JP2976498B2 - Chlorinated polyethylene and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel chlorinated polyethylene.

More specifically, a new chlorine which is excellent in scorch stability during vulcanization operation and compression set of vulcanized product, and which maintains general rubber properties (such as tensile strength and tear strength) of conventional chlorosulfonated polyethylene. The present invention relates to modified polyethylene.

[Prior art] Chlorosulfonated polyethylene is known as an elastomer excellent in weather resistance, ozone resistance, oil resistance, heat resistance, coloring property, etc., and is used for various hose materials for automobiles, wire coating, drawing cloth, It is used for sheets, paints, coatings, roofing materials and the like.

Known vulcanization systems used for chlorosulfonated polyethylene include, for example, metal oxide / sulfur accelerator systems, peroxide systems, and maleimide systems. Among them, the vulcanization system of metal oxide / sulfur accelerator is mainly used because of the balance of rubber properties such as tensile strength and tear strength, storage stability of rubber compound, and danger of handling peroxide. .

However, it is generally known that the vulcanization system of this metal oxide / sulfur accelerator has inferior compression set compared to peroxide systems and maleimide systems. The following is considered as the cause.

The sulfonyl chloride group (—SO ₂ Cl), which is a cross-linking site of chlorosulfonated polyethylene, is a very reactive group. Therefore, in the vulcanization system of the metal oxide / sulfur accelerator, the sulfonyl chloride group (—SO ₂ Cl) is hydrolyzed by moisture in the processing step or moisture contained in the compounding agent (filler, etc.), and a part of the sulfonyl chloride group is hydrolyzed. Turns into acid.
Further, the sulfonic acid forms an ion crosslinked product with the metal ion of the metal oxide. Therefore, metal oxide /
The sulfur accelerator vulcanization system is the original sulfur crosslinked product (covalent bond)
In addition, there are ionic crosslinked products. Therefore, the scorch stability and compression set were considered to be inferior to those of general vulcanization systems.

On the other hand, a sulfonyl chloride group (—SO ₂ Cl)
Attempts have been made to modify water into a functional group that is stable against moisture. For example, a method of reacting a sulfonyl chloride group with ammonia to convert it to a sulfonamide group (DAOlsen,
J. Polymer Sci. AI, 7 , 1913, 1921, 1927 (1969)). However, since this reaction was carried out using a film-like polymer, only the surface was modified. A reaction has also been reported in which chlorosulfonated polyethylene is reacted with an amine in a solvent to convert it to a sulfonamide group (JP-B-34-9285). However, the present inventors examined chlorosulfonated polyethylene obtained by the method of this report, and found that this chlorosulfonated polyethylene had slightly improved compression set, but had very poor scorch stability, and was therefore kneaded. Gelation (crosslinking reaction) progressed during the operation, and it could not be carried out industrially.

[Problems to be Solved by the Invention] That is, an object of the present invention is to provide a novel chlorinated polyethylene which is a modified chlorosulfonated polyethylene in which a vulcanized product exhibits excellent compression set while having excellent scorch stability. It is to provide.

Means for Solving the Problems The present inventors have conducted intensive studies on the development of such a novel chlorinated polyethylene, and as a result, based on the chlorinated polyethylene, 10 to 60% by weight of chlorine and sulfonamide groups. As
It contains 0.2 to 3.0% by weight of sulfur and 0.1 to 1.5% by weight of nitrogen atom, and the sulfonic acid ion content is 0 to 100 [mg NaO ₃ SO (CH ₂ ) ₁₁ CH, measured by methylene blue absorption spectrophotometry.
₃ / g] has been found to be a polymer that achieves the above object, and has led to the present invention.

[Action] The novel chlorinated polyethylene of the present invention is obtained by reacting a chlorosulfonated polyethylene with a primary aliphatic amine represented by the following formula [II] in a solution at a reaction temperature of -30 ° C to 10 ° C. Can be

The chlorosulfonated polyethylene used in the present invention includes linear high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE, VLDPE), and branched low-density polyethylene (LDP).
E), density 0.83-0.97g / cc, weight average molecular weight 20,000-100
10,000 ethylene homopolymers or monomers copolymerizable with ethylene and ethylene (for example, propylene, 1-butene,
Α-olefin having 3 to 8 carbon atoms, such as 4-methylpentene-1; a polymer obtained by chlorination and chlorosulfonation of a copolymer with 1 to 50% by weight of ethylene. .

Methods for chlorinating and chlorosulfonating polyethylene include, for example, dissolving polyethylene in a solvent, using chlorine and sulfurous acid gas or sulfuryl chloride, or sulfuryl chloride alone as a radical generator as a catalyst, and using a cocatalyst as necessary. From the production method.

At this time, the solvent is inert to the halogenation reaction,
Carbon tetrachloride, chloroform, ethane tetrachloride, monochlorobenzene, benzene and the like are used.

As the radical generator, azo radical initiators such as α, α′-azobisisobutyronitrile and azobiscyclohexanecarbonitrile, peroxides such as benzoyl peroxide and acetyl peroxide or ultraviolet rays are used. .

Examples of the promoter include amine compounds such as pyridine and quinoline.

The solution after the completion of the reaction removes acid components such as hydrogen chloride gas and sulfurous acid gas remaining in the solution.

Means for separating and drying the chlorosulfonated polyethylene from the obtained solution include a steam distillation method (for example, US Pat. No. 2,592,814) and a drum drying method (for example, US Pat. No. 2,923,976).
9) and a known method such as an extrusion drying method (for example, JP-A-57-47303).

Typically, the chlorosulfonated polyethylene contains about 10-60% by weight chlorine and about 0.2-3.0% by weight sulfur.

In the present invention, the reaction between the chlorosulfonated polyethylene and the primary aliphatic amine may be carried out by dissolving the chlorosulfonated polyethylene in a solvent. It can also be used for reaction with an aliphatic amine. In both methods, the synthesized chlorosulfonated polyethylene must be separated from the solution and then dissolved again in the solvent. Therefore, it can be said that the latter method is more preferable than the former method in terms of economy and risk of contamination of impurities such as moisture.

The reaction between the chlorosulfonated polyethylene and the primary aliphatic amine according to the present invention must be carried out in a homogeneous system dissolved in a solution. The solvent that can be used may be any solvent that can uniformly dissolve both the chlorosulfonated polyethylene and the primary aliphatic amine. For example, carbon tetrachloride, chloroform, dichloroethane, trichloroethane, tetrachloroethane, monochlorobenzene, dichlorobenzene, halogenated hydrocarbons such as fluorobenzene and benzene, toluene, o-xylene, m-xylene,
There are aromatic hydrocarbons such as p-xylene. These solvents must be used after being dehydrated by molecular sieve or distillation. If the solvent contains a large amount of water, a side reaction occurs in which a sulfonic acid is formed from the sulfonyl chloride group (—SO ₂ Cl) and the water, and the novel chlorinated polyethylene of the present invention cannot be obtained.

The amount of soluble chlorosulfonated polyethylene is 0.2
~ 30% by weight is preferred. If it exceeds 30% by weight, it is difficult to carry out a uniform reaction due to poor stirring efficiency due to high viscosity. If the amount is less than 0.2% by weight, a large amount of a solvent is required, and the productivity is remarkably deteriorated due to problems such as removal from the reactants.

The primary aliphatic amine used in the present invention is an amine having an alkyl group having 1 to 20 carbon atoms represented by the following formula [II].

For example, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, sec
-Butylamine, tert-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-
Octylamine and n-nonylamine.

The amount of the primary aliphatic amine used in the reaction between the chlorosulfonated polyethylene and the primary aliphatic amine in the present invention is based on the mole of the sulfonyl chloride group (—SO ₂ Cl) of the chlorosulfonated polyethylene. The molar ratio is preferably 2 to 50 times, and particularly preferably 5 to 40 times.

The reaction between the chlorosulfonated polyethylene and the amine is
The reaction proceeds in a reaction route represented by the following formula [III].

Therefore, when the amount of the amine used is less than 2 mol times, the amine reforming reaction does not completely proceed, and unreacted sulfonyl chloride groups remain. When the amount of the amine used exceeds 50 mole times, the amine reforming reaction proceeds completely, but an excess of unreacted amine remains and cannot be said to be an economical reaction.

It is essential that the reaction between the chlorosulfonated polyethylene of the present invention and the primary aliphatic amine be performed at a low temperature of -30 to 10 ° C. An earlier report (JP-B-34-9285) shows that the reaction of chlorosulfonated polyethylene with an amine is carried out at room temperature or higher. However, as a result of our investigation, when the reaction was performed at a reaction temperature exceeding 10 ° C., the obtained chlorosulfonated polyethylene contained a large amount of sulfonic acid,
Mooney viscosity was high, and some gelled. Therefore, the scorch stability and the compression set of the vulcanized product were hardly improved. On the other hand, when the reaction is carried out at a temperature lower than -30 ° C, the reaction rate is slow and a long reaction time is required, which is not economical. Preferably, it is −30 to 5 ° C.

The chlorine content of the novel chlorinated polyethylene of the present invention is 10 to 60% by weight, preferably 20 to 45% by weight, based on the novel chlorinated polyethylene. The sulfur content is 0.2-3.0% by weight, and the nitrogen content is 0.1-1.5% by weight. The sulfur content and the nitrogen content are measures of the amount of sulfonamide groups (—SO ₂ NHR) contained in the novel chlorinated polymer, and are factors that govern the vulcanization behavior such as the vulcanization rate and vulcanization density. Preferably, the sulfur content is 0.5-1.8% by weight and the nitrogen content is 0.
2 to 1.3% by weight.

The structural unit of the novel chlorinated polyethylene of the present invention is represented by the formula [I] (A, B, C and D represent mol%). This mol% corresponds to the above-mentioned sulfur content, nitrogen content and chlorine content.

The weight average molecular weight (Mw) of the novel chlorinated polyethylene of the present invention is 20,000 or more. Preferably, 20,000 to 1,
000,000. When the weight average molecular weight (Mw) is less than 20,000, sticking to the roll or the Banbury mixer occurs when kneading with a roll or a Banbury mixer. Further, when used as an unvulcanized product or a vulcanized product, its tensile properties and the like are extremely poor.

The sulfonic acid ion content contained in the novel chlorinated polyethylene of the present invention is from 0 to 100 [mg NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ / g] as measured by methylene blue absorption spectrophotometry. Preferably, it is 0 to 50 [mg NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ / g]. This sulfonate ion is a by-product [formula IV] formed by hydrolysis of the sulfonyl chloride group (—SO ₂ Cl) in the chlorosulfonated polyethylene using the amine as a catalyst.

Sulfonate ion content is 100 [mg NaO ₃ SO (CH ₂ ) ₁₁
When CH ₃ / g] is exceeded, the scorch stability and the compression set of the vulcanizate are not improved. The causes are as follows.

The sulfonate ion easily forms an ion crosslinked product with the metal ion of the metal oxide used in the vulcanization system of the commonly used metal oxide / sulfur accelerator. This significantly reduces the scorch stability of the formulation. In addition, since an ionic crosslinked product exists in addition to the original sulfur crosslinked product, the compression set of the vulcanized product is inferior.

The novel chlorinated polyethylene of the present invention is obtained by adding a compound such as a vulcanizing agent, a vulcanization accelerator, a reinforcing agent, a filler, a plasticizer, a softening agent, an antioxidant, etc. It is used as a vulcanizate. As the vulcanizing agent, sulfur and organic peroxide are used. Examples of the vulcanization accelerator include sulfur-based vulcanizations such as tetramethyltyrium disulfide (TT), dibenzothiazyl disulfide '(DM), dipentamethylenethiuram tetrasulfide (TRA), and 2-mercaptoimidazoline (# 22). Accelerators, peroxides such as dicumyl peroxide (DCP), and maleimides such as N, N'-m-phenylenedimaleimide (PM) are used. Zinc oxide (ZnO) is used as a vulcanization accelerator. Examples of the filler include charcoal, clay, silica, an oil softener, and carbon black. These compounding agents are mixed and kneaded with a novel chlorinated polyethylene in a roll or a Banbury mixer, and then subjected to press vulcanization, steam vulcanization, UHF vulcanization, and the like.

[Examples] Next, the present invention will be described in more detail based on examples, but these are examples for helping to understand the present invention, and the present invention is not limited by these examples.

The values used in these examples were obtained in accordance with the following measurement methods.

Chlorine and sulfur content: Combustion flask method Nitrogen content: JIS K 6384 Mooney viscosity: JIS K 6300 (ML _{1 + 4} 100 ° C) Vulcanized rubber properties: JIS K 6301 Sulfonate ion content: Methylene blue absorption spectrophotometry (anionic surfactant Hereinafter, the methylene blue absorptiometry will be described in more detail.

A solution prepared by dissolving 1.36 g of methylene blue (3,7-bis (amino) phenothiazine-5-ium chloride) in 1 L of 0.01 N hydrochloric acid is prepared. Take 10 ml of a 0.5% by weight chloroform solution of a sample for measuring the sulfonic acid ion content, add the same amount of the above adjusted methylene blue reagent, and shake well. After intermittent shaking for 3-4 hours, the two layers are separated,
Optical density of chloroform layer (Measuring device: UV-VI manufactured by Shimadzu)
SIBLE RECORDING SPECTROPHOTOMETER UV-265FW, measurement wavelength: 650 nm). A blank experiment without a sample for measurement was performed at the same time and corrected. The concentration of the sulfonate ion was determined using an absorbance-concentration calibration curve prepared using sodium dodecyl sulfate [NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ ] in advance.

Structural unit: The structure was identified and quantified by ¹³ C-NMR.

・ Equipment JEOL FX-100 ・ Conditions Solvent C ₆ D ₆ Temperature Room temperature Pulse Pulse width 7μsec Pulse interval 5sec Total number of times 30,000 or more GPC: Measurement of molecular weight and molecular weight distribution ・ Model: HLC802A manufactured by Tosoh Corporation ・ 1 column 67000H manufactured by Tosoh Corporation ・ Two GMH6 ・ Tetrahydrofuran solvent ・ Flow rate 1.2ml / min ・ Pressure 45kg / cm ²・ Temperature 38 ° C・ Sample concentration 0.10wt% ・ Calibration curve Standard polystyrene manufactured by Tosoh Corporation IR measurement: manufactured by JASCO Corporation Model JASCO IR-810 Example-1 700 g high-density polyethylene (melt index) in a 10 L autoclave with a stirrer 5.3g / min, density 0.963g / c
c) is dissolved in 7,000 g of molecular sieve dried carbon tetrachloride at 110 ° C. under a pressure of 3.0 kg / cm ² . Α, α'-azobisisobutyronitrile 0.945 as a radical generator
g, sulfuryl chloride with 0.28 g of pyridine as cocatalyst
The reaction is carried out at 100 ° C. for 3 hours under a pressure of 1,485 g and 3.0 kg / cm ² .

After the reaction, the acid content remaining in the solution was removed by blowing nitrogen. The carbon tetrachloride solution concentration of this chlorosulfonated polyethylene was 13% by weight. Carbon tetrachloride dried with molecular sieve was added to this solution to adjust the concentration to 8% by weight, and used for the next amination reaction.

A portion of this solution was fed to a dryer to separate the product from the solvent. Analysis showed that the chlorosulfonated polyethylene contained 35.8% by weight of chlorine and 0.96% by weight of sulfur.

The amination reaction was performed while the reaction solution was kept at 0 ° C. under a nitrogen atmosphere. 387 g of n-propylamine are added and 5
The reaction was carried out by stirring for hours. The reaction solution was fed to a drum dryer to separate the reactants from the solvent.

As a result of the analysis, the obtained polymer was 34.4% by weight of chlorine,
It contained 0.96% by weight sulfur and 0.42% by weight nitrogen.

The sulfonic acid ion content was 8 [mg NaO ₃ SO (C
H ₂ ) ₁₁ CH ₃ / g].

 The Mooney viscosity was 89.

FIG. 1 shows the ¹³ C-NMR spectrum of this polymer.
FIG. 2 shows the IR spectrum. From the IR spectrum, the sulfonyl chloride group of the chlorosulfonated polyethylene (attributed to 1,370 and 1,160 cm ^-1 ) has completely disappeared and changed to a sulfonamide group (attributable to 1,320 and 1,140 cm ^-1 ). You can see that.

 Table 1 shows the mol% of the structural units.

Table 1 shows the molecular weight and molecular weight distribution of this polymer.

Using an 8-inch roll heated to 40 ° C., the mixture was roll-kneaded according to the formulation shown in Table 2. Press vulcanization was performed at 160 ° C. for 30 minutes to obtain a vulcanized rubber sheet.

 The results of evaluation of the physical properties of the vulcanized rubber are shown in Table 3.

Examples 2 to 3 An amination reaction was performed using the chlorosulfonated polyethylene solution obtained in the same manner as in Example 1. Example-2 used 245 g of n-butylamine and Example-3 used 39
5 g of n-pentylamine was added and reacted as in Example-1. The results of evaluation of the physical properties of the vulcanized rubber are shown in Table 3.

Example-4 In a 10-liter autoclave equipped with a stirrer, 1,000 g of chlorosulfonated polyethylene (TS-530, manufactured by Tosoh Corporation, chlorine content: 35.5% by weight, sulfur content: 1.01% by weight) was dewatered with molecular sieve to 7000 g. Dissolved in chloroform.
After dissolution, the inside of the reactor was kept at -5 ° C under a nitrogen atmosphere.
100 g of n-propylamine was added, and the reaction was carried out with stirring for 5 hours. The reaction solution was fed to a drum dryer to separate the reactants from the solvent. As a result of the analysis, the obtained polymer was 34.4% by weight of chlorine, 1.00% by weight of sulfur, 0.42% by weight.
Contained nitrogen.

The sulfonic acid ion content was 5 mg NaO ₃ SO (C
H ₂ ) ₁₁ CH ₃ / g].

Roll kneading was performed in the same manner as in Example 1 to obtain a vulcanized rubber sheet. Table 3 shows the physical property evaluation results.

Comparative Example-1 In a 10 L autoclave equipped with a stirrer, 400 g of chlorosulfonated polyethylene (TS-530, manufactured by Tosoh Corporation, chlorine content: 35.5 wt%, sulfur content: 1.01 wt%) was added to 4,000 ml of sufficiently dehydrated toluene. Dissolved. The solution is then
C.

192 g of N-ethyl allylamine were added and the reaction mixture was kept stirring at 60 ° C. overnight. It is poured into 4000 ml of methanol and the product is separated. The viscous polymer was transferred to the reactor and stirred with 2,000 ml of methanol by chopping into small pieces with high speed sharp blades. further,
The polymer was separated, filtered and repeated twice with methanol. Suction drying followed by air drying overnight. The resulting polymer is
It contained 34.3% by weight of chlorine, 1.00% by weight of sulfur and 0.4% by weight of nitrogen. The sulfonic acid ion content is 130 [m
g NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ / g].

 The Mooney viscosity was 160.

Table 1 shows the structural unit content and molecular weight of this polymer.

Using an 8-inch roll heated to 40 ° C., the mixture was roll-kneaded according to the formulation shown in Table 2. Press vulcanization was performed at 160 ° C. for 30 minutes to obtain a vulcanized rubber sheet.

 Table 4 shows the evaluation results of the physical properties of the vulcanized rubber.

Comparative Example 2 An amination reaction was performed using the chlorosulfonated polyethylene solution obtained in the same manner as in Example 1. The amination reaction was performed while maintaining the reaction solution in a nitrogen atmosphere at 40 ° C. 387 g of n-propylamine was added, and the mixture was stirred for 5 hours to carry out a reaction. As a result of the analysis, the obtained polymer was 3
It contained 4.8% by weight of chlorine, 0.96% by weight of sulfur and 0.41% by weight of nitrogen. The sulfonic acid ion content is 130 [m
g NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ / g]. The Mooney viscosity was 154.

 Table 4 shows the evaluation results of the physical properties of the vulcanized rubber.

Comparative Example-3 An amination reaction was performed using the chlorosulfonated polyethylene solution obtained in the same manner as in Example-1. The amination reaction was performed while maintaining the reaction solution at 60 ° C. under a nitrogen atmosphere. 387 g of n-propylamine was added, and the mixture was stirred for 5 hours to carry out a reaction. As a result of the analysis, the obtained polymer was
It contained 34.5% by weight of chlorine, 0.86% by weight of sulfur and 0.40% by weight of nitrogen. The sulfonic acid ion content is 152 [m
g NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ / g]. The Mooney viscosity was 174.

 Table 4 shows the evaluation results of the physical properties of the vulcanized rubber.

Comparative Example-4 An amination reaction was performed using a chlorosulfonated polyethylene solution obtained in the same manner as in Example-1. The amination reaction was performed while the reaction solution was kept at 0 ° C. under a nitrogen atmosphere. 23 g of n-propylamine was added and the reaction was carried out by stirring for 5 hours. As a result of the analysis, the obtained polymer was
It contained 35.4% by weight of chlorine, 0.96% by weight of sulfur and 0.08% by weight of nitrogen. Sulfonate content is 10 [mg
NaO ₃ SO (CH ₂ ) ₁₁ CH ₃ / g].

The spectrum of the obtained polymer is shown in FIG. 3, but no absorption attributed to the sulfonamide group was observed, and unreacted sulfonyl chloride groups (1,370 and 1,160 cm ^-1 ) were observed.

 The Mooney viscosity was 59.

 Table 4 shows the evaluation results of the physical properties of the vulcanized rubber.

Table 2 Formulation weight% Chlorosulfonated polyethylene 100 MgO # 150 10 Dipentamethylenethiuram.2 Tetrasulfide pentaerythritol 3 [Effects of the Invention] The novel chlorinated polyethylene obtained by the present invention is excellent in scorch stability at the time of vulcanization operation, compression set of the vulcanized product, and the like, and has the rubber properties (tension) of the conventional chlorosulfonated polyethylene polymer. Strength, tear strength, and Mooney viscosity).

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the novel chlorinated polyethylene obtained in Example 1.
NMR spectrum, spectrum 1 in FIG. 2 is the IR spectrum of the novel chlorinated polyethylene obtained in Example 1, spectrum 2 is the IR spectrum of the chlorosulfonated polyethylene, and FIG. 3 is the chlorinated polyethylene obtained in Comparative Example 4. of
It is an IR spectrum.

Claims (2)

(57) [Claims] 1. The method according to claim 1, which comprises 10 to 60% by weight of chlorine, 0.2 to 3.0% by weight of sulfur as a sulfonamide group, 0.1 to 1.5% by weight of nitrogen atom, and the content of sulfonic acid ion is measured by methylene blue absorption spectrophotometry. And 0-100 [mg NaO ₃ SO (CH ₂ )
₁₁ CH ₃ / g], a chlorinated polyethylene having a weight average molecular weight of 20,000 or more. 2. A chlorosulfonated polyethylene having the following formula: (R: an alkyl group having 1 to 20 carbon atoms) is obtained by reacting a primary aliphatic amine represented by the following formula with a reaction temperature of -30 ° C to 10 ° C in a solution. The method for producing a chlorinated polyethylene according to the above.