JPH0241345A - Bloom's improved rubber composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a rubber composition with improved bloom phenomenon. More specifically, ethylene-propylene-tzene terpolymer containing sulfur or sulfur compounds (hereinafter referred to as E
The present invention relates to a rubber composition in which the bloom phenomenon of additives is improved before or after vulcanization of a rubber based on PDM (abbreviated as PDM).

[Conventional technology I EPDM has non-conjugated tsene introduced as the third component, so it can be used for sulfur vulcanization, peroxide vulcanization, quinoid vulcanization,
All types of vulcanization such as resin vulcanization are possible, and any vulcanization method can provide excellent ozone resistance, heat resistance, weather resistance, and the physical properties required for rubber.
It is used in large quantities for automotive industrial products, waterproof sheets, etc.

However, since EPDM has a low content of a non-conjugated diene compound as a third component, the rate of vulcanization is slow, and therefore vulcanization at high temperature and for a long time is required. Generally, in rubber compositions, some of the additives added to the base rubber before molding are deposited on the surface again over time, causing a so-called additive bloom phenomenon. EPr with sulfur vulcanization added)
For the M compound, it is necessary to increase the vulcanization rate for the reasons mentioned above, so other rubber compounds (for example, NR1SB
R, etc.), a wide variety of vulcanization accelerators are used,
Along with this, blooming phenomenon of additives is likely to occur.

In the case of unvulcanized rubber, the blooming phenomenon of additives causes a problem of poor adhesion between processes.

In addition, in the case of vulcanized rubber, it is necessary to avoid this as much as possible, as it impairs the appearance and significantly reduces the commercial value of the product. Although it has been proposed to add an alkyl 7 ether/el resin, the reality is that satisfactory results have not yet been obtained.

[Problems to be Solved by the Invention] In view of the above circumstances, the inventors of the present invention have proposed the following method to solve the problem before or after vulcanization of an EPDM-based rubber containing a vulcanizing agent and optionally a vulcanization accelerator. As a result of a review of personal correspondence, we found that by incorporating a specific proportion of zinc dithiophosphate compounds, we found that:
The inventors have discovered that it is possible to suppress the blooming phenomenon of additives, and have arrived at the present invention.

Means for Solving Problem 1" That is, the present invention provides a rubber based on an ethylene-70 pyrene-diene terpolymer containing a sulfur-based vulcanizing agent and optionally a vulcanization accelerator, Per 100 parts by weight of the base rubber, a zinc dithiophosphate compound represented by the following general formula [N (in formula 11, R1 and R2 represent an alkyl group, an alkenyl group, an alicyclic group, or an aralkyl group) was added to
．． The gist of this invention is a rubber with improved bloom phenomenon characterized by containing 2 to 10.0 parts by weight of l'Lr&.

The present invention will be explained in detail below.

As the base rubber of the rubber composition according to the present invention, EPDM
It is preferable to use it alone, but it may be a mixture of EPDM as a main component and other rubbers. Other rubbers include nitrile rubber (NR), imprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), nitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), etc. It may be one kind or a combination of two or more kinds.

The rubber composition according to the present invention contains a sulfur-based vulcanizing agent.

Sulfur-based vulcanizing agents include sulfur, 4,4゛-dithiodimorpholine, tetraethylthiuram monosulfide, tetraethylthiuram monosulfide, tetrabutylthiuram monosulfide, tetraethylthiuram disulfide,
Examples include tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide, pentamethylenethiuram hexasulfide, but are not limited to these examples.

The amount of the sulfur-based vulcanizing agent added to the base rubber can be selected depending on the type of product to be molded from the rubber composition. Usually, 0.5 to 5 parts per 100 parts by weight of the base rubber.
Selected within the range of heavy IL division.

The rubber composition according to the present invention includes the above-mentioned (1) incorporation into the base rubber.
) is blended with a zinc dithiophosphate compound. Zinc dithiophosphate compounds are used in place of all or part of the conventional vulcanization accelerators that are blended into the base rubber, but since they have a vulcanization accelerating effect and have high solubility in the base rubber, they are Rubber compositions containing a zinc dithiophosphate compound or both thereof and a conventional vulcanization accelerator exhibit a significant improvement in the plume phenomenon of additives as a whole.

In the present invention, examples of the zinc dithiophosphate compound represented by the above-mentioned (r) include the following.

Examples of compounds in which substituents R1 and R3 are alkyl groups: oto'-zinc methyldithiophosphate; o, o'-
Zinc diethyldithiophosphate; o,o'-biX(9,
10-nochlorooctadecyl)zinc notothiophosphate; o,
o'-bis(1,3-trimethylbutyl)zinc dithiophosphate: o,o'-bis(2-ethylhexyl)zinc dithiophosphate; o,O'-bis(4-methylpentyl)zinc dithiophosphate: o,o' -G-Lobe Chill-
Zinc dithiophosphate; o-2 ethylhexyl-〇-imptylnotothiophosphate; 0-2 ethylhexyl, l
- Zinc isopropyldithiophosphate: oto'-Zinc dioctyldithiophosphate: O,Ol-zinc dilauryldithiophosphate Examples of compounds in which substituents R1 and R2 are alkenyl groups: o,o'-bis(2-propenyl)dithiophosphate Examples of compounds in which the zinc substituents R1 and R2 are 7ralkyl groups: o,o'-bis(bennol)dithiophosphate zinc substituent R
7. Examples of compounds in which R2 is an alicyclic group: o, o' -(
Methylcyclohexyl)dithiophosphorous acid IQ; o
, o' (methylcyclopentyl)zinc dithiophosphate The addition ratio of the above zinc dithiophosphate compound to the base rubber is 0.2 to 100 parts by weight per 100 parts by weight of the base rubber.
This is the range of the lfi part. If the amount added is less than 0.2 parts by weight, the amount to replace the conventional vulcanization accelerator is too small and the effect of suppressing the bloom phenomenon of the additive in the rubber composition is not exhibited, which is not preferable. If the amount exceeds 1.0 parts, the effect will not be significantly improved even though the amount added is increased, and on the contrary, the cost will increase, which is not preferable.

The rubber composition according to the present invention may contain a vulcanization accelerator.

As a vulcanization accelerator, the following general formula (rl)'(Vl)
Examples include compounds represented by, but are not limited to these examples.

- A sul7enamide vulcanization accelerator represented by the following formula [(■) in which R3 and R2 represent a hydrogen atom, a furkyl group, an alkenyl group, an alicyclic group, or an aralkyl group].

Specific examples include N-cyclohexyl-2-benzothiazolesulfenamide): N-t-butyl-2-benzothiazolesulfenamide; N-oxynoethylene-
2-benzothiazolesulfenamide; N, N'
-noisoprobyl-2=benzothiazolesulfenamide; N,N'-nocyclohexyl-2-benzothiazolesulfenamide: N-t-cyclohexyl-2
-benzothiazole sulfenamide and the like.

- Installation [(■) A thiuram-based vulcanization accelerator represented by 61, where R represents an alkyl group, alkenyl group, alicyclic group, or aralkyl group, and X represents an integer of 1 to 10.

Specific examples include tetramethylthiuramnosulfur;
Tetraethylthiuram disulfide; tetraethylthiuram disulfide; tetramethylthiuram mo7 sulfide; tetraethylthiuram monosulfide; tetrabutylthiuram moresulfide; dipentamethylenethiuram tetrasulfide; dipentamethylenethiuram hexasulfide V and the like.

General formula [(■) In the formula, R1 and R2 represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, or an aryl group, M is a divalent metal atom, and jl is 1 to 4 indicates an integer. A dithiocarbamic acid-based vulcanization accelerator represented by 1.

Specific examples include zinc salts of nomethylnotiorubamic acid; zinc salts of noethyldithiorubamates;
Zinc salt of butyldithiocarbamic acid; Zinc salt of ethyl 7enyldithiocarbamic acid; Zinc salt of N-pentamethylenetthiocarbamic acid; Zinc salt of dibenzothiazildithiocarbamic acid; Iron salt of nomethylnotiocarbamic acid; Noethyldithiocarbamic acid iron salt;
- Iron salt of butylnotiocarbamic acid; Copper salt of nomethylnotiocarbamic acid; Copper salt of noethylnotiocarbamic acid; Copper salt of non-n-butylnotiocarbamic acid;
Sodium salt of nomethylnotiocarbamic acid; Sodium salt of noethyldithiocarbamic acid; Sodium salt of no-11-butyldithiocarbamic acid; Tellurium salt of nomethylnotiorubamic acid; Tellurium salt of noethylnotiorubamic acid; Examples include tellurium salt.

General formula [(■) In the formula, R is a hydrogen atom, a 2-thiobenzothiazole group, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, an aryol group, an aliphatic monoamine 7 group, or a monovalent The metal atom and n represent an integer of 1 or 2. A thiazole-based vulcanization accelerator represented by 1.

Specific examples include 2-mercaptobenzothiazole;
Sodium salt of dibenzothianol disulfide captobenzothiazole; Zinc salt of 2-mercaptobenzothiazole; 2-(2,4-dinitrophenylthio)benzothiazole; 2-(N.N'-noethylthiorubamoylthio)benzothiazole; Examples include 2-(4-morpholizthio)benzothiazole.

-Incorporation [(■) In the formula, R1 and R2 represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, an aralkyl group, or an aryl group. A guanidine-based vulcanization accelerator represented by 1.

Specific examples include diphenylguaninone;
Examples thereof include lylguaninone; o-tolylbiguanidine; di-0-tolylguanidine salt of dicatechol borate, and the like.

The amount of the vulcanization accelerator to be blended into the base rubber can be selected depending on the type and amount of the vulcanizing agent blended into the base rubber, and the type of product to be molded from the rubber composition. Usually, the amount is selected in the range of 3 to 7 parts by weight based on 100 parts by weight of the base rubber.

In addition to the sulfur-based vulcanizing agent, zinc dithiophosphate compound, and vulcanization accelerator, the rubber composition according to the present invention contains colorants such as carbon black, fillers such as calcium carbonate, paraffin oil, etc. Activators such as zinc white, stearic acid, and the like can be included.

To obtain the rubber composition according to the present invention, first, a coloring agent, filler, paraffin oil, zinc white, stearic acid, etc. are mixed with a base rubber, and the mixture is kneaded at a low temperature using a kneading machine such as a closed mixer. Adjust the prepared EPDM masterbatch. Next, a sulfur-based vulcanizing agent, a zinc dithiophosphate compound,
If necessary, other vulcanization accelerators are weighed in predetermined amounts, mixed into a masterbatch, and kneaded at a temperature at which no vulcanization reaction occurs. Using this unvulcanized rubber composition as a raw material, the desired product can be obtained by heating and vulcanizing it using a vulcanization mold or the like.

Products obtained from the rubber composition according to the present invention include roofing, weather strips, hoses, etc.

"Effects of the Invention" As described above, the present invention is characterized by blending a specific proportion of a zinc dithiophosphate compound into a rubber based on EPDM containing a sulfur-based vulcanizing agent and optionally a vulcanization accelerator. This greatly improves the conventional plume phenomenon of additives in the rubber composition before or after vulcanization, and its industrial utility value is extremely large.

"Examples" Next, the present invention will be described in detail based on Examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Examples 1-3, Comparative Examples 1-5 First, the following ingredients were weighed in the following proportions.

EPDM 100 parts by weight Carbon black 15 () Paraffin oil 80 Zinc white
5 Stearic acid
1. Heat each of the above components to 70°C using a closed crosstalk method.
The mixture was kneaded at a temperature of 3.5 minutes to obtain an EPDM masterbatch.

The EPDM masterbatch obtained by the above method was mixed with sulfur, a vulcanization accelerator, and a zinc dithiophosphate compound in the proportions shown in Table 1, and heated at 70°C using an open roll. An unvulcanized rubber composition was obtained by kneading at a temperature of .

The physical properties of this unvulcanized rubber composition were evaluated in the following manner. The results are shown in Table 1.

(1) Plume test A method in which unvulcanized rubber is left at room temperature for 10 days, and then the degree of precipitation of additives on the rubber surface is observed with the naked eye. The judgment criteria based on observation were as follows.

◎: No plume phenomenon observed at all.

O: Slight plume phenomenon is observed.

Δ: Plume phenomenon is observed.

×: Plume phenomenon is evident.

(2) Mooney Scorch Test Based on JIS 63005, the ease of burning of rubber was measured at a measurement temperature of 125°C. The larger the value of , the more difficult the rubber composition is to burn out, which is preferable.

(3) ODR The vulcanization time was measured at a measurement temperature of 160°C in accordance with ASTM D-2084. The smaller the value of t9Q, the easier it is to vulcanize the rubber composition.

The above-mentioned unvulcanized rubber composition was supplied to a vulcanizing press, and
The rubber composition was vulcanized by tso vulcanization at a temperature of .degree.

The physical properties of the obtained vulcanized rubber composition were evaluated by the following methods. The results are shown in Table 1.

(4) Plume test In the example described in (1) above, the test and judgment were made in the same manner as on the same side except that the unvulcanized rubber was replaced with vulcanized rubber.

(5) Physical properties of vulcanized rubber The physical properties were measured using a No. 3 dumbbell in accordance with JIS K 6301. T is the tensile strength at break, E
indicates the elongation rate at break.

(6) Heat aging resistance test Place a No. 3 dumbbell in a tube tester, seal it, and
After heating at a temperature of 'C for 7 days, JISK 630
T and E were measured according to 1 and expressed as a rate of change (%) with respect to the value before heating.

[Note 1 Book 1: The numerical value means a weight of 11g.

Book 2 o,o'-no-butyldithiophosphate zinc.

Book 3 N-cyclohexyl-2-benzothiazolesulfenamide.

Book 4 Tetramethylthiuramtetra sulfide.

Car 5 Tetramethylenethiuram tetra sulfide.

Car 6 Zinc nomethylnotiocarbamate.

From Table 1 above, the following becomes clear.

(1) The rubber JIIJl& product according to the present invention does not cause the plume phenomenon of additives either before or after vulcanization (
(See Examples 1 to 3 and Comparative Examples 1 to 5).

(2) When other vulcanization accelerators are used in addition to the zinc dithiophosphate compound, the physical properties of the rubber become better than when they are not used together (see Examples 1 to 3).

(3) The rubber composition according to the present invention has the physical properties of the unvulcanized rubber, the physical properties of the vulcanized rubber, the results of the heat aging resistance test, etc., which are not significantly different from those of the comparative example, and contains a zinc dithiophosphate compound. As a result, the various physical properties originally possessed by rubber are not impaired (see Examples 1 to 3 and Comparative Example 1 to 5).

Applicant: Misara Monsanto Kasei Co., Ltd.

Claims (2)

[Claims] (1) The following general formula (I ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [In the formula (I), R_1 and R_2 are alkyl groups,
Indicates an alkenyl group, an alicyclic group, or an aralkyl group. ] 0.2 to 10
．． A rubber composition with improved bloom phenomenon, characterized in that it contains 0 parts by weight. (2) The rubber composition according to claim 1, wherein the vulcanization accelerator contains one or more compounds selected from the following general formulas (II) to (VI). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) [In formula (II), R_1 and R_2 represent a hydrogen atom, an alkyl group, an alkenyl group, an alicyclic group, or an aralkyl group. ] Sulfenamide vulcanization accelerator ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ... (III) [In the formula (III), R is an alkyl group, an alkenyl group, an alicyclic group, or an aralkyl group and x represents an integer from 1 to 10. ] Thiuram-based vulcanization accelerator ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (IV) [In the formula (IV), R_1 and R_2 are hydrogen atoms, alkyl groups, alkenyl groups, alicyclic groups group, an aralkyl group, or an aryl group, M represents a divalent metal atom, and n represents an integer of 1 to 4. Dithiocarbamic acid vulcanization accelerator represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ... (V) [In the formula (V), R is a hydrogen atom, 2-thiobenzothiazole group, alkyl group, alkenyl group, an alicyclic group, an aralkyl group, an aryl group, an aliphatic monoamino group, or a monovalent metal atom; n represents an integer of 1 or 2; ] Thiazole-based vulcanization accelerator ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (VI) [In the formula (VI), R_1 and R_2 are hydrogen atoms, alkyl groups, alkenyl groups, alicyclic groups , represents an aralkyl group or an aryl group. ] Guanidine-based vulcanization accelerator