JP2013159690A - Diene powder composition, method for producing the same, and diene rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powdery diene powder composition which is easy to transport or handle, and can adjust physical properties even when it is made into a solid rubbery diene rubber composition.SOLUTION: A diene powder composition is obtained by suspension-polymerizing 100 pts.mass of a dicyclobutadiene monomer in the presence of 0.5-30 pts.mass of a non-ionic surfactant followed by filtering and drying. A monomer to be polymerized may includes, relative to 100 pts.mass of the dicyclobutadiene monomer, 0.5-20 pts.mass of a monomer copolymerizable therewith, and the non-ionic surfactant is preferably a polyvinyl alcohol having a polymerization degree of 200-3,000 and a saponification degree of 70-95%.

Description

The present invention relates to a method for producing a diene-based powder composition. Moreover, it is related with the characteristic of the diene rubber composition which mix | blended this diene type powder composition.

Examples of the diene rubber composition having a dichlorobutadiene polymer include those obtained by mixing a latex of a dichlorobutadiene polymer and a polychloroprene latex (see, for example, Patent Document 1), and a monomer previously polymerized. Known are those obtained by copolymerization in the presence of a dichlorobutadiene monomer and a chloroprene monomer in a polymerization solution (for example, see Patent Document 2).
The technique described in Patent Document 1 can arbitrarily adjust the physical properties of the resulting diene rubber composition according to the solid content concentration and the addition ratio of the latex. However, when the obtained latex is made into a solid rubber, a conventional freeze-drying process must be performed, which increases the equipment. Further, since it is in a latex (aqueous dispersion) state, it is difficult to transport and handle the product, and further, the physical properties cannot be finely adjusted after the solid rubber is formed.
Since the technique described in Patent Document 2 obtains a diene rubber composition by copolymerizing monomers, the diene rubber composition having the same composition cannot be reproduced depending on the polymerization conditions. In addition, as in the technique described in Patent Document 1, the physical properties cannot be adjusted after the solid rubber is formed.

JP 2006-207600 A JP 2010-006902 A

An object of the present invention is to obtain a powdery diene-based powder composition that can be easily transported and handled and that can adjust the physical properties of a solid rubber-like diene-based rubber composition.

That is, the present invention provides a diene powder obtained by subjecting 100 parts by mass of a dichlorobutadiene monomer to suspension polymerization in the presence of 0.5 to 30 parts by mass of a nonionic surfactant, followed by filtration and drying. It is a composition. The monomer to be polymerized may contain 0.5 to 20 parts by mass of a monomer copolymerizable with 100 parts by mass of the dichlorobutadiene monomer, and the nonionic surfactant has a polymerization degree of 200. It is preferable to be polyvinyl alcohol having a saponification degree of 70 to 95%. The median diameter of the resulting diene-based powder composition is preferably 10 μm or more and 500 μm or less. The obtained diene powder composition can be blended with a chloroprene polymer, an antioxidant, a metal oxide and a vulcanization accelerator to form a diene rubber composition. The diene powder composition is prepared by subjecting 100 parts by mass of a dichlorobutadiene monomer to suspension polymerization in the presence of 0.5 to 30 parts by mass of a nonionic surfactant, and filtering the resulting slurry solution. It can be obtained through a washing step of washing to obtain a wet cake and a drying step of drying the obtained wet cake to obtain a powder.

It is easy to transport and handle, and a powdery diene powder composition is obtained. The diene powder composition can be kneaded into a solid rubber-like diene rubber composition using a roll, a Banbury mixer, an extruder, or the like, and the physical properties of the diene rubber composition can be easily adjusted.

It is the photograph which image | photographed the surface state of the diene type powder composition obtained in Example 1 using the scanning electron microscope (Keyence Corporation 3D real surface view microscope VE-8800) at 100-times multiplication factor. It is the photograph which image | photographed the surface state of the diene type powder composition obtained in Example 1 at 1000-times multiplication factor using the scanning electron microscope (Keyence Co., Ltd. 3D real surface view microscope VE-8800).

Hereinafter, the present invention will be described in more detail. The following are examples of the present invention, and the scope of the present invention is not interpreted narrowly.

The diene-based powder composition is prepared by dissolving a nonionic surfactant in water and then subjecting the polymerization solution to which a monomer containing a dichlorobutadiene monomer and a polymerization catalyst are added to suspension polymerization, followed by filtration and drying. Is obtained. The dichlorobutadiene monomer is 2,3-dichloro-1,3-butadiene (hereinafter referred to as DC).

The monomer that can be copolymerized with DC is not particularly limited in terms of its type, and examples thereof include esters of acrylic acid such as methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, methacrylic acid, and the like. Esters of methacrylic acid such as butyl acid and 2-ethylhexyl methacrylate, and hydroxy (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxymethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate , 1-chloro-1,3-butadiene, butadiene, isoprene, ethylene, styrene, acrylonitrile and the like can be used, and two or more kinds can be used together as necessary.
For example, a vulcanization characteristic of a diene powder composition obtained by copolymerizing DC and methacrylic acid can be improved by kneading into a solid rubber-like diene rubber composition. When copolymerizing a monomer copolymerizable with DC, the copolymerization amount is preferably in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass of the dichlorobutadiene monomer. More preferably, it is 10 parts by mass. If the amount is less than 0.5 parts by mass, the diene-based powder composition cannot be imparted with the characteristics of the monomer to be copolymerized. When kneading a powder composition into a diene rubber composition, poor dispersion may occur.

The nonionic surfactant is added for the purpose of suppressing the viscosity of the polymerization solution from increasing during the polymerization, and further reducing the amount of fine coagulum that becomes a clog during filtration. Nonionic surfactants include, for example, polyvinyl alcohol (hereinafter referred to as PVA), polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene sorbitan ether, polyoxyethylene castor oil ether, and the like. Oxyethylene derivatives, sorbitan fatty acid esters such as sorbitan monostearate, sorbitan monolaurate, sorbitan monopalmitate, fatty acid esters of glycerol such as glycerol monostearate, glycerol monooleate, aliphatic alkanolamines, polyoxy Ethylene distyryl phenyl ether, polyoxyethylene tristyryl phenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene hydroxy Mention may be made of the border ether and the like. Among these nonionic surfactants, it is preferable to use PVA because the stability to heat is good and the reaction can be stably performed.

When PVA is used as the nonionic surfactant, it is not particularly limited, but those having a saponification degree of 70 to 95 mol% are preferable. More preferably, the saponification degree is 70 to 90 mol%, and still more preferably 70 to 80 mol%. Moreover, the thing of the range whose polymerization degree of PVA is 200-3000 is preferable. More preferably, the degree of polymerization is 1000 to 3000. If PVA is in this range, the polymerization operation can be performed stably, and the resulting slurry solution is excellent in stability and can be obtained at a high concentration and stable.

The addition amount of the nonionic surfactant is 0.5 to 30 parts by mass with respect to 100 parts by mass of all monomers to be polymerized. More preferably, it is 1-20 mass parts, More preferably, it is 5-15 mass parts. When the addition amount of the nonionic surfactant is less than 0.5 parts by mass, the emulsifying power is not sufficient, and agglomerates are likely to occur frequently during the polymerization reaction. On the other hand, when the amount exceeds 30 parts by mass, thickening may occur during the polymerization reaction, stirring may be inhibited, and abnormal heat generation may be caused.

Examples of the polymerization catalyst include inorganic peroxides such as potassium persulfate, organic peroxides such as ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, and diacyl peroxides. . As a polymerization catalyst, use of lauroyl peroxide is preferable for performing stable polymerization. The polymerization catalyst is preferably used in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of all monomers to be polymerized. More preferably, it is 0.1-3 mass parts, More preferably, it is 0.1-2 mass parts.

There is no particular limitation on the water to be used. For example, ion-exchanged water, distilled water, pure water, water treated with ultrafiltration or reverse osmosis membrane can be used. However, it is preferable not to include a substance that inhibits polymerization.

A nonionic surfactant solution in which a nonionic surfactant is dissolved in water is preferably subjected to deoxygenation treatment before adding a polymerization catalyst. If oxygen is present, the polymerization catalyst is deactivated, and it is necessary to add more polymerization catalyst than necessary. The deoxygenation method is not particularly limited, but bubbling with nitrogen is preferable. The bubbling time, flow rate, and the like may be appropriately adjusted according to the amount of the polymerization solution and the scale of the polymerization apparatus.

The polymerization temperature is preferably in the range of 0 to 75 ° C. for polymerization control. In order to perform the polymerization smoothly and safely, the polymerization temperature is particularly preferably 10 to 60 ° C.

The final polymerization rate is preferably 80% by mass or more, and more preferably 90% by mass or more.

The pH of the polymerization solution is acidic but can be freely adjusted with a pH adjuster, dilute hydrochloric acid, sodium hydroxide or the like. In view of the stability of the polymerization solution, the preferred pH is 2.0 to 10.0, and more preferably 4.0 to 9.0.

The polymerization apparatus only needs to be a reaction apparatus provided with a stirrer capable of arbitrarily controlling the stirring power, and the type and structure thereof are not limited, and a conventionally known tank reactor or the like can be used.

The agitation blade of the polymerization apparatus may be any as long as it is generally used in suspension polymerization, and the kind thereof is not limited, and a paddle blade, a fiddler blade, a turbine blade, or the like can be used. It is desirable to use paddle blades.

The baffle of the polymerization apparatus is not particularly limited as long as it is generally used in suspension polymerization, and it is preferable to use a pipe baffle (bar type), a finger type baffle, or the like.

The number of rotations of the stirring blade of the polymerization apparatus is not particularly limited, but it is preferable that the power required for stirring Pv = 0.05 or more and 1 or less.

In order to stop the polymerization of the monomer, the temperature of the polymerization solution may be 5 ° C. or lower, preferably 0 ° C. or lower. The waiting time until the polymerization activity is settled is 20 minutes or more, preferably 1 hour or more.

A slurry solution is obtained by suspension polymerization. The diene composition is obtained by filtering and washing the slurry solution with water. The method for filtering the slurry solution is not particularly limited, and for example, natural filtration, vacuum filtration, pressure filtration, centrifugal filtration, decantation, or the like can be used. Among these methods, centrifugal filtration is preferable because filtration efficiency is improved.

Since the nonionic surfactant is attached to the surface of the wet cake of the diene composition obtained by filtration, the nonionic surfactant is removed by washing with water. The washing time, the number of washings and the water used for washing are not particularly limited, and the washing time is preferably 1 hour or more and is preferably repeated 3 times or more. With regard to water, ion-exchanged water, distilled water, pure water, limit Water treated by filtration or reverse osmosis membrane can be used. Furthermore, it is more preferable that the washing time is 2 hours or more, and this is repeated 4 times or more.

The diene composition obtained by washing with water becomes a powdery diene powder composition by drying. There is no particular limitation on the drying method, and a shelf dryer, a gear oven, a vacuum dryer, a spray dryer, or the like can be used.

In the case of a shelf dryer, the drying temperature is preferably 30 ° C. or higher and 80 ° C. or lower, and more preferably 40 ° C. or higher and 70 ° C. or lower. Also, the moisture content after drying is preferably 5% or less, more preferably 2% or less.

Although the measuring method of the median diameter of the obtained diene type powder composition is not limited, For example, it can measure with a laser beam diffraction method, a phase Doppler method, a roller trap type vibration sieve, etc.

The median diameter of the diene-based powder composition is preferably adjusted to 10 μm or more and 500 μm or less. When the median diameter is within this range, the resulting diene powder composition is favorably dispersed in the diene rubber composition. In order to control the median diameter of the diene-based powder composition, the pH of the nonionic surfactant solution and the stirring power required for the stirring blade may be adjusted. To increase the median diameter of the diene-based powder composition In order to reduce the median diameter, the pH of the nonionic surfactant solution can be lowered or the stirring power required for the stirring blade can be reduced. To reduce the median diameter, the pH of the nonionic surfactant solution can be increased or stirred. What is necessary is just to enlarge the power required for stirring of a blade.

There are various methods for kneading the obtained diene-based powder composition into the chloroprene-based polymer, not particularly limited, and using a roll, a Banbury mixer or an extruder, the diene-based powder composition is an anti-aging agent, What is necessary is just to knead | mix similarly to a metal oxide, a vulcanization accelerator, etc.

Hereinafter, examples will be described in order to confirm the effects of the present invention. The diene-based powder composition was manufactured and its physical properties were confirmed, and the change in characteristics when the powder was fine and mixed with existing rubber was confirmed.

<Example 1>
[Production of Diene Powder Composition A]
Assemble a 6 L separable flask. At that time, a plate-like baffle with two baffle plates (width 2 cm × height 27 cm × thickness 0.1 cm) is incorporated. As the stirring blade, only the lower part of the full zone blade was used. The size of the stirring blade is 13 cm wide × 9 cm high × 0.1 cm thick.

Oxygen was removed by bubbling nitrogen through 100 parts by mass of DC for 30 minutes. After 30 minutes, 0.5 part by mass of lauroyl peroxide (hereinafter referred to as LPO) is dissolved in DC as a polymerization catalyst. This solution is called a monomer solution.

10 masses of PVA (MP-10R manufactured by Denki Kagaku Kogyo Co., Ltd .; volatile content 2.6 mass%, saponification degree 72.9 mol%, Na acetate 0.8%) as nonionic surfactant with respect to 580 mass parts of pure water Dissolve the parts. This solution is called a PVA solution.

The whole amount of the PVA solution is put into a separable flask, the stirring blade is rotated at 250 rpm, and the temperature is raised to 60 ° C. while bubbling nitrogen for 30 minutes.

Stirring is stopped when the heated PVA solution is stabilized at 60 ° C., and the monomer solution is added all at once. Hereinafter, this solution is referred to as a mixed solution.

The rotation speed of the stirring blade of the polymerization can containing the mixed solution is increased to 300 rpm, the temperature of the mixed solution is maintained at 60 ° C., and the reaction is performed for 2.5 hours. The reaction start time is defined as the time at which the monomer solution is added to the polymerization reaction start time.

The reaction is stopped after 2.5 hours and cooled with ice water for 60 minutes. After 60 minutes, the rotation of the stirring blade is stopped. The mixed solution after stopping the reaction is hereinafter referred to as a slurry solution.

The obtained slurry solution was subjected to centrifugal filtration, and the resulting diene composition wet cake was placed in a 5 L glass beaker. For washing with water, 4 L of pure water was added and stirred for 2.5 hours with a Teflon (registered trademark) anchor blade. This time, the operation of centrifugal filtration after washing with water for 2.5 hours was repeated four times, so that washing was performed for a total of 10 hours.

The obtained diene composition was dried at 40 ° C. for 72 hours using a shelf dryer.

As shown in FIGS. 1 and 2, the diene-based powder composition obtained by drying is obtained as secondary particles (average particle diameter: 72.4 μm) in which primary particles are aggregated. The particle size was calculated from the particle size distribution measured using a laser diffraction particle size distribution measuring device (SALD-3000S manufactured by Shimadzu Corporation).

The obtained diene powder composition was kneaded with a compound shown in Table 1 in a 1.7 L Banbury mixer (MS-1.7 closed automatic mixer manufactured by Yamashina Seiki), and the resulting rubber The dynamic viscoelasticity of the composition was measured. The mixing conditions in the 1.7 L Banbury mixer were such that the cooling water was 30 ° C., the rotation speed was 50 rpm, and the filling rate was 73%. In Table 1, rubber A is DCR-37 manufactured by Denki Kagaku Kogyo Co., Ltd., and rubber B is DCR-66 manufactured by Denki Kagaku Kogyo Co., Ltd. NOCRACK CD is an anti-aging agent manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., and commercially available products of SRF (carbon black # 50), stearic acid and MgO (# 30) were used.

The measurement method of the viscoelastic spectrum is JIS standard JISK6394 / vulcanized rubber and thermoplastic rubber-Determination of dynamic properties-General guidelines, E '(stored elastic modulus) and E''(loss) Elastic modulus). The method of calculating E ′ and E ″ is as follows.
-It is the value which calculated | required by E '= τ' / γ0, and divided | segmented the stress of the same phase as a distortion | strain with the distortion | strain.
-It is the value which calculated | required by E '' = (tau) '' / (gamma) 0, and remove | divided with the distortion | strain and the stress from which (pi) / 2 rad phase shifted | deviated.
• γ0 (maximum strain amplitude) is the maximum value of the half amplitude based on the average strain. • τ ′ is the stress in the same phase as the strain. • τ ″ is the stress that is out of phase with the strain by π / 2 rad.

As shown in Table 1, by kneading the diene-based powder composition, the viscoelastic spectrum E ′ at 23 ° C. was improved by 9.4% compared to Comparative Example 1 in which this was not added, and E ″ Improved by 7.5%. By kneading the diene powder composition A of the present invention, it was possible to improve the vibration isolation characteristics of the rubber A.
The improvement rate (%) of E ′ and E ″ is the improvement rate (%) calculated by the following formula = (value of Example 1−value of Comparative Example 1) / (value of Comparative Example 1) × 100

<Example 2>
The rubber A kneaded in Example 1 was changed to rubber B, kneaded in the same manner as in Example 1, and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 17.4% and E ″ was improved by 21.9% compared to Comparative Example 2 in which this was not added.

<Example 3>
[Production of Diene Powder Composition B]
A diene-based powder composition (median diameter 112.0 μm) was obtained in the same manner as in Example 1 except that the pH was adjusted to 4.0 with 1.0 mol% dilute hydrochloric acid when adjusting the PVA solution.

The obtained diene powder composition was kneaded in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 8.3% and E ″ was improved by 7.1% as compared with Comparative Example 1 in which this was not added.

<Example 4>
The rubber A kneaded in Example 3 was changed to rubber B, kneaded in the same manner as in Example 1, and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 16.1% and E ″ was improved by 17.2% compared to Comparative Example 2 in which this was not added.

<Example 5>
[Production of Diene Powder Composition C]
When adjusting the PVA solution, a diene powder composition (median diameter 12.3 μm) was prepared in the same manner as in Example 1, except that the pH was adjusted to 6.5 using a 1.0 mol% aqueous sodium hydroxide solution. Obtained.

The obtained diene powder composition was kneaded in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 9.7% and E ″ was improved by 7.7% as compared with Comparative Example 1 in which this was not added.

<Example 6>
[Production of Diene Powder Composition D]
A diene-based powder composition (median diameter of 480.4 μm) was obtained in the same manner as in Example 1 except that the pH was adjusted to 3.0 using 1.0 mol% dilute hydrochloric acid when adjusting the PVA solution.

The obtained diene powder composition was kneaded in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 7.2% and E ″ was improved by 5.3% as compared with Comparative Example 1 in which this was not added.

<Example 7>
[Production of Diene Powder Composition E]
When adjusting the PVA solution, a diene system was used in the same manner as in Example 1 except that the pH was adjusted to 6.5 using a 1.0 mol% aqueous sodium hydroxide solution and the required power for stirring Pv was 1.0. A powder composition (median diameter 8.9 μm) was obtained.

The obtained diene powder composition was kneaded in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 9.8% and E ″ was improved by 7.7% compared to Comparative Example 1 in which this was not added.

<Example 8>
[Production of Diene Powder Composition F]
When adjusting the PVA solution, the diene-based powder composition was the same as in Example 1 except that the pH was adjusted to 3.0 using 1.0 mol% dilute hydrochloric acid and the power required for stirring was Pv = 0.1. (Median diameter 520.3 μm) was obtained.

The obtained diene powder composition was kneaded in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 7.3% and E ″ was improved by 5.1% as compared with Comparative Example 1 in which this was not added.

<Example 9>
[Production of Diene Powder Composition G]
The diene powder composition (median diameter 68.5 μm) was the same as in Example 1 except that the monomer solution was adjusted by adding 95 parts by weight of DC and 5 parts by weight of methacrylic acid as a monomer to be copolymerized. )

The obtained diene powder composition was kneaded in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As shown in Table 1, E ′ was improved by 9.0% and E ″ was improved by 7.0% as compared with Comparative Example 1 in which this was not added.

<Comparative Example 1>
In this example, rubber A was kneaded without blending the diene powder composition in Example 1.

<Comparative example 2>
In this example, rubber B was kneaded without blending the diene powder composition in Example 2.

<Comparative Example 3>
Although not shown in the table, as a conventional method, after mixing the latex of rubber A and the latex of the diene composition at a ratio similar to that of Example 1, this was freeze-dried to obtain a rubber. Evaluation was performed by kneading in the same manner as in Example 1. E ′ improved by 9.6% and E ″ improved by 7.3%. That is, it can be said that Example 1 was able to realize the same performance as the rubber composition obtained by the conventional latex method by a simpler method.

<Comparative example 4>
This is an example in which the amount of PVA as a nonionic surfactant is 0.3 parts by mass when the diene-based powder composition in Example 1 is manufactured. Although not shown in Table 1, the resulting diene powder composition was coarsened and could not be uniformly kneaded into rubber A and rubber B.

<Comparative Example 5>
This is an example in which the amount of PVA as a nonionic surfactant is 40 parts by mass when the diene powder composition in Example 1 is manufactured. Although not shown in Table 1, the viscosity of the PVA solution became high, and DC could not be polymerized.

From the above, it was shown that DC can be formed as a powder and its particle size can be changed by changing the pH of the PVA solution and the power required for stirring of the stirring blades during monomer polymerization. When the obtained DC powder is kneaded with existing rubber, the viscoelastic spectrum increases, and a rubber having good vibration-proof characteristics can be produced.

Claims (7)

  A diene powder composition obtained by subjecting 100 parts by mass of a dichlorobutadiene monomer to suspension polymerization in the presence of 0.5 to 30 parts by mass of a nonionic surfactant, followed by filtration and drying.   The diene powder composition according to claim 1, wherein the monomer to be polymerized contains 0.5 to 20 parts by mass of a monomer copolymerizable with 100 parts by mass of the dichlorobutadiene monomer. object.   3. The diene powder composition according to claim 1, wherein the nonionic surfactant is polyvinyl alcohol having a polymerization degree of 200 to 3000 and a saponification degree of 70 to 95%.   The diene powder composition according to any one of claims 1 to 3, wherein the median diameter of the diene powder composition is 10 µm or more and 500 µm or less.   A diene rubber composition comprising the diene powder composition according to any one of claims 1 to 4 and a chloroprene polymer, an antioxidant, a metal oxide, and a vulcanization accelerator.   A polymerization process in which 100 parts by mass of dichlorobutadiene monomer is subjected to suspension polymerization in the presence of 0.5 to 30 parts by mass of a nonionic surfactant, and the obtained slurry solution is filtered and washed to obtain a wet cake. The manufacturing method of the diene type powder composition which has the washing | cleaning process to perform and the drying process which dries the obtained wet cake into powder.   6. The diene-based powder composition according to claim 5, wherein the monomer to be polymerized contains 0.5 to 20 parts by mass of a monomer copolymerizable with 100 parts by mass of the dichlorobutadiene monomer. Manufacturing method.