EP0569995B1

7/25/2019 EP0569995B1

1/18

(19)

Europaisches

Patentamt

European

Patent Office

Office

europeen

des brevets

(12)

peen

des brevets

E P 0 5 6 9 9 9 5 B 1

EUROPEAN PATENT SPECI FICAT ION

(45)

Date of

publication

and mention

of the

grant

of the

patent:

16.12.1998 Bulletin 1998/51

(21)

Application

number: 93107840.6

(22)

Date of

filing:

13.05.1993

(51)

intci.6:

C 0 8 K 5 / 0 0 , C 0 8 K 5 / 4 4 ,

C08L 21/00

(54)

Scorch retardant

compositions

for

peroxide

curable elastomers

Mischungen zur Verzogerung

der Vorvulkanisation fur

peroxidhartbare

Elastomere

Melanges anti-grilleurs

pour

des elastomeres durcissables

par

les

peroxides

DO

lO

O)

O)

O)

CO

LO

o

a .

LU

(84)

Designated Contracting

States:

BE DE ES FR GB IT NL SE

(30)

Priority:

14.05.1992 US 883333

(43)

Date of

publication

of

application:

18.11.1993 Bulletin 1993/46

(73)

Proprietor:

CRAY VALLEY SA

92800 Puteaux

(FR)

(72)

Inventors:

Knowles,

Eric

Thornton

Cleveleys,

Lanes. FY5 3JD

(GB)

Cornforth,

David Arthur

Rochdale,

Lancashire OL12-7RU

(GB)

Carney,

Francis Michael

Crumpsall,

Manchester M8 7WR

(GB)

(74)

Representative:

Chaillot,

Genevieve

Cabinet

CHAILLOT,

16-20,

avenue

de L

Agent

Sarre,

B.P. 74

92703 Colombes Cedex

(FR)

(56)

References cited:

EP-A- 0 346 863

US-A- 3 993 633

EP-A- 0 504 920

Note: Within nine months from the

publication

of the mention of the

grant

of the

European

patent,

any person may

give

notice

to

the

European

Patent Office of

opposition

to

the

European

patent

granted.

Notice of

opposition

shall be filed in

a

written reasoned

statement.

It shall

not

be deemed

to

have been filed until the

opposition

fee has been

paid. (Art.

99(1) European

Patent

Convention).

Printed

by

Jouve,

75001 PARIS

(FR)

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EP 0 569 995 B1

Description

FIELD OF THE INVENTION

5

This invention is directed

to

scorch retardant

compositions

suited for the vulcanization of elastomers.

DESCRIPTION OF THE PRIOR ART

The

use

of

polyunsaturated

monomers,

and

particularly polyfunctional (meth)acrylate monomer

systems,

for the

10

curing

and vulcanization of

peroxide-curable

elastomers

to

enhance

physical properties

of the

resulting

elastomers is

known. Such

property

enhancements include

high

hardness,

resistance

to

attack

by sunlight, hydrocarbon

solvents

as

well

as water, physical strength

and

aging.

Free-radical reaction of the

polyunsaturated monomers

with the elasto-

meric

compositions

is conducted

at

elevated

temperatures

wherein the

polyunsaturated compositions

crosslinkth

rough

an

abstractable

hydrogen

atom

on

the elastomer.

is

Scorching

is

a problem

associated with the

curing

of the elastomers in the

presence

of

peroxide

and

scorching,

in

effect,

is the result of

prevulcanization

of the elastomer. In

prevulcanization

the

monomer

crosslinks with the elas-

tomer at

low

temperature

resulting

in

products

which have

a rough texture, a

shriveled

appearance

and its surface

appearance

is

lumpy.

Thus,

they are unacceptable.

To combat the

problem

of

prevulcanization

and

scorching

of the

elastomer,

it has been

customary

to

add scorch retardants

to

the

polyunsaturated monomer

which in

turn

retard the

20

rate

of

crosslinking

between the elastomer and


at

low

temperature.

Although

many

types

of scorch retardants have been incorporated into the polyunsaturated monomers for subsequent peroxide curing of

elastomers,

there have been

problems.

In

terms

of elastomer

properties,

the addition of the scorch retardants have

been

relatively

ineffective

during high

temperature

vulcanization

or

too

effective in that

they

have retarded vulcanization

to

the

extent

that the

resulting

elastomers do

not

have the

required physical properties.

For

example

many

have reduced

25

elastic modulus and increased

elongation.

In

terms

of

processing

the

elastomers,

the scorch retardants often have

extended the

cure

times

to

such

an

extent

that

costs

become

prohibitive

or,

because of their

volatility,

present

envi-

ronmental

problems

in the

workplace

due

to

odor and

toxicity.

Several

patents

which disclose scorch retardant

systems

for

inhibiting prevulcanization

of elastomers

including

rubber and rubber

type

compositions are as

follows:

30

U.S.

3,751 ,378

discloses

a

mechanism for

inhibiting prevulcanization

of rubber crosslinked with

a polyfunctional

methacrylate

in the

presence

of

peroxide.

Ascorch retardant of

N-nitrosodiarylamine or

N,N'-dinitrosodiphenyl-j>phe-

nylenediamine

is shown.

U.S.

4,857,571

discloses

a

method for the

inhibiting

the

prevulcanization during

free-radical

curing

of rubbers. The

prior art

section of the

patent

discloses that it

was

known

to use

acidic materials such

as phthalic anhydride, salicylic

35

acid and sodium

acetate

which

act

as

retarders in sulfur vulcanization

systems.

Other known retarders include nitroso

and nitroaromatic amines

as

well

as

various

quinones

e.g.

p-benzoquinone

and

naphthoquinone.

Retarders used

by

the

patentees

include modified

alkyl-substituted aminoalkylphenols, an example

of which is

2,6-di-t-butyl-4-[methyl

(phenyl)amino]-n-propylphenol.

U.S.

954,907

discloses

a

method for

avoiding scorching

of

ethylene polymer

based

compositions

vulcanized in

40

the

presence

of

organic peroxide.

The

patentees

disclose the

use

of monofunctional

vinyl compositions as a

scorch

retarding

agent.

Antioxidants such

as sterically

hindered

phenols are

also

suggested as an adjuvant.

U.S.

3,578,647

discloses

a

scorch

prevention

process

for

producing ethylene-containing polymers

crosslinked

by

free radical

generating crosslinking

agents.

The

patentees

employ

the

use

of

a

chain transfer

agent

e.g.,

mercaptans

and

aldehydes as a

scorch

retarding or

scorch

preventing adjuvant.

45

U.S.

3,335,124

discloses method for

controlling

the

rate

of vulcanization of

polyethylene through

the

use

of

a

crosslinking regulator

which heretofore

were

utilized

or

antioxidants. Various

compositions having

antioxidant

activity

and suited

as a crosslinking regulator

include aromatic

amines,

phenolic compounds

and

ketone-aldehyde

condensa-

tion

products.

U.S.

3,202,648

discloses the addition of scorch

inhibiting

components

during

the free radical

peroxide crosslinking

so

of

polyethylene. Alkyl, cycloalkyl

and

arylalkyl

nitrites

having

from

5 to

18 carbon

atoms

are

used

as

the scorch

pre-

venting

additive.

EP-A-0 346 863 relates

to

a

mixture

containing

at

least

one organic peroxide

suitable for the

crosslinking

of

polymers

;

at

least

one hydroquinone

derivative

;

and

at

least

one crosslinking reinforcing

agent,

said mixture

permitting

the

crosslinking

of

polymers

while

extending

the scorch time.

55

US-A-3 993 633 describes

a

class of

2-(1 (2H)-phthalazinone)

sulfenamides useful

as

inhibitors of

premature

vul-

canization of rubber.

2

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SUMMARY OF THE INVENTION

This invention relates

to

a polyfunctional (meth)acrylate

based scorch retardant formulation for

use as a

crosslinker

system

for the

peroxide curing

of elastomer

compositions

vulcanizable in the

presence

of the

peroxide catalyst

and

to

5

the curable elastomer

system

itself. The

improved

scorch

retarding polyfunctional (meth)acrylate

system

comprises:

a polyfunctional (meth)acrylate

and

an

effective

amount

of

a

scorch retardant mixture

comprising hydroquinone

and

a

sulfenamide. Scorch

retarding

curable elastomers

are

formed

by incorporating

the

polyfunctional (meth)acrylate

based

scorch retardant formulations into a peroxide-curable elastomer system. There are several advantages associated

with the


based scorch retardant

compositions

and the curable elastomers

prepared

there-

to

from and these include:

an ability

to

formulate

an easily

handled scorch retardant


system

for

vulcanizing

peroxide-curable

elastomers;

an ability

to

formulate

storageable,

scorch retardant


systems

suited for

forming

per-

15

oxide-curable

compositions;

an ability

to

retard

scorching

of

peroxide-curable

elastomers

during crosslinking

with


monomers

while

maintaining

excellent

rates

of

cure

at

vulcanization

temperatures;

and

an ability

to

inhibit scorch in the vulcanization of

peroxide-curable

elastomers reacted with

polyfunctional (meth)

acrylates

without

significant

environmental

problems

due

to

offensive odors and

particularly

offensive

toxicity.

20

Afirst subject-matter of the present invention is a scorch retarding polyunsaturated monomer containing system

suited for

curing peroxide

curable elastomers and

polyethylene, polypropylene, copolymers containing ethylene

units

and

copolymers containing propylene

units,

which

comprises polyunsaturated

monomer,

0.2

to

6

weight

percent

hyd-

roquinone

based

upon

said


and

1 to

50

weight

percent

sulfenamide based

upon

said

pol-

25

yunsaturated monomer.

Asecond

subject

matter

of the

present

invention is

a

curable

composition comprising an

elastomer

or polyethylene

or polypropylene or a copolymer containing ethylene

units

or a copolymer containing propylene

units

having an

ab-

stractable

hydrogen

atom

crosslinkable with

a polyfunctional (meth)acrylate, polyfunctional (meth)acrylate, organic

peroxide,

and

a

scorch

retarding

additive which

comprises

from 0.2

to 6%

by weight

of

hydroquinone

based

upon

said

30


and from

1 to 50%

by weight

of

a

sulfenamide based

upon

said


acrylate.

DETAILED DESCRIPTION OF THE INVENTION

35

This invention

pertains

to

compositions

suited for

inhibiting or retarding

the

prevulcanization or scorching

of

per-

oxide-curable elastomers

during cure

with

polyinsaturated monomers.

The curable elastomers which

are

crosslinked

with the

polyunsaturated monomers are

elastomeric

organic high polymers,

e.g.,

rubbers which

are

curable via free-

radical

crosslinking

with

polymerizable vinyl

unsaturated

monomers.

In

general,

the free-radical curable elastomers

are polymers having

extractable

hydrogen

atoms

which

on

reaction with the

polymerizable monomers crosslinkthrough

40

carbon-carbon bonds.

Representative examples

of

synthetic rubbery polymers

formed via the

polymerization

of

con-

jugated

dienes,

include

polyisoprene, styrene-butadiene

rubbers,

polybutadiene

rubbers,

neoprene,

and substituted

butyl

rubbers,

chlorinated

polyethylene

rubber. Other elastomers

are

based

upon

vinyl polymerization

and include

polymers

such

as ethylene-propylene

rubbers,

butadiene-acrylonitrile

elastomers,

and silicone elastomers. This inven-

tion

pertains

also

to

compositions

mited for

inhibiting or retarding

the

prevulcanization or searching

of

peroxide-curable

45

polyethylene, polypropylene

and

copolymers containing ethylene

and

propylene

units

e.g.

ethylene-vinyl

acetate

co-

polymers.

The

patents

described in the

prior

art

section herein

suggest

many

representative

elastomer

systems.

The scorch

retarding

curatives for

peroxide

curable elastomers

comprise a polyfunctional

unsaturated

monomer,

typically a polyfunctional (meth)acrylate

monomer,

and

an

effective

amount

of

a

scorch retardant inhibitor and vulcan-

izate

accelerator,

the scorch retarder

being hydroquinone

and the vulcanizate accelerator

being a

sulfenamide. The

so

polyfunctional

unsaturated

monomer generally

is admixed with the scorch retardant additives and

generally

it is

a

component

of the scorch

retarding

curative;

it is

polyfunctional

in that it has

a plurality

of unsaturation units for crosslink-

ing

with the elastomers.

Preferably

it is

a liquid

at

temperatures

below about 50C. The

use

of

polyacrylates

in the

vulcanization of

peroxide

curable elastomers is conventional.

Examples

of

polyfunctional acrylates

include those

acrylic

and

methacrylic

acid

esters

of

C2.12

polyols

and

alkoxylated

derivatives

containing

from 2-6

alkyleneoxide

units. Pref-

55

erably

the

polyols

have from 2-8 carbon

atoms

and

preferably they are

diols and triols.

Specific polyfunctional (meth)

acrylates are : trimethylolethane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethylacrylate,

glycerol trimethyacrylate, glycerol triacrylate, 1,3-butylene glycol dimethylacrylate, ethylene glycol dimethacrylate,

1,4-butylene glycol dimethacrylate, polyethylene glycol dimethacrylate.

3

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Other


which

may

be used

by

themselves

or

in combination with the

polyfunctional

(meth)acrylates

include the

polyallyl

derivatives of

polyols,

such

as,

the

allylic

ethers of

trimethylolpropane,

pentaer-

ythritol, ethylene glycol, glycerol, polyethylene glycol

and

polypropylene glycol

;

triallylmellitate, diallylphthalate,

dial-

lylchlorendate, triallylcyanurate,

and

triallylisocyanurate,

5

One

component

of the scorch retardant

system

is

an organosulfenamide.

These

compounds

have been used in

rubber formulations

as delayed

action accelators. The sulfenamides

are represented by

the formulas:

I

10

wherein

30

RisuptoC10;

R-i

is

H,

C-|.10

aliphatic, aryl, cycloalkyl or aralkyl;

R2

is

C-_

10

aliphatic, aryl, cycloalkyl or aralkyl, or

combined with

R-,

forming a heterocyclic

group;

and,

X is

hydrogen, halogen, hydroxy,

C-,.6

lower

alkyl,

C-,.6

alkoxy.

35

Examples

include

N,N-dicyclohexylbenzothiazolesulfenamide;

N,N-diisopropyl-2-benzothiazolesulfenamide;

2-(4-morpholino)thiobenzothiazole (MTB);

40

N-t-butyl-2-benzothiazolesulfenamide;

and

N-cyclohexyl-2-benzothiazolesulfenamide.

Another

component

of the scorch retardant

system

is

hydroquinone.

In the

past,

quinones

have been used

as

shortstop

agents

in

polymerization

processes, e.g.

in the

polymerization

of olefins such

as

butadiene and

styrene.

45

Other

quinones or polymerization

inhibitor,

even though they

act to

retard the

rate

of

vulcanization,

do

not

give

the

desired result when combined with the sulfenamide

during

the

peroxide curing

of elastomer with

polyacrylates.

One

highly acceptable

method for

incorporating

the scorch retardant additive for

curing

of the elastomer involves

mixing

the

hydroquinone

and sulfenamide with the

polyacrylate

and then

coating

the

resulting liquid

mixture

onto

an

inert solid

phase

substrate. The material then

can

be

packaged

and stored for extended

periods

of time

at

ambient

so

temperatures.

Examples

of substrates suited for

coating

the mixture of

polyacrylates monomers

and scorch retardants

include

powdered

silica,

diatomaceous earth and

clays.

The scorch retardant

system

of

hydroquinone

and sulfenamide also

can

be added

separately or jointly

to

the

elastomer

during milling

with the

polyunsaturated monomer.

However,

it is

preferred

that the scorch retardant additives

be mixed with the


and the resultant mixture added

to

the elastomer.

55

The scorch resistant

polyunsaturated monomer or polyf unctional(meth)acrylate

systems

for

effecting

vulcanization

of curable elastomeric

organic high polymers typically are

formulated

on

the basis of

one

hundred

weight

parts

mon-

omer,

e.g.,

polyfunctional(meth)acrylate.


system

then is

incorporated

into the curable elastomer

in conventional

amounts

from about 0.5

to

50

weight

parts


per

one

hundred

weight

parts

4

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elastomer.

(These

values

may

be

expressed as weight percent.)

When

using polyallylic

functional

monomers,

higher

levels

may

be used than when

using polyacrylates.

For

polyfunctional(meth)acrylates

the level of

polyfunctional(meth)

acrylate

vis-a-vis the curable elastomer

generally

is from

1 to

50

parts

per

100

parts

elastomer.

Higher

levels

may

be

used but seldom

are

for

reasons

of

cost;

the addition level is

primarily

at

the discretion of the formulator and thus

5

depends on

the

nature

of the elastomer

to

be

produced.

In

formulating

the scorch retardant

system

the

range

of

hyd-

roquinone

based

upon

polyfunctional(meth)acrylate

is from 0.2

to

6

parts

by weight

per

one

hundred

parts

by weight

polyf unctional(meth)acrylate.

The sulfenamide also

present

in

a proportion

of from about

1to

30

typically

2

to

20

weight

parts per 100 weight parts of polyf unctional(meth)acrylate. When less than about 0.2 parts hydroquinone are used in

the scorch retardant

polyfunctional(meth)acrylate

system,

there

may

be insufficient inhibitor

to

prevent

even

modest

10

levels of

scorching during cure. Higher

levels

may

be

required depending

upon

vulcanization

temperatures

and vul-

canization times

as

well

as

the elastomeric

organic high polymers

and

polyunsatured momomers

themselves. Too

much

hydroquinone

may

overly

extend

cure cycles

and result in

insufficiently

cured elastomers.

Typically,

the vulcanization

or crosslinking

of the curable elastomers is effected

through

free radical initiation

by

the addition of

a

free-radical

generating compound or

via

a

radiation

source,

e.g.,

a high

energy

electron

source.

is

Although

many

systems

will

cure

at

high

temperature,

high

temperatures

may

result in

unacceptable product

if

cure

temperature

is

too

high. Generally,

then

polymerization

is effected

by initiating

reaction

through

the addition of

a

free

radical

generating compound

which is

usually an organic peroxide. Organic peroxides

suited for

abstracting hydrogen

from the elastomer

are

known and those

conventionally

used

can

be used in the

practice

of this invention for

vulcanizing

elastomers.

Organic peroxides

which

can

be used include

ditertiary peroxides

and these include

benzoyl peroxide,

20

1

,3-bis-t-butylperoxyisopropylbenzene;

1

,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane; 2,5-dimethyl-2,5-bis(t-

butylperoxy)hexane; di-a-cumyl peroxide; and ditertiary peroxides such as di(tert-peroxy)butane; tert-butyl-methylcy-

clohexyl peroxide

and

dibenzoyl peroxide.

Other

peroxides

include

tert-butyl perbenzoate

and

tert-butyl perphthalate.

Radiation of the

polymers

would be

an acceptable

method

depending on use

and

cost

over

chemical free radical

initatiors.

However,

any

conventional

process may

be used.

25

The elastomeric

compositions can

be

processed

in conventional

manner typically involving

the

milling

of

a mas-

terbatch formulations in roll mills and then

curing

the milled masterbatch in molds

or

presses.

Various additives

can

be added

to

the elastomer for

imparting

desirable

properties

thereto and

examples

of additives include carbon

black,

antioxidants,

wetting

agents

and

reinforcing pigments

and fillers.

Examples

of reinforcement and fillers include fine

particles,

zinc

oxide,

calcium

carbonate,

calcium

silicate,

amorphous hydrated

silica,

fine

clays, magnesium

carbonate

30

and carbon black. The addition of various additives

to

achieve desired

properties

is

at

the discretion of the

processor.

The

following examples are provided

and illustrate various embodiments of the invention and

provide comparisons

against

the

prior

art.

EXAMPLE

1

35

Scorch Retardant

Systems

for Elastomers Effect of Level of Scorch Retardent

Vulcanization of


rubbers

was

carried

out

in conventional

manner

in

a

roll mill and then

placing

the milled

system

into

a

mold.

Varying

levels of scorch

retarding

additives of

hydroquinone

and sulfenamide

40

were compared.


systems

were

formulated

by mixing

the

hydroquinone

and sulfenamide with the

trimethylolpropane triacrylate

and

coating

the

resulting

mixture

onto

powdered

silica. Scorch time

to

determine

cure

characteristics

was

evaluated

on

the basis of

Mooney

scorch time

according

to

ASTM 1646-80. The formulations

were

cured

at 1

60C and

physical properties

i.e. hardness measured. The conditions and results

are

set

forth in Table

1

.

The masterbatch formulation is

as

follows:

45

Parts

(by wt)

NBR N367C70 Nitrile Rubber 100

FEF Carbon Black N550 40

Zinc Oxide

5

Stearic Acid

1

Trimethylolpropane Trimethacrylate

15

Vulcup

40KE

(peroxide)

5

N-t-butylbenzothiazolesulfenamide

TABLE

1

Hydroquinone

TABLE

1

Nitrile Rubber is

a butadiene-acrylonitrile

rubber

Vulcup

40KE is

1

,3-bis-t-butylperoxyisopropylbenzene

at 40%

activity

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TABLE

1

SULFENAMIDE* HYOROQUINONE*

SCORCH TIME AT 121 C

(min)

IRHD HARDNESS

1 1

48 76.5

0.5

1 54 74.5

1

0.5 48 79

0.5 0.5 47 78.5

1

0.25 49.5 84

0.5 0.25 43.5 85

TABLE

1

shows

a

combination of both additives

yields

desirable

products.

A level of

hydroquinone or

less than

0.5%

by weight

of the

trimethylolpropane trimethacrylate provided higher

hardness levels in the cured

elastomer,

al-

though

all levels

are acceptable.

EXAMPLE 2

(comparative)

Elastomers Cured with Trial

lylcyan

urate

(TAC)

No Sulfenamide

The

procedure

of

Example

1

was repeated using

the

following

masterbatch formulation. No sulfenamide

was

used

in the cure and delayed action was sought to be achieved through addition of hydroquinone to the methacrylate mon-

omer.

The scorch

retarding

monomer,

TAC,

was

also tested for

comparison.

Vistalon 7500 EPDM 100 PTS

FEF Carbon Black N550

1

00

Struckpar

2280 Process Oil

45

Antioxidant

TMQ 1

Trimethylolpropane trimethacrylate

2

Vulcup

40KE

(peroxide)

5

Vistalon 7500 EPDM is

an ethylene/propylene

rubber which is

commercially

avail-

able.

TMQ

antioxidant is

polymerized trimethyldihydroquinone.

Additions of

hydroquinone expressed as weight

percent

of the

trimethylolpropane trimethacrylate

co-agent

gave

results

as

follows:

TABLE 2

HQ

LEVEL TAC SCORCH TIME AT

1

31C

(min)

HARDNESS

1.07%

-

11

56

12.5%

-

12.5 56

2 27

55

As

can

be

seen

from Table

2,

when 2

parts

TAC

were

used

as

the

coagent

(with no

added scorch

retardant),

the

elastomer had

a

scorch time of 27 min and

a

hardness of

55.

When the

methacrylates were

used,

the addition of

hydroquinone as the sole scorch retarder failed to give as good as a scorch retardant.

EXAMPLE 3

Ethylene-Propylene

Rubbers

The

procedure

of

Example

2

was repeated

except

sulfenamide

was

added

along

with

polyacrylate

and

hydroqui-

none

in

forming

the

co-agent

formulation. Table 3

provides

data

at 5

parts

and 3

parts


as

follows. The masterbatch formulation

was comprised:

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Parts

(by wt)

Keltan 4802 EPDM 100

FEF Black 85

Sunpar

2280 Process Oil 30

Antioxidant

TMQ 1

N-t-butylbenzothiazole sulfenamide Table 3

Vulcup

40KE 9

Hydroquinone

1.7

Kelton 4802 is

an ethylene/propylene

rubber which is

commercially

avail-

able.

TABLE 3

20

TRIMETHYLOLPROPANE TRIMETHACRYLATE

CO-AGENT

5

PTS

SULFENAMIDE LEVEL SCORCH TIME AT 121 C

(min)

HARDNESS

0.25 19.5 71

0.5 24.5

71

CO-AGENT 3 PTS

SULFENAMIDE LEVEL SCORCH TIME AT 121 C

(min)

HARDNESS

0

14

73

0.25 19 70

0.5 19 72

30

When

comparing

the results with those of

Example

2,

it is

generally recognized

that the standard

methacrylate grades

give superior physical properties as

evidenced

by

the

high

hardness values relative

to

the TAC cured

product.

The

methacrylate grades

suffer

primarily

from the scorch

problem.

The additions of the sulfenamide

to

the

polymethacrylate

formulation resulted in

higher Mooney

scorch times.

Also,

these results show

generally longer

levels of scorch time

35

than those obtained with

hydroquinone

alone,

indicating

that both

components

are required

in order

to

confer with

desired

activity.

EXAMPLE

4

(comparative)

40

Comparison

of

Hydroquinone

to

Other

Polymerizaton

Inhibitors

The

procedure

of

Example

1

was repeated

but

using a

different masterbatch formulation

as

follows:

Nitrile Rubber BR 1042 100

pts.

Zinc Oxide

5

pts.

Stearic Acid

1

pt.

FEF Carbon Black 40 pts.

Dicumyl peroxide

4

pts.


15

pts.

Various

potential

scorch additives

were

added

at

a

level of

5%

W/W relative

to

the

acrylate monomer.

Table

4 sets

forth the

test

results:

55

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TABLE

4

Scorch Retardant Additive

Mooney

Scorch

at

121 C Mins. Hardness* IRHD

None 8.33 84

Hydroquinone

60 46

Antioxidant 2246 10.06 79

Phenyl B-naphthylamine 8.48 83

Santowhite

Crystals

11.14

84

This demonstrates that

hydroquinone

is

unique

in its

ability

to

extend scorch

time,

but that it does

so

at

a

very

unacceptable

reduction of hardness when used alone

at

higher

levels.

After 60 mins

cure

at

160C.

Antioxidant 2246 is

2,2-methylene

bis

4,methyl,6-t-butyl phenol.

Santowhite

Crystals

is

a

Monsanto

product.

15

EXAMPLE

5

Diethyleneglycol dimethacrylate Comparison

with

Triallylcyanurate

Low Level

Polyunsaturated

Monomer in Cure

20

The

procedure

of

Example

1

was repeated

except

for the

use

of

a

different masterbatch formulation. One

co-agent

composition was prepared consisting

of

diethylene glycol dimethacrylate (83.3%), hydroquinone (1 .7%)

and

N-t-butyl-

benzthiazylsulfenamide (15%).

That formulation

was compared

with

an

identical masterbatch formulation in which TAC

was

substituted for the

diethylene glycol dimethylacrylate

and without the addition of scorch additives. Table

5 sets

forth the

test

results.

25

Ingredients

Parts

(by wt)

Vistalon 7500 EPDM 100

N550 Black 100

Paraffinic Oil

45

Antioxidant

TMQ 1

Coagent

Monomer 2

Vulcup

40KE

peroxide

5

35

TABLE

5

Coagent

Monomer 2 Parts

DIMETHACRYLATE TAC

Scorch Time

at

121 C

(min)

53

45

Hardness

57

60

Compression

Set

%

(22

hr

at 1

60C)

23.6 34.2

Elongation

at

break

%

360 31

5

Tensile

Strength

(MN.m-2)

14.5 15.7

The results show that the

dimethacrylate

cured

system

had

improved

scorch

time,

compression

set

and

elongation

compared to TAC. Hardness was slightly reduced and tensile strengths were approximately equivalent.

so

EXAMPLE 6

Low Level

Trimethylolpropane trimethacrylate-

TAC

The

procedure

of

Example

5

was repeated

except

only

30

pts

of

paraffinic

oil,

and

a

coagent

consisting

of trimeth-

55

ylolpropane trimethacrylate (83.55), N-t-butylbenzothiazolesulfenamide (15)

and

hydroquinone (1.45),

parts

were

used. Table 6

sets

forth the

test

results.

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TABLE 6

Coagent

2 Parts

METHACRYLATE TAC

Scorch Time

at

121 C 24.5 22.5

Hardness 70 67

Compression Set % (22 hrs at 160C) 21.9 16.2

Elongation

at

break

%

255 235

Tensile

Strength

(MN.m-2)

17.6 17.9

The results show that

even

at

low levels of

polyacrylate

addition in the form of

diacrylate

and

triacrylate

the scorch

retardant effect of the scorch retardant mixture

was

about

equivalent

to

TAC and

yet

hardness

was

better and

com-

pression

set

somewhat

poorer.

EXAMPLE

7

High

Level of Process Oil Addition

The

procedure

of

Example

6

was repeated

except

at

higher

levels of

process

oil addition. The

system

was com-

pared

to

TAC

systems.

Using

the

Example

6


co-agent

composition

in

a

rubber

com-

pound as

above

containing

65

parts

of

paraffinic

process

oil,

data

are as

follows in Table

7.

TABLE

7

Coagent

2

parts

METHACRYLATE TAC

Scorch Time

77

>120

Hardness 49

44

Compression

Set

%

(22

hrs

at

160C)

27.0 65.1

Elongation

at

break

%

480

515

Tensile

Strength

(MN.m"2)

12.0 6.9

The

advantage

of the scorch

retarding polyacrylate

systems

over

TAC

systems

is best

emphasized

at

the

highest

loading

levels of

process

oil. Hardness

was

better and tensile

strength was nearly

double.

Compression

set

was con-

siderably improved

in the

methacrylate

system.

EXAMPLE 8

(comparative)

Scorch Retardation

System

in the Absence of

Hydroquinone

The

procedure

of

Example

1

was repeated

except

hydroquinone was

omitted from the scorch

retarding polyacrylate

system.

The sulfenamide derivative failed

to

give adequate

scorch

protection.

The formulation consisted of:

Parts

(by wt)

Breon N3670 Nitrile Rubber 100

FEF Carbon Black 40

Zinc Oxide

5

Stearic Acid

1

DiCup

40C

(peroxide)

5


15

N-t-butylbenzothiazolesulfenamide

2

A

Mooney

Scorch of

only

6 1/2 minutes and

a

vulcanisate hardness of 81

was

obtained thus

showing

the need for

the scorch

retarding

additive,

hydroquinone,

in combination with the sulfenamide.

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EXAMPLE 9

(comparative)

Vulcanization without Scorch Retardant Effect of

Acrylate Functionality

The

procedure

of

Example

1

was repeated

except

that the

following

masterbatch

was

used. No

special

addition

of scorch-retardant

agent(s) was

made. The results

are

in Table 8.

NBR B36C70 Nitrile Rubber 100

FEF Black 40

Zinc Oxide

5

Stearic Acid

1

Antioxidant

TMQ

0.5

DiCup

40C

(peroxide)

7

Polyacrylate

Monomer

(See

Table 8

)

15

TABLE 8

MONOMER FUNCTIONALITY SCORCH TIME AT 121 C

(min)

IRHD HARDNESS

TETRAHYDROFURFURYL

1

24 63

METHACRYLATE

1,3-BUTANEDIOL

2 9 81

DIMETHACRYLATE

TRIMETHYLOLPROPANE 3

7

84

TRIMETHACRYLATE

These results show that


without

a

scorch

retarding

agent

scorch times

were

low. The

monounsaturated

monomer

had better scorch time but

at

the

expense

of hardness. The

appearance

of the

products

showed

severe scorching. Scorching

became

more

severe,

as expected,

with

increasing functionality

of the

polyacr-

ylate

and such scorch times

were significantly

lower for the

higher

functional

polyfunctional(meth)acrylates.

However,

the


cured elastomers had better and excellent hardness.

EXAMPLE 10

(comparative)

Effect of

Hydroquinone

on

Vulcanization

-

No Sulfenamide

The

procedure

of

Example

1

was repeated

except

that the

percentage

of

hydroquinone was

varied based

on

the

trimethylolpropane methylacrylate.

No sulfenamide

was

used. The results

are

set

forth in Table 9.

Table 9

%

ADDITION OF

HYDROQUINONE

ON MONOMER SCORCH TIME AT 121 C

(min)

IRHD HARDNESS

0

7.5

84

0.5 16 82

1

.0 25 76

3.0 58 60

5.0 >60 50

The

increasing

levels of

hydroquinone

based

on

the

weight

of the

polyf unctional(meth)acrylate

extended the scorch

time with

increasing hydroquinone

levels,

but reduced the vulcanisate hardness. These results in

terms

of vulcanisate

hardness

are

is consistent with

Example

1

,

and

they

also show the

importance

of sulfenamide addition.

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EXAMPLE

11

(comparative)

Scorch Retardant

Using Tetramethyl/Thiuram

Monosulfide

The

procedure

of

Example

1

was repeated,

but

using tetramethyl

thiuram monosulfide in

place

of the sulfenamide.

The results obtained

are

set

forth in Table 10.

Monosulfide Hydroquinone Scorch Time 121 C Hardness

1 1

27.4 73

0.5

1

30.1 73.5

1

0.5 21.5

77

0.5 0.5 21.2 78

This demonstrates that the Monosulfide

system

has

an interesting

combination of

properties,

but that its

perform-

ance

is

not

as

the

preferred

sulfenamide

system.

EXAMPLE 12

(comparative)

Commercial Scorch Retardant and Effect

Two commercial scorch retardant

systems

were compared

to

the formulation of

Example

1

in order

to

provide

comparative performance requirements.

The formulation

was as

follows:

NBR N36C70 Nitrile Rubber 100

FEF Black N550 40

Zinc Oxide

5

Stearic Acid

1

Monomer

15

Vulcup

40KE

peroxide

4

TABLE 8

MONOMER SCORCHTIME

AT121C(min)

IRHD HARDNESS

EXAMPLE

1

43.5 85

TRIMETHYLOLPROPANE TRIMETHACRYLATE 6 1/2 84

COMMERCIAL PRODUCT

1 47.5

83

COMMERCIAL PRODUCT 2 40.5 83

The results show similar scorch times and hardness for the scorch retardant

systems

described herein

to

estab-

lished commercial

systems.

EXAMPLE 13

(comparative)

Effect of

N-Cyclohexylbenzothiazolesulfenamide

The

procedure

of

Example

4

was repeated using

the

same

masterbatch,

but

using N-cyclohexyl

benzothia-

zolesulfenamide

at

a

level of

5%

relative

to

the

methacrylate monomer.

This formulation

gave

a

scorch-time of 9.5

minutes

at

121C and

a

vulcanisate hardness of 83 after

cure

for 60 mins

at

160C. This further demonstrates that

sulfenamide

by

itself will

not

render the scorch

properties adequate.

EXAMPLE

14

Effect of

N-Cyclohexylbenzothiazolesulfenamide

The

procedure

of

Example

1

was repeated

except

that the

t-butyl-sulfenamide was replaced by N-cyclohexylben-

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zothiazolesulfenamide

at

a

level of

3%

relative

to

the

methacrylate monomer.

However,

the combination

was only

slightly

inferior

to

the commercial

products

of

Example

11

.

Claims

1

.

Scorch

retarding polyunsaturated monomer containing

system

suited for

curing peroxide

curable elastomers and

polyethylene, polypropylene, copolymers containing ethylene units and copolymers containing propylene units,

which

comprises polyunsaturated

monomer,

0.2

to

6

weight

percent

hydroquinone

based

upon

said

polyunsatu-

rated

monomer

and

1 to

50

weight

percent

sulfenamide based

upon

said

polyunsaturated monomer.

2. The scorch retardant

system

of Claim

1

wherein the sulfenamide is

represented by

the formulas

:

I

and

wherein

:

R is

up

to

C10;

R1

is

H,

C|_10

aliphatic, aryl, cycloalkyl or aralkyl

;

R2

is

C|_10


combined with

R1


group

;

and

X is


C-,.6

alkyl,

C-,.6

alkoxy.


system

of Claim 2 wherein the


is selected from the

group

of

poly-

functional

(meth)acrylates

and

polyallylic monomers.


system



is

a polyacrylic or methacrylic

ester

of

a

C2_-2

polyol.


system

of Claim

4

wherein the

polyol

is

C2.8

diol

or

triol.


system

of Claim

5

wherein said sulfenamide is selected from the

group

consisting

of

N,N-

dicyclohexylbenzothiazolesulfenamide

;

N,N-diisopropyl-2-benzothiazolesulfenamide

;

2-(4-morpholino)thioben-

zo-thiazole

(MTB)

;

N-t-butyl-2-benzothiazolesulfenamide

;

and

N-cyclohexyl-2-benzothiazolesulfenamide.


system

of Claim

1

intended

to

be used in

a peroxide

curable elastomer selected from the

group

consisting

of

polyisoprene, styrene-butadiene

rubbers,

polybutadiene,

neoprene,

butyl,

chlorinated

polyeth-

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ylene, ethylene-propylene,

and


rubbers,

and silicone

elastomers,

or

in

a peroxide

curable

ethylene

-

vinylacetate copolymer.


system

of Claim

7

wherein the

weight

parts

hydroquinone

per

1

00

weight

parts

polyfunctional

(meth)acrylate are

from 0.5

to 5.


system

of Claim 8 wherein the sulfenamide is

present

in

an

amount

from 2

to

20

parts

per

100 parts by weight polyfunctional (meth)acrylate.


system


N-t-butylbenzothiazolesulfenamide.

11. Acurable

composition comprising an

elastomer

or polyethylene or polypropylene or a copolymer containing

eth-

ylene

units

or a copolymer containing propylene

units

having an

abstractable

hydrogen

atom

crosslinkable with

a

polyfunctional (meth) acrylate, polyfunctional (meth) acrylate, organic peroxide,

and

a

scorch

retarding

additive

which

comprises

from 0.2

to 6%

by weight

of

hydroquinone

based

upon

said


and

from

1 to 50%

by weight

of

a

sulfenamide based

upon

said

polyfunctional (meth)acrylate.

12. The curable

composition

of Claim

11

wherein the sulfenamide is

represented by

the formulas

:

I

and

X

wherein

:

R is

up

to

C10;

R1

is

H,

C|_10

aliphatic, aryl, cycloalkyl or aralkyl

;

R2

is

C|_10


combined with

R1


group

;

and,

X is


C-,.6

alkyl,

C-,.6

alkoxy.

13. The

composition


represented by

formula

1

and

R-,

is

hydrogen

and

R2

is

aliphatic.

14. The curable

composition



is

a polyacrylic or methacrylic

ester

of

a

C2.12

polyol.

15. The curable

composition

of Claim

14

wherein the

polyol

is

C2.8

diol ortriol.

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20

1.

25

2.

30

35

40

45

50

55

3.

i.

The curable

composition

of Claim

15

wherein said sulfenamide is selected from the

group

consisting

of

N,N-

dicyclohexylbenzothiazolesulfenamide

;


;

2-(4-morpholino)thioben-

zo-thiazole

(MTB)

;

N-t-butyl-2-benzothiazolesulfenamide;

and

N-cyclohexyl-2-benzothiazole-sulfenamide.

'. The curable

composition

of Claim

1

6 wherein the elastomer is selected from the

group

consisting

of

polyisoprene,

styrene-butadiene

rubbers,

polybutadiene,

neoprene,

butyl,

chlorinated

polyethylene ethylenepropylene,

and buta-

diene-acrylonitrile

rubbers,

and silicone

elastomers,

or

wherein the

copolymer containing ethylene

units is

ethylene

- vinyl acetate copolymer.

The curable

composition

of Claim

17

wherein the

weight

parts

hydroquinone

per

100

parts


acrylate are

from 0.5

to 5.

i.

The curable

composition


present

in

an

amount

from 2

to

20

parts

per

100

weight

parts

polyfunctional (meth)acrylate.

i.

The curable

composition


N-t-butylbenzothiazolesulfenamide.

Mehrfach ungesattigtes Monomer enthaltendes Scorchschutzsystem fur die Hartung von peroxidhartbaren Ela-

stomeren

und

Polyethylen, Polypropylen,- Ethyleneinheiten

enthaltenden

Copolymeren

und

Propylen

enthalten-

den

Copolymeren,

enthaltend mehrfach

ungesattigtes

Monomer, 0,2

bis 6

Gewichtsprozent Hydrochinon, bezogen

auf das mehrfach

ungesattigte

Monomer,

und

1

bis 50

Gewichtsprozent

Sulfenamid,

bezogen

auf das mehrfach

ungesattigte

Monomer.

Scorchschutzsystem

nach

Anspruch

1,

wobei das Sulfenamid durch die Formeln:

dargestellt

wird,

worin:

R fur bis

zu

C10

steht;

R-,

fur

H,

C-|.10-Aliphat,

-Aryl, -Cycloalkyl

oder

-Aralkyl

steht;

RgfiirC-i.-io-Aliphat,

-Aryl, -Cycloalkyl

oder

-Aralkyl

steht oder

gemeinsam

mit

R1

eine

heterocyclische Gruppe

bildet;

und

Xfur

Wasserstoff,

Halogen, Hydroxy,

C-|.6-Alkyloder C-|.6-Alkoxy

steht.

Scorchschutzsystem

nach

Anspruch

2,

wobei das mehrfach

ungesattigte

Monomer

aus

der

Gruppe

der

polyfunk-

tionellen

(Meth)acrylate

und

Polyallylmonomere

stammt.

Patentanspriiche

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EP 0 569 995 B1

Scorchschutzsystem

nach

Anspruch

3,

wobei

es

sich bei dem mehrfach

ungesattigten

Monomer

urn

einen

Poly-

acryl-

oder

Methacrylsaureester

eines

C2_12-Polyols

handelt.

Scorchschutzsystem

nach

Anspruch

4,

wobei

es

sich bei dem

Polyol urn

ein

C2.8-Diol

oder -Triol handelt.

Scorchschutzsystems

nach

Anspruch

5,

wobei das Sulfenamid

aus

der

Gruppe

bestehend

aus N,N-Dicyclohexyl-

benzothiazolsulfenamid;

N,N-Diisopropyl-2-benzothiazol-sulfenamid; 2-(4-Morpholino)

thiobenzothiazol

(MTB);

N-t-Butyl-2-benzothiazolsulfenamid und N-Cyclohexyl-2-benzothiazolsulfenamid stammt.

Scorchschutzsystem

nach

Anspruch

1

zur Verwendung

in einem

peroxidhartbaren

Elastomer

aus

der

Gruppe

bestehend

aus Polyisopren, Styrol-Butadien-Kautschuken, Polybutadien-, Neopren-, Butyl-, Chlorpolyethylen-,

Ethylen-Propylen-

und

Butadien-Acrylnitril-Kautschuken

sowie Silicon-Elastomeren oder in einem

peroxidhartba-

ren Ethylen-vinylacetat-copolymer.

Scorchschutzsystem

nach

Anspruch

7,

worin

Hydrochinon

in einer

Menge von

0,5

bis

5

Gewichtsteilen

pro

100

Gewichtsteile

polyfunktionelles (Meth)acrylat vorliegt.

Scorchschutzsystem

nach

Anspruch

8,

worin das Sulfenamid in einer

Menge von

2 bis 20 Gewichtsteilen

pro

100

Gewichtsteile


Scorchschutzsystem nach Anspruch 9, wobei es sich bei dem Sulfenamid urn N-t-Butylbenzothiazolsulfenamid

handelt.

Hartbare

Zusammensetzung

mit einem Elastomer oder

Polyethylen

oder

Polypropylen

oder einem

Ethyleneinhei-

ten

enthaltenden

Copolymer

oder einem

Propyleneinheiten

enthaltenden

Copolymer,

das ein abstrahierbares

Wasserstoffatom

aufweist,

das mit einem

polyfunktionellen (Meth)acrylat

vernetzbar

ist,

polyfunktionellem (Meth)-

acrylat,

organ

ischem Peroxid und einem

Scorchschutz-additiv,

enthaltend

0,2

bis 6

Gew.-%

Hydrochinon, bezogen

auf das

polyfunktionelle (Meth)acrylat,

und

1

bis 50

Gewichtsprozent

Sulfenamid,

bezogen

auf das

polyfunktionelle

(Meth)acrylat.

Hartbare

Zusammensetzung

nach

Anspruch

11,

wobei das Sulfenamid durch die Formeln:

I

und

dargestellt

wird,

worin:

R fur bis

zu

C10

steht;

R-,

fur

H,

C-|.10-Aliphat,

-Aryl, -Cycloalkyl

oder

-Aralkyl

steht;

R2furC-|_10-Aliphat,

-Aryl, -Cycloalkyl

oder

-Aralkyl

steht oder

gemeinsam

mit

R-,

eine

heterocyclische Gruppe

bildet;

und

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EP 0 569 995 B1

Xfur

Wasserstoff,

Halogen, Hydroxy,

C-|.6-Alkyloder C-|.6-Alkoxy

steht.

13.

Zusammensetzung

nach

Anspruch

12,

wobei das Sulfenamid die Formel Iaufweist und

R-,

fur Wasserstoff steht

und

R2

aliphatisch

ist.

14. Hartbare

Zusammensetzung

nach

Anspruch

13,

wobei

es

sich bei dem

polyfunktionellen (Meth)acrylat urn

einen

Polyacryl-

oder

Methacrylsaureester

eines

C2_12-Polyols

handelt.

15. Hartbare

Zusammensetzung

nach

Anspruch

1

4,

wobei

es

sich bei dem

Polyol urn

ein

C2_8-Diol

oder -Triol handelt.

16. Hartbare

Zusammensetzung

nach

Anspruch

15,

wobei das Sulfenamid

aus

der

Gruppe

bestehend

aus

N,N-

Dicyclohexylbenzothiazolsulfenamid; N,N-Diisopropyl-2-benzothiazolsulfenamid;

2-

(4-Morpholino)

thiobenzot-

hiazol

(MTB); N-t-Butyl-2-benzothiazolsulfenamid

und

N-Cyclohexyl-2-benzothiazolsulfenamid

stammt.

17. Hartbare

Zusammensetzung

nach

Anspruch

16,

wobei das -Elastomer

aus

der

Gruppe

bestehend

aus Polyisopren,

Styrol-Butadien-Kautschuken, Polybutadien-, Neopren-, Butyl-, Chlorpolyethylen-, Ethylen-Propylen-

und Butadi-

en-Acrylnitril-Kautschuken

sowie Silicon-Elastomeren

stammt

oder

es

sich bei dem

Ethyleneinheiten

enthaltenden

Copolymer urn Ethylen-vinylacetat-copolymer

handelt.

18. Hartbare

Zusammensetzung

nach

Anspruch

17,

worin

Hydrochinon

in einer

Menge von

0,5

bis

5

Gewichtsteilen

pro 100 Gewichtsteile polyfunktionelles (Meth)acrylat vorliegt.

19. Hartbare

Zusammensetzung

nach

Anspruch

18,

worin das Sulfenamid in einer

Menge von

2 bis 20 Gewichtsteilen

pro

100 Gewichtsteile


20. Hartbare

Zusammensetzung

nach

Anspruch

19,

wobei

es

sich bei dem Sulfenamid

urn N-t-Butylbenzothiazolsul-

fenamid handelt.

Revendications

1.

Systeme anti-grilleur

contenant

un monomere polyinsature, approprie

pour

durcir des elastomeres durcissables

par

un peroxyde

et

le

polyethylene,

le

polypropylene,

des

copolymeres

renfermant des motifs

ethylene

et

des

copolymeres


propylene, qui comprend un monomere polyinsature,

de

0,2 a

6

pour cent en

poids d'hydroquinone,

par

rapport

audit

monomere polyinsature,

et

de

1

a

50

pour

cent

en poids

de

sulfenamide,

par

rapport

audit

monomere polyinsature.

2.


selon la revendication

1

,

dans

lequel

le sulfenamide

est

represents

par

les formules

:

I

et

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I I

5

10

dans

lesquelles :

R

est

jusqu'en

C10

;

R-i

est

H,

un aliphatique, un aryle, un cycloalkyle ou un aralkyle en

C-|.10

;

is

-

R2

est

un aliphatique, un aryle, un cycloalkyle ou un aralkyle en

C-|.10,

ou

combine

avec

R-,

en

formant

un

groupe

heterocyclique

;

et

X

est

un hydrogene, un halogene, un hydroxy, un alkyle en

C g,

un alcoxy en

C^g.

3.



2,

dans

lequel

le

monomere polyinsature

est

choisi

parmi

le

groupe

20

de

(meth)acrylates polyfonctionnels

et

de

monomeres polyallyliques.

4.



3,

dans

lequel

le

monomere polyinsature

est

un

ester

polyacrylique

ou methacrylique

d'un

polyol en

C2_12.

25

5.



4,

dans

lequel

le

polyol

est

un

diol

ou

triol

en

C2.8.

6.



5,

dans

lequel

ledit sulfenamide

est

choisi

parmi

le

groupe

constitue

du

N,N-dicyclohexylbenzothiazolesulfenamide

;

du


;

du

2-(4-mor-

pholino)thiobenzothiazole (MTB)

;

du

N-t-butyl-2-benzothiazolesulfenamide

;

etdu

N-cyclohexyl-2-benzothiazole-

30

sulfenamide.

7.



1,

destine

a

etre

utilise dans

un

elastomere durcissable

par

un

pe-

roxyde,

choisi

parmi

le

groupe

constitue d'un

polyisoprene,

de caoutchoucs

styrene-butadiene,

d'un

polybutadiene,

d'un

neoprene,

d'un

butyle,

d'un

polyethylene chlore,

de caoutchoucs

ethylene-propylene et butadiene-acryloni-

35

trile,

et

d'elastomeres

a

la

silicone,

ou

dans

un copolymere ethylene-acetate

de

vinyle

durcissable

par

un peroxyde.

8.



7,

dans

lequel

les

parties en poids d'hydroquinone

pour

100

parties

en poids

de

(meth)acrylate polyfonctionnel

sont

de

0,5

a

5.

40

9.



8,

dans

lequel

le sulfenamide

est

present

en une quantite

allant de 2

a

20

parties

pour

100

parties en poids

de

(meth)acrylate polyfonctionnel.

10.



9,

dans

lequel

le sulfenamide

est

le

N-t-butylbenzothiazolesulfenami-

de.

45

11.

Composition

durcissable

comprenant

un

elastomere,

ou

du

polyethylene,

du

polypropylene, un copolymere ren-

fermant des motifs

ethylene ou un copolymere


propylene,

ayant

un

atome

d'hydrogene

pouvant

etre

elimine,

et

reticulable

avec un (meth)acrylate polyfonctionnel, un peroxyde organique

et

un

additif

anti-grilleur,

et

qui comprend

de

0,2

a

6%

en poids d'hydroquinone,

par

rapport

audit

(meth)acrylate polyfonctionnel,

so

et

de

1

a

50%

en poids

d'un sulfenamide

par

rapport

audit

(meth)acrylate polyfonctionnel.

12.

Composition

durcissable selon la revendication

11,

dans

laquelle

le sulfenamide

est

represents

par

lesformules

:

55

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Documents

Transcript of EP0569995B1