Phase] The amount of adhesion preventive agent is uniform and small, and it is well compatible with rubber, improving adhesive strength.

Pox Prevents whitening of the final rubber product and maintains good appearance and stability over a long period of time.

(V) The problem of discoloration over time due to sunlight and heat after vulcanization is resolved, and the appearance of the product is improved.

Even when the return rubber is kneaded, it does not stick to the roll and prevents the rubber dough from sagging, which improves the thickness of the dispensed sheet and stable workability.

■ Because it has good compatibility with rubber, powder does not fall off the molding surface and does not contaminate the mold.

■ A polyethylene film is formed on the surface of the final rubber product, providing good gloss that lasts for a long time.

Claims (1)

[Scope of Claims] 1) An anti-stick agent for rubber, characterized in that polyethylene resin and/or polyethylene wax resin powder and hydrogenated wax resin powder are dispersed in an aqueous solution of a nonionic surfactant. 2) The anti-stick agent for rubber according to claim 1, wherein the polyethylene resin and/or the polyethylene wax resin powder both have a melting point of 150°C or less and an average particle size of 50μ or less. 3) The hydrogenated wax resin powder has a melting point of 70°C or higher,
The anti-adhesive agent for rubber according to claim 1, which is castor wax having an average particle size of 50 μm or less. 4) The anti-adhesive agent for rubber according to claim 1, wherein the nonionic surfactant has an HLB of 3 to 18. 5) 5 to 30% (by weight) of polyethylene resin and/or polyethylene wax resin powder, 1 to 10% (by weight) of hydrogenated wax resin powder, 1 to 10% (by weight) of nonionic surfactant, and the balance The anti-adhesive agent for rubber according to claim 1, wherein is water. 6) 5 to 30% (by weight) of polyethylene resin and/or polyethylene wax resin powder having a melting point of 150°C or less and an average particle size of 50μ or less, and castor having a melting point of 70°C or more and an average particle size of 50μ or less Claim 1 consisting of 1 to 10% (by weight) of wax resin powder and 1 to 5% (by weight) of a nonionic surfactant having an HLB of 3 to 18.
Anti-adhesion agent for rubber as described. 7) In the production and processing process of industrial rubber products, claims 1, 2,
A method of applying and using the rubber anti-adhesive agent described in 3, 4, 5, or 6.