NO853930L - MASSES THAT CAN BE HEATED, AND PROCEDURE FOR PROMOTING COLDS THAT ARE COLDED. - Google Patents

Abstract

1. A composition composed of a binder, an additive which catalyses the crosslinking, and optionally further customary additives, and having the following features : a.1 the binder is composed of 10 to 90 % by weight of the binder I and 90 to 10 % by weight of the binder II ; a.2 the binder I is a polymer carrying primary or secondary hydroxyl groups and having a hydroxyl number of from 10 to 150 [mg of KOH/g] and having Mn 1,000 to 8,000 ; a.3 the binder II is a polymer carrying lateral succinic anhydride groups and having an acid number of from 20 to 250 [mg of KOH/g] and having Mn 1,000 to 8,000 ; a.4 the functionalized polymers in a.2 and a.3 are based on homopolymers of 1,3-butadiene or copolymers composed of >= 70 % by weight of 1,3-butadiene and =< 30 % by weight of other copolymerizable 1,3-(cyclo(dienes and/or copolymerizable alphaolefins, which may be modified by isomerization, hydrogenation or cyclization ; b the additive which catalyses the crosslinking is an organonitrogen base which is not acylated under the crosslinking conditions and is selected from the group comprising the sterically hindered primary and secondary amines, the tertiary amines with the exception of triethylamine, and the N-alkyl imidazoles.

Description

The invention relates to masses which can be heat-crosslinked, more specifically masses as stated in the introduction to claim 1,

and a method for producing masses which are cold-crosslinked, according to the introduction to claim 3.

The pulps are of interest for exceptionally versatile applications, e.g. such as joint sealing compounds, adhesives, putty, putty compounds and vibration damping compounds.

Masses which are hot-crosslinked and masses which are cold-crosslinked, and which consist of a polymer based on 1,3-butadiene with a number-average relative molecular mass (Mn) of

5,000 - 10,000 as binder, the polymer bearing primary and/or secondary hydroxyl groups, an effective amount of one diisocyanate, e.g. Toluylene diisocyanate and diphenylmethane diisocyanate, as a cross-linking agent as well as common additives, are known.

These masses have the disadvantage that the cross-linking agent

is not inconceivable from an occupational hygiene point of view and the handling of this agent therefore requires special measures to protect the staff.

There has therefore been no shortage of efforts to replace the diisocyanates with cross-linking agents that are safe from occupational hygiene.

In US-A 3,624,014 it is e.g. proposed to cross-link the binder by transesterification of a tetraalkylsilicate with the aid of a tin(II) octoate catalyst.

It has also already been suggested as a binder

to use a polymer that carries carboxyl end groups, and which is obtained by reacting a polymer with hydroxyl end groups on the basis of 1,3-butadiene with a cyclic dicarboxylic acid anhydride, and as a cross-linking agent to use a diepoxide (DE-C 21 40 949, DE- A 27 41 453 and

US-A 3 897 514, see also DE-A 22 05 209 and DE-C 22 57 053).

Finally, from EP-B 49 098 there are known masses which can be hot-crosslinked and are cold-crosslinked, and which consist of a combination of two binders, a crosslinker that enables the two binders to crosslink with each other, and common additives (eg binder I may consist of epoxy resin and binder II of maleinized polybutadiene).

These masses also have a disadvantage. This consists in that

the time periods necessary for the cross-linking are relatively long.

The purpose of the invention is to provide masses which can be hot-crosslinked, and a method for producing cold-crosslinked masses, where the disadvantages of the stated state of the art are overcome.

This task is surprisingly solved in the manner stated in the independent claims 1 and 3 and the non-independent claims 2 and 4.

The principle underlying the pulps according to the invention is based on an additive esterification reaction between the primary and/or secondary hydroxyl groups in binder I and the succinic anhydride groups in binder II. Below this, succinic acid half-ester groups are formed which bind together the macro-molecules that form the basis of the binders. The binder matrix thus formed exhibits free carboxyl groups and possibly free hydroxyl groups or free succinic anhydride groups. These functional groups and possibly also the functional groups in binders I and II can react with suitable functional groups in the additives and the substrates with which the masses come into contact.

The production of binders I and II is known in principle.

Binder I

Bamford et al. have described a method for radical polymerization with 4,4'-azo-bis-(4-cyanopentanol-1) as initiator (Trans. Farad. Soc. 15_6 (1960) 932). The radical polymerization with hydrogen peroxide as initiator is described in DE-A 23 23 677, US-A 3 673 168 and 3 714 110 and GB-A 957 788. The anionic polymerization with di-lithium compounds as initiator and conversion of the di-lithium -terminated polybutadiene with ethylene oxide to form a di-hydroxyl-terminated polybutadiene is described in DE-B 24 06 092,

US-A 3 109 871 and DE-A 30 42 559. The ozonolysis of higher molecular rubbers and the reduction of the obtained ozonides to form dihydroxyl-terminated polybutadienes are described in JP-B 9 002-890 and SU patent document 590 314. Polybutadienes substituted at the chain ends are termed telechelically functionalized polymers.

Polymers with a statistical distribution of the hydroxyl groups along the macromolecule length axis are also known. The conversion of a half-ester of a maleinized polybutadiene

with an amino alcohol is described in EP-A 87 526. The addition of formaldehyde to a polybutadiene while forming hydroxymethyl groups is described in German patent application P 33 46 714.5. These polymers bearing hydroxymethyl groups are preferred as binder I.

Binder II

Binder II is usually prepared by addition

of maleic anhydride (MSA) to a polymer based on 1,3-butadiene (see e.g. DE-B 23 62 534).

In special cases, binder II can be prepared by adding MSA to a 1,3-butadiene-based polymer which already exhibits other functional groups, especially reactive silyl groups such as trimethoxysilyl groups. 1,3-butadiene-based polymers bearing such groups can be obtained according to DE-C 30 28 839.

The binders I and II are preferably functionalized homopolymers of 1,3-butadiene. They can also be functionalized copolymers based on - 70 mass percent 1,3-butadiene and ^" 30 mass percent other copolymerizable 1,3-cyclodienes such as isoprene and cyclopentadiene and/or copolymerizable -alkenes such as styrene and ethylene.

The functionalized polymers are usually obtained by functionalizing the base polymers. These can be prepared in a known manner by anionic polymerization, especially with organolithium catalysts, possibly in the presence of a Lewis base as cocatalyst, especially a Lewis base from the group of ethers, tertiary amines and mixtures thereof. They are preferably obtained by Ziegler polymerization, especially with a nickel catalyst.

The additives which catalyze the cold cross-linking of the binders I and II with each other are common acidic esterification catalysts such as (alkyl)benzenesulfonic acids and alkanesulfonic acids and organic nitrogen bases which are mainly not acylated by the crosslinking conditions. Suitable additives are particularly sterically hindered primary and secondary amines, tertiary amines and N-alkylimidazoles. Masses containing such additives are already cross-linked at room or ambient temperatures. Particularly short cross-linking times are achieved when these masses are heated.

The crosslinking times depend on the reactivity of the hydroxyl groups in binder I (primary hydroxyl groups are more reactive than secondary hydroxyl groups), on the reaction temperature and on the nature and quantity of the catalyst as well as on the nature and quantity of other additives.

Common additives are e.g. additives, emollients, fillers and reactive modification components.

The additives are e.g. aging and light protection agents, pigments, dyes that are soluble in the mass, primers, thickeners, flame-retardant additives, smoke-reducing additives and, in special cases, additives that accelerate combustion. The additives can have groups that can react with the anhydride groups in binder II and/or the carboxyl groups in the binder base mass. They are bound in the mass which is cross-linked, so that evaporation and migration losses as well as perspiration (Ausbluhungen) are avoided.

The emollients are ordinary emollient oils and softeners.

They serve to reduce the viscosity of the mass and to make it cheaper.

Suitable fillers are e.g. carbon black, talc, mica, asbestos, kaolin, other natural and synthetic silicates, quartz flour, sand, precipitated and fumed silicic acid, slag flour, fly ash, cement, gypsum, barium sulphate, powder, plate or fiber-form metals and their oxides , carbides, nitrides and borides, aluminum hydroxide, magnesium hydroxide, rubber rumel and synthetic polymers such as PVC, polyalkenes and polystyrene, more specifically in the form of fibres, powders or in a foamed (expanded) state.

The bond between the fillers and the binder primer can under certain circumstances be clearly improved by adding common primers, e.g. such from the group of organo-functional silanes and titanates.

Suitable fillers are further glass fibres, glass microspheres, hollow glass microspheres and other silicate fillers. These can be coated with silanes that carry amino groups or epoxy groups, so that they are able to react with the anhydride groups in binder II and/or the carboxyl groups in the binder base mass.

With fillers that can react directly with the anhydride groups in binder II and with the carboxyl groups in the binder base mass, e.g. the oxides, hydroxides, basic carbonates and carbonates of alkaline earth metals and zinc as well as aluminum oxide and hydroxide, cross-linked masses with high toughness and tear strength (Weiterreissfestigkeit) can be obtained there. Chalk is particularly preferred in this context.

Also organic fillers whose surface exhibits primary and/or secondary hydroxyl groups, e.g. starch, cellulose fibres, cellulose powder, wood flour, ground nut shells, rice husks, cork flour, bark flour etc. is capable of directly reacting with the anhydride groups in binder II and with the carboxyl groups in the binder matrix. Such fillers are bound in the cross-linked mass and can therefore contribute significantly. for strength and elasticity.

The reactive modification components that can react with the anhydride groups in binder II and/or the carboxyl groups in the binder base mass are, for example, not yet cured epoxy resins, phenoplasts, aminoplasts, ketone resins which are possibly hydrogenated, copolymers of maleic anhydride with (^-alkenes, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and other substances which are common as hydroxyl components in the polyurethane area.

The functionalities of the binders I and II must be chosen so that the functionality of binder II is sufficient for the formation of the binder base mass and reaction with the fillers, additives and modifying components. In this connection, a small number of orientation trials is sufficient.

For the formation of the binder base mass, the ratio between the succinic anhydride groups in the binder is usually II

and the primary and/or secondary hydroxyl groups in binder I approx. 1:1 and the corresponding ratio between the product of acid-

number and quantity of binder II and the product of hydroxyl number and quantity of binder I approx. 2:1.

The cross-linking density that can be achieved with the compositions according to the invention can be set within certain limits by varying the hydroxyl and acid numbers, the molecular weight and the proportions of binders I and II calculated on the binder combination, and possibly by means of the nature and quantity of the additives so that depending on the purpose of application can be obtained hard or soft cross-linked masses with high resp. low crosslink density.

In addition to the uses mentioned as examples at the outset, and for which the mass according to the invention is of interest, the following uses must be mentioned: Eraser, shielding agent against electromagnetic and nuclear radiation, noise dampening compounds, cable molding compounds, compounds for the production of sealing rings, solid fuels and rocket fuels. For the latter application, the additives to be used include ammonium perchlorate as well as further substances that affect combustion, e.g. aluminum powder, ferrocene compounds and/or carborane compounds.

The invention will subsequently be described in more detail by means of examples. Here, parts means parts by mass and percent (%) means percent by mass.

Mn for the functionalized polymers that lie

due to binder I, was determined by gel permeation chromatography. Mn for the base polymers that form the basis of binder II was determined by vapor pressure osmometry.

The viscosity of binders I and II was determined at 20°C according to DIN 53 015.

The hydroxyl number (OHT) of binder I was determined

according to DIN 53 240, and the acid value (ST) of binder II was determined according to DIN 53 402.

The gel content of the cross-linking masses was determined indirectly by dissolving a sample in toluene at 200° C, separating the undissolved portion by filtration and gravimetrically determining the dissolved portion.

The hardness according to Shore A for the cross-linking compounds

was determined according to DIN 53 505.

The binders II were based on the base polymers listed in Table 1.

Production of binder IA - IF

The binders IA - ID were prepared by reacting polybutadiene oils with different Mn, whose microstructure corresponded to that of polybutadiene oil A in Table 1 with different amounts of paraformaldehyde in the presence of 0.5% 2,2-methylene-bis-(4-methyl-6- tertiary butylphenol), counted, on the polybutadiene oil as described in German patent application P 33 46 714.5.

Binder IE was prepared as described in EP-A 87 526.

Binder IF is a commercially available polybutadiene that is telechelically functionalised.

Hydroxyl number and viscosity of the binders are indicated

in table 2.

Production of binder IIA - IIC

The binders IIA - IIC were prepared by reacting polybutadiene A, B or C in Table 1 with 7.5% MSA in the presence of 0.05% N-isopropyl-N1-phenyl-p-phenylenediamine, calculated on the mixture of polybutadiene and MSA (190 °C, 2 h).

Acid number and viscosity are given in table 3.

Production of filler-free masses that can be heat-crosslinked, and their heat-crosslinking (examples 1-8)

Portions of 100 g of binder II were mixed with

the quantity of a binder I specified in table 4 at room temperature. The masses produced were cross-linked by heating to 100 °C for 2 hours. The cross-linked masses were weakly coloured, clear and free from cysts.

Production of filler-free masses that are cold cross-linked and their cross-linking (ex. 9-12)

Portions of 100 g of binder IIB were mixed with the amount of binder I indicated in Table 5. Then 1% N-methylimidazole, calculated on the binder combination, was mixed in at room temperature. In example 12, 50 g of an alkaline oil was also added. The masses obtained according to examples 9, 11 and 12 were heated to 45 °C for 15 min. The mass obtained according to example 10 was crosslinked at room temperature during 60 min.

Experiment to demonstrate the dependence of the cross-linking time on the esterification catalyst during cold cross-linking of the masses according to the invention (examples 13 - 20)

Example 13 is a comparison example for the following examples in table 6. The mass used in this experiment contained no catalyst and corresponded to the crosslinkable mass in example 1 in table 4, i.e. that it was obtained by mixing 100 g of binder IIA with 117 g binder IA at 20 °C

( ST Amount of binder . IIA , q.

OHT Amount of binder. IA-'''

Portions of 100 g of binder IIA were mixed at 20 °C with a mixture of 117 g of binder IA and 2.5% calculated on the binder combination, of one of the catalysts listed in Table 6. However, the amount of catalyst in examples 19 and 20 was only 0.2%.

The masses obtained were stored at 20 °C. A thumb pressure test was used to determine the storage time at which the cross-linked mass was already solid, but to what extent still sticky on the surface.

Production of filler-containing masses that can be thermally bonded, and their cross-linking (examples 21 - 29)

Portions of 100 g of binder IIA and 117 g of binder IA (^T^mM^ngdf binder.—IIA_-j_ g. see example 1 in table 4) OHT Amount of binder. IA ^ was mixed in a rolling mill with a filler and in some examples also with a softening oil, the nature and amount of which

are indicated in table 7. The prepared masses were stored at room temperature for 24 h for degassing (the degassing can optionally be carried out in vacuum in a significantly shorter time) and then crosslinked by heating for 3 h to 110 °C (examples 21 - 28).

In example 29, in contrast to the other examples in table 7, the procedure was carried out in such a way that binder IIC from table 3 was used as binder II.

Claims (4)

1. Masses that can be hot-crosslinked, consisting of - a functionalized polymer based on 1,3-butadiene with a number-average relative molecular mass (Hn) of 500-10,000 as binder, - an effective amount of a cross-linking agent that is safe for work hygiene and - ordinary additives, but not those that catalyze cold-crosslinking, characterized by the following additional features: (a) that the combination of binder and cross-linking agent is a combination of two binders which, without the addition of a cross-linking agent, are able to cross-link with each other (binders I and II, in amounts of 10 - 90% by mass calculated on the binder combination), (b) that binder I is a polymer based on 1,3-butadiene with a hydroxyl number of 5 - 200 / mg KOH per g_7, the polymer bearing primary and/or secondary hydroxyl groups, (c) that binder II is a polymer based on 1,3-butadiene with adjacent succinic anhydride groups (maleinized polymer based on 1,3-butadiene) with an acid number of 10 - 300 /mg KOH per gj?, and (d) that the binders I and II are functionalized homopolymers of 1,3-butadiene or functionalized copolymers which are based on at least 70 mass percent 1,3-butadiene and at most 30 mass percent other copolymerizable 1,3- (cyclo)dienes and/or copolymerizable 0C alkenes (incorporation ratio, IR analysis), as the polymers can be modified by isomerisation, hydrogenation or cyclisation and Mn for the functionalised polymers is 500 - 10,000. 2. Masses as stated in claim 1, characterized by : (e) that the binders I and II are each present in an amount of 20 - 80 mass percent calculated on the binder combination, (f) that the Mn for the functionalized polymers that form the basis of the binders I and II is between 1000 and 8000, (g) that the hydroxyl number of binder I is 10 - 150, and (h) that the acid value of binder II is between 20 and 250. 3. Process for producing masses which are cold-crosslinked, where -a functionalized polymer based on 1,3-butadiene with a number average relative molecular mass ("Mn") of 500 - 10,000 as binder, - an effective amount of a hygienically harmless cross-linking agent, - an effective amount of an additive that catalyzes cold cross-linking, and - other common additives mixed in a known manner, characterized by the use of substances as stated in points a - d in claim 1. 4. Procedure as stated in claim 3, characterized in that substances are used as stated in points e - h in claim 2.