JPS61120803A - Production of rubber masterbatch - Google Patents

Abstract

PURPOSE:To produce a rubber masterbatch having uniformly dispersed filler and high quality in high efficiency of production, by simultaneously performing the kneading of a rubber solution with a filler and the removal of a solvent by using an extruder having a vent mechanism. CONSTITUTION:A rubber solution (of a rubber concentration of about 10-70wt%) is kneaded with additives such as a filler, reinforcement, plasticizer, lubricant and crosslinking agent by using an extruder having a vent mechanism. For example, a unidirectional twin-screw extruder 1 equipped with three vents is used, and a rubber solution sent from a material tank 5 through a material feeder 7 is fed to the heating/mixing zone 14 of the barrel. A filler sent from an additive tank 6 through an additive feeder 8 is fed to a position near the feed point of the rubber solution. It is desirable that a powdered filler is slurried into a slurry of fine particles by a homogenizer 18. The solvent vapor generated in the extruder as the kneading proceeds is aspirated through vents 11, 12 and 13 by sources of vacuum 9 and 10. In order to obtain a high-quality rubber masterbatch, it is desirable that the temperature of the dried product is de creased and the vacuum in the system is heightened to the greatest possible degree.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a rubber masterbatch, and more particularly to a method for efficiently producing a high-quality rubber masterbatch in which fillers are uniformly dispersed.

Rubber masterbatch is consumed in large quantities due to energy saving, labor saving, and work environment protection during rubber processing, and the consumption is on the rise.

(Prior Art) As a method for producing synthetic rubber, there is a method of synthesizing rubber by carrying out polymerization reaction, addition reaction, substitution reaction, etc. in an organic solvent system.

As a method for producing a comb master patch from the rubber obtained by these reactions, the rubber is recovered from the rubber solution and made into a solid rubber, and then the rubber and the filler are mixed using a powerful machine such as an internal mixer or a mixing roll. The so-called tri-blend method is used in which a rubber masterbatch is prepared using a kneader. These techniques are routinely practiced in this industry and have become common knowledge (for example, the Japan Rubber Association's "Rubber Industry Handbook (New Edition)" (1974-8-1) -1
, 5) Japan Rubber Association P449-45'7).

(While the invention is trying to solve the problem, the triblend method as a rubber masterbatch manufacturing method is as follows: (1) A powerful kneading machine is required, resulting in high cost.

(2) Excessive shearing during kneading tends to cause deterioration of physical properties due to heat generation.

(3) The work environment deteriorates due to the generation of dust particles etc. due to the filling material, and equipment and costs are required for improvement.

There are also problems such as this, and there is a strong demand for improvement from the viewpoint of productivity and uniformity of quality. The present inventor investigated a method for efficiently obtaining a high-quality rubber masterbatch by eliminating the problems of the prior art.

(Means to Solve the Problem) As a result of various studies on how to efficiently obtain a high-quality rubber masterbatch, the inventor of the present invention kneaded the rubber solution and the filler using an extruder with a devolatilizing function. The present inventors have discovered that a rubber masterbatch with excellent dispersibility can be produced by performing both the evaporative removal of the solvent and the evaporative removal of the solvent in the same device, and have thus arrived at the present invention.

That is, the present invention is a method for producing a rubber masterbatch characterized by using an extruder having a devolatilization function to mix a rubber solution and a filler, and performing kneading and solvent removal in the same device. .

The comb solution as used in the present invention includes a rubber solution in which the comb is dissolved in a solvent or partially dispersed, such as in a rubber containing kale.

The compositions are chlorosulfonated polyolefin, SBJ.
BREPDM, etc., and the solvent that can dissolve the comb is a so-called organic solvent that can dissolve the rubber (including a partially dispersed state) and is volatile, although it differs depending on the type of target rubber. Specific examples include halocenide hydrocarbons such as carbon tetrachloride and chloroform, aromatic hydrocarbons such as henzene toluene and xylene, aliphatic hydrocarbons such as butane, botan, and hegizan octane, and There is carbon sulfide.

These rubber solutions can be obtained by dissolving solid rubber, but
Usually, it is obtained as a pre-process for solid rubber production when rubber is synthesized in a solvent.

Although the concentration of rubber in the rubber solution is not particularly limited, a high concentration is preferable from the viewpoint of solvent removal. However, as the concentration increases, the viscosity of the solution increases exponentially.
This will impede the handling of the solution. Although it varies depending on the type of rubber solution, a rubber concentration of about 10 to 70% by weight can be preferably used.

The term "rubber masterbatch" as used herein refers to a rubber compound obtained by mixing part or all of the amount of rubber and/or compounding agents that should be present in the final compounded rubber.

The term "filler" as used in the present invention is a general term for compounding agents used in the COMBUSTER Patch. The type of filler varies depending on the desired final compounded rubber, but main examples include fillers such as calcium carbonate and Kuhetalc, reinforcing agents such as carbon black and silicic acid, DBP, DOP,
DOA, DOZ, D BZ, softeners (plasticizers) such as epoxidized soybean oil, linseed oil, petroleum process oil, lubricants such as graphin, stearic acid, other stabilizers, anti-aging agents, vulcanization vulcanization accelerators, vulcanization accelerators, etc.

These fillers may be used alone or in combination of two or more, if necessary. The amount of filler used varies greatly depending on the purpose, but it is usually 5 to 5 parts by weight per 100 parts by weight of rubber.
The amount is approximately 150 parts by weight.

The filler can be added to an area where the rubber in the extruder is in a substantially melted state and exhibits fluidity and can be dispersed with low shear. Disperse in rubber solution.

(2) Add it near the rubber solution supply port of the extruder (for example, on the rubber flow direction side of the rubber supply port).

The following methods are effective.

In addition, among the filled materials, if the particles are strongly cohesive and have enlarged particles, or if they are hard and difficult to make into fine particles, they can be dispersed more uniformly if they are first made into fine particles by mechanical means or the like before use. When adding by method (2) above, if it is liquid, it can be handled quantitatively, but in many cases, it is not possible to add quantitatively if it is solid or powdery. These powders can usually be easily treated quantitatively by making them into a dispersion (slurry) with a solvent or the like.

In particular, when using highly reinforcing carbon black (for example carbon blacks such as N-110, N-220, and N-330) as a filler, the agglomerated carbon particles are mechanically made into fine particles, and organic solvent or By using it in the form of a so-called slurry dispersed in a softener, etc., a high-quality rubber masterbatch with excellent dispersibility and high physical properties can be obtained.

The extruder with a devolatilization function used in the present invention is a screw extruder (extruder) equipped with a vent mechanism to discharge vapors such as solvents generated by volatilization inside the extruder to the outside of the system.
It has functions such as supplying raw April thorns, stirring, mixing, crossing, dispersing, discharging generated steam, and extruding dried products.

If necessary, an opening is provided in the barrel of the extruder, which is the base extruder, and an auxiliary pump is used to take in and out the material, or a part of the screw is replaced with a screw with a different feeding effect, or a screw with a different shape. Different screws are equipped with functions such as mixing, kneading, surface renewal, and vacuum pressure sealing.

In addition, in order to obtain a high quality rubber masterbatch, it is desirable to keep the flow rate of the dried material as low as possible and to maintain a high vacuum in the system as much as possible. If the extruder is multi-screw or rotates at high speed, this can be preferably achieved by connecting a single-screw extruder with a short L/D to the tip of the extruder and operating at low temperature and low speed. The shape of the rubber masterbatch extruded from an extruder is usually obtained in the form of lobes or sheets, and is cut into chips or plates with a diameter of several centimeters. A rubber masterbatch in the form of 10 points can be easily obtained. If necessary, the surface of the Komu Master Patch in the shape of "Beretsu" can be treated with a powder such as talc or an anti-blocking agent made of a surfactant, etc., to make it a fluid material, which can streamline processing and save energy. I can contribute. It is also possible to further refine the particles using a pulverizer or the like to obtain a so-called powdered comb masterbatch of approximately 01 to 3 sized particles.

(Function) The method for producing a rubber masterbatch according to the present invention mixes and disperses the filler into the dissolved rubber in an extremely short time and with low shear compared to the conventional tri-blend method. Uniform dispersion is possible with almost no deterioration in physical properties due to alteration of properties. Furthermore, since an extruder is used, the mixing effect is applied until the end of drying, and there is no fear that the fillers will re-agglomerate and cause poor dispersion. In addition, ordinary rubber has poor thermal conductivity, and if rubber is dried alone, localized high temperature areas may be created, which may cause the rubber to deteriorate (in extreme cases, cause decomposition), but the method of the present invention When inorganic materials are used as fillers, the fillers often have higher thermal conductivity than rubber, and rubber containing these fillers can prevent the formation of localized high-temperature areas and have good drying properties. , which is also advantageous in terms of quality.

(Example) The apparatus shown schematically in FIG. 1 was used to manufacture the rubber master patch used in the following examples.

The extruder numbered 1 in the figure is an L/D key 41, which has a self-cleaning property and is a 3-vent type extruder that rotates in the interlocking direction of two screws.

In the figure, 11, 12, and 13 are vents connected to the vacuum system, and the areas 14, 15, and 16 in the figure are independent in terms of vacuum pressure.

A raw material supply system and an additive supply system indicated by 5, 7 and 6, 8 in the figure are connected to an area near the power source indicated by 14 in the figure.

At the tip of the twin-screw extruder is a single-screw extruder (L/D
''-5) is connected, and the vacuum pressure is the same as the area 16 in the figure.

Parts in the following Examples and Comparative Examples are expressed on a weight basis.

Example-1 (1) A reaction vessel made of glass lining has a density of 0.
960 f/cc, melt index 63 parts by weight of polyethylene 10'O were dissolved in 900 parts by weight of carbon tetrachloride at 100°C under pressure. Using isobutyronitrile as a catalyst, 21 parts by weight of sulfuryl chloride was continuously added over 4 hours to react with polyethylene, and then nitrogen gas was introduced to degas the rubber (chlorosulfonated polyethylene). ) A solution with a content of 14.8 was obtained. The contents of chlorine and sulfur in this rubber were 35.81% and 1.09%, respectively.

(2) To 100 parts by weight of rubber in this rubber solution, 35 parts by weight of titanium oxide, 50 parts by weight of calcium carbonate, 10 parts by weight of plasticizer DOP, 4 parts by weight of magnesium oxide, and 3 parts by weight of dentaerythritol were added. Concentrate to about 1/2 of the solvent
amount was removed.

(3) This viscous solution is quantitatively supplied to the extruder from the raw material supply system 5 in the figure, and the barrel temperature in each region of 14.15°16 in the figure is set to 130°C, 120°C, and 110°C, respectively.
, the vacuum pressure of each vent 11.12 and 13 in the figure is 200 Torr, 1 O ~ 30 Torr,
The barrel of the extruder 2 in the figure was operated at 40 to 60°C to obtain a rubber masterbatch.

(4) 10 parts by weight of stearic acid and 2.0 parts by weight of vulcanization accelerator TRA were added to 100 parts by weight of the rubber in the comb master patch with an open roll to obtain a final blend.

(5) This formulation was heated in Gya-ozone at 40°C for 7 days and the Mooney viscosity (MLH4a t 100°C
) was measured.

As a result, the Mooney viscosity increased by 3 points.

When the same operation was performed and measured for Comparative Example 1 described later, the Mooney viscosity increased by 9 points.

Further, this compound was press-vulcanized at 160° C. for 15 minutes and 43 samples were measured. The results and the results of Comparative Example-1 described below, which were measured using the same procedure, and the tensile strength (Kf/cm)
220 204 Elongation (%)
530. 490 tear strength JIS-B (
K9/'cm) 53 48 Example-
2 In accordance with Example-1 (1), the chlorine and sulfur contents of 8 people with a rubber content of 138 were 35.1% each.
A 1.12% solution of chlorosulfonated polyethylene in carbon tetrachloride was obtained. After concentrating this rubber solution to a rubber content of 575 parts, it was supplied from the supply system 5 in the figure. On the other hand, 6.8 in the figure
．． The additive tank 1, additive feeder, and extruder are arranged so that the connection with the extruder is the shortest, and the ultra-high speed homogenizer M is installed at 18 in the figure.
EGTRON (Switzerland KINEMATICA Gmb)
100 parts by weight of carbon black N-330 Aromatic process oil 20 parts by weight of carbon tetrachloride
The composition of the resulting rubber master patch is as follows: Rubber: 100 parts by weight Carbon black: 40 parts by weight Process oil
A rubber masterbatch was obtained in accordance with Example-1 by supplying 20 parts by weight.

Stearic acid 1 part by weight Magnesium oxide 4 parts by weight per 100 parts by weight of rubber in this rubber masterbatch
3 parts by weight vulcanization accelerator TRA 2
After blending on a roll so that the parts by weight become the final mixture,
Press vulcanization was performed at 160°C for 15 minutes and physical properties etc. were measured.

The results and the results of Comparative Example 2, which were measured in the same manner, are shown below.

(1) Make a cut in the dispersible vulcanized sheet, tear it, observe the torn flat surface with a magnifying glass, and observe ASTM D-2663-69.
Evaluation was made using method B for evaluating the dispersibility of carbon black.

As a result, the dispersion of Examples was 99 coefficients or higher, and no poor dispersion was observed, indicating particularly excellent dispersibility.

On the other hand, the one based on the comparative example had a dispersibility of about 80%.

(2) Physical properties tensile strength K9/c4) 330
285 Growth (person in charge) 290
270 tear strength JIS-B (Kp/m) 7
2 59 Comparative Example-1 (2) of Example-1 using the rubber solution of Example-1 as a raw material
Chip-shaped solids were obtained using an extruder in the same manner as in Example-1 except that the fillers in Section 2 were removed.

The rubber and the filler were kneaded using an internal mixer (Panbury Migizer) to obtain a rubber masterbatch having the same composition as in Example-1.

Comparative Example 2 A solid rubber was obtained by removing the solvent from the 138% comb solution of Example 2 using a steam heating type drum dryer. A comb masterbatch having the same composition as in Example 2 was obtained using an internal mixer according to Comparative Example 1.

Example 3 Butadiene 1-3 and styrene were copolymerized in n-hexane in the presence of 1-4 nohydronaphthalene using an alphine catalyst containing metal sodium dispersion, and the polymerization ratio of butadiene and styrene was 847. A normal hexane solution of rubber (rubber; 127 yen) was obtained.

A rubber masterbatch containing 37.5 parts by weight of aromatic process oil and 45 parts by weight of carbon black l5AF was obtained using an extruder according to Example 2, based on 100 parts by weight of rubber in this rubber solution. .

(However, Pro-7 oil was added to the raw rubber solution, and carbon black was slurried with n-hexane.) Based on this rubber masterbatch, the following final compound was prepared.

Rubber 100 parts by weight Aromatic process oil 375 parts by weight Carn Black N-
22045 parts by weight Stearic acid 3 parts by weight Zinc oxide 5 parts by weight Sulfur
2 parts by weight vulcanization accelerator CZ
1.5 parts by weight of this final blend was press-vulcanized at 150° C. for 30 minutes, and the physical properties of the rubber and the dispersibility of the filler were measured.

Results 1) Physical property tensile strength 284 odor/Cd elongation
575 Tear strength J l5-A 48 Kq/c
m2) Dispersibility When the dispersibility was observed according to Example 2, it was found to be excellent with a dispersibility of 99 inches or more.

Comparative Example-3 Using solid SBR (TSRI 500, manufactured by Japan Synthetic Rubber Co., Ltd.), a rubber masterbatch having the same formulation as in Example-3 was kneaded with an internal mixer, and the operation according to Example-3 was carried out. When the dispersibility of the vulcanized rubber was observed, the dispersibility was about 80%.

(Effects of the Invention) According to the method of the present invention, a high-quality rubber masterbatch can be easily obtained at low cost.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of an extruder suitable for carrying out the present invention. 1...2-screw rotary extruder, 2...single-screw extruder,
3. Power source for twin-screw extruder, 4. Power source for single-screw extruder, 5. Raw material tank, 6. Additive tank, 7. Raw material feeder, 8. Additive. Supply machine, 9.10・Vacuum source (including solvent recovery system), ii, 12.13... Ben 1-114...
Heating, mixing area 1.15...Vent area 1.16...
Vent area 2.17...Dry product extrusion port, 18...Homogenizer. Patent Applicant: Denki Kagaku Kogyo Co., Ltd. - Nyen - + TU Nritoyama Procedural Amendment January 18, 1985 Manabu Shiga, Commissioner of the Japan Patent Office 1 Display of the case 1982 Patent Application No. 240539 2 Name of the invention Rubber Master Relationship with the Case of Person Who Amends Batch Manufacturing Method 3 Patent Applicant Address 1-4-1 Yurakucho, Chiyoda-ku, Tokyo Name (329)'! Contents of amendment to Column 5 of Detailed Description of the Invention in the Specification of Kiikagaku Kogyo Co., Ltd. (1) rBREPDMJ in the 4th line of page 4 of the specification is changed to r
Corrected as BR, EPDMJ. (2) “Ntoluene” on page 4, line 10 of the specification is replaced with “
I am corrected, ``N,) Luen''. (3) "Hexane octane" on page 4, line 11 of the specification is corrected to "hexane, octane." (4) "Preferable" on page 4, line 18 of the specification is corrected to "preferably." (5) "This invention" in line 7 of section 5m of the specification is corrected to "this specification." (6) Corrected “used” on page 9, line 19 of the specification to “used” (1-ro). (7) rAsTMD-26 on page 15, lines 4-5 of the specification
63-69B method” rASTM D-263-69B
``Law'' is corrected. (8) “Butadiene j-
3" is corrected to "butanoene 1,3." (9) "1-4 dihydronaphthalene" on page 16, line 14 of the specification is corrected to "11,4-nohydronaphthalene."

Claims (1)

[Claims] A method for producing a rubber masterbatch, which comprises using an extruder having a devolatilizing function to mix a rubber solution and a filler, and performing kneading and solvent removal in the same device.