JPH01249848A - Vulcanizable chloorinated polyethylene composition - Google Patents

Abstract

PURPOSE: To provide composition which is obtained by mixing a specified polyhydric alcohol to a rubber-like chlorinated polyethylene containing chlorine, which gives vulcanized materials superior in heat resistance and are suitable for the sheathing of an electric wire and a hose.

CONSTITUTION: (A) A rubber-like chlorinated polyethylene containing 20-50% of chlorine, 35% in a usual case in an amount of 100 wt.% (hereafter %) is mixed with (B) 0.25-10%, preferably 0.75-3%, of a polyhydric alcohol (example: pentaerythritol and the like) which has two and more hydroxyl groups that are three-dimensionally adjacent and whose molecular weight is not more than 600, (C) a basic metal oxide or hydride as an acid acceptor, (D) an amine (derivative), and a vulcanization accelerator such as a phosphonium salt and (E) a crosslinking agent (example; 2,5-dimercapto-1,3,4-thiadiazole) are compounded to obtain the objective composition.

COPYRIGHT: (C)1989,JPO

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to, for example, 2,5-dimercapto-1,3,
Vulcanizable compositions based on rubbery chlorinated polyethylene containing polymercapto compounds such as 4-thiadiazole, aliphatic polyhydroxy compounds, inorganic acid acceptors and quaternary phosphonium or quaternary ammonium salts, or amines .

Prior Art U.S. Pat. No. 4,288,576 discloses the crosslinking of chlorinated polyethylene using 2,5-dimercapto-1,3,4-thiadiazole and basic materials such as amines.

U.S. Pat. No. 4,524,185 describes 2,5-dimercapto-1,3 for improving the properties of halogen-containing rubbers.
, 4-thiadiazole.

U.S. Pat. No. 4,551,505 discloses crosslinking of chlorinated polyethylene with 2,5-dimercapto-1,3,4-thiadiazole in the presence of basic substances.

Japanese Patent Publication No. 57-149357 discloses a chlorine-containing polymer, sulfur and/or sulfur donor, polyhydric hydroxy compound,
A vulcanizable composition comprising a quaternary ammonium salt and/or a quaternary phosphonium salt and calcium hydroxide is disclosed.

Japanese Patent Publication No. 59-227946 discloses a halogen-containing polymer; 2,3-dimercaptopyrazine; 2,3-dimercaptoquinoxaline or a derivative thereof; a quaternary ammonium salt and/or a quaternary phosphonium salt; and an inorganic acid acceptor. vulcanizable compositions are disclosed.

SUMMARY OF THE INVENTION The present invention relates to chlorinated polyolefin compositions that can be vulcanized rapidly and at moderate temperatures to provide vulcanizates with excellent heat resistance.

More particularly, the invention comprises: a) chlorinated polyethylene with a chlorine content of 20 to 50% by weight; b) basic metal oxides or hydroxides as acid acceptors; c) e.g. d) vulcanization initiators, such as certain amine derivatives and phosphonium salts; d) crosslinking agents, such as, for example, 2,5-dimercapto-1,3,4-thiadiazole (DMT) or certain derivatives thereof; and e. ) Vulcanizable chlorinated polyolefin elastomer assemblies based on combinations of aliphatic polyhydric alcohols such as pentaerythritol or sorbitol.

Vulcanizates based on these formulations can be used for the production of electrical wire sheaths and hoses.

DETAILED DESCRIPTION OF THE INVENTION Chlorinated polyethylene can be industrially vulcanized, usually with peroxide, to form a vulcanized product with excellent properties. However, most peroxides are expensive and require high vulcanization temperatures. Therefore,
Commonly used in the rubber industry, e.g. 2.5
-dimercapto-1,3,4-thiadiazole (DMT)
) or sulfur and sulfur-donating compounds have been proposed. However, these formulations proposed for the vulcanization of chlorinated polyethylene have various drawbacks. For example, DMT-based vulcanization requires significant amounts of magnesium oxide or similar acid acceptors, which is detrimental to heat aging.

The present invention provides vulcanizable chlorinated polyethylene compositions with excellent heat resistance.

The chlorinated polyethylene that can be used in the present invention is produced by the reaction of chlorine or a chlorine generator with a hydrocarbon polymer, such as polyethylene or a copolymer of ethylene and a 03-C, alpha olefin. It can be any known elastomer. The polyethylene may be in either a low density-high pressure form or a high density homopolymer or copolymer form produced using coordination catalysts at relatively low pressures. The ethylene copolymer used for chlorination can contain up to about 20% by weight of C1-C8 comonomers. The average molecular weight of the chlorinated polyolefin is usually at least 10.000,
It is obtained by chlorinating polyolefins until the product contains 20-50% by weight of chlorine. Chlorination can be carried out in solution or suspension or in the absence of a liquid reaction medium.

The chlorinated polyethylene used in the present invention is 20% by weight.
Contains ~50% chlorine, typically 35% chlorine,
Therefore, it is rubbery.

The acid acceptor used in the present invention is typically magnesium oxide, but other common basic metal oxides and hydroxides can also be used. The amount of acid receptors is 0.5-2
Although in the range of 0 phr, the preferred amount to provide optimum properties will depend on the particular vulcanization recipe. A sufficient amount of the formulation (1”
(10 phr) of activated polyhydroxy compound, about 2 phr of magnesium oxide is desirable.

A variety of mercapto compounds containing 2 to 4 mercapto" groups and having a molecular weight of less than 500 can be used. Suitable mercapto compounds include 2.5-dimercapto-1,3,4-thiadiazole or its monoester. Another suitable mercapto compound is trithiocyanuric acid. A preferred amount of mercapto compound is t by weight.
0.75 to 3 parts by weight per oos of elastomer. Other crosslinking agents, such as sulfur, can also be used in vulcanization, but give vulcanizates that exhibit poor compressive set and insufficient heat resistance.

The amount of polyhydric alcohol used as a vulcanization aid in the compositions of the present invention is about 0.25% per 100 parts of chlorinated polyethylene.
~IO parts are added to the elastomer formulation, with preferred amounts being 0.75 to 3 parts per 100 parts of elastomer. Polyhydroxy compounds have at least two hydroxyl groups that are sterically close to each other, usually at 1.2 or 1.3 or 1.4 positions with respect to each other, and
It is an aliphatic alcohol with a molecular weight of less than 0.00.

Aliphatic alcohols may be substituted with other groups, such as aromatic or heterocyclic groups. Suitable aliphatic alcohols contain 2 to 12 carbon atoms. 100
When using less than 0.2 parts per part of elastomer,
It has almost no effect on the vulcanization state and heat aging is observed. The amount of polyhydroxy compound is 10
When exceeding 10 copies per 0 copies, no further profit is achieved.

Preferably, the aliphatic polyhydroxy alcohol contains 2 to 6 carbon atoms. Polyhydroxy alcohols that can be used are 2,2-dimethyl-1,3-propanediol, ethylene glycol, glycerin, 1.2
- Propanediol, dipentaerythritol, and pentaerythritol (available as industrial heavy liquor PE-200, commercially available from Percules).

The compositions of the invention must also contain amines, quaternary ammonium or phosphonium compounds as initiators.

Among the most frequently recommended amines are dihydro derivatives of pyridine.

The quaternary ammonium or phosphonium salts used in the present invention are represented by the following general formula: In the above general formula, Z is N or P and iRt, R,
R and R6 may be the same or different and can be selected from C1-17 alkyl, cyclohexyl, phenyl and benzyl groups.

The above 01-17 alkyl groups include, for example, methyl, propyl, butyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl groups, and the like. These quaternary ammonium salts or phosphonium salts may be used alone or as a mixture. Quaternary salts are in particular tetrabutylammonium chloride, benzyltriethylammonium chloride, dodecylpyridinium chloride, tetrabutylhonufonium chloride, triethylhexadecylphosphonium chloride, ethyltrioctylphosphonium chloride, triethylhexylammonium chloride, triglylmethylammonium chloride. etc. Thus, amines useful in the present invention are those that exhibit cationic surface activity. A typical amine suitable for use as an initiator is N-phenyl-3,5-diethyl-2-propyl-1,4-dihydropyridine.

The chlorinated polyethylene compound can and usually does contain conventional fillers, such as carbon black, calcium carbonate or clay, pigments such as titanium dioxide, plasticizers, e.g. fragrances. Family oils or esters are also often present. Their amounts are determined by the intended use of the vulcanizate, but have little bearing on the results of the present invention.

The invention is illustrated by the following examples, in which parts are by weight per 100 parts of chlorinated polyethylene.

Example 1 100 parts of chlorinated polyethylene (35 wt. 11% Cu2
) is commercially available as 30 parts SRF carbon black, 2 parts magnesium oxide, 3 parts "P E 200" pentaerythritol, and 2.5 parts Eco-S.
dimercapto-1,3,4-thiadiazole and 0.8
part of N-phenyl-3,5-diethyl-2-propyl-
1,4-dihydropyridine at 60°C on a rubber roll machine.
and mixed for 4 minutes. The formulation was taken out of the roll machine as a sheet, and test pieces were cut out and then vulcanized under pressure at 160°C. ASTM D-41 stress-strain properties
Measured according to 2. Compressive strain is ASTM D-39
5. Measured according to method B. The results for this example are shown in Table 1 - Example IA.

Three other samples and accompanying specimens were prepared as described for Example IA with the following changes: Sample IB
contained 4 parts of sorbitol instead of pentaerythritol. Sample IC contains 10 parts of magnesium oxide, does not contain "PE-200", and has a sample ID of "P".
The results are shown in Table 1.

Masumasu Homare Example IA represents the invention and shows improvement in heat aging by the addition of pentaerythritol.

In Example IA, 42% of the original elongation at break is retained. This improvement is significant because the improvement in heat resistance is accompanied by the improvement in compressive strain resistance. Example IB shows a formulation containing another polyhydric alcohol, namely sorbitol. Heat aging is outstanding.

Compressive strain is also good. Example 1C represents a typical conventional formulation. After aging at 150° C. for 7 days, the EB retention is only 17%. Some improvement in heat resistance was achieved by increasing the content of magnesium oxide acid acceptor from 10 to 2 p as shown in ID.
hr (although the E retention value of 34% after 7 days is significantly lower than for the compositions of the invention).

Example 2 Additional formulation samples were prepared in the same manner as in Example 1. The results are shown in Table 2.

Table 2 Example 2 people Example 2B Chlorinated polyethylene (35% by weight cA) 100
100SRF Kashibon Black 30
Magnesium 30 oxide 22 parts MT
Derivative book 2.5 2
．． Benzyltriphenylphosphonium pentachloride 1 -Amine Kimoto 0
．． 8″PE-200″ Pentaerythritol 3
3 rotating plate rheometer - 30 minutes/160°CMH (Nm)
4.6 4.6t
'90 (minutes) 6.0
6.5 Eco-S Main powder N-phenyl-3,5-diethyl-2-propyl-
1,4-Dihydropyridine Example 3 This example demonstrates improved heat aging with the addition of pentaerythritol using a phosphonium salt as an initiator. 100 parts by weight of chlorinated polyethylene (35% by weight C2), 30 parts by weight of SRF carbon black,
2.5 parts Echo■S, 2 parts magnesium oxide and 1
A blended sample was prepared in the same manner as in Example 1 by kneading with 30% of benzyltriphenylammonium chloride.

In addition, Example 3B contains 3 parts of pentaerythritol (
of the present invention), but not in Example 3A (control example). The physical properties of both formulations before and after heat aging are shown in Table 3.

Table 3 M, (N,,) 4.1 4.9t
S2 (minutes) 2.7 1.7t' 90 (minutes)
21.57.0 Stress/strain characteristics (vulcanization 30 minutes/160°C) initial value Mlon (psiXMPa) 330 2.3
370 2.5Joo(psiXMPa) 950
6.5 950 6.5T-(psiXMPa
) 3150 21.7 3450 23.8El
(%) 505 515 Heat aging (
7 days/121°C) M,oo (psiXMPa) 480 3.3
400 2.7Ta (psiXIJPa) 3
350 23.1 3450 23.8E8 (%)
470 450E8 retention rate%
9388 Heat aging (70 hours/150°C) M+oo(+)siXMPa) 850 5.9
570 3.9TB (psiXMPa) 255
0 17.6 2650 18.3Ell (%)
210 305 Rate of change from initial value, % M,. . +157 +54T,
-19-23 E, -58' -40,8 The main features and aspects of the present invention are as follows.

19 rubbery chlorinated polyethylene containing 20 to 50% chlorine by weight, and at least two parts by weight of from 0.25 to 10 parts by weight per 100 parts by weight of chlorine A composition comprising a polyhydric alcohol having one hydroxyl group and a molecular weight of less than 600.

2. 0.75 to 3.0 parts by weight of a mercapto compound containing 2 to 4 mercapto groups and having a molecular weight of less than 500 per 100 parts of chlorinated polyethylene is present; The composition according to item 1.

3.0.5 by weight per 100 parts of chlorinated polyethylene
3. The composition of item 2 above, wherein ~20 parts of acid acceptor is present.

4.0.3 by weight per 100 parts of chlorinated polyethylene
4. A composition according to claim 3, wherein ~5 parts of an initiator that is an amine, quaternary ammonium or phosphonium compound is present.

5. The composition according to item 4 above, wherein 0,675 to 3 parts by weight of polyhydric alcohol are present per 100 parts by weight of chlorinated polyethylene.

6. The composition according to item 5 above, wherein the polyhydric alcohol contains 2 to 12 carbon atoms.

7. The composition according to item 6 above, wherein the polyhydric alcohol contains at least two hydroxyl groups in 1,2-11,3- or 1,4-positions with respect to each other.

8. The composition according to item 7 above, wherein the chlorinated polyethylene contains about 351 t% chlorine.

Claims (1)

[Claims] 1. Rubbery chlorinated polyethylene containing 20 to 50% by weight of chlorine, and 0.25 to 10 parts by weight per 100 parts of chlorinated polyethylene of at least sterically adjacent to each other. A composition comprising a polyhydric alcohol having two hydroxyl groups and a molecular weight less than 600.