JPH0741619A - Production of chlorinated polyethylene crosslinked composition - Google Patents

Abstract

PURPOSE:To produce the subject composition reduced in a foaming phenomenon on a crosslinking treatment, excellent in adhesivity to other rubbers, etc., and useful for fuel hoses, etc., by adding calcined lime, etc., to crosslinking components consisting mainly of a chlorinated PP and a specific chlorinated copolymer. CONSTITUTION:A composition comprising (A) 100 pts.wt. of the mixture of (i) 5-95wt.% of a chlorinated PE and (ii) 95-5wt.% of a chlorinated copolymer having a chlorine content of 2-45wt.% and produced by chlorinating an ethylene- alkyl acrylate ester copolymer having an alkyl acrylate ester content of 1-20wt.%, (B) 0.1-5 pts.wt. of a mercaptotriazine compound, (C) a compound having a boiling point of >= approximately 110 deg.C, such as an amine (organic acid salt) or diarylguanidine in an amount of 0.5-3 moles per mole of the component B, (D) 1-30 pts.wt. of calcined lime, and (E) 0.1-2 pts.wt. of an organotin compound of formula: R2SnY or R3SnZ2 (R is 1-20C alkyl; Y is O, 3-20C aliphatic dicarboxylic acid residue; Z is 1-20C aliphatic carboxylic acid residue) is crosslinked with microwaves to provide the objective crosslinked composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a crosslinked composition mainly composed of chlorinated polyethylene and a chlorinated ethylene-acrylic acid alkyl ester copolymer which have excellent adhesion to other rubbers.

[0002]

2. Description of the Related Art Chlorinated polyethylene is known as a polymer having excellent mechanical properties, heat resistance, oil resistance, chemical resistance, and weather resistance among various polymer materials by being sufficiently crosslinked. Chlorinated polyethylene produced by a method including a chlorination step at a temperature near the melting point of polyethylene is a material that is drawing attention as an elastomer material. In recent years, in the rubber industry, a continuous cross-linking method using microwave cross-linking (hereinafter referred to as UHF cross-linking) has been actively performed. UHF crosslinking is described in, for example, "Crosslinking Equipment Handbook" (published by Taiseisha Co., Ltd., first edition on March 15, 1983), pages 122 to 134. This cross-linking method uses styrene-butadiene rubber (SBR), ethylene-
Propylene rubber (EPDM) and the like are widely used in the rubber industry, but chlorinated polyethylene rubber is not yet used. Further, in the rubber industry in recent years, two kinds of polymers having different characteristics are cross-linked and bonded,
A method for producing a laminated body that takes advantage of each characteristic has been actively performed. In order to improve the above-mentioned adhesiveness, we proposed a composition mainly composed of a mixture of chlorinated polyethylene and a chlorinated ethylene-acrylic acid alkyl ester copolymer (Japanese Patent Application No. 61-19037).

[0003]

The present inventors have actually carried out UHF cross-linking on a composition mainly composed of a mixture of the above-mentioned chlorinated polyethylene and a chlorinated ethylene-alkyl acrylate copolymer. It was found that there is a phenomenon in which the rubber after cross-linking foams, that is, a large number of large and small bubbles are generated in the rubber, which makes it practically unusable. Therefore, the main object of the present invention is to provide a mixture of a chlorinated polyethylene and a chlorinated ethylene-alkyl acrylate copolymer which suppresses the above-mentioned foaming phenomenon and has excellent UHF crosslinkability, without causing deterioration of other physical properties. The present invention provides a crosslinking composition.

[0004]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to solve the above problems, as a result of blending quick lime, or quick lime and an organotin compound in the crosslinking composition, The present invention has been completed by solving the problem of foaming at the time of UHF cross-linking and finding that it gives excellent cross-linking physical properties.

That is, according to the present invention, (a) the chlorine content obtained by chlorinating an ethylene-alkyl ester copolymer having (a) 5 to 95% by weight of chlorinated polyethylene and 1 to 20% by weight of alkyl acrylate is 2 ~ 45% by weight
A chlorinated copolymer of 95 to 5% by weight of a mixture 10
0 parts by weight, (b) 0.1 to 5 parts by weight of mercaptotriazines, (c) an amine having a boiling point of about 110 ° C. or higher, an organic acid salt of the amine, or an adduct thereof, diarylguanidine, aniline and aldehyde. Condensation products of and 1
One or more compounds selected from 2-benzothiazylsulfenamide of primary or secondary amine (b)
0.5 to 3 mol per 1 mol of the component, (d) quicklime 1 to 3
A method for producing a chlorinated polyethylene cross-linked composition, which comprises cross-linking a composition containing 0 part by weight, (e) 0.1 to 2 parts by weight of an organic tin compound described later by microwave.

As the chlorinated polyethylene of the component (a) used in the present invention, chlorinated polyethylene having an arbitrary chlorine content, crystallinity and molecular weight distribution is targeted, and particularly polyethylene having a melt index of 0.01 to 100 is used. Amorphous or substantially amorphous chlorinated chlorine having a chlorine content of 20 to 50% by weight is preferable because the effect of the present invention can be remarkably exhibited.

In the present invention, the chlorinated ethylene-acrylic acid alkyl ester copolymer blended with chlorinated polyethylene (hereinafter sometimes abbreviated as "chlorinated ethylene copolymer") means ethylene and acrylic acid alkyl ester or methacrylic acid. An acid alkyl ester (both of which are hereinafter referred to as (meth) acrylic acid alkyl ester) is polymerized by a known method and is then post-chlorinated. The content of the (meth) acrylic acid alkyl ester in the copolymer is usually 1% by weight or more, and preferably 2 to 20% by weight in the copolymer. When it is less than 1% by weight, it is difficult to obtain good adhesiveness, which is the object of the present invention, as a composition. The molecular weight of the copolymer is not particularly limited,
Considering the easiness of chlorination reaction and the properties of the crosslinked product, particularly the use as an elastomer material, those having a melt index of 0.1 to 100 are suitable. The chlorine content of the chlorinated ethylene copolymer varies depending on the type, molecular weight, composition, etc. of the copolymer, but it is usually 2 to 45% by weight, preferably 10 to 40% by weight. Those having a chlorine content of more than 45% by weight are not preferable because the rubber elasticity disappears and the workability is impaired and the chlorination takes a long time. If the chlorine content is less than 2% by weight, the number of chlorine atoms, which serve as crosslinking points during crosslinking, is small in the molecular chain of the copolymer, and the crosslinking does not occur effectively, which is not preferable.

The (meth) acrylic acid alkyl ester, which is one of the raw materials for the chlorinated ethylene copolymer of the present invention, is represented by the following general formula (I).

[0009]

[Chemical 1] In the above general formula (I), R ¹ is an alkyl group having 1 to 5 carbon atoms, and R ² is hydrogen or a methyl group.

Specific examples of the compound represented by the general formula (I) include methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, methyl methacrylate, ethyl methacrylate and n-methacrylate. Butyl, t-butyl methacrylate, etc. are mentioned.

As a method for chlorinating a copolymer of ethylene and an alkyl (meth) acrylate, a method according to the method for producing chlorinated polyethylene can be adopted. That is, any of the conventional solution method and aqueous suspension method can be adopted. However, the solution method requires a large amount of cost to recover the solvent, and there is also a problem of the viscosity of the reaction solution in the chlorination reaction step, and therefore the aqueous suspension method is generally preferable. The copolymer is usually obtained in the form of granules or pellets, which are pulverized by a conventional method to be used in the form of powder.

The blending ratio of the chlorinated polyethylene and the chlorinated ethylene copolymer in the present invention is usually in the range of 95 to 5: 5 to 95% by weight. If the amount of chlorinated polyethylene is less than 5% by weight, the excellent performance possessed by itself cannot be utilized, and if the amount of chlorinated ethylene copolymer is less than 5% by weight, the adhesiveness is sufficient. No results are obtained. The component (b) mercaptotriazines used in the present invention is represented by the following general formula (II).

[0013]

[Chemical 2] (However, R ³ is selected from the group consisting of a mercapto group, an alkoxy group, an alkylamino group, a dialkylamino group, a cycloalkylamino group, a dicycloalkylamino group, and an arylamino group.)

Specific examples of the above general formula (II) include 1,
3,5-trithiocyanuric acid, 1-methoxy-3,5-
Dimercaptotriazine, 1-hexylamino-3,5
-Dimercaptotriazine, 1-diethylamino-3,
5-dimercaptotriazine, 1-dibutylamino-
Examples thereof include 3,5-dimercaptotriazine, 1-cyclohexylamino-3,5-dimercaptotriazine, 1-phenylamino-3,5-dimercaptotriazine and the like.

The basic amine compound as the component (c) used in the present invention, that is, the amine having a boiling point of about 110 ° C. or higher, is preferably an aliphatic or cycloaliphatic first, second or It is a tertiary amine and has a pk value of about 4.
5 or less is preferable. Representative examples of such amines include n-hexylamine, octylamine, dibutylamine, tributylamine, trioctylamine, di (2-ethylhexyl) amine, dicyclohexylamine, hexamethylenediamine.

As the organic acid salt or adduct of amine, amine having a pk value of about 4.5 or less and pk value of about 2.
Salts or adducts with 0 or more organic acids are preferred. Representative examples of such organic acid salts of amines include n-butylamine acetate, dibutylamine oleate, hexamethylenediaminecarbamate, and dicyclohexylamine salt of 2-mercaptobenzothiazole. Examples of diarylguanidine in the basic amine compound include diphenylguanidine and ditolylguanidine. Further, as the condensation product of aniline and aldehyde, aniline and at least one kind of carbon number 1 to 7
The condensation products with aldehydes of are preferred. Specific examples include a condensate of aniline and butyraldehyde, a condensate of aniline and heptaaldehyde, a condensate of aniline and acetaldehyde, and butyraldehyde. Again 1
The secondary or secondary amine 2-benzothiazylsulfenamide is represented by the following general formula (III).

[0017]

[Chemical 3] (However, R ⁴ and R ⁵ may be the same or different and each is a group having 1 to 12 carbon atoms selected from hydrogen, an alkyl group, a cycloalkyl group and an aralkyl group and having no substituent containing a hetero atom. Yes, and R ⁴ and R ⁵ are not both hydrogen)

The primary or secondary amine forming the sulfenamide preferably has a pk value of about 4.5 or less, and specific examples include cyclohexylamine, butylamines, diethylamines, dipropylamines,
Examples include dibutylamines, dihexylamines, dioctylamines, dilaurylamines, dicyclohexylamine, piperidine, pipericone, morpholine and piperazine.

The (d) component quicklime used in the present invention is represented by the chemical formula CaO, and is preferably finely pulverized in terms of dispersion of quicklime in rubber and physical properties of cross-linking. Further, a premixed rubber plasticizer may be used to improve dispersibility. As the quicklime used for such a purpose, a trade name “CML # 21” manufactured by Omi Chemical Co., Ltd. is commercially available. The quick lime not only prevents foaming during UHF crosslinking, but also has an action as an acid acceptor during crosslinking, but it is usually advantageous to use in combination with another metal compound that serves as an acid acceptor.

Such an acid acceptor imparts stability to the crosslinked product and an appropriate crosslinking rate, and specifically, the periodic table
Group II metal oxides (excluding CaO), hydroxides, carboxylates, silicates, carbonates, phosphites, borates, oxides of Group IVA metals of the Periodic Table, basic phosphites Examples thereof include salts, basic carbonates, basic carboxylates, basic sulfites and tribasic sulfates. Specific examples include magnesia, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, slaked lime, calcium carbonate, calcium silicate, calcium stearate, zinc stearate, calcium phthalate, magnesium phosphite, calcium phosphite, zinc. Hana, tin oxide, litharge, red lead, lead white, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic lead phosphite, basic tin phosphite, basic lead sulfite, tribasic Lead sulfate etc. can be mentioned.

The blending amount of each of the above components is 0.1 to 5 parts by weight, preferably 0.1 part by weight, based on 100 parts by weight of the total of (a) chlorinated polyethylene and chlorinated ethylene copolymer. 5 to 3 parts by weight, component (c) is 0.5 to 3 mol per 1 mol of component (b), and component (d) is 1 to 30 parts by weight. If the amount of the component (d) is less than 1 part by weight, foaming cannot be suppressed, and if it is more than 30 parts by weight, the physical properties after crosslinking are deteriorated. The amount of the metal compound serving as an acid acceptor used in combination with the component (d) is appropriately in the range of 0.5 to 20 parts by weight.

The organotin compound (e) used in the present invention is represented by the following general formula (IV). R ₂ SnY or R ₂ SnZ ₂ (IV) (wherein R is a C _{1 to} C ₂₀ alkyl group, Y is oxygen or C ₃
To C ₂₀ aliphatic dicarboxylic acid residue, Z is C _{1 to} C ₂₀ aliphatic carboxylic acid residue) Specifically, di-n-butyltin maleate, di-n-octyltin maleate, succinic acid Examples thereof include di-n-butyltin and di-n-butyltin oxide. Such organotin compounds are known as stabilizers for polyvinyl chloride and the like, but have not yet been studied for crosslinking compositions.
That is, it is extremely useful to add an anti-scorch agent to the cross-linking composition to prevent premature cross-linking. Since it is exposed to extremely high temperatures, known scorch inhibitors such as organic acids such as phthalic anhydride and N- (cyclohexylthio) -phthalimide have poor thermal stability and are not effective as scorch inhibitors. Since the present inventors have conducted various studies since various polyvinyl chloride stabilizers are good in terms of thermal stability, as a result, only the above-mentioned organotin compound has a scorch-preventing effect, and the processing stability of the composition is It has been found that it has an effect of suppressing foaming at the time of UHF cross-linking as well.

The amount of the organotin compound (e) used in the present invention is 0.1 to 2 with respect to 100 parts by weight of chlorinated polyethylene.
If the amount is less than 0.1 part by weight, the scorch preventing effect, the thermal stability and the foaming preventing effect are not obtained, and if the amount exceeds 2 parts by weight, the crosslinking rate is significantly slowed, which is not preferable.

The compositions used in the present invention include various compounding agents that are commonly used in the art, such as fillers, reinforcing agents, plasticizers, stabilizers, antiaging agents, lubricants, and viscosity agents. Addition of additives, pigments, flame retardants, etc. is free.

As a method for mixing the composition used in the present invention, the polymer components may be mixed in advance and the crosslinking component may be mixed therein. Usual mixers such as Hensiel mixer, open roll, kneader and Banbury mixer can be used. When performing such mixing, each component other than mercaptotriazines and quick lime is mixed in a mixture of chlorinated polyethylene and a chlorinated ethylene-based copolymer at 150 to 220 ° C., and then mercaptotriazines and quick lime are heated to 150 ° C. or lower. , Preferably 120
Mixing at ~ 50 ° C is preferred. When the first-stage mixing is carried out at a temperature lower than 150 ° C., foaming tends to be large, and the cause thereof is not clear, but it is considered that water in the composition is volatilized. Further, if the mixing temperature is higher than 220 ° C., the polymer component may be thermally decomposed.

The composition used in the present invention is particularly a rubber having different properties on both sides by UHF cross-linking adhesion to other rubbers, for example, polymers having other excellent properties such as acrylonitrile-butadiene rubber and epichlorohydrin rubber. It is very suitable for manufacturing and the interface of the laminate is very firmly adhered. The composition of the acrylonitrile-butadiene rubber for producing such a laminate is described on pages 117 to 120 of "Synthetic Rubber Processing Technology Complete Book Nitrile Rubber" (Taisei Co., Ltd., October 30, 1976, first edition). There is. As a method for producing the UHF crosslinked laminate, the crosslinking method described in the above-mentioned "Crosslinking Equipment Handbook", pages 122 to 134 can be used.

[0027]

EXAMPLES Examples, reference examples and comparative examples will be shown below, but all parts and percentages in the examples are based on weight. Examples, Reference Examples, Comparative Examples (Production of Chlorinated Ethylene Copolymer) Chlorinated Ethylene Copolymer A Melt Index 6.5, Ethyl Acrylate Content 1
8% by weight of ethylene-ethyl acrylate copolymer powder 5
70 kg of water, a wetting agent and a dispersant are put into a glass-lined pressure type reactor having a volume of 100 l, and the mixture is stirred for 8 hours.
After raising the temperature to 0 ℃, chlorine gas is introduced and the gauge pressure is 3 kg.
The chlorination reaction was carried out at 80 ° C./cm ² for 5 hours. After the reaction, the chlorinated product was washed with water and dried to obtain 6.9 kg of a chlorinated ethylene-ethyl acrylate copolymer having a chlorine content of 30%. Chlorinated ethylene-based copolymer B Chlorinated ethylene-acrylic acid having a chlorine content of 13% in the same manner as in the process for producing the chlorinated ethylene-based copolymer A except that the reaction time was 2.5 hours. 5.5 kg of an ethyl copolymer was obtained. Chlorinated Ethylene Copolymer C Ethylene-ethyl acrylate copolymer powder having a melt index of 0.7 and an ethyl acrylate content of 3.5 wt% was used, and the reaction time was set to 8 hours under the chlorination reaction conditions. 7.8 kg of a chlorinated ethylene-ethyl acrylate copolymer having a chlorine content of 42% was obtained in the same manner as in the production method of the chlorinated ethylene copolymer A except for the above.

(Production of Crosslinked Composition) Of the compositions shown in Table 1, after polymer components were premixed with a kneader,
Other ingredients are added and mixed, and when the mixing is completed, the composition is heated to 190 ° C
The jacket temperature of the kneader is adjusted so that it becomes, and then a mercaptotriazine (OF-10
0) and quicklime (CML # 21) were kneaded for 10 minutes to form a sheet having a thickness of 2 mm.

The chlorinated polyethylene in the composition is a rubbery polymer having a chlorine content of 40% produced by high-temperature chlorination of high density polyethylene having a melt index of 0.8 in an aqueous suspension. The above sheet was extruded by a vent type extruder with a diameter of 4.5 mm into a tube with an inner diameter of 8 mm and an outer diameter of 14 mm at a speed of 3 m / min, and immediately connected to the vent type extruder. 1
After heating the tube temperature to 190 ° C with the UHF heating experimental device of m.
The mixture was placed in a gear oven at 0 ° C. for 5 minutes to perform crosslinking heating.

The expansion ratio was measured as follows. That is, the above-mentioned sheet and the tube after UHF cross-linking are about 2 cm x 2
The sample was cut into cm squares, the specific gravity was measured, and the expansion ratio was calculated by the following formula. Expansion ratio (%) = (1-specific gravity of UHF after crosslinking / specific gravity of sheet) x 100

For crosslinked products having an expansion ratio of 5% or less, J
A tensile test and hardness measurement were performed according to ISK-6301. Separately, epichlorohydrin rubber and acrylonitrile-butadiene rubber having the following compositions were kneaded in the same manner as above to obtain a rubber sheet having a thickness of 2 mm. Epichlorohydrin rubber sheet part Epichlorohydrin rubber ^{* 1} 100 HAF carbon 40 Magnesium oxide 5 Trithiocyanuric acid 0.8 Diphenylguanidine 0.6 Quicklime 3 Acrylonitrile butadiene rubber sheet part Acrylonitrile butadiene rubber ^{* 2} 100 HAF carbon 40 Zinc white 5 N-cyclohexyl- 2 Benzothiazyl sulfenamide 2 Tetramethyl thiuram disulfide 1.5 Sulfur 0.5 Quick lime ^{* 3} 10 * 1: "Epichromer C" (Daiso product name) * 2: "N230S" (Nippon Synthetic Rubber Co., Ltd.) * 3: CML # 21 (Omi Chemical Co., Ltd.)

Two vent-type extruders were connected by a chlorbed die, and two layers were extruded with the rubber sheet made of the composition as an outer layer and the epichlorohydrin rubber sheet or the acrylonitrile-butadiene rubber sheet as an inner layer. 8mm, outer diameter 18mm (thickness of inner layer rubber material 3
mm, and the outer layer rubber material has a thickness of 2 mm), and UHF crosslinking was performed in the same manner as above except that a two-layer rubber tube was used. The interlayer adhesion of the obtained laminate was measured according to the peeling test of JISK-6301, and the results are also shown in Table 1.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

According to Table 1, in the chlorinated polyethylene and chlorinated ethylene copolymer blend polymer, the addition of quicklime reduces the expansion ratio without lowering the physical properties and the adhesive strength with other rubbers. I understand.

Next, Table 2 shows an example in which an organotin compound was blended to carry out UHF crosslinking, and an example in which this was not blended was compared as a reference example.

[0039]

[Table 5]

It can be seen from Table 2 that the addition of the organotin compound is effective for preventing scorch and lowering the foamability.

[0041]

The cross-linking composition of the present invention comprises a mixture of a chlorinated polyethylene and a chlorinated ethylene-alkyl acrylate copolymer as a main component, and an appropriate amount of quicklime added to the cross-linking component to prepare UHF. The foaming phenomenon at the time of cross-linking can be significantly suppressed, and scorch can be prevented by adding an organic tin compound. That is, by performing UHF cross-linking, excellent cross-linking physical properties and a high degree of continuous productivity can be obtained, and particularly when it is laminated with another kind of rubber, a significantly improved cross-linking adhesiveness can be obtained.
Therefore, it has a great utility value as a laminate that can take advantage of the properties of the double-sided polymer, and particularly has excellent adhesiveness to epichlorohydrin rubber, acrylonitrile rubber, etc., so that fields requiring oil resistance, ozone resistance, heat resistance, etc. For example, it can be effectively used for a fuel hose of an engine part.

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Claims (1)

[Claims] 1. A chlorine content of 2 to 45% by weight, which is obtained by chlorinating an ethylene-alkyl ester copolymer having (a) 5 to 95% by weight of chlorinated polyethylene and 1 to 20% by weight of alkyl acrylate. % Chlorinated copolymer 95 to 5% by weight
100 parts by weight (b) mercaptotriazines 0.1 to 5 parts by weight (c) amine having a boiling point of about 110 ° C. or higher, an organic acid salt of the amine, or an adduct thereof, diarylguanidine, condensation of aniline and aldehyde 0.5 to 3 mol (d) quicklime 1 to 1 mol or more of compounds selected from the product and 2-benzothiazylsulfenamide of primary or secondary amine (d) 1 mol 30 parts by weight (e) 0.1 to ₂ parts by weight of an organic tin compound represented by the following general formula R ₂ SnY or R ₂ SnZ ₂ (wherein R is a C _{1 to} C ₂₀ alkyl group, Y is oxygen or C ₃
To C ₂₀ aliphatic dicarboxylic acid residue, and Z is a C _{1 to} C ₂₀ aliphatic carboxylic acid residue) are crosslinked by microwaves. .