BRPI0803860A2 - sealing material composition comprising extended epdm mixture with oil and butyl rubber - Google Patents

Abstract

A rotary strap joint assembly is for use with a strapping machine of type to feed a strapping material around a load, position, tension and seal the strapping material around the load. The belt joint rotor includes a driven wheel having a rotation axis generally perpendicular to the sealed belt handle, a first drive connected to the driven wheel to rotate the driven wheel, and a thrust wheel having a rotation axis parallel to and spaced from the driven wheel. The driven wheel and thrust wheel are movable towards each other and engageable with each other and movable away from and disengageable from each other. A second drive is operably connected with the driven wheel and thrust wheel to move the driven wheel and thrust wheel parallel to their pivot axes on the strap handle plane and outside the strap handle plane. The driven wheel and the pressure wheel are moved in the belt loop plane, and the driven wheel and the pressure wheel are engaged with each other to press the belt between them. The driven wheel is actuated to rotate the strap handle around the load.

Description

"COMPOSITION OF UNDERSTANDING EPDM UNDERSTANDING WITH OIL AND BUTYLE RUBBER"

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a sealing material composition comprising a mixture of oil and butyl rubber extended e-ethylene propylene diene (EPDM) terpolymer in applications such as use in coaxial connection cables, electrical installations, acoustic insulation and sealing. Specifically, the composition of the present invention has unexpected low temperature elasticity and high temperature flow resistance, and may optionally comprise taching resin, polyisobutylene (PIB), fillers and carbon black.

BACKGROUND OF THE INVENTION

Several problems have been observed in the technical state regarding the exposure of sealant compositions at high temperatures. In general, changes in material properties are observed, such as decreased mechanical strength, unwanted flow and loss of material flow.

Several proposals have been put forward for perfecting sealant compositions.

Commercially available products are described as self-adhesive rubber mastic tapes for e-electric products. They are used to insulate and seal moisture from fittings and ends on solid electrical cables and can be bent, stretched and molded around irregular shapes for insulation formation, water sealing and surface protection. They are known to provide superior adhesion and chemical and moisture resistance and can be used in conjunction with vinyl tapes for optimum performance.

EP0244738 describes a butyl rubber based sealant composition, polyisobutylene and, if required, soot, which, in contrast to known sealant compositions of this type, contains 30 to 55% by weight of kaolin. The butyl rubber component preferably consists of a mixture of unsaturated and cross-linked butyl rubber, while the polyisobutylene component preferably consists of a mixture of different molecular weights. In addition to said components, the sealing composition according to the invention may further contain additional components such as pyrogenic silicic acid and low density polyethylene together with the common components.

EP0503124 relates to a polymer compound for the production of container closure gaskets, which in the closed state has a barrier effect preventing the ingress of gaseous or vapor substances such as oxygen and aromatic compounds. , especially benign us, phenyl ether and the like, into the container and / or have an overpressure valve effect at internal vessel pressures of between about 0.3 and 1 MPa (3 and 10bar) and can be produced by mechanical formation of the container. It is composed of thermally plasticized polymer, unformed and subsequently permitting it to be hardened to form the finished elastic shaft directly over or into the container closure ("shell-shaped"). The polymeric compound consists of a mixture of butyl rubber and an unsaturated alpha-olefin monomer polymer and, if desired, one or more other conventional polymer components and additives such as: lubricants, pigments, talc and stabilizers .

DE4323216 relates to a new water-expanding material sealant consisting of a mixture containing at least one expandable agent, an e-lastomer and / or a rubber, and a plasticizer, with expandable substance being incorporated into the total mixture. greater than 20% by weight.

Patent No. L1000712 describes the use of a preparation for insulation / sealing and coating purposes, comprising a non-curable fluid polymer, having a glass transition temperature less than -60 ° C, wherein the polymer has a surface tension. less than 40 mN / m above the glass transition temperature. Preferably, the preparation contains one or more fillers having different particle size and a different particle size distribution.

US4224196 discloses pneumatic strand compositions comprising mixtures of halobutyl rubber, a high unsaturation rubber and an oil-extended ethylene, propylene, and diene terpolymer, wherein the oil-extended terpolymer contains from 25 to 150 phr paraffinic or naphthenic oil. Such triple mixtures provide unexpectedly improved flexural strength even when compared to triple-similar mixtures compositions in which similar amounts of oil are produced, where an oil extended terpolymer is not employed. In addition, methods for preparing such compositions are also described comprising preparing an oil-extended terpolymer, and then mixing the terpolymer with high unsaturated halobutyl rubbers. So-called high unsaturated rubbers include: natural rubber, polybutadiene, SBR (styrene / butadiene copolymer), polychloroprene, among others.

International publication WO2001 / 92411 discloses a butyl rubber composition comprising 100 parts by weight of butyl rubber and 30 to 150 parts by weight of carbon black having a CTAB specific surface area of 30 to 100 m2 / g and particularly contains 10 to 100 parts by weight of a cohesive filler having an average particle diameter of 1 to 40 µm and an apparent ratio of 5 or more and 0.05 to 5 parts by weight of a coupling agent of organometallic compounds. The butyl rubber composition can provide vulcanization molded products capable of effectively sealing carbon dioxide refrigerants without generating bubbles, etc., within it.

DE19653998 describes a high frequency cable having an outer tubular conductor that has a convoluted shape, and formed around it is a glove of insulation material. The connector element has a bushing form with a tube and a coupling part which are screwed together with a seal between them. A butyl rubber selector is between the cable and the tube.

The present invention relates to a sealing material composition comprising a mixture of oil and butyl rubber-extended e-ethylene propylene diene (EPDM) terpolymer.

In another aspect, the composition of the present invention comprises proportionally for 100 phr of an oil-extended EPDM terpolymer, between 10 and 50 phr of butyl rubber.

In another aspect, the material of the present invention exhibits good elasticity at low temperatures and resistance to flow at high temperatures. More specifically, the material of the present invention has properties suitable for applications between -40 and 95 ° C.

In yet another aspect, the composition of the present invention comprises an extended EPDM terpolymer in oil, butyl rubber and polyisobutylene (PIB).

In another aspect, the composition of the present invention comprises proportionally 100 g of an oil extended EPDM terpolymer, 10 to 50 phr of butyl rubber and 20 to 80 phr of polyisobutylene (PIB).

In another aspect, the composition of the present invention comprises an extended EPDM terpolymer in oil, butyl rubber and at least one taching resin.

In another aspect, the composition of the present invention comprises an extended EPDM terpolymer in oil, butyl rubber, polyisobutylene and at least one taching resin. In yet another aspect, the composition of the present invention comprises proportionally to 100 phr of extended EPDM terpolymer. in oil, from 10 to 50 phr of butyl rubber, from 20 to 80 of polyisobutylene and from 40 to 100 phr of at least one taching resin.

In another aspect, the composition of the present invention has other components such as fillers and carbon black.

The composition of the invention may be used for protection and sealing of various substrates, such as coaxial cables. Said composition is also indicated for use in other applications requiring electrical or acoustic insulation.

The summary of the present invention is not intended to describe each disclosed embodiment or each implementation of the present invention. The following is a detailed description illustrative embodiments of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Figures 1A-F are photographs illustrating the test of product stability at high temperatures and how grounding was prepared.

Figures 2A-C are photographs illustrating the low temperature elongation test where Tape 768 could be 50% stretched at -40 ° C.

Figures 3 A-C are photographs illustrating the water column pressure resistance test and the stability analysis after the test.

DETAILED DESCRIPTION OF THE INVENTION The main characteristics of the sealant material described are based on the mixture of extended ethylene propylene diene terpolymer (EPDM) rubber and butyl rubber.

The term "phr" is used herein according to conventional practice, and refers to parts of a given material to 100 parts of a given resin, rubber or elastomer. The oil-extended EPDM terpolymer is considered to be the reference rubber, and thus the other components of the composition of the present invention should be calculated in proportion to the EPDM. Thus "50 phr butyl rubber to 100 phr EPDM" means that in practice, using the unit in kilograms (kg), 50 kg of butyl rubber to 100 kg EPDM would be added.

EPDM is the ASTM designation for the e-ethylene propylene diene terpolymer. EPDM elastomers have a saturated hydrocarbon chain, which provides excellent resistance to oxidation and flexibility even at low temperatures. The glass transition temperature (Tg) of the pre-vulcanized EPDM according to the Polymer Handbook is in the range of -60 to -69 ° C.

The oil extended EPDM terpolymer is the composition based on the present invention, and gives the material adhesion and sealing characteristics. The extension of EPDM with oil is made during its preparation by procedures known in the state of the art. The extended terpolymer contains from 70 to 140 phr of oil, which is used as an EPDM plasticizer, thus making the polymer flexible and contributing to its adhesion property.

For the extension of EPDM, aliphatic oils such as paraffinic and naphthenic oils are particularly suitable for the composition object of the present invention and are known in the state of the art and defined by ASTM D2226. It is important that the oil has adequate viscosity to avoid its viscosity. migration to the surface of the material, especially when subjected to high temperatures. The migration of oil to the surface of the material may compromise its properties, especially with regard to its adhesion to the substrate. Suitable viscosities are particularly in the range of 400 to 600 cPs as measured with VisokimetroBrookfield Model LVF provided by Brookfield EngineeringLaboratories, INC.

Another important property is the purity of the oil used, especially when used in electrical applications, as contamination of the oil with materials such as sulfur can result in attack of copper used in electrical connections. In these cases, the maximum percentage of contaminants should be 100 ppm, which includes sulfur and heavy metals.

Another important property of the oil related to the flash point is when the composition is exposed to high temperatures: the higher the application temperature of the material, the higher its flash point. For applications at 95 ° C , paraffinic oil is particularly suitable as its flash point is approximately 260 ° C, measured according to ISO 2592 ("Cleve-land Open Cup" method). This property should be studied based on the maximum application temperature of the composition of the present invention.

Optionally, paraffinic and naphthenic oils may be added to the composition of the present invention.

Butyl rubber is used to improve material performance at low temperatures by acting as a solid plasticizer and imparting elasticity to the material. This elasticity is of particular importance when the compound of the present invention is exposed to low temperatures.

Butyl rubber is prepared from 2-methyl propene (isobutylene) and 2-methyl-1,3-butadiene (isopropene). The reaction between the two monomers cited above is well known and widely used. The polymerization reaction involves the use of a cationic initiator in the presence of an inert diluent.

Its chain has unsaturated spacings in a long saturated carbon chain, and its degree of unsaturation ranges from 0.5 to 3 mol%. In butyl rubber, isoprene is predominantly inserted into the carbon chain through the addition reaction at positions 1.4 and head - tail arrangement. The glass transition temperature (Tg) is about -65 ° C.

Other raw materials may be added to the composition object of the present invention for the purpose of matching the resulting material to a specific application. One of the particularly suitable feedstocks to be added to the composition is polyisobutylene (PIB).

The addition of GDP to the composition is only possible due to the use of butyl rubber. It is observed that butyl rubber allows compatibility between oil-extended EPDM and polyisobutylene (PIB), but butyl rubber has a similar solubility parameter in value to the parameters of polybutene and paraffinic and naphthenic oils.

GDP is obtained by polymerizing isobutylene in a regular head - to - tail sequence, thus producing a polymer without asymmetric carbon atoms. According to the composition object of the present invention, PIB is used as a liquid plasticizer and also gives the material more fluidity, especially at low temperatures. Optionally 20 to 80 phr of PIB is added to 100 phr of EPDM in the composition.

Tonicifying resins may also be added to the present composition. Such resins are generally used in sensitive adhesives and regulate the rheological properties of the system, such as touch, adhesion and wettability. In polymeric materials such as the composition of the present invention, tannin resins are used for the purpose of improving the processability of the material by decreasing viscosity, promoting a large increase in non-vulcanized mixtures and contributing to polymer self-melting.

Said tonicifying resins have a molecular weight generally between 500 - 2000 and softening point between 50 - 150 ° C. Taching resins include: rosin derivatives, terpenes, hydrocarbon petroleum resins and modified phenolic resins.

To achieve a significant increase in the material's tactile strength, the use of resins with a lower softening temperature is desired. However, in order to obtain materials with high temperature resistance, tannin resins with higher softening temperatures should be used. When the composition of the present invention is used in applications subjected to temperatures of approximately 90 ° C, particularly suitable tannin resins should have a softening temperature ranging from 96 - 150 ° C as measured by the "Ring Ebola" test method. and Bali ", ASTM D3461-76). About 50 - 100phr of at least one taching resin may be added to the composition of the present invention.

Several types of taching resins are available in the market. Examples of such resins include hydrocarbons resins commercially available from PE-TROQUÍMICA UNIÃO (São Paulo, Brazil) under the tradename UNILENE A, resins commercially available from SARTOMER COMPANY (Pennsylvania, United States) under the trade name NORSOLENE W e resins commercially available from SOCCER BRASIL (São Paulo, Brazil) under the trade name RESIDHERE.

Modified phenolic resin-based tonicifying resins are commercially available from ARIZONA CHEMICAL Co (Florida, United States) under the tradename SYLVARES.

In one aspect, the composition object of the present invention is proportionally composed of 100 phr of oil-extended EPDM of about 10-50 phr of butyl rubber, particularly between about 20-50 phr.

In another aspect, the composition object of the present invention is proportionally composed of 100 phr of oil-extended EPDM, from about 10 - 50 phr of silicone rubber, particularly from about 20-50 phr, and from 20-80 phr of polyisobutylene. , particularly between 50 - 80phr.

In another aspect, the composition object of the present invention comprises proportionally for 100 phr of oil-extended EPDM, about 10 - 50 phr of butyl rubber, particularly between about 20-50 phr, between 20 -80phr of polyisobutylene, particularly between - 80 phr, and between 50 - 100 phr of at least one taching resin, particularly between 70 - 100 phr.

Charges may be added to improve electrical and rheological properties. Some of the insulating fillers, and their uses result in also insulating materials. Mineral fillers may also exhibit low thermal conductivity, thus imparting thermal insulating properties to the material. Said filler may range from about 200 - 350 phr to 100 phr of EPDM, depending on the desired characteristics such as density and flowability. Other additives such as amorphous silica or smoke black may be used. Silica (sold under the trade name SACA C5 by the company ITATEX ESPECIALIDADESMINERAIS, São Paulo, Brazil) retains the release of oil (liquid) that can occur when the material is subjected to high temperatures. Carbon black is used as a pigment.

Aluminum hydrosilicate (marketed under the tradename ULTRASIL VN3 by ITATEXESPECIALITIES MINERALS, Sao Paulo, Brazil) can be used to impart homogeneity and regular properties to the material and allow for greater incorporation of filler. It is used in the range of about 2-10%, particularly about 4-8% of the total weight of the total composition.

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EXAMPLE The composition of the present invention may be prepared using the following materials.

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The above compositions were prepared according to the procedure below:

The oil-extended EPDM terpolymer and butyl rubber were mixed in an open two-roller mill (commercially available from BONFANTI de São Paulo, Brazil under the trade name OPEN MILL) for 20 minutes to form a homogeneous mass. To a sigma hammer mill (commercially available from Prillwitz of Buenos Aires, Argentina) at a speed of 800 rpm was added the other components of the composition as follows:

1) The homogeneous mass comprising oil-extended EPDM and butyl rubber was added; the dough was kept under stirring for approximately 5 minutes;

2) A tannin and smoke black resin was added. The mixture was kept under stirring for 5 minutes;

3) The second taching resin was added and the mixture was stirred for 5 minutes;

4) Half the charge of decalcium magnesium carbonate was added and the mixture was stirred for 15 minutes;

5) Polyisobutylene was added and the mixture was kept under stirring for 15 minutes;

6) The remaining charge of decalcium magnesium carbonate was added;

7) After 15 minutes of stirring, aluminum hydrosilicate (SACA C5) was added;

8) After 5 minutes of stirring, the silica (ULTRASIL VN3) was added;

9) The mixture was kept under stirring for 15 minutes until complete homogenization: The product was discharged.

The product obtained was tested for stability at high temperatures (flow), elongation at box temperatures and pressure resistance exerted by a water column.

In order to determine the thermal stability of the composition when used in electrical applications, a grounding cable was prepared using the polymeric composition of the present invention in combination with the PVC tape (such as SCOTCH TAPE 33+, marketed by 3M Company, Minesota, United States). The combination of rubber-based compositions and PVC tape in grounding applications is known to those skilled in the art.

The grounding cable was then placed in a conventional oven at 95 ° C for 24 hours to evaluate any drainage material. After exposure to heat, no evidence of reed was observed, so the material passed the test. Some tested mastic compositions did not pass the test as they had drainage in the cables. The mastic was tested only in combination with a PVC tape because of the need for this application. The material was tested for 7 days at the same temperature and passed this test.

In order to assess the stability and elongation at the temperatures of the composition described herein, a sampled material was cut into a rectangular shape and placed in a freezer at -40 ° C for 24 hours. The longitudinal ends of the sample were fixed with a device that would allow sporadic measurements of material elongation. The devices comprised a metal clip with two metal strips joined at the end by a tip mechanism that allowed the metal strips to be separated and the sample inserted. The elongation of the sample was then determined by manually separating the ends and measuring the displacement of the samples with the help of a ruler. This test can also be performed on a dynamometer.

The composition of the present invention has a minimum of 50% elongation at -40 ° C. This means that half of its size can be manually stretched.

This test is to simulate the application of the material in low temperature places.

In order to measure sealing characteristics, a copper-based grounding cable, the preparation of which has already been described, was installed inside a 4 meter water tower. After 4 hours of testing, the cable was removed from the water tower and the EPDM-based composition was removed from the cable. No evidence of water between the mastic and the cable co-bre was observed. This test was based on the IP68 standard, but the cable tested does not have a situation like this. This is an example of a severe situation.

In order to measure the dynamic stability, a demastic roller was subjected for 24 hours at 85 ° C and after this time, still in the oven, the mastic was pulled from the release paper. The material could preferably have been operated at 85 ° C.

It will be apparent to one skilled in the art that the present invention is not limited to the foregoing illustrative example and may be embodied in other specific forms without departing from the essential attributes thereof. It is therefore desired that the example be considered in all respects as illustrative and not restrictive, reference being made to the appended claims and any changes which may fall within the meaning and equivalence range of the claims and therefore intended to be included here.

Claims (5)

1. Sealant composition for use in electrical installations, characterized by comprising a mixture of extended ethylene propylene diene terpolymer (EPDM) with paraffinic oil, butyl rubber, polyisobutylene and at least one taching resin. 2. Sealant composition for use in electrical installations, characterized in that it comprises: from about 70 to about 140 phr of an oil extended ethylene propylene diene (EPDM) terpolymer, from about 10 to about 50 phr of a butyl rubber: from about 50 to about 80 phr of a polyisobutylene; about 40 to about 100 phr of a resin sealer. Composition according to Claim 2, characterized in that it preferably comprises: about 100 phr of the oil extended ethylene propylene diene terpolymer (EPDM), from about 30 to about 50 phr of a butyl rubber from about 65 to about 80 phr of a polyisobutylene; about 80 to about 100 phr of a resin sealer. Composition according to Claim 2, characterized in that the total sum of the taching deresin system and the polyisobutylene must be less than 170 phr. Composition according to Claim 2, characterized in that it further comprises at least one filler.