CH654583A5 - FLEXIBLE, MICROPOROUS POLYMER SHAPED BODY AND METHOD FOR THE PRODUCTION THEREOF. - Google Patents

Description

The present invention relates to a flexible, microporous polymer molded body made of a sulfur-free, crosslinked polymer material, to a process for its production and to a crosslinkable composition for carrying out this process.

In a preferred embodiment, the flexible, microporous molded body according to the invention has a backing material made of an inert polymer, which has a resistance to an electrolyte for electrical collector batteries that is at least equivalent to that of the microporous molded body made of the sulfur-free, crosslinked polymer material ss .

In the polymer molded body according to the invention, the average pore size is less than 2 micrometers, preferably less than 1 micrometer. The molded polymer body can be suitably manufactured with various degrees of flexibility 60 and this flexibility can, if desired, result in complete re-placement to a relatively stiff material which, however, is not brittle and, accordingly, has flexibility and strength properties which were previously the case with Sulfur-cured materials were unknown. The preferred flexible, microporous molded article has a nonwoven non-woven backing, and this molded article has a number of properties previously unknown to similar materials, such as e.g.

a stretchability of more than 25%, a tensile strength of up to 7 k Pa and above, etc.

The process according to the invention is a continuous process for producing the flexible, microporous polymer molded body, which comprises irradiating a crosslinkable composition with electron beams at previously unknown low radiation doses, and likewise the crosslinked polymer material, which is e.g. on a backing material, in thicknesses that were previously not possible.

In the commonly used electrical collector batteries, such as In the well known 12 volt batteries used in automobiles, there is a need for diaphragms between the battery plates to be as thin as possible so as to obtain the lowest possible electrical resistance. At the same time, they were looking for a battery diaphragm that was reasonably flexible and not prone to damage during use, such as due to fragility damage.

In general, a battery diaphragm is required as a spacing element that prevents two plates from touching each other and causing a short circuit between them. At the same time, the diaphragm should not hinder the flow of the electrolyte. A small pore size is also desirable to prevent dendrite growth that can occur between adjacent plates. Such dendrite growth leads to a short circuit in the battery. For one or more of the reasons stated above, it is not only necessary to increase the distances between the battery plates, but also to use battery diaphragms.

Various other problems have also been encountered with battery plate flaking associated with the use of antimony or calcium additives. Peeled deposits on the bottom of the battery have similarly caused short circuits or premature failure of the battery. Because of this, the search has been made for batteries that can be manufactured in such a way that the battery diaphragm can be attached around the plates, or that it can be mounted in a serpentine arrangement, thus isolating each plate from the other.

However, the battery diaphragms known from the prior art are all quite stiff and not very flexible, and complicated shapes could only be produced with great difficulty. In addition to the problems listed above, the overvoltage on the electrodes, particularly the anode, had the effect that, as is well known, battery water had to be refilled.

Only recently has the overvoltage problem been solved to such an extent that maintenance-free batteries can be used to a sufficient degree. This is essentially the result of better plate or electrode materials and better battery diaphragms.

In the prior art, cheap and fairly short-lived battery separators have been made using paper nonwovens. However, these had disadvantages, and instead of paper, batteries have higher quality diaphragms, which consist of hardened natural rubber compositions. A general disadvantage associated with the use of rubber or natural rubber battery diaphragms is that a sulfur curing process is not only capital intensive, which is a batch process, but this process is also expensive in terms of labor and energy consumption. The sulfur curing of Natur3 654 583

rubber to form microporous moldings results in stiff and brittle products. In addition, to maintain the porosity, which is ensured by silica gel, a battery diaphragm must be subjected to sulfur curing in a water-filled autoclave. The repeated raising and lowering of the temperature of large amounts of water is accordingly associated with high energy consumption.

In addition, a sulfur curing process requires high capital investments in terms of mixing devices, size reduction devices, extruders and a whole range of vulcanizers, etc.

When rubber compositions are crosslinked, the cured moldings are tested for their fragility and fracture behavior. If the process is not carried out very carefully and carefully, the sulfur-cured diaphragms will often show brittle crack problems. It is also difficult to maintain dimensional tolerances, for example, he-20 require hardened sheets from which battery diaphragms are made to be regrind.

As a practical solution to the problems mentioned above which occur in connection with sulfur-cured rubber products, fabrics or nonwovens impregnated with phenol formaldehyde resin 25 have been used as battery diaphragms. The polyphenol resins are generally cured to a B condition and rigid battery diaphragms are obtained.

Difficulties in dealing with phenols and formal-30 dehyde, the removal of their residues and the disadvantages of the end product, e.g. Accordingly, the large pore size and the low resistance to oxidation have hitherto restricted the use of this process very much, as has the use of the moldings produced in this way. 35 Another approach to solving the problems known in the prior art is to use a fleece impregnated with polyvinyl chloride (PVC), which has been proposed as a battery diaphragm. However, the manufacture of such impregnated nonwovens requires the use of solvent systems and the removal of solvents, which contributes to undesirable waste and pollution problems.

A PVC fleece must also be heat-embossed or hot-embossed in order to achieve the necessary ribbing or perforation, to ensure the electrolyte flow and to achieve sufficient strength.

Melt-foamed polypropylene mats have been proposed as another material for battery diaphragms. However, the pore sizes of the mat were too large and unacceptable in this case, and the electrical resistance characteristics were also difficult to control.

These tests carried out according to the prior art also required a completely new mass of machinery and novel process technologies, and it was no longer possible to use the existing work opportunities which existed in connection with the sulfur curing of natural rubber.

A number of microporous molded articles and processes for making these permeable microporous products have been described, for example, in US Pat.

2 274 260.2 329 322.2 336 754.2 686 142.2 637 876,

3,298,869.3 450 650.3 773 540.3 890 184.3 900 341 and Canadian Patent No. 1,020,184, and

65 The citations given in these patents extend the description of the current state given above.

It has now been found that microporous sheet materials with predeterminable adapted flexibility,

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Improved toughness and extensibility can be made of a polyol lyacrylate and used as a microporous agent, whereby a microporosity is guaranteed and hydrated silica gel with a degree of hydration of also other properties which are better than the 50-70%.

Most previously known sulfur-cured microporous This composition, the previously un-molded rubber body for this purpose. A far greater flexibility, which contains 5 known crosslinking agents, has been achieved by means of molded articles according to the invention without having superior properties, namely the other properties and advantages of the agent used, with previously unknown low radiation doses. During items such as of a battery diaphragm, sacrificed typically for networking according to the state of the art. The new polymer molding radiation dose according to the invention for non-analog products and highly sensitive has flexibilities which, from sheet-like layered compositions of natural rubbers, lead to prayer to stiff but not brittle plates. range from 20-104 to 40-104 Gy is specified for styrene bu-

The flexible, microporous polymer-tadiene or nitrile-butadiene rubber from 14-104 to molded body according to the invention is characterized in that it has a molded 15-104 Gy and for EPDM (ethylene-propylene-diene copoly-body from a sulfur-free cross-linked polymer material mer) from 12- IO4 to 14-104 Gy, according to the invention requires that this sulfur-free cross-linked microporous polymer composition for effective cross-linking requires only a polymer material with an ester from the class of the polyol-po radiation dose of less as 6-104 Gy and preferably lyacrylate and polyol polymethacrylate or with a content of about 3 to 4-104 Gy. Although crosslinking would be possible at higher doses of crosslinked esters belonging to this class, namely at 6-104 Gy and above, a rubber containing silicon dioxide and finally a medium one up to 10-104 Gy suffers from a number of inherent pore sizes less than 2 microns. 20 shafts, e.g. the flexibility, among them, and therefore a particularly preferred flexible, microporous form - for economic reasons for the production of products body has a backing material, which is made of an inert with the best properties radiation, polymer and is resistant to one Dose less than 6-104Gy. If the electrolytes for electrical collector batteries are reduced, the radiation dose to such an extent should be advantageous, in particular that of the microporous molded body from which sulfur is used in an industrial company.

free, cross-linked polymer material at least equivalent It is assumed that the non-cross-linked

is. solutions, as well as the crosslinked compositions

A preferred polymer molded article according to the invention are novel material compositions.

is present in particular as a battery diaphragm, which is easy.A new process is also brought into any desired shape and provided with a different one, which can be produced for the production of microporous shaped bodies of such thickness and which is also used, e.g. Sheets, and can apply to the crosslinkable rubber together with a backing material. Is used, for example natural rubber, copolymers polymer moldings according to the invention can be used as micropo made of ethylene and propylene, or mixtures of crosslinkable

red filters, enzyme carrier materials, diffusion agents etc. rem rubber and ethylene-propylene rubbers (copo-

are used and have a variety of advantages, 35 polymers). The method according to the invention has proven to be

which are explained in more detail below. ders useful because it has a number of advantages

According to a preferred aim of the present invention, which brings with it those which have so far not been achievable, a polymer molded body is proposed which is used as conventional technologies, such as e.g. the sulfur battery diaphragm can be used and which carries a cross-linking of natural rubber to microporous molded article underlayer, which was previously unknown in its kind. Get 40 per. The method according to the invention thus provides a material with combined properties of a continuous mode of operation, whereby a shanks, such as e.g. a low electrical resistance, reduced number of process steps occurs, and there is a reduced amount of microporous material (it is possible to use already existing mixing devices and pre-combination with the underlay material) and with improvement devices for the production of microporous sheets of tensile, tear and toughness, ductility and resilience or shapes. In addition, they are resistant to tearing. The preferred detailed procedural steps in the inventive method of the molded article according to the invention, which has a backing material which, however, were necessary according to the prior art, constitutes a synergistic combination and appeared to be particularly unfavorable with regard to the combination of the two microporous of the environmental problems and the elimination of the secondary molded articles and the flexible underlay material. 50 products, as well as in terms of energy consumption, for the

The process for producing the shrinkage according to the invention has been brought.

A further advantage of the process according to the invention is that a sulfur-free, crosslinkable mixture consists in the fact that a very thin, flexible, microporous crosslinkable rubber can be produced with the class of polyolpoly molded bodies, which in turn allows

Crosslinking belonging to acrylates and polyol-polymethacrylates 5s a thin or even thinner layer of a microporous agent together with hydrated silica gel as micro-polymer material together with a suitable underlayer.

to combine pore-forming agent for the formation of a shaped body of continuous material. When executing the

Extruded and continuously molded process, the molded article can be produced without electron beam irradiation in a dose less than the risk of material damage, without handling 6-104 Gy, and after it has been irradiated, it can be crosslinked into 60 problems and without material defects , such as Brittleness

a dryer is continuously failing by dispensing the water.

makes silica gel microporous. According to the present invention, as mentioned above, the present molded article can be produced with a high degree of flexibility, and the present invention also relates to a crosslinkable composition, solvent systems being excluded and the method for carrying out the process according to the invention. 65 when heating and cooling large amounts of water, which is characterized in that it is bypassed as a crosslinkable material, as is the batch process technology, material sulfur-free, crosslinkable rubber, as sulfur. The advantages of the present free crosslinking agent for this purpose are a polymethacrylate or Po - driving consists in the discovery of procedural steps,

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which lead to a flexible material which, due to rial, is to be treated by means of the further strip rolling mill for its further suitable mixing and co-processing.

cross-linkable rubber, for example natural chewing. The well-mixed

Tschuk, ethylene-propylene rubber (copolymer) or wettable mixture into an extruder (9), in which

Mixtures of these materials and a suitable crosslinking agent extrude a sheet of, for example, 0.84 cm thick for this purpose, and crosslinking by means of electrons, and finally in a water bath (10).

irradiation in the presence of hydrated silica gel. A carrier fleece (11) is then

will. While it is quite clear that the adjusters have added microporous moldings. A carrier fleece wetting at higher doses would be possible, as is required, for example, in order not to damage the rubber during vulcanization at up to 8 or even 10 • 104 Gy, some 10 are clearly evident. Paper is favorably used as the carrier fleece

Disadvantages, for example economic and security technology applied. After a role of the extruded sheet, niche factors, as well as material deteriorating influences in a suitable size, for example with regard to the diameter

etc., accordingly the preferred range is 4 • sers, this roll is ready for curing.

104 Gy and less, i.e. at the radiation dose that is necessary, each wound material roller (12) is then dig with in order to transfer the desired composition within useful wheels (13) into a vulcanizer (14), in which time to crosslink. Water is heated to an appropriate temperature

When crosslinking the poly used according to the invention, the crosslinking is effected at about 177 ° C.

mermaterials, together with the admixture of Vernet- The temperature is generally with a constant detergent, the hydrated silica gel material appears to increase the eye speed of 4.44 ° C per minute, whereby the effectiveness of the radiation does not seem to substantially stop an air pressure, so as not to destroy the leaves,

influence, but it turns out that the addition of hydra- Once the microporous molded body is vulcanized,

tized silica gel, when irradiated with it is cooled and removed from the vulcanizer,

preferred dose values of 3 to 4 • 104 Gy a final pro- In order again to avoid material deterioration

duct, e.g. Battery diaphragm, with superior properties, is the cooling of the molded body in a cooling device

to receive those that have not yet been achieved. 2s direction (15) carefully under pressure. Then done

A detailed description of such drying of the hardened shaped body is again given below in

Given compositions. The networkable combination of a procedural procedure, in a

Settlement contains a crosslinkable rubber, for example suitable drying device (16). In preconditioning

Natural rubber, polyisoprene and various variants rang (17) the carrier fleece is hardened and dried.

thereof, styrene-butadiene rubber, nitrile-butadiene rubber 30 sheets removed.

or mixtures thereof; These can be used individually. To the extent that certain damage is observed in the crosslinking, but with a significant advantage if they are observed together and because it requires a single operation to be used with ethylene-propylene rubber (removing unwanted damage, everyone must the latter can also be ground as a cross-linkable rubber, sulfur-crosslinked shaped body, to which it can be used), and as a cross-linking agent for the desired surface. This is because the genetic materials, preferably a polyol diacrylate, have suitable dimensions and surface properties, such as polyol triacrylate, a polyol tetraacrylate, a polyol dimeth- also the final thickness and ribbing of the battery diacrylate, a polyol trimethacrylate, a polyol tetramethacry phragmas can be produced. Then the molded body is used in lat or mixtures thereof. A typical example of a device (18) cut to width and deflected, for advantageous crosslinking agents, trimethylol-propane-tri-o to get to the packaging and to be dispatched is methacrylate. It is postulated that crosslinking means that in the attached FIG. 2: (1) carbon black, (2) crosslinking agent contributes significantly to the properties of the end-product antioxidant, (3) natural rubber, (4) hydrated product . licagel with 66% water, (5) EPM (ethylene propylene copoly

mer) not always, (6) crosslinking agent, (7) banbary mix. The invention will now be explained in more detail with the aid of the accompanying drawings, (8) mill, (9) any second gene that may be present: mill, (10) Extruder, (11) water bath, (12) rollers, (13)

1 is a schematic representation of the essential nonwoven carrier fleece which may be present, (14)

Steps in a previously conventional method for producing water bath, (15) device for electronically irradiating microporous moldings by sulfur curing with doses of ^ 3-410.4 Gy, (16) drying device of a suitable rubber composition, and so and (17) devices for completion.

FIG. 2 is a schematic illustration of the invention. With reference to FIG. 2, it should be noted that the mixture is a process. the components take place in the order in which they are

A conventional method is shown in FIG. 1, in which the following is indicated, although in the drawing it is chem in a Banbury mixer (1) natural rubber (2), as if it were introduced at the same time. For the manufac

Sulfur crosslinking agent (3), hydrated silica gel (4) ss depended on the main batch and the mixture of the polymer material (about 66% H20) and suitable auxiliaries (5), e.g. Dipherials are described in more detail below.

Combine nyl guanidine mixing aids, oil etc. together. The description given here serves to mix the advantages. The sequence or the sequence of the addition of the method according to the invention can be shown and its materials can be varied, but the method steps shown in FIG. 2 will be explained.

mean the crosslinking agent and the hydrated silica gel «0 The process according to the invention is carried out in continuous

last added. The mixing is carried out in mixing devices of the same procedure. In a suitably large one

(6), (7) and (8) mixed until a suitable outlet (material Banbury mixer or a number of suitably sized mixers

distance) temperature was reached. So then the stems are processed, the compositions taken here further processed, e.g. mixed on one. A next approach can be mixed at a time

Two-roll cooling device, until again suitable, which is sufficient so that a two-roll deep-drawing

nete temperature for the mixture is reached. Then the device can be kept in continuous operation, the

A suitable belt is then attached to this device by means of a thoroughly mixed mixture in one

Strip mill manufactured; often it is necessary to insert the mate extruder so that one can work continuously

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maintained wisely. Accordingly, the Banbury direction is removed and the moisture is maintained. The mixer and the two-roll mills and the Ex hold. The mixture should be operated in a powdery, free-flowing form in such a way that there is continuously a continuous flow.

Ensure that the material is fed to the extruders. The cross-linkable composition is hydrated. The extruded sheet exiting an extruder is silica gel with a degree of hydration of 50-70%, preferably

is placed in a water bath to contain the water content of 60-70%.

Silica gel as shown in Figure 2. The size is below the degree of hydration. However, if the water content can be suitably adjusted in another way, the water bath can also be omitted if necessary. However, it must be guaranteed that i0 ——w X 100%

that the appropriate amount of water is present in the mixture + w.

A suitable shaping roller to understand the ones desired, where Mw is the mass of the silica gel

Bumps, ribs or other patterns can be used NEN water and Ms the mass of the silica gel without the water, the molded body, which means from the extruder and 1S.

emerges from the water bath to give the desired surface structure. Advantageously, the B. main batch process can:

exercise of the sheet at elevated temperature, e.g. 43.3 ° C to the main batch production is desirable for the

60.0 ° C. After shaping, the continuation of a uniform mixture of the cross-linkable composites

Lich moving sheet in a water bath (if necessary), in this example introduced ethylene-propylene copolymer and out of this into an electron beam (EPM) and / or natural rubber. Accordingly, there is

Device in which the composition cures the main batch of natural rubber, EPM, UV stabilizer and with the specified typical dose of 3 bis and carbon black. The amount of EPM and natural

4 • 104 Gy. rubber granulate (1000 g as an example) are placed in a

The hardened 2s bury mixer is introduced from the electron beam device and the mixture is then mixed for about 3 days into a dryer in which it takes up to 4 minutes (at the speed in the second course) until the water of hydration is removed from the silica gel, and the Temperature has risen to approximately 121 ° C. Then the microporosity is obtained. From the dryer, the UV stabilizer and / or soot black (which also comes out, the sheet can optionally act as a UV stabilizer) are added, and the batch is subjected to finishing treatment, the 30 at a temperature of about 135 ° C. taken. The GeMaterial cut to width and distracted, and in the usual total time is about 5 minutes. During this period, the way is packaged. a small amount of warm water (of about 65.6 ° C) according to an object of the present invention, the rotor blades and the body of the Banbury mixer, a battery diaphragm can now be easily made, passed through to provide suitable temperature control for use in the process of the invention The method used is 35 and the total time to produce the main batch when the diaphragm is made in this way should be about 5 minutes, the main batch having the desired surface structures and the batch that comes from the Banbury mixer emerges, is obtained for rubber diaphragms to a variety of thicknesses, including thicknesses that have previously been applied to the cold two-roll mill and have been known, forms a band.

These separators can also be used together with an Un- 40 C. mixing process:

The material to be produced is then used to obtain a required amount of the main batch (250-300 g), which previously had been rolled for rubber separators in a two-roll cold mill until the mixture was smooth. According to the present invention (5 minutes) and then in the Banbury-Mi process, a sheet with a very low resistance value can be kept together with diphenyl-guanidine (DPG), which has a reduced thickness of the porous processing aid brought in. The container temperature of the material shows, as well as an improved tensile strength, Reissfe-Banbury mixer is 60 ° C, without heating or cooling stability, toughness and resistance to steam being passed through the rotor blades. The Mitigation. speed of the Banbury mixer is a superior product could also be made "slow" speed, and when the temperature reaches 50 by 65.6 ° C according to the inventive method, half of the required amount of a cooperating combination a crosslinkable, rehydrated silica gel and a crosslinking agent, such as, for example Croporous rubber-based material and a flexible trimethylol propane trimethacrylate (TMPTM) added. Sheets used. The composition is mixed until it turns again

Temperature reached 65.6 ° C, and so then the re-generalized example 55 hydrated silica gel material is added and mi-A rehydration of silica gel: see until it reaches 65.6-71.1 ° C again. The combination - The moisture content of silica gel is first cast then removed. There is a very uniform vote and then some correction is applied before the mixture is received and the total dwell time during which the rehydration is carried out. Rehydration levels from Banbury mixer is about 8 minutes. Then 66.5% or 69.0% is typically applied, but 60 this mixture on a two-roll agitator during 7 the rehydration can range from 65 to 70%. mixed up to 8 minutes, the two rollers having the Tempe one thousand grams of silica gel are placed in a mixer of 60 ° C. The sheet rolled out in this way is brought in and the corrected amount of water is then cut into narrow pieces with a gel and soaked in hot water at a speed of 800 to 900 cubic centimeters per minute for 30 to 45 seconds at 50-850 C and thus pumped in. The pumping time of water should then be quite 65 calendered to produce surfaces and / or be short, on the order of a few millimeters, possibly a backing material such as e.g. Paper, or grooving, otherwise the mixture will get too wet. When finished, add a heat-set polyester mat. (The last rehydration cycle, the mixture of the previous material is significantly more preferred as it follows

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The temperature of the two Ka process is suitable, styrenebutadiene rubber is 54.4 ° C. The calendered sheet is cut into suitable (SBR), nitrile butadiene rubber (NBR) or blends, such as 38.1 cm x these materials. Of course, it is assumed that 22.86 cm and is used in an electron beam device before use are SBR and NBR polymers that radiate. After curing by means of electron beams, 5 are not thermally set. All of the above-mentioned poly-den then these leaves dried at about 50 ° to 100 ° C, meren can be used in mixtures with each other to give the desired porosity. As a component for imparting toughness, flexibility and other desirable characteristics for the Basiszu-D. Continuous process: composition, i.e. for natural rubber, synthetic In a continuous process instead, 10 rubber or mixtures of these materials, as indicated earlier in the previous example, showed ethylene propylene rubber (copolymers) unexpectedly and after the rolling of a sheet in an extruder was desired good Properties in combination with purchase leads. A molded body, which obtained from the extruder Tschuk or even as the only represented materials. Although being introduced into a water bath at a temperature of 50-85 ° C according to the prior art, ethylene-propylene copolymers so as not to lose any water that often serves as silica gel hydra- 15 as either ethylene-propylene polymer or ethylene ion . Depending on the ability to control the amount of water or propylene monomer or ethylene-propylene rubber in the molded body, this can be drawn, a clearer and more precise loading water bath can be used or it may not be necessary. Drawing in that this material is referred to as a “copoly-the water bath at this interface of the process, consisting of ethylene and propylene”, which is a simple means of carefully regulating the composition of various proportions of these monomers to disposal. From this water bath, the ex- will make up in the range of 20 to 80% ethylene and the molded body will comprise the rest of propylene through shaping rolls. (However, it is clearly guided to produce a sheet with a desired surface character called the "rubber" property of the matestics, such as with ribs or other primary materials called ethylene propylene rubber.)

pimples. If so desired, a sub-

Bedding material to be added to the polymer material. Common propylene rubber was the one that had an ethylene

An extruded sheet of a polymer, i.e. contained about 60% by weight of copolymer, the nes rubber or rubber and / or ethylene-propylene-ethylene content making up about 60% by weight of the copolymer,

Copolymer blend in this molding step with egg and polymer having a Mooney viscosity of about 30

provided underlay material. 30 had. This product is commercially available and as

The sheet is again known from the shaping rollers in EPCAR 306 and developed by B. F. Goodrich & Co.

immersed in a water bath, which is kept at a temperature of Although other EPDM terpolymers examined are about 25-85 ° C and then it has been turned into an electron, the most preferred polymer is the beam irradiation device in which the ethylene-propylene copolymer is introduced.

Sheet with a dose of preferably 4 • or 104 Gy less 35 A more flexible product is obtained when chewing is irradiated. Irradiation doses of more than 6 • chuk, e.g. Natural rubber as the predominant or 104 Gy, and sometimes even at this value, causes the main component to be applied to the polymer, which undesirably becomes brittle until the composition becomes brittle. to and including 100% of the curable material. Out of the radiation device, this is maintained continuously. However, better strength and stiffness of moving sheets will be kept in a dryer if larger amounts of ethylene-propylene-copoly are brought in, in which the rehydration water of the silica gel is used, for example amounts of 20 to 20 is removed , so that the desired porosity and po- 30% and even of 35% and more flexibility is obtained. From this device the sheet comes in when the ethylene-propylene rubber is used in amounts of only 3 of the finishing devices, by using it in length and up to 5%. Appropriately cross-linked micropo-cut in width, and 45 suitable shaped containers were obtained in suitable containers by being packaged only in the natural state before it was dispatched and used for rubber or only ethylene-propylene rubber, mixed use in conventional car batteries serves. conditions of these materials or mixtures of these materials

Although in the general example a procedure in other crosslinkable rubbers described previously on a small scale, one procedure was mentioned in which the following enlarged scale was used to cure wetting agents using the same procedure.

steps as described in the example, and The crosslinking agent for the above-mentioned compositions as well as in the continuous process settings, either for the rubber, given the procedure. for example, natural rubber or ethylene propylene chew. The description of the various components for chuk or copolymer or mixtures thereof is typical — the precursor compositions are given below, 55 usually an acrylate or a methacrylate of a polyol. To illustrate the scope of the present invention, the polyol can be a di-, tri- or tetravalent polyol, illustrative and also to further representations of the above- and the acrylate or methacrylate can be given with the hydroxyl-given embodiment of the invention. groups of the polyol are formed. The polyol can contain 3 to. Natural rubber no. Comprise 1 and 10 carbon atoms. Typical polyols from which smoked leaves with a Mooney viscosity of 60 and which derive acrylates and methacrylates are around 25 ° to 30 ° at approx. 79 ° C. With regard to plasticity, trimethylol-propane, pentaerythritol, triaethylene-glycol, natural rubber should be in the range from 14 to 18 (Rheome-1,6-hexanediol, etc. Mixtures of the acrylates and / or ter-50 scanning. Instead of natural rubber, you can The methacrylates of the above polyols are also suitable as crosslinking agents, synthetic polyisoprenes, various solvents and trimethylol-propane-trimethacrylate stereospecific variants and polymers thereof with natural - in particular and most suitable for the execution of the rubber of the present invention. Of the methacrylate or another polymer which is preferred for the acrylate species according to the invention the methacrylates are preferred because of their

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much less toxicity problems compared to acrylates.

In combination, the typical crosslinking agents are used in amounts of 0.5 to 3 parts by weight per 100 parts by weight of crosslinkable rubber, ethylene-propylene copolymers or mixtures of the materials.

However, it has been found that for certain shaped articles which are produced by the process according to the invention, such as for battery diaphragms, the amount of ethylene-propylene copolymers in the mixture is preferably in the range of 35 to 15%, and particularly preferably about 20%. However, the ratios of natural rubber to ethylene-propylene polymers can be such as e.g. 90: 10.80: 20.75: 25.70: 30.60: 40, 50:50 and up to 100 parts of ethylene-propylene rubber were also classified as favorable. Suitable microporous moldings were obtained by using only crosslinkable rubber, for example natural rubber or only ethylene-propylene copolymers, which was cured with the crosslinking agents mentioned above. The preferred combinations of the two materials are given above. Different proportions of these components result in different properties and accordingly allow tailor-made properties to be obtained.

In addition to the materials listed above, carbon black can be used in particular as an additive, which increases the stability (in the form of a UV stabilizer) and accordingly the porous molded body is produced in this way, or with the addition of an antioxidant (UV stabilizer).

Usually, the carbon black is used in an amount of 0.5 to 3 parts by weight per hundred parts of the polymer, and the stabilizer in an amount of 0.5 to 2 parts by weight per hundred parts.

Among the various stabilizers, a bu-tylated p-cresol-dicyclopentadiene was found to be preferred. It is available from Goodyear Tire & Rubber Co. under the tradename Wingstay-L. Other stabilizers are such as e.g. styrenated diphenylamine, namely Wing-stay 29, which is also available from Goodyear Tire & Rubber Co., and polymerized 1,2-dihydro-2,2,4-trimeth-yl-quinoline (Flecto Age) from Monsanto Co. ).

The hydrated silica gel powder serves to impart porosity to the polymers and is readily available. One type of this is Hi-Sil 233, available from Pittsburgh Plate Glass Co. In general, the surface area of the hydrated silica gel should be greater than 50 m2 per gram (according to the B.E.T procedure) and the minimum oil absorption should be about 100 cm3 oil or more per 100 g silica gel (according to ASTM test procedure D-281-31).

The amount of hydrated silica gel used, expressed in proportions of hydrated silica gel relative to rubber, should range from 3.0: 1 to 8.0: 1 by weight, and preferably 3.5: 1 to 5.5: 1 in terms of weight with a silica gel hydration degree of 65 to 70% and up to a maximum of 75%. In general, the higher the ratio of hydrated silica gel to rubber, the lower the electrical resistance of the battery diaphragm. The greater the silica gel ratio, the less is the flexibility of the hardened shaped body.

Irradiation of the novel compositions is preferably carried out by means of an electron beam device which has an output of 850 kW and 50 mA and which is available under the name Dynamitron from Radiation Dynamics, Incorporated in Melville, New York. Any electron beam device capable of delivering a radiation dose of 6 • 104 Gy is suitable for the practice of the present invention. The irradiation time and the irradiation intensity are a function of the sheet or shaped body thickness. Accordingly, each reference mentioned here in this description with respect to the irradiation level relates to the same sheet or shaped body thickness.

With the preferred use of an underlayer, it has been found that the open structure of a non-woven fleece with an oversized “pore size” is suitable for a battery diaphragm, but the flexibility of a suitable fleece to which a layer of the microporous molded body can be securely attached , has not previously been used to obtain a suitable flexible microporous layer. Accordingly, a flexible nonwoven and a fairly stiff and brittle microporous sheet material that is still of substantial thickness are not used. The use of a flexible microporous molded body and a flexible backing material, in combination of the two, allows the use of a thinner sheet of the microporous molded body, which is very advantageous not only because of the lower resistance in a battery, but also because of the fact that a more flexible sheet is less tends to be pierced and that there is no tendency to damage when the material is strongly bent, as does the flexible nonwoven, and this does not appear to result in any further disadvantage for the combination when used in an electrolyte. At the same time, the backing material can be irradiated under safe conditions and it provides a sufficient "body" for the polymer material, thereby allowing a polymer material to be applied in a thin thickness of only 0.012 to 0.02 mm. However, a thicker layer, such as up to 0.06 cm, can also be used. Accordingly, the particular form of application will determine the suitable thickness of the microporous layer which lies on the underlay material.

As underlay materials, polyester in nonwoven heat-bonded form (in distinction to the adhesive-bonded form) of nonwovens has been discovered to be particularly desirable. An average fiber length in these nonwovens is usually about 2.03 cm. These nonwovens are, for example, from duPont and Co under the trade names such as Sontara 8000 available.

The properties of such nonwovens are determined on the basis of their electrical resistance and their tensile and tear strength. For battery diaphragms, the electrical resistance resulting from the addition of the underlay material should not be greater than 1 m 2 2.54 cm2 / 0.00254 cm thick. The tensile strength should be about 68.96 • 104 N / m2 and the elongation (stretchability) should be 40%. The tensile strength for a base fabric of approx. 34 g per 0.91 m2 in the standard size should be about 22 and more in the processing direction and about 13 and more in the determination of the tensile strength by clamping according to ASTM method Dl 682-65 Direction transverse to the processing direction. In this method of determining tensile tear strength, each of the two ends of a test strip is gripped and then the strip is pulled apart until it tears, for example using an Instron tester. This test device is one which is equipped with jaws which hold the ends of the strip-shaped sample. Such test devices are usually used in the paper industry. The values given above correspond to approximately 10 kg in the processing direction and approximately 5.9 kg in the direction transverse to the processing direction.

8th

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

654 583

In general, base fabrics or nonwovens are available with a weight of 25 to 75 g / m2.

Typical ranges for the property of the above materials are the following:

Tear strength when clamped in N: In machine direction:

Cross machine direction:

Tear resistance by clamping in%: In machine direction:

Cross machine direction:

Weight in g / m2:

Impact resistance (tear resistance) after rubbish:

89.07-133.6 53.46- 80.15

Tongue tear resistance (tear resistance when tearing off a tongue of 25 mm) stated in kg: s In machine direction:

Cross machine direction:

about 9.42 N 1.4113.83 N

In the present specification, parts mean parts by weight unless otherwise specified.

To further illustrate the present invention 25-50, specific examples are given in the following tables-50-120. These examples show different properties and 41-75 characteristics of the variations of the compositions according to the invention. However, it should be noted that these examples mentioned 133.61-178.15 N îs only describe preferred embodiments of the present invention. It should be noted again that parts or percentages that are given here are percentages by weight or parts by weight, unless stated otherwise.

Table I

Effectiveness of the various stabilizers

Natural rubber, g EPM, g

Hydrated silica gel, g moisture in silica gel,%

TMPTM, g Wingstay 29, g Wingstay-L, g Total dose, 104 Gy dose rate, passage, 104 Gy thickness, in mm

Electrical resistance m £ 2 cm2

mfl cm2 / mm Weight loss in chromic acid,% Evaluation of the diaphragms before submission to fluorescent light Evaluation after submission to exposure to fluorescent light for 7 days

A 80 20

360 66.5

3.0

1.0

4th

2nd

0.457

361 787

6.0 <

B

80 20 360 66.5 3.0 1.0

4 2

0.381 323 838 10.0

Formulation C 80 20 360 66.5 3.0

1.5

4th

2nd

0.584 465 787 7.5

Flexible

No cracking within 7 days, but slight cracking after 2 weeks

Very little cracking

Flexible after 2 weeks, little cracking after multiple folds

D 80 20 360 66.5 3.0

2.0

4th

2nd

0.508 387 762 8.0

Very good, no cracking after 1 month

Table II

Effect of EPM mixed with natural rubber and effect of the different levels of TMPTM:

Natural rubber, g EPM, g

Hydrated silica gel, g moisture in silica gel,% dry silica gel, g TMPTM, g assessment

(MO4 Gy thickness, in mm Electrical resistance mfi cm2 mQ cm2 / mm

Tear resistance, N / m2 • 9.81 104 expansion,%

Weight loss in chromic acid,% evaluation

4- 104Gy thickness, in mm Electrical resistance:

mQ cm2 mQ cm2 / mm tensile strength, Pa expansion,%

Weight loss in chromic acid,% evaluation

E

F

G

H

I.

J

K

L

100

90

80

75

80

80

80

-

-

10th

20th

25th

20th

20th

20th

100

360

360

360

360

360

360

360

360

66.5

66.5

66.5

66.5

66.5

66.5

66.5

61.9

-

-

-

-

-

26

3rd

3rd

3rd

3rd

1.0

1.5

2.0

1.5

•quality

0.432

Mix 0.457

0.406

minor mixing problems

0.381

0.406

- easy to process

0.381

undetectable

-very flexible -

flexible, some crack on one

-flexible

0.559

355 635

100.65 • 104 2

50.0

very flexible ■ * and flanged

0.432

323 737

104.87 • 104 5

35.0 - flexible

stiffer

0.432

297 686

151.76 • 104 3

8.0

page

0.457

0.457

0.381

stiff

387 323

838 711

103.04-104 -3

8.0 30.0

Crack on one - *

Side, stiff

258 660

6.0 ■ flexible

0.483

0.584

387 660

8.0

irregular mix, easy to process

0.737

348

348

310

368

323

303

368

374

813

762

762

965

787

787

762

508

9.98

10.55

15.12

17.58

-

-

-

-

14

13

10th

5

-

-

-

-

stiff, strong cracking when folded

0.762

387 508

2.0 stiff, hard, cracked

Table III

Formulation studies with different silica gel hydration levels and ratios, from rehydrated silica gel to gum

formulation

1-A

1-B

1-C

1-D

1-E

Natural rubber, g

80

80

80

80

80

EPA, g

20th

20th

20th

20th

20th

Hydrated silica gel, g

360

433

480

433

468

Moisture of the hydrated

Silica gel,%

66.5

66.5

66.5

69.0

69.0

Wingstay-L, g

2nd

2nd

2nd

2nd

2nd

DPG, g

2nd

2nd

2nd

2nd

2nd

Soot-black, g

0.5

0.5

0.5

0.5

0.5

TMPTM, g

1.5

1.5

1.5

1.5

1.5

Theoretical humidity,%

51.5

53.4

54.47

55.4

56.3

plasticity

-

14

16

15

18th

Time in the Banbury mixer, min.

8th

8th

8th

8th

8th

Extraction temperature according to Banbury, ° C

71-74

71-74

71-74

71-74

71-74

Rolling time (60 ° C.), Min.

7

7

7

7

7

Water bath temperature, ° C

85

85

85

85

85

Time in water bath, sec.

40

40

40

40

40

Calander temperature, ° C

54

54

54

54

54

O\

Lìì 4X Ol 00

w

Table III A

Physical and electrical properties of formulations with different degrees of silica gel rehydration and ratios of rehydrated silica gel to rubber

Wording

0 • 104 Gy

1-A

1-A (B) *

1-B

1-B (B)

1-C

1-C (B)

1-D

1-D (B)

1-E

1-E (B)

Thickness in mm

0.406

0.635

0.406

0.559

0.381

0.533

0.381

0.584

0.457

0.535

Electrical resistance:

mQ cm2

297

348

252

206

194

219

232

271

213

232

mQ cm2 / mm

737

559

610

381

508

406

610

457

457

432

Tensile strength, Pa

148.31 • 104

613.68-104

182.76 • 104

554.40 • 104

185.51 • 104

599.98 • 104

184.45 • 104

589.68 • 104

158.11 • 104

710.34 • 104

Strain, %

10.0

35.0

6.8

37.3

6.0

42.0

18.0

36.1

7.3

36.0

Breaking load, N

-

-

8.44

40.13

7.16

42.28

8.04

43.65

9.81

47.19

Weight loss in

not fixed-

Chromic acid,% total porosity, cc / g

-

-

47

63

0.498

68

47

62

55

60

Pore modal value

diameter (s)

-

-

-

-

0.059

-

-

-

-

-

Humidity, %

48.0

-

49.0

50.0

-

51.0

-

51.9

-

Assessment very flexible

4-104 Gy

Thickness, in mm

0.432

0.635

0.381

0.533

0.381

0.432

0.381

0.508

0.508

0.533

Electrical resistance:

mQ cm2

284

297

194

206

194

161

200

194

245

245

mQ cm2 / mm

660

457

508

381

508

381

533

381

483

457

Tensile strength, Pa

144.8 • 104

585.56 • 104

145.48 • 104

820.7 • 104

170.3 • 104

787.55 • 104

146.86 • 104

647.58 ■ 104

167.55 • 104

704.85 • 104

Strain, %

4.0

30.0

1.0

35.0

1.0

34.5

1.0

33.0

1.0

28.0

Breaking load, N

6.68

47.19

8.44

51.21

6.68

46.79

8.93

485.6

Weight loss in

Chromic acid,%

8.0

5.3

8.0

6.0

8.0

5.0

9.0

8.0

BP **

10.0

Alcohol porosity,%

-

-

47.0

61.0

61.0

66.0

46.0

63.0

50.0

66.0

Total porosity, cc / g

-

-

0.513

0.894

0.533

-

0.499

-

0.525

-

Pore modal value

diameter

-

0.041

8.5

0.043

-

0.064

-

0.053

-

Humidity, %

48.0

-

48.0

-

48.0

-

51.0

-

53.0

-

evaluation

• flexible and rigid

(B) -Sontara pad BP - broken pieces

13 654 583

Using the procedure of the above general backed material, the percent elongation 20 to my example is to make a blend which is 90%, and preferably 40 to 60% and the tensile strength is essentially natural rubber (254 g), TMPTM (7 , 6 g), up to 8400 k Pa. It is possible to use very flexible moldings

Hi-Sil (472 g, silica gel) and water (875 g). To manufacture from this- customizable shapes if you have thin leaves

A cured product was obtained from this mixture, which uses 5 which have a high extensibility,

An electrical resistance of 1.3 mQ 2.54 cm2 / and thicker leaves result in tough, even stiff products.

0.0025 cm and 33 mQ 2.54 cm2. The above shows that the flexibility (not brittleness) is easily measured relative ratio of silica gel to rubber in combination by means of the 180 ° bending test and the combination according to the invention.

Hang with the reduced resistance, however, the settings will easily meet this test.

Flexibility reduced. I0 It should be noted once again that the specified here

Another composition was obtained by values generally being suitable to achieve chemically desirable one following the procedure of the general example, and to achieve compositions, but also the components used were the following: approx. 40 kg mentioned values can be used, around process variables

of 80% natural rubber; 15% EPCAR 306; Deliver 5% pliolite compared to a standard process.

S-6F (on material made of 82.5% styrene, and the rest of butadiene- i5 A cheap measuring method for the acceptable porosity rubber (SBR) available from the Goodyear Tire & Rubber is the alcohol porosity and it should be in the range of 45 to

Co.); approx. 63.1 kg Hi-Sil 233 (coloidal silica gel); 0.6 kg, 75%. Other porosity measurements were made in the

TMPTM; approx. 0.8 kg DPG and approx. 109 kg water. The above examples were given and accordingly a shaped body crosslinked by electron beams can be assumed from which values comparable to those produced with the above composition, which is suitable, are suitable in 2o the values cited above.

Various forms or configurations of the networked The electrical resistance standards for battery

Materials to be brought, because the networked phrases are easily reached, and typically for a

is suitable for ultrasonic welding. If the microporous moldings according to the invention

Talking battery diaphragms can be made, the level of 1.0 to 2.5 mQ 2.54 cm2 / 0.0025 cm acceptable,

in the form of an envelope that completely covers a battery plate 25 As already mentioned above, the dimensional stability

envelops. It should be noted that before the cross-linking of the shape of the mold during processing, extraordinarily rol-butadiene rubber and the nitrile-butadiene rubber are good and the procedure is carried out carefully

(NBR) is not yet networked, i.e. that it is not unnecessary to grind the end product. These advantages

heat-set polymers. regarding the undocumented and provided with underlay material

In the examples described above, the weight ratio of the materials according to the invention shows the various

lust in chromic acid a typical raw test to see the unsaturated benefits of the present invention.

degree of polymeric composition - When used in a battery, the battery

len, as well as the useful life, and acceptable separators or diaphragms according to usual test procedures,

Weight loss is less than 35%. The weight losses that are well known in the art are tested,

also indicate the completeness of the hardening and the 35, such as by means of a cold start test («cold crank-

Effectiveness of the networking process. mg ») and using the« J-240 »test according to the SAE test

The shelf life or storage stability is similar. '

of the hardened microporous molded body is an indicator of the lifespan of the product, and you get closer- If you use a fleece, the thickness of the battery can

values by going down to 0.013 to 0.02 cm to fluorescent light expo separators,

kidney. Typically, the composition should survive this exposure well, although a typical thickness of the separator in the range of at least 14 days, before 0.03 to 0.05 cm (with backing material) and 0.025 to

Cracks occur or flexibility is reduced. 0.05 cm without underlay material. It should be stated again

The various measurements of the toughness of the cross-linked hold that with a battery separator the effectiveness of the th material without the backing material are the following: The 45 thinner polymer materials on a fleece, in combination

Tensile strength should be in the range of 1400 to 2800 k Pa, determined according to the two tests above, and it shows and preferably in the range of 2100 to 2800 k Pa. (Here too, the advantage of the method according to the invention.

C.

1 sheet of drawings

Claims (15)

654 583 PATENT CLAIMS 1. Flexible, microporous polymer molded body, characterized in that it is a molded body made of a sulfur-free cross-linked polymer material, that this sulfur-free cross-linked microporous polymer material with an ester from the class of polyol polyacrylates and polyol polymethacrylates or with a mixture of these Class belonging esters is cross-linked rubber, which contains silicon dioxide and has an average pore size of less than 2 micrometers. 2. The molded polymer body according to claim 1, characterized in that it has a base material which consists of an inert polymer and has a resistance to an electrolyte for electrical collector batteries which is at least equivalent to that of the microporous molded body made of the sulfur-free, crosslinked polymer material. 3. Polymer molding according to claim 2, characterized in that the base consists of a non-woven fibrous inert polymer, the fibers of which are heat-bonded to one another. 4. The molded polymer body according to claim 1, characterized in that the rubber is 95 to 75% by weight of natural rubber and 5 to 25% by weight of ethylene-propylene rubber. 5. The molded polymer body according to claim 1, characterized in that the rubber with polyol diacrylate, poly-ol triacrylate, polyol tetraacrylate, polyol dimethacrylate, poly-ol trimethacrylate, polyol tetramethacrylate or with a mixture of those listed in this list Polyol esters is cross-linked. 6. The molded polymer body according to claim 5, characterized in that the polyol is trimethylolpropane. 7. The molded polymer body according to claim 1, characterized in that the microporous flexible polymer material made of crosslinked rubber has a 180 ° flexibility and an average pore size of less than 1 micrometer, and that the rubber is an ethylene-propylene rubber or another rubber or a Mixture of these rubbers is. 8. The molded polymer body according to claim 7, characterized in that the rubber is a mixture of a natural rubber and an ethylene-propylene rubber with a natural rubber content of 75 to 95% by weight. 9. The molded polymer body according to claim 7, characterized in that the rubber is a mixture of 80% by weight of natural rubber and 20% by weight of ethylene-propylene rubber, the latter containing about 60% by weight of copolymerized ethylene monomer. 10. The molded polymer body according to claim 7, characterized in that it has a base which consists of an inert polymeric fiber material made of fibers which can be joined together and which has at least the same resistance to an electrolyte for electrical collecting batteries as the microporous molded body made of the sulfur-free one , cross-linked polymer material. 11. The molded polymer body according to claim 10, characterized in that the underlay material is a non-woven fibrous polymer material made of polyester. 12. A process for the production of a molded polymer body according to claim 1, characterized in that a sulfur-free crosslinkable mixture of crosslinkable rubber with the crosslinking agent belonging to the class of polyol polyacrylates and polyol-poly-methacrylates is continuously extruded together with hydrated silica gel as a microporous agent to form a molded body and crosslinked the shaped body continuously by electron radiation in a dose of less than 6-104 Gy and, after it had been irradiated, made it microporous in a dryer by dividing the water out of the silica gel. 13. The method according to claim 12, characterized in that the crosslinkable mixture is a natural rubber, a synthetic polyisopore rubber, a styrene butadiene rubber, a nitrile butadiene rubber or a mixture of rubbers mentioned in this list 10 includes. 14. The method according to claim 12 or 13, characterized in that a mixture of natural rubber, with a copolymer of ethylene and propylene is used, the amount of natural rubber i5 is 65 to 95 wt .-% and the rest of ethylene-propylene - rubber is. 15. The method according to claim 12, characterized in that in the continuous production of the molded body, the mass to be molded is extruded and into the final 20 tige form is brought, and is provided with an underlayer of an inert polymer material in the form of a non-woven heat-bonded nonwoven. 16. Crosslinkable composition for carrying out the method according to claim 12, characterized in that 25 that it contains sulfur-free, cross-linkable rubber as the cross-linkable material, a polymethacrylate or polyacrylate of a polyol as the sulfur-free cross-linking agent therefor, and hydrated silica gel with a degree of hydration of 50-70% as the micropore-forming agent. 17. The composition according to claim 16, characterized in that it contains 80% by weight of natural rubber and 20% by weight of ethylene-propylene rubber, which contains 60% by weight of ethylene as a copolymer, as a crosslinking agent, trimethylolpropane trimethacrylate and as 35 microporous agent hydrated silica gel with 60-70% degree of hydration contains that it also contains carbon black and a stabilizer, and that it can be cross-linked by electron beam radiation in a dose of less than 6-104 Gy.