JPS5919146B2 - Moisture-curable polymer composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new method for producing moisture curable polymers and in particular to moisture curable butyl rubber.

This moisture-curable elastomer is produced by reacting a polymer having a conjugated olefin unsaturated bond with a cyclic unsaturated acid anhydride, and then converting the reaction product into a polyvalent metal compound (however, the polyvalent metal compound may be an oxide, hydroxide or alkoxide) and, in some cases, a basic hydrolysis catalyst.
It is known that moisture-curable EPDs (2) and (unsaturated EPDWs) can be prepared by grafting selected silane monomer compounds onto the backbone.

This method provides graft copolymers or adducts to the backbone of the base polymer. US Patent Nos. 3 and 5
See No. 03,943. It is also known that the reaction of butyl rubber containing a conjugated olefinic unsaturated bond with maleic anhydride produces a bicyclic adduct as shown below. Child--yo-0≦!゛! ■----1--\♂Then, this adduct can be hydrolyzed to produce a dicarboxylic acid.

It can also be reacted with metal salts or amines to produce ionomers. U.S. Patent No. 3,646,16
See issue 6. It has surprisingly been discovered that moisture-curable butyl rubbers can be made from butyl rubbers containing conjugated olefin unsaturation without the need for modification with silanes. The products of this invention are useful in coatings, linings, caulks, sealants, and elastomeric articles (eg, hoses, sheeting materials, insulated wire, etc.) that are cured in steam autoclaves in a conventional manner.

Moisture-curable butyl rubber is produced by reacting butyl rubber containing conjugated olefin unsaturated bonds (which can be abbreviated as "CDB") with maleic anhydride in an anhydrous state, and converting the reaction product into a polyvalent metal compound and, in some cases, can be produced by blending with a basic hydrolysis catalyst.

In particular, when halogenated butyl rubber is dehydrohalogenated, conjugated double bonds are generated. This dehydrohalogenated product is then reacted with maleic anhydride to produce a butyl rubber grafted with cyclic anhydride groups. The polymer thus produced is blended with an oxide, hydroxide or alkoxide of a polyvalent metal if a basic hydrolysis catalyst is not used, or with a polyvalent metal if a basic hydrolysis catalyst is used. It can be made moisture curable by blending it with an oxide or hydroxide. Other feedstock components that can alter the cure rate and/or properties of the uncrosslinked and crosslinked materials may also be used. As used herein and in the claims, the term "butyl rubber" refers to isoolefins having from about 4 to 7 carbon atoms, such as isobutylene.
0-99.5 weight? , and a conjugated multiolefin having about 4 to 14 carbon atoms, such as isoprene, about 30 to 0.5% by weight? It encompasses copolymers prepared from polymerization reaction mixtures containing

The resulting copolymer contains 85-99.5% by weight isoolefin and 0.5-15% multiolefin.
Butyl rubber generally has a price of about 20,000 to 500,000
1. As a method for producing butyl rubber having a monomolecular weight of preferably about 25,000 to 400,000, especially about 100,000 to 400,000, and a Wiss iodine number of about 0.5 to 50, preferably 1 to 15. See US Pat. No. 2,356,128.

Recently, semi-liquid solid butyl rubbers with number average molecular weights of 5,000 to 20,000 f1/mol have been produced. For the purposes of the present invention, approximately 0.5 to 6% as a high molecular weight elastomer.
, preferably 0.5-4%, e.g. 2% multi-olefin, and for low molecular weight elastomers about 3-4%, e.g.
Containing 4% multi-olefin, the semi-liquid elastomer preferably has a number average molecular weight in the range of 5,000 to 20,0009/mole.

The first step in the production of the butyl rubber ionomer involves dehydrohalogenation of the halogenated butyl rubber.

Halogenated butyl rubbers are commercially available, and include about 2 to 25% by weight of butyl rubber in a substantially inert C5 to C8 hydrocarbon solvent such as pentane, hexane, heptane, etc. It can be produced by halogenation by contacting with halogen gas for minutes. The copolymers contain up to one halogen atom (and may be more, especially in the case of bromine) per double bond originally present in the copolymer. The method for producing halogenated butyl rubber is a known technique. For example, U.S. Pat.
See No. 99,644. The present invention is not intended to be limited by the method of halogenating butyl rubber. Both chlorinated butyl rubber and brominated butyl rubber are suitable for producing butyl rubber containing conjugated olefin unsaturated bonds. As an example of halogenated butyl rubber, Enjay
) Butyl HTlO-68 (chlorinated butyl rubber with 1.8 moles of unsaturation and a viscosity average molecular weight of about 450,000 before halogenation).

However, for the present invention, the starting material high molecular weight butyl rubber is about 0.5-6%, preferably 0.5-3%;
For example, it is preferred to have about 2% diolefin.
Conventional high molecular weight butyl rubbers generally have a molecular weight of about 25,000 to 500,000, preferably about 80,000
00-25,0,0001 especially about 100,000-22
It has a number average molecular weight of 5,000 and a Wiss iodine number of about 0.5 to 50, preferably 1 to 15.

Recently, the number average molecular weight is 5,000 to 20,000 and the number of unsaturated bonds is 2 to 10 moles? of low molecular weight polymers were produced. Furthermore, about 5 to 40 weight recently? A butyl-type polymer having 2 unsaturated bonds was produced.

See, eg, US Pat. No. 3,808,177. Polymers useful herein include about 70-99.5% by weight isoolefins having about 4-7 carbon atoms and about 0.5-30% by weight isoolefins having about 4-7 carbon atoms.
% by weight of a copolymer of conjugated diolefins. Preferred diolefins are isoprene, piperylene, cyclopentadiene or mixtures thereof. If the polymer contains 1% or more by weight of diolefin, it is not necessary to halogenate all unsaturated bonds before carrying out the dehydrohalogenation step of the present invention. If desired, the unsaturation sites of the polymer may be completely halogenated. The methods of halogenating or dehydrohalogenating polymers with less than 15% unsaturation are applicable to more highly unsaturated polymers. In a preferred embodiment, the majority of the unsaturated bonds in the copolymers of the invention are of the conjugated diene type.

However, if the copolymer initially contains 1 mole % or more of diolefin, it is not necessary to completely halogenate all unsaturation positions. In such polymers, it is preferred that about 1-3% by weight of the unsaturated bonds be halogenated. After dehydrohalogenation, the polymers produced in this manner contain about 2 to 30% unsaturated bonds due to initially bonded diolefins that are not of the conjugated diene type. Approximately 0.5 to 3 weight of polymer? When containing a diolefin, it is preferred to halogenate substantially all of the unsaturated bonds, followed by dehydrohalogenation to produce a copolymer in which most of the unsaturated bonds are of the conjugated olefin type. Dehydrohalogenation is a known chemical reaction, and commonly used reagents are, for example, those of Lewis F.
uisF. ) and MaryFie
``ReagentsfOrOrganicSynthesis'' by Ser)
p. 1308 of John Willy & Sons, Inc., New York 1967).

Among these are, for example, 5-butylamine, N,N-dimethylformamide, calcium carbonate, potassium t-butoxy and sodium iodide in 1,2-dimethoxyethane. This method and reagents have been used for low molecular weight substances.

In that case, the substance to be dehydrohalogenated and the dehydrohalogenating agent are brought into uniform contact at a high concentration. In this case, the compounds and reagents can be dissolved using polar solvents such as dimethyl sulfoxide, ethanol, diethyl ether, and the like. For high molecular weight polymers that contain only small amounts of halogen, are not soluble in highly compatible solvents, and where the concentration of halogen-containing polymer is limited by the high viscosity of the polymer solution, the compositions of the present invention This dehydrohalogenation method is not suitable for producing . Furthermore, even if the dehydrohalogenating agent is soluble in the hydrocarbon, undesirable side reactions occur and interfere with the formation of the products of the present invention. Dehydrohalogenation yields butyl rubber containing conjugated double bonds.

This product will hereinafter be referred to as CDB. Without wishing to be bound by any reaction theory, it is believed that a typical structure of halogenated butyl rubber (mainly isoprene) is a mixture of the following formula: and (where n+l and m each represent the number of isoolefins and conjugated olefins bonded to the initial butyl rubber polymer, and X represents halogen.

). By dehydrohalogenation, for example, the following formula: and A conjugated double bond like this is generated.

Next, these conjugated double bonds are reacted with an unsaturated acid anhydride to produce modified butyl rubber.

An example of an unsaturated compound that can be used is maleic anhydride. The present invention is not limited to butyl rubber, but can be applied to any elastomer into which conjugated olefin unsaturated bonds can be introduced.

Such elastomers contain conjugated olefin unsaturated particles.
PDM, and its manufacturing method is described in U.S. Patent No. 3,681,30.
It is stated in No. 9.

Polymeric materials having attached cyclic anhydride groups are also suitable for use in the present invention.

The concentration of said groups is about 0.4-10 mol%. Such materials are either produced by copolymerization as described above, or by thermal reaction (20'C) (i.e., the so-called "-Ene") addition reaction of a polymer with olefinic unsaturated bonds with maleic anhydride; K. Alder
, F. Pzscher and A. Schmitz, Berichte Deutsche
chChem. Gesellshaft), 1943,
76, 27) can be applied regardless of whether it is manufactured by

Elastomers containing conjugated olefinic unsaturated bonds with the highly reactive dienophilic acid anhydride
Because the reaction with conjugated olefin elastomers ("conjugated olefin elastomers") is a Dales-Alda reaction, the reaction occurs spontaneously and requires no catalyst or excessive heating. However, in this Dales-Alda reaction, HCl and Al
It is also known that some reactions can be accelerated by acidic substances such as Cl3 in the same way as heating. Finally, the cyclic unsaturated acid anhydride can be grafted onto the conjugated olefin elastomer in the same reactor after dehydrohalogenation. This modification step is preferably carried out at a temperature significantly below 200C, more preferably between 250C and about 150C. Grafting of an unsaturated acid anhydride onto a conjugated olefin elastomer also
It can also be carried out by dissolving B in an inert solvent and then reacting this solution with a loamy unsaturated acid anhydride at a temperature of about 25 DEG to 150 DEG C. for the time required for the reaction to be complete. The adduct can also be prepared by mixing bulk CDB and maleic anhydride in conventional mixing equipment.

A typical product of the reaction of an acyclic conjugated olefin with a loamy unsaturated acid anhydride is:
is a hydrocarbon group (eg, alkyl, aralkyl, alkenyl) or hydrogen.

). If the most preferred reaction between CDB and maleic anhydride occurs, the following products are obtained.

Although there is no intention to be bound by the following description, it is believed that the chemical reaction of the present invention proceeds through the following series of steps.

Production of modified elastomers Hydrolysis of modified elastomers (However, M is a divalent metal).

Although the reaction scheme above suggests a reaction between MO and an aliphatic carboxylic acid, it is likely that this reaction requires the conversion of MO to M(0H)2 at least at its surface.

In fact, in other experiments it was observed that the reaction between CaO and naphthenic acid did not easily occur without the addition of some water. This is a possible intermediate reaction MO+H2O-? M (0H)
2 suggests that MO changes to M(0H)2 and the product H2O changes to 2H20 in equation (3).
Thus, in a sense, when using very pure MO it is necessary to hydrolyze the oxide, making the crosslinking reaction more sensitive to water. Also, M(0H
) 2 may open the ring of the cyclic acid anhydride. This first step is shown below. υυ In this case, the sensitivity of the crosslinking reaction depends on the hydrolysis of the MO rather than on the hydrolysis of the acid anhydride.

However, as previously stated, the invention is not bound to any particular method of operation. In reaction (2), one molecule of water is required to hydrolyze each anhydride group.

Reaction (3) suggests that one molecule of water is produced for each crosslink by the reaction of a pair of carboxylic acid groups in the hydrolyzed material with the oxide of the divalent metal. This produced water molecule is sufficient to hydrolyze one molecule of acid anhydride. In this way, self-support
ning) system is obtained. In the case of polyvalent metal hydroxides such as Zn(0H)2, two molecules of water are produced from each crosslink formed. Obviously, increasing the temperature or immersion in water or steam increases the crosslinking rate. Furthermore, the produced carboxylic acid salt has a certain degree of hygroscopicity, and due to the production of water during the crosslinking reaction, even those with a large cross-sectional area can be cured at an appropriate speed despite the butyl molecule's inherent incompatibility with water vapor. You will be able to do it.

A desirable feature of this system is that exposed surfaces crosslink first. In this way, the surface crosslinks or "dries" relatively quickly, even if it takes a considerable amount of time to crosslink to the interior. Crosslinking in the presence of moisture can also be achieved by using alkoxides of polyvalent metals such as aluminum isopropoxide, aluminum budoxide, titanium propoxide, etc. instead of simple metal oxides.

They can also be used with oxides or hydroxides of polyvalent metals. Solvents useful in this invention are substantially inert hydrocarbon and chlorinated solvents. Examples of substantially inert hydrocarbon solvents that may be used in the present invention include C, to C8 solvents such as pentane, hexane, heptane, cyclohexane, benzene, toluene, mineral spirits, and mixtures thereof. . Examples of substantially inert chlorinated solvents that may be used in the present invention include chloroform, carbon tetrachloride, dichloromethane, and perchloroethylene. Basic hydrolysis catalysts suitable for the present invention include triethylamine, tributylamine, 2,4,6,1-tris(dimethylamine)phenol, 1-azo-3,3,
7,7-tetramethylbicyclo(3,3,0)octane (hereinafter referred to as "Arkam"), N,N-
Contains catalysts such as tertiary amines such as diethylaniline and other amines that are soluble in the system in the amounts used.

The amine should be selected with consideration to its basic strength based on its structural characteristics. Thus, we choose pyridine as a mild catalyst and alkam as a strong catalyst. Polyvalent metal oxides, hydroxides and alkoxides suitable for the present invention include oxides, hydroxides and alkoxides of metals selected from Groups A, B, LA and B of the Periodic Table.
"Handbook of Chemistry and Physics"
ndPhysics), Chemical Lab Publishers, 47
vol., page B-3).

Suitable divalent metal ions include, for example, Be to Mg28,
Ca2+, Sr2Ba2+, Cd2+, Hg2+, Pb
2+ and Zn2+. Suitable trivalent and tetravalent metal ions are Al3+ and Ti4+. Both of the former can be produced in alkoxide form, but are no longer effective in oxide form. In general, polyvalent metals whose hydroxides are basic or amphoteric and can react with carboxylic acids to form metal salts or alkoxides can be used.

In view of cost, toxicity, difficulty in handling, coloration, etc., preferred alkoxides are those of aluminum, while preferred metal oxides are oxides of magnesium, calcium and zinc. Alkoxides are known to be more basic than the corresponding hydroxides. Therefore, it is generally not used when using a basic hydrolysis catalyst in the present invention. Example 1 2759 conjugated diene butyl rubber (CDB2358-38-2 containing about 1.2 mole % conjugated diene and about 0.15 mole % allyl ester) was dissolved in 4j hexane and heated in a reciprocating shaker for 24 The mixture was mixed for a period of time to produce cement.

Next, 6.59 g of maleic anhydride was added and the mixture was left on a shaker for an additional day at about 100'F (38°C) to complete the reaction between maleic anhydride and CDB. Next, a paste of rubber-grade ZnO was added to a ZnO paste of about 49
It was produced by grinding and mixing nO and 19 Flexon 580 (extender oil) using a spatiera. 25
Aliquots of TfLt rubber cement were placed in 1 oz ointment containers and left for 40 days.

No evidence of crosslinking was observed even on day 40.

Example 2 Following the procedure of Example 1, an aliquot of .25 d of rubber cement was placed in a 1 oz. ointment container, into which was added approximately 1 drop of water and 1 drop of Alcum (described above).

The mixture was stirred and left for 40 days. No evidence of crosslinking was observed even on day 40.

Example 3 Following the method of Example 1, 25WLI! Approximately 0.19 of the zinc oxide paste was added into an ointment container containing an aliquot of .

Again, the mixture was stirred to disperse the zinc oxide and left for 40 days. Even on day 40, no evidence of crosslinking was seen.

Example 4 An aliquot of cement of 25T1L1 and about 0.1 f of the zinc oxide paste prepared in Example 1! was placed in an ointment container with one drop of pyridine (a tertiary amine).

Again, the mixture was stirred and allowed to stand. After 20 days, gelation of the contents in the ointment container occurred.

This indicates that crosslinking occurred as a result of the presence of extraneous water. Example 5 2571LI! An aliquot of ., of cement and about 0.19 g of the zinc oxide paste prepared in Example 1 was placed in an ointment container with one drop of water.

The mixture was stirred again and allowed to stand. Gelation occurred in only 4 days. This indicates that it is a moisture curing system. Example 6
25TnI! , of cement and about 0.19 g of the zinc oxide paste prepared in Example 1 were placed in an ointment container along with 1 drop of water and 1 drop of alkam.

The mixture was stirred again and allowed to stand. Gelation occurred within 2 hours.

This indicates that the introduction of a strongly basic hydrolysis catalyst generally accelerates moisture curing. Example 7 A 25d aliquot of cement and about 0.1f1 of the zinc oxide paste prepared in Example 1 were placed in an ointment container;
Added 1 drop of water and 1 drop of pyridine into it.

The mixture was stirred and allowed to stand. Gelation was observed after about 6 hours. This indicates that pyridine (a weakly basic hydrolysis catalyst) does not promote moisture curing as much as alkam (a strongly basic hydrolysis catalyst). Although the foregoing examples illustrate the invention in a very simple manner, many ways are possible to control the rate of ionomeric crosslinking.

For example, it is possible to have products that remain uncrosslinked for a very long time, but which undergo crosslinking relatively rapidly.
This can be done, for example, by adding to the catalyzed compound a non-toxic desiccant or a substance that reacts quantitatively and rapidly with moisture. Such substances include, for example, CasO4 or orthoformate esters such as (where R is an alkyl group), for each example.

The latter substances readily react with water as follows. ethyl or ethyl), the resulting ester and alcohol will easily evaporate from the system, or at worst the alcohol will react with the cyclic acid anhydride to form a half ester (each ionomer will have one carboxylic acid group remaining at a position capable of crosslinking). ).

That is, as described above, dry calcium oxide does not easily react with carboxylic acid, but the addition of water facilitates the reaction.

Calcium oxide is also a good desiccant (forming Ca(0H)2 when reacted with water), so when it is used, a single species is responsible for slowing down the reaction and participating in the subsequent crosslinking reaction. You will be doing both. In this way, the system depends on the amount of catalyst used and the base strength, the hygroscopicity of the system (e.g. certain fillers, e.g. acidic clays readily absorb water).
, the presence of a desiccant or substance that reacts with water more rapidly than the acid anhydride (or metal oxide or alkoxide) hydrolyzes, etc.

Examples 8-10 The following raw material components were used.

The polymer, black oil and CaO were mixed on a rubber mill in a conventional manner.

This masterbatch and maleic anhydride were dissolved in toluene and shaken for 10 days. T-amine was added to the cement, which was shaken overnight and then poured into glass plate molds. Toluene was evaporated at room temperature. After 24 hours, the resulting film was tack-free.

After 6 days, its physical properties were tested.

The physical properties of the 0.020 inch film exposed on one side are shown in the following table.

The polymer, black oil and metal compounds were mixed on a rubber mill in a conventional manner.

Dissolve this mixture and maleic anhydride in toluene,
Cement was produced by shaking for days. Amine was added to a portion of the cement, which was shaken overnight and then poured into gas plate molds. The resulting film became tack-free within 24 hours. Its physical properties were tested after 6 days as shown below. Embodiments of the present invention are shown below.

(1) The moisture-curable polymer composition according to claim 1, wherein the polymer containing randomly distributed conjugated olefin unsaturated bonds is CDB.

(2) The moisture-curable polymer composition according to claim 1 or (1) above, wherein the cyclic unsaturated acid anhydride is maleic anhydride. (3) The polyvalent metal compound is a group a of the periodic table.
and metal 1 selected from the group consisting of group b metals. Curable polymer composition. (4) Claim 1 and the above (1) characterized by containing a basic hydrolysis catalyst.
The moisture-curable polymer composition according to (3).

(5) The polymer composition according to (4) above, wherein the basic hydrolysis catalyst is a tertiary amine.

(6) The polymer composition according to claim 1 and items (1) to (5) above, which has an average molecular weight of about 5,000 to 250,000.

(7) Claim 2 and (22) A cured elastomer produced by curing a product obtained by the method described above. (8)
A cured elastomer produced by the method of (23) to (27). (9) Claim 1 and above (1) -
A cured elastomer produced by curing the elastomer composition described in (6).

(c) A method of curing an elastomer substantially as described above.

AO A cured elastomer substantially as described above. (12) The method according to claim 2, wherein the polymer containing randomly distributed conjugated olefin unsaturated bonds is CDB.

(113) Claim 2 or the above (113) characterized in that the cyclic unsaturated acid anhydride is maleic anhydride.
).

U4) The polyvalent metal compound is an oxide or hydroxide of a metal selected from the group consisting of metals of groups A and B, or an alkoxide of a metal selected from the group consisting of metals of groups A and Vb. The method according to claim 2 and J2) to U3), characterized in that:

U5) Claim 2 and (12) to (self) above, characterized in that the polyvalent metal compound is an oxide or hydroxide when a basic hydrolysis catalyst is used at the same time. Method described.

(O) The method according to the above (O), wherein the polyvalent metal compound is an oxide or hydroxide of a metal selected from the group consisting of metals in Groups A and B of the Periodic Table.

(5) The method according to claim 2 and items 13) to 13), wherein the polymer has a number average molecular weight of 5,000 to 250,000.

(auto) Claim 2, characterized in that the reaction is carried out at a temperature of 25°C to 150°C, and (12) to (
The method described in 6). Claim 2, characterized in that up to 1 mole of cyclic unsaturated acid anhydride is used per mole of conjugated olefin units present in the polymer.
2. The method described in Section 1 and Items 1 to 1 above.

(to) The method according to claim 2 and items (1) to (1) above, wherein the polyvalent metal compound is ZnO.

Q1) The substantially inert solvent is pentane, hexane,
C5 selected from heptane, cyclohexane, mineral spirits, benzene, toluene and one combination thereof
The method according to claim 2 and A2) to (20) above, wherein the hydrocarbon is a C8 hydrocarbon.

(1) The substantially inert solvent is a chlorinated solvent selected from the group consisting of chloroform, carbon tetrachloride, dichloromethane, and perchloroethylene. The method described in subsections) to (20).

(Support) A method of moisture curing an elastomer containing randomly distributed conjugated olefin unsaturated bonds,
a) the elastomer containing randomly distributed conjugated olefin unsaturated bonds is reacted with a cyclic unsaturated acid anhydride, and (b) the reaction product of (a) contains a polyvalent oxide or hydroxide. A method comprising blending metal compounds and (c) reacting the blend of (b) with water.

(b) The method described in (b) above, wherein the elastomer containing randomly distributed conjugated olefin unsaturated bonds is CDB.

(auto) The method described in (auto) above, wherein the cyclic unsaturated acid anhydride is maleic anhydride.

(to) The above (to), wherein the polyvalent metal compound is an oxide or hydroxide of a metal selected from the group consisting of metals in groups a and b of the periodic table. Method described.

(auto) The method described in (i) to (i) above, characterized in that it contains a basic hydrolysis catalyst.

Claims (1)

[Scope of Claims] 1 (a) an adduct obtained by reacting a polymer containing randomly distributed conjugated olefin unsaturated bonds with a cyclic unsaturated acid anhydride, and (b) an oxide, water A moisture-curable elastomeric polymer composition containing a polyvalent metal compound that is an oxide or an alkoxide. 2. A polymer containing randomly distributed conjugated olefin unsaturated bonds is reacted with a cyclic unsaturated acid anhydride in an anhydrous state, and then the reaction product is a polyvalent metal compound (however, the polyvalent metal compound is an oxide). , a hydroxide or an alkoxide).