JPH0543744A - Wax-based aging preventing agent for preventing bloom of rubber surface - Google Patents

Abstract

PURPOSE:To obtain a wax based aging preventing agent for preventing bloom of wax without impairing static ozone resistance. CONSTITUTION:A wax based aging preventing agent for preventing bloom of rubber surface consisting of hydrocarbon wax, characterized by a composition in hydrocarbon wax in which (a) the content of >=58C straight-chain saturated hydrocarbon is 3-30wt.% and (b) the content of 48-57C straight-chain hydrocarbon is 3-30wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wax anti-aging agent which prevents blooming of the appearance of a rubber product without impairing the static ozone resistance of the rubber product.

[0002]

2. Description of the Related Art In recent years, there has been a demand for measures to prevent the deterioration of the appearance of a tire from white or brown due to blooming of an antiaging agent for a rubber material from the surface of a rubber product such as an automobile tire.

Wax-based antiaging agents are no exception, and in order to prevent wax from blooming, it is important to further improve static ozone resistance and simultaneously prevent blooming.

Generally, in order to improve the static ozone resistance of a wax type anti-aging agent, the number of carbon atoms contained in the wax can be found as disclosed in JP-A-1-230648, JP-B-49-45289 and JP-B-54-25061. There is a method of increasing the linear saturated hydrocarbons of 21 to 51, but such a method improves ozone resistance but cannot prevent bloom.

On the other hand, as a method for preventing the bloom of the wax type anti-aging agent, a high melting point wax such as microcrystalline wax, Fischer-Tropsch wax and low molecular weight polyethylene, which has an effect of reducing the bloom amount, is blended. However, since the ozone resistance is deteriorated, a rubber containing a large amount of wax is used, resulting in an increase in direct material cost.

[0006] Further, as a technique aimed at simultaneously improving the static ozone resistance of the wax type anti-aging agent and preventing bloom, there is a linear saturated hydrocarbon and a non-linear chain contained in the wax. Some have stated that it is necessary to select the ratio of both components of the saturated hydrocarbon in an appropriate range, but the sufficient effect cannot be achieved, and further improvement is required also from this point.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wax anti-aging agent which prevents wax bloom without impairing static ozone resistance, which was impossible with the prior art.

[0008]

As a result of intensive studies to solve the above problems, the present inventors have found that the composition of the wax-based antioxidant is a linear saturated hydrocarbon having 19 to 100 carbon atoms and a side chain. It is composed of a large number of hydrocarbon components such as saturated hydrocarbons, naphthenes, aromatics, etc. Among these components, the inhibitory substance that may reduce the ozone resistance of the wax anti-aging agent has 58 or more carbon atoms. It is necessary to find out that it is a straight chain saturated hydrocarbon, and to remove or significantly reduce this component, and the most effective component for preventing bloom of the wax-based antioxidant is a carbon number of 48-5.
It was also found that it is a straight chain saturated hydrocarbon of No. 7, and it was found that this component is required within a limited range, and it was found that the specific wax composition shown below overcomes the drawbacks of the prior art. The present invention has been completed.

That is, according to the present invention, in a wax-based antioxidant comprising a hydrocarbon wax, the composition of the hydrocarbon wax is: a) The content of linear saturated hydrocarbon having 58 or more carbon atoms is 1
A wax-based antioxidant for preventing modification of the rubber surface, characterized in that the content of the linear saturated hydrocarbon having 48 to 57 carbon atoms is 3 to 30% by weight. is there.

[0010]

The present invention has discovered the fact that static ozone resistance decreases when a linear saturated hydrocarbon having 58 or more carbon atoms is contained in a wax anti-aging agent within a limited range. Based on.

The composition of the wax anti-aging agent has 19 carbon atoms.
Up to about 100 linear chain saturated hydrocarbons, side chain saturated hydrocarbons, naphthenes, aromatics and the like. Of these, straight chain saturated hydrocarbons were used as pure products synthesized for each number of carbons, and were mixed in a wax to test the effect on static ozone resistance. As a result, as shown in Table 1, the carbon number was 54
Even if the linear saturated hydrocarbons up to 1 are contained in the wax anti-aging agent, the static ozone resistance is hardly changed, but if the linear saturated hydrocarbons having more than 54 carbon atoms are contained, the static ozone resistance is increased. It has been found that the static ozone resistance is drastically reduced when the property starts to deteriorate and a linear saturated hydrocarbon having 58 or more carbon atoms is contained. However, when the content of the linear saturated hydrocarbon having 58 or more carbon atoms contained in the wax anti-aging agent is substantially 1% by weight or less, the static ozone resistance is less likely to decrease. The allowable range can be limited. If it exceeds 1% by weight, the static ozone resistance is significantly deteriorated, which is not preferable. The above-mentioned phenomenon that the static ozone resistance is deteriorated remarkably appears in the temperature range of 30 to 50 ° C and is not observed at the temperature of 10 ° C.

Further, in order to prevent the bloom of the wax type anti-aging agent, if the content of the straight chain saturated hydrocarbon having 48 to 57 carbon atoms is 3 to 30% by weight, a sufficient bloom preventing effect is exhibited. I found out. As shown in Table 2, when a linear saturated hydrocarbon synthesized for each carbon number was blended with a wax and the effect on the amount of bloom was tested, a linear saturated hydrocarbon having a carbon number of 48 to 60 prevented a large bloom. Showed the effect. However, as described above, the linear saturated hydrocarbon having 58 or more carbon atoms significantly reduces the static ozone resistance, and therefore the linear saturated hydrocarbon having 48 to 57 carbon atoms is limited as the optimum component. Further, the amount of bloom decreases as the content of the linear saturated hydrocarbon having 48 to 57 carbon atoms contained in the wax-based antioxidant increases, but if the content of 48 to 57 carbon atoms is less than 3% by weight. The effect of preventing bloom is not sufficient, and the content rate of C48-57 is 3
If it exceeds 0% by weight, the bloom preventing effect reaches a ceiling and becomes almost constant. Therefore, not only is the content higher than this not necessary, but it is also not preferable because it reduces the components effective against static ozone resistance. ..

Therefore, the content of the straight chain saturated hydrocarbon having 48 to 57 carbon atoms is limited to 3 to 30% by weight.

Further, as shown in Comparative Examples described later, the non-straight chain hydrocarbon contained in the wax-based antioxidant does not have static ozone resistance even if its carbon number range and content are varied. It was also found that non-linear hydrocarbons are not an effective component as they have little effect on bloom prevention.

[0015]

[Table 1]

[0016]

[Table 2] As a method for producing the wax anti-aging agent of the present invention,
In order to significantly reduce the amount of bloom without deteriorating the static ozone resistance, high melting point waxes such as microcrystalline wax, Fischer-Tropsch wax and low molecular weight polyethylene are distilled under reduced pressure to obtain a straight chain having 48 to 57 carbon atoms. A high-melting-point wax that achieves both concentration of a saturated hydrocarbon component and reduction or removal of a linear saturated hydrocarbon component having 58 or more carbon atoms is prepared in advance. However, the distillation is not limited to vacuum distillation, and a solvent deoiling method, a sweating method, or a press deoiling method can also be used.

Next, the high melting point wax is blended with a wax anti-aging agent, and the final product is adjusted by high temperature capillary gas chromatography so as to have a desired composition.

The wax composition of the present invention is quantified by a gas chromatograph equipped with a capillary column. The gas chromatograph device is preferably one that separates linear saturated hydrocarbons up to 80 or more carbon atoms, and from the obtained gas chromatogram chart, the content rate of linear saturated hydrocarbons with 48 to 57 carbon atoms and 58 or more carbon atoms. The linear saturated hydrocarbon content of is determined.

[0019]

EXAMPLES Next, the present invention will be described more specifically by way of Examples and Comparative Examples. These are examples for helping understanding of the present invention, and the present invention is not limited thereto.

The numerical values described in Examples and Comparative Examples are
It was measured by the following method.

Composition analysis of wax: Measured by a gas chromatograph equipped with a capillary column.

Static ozone resistance (according to JIS K6301): A sheet after vulcanization is punched out with a JIS No. 1 dumbbell, and an ozone weather meter OMS manufactured by Suga Test Instruments Co., Ltd.
-1V, ozone concentration 100pphm, temperature 30 ~
The test was conducted under the conditions of 50 ° C. and an elongation rate of 10 to 50%. Regarding the crack generation state of the test piece, the elongation rate of the test piece having a crack at the smallest elongation rate was evaluated as the critical strain. The higher the number, the better.

Discoloration test of rubber appearance (bloom resistance test): Vulcanized sheet (size 145 × 145 × 2.3 m)
m) in a constant temperature drying bath at a temperature of 30 to 50 ° C., and 3
After leaving for 0 days, the wax that had been taken out and bloomed on the surface of the sheet was scraped off with a cutter knife, and the weight of the wax was measured. The lower the weight, the better.

[Examples 1 to 3] 10 kg of Fischer-Tropsch wax (manufactured by Sazol Corporation (South Africa), trade name "Sazol H.2") was placed in a centrifugal molecular distillation apparatus (manufactured by Nippon Sharyo Co., Ltd., model MS-380) And vacuum degree 0.0
A fraction was obtained by fractional distillation under the conditions of 02 mmHg, evaporating dish temperature 180 → 280 ° C., temperature interval 20 ° C., and flow rate 15 liter / hr. The fraction thus obtained is a commercially available wax-type antioxidant (manufactured by Nippon Seiro Co., Ltd., trade name "OZOACE")
And the wax-based antioxidant of the present invention was prepared by gas chromatography analysis. However, the effects of the invention can be compared under the same conditions by blending the linear saturated hydrocarbons having 21 to 47 carbon atoms contained in the waxes of Examples 1 to 3 so that the carbon number distribution becomes constant. I chose

NR / B shown in Table 3 by open roll
Using the R blending, the blending amount of the wax anti-aging agent of the present invention was 1.2 phr and 1.5 phr in the static ozone test, and 4.0 in the discoloring test of rubber appearance (bloom resistance test).
Each phr was blended and press-vulcanized at 160 ° C. for 20 minutes to prepare a vulcanized sheet.

The reason why the wax compounding amount is changed for each of the above test items is that severe conditions are selected so that the difference in performance between the waxes can be clearly shown in the test results.

The results of the static ozone resistance of each sheet and the color change test (bloom resistance test) of the rubber appearance are shown in Table 4 together with the properties of the wax anti-aging agent.

[Examples 4 to 5] Linear saturated hydrocarbons having 48, 50, 52, 54, and 56 carbon atoms synthesized for each carbon number (content of 95% or more by infrared absorption spectrum and gas chromatographic analysis, respectively) ) Each 20% by weight
Each was melt mixed. 48 to 5 carbon atoms obtained in this way
A mixture of straight-chain saturated hydrocarbon of 6 (content 95% or more) was used in the same manner as in Examples 1 to 3, and a commercially available wax-based antioxidant (manufactured by Nippon Seiro Co., Ltd., trade name "OZOACE").
The wax-based antioxidant of the present invention was prepared by using gas chromatographic analysis to prepare a vulcanized sheet.

Table 4 shows the test results and characteristics of Examples 4-5.

Comparative Examples 1 to 8 Comparative Example 1 is a commercially available wax-type antioxidant, manufactured by Nippon Seiro Co., Ltd., under the trade name "OZOA".
A vulcanized sheet was obtained in the same manner as in Example 1 except that "CE" was used alone.

Comparative Examples 2 and 8 are commercially available low molecular weight polyethylenes having melting points of 86 ° C. and 102 ° C., Comparative Example 3 is Examples 4 and 5.
A mixture of straight-chain saturated hydrocarbons having a carbon number of 48 to 56 (content of 95% or more) when prepared above, Comparative Examples 4 and 5 are commercially available petroleum microcrystalline waxes having melting points of 84 ° C. and 89 ° C., Comparative Example 6 Commercially available Fischer-Tropsch waxes having melting points of 88 ° C. and 95 ° C. were mixed with the wax anti-aging agent in the same manner as in Examples, to prepare vulcanized sheets.

Table 4 shows the test results and characteristics of Comparative Examples 1 to 8.

Each of Examples 1 to 5 is an example satisfying the components and the content rate specified in the present invention, that is, having 5 carbon atoms.
Since the content of the linear saturated hydrocarbon having 8 or more is 1% by weight or less, the static ozone resistance does not decrease, and the content of the linear saturated hydrocarbon having 48 to 57 carbon atoms is 3 to. Three
Comparative Example 1 is an improved product that realizes a technology that is also excellent in the bloom prevention effect due to 0% by weight.
It can be seen by comparison with ~ 8. In Comparative Examples 1 to 8, a conflicting relationship is established between the prevention of static ozone resistance deterioration and the prevention of bloom.

[Comparative Examples 9 to 14] Three types of petroleum paraffin waxes having different melting points-melting points 55.3 ° C, 69.3 ° C, 7
Non-linear saturated hydrocarbon components (non-normal content of 85% or more) and two types of petroleum microcrystalline wax separated from 6.7 ° C by the molecular sieve 5A method-
The same components (non-normal content 90% or more) separated from the melting points of 71.7 ° C. and 89.2 ° C. by combining the solvent deoiling method and the molecular sieve 5A method were used as a wax type antiaging agent in the same manner as in Examples. Table 5 shows the results of blending and forming a vulcanized sheet, and examining the influence of the non-linear saturated hydrocarbon component contained in the wax on the static ozone resistance and bloom resistance test. As can be seen, regardless of the content of the non-linear saturated hydrocarbon component contained in the wax anti-aging agent and the type of raw wax before separating the component, the component has static ozone resistance and bloom prevention. It has been found that the effect on the product is small and it is not an effective component.

[0035]

EFFECT OF THE INVENTION When the wax composition for preventing modification of the rubber surface according to the present invention is used as a wax-based antiaging agent in a rubber product, the antiaging agent blooms from the surface of the rubber product such as an automobile tire and the rubber surface appears. It is excellent in preventing discoloration, and can be improved without lowering static ozone resistance.

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 14, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

[0036]

[Table 3]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

[0039]

[Table 6]

Claims (1)

[Claims] 1. A wax-based antioxidant comprising a hydrocarbon wax, wherein the composition of the hydrocarbon wax is a) the content of linear saturated hydrocarbon having 58 or more carbon atoms is 1
A wax-based antioxidant for preventing modification of the rubber surface, characterized in that the content of the linear saturated hydrocarbon having 48 to 57 carbon atoms is 3 to 30% by weight.