JP2003514088A - Tack-free surface curing of polymers with organic peroxides in the presence of air - Google Patents

Abstract

  (57) [Summary] When formulated into a polymer curable by a free radical initiator in the presence of a free radical initiator, a substantially tack free surface cure of the polymer is achieved by decomposing the free radical initiator in the presence of molecular oxygen. At least one compound selected from silicone elastomers, bis-, tri- or higher polymaleimides and / or bis-, tri- or higher citraconimides, and p-phenylenediamine-based Disclosed is a composition comprising a mixture of at least one compound selected from an antiozonant, a sulfur compound and a sulfur compound capable of promoting sulfur vulcanization of a polymer that can be crosslinked by sulfur and a polysulfide polymer. Also disclosed are compositions containing the above components and at least one free radical initiator, curable compositions containing the compositions, and processes for making and using the compositions.

Description

Detailed Description of the Invention

TECHNICAL FIELD In the field of chemistry, the present invention relates to bis-, tri- and higher polymaleimides, bis-, tri- and higher citraconic imides, and silicone elastomers. Classified as p-phenylenediamine-based antiozonants and as sulfur-containing organic compounds that are sulfur and accelerators for sulfur-curing (crosslinking) polymers curable / crosslinkable by sulfur compounds that are also polysulfide polymers Substance composition. The invention also relates to compositions containing them, processes of using them and products produced by such processes.

Polymers and copolymers crosslinked by free-radical initiators, organic peroxides and / or azo initiators are known to have excellent properties, especially compared to polymers crosslinked by sulfur curing. There is. These properties include high heat aging resistance, low compression set, reduced contamination of metal or coated metal sheets and ease of manufacture of colored products with color stability during crosslinking and long term use. . These properties make very important peroxide curing very important, especially since the cross-links are through carbon-carbon bonds rather than through sulfur-containing bonds and the bond differences lead to heat aging and improved compression set. To use. The disadvantages of curing polymers by free radicals from organic peroxides and azo initiators are always the stickiness of the curing due to molecular oxygen in the air, if air is removed from the surface of the material during curing. It was that there was sex.

In order to avoid stickiness on objects processed using free radical cross-linking with such organic peroxides and / or azo initiators, caused by the presence of molecular oxygen found in atmospheric air. It was customary to avoid contacting the surface with air during curing in order to avoid the cure inhibition that occurs. Means for removing molecular oxygen add to the cost and complexity of the curing process, and sometimes, as in the case of curing in a steam autoclave or inside a hose, complete evacuation of air and its molecular oxygen components. Is difficult to secure. There are some cases where a manufacturer may want to switch from sulfur to peroxide curing and use a hot air oven curing chamber. Curing with conventional peroxide systems under these circumstances would not be feasible as it would result in a tacky surface.

In order to simplify and reduce the cost and complexity of the curing process, various methods have been proposed to prevent surface cure inhibition by molecular oxygen during free radical crosslinking. These methods have had little or no success in actual practice for a variety of reasons. In particular, the most desirable physical properties of peroxide (azo) curing;
About 100 ° C, or 150 compared to the lower temperature performance for the prior art
None provided a tack-free surface while providing excellent compression set at 70 ° C. for 70 hours.

Prior Art US Pat. No. 4,983,685 discloses the use of compounds selected from the following classes: (a) imidazole compounds, (b) thiourea compounds, (c). Thiazole compounds, (d) thiuram compounds, (e) dithiocarbamate compounds, (f) phenol compounds, (g) triazole compounds and (h) amine compounds, which are optional antioxidants, aging-resistant compounds, etc. In the presence of
It is an accelerator for sulfur vulcanization for elastomers to reduce tackiness when peroxide curing an elastomer in the presence of molecular oxygen. Among the optional ingredients proposed as possible ingredients for inclusion in the formulation is N, N'-m-phenylene bismaleimide, in this case for increased crosslinking.

This is not a preferred optional co-drug, since dimethacrylate compounds are actually used in the examples. This latter bismaleimide compound would have an enhanced effect on the ability of certain compounds (a)-(h) to reduce tack during free radical curing in the presence of molecular oxygen. There is no recognition to say. The use of various sulfur promoters, especially with peroxides, results in this document in the absence of tacky or reduced tacky surfaces for the cured polymer, but also the important physical properties expected from peroxide curing. It is also reduced. U.S. Pat. No. 4,983,685 discloses silicone elastomers of the invention, biscitraconimide and biscitraconimide, in the free radical cure of polymers, p-phenylenediamine based antiozonants, sulfur-containing sulfur vulcanizates. If used in combination with accelerators and antioxidants and / or polysulphide polymers, a tack-free surface and improved physical properties will result and, among all the above mentioned co-agents, There is no recognition that only these particular classes of compounds have that effect.

Japanese Unexamined Patent Publication No. 9 [1997] -169873 discloses antioxidants of benzimidazole type and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline type, methacrylate ester, triallyl cyanurate and When used in combination with standard crosslinking aids such as maleimides such as N, N'-m-phenylene bismaleimide, a preferred component of the invention, as well as standard crosslinking peroxides,
It is disclosed that the presence of air will result in a cured peroxide crosslinkable elastomer having a tack free surface. The inclusion of p-phenylenediamine based antiozonants, silicone elastomers, sulfur accelerators of any type and / or polysulfide polymers is not suggested.

US Pat. No. 4,334,043 discloses that a curable polymer composition is crosslinked with an organic peroxide crosslinking initiator in air to prevent stickiness after crosslinking.
It teaches the use of surface treatments with organo metal compounds, inorganic metal salts, or lanthanides. No other means of controlling tack is mentioned other than the previously known technique of curing in the absence of tack by simply removing air contacting the rubber surface.

US Pat. Nos. 4,814,384 and 4,973,627 disclose the cure of rubber blends for tire treads and sidewalls using a combination of sulfur cure and peroxide cure. . Sulfur accelerators have also been used. No mention is made of any type of co-drug, nor is cure in the presence of air. The practice of these inventions requires the use of elemental sulfur. However, the inventors have found that the use of elemental sulfur adversely affects the ultimate physical properties of the cured elastomer, to the point that it more symbolizes sulfur cure than peroxide cure.

US Pat. No. 4,743,656 also discloses mixed sulfur / peroxide curatives for elastomers, which also include sulfur promoters and elemental sulfur and peroxides. No mention is made of co-drugs, nor is cross-linking and tackiness in air discussed.

US Pat. No. 4,575,552 discloses hindered phenol antioxidants, dithiocarbamates and dithiocarbamates to impart excellent hydrolytic and thermal stability to peroxide crosslinked polymers for geothermal applications. Claims to use specific combinations of metal salts of m-phenylenedimaleimide. No mention is made of crosslinking in the presence of air, air suppression or tackiness as a result of air suppression.

US Pat. No. 5,849,214 discloses that a sulfur compound, a sulfur promoter and a hydroquinone can be used as a crosslinking aid in suppressing burns during compounding of a free radical crosslinkable polymer in the presence of a free radical initiator. The use with an optional presence of an agent (co-drug) is disclosed. Bismaleimides and biscitraconimides have not been specifically investigated, nor has any of the disclosed compositions been described for their possible effect on tack during curing in the presence of molecular oxygen.

In addition, there are several patents that use various compounds to physically coat the surface of crosslinkable elastomers to remove air (oxygen), eg US Pat. No. 4,439,
No. 388 teaches the use of boric acid, boric anhydride as a surface treatment followed by hot air curing. This surface coating technique is labor intensive as the coating must be removed and disposed of after the crosslinking reaction step is completed.

Whether the above documents are adopted alone or in combination, the peroxide (
Azo) curing while providing desirable physical properties, such as compression set values expected from standard peroxide curing, where compression set is measured in the region of about 150 ° C. for 70 hours. Applicants' solution described herein and claimed that eliminates surface tack by air suppression during free radical curing of a polymer by a free radical curing agent such as an azo initiator. Do not suggest.

DISCLOSURE OF THE INVENTION The invention is, in a first composition aspect, a composition comprising: a) at least one compound (A) selected from the group consisting of a silicone elastomer and a compound having formula (I): ):

[Chemical 2] Wherein n is 1 or 2, R is divalent or trivalent and has about 2 to 16 carbon atoms.
A group having an acyclic aliphatic group having 5 to 20 carbon atoms, a cycloaliphatic group having from about 5 to 20 carbon atoms, an aromatic group having from about 6 to 18 carbon atoms and an alkyl aromatic group having from about 7 to 24 carbon atoms. And those divalent or trivalent groups may contain one or more heteroatoms selected from O, N and S instead of one carbon atom or a plurality of carbon atoms, each R ₁ are the same and are hydrogen or an alkyl group of 1 to 18 carbon atoms: and b) promote sulfur crosslinking of p-phenylenediamine based antiozonants and polymers that can be crosslinked by sulfur. At least one compound selected from the group consisting of sulfur-containing organic compounds (“sulfur promoters”), polysulfide polymers and mixtures of said sulfur-containing compounds which are capable of To provide an object (B).

A substantive embodiment of the first composition aspect of the invention is a suppressor of surface inhibition of polymer free-radical induced curing in the presence of gaseous molecular oxygen (ie, oxygen present in the atmosphere). The absence of polymer stickiness by the free radical curing agent in the presence of air, while having the inherent applied use of exhibiting the property of being, thereby preserving the final physical properties associated with conventional peroxide curing. Allows curing.

The invention, in a subgenus aspect of the first composition aspect of the invention, comprises at least one member of compound (A) and at least one member of compound (B) of the first composition aspect of the invention. To provide a composition formed by mixing

The invention provides in a second composition aspect a composition comprising a composition as defined in the first composition aspect and a free radical initiator selected from the group consisting of organic peroxides and azo initiators. .

A substantive embodiment of the second composition aspect of the invention is that the polymer to be cured is air (
It can be crosslinked by free radical initiators and undergo such curing in the presence of air (molecular oxygen) without undergoing surface inhibition by the presence of (molecular oxygen) and thereby cure. Curing agents or crosslinks for those polymers that provide a cured or crosslinked polymer having a substantially tack-free surface without requiring contact of the surface with air (molecular oxygen) It has a unique applied use that characterizes that it is a drug.

The invention provides a subgenus aspect of the second composition aspect of the invention. The composition comprises at least one member of compound (A) and compound (B) of the first composition aspect of the invention.
And a free radical initiator as defined for the second composition aspect of the invention, in any order.

The invention provides a curable composition comprising, in a third composition aspect, a polymer curable by a free radical initiator and a composition as defined for the second composition aspect of the invention.

The third composition aspect of the invention can be formed into a shaped article, which is then crosslinked while contacting the surface of the shaped article with air (molecular oxygen) to yield a substantially tacky article. It has unique applied uses that characterize that it can be a crosslinked shaped article with a non-existent surface.

The invention provides, in a substantive embodiment of the third composition aspect of the invention, at least one member of compound (A) and at least one member of compound (B) of the first composition aspect of the invention. And a free radical initiator as defined for the second composition aspect of the invention and a polymer crosslinkable by the free radical initiator in any order. To do.

The invention comprises, in a first process aspect, at least one member of compound (A) and at least one member of compound (B) of the first composition aspect of the invention, and a second composition of the invention. Provided is a process for preparing a second composition aspect of the invention, comprising mixing a free radical initiator as defined in the aspect in any order.

The invention provides, in a second process aspect of the invention, a compound of the first composition aspect of the invention (
Optionally at least one member of A) and at least one member of compound (B), a free radical initiator as defined in the second composition aspect of the invention, and a polymer crosslinkable by the free radical initiator. Providing a process for preparing a third composition aspect of the invention comprising mixing in the order of.

Compound (A), compound (A) selected from bismaleimide and compound (B) selected from sulfur promoter, compound (A) selected from biscitraconimide and compound (B) selected from sulfur promoter From the bismaleimide and the compound (B) from the polysulfide polymer, the compound (A) from the biscitracone imide and the compound (B) from the polysulfide polymer, the compound (A) from the silicone elastomer and the compound (B Particular mention is made of the embodiments of several aspects of the invention in which a) is selected from polysulfide polymers.

Also specifically mentioned are embodiments of several aspects of the invention in which, in addition to compound (A) and compound (B), chlorinated polyethylene and / or chlorosulfonated polyethylene is included as an optional supplemental component.

Description of the Preferred Embodiments The best mode for the inventors to make and use the invention will now be described in detail by means of a specific embodiment of the invention, namely: dipenta Methylene thiuram tetra-sulfide (Sulfads) and N, N
Ethylene using a mixture of'-m-phenylene bismaleimide (HVA-2) and 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane (LUPEROX® 231XL). Propylene copolymer (VI
STALON® 504) is cured in hot air.

To prepare a mixture of Sulfads, HVA-2, and LUPEROX 231XL, all of these ingredients were in dry powder form (LUPEROX 231
XL is a form in which 40% by weight of peroxide is dispersed on calcium carbonate)
May be mixed in any order and then compounded by standard methods (Banbury, twin rolls, extruders, etc.) into a VISTALON polymer. Also, Su
lfads®, HVA-2, and LUPEROX 231XL may be blended either directly or sequentially in any order to make VISTALON directly. Any two of the Sulfads, HVA-2 and LUPEROX 231XL components are mixed and the third component is blended separately or simultaneously and VISTALON
You can This formulation may be carried out separately or in any order of the components added to the polymer, but is preferred if the peroxide is added last.

Once the VISTALON compounding is complete, the compounded mixture is heated to a temperature suitable for initiating curing by decomposition of peroxide in a hot air oven, conveniently about 365 ° F. (about 185 ° F. in this case). C.) for a period sufficient to produce the desired degree of crosslinking,
Conveniently, in this case, the thin sample, initially at room temperature, may simply be cured by placing it for about 10 minutes.

Those skilled in the art will appreciate that other compounds falling within the scope of formula I of the first compositional aspect of the invention are all solid substances, all trimaleimides, bismaleimides, tricitraconic imides or biscitraconic imides. And all other starting materials contemplated by the invention can be combined by conventional methods similar to those described. The starting materials and the intended bismaleimides and biscitraconimides are either all commercially available or can be readily synthesized by methods well known in the art. For example, US Pat. Nos. 5,484,948; 5
, 616,666; 5,292,815 and the references cited herein for more general synthetic methods.

Trimaleimides and tricitraconimides and higher polymaleimides and citraconimides can be prepared by similar techniques if they are not commercially available. For example, trimaleimide N, N ', N "
-(1,3,5-triazine-2,4,6-tolyl) trimaleimide is CAS
It has the number CAS (67460-81-5).

Suitable primary amines for synthesizing di-, tri- and higher polymaleimides and similar citracone imides are polyfunctional primary amines such as melamine, polyoxypropylene diamines and poly Various polyoxypropylene amines such as oxypropylene triamine, Hunstsman Corpora
is sold under the trade name JEFFAMINE.

In addition to the N, N′-m-phenylene-bismaleimides specifically quoted above, other bismaleimides suitable for use in the invention without limiting the generality of the general formula (I) above are: In addition to those disclosed in the above cited patents are: N, N'-ethylene bismaleimide, N, N'-hexamethylene bismaleimide, N, N'-dodecamethylene-bismaleimide, N, N '-(2,2,4-trimethylhexamethylene) bismaleimide, N, N'-(oxy-dipropylene) bismaleimide, N, N '-(aminodipropylene) bismaleimide, N, N
'-(Ethylenedioxy-dipropylene) bismaleimide, N, N' (1,4-
Cyclohexylene) bismaleimide, N, N ′ (1,3-cyclohexylene) bismaleimide, N, N ′-(methylene 1,4-dicyclohexylene) bismaleimide, N, N ′-(isopropylidene 1,4) -Dicyclohexylene) bismaleimide, N, N '-(oxy-1,4-dicyclohexylene) bismaleimide, N
, N'-p- (phenylene) bismaleimide, N, N '-(o-phenylene) bismaleimide, N, N'-(1,3-naphthylene) bismaleimide, N, N'-
(1,4-naphthylene) bismaleimide, N, N ′-(1,5-naphthylenebismaleimide, N, N- (3,3′-dimethyl-4,4′-diphenylene) bismaleimide, N, N '-(3,3-Dichloro-4,4'-biphenylene) bismaleimide, N, N'-(2,4-pyridyl) bismaleimide, N, N '-(2,6
-Pyridyl) bismaleimide, N, N '-(1,4-anthraquinonediyl) bismaleimide, N, N'-(m-tolylene) bismaleimide, N, N '-(p-
Tolylene) bismaleimide, N, N '-(4,6-dimethyl-1,3-phenylene) bismaleimide, N, N'-(2,3-dimethyl-1,4-phenylene) bismaleimide, N, N '-(4,6-Dichloro-1,3-phenylene) bismaleimide, N, N'-(5-chloro-1,3-phenylene) bismaleimide, N,
N '-(5-hydroxy-1,3-phenylene) bismaleimide, N, N'-(
5-methoxy-1,3-phenylene) bismaleimide, N, N '-(m-xylene) bismaleimide, N, N'-(p-xylene) bismaleimide, N, N'-
(Methylenedi-p-phenylene) bismaleimide, N, N '-(isopropylidenedi-p-phenylene) bismaleimide, N, N'-(oxydi-p-phenylene) bismaleimide, N, N '-(thiodi- p-phenylene) bismaleimide,
N, N '-(dithiodi-p-phenylene) bismaleimide, N, N'-(sulfodi-p-phenylene) bismaleimide, N, N '-(carbonyldi-p-phenylene) bismaleimide, α, α- Bis- (4-maleimidophenyl) -meta-diisopropylbenzene, α, α-bis- (4-p-phenylene) bismaleimide and α, α-bis- (4-maleimidophenyl) -para-diisopropylbenzene.

Combinations of two or more bismaleimides, or bismaleimides and trimaleimides, or bismaleimides and higher polymaleimides in the compositions and processes of the invention are also equivalent. It is intended and understood by those skilled in the art that such tri- and higher polymaleimides and their substitutions for the compounds and processes specifically exemplified herein to practice the invention are It is understood that such equivalents are well within the intended scope of the invention.

Biscitraconimides which may be wholly or partially substituted in place of the N, N′-m-phenylene bismaleimides mentioned above for reference include, by way of representative example: 1,2-N , N'-dimethylene biscitraconic imide; 1,2-N, N'-trimethylene biscitraconic imide; 1,5-N, N '-(2-methyl-pentamethylene) -biscitraconic imide; and N, N'-methylphenylene bis citraconimide.

Mixtures of biscitraconimides and mixtures of bismaleimides and biscitraconimides and those containing trimaleimides are also intended to be equivalents of the invention.

The biscitraconimides contemplated by the invention are all well known compounds, which, if not commercially available, can be readily synthesized by methods well described in the art. U.S. Pat. No. 5,292,815 provides in column 4 a detailed list of such methods. As mentioned above, the tri- and higher polycitraconimides can be prepared by similar methods and may be wholly or partially substituted in the compositions of the invention, such as those skilled in the art. It will be understood that the compounds and substitutions are sufficiently equivalent to those specifically exemplified herein and are well within the scope of the invention as intended to be equivalent.

Silicone elastomers intended to be useful in embodiments of the invention are peroxide crosslinkable dimethylvinyl substituted silicone derivative elastomers,
These are well known in the art. For example, John Wiley & So
ns, a1982, "Kirk Othmer Encyclopedia of
See Chemistry Technology ", Volume 20, page 943 et seq.

Sulfur-containing organic compounds capable of accelerating the sulfur vulcanization of polymers can be cross-linked with sulfur intended for use in the invention and are well known in the art. Many different classes of these compounds are known and are intended as equivalents.

R. T. Vanderbilt Company, Inc. Publishing, The V
anderbilt Rubber Handbook lists a number of types. Examples of these are benzothiazole, thiadiazole, sulfenamide, sulfenimide, dithiocarbamate, thiuram, imidazole, xanthate, and thiourea derivatives. Sulfur Compounds A general class of sulfur accelerators also includes: Sulfides, disulfides (eg, diallyl disulfide) polysulfides and aryl polysulfide compounds such as amylphenol polysulfides such as ATOFINA Chemicals, Inc. And other known sulphur-promoting polysulfide phosphates, dithiophosphates and / or phosphorus-containing compounds, sulfur-containing compounds.
Other sulfur-containing organic compounds capable of donating sulfur at the vulcanization temperature are known, but are not currently used for such reactions due to cost concerns, but are also contemplated as equivalents. It is a thing. Examples of these are 2- (2,4-cyclopentadiene-1-ylidene) -1,3-dithiolane compounds.

More particularly, one class of sulfur promoters suitable for use in the practice of the invention is the salts of disubstituted dithiocarbamic acids.

[0043]   These salts have the following general structure:

[Chemical 3] In the structure, X is an ion derived from a metal selected from the group consisting of nickel, cobalt, iron, chromium, tin, zinc, copper, lead, bismuth, cadmium, selenium and tellurium, or X is a quaternary ammonium salt. Is an ion, n can range from 1 to 6, is equal to the number of formal positive charges on the X ion, and R ₁ and R ₂ are independently carbon atoms 1 to
An alkyl of 7.

[0044]   Examples of disubstituted dithiocarbamic acid salts are:   Bismuth dimethyldithiocarbamate;   Cadmium diethyldithiocarbamate;   Cadmium diamyl dithiocarbamate;   Copper dimethyldithiocarbamate;   Lead diamyldithiocarbamate;   Celenediethyldithiocarbamate;   Celenedimethyldithiocarbamate;   Tellurium diethyldithiocarbamate;   Piperidine pentamethylene dithiocarbamate;   Zinc diamyldithiocarbamate;   Zinc diisobutyl dithiocarbamate;   Zinc diethyldithiocarbamate;   Zinc dimethyldithiocarbamate;   Copper dibutyl dithiocarbamate;   Sodium dimethyldithiocarbamate;   Sodium diethyldithiocarbamate;   Sodium dibutyl dithiocarbamate;   Zinc di-n-butyldithiocarbamate;   Zinc dibenzyldithiocarbamate.

A second class of sulfur promoters suitable for use in the invention comprises thiuram. They are prepared from secondary amines and carbon disulfide and have the following general structure:

[Chemical 4] In the structure, R ₃ is an alkyl group of 1 to about 7 carbon atoms or the R ₃ group on each particular nitrogen atom is linked together with the nitrogen atom to which they are attached, carbon atoms 4,
A 5-, 6- or 7-membered heterocyclic ring containing 5 or 6 respectively may be formed and n is
It may have a positive value from greater than 0 to 6.

[0046]   Representative examples of thiuram sulfur promoters are:   Dipentamethylene thiuram tetrasulfide and hexasulfide;   Tetrabutyl thiuram disulfide;   Tetramethylthiuram disulfide;   Tetraethylthiuram disulfide;   Tetramethylthiuram monosulfide;   Isobutyl thiuram disulfide;   Dibenzylthiuram disulfide;   Tetrabenzyl thiuram disulfide;   Tetraisobutyl thiuram disulfide;   Isobutyl thiuram monosulfide;   Dibenzylthiuram monosulfide;   Tetrabenzyl thiuram monosulfide;   Tetraisobutyl thiuram monosulfide.

[0047]   The higher multisulfides of various thiurams are also sulfur donors.

Derivatives of thiadiazole include, but are not limited to: monobezoyl derivatives of dimercaptothiadiazole (2,5-dimethyl-1.3.4-thiadiazole); VANA of Vanderbilt Rubber Company.
A labeled thiadiazole identified as X® 189; 1,2,4-thiadiazole, 5-ethoxy-3- (trichloromethyl) thiadiazole; and an alkylmercaptothiadiazole, such as methylmercaptothiadiazole.

[0049]   Derivatives of benzothiazole have the following general structure:

[Chemical 5] In the structure, M is a direct bond between two sulfur atoms, H, or nickel, cobalt,
An ion derived from a metal selected from the group consisting of iron, chromium, tin, zinc, copper, lead, bismuth, cadmium, selenium and tellurium; when M is H, x is 1; X is 1 or 2 when it is a direct bond between sulfur atoms; x is equal to the formal valence of the metal ion when M is an ion derived from a metal; If it is a direct bond between and if x is 1, then the second sulfur atom to which the M bond is attached is also attached to the 4-morpholinyl radical.

Exemplary compounds are: 2- (4-morpholinodithio) benzothiazole; benzothiazyl disulfide; 2-mercapto-benzothiazole; 2-mercaptobenzothiazole disulfide; sodium-2-mercaptobenzothiazo. Zinc-2-mercapto-benzothiazole; Zinc-2-mercaptobenzothiazolate; Copper-2-mercaptobenzothiazolate; 2-N-cyclohexylaminobenzothiazole; N-cyclohexylamino-2-benzothiazole polysulfide 2-bisbenzothiazole-2; 2-polysulfide and 2-bisbenzothiazole-2,2-disulfide; bis (2,2'-benzothiazyldisulfide).

Sulfenamide accelerators are also well known. Specific examples are: N
-Oxydiethylene-2-benzothiazole sulfenamide; N-oxydiethylene thiocarbamyl-N-oxydiethylene sulfenamide; N-cyclohexyl-2-benzothiazole sulfenamide; Nt-butyl-2-benzothiazole Sulfenamide; N-cyclohexyl-2-benzothiazyl sulfenamide; N, N-dicyclohexylbenzthiazyl sulfenamide; N-
t-Butyl-2-benzothiazole sulfenamide. There are also sulfenamide compounds, such as Nt-butyl-benzothiazole-2-sulfenimide.

Representative imidazoles are: 2-mercaptobenzimidazole;
2-mercaptomethylbenzimidazole; and zinc salt of 2-mercaptobenzimidazole.

[0053]   Zinc isopropyl xanthate is a typical xanthate sulfur promoter.

Representative thioureas are: trimethylthiourea; 1,3-diethylthiourea and 1,3-dibutylthiourea; ethylenethiourea; blends of dialkylthioureas; diphenylthiourea; dioltotolylthiourea;
Dimethylthiourea; Diethylthiourea; Dibutylthiourea.

Alkylphenol disulfide types of sulfur accelerators are ATOFINA C
chemicals, Inc. To VULTAC (registered trademark) 2 and VULTAC 3
And VULTAC5.

Thiophosphate sulfur accelerators are exemplified by compounds such as: copper dialkyldithiophosphates; zinc dialkyldithiophosphates; zinc amine dithiophosphates; zinc dibutyldithiophosphates; copper O, O-diisopropylphosphorodithiolates. Zinc O, O-diisopropylphosphorodithiolate.

Other miscellaneous sulfur promoters are 4,4-dithiodimorpholine; N, N′-
Caprolactam disulfide; including dibutylxanthogen disulfide.

Polymers that are capable of curing (crosslinking) in the presence of molecular oxygen have hydrogen (or other removable atoms such as iodo- and bromo-substituted fluoroelastomers) removed or through a double bond. It includes all those natural and synthetic polymers that can be crosslinked either by being polymerized.

The presence of free radicals, which are presently considered not crosslinkable by these mechanisms and which are generated from organic peroxides and azo initiators which are defined herein below and which are present in the present invention, are subject to degradation. Polymers that should be substantially avoided in the curable composition are: poly (vinyl chloride), poly (propylene), butyl rubber, epichlorohydrin polymers and epichlorohydrin ethylene oxide polymers. As used herein and in the claims when referring to polymers suitable for use in connection with the invention, the terms "comprising,""consisting essentially of," and "consisting of" are used. Reference to polymers is explicitly to exclude more than a small insignificant amount (1% by weight or less) of non-free radical crosslinkable polymers in the absence of the opposite expression statement. .

Polymers crosslinkable by free radicals from organic peroxides and azo initiators as defined herein below include: ethylene-propylene terpolymers (EPDM), ethylene-propylene copolymers (EPM). , Natural polyisoprene rubber (NR), styrene butadiene rubber (SBR), polybutadiene rubber (BR), synthetic polyisoprene rubber (IR), poly (ethylene) (PE)
, Ethylene-vinyl acetate (EVA), acrylonitrile-butadiene-styrene (ABS), unsaturated polyester, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), neoprene rubber (CR), Nitrile rubber (NBR), polysulfide rubber (T), chlorinated poly- (ethylene) (CM), polyurethane (AU, E
U), vinylidene fluoride copolymer (CFM), silicone rubber (PMQ), vinyl silicone rubber (VMQ, PVMQ), polyacrylate (ACM), chlorosulfonated poly (ethylene) (CSM) and fluorosilicone rubber (FVM)
Q).

Suitable free radical initiators (organic peroxides and azo initiators) for use in the invention include organic peroxide and azo initiators suitable for curing (crosslinking) both polymers, thermoplastics and elastomers. Includes all those classes of agents.

Azo initiators for generating free radicals on thermal decomposition capable of inducing the desired curing (crosslinking) reaction are suitable initiators such as 2,2′-azobis- (2-acetoxypropane). It is known in the field. US Patent 3,862,107
Nos. 4,129,531 and azo initiators are also suitable, and their US patents are incorporated herein.

Except for hydroperoxides and liquid peroxydicarbonates, those organic peroxides known to generate free radicals that are capable of undergoing thermal decomposition to initiate the desired curing (crosslinking) reaction are known from the invention. Intended to be suitable for use in. Dialkyl peroxide, diperoxy ketal, mono-peroxy carbonate, cyclic ketone peroxide, diacyl peroxide,
Organosulfonyl peroxides, peroxyesters and solid, room temperature stable peroxydicarbonates are suitable initiators. The most preferred initiators are dialkyl peroxides, diperoxy ketals, cyclic ketone peroxides and diacyl peroxides.

A good reference providing important peroxide names and physical properties for all of these classes of organic peroxides is Kirk Othmer Encyclo.
Pedia of Chemistry Technology, 4th edition, 18
Vol. (1996), Jose Sanchez and Terry N. et al. It can be found in "Organic Peroxides" by Myers.

Illustrative dialkyl peroxides are: di-t-butyl peroxide; t-butyl cumyl peroxide; 2,5-di (cumylperoxy) -2,5-dimethylhexane; 2,5- Di (cumylperoxy) -2,5-dimethylhexyne-3; 4-methyl-4- (t-butylperoxy) -2-pentanol; 4-methyl-4- (t-amylperoxy) -2- Pentanol; 4-Methyl-4- (cumylperoxy) -2-pentanol; 4-Methyl-4- (t-butylperoxy) -2-pentanone; 4-Methyl-4- (t-amylperoxy)- 2-Pentanone; 4-Methyl-4- (cumylperoxy) -2-pentanone; 2,5-Dimethyl-2,5-di (t-butylperoxy) hexane; 2,5-Dime Cyl-2,5-di (t-amylperoxy) hexane; 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; 2,5-dimethyl-2,5-di (t- 2,5-dimethyl-2-t-butylperoxy-5-hydroperoxyhexane; 2,5-dimethyl-2-cumylperoxy-5-hydroperoxyhexane; 2,5-dimethyl- 2-t-amylperoxy-5-hydroperoxyhexane; m / p-alpha, alpha-di [(t-butylperoxy) -isopropyl] benzene; 1,3,5-tris (t-butylperoxyisopropyl) benzene; 1,3,5-Tris (t-amylperoxyisopropyl) benzene; 1,3,5-Tris (cumylperoxyisopropyl) Diene, di [1,3-dimethyl-3- (t-butylperoxy) butyl] carbonate; di [1,3-dimethyl-3- (t-amylperoxy) butyl] carbonate; di [1,3-dimethyl- 3- (cumylperoxy) butyl] carbonate; di-t-amyl peroxide; t-amyl mill peroxide; 2,4,6-tri (butylperoxy) -s-triazine; 1,3,5-tri [1] -(T-Butylperoxy) -1-methylethyl] benzene; 1,3,5-tri [1- (t-butylperoxy) -isopropyl] benzene; 1,3-dimethyl-3- (t-butylperoxy) Butanol; 1,3-dimethyl-3- (t-amylperoxy) butanol; and mixtures thereof.

Illustrative solid, room temperature stable peroxydicarbonates include, but are not limited to: di (2-phenoxyethyl) peroxydicarbonate; di (4-t-butyl-cyclohexyl) peroxydicarbonate. Dimyristyl peroxydicarbonate; dibenzyl peroxydicarbonate; di (isobornyl) peroxydicarbonate.

Another suitable class of dialkyl peroxides which may be used alone or in combination with other free radical initiators contemplated by the invention is selected from the group represented by the formula:

[Chemical 6] Wherein R ₄ and R ₅ may independently be in the meta or para position, are the same or different and are selected from hydrogen or a straight or branched chain alkyl group of 1 to 6 carbon atoms.
Examples are dicumyl peroxide and isopropyl cumyl mill peroxide.

Other dialkyl peroxides are: 3-cumylperoxy-1,3-dimethylbutylmethacrylate; 3-t-butylperoxy-1,3-dimethylbutylmethacrylate; 3-t-amylperoxy-1. , 3-Dimethylbutylmethacrylate; tri (1,3-dimethyl-3-t-butylperoxybutyloxy) vinylsilane; 1,3-dimethyl-3- (t-butylperoxy) butyl N- [1- {3- (
1-Methylethenyl) phenyl} -1-methylethyl] carbamate; 1,3-dimethyl-3- (t-amylperoxy) butyl N- [1- {3- (
1-Methylethenyl) phenyl} -1-methylethenyl] carbamate; 1,3-dimethyl-3- (cumylperoxy) butyl N- [1- {3- (1-
Methylethenyl) phenyl} -1-methylethyl] carbamate.

Within the group of diperoxyketal initiators, suitable initiators are: 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane; 1,1-di (T-butylperoxy) cyclohexane; n-butyl 4,4-di (t-amylperoxy) valerate; ethyl 3,3-di (t-butylperoxy) butyrate; 2,2-di (t-amylperoxy) propane 3,6,6,9,9-pentamethyl-3-ethoxycarbonylmethyl-1,2
, 4,5-Tetraoxacyclononane; n-Butyl 4,4-bis (t-butylperoxy) valerate; Ethyl 3,3-di (t-amylperoxy) butyrate; and mixtures thereof.

Other peroxides falling within the general class of compounds defined as useful in the invention are benzoyl peroxide, 00-t-butyl-0-hydrogen-monoperoxy-succinate and 00-t-amyl-. 0-hydrogen-monoperoxy-
Including succinate.

Illustrative cyclic ketone peroxides are compounds having the general formula (II), (III) and / or (IV):

[Chemical 7] In the formula, R _{1 to} R ₁₀ are independently hydrogen, C _{1 to} C ₂₀ alkyl, C _{3 to} C ₂₀ cycloalkyl, C _{6 to} C ₂₀ aryl, C _{7 to} C ₂₀ aralkyl and C _{7 to} C ₂₀ alkaryl. select from the group consisting of said groups, linear or branched may include alkyl properties, each of R ₁ to R _{1 0} is hydroxy, C ₁ -C ₂₀ alkoxy, linear or branched C ₁ To C ₂₀ alkyl, C _{6 to} C ₂₀ aryloxy, halogen, ester, carboxy, nitrido and amide, which may be substituted with one or more groups and are used for the crosslinking reaction. At least 20% of the oxygen content is (II
), (III) and / or (IV).

Some examples of suitable cyclic ketone peroxides are: 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane (or methyl ethyl ketone peroxide cyclic trimer) ) And methyl ethyl ketone peroxide cyclic dimer; 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane; illustrative suitable peroxyesters are: 2,5 -Dimethyl-2,5-di (benzoylperoxy) hexane; t-butylperbenzoate; t-butylperoxyacetate; t-butylperoxy-2-ethylhexanoate; t-amylperbenzoate; t-amylperoxyacetate; t-amyl peroxyisobutyrate; 3-hydroxy 1,1-Dimethyl t-butylperoxy-2-ethylhexanoate; 00-t-amyl-0-hydrogen-monoperoxy-succinate; 00-t-butyl-0-hydrogen-monoperoxy-succinate; di-t -Butyl-diperoxyphthalate; t-butylperoxy (3,3,5-trimethylhexanoate); 1,4-bis (t-butylperoxycarbo) cyclohexane; t-butylperoxy-3,5,5-trimethyl Hexanoate; t-Butyl-peroxy- (cis-3-carboxy) propionate; Allyl 3-methyl-3-t-butylperoxybutyrate.

Illustrative monoperoxycarbonates are: 00-t-butyl-0-isopropylmonoperoxycarbonate; 00-t-butyl-0- (2-ethylhexyl) monoperoxycarbonate; 1,1,1 -Tris [2- (t-butylperoxy-carbonyloxy) ethoxymethyl] propane; 1,1,1-Tris [2- (t-amylperoxy-carbonyloxy) ethoxymethyl] propane; 1,1,1-Tris [2- (cumylperoxy-carbonyloxy) ethoxymethyl] propane; OO-t-amyl-O-isopropyl monoperoxycarbonate.

[0074]   Illustrative diacyl peroxides are:   Di (4-methylbenzoyl) peroxide;   Di (3-methylbenzoyl) peroxide;   Di (2-methylbenzoyl) peroxide;   Didodecanoyl peroxide; dilauroyl peroxide;   2,4-dibromo-benzoyl peroxide;   Succinic acid peroxide;   Dibenzoyl peroxide;   Di (2,4-dichloro-benzoyl) peroxide.

Imide peroxides of the type described in PCT application publication WO9703961 A1 of February 6, 1997 are considered suitable for use in the invention.

One of ordinary skill in the art can readily select suitable amounts of the various components for use in the invention, with a series of increasing amounts of the components employed in the sample of polymer to be cured (crosslinked). The bench scale trial will allow you to easily optimize the concentration in a short time. Optimal processing (compounding) times and temperatures, etc. may also be determined from the same trial, as will optimal cure times and temperatures.

In the composition of the invention, the compound of formula (a) (bismaleimide and biscitracone imide) is from about 0.2 parts by weight per part polymer (phr) to about 10 parts by weight.
． 0 phr, preferably about 1.0 phr to about 5.0 phr, most preferably about 1 phr.
． It will typically be employed in an amount of from 5 phr to about 3.0 phr.

About 0.01 phr to about 20 phr of a sulfur-containing organic compound capable of promoting sulfur vulcanization in a polymer capable of being cross-linked by sulfur in the composition of the invention.
r, preferably about 0.1 phr to about 1.0 phr, most preferably about 0.1 phr
It will typically be employed in an amount of from r to about 0.5 phr. Those skilled in the art will understand that there are two types of these compounds, those that provide sulfur for vulcanization and those that readily accelerate sulfur vulcanization. The invention contemplates either class of compounds or mixtures thereof being equivalent.

VULTAC type alkylphenol disulfide polymers are preferably used at about 0.5 phr to 20 phr when used alone or at about 0.1 phr to about 10 phr when combined with other sulfur promoters.

About 0.04 of free radical initiator (organic peroxide and / or azo initiator)
It will typically be used in an amount of from about 10 to about 10 phr, preferably from about 1 to about 4 phr.

The time-temperature conditions required for curing are largely dependent on the structure of the free radical curing agent. Suitable conditions for azo initiators are detailed in US Pat. Nos. 3,632,107 and 4,129,531.

For the compositions of the invention, suitable time and temperature conditions ran a small number of well-controlled rheometer studies and the results of those studies indicate that the time / temperature relationship indicates that free radicals within the system are free radicals. It may be determined for cross-linking a particular polymer composition by choosing a value that is 5 to 15 times the half-life of the initiator.

The invention provides antioxidants (preferably hindered phenols and polymeric quinoline derivatives), aliphatic process oils and other process auxiliaries, pigments, dyes, tackifiers, waxes, reinforcing auxiliaries, UV. It is contemplated that other conventional additives such as stabilizers, foaming agents, activators and antiozonants may also be present in the composition before, after and during the curing step.

Polysulfide polymers contemplated by the invention are those known polysulfides prepared by reacting an α, ω-dihaloalkyl (or dihaloheteroalkyl) compound with a metallic, preferably alkali metal, polysulfide. It is a polymer. Generally, commercially available polysulfide polymers are either liquid or solid, have either thiol or hydroxy end groups,
- dichloroethane, 2,2-dichloro - diethyl ether or bis (2-chloroethyl) formal and alkali metal polysulfide (MSx _x) (where, M
Is an alkali metal ion, preferably an ion derived from sodium, and x is a number greater than 1 and up to about 6) derived from a substance prepared by reacting with.

The invention contemplates that the polysulfide polymer may be used instead of or in admixture with other compounds (B) in amounts equal to those specified above for those compounds. . Also, since excess polysulfide polymer does not appear to be detrimental to the practice of the invention, they are preblended with compound (A) and optionally a free radical initiator to form a masterbatch, either solid or liquid. It is also contemplated that it may be formed. It is also possible to pre-blend the polysulphide polymer into the polymer to be cured and to compound (A) and also the free-radical initiator simultaneously or subsequently at the operator's option. The use of polysulfide polymers in combination with other sulfur promoters contemplated by the invention allows the invention to reduce the amount of sulfur promoters required.

Similarly, the polysulfide polymers themselves are free radical initiated in the presence of molecular oxygen if compound (A) is present in the curable composition, even in the absence of another compound (B). It will be apparent to those skilled in the art that the agent may cure to a tack free surface. Thus, the invention intends such compositions to be equivalent to the second composition aspect of the invention as defined above.

Certain crosslinkable elastomeric compositions highly loaded with oil and / or carbon black (generally referred to as highly weighted elastomer formulations) are cured using sulfur vulcanization rather than free radical initiator. It is usually done. Free radical cure is more difficult because the radicals generated lack specificity and react with fillers and oils and elastomers. This reduces the efficiency of the free radical initiator.

The use of chlorinated polyethylene and / or chlorosulfonated polyethylene as a supplement to all of the compositions of the various composition embodiments of the invention surprisingly improves free radical cure efficiency in highly extended elastomer formulations. It has been found to increase freezing and to allow free radical cure of the system with reduced or no tack. The amount of chlorinated and / or chlorosulfonated polyethylene as a trapping component in the composition of the first composition aspect of the invention is from about 1 to about 50% by weight, preferably from about 15 to about 40% by weight, more preferably Can be 20-35% by weight.

Incorporation of these two polymers as supplemental components, in some cases, in some cases the composition of the first composition aspect of the invention in the formulation of the composition of the second composition aspect of the invention. It has been found to allow use at lower concentrations.

The following examples illustrate the best mode contemplated by the invention for carrying out the invention and are illustrative of the invention and are not to be construed as limiting the invention.

[0091] Examples Example 1 - EPM evaluation of effects to be given to the prior art compositions Narabiniso these sticky and crosslinking level for crosslinking in the presence of air. In this example, various known co-curing agents, such as unsaturated monomeric cross-linking co-agents, elemental sulfur, or element donor compounds were evaluated in curing with organic peroxides. The elastomer used in this example is VISTALO manufactured by Exxon.
It was an ethylene propylene copolymer (EPM) sold under N® 504. The prior art (US Pat. No. 4,983,685) has a high level (2.5
~ 20 parts) of a particular sulfur-containing compound, with or without an optional unsaturated monomer, is used to crosslink the elastomer with peroxide in the presence of air to produce a tack free surface. It claims that it can. Other references employ sulfur. In this example, low levels of sulfur or sulfur donor compounds were evaluated alone or with some monomeric co-agents. The data in Table 1 show that these formulations produced stickiness, but also resulted in crosslinked products with good physical properties (higher MH torque). A blend of optional monomeric co-drug, high levels of sulfur compounds and peroxides (as taught by the prior art) was also evaluated. This produced a tack free surface when the elastomer was crosslinked in the presence of air, but the physical properties were unacceptable compared to conventional peroxide monomeric crosslinking formulations.

In the formulations of Table 1, standard carbon black formulations were used. Carbon black (N774), Sunpar® LW150 process oil from Sun, zinc oxide, antioxidant (AgeRite MA) was incorporated into the EPM. In addition, all formulations contain 40% Acai Organic Peroxyketal Peroxide, AT
OFINA Chemicals, Inc. 8 parts of LUPEROX® 231XL [1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane 40%] dispersed on calcium carbonate, sold by K.K. The level of cross-linking was determined using a Flexsys MDR® 2000E Mobile Die Rheometer. The sample was also cured in hot air at 365 ° F. (185 ° C.) for 10 minutes and the tack was determined by placing a paper towel on the surface immediately after removal from the oven using moderate and consistent pressure. . The tackiness was rated from 1 to 10, with 1 being considered non-tacky, 10 being very tacky.

Although the combination of peroxide with low levels of elemental sulfur, 0.3 parts (typical EPM cure) (Table 1, Run # 1) resulted in good levels of crosslinking based on M _H. Resulted in tackiness when cured in hot air. HVA-2 (Dupon
Using 2 parts of the N, N′-phenylene bismaleimide) co-drug marketed by t with peroxide (Table 1, Run # 2), the expected improved standard levels of cross-linking (based on _MH) ), But the stickiness, unfortunately, is poor. Note : In each case the antioxidant AgeRite MA (RT Va)
1 part of polymerized quinoline sold by Nderbilt, a level that does not affect the surface is used. The combination of elemental sulfur, 0.3 parts and 2 parts HVA-2 (Table 1, Run # 5) results in a further improvement in the level of crosslinking (HVA-2.
(Compared to Run # 2, which used A. alone), unfortunately provides high tack (7 out of 10). From this, a blend of co-agent and low levels of elemental sulfur
Crosslinking can be improved, but tack cannot be improved. The prior art teaches that 2.5 to 20 parts of sulfur accelerator or its equivalent is required. The use of the co-agents HVA-2 and peroxide in carbon black EPM formulations containing oil and antioxidant resulted in good cross-linking, unfortunately also
It produced tackiness when cured in hot air. Monomeric co-agent SR-350 (
The use of 4 parts (registered trademark) with 0.3 parts of elemental sulfur resulted in the highest level of cross-linking but poor adhesion (see Table 1, Run # 4). SR
-350 is trimethylolpropane trimethacrylate sold by Sartomer.

Table 1, Run # 3, 1.2 parts of Sulfads® in combination with peroxide resulted in an unacceptable tack of 6 out of 10 and an undesired level of cure based on M _H. It was Sulfads, R. T. Vanderbi
98% dipentamethylene thiuram tetrasulfide sold by lt; from which the actually added dipentamethylene thiuram tetrasulfide is 1.
It was 2 × 0.98 to 1.18 parts. Finally, 1.2 parts of Sulfads will be added to HVA
-2 when used in combination with 2 parts and peroxide gives a good surface when cured in hot air, but, unfortunately, was crosslinked as desired as indicated by the low _MH values achieved. The physical properties are reduced.

This example is intended to keep peroxides, monomeric co-drugs and dissimilar co-agents such as elemental sulfur or sulfur-containing compounds with the purpose of keeping acceptable levels of crosslinking when cured in the presence of air with low tack. It illustrates that the effect of blending hardeners cannot be predicted. Imagine that if the level of global cross-linking could be improved by various co-drugs and peroxides, the tackiness in the presence of air could be improved. However, our data show that when cured in the presence of air, the level of cross-linking can be improved without increasing tack.

In addition, when cross-linking was finally reduced using the teachings from the prior art, global crosslinking was found to be undesirable. Cross-linking within the sample (excluding air) and cross-linking the surface in the presence of air are two different processes. Increasing or decreasing the level of cross-linking co-agent or using various co-curing agents in combination with peroxide leads to unpredictable results. HVA-2
Cross-linking co-agents such as help to increase the level of cross-linking by peroxide cure, but appear to result in poor tack on air cure. We have combined monomeric co-agents such as HVA-2 or SR-350 with other co-curing agents such as elemental sulfur or sulfur donor / promoter compounds as taught in the art. It has been found that the final physical properties are severely reduced when used as such, thus overriding the advantages of the monomeric co-drug-peroxide curing system.

[0097]

[Table 1]

[0098] Example 2 - formulating fully saturated (no double bonds in the polymer chain) peroxide formulations of the prior art for the elastomer to call bridge pairs novel peroxide formulations. The novel peroxide formulations bring the good physical properties associated with conventional peroxide curing with the addition of an unexpected tack-free surface when cured in the presence of air.

In this example, EPM (Polyethylene Propylene Copolymer) VISTALON® was prepared using 40% azedicumyl peroxide dispersed on clay.
707 (Exxon) was crosslinked. Table 2, Run # 1, SR 206 (ethylene glycol dimethacrylate) was blended with dicumyl peroxide and evaluated for cross-linking in MDR,% compression set and tack in hot air cure. Note : Prior art (US Pat. No. 4,983,685) uses SR 2 in their example.
06 was used as an optional monomeric co-drug. This peroxide and co-drug blend has a good cure ( _MH ) upon hot air cure at 400 ° F (204 ° C).
And% compression set was produced with a very tacky surface. Sulfads (9
Addition of 8% dipentamethylene thiuram tetrasulfide) to the peroxide SR 206 blend at the level of 2.5 parts claimed in the prior art improved the surface but completely destroyed% compression set. Yes; Table 2, Run # 2.

Prior art level Sulfad in the specification of US Pat. No. 4,983,685.
s 0.8 parts, Table 2, run # 4, optional HVA-2 co-agent 2.2 parts, DC40
When used with 5 parts it gave a good surface but very poor% compression set.
Brought. Note : A compression set percentage value of 100-60% would be expected for sulfur vulcanization and not for peroxide crosslinking.

Table 2, Run # 3, 5 parts of the prior art taught level Vanox ZMTI (93% zinc mercapto-toluimidazole), with optional SR 206 co-agent, improved compression set but significantly. It gave a sticky and unacceptable surface.

Unexpectedly, Table 2, Run # 5, low levels of dipentamethylene thiuram tetrasulfide (0.4 parts outside the scope of US Pat. No. 4,983,685),
0.4 parts Durax (98% N-cyclohexyl-2-benzothiazole sulfenamide) and 5 parts DC40 (40% dicumyl peroxide) improve the tack-free surface when cured in a hot air oven. With a compression set of 41% and a better level of crosslinking.

Table 2, run # 6 unexpectedly shows that Durax 0.4 part, Vanax
0.4 parts of A (98% 4,4'-dithiodimorpholine), 2.2 parts of HVA-2 monomeric co-drug and 5 parts of DC40 (40% dicumyl peroxide) were applied to the non-sticky surface. It shows that the compression set was brought together with 31%. The use of Durax and / or Vanax A with peroxides and bismaleimide type co-agents for use in hot air cure of elastomers is not taught in the prior art. Table 2, Run # 7, Substituting 0.8 parts Durax for the Durax / Vanax A blend resulted in a further unexpected significant compression set of 21% when hot air cured at 400 ° F (204 ° C). Brought with a tack free surface.

Finally, Table 2, Run # 8, yielded unexpected and remarkable results; HVA-2.
Excellent tack free surface with very desirable very low compression set 18% using 2.2 parts, 0.4 parts VULTAC5, 0.4 parts Durax and 5 parts DC40. VULTAC5, a 75% alkylphenol disulfide polymer from Elf Atochem, has not been taught by the art for use in the hot air cure of elastomers with peroxide and bismaleimide type co-agents. It is noted that 0.4 parts of VULTAC5 is equivalent to adding 0.3 parts of alkylphenol disulfide polymer with 75% acid.

This example demonstrates that a prior art formulation in which selected compounds such as peroxide and high levels of dipentamethylene thiuram tetrasulfide were blended with an optional monomeric co-drug was actually tacky. It is shown to produce a non-existent surface, but results in very poor final physical properties for the crosslinked elastomer. The thiuram preferred compounds taught by the disclosure of the prior art U.S. Pat. No. 4,983,685 contain 0 to less than 2.5 to 20 parts as claimed.
． Used at 8 parts, it produced crosslinked elastomers with very poor heat aging properties for peroxide cured formulations.

A high compression set value of 60% + indicates that prior art crosslinked polymers are a standard test for peroxide curing (ASTM D-395-61), 150.
It shows a permanent deformation under pressure applied at 70 ° C. for 70 hours. A tack free surface can be obtained for unsaturated polymers by hot air sulfur vulcanization, but results in poor heat aging properties. There is no advantage over sulfur vulcanization to peroxide cure systems cured in hot air unless there is a significant difference in physical properties such as low _MH and / or high (poor) compression set percentage values. . Peroxide cure has traditionally been the pick for many high temperature and high performance applications. Peroxide crosslinking provides a carbon-carbon bond that allows the crosslinked polymer manufacturer to use the full engineering capabilities of the elastomer.

[0107]

[Table 2]

Example 3 -The novel peroxide-additive composition produces a solid or foamed crosslinked elastomer in hot air with outstanding physical properties , such as percent compression set, while also in the presence of air. It also forms a tack-free surface when cured. The elastomer used in this example was Uniroyal® X3378 EPDM containing 4% dicyclopentadiene as the termonomer.
Peroximon DC 40KEP (40% dicumyl peroxide on clay) was used as the peroxide crosslinker. In this example, peroxide and HVA-
Varying levels of Sulfads (98% dipentamethylene thiuram tetrasulfide), VULTAC5 (75% alkylphenol disulfide polymer) and Durax (98% N-cyclohexyl-2-benzothiazole sulfenamide) while keeping the two co-agents constant. (Table 3, runs # 2 to # 6).

Note : Addition of 0.5 parts (phr) Sulfads corresponds to 0.49 parts dipentamethylene thiuram tetrasulfide per 100 parts rubber. Run # 2
, # 3 and # 4, unexpectedly, dipentamethylene thiuram tetrasulfide was added at 0.5 ph on pure basis with HVA-2 and peroxide.
Excellent compression set and tack free surfaces were observed when used in amounts less than r.

Sulfads (98% dipentamethylene thiuram tetrasulfide), VU
When varying LTAC5 and Durax concentrations, it was unexpectedly discovered that our novel peroxide / additive composition can be used to produce both solid and foamed crosslinked elastomers by hot air cure. I found it. When pure dipentamethylene thiuram tetrasulfide <0.5 phr was used with either VULTAC5 or Durax, a foamed crosslinked elastomer with a tack free surface was obtained; Table 3, Runs # 2, # 3. And # 4. VUL
Using TAC5 or a blend of VULTAC5 and Durax resulted in a solid crosslinked EPDM, Table 3, runs # 5 and # 6. Unexpectedly, in each case (Table 2, Runs # 2- # 6), significant compression set percent values were obtained which were virtually equivalent to the conventional peroxide cures listed in Table 2, Run # 1.

Sulfur vulcanization compression set is measured at about 100 ° to 120 ° C. and is rarely required at 150 ° C. because performance always fails at high temperatures. Book 150 ℃,
The desired compression set data of 70 hours demonstrates that these novel peroxide-additive compositions exemplified in the practice of the present invention produce crosslinked EPDM with unexpectedly good heat aging properties. In addition, a novel peroxide-
The additive composition surprisingly provides a method for producing both solid and foam articles.

While not wishing to be bound, faster burn times were earlier in the cure to provide a solid cured product. Related to unexpected cross-linked network setup faster than gassing from the cure system. This is believed to be the case, and this is more difficult under low pressure conditions in the furnace as opposed to a closed mold. When delaying the bake time, gassing can occur simultaneously with the crosslinked network formulation. Moreover, these novel peroxide formulations provide, in addition to these various unexpected processing and engineering advantages, a completely tack-free surface when cured in the presence of air.

[0113]

[Table 3]

[0114] Example 4 - Novel peroxide - the additive composition, fast cure in Table 4, using even higher have ethylene EPDM (Royalene 509 EPDM), is studied using Jikumi Ruperuokishido and HVA-2. The prior art formulations (Table 4, Runs # 2 and # 3) provided good surfaces after hot air curing, but unfortunately resulted in very poor 150 ° C./70 hour compression set physical properties and were extremely poor. It showed an unpleasant odor. These compression set values 61
% And 71% are similar to those obtained from sulfur vulcanization and not similar to those obtained from peroxide cure. In addition, prior art samples # 2 and # 3 using 2.5 parts of Sulfads trapped large air bubbles in the center of the cured part; these were considered unacceptable cure defects.

In contrast, all samples using the novel peroxide-additive composition taught by the present invention (Runs # 5 to # 12) had outstanding physical properties, namely 150 ° C. /
It gave very low compression set values at 70 hours, these properties being very similar to those obtained by using the peroxide control reaction without co-agent or sulfur additive (Table 1, Run # 1). Was. The control reaction gave a compression set value of 15% despite the fact that the surface was very tacky (10 out of 10) for hot air cure studies. A blend of HVA-2 co-drug with peroxide and antioxidant AgeRite D (typically incorporated into rubber formulations as standard practice) (Run # 4) was tested at a reduced 120 ° C / 70 hours. It gave good compression set values at temperature, but unfortunately resulted in poor surfaces (7 out of 10) when cross-linked in the presence of air. All samples included in the present invention, Runs # 5 to # 12, provided the excellent physical properties associated with peroxide curing, plus a non-tacky surface when cured in the presence of air.

[0116]

[Table 4]

Example 5 -Bismaleimide co-drugs for use effect in providing good overall peroxide-type physical properties with the ability to cure the surface of rubber in the presence of air (non-sticky surface). general evaluation of co-drug class to demonstrate the Japanese sexual things used with selected the additives. Bismaleimide in combination with Sulfads and VULTAC5, along with dicumyl peroxide, provides a fast cure type EPDM (Royalene®).
509 EPDM) for crosslinking.

The teachings of the prior art use various co-agents, both monomeric and non-monomeric, to improve the crosslinking efficiency, but not their effect on air contact. The inventors have found that these various co-agents, for the bismaleimide type, are likely to increase the reaction with oxygen and make the rubber surface more tacky after curing in the presence of air. .

In Table 5, HVA-2 (bismaleimide-type co-drug) was labeled as Sulfads.
A blend of 0.3 parts and 0.2 parts VULTAC5 resulted in a tack free surface. Other agents such as TAC (triallyl cyanurate), S
R-350 (trimethylolpropane trimethacrylate), 1.2BR (1,
2 liquid butadiene rubber), Santolink XI-100 (allyl glycidyl ether alcohol resin), TAP (triallyl phosphate) and pBQ (
Parabenzoquinone) resulted in a tacky surface.

[0120]

[Table 5]

[0121] Example 6 - Using a blend of low levels of HVA-2 and Jikumiruperuoki Sid prior art sulfur accelerators, do not lead to non-existent sticky surface. Can not be expected, both when using a low level of the prior art compounds the HVA-2 and selection compound, resulting in a non-existent tacky surface when fast curing EPDM (Royalene 509) crosslinking in the presence of air. Methyl Zimate (98% zinc dimethyldithiocarbamate) 0.
The use of 2 parts or 0.2 parts Unads (98% tetramethylthiuram monosulfide) with HVA-2 resulted in a poor surface cure (sticky surface) when cured in the presence of air. Thus, very low levels of prior art compounds in combination with HVA-2 (N, N'phenylene bismaleimide) co-drugs and peroxides were used to provide a tack free surface for crosslinked elastomers in the presence of air. Is not trivial to bring.

Unexpectedly, VULTAC5 (75% alkylphenol disulfide polymer) or Vanax A (98% 4,4'-dithiodimorpholine) are blended with these low levels of prior art compounds such as Methyl Zimate or Unads. Sometimes a tack-free surface is obtained when cross-linked in the presence of air.

Thus, the unique blend of peroxide, HVA-2 co-drug, and low levels of dithiocarbamate or thiuram with VULTAC5 or Vanax A results in a crosslinked polymer with a cured surface in the presence of air. .
In addition, no degassing was observed, which is why these new blends
Solid, cross-linked moieties can be formed.

[0124]

[Table 6]

Example 7 -Using low levels of prior art elemental sulfur with low levels of prior art Sulf ads, with or without an optional HVA-2 monomeric co-drug , in hot air. Provides good surface hardening, but poor physical properties ( 61% and 49% compression set). From this, the concept of using lower levels of known prior art sulfur compounds with the proposed co-agents and peroxides does not readily lead to a combination of good surface hardening with the desired expected physical properties.

[0126]

[Table 7]

[0127] Example 8 - In this example, the novel peroxide - indicates that perform well in the additives composition EPDM Blend was filled is and unfilled EPDM formulations. Run # 2 contains only EPDM and the novel peroxide-additive formulation,
That is, it contains no oil, carbon black, ZnO or stearic acid. Note : The novel formulations as taught in the practice of the invention provide a completely tack free surface (1 out of 10) (where 10 is tack) when cured in the presence of air. Add normal levels of carbon black and oil (Run # 4)
, Resulting in a good non-sticky surface in the presence of air. Table 8, Run #
The use of high levels of carbon black (above EPDM usage) and high levels of oil as shown in 6 and # 8 shows the expected reduction in the level of crosslinking (M _H ) for organic peroxide type cures. However, the resulting surface hardening in the presence of air, when increasing the level of peroxide-additive blend,
Surprisingly good (4 out of 10) as shown in Run # 8. It is well known that peroxide cure is adversely affected by high levels of oil and carbon black. Peroxide radicals can easily abstract hydrogen from oils and gums. With increasing oil concentration, this significantly reduces the peroxide cure efficiency. This is shown by the decrease in M _H for the two peroxide controls without additives (comparing normal levels of oil and carbon black run # 3 to higher levels of oil and carbon black # 5).

[0128]

[Table 8]

Example 9- Hot air cure of very highly filled EPDM using the novel peroxide-additive blend . This highly filled EPDM contains large amounts of carbon black and oil. Such formulations are typically used only for sulfur vulcanization and not in peroxide cure. The successful use in these examples shows an unexpectedly large use effect of these novel peroxide-additive blends. In addition, the effectiveness of this system is illustrated by providing an example using four different organic peroxides. These are: LUPERO
X 231-XL = 40% 3,3,5-trimethyl-1,1-di (t-butylperoxy) cyclohexane; LUPEROX 230-XL = 40% n-butyl-4,4-di (t-butylperoxy). Valerate; Peroximon DC
40KEP = 40% dicumyl peroxide; and Peroximon F40K
EP = 40% di (t-butylperoxy) diisopropylbenzene.

The peroxide controls (Table 9, Runs # 1, # 3, # 5 and # 7) are all tacky due to undercure of the surface when cross-linked in the presence of air. They also contain some air bubbles inside the sample. The novel peroxide-additive formulations used in the present invention provide a fully cured surface (tack free) when crosslinked in the presence of air, Table 9, Runs # 2, # 4, # 6 and #.
See 8. Unexpectedly, these formulations cure to higher levels of cross-linking to the point where there was no foam (air bubbles) present. Thus, the novel peroxide formulations impart a tack-free surface upon hot air cure to the desired solid, crosslinked portion. The cure time varies from using different peroxides, but unexpectedly the surface is always tack-free despite the use of high amounts of filler and oil.

[0131]

[Table 9]

[0132] Example 10 - ADA a (azodicarbonamide), to originating gun agent used to make the fire products. In Table 10, hot air-cured, free-rise, crosslinked EPDM sponges were prepared using ADA and our novel peroxide-additive formulation to produce a non-tacky surface. make. Peroxide controls without additives or ADA are listed in Table 10, Run # 1. Note : The level of crosslinking is measured by a moving die rheometer (MDR 2000E, 200 ° C and 1 ° arc), M _H = 1
It was 9.8 inches-lb (22.8 cm-kg). However, it is noted that the surface was very tacky when crosslinked in the presence of air. Tangent delta for Run # 1 (peroxide control) is a desirable low value of 0.0
It was 64. MDR can measure tan delta (tan delta), which can be determined by dividing the viscous modulus by the elastic modulus. Cured compounds with very low tangent delta will be very elastic and exhibit low hysteresis. Higher tangent delta values mean that the polymer chains can undergo permanent migration or deformation after being stressed. Table 10, Run # 2, peroxide and ADA without other additives are:
Yielded _MH = 17.6 in-lb (20.3 cm-kg), so ADA
Appears to reduce the level of cross-linking compared to Run # 1 while still providing a tacky surface (although gas pressure may also affect reading).

Table 10, Run # 3, peroxide, ADA and co-drug blended with N, N′-m-phenylene bismaleimide (HVA-2) and 1,3-bis (citraconimidomethyl) benzene (Perkalink 900). Used to provide improved cross-linking performance based on the higher M _H = 24.9 in-lb (28.7 cm-kg), but after hot air curing the surface is very tacky. Met(
It was 7 out of 10). The co-agent, along with peroxide, helps to improve cure, but air suppression continues to lead to poor surfaces.

Table 10, Run # 4, low level of certain additives, ADA (no co-drug present), along with peroxide improve surface after hot air cure (4-5 out of 10). ), But the cross-linking is very low ( _MH = 14.9 in-lb (17.2 cm-).
kg)), the tangent delta is 0.095, which is not desirable.

Unexpectedly, when the co-drug blends (HVA-2 and Perkalink 900) according to our invention were used with low levels of selected additives, peroxides and ADA foams, excellent crosslink density (M). _H = 22.2 inches-l
b (25.6 cm-kg)) and a very good surface (10) when hot air cured.
2) out of (Table 10, Run # 5). Note : Density 30 pounds / ft ³ (
A uniform fired EPDM with 0.48 g / cm ³ ) was produced.

Table 10, Run # 7, Vanox ZMTI (9) as taught in the prior art.
ADA with 3% zinc 2-mercapto-toluimidazole to 5 phr peroxide
Used to provide a tack-free surface on hot air cure compared to Run # 5, but unfortunately the _MH is only 16.9 in-lb (19.5 cm-kg).
Low and correspondingly the Tangent Delta is poor.

The use of Captax (98% 2-mercaptobenzothiazole), Table 10, Run # 8 according to the prior art leads to a tack-free surface as well, but the final crosslinked physical properties ( _MH and tangent delta). ) Is further deteriorated.

[0138]

[Table 10]

[0139] EXAMPLE 11 - The general co-agent LUPEROX 101-XL [45% 2,5- dimethyl chill-2,5-di (t-butylperoxy) hexane] with sulfur donors - by adding the accelerator blend , Evaluate common co-drugs. These peroxide-co-drug-accelerator blends were used to cure standard EPDMs, using the bismaleimide-type co-drugs HVA-2 or Vanax.
We show that MBM is the only one tested that can provide all important combinations of good cure and non-tacky surface when EPDM is crosslinked in the presence of air.

Common co-drugs were compared to Royala 509 in Example 4 / Table 4 as compared to Royal.
More efficient in len® 521 EPDM. Referring to Table 11, Run # 5, only HVA-2 results in a tack-free surface when used in the practice of our invention in the presence of air and Table 11,
It has a higher MDR torque compared to the peroxide control in Run # 1.
While some of the co-drugs provide some less reproducible improvements, only bismaleimide-type co-drugs, unexpectedly with low levels of selected additives, have unexpected surface hardening and physical properties. Bring a remarkable balance of.

In addition, the previous data in Tables 5 and 11 show that among all co-drugs HVA-2 works well with low levels of additives in the practice of our invention. It is shown to have the fastest cure time, which results in a shorter cure time in air, resulting in a tack-free surface with excellent final physical properties. The shortening of the curing time is
It should help manufacturers improve productivity as well as produce better products.

Various ingredients used in Table 11 LUPEROX 101-XL [45% 2,5-dimethyl-2,5-di (t-butylperoxy) hexane] Sulfads (98% dipentamethylene thiuram tetrasulfide) Santocure TBSI (Nt-butyl-2-benzothiazole sulfenimide) TAIC (triallyl cyanurate) SR-350 (trimethylolpropane trimethacrylate) HVA-2 (N, N'-m-phenylene bismaleimide) DAM (diallyl) Meritate)

[0143]

[Table 11]

Example 12- Various peroxide-sulfur cure blends used for other applications were tested in terms of tack (quality) in air cure and percent compression set properties, the novel blends of this invention and standard peroxide and sulfur. Rank relative to cure . The novel peroxide cure system in Table 12, Run # 2 showed that the surface without good tack in air (1 out of 10) was very tacky (in 10) after curing in air. To 10) in Table 12, Runs # 1, # 3 and # 6, with a significant compression set equal to the peroxide cure. Table 12, Runs # 4 and # 5
The sulfur additive therein produces a poor surface without HVA-2, with higher, less desirable compression set values. Table 12, Runs # 7 and # 8
Semi-EV (semi-efficient sulfur vulcanization system) using low levels of elemental sulfur in
Gives an unexpectedly improved surface (tack free), but exhibits poor compression set values for such EV sulfur cures. Poor compression set values of 77% and 71% for the standard sulfur vulcanization system, Table 12, Runs # 9 and # 10 were excellent.
Provides a 16 percent compression set but a very tacky surface Table 12
, Runs # 1, # 3 and # 6, give a non-sticky surface with good tack.

[0145]

[Table 12]

Example 13- Storage stability of novel peroxide-formulations. The powder forms of these compositions can be premixed and stored for later use without loss of activity. In Table 13, runs # 3 and # 5 are Mix 1 and Mix 2, respectively, which were aged for 3 months at room temperature. These aged mixtures were compared with freshly prepared peroxide mixtures as shown in Table 13, Runs # 2 and # 5. The rheometer torque versus time curve and the quality of the crosslinked surface cured in hot air are the same, within experimental error, for both compounds. If the components reacted during aging, the MDR torque, time and quality would be closer to the control (Run # 1). In the practice of the invention, the various ingredients can be added, followed by the peroxide, but premixing the various additives makes it more practical and / or easier to use.

[0147]

[Table 13]

[0148] Example 14 - Use in low levels of antioxidants (phenolic, metal dimethyl dithiocarbamate formate type) was combined with bismaleimide co agents and low levels of sulfur donor, an elastomer cured in the presence of air brought at excellent adhesion nonexistent surface and also desired final physical properties (i.e., low have compression set) also results. The novel peroxide air cure formulations consisting of peroxide, bismaleimide co-agent, sulfur donor-sulfur accelerator system can also include low levels of antioxidants. Previously, in Example 4, Table 4, Run # 11, (M. Nicola
te, ie, Methyl Niclate) nickel dimethyldithiocarbamate at low levels of 0.2 phr, along with others, such as zinc (M.Zimate) and copper (M.Cumate) type dimethyldithiocarbamate.
Use with ads to successfully produce tack free surfaces with good physical properties (compression set). Methyl Niclate, whose chemical name is nickel dimethyldithiocarbamate, is sold as an antioxidant.

In this Example 14 and Table 14, at a low level of 0.28 phr of Methyl
Niclate is used in Run # 3 and compared to phenolic antioxidants and sulfenamide accelerators; Run # 6 MBPC (2,2'-methylenebis-4.
-Methyl-6-t-butylphenol), and run # 7, Santocure.
See TBSI (N-t-butyl-2-benzothiazolesulfenimide).
In each case, according to the invention, HVA-2 and Sulfads are also included.

According to Table 14, Runs # 2, # 3 and # 4, Methyl Niclate (nickel dimethyldithiocarbamate) was converted to Sulfads (98% dipentamethylene thiuram tetrasulfide) or Morfax (98% 4-morpholinylyl-2-benzoate). Thiazol disulfide) together with an acceptable combination. MB
PC (2,2'-methylenebis-4-methyl-6-t-butylphenol) or Santocure TBSI (Nt-butyl-2-benzothiazolesulfenimide) is used instead of Methyl Niclate (nickel dimethyldithiocarbamate). And provides an excellent surface with desirable low compression set physical properties. Thus, in the novel peroxide compositions of the present invention, low levels of phenolic antioxidants and sulfenamide class accelerators were found to be HVA-
Works well with 2 and low levels of other sulfur promoters. Based on the teachings of the prior art, it is not obvious that low levels of these compounds will be effective. Examples of prior art formulations using the acrylic co-agent SR-206 (ethylene glycol dimethacrylate) are listed in Table 14, Runs # 14 and # 9, in which a much higher amount of antioxidant, Vanox MBPC ( 99% 2,
2'-methylenebis-4-methyl-6-t-butylphenol) and Vanox
ZMTI (93% Zinc 2-mercapto-tolimidazole) appears to have a poor effect on surface hardening in this formulation, especially for Run # 10, with undesirably higher compression set values.

[0151]

[Table 14]

Example 15 - Fully saturated elastomer (ethylene-octene copolymer). Ethylene-octene (24%) copolymer G81 from Dupont Dow
00 is cured with two levels of dicumyl peroxide in rheometer and in hot air in dilute samples with and without HVA-2-VULTAC5-Butyl Zimate. The extension compound is rubbery, but slightly thermoplastic and not sulfur curable.

In Table 15, runs # 3 and # 4 are only slightly tacky after curing,
This is a major improvement, because most thermoplastic ethylene polymers are very tacky in this test, simply because these polymers melt / soften at these temperatures. Oil may be added to reduce stiffness but make the surface more tacky. Oil can be saved at this low fill level. These samples (Runs # 3 and # 4) were not tacky when cooled to room temperature.

[0154]

[Table 15]

Example 16- Evaluation for the use of different bismaleimide compounds in novel peroxide formulations which are capable of crosslinking elastomers in the presence of air with a tack-free surface . In Table 16, several different bismaleimide compounds were evaluated in the practice of this invention. Unexpectedly, all of these bismaleimide compounds
When tested immediately upon removal from a hot air cure profile at 410 ° F (240 ° C) for 8 minutes, it provided good crosslink efficiency with the addition of a tack free surface. 2 phr of m-phenylene bismaleimide (MBM
) On the same molar basis (taking into account the number of unsaturated functionalities). The structures for these various compounds are listed below:

[Chemical 8]

The rubber compounds used for these experiments are listed below: Rubber compound part Keltan 2506 EPDM (DSM copolymer) 100 N660 carbon black (Huber) 75 Sunpar 2280 (Sun Oil) 15 Peroximon DC40KEP 5 co-agent MBM2phr. Mole equivalent to ^* Vanax A (RT Vanderbilt) 0.2 VULTAC5 (Elf Atochem) 0.7 Durax (RT Vanderbilt) 0.1 ^* Considering the number of unsaturated groups for each co-drug compound Put in.

[0157]

[Table 16]

After completing the MDR2000E testing, the AIR Cure Surf
An ace Tack test was performed. All of the samples were heated in a 410 ° F press oven for 8 minutes. After 8 minutes, the sample was removed and a paper towel was pressed against the hot sample. After cooling, the paper towel was peeled off at a uniform rate and examined for tack. Almost no tack on surface after hot air crosslinked samples cooled to room temperature (except control Run # 1 peroxide cure)
Note that all samples had very similar low tack.
All of the samples also showed their own firing height, which means that each air-cured sample fired internally to some degree. this is,
It depends in part on the low Mooney viscosity of the EPDM used.

Example 17- Further evaluation for the use of different bismaleimide compounds in novel peroxide formulations which are capable of cross-linking elastomers in the presence of air with a tack free surface . 1,2; 1,3 and 1,4 of N, N'-phenylene bismaleimide (ortho,
The (meth, para) isomer was evaluated for use in a novel peroxide formulation that allowed the elastomer to crosslink in the presence of air, resulting in a fully cured tack-free surface. The elastomer used in this example is No
rdel (R) IP EPDM NDR-4640. It is one of the new Dupont Dow metallocene type EPDM elastomers.

Various bismaleimide co-drugs function well and have good adhesion when used with low levels of selected additives according to the present invention, according to Table 17, Runs # 5, # 6 and # 7. Not brought the surface. All of these novel compositions have low levels of sulfur-containing additives (Sulfads, VULTAC 5 and Unads).
) Is used with a bismaleimide co-drug and peroxide.

See Table 17, Runs # 1, # 2, # 3, # 4 and # 8, noting that a poor surface cure was obtained when the separate components of the peroxide formulation were used individually. .
Run # 1 was the peroxide alone, Runs # 2- # 4 were the co-drug and peroxide, and Run # 8 was the peroxide and sulfur promoter blend. In separate cases, the surfaces of these formulations were tacky when hot air cured at 400 ° F cure.

[0162]

[Table 17]

Example 18-Further evaluation of various bismaleimide compounds in the practice of this invention . Table 18 has a non-tacky surface when cured in a hot air oven when four co-drug bismaleimide compounds were used with a peroxide and selected low levels of sulfur promoters in accordance with the practice of the present invention. 5 shows the results of evaluating their effectiveness in providing cured elastomers. In this example, Dupo
nt Dow IP NDR-4640 metallocene EPDM was selected as the elastomer for evaluation work.

The monomeric compound is: 1,1 ′ (3,3-dimethyl-1,1′-
Biphenyl-4,4'-diyl) bismaleimide; N, N '-(1,1'-biphenyl-4,4'-bismaleimide;1,2-bismaleimideethane; and 1,
6-Bismaleimide hexane. In Table 18, they were compared to N, N'-1,3-phenylene bismaleimide or Vanax MBM. We have used our preferred formulation consisting of dicumyl peroxide, Sulfads, VULTAC 5 and Unads to determine that various bismaleimide co-agents give a peroxide control run that results in a highly tacky surface. Table 18, runs # 2 to # 6 were found to provide a good non-sticky surface as compared to # 1.

[Chemical 9]

[0165]

[Table 18]

[0166] Example 19 - 2- (2,4-cyclopentadiene-1-ylidene) -1,3-autonomous Oran, elastomeric good surface curing by crosslinking in a hot-air furnace (nonexistent surface tackiness) Evaluation for use as an additive in novel peroxide formulations , for use in providing good physical properties . Unsaturated sulfur-containing compounds were evaluated in combination with bismaleimide co-drugs and peroxides. 2- (2,4-cyclopentadiene-1-ylidene) -1,3-
The dithiolane compound was converted into N, N'-m-phenylene bismaleimide (HVA-2).
Durax, Vana used in combination with co-drug and dicumyl peroxide
Used in place of the blend of xA and VULTAC 5. The data in Table 19 show that this unique formulation provided efficient cross-linking with a good tack-free surface upon hot air curing at 410 ° F for 8 minutes.

[Chemical 10]

In addition to good cross-linking performance in the presence of air, thereby overcoming air (oxygen) inhibition, the final cross-linked elastomer was obtained after heat aging the cross-linked EPDM at 150 ° C. for 70 hours. It has been found to have excellent ultimate physical properties based on the desired low percent compression set.

[0168]

[Table 19]

[0169] Example 20 - polysulfide as an additive in combination with the selected halogenated polymer or silicone rubber, peroxide, used in conjunction with sulfur accelerators and bismaleimide co pharmacists, tacky at EPDM formulation as highly stretched to generate a nonexistent surface of. A blend of Nordel IP 4520 (Dupont Dow elastomer) with an equal weight of carbon black and high levels of oil would be difficult to cure with conventional peroxides, which is a sulfur cured hose compound formulation. It is a typical thing. Highly stretched EPDM formulations where the carbon black and / or oil levels are about the same as the EPDM loading represent formulations that are difficult to cure sufficiently with organic peroxides. When curing highly filled EPDM in the presence of air, if it is a rubber, the peroxide radicals will act on the oil and carbon black,
So it is very difficult to obtain a good level of cure in the presence of air and maintain a tack free surface.

We have also used our novel blend of sulfur promoters and bismaleimides to reduce the amount of (FA) polysulfide polymer and (SE6160).
) Silicone rubber was incorporated as a novel additive for use in our invention. The present inventors have found that polysulfide polymers and silicone rubber or chlorinated polyethylene or hypalon (chlorosulfonated polyethylene),
It has been found that blending a peroxide, a bismaleimide co-agent and low levels of a selected sulfur promoter will produce a suitably tack free cured surface in the presence of air. As such, the novel blend provides a means for curing these highly stretched EPDM formulations that are typically cured by sulfur vulcanization. It is noted that the various sulfur vulcanization systems used in the art are not sensitive to higher concentrations of oil and carbon black and are able to fully cure highly stretched rubber compounds.

From this it follows that the present inventors are polymer masterbatches of peroxides, selected sulfur promoters, bismaleimide co-agents, polysulfides, with chlorinated polyethylene and / or chlorosulfonated polyethylene as further additives. The fact that the incorporated product could be prepared is included as part of the invention of the present inventors.

It is noted that the use of silicone rubber without the polysulfide polymer produces a reasonably tacky polymer. The use of fluoroelastomers in combination with polysulfides as an additive in our invention does not produce a suitable surface.

[0173]

[Table 20]

Example 21 -In this example we show more data for curing highly filled EPDM formulations " difficult to cure by peroxide ". We use more carbon black (180 parts total) in this particular formulation than EPDM rubber (used as 100 parts total).
Using a novel blend of peroxide, MBM and a selected sulfur promoter (listed as Blend 1), when cross-linked in the presence of air, compared to the aim peroxide (Run 1) at a lower overall hardener concentration. Provides a good surface (Run 2). Again, this is a highly filled EPDM formulation that is very difficult to cure with organic peroxides. Those skilled in the art will not consider using such formulations with organic peroxides and will simply use sulfur vulcanization cure systems.

Upon crosslinking in the presence of hot air, a small amount of chlorosulfonated polyethylene (
Further improvements in surface hardening were achieved when (Hypalon-Dupont Dow) was used as a novel additive to be used in the practice of our invention (Run 3). Blend of Polysulfide and Hypalon (Run 4)
When used as a novel polymer additive in the practice of the inventors,
Further improvement in surface hardening was observed.

[0176]

[Table 21]

[0177] Example 22 - In this example, the present inventors have elastomer a several novel useful in the development of peroxide formulations for crosslinking in the presence of hot air chemical additive pressurizing thereof and polymer additives The thing is illustrated.

In particular, these are: Vanax 6H (N-cyclohexyl-N ′.
-Phenyl-p-phenylenediamine) CAS 101-87-1, diene-based polymers; antiozonants for polysulphide (PTE) and silicone rubber (VMQ). Vanax 6H (RT Vanderbilt)

[Chemical 11]

The inventors have shown that antiozonants act as alternatives to sulfur-containing compounds in the practice of the invention. The invention contemplates that such antiozonants and those substitutions of similar structures are fully equivalent to other compounds included within the definition of Compound (B). In addition, polysulfide (PTE)
Also serves this same purpose.

Finally, the unexpected blending of the two polymers PTE and VMQ as polymer additives makes it possible to produce a tack-free surface with peroxides in the presence of hot air. Note that no bismaleimide and sulfur compounds or antiozonant additives were used.

[0181]

[Table 22]

Example 23-Examples Using Various Other Dialkyl-Type Peroxides In this example, we have prepared a metallocene-based EPDM (Nordel IP).
4640) is crosslinked using different organic peroxides. It is noted that in each case the peroxide could not result in a tack free surface when the EPDM elastomer formulation was crosslinked in the presence of hot air without the use of various additives. The peroxides listed in Table 23 are: Peroxide Chemical Name Lup 101 2,5-Dimethyl-2,5-di (t-butylperoxy) hexan MTBPP 4-Methyl-4- (t-butylperoxy)- 2-Pentanone Luperx F / R Di (t-butylperoxy) diisopropylbenzene DAPDIB Di (t-amylperoxy) diisopropylbenzene

This example illustrates that in addition to the most commonly used dialkyl peroxide, dicumyl peroxide, which was extensively evaluated in the previous examples, other dialkyl peroxides can be used in the practice of the present invention. I'll give it to you.

[0184]

[Table 23]

One of ordinary skill in the art may also formulate the compositions of the invention as a masterbatch for convenience in handling and compounding into polymers in the presence of molecular oxygen. Let's recognize. Typical masterbatch carriers include, for example, microcrystalline wax, polycaprolactone, ethylene propylene diene monomer polymer (EPDM), ethylene propylene monomer polymer (EPM), ethylene vinyl alcohol polymer (EVA), polyethylene (
PE) or a mixture thereof.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/3415 C08K 5/3415 5/40 5/40 5/44 5/44 C08L 23/28 C08L 23 / 28 23/34 23/34 81/04 81/04 101/00 101/00 (72) Inventor Leonard Henry Paris United States 19335 Pennsylvania, Eagle, Redtail Circle 204 (72) Inventor Gary James Gallo United States 03825 New Hampshire, Barrington, Oak Hill Road 48 F Term (Reference) 4F070 AA04 AA16 AA60 AC46 AC50 AC56 AC57 AC66 AC84 AC94 AE08 AE16 AE28 FA03 FA17 FB04 FB05 FB06 4J002 AE033 BB033 BB151 FDFD 20949 FD49 FD049 FD049 EK78 EV048 EK078EU0 EF048E048E048E048E048E048E048E048E048E048E048E048E048E048E048E048E048E0480E048E0480

Claims (27)

[Claims] 1. A composition comprising: a) at least one compound (A) selected from the group consisting of silicone elastomers and compounds having formula (I): Wherein n is 1 or 2, R is divalent or trivalent and has about 2 to 16 carbon atoms.
A group having an acyclic aliphatic group having 5 to 20 carbon atoms, a cycloaliphatic group having from about 5 to 20 carbon atoms, an aromatic group having from about 6 to 18 carbon atoms and an alkyl aromatic group having from about 7 to 24 carbon atoms. Divalent or trivalent groups may contain one or more heteroatoms selected from O, N and S instead of one carbon atom or a plurality of carbon atoms, each R atom ₁ is the same and is hydrogen or an alkyl group having 1 to 18 carbon atoms: and b) accelerating the sulfur vulcanization of a polymer which can be crosslinked by a p-phenylenediamine based antiozonant and sulfur. At least one compound (B) selected from the group consisting of sulfur-containing organic compounds selected from the group consisting of sulfur-containing organic compounds, polysulfide polymers, and mixtures of said sulfur-containing compounds. 2. A composition according to claim 1, additionally containing a free radical initiator selected from the group consisting of organic peroxides and azo initiators. 3. A composition comprising the composition of claim 2 and a polymer curable by a free radical initiator. 4. The composition of claim 3 is molded into a shaped article, which then initiates the decomposition of the free radical initiator in the presence of molecular oxygen and thereby is substantially tack free. A method comprising applying a temperature sufficient to obtain a cured shaped article. 5. A composition formed by mixing compound (A) and compound (B) as claimed in claim 1. 6. A composition formed by mixing the compounds (A) and (B) as defined in claim 1 with an organic peroxide in any order. 7. A composition according to claim 1, wherein compound (A) is selected from bismaleimides and compound (B) is selected from sulfur promoters. 8. The compound (A) is selected from biscitraconimide and
The composition of claim 1 wherein B) is selected from sulfur promoters. 9. A composition according to claim 1, wherein compound (A) is selected from bismaleimides and compound (B) is selected from polysulfide polymers. 10. A composition according to claim 1, wherein compound (A) is selected from biscitraconimides and compound (B) is selected from polysulfide polymers. 11. A composition according to claim 1, wherein compound (A) is selected from silicone elastomers and compound (B) is selected from polysulfide polymers. 12. The composition of claim 1 which also comprises a compound selected from the group consisting of chlorinated polyethylene and chlorosulfonated polyethylene. 13. The free radical initiator selected from organic peroxides.
The composition as described. 14. A tack-free cured polymer that is cured by free radicals generated by decomposition of a free radical initiator in the composition of claim 3 in the presence of molecular oxygen. 15. Claim to claim in producing a tack-free cured polymer which is cured by free radicals generated by the decomposition of free radical initiators contained therein in the presence of molecular oxygen. A method comprising formulating the composition of claim 2 and applying sufficient heat energy to decompose the free radical initiator thus introduced into the polymer. 16. A free radical initiator can be cross-linked in the preparation of a curable composition which can be cured by a free radical initiator in the presence of molecular oxygen to give a tack free surface. Claim 2 to polymer
A method comprising formulating the described composition. 17. A free radical initiator can be cross-linked in the preparation of a curable composition which can be cured by a free radical initiator in the presence of molecular oxygen to give a tack free surface. Claim 1 to polymer
A method comprising formulating the described composition in the presence of a free radical initiator. 18. The compound (A) is selected from one or more bismaleimides and the compound (B) is selected from dialkylthiuram tetrasulfide, diarylthiuram tetrasulfide, alkylphenol disulfide, tetraalkylthiuram monosulfide, tetraarylthiuram monosulfide and The composition of claim 1 selected from the group consisting of these mixtures. 19. A composition according to claim 2 wherein the free radical initiator is selected from dialkyl peroxides or peroxyketals. 20. The composition according to claim 18, additionally containing a free radical initiator selected from dialkyl peroxides or peroxyketals. 21. The compound (A) is selected from one or more bismaleimides, and the compound (B) is selected from 4,4-dithiomorpholine, acyclic alkyl-2-benzothiazole sulfenamide, cyclic alkyl-2. A composition according to claim 1 selected from the group consisting of: benzothiazole sulfenamide, aryl-2-benzothiazole sulfenamide, alkylphenol disulfide and mixtures thereof. 22. The composition according to claim 21, additionally containing a free radical initiator selected from dialkyl peroxides or peroxyketals. 23. The composition of claim 2 comprising dicumyl peroxide, N, N-phenylene bismaleimide, 4,4-dithiomorpholine, alkylphenol disulfide and N-cyclohexyl-2-benzothiazole sulfenamide. 24. The composition of claim 2 comprising dicumyl peroxide, N, N-phenylene bismaleimide, dipentamethylene thiuram tetrasulfide, alkylphenol disulfide and tetramethyl thiuram monosulfide. 25. The composition of claim 2 comprising dicumyl peroxide, N, N-phenylene bismaleimide, dipentamethylene thiuram tetrasulfide, alkylphenol disulfide and Nt-butyl-benzothiazole-2-sulfenimide. . 26. Microcrystalline wax, polycaprolactone, E
The composition of claim 1 formulated as a masterbatch on a carrier selected from the group consisting of PDM, EPM, EVA, PE and mixtures thereof. 27. Microcrystalline wax, polycaprolactone, E
The composition of claim 2 formulated as a masterbatch on a carrier selected from PDM, EPM, EVA, PE and mixtures thereof.